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1605.04369
Ragav Venkatesan
Ragav Venkatesan and Vijetha Gattupalli and Baoxin Li
Neural Dataset Generality
Long version of the paper accepted at IEEE International Conference on Image Processing 2016
null
10.1109/ICIP.2016.7532315
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Often the filters learned by Convolutional Neural Networks (CNNs) from different datasets appear similar. This is prominent in the first few layers. This similarity of filters is being exploited for the purposes of transfer learning and some studies have been made to analyse such transferability of features. This is also being used as an initialization technique for different tasks in the same dataset or for the same task in similar datasets. Off-the-shelf CNN features have capitalized on this idea to promote their networks as best transferable and most general and are used in a cavalier manner in day-to-day computer vision tasks. It is curious that while the filters learned by these CNNs are related to the atomic structures of the images from which they are learnt, all datasets learn similar looking low-level filters. With the understanding that a dataset that contains many such atomic structures learn general filters and are therefore useful to initialize other networks with, we propose a way to analyse and quantify generality among datasets from their accuracies on transferred filters. We applied this metric on several popular character recognition, natural image and a medical image dataset, and arrived at some interesting conclusions. On further experimentation we also discovered that particular classes in a dataset themselves are more general than others.
[ { "version": "v1", "created": "Sat, 14 May 2016 03:17:15 GMT" } ]
2017-05-03T00:00:00
[ [ "Venkatesan", "Ragav", "" ], [ "Gattupalli", "Vijetha", "" ], [ "Li", "Baoxin", "" ] ]
TITLE: Neural Dataset Generality ABSTRACT: Often the filters learned by Convolutional Neural Networks (CNNs) from different datasets appear similar. This is prominent in the first few layers. This similarity of filters is being exploited for the purposes of transfer learning and some studies have been made to analyse such transferability of features. This is also being used as an initialization technique for different tasks in the same dataset or for the same task in similar datasets. Off-the-shelf CNN features have capitalized on this idea to promote their networks as best transferable and most general and are used in a cavalier manner in day-to-day computer vision tasks. It is curious that while the filters learned by these CNNs are related to the atomic structures of the images from which they are learnt, all datasets learn similar looking low-level filters. With the understanding that a dataset that contains many such atomic structures learn general filters and are therefore useful to initialize other networks with, we propose a way to analyse and quantify generality among datasets from their accuracies on transferred filters. We applied this metric on several popular character recognition, natural image and a medical image dataset, and arrived at some interesting conclusions. On further experimentation we also discovered that particular classes in a dataset themselves are more general than others.
no_new_dataset
0.948917
1606.01959
Oscar Fontanelli
Oscar Fontanelli, Pedro Miramontes, Yaning Yang, Germinal Cocho, Wentian Li
Beyond Zipf's Law: The Lavalette Rank Function and its Properties
15 pages, 4 figures
PLoS ONE 11(9), 2016, e0163241
10.1371/journal.pone.0163241
null
physics.data-an physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Although Zipf's law is widespread in natural and social data, one often encounters situations where one or both ends of the ranked data deviate from the power-law function. Previously we proposed the Beta rank function to improve the fitting of data which does not follow a perfect Zipf's law. Here we show that when the two parameters in the Beta rank function have the same value, the Lavalette rank function, the probability density function can be derived analytically. We also show both computationally and analytically that Lavalette distribution is approximately equal, though not identical, to the lognormal distribution. We illustrate the utility of Lavalette rank function in several datasets. We also address three analysis issues on the statistical testing of Lavalette fitting function, comparison between Zipf's law and lognormal distribution through Lavalette function, and comparison between lognormal distribution and Lavalette distribution.
[ { "version": "v1", "created": "Mon, 6 Jun 2016 22:10:57 GMT" } ]
2017-05-03T00:00:00
[ [ "Fontanelli", "Oscar", "" ], [ "Miramontes", "Pedro", "" ], [ "Yang", "Yaning", "" ], [ "Cocho", "Germinal", "" ], [ "Li", "Wentian", "" ] ]
TITLE: Beyond Zipf's Law: The Lavalette Rank Function and its Properties ABSTRACT: Although Zipf's law is widespread in natural and social data, one often encounters situations where one or both ends of the ranked data deviate from the power-law function. Previously we proposed the Beta rank function to improve the fitting of data which does not follow a perfect Zipf's law. Here we show that when the two parameters in the Beta rank function have the same value, the Lavalette rank function, the probability density function can be derived analytically. We also show both computationally and analytically that Lavalette distribution is approximately equal, though not identical, to the lognormal distribution. We illustrate the utility of Lavalette rank function in several datasets. We also address three analysis issues on the statistical testing of Lavalette fitting function, comparison between Zipf's law and lognormal distribution through Lavalette function, and comparison between lognormal distribution and Lavalette distribution.
