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1502.04149
Po-Sen Huang
Po-Sen Huang, Minje Kim, Mark Hasegawa-Johnson, Paris Smaragdis
Joint Optimization of Masks and Deep Recurrent Neural Networks for Monaural Source Separation
null
IEEE/ACM Transactions on Audio, Speech, and Language Processing, vol.23, no.12, pp.2136-2147, Dec. 2015
10.1109/TASLP.2015.2468583
null
cs.SD cs.AI cs.LG cs.MM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Monaural source separation is important for many real world applications. It is challenging because, with only a single channel of information available, without any constraints, an infinite number of solutions are possible. In this paper, we explore joint optimization of masking functions and deep recurrent neural networks for monaural source separation tasks, including monaural speech separation, monaural singing voice separation, and speech denoising. The joint optimization of the deep recurrent neural networks with an extra masking layer enforces a reconstruction constraint. Moreover, we explore a discriminative criterion for training neural networks to further enhance the separation performance. We evaluate the proposed system on the TSP, MIR-1K, and TIMIT datasets for speech separation, singing voice separation, and speech denoising tasks, respectively. Our approaches achieve 2.30--4.98 dB SDR gain compared to NMF models in the speech separation task, 2.30--2.48 dB GNSDR gain and 4.32--5.42 dB GSIR gain compared to existing models in the singing voice separation task, and outperform NMF and DNN baselines in the speech denoising task.
[ { "version": "v1", "created": "Fri, 13 Feb 2015 23:22:16 GMT" }, { "version": "v2", "created": "Tue, 2 Jun 2015 04:22:20 GMT" }, { "version": "v3", "created": "Thu, 13 Aug 2015 04:20:33 GMT" }, { "version": "v4", "created": "Thu, 1 Oct 2015 02:58:01 GMT" } ]
2015-10-02T00:00:00
[ [ "Huang", "Po-Sen", "" ], [ "Kim", "Minje", "" ], [ "Hasegawa-Johnson", "Mark", "" ], [ "Smaragdis", "Paris", "" ] ]
TITLE: Joint Optimization of Masks and Deep Recurrent Neural Networks for Monaural Source Separation ABSTRACT: Monaural source separation is important for many real world applications. It is challenging because, with only a single channel of information available, without any constraints, an infinite number of solutions are possible. In this paper, we explore joint optimization of masking functions and deep recurrent neural networks for monaural source separation tasks, including monaural speech separation, monaural singing voice separation, and speech denoising. The joint optimization of the deep recurrent neural networks with an extra masking layer enforces a reconstruction constraint. Moreover, we explore a discriminative criterion for training neural networks to further enhance the separation performance. We evaluate the proposed system on the TSP, MIR-1K, and TIMIT datasets for speech separation, singing voice separation, and speech denoising tasks, respectively. Our approaches achieve 2.30--4.98 dB SDR gain compared to NMF models in the speech separation task, 2.30--2.48 dB GNSDR gain and 4.32--5.42 dB GSIR gain compared to existing models in the singing voice separation task, and outperform NMF and DNN baselines in the speech denoising task.
no_new_dataset
0.950088
1502.08029
Li Yao
Li Yao, Atousa Torabi, Kyunghyun Cho, Nicolas Ballas, Christopher Pal, Hugo Larochelle, Aaron Courville
Describing Videos by Exploiting Temporal Structure
Accepted to ICCV15. This version comes with code release and supplementary material
null
null
null
stat.ML cs.AI cs.CL cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent progress in using recurrent neural networks (RNNs) for image description has motivated the exploration of their application for video description. However, while images are static, working with videos requires modeling their dynamic temporal structure and then properly integrating that information into a natural language description. In this context, we propose an approach that successfully takes into account both the local and global temporal structure of videos to produce descriptions. First, our approach incorporates a spatial temporal 3-D convolutional neural network (3-D CNN) representation of the short temporal dynamics. The 3-D CNN representation is trained on video action recognition tasks, so as to produce a representation that is tuned to human motion and behavior. Second we propose a temporal attention mechanism that allows to go beyond local temporal modeling and learns to automatically select the most relevant temporal segments given the text-generating RNN. Our approach exceeds the current state-of-art for both BLEU and METEOR metrics on the Youtube2Text dataset. We also present results on a new, larger and more challenging dataset of paired video and natural language descriptions.
[ { "version": "v1", "created": "Fri, 27 Feb 2015 19:30:40 GMT" }, { "version": "v2", "created": "Wed, 4 Mar 2015 17:24:47 GMT" }, { "version": "v3", "created": "Tue, 10 Mar 2015 15:27:08 GMT" }, { "version": "v4", "created": "Sat, 25 Apr 2015 20:32:27 GMT" }, { "version": "v5", "created": "Thu, 1 Oct 2015 00:12:46 GMT" } ]
2015-10-02T00:00:00
[ [ "Yao", "Li", "" ], [ "Torabi", "Atousa", "" ], [ "Cho", "Kyunghyun", "" ], [ "Ballas", "Nicolas", "" ], [ "Pal", "Christopher", "" ], [ "Larochelle", "Hugo", "" ], [ "Courville", "Aaron", "" ] ]
TITLE: Describing Videos by Exploiting Temporal Structure ABSTRACT: Recent progress in using recurrent neural networks (RNNs) for image description has motivated the exploration of their application for video description. However, while images are static, working with videos requires modeling their dynamic temporal structure and then properly integrating that information into a natural language description. In this context, we propose an approach that successfully takes into account both the local and global temporal structure of videos to produce descriptions. First, our approach incorporates a spatial temporal 3-D convolutional neural network (3-D CNN) representation of the short temporal dynamics. The 3-D CNN representation is trained on video action recognition tasks, so as to produce a representation that is tuned to human motion and behavior. Second we propose a temporal attention mechanism that allows to go beyond local temporal modeling and learns to automatically select the most relevant temporal segments given the text-generating RNN. Our approach exceeds the current state-of-art for both BLEU and METEOR metrics on the Youtube2Text dataset. We also present results on a new, larger and more challenging dataset of paired video and natural language descriptions.
new_dataset
0.96856
1504.04211
Zied Ben Bouallegue
Zied Ben Bouallegue, Pierre Pinson, Petra Friederichs
Quantile forecast discrimination ability and value
null
null
10.1002/qj.2624
null
physics.ao-ph physics.data-an stat.AP
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
While probabilistic forecast verification for categorical forecasts is well established, some of the existing concepts and methods have not found their equivalent for the case of continuous variables. New tools dedicated to the assessment of forecast discrimination ability and forecast value are introduced here, based on quantile forecasts being the base product for the continuous case (hence in a nonparametric framework). The relative user characteristic (RUC) curve and the quantile value plot allow analysing the performance of a forecast for a specific user in a decision-making framework. The RUC curve is designed as a user-based discrimination tool and the quantile value plot translates forecast discrimination ability in terms of economic value. The relationship between the overall value of a quantile forecast and the respective quantile skill score is also discussed. The application of these new verification approaches and tools is illustrated based on synthetic datasets, as well as for the case of global radiation forecasts from the high resolution ensemble COSMO-DE-EPS of the German Weather Service.
[ { "version": "v1", "created": "Thu, 16 Apr 2015 12:45:35 GMT" } ]
2015-10-02T00:00:00
[ [ "Bouallegue", "Zied Ben", "" ], [ "Pinson", "Pierre", "" ], [ "Friederichs", "Petra", "" ] ]
TITLE: Quantile forecast discrimination ability and value ABSTRACT: While probabilistic forecast verification for categorical forecasts is well established, some of the existing concepts and methods have not found their equivalent for the case of continuous variables. New tools dedicated to the assessment of forecast discrimination ability and forecast value are introduced here, based on quantile forecasts being the base product for the continuous case (hence in a nonparametric framework). The relative user characteristic (RUC) curve and the quantile value plot allow analysing the performance of a forecast for a specific user in a decision-making framework. The RUC curve is designed as a user-based discrimination tool and the quantile value plot translates forecast discrimination ability in terms of economic value. The relationship between the overall value of a quantile forecast and the respective quantile skill score is also discussed. The application of these new verification approaches and tools is illustrated based on synthetic datasets, as well as for the case of global radiation forecasts from the high resolution ensemble COSMO-DE-EPS of the German Weather Service.
no_new_dataset
0.947332
1505.01121
Mateusz Malinowski
Mateusz Malinowski and Marcus Rohrbach and Mario Fritz
Ask Your Neurons: A Neural-based Approach to Answering Questions about Images
ICCV'15 (Oral)
null
null
null
cs.CV cs.AI cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We address a question answering task on real-world images that is set up as a Visual Turing Test. By combining latest advances in image representation and natural language processing, we propose Neural-Image-QA, an end-to-end formulation to this problem for which all parts are trained jointly. In contrast to previous efforts, we are facing a multi-modal problem where the language output (answer) is conditioned on visual and natural language input (image and question). Our approach Neural-Image-QA doubles the performance of the previous best approach on this problem. We provide additional insights into the problem by analyzing how much information is contained only in the language part for which we provide a new human baseline. To study human consensus, which is related to the ambiguities inherent in this challenging task, we propose two novel metrics and collect additional answers which extends the original DAQUAR dataset to DAQUAR-Consensus.
[ { "version": "v1", "created": "Tue, 5 May 2015 18:39:29 GMT" }, { "version": "v2", "created": "Wed, 6 May 2015 08:10:01 GMT" }, { "version": "v3", "created": "Thu, 1 Oct 2015 12:13:20 GMT" } ]
2015-10-02T00:00:00
[ [ "Malinowski", "Mateusz", "" ], [ "Rohrbach", "Marcus", "" ], [ "Fritz", "Mario", "" ] ]
TITLE: Ask Your Neurons: A Neural-based Approach to Answering Questions about Images ABSTRACT: We address a question answering task on real-world images that is set up as a Visual Turing Test. By combining latest advances in image representation and natural language processing, we propose Neural-Image-QA, an end-to-end formulation to this problem for which all parts are trained jointly. In contrast to previous efforts, we are facing a multi-modal problem where the language output (answer) is conditioned on visual and natural language input (image and question). Our approach Neural-Image-QA doubles the performance of the previous best approach on this problem. We provide additional insights into the problem by analyzing how much information is contained only in the language part for which we provide a new human baseline. To study human consensus, which is related to the ambiguities inherent in this challenging task, we propose two novel metrics and collect additional answers which extends the original DAQUAR dataset to DAQUAR-Consensus.
no_new_dataset
0.948251
1509.08147
Abhishek Kar
Abhishek Kar, Shubham Tulsiani, Jo\~ao Carreira, Jitendra Malik
Amodal Completion and Size Constancy in Natural Scenes
Accepted to ICCV 2015
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the problem of enriching current object detection systems with veridical object sizes and relative depth estimates from a single image. There are several technical challenges to this, such as occlusions, lack of calibration data and the scale ambiguity between object size and distance. These have not been addressed in full generality in previous work. Here we propose to tackle these issues by building upon advances in object recognition and using recently created large-scale datasets. We first introduce the task of amodal bounding box completion, which aims to infer the the full extent of the object instances in the image. We then propose a probabilistic framework for learning category-specific object size distributions from available annotations and leverage these in conjunction with amodal completion to infer veridical sizes in novel images. Finally, we introduce a focal length prediction approach that exploits scene recognition to overcome inherent scaling ambiguities and we demonstrate qualitative results on challenging real-world scenes.
[ { "version": "v1", "created": "Sun, 27 Sep 2015 21:39:42 GMT" }, { "version": "v2", "created": "Thu, 1 Oct 2015 04:34:06 GMT" } ]
2015-10-02T00:00:00
[ [ "Kar", "Abhishek", "" ], [ "Tulsiani", "Shubham", "" ], [ "Carreira", "João", "" ], [ "Malik", "Jitendra", "" ] ]
TITLE: Amodal Completion and Size Constancy in Natural Scenes ABSTRACT: We consider the problem of enriching current object detection systems with veridical object sizes and relative depth estimates from a single image. There are several technical challenges to this, such as occlusions, lack of calibration data and the scale ambiguity between object size and distance. These have not been addressed in full generality in previous work. Here we propose to tackle these issues by building upon advances in object recognition and using recently created large-scale datasets. We first introduce the task of amodal bounding box completion, which aims to infer the the full extent of the object instances in the image. We then propose a probabilistic framework for learning category-specific object size distributions from available annotations and leverage these in conjunction with amodal completion to infer veridical sizes in novel images. Finally, we introduce a focal length prediction approach that exploits scene recognition to overcome inherent scaling ambiguities and we demonstrate qualitative results on challenging real-world scenes.
new_dataset
0.964254
1411.6387
Chunhua Shen
Fayao Liu, Chunhua Shen, Guosheng Lin
Deep Convolutional Neural Fields for Depth Estimation from a Single Image
fixed some typos. in CVPR15 proceedings
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the problem of depth estimation from a single monocular image in this work. It is a challenging task as no reliable depth cues are available, e.g., stereo correspondences, motions, etc. Previous efforts have been focusing on exploiting geometric priors or additional sources of information, with all using hand-crafted features. Recently, there is mounting evidence that features from deep convolutional neural networks (CNN) are setting new records for various vision applications. On the other hand, considering the continuous characteristic of the depth values, depth estimations can be naturally formulated into a continuous conditional random field (CRF) learning problem. Therefore, we in this paper present a deep convolutional neural field model for estimating depths from a single image, aiming to jointly explore the capacity of deep CNN and continuous CRF. Specifically, we propose a deep structured learning scheme which learns the unary and pairwise potentials of continuous CRF in a unified deep CNN framework. The proposed method can be used for depth estimations of general scenes with no geometric priors nor any extra information injected. In our case, the integral of the partition function can be analytically calculated, thus we can exactly solve the log-likelihood optimization. Moreover, solving the MAP problem for predicting depths of a new image is highly efficient as closed-form solutions exist. We experimentally demonstrate that the proposed method outperforms state-of-the-art depth estimation methods on both indoor and outdoor scene datasets.
[ { "version": "v1", "created": "Mon, 24 Nov 2014 09:13:00 GMT" }, { "version": "v2", "created": "Thu, 18 Dec 2014 04:11:14 GMT" } ]
2015-10-01T00:00:00
[ [ "Liu", "Fayao", "" ], [ "Shen", "Chunhua", "" ], [ "Lin", "Guosheng", "" ] ]
TITLE: Deep Convolutional Neural Fields for Depth Estimation from a Single Image ABSTRACT: We consider the problem of depth estimation from a single monocular image in this work. It is a challenging task as no reliable depth cues are available, e.g., stereo correspondences, motions, etc. Previous efforts have been focusing on exploiting geometric priors or additional sources of information, with all using hand-crafted features. Recently, there is mounting evidence that features from deep convolutional neural networks (CNN) are setting new records for various vision applications. On the other hand, considering the continuous characteristic of the depth values, depth estimations can be naturally formulated into a continuous conditional random field (CRF) learning problem. Therefore, we in this paper present a deep convolutional neural field model for estimating depths from a single image, aiming to jointly explore the capacity of deep CNN and continuous CRF. Specifically, we propose a deep structured learning scheme which learns the unary and pairwise potentials of continuous CRF in a unified deep CNN framework. The proposed method can be used for depth estimations of general scenes with no geometric priors nor any extra information injected. In our case, the integral of the partition function can be analytically calculated, thus we can exactly solve the log-likelihood optimization. Moreover, solving the MAP problem for predicting depths of a new image is highly efficient as closed-form solutions exist. We experimentally demonstrate that the proposed method outperforms state-of-the-art depth estimation methods on both indoor and outdoor scene datasets.
no_new_dataset
0.945751
1507.08799
Christian Mandery
Christian Mandery and J\'ulia Borr\`as and Mirjam J\"ochner and Tamim Asfour
Analyzing Whole-Body Pose Transitions in Multi-Contact Motions
8 pages, IEEE-RAS International Conference on Humanoid Robots (Humanoids) 2015
null
null
null
cs.RO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
When executing whole-body motions, humans are able to use a large variety of support poses which not only utilize the feet, but also hands, knees and elbows to enhance stability. While there are many works analyzing the transitions involved in walking, very few works analyze human motion where more complex supports occur. In this work, we analyze complex support pose transitions in human motion involving locomotion and manipulation tasks (loco-manipulation). We have applied a method for the detection of human support contacts from motion capture data to a large-scale dataset of loco-manipulation motions involving multi-contact supports, providing a semantic representation of them. Our results provide a statistical analysis of the used support poses, their transitions and the time spent in each of them. In addition, our data partially validates our taxonomy of whole-body support poses presented in our previous work. We believe that this work extends our understanding of human motion for humanoids, with a long-term objective of developing methods for autonomous multi-contact motion planning.
[ { "version": "v1", "created": "Fri, 31 Jul 2015 08:51:51 GMT" }, { "version": "v2", "created": "Wed, 30 Sep 2015 12:04:07 GMT" } ]
2015-10-01T00:00:00
[ [ "Mandery", "Christian", "" ], [ "Borràs", "Júlia", "" ], [ "Jöchner", "Mirjam", "" ], [ "Asfour", "Tamim", "" ] ]
TITLE: Analyzing Whole-Body Pose Transitions in Multi-Contact Motions ABSTRACT: When executing whole-body motions, humans are able to use a large variety of support poses which not only utilize the feet, but also hands, knees and elbows to enhance stability. While there are many works analyzing the transitions involved in walking, very few works analyze human motion where more complex supports occur. In this work, we analyze complex support pose transitions in human motion involving locomotion and manipulation tasks (loco-manipulation). We have applied a method for the detection of human support contacts from motion capture data to a large-scale dataset of loco-manipulation motions involving multi-contact supports, providing a semantic representation of them. Our results provide a statistical analysis of the used support poses, their transitions and the time spent in each of them. In addition, our data partially validates our taxonomy of whole-body support poses presented in our previous work. We believe that this work extends our understanding of human motion for humanoids, with a long-term objective of developing methods for autonomous multi-contact motion planning.
no_new_dataset
0.503082
1509.09030
Sourangshu Bhattacharya
Ayan Das and Sourangshu Bhattacharya
Distributed Weighted Parameter Averaging for SVM Training on Big Data
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Two popular approaches for distributed training of SVMs on big data are parameter averaging and ADMM. Parameter averaging is efficient but suffers from loss of accuracy with increase in number of partitions, while ADMM in the feature space is accurate but suffers from slow convergence. In this paper, we report a hybrid approach called weighted parameter averaging (WPA), which optimizes the regularized hinge loss with respect to weights on parameters. The problem is shown to be same as solving SVM in a projected space. We also demonstrate an $O(\frac{1}{N})$ stability bound on final hypothesis given by WPA, using novel proof techniques. Experimental results on a variety of toy and real world datasets show that our approach is significantly more accurate than parameter averaging for high number of partitions. It is also seen the proposed method enjoys much faster convergence compared to ADMM in features space.
[ { "version": "v1", "created": "Wed, 30 Sep 2015 06:59:31 GMT" } ]
2015-10-01T00:00:00
[ [ "Das", "Ayan", "" ], [ "Bhattacharya", "Sourangshu", "" ] ]
TITLE: Distributed Weighted Parameter Averaging for SVM Training on Big Data ABSTRACT: Two popular approaches for distributed training of SVMs on big data are parameter averaging and ADMM. Parameter averaging is efficient but suffers from loss of accuracy with increase in number of partitions, while ADMM in the feature space is accurate but suffers from slow convergence. In this paper, we report a hybrid approach called weighted parameter averaging (WPA), which optimizes the regularized hinge loss with respect to weights on parameters. The problem is shown to be same as solving SVM in a projected space. We also demonstrate an $O(\frac{1}{N})$ stability bound on final hypothesis given by WPA, using novel proof techniques. Experimental results on a variety of toy and real world datasets show that our approach is significantly more accurate than parameter averaging for high number of partitions. It is also seen the proposed method enjoys much faster convergence compared to ADMM in features space.
no_new_dataset
0.95096
1509.09055
Marc Barthelemy
Julien Perret, Maurizio Gribaudi, Marc Barthelemy
Roads and cities of $18^{th}$ century France
12 pages, 4 figures
Scientific Data 2, Article number: 150048 (2015)
null
null
physics.soc-ph cond-mat.dis-nn cs.CY
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The evolution of infrastructure networks such as roads and streets are of utmost importance to understand the evolution of urban systems. However, datasets describing these spatial objects are rare and sparse. The database presented here represents the road network at the french national level described in the historical map of Cassini in the $18^{th}$ century. The digitization of this historical map is based on a collaborative methodology that we describe in detail. This dataset can be used for a variety of interdisciplinary studies, covering multiple spatial resolutions and ranging from history, geography, urban economics to network science.
[ { "version": "v1", "created": "Wed, 30 Sep 2015 08:07:36 GMT" } ]
2015-10-01T00:00:00
[ [ "Perret", "Julien", "" ], [ "Gribaudi", "Maurizio", "" ], [ "Barthelemy", "Marc", "" ] ]
TITLE: Roads and cities of $18^{th}$ century France ABSTRACT: The evolution of infrastructure networks such as roads and streets are of utmost importance to understand the evolution of urban systems. However, datasets describing these spatial objects are rare and sparse. The database presented here represents the road network at the french national level described in the historical map of Cassini in the $18^{th}$ century. The digitization of this historical map is based on a collaborative methodology that we describe in detail. This dataset can be used for a variety of interdisciplinary studies, covering multiple spatial resolutions and ranging from history, geography, urban economics to network science.
new_dataset
0.917377
1509.09114
Karteek Alahari
Yang Hua, Karteek Alahari, Cordelia Schmid
Online Object Tracking with Proposal Selection
ICCV 2015
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Tracking-by-detection approaches are some of the most successful object trackers in recent years. Their success is largely determined by the detector model they learn initially and then update over time. However, under challenging conditions where an object can undergo transformations, e.g., severe rotation, these methods are found to be lacking. In this paper, we address this problem by formulating it as a proposal selection task and making two contributions. The first one is introducing novel proposals estimated from the geometric transformations undergone by the object, and building a rich candidate set for predicting the object location. The second one is devising a novel selection strategy using multiple cues, i.e., detection score and edgeness score computed from state-of-the-art object edges and motion boundaries. We extensively evaluate our approach on the visual object tracking 2014 challenge and online tracking benchmark datasets, and show the best performance.
[ { "version": "v1", "created": "Wed, 30 Sep 2015 10:38:27 GMT" } ]
2015-10-01T00:00:00
[ [ "Hua", "Yang", "" ], [ "Alahari", "Karteek", "" ], [ "Schmid", "Cordelia", "" ] ]
TITLE: Online Object Tracking with Proposal Selection ABSTRACT: Tracking-by-detection approaches are some of the most successful object trackers in recent years. Their success is largely determined by the detector model they learn initially and then update over time. However, under challenging conditions where an object can undergo transformations, e.g., severe rotation, these methods are found to be lacking. In this paper, we address this problem by formulating it as a proposal selection task and making two contributions. The first one is introducing novel proposals estimated from the geometric transformations undergone by the object, and building a rich candidate set for predicting the object location. The second one is devising a novel selection strategy using multiple cues, i.e., detection score and edgeness score computed from state-of-the-art object edges and motion boundaries. We extensively evaluate our approach on the visual object tracking 2014 challenge and online tracking benchmark datasets, and show the best performance.
no_new_dataset
0.949201
1509.09130
Claire Vernade
Claire Vernade (LTCI), Olivier Capp\'e (LTCI)
Learning From Missing Data Using Selection Bias in Movie Recommendation
null
null
null
null
stat.ML cs.IR cs.LG cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recommending items to users is a challenging task due to the large amount of missing information. In many cases, the data solely consist of ratings or tags voluntarily contributed by each user on a very limited subset of the available items, so that most of the data of potential interest is actually missing. Current approaches to recommendation usually assume that the unobserved data is missing at random. In this contribution, we provide statistical evidence that existing movie recommendation datasets reveal a significant positive association between the rating of items and the propensity to select these items. We propose a computationally efficient variational approach that makes it possible to exploit this selection bias so as to improve the estimation of ratings from small populations of users. Results obtained with this approach applied to neighborhood-based collaborative filtering illustrate its potential for improving the reliability of the recommendation.
[ { "version": "v1", "created": "Wed, 30 Sep 2015 11:40:21 GMT" } ]
2015-10-01T00:00:00
[ [ "Vernade", "Claire", "", "LTCI" ], [ "Cappé", "Olivier", "", "LTCI" ] ]
TITLE: Learning From Missing Data Using Selection Bias in Movie Recommendation ABSTRACT: Recommending items to users is a challenging task due to the large amount of missing information. In many cases, the data solely consist of ratings or tags voluntarily contributed by each user on a very limited subset of the available items, so that most of the data of potential interest is actually missing. Current approaches to recommendation usually assume that the unobserved data is missing at random. In this contribution, we provide statistical evidence that existing movie recommendation datasets reveal a significant positive association between the rating of items and the propensity to select these items. We propose a computationally efficient variational approach that makes it possible to exploit this selection bias so as to improve the estimation of ratings from small populations of users. Results obtained with this approach applied to neighborhood-based collaborative filtering illustrate its potential for improving the reliability of the recommendation.
no_new_dataset
0.951369
1509.09254
Harry Crane
Harry Crane and Walter Dempsey
Community detection for interaction networks
29 pages, 3 figures
null
null
null
cs.SI physics.soc-ph stat.ME
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In many applications, it is common practice to obtain a network from interaction counts by thresholding each pairwise count at a prescribed value. Our analysis calls attention to the dependence of certain methods, notably Newman--Girvan modularity, on the choice of threshold. Essentially, the threshold either separates the network into clusters automatically, making the algorithm's job trivial, or erases all structure in the data, rendering clustering impossible. By fitting the original interaction counts as given, we show that minor modifications to classical statistical methods outperform the prevailing approaches for community detection from interaction datasets. We also introduce a new hidden Markov model for inferring community structures that vary over time. We demonstrate each of these features on three real datasets: the karate club dataset, voting data from the U.S.\ Senate (2001--2003), and temporal voting data for the U.S. Supreme Court (1990--2004).
[ { "version": "v1", "created": "Wed, 30 Sep 2015 16:56:05 GMT" } ]
2015-10-01T00:00:00
[ [ "Crane", "Harry", "" ], [ "Dempsey", "Walter", "" ] ]
TITLE: Community detection for interaction networks ABSTRACT: In many applications, it is common practice to obtain a network from interaction counts by thresholding each pairwise count at a prescribed value. Our analysis calls attention to the dependence of certain methods, notably Newman--Girvan modularity, on the choice of threshold. Essentially, the threshold either separates the network into clusters automatically, making the algorithm's job trivial, or erases all structure in the data, rendering clustering impossible. By fitting the original interaction counts as given, we show that minor modifications to classical statistical methods outperform the prevailing approaches for community detection from interaction datasets. We also introduce a new hidden Markov model for inferring community structures that vary over time. We demonstrate each of these features on three real datasets: the karate club dataset, voting data from the U.S.\ Senate (2001--2003), and temporal voting data for the U.S. Supreme Court (1990--2004).
no_new_dataset
0.949342
1509.09313
Grey Ballard
Ramakrishnan Kannan and Grey Ballard and Haesun Park
A High-Performance Parallel Algorithm for Nonnegative Matrix Factorization
null
null
null
null
cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Non-negative matrix factorization (NMF) is the problem of determining two non-negative low rank factors $W$ and $H$, for the given input matrix $A$, such that $A \approx W H$. NMF is a useful tool for many applications in different domains such as topic modeling in text mining, background separation in video analysis, and community detection in social networks. Despite its popularity in the data mining community, there is a lack of efficient parallel software to solve the problem for big datasets. Existing distributed-memory algorithms are limited in terms of performance and applicability, as they are implemented using Hadoop and are designed only for sparse matrices. We propose a distributed-memory parallel algorithm that computes the factorization by iteratively solving alternating non-negative least squares (NLS) subproblems for $W$ and $H$. To our knowledge, our algorithm is the first high-performance parallel algorithm for NMF. It maintains the data and factor matrices in memory (distributed across processors), uses MPI for interprocessor communication, and, in the dense case, provably minimizes communication costs (under mild assumptions). As opposed to previous implementations, our algorithm is also flexible: (1) it performs well for dense and sparse matrices, and (2) it allows the user to choose from among multiple algorithms for solving local NLS subproblems within the alternating iterations. We demonstrate the scalability of our algorithm and compare it with baseline implementations, showing significant performance improvements.
