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1612.01175
Benjamin Eysenbach
Benjamin Eysenbach, Carl Vondrick, Antonio Torralba
Who is Mistaken?
See project website at: http://people.csail.mit.edu/bce/mistaken/ . (Edit: fixed typos and references)
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recognizing when people have false beliefs is crucial for understanding their actions. We introduce the novel problem of identifying when people in abstract scenes have incorrect beliefs. We present a dataset of scenes, each visually depicting an 8-frame story in which a character has a mistaken belief. We then create a representation of characters' beliefs for two tasks in human action understanding: predicting who is mistaken, and when they are mistaken. Experiments suggest that our method for identifying mistaken characters performs better on these tasks than simple baselines. Diagnostics on our model suggest it learns important cues for recognizing mistaken beliefs, such as gaze. We believe models of people's beliefs will have many applications in action understanding, robotics, and healthcare.
[ { "version": "v1", "created": "Sun, 4 Dec 2016 20:45:42 GMT" }, { "version": "v2", "created": "Fri, 31 Mar 2017 16:36:53 GMT" } ]
2017-04-03T00:00:00
[ [ "Eysenbach", "Benjamin", "" ], [ "Vondrick", "Carl", "" ], [ "Torralba", "Antonio", "" ] ]
TITLE: Who is Mistaken? ABSTRACT: Recognizing when people have false beliefs is crucial for understanding their actions. We introduce the novel problem of identifying when people in abstract scenes have incorrect beliefs. We present a dataset of scenes, each visually depicting an 8-frame story in which a character has a mistaken belief. We then create a representation of characters' beliefs for two tasks in human action understanding: predicting who is mistaken, and when they are mistaken. Experiments suggest that our method for identifying mistaken characters performs better on these tasks than simple baselines. Diagnostics on our model suggest it learns important cues for recognizing mistaken beliefs, such as gaze. We believe models of people's beliefs will have many applications in action understanding, robotics, and healthcare.
new_dataset
0.959383
1702.05891
Feng Zhu
Feng Zhu, Hongsheng Li, Wanli Ouyang, Nenghai Yu, and Xiaogang Wang
Learning Spatial Regularization with Image-level Supervisions for Multi-label Image Classification
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multi-label image classification is a fundamental but challenging task in computer vision. Great progress has been achieved by exploiting semantic relations between labels in recent years. However, conventional approaches are unable to model the underlying spatial relations between labels in multi-label images, because spatial annotations of the labels are generally not provided. In this paper, we propose a unified deep neural network that exploits both semantic and spatial relations between labels with only image-level supervisions. Given a multi-label image, our proposed Spatial Regularization Network (SRN) generates attention maps for all labels and captures the underlying relations between them via learnable convolutions. By aggregating the regularized classification results with original results by a ResNet-101 network, the classification performance can be consistently improved. The whole deep neural network is trained end-to-end with only image-level annotations, thus requires no additional efforts on image annotations. Extensive evaluations on 3 public datasets with different types of labels show that our approach significantly outperforms state-of-the-arts and has strong generalization capability. Analysis of the learned SRN model demonstrates that it can effectively capture both semantic and spatial relations of labels for improving classification performance.
[ { "version": "v1", "created": "Mon, 20 Feb 2017 08:21:58 GMT" }, { "version": "v2", "created": "Fri, 31 Mar 2017 08:49:43 GMT" } ]
2017-04-03T00:00:00
[ [ "Zhu", "Feng", "" ], [ "Li", "Hongsheng", "" ], [ "Ouyang", "Wanli", "" ], [ "Yu", "Nenghai", "" ], [ "Wang", "Xiaogang", "" ] ]
TITLE: Learning Spatial Regularization with Image-level Supervisions for Multi-label Image Classification ABSTRACT: Multi-label image classification is a fundamental but challenging task in computer vision. Great progress has been achieved by exploiting semantic relations between labels in recent years. However, conventional approaches are unable to model the underlying spatial relations between labels in multi-label images, because spatial annotations of the labels are generally not provided. In this paper, we propose a unified deep neural network that exploits both semantic and spatial relations between labels with only image-level supervisions. Given a multi-label image, our proposed Spatial Regularization Network (SRN) generates attention maps for all labels and captures the underlying relations between them via learnable convolutions. By aggregating the regularized classification results with original results by a ResNet-101 network, the classification performance can be consistently improved. The whole deep neural network is trained end-to-end with only image-level annotations, thus requires no additional efforts on image annotations. Extensive evaluations on 3 public datasets with different types of labels show that our approach significantly outperforms state-of-the-arts and has strong generalization capability. Analysis of the learned SRN model demonstrates that it can effectively capture both semantic and spatial relations of labels for improving classification performance.
no_new_dataset
0.950273
1703.10631
Jinkyu Kim
Jinkyu Kim and John Canny
Interpretable Learning for Self-Driving Cars by Visualizing Causal Attention
null
null
null
null
cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deep neural perception and control networks are likely to be a key component of self-driving vehicles. These models need to be explainable - they should provide easy-to-interpret rationales for their behavior - so that passengers, insurance companies, law enforcement, developers etc., can understand what triggered a particular behavior. Here we explore the use of visual explanations. These explanations take the form of real-time highlighted regions of an image that causally influence the network's output (steering control). Our approach is two-stage. In the first stage, we use a visual attention model to train a convolution network end-to-end from images to steering angle. The attention model highlights image regions that potentially influence the network's output. Some of these are true influences, but some are spurious. We then apply a causal filtering step to determine which input regions actually influence the output. This produces more succinct visual explanations and more accurately exposes the network's behavior. We demonstrate the effectiveness of our model on three datasets totaling 16 hours of driving. We first show that training with attention does not degrade the performance of the end-to-end network. Then we show that the network causally cues on a variety of features that are used by humans while driving.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 18:37:49 GMT" } ]
2017-04-03T00:00:00
[ [ "Kim", "Jinkyu", "" ], [ "Canny", "John", "" ] ]
TITLE: Interpretable Learning for Self-Driving Cars by Visualizing Causal Attention ABSTRACT: Deep neural perception and control networks are likely to be a key component of self-driving vehicles. These models need to be explainable - they should provide easy-to-interpret rationales for their behavior - so that passengers, insurance companies, law enforcement, developers etc., can understand what triggered a particular behavior. Here we explore the use of visual explanations. These explanations take the form of real-time highlighted regions of an image that causally influence the network's output (steering control). Our approach is two-stage. In the first stage, we use a visual attention model to train a convolution network end-to-end from images to steering angle. The attention model highlights image regions that potentially influence the network's output. Some of these are true influences, but some are spurious. We then apply a causal filtering step to determine which input regions actually influence the output. This produces more succinct visual explanations and more accurately exposes the network's behavior. We demonstrate the effectiveness of our model on three datasets totaling 16 hours of driving. We first show that training with attention does not degrade the performance of the end-to-end network. Then we show that the network causally cues on a variety of features that are used by humans while driving.
no_new_dataset
0.943034
1703.10642
Hyungjun Kim
Hyungjun Kim, Taesu Kim, Jinseok Kim and Jae-Joon Kim
Deep Neural Network Optimized to Resistive Memory with Nonlinear Current-Voltage Characteristics
14 pages
null
null
null
cs.ET cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Artificial Neural Network computation relies on intensive vector-matrix multiplications. Recently, the emerging nonvolatile memory (NVM) crossbar array showed a feasibility of implementing such operations with high energy efficiency, thus there are many works on efficiently utilizing emerging NVM crossbar array as analog vector-matrix multiplier. However, its nonlinear I-V characteristics restrain critical design parameters, such as the read voltage and weight range, resulting in substantial accuracy loss. In this paper, instead of optimizing hardware parameters to a given neural network, we propose a methodology of reconstructing a neural network itself optimized to resistive memory crossbar arrays. To verify the validity of the proposed method, we simulated various neural network with MNIST and CIFAR-10 dataset using two different specific Resistive Random Access Memory (RRAM) model. Simulation results show that our proposed neural network produces significantly higher inference accuracies than conventional neural network when the synapse devices have nonlinear I-V characteristics.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 19:04:55 GMT" } ]
2017-04-03T00:00:00
[ [ "Kim", "Hyungjun", "" ], [ "Kim", "Taesu", "" ], [ "Kim", "Jinseok", "" ], [ "Kim", "Jae-Joon", "" ] ]
TITLE: Deep Neural Network Optimized to Resistive Memory with Nonlinear Current-Voltage Characteristics ABSTRACT: Artificial Neural Network computation relies on intensive vector-matrix multiplications. Recently, the emerging nonvolatile memory (NVM) crossbar array showed a feasibility of implementing such operations with high energy efficiency, thus there are many works on efficiently utilizing emerging NVM crossbar array as analog vector-matrix multiplier. However, its nonlinear I-V characteristics restrain critical design parameters, such as the read voltage and weight range, resulting in substantial accuracy loss. In this paper, instead of optimizing hardware parameters to a given neural network, we propose a methodology of reconstructing a neural network itself optimized to resistive memory crossbar arrays. To verify the validity of the proposed method, we simulated various neural network with MNIST and CIFAR-10 dataset using two different specific Resistive Random Access Memory (RRAM) model. Simulation results show that our proposed neural network produces significantly higher inference accuracies than conventional neural network when the synapse devices have nonlinear I-V characteristics.
no_new_dataset
0.949995
1703.10645
Igor Fedorov
Igor Fedorov, Ritwik Giri, Bhaskar D. Rao, Truong Q. Nguyen
Relevance Subject Machine: A Novel Person Re-identification Framework
Submitted to IEEE Transactions on Pattern Analysis and Machine Intelligence
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a novel method called the Relevance Subject Machine (RSM) to solve the person re-identification (re-id) problem. RSM falls under the category of Bayesian sparse recovery algorithms and uses the sparse representation of the input video under a pre-defined dictionary to identify the subject in the video. Our approach focuses on the multi-shot re-id problem, which is the prevalent problem in many video analytics applications. RSM captures the essence of the multi-shot re-id problem by constraining the support of the sparse codes for each input video frame to be the same. Our proposed approach is also robust enough to deal with time varying outliers and occlusions by introducing a sparse, non-stationary noise term in the model error. We provide a novel Variational Bayesian based inference procedure along with an intuitive interpretation of the proposed update rules. We evaluate our approach over several commonly used re-id datasets and show superior performance over current state-of-the-art algorithms. Specifically, for ILIDS-VID, a recent large scale re-id dataset, RSM shows significant improvement over all published approaches, achieving an 11.5% (absolute) improvement in rank 1 accuracy over the closest competing algorithm considered.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 19:21:55 GMT" } ]
2017-04-03T00:00:00
[ [ "Fedorov", "Igor", "" ], [ "Giri", "Ritwik", "" ], [ "Rao", "Bhaskar D.", "" ], [ "Nguyen", "Truong Q.", "" ] ]
TITLE: Relevance Subject Machine: A Novel Person Re-identification Framework ABSTRACT: We propose a novel method called the Relevance Subject Machine (RSM) to solve the person re-identification (re-id) problem. RSM falls under the category of Bayesian sparse recovery algorithms and uses the sparse representation of the input video under a pre-defined dictionary to identify the subject in the video. Our approach focuses on the multi-shot re-id problem, which is the prevalent problem in many video analytics applications. RSM captures the essence of the multi-shot re-id problem by constraining the support of the sparse codes for each input video frame to be the same. Our proposed approach is also robust enough to deal with time varying outliers and occlusions by introducing a sparse, non-stationary noise term in the model error. We provide a novel Variational Bayesian based inference procedure along with an intuitive interpretation of the proposed update rules. We evaluate our approach over several commonly used re-id datasets and show superior performance over current state-of-the-art algorithms. Specifically, for ILIDS-VID, a recent large scale re-id dataset, RSM shows significant improvement over all published approaches, achieving an 11.5% (absolute) improvement in rank 1 accuracy over the closest competing algorithm considered.
no_new_dataset
0.945349
1703.10661
Md Shopon
Mithun Biswas, Rafiqul Islam, Gautam Kumar Shom, Md Shopon, Nabeel Mohammed, Sifat Momen, Md Anowarul Abedin
BanglaLekha-Isolated: A Comprehensive Bangla Handwritten Character Dataset
Bangla Handwriting Dataset, OCR
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bangla handwriting recognition is becoming a very important issue nowadays. It is potentially a very important task specially for Bangla speaking population of Bangladesh and West Bengal. By keeping that in our mind we are introducing a comprehensive Bangla handwritten character dataset named BanglaLekha-Isolated. This dataset contains Bangla handwritten numerals, basic characters and compound characters. This dataset was collected from multiple geographical location within Bangladesh and includes sample collected from a variety of aged groups. This dataset can also be used for other classification problems i.e: gender, age, district. This is the largest dataset on Bangla handwritten characters yet.
[ { "version": "v1", "created": "Wed, 22 Feb 2017 07:57:14 GMT" } ]
2017-04-03T00:00:00
[ [ "Biswas", "Mithun", "" ], [ "Islam", "Rafiqul", "" ], [ "Shom", "Gautam Kumar", "" ], [ "Shopon", "Md", "" ], [ "Mohammed", "Nabeel", "" ], [ "Momen", "Sifat", "" ], [ "Abedin", "Md Anowarul", "" ] ]
TITLE: BanglaLekha-Isolated: A Comprehensive Bangla Handwritten Character Dataset ABSTRACT: Bangla handwriting recognition is becoming a very important issue nowadays. It is potentially a very important task specially for Bangla speaking population of Bangladesh and West Bengal. By keeping that in our mind we are introducing a comprehensive Bangla handwritten character dataset named BanglaLekha-Isolated. This dataset contains Bangla handwritten numerals, basic characters and compound characters. This dataset was collected from multiple geographical location within Bangladesh and includes sample collected from a variety of aged groups. This dataset can also be used for other classification problems i.e: gender, age, district. This is the largest dataset on Bangla handwritten characters yet.
new_dataset
0.965381
1703.10667
Chih-Yao Ma
Chih-Yao Ma, Min-Hung Chen, Zsolt Kira, Ghassan AlRegib
TS-LSTM and Temporal-Inception: Exploiting Spatiotemporal Dynamics for Activity Recognition
16 pages, 11 figures
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent two-stream deep Convolutional Neural Networks (ConvNets) have made significant progress in recognizing human actions in videos. Despite their success, methods extending the basic two-stream ConvNet have not systematically explored possible network architectures to further exploit spatiotemporal dynamics within video sequences. Further, such networks often use different baseline two-stream networks. Therefore, the differences and the distinguishing factors between various methods using Recurrent Neural Networks (RNN) or convolutional networks on temporally-constructed feature vectors (Temporal-ConvNet) are unclear. In this work, we first demonstrate a strong baseline two-stream ConvNet using ResNet-101. We use this baseline to thoroughly examine the use of both RNNs and Temporal-ConvNets for extracting spatiotemporal information. Building upon our experimental results, we then propose and investigate two different networks to further integrate spatiotemporal information: 1) temporal segment RNN and 2) Inception-style Temporal-ConvNet. We demonstrate that using both RNNs (using LSTMs) and Temporal-ConvNets on spatiotemporal feature matrices are able to exploit spatiotemporal dynamics to improve the overall performance. However, each of these methods require proper care to achieve state-of-the-art performance; for example, LSTMs require pre-segmented data or else they cannot fully exploit temporal information. Our analysis identifies specific limitations for each method that could form the basis of future work. Our experimental results on UCF101 and HMDB51 datasets achieve state-of-the-art performances, 94.1% and 69.0%, respectively, without requiring extensive temporal augmentation.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 20:45:00 GMT" } ]
2017-04-03T00:00:00
[ [ "Ma", "Chih-Yao", "" ], [ "Chen", "Min-Hung", "" ], [ "Kira", "Zsolt", "" ], [ "AlRegib", "Ghassan", "" ] ]
TITLE: TS-LSTM and Temporal-Inception: Exploiting Spatiotemporal Dynamics for Activity Recognition ABSTRACT: Recent two-stream deep Convolutional Neural Networks (ConvNets) have made significant progress in recognizing human actions in videos. Despite their success, methods extending the basic two-stream ConvNet have not systematically explored possible network architectures to further exploit spatiotemporal dynamics within video sequences. Further, such networks often use different baseline two-stream networks. Therefore, the differences and the distinguishing factors between various methods using Recurrent Neural Networks (RNN) or convolutional networks on temporally-constructed feature vectors (Temporal-ConvNet) are unclear. In this work, we first demonstrate a strong baseline two-stream ConvNet using ResNet-101. We use this baseline to thoroughly examine the use of both RNNs and Temporal-ConvNets for extracting spatiotemporal information. Building upon our experimental results, we then propose and investigate two different networks to further integrate spatiotemporal information: 1) temporal segment RNN and 2) Inception-style Temporal-ConvNet. We demonstrate that using both RNNs (using LSTMs) and Temporal-ConvNets on spatiotemporal feature matrices are able to exploit spatiotemporal dynamics to improve the overall performance. However, each of these methods require proper care to achieve state-of-the-art performance; for example, LSTMs require pre-segmented data or else they cannot fully exploit temporal information. Our analysis identifies specific limitations for each method that could form the basis of future work. Our experimental results on UCF101 and HMDB51 datasets achieve state-of-the-art performances, 94.1% and 69.0%, respectively, without requiring extensive temporal augmentation.
no_new_dataset
0.94625
1703.10714
Donghyun Kim
Donghyun Kim, Matthias Hernandez, Jongmoo Choi, Gerard Medioni
Deep 3D Face Identification
9 pages, 5 figures, 2 tables
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a novel 3D face recognition algorithm using a deep convolutional neural network (DCNN) and a 3D augmentation technique. The performance of 2D face recognition algorithms has significantly increased by leveraging the representational power of deep neural networks and the use of large-scale labeled training data. As opposed to 2D face recognition, training discriminative deep features for 3D face recognition is very difficult due to the lack of large-scale 3D face datasets. In this paper, we show that transfer learning from a CNN trained on 2D face images can effectively work for 3D face recognition by fine-tuning the CNN with a relatively small number of 3D facial scans. We also propose a 3D face augmentation technique which synthesizes a number of different facial expressions from a single 3D face scan. Our proposed method shows excellent recognition results on Bosphorus, BU-3DFE, and 3D-TEC datasets, without using hand-crafted features. The 3D identification using our deep features also scales well for large databases.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 23:49:23 GMT" } ]
2017-04-03T00:00:00
[ [ "Kim", "Donghyun", "" ], [ "Hernandez", "Matthias", "" ], [ "Choi", "Jongmoo", "" ], [ "Medioni", "Gerard", "" ] ]
TITLE: Deep 3D Face Identification ABSTRACT: We propose a novel 3D face recognition algorithm using a deep convolutional neural network (DCNN) and a 3D augmentation technique. The performance of 2D face recognition algorithms has significantly increased by leveraging the representational power of deep neural networks and the use of large-scale labeled training data. As opposed to 2D face recognition, training discriminative deep features for 3D face recognition is very difficult due to the lack of large-scale 3D face datasets. In this paper, we show that transfer learning from a CNN trained on 2D face images can effectively work for 3D face recognition by fine-tuning the CNN with a relatively small number of 3D facial scans. We also propose a 3D face augmentation technique which synthesizes a number of different facial expressions from a single 3D face scan. Our proposed method shows excellent recognition results on Bosphorus, BU-3DFE, and 3D-TEC datasets, without using hand-crafted features. The 3D identification using our deep features also scales well for large databases.
no_new_dataset
0.944995
1703.10818
Liying Chi
Liying Chi, Hongxin Zhang and Mingxiu Chen
End-To-End Face Detection and Recognition
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Plenty of face detection and recognition methods have been proposed and got delightful results in decades. Common face recognition pipeline consists of: 1) face detection, 2) face alignment, 3) feature extraction, 4) similarity calculation, which are separated and independent from each other. The separated face analyzing stages lead the model redundant calculation and are hard for end-to-end training. In this paper, we proposed a novel end-to-end trainable convolutional network framework for face detection and recognition, in which a geometric transformation matrix was directly learned to align the faces, instead of predicting the facial landmarks. In training stage, our single CNN model is supervised only by face bounding boxes and personal identities, which are publicly available from WIDER FACE \cite{Yang2016} dataset and CASIA-WebFace \cite{Yi2014} dataset. Tested on Face Detection Dataset and Benchmark (FDDB) \cite{Jain2010} dataset and Labeled Face in the Wild (LFW) \cite{Huang2007} dataset, we have achieved 89.24\% recall for face detection task and 98.63\% verification accuracy for face recognition task simultaneously, which are comparable to state-of-the-art results.
[ { "version": "v1", "created": "Fri, 31 Mar 2017 09:48:32 GMT" } ]
2017-04-03T00:00:00
[ [ "Chi", "Liying", "" ], [ "Zhang", "Hongxin", "" ], [ "Chen", "Mingxiu", "" ] ]
TITLE: End-To-End Face Detection and Recognition ABSTRACT: Plenty of face detection and recognition methods have been proposed and got delightful results in decades. Common face recognition pipeline consists of: 1) face detection, 2) face alignment, 3) feature extraction, 4) similarity calculation, which are separated and independent from each other. The separated face analyzing stages lead the model redundant calculation and are hard for end-to-end training. In this paper, we proposed a novel end-to-end trainable convolutional network framework for face detection and recognition, in which a geometric transformation matrix was directly learned to align the faces, instead of predicting the facial landmarks. In training stage, our single CNN model is supervised only by face bounding boxes and personal identities, which are publicly available from WIDER FACE \cite{Yang2016} dataset and CASIA-WebFace \cite{Yi2014} dataset. Tested on Face Detection Dataset and Benchmark (FDDB) \cite{Jain2010} dataset and Labeled Face in the Wild (LFW) \cite{Huang2007} dataset, we have achieved 89.24\% recall for face detection task and 98.63\% verification accuracy for face recognition task simultaneously, which are comparable to state-of-the-art results.
no_new_dataset
0.947624
1703.10889
Yudong Liang
Yudong Liang, Radu Timofte, Jinjun Wang, Yihong Gong and Nanning Zheng
Single Image Super Resolution - When Model Adaptation Matters
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the recent years impressive advances were made for single image super-resolution. Deep learning is behind a big part of this success. Deep(er) architecture design and external priors modeling are the key ingredients. The internal contents of the low resolution input image is neglected with deep modeling despite the earlier works showing the power of using such internal priors. In this paper we propose a novel deep convolutional neural network carefully designed for robustness and efficiency at both learning and testing. Moreover, we propose a couple of model adaptation strategies to the internal contents of the low resolution input image and analyze their strong points and weaknesses. By trading runtime and using internal priors we achieve 0.1 up to 0.3dB PSNR improvements over best reported results on standard datasets. Our adaptation especially favors images with repetitive structures or under large resolutions. Moreover, it can be combined with other simple techniques, such as back-projection or enhanced prediction, for further improvements.
[ { "version": "v1", "created": "Fri, 31 Mar 2017 13:20:19 GMT" } ]
2017-04-03T00:00:00
[ [ "Liang", "Yudong", "" ], [ "Timofte", "Radu", "" ], [ "Wang", "Jinjun", "" ], [ "Gong", "Yihong", "" ], [ "Zheng", "Nanning", "" ] ]
TITLE: Single Image Super Resolution - When Model Adaptation Matters ABSTRACT: In the recent years impressive advances were made for single image super-resolution. Deep learning is behind a big part of this success. Deep(er) architecture design and external priors modeling are the key ingredients. The internal contents of the low resolution input image is neglected with deep modeling despite the earlier works showing the power of using such internal priors. In this paper we propose a novel deep convolutional neural network carefully designed for robustness and efficiency at both learning and testing. Moreover, we propose a couple of model adaptation strategies to the internal contents of the low resolution input image and analyze their strong points and weaknesses. By trading runtime and using internal priors we achieve 0.1 up to 0.3dB PSNR improvements over best reported results on standard datasets. Our adaptation especially favors images with repetitive structures or under large resolutions. Moreover, it can be combined with other simple techniques, such as back-projection or enhanced prediction, for further improvements.
no_new_dataset
0.947186
1703.10898
Jie Song
Jie Song, Limin Wang, Luc Van Gool, Otmar Hilliges
Thin-Slicing Network: A Deep Structured Model for Pose Estimation in Videos
Preliminary version to appear in CVPR2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deep ConvNets have been shown to be effective for the task of human pose estimation from single images. However, several challenging issues arise in the video-based case such as self-occlusion, motion blur, and uncommon poses with few or no examples in training data sets. Temporal information can provide additional cues about the location of body joints and help to alleviate these issues. In this paper, we propose a deep structured model to estimate a sequence of human poses in unconstrained videos. This model can be efficiently trained in an end-to-end manner and is capable of representing appearance of body joints and their spatio-temporal relationships simultaneously. Domain knowledge about the human body is explicitly incorporated into the network providing effective priors to regularize the skeletal structure and to enforce temporal consistency. The proposed end-to-end architecture is evaluated on two widely used benchmarks (Penn Action dataset and JHMDB dataset) for video-based pose estimation. Our approach significantly outperforms the existing state-of-the-art methods.
[ { "version": "v1", "created": "Fri, 31 Mar 2017 13:59:31 GMT" } ]
2017-04-03T00:00:00
[ [ "Song", "Jie", "" ], [ "Wang", "Limin", "" ], [ "Van Gool", "Luc", "" ], [ "Hilliges", "Otmar", "" ] ]
TITLE: Thin-Slicing Network: A Deep Structured Model for Pose Estimation in Videos ABSTRACT: Deep ConvNets have been shown to be effective for the task of human pose estimation from single images. However, several challenging issues arise in the video-based case such as self-occlusion, motion blur, and uncommon poses with few or no examples in training data sets. Temporal information can provide additional cues about the location of body joints and help to alleviate these issues. In this paper, we propose a deep structured model to estimate a sequence of human poses in unconstrained videos. This model can be efficiently trained in an end-to-end manner and is capable of representing appearance of body joints and their spatio-temporal relationships simultaneously. Domain knowledge about the human body is explicitly incorporated into the network providing effective priors to regularize the skeletal structure and to enforce temporal consistency. The proposed end-to-end architecture is evaluated on two widely used benchmarks (Penn Action dataset and JHMDB dataset) for video-based pose estimation. Our approach significantly outperforms the existing state-of-the-art methods.
no_new_dataset
0.949669
1703.10901
Simion-Vlad Bogolin
Ioana Croitoru (1), Simion-Vlad Bogolin (1), Marius Leordeanu (1 and 2) ((1) Institute of Mathematics of the Romanian Academy, (2) University "Politehnica" of Bucharest)
Unsupervised learning from video to detect foreground objects in single images
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Unsupervised learning from visual data is one of the most difficult challenges in computer vision, being a fundamental task for understanding how visual recognition works. From a practical point of view, learning from unsupervised visual input has an immense practical value, as very large quantities of unlabeled videos can be collected at low cost. In this paper, we address the task of unsupervised learning to detect and segment foreground objects in single images. We achieve our goal by training a student pathway, consisting of a deep neural network. It learns to predict from a single input image (a video frame) the output for that particular frame, of a teacher pathway that performs unsupervised object discovery in video. Our approach is different from the published literature that performs unsupervised discovery in videos or in collections of images at test time. We move the unsupervised discovery phase during the training stage, while at test time we apply the standard feed-forward processing along the student pathway. This has a dual benefit: firstly, it allows in principle unlimited possibilities of learning and generalization during training, while remaining very fast at testing. Secondly, the student not only becomes able to detect in single images significantly better than its unsupervised video discovery teacher, but it also achieves state of the art results on two important current benchmarks, YouTube Objects and Object Discovery datasets. Moreover, at test time, our system is at least two orders of magnitude faster than other previous methods.
[ { "version": "v1", "created": "Fri, 31 Mar 2017 14:05:13 GMT" } ]
2017-04-03T00:00:00
[ [ "Croitoru", "Ioana", "", "1 and\n 2" ], [ "Bogolin", "Simion-Vlad", "", "1 and\n 2" ], [ "Leordeanu", "Marius", "", "1 and\n 2" ] ]
TITLE: Unsupervised learning from video to detect foreground objects in single images ABSTRACT: Unsupervised learning from visual data is one of the most difficult challenges in computer vision, being a fundamental task for understanding how visual recognition works. From a practical point of view, learning from unsupervised visual input has an immense practical value, as very large quantities of unlabeled videos can be collected at low cost. In this paper, we address the task of unsupervised learning to detect and segment foreground objects in single images. We achieve our goal by training a student pathway, consisting of a deep neural network. It learns to predict from a single input image (a video frame) the output for that particular frame, of a teacher pathway that performs unsupervised object discovery in video. Our approach is different from the published literature that performs unsupervised discovery in videos or in collections of images at test time. We move the unsupervised discovery phase during the training stage, while at test time we apply the standard feed-forward processing along the student pathway. This has a dual benefit: firstly, it allows in principle unlimited possibilities of learning and generalization during training, while remaining very fast at testing. Secondly, the student not only becomes able to detect in single images significantly better than its unsupervised video discovery teacher, but it also achieves state of the art results on two important current benchmarks, YouTube Objects and Object Discovery datasets. Moreover, at test time, our system is at least two orders of magnitude faster than other previous methods.
no_new_dataset
0.947039
1703.10902
Xiao Yang
Xiao Yang, Roland Kwitt, Martin Styner, Marc Niethammer
Fast Predictive Multimodal Image Registration
Accepted as a conference paper for ISBI 2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce a deep encoder-decoder architecture for image deformation prediction from multimodal images. Specifically, we design an image-patch-based deep network that jointly (i) learns an image similarity measure and (ii) the relationship between image patches and deformation parameters. While our method can be applied to general image registration formulations, we focus on the Large Deformation Diffeomorphic Metric Mapping (LDDMM) registration model. By predicting the initial momentum of the shooting formulation of LDDMM, we preserve its mathematical properties and drastically reduce the computation time, compared to optimization-based approaches. Furthermore, we create a Bayesian probabilistic version of the network that allows evaluation of registration uncertainty via sampling of the network at test time. We evaluate our method on a 3D brain MRI dataset using both T1- and T2-weighted images. Our experiments show that our method generates accurate predictions and that learning the similarity measure leads to more consistent registrations than relying on generic multimodal image similarity measures, such as mutual information. Our approach is an order of magnitude faster than optimization-based LDDMM.