no_new_dataset
0.953013
1612.00193
Gr\'egoire Ferr\'e
G. Ferr\'e, T. Haut and K. Barros
Learning molecular energies using localized graph kernels
null
The Journal of Chemical Physics, 146(11), 114107 (2017)
10.1063/1.4978623
null
physics.comp-ph cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent machine learning methods make it possible to model potential energy of atomic configurations with chemical-level accuracy (as calculated from ab-initio calculations) and at speeds suitable for molecular dynam- ics simulation. Best performance is achieved when the known physical constraints are encoded in the machine learning models. For example, the atomic energy is invariant under global translations and rotations, it is also invariant to permutations of same-species atoms. Although simple to state, these symmetries are complicated to encode into machine learning algorithms. In this paper, we present a machine learning approach based on graph theory that naturally incorporates translation, rotation, and permutation symmetries. Specifically, we use a random walk graph kernel to measure the similarity of two adjacency matrices, each of which represents a local atomic environment. This Graph Approximated Energy (GRAPE) approach is flexible and admits many possible extensions. We benchmark a simple version of GRAPE by predicting atomization energies on a standard dataset of organic molecules.
[ { "version": "v1", "created": "Thu, 1 Dec 2016 10:23:59 GMT" }, { "version": "v2", "created": "Tue, 25 Apr 2017 10:03:41 GMT" } ]
2017-05-03T00:00:00
[ [ "Ferré", "G.", "" ], [ "Haut", "T.", "" ], [ "Barros", "K.", "" ] ]
TITLE: Learning molecular energies using localized graph kernels ABSTRACT: Recent machine learning methods make it possible to model potential energy of atomic configurations with chemical-level accuracy (as calculated from ab-initio calculations) and at speeds suitable for molecular dynam- ics simulation. Best performance is achieved when the known physical constraints are encoded in the machine learning models. For example, the atomic energy is invariant under global translations and rotations, it is also invariant to permutations of same-species atoms. Although simple to state, these symmetries are complicated to encode into machine learning algorithms. In this paper, we present a machine learning approach based on graph theory that naturally incorporates translation, rotation, and permutation symmetries. Specifically, we use a random walk graph kernel to measure the similarity of two adjacency matrices, each of which represents a local atomic environment. This Graph Approximated Energy (GRAPE) approach is flexible and admits many possible extensions. We benchmark a simple version of GRAPE by predicting atomization energies on a standard dataset of organic molecules.
no_new_dataset
0.945701
1612.04003
Aditya Devarakonda
Aditya Devarakonda, Kimon Fountoulakis, James Demmel, Michael W. Mahoney
Avoiding communication in primal and dual block coordinate descent methods
null
null
null
null
cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Primal and dual block coordinate descent methods are iterative methods for solving regularized and unregularized optimization problems. Distributed-memory parallel implementations of these methods have become popular in analyzing large machine learning datasets. However, existing implementations communicate at every iteration which, on modern data center and supercomputing architectures, often dominates the cost of floating-point computation. Recent results on communication-avoiding Krylov subspace methods suggest that large speedups are possible by re-organizing iterative algorithms to avoid communication. We show how applying similar algorithmic transformations can lead to primal and dual block coordinate descent methods that only communicate every $s$ iterations--where $s$ is a tuning parameter--instead of every iteration for the \textit{regularized least-squares problem}. We show that the communication-avoiding variants reduce the number of synchronizations by a factor of $s$ on distributed-memory parallel machines without altering the convergence rate and attains strong scaling speedups of up to $6.1\times$ on a Cray XC30 supercomputer.