[ { "version": "v1", "created": "Wed, 30 Sep 2015 19:47:39 GMT" } ]
2015-10-01T00:00:00
[ [ "Kannan", "Ramakrishnan", "" ], [ "Ballard", "Grey", "" ], [ "Park", "Haesun", "" ] ]
TITLE: A High-Performance Parallel Algorithm for Nonnegative Matrix Factorization ABSTRACT: Non-negative matrix factorization (NMF) is the problem of determining two non-negative low rank factors $W$ and $H$, for the given input matrix $A$, such that $A \approx W H$. NMF is a useful tool for many applications in different domains such as topic modeling in text mining, background separation in video analysis, and community detection in social networks. Despite its popularity in the data mining community, there is a lack of efficient parallel software to solve the problem for big datasets. Existing distributed-memory algorithms are limited in terms of performance and applicability, as they are implemented using Hadoop and are designed only for sparse matrices. We propose a distributed-memory parallel algorithm that computes the factorization by iteratively solving alternating non-negative least squares (NLS) subproblems for $W$ and $H$. To our knowledge, our algorithm is the first high-performance parallel algorithm for NMF. It maintains the data and factor matrices in memory (distributed across processors), uses MPI for interprocessor communication, and, in the dense case, provably minimizes communication costs (under mild assumptions). As opposed to previous implementations, our algorithm is also flexible: (1) it performs well for dense and sparse matrices, and (2) it allows the user to choose from among multiple algorithms for solving local NLS subproblems within the alternating iterations. We demonstrate the scalability of our algorithm and compare it with baseline implementations, showing significant performance improvements.
no_new_dataset
0.939913
1412.1470
Mostafa Haghir Chehreghani
Mostafa Haghir Chehreghani and Maurice Bruynooghe
Mining Rooted Ordered Trees under Subtree Homeomorphism
This paper is accepted in the Data Mining and Knowledge Discovery journal (http://www.springer.com/computer/database+management+%26+information+retrieval/journal/10618)
null
null
null
cs.DB cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Mining frequent tree patterns has many applications in different areas such as XML data, bioinformatics and World Wide Web. The crucial step in frequent pattern mining is frequency counting, which involves a matching operator to find occurrences (instances) of a tree pattern in a given collection of trees. A widely used matching operator for tree-structured data is subtree homeomorphism, where an edge in the tree pattern is mapped onto an ancestor-descendant relationship in the given tree. Tree patterns that are frequent under subtree homeomorphism are usually called embedded patterns. In this paper, we present an efficient algorithm for subtree homeomorphism with application to frequent pattern mining. We propose a compact data-structure, called occ, which stores only information about the rightmost paths of occurrences and hence can encode and represent several occurrences of a tree pattern. We then define efficient join operations on the occ data-structure, which help us count occurrences of tree patterns according to occurrences of their proper subtrees. Based on the proposed subtree homeomorphism method, we develop an effective pattern mining algorithm, called TPMiner. We evaluate the efficiency of TPMiner on several real-world and synthetic datasets. Our extensive experiments confirm that TPMiner always outperforms well-known existing algorithms, and in several cases the improvement with respect to existing algorithms is significant.
[ { "version": "v1", "created": "Wed, 3 Dec 2014 15:57:00 GMT" }, { "version": "v2", "created": "Fri, 24 Apr 2015 17:43:23 GMT" }, { "version": "v3", "created": "Mon, 28 Sep 2015 20:36:21 GMT" } ]
2015-09-30T00:00:00
[ [ "Chehreghani", "Mostafa Haghir", "" ], [ "Bruynooghe", "Maurice", "" ] ]
TITLE: Mining Rooted Ordered Trees under Subtree Homeomorphism ABSTRACT: Mining frequent tree patterns has many applications in different areas such as XML data, bioinformatics and World Wide Web. The crucial step in frequent pattern mining is frequency counting, which involves a matching operator to find occurrences (instances) of a tree pattern in a given collection of trees. A widely used matching operator for tree-structured data is subtree homeomorphism, where an edge in the tree pattern is mapped onto an ancestor-descendant relationship in the given tree. Tree patterns that are frequent under subtree homeomorphism are usually called embedded patterns. In this paper, we present an efficient algorithm for subtree homeomorphism with application to frequent pattern mining. We propose a compact data-structure, called occ, which stores only information about the rightmost paths of occurrences and hence can encode and represent several occurrences of a tree pattern. We then define efficient join operations on the occ data-structure, which help us count occurrences of tree patterns according to occurrences of their proper subtrees. Based on the proposed subtree homeomorphism method, we develop an effective pattern mining algorithm, called TPMiner. We evaluate the efficiency of TPMiner on several real-world and synthetic datasets. Our extensive experiments confirm that TPMiner always outperforms well-known existing algorithms, and in several cases the improvement with respect to existing algorithms is significant.
no_new_dataset
0.951863
1504.05351
Anirban Sen
Siddharth Bora, Harvineet Singh, Anirban Sen, Amitabha Bagchi, Parag Singla
On the Role of Conductance, Geography and Topology in Predicting Hashtag Virality
null
Soc. Netw. Anal. Min. 5(1):57, December 2015
10.1007/s13278-015-0300-2
null
cs.SI physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We focus on three aspects of the early spread of a hashtag in order to predict whether it will go viral: the network properties of the subset of users tweeting the hashtag, its geographical properties, and, most importantly, its conductance-related properties. One of our significant contributions is to discover the critical role played by the conductance based features for the successful prediction of virality. More specifically, we show that the first derivative of the conductance gives an early indication of whether the hashtag is going to go viral or not. We present a detailed experimental evaluation of the effect of our various categories of features on the virality prediction task. When compared to the baselines and the state of the art techniques proposed in the literature our feature set is able to achieve significantly better accuracy on a large dataset of 7.7 million users and all their tweets over a period of month, as well as on existing datasets.
[ { "version": "v1", "created": "Tue, 21 Apr 2015 09:30:34 GMT" } ]
2015-09-30T00:00:00
[ [ "Bora", "Siddharth", "" ], [ "Singh", "Harvineet", "" ], [ "Sen", "Anirban", "" ], [ "Bagchi", "Amitabha", "" ], [ "Singla", "Parag", "" ] ]
TITLE: On the Role of Conductance, Geography and Topology in Predicting Hashtag Virality ABSTRACT: We focus on three aspects of the early spread of a hashtag in order to predict whether it will go viral: the network properties of the subset of users tweeting the hashtag, its geographical properties, and, most importantly, its conductance-related properties. One of our significant contributions is to discover the critical role played by the conductance based features for the successful prediction of virality. More specifically, we show that the first derivative of the conductance gives an early indication of whether the hashtag is going to go viral or not. We present a detailed experimental evaluation of the effect of our various categories of features on the virality prediction task. When compared to the baselines and the state of the art techniques proposed in the literature our feature set is able to achieve significantly better accuracy on a large dataset of 7.7 million users and all their tweets over a period of month, as well as on existing datasets.
no_new_dataset
0.939637
1509.05257
Ernesto Diaz-Aviles
Hoang Thanh Lam and Ernesto Diaz-Aviles and Alessandra Pascale and Yiannis Gkoufas and Bei Chen
(Blue) Taxi Destination and Trip Time Prediction from Partial Trajectories
ECML/PKDD Discovery Challenge 2015
null
null
null
stat.ML cs.AI cs.CY cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Real-time estimation of destination and travel time for taxis is of great importance for existing electronic dispatch systems. We present an approach based on trip matching and ensemble learning, in which we leverage the patterns observed in a dataset of roughly 1.7 million taxi journeys to predict the corresponding final destination and travel time for ongoing taxi trips, as a solution for the ECML/PKDD Discovery Challenge 2015 competition. The results of our empirical evaluation show that our approach is effective and very robust, which led our team -- BlueTaxi -- to the 3rd and 7th position of the final rankings for the trip time and destination prediction tasks, respectively. Given the fact that the final rankings were computed using a very small test set (with only 320 trips) we believe that our approach is one of the most robust solutions for the challenge based on the consistency of our good results across the test sets.
[ { "version": "v1", "created": "Thu, 17 Sep 2015 13:51:55 GMT" } ]
2015-09-30T00:00:00
[ [ "Lam", "Hoang Thanh", "" ], [ "Diaz-Aviles", "Ernesto", "" ], [ "Pascale", "Alessandra", "" ], [ "Gkoufas", "Yiannis", "" ], [ "Chen", "Bei", "" ] ]
TITLE: (Blue) Taxi Destination and Trip Time Prediction from Partial Trajectories ABSTRACT: Real-time estimation of destination and travel time for taxis is of great importance for existing electronic dispatch systems. We present an approach based on trip matching and ensemble learning, in which we leverage the patterns observed in a dataset of roughly 1.7 million taxi journeys to predict the corresponding final destination and travel time for ongoing taxi trips, as a solution for the ECML/PKDD Discovery Challenge 2015 competition. The results of our empirical evaluation show that our approach is effective and very robust, which led our team -- BlueTaxi -- to the 3rd and 7th position of the final rankings for the trip time and destination prediction tasks, respectively. Given the fact that the final rankings were computed using a very small test set (with only 320 trips) we believe that our approach is one of the most robust solutions for the challenge based on the consistency of our good results across the test sets.
no_new_dataset
0.934215
1509.08863
Nicolas Tremblay
Nicolas Tremblay, Gilles Puy, Pierre Borgnat, Remi Gribonval, Pierre Vandergheynst
Accelerated Spectral Clustering Using Graph Filtering Of Random Signals
null
null
null
null
cs.SI cs.NA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We build upon recent advances in graph signal processing to propose a faster spectral clustering algorithm. Indeed, classical spectral clustering is based on the computation of the first k eigenvectors of the similarity matrix' Laplacian, whose computation cost, even for sparse matrices, becomes prohibitive for large datasets. We show that we can estimate the spectral clustering distance matrix without computing these eigenvectors: by graph filtering random signals. Also, we take advantage of the stochasticity of these random vectors to estimate the number of clusters k. We compare our method to classical spectral clustering on synthetic data, and show that it reaches equal performance while being faster by a factor at least two for large datasets.
[ { "version": "v1", "created": "Tue, 29 Sep 2015 17:32:48 GMT" } ]
2015-09-30T00:00:00
[ [ "Tremblay", "Nicolas", "" ], [ "Puy", "Gilles", "" ], [ "Borgnat", "Pierre", "" ], [ "Gribonval", "Remi", "" ], [ "Vandergheynst", "Pierre", "" ] ]
TITLE: Accelerated Spectral Clustering Using Graph Filtering Of Random Signals ABSTRACT: We build upon recent advances in graph signal processing to propose a faster spectral clustering algorithm. Indeed, classical spectral clustering is based on the computation of the first k eigenvectors of the similarity matrix' Laplacian, whose computation cost, even for sparse matrices, becomes prohibitive for large datasets. We show that we can estimate the spectral clustering distance matrix without computing these eigenvectors: by graph filtering random signals. Also, we take advantage of the stochasticity of these random vectors to estimate the number of clusters k. We compare our method to classical spectral clustering on synthetic data, and show that it reaches equal performance while being faster by a factor at least two for large datasets.
no_new_dataset
0.95452
1509.08888
Hamid Reza Hassanzadeh
Hamid Reza Hassanzadeh and John H. Phan and May D. Wang
A Semi-Supervised Method for Predicting Cancer Survival Using Incomplete Clinical Data
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Prediction of survival for cancer patients is an open area of research. However, many of these studies focus on datasets with a large number of patients. We present a novel method that is specifically designed to address the challenge of data scarcity, which is often the case for cancer datasets. Our method is able to use unlabeled data to improve classification by adopting a semi-supervised training approach to learn an ensemble classifier. The results of applying our method to three cancer datasets show the promise of semi-supervised learning for prediction of cancer survival.
[ { "version": "v1", "created": "Tue, 29 Sep 2015 18:53:04 GMT" } ]
2015-09-30T00:00:00
[ [ "Hassanzadeh", "Hamid Reza", "" ], [ "Phan", "John H.", "" ], [ "Wang", "May D.", "" ] ]
TITLE: A Semi-Supervised Method for Predicting Cancer Survival Using Incomplete Clinical Data ABSTRACT: Prediction of survival for cancer patients is an open area of research. However, many of these studies focus on datasets with a large number of patients. We present a novel method that is specifically designed to address the challenge of data scarcity, which is often the case for cancer datasets. Our method is able to use unlabeled data to improve classification by adopting a semi-supervised training approach to learn an ensemble classifier. The results of applying our method to three cancer datasets show the promise of semi-supervised learning for prediction of cancer survival.
no_new_dataset
0.953794
1509.08902
Gaurav Sharma
Gaurav Sharma and Bernt Schiele
Scalable Nonlinear Embeddings for Semantic Category-based Image Retrieval
ICCV 2015 preprint
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a novel algorithm for the task of supervised discriminative distance learning by nonlinearly embedding vectors into a low dimensional Euclidean space. We work in the challenging setting where supervision is with constraints on similar and dissimilar pairs while training. The proposed method is derived by an approximate kernelization of a linear Mahalanobis-like distance metric learning algorithm and can also be seen as a kernel neural network. The number of model parameters and test time evaluation complexity of the proposed method are O(dD) where D is the dimensionality of the input features and d is the dimension of the projection space - this is in contrast to the usual kernelization methods as, unlike them, the complexity does not scale linearly with the number of training examples. We propose a stochastic gradient based learning algorithm which makes the method scalable (w.r.t. the number of training examples), while being nonlinear. We train the method with up to half a million training pairs of 4096 dimensional CNN features. We give empirical comparisons with relevant baselines on seven challenging datasets for the task of low dimensional semantic category based image retrieval.
[ { "version": "v1", "created": "Tue, 29 Sep 2015 19:41:33 GMT" } ]
2015-09-30T00:00:00
[ [ "Sharma", "Gaurav", "" ], [ "Schiele", "Bernt", "" ] ]
TITLE: Scalable Nonlinear Embeddings for Semantic Category-based Image Retrieval ABSTRACT: We propose a novel algorithm for the task of supervised discriminative distance learning by nonlinearly embedding vectors into a low dimensional Euclidean space. We work in the challenging setting where supervision is with constraints on similar and dissimilar pairs while training. The proposed method is derived by an approximate kernelization of a linear Mahalanobis-like distance metric learning algorithm and can also be seen as a kernel neural network. The number of model parameters and test time evaluation complexity of the proposed method are O(dD) where D is the dimensionality of the input features and d is the dimension of the projection space - this is in contrast to the usual kernelization methods as, unlike them, the complexity does not scale linearly with the number of training examples. We propose a stochastic gradient based learning algorithm which makes the method scalable (w.r.t. the number of training examples), while being nonlinear. We train the method with up to half a million training pairs of 4096 dimensional CNN features. We give empirical comparisons with relevant baselines on seven challenging datasets for the task of low dimensional semantic category based image retrieval.
no_new_dataset
0.943815
1310.6767
Yogesh Girdhar Yogesh Girdhar
Yogesh Girdhar, David Whitney, and Gregory Dudek
Curiosity Based Exploration for Learning Terrain Models
7 pages, 5 figures, submitted to ICRA 2014
null
10.1109/ICRA.2014.6906913
null
cs.RO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a robotic exploration technique in which the goal is to learn to a visual model and be able to distinguish between different terrains and other visual components in an unknown environment. We use ROST, a realtime online spatiotemporal topic modeling framework to model these terrains using the observations made by the robot, and then use an information theoretic path planning technique to define the exploration path. We conduct experiments with aerial view and underwater datasets with millions of observations and varying path lengths, and find that paths that are biased towards locations with high topic perplexity produce better terrain models with high discriminative power, especially with paths of length close to the diameter of the world.
[ { "version": "v1", "created": "Thu, 24 Oct 2013 20:31:49 GMT" } ]
2015-09-29T00:00:00
[ [ "Girdhar", "Yogesh", "" ], [ "Whitney", "David", "" ], [ "Dudek", "Gregory", "" ] ]
TITLE: Curiosity Based Exploration for Learning Terrain Models ABSTRACT: We present a robotic exploration technique in which the goal is to learn to a visual model and be able to distinguish between different terrains and other visual components in an unknown environment. We use ROST, a realtime online spatiotemporal topic modeling framework to model these terrains using the observations made by the robot, and then use an information theoretic path planning technique to define the exploration path. We conduct experiments with aerial view and underwater datasets with millions of observations and varying path lengths, and find that paths that are biased towards locations with high topic perplexity produce better terrain models with high discriminative power, especially with paths of length close to the diameter of the world.
no_new_dataset
0.951549
1401.0702
Massimo Cafaro
Massimo Cafaro, Marco Pulimeno and Piergiulio Tempesta
A Parallel Space Saving Algorithm For Frequent Items and the Hurwitz zeta distribution
Accepted for publication. To appear in Information Sciences, Elsevier. http://www.sciencedirect.com/science/article/pii/S002002551500657X
Information Sciences, Elsevier, Volume 329, 2016, pp. 1 - 19, ISSN: 0020-0255
10.1016/j.ins.2015.09.003
null
cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a message-passing based parallel version of the Space Saving algorithm designed to solve the $k$--majority problem. The algorithm determines in parallel frequent items, i.e., those whose frequency is greater than a given threshold, and is therefore useful for iceberg queries and many other different contexts. We apply our algorithm to the detection of frequent items in both real and synthetic datasets whose probability distribution functions are a Hurwitz and a Zipf distribution respectively. Also, we compare its parallel performances and accuracy against a parallel algorithm recently proposed for merging summaries derived by the Space Saving or Frequent algorithms.
[ { "version": "v1", "created": "Fri, 3 Jan 2014 19:34:14 GMT" }, { "version": "v10", "created": "Thu, 13 Aug 2015 07:59:35 GMT" }, { "version": "v11", "created": "Thu, 3 Sep 2015 08:16:34 GMT" }, { "version": "v12", "created": "Sat, 19 Sep 2015 13:34:20 GMT" }, { "version": "v2", "created": "Mon, 6 Jan 2014 09:31:45 GMT" }, { "version": "v3", "created": "Tue, 21 Jan 2014 17:03:52 GMT" }, { "version": "v4", "created": "Mon, 19 May 2014 15:01:57 GMT" }, { "version": "v5", "created": "Tue, 7 Oct 2014 21:17:35 GMT" }, { "version": "v6", "created": "Wed, 3 Dec 2014 16:21:00 GMT" }, { "version": "v7", "created": "Mon, 15 Jun 2015 13:21:55 GMT" }, { "version": "v8", "created": "Tue, 16 Jun 2015 10:24:26 GMT" }, { "version": "v9", "created": "Sun, 2 Aug 2015 09:18:00 GMT" } ]
2015-09-29T00:00:00
[ [ "Cafaro", "Massimo", "" ], [ "Pulimeno", "Marco", "" ], [ "Tempesta", "Piergiulio", "" ] ]
TITLE: A Parallel Space Saving Algorithm For Frequent Items and the Hurwitz zeta distribution ABSTRACT: We present a message-passing based parallel version of the Space Saving algorithm designed to solve the $k$--majority problem. The algorithm determines in parallel frequent items, i.e., those whose frequency is greater than a given threshold, and is therefore useful for iceberg queries and many other different contexts. We apply our algorithm to the detection of frequent items in both real and synthetic datasets whose probability distribution functions are a Hurwitz and a Zipf distribution respectively. Also, we compare its parallel performances and accuracy against a parallel algorithm recently proposed for merging summaries derived by the Space Saving or Frequent algorithms.
no_new_dataset
0.953057
1501.07359
Tianfu Wu
Tianfu Wu and Bo Li and Song-Chun Zhu
Learning And-Or Models to Represent Context and Occlusion for Car Detection and Viewpoint Estimation
14 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents a method for learning And-Or models to represent context and occlusion for car detection and viewpoint estimation. The learned And-Or model represents car-to-car context and occlusion configurations at three levels: (i) spatially-aligned cars, (ii) single car under different occlusion configurations, and (iii) a small number of parts. The And-Or model embeds a grammar for representing large structural and appearance variations in a reconfigurable hierarchy. The learning process consists of two stages in a weakly supervised way (i.e., only bounding boxes of single cars are annotated). Firstly, the structure of the And-Or model is learned with three components: (a) mining multi-car contextual patterns based on layouts of annotated single car bounding boxes, (b) mining occlusion configurations between single cars, and (c) learning different combinations of part visibility based on car 3D CAD simulation. The And-Or model is organized in a directed and acyclic graph which can be inferred by Dynamic Programming. Secondly, the model parameters (for appearance, deformation and bias) are jointly trained using Weak-Label Structural SVM. In experiments, we test our model on four car detection datasets --- the KITTI dataset \cite{Geiger12}, the PASCAL VOC2007 car dataset~\cite{pascal}, and two self-collected car datasets, namely the Street-Parking car dataset and the Parking-Lot car dataset, and three datasets for car viewpoint estimation --- the PASCAL VOC2006 car dataset~\cite{pascal}, the 3D car dataset~\cite{savarese}, and the PASCAL3D+ car dataset~\cite{xiang_wacv14}. Compared with state-of-the-art variants of deformable part-based models and other methods, our model achieves significant improvement consistently on the four detection datasets, and comparable performance on car viewpoint estimation.
[ { "version": "v1", "created": "Thu, 29 Jan 2015 07:30:13 GMT" }, { "version": "v2", "created": "Sun, 27 Sep 2015 08:25:35 GMT" } ]
2015-09-29T00:00:00
[ [ "Wu", "Tianfu", "" ], [ "Li", "Bo", "" ], [ "Zhu", "Song-Chun", "" ] ]
TITLE: Learning And-Or Models to Represent Context and Occlusion for Car Detection and Viewpoint Estimation ABSTRACT: This paper presents a method for learning And-Or models to represent context and occlusion for car detection and viewpoint estimation. The learned And-Or model represents car-to-car context and occlusion configurations at three levels: (i) spatially-aligned cars, (ii) single car under different occlusion configurations, and (iii) a small number of parts. The And-Or model embeds a grammar for representing large structural and appearance variations in a reconfigurable hierarchy. The learning process consists of two stages in a weakly supervised way (i.e., only bounding boxes of single cars are annotated). Firstly, the structure of the And-Or model is learned with three components: (a) mining multi-car contextual patterns based on layouts of annotated single car bounding boxes, (b) mining occlusion configurations between single cars, and (c) learning different combinations of part visibility based on car 3D CAD simulation. The And-Or model is organized in a directed and acyclic graph which can be inferred by Dynamic Programming. Secondly, the model parameters (for appearance, deformation and bias) are jointly trained using Weak-Label Structural SVM. In experiments, we test our model on four car detection datasets --- the KITTI dataset \cite{Geiger12}, the PASCAL VOC2007 car dataset~\cite{pascal}, and two self-collected car datasets, namely the Street-Parking car dataset and the Parking-Lot car dataset, and three datasets for car viewpoint estimation --- the PASCAL VOC2006 car dataset~\cite{pascal}, the 3D car dataset~\cite{savarese}, and the PASCAL3D+ car dataset~\cite{xiang_wacv14}. Compared with state-of-the-art variants of deformable part-based models and other methods, our model achieves significant improvement consistently on the four detection datasets, and comparable performance on car viewpoint estimation.
no_new_dataset
0.917783
1502.07428
Elad Liebman
Elad Liebman, Benny Chor and Peter Stone
Representative Selection in Non Metric Datasets
null
null
10.1080/08839514.2015.1071092
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper considers the problem of representative selection: choosing a subset of data points from a dataset that best represents its overall set of elements. This subset needs to inherently reflect the type of information contained in the entire set, while minimizing redundancy. For such purposes, clustering may seem like a natural approach. However, existing clustering methods are not ideally suited for representative selection, especially when dealing with non-metric data, where only a pairwise similarity measure exists. In this paper we propose $\delta$-medoids, a novel approach that can be viewed as an extension to the $k$-medoids algorithm and is specifically suited for sample representative selection from non-metric data. We empirically validate $\delta$-medoids in two domains, namely music analysis and motion analysis. We also show some theoretical bounds on the performance of $\delta$-medoids and the hardness of representative selection in general.
[ { "version": "v1", "created": "Thu, 26 Feb 2015 04:16:31 GMT" }, { "version": "v2", "created": "Fri, 19 Jun 2015 22:44:29 GMT" } ]
2015-09-29T00:00:00
[ [ "Liebman", "Elad", "" ], [ "Chor", "Benny", "" ], [ "Stone", "Peter", "" ] ]
TITLE: Representative Selection in Non Metric Datasets ABSTRACT: This paper considers the problem of representative selection: choosing a subset of data points from a dataset that best represents its overall set of elements. This subset needs to inherently reflect the type of information contained in the entire set, while minimizing redundancy. For such purposes, clustering may seem like a natural approach. However, existing clustering methods are not ideally suited for representative selection, especially when dealing with non-metric data, where only a pairwise similarity measure exists. In this paper we propose $\delta$-medoids, a novel approach that can be viewed as an extension to the $k$-medoids algorithm and is specifically suited for sample representative selection from non-metric data. We empirically validate $\delta$-medoids in two domains, namely music analysis and motion analysis. We also show some theoretical bounds on the performance of $\delta$-medoids and the hardness of representative selection in general.
no_new_dataset
0.947186
1505.00256
Chenyi Chen
Chenyi Chen, Ari Seff, Alain Kornhauser, Jianxiong Xiao
DeepDriving: Learning Affordance for Direct Perception in Autonomous Driving
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Today, there are two major paradigms for vision-based autonomous driving systems: mediated perception approaches that parse an entire scene to make a driving decision, and behavior reflex approaches that directly map an input image to a driving action by a regressor. In this paper, we propose a third paradigm: a direct perception approach to estimate the affordance for driving. We propose to map an input image to a small number of key perception indicators that directly relate to the affordance of a road/traffic state for driving. Our representation provides a set of compact yet complete descriptions of the scene to enable a simple controller to drive autonomously. Falling in between the two extremes of mediated perception and behavior reflex, we argue that our direct perception representation provides the right level of abstraction. To demonstrate this, we train a deep Convolutional Neural Network using recording from 12 hours of human driving in a video game and show that our model can work well to drive a car in a very diverse set of virtual environments. We also train a model for car distance estimation on the KITTI dataset. Results show that our direct perception approach can generalize well to real driving images. Source code and data are available on our project website.
[ { "version": "v1", "created": "Fri, 1 May 2015 19:31:13 GMT" }, { "version": "v2", "created": "Mon, 4 May 2015 16:25:38 GMT" }, { "version": "v3", "created": "Sat, 26 Sep 2015 05:17:59 GMT" } ]
2015-09-29T00:00:00
[ [ "Chen", "Chenyi", "" ], [ "Seff", "Ari", "" ], [ "Kornhauser", "Alain", "" ], [ "Xiao", "Jianxiong", "" ] ]
TITLE: DeepDriving: Learning Affordance for Direct Perception in Autonomous Driving ABSTRACT: Today, there are two major paradigms for vision-based autonomous driving systems: mediated perception approaches that parse an entire scene to make a driving decision, and behavior reflex approaches that directly map an input image to a driving action by a regressor. In this paper, we propose a third paradigm: a direct perception approach to estimate the affordance for driving. We propose to map an input image to a small number of key perception indicators that directly relate to the affordance of a road/traffic state for driving. Our representation provides a set of compact yet complete descriptions of the scene to enable a simple controller to drive autonomously. Falling in between the two extremes of mediated perception and behavior reflex, we argue that our direct perception representation provides the right level of abstraction. To demonstrate this, we train a deep Convolutional Neural Network using recording from 12 hours of human driving in a video game and show that our model can work well to drive a car in a very diverse set of virtual environments. We also train a model for car distance estimation on the KITTI dataset. Results show that our direct perception approach can generalize well to real driving images. Source code and data are available on our project website.
no_new_dataset
0.944995
1506.01760
Yuchi Ma
Yuchi Ma and Ning Yang and Chuan Li and Lei Zhang and Philip S. Yu
Predicting Neighbor Distribution in Heterogeneous Information Networks
null
null
null
null
cs.SI physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recently, considerable attention has been devoted to the prediction problems arising from heterogeneous information networks. In this paper, we present a new prediction task, Neighbor Distribution Prediction (NDP), which aims at predicting the distribution of the labels on neighbors of a given node and is valuable for many different applications in heterogeneous information networks. The challenges of NDP mainly come from three aspects: the infinity of the state space of a neighbor distribution, the sparsity of available data, and how to fairly evaluate the predictions. To address these challenges, we first propose an Evolution Factor Model (EFM) for NDP, which utilizes two new structures proposed in this paper, i.e. Neighbor Distribution Vector (NDV) to represent the state of a given node's neighbors, and Neighbor Label Evolution Matrix (NLEM) to capture the dynamics of a neighbor distribution, respectively. We further propose a learning algorithm for Evolution Factor Model. To overcome the problem of data sparsity, the learning algorithm first clusters all the nodes and learns an NLEM for each cluster instead of for each node. For fairly evaluating the predicting results, we propose a new metric: Virtual Accuracy (VA), which takes into consideration both the absolute accuracy and the predictability of a node. Extensive experiments conducted on three real datasets from different domains validate the effectiveness of our proposed model EFM and metric VA.
[ { "version": "v1", "created": "Fri, 5 Jun 2015 01:13:54 GMT" } ]
2015-09-29T00:00:00
[ [ "Ma", "Yuchi", "" ], [ "Yang", "Ning", "" ], [ "Li", "Chuan", "" ], [ "Zhang", "Lei", "" ], [ "Yu", "Philip S.", "" ] ]
TITLE: Predicting Neighbor Distribution in Heterogeneous Information Networks ABSTRACT: Recently, considerable attention has been devoted to the prediction problems arising from heterogeneous information networks. In this paper, we present a new prediction task, Neighbor Distribution Prediction (NDP), which aims at predicting the distribution of the labels on neighbors of a given node and is valuable for many different applications in heterogeneous information networks. The challenges of NDP mainly come from three aspects: the infinity of the state space of a neighbor distribution, the sparsity of available data, and how to fairly evaluate the predictions. To address these challenges, we first propose an Evolution Factor Model (EFM) for NDP, which utilizes two new structures proposed in this paper, i.e. Neighbor Distribution Vector (NDV) to represent the state of a given node's neighbors, and Neighbor Label Evolution Matrix (NLEM) to capture the dynamics of a neighbor distribution, respectively. We further propose a learning algorithm for Evolution Factor Model. To overcome the problem of data sparsity, the learning algorithm first clusters all the nodes and learns an NLEM for each cluster instead of for each node. For fairly evaluating the predicting results, we propose a new metric: Virtual Accuracy (VA), which takes into consideration both the absolute accuracy and the predictability of a node. Extensive experiments conducted on three real datasets from different domains validate the effectiveness of our proposed model EFM and metric VA.
no_new_dataset
0.949201
1506.01929
Philippe Weinzaepfel
Philippe Weinzaepfel, Zaid Harchaoui, Cordelia Schmid
Learning to track for spatio-temporal action localization
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose an effective approach for spatio-temporal action localization in realistic videos. The approach first detects proposals at the frame-level and scores them with a combination of static and motion CNN features. It then tracks high-scoring proposals throughout the video using a tracking-by-detection approach. Our tracker relies simultaneously on instance-level and class-level detectors. The tracks are scored using a spatio-temporal motion histogram, a descriptor at the track level, in combination with the CNN features. Finally, we perform temporal localization of the action using a sliding-window approach at the track level. We present experimental results for spatio-temporal localization on the UCF-Sports, J-HMDB and UCF-101 action localization datasets, where our approach outperforms the state of the art with a margin of 15%, 7% and 12% respectively in mAP.