[ { "version": "v1", "created": "Fri, 31 Mar 2017 14:05:57 GMT" } ]
2017-04-03T00:00:00
[ [ "Yang", "Xiao", "" ], [ "Kwitt", "Roland", "" ], [ "Styner", "Martin", "" ], [ "Niethammer", "Marc", "" ] ]
TITLE: Fast Predictive Multimodal Image Registration ABSTRACT: We introduce a deep encoder-decoder architecture for image deformation prediction from multimodal images. Specifically, we design an image-patch-based deep network that jointly (i) learns an image similarity measure and (ii) the relationship between image patches and deformation parameters. While our method can be applied to general image registration formulations, we focus on the Large Deformation Diffeomorphic Metric Mapping (LDDMM) registration model. By predicting the initial momentum of the shooting formulation of LDDMM, we preserve its mathematical properties and drastically reduce the computation time, compared to optimization-based approaches. Furthermore, we create a Bayesian probabilistic version of the network that allows evaluation of registration uncertainty via sampling of the network at test time. We evaluate our method on a 3D brain MRI dataset using both T1- and T2-weighted images. Our experiments show that our method generates accurate predictions and that learning the similarity measure leads to more consistent registrations than relying on generic multimodal image similarity measures, such as mutual information. Our approach is an order of magnitude faster than optimization-based LDDMM.
no_new_dataset
0.950134
1703.11004
Daiki Matsumoto
Daiki Matsumoto, Thomas Indinger
On-the-fly algorithm for Dynamic Mode Decomposition using Incremental Singular Value Decomposition and Total Least Squares
null
null
null
null
physics.flu-dyn
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dynamic Mode Decomposition (DMD) is a useful tool to effectively extract the dominant dynamic flow structure from a unsteady flow field. However, DMD requires massive computational resources with respect to memory consumption and the usage of storage. In this paper, an alternative incremental algorithm of Total DMD (Incremental TDMD) is proposed which is based on Incremental Singular Value Decomposition (SVD). The advantage of Incremental TDMD compared to the existing on-the-fly algorithms of DMD is that Sparsity-Promoting DMD (SPDMD) can be performed after the incremental process without saving huge datasets on the disk space. SPDMD combined with Incremental TDMD enable the effective identification of dominant modes which are relevant to the results from conventional TDMD combined with SPDMD.
[ { "version": "v1", "created": "Fri, 31 Mar 2017 17:47:11 GMT" } ]
2017-04-03T00:00:00
[ [ "Matsumoto", "Daiki", "" ], [ "Indinger", "Thomas", "" ] ]
TITLE: On-the-fly algorithm for Dynamic Mode Decomposition using Incremental Singular Value Decomposition and Total Least Squares ABSTRACT: Dynamic Mode Decomposition (DMD) is a useful tool to effectively extract the dominant dynamic flow structure from a unsteady flow field. However, DMD requires massive computational resources with respect to memory consumption and the usage of storage. In this paper, an alternative incremental algorithm of Total DMD (Incremental TDMD) is proposed which is based on Incremental Singular Value Decomposition (SVD). The advantage of Incremental TDMD compared to the existing on-the-fly algorithms of DMD is that Sparsity-Promoting DMD (SPDMD) can be performed after the incremental process without saving huge datasets on the disk space. SPDMD combined with Incremental TDMD enable the effective identification of dominant modes which are relevant to the results from conventional TDMD combined with SPDMD.
no_new_dataset
0.948442
1609.00988
Nhien-An Le-Khac
Nhien-An Le-Khac, Martin Bue, Michael Whelan, Tahar Kechadi
A clustering-based data reduction for very large spatio-temporal datasets
null
null
null
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Today, huge amounts of data are being collected with spatial and temporal components from sources such as meteorological, satellite imagery etc. Efficient visualisation as well as discovery of useful knowledge from these datasets is therefore very challenging and becoming a massive economic need. Data Mining has emerged as the technology to discover hidden knowledge in very large amounts of data. Furthermore, data mining techniques could be applied to decrease the large size of raw data by retrieving its useful knowledge as representatives. As a consequence, instead of dealing with a large size of raw data, we can use these representatives to visualise or to analyse without losing important information. This paper presents a new approach based on different clustering techniques for data reduction to help analyse very large spatio-temporal data. We also present and discuss preliminary results of this approach.
[ { "version": "v1", "created": "Sun, 4 Sep 2016 20:35:18 GMT" }, { "version": "v2", "created": "Wed, 29 Mar 2017 18:55:18 GMT" } ]
2017-03-31T00:00:00
[ [ "Le-Khac", "Nhien-An", "" ], [ "Bue", "Martin", "" ], [ "Whelan", "Michael", "" ], [ "Kechadi", "Tahar", "" ] ]
TITLE: A clustering-based data reduction for very large spatio-temporal datasets ABSTRACT: Today, huge amounts of data are being collected with spatial and temporal components from sources such as meteorological, satellite imagery etc. Efficient visualisation as well as discovery of useful knowledge from these datasets is therefore very challenging and becoming a massive economic need. Data Mining has emerged as the technology to discover hidden knowledge in very large amounts of data. Furthermore, data mining techniques could be applied to decrease the large size of raw data by retrieving its useful knowledge as representatives. As a consequence, instead of dealing with a large size of raw data, we can use these representatives to visualise or to analyse without losing important information. This paper presents a new approach based on different clustering techniques for data reduction to help analyse very large spatio-temporal data. We also present and discuss preliminary results of this approach.
no_new_dataset
0.951684
1702.05729
Shuang Li
Shuang Li, Tong Xiao, Hongsheng Li, Bolei Zhou, Dayu Yue, Xiaogang Wang
Person Search with Natural Language Description
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Searching persons in large-scale image databases with the query of natural language description has important applications in video surveillance. Existing methods mainly focused on searching persons with image-based or attribute-based queries, which have major limitations for a practical usage. In this paper, we study the problem of person search with natural language description. Given the textual description of a person, the algorithm of the person search is required to rank all the samples in the person database then retrieve the most relevant sample corresponding to the queried description. Since there is no person dataset or benchmark with textual description available, we collect a large-scale person description dataset with detailed natural language annotations and person samples from various sources, termed as CUHK Person Description Dataset (CUHK-PEDES). A wide range of possible models and baselines have been evaluated and compared on the person search benchmark. An Recurrent Neural Network with Gated Neural Attention mechanism (GNA-RNN) is proposed to establish the state-of-the art performance on person search.
[ { "version": "v1", "created": "Sun, 19 Feb 2017 10:01:33 GMT" }, { "version": "v2", "created": "Thu, 30 Mar 2017 07:51:10 GMT" } ]
2017-03-31T00:00:00
[ [ "Li", "Shuang", "" ], [ "Xiao", "Tong", "" ], [ "Li", "Hongsheng", "" ], [ "Zhou", "Bolei", "" ], [ "Yue", "Dayu", "" ], [ "Wang", "Xiaogang", "" ] ]
TITLE: Person Search with Natural Language Description ABSTRACT: Searching persons in large-scale image databases with the query of natural language description has important applications in video surveillance. Existing methods mainly focused on searching persons with image-based or attribute-based queries, which have major limitations for a practical usage. In this paper, we study the problem of person search with natural language description. Given the textual description of a person, the algorithm of the person search is required to rank all the samples in the person database then retrieve the most relevant sample corresponding to the queried description. Since there is no person dataset or benchmark with textual description available, we collect a large-scale person description dataset with detailed natural language annotations and person samples from various sources, termed as CUHK Person Description Dataset (CUHK-PEDES). A wide range of possible models and baselines have been evaluated and compared on the person search benchmark. An Recurrent Neural Network with Gated Neural Attention mechanism (GNA-RNN) is proposed to establish the state-of-the art performance on person search.
new_dataset
0.955026
1703.08544
Joshua Michalenko
Joshua J. Michalenko, Andrew S. Lan, Richard G. Baraniuk
Data-Mining Textual Responses to Uncover Misconception Patterns
7 Pages, Submitted to EDM 2017, Workshop version accepted to L@S 2017. Article title and acronym changed to more clearly indicate the scientific goal of the paper of improving the quality of educational instruction
null
null
null
stat.ML cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An important, yet largely unstudied, problem in student data analysis is to detect misconceptions from students' responses to open-response questions. Misconception detection enables instructors to deliver more targeted feedback on the misconceptions exhibited by many students in their class, thus improving the quality of instruction. In this paper, we propose a new natural language processing-based framework to detect the common misconceptions among students' textual responses to short-answer questions. We propose a probabilistic model for students' textual responses involving misconceptions and experimentally validate it on a real-world student-response dataset. Experimental results show that our proposed framework excels at classifying whether a response exhibits one or more misconceptions. More importantly, it can also automatically detect the common misconceptions exhibited across responses from multiple students to multiple questions; this property is especially important at large scale, since instructors will no longer need to manually specify all possible misconceptions that students might exhibit.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 14:49:58 GMT" }, { "version": "v2", "created": "Thu, 30 Mar 2017 02:50:33 GMT" } ]
2017-03-31T00:00:00
[ [ "Michalenko", "Joshua J.", "" ], [ "Lan", "Andrew S.", "" ], [ "Baraniuk", "Richard G.", "" ] ]
TITLE: Data-Mining Textual Responses to Uncover Misconception Patterns ABSTRACT: An important, yet largely unstudied, problem in student data analysis is to detect misconceptions from students' responses to open-response questions. Misconception detection enables instructors to deliver more targeted feedback on the misconceptions exhibited by many students in their class, thus improving the quality of instruction. In this paper, we propose a new natural language processing-based framework to detect the common misconceptions among students' textual responses to short-answer questions. We propose a probabilistic model for students' textual responses involving misconceptions and experimentally validate it on a real-world student-response dataset. Experimental results show that our proposed framework excels at classifying whether a response exhibits one or more misconceptions. More importantly, it can also automatically detect the common misconceptions exhibited across responses from multiple students to multiple questions; this property is especially important at large scale, since instructors will no longer need to manually specify all possible misconceptions that students might exhibit.
no_new_dataset
0.954137
1703.10196
Edward Boyda
Edward Boyda, Colin McCormick, and Dan Hammer
Detecting Human Interventions on the Landscape: KAZE Features, Poisson Point Processes, and a Construction Dataset
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present an algorithm capable of identifying a wide variety of human-induced change on the surface of the planet by analyzing matches between local features in time-sequenced remote sensing imagery. We evaluate feature sets, match protocols, and the statistical modeling of feature matches. With application of KAZE features, k-nearest-neighbor descriptor matching, and geometric proximity and bi-directional match consistency checks, average match rates increase more than two-fold over the previous standard. In testing our platform, we developed a small, labeled benchmark dataset expressing large-scale residential, industrial, and civic construction, along with null instances, in California between the years 2010 and 2012. On the benchmark set, our algorithm makes precise, accurate change proposals on two-thirds of scenes. Further, the detection threshold can be tuned so that all or almost all proposed detections are true positives.
[ { "version": "v1", "created": "Wed, 29 Mar 2017 18:56:32 GMT" } ]
2017-03-31T00:00:00
[ [ "Boyda", "Edward", "" ], [ "McCormick", "Colin", "" ], [ "Hammer", "Dan", "" ] ]
TITLE: Detecting Human Interventions on the Landscape: KAZE Features, Poisson Point Processes, and a Construction Dataset ABSTRACT: We present an algorithm capable of identifying a wide variety of human-induced change on the surface of the planet by analyzing matches between local features in time-sequenced remote sensing imagery. We evaluate feature sets, match protocols, and the statistical modeling of feature matches. With application of KAZE features, k-nearest-neighbor descriptor matching, and geometric proximity and bi-directional match consistency checks, average match rates increase more than two-fold over the previous standard. In testing our platform, we developed a small, labeled benchmark dataset expressing large-scale residential, industrial, and civic construction, along with null instances, in California between the years 2010 and 2012. On the benchmark set, our algorithm makes precise, accurate change proposals on two-thirds of scenes. Further, the detection threshold can be tuned so that all or almost all proposed detections are true positives.
new_dataset
0.951953
1703.10304
Lei Fan
Lei Fan, Ziyu Pan, Long Chen and Kai Huang
Planecell: Representing the 3D Space with Planes
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Reconstruction based on the stereo camera has received considerable attention recently, but two particular challenges still remain. The first concerns the need to aggregate similar pixels in an effective approach, and the second is to maintain as much of the available information as possible while ensuring sufficient accuracy. To overcome these issues, we propose a new 3D representation method, namely, planecell, that extracts planarity from the depth-assisted image segmentation and then projects these depth planes into the 3D world. An energy function formulated from Conditional Random Field that generalizes the planar relationships is maximized to merge coplanar segments. We evaluate our method with a variety of reconstruction baselines on both KITTI and Middlebury datasets, and the results indicate the superiorities compared to other 3D space representation methods in accuracy, memory requirements and further applications.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 03:58:05 GMT" } ]
2017-03-31T00:00:00
[ [ "Fan", "Lei", "" ], [ "Pan", "Ziyu", "" ], [ "Chen", "Long", "" ], [ "Huang", "Kai", "" ] ]
TITLE: Planecell: Representing the 3D Space with Planes ABSTRACT: Reconstruction based on the stereo camera has received considerable attention recently, but two particular challenges still remain. The first concerns the need to aggregate similar pixels in an effective approach, and the second is to maintain as much of the available information as possible while ensuring sufficient accuracy. To overcome these issues, we propose a new 3D representation method, namely, planecell, that extracts planarity from the depth-assisted image segmentation and then projects these depth planes into the 3D world. An energy function formulated from Conditional Random Field that generalizes the planar relationships is maximized to merge coplanar segments. We evaluate our method with a variety of reconstruction baselines on both KITTI and Middlebury datasets, and the results indicate the superiorities compared to other 3D space representation methods in accuracy, memory requirements and further applications.
no_new_dataset
0.955026
1703.10345
Besnik Fetahu
Besnik Fetahu and Abhijit Anand and Avishek Anand
How much is Wikipedia Lagging Behind News?
null
null
10.1145/2786451.2786460
null
cs.IR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Wikipedia, rich in entities and events, is an invaluable resource for various knowledge harvesting, extraction and mining tasks. Numerous resources like DBpedia, YAGO and other knowledge bases are based on extracting entity and event based knowledge from it. Online news, on the other hand, is an authoritative and rich source for emerging entities, events and facts relating to existing entities. In this work, we study the creation of entities in Wikipedia with respect to news by studying how entity and event based information flows from news to Wikipedia. We analyze the lag of Wikipedia (based on the revision history of the English Wikipedia) with 20 years of \emph{The New York Times} dataset (NYT). We model and analyze the lag of entities and events, namely their first appearance in Wikipedia and in NYT, respectively. In our extensive experimental analysis, we find that almost 20\% of the external references in entity pages are news articles encoding the importance of news to Wikipedia. Second, we observe that the entity-based lag follows a normal distribution with a high standard deviation, whereas the lag for news-based events is typically very low. Finally, we find that events are responsible for creation of emergent entities with as many as 12\% of the entities mentioned in the event page are created after the creation of the event page.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 08:05:17 GMT" } ]
2017-03-31T00:00:00
[ [ "Fetahu", "Besnik", "" ], [ "Anand", "Abhijit", "" ], [ "Anand", "Avishek", "" ] ]
TITLE: How much is Wikipedia Lagging Behind News? ABSTRACT: Wikipedia, rich in entities and events, is an invaluable resource for various knowledge harvesting, extraction and mining tasks. Numerous resources like DBpedia, YAGO and other knowledge bases are based on extracting entity and event based knowledge from it. Online news, on the other hand, is an authoritative and rich source for emerging entities, events and facts relating to existing entities. In this work, we study the creation of entities in Wikipedia with respect to news by studying how entity and event based information flows from news to Wikipedia. We analyze the lag of Wikipedia (based on the revision history of the English Wikipedia) with 20 years of \emph{The New York Times} dataset (NYT). We model and analyze the lag of entities and events, namely their first appearance in Wikipedia and in NYT, respectively. In our extensive experimental analysis, we find that almost 20\% of the external references in entity pages are news articles encoding the importance of news to Wikipedia. Second, we observe that the entity-based lag follows a normal distribution with a high standard deviation, whereas the lag for news-based events is typically very low. Finally, we find that events are responsible for creation of emergent entities with as many as 12\% of the entities mentioned in the event page are created after the creation of the event page.
no_new_dataset
0.941654
1703.10349
Besnik Fetahu
Besnik Fetahu and Ujwal Gadiraju and Stefan Dietze
Improving Entity Retrieval on Structured Data
null
null
10.1007/978-3-319-25007-6_28
null
cs.IR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The increasing amount of data on the Web, in particular of Linked Data, has led to a diverse landscape of datasets, which make entity retrieval a challenging task. Explicit cross-dataset links, for instance to indicate co-references or related entities can significantly improve entity retrieval. However, only a small fraction of entities are interlinked through explicit statements. In this paper, we propose a two-fold entity retrieval approach. In a first, offline preprocessing step, we cluster entities based on the \emph{x--means} and \emph{spectral} clustering algorithms. In the second step, we propose an optimized retrieval model which takes advantage of our precomputed clusters. For a given set of entities retrieved by the BM25F retrieval approach and a given user query, we further expand the result set with relevant entities by considering features of the queries, entities and the precomputed clusters. Finally, we re-rank the expanded result set with respect to the relevance to the query. We perform a thorough experimental evaluation on the Billions Triple Challenge (BTC12) dataset. The proposed approach shows significant improvements compared to the baseline and state of the art approaches.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 08:25:35 GMT" } ]
2017-03-31T00:00:00
[ [ "Fetahu", "Besnik", "" ], [ "Gadiraju", "Ujwal", "" ], [ "Dietze", "Stefan", "" ] ]
TITLE: Improving Entity Retrieval on Structured Data ABSTRACT: The increasing amount of data on the Web, in particular of Linked Data, has led to a diverse landscape of datasets, which make entity retrieval a challenging task. Explicit cross-dataset links, for instance to indicate co-references or related entities can significantly improve entity retrieval. However, only a small fraction of entities are interlinked through explicit statements. In this paper, we propose a two-fold entity retrieval approach. In a first, offline preprocessing step, we cluster entities based on the \emph{x--means} and \emph{spectral} clustering algorithms. In the second step, we propose an optimized retrieval model which takes advantage of our precomputed clusters. For a given set of entities retrieved by the BM25F retrieval approach and a given user query, we further expand the result set with relevant entities by considering features of the queries, entities and the precomputed clusters. Finally, we re-rank the expanded result set with respect to the relevance to the query. We perform a thorough experimental evaluation on the Billions Triple Challenge (BTC12) dataset. The proposed approach shows significant improvements compared to the baseline and state of the art approaches.
no_new_dataset
0.945601
1703.10603
Joseph Gomes
Joseph Gomes, Bharath Ramsundar, Evan N. Feinberg, Vijay S. Pande
Atomic Convolutional Networks for Predicting Protein-Ligand Binding Affinity
null
null
null
null
cs.LG physics.chem-ph stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Empirical scoring functions based on either molecular force fields or cheminformatics descriptors are widely used, in conjunction with molecular docking, during the early stages of drug discovery to predict potency and binding affinity of a drug-like molecule to a given target. These models require expert-level knowledge of physical chemistry and biology to be encoded as hand-tuned parameters or features rather than allowing the underlying model to select features in a data-driven procedure. Here, we develop a general 3-dimensional spatial convolution operation for learning atomic-level chemical interactions directly from atomic coordinates and demonstrate its application to structure-based bioactivity prediction. The atomic convolutional neural network is trained to predict the experimentally determined binding affinity of a protein-ligand complex by direct calculation of the energy associated with the complex, protein, and ligand given the crystal structure of the binding pose. Non-covalent interactions present in the complex that are absent in the protein-ligand sub-structures are identified and the model learns the interaction strength associated with these features. We test our model by predicting the binding free energy of a subset of protein-ligand complexes found in the PDBBind dataset and compare with state-of-the-art cheminformatics and machine learning-based approaches. We find that all methods achieve experimental accuracy and that atomic convolutional networks either outperform or perform competitively with the cheminformatics based methods. Unlike all previous protein-ligand prediction systems, atomic convolutional networks are end-to-end and fully-differentiable. They represent a new data-driven, physics-based deep learning model paradigm that offers a strong foundation for future improvements in structure-based bioactivity prediction.
[ { "version": "v1", "created": "Thu, 30 Mar 2017 17:58:31 GMT" } ]
2017-03-31T00:00:00
[ [ "Gomes", "Joseph", "" ], [ "Ramsundar", "Bharath", "" ], [ "Feinberg", "Evan N.", "" ], [ "Pande", "Vijay S.", "" ] ]
TITLE: Atomic Convolutional Networks for Predicting Protein-Ligand Binding Affinity ABSTRACT: Empirical scoring functions based on either molecular force fields or cheminformatics descriptors are widely used, in conjunction with molecular docking, during the early stages of drug discovery to predict potency and binding affinity of a drug-like molecule to a given target. These models require expert-level knowledge of physical chemistry and biology to be encoded as hand-tuned parameters or features rather than allowing the underlying model to select features in a data-driven procedure. Here, we develop a general 3-dimensional spatial convolution operation for learning atomic-level chemical interactions directly from atomic coordinates and demonstrate its application to structure-based bioactivity prediction. The atomic convolutional neural network is trained to predict the experimentally determined binding affinity of a protein-ligand complex by direct calculation of the energy associated with the complex, protein, and ligand given the crystal structure of the binding pose. Non-covalent interactions present in the complex that are absent in the protein-ligand sub-structures are identified and the model learns the interaction strength associated with these features. We test our model by predicting the binding free energy of a subset of protein-ligand complexes found in the PDBBind dataset and compare with state-of-the-art cheminformatics and machine learning-based approaches. We find that all methods achieve experimental accuracy and that atomic convolutional networks either outperform or perform competitively with the cheminformatics based methods. Unlike all previous protein-ligand prediction systems, atomic convolutional networks are end-to-end and fully-differentiable. They represent a new data-driven, physics-based deep learning model paradigm that offers a strong foundation for future improvements in structure-based bioactivity prediction.
no_new_dataset
0.953794
1607.07129
Yuan Gao
Yuan Gao and Alan L. Yuille
Exploiting Symmetry and/or Manhattan Properties for 3D Object Structure Estimation from Single and Multiple Images
Accepted to CVPR 2017
null
null
null
cs.CV cs.CG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many man-made objects have intrinsic symmetries and Manhattan structure. By assuming an orthographic projection model, this paper addresses the estimation of 3D structures and camera projection using symmetry and/or Manhattan structure cues, which occur when the input is single- or multiple-image from the same category, e.g., multiple different cars. Specifically, analysis on the single image case implies that Manhattan alone is sufficient to recover the camera projection, and then the 3D structure can be reconstructed uniquely exploiting symmetry. However, Manhattan structure can be difficult to observe from a single image due to occlusion. To this end, we extend to the multiple-image case which can also exploit symmetry but does not require Manhattan axes. We propose a novel rigid structure from motion method, exploiting symmetry and using multiple images from the same category as input. Experimental results on the Pascal3D+ dataset show that our method significantly outperforms baseline methods.
[ { "version": "v1", "created": "Mon, 25 Jul 2016 02:36:51 GMT" }, { "version": "v2", "created": "Sat, 19 Nov 2016 19:28:56 GMT" }, { "version": "v3", "created": "Wed, 29 Mar 2017 08:15:16 GMT" } ]
2017-03-30T00:00:00
[ [ "Gao", "Yuan", "" ], [ "Yuille", "Alan L.", "" ] ]
TITLE: Exploiting Symmetry and/or Manhattan Properties for 3D Object Structure Estimation from Single and Multiple Images ABSTRACT: Many man-made objects have intrinsic symmetries and Manhattan structure. By assuming an orthographic projection model, this paper addresses the estimation of 3D structures and camera projection using symmetry and/or Manhattan structure cues, which occur when the input is single- or multiple-image from the same category, e.g., multiple different cars. Specifically, analysis on the single image case implies that Manhattan alone is sufficient to recover the camera projection, and then the 3D structure can be reconstructed uniquely exploiting symmetry. However, Manhattan structure can be difficult to observe from a single image due to occlusion. To this end, we extend to the multiple-image case which can also exploit symmetry but does not require Manhattan axes. We propose a novel rigid structure from motion method, exploiting symmetry and using multiple images from the same category as input. Experimental results on the Pascal3D+ dataset show that our method significantly outperforms baseline methods.
no_new_dataset
0.955486
1609.02031
Nhien-An Le-Khac
Nhien-An Le-Khac, Sammer Markos, Michael O'Neill, Anthony Brabazon and Tahar Kechadi
An efficient Search Tool for an Anti-Money Laundering Application of an Multi-national Bank's Dataset
null
null
null
null
cs.DB cs.CE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Today, money laundering (ML) poses a serious threat not only to financial institutions but also to the nations. This criminal activity is becoming more and more sophisticated and seems to have moved from the clichy of drug trafficking to financing terrorism and surely not forgetting personal gain. Most of the financial institutions internationally have been implementing anti-money laundering solutions (AML) to fight investment fraud activities. In AML, the customer identification is an important task which helps AML experts to monitor customer habits: some being customer domicile, transactions that they are involved in etc. However, simple query tools provided by current DBMS as well as naive approaches in customer searching may produce incorrect and ambiguous results and their processing time is also very high due to the complexity of the database system architecture. In this paper, we present a new approach for identifying customers registered in an investment bank. This approach is developed as a tool that allows AML experts to quickly identify customers who are managed independently across separate databases. It is tested on real-world datasets, which are real and large financial datasets. Some preliminary experimental results show that this new approach is efficient and effective.
[ { "version": "v1", "created": "Sun, 4 Sep 2016 20:17:45 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 21:30:08 GMT" } ]
2017-03-30T00:00:00
[ [ "Le-Khac", "Nhien-An", "" ], [ "Markos", "Sammer", "" ], [ "O'Neill", "Michael", "" ], [ "Brabazon", "Anthony", "" ], [ "Kechadi", "Tahar", "" ] ]
TITLE: An efficient Search Tool for an Anti-Money Laundering Application of an Multi-national Bank's Dataset ABSTRACT: Today, money laundering (ML) poses a serious threat not only to financial institutions but also to the nations. This criminal activity is becoming more and more sophisticated and seems to have moved from the clichy of drug trafficking to financing terrorism and surely not forgetting personal gain. Most of the financial institutions internationally have been implementing anti-money laundering solutions (AML) to fight investment fraud activities. In AML, the customer identification is an important task which helps AML experts to monitor customer habits: some being customer domicile, transactions that they are involved in etc. However, simple query tools provided by current DBMS as well as naive approaches in customer searching may produce incorrect and ambiguous results and their processing time is also very high due to the complexity of the database system architecture. In this paper, we present a new approach for identifying customers registered in an investment bank. This approach is developed as a tool that allows AML experts to quickly identify customers who are managed independently across separate databases. It is tested on real-world datasets, which are real and large financial datasets. Some preliminary experimental results show that this new approach is efficient and effective.
no_new_dataset
0.947962
1611.08002
Zhe Gan
Zhe Gan, Chuang Gan, Xiaodong He, Yunchen Pu, Kenneth Tran, Jianfeng Gao, Lawrence Carin, Li Deng
Semantic Compositional Networks for Visual Captioning
Accepted in CVPR 2017
null
null
null
cs.CV cs.CL cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A Semantic Compositional Network (SCN) is developed for image captioning, in which semantic concepts (i.e., tags) are detected from the image, and the probability of each tag is used to compose the parameters in a long short-term memory (LSTM) network. The SCN extends each weight matrix of the LSTM to an ensemble of tag-dependent weight matrices. The degree to which each member of the ensemble is used to generate an image caption is tied to the image-dependent probability of the corresponding tag. In addition to captioning images, we also extend the SCN to generate captions for video clips. We qualitatively analyze semantic composition in SCNs, and quantitatively evaluate the algorithm on three benchmark datasets: COCO, Flickr30k, and Youtube2Text. Experimental results show that the proposed method significantly outperforms prior state-of-the-art approaches, across multiple evaluation metrics.
[ { "version": "v1", "created": "Wed, 23 Nov 2016 21:22:22 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 18:33:51 GMT" } ]
2017-03-30T00:00:00
[ [ "Gan", "Zhe", "" ], [ "Gan", "Chuang", "" ], [ "He", "Xiaodong", "" ], [ "Pu", "Yunchen", "" ], [ "Tran", "Kenneth", "" ], [ "Gao", "Jianfeng", "" ], [ "Carin", "Lawrence", "" ], [ "Deng", "Li", "" ] ]
TITLE: Semantic Compositional Networks for Visual Captioning ABSTRACT: A Semantic Compositional Network (SCN) is developed for image captioning, in which semantic concepts (i.e., tags) are detected from the image, and the probability of each tag is used to compose the parameters in a long short-term memory (LSTM) network. The SCN extends each weight matrix of the LSTM to an ensemble of tag-dependent weight matrices. The degree to which each member of the ensemble is used to generate an image caption is tied to the image-dependent probability of the corresponding tag. In addition to captioning images, we also extend the SCN to generate captions for video clips. We qualitatively analyze semantic composition in SCNs, and quantitatively evaluate the algorithm on three benchmark datasets: COCO, Flickr30k, and Youtube2Text. Experimental results show that the proposed method significantly outperforms prior state-of-the-art approaches, across multiple evaluation metrics.
no_new_dataset
0.951729
1612.08712
Aaditya Prakash
Aaditya Prakash, Nick Moran, Solomon Garber, Antonella DiLillo and James Storer
Semantic Perceptual Image Compression using Deep Convolution Networks
Accepted to Data Compression Conference, 11 pages, 5 figures
null
null
null
cs.MM cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It has long been considered a significant problem to improve the visual quality of lossy image and video compression. Recent advances in computing power together with the availability of large training data sets has increased interest in the application of deep learning cnns to address image recognition and image processing tasks. Here, we present a powerful cnn tailored to the specific task of semantic image understanding to achieve higher visual quality in lossy compression. A modest increase in complexity is incorporated to the encoder which allows a standard, off-the-shelf jpeg decoder to be used. While jpeg encoding may be optimized for generic images, the process is ultimately unaware of the specific content of the image to be compressed. Our technique makes jpeg content-aware by designing and training a model to identify multiple semantic regions in a given image. Unlike object detection techniques, our model does not require labeling of object positions and is able to identify objects in a single pass. We present a new cnn architecture directed specifically to image compression, which generates a map that highlights semantically-salient regions so that they can be encoded at higher quality as compared to background regions. By adding a complete set of features for every class, and then taking a threshold over the sum of all feature activations, we generate a map that highlights semantically-salient regions so that they can be encoded at a better quality compared to background regions. Experiments are presented on the Kodak PhotoCD dataset and the MIT Saliency Benchmark dataset, in which our algorithm achieves higher visual quality for the same compressed size.