[ { "version": "v1", "created": "Tue, 13 Dec 2016 02:59:33 GMT" }, { "version": "v2", "created": "Tue, 2 May 2017 01:57:40 GMT" } ]
2017-05-03T00:00:00
[ [ "Devarakonda", "Aditya", "" ], [ "Fountoulakis", "Kimon", "" ], [ "Demmel", "James", "" ], [ "Mahoney", "Michael W.", "" ] ]
TITLE: Avoiding communication in primal and dual block coordinate descent methods ABSTRACT: Primal and dual block coordinate descent methods are iterative methods for solving regularized and unregularized optimization problems. Distributed-memory parallel implementations of these methods have become popular in analyzing large machine learning datasets. However, existing implementations communicate at every iteration which, on modern data center and supercomputing architectures, often dominates the cost of floating-point computation. Recent results on communication-avoiding Krylov subspace methods suggest that large speedups are possible by re-organizing iterative algorithms to avoid communication. We show how applying similar algorithmic transformations can lead to primal and dual block coordinate descent methods that only communicate every $s$ iterations--where $s$ is a tuning parameter--instead of every iteration for the \textit{regularized least-squares problem}. We show that the communication-avoiding variants reduce the number of synchronizations by a factor of $s$ on distributed-memory parallel machines without altering the convergence rate and attains strong scaling speedups of up to $6.1\times$ on a Cray XC30 supercomputer.
no_new_dataset
0.942082
1703.01386
Pongsate Tangseng
Pongsate Tangseng, Zhipeng Wu, Kota Yamaguchi
Looking at Outfit to Parse Clothing
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper extends fully-convolutional neural networks (FCN) for the clothing parsing problem. Clothing parsing requires higher-level knowledge on clothing semantics and contextual cues to disambiguate fine-grained categories. We extend FCN architecture with a side-branch network which we refer outfit encoder to predict a consistent set of clothing labels to encourage combinatorial preference, and with conditional random field (CRF) to explicitly consider coherent label assignment to the given image. The empirical results using Fashionista and CFPD datasets show that our model achieves state-of-the-art performance in clothing parsing, without additional supervision during training. We also study the qualitative influence of annotation on the current clothing parsing benchmarks, with our Web-based tool for multi-scale pixel-wise annotation and manual refinement effort to the Fashionista dataset. Finally, we show that the image representation of the outfit encoder is useful for dress-up image retrieval application.
[ { "version": "v1", "created": "Sat, 4 Mar 2017 03:09:36 GMT" } ]
2017-05-03T00:00:00
[ [ "Tangseng", "Pongsate", "" ], [ "Wu", "Zhipeng", "" ], [ "Yamaguchi", "Kota", "" ] ]
TITLE: Looking at Outfit to Parse Clothing ABSTRACT: This paper extends fully-convolutional neural networks (FCN) for the clothing parsing problem. Clothing parsing requires higher-level knowledge on clothing semantics and contextual cues to disambiguate fine-grained categories. We extend FCN architecture with a side-branch network which we refer outfit encoder to predict a consistent set of clothing labels to encourage combinatorial preference, and with conditional random field (CRF) to explicitly consider coherent label assignment to the given image. The empirical results using Fashionista and CFPD datasets show that our model achieves state-of-the-art performance in clothing parsing, without additional supervision during training. We also study the qualitative influence of annotation on the current clothing parsing benchmarks, with our Web-based tool for multi-scale pixel-wise annotation and manual refinement effort to the Fashionista dataset. Finally, we show that the image representation of the outfit encoder is useful for dress-up image retrieval application.
no_new_dataset
0.951504
1704.04684
Luis Argerich
Luis Argerich, Natalia Golmar
Generic LSH Families for the Angular Distance Based on Johnson-Lindenstrauss Projections and Feature Hashing LSH
null
null
null
null
cs.DS cs.AI cs.IR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we propose the creation of generic LSH families for the angular distance based on Johnson-Lindenstrauss projections. We show that feature hashing is a valid J-L projection and propose two new LSH families based on feature hashing. These new LSH families are tested on both synthetic and real datasets with very good results and a considerable performance improvement over other LSH families. While the theoretical analysis is done for the angular distance, these families can also be used in practice for the euclidean distance with excellent results [2]. Our tests using real datasets show that the proposed LSH functions work well for the euclidean distance.