[ { "version": "v1", "created": "Fri, 5 Jun 2015 14:48:46 GMT" }, { "version": "v2", "created": "Sun, 27 Sep 2015 11:21:16 GMT" } ]
2015-09-29T00:00:00
[ [ "Weinzaepfel", "Philippe", "" ], [ "Harchaoui", "Zaid", "" ], [ "Schmid", "Cordelia", "" ] ]
TITLE: Learning to track for spatio-temporal action localization ABSTRACT: We propose an effective approach for spatio-temporal action localization in realistic videos. The approach first detects proposals at the frame-level and scores them with a combination of static and motion CNN features. It then tracks high-scoring proposals throughout the video using a tracking-by-detection approach. Our tracker relies simultaneously on instance-level and class-level detectors. The tracks are scored using a spatio-temporal motion histogram, a descriptor at the track level, in combination with the CNN features. Finally, we perform temporal localization of the action using a sliding-window approach at the track level. We present experimental results for spatio-temporal localization on the UCF-Sports, J-HMDB and UCF-101 action localization datasets, where our approach outperforms the state of the art with a margin of 15%, 7% and 12% respectively in mAP.
no_new_dataset
0.951142
1509.04767
Ziming Zhang
Ziming Zhang and Venkatesh Saligrama
Zero-Shot Learning via Semantic Similarity Embedding
accepted for ICCV 2015
null
null
null
cs.CV stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we consider a version of the zero-shot learning problem where seen class source and target domain data are provided. The goal during test-time is to accurately predict the class label of an unseen target domain instance based on revealed source domain side information (\eg attributes) for unseen classes. Our method is based on viewing each source or target data as a mixture of seen class proportions and we postulate that the mixture patterns have to be similar if the two instances belong to the same unseen class. This perspective leads us to learning source/target embedding functions that map an arbitrary source/target domain data into a same semantic space where similarity can be readily measured. We develop a max-margin framework to learn these similarity functions and jointly optimize parameters by means of cross validation. Our test results are compelling, leading to significant improvement in terms of accuracy on most benchmark datasets for zero-shot recognition.
[ { "version": "v1", "created": "Tue, 15 Sep 2015 23:18:52 GMT" }, { "version": "v2", "created": "Fri, 25 Sep 2015 20:26:08 GMT" } ]
2015-09-29T00:00:00
[ [ "Zhang", "Ziming", "" ], [ "Saligrama", "Venkatesh", "" ] ]
TITLE: Zero-Shot Learning via Semantic Similarity Embedding ABSTRACT: In this paper we consider a version of the zero-shot learning problem where seen class source and target domain data are provided. The goal during test-time is to accurately predict the class label of an unseen target domain instance based on revealed source domain side information (\eg attributes) for unseen classes. Our method is based on viewing each source or target data as a mixture of seen class proportions and we postulate that the mixture patterns have to be similar if the two instances belong to the same unseen class. This perspective leads us to learning source/target embedding functions that map an arbitrary source/target domain data into a same semantic space where similarity can be readily measured. We develop a max-margin framework to learn these similarity functions and jointly optimize parameters by means of cross validation. Our test results are compelling, leading to significant improvement in terms of accuracy on most benchmark datasets for zero-shot recognition.
no_new_dataset
0.952618
1509.05490
Han Xiao Bookman
Han Xiao, Minlie Huang, Yu Hao, Xiaoyan Zhu
TransA: An Adaptive Approach for Knowledge Graph Embedding
null
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Knowledge representation is a major topic in AI, and many studies attempt to represent entities and relations of knowledge base in a continuous vector space. Among these attempts, translation-based methods build entity and relation vectors by minimizing the translation loss from a head entity to a tail one. In spite of the success of these methods, translation-based methods also suffer from the oversimplified loss metric, and are not competitive enough to model various and complex entities/relations in knowledge bases. To address this issue, we propose \textbf{TransA}, an adaptive metric approach for embedding, utilizing the metric learning ideas to provide a more flexible embedding method. Experiments are conducted on the benchmark datasets and our proposed method makes significant and consistent improvements over the state-of-the-art baselines.
[ { "version": "v1", "created": "Fri, 18 Sep 2015 02:40:07 GMT" }, { "version": "v2", "created": "Mon, 28 Sep 2015 02:21:20 GMT" } ]
2015-09-29T00:00:00
[ [ "Xiao", "Han", "" ], [ "Huang", "Minlie", "" ], [ "Hao", "Yu", "" ], [ "Zhu", "Xiaoyan", "" ] ]
TITLE: TransA: An Adaptive Approach for Knowledge Graph Embedding ABSTRACT: Knowledge representation is a major topic in AI, and many studies attempt to represent entities and relations of knowledge base in a continuous vector space. Among these attempts, translation-based methods build entity and relation vectors by minimizing the translation loss from a head entity to a tail one. In spite of the success of these methods, translation-based methods also suffer from the oversimplified loss metric, and are not competitive enough to model various and complex entities/relations in knowledge bases. To address this issue, we propose \textbf{TransA}, an adaptive metric approach for embedding, utilizing the metric learning ideas to provide a more flexible embedding method. Experiments are conducted on the benchmark datasets and our proposed method makes significant and consistent improvements over the state-of-the-art baselines.
no_new_dataset
0.94474
1509.06114
Inwook Shim
Inwook Shim, Seunghak Shin, Yunsu Bok, Kyungdon Joo, Dong-Geol Choi, Joon-Young Lee, Jaesik Park, Jun-Ho Oh, In So Kweon
Vision System and Depth Processing for DRC-HUBO+
submitted in ICRA 2016
null
null
null
cs.CV cs.RO
http://creativecommons.org/licenses/by/4.0/
This paper presents a vision system and a depth processing algorithm for DRC-HUBO+, the winner of the DRC finals 2015. Our system is designed to reliably capture 3D information of a scene and objects robust to challenging environment conditions. We also propose a depth-map upsampling method that produces an outliers-free depth map by explicitly handling depth outliers. Our system is suitable for an interactive robot with real-world that requires accurate object detection and pose estimation. We evaluate our depth processing algorithm over state-of-the-art algorithms on several synthetic and real-world datasets.
[ { "version": "v1", "created": "Mon, 21 Sep 2015 06:17:21 GMT" }, { "version": "v2", "created": "Mon, 28 Sep 2015 15:05:37 GMT" } ]
2015-09-29T00:00:00
[ [ "Shim", "Inwook", "" ], [ "Shin", "Seunghak", "" ], [ "Bok", "Yunsu", "" ], [ "Joo", "Kyungdon", "" ], [ "Choi", "Dong-Geol", "" ], [ "Lee", "Joon-Young", "" ], [ "Park", "Jaesik", "" ], [ "Oh", "Jun-Ho", "" ], [ "Kweon", "In So", "" ] ]
TITLE: Vision System and Depth Processing for DRC-HUBO+ ABSTRACT: This paper presents a vision system and a depth processing algorithm for DRC-HUBO+, the winner of the DRC finals 2015. Our system is designed to reliably capture 3D information of a scene and objects robust to challenging environment conditions. We also propose a depth-map upsampling method that produces an outliers-free depth map by explicitly handling depth outliers. Our system is suitable for an interactive robot with real-world that requires accurate object detection and pose estimation. We evaluate our depth processing algorithm over state-of-the-art algorithms on several synthetic and real-world datasets.
no_new_dataset
0.951639
1509.07266
Smita Roy
Smita Roy, Samrat Mondal and Asif Ekbal
CRDT: Correlation Ratio Based Decision Tree Model for Healthcare Data Mining
null
null
null
null
cs.AI cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The phenomenal growth in the healthcare data has inspired us in investigating robust and scalable models for data mining. For classification problems Information Gain(IG) based Decision Tree is one of the popular choices. However, depending upon the nature of the dataset, IG based Decision Tree may not always perform well as it prefers the attribute with more number of distinct values as the splitting attribute. Healthcare datasets generally have many attributes and each attribute generally has many distinct values. In this paper, we have tried to focus on this characteristics of the datasets while analysing the performance of our proposed approach which is a variant of Decision Tree model and uses the concept of Correlation Ratio(CR). Unlike IG based approach, this CR based approach has no biasness towards the attribute with more number of distinct values. We have applied our model on some benchmark healthcare datasets to show the effectiveness of the proposed technique.
[ { "version": "v1", "created": "Thu, 24 Sep 2015 07:57:27 GMT" } ]
2015-09-29T00:00:00
[ [ "Roy", "Smita", "" ], [ "Mondal", "Samrat", "" ], [ "Ekbal", "Asif", "" ] ]
TITLE: CRDT: Correlation Ratio Based Decision Tree Model for Healthcare Data Mining ABSTRACT: The phenomenal growth in the healthcare data has inspired us in investigating robust and scalable models for data mining. For classification problems Information Gain(IG) based Decision Tree is one of the popular choices. However, depending upon the nature of the dataset, IG based Decision Tree may not always perform well as it prefers the attribute with more number of distinct values as the splitting attribute. Healthcare datasets generally have many attributes and each attribute generally has many distinct values. In this paper, we have tried to focus on this characteristics of the datasets while analysing the performance of our proposed approach which is a variant of Decision Tree model and uses the concept of Correlation Ratio(CR). Unlike IG based approach, this CR based approach has no biasness towards the attribute with more number of distinct values. We have applied our model on some benchmark healthcare datasets to show the effectiveness of the proposed technique.
no_new_dataset
0.956227
1509.07479
Michael Wilber
Michael J. Wilber, Iljung S. Kwak, David Kriegman, Serge Belongie
Learning Concept Embeddings with Combined Human-Machine Expertise
To appear at ICCV 2015. (This version has updated author affiliations and updated footnotes.)
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents our work on "SNaCK," a low-dimensional concept embedding algorithm that combines human expertise with automatic machine similarity kernels. Both parts are complimentary: human insight can capture relationships that are not apparent from the object's visual similarity and the machine can help relieve the human from having to exhaustively specify many constraints. We show that our SNaCK embeddings are useful in several tasks: distinguishing prime and nonprime numbers on MNIST, discovering labeling mistakes in the Caltech UCSD Birds (CUB) dataset with the help of deep-learned features, creating training datasets for bird classifiers, capturing subjective human taste on a new dataset of 10,000 foods, and qualitatively exploring an unstructured set of pictographic characters. Comparisons with the state-of-the-art in these tasks show that SNaCK produces better concept embeddings that require less human supervision than the leading methods.
[ { "version": "v1", "created": "Thu, 24 Sep 2015 19:05:09 GMT" }, { "version": "v2", "created": "Mon, 28 Sep 2015 17:19:05 GMT" } ]
2015-09-29T00:00:00
[ [ "Wilber", "Michael J.", "" ], [ "Kwak", "Iljung S.", "" ], [ "Kriegman", "David", "" ], [ "Belongie", "Serge", "" ] ]
TITLE: Learning Concept Embeddings with Combined Human-Machine Expertise ABSTRACT: This paper presents our work on "SNaCK," a low-dimensional concept embedding algorithm that combines human expertise with automatic machine similarity kernels. Both parts are complimentary: human insight can capture relationships that are not apparent from the object's visual similarity and the machine can help relieve the human from having to exhaustively specify many constraints. We show that our SNaCK embeddings are useful in several tasks: distinguishing prime and nonprime numbers on MNIST, discovering labeling mistakes in the Caltech UCSD Birds (CUB) dataset with the help of deep-learned features, creating training datasets for bird classifiers, capturing subjective human taste on a new dataset of 10,000 foods, and qualitatively exploring an unstructured set of pictographic characters. Comparisons with the state-of-the-art in these tasks show that SNaCK produces better concept embeddings that require less human supervision than the leading methods.
new_dataset
0.958615
1509.07961
Vyacheslav Olshevsky
Vyacheslav Olshevsky, Andrey Divin, Elin Eriksson, Stefano Markidis, Giovanni Lapenta
Energy dissipation in magnetic null points at kinetic scales
null
The Astrophysical Journal, Volume 807, Issue 2, article id. 155, 11 pp. (2015)
10.1088/0004-637X/807/2/155
null
astro-ph.EP astro-ph.SR physics.plasm-ph physics.space-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We use kinetic particle-in-cell and magnetohydrodynamic simulations supported by an observational dataset to investigate magnetic reconnection in clusters of null points in space plasma. The magnetic configuration under investigation is driven by fast adiabatic flux rope compression that dissipates almost half of the initial magnetic field energy. In this phase powerful currents are excited producing secondary instabilities, and the system is brought into a state of `intermittent turbulence' within a few ion gyro-periods. Reconnection events are distributed all over the simulation domain and energy dissipation is rather volume-filling. Numerous spiral null points interconnected via their spines form null lines embedded into magnetic flux ropes; null point pairs demonstrate the signatures of torsional spine reconnection. However, energy dissipation mainly happens in the shear layers formed by adjacent flux ropes with oppositely directed currents. In these regions radial null pairs are spontaneously emerging and vanishing, associated with electron streams and small-scale current sheets. The number of spiral nulls in the simulation outweighs the number of radial nulls by a factor of 5\---10, in accordance with Cluster observations in the Earth's magnetosheath. Twisted magnetic fields with embedded spiral null points might indicate the regions of major energy dissipation for future space missions such as Magnetospheric Multiscale Mission (MMS).
[ { "version": "v1", "created": "Sat, 26 Sep 2015 11:20:19 GMT" } ]
2015-09-29T00:00:00
[ [ "Olshevsky", "Vyacheslav", "" ], [ "Divin", "Andrey", "" ], [ "Eriksson", "Elin", "" ], [ "Markidis", "Stefano", "" ], [ "Lapenta", "Giovanni", "" ] ]
TITLE: Energy dissipation in magnetic null points at kinetic scales ABSTRACT: We use kinetic particle-in-cell and magnetohydrodynamic simulations supported by an observational dataset to investigate magnetic reconnection in clusters of null points in space plasma. The magnetic configuration under investigation is driven by fast adiabatic flux rope compression that dissipates almost half of the initial magnetic field energy. In this phase powerful currents are excited producing secondary instabilities, and the system is brought into a state of `intermittent turbulence' within a few ion gyro-periods. Reconnection events are distributed all over the simulation domain and energy dissipation is rather volume-filling. Numerous spiral null points interconnected via their spines form null lines embedded into magnetic flux ropes; null point pairs demonstrate the signatures of torsional spine reconnection. However, energy dissipation mainly happens in the shear layers formed by adjacent flux ropes with oppositely directed currents. In these regions radial null pairs are spontaneously emerging and vanishing, associated with electron streams and small-scale current sheets. The number of spiral nulls in the simulation outweighs the number of radial nulls by a factor of 5\---10, in accordance with Cluster observations in the Earth's magnetosheath. Twisted magnetic fields with embedded spiral null points might indicate the regions of major energy dissipation for future space missions such as Magnetospheric Multiscale Mission (MMS).
no_new_dataset
0.952706
1509.07996
Yixuan Li
Yixuan Li, Kun He, David Bindel and John Hopcroft
Overlapping Community Detection via Local Spectral Clustering
Extended version to the conference proceeding in WWW'15
null
null
null
cs.SI cs.DS physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Large graphs arise in a number of contexts and understanding their structure and extracting information from them is an important research area. Early algorithms on mining communities have focused on the global structure, and often run in time functional to the size of the entire graph. Nowadays, as we often explore networks with billions of vertices and find communities of size hundreds, it is crucial to shift our attention from macroscopic structure to microscopic structure in large networks. A growing body of work has been adopting local expansion methods in order to identify the community members from a few exemplary seed members. In this paper, we propose a novel approach for finding overlapping communities called LEMON (Local Expansion via Minimum One Norm). The algorithm finds the community by seeking a sparse vector in the span of the local spectra such that the seeds are in its support. We show that LEMON can achieve the highest detection accuracy among state-of-the-art proposals. The running time depends on the size of the community rather than that of the entire graph. The algorithm is easy to implement, and is highly parallelizable. We further provide theoretical analysis on the local spectral properties, bounding the measure of tightness of extracted community in terms of the eigenvalues of graph Laplacian. Moreover, given that networks are not all similar in nature, a comprehensive analysis on how the local expansion approach is suited for uncovering communities in different networks is still lacking. We thoroughly evaluate our approach using both synthetic and real-world datasets across different domains, and analyze the empirical variations when applying our method to inherently different networks in practice. In addition, the heuristics on how the seed set quality and quantity would affect the performance are provided.
[ { "version": "v1", "created": "Sat, 26 Sep 2015 15:27:38 GMT" } ]
2015-09-29T00:00:00
[ [ "Li", "Yixuan", "" ], [ "He", "Kun", "" ], [ "Bindel", "David", "" ], [ "Hopcroft", "John", "" ] ]
TITLE: Overlapping Community Detection via Local Spectral Clustering ABSTRACT: Large graphs arise in a number of contexts and understanding their structure and extracting information from them is an important research area. Early algorithms on mining communities have focused on the global structure, and often run in time functional to the size of the entire graph. Nowadays, as we often explore networks with billions of vertices and find communities of size hundreds, it is crucial to shift our attention from macroscopic structure to microscopic structure in large networks. A growing body of work has been adopting local expansion methods in order to identify the community members from a few exemplary seed members. In this paper, we propose a novel approach for finding overlapping communities called LEMON (Local Expansion via Minimum One Norm). The algorithm finds the community by seeking a sparse vector in the span of the local spectra such that the seeds are in its support. We show that LEMON can achieve the highest detection accuracy among state-of-the-art proposals. The running time depends on the size of the community rather than that of the entire graph. The algorithm is easy to implement, and is highly parallelizable. We further provide theoretical analysis on the local spectral properties, bounding the measure of tightness of extracted community in terms of the eigenvalues of graph Laplacian. Moreover, given that networks are not all similar in nature, a comprehensive analysis on how the local expansion approach is suited for uncovering communities in different networks is still lacking. We thoroughly evaluate our approach using both synthetic and real-world datasets across different domains, and analyze the empirical variations when applying our method to inherently different networks in practice. In addition, the heuristics on how the seed set quality and quantity would affect the performance are provided.
no_new_dataset
0.94625
1509.08038
Wentao Zhu
Wentao Zhu, Jun Miao, Laiyun Qing, Xilin Chen
Deep Trans-layer Unsupervised Networks for Representation Learning
21 pages, 3 figures
null
null
null
cs.NE cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Learning features from massive unlabelled data is a vast prevalent topic for high-level tasks in many machine learning applications. The recent great improvements on benchmark data sets achieved by increasingly complex unsupervised learning methods and deep learning models with lots of parameters usually requires many tedious tricks and much expertise to tune. However, filters learned by these complex architectures are quite similar to standard hand-crafted features visually. In this paper, unsupervised learning methods, such as PCA or auto-encoder, are employed as the building block to learn filter banks at each layer. The lower layer responses are transferred to the last layer (trans-layer) to form a more complete representation retaining more information. In addition, some beneficial methods such as local contrast normalization and whitening are added to the proposed deep trans-layer networks to further boost performance. The trans-layer representations are followed by block histograms with binary encoder schema to learn translation and rotation invariant representations, which are utilized to do high-level tasks such as recognition and classification. Compared to traditional deep learning methods, the implemented feature learning method has much less parameters and is validated in several typical experiments, such as digit recognition on MNIST and MNIST variations, object recognition on Caltech 101 dataset and face verification on LFW dataset. The deep trans-layer unsupervised learning achieves 99.45% accuracy on MNIST dataset, 67.11% accuracy on 15 samples per class and 75.98% accuracy on 30 samples per class on Caltech 101 dataset, 87.10% on LFW dataset.
[ { "version": "v1", "created": "Sun, 27 Sep 2015 00:46:08 GMT" } ]
2015-09-29T00:00:00
[ [ "Zhu", "Wentao", "" ], [ "Miao", "Jun", "" ], [ "Qing", "Laiyun", "" ], [ "Chen", "Xilin", "" ] ]
TITLE: Deep Trans-layer Unsupervised Networks for Representation Learning ABSTRACT: Learning features from massive unlabelled data is a vast prevalent topic for high-level tasks in many machine learning applications. The recent great improvements on benchmark data sets achieved by increasingly complex unsupervised learning methods and deep learning models with lots of parameters usually requires many tedious tricks and much expertise to tune. However, filters learned by these complex architectures are quite similar to standard hand-crafted features visually. In this paper, unsupervised learning methods, such as PCA or auto-encoder, are employed as the building block to learn filter banks at each layer. The lower layer responses are transferred to the last layer (trans-layer) to form a more complete representation retaining more information. In addition, some beneficial methods such as local contrast normalization and whitening are added to the proposed deep trans-layer networks to further boost performance. The trans-layer representations are followed by block histograms with binary encoder schema to learn translation and rotation invariant representations, which are utilized to do high-level tasks such as recognition and classification. Compared to traditional deep learning methods, the implemented feature learning method has much less parameters and is validated in several typical experiments, such as digit recognition on MNIST and MNIST variations, object recognition on Caltech 101 dataset and face verification on LFW dataset. The deep trans-layer unsupervised learning achieves 99.45% accuracy on MNIST dataset, 67.11% accuracy on 15 samples per class and 75.98% accuracy on 30 samples per class on Caltech 101 dataset, 87.10% on LFW dataset.
no_new_dataset
0.950273
1509.08075
Hamid Izadinia
Hamid Izadinia, Fereshteh Sadeghi, Santosh Kumar Divvala, Yejin Choi, Ali Farhadi
Segment-Phrase Table for Semantic Segmentation, Visual Entailment and Paraphrasing
9 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce Segment-Phrase Table (SPT), a large collection of bijective associations between textual phrases and their corresponding segmentations. Leveraging recent progress in object recognition and natural language semantics, we show how we can successfully build a high-quality segment-phrase table using minimal human supervision. More importantly, we demonstrate the unique value unleashed by this rich bimodal resource, for both vision as well as natural language understanding. First, we show that fine-grained textual labels facilitate contextual reasoning that helps in satisfying semantic constraints across image segments. This feature enables us to achieve state-of-the-art segmentation results on benchmark datasets. Next, we show that the association of high-quality segmentations to textual phrases aids in richer semantic understanding and reasoning of these textual phrases. Leveraging this feature, we motivate the problem of visual entailment and visual paraphrasing, and demonstrate its utility on a large dataset.
[ { "version": "v1", "created": "Sun, 27 Sep 2015 10:01:42 GMT" } ]
2015-09-29T00:00:00
[ [ "Izadinia", "Hamid", "" ], [ "Sadeghi", "Fereshteh", "" ], [ "Divvala", "Santosh Kumar", "" ], [ "Choi", "Yejin", "" ], [ "Farhadi", "Ali", "" ] ]
TITLE: Segment-Phrase Table for Semantic Segmentation, Visual Entailment and Paraphrasing ABSTRACT: We introduce Segment-Phrase Table (SPT), a large collection of bijective associations between textual phrases and their corresponding segmentations. Leveraging recent progress in object recognition and natural language semantics, we show how we can successfully build a high-quality segment-phrase table using minimal human supervision. More importantly, we demonstrate the unique value unleashed by this rich bimodal resource, for both vision as well as natural language understanding. First, we show that fine-grained textual labels facilitate contextual reasoning that helps in satisfying semantic constraints across image segments. This feature enables us to achieve state-of-the-art segmentation results on benchmark datasets. Next, we show that the association of high-quality segmentations to textual phrases aids in richer semantic understanding and reasoning of these textual phrases. Leveraging this feature, we motivate the problem of visual entailment and visual paraphrasing, and demonstrate its utility on a large dataset.
no_new_dataset
0.938124
1509.08095
M\'arton Karsai
Laura Alessandretti, M\'arton Karsai, Laetitia Gauvin
User-based representation of time-resolved multimodal public transportation networks
24 pages, 8 figures
null
null
null
physics.soc-ph cs.SI physics.data-an
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multimodal transportation systems can be represented as time-resolved multilayer networks where different transportation modes connecting the same set of nodes are associated to distinct network layers. Their quantitative description became possible recently due to openly accessible datasets describing the geolocalised transportation dynamics of large urban areas. Advancements call for novel analytics, which combines earlier established methods and exploits the inherent complexity of the data. Here, our aim is to provide a novel user-based methodological framework to represent public transportation systems considering the total travel time, its variability across the schedule, and taking into account the number of transfers necessary. Using this framework we analyse public transportation systems in several French municipal areas. We incorporate travel routes and times over multiple transportation modes to identify efficient transportation connections and non-trivial connectivity patterns. The proposed method enables us to quantify the network's overall efficiency as compared to the specific demand and to the car alternative.
[ { "version": "v1", "created": "Sun, 27 Sep 2015 14:03:09 GMT" } ]
2015-09-29T00:00:00
[ [ "Alessandretti", "Laura", "" ], [ "Karsai", "Márton", "" ], [ "Gauvin", "Laetitia", "" ] ]
TITLE: User-based representation of time-resolved multimodal public transportation networks ABSTRACT: Multimodal transportation systems can be represented as time-resolved multilayer networks where different transportation modes connecting the same set of nodes are associated to distinct network layers. Their quantitative description became possible recently due to openly accessible datasets describing the geolocalised transportation dynamics of large urban areas. Advancements call for novel analytics, which combines earlier established methods and exploits the inherent complexity of the data. Here, our aim is to provide a novel user-based methodological framework to represent public transportation systems considering the total travel time, its variability across the schedule, and taking into account the number of transfers necessary. Using this framework we analyse public transportation systems in several French municipal areas. We incorporate travel routes and times over multiple transportation modes to identify efficient transportation connections and non-trivial connectivity patterns. The proposed method enables us to quantify the network's overall efficiency as compared to the specific demand and to the car alternative.
no_new_dataset
0.9455
1509.08197
Xuan Luo
Xuan Luo, Xuejiao Bai, Shuo Li, Hongtao Lu, Sei-ichiro Kamata
Fast Non-local Stereo Matching based on Hierarchical Disparity Prediction
9 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Stereo matching is the key step in estimating depth from two or more images. Recently, some tree-based non-local stereo matching methods have been proposed, which achieved state-of-the-art performance. The algorithms employed some tree structures to aggregate cost and thus improved the performance and reduced the coputation load of the stereo matching. However, the computational complexity of these tree-based algorithms is still high because they search over the entire disparity range. In addition, the extreme greediness of the minimum spanning tree (MST) causes the poor performance in large areas with similar colors but varying disparities. In this paper, we propose an efficient stereo matching method using a hierarchical disparity prediction (HDP) framework to dramatically reduce the disparity search range so as to speed up the tree-based non-local stereo methods. Our disparity prediction scheme works on a graph pyramid derived from an image whose disparity to be estimated. We utilize the disparity of a upper graph to predict a small disparity range for the lower graph. Some independent disparity trees (DT) are generated to form a disparity prediction forest (HDPF) over which the cost aggregation is made. When combined with the state-of-the-art tree-based methods, our scheme not only dramatically speeds up the original methods but also improves their performance by alleviating the second drawback of the tree-based methods. This is partially because our DTs overcome the extreme greediness of the MST. Extensive experimental results on some benchmark datasets demonstrate the effectiveness and efficiency of our framework. For example, the segment-tree based stereo matching becomes about 25.57 times faster and 2.2% more accurate over the Middlebury 2006 full-size dataset.