[ { "version": "v1", "created": "Tue, 27 Dec 2016 19:21:18 GMT" }, { "version": "v2", "created": "Wed, 29 Mar 2017 16:29:54 GMT" } ]
2017-03-30T00:00:00
[ [ "Prakash", "Aaditya", "" ], [ "Moran", "Nick", "" ], [ "Garber", "Solomon", "" ], [ "DiLillo", "Antonella", "" ], [ "Storer", "James", "" ] ]
TITLE: Semantic Perceptual Image Compression using Deep Convolution Networks ABSTRACT: It has long been considered a significant problem to improve the visual quality of lossy image and video compression. Recent advances in computing power together with the availability of large training data sets has increased interest in the application of deep learning cnns to address image recognition and image processing tasks. Here, we present a powerful cnn tailored to the specific task of semantic image understanding to achieve higher visual quality in lossy compression. A modest increase in complexity is incorporated to the encoder which allows a standard, off-the-shelf jpeg decoder to be used. While jpeg encoding may be optimized for generic images, the process is ultimately unaware of the specific content of the image to be compressed. Our technique makes jpeg content-aware by designing and training a model to identify multiple semantic regions in a given image. Unlike object detection techniques, our model does not require labeling of object positions and is able to identify objects in a single pass. We present a new cnn architecture directed specifically to image compression, which generates a map that highlights semantically-salient regions so that they can be encoded at higher quality as compared to background regions. By adding a complete set of features for every class, and then taking a threshold over the sum of all feature activations, we generate a map that highlights semantically-salient regions so that they can be encoded at a better quality compared to background regions. Experiments are presented on the Kodak PhotoCD dataset and the MIT Saliency Benchmark dataset, in which our algorithm achieves higher visual quality for the same compressed size.
no_new_dataset
0.948489
1703.05468
Yongjoo Park
Yongjoo Park, Ahmad Shahab Tajik, Michael Cafarella, Barzan Mozafari
Database Learning: Toward a Database that Becomes Smarter Every Time
This manuscript is an extended report of the work published in ACM SIGMOD conference 2017
null
10.1145/3035918.3064013
null
cs.DB cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In today's databases, previous query answers rarely benefit answering future queries. For the first time, to the best of our knowledge, we change this paradigm in an approximate query processing (AQP) context. We make the following observation: the answer to each query reveals some degree of knowledge about the answer to another query because their answers stem from the same underlying distribution that has produced the entire dataset. Exploiting and refining this knowledge should allow us to answer queries more analytically, rather than by reading enormous amounts of raw data. Also, processing more queries should continuously enhance our knowledge of the underlying distribution, and hence lead to increasingly faster response times for future queries. We call this novel idea---learning from past query answers---Database Learning. We exploit the principle of maximum entropy to produce answers, which are in expectation guaranteed to be more accurate than existing sample-based approximations. Empowered by this idea, we build a query engine on top of Spark SQL, called Verdict. We conduct extensive experiments on real-world query traces from a large customer of a major database vendor. Our results demonstrate that Verdict supports 73.7% of these queries, speeding them up by up to 23.0x for the same accuracy level compared to existing AQP systems.
[ { "version": "v1", "created": "Thu, 16 Mar 2017 03:36:28 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 21:47:25 GMT" } ]
2017-03-30T00:00:00
[ [ "Park", "Yongjoo", "" ], [ "Tajik", "Ahmad Shahab", "" ], [ "Cafarella", "Michael", "" ], [ "Mozafari", "Barzan", "" ] ]
TITLE: Database Learning: Toward a Database that Becomes Smarter Every Time ABSTRACT: In today's databases, previous query answers rarely benefit answering future queries. For the first time, to the best of our knowledge, we change this paradigm in an approximate query processing (AQP) context. We make the following observation: the answer to each query reveals some degree of knowledge about the answer to another query because their answers stem from the same underlying distribution that has produced the entire dataset. Exploiting and refining this knowledge should allow us to answer queries more analytically, rather than by reading enormous amounts of raw data. Also, processing more queries should continuously enhance our knowledge of the underlying distribution, and hence lead to increasingly faster response times for future queries. We call this novel idea---learning from past query answers---Database Learning. We exploit the principle of maximum entropy to produce answers, which are in expectation guaranteed to be more accurate than existing sample-based approximations. Empowered by this idea, we build a query engine on top of Spark SQL, called Verdict. We conduct extensive experiments on real-world query traces from a large customer of a major database vendor. Our results demonstrate that Verdict supports 73.7% of these queries, speeding them up by up to 23.0x for the same accuracy level compared to existing AQP systems.
no_new_dataset
0.945851
1703.09752
Nhien-An Le-Khac
Loic Bontemps, Van Loi Cao, James McDermott, Nhien-An Le-Khac
Collective Anomaly Detection based on Long Short Term Memory Recurrent Neural Network
null
null
null
null
cs.LG cs.CR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Intrusion detection for computer network systems becomes one of the most critical tasks for network administrators today. It has an important role for organizations, governments and our society due to its valuable resources on computer networks. Traditional misuse detection strategies are unable to detect new and unknown intrusion. Besides, anomaly detection in network security is aim to distinguish between illegal or malicious events and normal behavior of network systems. Anomaly detection can be considered as a classification problem where it builds models of normal network behavior, which it uses to detect new patterns that significantly deviate from the model. Most of the cur- rent research on anomaly detection is based on the learning of normally and anomaly behaviors. They do not take into account the previous, re- cent events to detect the new incoming one. In this paper, we propose a real time collective anomaly detection model based on neural network learning and feature operating. Normally a Long Short Term Memory Recurrent Neural Network (LSTM RNN) is trained only on normal data and it is capable of predicting several time steps ahead of an input. In our approach, a LSTM RNN is trained with normal time series data before performing a live prediction for each time step. Instead of considering each time step separately, the observation of prediction errors from a certain number of time steps is now proposed as a new idea for detecting collective anomalies. The prediction errors from a number of the latest time steps above a threshold will indicate a collective anomaly. The model is built on a time series version of the KDD 1999 dataset. The experiments demonstrate that it is possible to offer reliable and efficient for collective anomaly detection.
[ { "version": "v1", "created": "Tue, 28 Mar 2017 19:04:11 GMT" } ]
2017-03-30T00:00:00
[ [ "Bontemps", "Loic", "" ], [ "Cao", "Van Loi", "" ], [ "McDermott", "James", "" ], [ "Le-Khac", "Nhien-An", "" ] ]
TITLE: Collective Anomaly Detection based on Long Short Term Memory Recurrent Neural Network ABSTRACT: Intrusion detection for computer network systems becomes one of the most critical tasks for network administrators today. It has an important role for organizations, governments and our society due to its valuable resources on computer networks. Traditional misuse detection strategies are unable to detect new and unknown intrusion. Besides, anomaly detection in network security is aim to distinguish between illegal or malicious events and normal behavior of network systems. Anomaly detection can be considered as a classification problem where it builds models of normal network behavior, which it uses to detect new patterns that significantly deviate from the model. Most of the cur- rent research on anomaly detection is based on the learning of normally and anomaly behaviors. They do not take into account the previous, re- cent events to detect the new incoming one. In this paper, we propose a real time collective anomaly detection model based on neural network learning and feature operating. Normally a Long Short Term Memory Recurrent Neural Network (LSTM RNN) is trained only on normal data and it is capable of predicting several time steps ahead of an input. In our approach, a LSTM RNN is trained with normal time series data before performing a live prediction for each time step. Instead of considering each time step separately, the observation of prediction errors from a certain number of time steps is now proposed as a new idea for detecting collective anomalies. The prediction errors from a number of the latest time steps above a threshold will indicate a collective anomaly. The model is built on a time series version of the KDD 1999 dataset. The experiments demonstrate that it is possible to offer reliable and efficient for collective anomaly detection.
no_new_dataset
0.953319
1703.09756
Nhien-An Le-Khac
Nhien-An Le-Khac, M-Tahar Kechadi, Joe Carthy
Admire framework: Distributed data mining on data grid platforms
null
null
null
null
cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we present the ADMIRE architecture; a new framework for developing novel and innovative data mining techniques to deal with very large and distributed heterogeneous datasets in both commercial and academic applications. The main ADMIRE components are detailed as well as its interfaces allowing the user to efficiently develop and implement their data mining applications techniques on a Grid platform such as Globus ToolKit, DGET, etc.
[ { "version": "v1", "created": "Tue, 28 Mar 2017 19:22:42 GMT" } ]
2017-03-30T00:00:00
[ [ "Le-Khac", "Nhien-An", "" ], [ "Kechadi", "M-Tahar", "" ], [ "Carthy", "Joe", "" ] ]
TITLE: Admire framework: Distributed data mining on data grid platforms ABSTRACT: In this paper, we present the ADMIRE architecture; a new framework for developing novel and innovative data mining techniques to deal with very large and distributed heterogeneous datasets in both commercial and academic applications. The main ADMIRE components are detailed as well as its interfaces allowing the user to efficiently develop and implement their data mining applications techniques on a Grid platform such as Globus ToolKit, DGET, etc.
no_new_dataset
0.946498
1703.09775
Dorian Cazau
D. Cazau, G. Revillon, O. Adam
Deep scattering transform applied to note onset detection and instrument recognition
null
null
null
null
stat.ML cs.SD
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Automatic Music Transcription (AMT) is one of the oldest and most well-studied problems in the field of music information retrieval. Within this challenging research field, onset detection and instrument recognition take important places in transcription systems, as they respectively help to determine exact onset times of notes and to recognize the corresponding instrument sources. The aim of this study is to explore the usefulness of multiscale scattering operators for these two tasks on plucked string instrument and piano music. After resuming the theoretical background and illustrating the key features of this sound representation method, we evaluate its performances comparatively to other classical sound representations. Using both MIDI-driven datasets with real instrument samples and real musical pieces, scattering is proved to outperform other sound representations for these AMT subtasks, putting forward its richer sound representation and invariance properties.
[ { "version": "v1", "created": "Tue, 28 Mar 2017 19:57:30 GMT" } ]
2017-03-30T00:00:00
[ [ "Cazau", "D.", "" ], [ "Revillon", "G.", "" ], [ "Adam", "O.", "" ] ]
TITLE: Deep scattering transform applied to note onset detection and instrument recognition ABSTRACT: Automatic Music Transcription (AMT) is one of the oldest and most well-studied problems in the field of music information retrieval. Within this challenging research field, onset detection and instrument recognition take important places in transcription systems, as they respectively help to determine exact onset times of notes and to recognize the corresponding instrument sources. The aim of this study is to explore the usefulness of multiscale scattering operators for these two tasks on plucked string instrument and piano music. After resuming the theoretical background and illustrating the key features of this sound representation method, we evaluate its performances comparatively to other classical sound representations. Using both MIDI-driven datasets with real instrument samples and real musical pieces, scattering is proved to outperform other sound representations for these AMT subtasks, putting forward its richer sound representation and invariance properties.
no_new_dataset
0.936865
1703.09807
Nhien-An Le-Khac
Lamine M. Aouad, Nhien-An Le-Khac, Tahar Kechadi
Grid-based Approaches for Distributed Data Mining Applications
null
null
null
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The data mining field is an important source of large-scale applications and datasets which are getting more and more common. In this paper, we present grid-based approaches for two basic data mining applications, and a performance evaluation on an experimental grid environment that provides interesting monitoring capabilities and configuration tools. We propose a new distributed clustering approach and a distributed frequent itemsets generation well-adapted for grid environments. Performance evaluation is done using the Condor system and its workflow manager DAGMan. We also compare this performance analysis to a simple analytical model to evaluate the overheads related to the workflow engine and the underlying grid system. This will specifically show that realistic performance expectations are currently difficult to achieve on the grid.
[ { "version": "v1", "created": "Tue, 28 Mar 2017 21:19:24 GMT" } ]
2017-03-30T00:00:00
[ [ "Aouad", "Lamine M.", "" ], [ "Le-Khac", "Nhien-An", "" ], [ "Kechadi", "Tahar", "" ] ]
TITLE: Grid-based Approaches for Distributed Data Mining Applications ABSTRACT: The data mining field is an important source of large-scale applications and datasets which are getting more and more common. In this paper, we present grid-based approaches for two basic data mining applications, and a performance evaluation on an experimental grid environment that provides interesting monitoring capabilities and configuration tools. We propose a new distributed clustering approach and a distributed frequent itemsets generation well-adapted for grid environments. Performance evaluation is done using the Condor system and its workflow manager DAGMan. We also compare this performance analysis to a simple analytical model to evaluate the overheads related to the workflow engine and the underlying grid system. This will specifically show that realistic performance expectations are currently difficult to achieve on the grid.
no_new_dataset
0.94428
1703.09856
Joseph Antony A
Joseph Antony, Kevin McGuinness, Kieran Moran and Noel E O'Connor
Automatic Detection of Knee Joints and Quantification of Knee Osteoarthritis Severity using Convolutional Neural Networks
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper introduces a new approach to automatically quantify the severity of knee OA using X-ray images. Automatically quantifying knee OA severity involves two steps: first, automatically localizing the knee joints; next, classifying the localized knee joint images. We introduce a new approach to automatically detect the knee joints using a fully convolutional neural network (FCN). We train convolutional neural networks (CNN) from scratch to automatically quantify the knee OA severity optimizing a weighted ratio of two loss functions: categorical cross-entropy and mean-squared loss. This joint training further improves the overall quantification of knee OA severity, with the added benefit of naturally producing simultaneous multi-class classification and regression outputs. Two public datasets are used to evaluate our approach, the Osteoarthritis Initiative (OAI) and the Multicenter Osteoarthritis Study (MOST), with extremely promising results that outperform existing approaches.
[ { "version": "v1", "created": "Wed, 29 Mar 2017 01:29:32 GMT" } ]
2017-03-30T00:00:00
[ [ "Antony", "Joseph", "" ], [ "McGuinness", "Kevin", "" ], [ "Moran", "Kieran", "" ], [ "O'Connor", "Noel E", "" ] ]
TITLE: Automatic Detection of Knee Joints and Quantification of Knee Osteoarthritis Severity using Convolutional Neural Networks ABSTRACT: This paper introduces a new approach to automatically quantify the severity of knee OA using X-ray images. Automatically quantifying knee OA severity involves two steps: first, automatically localizing the knee joints; next, classifying the localized knee joint images. We introduce a new approach to automatically detect the knee joints using a fully convolutional neural network (FCN). We train convolutional neural networks (CNN) from scratch to automatically quantify the knee OA severity optimizing a weighted ratio of two loss functions: categorical cross-entropy and mean-squared loss. This joint training further improves the overall quantification of knee OA severity, with the added benefit of naturally producing simultaneous multi-class classification and regression outputs. Two public datasets are used to evaluate our approach, the Osteoarthritis Initiative (OAI) and the Multicenter Osteoarthritis Study (MOST), with extremely promising results that outperform existing approaches.
no_new_dataset
0.950641
1703.09891
Hexiang Hu
Hexiang Hu, Zhiwei Deng, Guang-Tong Zhou, Fei Sha, Greg Mori
LabelBank: Revisiting Global Perspectives for Semantic Segmentation
Pre-prints
null
null
null
cs.CV cs.AI cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Semantic segmentation requires a detailed labeling of image pixels by object category. Information derived from local image patches is necessary to describe the detailed shape of individual objects. However, this information is ambiguous and can result in noisy labels. Global inference of image content can instead capture the general semantic concepts present. We advocate that holistic inference of image concepts provides valuable information for detailed pixel labeling. We propose a generic framework to leverage holistic information in the form of a LabelBank for pixel-level segmentation. We show the ability of our framework to improve semantic segmentation performance in a variety of settings. We learn models for extracting a holistic LabelBank from visual cues, attributes, and/or textual descriptions. We demonstrate improvements in semantic segmentation accuracy on standard datasets across a range of state-of-the-art segmentation architectures and holistic inference approaches.
[ { "version": "v1", "created": "Wed, 29 Mar 2017 05:58:21 GMT" } ]
2017-03-30T00:00:00
[ [ "Hu", "Hexiang", "" ], [ "Deng", "Zhiwei", "" ], [ "Zhou", "Guang-Tong", "" ], [ "Sha", "Fei", "" ], [ "Mori", "Greg", "" ] ]
TITLE: LabelBank: Revisiting Global Perspectives for Semantic Segmentation ABSTRACT: Semantic segmentation requires a detailed labeling of image pixels by object category. Information derived from local image patches is necessary to describe the detailed shape of individual objects. However, this information is ambiguous and can result in noisy labels. Global inference of image content can instead capture the general semantic concepts present. We advocate that holistic inference of image concepts provides valuable information for detailed pixel labeling. We propose a generic framework to leverage holistic information in the form of a LabelBank for pixel-level segmentation. We show the ability of our framework to improve semantic segmentation performance in a variety of settings. We learn models for extracting a holistic LabelBank from visual cues, attributes, and/or textual descriptions. We demonstrate improvements in semantic segmentation accuracy on standard datasets across a range of state-of-the-art segmentation architectures and holistic inference approaches.
no_new_dataset
0.948155
1703.09933
Estefania Talavera
Estefania Talavera, Nicola Strisciuglio, Nicolai Petkov, Petia Radeva
Sentiment Recognition in Egocentric Photostreams
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Lifelogging is a process of collecting rich source of information about daily life of people. In this paper, we introduce the problem of sentiment analysis in egocentric events focusing on the moments that compose the images recalling positive, neutral or negative feelings to the observer. We propose a method for the classification of the sentiments in egocentric pictures based on global and semantic image features extracted by Convolutional Neural Networks. We carried out experiments on an egocentric dataset, which we organized in 3 classes on the basis of the sentiment that is recalled to the user (positive, negative or neutral).
[ { "version": "v1", "created": "Wed, 29 Mar 2017 08:38:32 GMT" } ]
2017-03-30T00:00:00
[ [ "Talavera", "Estefania", "" ], [ "Strisciuglio", "Nicola", "" ], [ "Petkov", "Nicolai", "" ], [ "Radeva", "Petia", "" ] ]
TITLE: Sentiment Recognition in Egocentric Photostreams ABSTRACT: Lifelogging is a process of collecting rich source of information about daily life of people. In this paper, we introduce the problem of sentiment analysis in egocentric events focusing on the moments that compose the images recalling positive, neutral or negative feelings to the observer. We propose a method for the classification of the sentiments in egocentric pictures based on global and semantic image features extracted by Convolutional Neural Networks. We carried out experiments on an egocentric dataset, which we organized in 3 classes on the basis of the sentiment that is recalled to the user (positive, negative or neutral).
new_dataset
0.896976
1703.09962
Mitra Baratchi Mitra Baratchi
Mitra Baratchi, Geert Heijenk, Maarten van Steen
Spaceprint: a Mobility-based Fingerprinting Scheme for Public Spaces
null
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we address the problem of how automated situation-awareness can be achieved by learning real-world situations from ubiquitously generated mobility data. Without semantic input about the time and space where situations take place, this turns out to be a fundamental challenging problem. Uncertainties also introduce technical challenges when data is generated in irregular time intervals, being mixed with noise, and errors. Purely relying on temporal patterns observable in mobility data, in this paper, we propose Spaceprint, a fully automated algorithm for finding the repetitive pattern of similar situations in spaces. We evaluate this technique by showing how the latent variables describing the category, and the actual identity of a space can be discovered from the extracted situation patterns. Doing so, we use different real-world mobility datasets with data about the presence of mobile entities in a variety of spaces. We also evaluate the performance of this technique by showing its robustness against uncertainties.
[ { "version": "v1", "created": "Wed, 29 Mar 2017 10:31:04 GMT" } ]
2017-03-30T00:00:00
[ [ "Baratchi", "Mitra", "" ], [ "Heijenk", "Geert", "" ], [ "van Steen", "Maarten", "" ] ]
TITLE: Spaceprint: a Mobility-based Fingerprinting Scheme for Public Spaces ABSTRACT: In this paper, we address the problem of how automated situation-awareness can be achieved by learning real-world situations from ubiquitously generated mobility data. Without semantic input about the time and space where situations take place, this turns out to be a fundamental challenging problem. Uncertainties also introduce technical challenges when data is generated in irregular time intervals, being mixed with noise, and errors. Purely relying on temporal patterns observable in mobility data, in this paper, we propose Spaceprint, a fully automated algorithm for finding the repetitive pattern of similar situations in spaces. We evaluate this technique by showing how the latent variables describing the category, and the actual identity of a space can be discovered from the extracted situation patterns. Doing so, we use different real-world mobility datasets with data about the presence of mobile entities in a variety of spaces. We also evaluate the performance of this technique by showing its robustness against uncertainties.
no_new_dataset
0.949106
1703.09983
Zhiqiang Shen
Zhiqiang Shen and Yu-Gang Jiang and Dequan Wang and Xiangyang Xue
Iterative Object and Part Transfer for Fine-Grained Recognition
To appear in ICME 2017 as an oral paper
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The aim of fine-grained recognition is to identify sub-ordinate categories in images like different species of birds. Existing works have confirmed that, in order to capture the subtle differences across the categories, automatic localization of objects and parts is critical. Most approaches for object and part localization relied on the bottom-up pipeline, where thousands of region proposals are generated and then filtered by pre-trained object/part models. This is computationally expensive and not scalable once the number of objects/parts becomes large. In this paper, we propose a nonparametric data-driven method for object and part localization. Given an unlabeled test image, our approach transfers annotations from a few similar images retrieved in the training set. In particular, we propose an iterative transfer strategy that gradually refine the predicted bounding boxes. Based on the located objects and parts, deep convolutional features are extracted for recognition. We evaluate our approach on the widely-used CUB200-2011 dataset and a new and large dataset called Birdsnap. On both datasets, we achieve better results than many state-of-the-art approaches, including a few using oracle (manually annotated) bounding boxes in the test images.
[ { "version": "v1", "created": "Wed, 29 Mar 2017 11:50:34 GMT" } ]
2017-03-30T00:00:00
[ [ "Shen", "Zhiqiang", "" ], [ "Jiang", "Yu-Gang", "" ], [ "Wang", "Dequan", "" ], [ "Xue", "Xiangyang", "" ] ]
TITLE: Iterative Object and Part Transfer for Fine-Grained Recognition ABSTRACT: The aim of fine-grained recognition is to identify sub-ordinate categories in images like different species of birds. Existing works have confirmed that, in order to capture the subtle differences across the categories, automatic localization of objects and parts is critical. Most approaches for object and part localization relied on the bottom-up pipeline, where thousands of region proposals are generated and then filtered by pre-trained object/part models. This is computationally expensive and not scalable once the number of objects/parts becomes large. In this paper, we propose a nonparametric data-driven method for object and part localization. Given an unlabeled test image, our approach transfers annotations from a few similar images retrieved in the training set. In particular, we propose an iterative transfer strategy that gradually refine the predicted bounding boxes. Based on the located objects and parts, deep convolutional features are extracted for recognition. We evaluate our approach on the widely-used CUB200-2011 dataset and a new and large dataset called Birdsnap. On both datasets, we achieve better results than many state-of-the-art approaches, including a few using oracle (manually annotated) bounding boxes in the test images.
new_dataset
0.96862
1703.10062
Sofia Ira Ktena
Sofia Ira Ktena, Salim Arslan, Sarah Parisot, Daniel Rueckert
Exploring Heritability of Functional Brain Networks with Inexact Graph Matching
accepted at ISBI 2017: International Symposium on Biomedical Imaging, Apr 2017, Melbourne, Australia
null
null
null
q-bio.NC cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Data-driven brain parcellations aim to provide a more accurate representation of an individual's functional connectivity, since they are able to capture individual variability that arises due to development or disease. This renders comparisons between the emerging brain connectivity networks more challenging, since correspondences between their elements are not preserved. Unveiling these correspondences is of major importance to keep track of local functional connectivity changes. We propose a novel method based on graph edit distance for the comparison of brain graphs directly in their domain, that can accurately reflect similarities between individual networks while providing the network element correspondences. This method is validated on a dataset of 116 twin subjects provided by the Human Connectome Project.
[ { "version": "v1", "created": "Wed, 29 Mar 2017 14:24:52 GMT" } ]
2017-03-30T00:00:00
[ [ "Ktena", "Sofia Ira", "" ], [ "Arslan", "Salim", "" ], [ "Parisot", "Sarah", "" ], [ "Rueckert", "Daniel", "" ] ]
TITLE: Exploring Heritability of Functional Brain Networks with Inexact Graph Matching ABSTRACT: Data-driven brain parcellations aim to provide a more accurate representation of an individual's functional connectivity, since they are able to capture individual variability that arises due to development or disease. This renders comparisons between the emerging brain connectivity networks more challenging, since correspondences between their elements are not preserved. Unveiling these correspondences is of major importance to keep track of local functional connectivity changes. We propose a novel method based on graph edit distance for the comparison of brain graphs directly in their domain, that can accurately reflect similarities between individual networks while providing the network element correspondences. This method is validated on a dataset of 116 twin subjects provided by the Human Connectome Project.
no_new_dataset
0.932269
1509.00117
Alexander Wong
Devinder Kumar, Mohammad Javad Shafiee, Audrey G. Chung, Farzad Khalvati, Masoom A. Haider, Alexander Wong
Discovery Radiomics for Pathologically-Proven Computed Tomography Lung Cancer Prediction
8 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Lung cancer is the leading cause for cancer related deaths. As such, there is an urgent need for a streamlined process that can allow radiologists to provide diagnosis with greater efficiency and accuracy. A powerful tool to do this is radiomics: a high-dimension imaging feature set. In this study, we take the idea of radiomics one step further by introducing the concept of discovery radiomics for lung cancer prediction using CT imaging data. In this study, we realize these custom radiomic sequencers as deep convolutional sequencers using a deep convolutional neural network learning architecture. To illustrate the prognostic power and effectiveness of the radiomic sequences produced by the discovered sequencer, we perform cancer prediction between malignant and benign lesions from 97 patients using the pathologically-proven diagnostic data from the LIDC-IDRI dataset. Using the clinically provided pathologically-proven data as ground truth, the proposed framework provided an average accuracy of 77.52% via 10-fold cross-validation with a sensitivity of 79.06% and specificity of 76.11%, surpassing the state-of-the art method.
[ { "version": "v1", "created": "Tue, 1 Sep 2015 02:00:56 GMT" }, { "version": "v2", "created": "Tue, 20 Oct 2015 19:10:18 GMT" }, { "version": "v3", "created": "Tue, 28 Mar 2017 02:01:31 GMT" } ]
2017-03-29T00:00:00
[ [ "Kumar", "Devinder", "" ], [ "Shafiee", "Mohammad Javad", "" ], [ "Chung", "Audrey G.", "" ], [ "Khalvati", "Farzad", "" ], [ "Haider", "Masoom A.", "" ], [ "Wong", "Alexander", "" ] ]
TITLE: Discovery Radiomics for Pathologically-Proven Computed Tomography Lung Cancer Prediction ABSTRACT: Lung cancer is the leading cause for cancer related deaths. As such, there is an urgent need for a streamlined process that can allow radiologists to provide diagnosis with greater efficiency and accuracy. A powerful tool to do this is radiomics: a high-dimension imaging feature set. In this study, we take the idea of radiomics one step further by introducing the concept of discovery radiomics for lung cancer prediction using CT imaging data. In this study, we realize these custom radiomic sequencers as deep convolutional sequencers using a deep convolutional neural network learning architecture. To illustrate the prognostic power and effectiveness of the radiomic sequences produced by the discovered sequencer, we perform cancer prediction between malignant and benign lesions from 97 patients using the pathologically-proven diagnostic data from the LIDC-IDRI dataset. Using the clinically provided pathologically-proven data as ground truth, the proposed framework provided an average accuracy of 77.52% via 10-fold cross-validation with a sensitivity of 79.06% and specificity of 76.11%, surpassing the state-of-the art method.
no_new_dataset
0.954265
1602.05335
Jing Yang Koh
Jing Yang Koh, Ido Nevat, Derek Leong, and Wai-Choong Wong
Geo-spatial Location Spoofing Detection for Internet of Things
A shorten version of this work has been accepted to the IEEE IoT Journal (IoT-J) on 08-Feb-2016
IEEE Internet of Things Journal, vol. 3, no. 6, pp. 971-978, Dec. 2016
10.1109/JIOT.2016.2535165
null
cs.CR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We develop a new location spoofing detection algorithm for geo-spatial tagging and location-based services in the Internet of Things (IoT), called Enhanced Location Spoofing Detection using Audibility (ELSA) which can be implemented at the backend server without modifying existing legacy IoT systems. ELSA is based on a statistical decision theory framework and uses two-way time-of-arrival (TW-TOA) information between the user's device and the anchors. In addition to the TW-TOA information, ELSA exploits the implicit available audibility information to improve detection rates of location spoofing attacks. Given TW-TOA and audibility information, we derive the decision rule for the verification of the device's location, based on the generalized likelihood ratio test. We develop a practical threat model for delay measurements spoofing scenarios, and investigate in detail the performance of ELSA in terms of detection and false alarm rates. Our extensive simulation results on both synthetic and real-world datasets demonstrate the superior performance of ELSA compared to conventional non-audibility-aware approaches.
[ { "version": "v1", "created": "Wed, 17 Feb 2016 09:03:06 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 08:54:43 GMT" } ]
2017-03-29T00:00:00
[ [ "Koh", "Jing Yang", "" ], [ "Nevat", "Ido", "" ], [ "Leong", "Derek", "" ], [ "Wong", "Wai-Choong", "" ] ]
TITLE: Geo-spatial Location Spoofing Detection for Internet of Things ABSTRACT: We develop a new location spoofing detection algorithm for geo-spatial tagging and location-based services in the Internet of Things (IoT), called Enhanced Location Spoofing Detection using Audibility (ELSA) which can be implemented at the backend server without modifying existing legacy IoT systems. ELSA is based on a statistical decision theory framework and uses two-way time-of-arrival (TW-TOA) information between the user's device and the anchors. In addition to the TW-TOA information, ELSA exploits the implicit available audibility information to improve detection rates of location spoofing attacks. Given TW-TOA and audibility information, we derive the decision rule for the verification of the device's location, based on the generalized likelihood ratio test. We develop a practical threat model for delay measurements spoofing scenarios, and investigate in detail the performance of ELSA in terms of detection and false alarm rates. Our extensive simulation results on both synthetic and real-world datasets demonstrate the superior performance of ELSA compared to conventional non-audibility-aware approaches.
no_new_dataset
0.948917
1603.05544
Linnan Wang
Linnan Wang, Yi Yang, Martin Renqiang Min, Srimat Chakradhar
Accelerating Deep Neural Network Training with Inconsistent Stochastic Gradient Descent
The patent of ISGD belongs to NEC Labs
null
null
null
cs.LG cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
SGD is the widely adopted method to train CNN. Conceptually it approximates the population with a randomly sampled batch; then it evenly trains batches by conducting a gradient update on every batch in an epoch. In this paper, we demonstrate Sampling Bias, Intrinsic Image Difference and Fixed Cycle Pseudo Random Sampling differentiate batches in training, which then affect learning speeds on them. Because of this, the unbiased treatment of batches involved in SGD creates improper load balancing. To address this issue, we present Inconsistent Stochastic Gradient Descent (ISGD) to dynamically vary training effort according to learning statuses on batches. Specifically ISGD leverages techniques in Statistical Process Control to identify a undertrained batch. Once a batch is undertrained, ISGD solves a new subproblem, a chasing logic plus a conservative constraint, to accelerate the training on the batch while avoid drastic parameter changes. Extensive experiments on a variety of datasets demonstrate ISGD converges faster than SGD. In training AlexNet, ISGD is 21.05\% faster than SGD to reach 56\% top1 accuracy under the exactly same experiment setup. We also extend ISGD to work on multiGPU or heterogeneous distributed system based on data parallelism, enabling the batch size to be the key to scalability. Then we present the study of ISGD batch size to the learning rate, parallelism, synchronization cost, system saturation and scalability. We conclude the optimal ISGD batch size is machine dependent. Various experiments on a multiGPU system validate our claim. In particular, ISGD trains AlexNet to 56.3% top1 and 80.1% top5 accuracy in 11.5 hours with 4 NVIDIA TITAN X at the batch size of 1536.