[ { "version": "v1", "created": "Sat, 15 Apr 2017 19:32:51 GMT" } ]
2017-05-03T00:00:00
[ [ "Argerich", "Luis", "" ], [ "Golmar", "Natalia", "" ] ]
TITLE: Generic LSH Families for the Angular Distance Based on Johnson-Lindenstrauss Projections and Feature Hashing LSH ABSTRACT: In this paper we propose the creation of generic LSH families for the angular distance based on Johnson-Lindenstrauss projections. We show that feature hashing is a valid J-L projection and propose two new LSH families based on feature hashing. These new LSH families are tested on both synthetic and real datasets with very good results and a considerable performance improvement over other LSH families. While the theoretical analysis is done for the angular distance, these families can also be used in practice for the euclidean distance with excellent results [2]. Our tests using real datasets show that the proposed LSH functions work well for the euclidean distance.
no_new_dataset
0.958109
1704.07595
Di Xie
Chao Li and Qiaoyong Zhong and Di Xie and Shiliang Pu
Skeleton-based Action Recognition with Convolutional Neural Networks
ICMEW 2017
null
10.1109/LSP.2017.2678539
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Current state-of-the-art approaches to skeleton-based action recognition are mostly based on recurrent neural networks (RNN). In this paper, we propose a novel convolutional neural networks (CNN) based framework for both action classification and detection. Raw skeleton coordinates as well as skeleton motion are fed directly into CNN for label prediction. A novel skeleton transformer module is designed to rearrange and select important skeleton joints automatically. With a simple 7-layer network, we obtain 89.3% accuracy on validation set of the NTU RGB+D dataset. For action detection in untrimmed videos, we develop a window proposal network to extract temporal segment proposals, which are further classified within the same network. On the recent PKU-MMD dataset, we achieve 93.7% mAP, surpassing the baseline by a large margin.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 09:09:00 GMT" } ]
2017-05-03T00:00:00
[ [ "Li", "Chao", "" ], [ "Zhong", "Qiaoyong", "" ], [ "Xie", "Di", "" ], [ "Pu", "Shiliang", "" ] ]
TITLE: Skeleton-based Action Recognition with Convolutional Neural Networks ABSTRACT: Current state-of-the-art approaches to skeleton-based action recognition are mostly based on recurrent neural networks (RNN). In this paper, we propose a novel convolutional neural networks (CNN) based framework for both action classification and detection. Raw skeleton coordinates as well as skeleton motion are fed directly into CNN for label prediction. A novel skeleton transformer module is designed to rearrange and select important skeleton joints automatically. With a simple 7-layer network, we obtain 89.3% accuracy on validation set of the NTU RGB+D dataset. For action detection in untrimmed videos, we develop a window proposal network to extract temporal segment proposals, which are further classified within the same network. On the recent PKU-MMD dataset, we achieve 93.7% mAP, surpassing the baseline by a large margin.
no_new_dataset
0.948775
1705.00648
William Yang Wang
William Yang Wang
"Liar, Liar Pants on Fire": A New Benchmark Dataset for Fake News Detection
ACL 2017
null
null
null
cs.CL cs.CY
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Automatic fake news detection is a challenging problem in deception detection, and it has tremendous real-world political and social impacts. However, statistical approaches to combating fake news has been dramatically limited by the lack of labeled benchmark datasets. In this paper, we present liar: a new, publicly available dataset for fake news detection. We collected a decade-long, 12.8K manually labeled short statements in various contexts from PolitiFact.com, which provides detailed analysis report and links to source documents for each case. This dataset can be used for fact-checking research as well. Notably, this new dataset is an order of magnitude larger than previously largest public fake news datasets of similar type. Empirically, we investigate automatic fake news detection based on surface-level linguistic patterns. We have designed a novel, hybrid convolutional neural network to integrate meta-data with text. We show that this hybrid approach can improve a text-only deep learning model.
[ { "version": "v1", "created": "Mon, 1 May 2017 18:20:47 GMT" } ]
2017-05-03T00:00:00
[ [ "Wang", "William Yang", "" ] ]
TITLE: "Liar, Liar Pants on Fire": A New Benchmark Dataset for Fake News Detection ABSTRACT: Automatic fake news detection is a challenging problem in deception detection, and it has tremendous real-world political and social impacts. However, statistical approaches to combating fake news has been dramatically limited by the lack of labeled benchmark datasets. In this paper, we present liar: a new, publicly available dataset for fake news detection. We collected a decade-long, 12.8K manually labeled short statements in various contexts from PolitiFact.com, which provides detailed analysis report and links to source documents for each case. This dataset can be used for fact-checking research as well. Notably, this new dataset is an order of magnitude larger than previously largest public fake news datasets of similar type. Empirically, we investigate automatic fake news detection based on surface-level linguistic patterns. We have designed a novel, hybrid convolutional neural network to integrate meta-data with text. We show that this hybrid approach can improve a text-only deep learning model.