[ { "version": "v1", "created": "Mon, 28 Sep 2015 05:00:01 GMT" } ]
2015-09-29T00:00:00
[ [ "Luo", "Xuan", "" ], [ "Bai", "Xuejiao", "" ], [ "Li", "Shuo", "" ], [ "Lu", "Hongtao", "" ], [ "Kamata", "Sei-ichiro", "" ] ]
TITLE: Fast Non-local Stereo Matching based on Hierarchical Disparity Prediction ABSTRACT: Stereo matching is the key step in estimating depth from two or more images. Recently, some tree-based non-local stereo matching methods have been proposed, which achieved state-of-the-art performance. The algorithms employed some tree structures to aggregate cost and thus improved the performance and reduced the coputation load of the stereo matching. However, the computational complexity of these tree-based algorithms is still high because they search over the entire disparity range. In addition, the extreme greediness of the minimum spanning tree (MST) causes the poor performance in large areas with similar colors but varying disparities. In this paper, we propose an efficient stereo matching method using a hierarchical disparity prediction (HDP) framework to dramatically reduce the disparity search range so as to speed up the tree-based non-local stereo methods. Our disparity prediction scheme works on a graph pyramid derived from an image whose disparity to be estimated. We utilize the disparity of a upper graph to predict a small disparity range for the lower graph. Some independent disparity trees (DT) are generated to form a disparity prediction forest (HDPF) over which the cost aggregation is made. When combined with the state-of-the-art tree-based methods, our scheme not only dramatically speeds up the original methods but also improves their performance by alleviating the second drawback of the tree-based methods. This is partially because our DTs overcome the extreme greediness of the MST. Extensive experimental results on some benchmark datasets demonstrate the effectiveness and efficiency of our framework. For example, the segment-tree based stereo matching becomes about 25.57 times faster and 2.2% more accurate over the Middlebury 2006 full-size dataset.
no_new_dataset
0.95222
1509.08239
Biju Issac
Mohanad Albayati and Biju Issac
Analysis of Intelligent Classifiers and Enhancing the Detection Accuracy for Intrusion Detection System
null
International Journal of Computational Intelligence Systems, 8:5, 841-853 (2015)
10.1080/18756891.2015.1084705
null
cs.CR cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we discuss and analyze some of the intelligent classifiers which allows for automatic detection and classification of networks attacks for any intrusion detection system. We will proceed initially with their analysis using the WEKA software to work with the classifiers on a well-known IDS (Intrusion Detection Systems) dataset like NSL-KDD dataset. The NSL-KDD dataset of network attacks was created in a military network by MIT Lincoln Labs. Then we will discuss and experiment some of the hybrid AI (Artificial Intelligence) classifiers that can be used for IDS, and finally we developed a Java software with three most efficient classifiers and compared it with other options. The outputs would show the detection accuracy and efficiency of the single and combined classifiers used.
[ { "version": "v1", "created": "Mon, 28 Sep 2015 09:01:30 GMT" } ]
2015-09-29T00:00:00
[ [ "Albayati", "Mohanad", "" ], [ "Issac", "Biju", "" ] ]
TITLE: Analysis of Intelligent Classifiers and Enhancing the Detection Accuracy for Intrusion Detection System ABSTRACT: In this paper we discuss and analyze some of the intelligent classifiers which allows for automatic detection and classification of networks attacks for any intrusion detection system. We will proceed initially with their analysis using the WEKA software to work with the classifiers on a well-known IDS (Intrusion Detection Systems) dataset like NSL-KDD dataset. The NSL-KDD dataset of network attacks was created in a military network by MIT Lincoln Labs. Then we will discuss and experiment some of the hybrid AI (Artificial Intelligence) classifiers that can be used for IDS, and finally we developed a Java software with three most efficient classifiers and compared it with other options. The outputs would show the detection accuracy and efficiency of the single and combined classifiers used.
new_dataset
0.940953
1509.08360
Dinesh Ramasamy
Dinesh Ramasamy and Upamanyu Madhow
Compressive spectral embedding: sidestepping the SVD
NIPS 2015
null
null
null
stat.ML cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Spectral embedding based on the Singular Value Decomposition (SVD) is a widely used "preprocessing" step in many learning tasks, typically leading to dimensionality reduction by projecting onto a number of dominant singular vectors and rescaling the coordinate axes (by a predefined function of the singular value). However, the number of such vectors required to capture problem structure grows with problem size, and even partial SVD computation becomes a bottleneck. In this paper, we propose a low-complexity it compressive spectral embedding algorithm, which employs random projections and finite order polynomial expansions to compute approximations to SVD-based embedding. For an m times n matrix with T non-zeros, its time complexity is O((T+m+n)log(m+n)), and the embedding dimension is O(log(m+n)), both of which are independent of the number of singular vectors whose effect we wish to capture. To the best of our knowledge, this is the first work to circumvent this dependence on the number of singular vectors for general SVD-based embeddings. The key to sidestepping the SVD is the observation that, for downstream inference tasks such as clustering and classification, we are only interested in using the resulting embedding to evaluate pairwise similarity metrics derived from the euclidean norm, rather than capturing the effect of the underlying matrix on arbitrary vectors as a partial SVD tries to do. Our numerical results on network datasets demonstrate the efficacy of the proposed method, and motivate further exploration of its application to large-scale inference tasks.
[ { "version": "v1", "created": "Mon, 28 Sep 2015 15:32:20 GMT" } ]
2015-09-29T00:00:00
[ [ "Ramasamy", "Dinesh", "" ], [ "Madhow", "Upamanyu", "" ] ]
TITLE: Compressive spectral embedding: sidestepping the SVD ABSTRACT: Spectral embedding based on the Singular Value Decomposition (SVD) is a widely used "preprocessing" step in many learning tasks, typically leading to dimensionality reduction by projecting onto a number of dominant singular vectors and rescaling the coordinate axes (by a predefined function of the singular value). However, the number of such vectors required to capture problem structure grows with problem size, and even partial SVD computation becomes a bottleneck. In this paper, we propose a low-complexity it compressive spectral embedding algorithm, which employs random projections and finite order polynomial expansions to compute approximations to SVD-based embedding. For an m times n matrix with T non-zeros, its time complexity is O((T+m+n)log(m+n)), and the embedding dimension is O(log(m+n)), both of which are independent of the number of singular vectors whose effect we wish to capture. To the best of our knowledge, this is the first work to circumvent this dependence on the number of singular vectors for general SVD-based embeddings. The key to sidestepping the SVD is the observation that, for downstream inference tasks such as clustering and classification, we are only interested in using the resulting embedding to evaluate pairwise similarity metrics derived from the euclidean norm, rather than capturing the effect of the underlying matrix on arbitrary vectors as a partial SVD tries to do. Our numerical results on network datasets demonstrate the efficacy of the proposed method, and motivate further exploration of its application to large-scale inference tasks.
no_new_dataset
0.946597
1509.08418
Zheng Li
Zheng Li and Liam O'Brien and Ye Yang
The more Product Complexity, the more Actual Effort? An Empirical Investigation into Software Developments
null
ASWEC 2014
null
null
cs.SE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
[Background:] Software effort prediction methods and models typically assume positive correlation between software product complexity and development effort. However, conflicting observations, i.e. negative correlation between product complexity and actual effort, have been witnessed from our experience with the COCOMO81 dataset. [Aim:] Given our doubt about whether the observed phenomenon is a coincidence, this study tries to investigate if an increase in product complexity can result in the abovementioned counter-intuitive trend in software development projects. [Method:] A modified association rule mining approach is applied to the transformed COCOMO81 dataset. To reduce noise of analysis, this approach uses a constant antecedent (Complexity increases while Effort decreases) to mine potential consequents with pruning. [Results:] The experiment has respectively mined four, five, and seven association rules from the general, embedded, and organic projects data. The consequents of the mined rules suggested two main aspects, namely human capability and product scale, to be particularly concerned in this study. [Conclusions:] The negative correlation between complexity and effort is not a coincidence under particular conditions. In a software project, interactions between product complexity and other factors, such as Programmer Capability and Analyst Capability, can inevitably play a "friction" role in weakening the practical influences of product complexity on actual development effort.
[ { "version": "v1", "created": "Mon, 28 Sep 2015 18:11:16 GMT" } ]
2015-09-29T00:00:00
[ [ "Li", "Zheng", "" ], [ "O'Brien", "Liam", "" ], [ "Yang", "Ye", "" ] ]
TITLE: The more Product Complexity, the more Actual Effort? An Empirical Investigation into Software Developments ABSTRACT: [Background:] Software effort prediction methods and models typically assume positive correlation between software product complexity and development effort. However, conflicting observations, i.e. negative correlation between product complexity and actual effort, have been witnessed from our experience with the COCOMO81 dataset. [Aim:] Given our doubt about whether the observed phenomenon is a coincidence, this study tries to investigate if an increase in product complexity can result in the abovementioned counter-intuitive trend in software development projects. [Method:] A modified association rule mining approach is applied to the transformed COCOMO81 dataset. To reduce noise of analysis, this approach uses a constant antecedent (Complexity increases while Effort decreases) to mine potential consequents with pruning. [Results:] The experiment has respectively mined four, five, and seven association rules from the general, embedded, and organic projects data. The consequents of the mined rules suggested two main aspects, namely human capability and product scale, to be particularly concerned in this study. [Conclusions:] The negative correlation between complexity and effort is not a coincidence under particular conditions. In a software project, interactions between product complexity and other factors, such as Programmer Capability and Analyst Capability, can inevitably play a "friction" role in weakening the practical influences of product complexity on actual development effort.
no_new_dataset
0.942823
1509.08439
Sanath Narayan
Sanath Narayan, Kalpathi R. Ramakrishnan
Hyper-Fisher Vectors for Action Recognition
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, a novel encoding scheme combining Fisher vector and bag-of-words encodings has been proposed for recognizing action in videos. The proposed Hyper-Fisher vector encoding is sum of local Fisher vectors which are computed based on the traditional Bag-of-Words (BoW) encoding. Thus, the proposed encoding is simple and yet an effective representation over the traditional Fisher Vector encoding. By extensive evaluation on challenging action recognition datasets, viz., Youtube, Olympic Sports, UCF50 and HMDB51, we show that the proposed Hyper-Fisher Vector encoding improves the recognition performance by around 2-3% compared to the improved Fisher Vector encoding. We also perform experiments to show that the performance of the Hyper-Fisher Vector is robust to the dictionary size of the BoW encoding.
[ { "version": "v1", "created": "Mon, 28 Sep 2015 19:25:34 GMT" } ]
2015-09-29T00:00:00
[ [ "Narayan", "Sanath", "" ], [ "Ramakrishnan", "Kalpathi R.", "" ] ]
TITLE: Hyper-Fisher Vectors for Action Recognition ABSTRACT: In this paper, a novel encoding scheme combining Fisher vector and bag-of-words encodings has been proposed for recognizing action in videos. The proposed Hyper-Fisher vector encoding is sum of local Fisher vectors which are computed based on the traditional Bag-of-Words (BoW) encoding. Thus, the proposed encoding is simple and yet an effective representation over the traditional Fisher Vector encoding. By extensive evaluation on challenging action recognition datasets, viz., Youtube, Olympic Sports, UCF50 and HMDB51, we show that the proposed Hyper-Fisher Vector encoding improves the recognition performance by around 2-3% compared to the improved Fisher Vector encoding. We also perform experiments to show that the performance of the Hyper-Fisher Vector is robust to the dictionary size of the BoW encoding.
no_new_dataset
0.95388
1503.03429
Dat Tien Ngo
Dat Tien Ngo, Sanghuyk Park, Anne Jorstad, Alberto Crivellaro, Chang Yoo, Pascal Fua
Dense image registration and deformable surface reconstruction in presence of occlusions and minimal texture
In Proceedings of International Conference on Computer Vision, 2015
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deformable surface tracking from monocular images is well-known to be under-constrained. Occlusions often make the task even more challenging, and can result in failure if the surface is not sufficiently textured. In this work, we explicitly address the problem of 3D reconstruction of poorly textured, occluded surfaces, proposing a framework based on a template-matching approach that scales dense robust features by a relevancy score. Our approach is extensively compared to current methods employing both local feature matching and dense template alignment. We test on standard datasets as well as on a new dataset (that will be made publicly available) of a sparsely textured, occluded surface. Our framework achieves state-of-the-art results for both well and poorly textured, occluded surfaces.
[ { "version": "v1", "created": "Wed, 11 Mar 2015 17:37:22 GMT" }, { "version": "v2", "created": "Fri, 18 Sep 2015 10:30:02 GMT" }, { "version": "v3", "created": "Fri, 25 Sep 2015 09:07:09 GMT" } ]
2015-09-28T00:00:00
[ [ "Ngo", "Dat Tien", "" ], [ "Park", "Sanghuyk", "" ], [ "Jorstad", "Anne", "" ], [ "Crivellaro", "Alberto", "" ], [ "Yoo", "Chang", "" ], [ "Fua", "Pascal", "" ] ]
TITLE: Dense image registration and deformable surface reconstruction in presence of occlusions and minimal texture ABSTRACT: Deformable surface tracking from monocular images is well-known to be under-constrained. Occlusions often make the task even more challenging, and can result in failure if the surface is not sufficiently textured. In this work, we explicitly address the problem of 3D reconstruction of poorly textured, occluded surfaces, proposing a framework based on a template-matching approach that scales dense robust features by a relevancy score. Our approach is extensively compared to current methods employing both local feature matching and dense template alignment. We test on standard datasets as well as on a new dataset (that will be made publicly available) of a sparsely textured, occluded surface. Our framework achieves state-of-the-art results for both well and poorly textured, occluded surfaces.
new_dataset
0.957833
1506.00511
Jimmy Ba
Jimmy Ba, Kevin Swersky, Sanja Fidler and Ruslan Salakhutdinov
Predicting Deep Zero-Shot Convolutional Neural Networks using Textual Descriptions
Correct the typos in table 1 regarding [5]. To appear in ICCV 2015
null
null
null
cs.LG cs.CV cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
One of the main challenges in Zero-Shot Learning of visual categories is gathering semantic attributes to accompany images. Recent work has shown that learning from textual descriptions, such as Wikipedia articles, avoids the problem of having to explicitly define these attributes. We present a new model that can classify unseen categories from their textual description. Specifically, we use text features to predict the output weights of both the convolutional and the fully connected layers in a deep convolutional neural network (CNN). We take advantage of the architecture of CNNs and learn features at different layers, rather than just learning an embedding space for both modalities, as is common with existing approaches. The proposed model also allows us to automatically generate a list of pseudo- attributes for each visual category consisting of words from Wikipedia articles. We train our models end-to-end us- ing the Caltech-UCSD bird and flower datasets and evaluate both ROC and Precision-Recall curves. Our empirical results show that the proposed model significantly outperforms previous methods.
[ { "version": "v1", "created": "Mon, 1 Jun 2015 14:37:06 GMT" }, { "version": "v2", "created": "Fri, 25 Sep 2015 16:20:44 GMT" } ]
2015-09-28T00:00:00
[ [ "Ba", "Jimmy", "" ], [ "Swersky", "Kevin", "" ], [ "Fidler", "Sanja", "" ], [ "Salakhutdinov", "Ruslan", "" ] ]
TITLE: Predicting Deep Zero-Shot Convolutional Neural Networks using Textual Descriptions ABSTRACT: One of the main challenges in Zero-Shot Learning of visual categories is gathering semantic attributes to accompany images. Recent work has shown that learning from textual descriptions, such as Wikipedia articles, avoids the problem of having to explicitly define these attributes. We present a new model that can classify unseen categories from their textual description. Specifically, we use text features to predict the output weights of both the convolutional and the fully connected layers in a deep convolutional neural network (CNN). We take advantage of the architecture of CNNs and learn features at different layers, rather than just learning an embedding space for both modalities, as is common with existing approaches. The proposed model also allows us to automatically generate a list of pseudo- attributes for each visual category consisting of words from Wikipedia articles. We train our models end-to-end us- ing the Caltech-UCSD bird and flower datasets and evaluate both ROC and Precision-Recall curves. Our empirical results show that the proposed model significantly outperforms previous methods.
no_new_dataset
0.949482
1506.02629
Vitaly Feldman
Cynthia Dwork, Vitaly Feldman, Moritz Hardt, Toniann Pitassi, Omer Reingold, Aaron Roth
Generalization in Adaptive Data Analysis and Holdout Reuse
null
null
null
null
cs.LG cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Overfitting is the bane of data analysts, even when data are plentiful. Formal approaches to understanding this problem focus on statistical inference and generalization of individual analysis procedures. Yet the practice of data analysis is an inherently interactive and adaptive process: new analyses and hypotheses are proposed after seeing the results of previous ones, parameters are tuned on the basis of obtained results, and datasets are shared and reused. An investigation of this gap has recently been initiated by the authors in (Dwork et al., 2014), where we focused on the problem of estimating expectations of adaptively chosen functions. In this paper, we give a simple and practical method for reusing a holdout (or testing) set to validate the accuracy of hypotheses produced by a learning algorithm operating on a training set. Reusing a holdout set adaptively multiple times can easily lead to overfitting to the holdout set itself. We give an algorithm that enables the validation of a large number of adaptively chosen hypotheses, while provably avoiding overfitting. We illustrate the advantages of our algorithm over the standard use of the holdout set via a simple synthetic experiment. We also formalize and address the general problem of data reuse in adaptive data analysis. We show how the differential-privacy based approach given in (Dwork et al., 2014) is applicable much more broadly to adaptive data analysis. We then show that a simple approach based on description length can also be used to give guarantees of statistical validity in adaptive settings. Finally, we demonstrate that these incomparable approaches can be unified via the notion of approximate max-information that we introduce.
[ { "version": "v1", "created": "Mon, 8 Jun 2015 19:34:29 GMT" }, { "version": "v2", "created": "Fri, 25 Sep 2015 19:04:32 GMT" } ]
2015-09-28T00:00:00
[ [ "Dwork", "Cynthia", "" ], [ "Feldman", "Vitaly", "" ], [ "Hardt", "Moritz", "" ], [ "Pitassi", "Toniann", "" ], [ "Reingold", "Omer", "" ], [ "Roth", "Aaron", "" ] ]
TITLE: Generalization in Adaptive Data Analysis and Holdout Reuse ABSTRACT: Overfitting is the bane of data analysts, even when data are plentiful. Formal approaches to understanding this problem focus on statistical inference and generalization of individual analysis procedures. Yet the practice of data analysis is an inherently interactive and adaptive process: new analyses and hypotheses are proposed after seeing the results of previous ones, parameters are tuned on the basis of obtained results, and datasets are shared and reused. An investigation of this gap has recently been initiated by the authors in (Dwork et al., 2014), where we focused on the problem of estimating expectations of adaptively chosen functions. In this paper, we give a simple and practical method for reusing a holdout (or testing) set to validate the accuracy of hypotheses produced by a learning algorithm operating on a training set. Reusing a holdout set adaptively multiple times can easily lead to overfitting to the holdout set itself. We give an algorithm that enables the validation of a large number of adaptively chosen hypotheses, while provably avoiding overfitting. We illustrate the advantages of our algorithm over the standard use of the holdout set via a simple synthetic experiment. We also formalize and address the general problem of data reuse in adaptive data analysis. We show how the differential-privacy based approach given in (Dwork et al., 2014) is applicable much more broadly to adaptive data analysis. We then show that a simple approach based on description length can also be used to give guarantees of statistical validity in adaptive settings. Finally, we demonstrate that these incomparable approaches can be unified via the notion of approximate max-information that we introduce.
no_new_dataset
0.949856
1509.03502
Seong Joon Oh
Seong Joon Oh, Rodrigo Benenson, Mario Fritz, Bernt Schiele
Person Recognition in Personal Photo Collections
Accepted to ICCV 2015, revised
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recognising persons in everyday photos presents major challenges (occluded faces, different clothing, locations, etc.) for machine vision. We propose a convnet based person recognition system on which we provide an in-depth analysis of informativeness of different body cues, impact of training data, and the common failure modes of the system. In addition, we discuss the limitations of existing benchmarks and propose more challenging ones. Our method is simple and is built on open source and open data, yet it improves the state of the art results on a large dataset of social media photos (PIPA).
[ { "version": "v1", "created": "Fri, 11 Sep 2015 13:34:45 GMT" }, { "version": "v2", "created": "Fri, 25 Sep 2015 19:58:34 GMT" } ]
2015-09-28T00:00:00
[ [ "Oh", "Seong Joon", "" ], [ "Benenson", "Rodrigo", "" ], [ "Fritz", "Mario", "" ], [ "Schiele", "Bernt", "" ] ]
TITLE: Person Recognition in Personal Photo Collections ABSTRACT: Recognising persons in everyday photos presents major challenges (occluded faces, different clothing, locations, etc.) for machine vision. We propose a convnet based person recognition system on which we provide an in-depth analysis of informativeness of different body cues, impact of training data, and the common failure modes of the system. In addition, we discuss the limitations of existing benchmarks and propose more challenging ones. Our method is simple and is built on open source and open data, yet it improves the state of the art results on a large dataset of social media photos (PIPA).
no_new_dataset
0.950273
1509.07612
Nils Haldenwang
Nils Haldenwang and Oliver Vornberger
Sentiment Uncertainty and Spam in Twitter Streams and Its Implications for General Purpose Realtime Sentiment Analysis
3 pages, 1 figure, accepted at GSCL '15
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
State of the art benchmarks for Twitter Sentiment Analysis do not consider the fact that for more than half of the tweets from the public stream a distinct sentiment cannot be chosen. This paper provides a new perspective on Twitter Sentiment Analysis by highlighting the necessity of explicitly incorporating uncertainty. Moreover, a dataset of high quality to evaluate solutions for this new problem is introduced and made publicly available.
[ { "version": "v1", "created": "Fri, 25 Sep 2015 07:55:26 GMT" } ]
2015-09-28T00:00:00
[ [ "Haldenwang", "Nils", "" ], [ "Vornberger", "Oliver", "" ] ]
TITLE: Sentiment Uncertainty and Spam in Twitter Streams and Its Implications for General Purpose Realtime Sentiment Analysis ABSTRACT: State of the art benchmarks for Twitter Sentiment Analysis do not consider the fact that for more than half of the tweets from the public stream a distinct sentiment cannot be chosen. This paper provides a new perspective on Twitter Sentiment Analysis by highlighting the necessity of explicitly incorporating uncertainty. Moreover, a dataset of high quality to evaluate solutions for this new problem is introduced and made publicly available.
new_dataset
0.955152
1509.07615
Kanji Tanaka
Enfu Liu, Kanji Tanaka
Discriminative Map Retrieval Using View-Dependent Map Descriptor
Technical Report, 8 pages, 9 figures
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Map retrieval, the problem of similarity search over a large collection of 2D pointset maps previously built by mobile robots, is crucial for autonomous navigation in indoor and outdoor environments. Bag-of-words (BoW) methods constitute a popular approach to map retrieval; however, these methods have extremely limited descriptive ability because they ignore the spatial layout information of the local features. The main contribution of this paper is an extension of the bag-of-words map retrieval method to enable the use of spatial information from local features. Our strategy is to explicitly model a unique viewpoint of an input local map; the pose of the local feature is defined with respect to this unique viewpoint, and can be viewed as an additional invariant feature for discriminative map retrieval. Specifically, we wish to determine a unique viewpoint that is invariant to moving objects, clutter, occlusions, and actual viewpoints. Hence, we perform scene parsing to analyze the scene structure, and consider the "center" of the scene structure to be the unique viewpoint. Our scene parsing is based on a Manhattan world grammar that imposes a quasi-Manhattan world constraint to enable the robust detection of a scene structure that is invariant to clutter and moving objects. Experimental results using the publicly available radish dataset validate the efficacy of the proposed approach.
[ { "version": "v1", "created": "Fri, 25 Sep 2015 08:02:19 GMT" } ]
2015-09-28T00:00:00
[ [ "Liu", "Enfu", "" ], [ "Tanaka", "Kanji", "" ] ]
TITLE: Discriminative Map Retrieval Using View-Dependent Map Descriptor ABSTRACT: Map retrieval, the problem of similarity search over a large collection of 2D pointset maps previously built by mobile robots, is crucial for autonomous navigation in indoor and outdoor environments. Bag-of-words (BoW) methods constitute a popular approach to map retrieval; however, these methods have extremely limited descriptive ability because they ignore the spatial layout information of the local features. The main contribution of this paper is an extension of the bag-of-words map retrieval method to enable the use of spatial information from local features. Our strategy is to explicitly model a unique viewpoint of an input local map; the pose of the local feature is defined with respect to this unique viewpoint, and can be viewed as an additional invariant feature for discriminative map retrieval. Specifically, we wish to determine a unique viewpoint that is invariant to moving objects, clutter, occlusions, and actual viewpoints. Hence, we perform scene parsing to analyze the scene structure, and consider the "center" of the scene structure to be the unique viewpoint. Our scene parsing is based on a Manhattan world grammar that imposes a quasi-Manhattan world constraint to enable the robust detection of a scene structure that is invariant to clutter and moving objects. Experimental results using the publicly available radish dataset validate the efficacy of the proposed approach.
no_new_dataset
0.949809
1509.07618
Kanji Tanaka
Taisho Tsukamoto, Kanji Tanaka
Self-localization Using Visual Experience Across Domains
Technical Report, 8 pages, 8 figures
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this study, we aim to solve the single-view robot self-localization problem by using visual experience across domains. Although the bag-of-words method constitutes a popular approach to single-view localization, it fails badly when it's visual vocabulary is learned and tested in different domains. Further, we are interested in using a cross-domain setting, in which the visual vocabulary is learned in different seasons and routes from the input query/database scenes. Our strategy is to mine a cross-domain visual experience, a library of raw visual images collected in different domains, to discover the relevant visual patterns that effectively explain the input scene, and use them for scene retrieval. In particular, we show that the appearance and the pose of the mined visual patterns of a query scene can be efficiently and discriminatively matched against those of the database scenes by employing image-to-class distance and spatial pyramid matching. Experimental results obtained using a novel cross-domain dataset show that our system achieves promising results despite our visual vocabulary being learned and tested in different domains.
[ { "version": "v1", "created": "Fri, 25 Sep 2015 08:07:10 GMT" } ]
2015-09-28T00:00:00
[ [ "Tsukamoto", "Taisho", "" ], [ "Tanaka", "Kanji", "" ] ]
TITLE: Self-localization Using Visual Experience Across Domains ABSTRACT: In this study, we aim to solve the single-view robot self-localization problem by using visual experience across domains. Although the bag-of-words method constitutes a popular approach to single-view localization, it fails badly when it's visual vocabulary is learned and tested in different domains. Further, we are interested in using a cross-domain setting, in which the visual vocabulary is learned in different seasons and routes from the input query/database scenes. Our strategy is to mine a cross-domain visual experience, a library of raw visual images collected in different domains, to discover the relevant visual patterns that effectively explain the input scene, and use them for scene retrieval. In particular, we show that the appearance and the pose of the mined visual patterns of a query scene can be efficiently and discriminatively matched against those of the database scenes by employing image-to-class distance and spatial pyramid matching. Experimental results obtained using a novel cross-domain dataset show that our system achieves promising results despite our visual vocabulary being learned and tested in different domains.
new_dataset
0.956594
1509.07627
Hirokatsu Kataoka
Hirokatsu Kataoka, Kenji Iwata, Yutaka Satoh
Feature Evaluation of Deep Convolutional Neural Networks for Object Recognition and Detection
5 pages, 3 figures
null
null
null
cs.CV cs.AI cs.MM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we evaluate convolutional neural network (CNN) features using the AlexNet architecture and very deep convolutional network (VGGNet) architecture. To date, most CNN researchers have employed the last layers before output, which were extracted from the fully connected feature layers. However, since it is unlikely that feature representation effectiveness is dependent on the problem, this study evaluates additional convolutional layers that are adjacent to fully connected layers, in addition to executing simple tuning for feature concatenation (e.g., layer 3 + layer 5 + layer 7) and transformation, using tools such as principal component analysis. In our experiments, we carried out detection and classification tasks using the Caltech 101 and Daimler Pedestrian Benchmark Datasets.
[ { "version": "v1", "created": "Fri, 25 Sep 2015 08:26:53 GMT" } ]
2015-09-28T00:00:00
[ [ "Kataoka", "Hirokatsu", "" ], [ "Iwata", "Kenji", "" ], [ "Satoh", "Yutaka", "" ] ]
TITLE: Feature Evaluation of Deep Convolutional Neural Networks for Object Recognition and Detection ABSTRACT: In this paper, we evaluate convolutional neural network (CNN) features using the AlexNet architecture and very deep convolutional network (VGGNet) architecture. To date, most CNN researchers have employed the last layers before output, which were extracted from the fully connected feature layers. However, since it is unlikely that feature representation effectiveness is dependent on the problem, this study evaluates additional convolutional layers that are adjacent to fully connected layers, in addition to executing simple tuning for feature concatenation (e.g., layer 3 + layer 5 + layer 7) and transformation, using tools such as principal component analysis. In our experiments, we carried out detection and classification tasks using the Caltech 101 and Daimler Pedestrian Benchmark Datasets.
no_new_dataset
0.951097
1509.07715
Yixuan Li
Yixuan Li, Kun He, David Bindel and John Hopcroft
Uncovering the Small Community Structure in Large Networks: A Local Spectral Approach
10pages, published in WWW2015 proceedings
null
null
null
cs.SI cs.DS physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Large graphs arise in a number of contexts and understanding their structure and extracting information from them is an important research area. Early algorithms on mining communities have focused on the global structure, and often run in time functional to the size of the entire graph. Nowadays, as we often explore networks with billions of vertices and find communities of size hundreds, it is crucial to shift our attention from macroscopic structure to microscopic structure when dealing with large networks. A growing body of work has been adopting local expansion methods in order to identify the community from a few exemplary seed members. In this paper, we propose a novel approach for finding overlapping communities called LEMON (Local Expansion via Minimum One Norm). Different from PageRank-like diffusion methods, LEMON finds the community by seeking a sparse vector in the span of the local spectra such that the seeds are in its support. We show that LEMON can achieve the highest detection accuracy among state-of-the-art proposals. The running time depends on the size of the community rather than that of the entire graph. The algorithm is easy to implement, and is highly parallelizable. Moreover, given that networks are not all similar in nature, a comprehensive analysis on how the local expansion approach is suited for uncovering communities in different networks is still lacking. We thoroughly evaluate our approach using both synthetic and real-world datasets across different domains, and analyze the empirical variations when applying our method to inherently different networks in practice. In addition, the heuristics on how the quality and quantity of the seed set would affect the performance are provided.