[ { "version": "v1", "created": "Thu, 17 Mar 2016 15:49:48 GMT" }, { "version": "v2", "created": "Fri, 18 Mar 2016 05:35:22 GMT" }, { "version": "v3", "created": "Tue, 28 Mar 2017 13:56:03 GMT" } ]
2017-03-29T00:00:00
[ [ "Wang", "Linnan", "" ], [ "Yang", "Yi", "" ], [ "Min", "Martin Renqiang", "" ], [ "Chakradhar", "Srimat", "" ] ]
TITLE: Accelerating Deep Neural Network Training with Inconsistent Stochastic Gradient Descent ABSTRACT: SGD is the widely adopted method to train CNN. Conceptually it approximates the population with a randomly sampled batch; then it evenly trains batches by conducting a gradient update on every batch in an epoch. In this paper, we demonstrate Sampling Bias, Intrinsic Image Difference and Fixed Cycle Pseudo Random Sampling differentiate batches in training, which then affect learning speeds on them. Because of this, the unbiased treatment of batches involved in SGD creates improper load balancing. To address this issue, we present Inconsistent Stochastic Gradient Descent (ISGD) to dynamically vary training effort according to learning statuses on batches. Specifically ISGD leverages techniques in Statistical Process Control to identify a undertrained batch. Once a batch is undertrained, ISGD solves a new subproblem, a chasing logic plus a conservative constraint, to accelerate the training on the batch while avoid drastic parameter changes. Extensive experiments on a variety of datasets demonstrate ISGD converges faster than SGD. In training AlexNet, ISGD is 21.05\% faster than SGD to reach 56\% top1 accuracy under the exactly same experiment setup. We also extend ISGD to work on multiGPU or heterogeneous distributed system based on data parallelism, enabling the batch size to be the key to scalability. Then we present the study of ISGD batch size to the learning rate, parallelism, synchronization cost, system saturation and scalability. We conclude the optimal ISGD batch size is machine dependent. Various experiments on a multiGPU system validate our claim. In particular, ISGD trains AlexNet to 56.3% top1 and 80.1% top5 accuracy in 11.5 hours with 4 NVIDIA TITAN X at the batch size of 1536.
no_new_dataset
0.945045
1604.01431
Wei-Chiu Ma
Wei-Chiu Ma, De-An Huang, Namhoon Lee, Kris M. Kitani
Forecasting Interactive Dynamics of Pedestrians with Fictitious Play
Accepted to CVPR 2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We develop predictive models of pedestrian dynamics by encoding the coupled nature of multi-pedestrian interaction using game theory, and deep learning-based visual analysis to estimate person-specific behavior parameters. Building predictive models for multi-pedestrian interactions however, is very challenging due to two reasons: (1) the dynamics of interaction are complex interdependent processes, where the predicted behavior of one pedestrian can affect the actions taken by others and (2) dynamics are variable depending on an individuals physical characteristics (e.g., an older person may walk slowly while the younger person may walk faster). To address these challenges, we (1) utilize concepts from game theory to model the interdependent decision making process of multiple pedestrians and (2) use visual classifiers to learn a mapping from pedestrian appearance to behavior parameters. We evaluate our proposed model on several public multiple pedestrian interaction video datasets. Results show that our strategic planning model explains human interactions 25% better when compared to state-of-the-art methods.
[ { "version": "v1", "created": "Tue, 5 Apr 2016 21:13:32 GMT" }, { "version": "v2", "created": "Mon, 9 May 2016 18:07:23 GMT" }, { "version": "v3", "created": "Tue, 28 Mar 2017 16:31:01 GMT" } ]
2017-03-29T00:00:00
[ [ "Ma", "Wei-Chiu", "" ], [ "Huang", "De-An", "" ], [ "Lee", "Namhoon", "" ], [ "Kitani", "Kris M.", "" ] ]
TITLE: Forecasting Interactive Dynamics of Pedestrians with Fictitious Play ABSTRACT: We develop predictive models of pedestrian dynamics by encoding the coupled nature of multi-pedestrian interaction using game theory, and deep learning-based visual analysis to estimate person-specific behavior parameters. Building predictive models for multi-pedestrian interactions however, is very challenging due to two reasons: (1) the dynamics of interaction are complex interdependent processes, where the predicted behavior of one pedestrian can affect the actions taken by others and (2) dynamics are variable depending on an individuals physical characteristics (e.g., an older person may walk slowly while the younger person may walk faster). To address these challenges, we (1) utilize concepts from game theory to model the interdependent decision making process of multiple pedestrians and (2) use visual classifiers to learn a mapping from pedestrian appearance to behavior parameters. We evaluate our proposed model on several public multiple pedestrian interaction video datasets. Results show that our strategic planning model explains human interactions 25% better when compared to state-of-the-art methods.
no_new_dataset
0.947769
1607.06179
Ninh Pham
Ninh Pham
Hybrid LSH: Faster Near Neighbors Reporting in High-dimensional Space
Accepted as a short paper in EDBT 2017
null
null
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the $r$-near neighbors reporting problem ($r$-NN), i.e., reporting \emph{all} points in a high-dimensional point set $S$ that lie within a radius $r$ of a given query point $q$. Our approach builds upon on the locality-sensitive hashing (LSH) framework due to its appealing asymptotic sublinear query time for near neighbor search problems in high-dimensional space. A bottleneck of the traditional LSH scheme for solving $r$-NN is that its performance is sensitive to data and query-dependent parameters. On datasets whose data distributions have diverse local density patterns, LSH with inappropriate tuning parameters can sometimes be outperformed by a simple linear search. In this paper, we introduce a hybrid search strategy between LSH-based search and linear search for $r$-NN in high-dimensional space. By integrating an auxiliary data structure into LSH hash tables, we can efficiently estimate the computational cost of LSH-based search for a given query regardless of the data distribution. This means that we are able to choose the appropriate search strategy between LSH-based search and linear search to achieve better performance. Moreover, the integrated data structure is time efficient and fits well with many recent state-of-the-art LSH-based approaches. Our experiments on real-world datasets show that the hybrid search approach outperforms (or is comparable to) both LSH-based search and linear search for a wide range of search radii and data distributions in high-dimensional space.
[ { "version": "v1", "created": "Thu, 21 Jul 2016 03:24:06 GMT" }, { "version": "v2", "created": "Sat, 7 Jan 2017 02:28:08 GMT" }, { "version": "v3", "created": "Tue, 28 Mar 2017 12:30:35 GMT" } ]
2017-03-29T00:00:00
[ [ "Pham", "Ninh", "" ] ]
TITLE: Hybrid LSH: Faster Near Neighbors Reporting in High-dimensional Space ABSTRACT: We study the $r$-near neighbors reporting problem ($r$-NN), i.e., reporting \emph{all} points in a high-dimensional point set $S$ that lie within a radius $r$ of a given query point $q$. Our approach builds upon on the locality-sensitive hashing (LSH) framework due to its appealing asymptotic sublinear query time for near neighbor search problems in high-dimensional space. A bottleneck of the traditional LSH scheme for solving $r$-NN is that its performance is sensitive to data and query-dependent parameters. On datasets whose data distributions have diverse local density patterns, LSH with inappropriate tuning parameters can sometimes be outperformed by a simple linear search. In this paper, we introduce a hybrid search strategy between LSH-based search and linear search for $r$-NN in high-dimensional space. By integrating an auxiliary data structure into LSH hash tables, we can efficiently estimate the computational cost of LSH-based search for a given query regardless of the data distribution. This means that we are able to choose the appropriate search strategy between LSH-based search and linear search to achieve better performance. Moreover, the integrated data structure is time efficient and fits well with many recent state-of-the-art LSH-based approaches. Our experiments on real-world datasets show that the hybrid search approach outperforms (or is comparable to) both LSH-based search and linear search for a wide range of search radii and data distributions in high-dimensional space.
no_new_dataset
0.950686
1611.07156
Yazhou Yao
Yazhou Yao, Jian Zhang, Fumin Shen, Xiansheng Hua, Jingsong Xu and Zhenmin Tang
Exploiting Web Images for Dataset Construction: A Domain Robust Approach
Journal
null
10.1109/TMM.2017.2684626
null
cs.CV cs.MM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Labelled image datasets have played a critical role in high-level image understanding. However, the process of manual labelling is both time-consuming and labor intensive. To reduce the cost of manual labelling, there has been increased research interest in automatically constructing image datasets by exploiting web images. Datasets constructed by existing methods tend to have a weak domain adaptation ability, which is known as the "dataset bias problem". To address this issue, we present a novel image dataset construction framework that can be generalized well to unseen target domains. Specifically, the given queries are first expanded by searching the Google Books Ngrams Corpus to obtain a rich semantic description, from which the visually non-salient and less relevant expansions are filtered out. By treating each selected expansion as a "bag" and the retrieved images as "instances", image selection can be formulated as a multi-instance learning problem with constrained positive bags. We propose to solve the employed problems by the cutting-plane and concave-convex procedure (CCCP) algorithm. By using this approach, images from different distributions can be kept while noisy images are filtered out. To verify the effectiveness of our proposed approach, we build an image dataset with 20 categories. Extensive experiments on image classification, cross-dataset generalization, diversity comparison and object detection demonstrate the domain robustness of our dataset.
[ { "version": "v1", "created": "Tue, 22 Nov 2016 06:22:19 GMT" }, { "version": "v2", "created": "Wed, 22 Feb 2017 23:53:20 GMT" }, { "version": "v3", "created": "Thu, 16 Mar 2017 22:54:15 GMT" }, { "version": "v4", "created": "Tue, 28 Mar 2017 06:30:41 GMT" } ]
2017-03-29T00:00:00
[ [ "Yao", "Yazhou", "" ], [ "Zhang", "Jian", "" ], [ "Shen", "Fumin", "" ], [ "Hua", "Xiansheng", "" ], [ "Xu", "Jingsong", "" ], [ "Tang", "Zhenmin", "" ] ]
TITLE: Exploiting Web Images for Dataset Construction: A Domain Robust Approach ABSTRACT: Labelled image datasets have played a critical role in high-level image understanding. However, the process of manual labelling is both time-consuming and labor intensive. To reduce the cost of manual labelling, there has been increased research interest in automatically constructing image datasets by exploiting web images. Datasets constructed by existing methods tend to have a weak domain adaptation ability, which is known as the "dataset bias problem". To address this issue, we present a novel image dataset construction framework that can be generalized well to unseen target domains. Specifically, the given queries are first expanded by searching the Google Books Ngrams Corpus to obtain a rich semantic description, from which the visually non-salient and less relevant expansions are filtered out. By treating each selected expansion as a "bag" and the retrieved images as "instances", image selection can be formulated as a multi-instance learning problem with constrained positive bags. We propose to solve the employed problems by the cutting-plane and concave-convex procedure (CCCP) algorithm. By using this approach, images from different distributions can be kept while noisy images are filtered out. To verify the effectiveness of our proposed approach, we build an image dataset with 20 categories. Extensive experiments on image classification, cross-dataset generalization, diversity comparison and object detection demonstrate the domain robustness of our dataset.
no_new_dataset
0.904693
1611.07485
Qiangui Huang
Qiangui Huang, Weiyue Wang, Kevin Zhou, Suya You, Ulrich Neumann
Scene Labeling using Gated Recurrent Units with Explicit Long Range Conditioning
updated version 2
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recurrent neural network (RNN), as a powerful contextual dependency modeling framework, has been widely applied to scene labeling problems. However, this work shows that directly applying traditional RNN architectures, which unfolds a 2D lattice grid into a sequence, is not sufficient to model structure dependencies in images due to the "impact vanishing" problem. First, we give an empirical analysis about the "impact vanishing" problem. Then, a new RNN unit named Recurrent Neural Network with explicit long range conditioning (RNN-ELC) is designed to alleviate this problem. A novel neural network architecture is built for scene labeling tasks where one of the variants of the new RNN unit, Gated Recurrent Unit with Explicit Long-range Conditioning (GRU-ELC), is used to model multi scale contextual dependencies in images. We validate the use of GRU-ELC units with state-of-the-art performance on three standard scene labeling datasets. Comprehensive experiments demonstrate that the new GRU-ELC unit benefits scene labeling problem a lot as it can encode longer contextual dependencies in images more effectively than traditional RNN units.
[ { "version": "v1", "created": "Tue, 22 Nov 2016 19:43:24 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 05:12:44 GMT" } ]
2017-03-29T00:00:00
[ [ "Huang", "Qiangui", "" ], [ "Wang", "Weiyue", "" ], [ "Zhou", "Kevin", "" ], [ "You", "Suya", "" ], [ "Neumann", "Ulrich", "" ] ]
TITLE: Scene Labeling using Gated Recurrent Units with Explicit Long Range Conditioning ABSTRACT: Recurrent neural network (RNN), as a powerful contextual dependency modeling framework, has been widely applied to scene labeling problems. However, this work shows that directly applying traditional RNN architectures, which unfolds a 2D lattice grid into a sequence, is not sufficient to model structure dependencies in images due to the "impact vanishing" problem. First, we give an empirical analysis about the "impact vanishing" problem. Then, a new RNN unit named Recurrent Neural Network with explicit long range conditioning (RNN-ELC) is designed to alleviate this problem. A novel neural network architecture is built for scene labeling tasks where one of the variants of the new RNN unit, Gated Recurrent Unit with Explicit Long-range Conditioning (GRU-ELC), is used to model multi scale contextual dependencies in images. We validate the use of GRU-ELC units with state-of-the-art performance on three standard scene labeling datasets. Comprehensive experiments demonstrate that the new GRU-ELC unit benefits scene labeling problem a lot as it can encode longer contextual dependencies in images more effectively than traditional RNN units.
no_new_dataset
0.950411
1702.00648
Niannan Xue
Niannan Xue, Yannis Panagakis, Stefanos Zafeiriou
Side Information in Robust Principal Component Analysis: Algorithms and Applications
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Robust Principal Component Analysis (RPCA) aims at recovering a low-rank subspace from grossly corrupted high-dimensional (often visual) data and is a cornerstone in many machine learning and computer vision applications. Even though RPCA has been shown to be very successful in solving many rank minimisation problems, there are still cases where degenerate or suboptimal solutions are obtained. This is likely to be remedied by taking into account of domain-dependent prior knowledge. In this paper, we propose two models for the RPCA problem with the aid of side information on the low-rank structure of the data. The versatility of the proposed methods is demonstrated by applying them to four applications, namely background subtraction, facial image denoising, face and facial expression recognition. Experimental results on synthetic and five real world datasets indicate the robustness and effectiveness of the proposed methods on these application domains, largely outperforming six previous approaches.
[ { "version": "v1", "created": "Thu, 2 Feb 2017 12:42:50 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 16:23:44 GMT" } ]
2017-03-29T00:00:00
[ [ "Xue", "Niannan", "" ], [ "Panagakis", "Yannis", "" ], [ "Zafeiriou", "Stefanos", "" ] ]
TITLE: Side Information in Robust Principal Component Analysis: Algorithms and Applications ABSTRACT: Robust Principal Component Analysis (RPCA) aims at recovering a low-rank subspace from grossly corrupted high-dimensional (often visual) data and is a cornerstone in many machine learning and computer vision applications. Even though RPCA has been shown to be very successful in solving many rank minimisation problems, there are still cases where degenerate or suboptimal solutions are obtained. This is likely to be remedied by taking into account of domain-dependent prior knowledge. In this paper, we propose two models for the RPCA problem with the aid of side information on the low-rank structure of the data. The versatility of the proposed methods is demonstrated by applying them to four applications, namely background subtraction, facial image denoising, face and facial expression recognition. Experimental results on synthetic and five real world datasets indicate the robustness and effectiveness of the proposed methods on these application domains, largely outperforming six previous approaches.
no_new_dataset
0.945248
1703.07475
Chunhui Liu
Chunhui Liu, and Yueyu Hu, and Yanghao Li, and Sijie Song, and Jiaying Liu
PKU-MMD: A Large Scale Benchmark for Continuous Multi-Modal Human Action Understanding
10 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Despite the fact that many 3D human activity benchmarks being proposed, most existing action datasets focus on the action recognition tasks for the segmented videos. There is a lack of standard large-scale benchmarks, especially for current popular data-hungry deep learning based methods. In this paper, we introduce a new large scale benchmark (PKU-MMD) for continuous multi-modality 3D human action understanding and cover a wide range of complex human activities with well annotated information. PKU-MMD contains 1076 long video sequences in 51 action categories, performed by 66 subjects in three camera views. It contains almost 20,000 action instances and 5.4 million frames in total. Our dataset also provides multi-modality data sources, including RGB, depth, Infrared Radiation and Skeleton. With different modalities, we conduct extensive experiments on our dataset in terms of two scenarios and evaluate different methods by various metrics, including a new proposed evaluation protocol 2D-AP. We believe this large-scale dataset will benefit future researches on action detection for the community.
[ { "version": "v1", "created": "Wed, 22 Mar 2017 00:22:49 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 01:01:29 GMT" } ]
2017-03-29T00:00:00
[ [ "Liu", "Chunhui", "" ], [ "Hu", "Yueyu", "" ], [ "Li", "Yanghao", "" ], [ "Song", "Sijie", "" ], [ "Liu", "Jiaying", "" ] ]
TITLE: PKU-MMD: A Large Scale Benchmark for Continuous Multi-Modal Human Action Understanding ABSTRACT: Despite the fact that many 3D human activity benchmarks being proposed, most existing action datasets focus on the action recognition tasks for the segmented videos. There is a lack of standard large-scale benchmarks, especially for current popular data-hungry deep learning based methods. In this paper, we introduce a new large scale benchmark (PKU-MMD) for continuous multi-modality 3D human action understanding and cover a wide range of complex human activities with well annotated information. PKU-MMD contains 1076 long video sequences in 51 action categories, performed by 66 subjects in three camera views. It contains almost 20,000 action instances and 5.4 million frames in total. Our dataset also provides multi-modality data sources, including RGB, depth, Infrared Radiation and Skeleton. With different modalities, we conduct extensive experiments on our dataset in terms of two scenarios and evaluate different methods by various metrics, including a new proposed evaluation protocol 2D-AP. We believe this large-scale dataset will benefit future researches on action detection for the community.
new_dataset
0.969699
1703.07957
Yohann Salaun
Yohann Salaun, Renaud Marlet, and Pascal Monasse
Robust SfM with Little Image Overlap
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Usual Structure-from-Motion (SfM) techniques require at least trifocal overlaps to calibrate cameras and reconstruct a scene. We consider here scenarios of reduced image sets with little overlap, possibly as low as two images at most seeing the same part of the scene. We propose a new method, based on line coplanarity hypotheses, for estimating the relative scale of two independent bifocal calibrations sharing a camera, without the need of any trifocal information or Manhattan-world assumption. We use it to compute SfM in a chain of up-to-scale relative motions. For accuracy, we however also make use of trifocal information for line and/or point features, when present, relaxing usual trifocal constraints. For robustness to wrong assumptions and mismatches, we embed all constraints in a parameterless RANSAC-like approach. Experiments show that we can calibrate datasets that previously could not, and that this wider applicability does not come at the cost of inaccuracy.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 07:52:31 GMT" }, { "version": "v2", "created": "Tue, 28 Mar 2017 09:57:56 GMT" } ]
2017-03-29T00:00:00
[ [ "Salaun", "Yohann", "" ], [ "Marlet", "Renaud", "" ], [ "Monasse", "Pascal", "" ] ]
TITLE: Robust SfM with Little Image Overlap ABSTRACT: Usual Structure-from-Motion (SfM) techniques require at least trifocal overlaps to calibrate cameras and reconstruct a scene. We consider here scenarios of reduced image sets with little overlap, possibly as low as two images at most seeing the same part of the scene. We propose a new method, based on line coplanarity hypotheses, for estimating the relative scale of two independent bifocal calibrations sharing a camera, without the need of any trifocal information or Manhattan-world assumption. We use it to compute SfM in a chain of up-to-scale relative motions. For accuracy, we however also make use of trifocal information for line and/or point features, when present, relaxing usual trifocal constraints. For robustness to wrong assumptions and mismatches, we embed all constraints in a parameterless RANSAC-like approach. Experiments show that we can calibrate datasets that previously could not, and that this wider applicability does not come at the cost of inaccuracy.
no_new_dataset
0.94699
1703.09474
Ancong Wu
Ancong Wu, Wei-Shi Zheng, Jianhuang Lai
Robust Depth-based Person Re-identification
IEEE Transactions on Image Processing Early Access
null
10.1109/TIP.2017.2675201
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Person re-identification (re-id) aims to match people across non-overlapping camera views. So far the RGB-based appearance is widely used in most existing works. However, when people appeared in extreme illumination or changed clothes, the RGB appearance-based re-id methods tended to fail. To overcome this problem, we propose to exploit depth information to provide more invariant body shape and skeleton information regardless of illumination and color change. More specifically, we exploit depth voxel covariance descriptor and further propose a locally rotation invariant depth shape descriptor called Eigen-depth feature to describe pedestrian body shape. We prove that the distance between any two covariance matrices on the Riemannian manifold is equivalent to the Euclidean distance between the corresponding Eigen-depth features. Furthermore, we propose a kernelized implicit feature transfer scheme to estimate Eigen-depth feature implicitly from RGB image when depth information is not available. We find that combining the estimated depth features with RGB-based appearance features can sometimes help to better reduce visual ambiguities of appearance features caused by illumination and similar clothes. The effectiveness of our models was validated on publicly available depth pedestrian datasets as compared to related methods for person re-identification.
[ { "version": "v1", "created": "Tue, 28 Mar 2017 09:26:54 GMT" } ]
2017-03-29T00:00:00
[ [ "Wu", "Ancong", "" ], [ "Zheng", "Wei-Shi", "" ], [ "Lai", "Jianhuang", "" ] ]
TITLE: Robust Depth-based Person Re-identification ABSTRACT: Person re-identification (re-id) aims to match people across non-overlapping camera views. So far the RGB-based appearance is widely used in most existing works. However, when people appeared in extreme illumination or changed clothes, the RGB appearance-based re-id methods tended to fail. To overcome this problem, we propose to exploit depth information to provide more invariant body shape and skeleton information regardless of illumination and color change. More specifically, we exploit depth voxel covariance descriptor and further propose a locally rotation invariant depth shape descriptor called Eigen-depth feature to describe pedestrian body shape. We prove that the distance between any two covariance matrices on the Riemannian manifold is equivalent to the Euclidean distance between the corresponding Eigen-depth features. Furthermore, we propose a kernelized implicit feature transfer scheme to estimate Eigen-depth feature implicitly from RGB image when depth information is not available. We find that combining the estimated depth features with RGB-based appearance features can sometimes help to better reduce visual ambiguities of appearance features caused by illumination and similar clothes. The effectiveness of our models was validated on publicly available depth pedestrian datasets as compared to related methods for person re-identification.
no_new_dataset
0.953319
1703.09513
Aleksey Buzmakov
Aleksey Buzmakov and Sergei O. Kuznetsov and Amedeo Napoli
Mining Best Closed Itemsets for Projection-antimonotonic Constraints in Polynomial Time
null
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The exponential explosion of the set of patterns is one of the main challenges in pattern mining. This challenge is approached by introducing a constraint for pattern selection. One of the first constraints proposed in pattern mining is support (frequency) of a pattern in a dataset. Frequency is an anti-monotonic function, i.e., given an infrequent pattern, all its superpatterns are not frequent. However, many other constraints for pattern selection are neither monotonic nor anti-monotonic, which makes it difficult to generate patterns satisfying these constraints. In order to deal with nonmonotonic constraints we introduce the notion of "projection antimonotonicity" and SOFIA algorithm that allow generating best patterns for a class of nonmonotonic constraints. Cosine interest, robustness, stability of closed itemsets, and the associated delta-measure are among these constraints. SOFIA starts from light descriptions of transactions in dataset (a small set of items in the case of itemset description) and then iteratively adds more information to these descriptions (more items with indication of tidsets they describe).
[ { "version": "v1", "created": "Tue, 28 Mar 2017 11:40:44 GMT" } ]
2017-03-29T00:00:00
[ [ "Buzmakov", "Aleksey", "" ], [ "Kuznetsov", "Sergei O.", "" ], [ "Napoli", "Amedeo", "" ] ]
TITLE: Mining Best Closed Itemsets for Projection-antimonotonic Constraints in Polynomial Time ABSTRACT: The exponential explosion of the set of patterns is one of the main challenges in pattern mining. This challenge is approached by introducing a constraint for pattern selection. One of the first constraints proposed in pattern mining is support (frequency) of a pattern in a dataset. Frequency is an anti-monotonic function, i.e., given an infrequent pattern, all its superpatterns are not frequent. However, many other constraints for pattern selection are neither monotonic nor anti-monotonic, which makes it difficult to generate patterns satisfying these constraints. In order to deal with nonmonotonic constraints we introduce the notion of "projection antimonotonicity" and SOFIA algorithm that allow generating best patterns for a class of nonmonotonic constraints. Cosine interest, robustness, stability of closed itemsets, and the associated delta-measure are among these constraints. SOFIA starts from light descriptions of transactions in dataset (a small set of items in the case of itemset description) and then iteratively adds more information to these descriptions (more items with indication of tidsets they describe).
no_new_dataset
0.947137
1703.09695
Nasim Souly
Nasim Souly, Concetto Spampinato and Mubarak Shah
Semi and Weakly Supervised Semantic Segmentation Using Generative Adversarial Network
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Semantic segmentation has been a long standing challenging task in computer vision. It aims at assigning a label to each image pixel and needs significant number of pixellevel annotated data, which is often unavailable. To address this lack, in this paper, we leverage, on one hand, massive amount of available unlabeled or weakly labeled data, and on the other hand, non-real images created through Generative Adversarial Networks. In particular, we propose a semi-supervised framework ,based on Generative Adversarial Networks (GANs), which consists of a generator network to provide extra training examples to a multi-class classifier, acting as discriminator in the GAN framework, that assigns sample a label y from the K possible classes or marks it as a fake sample (extra class). The underlying idea is that adding large fake visual data forces real samples to be close in the feature space, enabling a bottom-up clustering process, which, in turn, improves multiclass pixel classification. To ensure higher quality of generated images for GANs with consequent improved pixel classification, we extend the above framework by adding weakly annotated data, i.e., we provide class level information to the generator. We tested our approaches on several challenging benchmarking visual datasets, i.e. PASCAL, SiftFLow, Stanford and CamVid, achieving competitive performance also compared to state-of-the-art semantic segmentation method
[ { "version": "v1", "created": "Tue, 28 Mar 2017 17:57:21 GMT" } ]
2017-03-29T00:00:00
[ [ "Souly", "Nasim", "" ], [ "Spampinato", "Concetto", "" ], [ "Shah", "Mubarak", "" ] ]
TITLE: Semi and Weakly Supervised Semantic Segmentation Using Generative Adversarial Network ABSTRACT: Semantic segmentation has been a long standing challenging task in computer vision. It aims at assigning a label to each image pixel and needs significant number of pixellevel annotated data, which is often unavailable. To address this lack, in this paper, we leverage, on one hand, massive amount of available unlabeled or weakly labeled data, and on the other hand, non-real images created through Generative Adversarial Networks. In particular, we propose a semi-supervised framework ,based on Generative Adversarial Networks (GANs), which consists of a generator network to provide extra training examples to a multi-class classifier, acting as discriminator in the GAN framework, that assigns sample a label y from the K possible classes or marks it as a fake sample (extra class). The underlying idea is that adding large fake visual data forces real samples to be close in the feature space, enabling a bottom-up clustering process, which, in turn, improves multiclass pixel classification. To ensure higher quality of generated images for GANs with consequent improved pixel classification, we extend the above framework by adding weakly annotated data, i.e., we provide class level information to the generator. We tested our approaches on several challenging benchmarking visual datasets, i.e. PASCAL, SiftFLow, Stanford and CamVid, achieving competitive performance also compared to state-of-the-art semantic segmentation method
no_new_dataset
0.956186
1607.06025
Janez Starc
Janez Starc and Dunja Mladeni\'c
Constructing a Natural Language Inference Dataset using Generative Neural Networks
null
null
null
null
cs.AI cs.CL cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Natural Language Inference is an important task for Natural Language Understanding. It is concerned with classifying the logical relation between two sentences. In this paper, we propose several text generative neural networks for generating text hypothesis, which allows construction of new Natural Language Inference datasets. To evaluate the models, we propose a new metric -- the accuracy of the classifier trained on the generated dataset. The accuracy obtained by our best generative model is only 2.7% lower than the accuracy of the classifier trained on the original, human crafted dataset. Furthermore, the best generated dataset combined with the original dataset achieves the highest accuracy. The best model learns a mapping embedding for each training example. By comparing various metrics we show that datasets that obtain higher ROUGE or METEOR scores do not necessarily yield higher classification accuracies. We also provide analysis of what are the characteristics of a good dataset including the distinguishability of the generated datasets from the original one.