new_dataset
0.961606
1705.00740
Cheng Li
Bingyu Wang, Cheng Li, Virgil Pavlu, Javed Aslam
Regularizing Model Complexity and Label Structure for Multi-Label Text Classification
null
null
null
null
stat.ML cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multi-label text classification is a popular machine learning task where each document is assigned with multiple relevant labels. This task is challenging due to high dimensional features and correlated labels. Multi-label text classifiers need to be carefully regularized to prevent the severe over-fitting in the high dimensional space, and also need to take into account label dependencies in order to make accurate predictions under uncertainty. We demonstrate significant and practical improvement by carefully regularizing the model complexity during training phase, and also regularizing the label search space during prediction phase. Specifically, we regularize the classifier training using Elastic-net (L1+L2) penalty for reducing model complexity/size, and employ early stopping to prevent overfitting. At prediction time, we apply support inference to restrict the search space to label sets encountered in the training set, and F-optimizer GFM to make optimal predictions for the F1 metric. We show that although support inference only provides density estimations on existing label combinations, when combined with GFM predictor, the algorithm can output unseen label combinations. Taken collectively, our experiments show state of the art results on many benchmark datasets. Beyond performance and practical contributions, we make some interesting observations. Contrary to the prior belief, which deems support inference as purely an approximate inference procedure, we show that support inference acts as a strong regularizer on the label prediction structure. It allows the classifier to take into account label dependencies during prediction even if the classifiers had not modeled any label dependencies during training.
[ { "version": "v1", "created": "Mon, 1 May 2017 23:30:13 GMT" } ]
2017-05-03T00:00:00
[ [ "Wang", "Bingyu", "" ], [ "Li", "Cheng", "" ], [ "Pavlu", "Virgil", "" ], [ "Aslam", "Javed", "" ] ]
TITLE: Regularizing Model Complexity and Label Structure for Multi-Label Text Classification ABSTRACT: Multi-label text classification is a popular machine learning task where each document is assigned with multiple relevant labels. This task is challenging due to high dimensional features and correlated labels. Multi-label text classifiers need to be carefully regularized to prevent the severe over-fitting in the high dimensional space, and also need to take into account label dependencies in order to make accurate predictions under uncertainty. We demonstrate significant and practical improvement by carefully regularizing the model complexity during training phase, and also regularizing the label search space during prediction phase. Specifically, we regularize the classifier training using Elastic-net (L1+L2) penalty for reducing model complexity/size, and employ early stopping to prevent overfitting. At prediction time, we apply support inference to restrict the search space to label sets encountered in the training set, and F-optimizer GFM to make optimal predictions for the F1 metric. We show that although support inference only provides density estimations on existing label combinations, when combined with GFM predictor, the algorithm can output unseen label combinations. Taken collectively, our experiments show state of the art results on many benchmark datasets. Beyond performance and practical contributions, we make some interesting observations. Contrary to the prior belief, which deems support inference as purely an approximate inference procedure, we show that support inference acts as a strong regularizer on the label prediction structure. It allows the classifier to take into account label dependencies during prediction even if the classifiers had not modeled any label dependencies during training.
no_new_dataset
0.947575
1705.00748
Katherine Driggs-Campbell
Katherine Driggs-Campbell, Roy Dong, S. Shankar Sastry, Ruzena Bajcsy
Robust, Informative Human-in-the-Loop Predictions via Empirical Reachable Sets
null
null
null
null
cs.SY
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In order to develop provably safe human-in-the-loop systems, accurate and precise models of human behavior must be developed. In the case of intelligent vehicles, one can imagine the need for predicting driver behavior to develop minimally invasive active safety systems or to safely interact with other vehicles on the road. We present a optimization based method for approximating the stochastic reachable set for human-in-the-loop systems. This method identifies the most precise subset of states that a human driven vehicle may enter, given some dataset of observed trajectories. We phrase this problem as a mixed integer linear program, which can be solved using branch and bound methods. The resulting model uncovers the most representative subset that encapsulates the likely trajectories, up to some probability threshold, by optimally rejecting outliers in the dataset. This tool provides set predictions consisting of trajectories observed from the nonlinear dynamics and behaviors of the human driven car, and can account for modes of behavior, like the driver state or intent. This allows us to predict driving behavior over long time horizons with high accuracy. By using this realistic data and flexible algorithm, a precise and accurate driver model can be developed to capture likely behaviors. The resulting prediction can be tailored to an individual for use in semi-autonomous frameworks or generally applied for autonomous planning in interactive maneuvers.