[ { "version": "v1", "created": "Fri, 25 Sep 2015 13:50:34 GMT" } ]
2015-09-28T00:00:00
[ [ "Li", "Yixuan", "" ], [ "He", "Kun", "" ], [ "Bindel", "David", "" ], [ "Hopcroft", "John", "" ] ]
TITLE: Uncovering the Small Community Structure in Large Networks: A Local Spectral Approach ABSTRACT: Large graphs arise in a number of contexts and understanding their structure and extracting information from them is an important research area. Early algorithms on mining communities have focused on the global structure, and often run in time functional to the size of the entire graph. Nowadays, as we often explore networks with billions of vertices and find communities of size hundreds, it is crucial to shift our attention from macroscopic structure to microscopic structure when dealing with large networks. A growing body of work has been adopting local expansion methods in order to identify the community from a few exemplary seed members. In this paper, we propose a novel approach for finding overlapping communities called LEMON (Local Expansion via Minimum One Norm). Different from PageRank-like diffusion methods, LEMON finds the community by seeking a sparse vector in the span of the local spectra such that the seeds are in its support. We show that LEMON can achieve the highest detection accuracy among state-of-the-art proposals. The running time depends on the size of the community rather than that of the entire graph. The algorithm is easy to implement, and is highly parallelizable. Moreover, given that networks are not all similar in nature, a comprehensive analysis on how the local expansion approach is suited for uncovering communities in different networks is still lacking. We thoroughly evaluate our approach using both synthetic and real-world datasets across different domains, and analyze the empirical variations when applying our method to inherently different networks in practice. In addition, the heuristics on how the quality and quantity of the seed set would affect the performance are provided.
no_new_dataset
0.945551
1509.07823
Pablo Huijse Ph.D
Pablo Huijse and Pablo A. Estevez and Pavlos Protopapas and Jose C. Principe and Pablo Zegers
Computational Intelligence Challenges and Applications on Large-Scale Astronomical Time Series Databases
null
IEEE Computational Intelligence Magazine, vol. 9, n. 3, pp. 27-39, 2014
10.1109/MCI.2014.2326100
null
astro-ph.IM cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Time-domain astronomy (TDA) is facing a paradigm shift caused by the exponential growth of the sample size, data complexity and data generation rates of new astronomical sky surveys. For example, the Large Synoptic Survey Telescope (LSST), which will begin operations in northern Chile in 2022, will generate a nearly 150 Petabyte imaging dataset of the southern hemisphere sky. The LSST will stream data at rates of 2 Terabytes per hour, effectively capturing an unprecedented movie of the sky. The LSST is expected not only to improve our understanding of time-varying astrophysical objects, but also to reveal a plethora of yet unknown faint and fast-varying phenomena. To cope with a change of paradigm to data-driven astronomy, the fields of astroinformatics and astrostatistics have been created recently. The new data-oriented paradigms for astronomy combine statistics, data mining, knowledge discovery, machine learning and computational intelligence, in order to provide the automated and robust methods needed for the rapid detection and classification of known astrophysical objects as well as the unsupervised characterization of novel phenomena. In this article we present an overview of machine learning and computational intelligence applications to TDA. Future big data challenges and new lines of research in TDA, focusing on the LSST, are identified and discussed from the viewpoint of computational intelligence/machine learning. Interdisciplinary collaboration will be required to cope with the challenges posed by the deluge of astronomical data coming from the LSST.
[ { "version": "v1", "created": "Fri, 25 Sep 2015 18:24:48 GMT" } ]
2015-09-28T00:00:00
[ [ "Huijse", "Pablo", "" ], [ "Estevez", "Pablo A.", "" ], [ "Protopapas", "Pavlos", "" ], [ "Principe", "Jose C.", "" ], [ "Zegers", "Pablo", "" ] ]
TITLE: Computational Intelligence Challenges and Applications on Large-Scale Astronomical Time Series Databases ABSTRACT: Time-domain astronomy (TDA) is facing a paradigm shift caused by the exponential growth of the sample size, data complexity and data generation rates of new astronomical sky surveys. For example, the Large Synoptic Survey Telescope (LSST), which will begin operations in northern Chile in 2022, will generate a nearly 150 Petabyte imaging dataset of the southern hemisphere sky. The LSST will stream data at rates of 2 Terabytes per hour, effectively capturing an unprecedented movie of the sky. The LSST is expected not only to improve our understanding of time-varying astrophysical objects, but also to reveal a plethora of yet unknown faint and fast-varying phenomena. To cope with a change of paradigm to data-driven astronomy, the fields of astroinformatics and astrostatistics have been created recently. The new data-oriented paradigms for astronomy combine statistics, data mining, knowledge discovery, machine learning and computational intelligence, in order to provide the automated and robust methods needed for the rapid detection and classification of known astrophysical objects as well as the unsupervised characterization of novel phenomena. In this article we present an overview of machine learning and computational intelligence applications to TDA. Future big data challenges and new lines of research in TDA, focusing on the LSST, are identified and discussed from the viewpoint of computational intelligence/machine learning. Interdisciplinary collaboration will be required to cope with the challenges posed by the deluge of astronomical data coming from the LSST.
no_new_dataset
0.922062
1509.07845
Xintong Han
Bharat Singh, Xintong Han, Zhe Wu, Vlad I. Morariu and Larry S. Davis
Selecting Relevant Web Trained Concepts for Automated Event Retrieval
null
null
null
null
cs.CV cs.CL cs.IR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Complex event retrieval is a challenging research problem, especially when no training videos are available. An alternative to collecting training videos is to train a large semantic concept bank a priori. Given a text description of an event, event retrieval is performed by selecting concepts linguistically related to the event description and fusing the concept responses on unseen videos. However, defining an exhaustive concept lexicon and pre-training it requires vast computational resources. Therefore, recent approaches automate concept discovery and training by leveraging large amounts of weakly annotated web data. Compact visually salient concepts are automatically obtained by the use of concept pairs or, more generally, n-grams. However, not all visually salient n-grams are necessarily useful for an event query--some combinations of concepts may be visually compact but irrelevant--and this drastically affects performance. We propose an event retrieval algorithm that constructs pairs of automatically discovered concepts and then prunes those concepts that are unlikely to be helpful for retrieval. Pruning depends both on the query and on the specific video instance being evaluated. Our approach also addresses calibration and domain adaptation issues that arise when applying concept detectors to unseen videos. We demonstrate large improvements over other vision based systems on the TRECVID MED 13 dataset.
[ { "version": "v1", "created": "Fri, 25 Sep 2015 19:27:54 GMT" } ]
2015-09-28T00:00:00
[ [ "Singh", "Bharat", "" ], [ "Han", "Xintong", "" ], [ "Wu", "Zhe", "" ], [ "Morariu", "Vlad I.", "" ], [ "Davis", "Larry S.", "" ] ]
TITLE: Selecting Relevant Web Trained Concepts for Automated Event Retrieval ABSTRACT: Complex event retrieval is a challenging research problem, especially when no training videos are available. An alternative to collecting training videos is to train a large semantic concept bank a priori. Given a text description of an event, event retrieval is performed by selecting concepts linguistically related to the event description and fusing the concept responses on unseen videos. However, defining an exhaustive concept lexicon and pre-training it requires vast computational resources. Therefore, recent approaches automate concept discovery and training by leveraging large amounts of weakly annotated web data. Compact visually salient concepts are automatically obtained by the use of concept pairs or, more generally, n-grams. However, not all visually salient n-grams are necessarily useful for an event query--some combinations of concepts may be visually compact but irrelevant--and this drastically affects performance. We propose an event retrieval algorithm that constructs pairs of automatically discovered concepts and then prunes those concepts that are unlikely to be helpful for retrieval. Pruning depends both on the query and on the specific video instance being evaluated. Our approach also addresses calibration and domain adaptation issues that arise when applying concept detectors to unseen videos. We demonstrate large improvements over other vision based systems on the TRECVID MED 13 dataset.
no_new_dataset
0.949576
1411.4423
Sotirios Chatzis
Sotirios P. Chatzis
A Nonparametric Bayesian Approach Toward Stacked Convolutional Independent Component Analysis
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Unsupervised feature learning algorithms based on convolutional formulations of independent components analysis (ICA) have been demonstrated to yield state-of-the-art results in several action recognition benchmarks. However, existing approaches do not allow for the number of latent components (features) to be automatically inferred from the data in an unsupervised manner. This is a significant disadvantage of the state-of-the-art, as it results in considerable burden imposed on researchers and practitioners, who must resort to tedious cross-validation procedures to obtain the optimal number of latent features. To resolve these issues, in this paper we introduce a convolutional nonparametric Bayesian sparse ICA architecture for overcomplete feature learning from high-dimensional data. Our method utilizes an Indian buffet process prior to facilitate inference of the appropriate number of latent features under a hybrid variational inference algorithm, scalable to massive datasets. As we show, our model can be naturally used to obtain deep unsupervised hierarchical feature extractors, by greedily stacking successive model layers, similar to existing approaches. In addition, inference for this model is completely heuristics-free; thus, it obviates the need of tedious parameter tuning, which is a major challenge most deep learning approaches are faced with. We evaluate our method on several action recognition benchmarks, and exhibit its advantages over the state-of-the-art.
[ { "version": "v1", "created": "Mon, 17 Nov 2014 10:35:09 GMT" }, { "version": "v2", "created": "Mon, 31 Aug 2015 07:40:21 GMT" }, { "version": "v3", "created": "Tue, 1 Sep 2015 12:03:38 GMT" }, { "version": "v4", "created": "Thu, 3 Sep 2015 10:32:05 GMT" }, { "version": "v5", "created": "Wed, 23 Sep 2015 20:22:53 GMT" } ]
2015-09-25T00:00:00
[ [ "Chatzis", "Sotirios P.", "" ] ]
TITLE: A Nonparametric Bayesian Approach Toward Stacked Convolutional Independent Component Analysis ABSTRACT: Unsupervised feature learning algorithms based on convolutional formulations of independent components analysis (ICA) have been demonstrated to yield state-of-the-art results in several action recognition benchmarks. However, existing approaches do not allow for the number of latent components (features) to be automatically inferred from the data in an unsupervised manner. This is a significant disadvantage of the state-of-the-art, as it results in considerable burden imposed on researchers and practitioners, who must resort to tedious cross-validation procedures to obtain the optimal number of latent features. To resolve these issues, in this paper we introduce a convolutional nonparametric Bayesian sparse ICA architecture for overcomplete feature learning from high-dimensional data. Our method utilizes an Indian buffet process prior to facilitate inference of the appropriate number of latent features under a hybrid variational inference algorithm, scalable to massive datasets. As we show, our model can be naturally used to obtain deep unsupervised hierarchical feature extractors, by greedily stacking successive model layers, similar to existing approaches. In addition, inference for this model is completely heuristics-free; thus, it obviates the need of tedious parameter tuning, which is a major challenge most deep learning approaches are faced with. We evaluate our method on several action recognition benchmarks, and exhibit its advantages over the state-of-the-art.
no_new_dataset
0.945801
1506.08959
Linjie Yang
Linjie Yang, Ping Luo, Chen Change Loy, Xiaoou Tang
A Large-Scale Car Dataset for Fine-Grained Categorization and Verification
An extension to our conference paper in CVPR 2015
null
null
null
cs.CV cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Updated on 24/09/2015: This update provides preliminary experiment results for fine-grained classification on the surveillance data of CompCars. The train/test splits are provided in the updated dataset. See details in Section 6.
[ { "version": "v1", "created": "Tue, 30 Jun 2015 06:47:50 GMT" }, { "version": "v2", "created": "Thu, 24 Sep 2015 09:04:24 GMT" } ]
2015-09-25T00:00:00
[ [ "Yang", "Linjie", "" ], [ "Luo", "Ping", "" ], [ "Loy", "Chen Change", "" ], [ "Tang", "Xiaoou", "" ] ]
TITLE: A Large-Scale Car Dataset for Fine-Grained Categorization and Verification ABSTRACT: Updated on 24/09/2015: This update provides preliminary experiment results for fine-grained classification on the surveillance data of CompCars. The train/test splits are provided in the updated dataset. See details in Section 6.
no_new_dataset
0.71794
1508.02884
Ernesto Diaz-Aviles
Ernesto Diaz-Aviles (1), Fabio Pinelli (1), Karol Lynch (1), Zubair Nabi (1), Yiannis Gkoufas (1), Eric Bouillet (1), Francesco Calabrese (1), Eoin Coughlan (2), Peter Holland (2), Jason Salzwedel (2) ((1) IBM Research -- Ireland, (2) IBM Now Factory -- Ireland, (3) Vodacom -- South Africa)
Towards Real-time Customer Experience Prediction for Telecommunication Operators
IEEE 2015 BigData Conference (to appear). Keywords: Telecom operators; Customer Care; Big Data; Predictive Analytics
null
null
null
cs.CY cs.IR stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Telecommunications operators (telcos) traditional sources of income, voice and SMS, are shrinking due to customers using over-the-top (OTT) applications such as WhatsApp or Viber. In this challenging environment it is critical for telcos to maintain or grow their market share, by providing users with as good an experience as possible on their network. But the task of extracting customer insights from the vast amounts of data collected by telcos is growing in complexity and scale everey day. How can we measure and predict the quality of a user's experience on a telco network in real-time? That is the problem that we address in this paper. We present an approach to capture, in (near) real-time, the mobile customer experience in order to assess which conditions lead the user to place a call to a telco's customer care center. To this end, we follow a supervised learning approach for prediction and train our 'Restricted Random Forest' model using, as a proxy for bad experience, the observed customer transactions in the telco data feed before the user places a call to a customer care center. We evaluate our approach using a rich dataset provided by a major African telecommunication's company and a novel big data architecture for both the training and scoring of predictive models. Our empirical study shows our solution to be effective at predicting user experience by inferring if a customer will place a call based on his current context. These promising results open new possibilities for improved customer service, which will help telcos to reduce churn rates and improve customer experience, both factors that directly impact their revenue growth.
[ { "version": "v1", "created": "Wed, 12 Aug 2015 11:43:11 GMT" }, { "version": "v2", "created": "Thu, 24 Sep 2015 15:26:48 GMT" } ]
2015-09-25T00:00:00
[ [ "Diaz-Aviles", "Ernesto", "" ], [ "Pinelli", "Fabio", "" ], [ "Lynch", "Karol", "" ], [ "Nabi", "Zubair", "" ], [ "Gkoufas", "Yiannis", "" ], [ "Bouillet", "Eric", "" ], [ "Calabrese", "Francesco", "" ], [ "Coughlan", "Eoin", "" ], [ "Holland", "Peter", "" ], [ "Salzwedel", "Jason", "" ] ]
TITLE: Towards Real-time Customer Experience Prediction for Telecommunication Operators ABSTRACT: Telecommunications operators (telcos) traditional sources of income, voice and SMS, are shrinking due to customers using over-the-top (OTT) applications such as WhatsApp or Viber. In this challenging environment it is critical for telcos to maintain or grow their market share, by providing users with as good an experience as possible on their network. But the task of extracting customer insights from the vast amounts of data collected by telcos is growing in complexity and scale everey day. How can we measure and predict the quality of a user's experience on a telco network in real-time? That is the problem that we address in this paper. We present an approach to capture, in (near) real-time, the mobile customer experience in order to assess which conditions lead the user to place a call to a telco's customer care center. To this end, we follow a supervised learning approach for prediction and train our 'Restricted Random Forest' model using, as a proxy for bad experience, the observed customer transactions in the telco data feed before the user places a call to a customer care center. We evaluate our approach using a rich dataset provided by a major African telecommunication's company and a novel big data architecture for both the training and scoring of predictive models. Our empirical study shows our solution to be effective at predicting user experience by inferring if a customer will place a call based on his current context. These promising results open new possibilities for improved customer service, which will help telcos to reduce churn rates and improve customer experience, both factors that directly impact their revenue growth.
no_new_dataset
0.941708
1509.02634
Ziwei Liu
Ziwei Liu, Xiaoxiao Li, Ping Luo, Chen Change Loy, Xiaoou Tang
Semantic Image Segmentation via Deep Parsing Network
To appear in International Conference on Computer Vision (ICCV) 2015
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper addresses semantic image segmentation by incorporating rich information into Markov Random Field (MRF), including high-order relations and mixture of label contexts. Unlike previous works that optimized MRFs using iterative algorithm, we solve MRF by proposing a Convolutional Neural Network (CNN), namely Deep Parsing Network (DPN), which enables deterministic end-to-end computation in a single forward pass. Specifically, DPN extends a contemporary CNN architecture to model unary terms and additional layers are carefully devised to approximate the mean field algorithm (MF) for pairwise terms. It has several appealing properties. First, different from the recent works that combined CNN and MRF, where many iterations of MF were required for each training image during back-propagation, DPN is able to achieve high performance by approximating one iteration of MF. Second, DPN represents various types of pairwise terms, making many existing works as its special cases. Third, DPN makes MF easier to be parallelized and speeded up in Graphical Processing Unit (GPU). DPN is thoroughly evaluated on the PASCAL VOC 2012 dataset, where a single DPN model yields a new state-of-the-art segmentation accuracy.
[ { "version": "v1", "created": "Wed, 9 Sep 2015 04:39:34 GMT" }, { "version": "v2", "created": "Thu, 24 Sep 2015 14:15:17 GMT" } ]
2015-09-25T00:00:00
[ [ "Liu", "Ziwei", "" ], [ "Li", "Xiaoxiao", "" ], [ "Luo", "Ping", "" ], [ "Loy", "Chen Change", "" ], [ "Tang", "Xiaoou", "" ] ]
TITLE: Semantic Image Segmentation via Deep Parsing Network ABSTRACT: This paper addresses semantic image segmentation by incorporating rich information into Markov Random Field (MRF), including high-order relations and mixture of label contexts. Unlike previous works that optimized MRFs using iterative algorithm, we solve MRF by proposing a Convolutional Neural Network (CNN), namely Deep Parsing Network (DPN), which enables deterministic end-to-end computation in a single forward pass. Specifically, DPN extends a contemporary CNN architecture to model unary terms and additional layers are carefully devised to approximate the mean field algorithm (MF) for pairwise terms. It has several appealing properties. First, different from the recent works that combined CNN and MRF, where many iterations of MF were required for each training image during back-propagation, DPN is able to achieve high performance by approximating one iteration of MF. Second, DPN represents various types of pairwise terms, making many existing works as its special cases. Third, DPN makes MF easier to be parallelized and speeded up in Graphical Processing Unit (GPU). DPN is thoroughly evaluated on the PASCAL VOC 2012 dataset, where a single DPN model yields a new state-of-the-art segmentation accuracy.
no_new_dataset
0.949763
1509.07211
Fengyun Zhu
Zaihu Pang, Fengyun Zhu
Noise-Robust ASR for the third 'CHiME' Challenge Exploiting Time-Frequency Masking based Multi-Channel Speech Enhancement and Recurrent Neural Network
The 3rd 'CHiME' Speech Separation and Recognition Challenge, 5 pages, 1 figure
null
null
null
cs.SD cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, the Lingban entry to the third 'CHiME' speech separation and recognition challenge is presented. A time-frequency masking based speech enhancement front-end is proposed to suppress the environmental noise utilizing multi-channel coherence and spatial cues. The state-of-the-art speech recognition techniques, namely recurrent neural network based acoustic and language modeling, state space minimum Bayes risk based discriminative acoustic modeling, and i-vector based acoustic condition modeling, are carefully integrated into the speech recognition back-end. To further improve the system performance by fully exploiting the advantages of different technologies, the final recognition results are obtained by lattice combination and rescoring. Evaluations carried out on the official dataset prove the effectiveness of the proposed systems. Comparing with the best baseline result, the proposed system obtains consistent improvements with over 57% relative word error rate reduction on the real-data test set.
[ { "version": "v1", "created": "Thu, 24 Sep 2015 02:16:11 GMT" } ]
2015-09-25T00:00:00
[ [ "Pang", "Zaihu", "" ], [ "Zhu", "Fengyun", "" ] ]
TITLE: Noise-Robust ASR for the third 'CHiME' Challenge Exploiting Time-Frequency Masking based Multi-Channel Speech Enhancement and Recurrent Neural Network ABSTRACT: In this paper, the Lingban entry to the third 'CHiME' speech separation and recognition challenge is presented. A time-frequency masking based speech enhancement front-end is proposed to suppress the environmental noise utilizing multi-channel coherence and spatial cues. The state-of-the-art speech recognition techniques, namely recurrent neural network based acoustic and language modeling, state space minimum Bayes risk based discriminative acoustic modeling, and i-vector based acoustic condition modeling, are carefully integrated into the speech recognition back-end. To further improve the system performance by fully exploiting the advantages of different technologies, the final recognition results are obtained by lattice combination and rescoring. Evaluations carried out on the official dataset prove the effectiveness of the proposed systems. Comparing with the best baseline result, the proposed system obtains consistent improvements with over 57% relative word error rate reduction on the real-data test set.
no_new_dataset
0.94625
1509.07454
Sanjay Krishnan
Sanjay Krishnan, Jiannan Wang, Michael J. Franklin, Ken Goldberg, Tim Kraska
Stale View Cleaning: Getting Fresh Answers from Stale Materialized Views
null
Proceedings of the VLDB Endowment - Proceedings of the 41st International Conference on Very Large Data Bases, Kohala Coast, Hawaii Volume 8 Issue 12, August 2015 Pages 1370-1381
10.14778/2824032.2824037
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Materialized views (MVs), stored pre-computed results, are widely used to facilitate fast queries on large datasets. When new records arrive at a high rate, it is infeasible to continuously update (maintain) MVs and a common solution is to defer maintenance by batching updates together. Between batches the MVs become increasingly stale with incorrect, missing, and superfluous rows leading to increasingly inaccurate query results. We propose Stale View Cleaning (SVC) which addresses this problem from a data cleaning perspective. In SVC, we efficiently clean a sample of rows from a stale MV, and use the clean sample to estimate aggregate query results. While approximate, the estimated query results reflect the most recent data. As sampling can be sensitive to long-tailed distributions, we further explore an outlier indexing technique to give increased accuracy when the data distributions are skewed. SVC complements existing deferred maintenance approaches by giving accurate and bounded query answers between maintenance. We evaluate our method on a generated dataset from the TPC-D benchmark and a real video distribution application. Experiments confirm our theoretical results: (1) cleaning an MV sample is more efficient than full view maintenance, (2) the estimated results are more accurate than using the stale MV, and (3) SVC is applicable for a wide variety of MVs.
[ { "version": "v1", "created": "Thu, 24 Sep 2015 18:01:33 GMT" } ]
2015-09-25T00:00:00
[ [ "Krishnan", "Sanjay", "" ], [ "Wang", "Jiannan", "" ], [ "Franklin", "Michael J.", "" ], [ "Goldberg", "Ken", "" ], [ "Kraska", "Tim", "" ] ]
TITLE: Stale View Cleaning: Getting Fresh Answers from Stale Materialized Views ABSTRACT: Materialized views (MVs), stored pre-computed results, are widely used to facilitate fast queries on large datasets. When new records arrive at a high rate, it is infeasible to continuously update (maintain) MVs and a common solution is to defer maintenance by batching updates together. Between batches the MVs become increasingly stale with incorrect, missing, and superfluous rows leading to increasingly inaccurate query results. We propose Stale View Cleaning (SVC) which addresses this problem from a data cleaning perspective. In SVC, we efficiently clean a sample of rows from a stale MV, and use the clean sample to estimate aggregate query results. While approximate, the estimated query results reflect the most recent data. As sampling can be sensitive to long-tailed distributions, we further explore an outlier indexing technique to give increased accuracy when the data distributions are skewed. SVC complements existing deferred maintenance approaches by giving accurate and bounded query answers between maintenance. We evaluate our method on a generated dataset from the TPC-D benchmark and a real video distribution application. Experiments confirm our theoretical results: (1) cleaning an MV sample is more efficient than full view maintenance, (2) the estimated results are more accurate than using the stale MV, and (3) SVC is applicable for a wide variety of MVs.
no_new_dataset
0.950411
1509.07481
Zhiguang Wang
Zhiguang Wang and Tim Oates
Spatially Encoding Temporal Correlations to Classify Temporal Data Using Convolutional Neural Networks
Submit to JCSS. Preliminary versions are appeared in AAAI 2015 workshop and IJCAI 2016 [arXiv:1506.00327]
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose an off-line approach to explicitly encode temporal patterns spatially as different types of images, namely, Gramian Angular Fields and Markov Transition Fields. This enables the use of techniques from computer vision for feature learning and classification. We used Tiled Convolutional Neural Networks to learn high-level features from individual GAF, MTF, and GAF-MTF images on 12 benchmark time series datasets and two real spatial-temporal trajectory datasets. The classification results of our approach are competitive with state-of-the-art approaches on both types of data. An analysis of the features and weights learned by the CNNs explains why the approach works.
[ { "version": "v1", "created": "Thu, 24 Sep 2015 19:14:20 GMT" } ]
2015-09-25T00:00:00
[ [ "Wang", "Zhiguang", "" ], [ "Oates", "Tim", "" ] ]
TITLE: Spatially Encoding Temporal Correlations to Classify Temporal Data Using Convolutional Neural Networks ABSTRACT: We propose an off-line approach to explicitly encode temporal patterns spatially as different types of images, namely, Gramian Angular Fields and Markov Transition Fields. This enables the use of techniques from computer vision for feature learning and classification. We used Tiled Convolutional Neural Networks to learn high-level features from individual GAF, MTF, and GAF-MTF images on 12 benchmark time series datasets and two real spatial-temporal trajectory datasets. The classification results of our approach are competitive with state-of-the-art approaches on both types of data. An analysis of the features and weights learned by the CNNs explains why the approach works.
no_new_dataset
0.951142
1412.1840
Pablo Huijse
Pavlos Protopapas and Pablo Huijse and Pablo A. Estevez and Pablo Zegers and Jose C. Principe
A Novel, Fully Automated Pipeline for Period Estimation in the EROS 2 Data Set
null
The Astrophysical Journal Supplement Series, Volume 216, Number 2, 2015
10.1088/0067-0049/216/2/25
null
astro-ph.IM astro-ph.SR cs.IT math.IT
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new method to discriminate periodic from non-periodic irregularly sampled lightcurves. We introduce a periodic kernel and maximize a similarity measure derived from information theory to estimate the periods and a discriminator factor. We tested the method on a dataset containing 100,000 synthetic periodic and non-periodic lightcurves with various periods, amplitudes and shapes generated using a multivariate generative model. We correctly identified periodic and non-periodic lightcurves with a completeness of 90% and a precision of 95%, for lightcurves with a signal-to-noise ratio (SNR) larger than 0.5. We characterize the efficiency and reliability of the model using these synthetic lightcurves and applied the method on the EROS-2 dataset. A crucial consideration is the speed at which the method can be executed. Using hierarchical search and some simplification on the parameter search we were able to analyze 32.8 million lightcurves in 18 hours on a cluster of GPGPUs. Using the sensitivity analysis on the synthetic dataset, we infer that 0.42% in the LMC and 0.61% in the SMC of the sources show periodic behavior. The training set, the catalogs and source code are all available in http://timemachine.iic.harvard.edu.
[ { "version": "v1", "created": "Thu, 4 Dec 2014 21:08:55 GMT" } ]
2015-09-24T00:00:00
[ [ "Protopapas", "Pavlos", "" ], [ "Huijse", "Pablo", "" ], [ "Estevez", "Pablo A.", "" ], [ "Zegers", "Pablo", "" ], [ "Principe", "Jose C.", "" ] ]
TITLE: A Novel, Fully Automated Pipeline for Period Estimation in the EROS 2 Data Set ABSTRACT: We present a new method to discriminate periodic from non-periodic irregularly sampled lightcurves. We introduce a periodic kernel and maximize a similarity measure derived from information theory to estimate the periods and a discriminator factor. We tested the method on a dataset containing 100,000 synthetic periodic and non-periodic lightcurves with various periods, amplitudes and shapes generated using a multivariate generative model. We correctly identified periodic and non-periodic lightcurves with a completeness of 90% and a precision of 95%, for lightcurves with a signal-to-noise ratio (SNR) larger than 0.5. We characterize the efficiency and reliability of the model using these synthetic lightcurves and applied the method on the EROS-2 dataset. A crucial consideration is the speed at which the method can be executed. Using hierarchical search and some simplification on the parameter search we were able to analyze 32.8 million lightcurves in 18 hours on a cluster of GPGPUs. Using the sensitivity analysis on the synthetic dataset, we infer that 0.42% in the LMC and 0.61% in the SMC of the sources show periodic behavior. The training set, the catalogs and source code are all available in http://timemachine.iic.harvard.edu.
no_new_dataset
0.944331
1412.7024
Matthieu Courbariaux
Matthieu Courbariaux, Yoshua Bengio and Jean-Pierre David
Training deep neural networks with low precision multiplications
10 pages, 5 figures, Accepted as a workshop contribution at ICLR 2015
null
null
null
cs.LG cs.CV cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multipliers are the most space and power-hungry arithmetic operators of the digital implementation of deep neural networks. We train a set of state-of-the-art neural networks (Maxout networks) on three benchmark datasets: MNIST, CIFAR-10 and SVHN. They are trained with three distinct formats: floating point, fixed point and dynamic fixed point. For each of those datasets and for each of those formats, we assess the impact of the precision of the multiplications on the final error after training. We find that very low precision is sufficient not just for running trained networks but also for training them. For example, it is possible to train Maxout networks with 10 bits multiplications.