[ { "version": "v1", "created": "Wed, 20 Jul 2016 16:59:21 GMT" }, { "version": "v2", "created": "Mon, 27 Mar 2017 08:33:27 GMT" } ]
2017-03-28T00:00:00
[ [ "Starc", "Janez", "" ], [ "Mladenić", "Dunja", "" ] ]
TITLE: Constructing a Natural Language Inference Dataset using Generative Neural Networks ABSTRACT: Natural Language Inference is an important task for Natural Language Understanding. It is concerned with classifying the logical relation between two sentences. In this paper, we propose several text generative neural networks for generating text hypothesis, which allows construction of new Natural Language Inference datasets. To evaluate the models, we propose a new metric -- the accuracy of the classifier trained on the generated dataset. The accuracy obtained by our best generative model is only 2.7% lower than the accuracy of the classifier trained on the original, human crafted dataset. Furthermore, the best generated dataset combined with the original dataset achieves the highest accuracy. The best model learns a mapping embedding for each training example. By comparing various metrics we show that datasets that obtain higher ROUGE or METEOR scores do not necessarily yield higher classification accuracies. We also provide analysis of what are the characteristics of a good dataset including the distinguishability of the generated datasets from the original one.
no_new_dataset
0.701279
1608.05339
Wei-Tse Sun
Wei-Tse Sun, Ting-Hsuan Chao, Yin-Hsi Kuo, Winston H. Hsu
Photo Filter Recommendation by Category-Aware Aesthetic Learning
11 pages, 7 figures
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Nowadays, social media has become a popular platform for the public to share photos. To make photos more visually appealing, users usually apply filters on their photos without domain knowledge. However, due to the growing number of filter types, it becomes a major issue for users to choose the best filter type. For this purpose, filter recommendation for photo aesthetics takes an important role in image quality ranking problems. In these years, several works have declared that Convolutional Neural Networks (CNNs) outperform traditional methods in image aesthetic categorization, which classifies images into high or low quality. Most of them do not consider the effect on filtered images; hence, we propose a novel image aesthetic learning for filter recommendation. Instead of binarizing image quality, we adjust the state-of-the-art CNN architectures and design a pairwise loss function to learn the embedded aesthetic responses in hidden layers for filtered images. Based on our pilot study, we observe image categories (e.g., portrait, landscape, food) will affect user preference on filter selection. We further integrate category classification into our proposed aesthetic-oriented models. To the best of our knowledge, there is no public dataset for aesthetic judgment with filtered images. We create a new dataset called Filter Aesthetic Comparison Dataset (FACD). It contains 28,160 filtered images based on the AVA dataset and 42,240 reliable image pairs with aesthetic annotations using Amazon Mechanical Turk. It is the first dataset containing filtered images and user preference labels. We conduct experiments on the collected FACD for filter recommendation, and the results show that our proposed category-aware aesthetic learning outperforms aesthetic classification methods (e.g., 12% relative improvement).
[ { "version": "v1", "created": "Thu, 18 Aug 2016 17:22:54 GMT" }, { "version": "v2", "created": "Mon, 27 Mar 2017 05:07:06 GMT" } ]
2017-03-28T00:00:00
[ [ "Sun", "Wei-Tse", "" ], [ "Chao", "Ting-Hsuan", "" ], [ "Kuo", "Yin-Hsi", "" ], [ "Hsu", "Winston H.", "" ] ]
TITLE: Photo Filter Recommendation by Category-Aware Aesthetic Learning ABSTRACT: Nowadays, social media has become a popular platform for the public to share photos. To make photos more visually appealing, users usually apply filters on their photos without domain knowledge. However, due to the growing number of filter types, it becomes a major issue for users to choose the best filter type. For this purpose, filter recommendation for photo aesthetics takes an important role in image quality ranking problems. In these years, several works have declared that Convolutional Neural Networks (CNNs) outperform traditional methods in image aesthetic categorization, which classifies images into high or low quality. Most of them do not consider the effect on filtered images; hence, we propose a novel image aesthetic learning for filter recommendation. Instead of binarizing image quality, we adjust the state-of-the-art CNN architectures and design a pairwise loss function to learn the embedded aesthetic responses in hidden layers for filtered images. Based on our pilot study, we observe image categories (e.g., portrait, landscape, food) will affect user preference on filter selection. We further integrate category classification into our proposed aesthetic-oriented models. To the best of our knowledge, there is no public dataset for aesthetic judgment with filtered images. We create a new dataset called Filter Aesthetic Comparison Dataset (FACD). It contains 28,160 filtered images based on the AVA dataset and 42,240 reliable image pairs with aesthetic annotations using Amazon Mechanical Turk. It is the first dataset containing filtered images and user preference labels. We conduct experiments on the collected FACD for filter recommendation, and the results show that our proposed category-aware aesthetic learning outperforms aesthetic classification methods (e.g., 12% relative improvement).
new_dataset
0.965381
1610.04325
Jin-Hwa Kim
Jin-Hwa Kim, Kyoung-Woon On, Woosang Lim, Jeonghee Kim, Jung-Woo Ha, Byoung-Tak Zhang
Hadamard Product for Low-rank Bilinear Pooling
13 pages, 1 figure, & appendix. ICLR 2017 accepted
null
null
null
cs.CV cs.AI cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bilinear models provide rich representations compared with linear models. They have been applied in various visual tasks, such as object recognition, segmentation, and visual question-answering, to get state-of-the-art performances taking advantage of the expanded representations. However, bilinear representations tend to be high-dimensional, limiting the applicability to computationally complex tasks. We propose low-rank bilinear pooling using Hadamard product for an efficient attention mechanism of multimodal learning. We show that our model outperforms compact bilinear pooling in visual question-answering tasks with the state-of-the-art results on the VQA dataset, having a better parsimonious property.
[ { "version": "v1", "created": "Fri, 14 Oct 2016 04:29:52 GMT" }, { "version": "v2", "created": "Tue, 1 Nov 2016 05:31:27 GMT" }, { "version": "v3", "created": "Tue, 14 Feb 2017 05:22:01 GMT" }, { "version": "v4", "created": "Sun, 26 Mar 2017 16:22:47 GMT" } ]
2017-03-28T00:00:00
[ [ "Kim", "Jin-Hwa", "" ], [ "On", "Kyoung-Woon", "" ], [ "Lim", "Woosang", "" ], [ "Kim", "Jeonghee", "" ], [ "Ha", "Jung-Woo", "" ], [ "Zhang", "Byoung-Tak", "" ] ]
TITLE: Hadamard Product for Low-rank Bilinear Pooling ABSTRACT: Bilinear models provide rich representations compared with linear models. They have been applied in various visual tasks, such as object recognition, segmentation, and visual question-answering, to get state-of-the-art performances taking advantage of the expanded representations. However, bilinear representations tend to be high-dimensional, limiting the applicability to computationally complex tasks. We propose low-rank bilinear pooling using Hadamard product for an efficient attention mechanism of multimodal learning. We show that our model outperforms compact bilinear pooling in visual question-answering tasks with the state-of-the-art results on the VQA dataset, having a better parsimonious property.
no_new_dataset
0.948822
1610.07718
Jiecao Chen
Jiecao Chen and Qin Zhang
Bias-Aware Sketches
16 pages
null
null
null
cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Linear sketching algorithms have been widely used for processing large-scale distributed and streaming datasets. Their popularity is largely due to the fact that linear sketches can be naturally composed in the distributed model and be efficiently updated in the streaming model. The errors of linear sketches are typically expressed in terms of the sum of coordinates of the input vector excluding those largest ones, or, the mass on the tail of the vector. Thus, the precondition for these algorithms to perform well is that the mass on the tail is small, which is, however, not always the case -- in many real-world datasets the coordinates of the input vector have a {\em bias}, which will generate a large mass on the tail. In this paper we propose linear sketches that are {\em bias-aware}. We rigorously prove that they achieve strictly better error guarantees than the corresponding existing sketches, and demonstrate their practicality and superiority via an extensive experimental evaluation on both real and synthetic datasets.
[ { "version": "v1", "created": "Tue, 25 Oct 2016 03:51:39 GMT" }, { "version": "v2", "created": "Sun, 26 Mar 2017 19:17:54 GMT" } ]
2017-03-28T00:00:00
[ [ "Chen", "Jiecao", "" ], [ "Zhang", "Qin", "" ] ]
TITLE: Bias-Aware Sketches ABSTRACT: Linear sketching algorithms have been widely used for processing large-scale distributed and streaming datasets. Their popularity is largely due to the fact that linear sketches can be naturally composed in the distributed model and be efficiently updated in the streaming model. The errors of linear sketches are typically expressed in terms of the sum of coordinates of the input vector excluding those largest ones, or, the mass on the tail of the vector. Thus, the precondition for these algorithms to perform well is that the mass on the tail is small, which is, however, not always the case -- in many real-world datasets the coordinates of the input vector have a {\em bias}, which will generate a large mass on the tail. In this paper we propose linear sketches that are {\em bias-aware}. We rigorously prove that they achieve strictly better error guarantees than the corresponding existing sketches, and demonstrate their practicality and superiority via an extensive experimental evaluation on both real and synthetic datasets.
no_new_dataset
0.949248
1611.02364
Guillaume-Alexandre Bilodeau
Yuebin Yang, Guillaume-Alexandre Bilodeau
Multiple Object Tracking with Kernelized Correlation Filters in Urban Mixed Traffic
Accepted for CRV 2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently, the Kernelized Correlation Filters tracker (KCF) achieved competitive performance and robustness in visual object tracking. On the other hand, visual trackers are not typically used in multiple object tracking. In this paper, we investigate how a robust visual tracker like KCF can improve multiple object tracking. Since KCF is a fast tracker, many can be used in parallel and still result in fast tracking. We build a multiple object tracking system based on KCF and background subtraction. Background subtraction is applied to extract moving objects and get their scale and size in combination with KCF outputs, while KCF is used for data association and to handle fragmentation and occlusion problems. As a result, KCF and background subtraction help each other to take tracking decision at every frame. Sometimes KCF outputs are the most trustworthy (e.g. during occlusion), while in some other case, it is the background subtraction outputs. To validate the effectiveness of our system, the algorithm is demonstrated on four urban video recordings from a standard dataset. Results show that our method is competitive with state-of-the-art trackers even if we use a much simpler data association step.
[ { "version": "v1", "created": "Tue, 8 Nov 2016 02:20:09 GMT" }, { "version": "v2", "created": "Mon, 27 Mar 2017 14:36:59 GMT" } ]
2017-03-28T00:00:00
[ [ "Yang", "Yuebin", "" ], [ "Bilodeau", "Guillaume-Alexandre", "" ] ]
TITLE: Multiple Object Tracking with Kernelized Correlation Filters in Urban Mixed Traffic ABSTRACT: Recently, the Kernelized Correlation Filters tracker (KCF) achieved competitive performance and robustness in visual object tracking. On the other hand, visual trackers are not typically used in multiple object tracking. In this paper, we investigate how a robust visual tracker like KCF can improve multiple object tracking. Since KCF is a fast tracker, many can be used in parallel and still result in fast tracking. We build a multiple object tracking system based on KCF and background subtraction. Background subtraction is applied to extract moving objects and get their scale and size in combination with KCF outputs, while KCF is used for data association and to handle fragmentation and occlusion problems. As a result, KCF and background subtraction help each other to take tracking decision at every frame. Sometimes KCF outputs are the most trustworthy (e.g. during occlusion), while in some other case, it is the background subtraction outputs. To validate the effectiveness of our system, the algorithm is demonstrated on four urban video recordings from a standard dataset. Results show that our method is competitive with state-of-the-art trackers even if we use a much simpler data association step.
no_new_dataset
0.946745
1612.00089
Luka \v{C}ehovin
Luka \v{C}ehovin Zajc, Alan Luke\v{z}i\v{c}, Ale\v{s} Leonardis, Matej Kristan
Beyond standard benchmarks: Parameterizing performance evaluation in visual object tracking
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Object-to-camera motion produces a variety of apparent motion patterns that significantly affect performance of short-term visual trackers. Despite being crucial for designing robust trackers, their influence is poorly explored in standard benchmarks due to weakly defined, biased and overlapping attribute annotations. In this paper we propose to go beyond pre-recorded benchmarks with post-hoc annotations by presenting an approach that utilizes omnidirectional videos to generate realistic, consistently annotated, short-term tracking scenarios with exactly parameterized motion patterns. We have created an evaluation system, constructed a fully annotated dataset of omnidirectional videos and the generators for typical motion patterns. We provide an in-depth analysis of major tracking paradigms which is complementary to the standard benchmarks and confirms the expressiveness of our evaluation approach.
[ { "version": "v1", "created": "Thu, 1 Dec 2016 00:26:03 GMT" }, { "version": "v2", "created": "Sat, 25 Mar 2017 18:13:40 GMT" } ]
2017-03-28T00:00:00
[ [ "Zajc", "Luka Čehovin", "" ], [ "Lukežič", "Alan", "" ], [ "Leonardis", "Aleš", "" ], [ "Kristan", "Matej", "" ] ]
TITLE: Beyond standard benchmarks: Parameterizing performance evaluation in visual object tracking ABSTRACT: Object-to-camera motion produces a variety of apparent motion patterns that significantly affect performance of short-term visual trackers. Despite being crucial for designing robust trackers, their influence is poorly explored in standard benchmarks due to weakly defined, biased and overlapping attribute annotations. In this paper we propose to go beyond pre-recorded benchmarks with post-hoc annotations by presenting an approach that utilizes omnidirectional videos to generate realistic, consistently annotated, short-term tracking scenarios with exactly parameterized motion patterns. We have created an evaluation system, constructed a fully annotated dataset of omnidirectional videos and the generators for typical motion patterns. We provide an in-depth analysis of major tracking paradigms which is complementary to the standard benchmarks and confirms the expressiveness of our evaluation approach.
new_dataset
0.949763
1702.08234
Hamza Harkous
Hamza Harkous and Karl Aberer
"If You Can't Beat them, Join them": A Usability Approach to Interdependent Privacy in Cloud Apps
Authors' extended version of the paper published at CODASPY 2017
null
10.1145/3029806.3029837
null
cs.CR cs.HC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cloud storage services, like Dropbox and Google Drive, have growing ecosystems of 3rd party apps that are designed to work with users' cloud files. Such apps often request full access to users' files, including files shared with collaborators. Hence, whenever a user grants access to a new vendor, she is inflicting a privacy loss on herself and on her collaborators too. Based on analyzing a real dataset of 183 Google Drive users and 131 third party apps, we discover that collaborators inflict a privacy loss which is at least 39% higher than what users themselves cause. We take a step toward minimizing this loss by introducing the concept of History-based decisions. Simply put, users are informed at decision time about the vendors which have been previously granted access to their data. Thus, they can reduce their privacy loss by not installing apps from new vendors whenever possible. Next, we realize this concept by introducing a new privacy indicator, which can be integrated within the cloud apps' authorization interface. Via a web experiment with 141 participants recruited from CrowdFlower, we show that our privacy indicator can significantly increase the user's likelihood of choosing the app that minimizes her privacy loss. Finally, we explore the network effect of History-based decisions via a simulation on top of large collaboration networks. We demonstrate that adopting such a decision-making process is capable of reducing the growth of users' privacy loss by 70% in a Google Drive-based network and by 40% in an author collaboration network. This is despite the fact that we neither assume that users cooperate nor that they exhibit altruistic behavior. To our knowledge, our work is the first to provide quantifiable evidence of the privacy risk that collaborators pose in cloud apps. We are also the first to mitigate this problem via a usable privacy approach.
[ { "version": "v1", "created": "Mon, 27 Feb 2017 11:15:21 GMT" }, { "version": "v2", "created": "Fri, 24 Mar 2017 19:29:03 GMT" } ]
2017-03-28T00:00:00
[ [ "Harkous", "Hamza", "" ], [ "Aberer", "Karl", "" ] ]
TITLE: "If You Can't Beat them, Join them": A Usability Approach to Interdependent Privacy in Cloud Apps ABSTRACT: Cloud storage services, like Dropbox and Google Drive, have growing ecosystems of 3rd party apps that are designed to work with users' cloud files. Such apps often request full access to users' files, including files shared with collaborators. Hence, whenever a user grants access to a new vendor, she is inflicting a privacy loss on herself and on her collaborators too. Based on analyzing a real dataset of 183 Google Drive users and 131 third party apps, we discover that collaborators inflict a privacy loss which is at least 39% higher than what users themselves cause. We take a step toward minimizing this loss by introducing the concept of History-based decisions. Simply put, users are informed at decision time about the vendors which have been previously granted access to their data. Thus, they can reduce their privacy loss by not installing apps from new vendors whenever possible. Next, we realize this concept by introducing a new privacy indicator, which can be integrated within the cloud apps' authorization interface. Via a web experiment with 141 participants recruited from CrowdFlower, we show that our privacy indicator can significantly increase the user's likelihood of choosing the app that minimizes her privacy loss. Finally, we explore the network effect of History-based decisions via a simulation on top of large collaboration networks. We demonstrate that adopting such a decision-making process is capable of reducing the growth of users' privacy loss by 70% in a Google Drive-based network and by 40% in an author collaboration network. This is despite the fact that we neither assume that users cooperate nor that they exhibit altruistic behavior. To our knowledge, our work is the first to provide quantifiable evidence of the privacy risk that collaborators pose in cloud apps. We are also the first to mitigate this problem via a usable privacy approach.
no_new_dataset
0.939025
1702.08652
Pichao Wang
Pichao Wang and Wanqing Li and Zhimin Gao and Yuyao Zhang and Chang Tang and Philip Ogunbona
Scene Flow to Action Map: A New Representation for RGB-D based Action Recognition with Convolutional Neural Networks
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Scene flow describes the motion of 3D objects in real world and potentially could be the basis of a good feature for 3D action recognition. However, its use for action recognition, especially in the context of convolutional neural networks (ConvNets), has not been previously studied. In this paper, we propose the extraction and use of scene flow for action recognition from RGB-D data. Previous works have considered the depth and RGB modalities as separate channels and extract features for later fusion. We take a different approach and consider the modalities as one entity, thus allowing feature extraction for action recognition at the beginning. Two key questions about the use of scene flow for action recognition are addressed: how to organize the scene flow vectors and how to represent the long term dynamics of videos based on scene flow. In order to calculate the scene flow correctly on the available datasets, we propose an effective self-calibration method to align the RGB and depth data spatially without knowledge of the camera parameters. Based on the scene flow vectors, we propose a new representation, namely, Scene Flow to Action Map (SFAM), that describes several long term spatio-temporal dynamics for action recognition. We adopt a channel transform kernel to transform the scene flow vectors to an optimal color space analogous to RGB. This transformation takes better advantage of the trained ConvNets models over ImageNet. Experimental results indicate that this new representation can surpass the performance of state-of-the-art methods on two large public datasets.
[ { "version": "v1", "created": "Tue, 28 Feb 2017 05:39:25 GMT" }, { "version": "v2", "created": "Sat, 4 Mar 2017 07:33:51 GMT" }, { "version": "v3", "created": "Mon, 27 Mar 2017 00:52:21 GMT" } ]
2017-03-28T00:00:00
[ [ "Wang", "Pichao", "" ], [ "Li", "Wanqing", "" ], [ "Gao", "Zhimin", "" ], [ "Zhang", "Yuyao", "" ], [ "Tang", "Chang", "" ], [ "Ogunbona", "Philip", "" ] ]
TITLE: Scene Flow to Action Map: A New Representation for RGB-D based Action Recognition with Convolutional Neural Networks ABSTRACT: Scene flow describes the motion of 3D objects in real world and potentially could be the basis of a good feature for 3D action recognition. However, its use for action recognition, especially in the context of convolutional neural networks (ConvNets), has not been previously studied. In this paper, we propose the extraction and use of scene flow for action recognition from RGB-D data. Previous works have considered the depth and RGB modalities as separate channels and extract features for later fusion. We take a different approach and consider the modalities as one entity, thus allowing feature extraction for action recognition at the beginning. Two key questions about the use of scene flow for action recognition are addressed: how to organize the scene flow vectors and how to represent the long term dynamics of videos based on scene flow. In order to calculate the scene flow correctly on the available datasets, we propose an effective self-calibration method to align the RGB and depth data spatially without knowledge of the camera parameters. Based on the scene flow vectors, we propose a new representation, namely, Scene Flow to Action Map (SFAM), that describes several long term spatio-temporal dynamics for action recognition. We adopt a channel transform kernel to transform the scene flow vectors to an optimal color space analogous to RGB. This transformation takes better advantage of the trained ConvNets models over ImageNet. Experimental results indicate that this new representation can surpass the performance of state-of-the-art methods on two large public datasets.
no_new_dataset
0.949153
1703.03107
Onur Varol
Onur Varol, Emilio Ferrara, Clayton A. Davis, Filippo Menczer, Alessandro Flammini
Online Human-Bot Interactions: Detection, Estimation, and Characterization
Accepted paper for ICWSM'17, 10 pages, 8 figures, 1 table
null
null
null
cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Increasing evidence suggests that a growing amount of social media content is generated by autonomous entities known as social bots. In this work we present a framework to detect such entities on Twitter. We leverage more than a thousand features extracted from public data and meta-data about users: friends, tweet content and sentiment, network patterns, and activity time series. We benchmark the classification framework by using a publicly available dataset of Twitter bots. This training data is enriched by a manually annotated collection of active Twitter users that include both humans and bots of varying sophistication. Our models yield high accuracy and agreement with each other and can detect bots of different nature. Our estimates suggest that between 9% and 15% of active Twitter accounts are bots. Characterizing ties among accounts, we observe that simple bots tend to interact with bots that exhibit more human-like behaviors. Analysis of content flows reveals retweet and mention strategies adopted by bots to interact with different target groups. Using clustering analysis, we characterize several subclasses of accounts, including spammers, self promoters, and accounts that post content from connected applications.
[ { "version": "v1", "created": "Thu, 9 Mar 2017 02:27:47 GMT" }, { "version": "v2", "created": "Mon, 27 Mar 2017 17:56:11 GMT" } ]
2017-03-28T00:00:00
[ [ "Varol", "Onur", "" ], [ "Ferrara", "Emilio", "" ], [ "Davis", "Clayton A.", "" ], [ "Menczer", "Filippo", "" ], [ "Flammini", "Alessandro", "" ] ]
TITLE: Online Human-Bot Interactions: Detection, Estimation, and Characterization ABSTRACT: Increasing evidence suggests that a growing amount of social media content is generated by autonomous entities known as social bots. In this work we present a framework to detect such entities on Twitter. We leverage more than a thousand features extracted from public data and meta-data about users: friends, tweet content and sentiment, network patterns, and activity time series. We benchmark the classification framework by using a publicly available dataset of Twitter bots. This training data is enriched by a manually annotated collection of active Twitter users that include both humans and bots of varying sophistication. Our models yield high accuracy and agreement with each other and can detect bots of different nature. Our estimates suggest that between 9% and 15% of active Twitter accounts are bots. Characterizing ties among accounts, we observe that simple bots tend to interact with bots that exhibit more human-like behaviors. Analysis of content flows reveals retweet and mention strategies adopted by bots to interact with different target groups. Using clustering analysis, we characterize several subclasses of accounts, including spammers, self promoters, and accounts that post content from connected applications.
no_new_dataset
0.946646
1703.04617
Junbei Zhang
Junbei Zhang, Xiaodan Zhu, Qian Chen, Lirong Dai, Si Wei, and Hui Jiang
Exploring Question Understanding and Adaptation in Neural-Network-Based Question Answering
null
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The last several years have seen intensive interest in exploring neural-network-based models for machine comprehension (MC) and question answering (QA). In this paper, we approach the problems by closely modelling questions in a neural network framework. We first introduce syntactic information to help encode questions. We then view and model different types of questions and the information shared among them as an adaptation task and proposed adaptation models for them. On the Stanford Question Answering Dataset (SQuAD), we show that these approaches can help attain better results over a competitive baseline.
[ { "version": "v1", "created": "Tue, 14 Mar 2017 17:43:25 GMT" }, { "version": "v2", "created": "Sat, 25 Mar 2017 16:17:03 GMT" } ]
2017-03-28T00:00:00
[ [ "Zhang", "Junbei", "" ], [ "Zhu", "Xiaodan", "" ], [ "Chen", "Qian", "" ], [ "Dai", "Lirong", "" ], [ "Wei", "Si", "" ], [ "Jiang", "Hui", "" ] ]
TITLE: Exploring Question Understanding and Adaptation in Neural-Network-Based Question Answering ABSTRACT: The last several years have seen intensive interest in exploring neural-network-based models for machine comprehension (MC) and question answering (QA). In this paper, we approach the problems by closely modelling questions in a neural network framework. We first introduce syntactic information to help encode questions. We then view and model different types of questions and the information shared among them as an adaptation task and proposed adaptation models for them. On the Stanford Question Answering Dataset (SQuAD), we show that these approaches can help attain better results over a competitive baseline.
no_new_dataset
0.935405
1703.06412
Ayushman Dash
Ayushman Dash, John Cristian Borges Gamboa, Sheraz Ahmed, Marcus Liwicki, Muhammad Zeshan Afzal
TAC-GAN - Text Conditioned Auxiliary Classifier Generative Adversarial Network
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we present the Text Conditioned Auxiliary Classifier Generative Adversarial Network, (TAC-GAN) a text to image Generative Adversarial Network (GAN) for synthesizing images from their text descriptions. Former approaches have tried to condition the generative process on the textual data; but allying it to the usage of class information, known to diversify the generated samples and improve their structural coherence, has not been explored. We trained the presented TAC-GAN model on the Oxford-102 dataset of flowers, and evaluated the discriminability of the generated images with Inception-Score, as well as their diversity using the Multi-Scale Structural Similarity Index (MS-SSIM). Our approach outperforms the state-of-the-art models, i.e., its inception score is 3.45, corresponding to a relative increase of 7.8% compared to the recently introduced StackGan. A comparison of the mean MS-SSIM scores of the training and generated samples per class shows that our approach is able to generate highly diverse images with an average MS-SSIM of 0.14 over all generated classes.
[ { "version": "v1", "created": "Sun, 19 Mar 2017 10:07:58 GMT" }, { "version": "v2", "created": "Sun, 26 Mar 2017 11:29:21 GMT" } ]
2017-03-28T00:00:00
[ [ "Dash", "Ayushman", "" ], [ "Gamboa", "John Cristian Borges", "" ], [ "Ahmed", "Sheraz", "" ], [ "Liwicki", "Marcus", "" ], [ "Afzal", "Muhammad Zeshan", "" ] ]
TITLE: TAC-GAN - Text Conditioned Auxiliary Classifier Generative Adversarial Network ABSTRACT: In this work, we present the Text Conditioned Auxiliary Classifier Generative Adversarial Network, (TAC-GAN) a text to image Generative Adversarial Network (GAN) for synthesizing images from their text descriptions. Former approaches have tried to condition the generative process on the textual data; but allying it to the usage of class information, known to diversify the generated samples and improve their structural coherence, has not been explored. We trained the presented TAC-GAN model on the Oxford-102 dataset of flowers, and evaluated the discriminability of the generated images with Inception-Score, as well as their diversity using the Multi-Scale Structural Similarity Index (MS-SSIM). Our approach outperforms the state-of-the-art models, i.e., its inception score is 3.45, corresponding to a relative increase of 7.8% compared to the recently introduced StackGan. A comparison of the mean MS-SSIM scores of the training and generated samples per class shows that our approach is able to generate highly diverse images with an average MS-SSIM of 0.14 over all generated classes.
no_new_dataset
0.948965
1703.08580
Vittal Premachandran
Daniil Pakhomov and Vittal Premachandran and Max Allan and Mahdi Azizian and Nassir Navab
Deep Residual Learning for Instrument Segmentation in Robotic Surgery
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Detection, tracking, and pose estimation of surgical instruments are crucial tasks for computer assistance during minimally invasive robotic surgery. In the majority of cases, the first step is the automatic segmentation of surgical tools. Prior work has focused on binary segmentation, where the objective is to label every pixel in an image as tool or background. We improve upon previous work in two major ways. First, we leverage recent techniques such as deep residual learning and dilated convolutions to advance binary-segmentation performance. Second, we extend the approach to multi-class segmentation, which lets us segment different parts of the tool, in addition to background. We demonstrate the performance of this method on the MICCAI Endoscopic Vision Challenge Robotic Instruments dataset.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 19:43:20 GMT" } ]
2017-03-28T00:00:00
[ [ "Pakhomov", "Daniil", "" ], [ "Premachandran", "Vittal", "" ], [ "Allan", "Max", "" ], [ "Azizian", "Mahdi", "" ], [ "Navab", "Nassir", "" ] ]
TITLE: Deep Residual Learning for Instrument Segmentation in Robotic Surgery ABSTRACT: Detection, tracking, and pose estimation of surgical instruments are crucial tasks for computer assistance during minimally invasive robotic surgery. In the majority of cases, the first step is the automatic segmentation of surgical tools. Prior work has focused on binary segmentation, where the objective is to label every pixel in an image as tool or background. We improve upon previous work in two major ways. First, we leverage recent techniques such as deep residual learning and dilated convolutions to advance binary-segmentation performance. Second, we extend the approach to multi-class segmentation, which lets us segment different parts of the tool, in addition to background. We demonstrate the performance of this method on the MICCAI Endoscopic Vision Challenge Robotic Instruments dataset.
no_new_dataset
0.948917
1703.08617
Chi Nhan Duong
Chi Nhan Duong, Kha Gia Quach, Khoa Luu, T. Hoang Ngan le, Marios Savvides
Temporal Non-Volume Preserving Approach to Facial Age-Progression and Age-Invariant Face Recognition
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Modeling the long-term facial aging process is extremely challenging due to the presence of large and non-linear variations during the face development stages. In order to efficiently address the problem, this work first decomposes the aging process into multiple short-term stages. Then, a novel generative probabilistic model, named Temporal Non-Volume Preserving (TNVP) transformation, is presented to model the facial aging process at each stage. Unlike Generative Adversarial Networks (GANs), which requires an empirical balance threshold, and Restricted Boltzmann Machines (RBM), an intractable model, our proposed TNVP approach guarantees a tractable density function, exact inference and evaluation for embedding the feature transformations between faces in consecutive stages. Our model shows its advantages not only in capturing the non-linear age related variance in each stage but also producing a smooth synthesis in age progression across faces. Our approach can model any face in the wild provided with only four basic landmark points. Moreover, the structure can be transformed into a deep convolutional network while keeping the advantages of probabilistic models with tractable log-likelihood density estimation. Our method is evaluated in both terms of synthesizing age-progressed faces and cross-age face verification and consistently shows the state-of-the-art results in various face aging databases, i.e. FG-NET, MORPH, AginG Faces in the Wild (AGFW), and Cross-Age Celebrity Dataset (CACD). A large-scale face verification on Megaface challenge 1 is also performed to further show the advantages of our proposed approach.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 22:43:05 GMT" } ]
2017-03-28T00:00:00
[ [ "Duong", "Chi Nhan", "" ], [ "Quach", "Kha Gia", "" ], [ "Luu", "Khoa", "" ], [ "le", "T. Hoang Ngan", "" ], [ "Savvides", "Marios", "" ] ]
TITLE: Temporal Non-Volume Preserving Approach to Facial Age-Progression and Age-Invariant Face Recognition ABSTRACT: Modeling the long-term facial aging process is extremely challenging due to the presence of large and non-linear variations during the face development stages. In order to efficiently address the problem, this work first decomposes the aging process into multiple short-term stages. Then, a novel generative probabilistic model, named Temporal Non-Volume Preserving (TNVP) transformation, is presented to model the facial aging process at each stage. Unlike Generative Adversarial Networks (GANs), which requires an empirical balance threshold, and Restricted Boltzmann Machines (RBM), an intractable model, our proposed TNVP approach guarantees a tractable density function, exact inference and evaluation for embedding the feature transformations between faces in consecutive stages. Our model shows its advantages not only in capturing the non-linear age related variance in each stage but also producing a smooth synthesis in age progression across faces. Our approach can model any face in the wild provided with only four basic landmark points. Moreover, the structure can be transformed into a deep convolutional network while keeping the advantages of probabilistic models with tractable log-likelihood density estimation. Our method is evaluated in both terms of synthesizing age-progressed faces and cross-age face verification and consistently shows the state-of-the-art results in various face aging databases, i.e. FG-NET, MORPH, AginG Faces in the Wild (AGFW), and Cross-Age Celebrity Dataset (CACD). A large-scale face verification on Megaface challenge 1 is also performed to further show the advantages of our proposed approach.
no_new_dataset
0.947575
1703.08668
Dong Wen
Dong Wen, Lu Qin, Xuemin Lin, Ying Zhang, Lijun Chang
Enumerating k-Vertex Connected Components in Large Graphs
16 pages
null
null
null
cs.DB cs.SI
http://creativecommons.org/licenses/by/4.0/
Cohesive subgraph detection is an important graph problem that is widely applied in many application domains, such as social community detection, network visualization, and network topology analysis. Most of existing cohesive subgraph metrics can guarantee good structural properties but may cause the free-rider effect. Here, by free-rider effect, we mean that some irrelevant subgraphs are combined as one subgraph if they only share a small number of vertices and edges. In this paper, we study k-vertex connected component (k-VCC) which can effectively eliminate the free-rider effect but less studied in the literature. A k-VCC is a connected subgraph in which the removal of any k-1 vertices will not disconnect the subgraph. In addition to eliminating the free-rider effect, k-VCC also has other advantages such as bounded diameter, high cohesiveness, bounded graph overlapping, and bounded subgraph number. We propose a polynomial time algorithm to enumerate all k-VCCs of a graph by recursively partitioning the graph into overlapped subgraphs. We find that the key to improving the algorithm is reducing the number of local connectivity testings. Therefore, we propose two effective optimization strategies, namely neighbor sweep and group sweep, to largely reduce the number of local connectivity testings. We conduct extensive performance studies using seven large real datasets to demonstrate the effectiveness of this model as well as the efficiency of our proposed algorithms.
[ { "version": "v1", "created": "Sat, 25 Mar 2017 09:36:47 GMT" } ]
2017-03-28T00:00:00
[ [ "Wen", "Dong", "" ], [ "Qin", "Lu", "" ], [ "Lin", "Xuemin", "" ], [ "Zhang", "Ying", "" ], [ "Chang", "Lijun", "" ] ]
TITLE: Enumerating k-Vertex Connected Components in Large Graphs ABSTRACT: Cohesive subgraph detection is an important graph problem that is widely applied in many application domains, such as social community detection, network visualization, and network topology analysis. Most of existing cohesive subgraph metrics can guarantee good structural properties but may cause the free-rider effect. Here, by free-rider effect, we mean that some irrelevant subgraphs are combined as one subgraph if they only share a small number of vertices and edges. In this paper, we study k-vertex connected component (k-VCC) which can effectively eliminate the free-rider effect but less studied in the literature. A k-VCC is a connected subgraph in which the removal of any k-1 vertices will not disconnect the subgraph. In addition to eliminating the free-rider effect, k-VCC also has other advantages such as bounded diameter, high cohesiveness, bounded graph overlapping, and bounded subgraph number. We propose a polynomial time algorithm to enumerate all k-VCCs of a graph by recursively partitioning the graph into overlapped subgraphs. We find that the key to improving the algorithm is reducing the number of local connectivity testings. Therefore, we propose two effective optimization strategies, namely neighbor sweep and group sweep, to largely reduce the number of local connectivity testings. We conduct extensive performance studies using seven large real datasets to demonstrate the effectiveness of this model as well as the efficiency of our proposed algorithms.
no_new_dataset
0.943191
1703.08701
Albert Gatt
Claudia Borg and Albert Gatt
Morphological Analysis for the Maltese Language: The Challenges of a Hybrid System
11pages, Proceedings of the 3rd Arabic Natural Language Processing Workshop (WANLP'17)
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Maltese is a morphologically rich language with a hybrid morphological system which features both concatenative and non-concatenative processes. This paper analyses the impact of this hybridity on the performance of machine learning techniques for morphological labelling and clustering. In particular, we analyse a dataset of morphologically related word clusters to evaluate the difference in results for concatenative and nonconcatenative clusters. We also describe research carried out in morphological labelling, with a particular focus on the verb category. Two evaluations were carried out, one using an unseen dataset, and another one using a gold standard dataset which was manually labelled. The gold standard dataset was split into concatenative and non-concatenative to analyse the difference in results between the two morphological systems.
[ { "version": "v1", "created": "Sat, 25 Mar 2017 14:56:27 GMT" } ]
2017-03-28T00:00:00
[ [ "Borg", "Claudia", "" ], [ "Gatt", "Albert", "" ] ]
TITLE: Morphological Analysis for the Maltese Language: The Challenges of a Hybrid System ABSTRACT: Maltese is a morphologically rich language with a hybrid morphological system which features both concatenative and non-concatenative processes. This paper analyses the impact of this hybridity on the performance of machine learning techniques for morphological labelling and clustering. In particular, we analyse a dataset of morphologically related word clusters to evaluate the difference in results for concatenative and nonconcatenative clusters. We also describe research carried out in morphological labelling, with a particular focus on the verb category. Two evaluations were carried out, one using an unseen dataset, and another one using a gold standard dataset which was manually labelled. The gold standard dataset was split into concatenative and non-concatenative to analyse the difference in results between the two morphological systems.
no_new_dataset
0.82226
1703.08762
Sanaz Bahargam Sanaz Bahargam
Sanaz Bahargam, D\'ora Erdos, Azer Bestavros, Evimaria Terzi
Team Formation for Scheduling Educational Material in Massive Online Classes
null
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Whether teaching in a classroom or a Massive Online Open Course it is crucial to present the material in a way that benefits the audience as a whole. We identify two important tasks to solve towards this objective, 1 group students so that they can maximally benefit from peer interaction and 2 find an optimal schedule of the educational material for each group. Thus, in this paper, we solve the problem of team formation and content scheduling for education. Given a time frame d, a set of students S with their required need to learn different activities T and given k as the number of desired groups, we study the problem of finding k group of students. The goal is to teach students within time frame d such that their potential for learning is maximized and find the best schedule for each group. We show this problem to be NP-hard and develop a polynomial algorithm for it. We show our algorithm to be effective both on synthetic as well as a real data set. For our experiments, we use real data on students' grades in a Computer Science department. As part of our contribution, we release a semi-synthetic dataset that mimics the properties of the real data.
[ { "version": "v1", "created": "Sun, 26 Mar 2017 03:47:54 GMT" } ]
2017-03-28T00:00:00
[ [ "Bahargam", "Sanaz", "" ], [ "Erdos", "Dóra", "" ], [ "Bestavros", "Azer", "" ], [ "Terzi", "Evimaria", "" ] ]
TITLE: Team Formation for Scheduling Educational Material in Massive Online Classes ABSTRACT: Whether teaching in a classroom or a Massive Online Open Course it is crucial to present the material in a way that benefits the audience as a whole. We identify two important tasks to solve towards this objective, 1 group students so that they can maximally benefit from peer interaction and 2 find an optimal schedule of the educational material for each group. Thus, in this paper, we solve the problem of team formation and content scheduling for education. Given a time frame d, a set of students S with their required need to learn different activities T and given k as the number of desired groups, we study the problem of finding k group of students. The goal is to teach students within time frame d such that their potential for learning is maximized and find the best schedule for each group. We show this problem to be NP-hard and develop a polynomial algorithm for it. We show our algorithm to be effective both on synthetic as well as a real data set. For our experiments, we use real data on students' grades in a Computer Science department. As part of our contribution, we release a semi-synthetic dataset that mimics the properties of the real data.
new_dataset
0.960731
1703.08764
Chunhua Shen
Fayao Liu, Guosheng Lin, Ruizhi Qiao, Chunhua Shen
Structured Learning of Tree Potentials in CRF for Image Segmentation
10 pages. Appearing in IEEE Transactions on Neural Networks and Learning Systems
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a new approach to image segmentation, which exploits the advantages of both conditional random fields (CRFs) and decision trees. In the literature, the potential functions of CRFs are mostly defined as a linear combination of some pre-defined parametric models, and then methods like structured support vector machines (SSVMs) are applied to learn those linear coefficients. We instead formulate the unary and pairwise potentials as nonparametric forests---ensembles of decision trees, and learn the ensemble parameters and the trees in a unified optimization problem within the large-margin framework. In this fashion, we easily achieve nonlinear learning of potential functions on both unary and pairwise terms in CRFs. Moreover, we learn class-wise decision trees for each object that appears in the image. Due to the rich structure and flexibility of decision trees, our approach is powerful in modelling complex data likelihoods and label relationships. The resulting optimization problem is very challenging because it can have exponentially many variables and constraints. We show that this challenging optimization can be efficiently solved by combining a modified column generation and cutting-planes techniques. Experimental results on both binary (Graz-02, Weizmann horse, Oxford flower) and multi-class (MSRC-21, PASCAL VOC 2012) segmentation datasets demonstrate the power of the learned nonlinear nonparametric potentials.
[ { "version": "v1", "created": "Sun, 26 Mar 2017 04:15:10 GMT" } ]
2017-03-28T00:00:00
[ [ "Liu", "Fayao", "" ], [ "Lin", "Guosheng", "" ], [ "Qiao", "Ruizhi", "" ], [ "Shen", "Chunhua", "" ] ]
TITLE: Structured Learning of Tree Potentials in CRF for Image Segmentation ABSTRACT: We propose a new approach to image segmentation, which exploits the advantages of both conditional random fields (CRFs) and decision trees. In the literature, the potential functions of CRFs are mostly defined as a linear combination of some pre-defined parametric models, and then methods like structured support vector machines (SSVMs) are applied to learn those linear coefficients. We instead formulate the unary and pairwise potentials as nonparametric forests---ensembles of decision trees, and learn the ensemble parameters and the trees in a unified optimization problem within the large-margin framework. In this fashion, we easily achieve nonlinear learning of potential functions on both unary and pairwise terms in CRFs. Moreover, we learn class-wise decision trees for each object that appears in the image. Due to the rich structure and flexibility of decision trees, our approach is powerful in modelling complex data likelihoods and label relationships. The resulting optimization problem is very challenging because it can have exponentially many variables and constraints. We show that this challenging optimization can be efficiently solved by combining a modified column generation and cutting-planes techniques. Experimental results on both binary (Graz-02, Weizmann horse, Oxford flower) and multi-class (MSRC-21, PASCAL VOC 2012) segmentation datasets demonstrate the power of the learned nonlinear nonparametric potentials.
no_new_dataset
0.950411
1703.08885
Yusuke Watanabe Dr.
Yusuke Watanabe, Bhuwan Dhingra, Ruslan Salakhutdinov
Question Answering from Unstructured Text by Retrieval and Comprehension
null
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Open domain Question Answering (QA) systems must interact with external knowledge sources, such as web pages, to find relevant information. Information sources like Wikipedia, however, are not well structured and difficult to utilize in comparison with Knowledge Bases (KBs). In this work we present a two-step approach to question answering from unstructured text, consisting of a retrieval step and a comprehension step. For comprehension, we present an RNN based attention model with a novel mixture mechanism for selecting answers from either retrieved articles or a fixed vocabulary. For retrieval we introduce a hand-crafted model and a neural model for ranking relevant articles. We achieve state-of-the-art performance on W IKI M OVIES dataset, reducing the error by 40%. Our experimental results further demonstrate the importance of each of the introduced components.
[ { "version": "v1", "created": "Sun, 26 Mar 2017 23:48:06 GMT" } ]
2017-03-28T00:00:00
[ [ "Watanabe", "Yusuke", "" ], [ "Dhingra", "Bhuwan", "" ], [ "Salakhutdinov", "Ruslan", "" ] ]
TITLE: Question Answering from Unstructured Text by Retrieval and Comprehension ABSTRACT: Open domain Question Answering (QA) systems must interact with external knowledge sources, such as web pages, to find relevant information. Information sources like Wikipedia, however, are not well structured and difficult to utilize in comparison with Knowledge Bases (KBs). In this work we present a two-step approach to question answering from unstructured text, consisting of a retrieval step and a comprehension step. For comprehension, we present an RNN based attention model with a novel mixture mechanism for selecting answers from either retrieved articles or a fixed vocabulary. For retrieval we introduce a hand-crafted model and a neural model for ranking relevant articles. We achieve state-of-the-art performance on W IKI M OVIES dataset, reducing the error by 40%. Our experimental results further demonstrate the importance of each of the introduced components.
no_new_dataset
0.947527
1703.08893
Yunlong Yu
Yunlong Yu, Zhong Ji, Xi Li, Jichang Guo, Zhongfei Zhang, Haibin Ling, Fei Wu
Transductive Zero-Shot Learning with a Self-training dictionary approach
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
As an important and challenging problem in computer vision, zero-shot learning (ZSL) aims at automatically recognizing the instances from unseen object classes without training data. To address this problem, ZSL is usually carried out in the following two aspects: 1) capturing the domain distribution connections between seen classes data and unseen classes data; and 2) modeling the semantic interactions between the image feature space and the label embedding space. Motivated by these observations, we propose a bidirectional mapping based semantic relationship modeling scheme that seeks for crossmodal knowledge transfer by simultaneously projecting the image features and label embeddings into a common latent space. Namely, we have a bidirectional connection relationship that takes place from the image feature space to the latent space as well as from the label embedding space to the latent space. To deal with the domain shift problem, we further present a transductive learning approach that formulates the class prediction problem in an iterative refining process, where the object classification capacity is progressively reinforced through bootstrapping-based model updating over highly reliable instances. Experimental results on three benchmark datasets (AwA, CUB and SUN) demonstrate the effectiveness of the proposed approach against the state-of-the-art approaches.
[ { "version": "v1", "created": "Mon, 27 Mar 2017 01:36:38 GMT" } ]
2017-03-28T00:00:00
[ [ "Yu", "Yunlong", "" ], [ "Ji", "Zhong", "" ], [ "Li", "Xi", "" ], [ "Guo", "Jichang", "" ], [ "Zhang", "Zhongfei", "" ], [ "Ling", "Haibin", "" ], [ "Wu", "Fei", "" ] ]
TITLE: Transductive Zero-Shot Learning with a Self-training dictionary approach ABSTRACT: As an important and challenging problem in computer vision, zero-shot learning (ZSL) aims at automatically recognizing the instances from unseen object classes without training data. To address this problem, ZSL is usually carried out in the following two aspects: 1) capturing the domain distribution connections between seen classes data and unseen classes data; and 2) modeling the semantic interactions between the image feature space and the label embedding space. Motivated by these observations, we propose a bidirectional mapping based semantic relationship modeling scheme that seeks for crossmodal knowledge transfer by simultaneously projecting the image features and label embeddings into a common latent space. Namely, we have a bidirectional connection relationship that takes place from the image feature space to the latent space as well as from the label embedding space to the latent space. To deal with the domain shift problem, we further present a transductive learning approach that formulates the class prediction problem in an iterative refining process, where the object classification capacity is progressively reinforced through bootstrapping-based model updating over highly reliable instances. Experimental results on three benchmark datasets (AwA, CUB and SUN) demonstrate the effectiveness of the proposed approach against the state-of-the-art approaches.
no_new_dataset
0.946597
1703.08897
Yunlong Yu
Yunlong Yu, Zhong Ji, Jichang Guo, and Yanwei Pang
Transductive Zero-Shot Learning with Adaptive Structural Embedding
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Zero-shot learning (ZSL) endows the computer vision system with the inferential capability to recognize instances of a new category that has never seen before. Two fundamental challenges in it are visual-semantic embedding and domain adaptation in cross-modality learning and unseen class prediction steps, respectively. To address both challenges, this paper presents two corresponding methods named Adaptive STructural Embedding (ASTE) and Self-PAsed Selective Strategy (SPASS), respectively. Specifically, ASTE formulates the visualsemantic interactions in a latent structural SVM framework to adaptively adjust the slack variables to embody the different reliableness among training instances. In this way, the reliable instances are imposed with small punishments, wheras the less reliable instances are imposed with more severe punishments. Thus, it ensures a more discriminative embedding. On the other hand, SPASS offers a framework to alleviate the domain shift problem in ZSL, which exploits the unseen data in an easy to hard fashion. Particularly, SPASS borrows the idea from selfpaced learning by iteratively selecting the unseen instances from reliable to less reliable to gradually adapt the knowledge from the seen domain to the unseen domain. Subsequently, by combining SPASS and ASTE, we present a self-paced Transductive ASTE (TASTE) method to progressively reinforce the classification capacity. Extensive experiments on three benchmark datasets (i.e., AwA, CUB, and aPY) demonstrate the superiorities of ASTE and TASTE. Furthermore, we also propose a fast training (FT) strategy to improve the efficiency of most of existing ZSL methods. The FT strategy is surprisingly simple and general enough, which can speed up the training time of most existing methods by 4~300 times while holding the previous performance.
[ { "version": "v1", "created": "Mon, 27 Mar 2017 01:44:41 GMT" } ]
2017-03-28T00:00:00
[ [ "Yu", "Yunlong", "" ], [ "Ji", "Zhong", "" ], [ "Guo", "Jichang", "" ], [ "Pang", "Yanwei", "" ] ]
TITLE: Transductive Zero-Shot Learning with Adaptive Structural Embedding ABSTRACT: Zero-shot learning (ZSL) endows the computer vision system with the inferential capability to recognize instances of a new category that has never seen before. Two fundamental challenges in it are visual-semantic embedding and domain adaptation in cross-modality learning and unseen class prediction steps, respectively. To address both challenges, this paper presents two corresponding methods named Adaptive STructural Embedding (ASTE) and Self-PAsed Selective Strategy (SPASS), respectively. Specifically, ASTE formulates the visualsemantic interactions in a latent structural SVM framework to adaptively adjust the slack variables to embody the different reliableness among training instances. In this way, the reliable instances are imposed with small punishments, wheras the less reliable instances are imposed with more severe punishments. Thus, it ensures a more discriminative embedding. On the other hand, SPASS offers a framework to alleviate the domain shift problem in ZSL, which exploits the unseen data in an easy to hard fashion. Particularly, SPASS borrows the idea from selfpaced learning by iteratively selecting the unseen instances from reliable to less reliable to gradually adapt the knowledge from the seen domain to the unseen domain. Subsequently, by combining SPASS and ASTE, we present a self-paced Transductive ASTE (TASTE) method to progressively reinforce the classification capacity. Extensive experiments on three benchmark datasets (i.e., AwA, CUB, and aPY) demonstrate the superiorities of ASTE and TASTE. Furthermore, we also propose a fast training (FT) strategy to improve the efficiency of most of existing ZSL methods. The FT strategy is surprisingly simple and general enough, which can speed up the training time of most existing methods by 4~300 times while holding the previous performance.
no_new_dataset
0.946794
1703.09076
Yunho Jeon
Yunho Jeon, Junmo Kim
Active Convolution: Learning the Shape of Convolution for Image Classification
Accepted to appear in CVPR 2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years, deep learning has achieved great success in many computer vision applications. Convolutional neural networks (CNNs) have lately emerged as a major approach to image classification. Most research on CNNs thus far has focused on developing architectures such as the Inception and residual networks. The convolution layer is the core of the CNN, but few studies have addressed the convolution unit itself. In this paper, we introduce a convolution unit called the active convolution unit (ACU). A new convolution has no fixed shape, because of which we can define any form of convolution. Its shape can be learned through backpropagation during training. Our proposed unit has a few advantages. First, the ACU is a generalization of convolution; it can define not only all conventional convolutions, but also convolutions with fractional pixel coordinates. We can freely change the shape of the convolution, which provides greater freedom to form CNN structures. Second, the shape of the convolution is learned while training and there is no need to tune it by hand. Third, the ACU can learn better than a conventional unit, where we obtained the improvement simply by changing the conventional convolution to an ACU. We tested our proposed method on plain and residual networks, and the results showed significant improvement using our method on various datasets and architectures in comparison with the baseline.
[ { "version": "v1", "created": "Mon, 27 Mar 2017 13:44:26 GMT" } ]
2017-03-28T00:00:00
[ [ "Jeon", "Yunho", "" ], [ "Kim", "Junmo", "" ] ]
TITLE: Active Convolution: Learning the Shape of Convolution for Image Classification ABSTRACT: In recent years, deep learning has achieved great success in many computer vision applications. Convolutional neural networks (CNNs) have lately emerged as a major approach to image classification. Most research on CNNs thus far has focused on developing architectures such as the Inception and residual networks. The convolution layer is the core of the CNN, but few studies have addressed the convolution unit itself. In this paper, we introduce a convolution unit called the active convolution unit (ACU). A new convolution has no fixed shape, because of which we can define any form of convolution. Its shape can be learned through backpropagation during training. Our proposed unit has a few advantages. First, the ACU is a generalization of convolution; it can define not only all conventional convolutions, but also convolutions with fractional pixel coordinates. We can freely change the shape of the convolution, which provides greater freedom to form CNN structures. Second, the shape of the convolution is learned while training and there is no need to tune it by hand. Third, the ACU can learn better than a conventional unit, where we obtained the improvement simply by changing the conventional convolution to an ACU. We tested our proposed method on plain and residual networks, and the results showed significant improvement using our method on various datasets and architectures in comparison with the baseline.
no_new_dataset
0.951142
1703.09145
Yuguang Liu
Yuguang Liu, Martin D. Levine
Multi-Path Region-Based Convolutional Neural Network for Accurate Detection of Unconstrained "Hard Faces"
11 pages, 7 figures, to be presented at CRV 2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Large-scale variations still pose a challenge in unconstrained face detection. To the best of our knowledge, no current face detection algorithm can detect a face as large as 800 x 800 pixels while simultaneously detecting another one as small as 8 x 8 pixels within a single image with equally high accuracy. We propose a two-stage cascaded face detection framework, Multi-Path Region-based Convolutional Neural Network (MP-RCNN), that seamlessly combines a deep neural network with a classic learning strategy, to tackle this challenge. The first stage is a Multi-Path Region Proposal Network (MP-RPN) that proposes faces at three different scales. It simultaneously utilizes three parallel outputs of the convolutional feature maps to predict multi-scale candidate face regions. The "atrous" convolution trick (convolution with up-sampled filters) and a newly proposed sampling layer for "hard" examples are embedded in MP-RPN to further boost its performance. The second stage is a Boosted Forests classifier, which utilizes deep facial features pooled from inside the candidate face regions as well as deep contextual features pooled from a larger region surrounding the candidate face regions. This step is included to further remove hard negative samples. Experiments show that this approach achieves state-of-the-art face detection performance on the WIDER FACE dataset "hard" partition, outperforming the former best result by 9.6% for the Average Precision.
[ { "version": "v1", "created": "Mon, 27 Mar 2017 15:31:00 GMT" } ]
2017-03-28T00:00:00
[ [ "Liu", "Yuguang", "" ], [ "Levine", "Martin D.", "" ] ]
TITLE: Multi-Path Region-Based Convolutional Neural Network for Accurate Detection of Unconstrained "Hard Faces" ABSTRACT: Large-scale variations still pose a challenge in unconstrained face detection. To the best of our knowledge, no current face detection algorithm can detect a face as large as 800 x 800 pixels while simultaneously detecting another one as small as 8 x 8 pixels within a single image with equally high accuracy. We propose a two-stage cascaded face detection framework, Multi-Path Region-based Convolutional Neural Network (MP-RCNN), that seamlessly combines a deep neural network with a classic learning strategy, to tackle this challenge. The first stage is a Multi-Path Region Proposal Network (MP-RPN) that proposes faces at three different scales. It simultaneously utilizes three parallel outputs of the convolutional feature maps to predict multi-scale candidate face regions. The "atrous" convolution trick (convolution with up-sampled filters) and a newly proposed sampling layer for "hard" examples are embedded in MP-RPN to further boost its performance. The second stage is a Boosted Forests classifier, which utilizes deep facial features pooled from inside the candidate face regions as well as deep contextual features pooled from a larger region surrounding the candidate face regions. This step is included to further remove hard negative samples. Experiments show that this approach achieves state-of-the-art face detection performance on the WIDER FACE dataset "hard" partition, outperforming the former best result by 9.6% for the Average Precision.
no_new_dataset
0.948155
1703.09193
Saravanan Thirumuruganathan
Zoi Kaoudi, Jorge-Arnulfo Quian\'e-Ruiz, Saravanan Thirumuruganathan, Sanjay Chawla, Divy Agrawal
A Cost-based Optimizer for Gradient Descent Optimization
Accepted at SIGMOD 2017
null
10.1145/3035918.3064042
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
As the use of machine learning (ML) permeates into diverse application domains, there is an urgent need to support a declarative framework for ML. Ideally, a user will specify an ML task in a high-level and easy-to-use language and the framework will invoke the appropriate algorithms and system configurations to execute it. An important observation towards designing such a framework is that many ML tasks can be expressed as mathematical optimization problems, which take a specific form. Furthermore, these optimization problems can be efficiently solved using variations of the gradient descent (GD) algorithm. Thus, to decouple a user specification of an ML task from its execution, a key component is a GD optimizer. We propose a cost-based GD optimizer that selects the best GD plan for a given ML task. To build our optimizer, we introduce a set of abstract operators for expressing GD algorithms and propose a novel approach to estimate the number of iterations a GD algorithm requires to converge. Extensive experiments on real and synthetic datasets show that our optimizer not only chooses the best GD plan but also allows for optimizations that achieve orders of magnitude performance speed-up.
[ { "version": "v1", "created": "Mon, 27 Mar 2017 17:24:54 GMT" } ]
2017-03-28T00:00:00
[ [ "Kaoudi", "Zoi", "" ], [ "Quiané-Ruiz", "Jorge-Arnulfo", "" ], [ "Thirumuruganathan", "Saravanan", "" ], [ "Chawla", "Sanjay", "" ], [ "Agrawal", "Divy", "" ] ]
TITLE: A Cost-based Optimizer for Gradient Descent Optimization ABSTRACT: As the use of machine learning (ML) permeates into diverse application domains, there is an urgent need to support a declarative framework for ML. Ideally, a user will specify an ML task in a high-level and easy-to-use language and the framework will invoke the appropriate algorithms and system configurations to execute it. An important observation towards designing such a framework is that many ML tasks can be expressed as mathematical optimization problems, which take a specific form. Furthermore, these optimization problems can be efficiently solved using variations of the gradient descent (GD) algorithm. Thus, to decouple a user specification of an ML task from its execution, a key component is a GD optimizer. We propose a cost-based GD optimizer that selects the best GD plan for a given ML task. To build our optimizer, we introduce a set of abstract operators for expressing GD algorithms and propose a novel approach to estimate the number of iterations a GD algorithm requires to converge. Extensive experiments on real and synthetic datasets show that our optimizer not only chooses the best GD plan but also allows for optimizations that achieve orders of magnitude performance speed-up.
no_new_dataset
0.938463
1612.07056
Panayiotis Varotsos
Panayiotis A. Varotsos, Nicholas V. Sarlis, Efthimios S. Skordas and Mary S. Lazaridou
Seismic Electric Signals: A physical interconnection with seismicity
18 pages, 8 figures, 1 table
null
null
null
physics.geo-ph cond-mat.stat-mech
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
By applying natural time analysis to the time series of earthquakes, we find that the order parameter of seismicity exhibits a unique change approximately at the date(s) at which Seismic Electric Signals (SES) activities have been reported to initiate. In particular, we show that the fluctuations of the order parameter of seismicity in Japan exhibits a clearly detectable minimum approximately at the time of the initiation of the SES activity observed almost two months before the onset of the Volcanic-seismic swarm activity in 2000 in the Izu Island region, Japan. To the best of our knowledge, this is the first time that, well before the occurrence of major earthquakes, anomalous changes are found to appear almost simultaneously in two independent datasets of different geophysical observables (geoelectrical measurements, seismicity). In addition, we show that these two phenomena are also linked closely in space.
[ { "version": "v1", "created": "Wed, 21 Dec 2016 11:15:40 GMT" }, { "version": "v2", "created": "Fri, 24 Mar 2017 14:57:07 GMT" } ]
2017-03-27T00:00:00
[ [ "Varotsos", "Panayiotis A.", "" ], [ "Sarlis", "Nicholas V.", "" ], [ "Skordas", "Efthimios S.", "" ], [ "Lazaridou", "Mary S.", "" ] ]
TITLE: Seismic Electric Signals: A physical interconnection with seismicity ABSTRACT: By applying natural time analysis to the time series of earthquakes, we find that the order parameter of seismicity exhibits a unique change approximately at the date(s) at which Seismic Electric Signals (SES) activities have been reported to initiate. In particular, we show that the fluctuations of the order parameter of seismicity in Japan exhibits a clearly detectable minimum approximately at the time of the initiation of the SES activity observed almost two months before the onset of the Volcanic-seismic swarm activity in 2000 in the Izu Island region, Japan. To the best of our knowledge, this is the first time that, well before the occurrence of major earthquakes, anomalous changes are found to appear almost simultaneously in two independent datasets of different geophysical observables (geoelectrical measurements, seismicity). In addition, we show that these two phenomena are also linked closely in space.
no_new_dataset
0.952309
1703.07022
Xiaodan Liang
Xiaodan Liang, Zhiting Hu, Hao Zhang, Chuang Gan, Eric P. Xing
Recurrent Topic-Transition GAN for Visual Paragraph Generation
10 pages, 6 figures
null
null
null
cs.CV cs.AI cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A natural image usually conveys rich semantic content and can be viewed from different angles. Existing image description methods are largely restricted by small sets of biased visual paragraph annotations, and fail to cover rich underlying semantics. In this paper, we investigate a semi-supervised paragraph generative framework that is able to synthesize diverse and semantically coherent paragraph descriptions by reasoning over local semantic regions and exploiting linguistic knowledge. The proposed Recurrent Topic-Transition Generative Adversarial Network (RTT-GAN) builds an adversarial framework between a structured paragraph generator and multi-level paragraph discriminators. The paragraph generator generates sentences recurrently by incorporating region-based visual and language attention mechanisms at each step. The quality of generated paragraph sentences is assessed by multi-level adversarial discriminators from two aspects, namely, plausibility at sentence level and topic-transition coherence at paragraph level. The joint adversarial training of RTT-GAN drives the model to generate realistic paragraphs with smooth logical transition between sentence topics. Extensive quantitative experiments on image and video paragraph datasets demonstrate the effectiveness of our RTT-GAN in both supervised and semi-supervised settings. Qualitative results on telling diverse stories for an image also verify the interpretability of RTT-GAN.