[ { "version": "v1", "created": "Mon, 22 Dec 2014 15:22:45 GMT" }, { "version": "v2", "created": "Thu, 25 Dec 2014 18:05:12 GMT" }, { "version": "v3", "created": "Thu, 26 Feb 2015 00:26:12 GMT" }, { "version": "v4", "created": "Fri, 3 Apr 2015 22:52:43 GMT" }, { "version": "v5", "created": "Wed, 23 Sep 2015 01:00:44 GMT" } ]
2015-09-24T00:00:00
[ [ "Courbariaux", "Matthieu", "" ], [ "Bengio", "Yoshua", "" ], [ "David", "Jean-Pierre", "" ] ]
TITLE: Training deep neural networks with low precision multiplications ABSTRACT: Multipliers are the most space and power-hungry arithmetic operators of the digital implementation of deep neural networks. We train a set of state-of-the-art neural networks (Maxout networks) on three benchmark datasets: MNIST, CIFAR-10 and SVHN. They are trained with three distinct formats: floating point, fixed point and dynamic fixed point. For each of those datasets and for each of those formats, we assess the impact of the precision of the multiplications on the final error after training. We find that very low precision is sufficient not just for running trained networks but also for training them. For example, it is possible to train Maxout networks with 10 bits multiplications.
no_new_dataset
0.950503
1506.03607
Guilhem Ch\'eron
Guilhem Ch\'eron, Ivan Laptev, Cordelia Schmid
P-CNN: Pose-based CNN Features for Action Recognition
ICCV, December 2015, Santiago, Chile
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This work targets human action recognition in video. While recent methods typically represent actions by statistics of local video features, here we argue for the importance of a representation derived from human pose. To this end we propose a new Pose-based Convolutional Neural Network descriptor (P-CNN) for action recognition. The descriptor aggregates motion and appearance information along tracks of human body parts. We investigate different schemes of temporal aggregation and experiment with P-CNN features obtained both for automatically estimated and manually annotated human poses. We evaluate our method on the recent and challenging JHMDB and MPII Cooking datasets. For both datasets our method shows consistent improvement over the state of the art.
[ { "version": "v1", "created": "Thu, 11 Jun 2015 10:02:03 GMT" }, { "version": "v2", "created": "Wed, 23 Sep 2015 10:48:29 GMT" } ]
2015-09-24T00:00:00
[ [ "Chéron", "Guilhem", "" ], [ "Laptev", "Ivan", "" ], [ "Schmid", "Cordelia", "" ] ]
TITLE: P-CNN: Pose-based CNN Features for Action Recognition ABSTRACT: This work targets human action recognition in video. While recent methods typically represent actions by statistics of local video features, here we argue for the importance of a representation derived from human pose. To this end we propose a new Pose-based Convolutional Neural Network descriptor (P-CNN) for action recognition. The descriptor aggregates motion and appearance information along tracks of human body parts. We investigate different schemes of temporal aggregation and experiment with P-CNN features obtained both for automatically estimated and manually annotated human poses. We evaluate our method on the recent and challenging JHMDB and MPII Cooking datasets. For both datasets our method shows consistent improvement over the state of the art.
no_new_dataset
0.954137
1509.05982
Dan Stowell
Dan Stowell and Richard E. Turner
Denoising without access to clean data using a partitioned autoencoder
null
null
null
null
cs.NE cs.LG
http://creativecommons.org/licenses/by/4.0/
Training a denoising autoencoder neural network requires access to truly clean data, a requirement which is often impractical. To remedy this, we introduce a method to train an autoencoder using only noisy data, having examples with and without the signal class of interest. The autoencoder learns a partitioned representation of signal and noise, learning to reconstruct each separately. We illustrate the method by denoising birdsong audio (available abundantly in uncontrolled noisy datasets) using a convolutional autoencoder.
[ { "version": "v1", "created": "Sun, 20 Sep 2015 09:03:48 GMT" }, { "version": "v2", "created": "Tue, 22 Sep 2015 20:51:05 GMT" } ]
2015-09-24T00:00:00
[ [ "Stowell", "Dan", "" ], [ "Turner", "Richard E.", "" ] ]
TITLE: Denoising without access to clean data using a partitioned autoencoder ABSTRACT: Training a denoising autoencoder neural network requires access to truly clean data, a requirement which is often impractical. To remedy this, we introduce a method to train an autoencoder using only noisy data, having examples with and without the signal class of interest. The autoencoder learns a partitioned representation of signal and noise, learning to reconstruct each separately. We illustrate the method by denoising birdsong audio (available abundantly in uncontrolled noisy datasets) using a convolutional autoencoder.
no_new_dataset
0.949623
1509.06825
Lerrel Pinto Mr
Lerrel Pinto and Abhinav Gupta
Supersizing Self-supervision: Learning to Grasp from 50K Tries and 700 Robot Hours
null
null
null
null
cs.LG cs.CV cs.RO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Current learning-based robot grasping approaches exploit human-labeled datasets for training the models. However, there are two problems with such a methodology: (a) since each object can be grasped in multiple ways, manually labeling grasp locations is not a trivial task; (b) human labeling is biased by semantics. While there have been attempts to train robots using trial-and-error experiments, the amount of data used in such experiments remains substantially low and hence makes the learner prone to over-fitting. In this paper, we take the leap of increasing the available training data to 40 times more than prior work, leading to a dataset size of 50K data points collected over 700 hours of robot grasping attempts. This allows us to train a Convolutional Neural Network (CNN) for the task of predicting grasp locations without severe overfitting. In our formulation, we recast the regression problem to an 18-way binary classification over image patches. We also present a multi-stage learning approach where a CNN trained in one stage is used to collect hard negatives in subsequent stages. Our experiments clearly show the benefit of using large-scale datasets (and multi-stage training) for the task of grasping. We also compare to several baselines and show state-of-the-art performance on generalization to unseen objects for grasping.
[ { "version": "v1", "created": "Wed, 23 Sep 2015 02:08:02 GMT" } ]
2015-09-24T00:00:00
[ [ "Pinto", "Lerrel", "" ], [ "Gupta", "Abhinav", "" ] ]
TITLE: Supersizing Self-supervision: Learning to Grasp from 50K Tries and 700 Robot Hours ABSTRACT: Current learning-based robot grasping approaches exploit human-labeled datasets for training the models. However, there are two problems with such a methodology: (a) since each object can be grasped in multiple ways, manually labeling grasp locations is not a trivial task; (b) human labeling is biased by semantics. While there have been attempts to train robots using trial-and-error experiments, the amount of data used in such experiments remains substantially low and hence makes the learner prone to over-fitting. In this paper, we take the leap of increasing the available training data to 40 times more than prior work, leading to a dataset size of 50K data points collected over 700 hours of robot grasping attempts. This allows us to train a Convolutional Neural Network (CNN) for the task of predicting grasp locations without severe overfitting. In our formulation, we recast the regression problem to an 18-way binary classification over image patches. We also present a multi-stage learning approach where a CNN trained in one stage is used to collect hard negatives in subsequent stages. Our experiments clearly show the benefit of using large-scale datasets (and multi-stage training) for the task of grasping. We also compare to several baselines and show state-of-the-art performance on generalization to unseen objects for grasping.
no_new_dataset
0.839273
1509.07093
Pablo Estevez Prof.
David Nova and Pablo A. Estevez
A review of learning vector quantization classifiers
14 pages
Neural Computing & Applications, vol. 25, pp. 511-524, 2014
10.1007/s00521-013-1535-3
null
cs.LG astro-ph.IM cs.NE stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this work we present a review of the state of the art of Learning Vector Quantization (LVQ) classifiers. A taxonomy is proposed which integrates the most relevant LVQ approaches to date. The main concepts associated with modern LVQ approaches are defined. A comparison is made among eleven LVQ classifiers using one real-world and two artificial datasets.
[ { "version": "v1", "created": "Wed, 23 Sep 2015 18:46:31 GMT" } ]
2015-09-24T00:00:00
[ [ "Nova", "David", "" ], [ "Estevez", "Pablo A.", "" ] ]
TITLE: A review of learning vector quantization classifiers ABSTRACT: In this work we present a review of the state of the art of Learning Vector Quantization (LVQ) classifiers. A taxonomy is proposed which integrates the most relevant LVQ approaches to date. The main concepts associated with modern LVQ approaches are defined. A comparison is made among eleven LVQ classifiers using one real-world and two artificial datasets.
no_new_dataset
0.949248
1401.3632
Shaan Qamar
Shaan Qamar, Rajarshi Guhaniyogi, David B. Dunson
Bayesian Conditional Density Filtering
41 pages, 7 figures, 12 tables
null
null
null
stat.ML cs.LG stat.CO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a Conditional Density Filtering (C-DF) algorithm for efficient online Bayesian inference. C-DF adapts MCMC sampling to the online setting, sampling from approximations to conditional posterior distributions obtained by propagating surrogate conditional sufficient statistics (a function of data and parameter estimates) as new data arrive. These quantities eliminate the need to store or process the entire dataset simultaneously and offer a number of desirable features. Often, these include a reduction in memory requirements and runtime and improved mixing, along with state-of-the-art parameter inference and prediction. These improvements are demonstrated through several illustrative examples including an application to high dimensional compressed regression. Finally, we show that C-DF samples converge to the target posterior distribution asymptotically as sampling proceeds and more data arrives.
[ { "version": "v1", "created": "Wed, 15 Jan 2014 15:40:40 GMT" }, { "version": "v2", "created": "Thu, 16 Oct 2014 21:47:00 GMT" }, { "version": "v3", "created": "Tue, 22 Sep 2015 07:41:00 GMT" } ]
2015-09-23T00:00:00
[ [ "Qamar", "Shaan", "" ], [ "Guhaniyogi", "Rajarshi", "" ], [ "Dunson", "David B.", "" ] ]
TITLE: Bayesian Conditional Density Filtering ABSTRACT: We propose a Conditional Density Filtering (C-DF) algorithm for efficient online Bayesian inference. C-DF adapts MCMC sampling to the online setting, sampling from approximations to conditional posterior distributions obtained by propagating surrogate conditional sufficient statistics (a function of data and parameter estimates) as new data arrive. These quantities eliminate the need to store or process the entire dataset simultaneously and offer a number of desirable features. Often, these include a reduction in memory requirements and runtime and improved mixing, along with state-of-the-art parameter inference and prediction. These improvements are demonstrated through several illustrative examples including an application to high dimensional compressed regression. Finally, we show that C-DF samples converge to the target posterior distribution asymptotically as sampling proceeds and more data arrives.
no_new_dataset
0.950365
1403.5946
Jack Kelly
Jack Kelly and William Knottenbelt
Metadata for Energy Disaggregation
To appear in The 2nd IEEE International Workshop on Consumer Devices and Systems (CDS 2014) in V\"aster{\aa}s, Sweden
null
10.1109/COMPSACW.2014.97
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Energy disaggregation is the process of estimating the energy consumed by individual electrical appliances given only a time series of the whole-home power demand. Energy disaggregation researchers require datasets of the power demand from individual appliances and the whole-home power demand. Multiple such datasets have been released over the last few years but provide metadata in a disparate array of formats including CSV files and plain-text README files. At best, the lack of a standard metadata schema makes it unnecessarily time-consuming to write software to process multiple datasets and, at worse, the lack of a standard means that crucial information is simply absent from some datasets. We propose a metadata schema for representing appliances, meters, buildings, datasets, prior knowledge about appliances and appliance models. The schema is relational and provides a simple but powerful inheritance mechanism.
[ { "version": "v1", "created": "Mon, 24 Mar 2014 13:29:04 GMT" }, { "version": "v2", "created": "Wed, 2 Apr 2014 14:50:39 GMT" }, { "version": "v3", "created": "Mon, 19 May 2014 22:15:00 GMT" } ]
2015-09-23T00:00:00
[ [ "Kelly", "Jack", "" ], [ "Knottenbelt", "William", "" ] ]
TITLE: Metadata for Energy Disaggregation ABSTRACT: Energy disaggregation is the process of estimating the energy consumed by individual electrical appliances given only a time series of the whole-home power demand. Energy disaggregation researchers require datasets of the power demand from individual appliances and the whole-home power demand. Multiple such datasets have been released over the last few years but provide metadata in a disparate array of formats including CSV files and plain-text README files. At best, the lack of a standard metadata schema makes it unnecessarily time-consuming to write software to process multiple datasets and, at worse, the lack of a standard means that crucial information is simply absent from some datasets. We propose a metadata schema for representing appliances, meters, buildings, datasets, prior knowledge about appliances and appliance models. The schema is relational and provides a simple but powerful inheritance mechanism.
no_new_dataset
0.949435
1505.06606
Vasileios Belagiannis
Vasileios Belagiannis, Christian Rupprecht, Gustavo Carneiro, Nassir Navab
Robust Optimization for Deep Regression
Accepted for publication at the International Conference on Computer Vision (ICCV) 2015
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Convolutional Neural Networks (ConvNets) have successfully contributed to improve the accuracy of regression-based methods for computer vision tasks such as human pose estimation, landmark localization, and object detection. The network optimization has been usually performed with L2 loss and without considering the impact of outliers on the training process, where an outlier in this context is defined by a sample estimation that lies at an abnormal distance from the other training sample estimations in the objective space. In this work, we propose a regression model with ConvNets that achieves robustness to such outliers by minimizing Tukey's biweight function, an M-estimator robust to outliers, as the loss function for the ConvNet. In addition to the robust loss, we introduce a coarse-to-fine model, which processes input images of progressively higher resolutions for improving the accuracy of the regressed values. In our experiments, we demonstrate faster convergence and better generalization of our robust loss function for the tasks of human pose estimation and age estimation from face images. We also show that the combination of the robust loss function with the coarse-to-fine model produces comparable or better results than current state-of-the-art approaches in four publicly available human pose estimation datasets.
[ { "version": "v1", "created": "Mon, 25 May 2015 12:25:19 GMT" }, { "version": "v2", "created": "Tue, 22 Sep 2015 15:24:58 GMT" } ]
2015-09-23T00:00:00
[ [ "Belagiannis", "Vasileios", "" ], [ "Rupprecht", "Christian", "" ], [ "Carneiro", "Gustavo", "" ], [ "Navab", "Nassir", "" ] ]
TITLE: Robust Optimization for Deep Regression ABSTRACT: Convolutional Neural Networks (ConvNets) have successfully contributed to improve the accuracy of regression-based methods for computer vision tasks such as human pose estimation, landmark localization, and object detection. The network optimization has been usually performed with L2 loss and without considering the impact of outliers on the training process, where an outlier in this context is defined by a sample estimation that lies at an abnormal distance from the other training sample estimations in the objective space. In this work, we propose a regression model with ConvNets that achieves robustness to such outliers by minimizing Tukey's biweight function, an M-estimator robust to outliers, as the loss function for the ConvNet. In addition to the robust loss, we introduce a coarse-to-fine model, which processes input images of progressively higher resolutions for improving the accuracy of the regressed values. In our experiments, we demonstrate faster convergence and better generalization of our robust loss function for the tasks of human pose estimation and age estimation from face images. We also show that the combination of the robust loss function with the coarse-to-fine model produces comparable or better results than current state-of-the-art approaches in four publicly available human pose estimation datasets.
no_new_dataset
0.947672
1506.08259
Afshin Rahimi
Afshin Rahimi, Trevor Cohn, and Timothy Baldwin
Twitter User Geolocation Using a Unified Text and Network Prediction Model
To appear in ACL 2015, Proceedings of the 53rd Annual Meeting of the Association for Computational Linguistics (ACL 2015)
null
null
null
cs.CL cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a label propagation approach to geolocation prediction based on Modified Adsorption, with two enhancements:(1) the removal of "celebrity" nodes to increase location homophily and boost tractability, and (2) he incorporation of text-based geolocation priors for test users. Experiments over three Twitter benchmark datasets achieve state-of-the-art results, and demonstrate the effectiveness of the enhancements.
[ { "version": "v1", "created": "Sat, 27 Jun 2015 04:51:18 GMT" }, { "version": "v2", "created": "Tue, 30 Jun 2015 00:43:39 GMT" }, { "version": "v3", "created": "Tue, 22 Sep 2015 01:14:20 GMT" } ]
2015-09-23T00:00:00
[ [ "Rahimi", "Afshin", "" ], [ "Cohn", "Trevor", "" ], [ "Baldwin", "Timothy", "" ] ]
TITLE: Twitter User Geolocation Using a Unified Text and Network Prediction Model ABSTRACT: We propose a label propagation approach to geolocation prediction based on Modified Adsorption, with two enhancements:(1) the removal of "celebrity" nodes to increase location homophily and boost tractability, and (2) he incorporation of text-based geolocation priors for test users. Experiments over three Twitter benchmark datasets achieve state-of-the-art results, and demonstrate the effectiveness of the enhancements.
no_new_dataset
0.957198
1508.07647
Lamberto Ballan
Justin Johnson and Lamberto Ballan and Fei-Fei Li
Love Thy Neighbors: Image Annotation by Exploiting Image Metadata
Accepted to ICCV 2015
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Some images that are difficult to recognize on their own may become more clear in the context of a neighborhood of related images with similar social-network metadata. We build on this intuition to improve multilabel image annotation. Our model uses image metadata nonparametrically to generate neighborhoods of related images using Jaccard similarities, then uses a deep neural network to blend visual information from the image and its neighbors. Prior work typically models image metadata parametrically, in contrast, our nonparametric treatment allows our model to perform well even when the vocabulary of metadata changes between training and testing. We perform comprehensive experiments on the NUS-WIDE dataset, where we show that our model outperforms state-of-the-art methods for multilabel image annotation even when our model is forced to generalize to new types of metadata.
[ { "version": "v1", "created": "Sun, 30 Aug 2015 23:34:13 GMT" }, { "version": "v2", "created": "Tue, 22 Sep 2015 00:12:06 GMT" } ]
2015-09-23T00:00:00
[ [ "Johnson", "Justin", "" ], [ "Ballan", "Lamberto", "" ], [ "Li", "Fei-Fei", "" ] ]
TITLE: Love Thy Neighbors: Image Annotation by Exploiting Image Metadata ABSTRACT: Some images that are difficult to recognize on their own may become more clear in the context of a neighborhood of related images with similar social-network metadata. We build on this intuition to improve multilabel image annotation. Our model uses image metadata nonparametrically to generate neighborhoods of related images using Jaccard similarities, then uses a deep neural network to blend visual information from the image and its neighbors. Prior work typically models image metadata parametrically, in contrast, our nonparametric treatment allows our model to perform well even when the vocabulary of metadata changes between training and testing. We perform comprehensive experiments on the NUS-WIDE dataset, where we show that our model outperforms state-of-the-art methods for multilabel image annotation even when our model is forced to generalize to new types of metadata.
no_new_dataset
0.950869
1509.02412
Mortaza Doulaty
Mortaza Doulaty, Oscar Saz, Thomas Hain
Unsupervised Domain Discovery using Latent Dirichlet Allocation for Acoustic Modelling in Speech Recognition
null
16th Interspeech.Proc. (2015) 3640-3644, Dresden, Germany
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Speech recognition systems are often highly domain dependent, a fact widely reported in the literature. However the concept of domain is complex and not bound to clear criteria. Hence it is often not evident if data should be considered to be out-of-domain. While both acoustic and language models can be domain specific, work in this paper concentrates on acoustic modelling. We present a novel method to perform unsupervised discovery of domains using Latent Dirichlet Allocation (LDA) modelling. Here a set of hidden domains is assumed to exist in the data, whereby each audio segment can be considered to be a weighted mixture of domain properties. The classification of audio segments into domains allows the creation of domain specific acoustic models for automatic speech recognition. Experiments are conducted on a dataset of diverse speech data covering speech from radio and TV broadcasts, telephone conversations, meetings, lectures and read speech, with a joint training set of 60 hours and a test set of 6 hours. Maximum A Posteriori (MAP) adaptation to LDA based domains was shown to yield relative Word Error Rate (WER) improvements of up to 16% relative, compared to pooled training, and up to 10%, compared with models adapted with human-labelled prior domain knowledge.
[ { "version": "v1", "created": "Tue, 8 Sep 2015 15:29:23 GMT" } ]
2015-09-23T00:00:00
[ [ "Doulaty", "Mortaza", "" ], [ "Saz", "Oscar", "" ], [ "Hain", "Thomas", "" ] ]
TITLE: Unsupervised Domain Discovery using Latent Dirichlet Allocation for Acoustic Modelling in Speech Recognition ABSTRACT: Speech recognition systems are often highly domain dependent, a fact widely reported in the literature. However the concept of domain is complex and not bound to clear criteria. Hence it is often not evident if data should be considered to be out-of-domain. While both acoustic and language models can be domain specific, work in this paper concentrates on acoustic modelling. We present a novel method to perform unsupervised discovery of domains using Latent Dirichlet Allocation (LDA) modelling. Here a set of hidden domains is assumed to exist in the data, whereby each audio segment can be considered to be a weighted mixture of domain properties. The classification of audio segments into domains allows the creation of domain specific acoustic models for automatic speech recognition. Experiments are conducted on a dataset of diverse speech data covering speech from radio and TV broadcasts, telephone conversations, meetings, lectures and read speech, with a joint training set of 60 hours and a test set of 6 hours. Maximum A Posteriori (MAP) adaptation to LDA based domains was shown to yield relative Word Error Rate (WER) improvements of up to 16% relative, compared to pooled training, and up to 10%, compared with models adapted with human-labelled prior domain knowledge.
no_new_dataset
0.9463
1509.06458
Jian Sun
Zuoqiang Shi and Jian Sun and Minghao Tian
Harmonic Extension
10 pages, 2 figures
null
null
null
cs.LG math.NA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we consider the harmonic extension problem, which is widely used in many applications of machine learning. We find that the transitional method of graph Laplacian fails to produce a good approximation of the classical harmonic function. To tackle this problem, we propose a new method called the point integral method (PIM). We consider the harmonic extension problem from the point of view of solving PDEs on manifolds. The basic idea of the PIM method is to approximate the harmonicity using an integral equation, which is easy to be discretized from points. Based on the integral equation, we explain the reason why the transitional graph Laplacian may fail to approximate the harmonicity in the classical sense and propose a different approach which we call the volume constraint method (VCM). Theoretically, both the PIM and the VCM computes a harmonic function with convergence guarantees, and practically, they are both simple, which amount to solve a linear system. One important application of the harmonic extension in machine learning is semi-supervised learning. We run a popular semi-supervised learning algorithm by Zhu et al. over a couple of well-known datasets and compare the performance of the aforementioned approaches. Our experiments show the PIM performs the best.
[ { "version": "v1", "created": "Tue, 22 Sep 2015 04:13:38 GMT" } ]
2015-09-23T00:00:00
[ [ "Shi", "Zuoqiang", "" ], [ "Sun", "Jian", "" ], [ "Tian", "Minghao", "" ] ]
TITLE: Harmonic Extension ABSTRACT: In this paper, we consider the harmonic extension problem, which is widely used in many applications of machine learning. We find that the transitional method of graph Laplacian fails to produce a good approximation of the classical harmonic function. To tackle this problem, we propose a new method called the point integral method (PIM). We consider the harmonic extension problem from the point of view of solving PDEs on manifolds. The basic idea of the PIM method is to approximate the harmonicity using an integral equation, which is easy to be discretized from points. Based on the integral equation, we explain the reason why the transitional graph Laplacian may fail to approximate the harmonicity in the classical sense and propose a different approach which we call the volume constraint method (VCM). Theoretically, both the PIM and the VCM computes a harmonic function with convergence guarantees, and practically, they are both simple, which amount to solve a linear system. One important application of the harmonic extension in machine learning is semi-supervised learning. We run a popular semi-supervised learning algorithm by Zhu et al. over a couple of well-known datasets and compare the performance of the aforementioned approaches. Our experiments show the PIM performs the best.
no_new_dataset
0.948632
1509.06470
Yiyi Liao
Yiyi Liao, Sarath Kodagoda, Yue Wang, Lei Shi, Yong Liu
Understand Scene Categories by Objects: A Semantic Regularized Scene Classifier Using Convolutional Neural Networks
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Scene classification is a fundamental perception task for environmental understanding in today's robotics. In this paper, we have attempted to exploit the use of popular machine learning technique of deep learning to enhance scene understanding, particularly in robotics applications. As scene images have larger diversity than the iconic object images, it is more challenging for deep learning methods to automatically learn features from scene images with less samples. Inspired by human scene understanding based on object knowledge, we address the problem of scene classification by encouraging deep neural networks to incorporate object-level information. This is implemented with a regularization of semantic segmentation. With only 5 thousand training images, as opposed to 2.5 million images, we show the proposed deep architecture achieves superior scene classification results to the state-of-the-art on a publicly available SUN RGB-D dataset. In addition, performance of semantic segmentation, the regularizer, also reaches a new record with refinement derived from predicted scene labels. Finally, we apply our SUN RGB-D dataset trained model to a mobile robot captured images to classify scenes in our university demonstrating the generalization ability of the proposed algorithm.
[ { "version": "v1", "created": "Tue, 22 Sep 2015 05:43:27 GMT" } ]
2015-09-23T00:00:00
[ [ "Liao", "Yiyi", "" ], [ "Kodagoda", "Sarath", "" ], [ "Wang", "Yue", "" ], [ "Shi", "Lei", "" ], [ "Liu", "Yong", "" ] ]
TITLE: Understand Scene Categories by Objects: A Semantic Regularized Scene Classifier Using Convolutional Neural Networks ABSTRACT: Scene classification is a fundamental perception task for environmental understanding in today's robotics. In this paper, we have attempted to exploit the use of popular machine learning technique of deep learning to enhance scene understanding, particularly in robotics applications. As scene images have larger diversity than the iconic object images, it is more challenging for deep learning methods to automatically learn features from scene images with less samples. Inspired by human scene understanding based on object knowledge, we address the problem of scene classification by encouraging deep neural networks to incorporate object-level information. This is implemented with a regularization of semantic segmentation. With only 5 thousand training images, as opposed to 2.5 million images, we show the proposed deep architecture achieves superior scene classification results to the state-of-the-art on a publicly available SUN RGB-D dataset. In addition, performance of semantic segmentation, the regularizer, also reaches a new record with refinement derived from predicted scene labels. Finally, we apply our SUN RGB-D dataset trained model to a mobile robot captured images to classify scenes in our university demonstrating the generalization ability of the proposed algorithm.
no_new_dataset
0.946001
1509.06589
Nicol\`o Navarin
Giovanni Da San Martino, Nicol\`o Navarin, and Alessandro Sperduti
Graph Kernels exploiting Weisfeiler-Lehman Graph Isomorphism Test Extensions
null
Neural Information Processing, Volume 8835 of the series Lecture Notes in Computer Science pp 93-100, 2014 Springer International Publishing
10.1007/978-3-319-12640-1_12
null
cs.LG cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we present a novel graph kernel framework inspired the by the Weisfeiler-Lehman (WL) isomorphism tests. Any WL test comprises a relabelling phase of the nodes based on test-specific information extracted from the graph, for example the set of neighbours of a node. We defined a novel relabelling and derived two kernels of the framework from it. The novel kernels are very fast to compute and achieve state-of-the-art results on five real-world datasets.
[ { "version": "v1", "created": "Tue, 22 Sep 2015 13:21:08 GMT" } ]
2015-09-23T00:00:00
[ [ "Martino", "Giovanni Da San", "" ], [ "Navarin", "Nicolò", "" ], [ "Sperduti", "Alessandro", "" ] ]
TITLE: Graph Kernels exploiting Weisfeiler-Lehman Graph Isomorphism Test Extensions ABSTRACT: In this paper we present a novel graph kernel framework inspired the by the Weisfeiler-Lehman (WL) isomorphism tests. Any WL test comprises a relabelling phase of the nodes based on test-specific information extracted from the graph, for example the set of neighbours of a node. We defined a novel relabelling and derived two kernels of the framework from it. The novel kernels are very fast to compute and achieve state-of-the-art results on five real-world datasets.
no_new_dataset
0.94545
1311.4764
Dan Stowell
Dan Stowell and Mark D. Plumbley
Large-scale analysis of frequency modulation in birdsong databases
null
Methods in Ecology and Evolution, Volume 5, Issue 9, pages 901-912, September 2014
10.1111/2041-210X.12223
null
cs.SD
http://creativecommons.org/licenses/by/3.0/
Birdsong often contains large amounts of rapid frequency modulation (FM). It is believed that the use or otherwise of FM is adaptive to the acoustic environment, and also that there are specific social uses of FM such as trills in aggressive territorial encounters. Yet temporal fine detail of FM is often absent or obscured in standard audio signal analysis methods such as Fourier analysis or linear prediction. Hence it is important to consider high resolution signal processing techniques for analysis of FM in bird vocalisations. If such methods can be applied at big data scales, this offers a further advantage as large datasets become available. We introduce methods from the signal processing literature which can go beyond spectrogram representations to analyse the fine modulations present in a signal at very short timescales. Focusing primarily on the genus Phylloscopus, we investigate which of a set of four analysis methods most strongly captures the species signal encoded in birdsong. In order to find tools useful in practical analysis of large databases, we also study the computational time taken by the methods, and their robustness to additive noise and MP3 compression. We find three methods which can robustly represent species-correlated FM attributes, and that the simplest method tested also appears to perform the best. We find that features representing the extremes of FM encode species identity supplementary to that captured in frequency features, whereas bandwidth features do not encode additional information. Large-scale FM analysis can efficiently extract information useful for bioacoustic studies, in addition to measures more commonly used to characterise vocalisations.