[ { "version": "v1", "created": "Tue, 21 Mar 2017 01:43:12 GMT" }, { "version": "v2", "created": "Thu, 23 Mar 2017 20:06:15 GMT" } ]
2017-03-27T00:00:00
[ [ "Liang", "Xiaodan", "" ], [ "Hu", "Zhiting", "" ], [ "Zhang", "Hao", "" ], [ "Gan", "Chuang", "" ], [ "Xing", "Eric P.", "" ] ]
TITLE: Recurrent Topic-Transition GAN for Visual Paragraph Generation ABSTRACT: A natural image usually conveys rich semantic content and can be viewed from different angles. Existing image description methods are largely restricted by small sets of biased visual paragraph annotations, and fail to cover rich underlying semantics. In this paper, we investigate a semi-supervised paragraph generative framework that is able to synthesize diverse and semantically coherent paragraph descriptions by reasoning over local semantic regions and exploiting linguistic knowledge. The proposed Recurrent Topic-Transition Generative Adversarial Network (RTT-GAN) builds an adversarial framework between a structured paragraph generator and multi-level paragraph discriminators. The paragraph generator generates sentences recurrently by incorporating region-based visual and language attention mechanisms at each step. The quality of generated paragraph sentences is assessed by multi-level adversarial discriminators from two aspects, namely, plausibility at sentence level and topic-transition coherence at paragraph level. The joint adversarial training of RTT-GAN drives the model to generate realistic paragraphs with smooth logical transition between sentence topics. Extensive quantitative experiments on image and video paragraph datasets demonstrate the effectiveness of our RTT-GAN in both supervised and semi-supervised settings. Qualitative results on telling diverse stories for an image also verify the interpretability of RTT-GAN.
no_new_dataset
0.946448
1703.08014
Timo von Marcard
Timo von Marcard, Bodo Rosenhahn, Michael J. Black, Gerard Pons-Moll
Sparse Inertial Poser: Automatic 3D Human Pose Estimation from Sparse IMUs
12 pages, Accepted at Eurographics 2017
null
null
null
cs.CV cs.GR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We address the problem of making human motion capture in the wild more practical by using a small set of inertial sensors attached to the body. Since the problem is heavily under-constrained, previous methods either use a large number of sensors, which is intrusive, or they require additional video input. We take a different approach and constrain the problem by: (i) making use of a realistic statistical body model that includes anthropometric constraints and (ii) using a joint optimization framework to fit the model to orientation and acceleration measurements over multiple frames. The resulting tracker Sparse Inertial Poser (SIP) enables 3D human pose estimation using only 6 sensors (attached to the wrists, lower legs, back and head) and works for arbitrary human motions. Experiments on the recently released TNT15 dataset show that, using the same number of sensors, SIP achieves higher accuracy than the dataset baseline without using any video data. We further demonstrate the effectiveness of SIP on newly recorded challenging motions in outdoor scenarios such as climbing or jumping over a wall.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 11:35:41 GMT" }, { "version": "v2", "created": "Fri, 24 Mar 2017 08:24:07 GMT" } ]
2017-03-27T00:00:00
[ [ "von Marcard", "Timo", "" ], [ "Rosenhahn", "Bodo", "" ], [ "Black", "Michael J.", "" ], [ "Pons-Moll", "Gerard", "" ] ]
TITLE: Sparse Inertial Poser: Automatic 3D Human Pose Estimation from Sparse IMUs ABSTRACT: We address the problem of making human motion capture in the wild more practical by using a small set of inertial sensors attached to the body. Since the problem is heavily under-constrained, previous methods either use a large number of sensors, which is intrusive, or they require additional video input. We take a different approach and constrain the problem by: (i) making use of a realistic statistical body model that includes anthropometric constraints and (ii) using a joint optimization framework to fit the model to orientation and acceleration measurements over multiple frames. The resulting tracker Sparse Inertial Poser (SIP) enables 3D human pose estimation using only 6 sensors (attached to the wrists, lower legs, back and head) and works for arbitrary human motions. Experiments on the recently released TNT15 dataset show that, using the same number of sensors, SIP achieves higher accuracy than the dataset baseline without using any video data. We further demonstrate the effectiveness of SIP on newly recorded challenging motions in outdoor scenarios such as climbing or jumping over a wall.
no_new_dataset
0.719433
1703.08244
Maribel Acosta
Fabian Fl\"ock, Kenan Erdogan, Maribel Acosta
TokTrack: A Complete Token Provenance and Change Tracking Dataset for the English Wikipedia
null
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a dataset that contains every instance of all tokens (~ words) ever written in undeleted, non-redirect English Wikipedia articles until October 2016, in total 13,545,349,787 instances. Each token is annotated with (i) the article revision it was originally created in, and (ii) lists with all the revisions in which the token was ever deleted and (potentially) re-added and re-deleted from its article, enabling a complete and straightforward tracking of its history. This data would be exceedingly hard to create by an average potential user as it is (i) very expensive to compute and as (ii) accurately tracking the history of each token in revisioned documents is a non-trivial task. Adapting a state-of-the-art algorithm, we have produced a dataset that allows for a range of analyses and metrics, already popular in research and going beyond, to be generated on complete-Wikipedia scale; ensuring quality and allowing researchers to forego expensive text-comparison computation, which so far has hindered scalable usage. We show how this data enables, on token-level, computation of provenance, measuring survival of content over time, very detailed conflict metrics, and fine-grained interactions of editors like partial reverts, re-additions and other metrics, in the process gaining several novel insights.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 22:20:45 GMT" } ]
2017-03-27T00:00:00
[ [ "Flöck", "Fabian", "" ], [ "Erdogan", "Kenan", "" ], [ "Acosta", "Maribel", "" ] ]
TITLE: TokTrack: A Complete Token Provenance and Change Tracking Dataset for the English Wikipedia ABSTRACT: We present a dataset that contains every instance of all tokens (~ words) ever written in undeleted, non-redirect English Wikipedia articles until October 2016, in total 13,545,349,787 instances. Each token is annotated with (i) the article revision it was originally created in, and (ii) lists with all the revisions in which the token was ever deleted and (potentially) re-added and re-deleted from its article, enabling a complete and straightforward tracking of its history. This data would be exceedingly hard to create by an average potential user as it is (i) very expensive to compute and as (ii) accurately tracking the history of each token in revisioned documents is a non-trivial task. Adapting a state-of-the-art algorithm, we have produced a dataset that allows for a range of analyses and metrics, already popular in research and going beyond, to be generated on complete-Wikipedia scale; ensuring quality and allowing researchers to forego expensive text-comparison computation, which so far has hindered scalable usage. We show how this data enables, on token-level, computation of provenance, measuring survival of content over time, very detailed conflict metrics, and fine-grained interactions of editors like partial reverts, re-additions and other metrics, in the process gaining several novel insights.
new_dataset
0.964355
1703.08289
Wenhao He
Wenhao He, Xu-Yao Zhang, Fei Yin, Cheng-Lin Liu
Deep Direct Regression for Multi-Oriented Scene Text Detection
9 pages, 9 figures
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we first provide a new perspective to divide existing high performance object detection methods into direct and indirect regressions. Direct regression performs boundary regression by predicting the offsets from a given point, while indirect regression predicts the offsets from some bounding box proposals. Then we analyze the drawbacks of the indirect regression, which the recent state-of-the-art detection structures like Faster-RCNN and SSD follows, for multi-oriented scene text detection, and point out the potential superiority of direct regression. To verify this point of view, we propose a deep direct regression based method for multi-oriented scene text detection. Our detection framework is simple and effective with a fully convolutional network and one-step post processing. The fully convolutional network is optimized in an end-to-end way and has bi-task outputs where one is pixel-wise classification between text and non-text, and the other is direct regression to determine the vertex coordinates of quadrilateral text boundaries. The proposed method is particularly beneficial for localizing incidental scene texts. On the ICDAR2015 Incidental Scene Text benchmark, our method achieves the F1-measure of 81%, which is a new state-of-the-art and significantly outperforms previous approaches. On other standard datasets with focused scene texts, our method also reaches the state-of-the-art performance.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 05:54:11 GMT" } ]
2017-03-27T00:00:00
[ [ "He", "Wenhao", "" ], [ "Zhang", "Xu-Yao", "" ], [ "Yin", "Fei", "" ], [ "Liu", "Cheng-Lin", "" ] ]
TITLE: Deep Direct Regression for Multi-Oriented Scene Text Detection ABSTRACT: In this paper, we first provide a new perspective to divide existing high performance object detection methods into direct and indirect regressions. Direct regression performs boundary regression by predicting the offsets from a given point, while indirect regression predicts the offsets from some bounding box proposals. Then we analyze the drawbacks of the indirect regression, which the recent state-of-the-art detection structures like Faster-RCNN and SSD follows, for multi-oriented scene text detection, and point out the potential superiority of direct regression. To verify this point of view, we propose a deep direct regression based method for multi-oriented scene text detection. Our detection framework is simple and effective with a fully convolutional network and one-step post processing. The fully convolutional network is optimized in an end-to-end way and has bi-task outputs where one is pixel-wise classification between text and non-text, and the other is direct regression to determine the vertex coordinates of quadrilateral text boundaries. The proposed method is particularly beneficial for localizing incidental scene texts. On the ICDAR2015 Incidental Scene Text benchmark, our method achieves the F1-measure of 81%, which is a new state-of-the-art and significantly outperforms previous approaches. On other standard datasets with focused scene texts, our method also reaches the state-of-the-art performance.
no_new_dataset
0.947624
1703.08366
Mohamed Moustafa
Hussein Adly and Mohamed Moustafa
A Hybrid Deep Learning Approach for Texture Analysis
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Texture classification is a problem that has various applications such as remote sensing and forest species recognition. Solutions tend to be custom fit to the dataset used but fails to generalize. The Convolutional Neural Network (CNN) in combination with Support Vector Machine (SVM) form a robust selection between powerful invariant feature extractor and accurate classifier. The fusion of experts provides stability in classification rates among different datasets.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 11:39:26 GMT" } ]
2017-03-27T00:00:00
[ [ "Adly", "Hussein", "" ], [ "Moustafa", "Mohamed", "" ] ]
TITLE: A Hybrid Deep Learning Approach for Texture Analysis ABSTRACT: Texture classification is a problem that has various applications such as remote sensing and forest species recognition. Solutions tend to be custom fit to the dataset used but fails to generalize. The Convolutional Neural Network (CNN) in combination with Support Vector Machine (SVM) form a robust selection between powerful invariant feature extractor and accurate classifier. The fusion of experts provides stability in classification rates among different datasets.
no_new_dataset
0.954137
1703.08378
Shenglan Liu
Shenglan Liu, Muxin Sun, Wei Wang, Feilong Wang
Feature Fusion using Extended Jaccard Graph and Stochastic Gradient Descent for Robot
Assembly Automation
null
null
null
cs.CV cs.LG cs.RO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Robot vision is a fundamental device for human-robot interaction and robot complex tasks. In this paper, we use Kinect and propose a feature graph fusion (FGF) for robot recognition. Our feature fusion utilizes RGB and depth information to construct fused feature from Kinect. FGF involves multi-Jaccard similarity to compute a robust graph and utilize word embedding method to enhance the recognition results. We also collect DUT RGB-D face dataset and a benchmark datset to evaluate the effectiveness and efficiency of our method. The experimental results illustrate FGF is robust and effective to face and object datasets in robot applications.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 11:58:14 GMT" } ]
2017-03-27T00:00:00
[ [ "Liu", "Shenglan", "" ], [ "Sun", "Muxin", "" ], [ "Wang", "Wei", "" ], [ "Wang", "Feilong", "" ] ]
TITLE: Feature Fusion using Extended Jaccard Graph and Stochastic Gradient Descent for Robot ABSTRACT: Robot vision is a fundamental device for human-robot interaction and robot complex tasks. In this paper, we use Kinect and propose a feature graph fusion (FGF) for robot recognition. Our feature fusion utilizes RGB and depth information to construct fused feature from Kinect. FGF involves multi-Jaccard similarity to compute a robust graph and utilize word embedding method to enhance the recognition results. We also collect DUT RGB-D face dataset and a benchmark datset to evaluate the effectiveness and efficiency of our method. The experimental results illustrate FGF is robust and effective to face and object datasets in robot applications.
no_new_dataset
0.724139
1703.08434
Kojo Sarfo Gyamfi
Kojo Sarfo Gyamfi, James Brusey, Andrew Hunt and Elena Gaura
Linear classifier design under heteroscedasticity in Linear Discriminant Analysis
null
null
10.1016/j.eswa.2017.02.039
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Under normality and homoscedasticity assumptions, Linear Discriminant Analysis (LDA) is known to be optimal in terms of minimising the Bayes error for binary classification. In the heteroscedastic case, LDA is not guaranteed to minimise this error. Assuming heteroscedasticity, we derive a linear classifier, the Gaussian Linear Discriminant (GLD), that directly minimises the Bayes error for binary classification. In addition, we also propose a local neighbourhood search (LNS) algorithm to obtain a more robust classifier if the data is known to have a non-normal distribution. We evaluate the proposed classifiers on two artificial and ten real-world datasets that cut across a wide range of application areas including handwriting recognition, medical diagnosis and remote sensing, and then compare our algorithm against existing LDA approaches and other linear classifiers. The GLD is shown to outperform the original LDA procedure in terms of the classification accuracy under heteroscedasticity. While it compares favourably with other existing heteroscedastic LDA approaches, the GLD requires as much as 60 times lower training time on some datasets. Our comparison with the support vector machine (SVM) also shows that, the GLD, together with the LNS, requires as much as 150 times lower training time to achieve an equivalent classification accuracy on some of the datasets. Thus, our algorithms can provide a cheap and reliable option for classification in a lot of expert systems.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 14:45:12 GMT" } ]
2017-03-27T00:00:00
[ [ "Gyamfi", "Kojo Sarfo", "" ], [ "Brusey", "James", "" ], [ "Hunt", "Andrew", "" ], [ "Gaura", "Elena", "" ] ]
TITLE: Linear classifier design under heteroscedasticity in Linear Discriminant Analysis ABSTRACT: Under normality and homoscedasticity assumptions, Linear Discriminant Analysis (LDA) is known to be optimal in terms of minimising the Bayes error for binary classification. In the heteroscedastic case, LDA is not guaranteed to minimise this error. Assuming heteroscedasticity, we derive a linear classifier, the Gaussian Linear Discriminant (GLD), that directly minimises the Bayes error for binary classification. In addition, we also propose a local neighbourhood search (LNS) algorithm to obtain a more robust classifier if the data is known to have a non-normal distribution. We evaluate the proposed classifiers on two artificial and ten real-world datasets that cut across a wide range of application areas including handwriting recognition, medical diagnosis and remote sensing, and then compare our algorithm against existing LDA approaches and other linear classifiers. The GLD is shown to outperform the original LDA procedure in terms of the classification accuracy under heteroscedasticity. While it compares favourably with other existing heteroscedastic LDA approaches, the GLD requires as much as 60 times lower training time on some datasets. Our comparison with the support vector machine (SVM) also shows that, the GLD, together with the LNS, requires as much as 150 times lower training time to achieve an equivalent classification accuracy on some of the datasets. Thus, our algorithms can provide a cheap and reliable option for classification in a lot of expert systems.
no_new_dataset
0.946101
1703.08440
Kojo Sarfo Gyamfi
Kojo Sarfo Gyamfi, James Brusey and Andrew Hunt
K-Means Clustering using Tabu Search with Quantized Means
World Conference on Engineering and Computer Science
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Tabu Search (TS) metaheuristic has been proposed for K-Means clustering as an alternative to Lloyd's algorithm, which for all its ease of implementation and fast runtime, has the major drawback of being trapped at local optima. While the TS approach can yield superior performance, it involves a high computational complexity. Moreover, the difficulty in parameter selection in the existing TS approach does not make it any more attractive. This paper presents an alternative, low-complexity formulation of the TS optimization procedure for K-Means clustering. This approach does not require many parameter settings. We initially constrain the centers to points in the dataset. We then aim at evolving these centers using a unique neighborhood structure that makes use of gradient information of the objective function. This results in an efficient exploration of the search space, after which the means are refined. The proposed scheme is implemented in MATLAB and tested on four real-world datasets, and it achieves a significant improvement over the existing TS approach in terms of the intra cluster sum of squares and computational time.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 14:59:06 GMT" } ]
2017-03-27T00:00:00
[ [ "Gyamfi", "Kojo Sarfo", "" ], [ "Brusey", "James", "" ], [ "Hunt", "Andrew", "" ] ]
TITLE: K-Means Clustering using Tabu Search with Quantized Means ABSTRACT: The Tabu Search (TS) metaheuristic has been proposed for K-Means clustering as an alternative to Lloyd's algorithm, which for all its ease of implementation and fast runtime, has the major drawback of being trapped at local optima. While the TS approach can yield superior performance, it involves a high computational complexity. Moreover, the difficulty in parameter selection in the existing TS approach does not make it any more attractive. This paper presents an alternative, low-complexity formulation of the TS optimization procedure for K-Means clustering. This approach does not require many parameter settings. We initially constrain the centers to points in the dataset. We then aim at evolving these centers using a unique neighborhood structure that makes use of gradient information of the objective function. This results in an efficient exploration of the search space, after which the means are refined. The proposed scheme is implemented in MATLAB and tested on four real-world datasets, and it achieves a significant improvement over the existing TS approach in terms of the intra cluster sum of squares and computational time.
no_new_dataset
0.952309
1703.08471
Mirco Ravanelli
Mirco Ravanelli, Philemon Brakel, Maurizio Omologo, Yoshua Bengio
Batch-normalized joint training for DNN-based distant speech recognition
arXiv admin note: text overlap with arXiv:1703.08002
null
null
null
cs.CL cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Improving distant speech recognition is a crucial step towards flexible human-machine interfaces. Current technology, however, still exhibits a lack of robustness, especially when adverse acoustic conditions are met. Despite the significant progress made in the last years on both speech enhancement and speech recognition, one potential limitation of state-of-the-art technology lies in composing modules that are not well matched because they are not trained jointly. To address this concern, a promising approach consists in concatenating a speech enhancement and a speech recognition deep neural network and to jointly update their parameters as if they were within a single bigger network. Unfortunately, joint training can be difficult because the output distribution of the speech enhancement system may change substantially during the optimization procedure. The speech recognition module would have to deal with an input distribution that is non-stationary and unnormalized. To mitigate this issue, we propose a joint training approach based on a fully batch-normalized architecture. Experiments, conducted using different datasets, tasks and acoustic conditions, revealed that the proposed framework significantly overtakes other competitive solutions, especially in challenging environments.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 15:40:19 GMT" } ]
2017-03-27T00:00:00
[ [ "Ravanelli", "Mirco", "" ], [ "Brakel", "Philemon", "" ], [ "Omologo", "Maurizio", "" ], [ "Bengio", "Yoshua", "" ] ]
TITLE: Batch-normalized joint training for DNN-based distant speech recognition ABSTRACT: Improving distant speech recognition is a crucial step towards flexible human-machine interfaces. Current technology, however, still exhibits a lack of robustness, especially when adverse acoustic conditions are met. Despite the significant progress made in the last years on both speech enhancement and speech recognition, one potential limitation of state-of-the-art technology lies in composing modules that are not well matched because they are not trained jointly. To address this concern, a promising approach consists in concatenating a speech enhancement and a speech recognition deep neural network and to jointly update their parameters as if they were within a single bigger network. Unfortunately, joint training can be difficult because the output distribution of the speech enhancement system may change substantially during the optimization procedure. The speech recognition module would have to deal with an input distribution that is non-stationary and unnormalized. To mitigate this issue, we propose a joint training approach based on a fully batch-normalized architecture. Experiments, conducted using different datasets, tasks and acoustic conditions, revealed that the proposed framework significantly overtakes other competitive solutions, especially in challenging environments.
no_new_dataset
0.932699
1703.08524
Shuai Xiao
Shuai Xiao, Junchi Yan, Mehrdad Farajtabar, Le Song, Xiaokang Yang, Hongyuan Zha
Joint Modeling of Event Sequence and Time Series with Attentional Twin Recurrent Neural Networks
14 pages
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A variety of real-world processes (over networks) produce sequences of data whose complex temporal dynamics need to be studied. More especially, the event timestamps can carry important information about the underlying network dynamics, which otherwise are not available from the time-series evenly sampled from continuous signals. Moreover, in most complex processes, event sequences and evenly-sampled times series data can interact with each other, which renders joint modeling of those two sources of data necessary. To tackle the above problems, in this paper, we utilize the rich framework of (temporal) point processes to model event data and timely update its intensity function by the synergic twin Recurrent Neural Networks (RNNs). In the proposed architecture, the intensity function is synergistically modulated by one RNN with asynchronous events as input and another RNN with time series as input. Furthermore, to enhance the interpretability of the model, the attention mechanism for the neural point process is introduced. The whole model with event type and timestamp prediction output layers can be trained end-to-end and allows a black-box treatment for modeling the intensity. We substantiate the superiority of our model in synthetic data and three real-world benchmark datasets.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 17:29:14 GMT" } ]
2017-03-27T00:00:00
[ [ "Xiao", "Shuai", "" ], [ "Yan", "Junchi", "" ], [ "Farajtabar", "Mehrdad", "" ], [ "Song", "Le", "" ], [ "Yang", "Xiaokang", "" ], [ "Zha", "Hongyuan", "" ] ]
TITLE: Joint Modeling of Event Sequence and Time Series with Attentional Twin Recurrent Neural Networks ABSTRACT: A variety of real-world processes (over networks) produce sequences of data whose complex temporal dynamics need to be studied. More especially, the event timestamps can carry important information about the underlying network dynamics, which otherwise are not available from the time-series evenly sampled from continuous signals. Moreover, in most complex processes, event sequences and evenly-sampled times series data can interact with each other, which renders joint modeling of those two sources of data necessary. To tackle the above problems, in this paper, we utilize the rich framework of (temporal) point processes to model event data and timely update its intensity function by the synergic twin Recurrent Neural Networks (RNNs). In the proposed architecture, the intensity function is synergistically modulated by one RNN with asynchronous events as input and another RNN with time series as input. Furthermore, to enhance the interpretability of the model, the attention mechanism for the neural point process is introduced. The whole model with event type and timestamp prediction output layers can be trained end-to-end and allows a black-box treatment for modeling the intensity. We substantiate the superiority of our model in synthetic data and three real-world benchmark datasets.
no_new_dataset
0.953579
1508.03422
Salman Khan Mr.
Salman H. Khan, Munawar Hayat, Mohammed Bennamoun, Ferdous Sohel, Roberto Togneri
Cost Sensitive Learning of Deep Feature Representations from Imbalanced Data
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Class imbalance is a common problem in the case of real-world object detection and classification tasks. Data of some classes is abundant making them an over-represented majority, and data of other classes is scarce, making them an under-represented minority. This imbalance makes it challenging for a classifier to appropriately learn the discriminating boundaries of the majority and minority classes. In this work, we propose a cost sensitive deep neural network which can automatically learn robust feature representations for both the majority and minority classes. During training, our learning procedure jointly optimizes the class dependent costs and the neural network parameters. The proposed approach is applicable to both binary and multi-class problems without any modification. Moreover, as opposed to data level approaches, we do not alter the original data distribution which results in a lower computational cost during the training process. We report the results of our experiments on six major image classification datasets and show that the proposed approach significantly outperforms the baseline algorithms. Comparisons with popular data sampling techniques and cost sensitive classifiers demonstrate the superior performance of our proposed method.
[ { "version": "v1", "created": "Fri, 14 Aug 2015 05:23:30 GMT" }, { "version": "v2", "created": "Tue, 8 Dec 2015 08:37:37 GMT" }, { "version": "v3", "created": "Thu, 23 Mar 2017 10:57:10 GMT" } ]
2017-03-24T00:00:00
[ [ "Khan", "Salman H.", "" ], [ "Hayat", "Munawar", "" ], [ "Bennamoun", "Mohammed", "" ], [ "Sohel", "Ferdous", "" ], [ "Togneri", "Roberto", "" ] ]
TITLE: Cost Sensitive Learning of Deep Feature Representations from Imbalanced Data ABSTRACT: Class imbalance is a common problem in the case of real-world object detection and classification tasks. Data of some classes is abundant making them an over-represented majority, and data of other classes is scarce, making them an under-represented minority. This imbalance makes it challenging for a classifier to appropriately learn the discriminating boundaries of the majority and minority classes. In this work, we propose a cost sensitive deep neural network which can automatically learn robust feature representations for both the majority and minority classes. During training, our learning procedure jointly optimizes the class dependent costs and the neural network parameters. The proposed approach is applicable to both binary and multi-class problems without any modification. Moreover, as opposed to data level approaches, we do not alter the original data distribution which results in a lower computational cost during the training process. We report the results of our experiments on six major image classification datasets and show that the proposed approach significantly outperforms the baseline algorithms. Comparisons with popular data sampling techniques and cost sensitive classifiers demonstrate the superior performance of our proposed method.
no_new_dataset
0.951684
1606.03956
Eric Tramel
Eric W. Tramel and Andre Manoel and Francesco Caltagirone and Marylou Gabri\'e and Florent Krzakala
Inferring Sparsity: Compressed Sensing using Generalized Restricted Boltzmann Machines
IEEE Information Theory Workshop, 2016
2016 IEEE Information Theory Workshop (ITW), Pages: 265 - 269
10.1109/ITW.2016.7606837
null
cs.IT cond-mat.dis-nn cs.LG math.IT stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work, we consider compressed sensing reconstruction from $M$ measurements of $K$-sparse structured signals which do not possess a writable correlation model. Assuming that a generative statistical model, such as a Boltzmann machine, can be trained in an unsupervised manner on example signals, we demonstrate how this signal model can be used within a Bayesian framework of signal reconstruction. By deriving a message-passing inference for general distribution restricted Boltzmann machines, we are able to integrate these inferred signal models into approximate message passing for compressed sensing reconstruction. Finally, we show for the MNIST dataset that this approach can be very effective, even for $M < K$.
[ { "version": "v1", "created": "Mon, 13 Jun 2016 14:03:50 GMT" } ]
2017-03-24T00:00:00
[ [ "Tramel", "Eric W.", "" ], [ "Manoel", "Andre", "" ], [ "Caltagirone", "Francesco", "" ], [ "Gabrié", "Marylou", "" ], [ "Krzakala", "Florent", "" ] ]
TITLE: Inferring Sparsity: Compressed Sensing using Generalized Restricted Boltzmann Machines ABSTRACT: In this work, we consider compressed sensing reconstruction from $M$ measurements of $K$-sparse structured signals which do not possess a writable correlation model. Assuming that a generative statistical model, such as a Boltzmann machine, can be trained in an unsupervised manner on example signals, we demonstrate how this signal model can be used within a Bayesian framework of signal reconstruction. By deriving a message-passing inference for general distribution restricted Boltzmann machines, we are able to integrate these inferred signal models into approximate message passing for compressed sensing reconstruction. Finally, we show for the MNIST dataset that this approach can be very effective, even for $M < K$.
no_new_dataset
0.949669
1606.04722
Xi Wu
Xi Wu, Fengan Li, Arun Kumar, Kamalika Chaudhuri, Somesh Jha, Jeffrey F. Naughton
Bolt-on Differential Privacy for Scalable Stochastic Gradient Descent-based Analytics
null
null
null
null
cs.LG cs.CR cs.DB stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
While significant progress has been made separately on analytics systems for scalable stochastic gradient descent (SGD) and private SGD, none of the major scalable analytics frameworks have incorporated differentially private SGD. There are two inter-related issues for this disconnect between research and practice: (1) low model accuracy due to added noise to guarantee privacy, and (2) high development and runtime overhead of the private algorithms. This paper takes a first step to remedy this disconnect and proposes a private SGD algorithm to address \emph{both} issues in an integrated manner. In contrast to the white-box approach adopted by previous work, we revisit and use the classical technique of {\em output perturbation} to devise a novel "bolt-on" approach to private SGD. While our approach trivially addresses (2), it makes (1) even more challenging. We address this challenge by providing a novel analysis of the $L_2$-sensitivity of SGD, which allows, under the same privacy guarantees, better convergence of SGD when only a constant number of passes can be made over the data. We integrate our algorithm, as well as other state-of-the-art differentially private SGD, into Bismarck, a popular scalable SGD-based analytics system on top of an RDBMS. Extensive experiments show that our algorithm can be easily integrated, incurs virtually no overhead, scales well, and most importantly, yields substantially better (up to 4X) test accuracy than the state-of-the-art algorithms on many real datasets.