[ { "version": "v1", "created": "Tue, 19 Nov 2013 15:02:55 GMT" } ]
2015-09-22T00:00:00
[ [ "Stowell", "Dan", "" ], [ "Plumbley", "Mark D.", "" ] ]
TITLE: Large-scale analysis of frequency modulation in birdsong databases ABSTRACT: Birdsong often contains large amounts of rapid frequency modulation (FM). It is believed that the use or otherwise of FM is adaptive to the acoustic environment, and also that there are specific social uses of FM such as trills in aggressive territorial encounters. Yet temporal fine detail of FM is often absent or obscured in standard audio signal analysis methods such as Fourier analysis or linear prediction. Hence it is important to consider high resolution signal processing techniques for analysis of FM in bird vocalisations. If such methods can be applied at big data scales, this offers a further advantage as large datasets become available. We introduce methods from the signal processing literature which can go beyond spectrogram representations to analyse the fine modulations present in a signal at very short timescales. Focusing primarily on the genus Phylloscopus, we investigate which of a set of four analysis methods most strongly captures the species signal encoded in birdsong. In order to find tools useful in practical analysis of large databases, we also study the computational time taken by the methods, and their robustness to additive noise and MP3 compression. We find three methods which can robustly represent species-correlated FM attributes, and that the simplest method tested also appears to perform the best. We find that features representing the extremes of FM encode species identity supplementary to that captured in frequency features, whereas bandwidth features do not encode additional information. Large-scale FM analysis can efficiently extract information useful for bioacoustic studies, in addition to measures more commonly used to characterise vocalisations.
no_new_dataset
0.933734
1503.05638
Y. William Yu
Y. William Yu, Noah M. Daniels, David Christian Danko, Bonnie Berger
Entropy-scaling search of massive biological data
Including supplement: 41 pages, 6 figures, 4 tables, 1 box
Cell Systems, Volume 1, Issue 2, 130-140, 2015
10.1016/j.cels.2015.08.004
null
cs.DS q-bio.GN
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many datasets exhibit a well-defined structure that can be exploited to design faster search tools, but it is not always clear when such acceleration is possible. Here, we introduce a framework for similarity search based on characterizing a dataset's entropy and fractal dimension. We prove that searching scales in time with metric entropy (number of covering hyperspheres), if the fractal dimension of the dataset is low, and scales in space with the sum of metric entropy and information-theoretic entropy (randomness of the data). Using these ideas, we present accelerated versions of standard tools, with no loss in specificity and little loss in sensitivity, for use in three domains---high-throughput drug screening (Ammolite, 150x speedup), metagenomics (MICA, 3.5x speedup of DIAMOND [3,700x BLASTX]), and protein structure search (esFragBag, 10x speedup of FragBag). Our framework can be used to achieve "compressive omics," and the general theory can be readily applied to data science problems outside of biology.
[ { "version": "v1", "created": "Thu, 19 Mar 2015 02:54:21 GMT" }, { "version": "v2", "created": "Mon, 21 Sep 2015 04:31:50 GMT" } ]
2015-09-22T00:00:00
[ [ "Yu", "Y. William", "" ], [ "Daniels", "Noah M.", "" ], [ "Danko", "David Christian", "" ], [ "Berger", "Bonnie", "" ] ]
TITLE: Entropy-scaling search of massive biological data ABSTRACT: Many datasets exhibit a well-defined structure that can be exploited to design faster search tools, but it is not always clear when such acceleration is possible. Here, we introduce a framework for similarity search based on characterizing a dataset's entropy and fractal dimension. We prove that searching scales in time with metric entropy (number of covering hyperspheres), if the fractal dimension of the dataset is low, and scales in space with the sum of metric entropy and information-theoretic entropy (randomness of the data). Using these ideas, we present accelerated versions of standard tools, with no loss in specificity and little loss in sensitivity, for use in three domains---high-throughput drug screening (Ammolite, 150x speedup), metagenomics (MICA, 3.5x speedup of DIAMOND [3,700x BLASTX]), and protein structure search (esFragBag, 10x speedup of FragBag). Our framework can be used to achieve "compressive omics," and the general theory can be readily applied to data science problems outside of biology.
no_new_dataset
0.949248
1504.03071
Jaeyong Sung
Jaeyong Sung, Seok Hyun Jin, Ashutosh Saxena
Robobarista: Object Part based Transfer of Manipulation Trajectories from Crowd-sourcing in 3D Pointclouds
In International Symposium on Robotics Research (ISRR) 2015
null
null
null
cs.RO cs.AI cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
There is a large variety of objects and appliances in human environments, such as stoves, coffee dispensers, juice extractors, and so on. It is challenging for a roboticist to program a robot for each of these object types and for each of their instantiations. In this work, we present a novel approach to manipulation planning based on the idea that many household objects share similarly-operated object parts. We formulate the manipulation planning as a structured prediction problem and design a deep learning model that can handle large noise in the manipulation demonstrations and learns features from three different modalities: point-clouds, language and trajectory. In order to collect a large number of manipulation demonstrations for different objects, we developed a new crowd-sourcing platform called Robobarista. We test our model on our dataset consisting of 116 objects with 249 parts along with 250 language instructions, for which there are 1225 crowd-sourced manipulation demonstrations. We further show that our robot can even manipulate objects it has never seen before.
[ { "version": "v1", "created": "Mon, 13 Apr 2015 06:25:42 GMT" }, { "version": "v2", "created": "Fri, 18 Sep 2015 23:43:19 GMT" } ]
2015-09-22T00:00:00
[ [ "Sung", "Jaeyong", "" ], [ "Jin", "Seok Hyun", "" ], [ "Saxena", "Ashutosh", "" ] ]
TITLE: Robobarista: Object Part based Transfer of Manipulation Trajectories from Crowd-sourcing in 3D Pointclouds ABSTRACT: There is a large variety of objects and appliances in human environments, such as stoves, coffee dispensers, juice extractors, and so on. It is challenging for a roboticist to program a robot for each of these object types and for each of their instantiations. In this work, we present a novel approach to manipulation planning based on the idea that many household objects share similarly-operated object parts. We formulate the manipulation planning as a structured prediction problem and design a deep learning model that can handle large noise in the manipulation demonstrations and learns features from three different modalities: point-clouds, language and trajectory. In order to collect a large number of manipulation demonstrations for different objects, we developed a new crowd-sourcing platform called Robobarista. We test our model on our dataset consisting of 116 objects with 249 parts along with 250 language instructions, for which there are 1225 crowd-sourced manipulation demonstrations. We further show that our robot can even manipulate objects it has never seen before.
new_dataset
0.960025
1504.06201
Gedas Bertasius
Gedas Bertasius, Jianbo Shi and Lorenzo Torresani
High-for-Low and Low-for-High: Efficient Boundary Detection from Deep Object Features and its Applications to High-Level Vision
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Most of the current boundary detection systems rely exclusively on low-level features, such as color and texture. However, perception studies suggest that humans employ object-level reasoning when judging if a particular pixel is a boundary. Inspired by this observation, in this work we show how to predict boundaries by exploiting object-level features from a pretrained object-classification network. Our method can be viewed as a "High-for-Low" approach where high-level object features inform the low-level boundary detection process. Our model achieves state-of-the-art performance on an established boundary detection benchmark and it is efficient to run. Additionally, we show that due to the semantic nature of our boundaries we can use them to aid a number of high-level vision tasks. We demonstrate that using our boundaries we improve the performance of state-of-the-art methods on the problems of semantic boundary labeling, semantic segmentation and object proposal generation. We can view this process as a "Low-for-High" scheme, where low-level boundaries aid high-level vision tasks. Thus, our contributions include a boundary detection system that is accurate, efficient, generalizes well to multiple datasets, and is also shown to improve existing state-of-the-art high-level vision methods on three distinct tasks.
[ { "version": "v1", "created": "Thu, 23 Apr 2015 14:35:12 GMT" }, { "version": "v2", "created": "Fri, 1 May 2015 13:46:18 GMT" }, { "version": "v3", "created": "Mon, 21 Sep 2015 17:48:23 GMT" } ]
2015-09-22T00:00:00
[ [ "Bertasius", "Gedas", "" ], [ "Shi", "Jianbo", "" ], [ "Torresani", "Lorenzo", "" ] ]
TITLE: High-for-Low and Low-for-High: Efficient Boundary Detection from Deep Object Features and its Applications to High-Level Vision ABSTRACT: Most of the current boundary detection systems rely exclusively on low-level features, such as color and texture. However, perception studies suggest that humans employ object-level reasoning when judging if a particular pixel is a boundary. Inspired by this observation, in this work we show how to predict boundaries by exploiting object-level features from a pretrained object-classification network. Our method can be viewed as a "High-for-Low" approach where high-level object features inform the low-level boundary detection process. Our model achieves state-of-the-art performance on an established boundary detection benchmark and it is efficient to run. Additionally, we show that due to the semantic nature of our boundaries we can use them to aid a number of high-level vision tasks. We demonstrate that using our boundaries we improve the performance of state-of-the-art methods on the problems of semantic boundary labeling, semantic segmentation and object proposal generation. We can view this process as a "Low-for-High" scheme, where low-level boundaries aid high-level vision tasks. Thus, our contributions include a boundary detection system that is accurate, efficient, generalizes well to multiple datasets, and is also shown to improve existing state-of-the-art high-level vision methods on three distinct tasks.
no_new_dataset
0.947235
1507.05739
Vein Kong
Emrah Budur, Seungmin Lee, Vein S. Kong
Structural Analysis of Criminal Network and Predicting Hidden Links using Machine Learning
null
null
null
null
cs.SI physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Analysis of criminal networks is inherently difficult because of the nature of the topic. Criminal networks are covert and most of the information is not publicly available. This leads to small datasets available for analysis. The available criminal network datasets consists of entities, i.e. individual or organizations, which are linked to each other. The links between entities indicates that there is a connection between these entities such as involvement in the same criminal event, having commercial ties, and/or memberships in the same criminal organization. Because of incognito criminal activities, there could be many hidden links from entities to entities, which makes the publicly available criminal networks incomplete. Revealing hidden links introduces new information, e.g. affiliation of a suspected individual with a criminal organization, which may not be known with public information. What will we be able to find if we can run analysis on a larger dataset and use link prediction to reveal the implicit connections? We plan to answer this question by using a dataset that is an order of magnitude more than what is used in most criminal networks analysis. And by using machine learning techniques, we will convert a link prediction problem to a binary classification problem. We plan to reveal hidden links and potentially hidden key attributes of the criminal network. With a more complete picture of the network, we can potentially use this data to thwart criminal organizations and/or take a Pareto approach in targeting key nodes. We conclude our analysis with an effective destruction strategy to weaken criminal networks and prove the effectiveness of revealing hidden links when attacking to criminal networks.
[ { "version": "v1", "created": "Tue, 21 Jul 2015 08:10:12 GMT" }, { "version": "v2", "created": "Wed, 22 Jul 2015 07:03:01 GMT" }, { "version": "v3", "created": "Mon, 21 Sep 2015 15:52:08 GMT" } ]
2015-09-22T00:00:00
[ [ "Budur", "Emrah", "" ], [ "Lee", "Seungmin", "" ], [ "Kong", "Vein S.", "" ] ]
TITLE: Structural Analysis of Criminal Network and Predicting Hidden Links using Machine Learning ABSTRACT: Analysis of criminal networks is inherently difficult because of the nature of the topic. Criminal networks are covert and most of the information is not publicly available. This leads to small datasets available for analysis. The available criminal network datasets consists of entities, i.e. individual or organizations, which are linked to each other. The links between entities indicates that there is a connection between these entities such as involvement in the same criminal event, having commercial ties, and/or memberships in the same criminal organization. Because of incognito criminal activities, there could be many hidden links from entities to entities, which makes the publicly available criminal networks incomplete. Revealing hidden links introduces new information, e.g. affiliation of a suspected individual with a criminal organization, which may not be known with public information. What will we be able to find if we can run analysis on a larger dataset and use link prediction to reveal the implicit connections? We plan to answer this question by using a dataset that is an order of magnitude more than what is used in most criminal networks analysis. And by using machine learning techniques, we will convert a link prediction problem to a binary classification problem. We plan to reveal hidden links and potentially hidden key attributes of the criminal network. With a more complete picture of the network, we can potentially use this data to thwart criminal organizations and/or take a Pareto approach in targeting key nodes. We conclude our analysis with an effective destruction strategy to weaken criminal networks and prove the effectiveness of revealing hidden links when attacking to criminal networks.
no_new_dataset
0.91804
1509.04874
Lichao Huang
Lichao Huang and Yi Yang and Yafeng Deng and Yinan Yu
DenseBox: Unifying Landmark Localization with End to End Object Detection
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
How can a single fully convolutional neural network (FCN) perform on object detection? We introduce DenseBox, a unified end-to-end FCN framework that directly predicts bounding boxes and object class confidences through all locations and scales of an image. Our contribution is two-fold. First, we show that a single FCN, if designed and optimized carefully, can detect multiple different objects extremely accurately and efficiently. Second, we show that when incorporating with landmark localization during multi-task learning, DenseBox further improves object detection accuray. We present experimental results on public benchmark datasets including MALF face detection and KITTI car detection, that indicate our DenseBox is the state-of-the-art system for detecting challenging objects such as faces and cars.
[ { "version": "v1", "created": "Wed, 16 Sep 2015 10:30:37 GMT" }, { "version": "v2", "created": "Thu, 17 Sep 2015 00:20:08 GMT" }, { "version": "v3", "created": "Sat, 19 Sep 2015 02:36:04 GMT" } ]
2015-09-22T00:00:00
[ [ "Huang", "Lichao", "" ], [ "Yang", "Yi", "" ], [ "Deng", "Yafeng", "" ], [ "Yu", "Yinan", "" ] ]
TITLE: DenseBox: Unifying Landmark Localization with End to End Object Detection ABSTRACT: How can a single fully convolutional neural network (FCN) perform on object detection? We introduce DenseBox, a unified end-to-end FCN framework that directly predicts bounding boxes and object class confidences through all locations and scales of an image. Our contribution is two-fold. First, we show that a single FCN, if designed and optimized carefully, can detect multiple different objects extremely accurately and efficiently. Second, we show that when incorporating with landmark localization during multi-task learning, DenseBox further improves object detection accuray. We present experimental results on public benchmark datasets including MALF face detection and KITTI car detection, that indicate our DenseBox is the state-of-the-art system for detecting challenging objects such as faces and cars.
no_new_dataset
0.947527
1509.05935
Shang-Tse Chen
Paras Jain, Shang-Tse Chen, Mozhgan Azimpourkivi, Duen Horng Chau, Bogdan Carbunar
Spotting Suspicious Reviews via (Quasi-)clique Extraction
Appeared in IEEE Symposium on Security and Privacy 2015
null
null
null
cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
How to tell if a review is real or fake? What does the underworld of fraudulent reviewing look like? Detecting suspicious reviews has become a major issue for many online services. We propose the use of a clique-finding approach to discover well-organized suspicious reviewers. From a Yelp dataset with over one million reviews, we construct multiple Reviewer Similarity graphs to link users that have unusually similar behavior: two reviewers are connected in the graph if they have reviewed the same set of venues within a few days. From these graphs, our algorithms extracted many large cliques and quasi-cliques, the largest one containing a striking 11 users who coordinated their review activities in identical ways. Among the detected cliques, a large portion contain Yelp Scouts who are paid by Yelp to review venues in new areas. Our work sheds light on their little-known operation.
[ { "version": "v1", "created": "Sat, 19 Sep 2015 21:01:38 GMT" } ]
2015-09-22T00:00:00
[ [ "Jain", "Paras", "" ], [ "Chen", "Shang-Tse", "" ], [ "Azimpourkivi", "Mozhgan", "" ], [ "Chau", "Duen Horng", "" ], [ "Carbunar", "Bogdan", "" ] ]
TITLE: Spotting Suspicious Reviews via (Quasi-)clique Extraction ABSTRACT: How to tell if a review is real or fake? What does the underworld of fraudulent reviewing look like? Detecting suspicious reviews has become a major issue for many online services. We propose the use of a clique-finding approach to discover well-organized suspicious reviewers. From a Yelp dataset with over one million reviews, we construct multiple Reviewer Similarity graphs to link users that have unusually similar behavior: two reviewers are connected in the graph if they have reviewed the same set of venues within a few days. From these graphs, our algorithms extracted many large cliques and quasi-cliques, the largest one containing a striking 11 users who coordinated their review activities in identical ways. Among the detected cliques, a large portion contain Yelp Scouts who are paid by Yelp to review venues in new areas. Our work sheds light on their little-known operation.
no_new_dataset
0.939471
1509.06033
Arsalan Mousavian
Arsalan Mousavian, Jana Kosecka
Deep Convolutional Features for Image Based Retrieval and Scene Categorization
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Several recent approaches showed how the representations learned by Convolutional Neural Networks can be repurposed for novel tasks. Most commonly it has been shown that the activation features of the last fully connected layers (fc7 or fc6) of the network, followed by a linear classifier outperform the state-of-the-art on several recognition challenge datasets. Instead of recognition, this paper focuses on the image retrieval problem and proposes a examines alternative pooling strategies derived for CNN features. The presented scheme uses the features maps from an earlier layer 5 of the CNN architecture, which has been shown to preserve coarse spatial information and is semantically meaningful. We examine several pooling strategies and demonstrate superior performance on the image retrieval task (INRIA Holidays) at the fraction of the computational cost, while using a relatively small memory requirements. In addition to retrieval, we see similar efficiency gains on the SUN397 scene categorization dataset, demonstrating wide applicability of this simple strategy. We also introduce and evaluate a novel GeoPlaces5K dataset from different geographical locations in the world for image retrieval that stresses more dramatic changes in appearance and viewpoint.
[ { "version": "v1", "created": "Sun, 20 Sep 2015 17:56:57 GMT" } ]
2015-09-22T00:00:00
[ [ "Mousavian", "Arsalan", "" ], [ "Kosecka", "Jana", "" ] ]
TITLE: Deep Convolutional Features for Image Based Retrieval and Scene Categorization ABSTRACT: Several recent approaches showed how the representations learned by Convolutional Neural Networks can be repurposed for novel tasks. Most commonly it has been shown that the activation features of the last fully connected layers (fc7 or fc6) of the network, followed by a linear classifier outperform the state-of-the-art on several recognition challenge datasets. Instead of recognition, this paper focuses on the image retrieval problem and proposes a examines alternative pooling strategies derived for CNN features. The presented scheme uses the features maps from an earlier layer 5 of the CNN architecture, which has been shown to preserve coarse spatial information and is semantically meaningful. We examine several pooling strategies and demonstrate superior performance on the image retrieval task (INRIA Holidays) at the fraction of the computational cost, while using a relatively small memory requirements. In addition to retrieval, we see similar efficiency gains on the SUN397 scene categorization dataset, demonstrating wide applicability of this simple strategy. We also introduce and evaluate a novel GeoPlaces5K dataset from different geographical locations in the world for image retrieval that stresses more dramatic changes in appearance and viewpoint.
new_dataset
0.877214
1509.06066
Mahyar Najibi
Mahyar Najibi, Mohammad Rastegari, Larry S. Davis
On Large-Scale Retrieval: Binary or n-ary Coding?
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The growing amount of data available in modern-day datasets makes the need to efficiently search and retrieve information. To make large-scale search feasible, Distance Estimation and Subset Indexing are the main approaches. Although binary coding has been popular for implementing both techniques, n-ary coding (known as Product Quantization) is also very effective for Distance Estimation. However, their relative performance has not been studied for Subset Indexing. We investigate whether binary or n-ary coding works better under different retrieval strategies. This leads to the design of a new n-ary coding method, "Linear Subspace Quantization (LSQ)" which, unlike other n-ary encoders, can be used as a similarity-preserving embedding. Experiments on image retrieval show that when Distance Estimation is used, n-ary LSQ outperforms other methods. However, when Subset Indexing is applied, interestingly, binary codings are more effective and binary LSQ achieves the best accuracy.
[ { "version": "v1", "created": "Sun, 20 Sep 2015 22:32:23 GMT" } ]
2015-09-22T00:00:00
[ [ "Najibi", "Mahyar", "" ], [ "Rastegari", "Mohammad", "" ], [ "Davis", "Larry S.", "" ] ]
TITLE: On Large-Scale Retrieval: Binary or n-ary Coding? ABSTRACT: The growing amount of data available in modern-day datasets makes the need to efficiently search and retrieve information. To make large-scale search feasible, Distance Estimation and Subset Indexing are the main approaches. Although binary coding has been popular for implementing both techniques, n-ary coding (known as Product Quantization) is also very effective for Distance Estimation. However, their relative performance has not been studied for Subset Indexing. We investigate whether binary or n-ary coding works better under different retrieval strategies. This leads to the design of a new n-ary coding method, "Linear Subspace Quantization (LSQ)" which, unlike other n-ary encoders, can be used as a similarity-preserving embedding. Experiments on image retrieval show that when Distance Estimation is used, n-ary LSQ outperforms other methods. However, when Subset Indexing is applied, interestingly, binary codings are more effective and binary LSQ achieves the best accuracy.
no_new_dataset
0.949435
1509.06109
Dustin Freeman
Dustin Freeman, Ricardo Jota, Daniel Vogel, Daniel Wigdor, Ravin Balakrishnan
A Dataset of Naturally Occurring, Whole-Body Background Activity to Reduce Gesture Conflicts
null
null
null
null
cs.HC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In real settings, natural body movements can be erroneously recognized by whole-body input systems as explicit input actions. We call body activity not intended as input actions "background activity." We argue that understanding background activity is crucial to the success of always-available whole-body input in the real world. To operationalize this argument, we contribute a reusable study methodology and software tools to generate standardized background activity datasets composed of data from multiple Kinect cameras, a Vicon tracker, and two high-definition video cameras. Using our methodology, we create an example background activity dataset for a television-oriented living room setting. We use this dataset to demonstrate how it can be used to redesign a gestural interaction vocabulary to minimize conflicts with the real world. The software tools and initial living room dataset are publicly available (http://www.dgp.toronto.edu/~dustin/backgroundactivity/).
[ { "version": "v1", "created": "Mon, 21 Sep 2015 04:40:31 GMT" } ]
2015-09-22T00:00:00
[ [ "Freeman", "Dustin", "" ], [ "Jota", "Ricardo", "" ], [ "Vogel", "Daniel", "" ], [ "Wigdor", "Daniel", "" ], [ "Balakrishnan", "Ravin", "" ] ]
TITLE: A Dataset of Naturally Occurring, Whole-Body Background Activity to Reduce Gesture Conflicts ABSTRACT: In real settings, natural body movements can be erroneously recognized by whole-body input systems as explicit input actions. We call body activity not intended as input actions "background activity." We argue that understanding background activity is crucial to the success of always-available whole-body input in the real world. To operationalize this argument, we contribute a reusable study methodology and software tools to generate standardized background activity datasets composed of data from multiple Kinect cameras, a Vicon tracker, and two high-definition video cameras. Using our methodology, we create an example background activity dataset for a television-oriented living room setting. We use this dataset to demonstrate how it can be used to redesign a gestural interaction vocabulary to minimize conflicts with the real world. The software tools and initial living room dataset are publicly available (http://www.dgp.toronto.edu/~dustin/backgroundactivity/).
new_dataset
0.956553
1509.06163
Shubhendu Trivedi
Shubhendu Trivedi, Zachary A. Pardos, Neil T. Heffernan
The Utility of Clustering in Prediction Tasks
An experimental research report, dated 11 September 2011
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We explore the utility of clustering in reducing error in various prediction tasks. Previous work has hinted at the improvement in prediction accuracy attributed to clustering algorithms if used to pre-process the data. In this work we more deeply investigate the direct utility of using clustering to improve prediction accuracy and provide explanations for why this may be so. We look at a number of datasets, run k-means at different scales and for each scale we train predictors. This produces k sets of predictions. These predictions are then combined by a na\"ive ensemble. We observed that this use of a predictor in conjunction with clustering improved the prediction accuracy in most datasets. We believe this indicates the predictive utility of exploiting structure in the data and the data compression handed over by clustering. We also found that using this method improves upon the prediction of even a Random Forests predictor which suggests this method is providing a novel, and useful source of variance in the prediction process.
[ { "version": "v1", "created": "Mon, 21 Sep 2015 09:42:50 GMT" } ]
2015-09-22T00:00:00
[ [ "Trivedi", "Shubhendu", "" ], [ "Pardos", "Zachary A.", "" ], [ "Heffernan", "Neil T.", "" ] ]
TITLE: The Utility of Clustering in Prediction Tasks ABSTRACT: We explore the utility of clustering in reducing error in various prediction tasks. Previous work has hinted at the improvement in prediction accuracy attributed to clustering algorithms if used to pre-process the data. In this work we more deeply investigate the direct utility of using clustering to improve prediction accuracy and provide explanations for why this may be so. We look at a number of datasets, run k-means at different scales and for each scale we train predictors. This produces k sets of predictions. These predictions are then combined by a na\"ive ensemble. We observed that this use of a predictor in conjunction with clustering improved the prediction accuracy in most datasets. We believe this indicates the predictive utility of exploiting structure in the data and the data compression handed over by clustering. We also found that using this method improves upon the prediction of even a Random Forests predictor which suggests this method is providing a novel, and useful source of variance in the prediction process.
no_new_dataset
0.951142
1509.06243
Albert Gordo
Albert Gordo and Jon Almazan and Naila Murray and Florent Perronnin
LEWIS: Latent Embeddings for Word Images and their Semantics
Accepted for publication at the International Conference on Computer Vision (ICCV) 2015
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The goal of this work is to bring semantics into the tasks of text recognition and retrieval in natural images. Although text recognition and retrieval have received a lot of attention in recent years, previous works have focused on recognizing or retrieving exactly the same word used as a query, without taking the semantics into consideration. In this paper, we ask the following question: \emph{can we predict semantic concepts directly from a word image, without explicitly trying to transcribe the word image or its characters at any point?} For this goal we propose a convolutional neural network (CNN) with a weighted ranking loss objective that ensures that the concepts relevant to the query image are ranked ahead of those that are not relevant. This can also be interpreted as learning a Euclidean space where word images and concepts are jointly embedded. This model is learned in an end-to-end manner, from image pixels to semantic concepts, using a dataset of synthetically generated word images and concepts mined from a lexical database (WordNet). Our results show that, despite the complexity of the task, word images and concepts can indeed be associated with a high degree of accuracy
[ { "version": "v1", "created": "Mon, 21 Sep 2015 14:32:43 GMT" } ]
2015-09-22T00:00:00
[ [ "Gordo", "Albert", "" ], [ "Almazan", "Jon", "" ], [ "Murray", "Naila", "" ], [ "Perronnin", "Florent", "" ] ]
TITLE: LEWIS: Latent Embeddings for Word Images and their Semantics ABSTRACT: The goal of this work is to bring semantics into the tasks of text recognition and retrieval in natural images. Although text recognition and retrieval have received a lot of attention in recent years, previous works have focused on recognizing or retrieving exactly the same word used as a query, without taking the semantics into consideration. In this paper, we ask the following question: \emph{can we predict semantic concepts directly from a word image, without explicitly trying to transcribe the word image or its characters at any point?} For this goal we propose a convolutional neural network (CNN) with a weighted ranking loss objective that ensures that the concepts relevant to the query image are ranked ahead of those that are not relevant. This can also be interpreted as learning a Euclidean space where word images and concepts are jointly embedded. This model is learned in an end-to-end manner, from image pixels to semantic concepts, using a dataset of synthetically generated word images and concepts mined from a lexical database (WordNet). Our results show that, despite the complexity of the task, word images and concepts can indeed be associated with a high degree of accuracy
new_dataset
0.962778
1509.06254
Pablo Rodriguez-Mier
Pablo Rodriguez-Mier, Manuel Mucientes, Manuel Lama
Hybrid Optimization Algorithm for Large-Scale QoS-Aware Service Composition
Preprint accepted to appear in IEEE Transactions on Services Computing 2015
null
10.1109/TSC.2015.2480396
null
cs.AI cs.NI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we present a hybrid approach for automatic composition of Web services that generates semantic input-output based compositions with optimal end-to-end QoS, minimizing the number of services of the resulting composition. The proposed approach has four main steps: 1) generation of the composition graph for a request; 2) computation of the optimal composition that minimizes a single objective QoS function; 3) multi-step optimizations to reduce the search space by identifying equivalent and dominated services; and 4) hybrid local-global search to extract the optimal QoS with the minimum number of services. An extensive validation with the datasets of the Web Service Challenge 2009-2010 and randomly generated datasets shows that: 1) the combination of local and global optimization is a general and powerful technique to extract optimal compositions in diverse scenarios; and 2) the hybrid strategy performs better than the state-of-the-art, obtaining solutions with less services and optimal QoS.
[ { "version": "v1", "created": "Mon, 21 Sep 2015 14:56:28 GMT" } ]
2015-09-22T00:00:00
[ [ "Rodriguez-Mier", "Pablo", "" ], [ "Mucientes", "Manuel", "" ], [ "Lama", "Manuel", "" ] ]
TITLE: Hybrid Optimization Algorithm for Large-Scale QoS-Aware Service Composition ABSTRACT: In this paper we present a hybrid approach for automatic composition of Web services that generates semantic input-output based compositions with optimal end-to-end QoS, minimizing the number of services of the resulting composition. The proposed approach has four main steps: 1) generation of the composition graph for a request; 2) computation of the optimal composition that minimizes a single objective QoS function; 3) multi-step optimizations to reduce the search space by identifying equivalent and dominated services; and 4) hybrid local-global search to extract the optimal QoS with the minimum number of services. An extensive validation with the datasets of the Web Service Challenge 2009-2010 and randomly generated datasets shows that: 1) the combination of local and global optimization is a general and powerful technique to extract optimal compositions in diverse scenarios; and 2) the hybrid strategy performs better than the state-of-the-art, obtaining solutions with less services and optimal QoS.
no_new_dataset
0.945096
1502.00956
Raul Mur-Artal
Raul Mur-Artal, J. M. M. Montiel and Juan D. Tardos
ORB-SLAM: a Versatile and Accurate Monocular SLAM System
17 pages. 13 figures. IEEE Transactions on Robotics, 2015. Project webpage (videos, code): http://webdiis.unizar.es/~raulmur/orbslam/
null
10.1109/TRO.2015.2463671
null
cs.RO cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents ORB-SLAM, a feature-based monocular SLAM system that operates in real time, in small and large, indoor and outdoor environments. The system is robust to severe motion clutter, allows wide baseline loop closing and relocalization, and includes full automatic initialization. Building on excellent algorithms of recent years, we designed from scratch a novel system that uses the same features for all SLAM tasks: tracking, mapping, relocalization, and loop closing. A survival of the fittest strategy that selects the points and keyframes of the reconstruction leads to excellent robustness and generates a compact and trackable map that only grows if the scene content changes, allowing lifelong operation. We present an exhaustive evaluation in 27 sequences from the most popular datasets. ORB-SLAM achieves unprecedented performance with respect to other state-of-the-art monocular SLAM approaches. For the benefit of the community, we make the source code public.
[ { "version": "v1", "created": "Tue, 3 Feb 2015 18:52:23 GMT" }, { "version": "v2", "created": "Fri, 18 Sep 2015 09:50:11 GMT" } ]
2015-09-21T00:00:00
[ [ "Mur-Artal", "Raul", "" ], [ "Montiel", "J. M. M.", "" ], [ "Tardos", "Juan D.", "" ] ]
TITLE: ORB-SLAM: a Versatile and Accurate Monocular SLAM System ABSTRACT: This paper presents ORB-SLAM, a feature-based monocular SLAM system that operates in real time, in small and large, indoor and outdoor environments. The system is robust to severe motion clutter, allows wide baseline loop closing and relocalization, and includes full automatic initialization. Building on excellent algorithms of recent years, we designed from scratch a novel system that uses the same features for all SLAM tasks: tracking, mapping, relocalization, and loop closing. A survival of the fittest strategy that selects the points and keyframes of the reconstruction leads to excellent robustness and generates a compact and trackable map that only grows if the scene content changes, allowing lifelong operation. We present an exhaustive evaluation in 27 sequences from the most popular datasets. ORB-SLAM achieves unprecedented performance with respect to other state-of-the-art monocular SLAM approaches. For the benefit of the community, we make the source code public.
no_new_dataset
0.947088
1506.03478
Lucas Theis
Lucas Theis and Matthias Bethge
Generative Image Modeling Using Spatial LSTMs
null
null
null
null
stat.ML cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Modeling the distribution of natural images is challenging, partly because of strong statistical dependencies which can extend over hundreds of pixels. Recurrent neural networks have been successful in capturing long-range dependencies in a number of problems but only recently have found their way into generative image models. We here introduce a recurrent image model based on multi-dimensional long short-term memory units which are particularly suited for image modeling due to their spatial structure. Our model scales to images of arbitrary size and its likelihood is computationally tractable. We find that it outperforms the state of the art in quantitative comparisons on several image datasets and produces promising results when used for texture synthesis and inpainting.
[ { "version": "v1", "created": "Wed, 10 Jun 2015 20:56:14 GMT" }, { "version": "v2", "created": "Fri, 18 Sep 2015 08:06:06 GMT" } ]
2015-09-21T00:00:00
[ [ "Theis", "Lucas", "" ], [ "Bethge", "Matthias", "" ] ]
TITLE: Generative Image Modeling Using Spatial LSTMs ABSTRACT: Modeling the distribution of natural images is challenging, partly because of strong statistical dependencies which can extend over hundreds of pixels. Recurrent neural networks have been successful in capturing long-range dependencies in a number of problems but only recently have found their way into generative image models. We here introduce a recurrent image model based on multi-dimensional long short-term memory units which are particularly suited for image modeling due to their spatial structure. Our model scales to images of arbitrary size and its likelihood is computationally tractable. We find that it outperforms the state of the art in quantitative comparisons on several image datasets and produces promising results when used for texture synthesis and inpainting.
no_new_dataset
0.950824
1509.05153
Wei Pan
Wei Pan, Ye Yuan, Lennart Ljung, Jorge Goncalves and Guy-Bart Stan
Identifying Biochemical Reaction Networks From Heterogeneous Datasets
null
null
null
null
cs.SY
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we propose a new method to identify biochemical reaction networks (i.e. both reactions and kinetic parameters) from heterogeneous datasets. Such datasets can contain (a) data from several replicates of an experiment performed on a biological system; (b) data measured from a biochemical network subjected to different experimental conditions, for example, changes/perturbations in biological inductions, temperature, gene knock-out, gene over-expression, etc. Simultaneous integration of various datasets to perform system identification has the potential to avoid non-identifiability issues typically arising when only single datasets are used.
[ { "version": "v1", "created": "Thu, 17 Sep 2015 07:51:58 GMT" }, { "version": "v2", "created": "Fri, 18 Sep 2015 00:22:18 GMT" } ]
2015-09-21T00:00:00
[ [ "Pan", "Wei", "" ], [ "Yuan", "Ye", "" ], [ "Ljung", "Lennart", "" ], [ "Goncalves", "Jorge", "" ], [ "Stan", "Guy-Bart", "" ] ]
TITLE: Identifying Biochemical Reaction Networks From Heterogeneous Datasets ABSTRACT: In this paper, we propose a new method to identify biochemical reaction networks (i.e. both reactions and kinetic parameters) from heterogeneous datasets. Such datasets can contain (a) data from several replicates of an experiment performed on a biological system; (b) data measured from a biochemical network subjected to different experimental conditions, for example, changes/perturbations in biological inductions, temperature, gene knock-out, gene over-expression, etc. Simultaneous integration of various datasets to perform system identification has the potential to avoid non-identifiability issues typically arising when only single datasets are used.
no_new_dataset
0.957517
1509.05186
Shicong Liu
Shicong Liu, Junru Shao, Hongtao Lu
Accelerated Distance Computation with Encoding Tree for High Dimensional Data
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a novel distance to calculate distance between high dimensional vector pairs, utilizing vector quantization generated encodings. Vector quantization based methods are successful in handling large scale high dimensional data. These methods compress vectors into short encodings, and allow efficient distance computation between an uncompressed vector and compressed dataset without decompressing explicitly. However for large datasets, these distance computing methods perform excessive computations. We avoid excessive computations by storing the encodings on an Encoding Tree(E-Tree), interestingly the memory consumption is also lowered. We also propose Encoding Forest(E-Forest) to further lower the computation cost. E-Tree and E-Forest is compatible with various existing quantization-based methods. We show by experiments our methods speed-up distance computing for high dimensional data drastically, and various existing algorithms can benefit from our methods.
[ { "version": "v1", "created": "Thu, 17 Sep 2015 09:54:33 GMT" }, { "version": "v2", "created": "Fri, 18 Sep 2015 06:40:22 GMT" } ]
2015-09-21T00:00:00
[ [ "Liu", "Shicong", "" ], [ "Shao", "Junru", "" ], [ "Lu", "Hongtao", "" ] ]
TITLE: Accelerated Distance Computation with Encoding Tree for High Dimensional Data ABSTRACT: We propose a novel distance to calculate distance between high dimensional vector pairs, utilizing vector quantization generated encodings. Vector quantization based methods are successful in handling large scale high dimensional data. These methods compress vectors into short encodings, and allow efficient distance computation between an uncompressed vector and compressed dataset without decompressing explicitly. However for large datasets, these distance computing methods perform excessive computations. We avoid excessive computations by storing the encodings on an Encoding Tree(E-Tree), interestingly the memory consumption is also lowered. We also propose Encoding Forest(E-Forest) to further lower the computation cost. E-Tree and E-Forest is compatible with various existing quantization-based methods. We show by experiments our methods speed-up distance computing for high dimensional data drastically, and various existing algorithms can benefit from our methods.
no_new_dataset
0.947332
1509.05567
Dipasree Pal
Dipasree Pal, Mandar Mitra and Samar Bhattacharya
Exploring Query Categorisation for Query Expansion: A Study
null
null
null
null
cs.IR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The vocabulary mismatch problem is one of the important challenges facing traditional keyword-based Information Retrieval Systems. The aim of query expansion (QE) is to reduce this query-document mismatch by adding related or synonymous words or phrases to the query. Several existing query expansion algorithms have proved their merit, but they are not uniformly beneficial for all kinds of queries. Our long-term goal is to formulate methods for applying QE techniques tailored to individual queries, rather than applying the same general QE method to all queries. As an initial step, we have proposed a taxonomy of query classes (from a QE perspective) in this report. We have discussed the properties of each query class with examples. We have also discussed some QE strategies that might be effective for each query category. In future work, we intend to test the proposed techniques using standard datasets, and to explore automatic query categorisation methods.
[ { "version": "v1", "created": "Fri, 18 Sep 2015 10:04:09 GMT" } ]
2015-09-21T00:00:00
[ [ "Pal", "Dipasree", "" ], [ "Mitra", "Mandar", "" ], [ "Bhattacharya", "Samar", "" ] ]
TITLE: Exploring Query Categorisation for Query Expansion: A Study ABSTRACT: The vocabulary mismatch problem is one of the important challenges facing traditional keyword-based Information Retrieval Systems. The aim of query expansion (QE) is to reduce this query-document mismatch by adding related or synonymous words or phrases to the query. Several existing query expansion algorithms have proved their merit, but they are not uniformly beneficial for all kinds of queries. Our long-term goal is to formulate methods for applying QE techniques tailored to individual queries, rather than applying the same general QE method to all queries. As an initial step, we have proposed a taxonomy of query classes (from a QE perspective) in this report. We have discussed the properties of each query class with examples. We have also discussed some QE strategies that might be effective for each query category. In future work, we intend to test the proposed techniques using standard datasets, and to explore automatic query categorisation methods.
no_new_dataset
0.946051
1509.05736
Issa Atoum
Issa Atoum, Chih How Bong, Narayanan Kulathuramaiyer
Building a Pilot Software Quality-in-Use Benchmark Dataset
6 pages,3 figures, conference Proceedings of 9th International Conference on IT in Asia CITA (2015)
null
null
null
cs.SE cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Prepared domain specific datasets plays an important role to supervised learning approaches. In this article a new sentence dataset for software quality-in-use is proposed. Three experts were chosen to annotate the data using a proposed annotation scheme. Then the data were reconciled in a (no match eliminate) process to reduce bias. The Kappa, k statistics revealed an acceptable level of agreement; moderate to substantial agreement between the experts. The built data can be used to evaluate software quality-in-use models in sentiment analysis models. Moreover, the annotation scheme can be used to extend the current dataset.
[ { "version": "v1", "created": "Fri, 18 Sep 2015 18:19:48 GMT" } ]
2015-09-21T00:00:00
[ [ "Atoum", "Issa", "" ], [ "Bong", "Chih How", "" ], [ "Kulathuramaiyer", "Narayanan", "" ] ]
TITLE: Building a Pilot Software Quality-in-Use Benchmark Dataset ABSTRACT: Prepared domain specific datasets plays an important role to supervised learning approaches. In this article a new sentence dataset for software quality-in-use is proposed. Three experts were chosen to annotate the data using a proposed annotation scheme. Then the data were reconciled in a (no match eliminate) process to reduce bias. The Kappa, k statistics revealed an acceptable level of agreement; moderate to substantial agreement between the experts. The built data can be used to evaluate software quality-in-use models in sentiment analysis models. Moreover, the annotation scheme can be used to extend the current dataset.
new_dataset
0.957794
1509.05194
Shicong Liu
Shicong Liu, Junru Shao, Hongtao Lu
HCLAE: High Capacity Locally Aggregating Encodings for Approximate Nearest Neighbor Search
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Vector quantization-based approaches are successful to solve Approximate Nearest Neighbor (ANN) problems which are critical to many applications. The idea is to generate effective encodings to allow fast distance approximation. We propose quantization-based methods should partition the data space finely and exhibit locality of the dataset to allow efficient non-exhaustive search. In this paper, we introduce the concept of High Capacity Locality Aggregating Encodings (HCLAE) to this end, and propose Dictionary Annealing (DA) to learn HCLAE by a simulated annealing procedure. The quantization error is lower than other state-of-the-art. The algorithms of DA can be easily extended to an online learning scheme, allowing effective handle of large scale data. Further, we propose Aggregating-Tree (A-Tree), a non-exhaustive search method using HCLAE to perform efficient ANN-Search. A-Tree achieves magnitudes of speed-up on ANN-Search tasks, compared to the state-of-the-art.
[ { "version": "v1", "created": "Thu, 17 Sep 2015 10:18:05 GMT" } ]
2015-09-18T00:00:00
[ [ "Liu", "Shicong", "" ], [ "Shao", "Junru", "" ], [ "Lu", "Hongtao", "" ] ]
TITLE: HCLAE: High Capacity Locally Aggregating Encodings for Approximate Nearest Neighbor Search ABSTRACT: Vector quantization-based approaches are successful to solve Approximate Nearest Neighbor (ANN) problems which are critical to many applications. The idea is to generate effective encodings to allow fast distance approximation. We propose quantization-based methods should partition the data space finely and exhibit locality of the dataset to allow efficient non-exhaustive search. In this paper, we introduce the concept of High Capacity Locality Aggregating Encodings (HCLAE) to this end, and propose Dictionary Annealing (DA) to learn HCLAE by a simulated annealing procedure. The quantization error is lower than other state-of-the-art. The algorithms of DA can be easily extended to an online learning scheme, allowing effective handle of large scale data. Further, we propose Aggregating-Tree (A-Tree), a non-exhaustive search method using HCLAE to perform efficient ANN-Search. A-Tree achieves magnitudes of speed-up on ANN-Search tasks, compared to the state-of-the-art.
no_new_dataset
0.949949
1509.05195
Shicong Liu
Shicong Liu, Hongtao Lu, Junru Shao
Improved Residual Vector Quantization for High-dimensional Approximate Nearest Neighbor Search
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Quantization methods have been introduced to perform large scale approximate nearest search tasks. Residual Vector Quantization (RVQ) is one of the effective quantization methods. RVQ uses a multi-stage codebook learning scheme to lower the quantization error stage by stage. However, there are two major limitations for RVQ when applied to on high-dimensional approximate nearest neighbor search: 1. The performance gain diminishes quickly with added stages. 2. Encoding a vector with RVQ is actually NP-hard. In this paper, we propose an improved residual vector quantization (IRVQ) method, our IRVQ learns codebook with a hybrid method of subspace clustering and warm-started k-means on each stage to prevent performance gain from dropping, and uses a multi-path encoding scheme to encode a vector with lower distortion. Experimental results on the benchmark datasets show that our method gives substantially improves RVQ and delivers better performance compared to the state-of-the-art.
[ { "version": "v1", "created": "Thu, 17 Sep 2015 10:19:37 GMT" } ]
2015-09-18T00:00:00
[ [ "Liu", "Shicong", "" ], [ "Lu", "Hongtao", "" ], [ "Shao", "Junru", "" ] ]
TITLE: Improved Residual Vector Quantization for High-dimensional Approximate Nearest Neighbor Search ABSTRACT: Quantization methods have been introduced to perform large scale approximate nearest search tasks. Residual Vector Quantization (RVQ) is one of the effective quantization methods. RVQ uses a multi-stage codebook learning scheme to lower the quantization error stage by stage. However, there are two major limitations for RVQ when applied to on high-dimensional approximate nearest neighbor search: 1. The performance gain diminishes quickly with added stages. 2. Encoding a vector with RVQ is actually NP-hard. In this paper, we propose an improved residual vector quantization (IRVQ) method, our IRVQ learns codebook with a hybrid method of subspace clustering and warm-started k-means on each stage to prevent performance gain from dropping, and uses a multi-path encoding scheme to encode a vector with lower distortion. Experimental results on the benchmark datasets show that our method gives substantially improves RVQ and delivers better performance compared to the state-of-the-art.
no_new_dataset
0.950319
1509.05366
Nazli Ikizler-Cinbis
Gokhan Tanisik, Cemil Zalluhoglu, Nazli Ikizler-Cinbis
Facial Descriptors for Human Interaction Recognition In Still Images
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents a novel approach in a rarely studied area of computer vision: Human interaction recognition in still images. We explore whether the facial regions and their spatial configurations contribute to the recognition of interactions. In this respect, our method involves extraction of several visual features from the facial regions, as well as incorporation of scene characteristics and deep features to the recognition. Extracted multiple features are utilized within a discriminative learning framework for recognizing interactions between people. Our designed facial descriptors are based on the observation that relative positions, size and locations of the faces are likely to be important for characterizing human interactions. Since there is no available dataset in this relatively new domain, a comprehensive new dataset which includes several images of human interactions is collected. Our experimental results show that faces and scene characteristics contain important information to recognize interactions between people.
[ { "version": "v1", "created": "Thu, 17 Sep 2015 18:40:15 GMT" } ]
2015-09-18T00:00:00
[ [ "Tanisik", "Gokhan", "" ], [ "Zalluhoglu", "Cemil", "" ], [ "Ikizler-Cinbis", "Nazli", "" ] ]
TITLE: Facial Descriptors for Human Interaction Recognition In Still Images ABSTRACT: This paper presents a novel approach in a rarely studied area of computer vision: Human interaction recognition in still images. We explore whether the facial regions and their spatial configurations contribute to the recognition of interactions. In this respect, our method involves extraction of several visual features from the facial regions, as well as incorporation of scene characteristics and deep features to the recognition. Extracted multiple features are utilized within a discriminative learning framework for recognizing interactions between people. Our designed facial descriptors are based on the observation that relative positions, size and locations of the faces are likely to be important for characterizing human interactions. Since there is no available dataset in this relatively new domain, a comprehensive new dataset which includes several images of human interactions is collected. Our experimental results show that faces and scene characteristics contain important information to recognize interactions between people.
new_dataset
0.958265
1406.2639
Holger Roth
Holger R. Roth and Le Lu and Ari Seff and Kevin M. Cherry and Joanne Hoffman and Shijun Wang and Jiamin Liu and Evrim Turkbey and Ronald M. Summers
A New 2.5D Representation for Lymph Node Detection using Random Sets of Deep Convolutional Neural Network Observations
This article will be presented at MICCAI (Medical Image Computing and Computer-Assisted Interventions) 2014
Medical Image Computing and Computer-Assisted Intervention - MICCAI 2014 Volume 8673 of the series Lecture Notes in Computer Science pp 520-527
10.1007/978-3-319-10404-1_65
null
cs.CV cs.LG cs.NE
http://creativecommons.org/licenses/publicdomain/
Automated Lymph Node (LN) detection is an important clinical diagnostic task but very challenging due to the low contrast of surrounding structures in Computed Tomography (CT) and to their varying sizes, poses, shapes and sparsely distributed locations. State-of-the-art studies show the performance range of 52.9% sensitivity at 3.1 false-positives per volume (FP/vol.), or 60.9% at 6.1 FP/vol. for mediastinal LN, by one-shot boosting on 3D HAAR features. In this paper, we first operate a preliminary candidate generation stage, towards 100% sensitivity at the cost of high FP levels (40 per patient), to harvest volumes of interest (VOI). Our 2.5D approach consequently decomposes any 3D VOI by resampling 2D reformatted orthogonal views N times, via scale, random translations, and rotations with respect to the VOI centroid coordinates. These random views are then used to train a deep Convolutional Neural Network (CNN) classifier. In testing, the CNN is employed to assign LN probabilities for all N random views that can be simply averaged (as a set) to compute the final classification probability per VOI. We validate the approach on two datasets: 90 CT volumes with 388 mediastinal LNs and 86 patients with 595 abdominal LNs. We achieve sensitivities of 70%/83% at 3 FP/vol. and 84%/90% at 6 FP/vol. in mediastinum and abdomen respectively, which drastically improves over the previous state-of-the-art work.
[ { "version": "v1", "created": "Fri, 6 Jun 2014 22:43:42 GMT" } ]
2015-09-17T00:00:00
[ [ "Roth", "Holger R.", "" ], [ "Lu", "Le", "" ], [ "Seff", "Ari", "" ], [ "Cherry", "Kevin M.", "" ], [ "Hoffman", "Joanne", "" ], [ "Wang", "Shijun", "" ], [ "Liu", "Jiamin", "" ], [ "Turkbey", "Evrim", "" ], [ "Summers", "Ronald M.", "" ] ]
TITLE: A New 2.5D Representation for Lymph Node Detection using Random Sets of Deep Convolutional Neural Network Observations ABSTRACT: Automated Lymph Node (LN) detection is an important clinical diagnostic task but very challenging due to the low contrast of surrounding structures in Computed Tomography (CT) and to their varying sizes, poses, shapes and sparsely distributed locations. State-of-the-art studies show the performance range of 52.9% sensitivity at 3.1 false-positives per volume (FP/vol.), or 60.9% at 6.1 FP/vol. for mediastinal LN, by one-shot boosting on 3D HAAR features. In this paper, we first operate a preliminary candidate generation stage, towards 100% sensitivity at the cost of high FP levels (40 per patient), to harvest volumes of interest (VOI). Our 2.5D approach consequently decomposes any 3D VOI by resampling 2D reformatted orthogonal views N times, via scale, random translations, and rotations with respect to the VOI centroid coordinates. These random views are then used to train a deep Convolutional Neural Network (CNN) classifier. In testing, the CNN is employed to assign LN probabilities for all N random views that can be simply averaged (as a set) to compute the final classification probability per VOI. We validate the approach on two datasets: 90 CT volumes with 388 mediastinal LNs and 86 patients with 595 abdominal LNs. We achieve sensitivities of 70%/83% at 3 FP/vol. and 84%/90% at 6 FP/vol. in mediastinum and abdomen respectively, which drastically improves over the previous state-of-the-art work.
no_new_dataset
0.950641
1505.03101
Albert Mero\~no-Pe\~nuela
Albert Mero\~no-Pe\~nuela, Christophe Gu\'eret and Stefan Schlobach
Release Early, Release Often: Predicting Change in Versioned Knowledge Organization Systems on the Web
16 pages, 6 figures, ISWC 2015 conference pre-print The paper has been withdrawn due to significant overlap with a subsequent paper submitted to a conference for review
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Semantic Web is built on top of Knowledge Organization Systems (KOS) (vocabularies, ontologies, concept schemes) that provide a structured, interoperable and distributed access to Linked Data on the Web. The maintenance of these KOS over time has produced a number of KOS version chains: subsequent unique version identifiers to unique states of a KOS. However, the release of new KOS versions pose challenges to both KOS publishers and users. For publishers, updating a KOS is a knowledge intensive task that requires a lot of manual effort, often implying deep deliberation on the set of changes to introduce. For users that link their datasets to these KOS, a new version compromises the validity of their links, often creating ramifications. In this paper we describe a method to automatically detect which parts of a Web KOS are likely to change in a next version, using supervised learning on past versions in the KOS version chain. We use a set of ontology change features to model and predict change in arbitrary Web KOS. We apply our method on 139 varied datasets systematically retrieved from the Semantic Web, obtaining robust results at correctly predicting change. To illustrate the accuracy, genericity and domain independence of the method, we study the relationship between its effectiveness and several characterizations of the evaluated datasets, finding that predictors like the number of versions in a chain and their release frequency have a fundamental impact in predictability of change in Web KOS. Consequently, we argue for adopting a release early, release often philosophy in Web KOS development cycles.
[ { "version": "v1", "created": "Tue, 12 May 2015 18:03:21 GMT" }, { "version": "v2", "created": "Tue, 15 Sep 2015 20:11:34 GMT" } ]
2015-09-17T00:00:00
[ [ "Meroño-Peñuela", "Albert", "" ], [ "Guéret", "Christophe", "" ], [ "Schlobach", "Stefan", "" ] ]
TITLE: Release Early, Release Often: Predicting Change in Versioned Knowledge Organization Systems on the Web ABSTRACT: The Semantic Web is built on top of Knowledge Organization Systems (KOS) (vocabularies, ontologies, concept schemes) that provide a structured, interoperable and distributed access to Linked Data on the Web. The maintenance of these KOS over time has produced a number of KOS version chains: subsequent unique version identifiers to unique states of a KOS. However, the release of new KOS versions pose challenges to both KOS publishers and users. For publishers, updating a KOS is a knowledge intensive task that requires a lot of manual effort, often implying deep deliberation on the set of changes to introduce. For users that link their datasets to these KOS, a new version compromises the validity of their links, often creating ramifications. In this paper we describe a method to automatically detect which parts of a Web KOS are likely to change in a next version, using supervised learning on past versions in the KOS version chain. We use a set of ontology change features to model and predict change in arbitrary Web KOS. We apply our method on 139 varied datasets systematically retrieved from the Semantic Web, obtaining robust results at correctly predicting change. To illustrate the accuracy, genericity and domain independence of the method, we study the relationship between its effectiveness and several characterizations of the evaluated datasets, finding that predictors like the number of versions in a chain and their release frequency have a fundamental impact in predictability of change in Web KOS. Consequently, we argue for adopting a release early, release often philosophy in Web KOS development cycles.
no_new_dataset
0.955858
1509.03755
Gabriel Prat
Gabriel Prat Masramon and Llu\'is A. Belanche Mu\~noz
Toward better feature weighting algorithms: a focus on Relief
null
null
null
null
cs.LG
http://creativecommons.org/licenses/by/4.0/
Feature weighting algorithms try to solve a problem of great importance nowadays in machine learning: The search of a relevance measure for the features of a given domain. This relevance is primarily used for feature selection as feature weighting can be seen as a generalization of it, but it is also useful to better understand a problem's domain or to guide an inductor in its learning process. Relief family of algorithms are proven to be very effective in this task. Some other feature weighting methods are reviewed in order to give some context and then the different existing extensions to the original algorithm are explained. One of Relief's known issues is the performance degradation of its estimates when redundant features are present. A novel theoretical definition of redundancy level is given in order to guide the work towards an extension of the algorithm that is more robust against redundancy. A new extension is presented that aims for improving the algorithms performance. Some experiments were driven to test this new extension against the existing ones with a set of artificial and real datasets and denoted that in certain cases it improves the weight's estimation accuracy.
[ { "version": "v1", "created": "Sat, 12 Sep 2015 15:10:15 GMT" }, { "version": "v2", "created": "Wed, 16 Sep 2015 11:58:32 GMT" } ]
2015-09-17T00:00:00
[ [ "Masramon", "Gabriel Prat", "" ], [ "Muñoz", "Lluís A. Belanche", "" ] ]
TITLE: Toward better feature weighting algorithms: a focus on Relief ABSTRACT: Feature weighting algorithms try to solve a problem of great importance nowadays in machine learning: The search of a relevance measure for the features of a given domain. This relevance is primarily used for feature selection as feature weighting can be seen as a generalization of it, but it is also useful to better understand a problem's domain or to guide an inductor in its learning process. Relief family of algorithms are proven to be very effective in this task. Some other feature weighting methods are reviewed in order to give some context and then the different existing extensions to the original algorithm are explained. One of Relief's known issues is the performance degradation of its estimates when redundant features are present. A novel theoretical definition of redundancy level is given in order to guide the work towards an extension of the algorithm that is more robust against redundancy. A new extension is presented that aims for improving the algorithms performance. Some experiments were driven to test this new extension against the existing ones with a set of artificial and real datasets and denoted that in certain cases it improves the weight's estimation accuracy.
no_new_dataset
0.941061
1509.04612
Alan Mosca
Alan Mosca and George D. Magoulas
Adapting Resilient Propagation for Deep Learning
Published in the proceedings of the UK workshop on Computational Intelligence 2015 (UKCI)
null
null
null
cs.NE cs.CV cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Resilient Propagation (Rprop) algorithm has been very popular for backpropagation training of multilayer feed-forward neural networks in various applications. The standard Rprop however encounters difficulties in the context of deep neural networks as typically happens with gradient-based learning algorithms. In this paper, we propose a modification of the Rprop that combines standard Rprop steps with a special drop out technique. We apply the method for training Deep Neural Networks as standalone components and in ensemble formulations. Results on the MNIST dataset show that the proposed modification alleviates standard Rprop's problems demonstrating improved learning speed and accuracy.
[ { "version": "v1", "created": "Tue, 15 Sep 2015 15:55:29 GMT" }, { "version": "v2", "created": "Wed, 16 Sep 2015 11:45:48 GMT" } ]
2015-09-17T00:00:00
[ [ "Mosca", "Alan", "" ], [ "Magoulas", "George D.", "" ] ]
TITLE: Adapting Resilient Propagation for Deep Learning ABSTRACT: The Resilient Propagation (Rprop) algorithm has been very popular for backpropagation training of multilayer feed-forward neural networks in various applications. The standard Rprop however encounters difficulties in the context of deep neural networks as typically happens with gradient-based learning algorithms. In this paper, we propose a modification of the Rprop that combines standard Rprop steps with a special drop out technique. We apply the method for training Deep Neural Networks as standalone components and in ensemble formulations. Results on the MNIST dataset show that the proposed modification alleviates standard Rprop's problems demonstrating improved learning speed and accuracy.
no_new_dataset
0.945801