[ { "version": "v1", "created": "Wed, 15 Jun 2016 11:14:29 GMT" }, { "version": "v2", "created": "Sun, 26 Feb 2017 16:26:59 GMT" }, { "version": "v3", "created": "Thu, 23 Mar 2017 17:35:09 GMT" } ]
2017-03-24T00:00:00
[ [ "Wu", "Xi", "" ], [ "Li", "Fengan", "" ], [ "Kumar", "Arun", "" ], [ "Chaudhuri", "Kamalika", "" ], [ "Jha", "Somesh", "" ], [ "Naughton", "Jeffrey F.", "" ] ]
TITLE: Bolt-on Differential Privacy for Scalable Stochastic Gradient Descent-based Analytics ABSTRACT: While significant progress has been made separately on analytics systems for scalable stochastic gradient descent (SGD) and private SGD, none of the major scalable analytics frameworks have incorporated differentially private SGD. There are two inter-related issues for this disconnect between research and practice: (1) low model accuracy due to added noise to guarantee privacy, and (2) high development and runtime overhead of the private algorithms. This paper takes a first step to remedy this disconnect and proposes a private SGD algorithm to address \emph{both} issues in an integrated manner. In contrast to the white-box approach adopted by previous work, we revisit and use the classical technique of {\em output perturbation} to devise a novel "bolt-on" approach to private SGD. While our approach trivially addresses (2), it makes (1) even more challenging. We address this challenge by providing a novel analysis of the $L_2$-sensitivity of SGD, which allows, under the same privacy guarantees, better convergence of SGD when only a constant number of passes can be made over the data. We integrate our algorithm, as well as other state-of-the-art differentially private SGD, into Bismarck, a popular scalable SGD-based analytics system on top of an RDBMS. Extensive experiments show that our algorithm can be easily integrated, incurs virtually no overhead, scales well, and most importantly, yields substantially better (up to 4X) test accuracy than the state-of-the-art algorithms on many real datasets.
no_new_dataset
0.943295
1608.00161
Nam Vo
Nam Vo and James Hays
Localizing and Orienting Street Views Using Overhead Imagery
ECCV 2016
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we aim to determine the location and orientation of a ground-level query image by matching to a reference database of overhead (e.g. satellite) images. For this task we collect a new dataset with one million pairs of street view and overhead images sampled from eleven U.S. cities. We explore several deep CNN architectures for cross-domain matching -- Classification, Hybrid, Siamese, and Triplet networks. Classification and Hybrid architectures are accurate but slow since they allow only partial feature precomputation. We propose a new loss function which significantly improves the accuracy of Siamese and Triplet embedding networks while maintaining their applicability to large-scale retrieval tasks like image geolocalization. This image matching task is challenging not just because of the dramatic viewpoint difference between ground-level and overhead imagery but because the orientation (i.e. azimuth) of the street views is unknown making correspondence even more difficult. We examine several mechanisms to match in spite of this -- training for rotation invariance, sampling possible rotations at query time, and explicitly predicting relative rotation of ground and overhead images with our deep networks. It turns out that explicit orientation supervision also improves location prediction accuracy. Our best performing architectures are roughly 2.5 times as accurate as the commonly used Siamese network baseline.
[ { "version": "v1", "created": "Sat, 30 Jul 2016 20:48:14 GMT" }, { "version": "v2", "created": "Wed, 22 Mar 2017 23:49:57 GMT" } ]
2017-03-24T00:00:00
[ [ "Vo", "Nam", "" ], [ "Hays", "James", "" ] ]
TITLE: Localizing and Orienting Street Views Using Overhead Imagery ABSTRACT: In this paper we aim to determine the location and orientation of a ground-level query image by matching to a reference database of overhead (e.g. satellite) images. For this task we collect a new dataset with one million pairs of street view and overhead images sampled from eleven U.S. cities. We explore several deep CNN architectures for cross-domain matching -- Classification, Hybrid, Siamese, and Triplet networks. Classification and Hybrid architectures are accurate but slow since they allow only partial feature precomputation. We propose a new loss function which significantly improves the accuracy of Siamese and Triplet embedding networks while maintaining their applicability to large-scale retrieval tasks like image geolocalization. This image matching task is challenging not just because of the dramatic viewpoint difference between ground-level and overhead imagery but because the orientation (i.e. azimuth) of the street views is unknown making correspondence even more difficult. We examine several mechanisms to match in spite of this -- training for rotation invariance, sampling possible rotations at query time, and explicitly predicting relative rotation of ground and overhead images with our deep networks. It turns out that explicit orientation supervision also improves location prediction accuracy. Our best performing architectures are roughly 2.5 times as accurate as the commonly used Siamese network baseline.
new_dataset
0.956145
1611.06492
Abhinav Agarwalla
Arnav Kumar Jain, Abhinav Agarwalla, Kumar Krishna Agrawal, Pabitra Mitra
Recurrent Memory Addressing for describing videos
null
null
null
null
cs.CV cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we introduce Key-Value Memory Networks to a multimodal setting and a novel key-addressing mechanism to deal with sequence-to-sequence models. The proposed model naturally decomposes the problem of video captioning into vision and language segments, dealing with them as key-value pairs. More specifically, we learn a semantic embedding (v) corresponding to each frame (k) in the video, thereby creating (k, v) memory slots. We propose to find the next step attention weights conditioned on the previous attention distributions for the key-value memory slots in the memory addressing schema. Exploiting this flexibility of the framework, we additionally capture spatial dependencies while mapping from the visual to semantic embedding. Experiments done on the Youtube2Text dataset demonstrate usefulness of recurrent key-addressing, while achieving competitive scores on BLEU@4, METEOR metrics against state-of-the-art models.
[ { "version": "v1", "created": "Sun, 20 Nov 2016 10:07:54 GMT" }, { "version": "v2", "created": "Thu, 23 Mar 2017 14:01:20 GMT" } ]
2017-03-24T00:00:00
[ [ "Jain", "Arnav Kumar", "" ], [ "Agarwalla", "Abhinav", "" ], [ "Agrawal", "Kumar Krishna", "" ], [ "Mitra", "Pabitra", "" ] ]
TITLE: Recurrent Memory Addressing for describing videos ABSTRACT: In this paper, we introduce Key-Value Memory Networks to a multimodal setting and a novel key-addressing mechanism to deal with sequence-to-sequence models. The proposed model naturally decomposes the problem of video captioning into vision and language segments, dealing with them as key-value pairs. More specifically, we learn a semantic embedding (v) corresponding to each frame (k) in the video, thereby creating (k, v) memory slots. We propose to find the next step attention weights conditioned on the previous attention distributions for the key-value memory slots in the memory addressing schema. Exploiting this flexibility of the framework, we additionally capture spatial dependencies while mapping from the visual to semantic embedding. Experiments done on the Youtube2Text dataset demonstrate usefulness of recurrent key-addressing, while achieving competitive scores on BLEU@4, METEOR metrics against state-of-the-art models.
no_new_dataset
0.948728
1703.07807
Theja Tulabandhula
Arun Rajkumar and Koyel Mukherjee and Theja Tulabandhula
Learning to Partition using Score Based Compatibilities
Appears in the Proceedings of the 16th International Conference on Autonomous Agents and Multiagent Systems (AAMAS 2017)
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the problem of learning to partition users into groups, where one must learn the compatibilities between the users to achieve optimal groupings. We define four natural objectives that optimize for average and worst case compatibilities and propose new algorithms for adaptively learning optimal groupings. When we do not impose any structure on the compatibilities, we show that the group formation objectives considered are $NP$ hard to solve and we either give approximation guarantees or prove inapproximability results. We then introduce an elegant structure, namely that of \textit{intrinsic scores}, that makes many of these problems polynomial time solvable. We explicitly characterize the optimal groupings under this structure and show that the optimal solutions are related to \emph{homophilous} and \emph{heterophilous} partitions, well-studied in the psychology literature. For one of the four objectives, we show $NP$ hardness under the score structure and give a $\frac{1}{2}$ approximation algorithm for which no constant approximation was known thus far. Finally, under the score structure, we propose an online low sample complexity PAC algorithm for learning the optimal partition. We demonstrate the efficacy of the proposed algorithm on synthetic and real world datasets.
[ { "version": "v1", "created": "Wed, 22 Mar 2017 18:30:10 GMT" } ]
2017-03-24T00:00:00
[ [ "Rajkumar", "Arun", "" ], [ "Mukherjee", "Koyel", "" ], [ "Tulabandhula", "Theja", "" ] ]
TITLE: Learning to Partition using Score Based Compatibilities ABSTRACT: We study the problem of learning to partition users into groups, where one must learn the compatibilities between the users to achieve optimal groupings. We define four natural objectives that optimize for average and worst case compatibilities and propose new algorithms for adaptively learning optimal groupings. When we do not impose any structure on the compatibilities, we show that the group formation objectives considered are $NP$ hard to solve and we either give approximation guarantees or prove inapproximability results. We then introduce an elegant structure, namely that of \textit{intrinsic scores}, that makes many of these problems polynomial time solvable. We explicitly characterize the optimal groupings under this structure and show that the optimal solutions are related to \emph{homophilous} and \emph{heterophilous} partitions, well-studied in the psychology literature. For one of the four objectives, we show $NP$ hardness under the score structure and give a $\frac{1}{2}$ approximation algorithm for which no constant approximation was known thus far. Finally, under the score structure, we propose an online low sample complexity PAC algorithm for learning the optimal partition. We demonstrate the efficacy of the proposed algorithm on synthetic and real world datasets.
no_new_dataset
0.94428
1703.07815
Chen Chen
Yicong Tian and Chen Chen and Mubarak Shah
Cross-View Image Matching for Geo-localization in Urban Environments
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we address the problem of cross-view image geo-localization. Specifically, we aim to estimate the GPS location of a query street view image by finding the matching images in a reference database of geo-tagged bird's eye view images, or vice versa. To this end, we present a new framework for cross-view image geo-localization by taking advantage of the tremendous success of deep convolutional neural networks (CNNs) in image classification and object detection. First, we employ the Faster R-CNN to detect buildings in the query and reference images. Next, for each building in the query image, we retrieve the $k$ nearest neighbors from the reference buildings using a Siamese network trained on both positive matching image pairs and negative pairs. To find the correct NN for each query building, we develop an efficient multiple nearest neighbors matching method based on dominant sets. We evaluate the proposed framework on a new dataset that consists of pairs of street view and bird's eye view images. Experimental results show that the proposed method achieves better geo-localization accuracy than other approaches and is able to generalize to images at unseen locations.
[ { "version": "v1", "created": "Wed, 22 Mar 2017 18:51:51 GMT" } ]
2017-03-24T00:00:00
[ [ "Tian", "Yicong", "" ], [ "Chen", "Chen", "" ], [ "Shah", "Mubarak", "" ] ]
TITLE: Cross-View Image Matching for Geo-localization in Urban Environments ABSTRACT: In this paper, we address the problem of cross-view image geo-localization. Specifically, we aim to estimate the GPS location of a query street view image by finding the matching images in a reference database of geo-tagged bird's eye view images, or vice versa. To this end, we present a new framework for cross-view image geo-localization by taking advantage of the tremendous success of deep convolutional neural networks (CNNs) in image classification and object detection. First, we employ the Faster R-CNN to detect buildings in the query and reference images. Next, for each building in the query image, we retrieve the $k$ nearest neighbors from the reference buildings using a Siamese network trained on both positive matching image pairs and negative pairs. To find the correct NN for each query building, we develop an efficient multiple nearest neighbors matching method based on dominant sets. We evaluate the proposed framework on a new dataset that consists of pairs of street view and bird's eye view images. Experimental results show that the proposed method achieves better geo-localization accuracy than other approaches and is able to generalize to images at unseen locations.
new_dataset
0.961893
1703.07980
Fengfu Li
Fengfu Li, Hong Qiao, Bo Zhang, Xuanyang Xi
Discriminatively Boosted Image Clustering with Fully Convolutional Auto-Encoders
27 pages
null
null
null
cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Traditional image clustering methods take a two-step approach, feature learning and clustering, sequentially. However, recent research results demonstrated that combining the separated phases in a unified framework and training them jointly can achieve a better performance. In this paper, we first introduce fully convolutional auto-encoders for image feature learning and then propose a unified clustering framework to learn image representations and cluster centers jointly based on a fully convolutional auto-encoder and soft $k$-means scores. At initial stages of the learning procedure, the representations extracted from the auto-encoder may not be very discriminative for latter clustering. We address this issue by adopting a boosted discriminative distribution, where high score assignments are highlighted and low score ones are de-emphasized. With the gradually boosted discrimination, clustering assignment scores are discriminated and cluster purities are enlarged. Experiments on several vision benchmark datasets show that our methods can achieve a state-of-the-art performance.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 09:49:37 GMT" } ]
2017-03-24T00:00:00
[ [ "Li", "Fengfu", "" ], [ "Qiao", "Hong", "" ], [ "Zhang", "Bo", "" ], [ "Xi", "Xuanyang", "" ] ]
TITLE: Discriminatively Boosted Image Clustering with Fully Convolutional Auto-Encoders ABSTRACT: Traditional image clustering methods take a two-step approach, feature learning and clustering, sequentially. However, recent research results demonstrated that combining the separated phases in a unified framework and training them jointly can achieve a better performance. In this paper, we first introduce fully convolutional auto-encoders for image feature learning and then propose a unified clustering framework to learn image representations and cluster centers jointly based on a fully convolutional auto-encoder and soft $k$-means scores. At initial stages of the learning procedure, the representations extracted from the auto-encoder may not be very discriminative for latter clustering. We address this issue by adopting a boosted discriminative distribution, where high score assignments are highlighted and low score ones are de-emphasized. With the gradually boosted discrimination, clustering assignment scores are discriminated and cluster purities are enlarged. Experiments on several vision benchmark datasets show that our methods can achieve a state-of-the-art performance.
no_new_dataset
0.947039
1703.08002
Mirco Ravanelli
Mirco Ravanelli, Philemon Brakel, Maurizio Omologo, Yoshua Bengio
A network of deep neural networks for distant speech recognition
null
null
null
null
cs.CL cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Despite the remarkable progress recently made in distant speech recognition, state-of-the-art technology still suffers from a lack of robustness, especially when adverse acoustic conditions characterized by non-stationary noises and reverberation are met. A prominent limitation of current systems lies in the lack of matching and communication between the various technologies involved in the distant speech recognition process. The speech enhancement and speech recognition modules are, for instance, often trained independently. Moreover, the speech enhancement normally helps the speech recognizer, but the output of the latter is not commonly used, in turn, to improve the speech enhancement. To address both concerns, we propose a novel architecture based on a network of deep neural networks, where all the components are jointly trained and better cooperate with each other thanks to a full communication scheme between them. Experiments, conducted using different datasets, tasks and acoustic conditions, revealed that the proposed framework can overtake other competitive solutions, including recent joint training approaches.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 11:02:47 GMT" } ]
2017-03-24T00:00:00
[ [ "Ravanelli", "Mirco", "" ], [ "Brakel", "Philemon", "" ], [ "Omologo", "Maurizio", "" ], [ "Bengio", "Yoshua", "" ] ]
TITLE: A network of deep neural networks for distant speech recognition ABSTRACT: Despite the remarkable progress recently made in distant speech recognition, state-of-the-art technology still suffers from a lack of robustness, especially when adverse acoustic conditions characterized by non-stationary noises and reverberation are met. A prominent limitation of current systems lies in the lack of matching and communication between the various technologies involved in the distant speech recognition process. The speech enhancement and speech recognition modules are, for instance, often trained independently. Moreover, the speech enhancement normally helps the speech recognizer, but the output of the latter is not commonly used, in turn, to improve the speech enhancement. To address both concerns, we propose a novel architecture based on a network of deep neural networks, where all the components are jointly trained and better cooperate with each other thanks to a full communication scheme between them. Experiments, conducted using different datasets, tasks and acoustic conditions, revealed that the proposed framework can overtake other competitive solutions, including recent joint training approaches.
no_new_dataset
0.942718
1703.08033
Akshay Mehotra
Akshay Mehrotra, Ambedkar Dukkipati
Generative Adversarial Residual Pairwise Networks for One Shot Learning
null
null
null
null
cs.CV cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deep neural networks achieve unprecedented performance levels over many tasks and scale well with large quantities of data, but performance in the low-data regime and tasks like one shot learning still lags behind. While recent work suggests many hypotheses from better optimization to more complicated network structures, in this work we hypothesize that having a learnable and more expressive similarity objective is an essential missing component. Towards overcoming that, we propose a network design inspired by deep residual networks that allows the efficient computation of this more expressive pairwise similarity objective. Further, we argue that regularization is key in learning with small amounts of data, and propose an additional generator network based on the Generative Adversarial Networks where the discriminator is our residual pairwise network. This provides a strong regularizer by leveraging the generated data samples. The proposed model can generate plausible variations of exemplars over unseen classes and outperforms strong discriminative baselines for few shot classification tasks. Notably, our residual pairwise network design outperforms previous state-of-theart on the challenging mini-Imagenet dataset for one shot learning by getting over 55% accuracy for the 5-way classification task over unseen classes.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 12:19:09 GMT" } ]
2017-03-24T00:00:00
[ [ "Mehrotra", "Akshay", "" ], [ "Dukkipati", "Ambedkar", "" ] ]
TITLE: Generative Adversarial Residual Pairwise Networks for One Shot Learning ABSTRACT: Deep neural networks achieve unprecedented performance levels over many tasks and scale well with large quantities of data, but performance in the low-data regime and tasks like one shot learning still lags behind. While recent work suggests many hypotheses from better optimization to more complicated network structures, in this work we hypothesize that having a learnable and more expressive similarity objective is an essential missing component. Towards overcoming that, we propose a network design inspired by deep residual networks that allows the efficient computation of this more expressive pairwise similarity objective. Further, we argue that regularization is key in learning with small amounts of data, and propose an additional generator network based on the Generative Adversarial Networks where the discriminator is our residual pairwise network. This provides a strong regularizer by leveraging the generated data samples. The proposed model can generate plausible variations of exemplars over unseen classes and outperforms strong discriminative baselines for few shot classification tasks. Notably, our residual pairwise network design outperforms previous state-of-theart on the challenging mini-Imagenet dataset for one shot learning by getting over 55% accuracy for the 5-way classification task over unseen classes.
no_new_dataset
0.949902
1703.08089
Alexander Richard
Alexander Richard (1), Juergen Gall (1) ((1) University of Bonn)
A Bag-of-Words Equivalent Recurrent Neural Network for Action Recognition
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The traditional bag-of-words approach has found a wide range of applications in computer vision. The standard pipeline consists of a generation of a visual vocabulary, a quantization of the features into histograms of visual words, and a classification step for which usually a support vector machine in combination with a non-linear kernel is used. Given large amounts of data, however, the model suffers from a lack of discriminative power. This applies particularly for action recognition, where the vast amount of video features needs to be subsampled for unsupervised visual vocabulary generation. Moreover, the kernel computation can be very expensive on large datasets. In this work, we propose a recurrent neural network that is equivalent to the traditional bag-of-words approach but enables for the application of discriminative training. The model further allows to incorporate the kernel computation into the neural network directly, solving the complexity issue and allowing to represent the complete classification system within a single network. We evaluate our method on four recent action recognition benchmarks and show that the conventional model as well as sparse coding methods are outperformed.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 14:46:46 GMT" } ]
2017-03-24T00:00:00
[ [ "Richard", "Alexander", "", "University of Bonn" ], [ "Gall", "Juergen", "", "University of Bonn" ] ]
TITLE: A Bag-of-Words Equivalent Recurrent Neural Network for Action Recognition ABSTRACT: The traditional bag-of-words approach has found a wide range of applications in computer vision. The standard pipeline consists of a generation of a visual vocabulary, a quantization of the features into histograms of visual words, and a classification step for which usually a support vector machine in combination with a non-linear kernel is used. Given large amounts of data, however, the model suffers from a lack of discriminative power. This applies particularly for action recognition, where the vast amount of video features needs to be subsampled for unsupervised visual vocabulary generation. Moreover, the kernel computation can be very expensive on large datasets. In this work, we propose a recurrent neural network that is equivalent to the traditional bag-of-words approach but enables for the application of discriminative training. The model further allows to incorporate the kernel computation into the neural network directly, solving the complexity issue and allowing to represent the complete classification system within a single network. We evaluate our method on four recent action recognition benchmarks and show that the conventional model as well as sparse coding methods are outperformed.
no_new_dataset
0.94545
1703.08120
Abhijit Sharang
Abhijit Sharang, Eric Lau
Recurrent and Contextual Models for Visual Question Answering
null
null
null
null
cs.CL cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a series of recurrent and contextual neural network models for multiple choice visual question answering on the Visual7W dataset. Motivated by divergent trends in model complexities in the literature, we explore the balance between model expressiveness and simplicity by studying incrementally more complex architectures. We start with LSTM-encoding of input questions and answers; build on this with context generation by LSTM-encodings of neural image and question representations and attention over images; and evaluate the diversity and predictive power of our models and the ensemble thereof. All models are evaluated against a simple baseline inspired by the current state-of-the-art, consisting of involving simple concatenation of bag-of-words and CNN representations for the text and images, respectively. Generally, we observe marked variation in image-reasoning performance between our models not obvious from their overall performance, as well as evidence of dataset bias. Our standalone models achieve accuracies up to $64.6\%$, while the ensemble of all models achieves the best accuracy of $66.67\%$, within $0.5\%$ of the current state-of-the-art for Visual7W.
[ { "version": "v1", "created": "Thu, 23 Mar 2017 15:57:23 GMT" } ]
2017-03-24T00:00:00
[ [ "Sharang", "Abhijit", "" ], [ "Lau", "Eric", "" ] ]
TITLE: Recurrent and Contextual Models for Visual Question Answering ABSTRACT: We propose a series of recurrent and contextual neural network models for multiple choice visual question answering on the Visual7W dataset. Motivated by divergent trends in model complexities in the literature, we explore the balance between model expressiveness and simplicity by studying incrementally more complex architectures. We start with LSTM-encoding of input questions and answers; build on this with context generation by LSTM-encodings of neural image and question representations and attention over images; and evaluate the diversity and predictive power of our models and the ensemble thereof. All models are evaluated against a simple baseline inspired by the current state-of-the-art, consisting of involving simple concatenation of bag-of-words and CNN representations for the text and images, respectively. Generally, we observe marked variation in image-reasoning performance between our models not obvious from their overall performance, as well as evidence of dataset bias. Our standalone models achieve accuracies up to $64.6\%$, while the ensemble of all models achieves the best accuracy of $66.67\%$, within $0.5\%$ of the current state-of-the-art for Visual7W.
no_new_dataset
0.943243
1511.08327
Nathalie Villa-Vialaneix
Robin Genuer (ISPED, SISTM), Jean-Michel Poggi (UPD5, LM-Orsay), Christine Tuleau-Malot (JAD), Nathalie Villa-Vialaneix (MIAT INRA)
Random Forests for Big Data
null
null
null
null
stat.ML cs.LG math.ST stat.TH
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Big Data is one of the major challenges of statistical science and has numerous consequences from algorithmic and theoretical viewpoints. Big Data always involve massive data but they also often include online data and data heterogeneity. Recently some statistical methods have been adapted to process Big Data, like linear regression models, clustering methods and bootstrapping schemes. Based on decision trees combined with aggregation and bootstrap ideas, random forests were introduced by Breiman in 2001. They are a powerful nonparametric statistical method allowing to consider in a single and versatile framework regression problems, as well as two-class and multi-class classification problems. Focusing on classification problems, this paper proposes a selective review of available proposals that deal with scaling random forests to Big Data problems. These proposals rely on parallel environments or on online adaptations of random forests. We also describe how related quantities -- such as out-of-bag error and variable importance -- are addressed in these methods. Then, we formulate various remarks for random forests in the Big Data context. Finally, we experiment five variants on two massive datasets (15 and 120 millions of observations), a simulated one as well as real world data. One variant relies on subsampling while three others are related to parallel implementations of random forests and involve either various adaptations of bootstrap to Big Data or to "divide-and-conquer" approaches. The fifth variant relates on online learning of random forests. These numerical experiments lead to highlight the relative performance of the different variants, as well as some of their limitations.
[ { "version": "v1", "created": "Thu, 26 Nov 2015 09:04:47 GMT" }, { "version": "v2", "created": "Wed, 22 Mar 2017 14:51:57 GMT" } ]
2017-03-23T00:00:00
[ [ "Genuer", "Robin", "", "ISPED, SISTM" ], [ "Poggi", "Jean-Michel", "", "UPD5, LM-Orsay" ], [ "Tuleau-Malot", "Christine", "", "JAD" ], [ "Villa-Vialaneix", "Nathalie", "", "MIAT INRA" ] ]
TITLE: Random Forests for Big Data ABSTRACT: Big Data is one of the major challenges of statistical science and has numerous consequences from algorithmic and theoretical viewpoints. Big Data always involve massive data but they also often include online data and data heterogeneity. Recently some statistical methods have been adapted to process Big Data, like linear regression models, clustering methods and bootstrapping schemes. Based on decision trees combined with aggregation and bootstrap ideas, random forests were introduced by Breiman in 2001. They are a powerful nonparametric statistical method allowing to consider in a single and versatile framework regression problems, as well as two-class and multi-class classification problems. Focusing on classification problems, this paper proposes a selective review of available proposals that deal with scaling random forests to Big Data problems. These proposals rely on parallel environments or on online adaptations of random forests. We also describe how related quantities -- such as out-of-bag error and variable importance -- are addressed in these methods. Then, we formulate various remarks for random forests in the Big Data context. Finally, we experiment five variants on two massive datasets (15 and 120 millions of observations), a simulated one as well as real world data. One variant relies on subsampling while three others are related to parallel implementations of random forests and involve either various adaptations of bootstrap to Big Data or to "divide-and-conquer" approaches. The fifth variant relates on online learning of random forests. These numerical experiments lead to highlight the relative performance of the different variants, as well as some of their limitations.
no_new_dataset
0.94699
1606.07006
Xiao Yang
Xiao Yang, Craig Macdonald, Iadh Ounis
Using Word Embeddings in Twitter Election Classification
NeuIR Workshop 2016
null
null
null
cs.IR cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Word embeddings and convolutional neural networks (CNN) have attracted extensive attention in various classification tasks for Twitter, e.g. sentiment classification. However, the effect of the configuration used to train and generate the word embeddings on the classification performance has not been studied in the existing literature. In this paper, using a Twitter election classification task that aims to detect election-related tweets, we investigate the impact of the background dataset used to train the embedding models, the context window size and the dimensionality of word embeddings on the classification performance. By comparing the classification results of two word embedding models, which are trained using different background corpora (e.g. Wikipedia articles and Twitter microposts), we show that the background data type should align with the Twitter classification dataset to achieve a better performance. Moreover, by evaluating the results of word embeddings models trained using various context window sizes and dimensionalities, we found that large context window and dimension sizes are preferable to improve the performance. Our experimental results also show that using word embeddings and CNN leads to statistically significant improvements over various baselines such as random, SVM with TF-IDF and SVM with word embeddings.
[ { "version": "v1", "created": "Wed, 22 Jun 2016 16:37:55 GMT" }, { "version": "v2", "created": "Tue, 19 Jul 2016 10:22:17 GMT" }, { "version": "v3", "created": "Tue, 21 Mar 2017 18:29:49 GMT" } ]
2017-03-23T00:00:00
[ [ "Yang", "Xiao", "" ], [ "Macdonald", "Craig", "" ], [ "Ounis", "Iadh", "" ] ]
TITLE: Using Word Embeddings in Twitter Election Classification ABSTRACT: Word embeddings and convolutional neural networks (CNN) have attracted extensive attention in various classification tasks for Twitter, e.g. sentiment classification. However, the effect of the configuration used to train and generate the word embeddings on the classification performance has not been studied in the existing literature. In this paper, using a Twitter election classification task that aims to detect election-related tweets, we investigate the impact of the background dataset used to train the embedding models, the context window size and the dimensionality of word embeddings on the classification performance. By comparing the classification results of two word embedding models, which are trained using different background corpora (e.g. Wikipedia articles and Twitter microposts), we show that the background data type should align with the Twitter classification dataset to achieve a better performance. Moreover, by evaluating the results of word embeddings models trained using various context window sizes and dimensionalities, we found that large context window and dimension sizes are preferable to improve the performance. Our experimental results also show that using word embeddings and CNN leads to statistically significant improvements over various baselines such as random, SVM with TF-IDF and SVM with word embeddings.
no_new_dataset
0.954605
1609.03683
Giorgio Patrini
Giorgio Patrini, Alessandro Rozza, Aditya Menon, Richard Nock, Lizhen Qu
Making Deep Neural Networks Robust to Label Noise: a Loss Correction Approach
Oral paper at CVPR 2017
null
null
null
stat.ML cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a theoretically grounded approach to train deep neural networks, including recurrent networks, subject to class-dependent label noise. We propose two procedures for loss correction that are agnostic to both application domain and network architecture. They simply amount to at most a matrix inversion and multiplication, provided that we know the probability of each class being corrupted into another. We further show how one can estimate these probabilities, adapting a recent technique for noise estimation to the multi-class setting, and thus providing an end-to-end framework. Extensive experiments on MNIST, IMDB, CIFAR-10, CIFAR-100 and a large scale dataset of clothing images employing a diversity of architectures --- stacking dense, convolutional, pooling, dropout, batch normalization, word embedding, LSTM and residual layers --- demonstrate the noise robustness of our proposals. Incidentally, we also prove that, when ReLU is the only non-linearity, the loss curvature is immune to class-dependent label noise.
[ { "version": "v1", "created": "Tue, 13 Sep 2016 05:23:29 GMT" }, { "version": "v2", "created": "Wed, 22 Mar 2017 08:48:02 GMT" } ]
2017-03-23T00:00:00
[ [ "Patrini", "Giorgio", "" ], [ "Rozza", "Alessandro", "" ], [ "Menon", "Aditya", "" ], [ "Nock", "Richard", "" ], [ "Qu", "Lizhen", "" ] ]
TITLE: Making Deep Neural Networks Robust to Label Noise: a Loss Correction Approach ABSTRACT: We present a theoretically grounded approach to train deep neural networks, including recurrent networks, subject to class-dependent label noise. We propose two procedures for loss correction that are agnostic to both application domain and network architecture. They simply amount to at most a matrix inversion and multiplication, provided that we know the probability of each class being corrupted into another. We further show how one can estimate these probabilities, adapting a recent technique for noise estimation to the multi-class setting, and thus providing an end-to-end framework. Extensive experiments on MNIST, IMDB, CIFAR-10, CIFAR-100 and a large scale dataset of clothing images employing a diversity of architectures --- stacking dense, convolutional, pooling, dropout, batch normalization, word embedding, LSTM and residual layers --- demonstrate the noise robustness of our proposals. Incidentally, we also prove that, when ReLU is the only non-linearity, the loss curvature is immune to class-dependent label noise.
no_new_dataset
0.942082
1611.02941
Jun Sun
Jun Sun, J\'er\^ome Kunegis, Steffen Staab
Predicting User Roles in Social Networks using Transfer Learning with Feature Transformation
8 pages, 5 figures, IEEE ICDMW 2016
null
10.1109/ICDMW.2016.0026
null
cs.SI stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
How can we recognise social roles of people, given a completely unlabelled social network? We present a transfer learning approach to network role classification based on feature transformations from each network's local feature distribution to a global feature space. Experiments are carried out on real-world datasets. (See manuscript for the full abstract.)
[ { "version": "v1", "created": "Wed, 9 Nov 2016 14:15:14 GMT" } ]
2017-03-23T00:00:00
[ [ "Sun", "Jun", "" ], [ "Kunegis", "Jérôme", "" ], [ "Staab", "Steffen", "" ] ]
TITLE: Predicting User Roles in Social Networks using Transfer Learning with Feature Transformation ABSTRACT: How can we recognise social roles of people, given a completely unlabelled social network? We present a transfer learning approach to network role classification based on feature transformations from each network's local feature distribution to a global feature space. Experiments are carried out on real-world datasets. (See manuscript for the full abstract.)
no_new_dataset
0.94625