[ { "version": "v1", "created": "Tue, 2 May 2017 00:32:13 GMT" } ]
2017-05-03T00:00:00
[ [ "Driggs-Campbell", "Katherine", "" ], [ "Dong", "Roy", "" ], [ "Sastry", "S. Shankar", "" ], [ "Bajcsy", "Ruzena", "" ] ]
TITLE: Robust, Informative Human-in-the-Loop Predictions via Empirical Reachable Sets ABSTRACT: In order to develop provably safe human-in-the-loop systems, accurate and precise models of human behavior must be developed. In the case of intelligent vehicles, one can imagine the need for predicting driver behavior to develop minimally invasive active safety systems or to safely interact with other vehicles on the road. We present a optimization based method for approximating the stochastic reachable set for human-in-the-loop systems. This method identifies the most precise subset of states that a human driven vehicle may enter, given some dataset of observed trajectories. We phrase this problem as a mixed integer linear program, which can be solved using branch and bound methods. The resulting model uncovers the most representative subset that encapsulates the likely trajectories, up to some probability threshold, by optimally rejecting outliers in the dataset. This tool provides set predictions consisting of trajectories observed from the nonlinear dynamics and behaviors of the human driven car, and can account for modes of behavior, like the driver state or intent. This allows us to predict driving behavior over long time horizons with high accuracy. By using this realistic data and flexible algorithm, a precise and accurate driver model can be developed to capture likely behaviors. The resulting prediction can be tailored to an individual for use in semi-autonomous frameworks or generally applied for autonomous planning in interactive maneuvers.
no_new_dataset
0.942295
1705.00761
Samir Abdelrahman
Mahmoud Mahdi, Samir Abdelrahman, Reem Bahgat, and Ismail Ismail
F-tree: an algorithm for clustering transactional data using frequency tree
Appeared at Al-Azhar University Engineering Journal, JAUES, Vol.5, No. 8, Dec 2010
null
null
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Clustering is an important data mining technique that groups similar data records, recently categorical transaction clustering is received more attention. In this research, we study the problem of categorical data clustering for transactional data characterized with high dimensionality and large volume. We propose a novel algorithm for clustering transactional data called F-Tree, which is based on the idea of the frequent pattern algorithm FP-tree; the fastest approaches to the frequent item set mining. And the simple idea behind the F-Tree is to generate small high pure clusters, and then merge them. That makes it fast, and dynamic in clustering large transactional datasets with high dimensions. We also present a new solution to solve the overlapping problem between clusters, by defining a new criterion function, which is based on the probability of overlapping between weighted items. Our experimental evaluation on real datasets shows that: Firstly, F-Tree is effective in finding interesting clusters. Secondly, the usage of the tree structure reduces the clustering process time of the large data set with high attributes. Thirdly, the proposed evaluation metric used efficiently to solve the overlapping of transaction items generates high-quality clustering results. Finally, we have concluded that the process of merging pure and small clusters increases the purity of resulted clusters as well as it reduces the time of clustering better than the process of generating clusters directly from dataset then refine clusters.
[ { "version": "v1", "created": "Tue, 2 May 2017 01:55:44 GMT" } ]
2017-05-03T00:00:00
[ [ "Mahdi", "Mahmoud", "" ], [ "Abdelrahman", "Samir", "" ], [ "Bahgat", "Reem", "" ], [ "Ismail", "Ismail", "" ] ]
TITLE: F-tree: an algorithm for clustering transactional data using frequency tree ABSTRACT: Clustering is an important data mining technique that groups similar data records, recently categorical transaction clustering is received more attention. In this research, we study the problem of categorical data clustering for transactional data characterized with high dimensionality and large volume. We propose a novel algorithm for clustering transactional data called F-Tree, which is based on the idea of the frequent pattern algorithm FP-tree; the fastest approaches to the frequent item set mining. And the simple idea behind the F-Tree is to generate small high pure clusters, and then merge them. That makes it fast, and dynamic in clustering large transactional datasets with high dimensions. We also present a new solution to solve the overlapping problem between clusters, by defining a new criterion function, which is based on the probability of overlapping between weighted items. Our experimental evaluation on real datasets shows that: Firstly, F-Tree is effective in finding interesting clusters. Secondly, the usage of the tree structure reduces the clustering process time of the large data set with high attributes. Thirdly, the proposed evaluation metric used efficiently to solve the overlapping of transaction items generates high-quality clustering results. Finally, we have concluded that the process of merging pure and small clusters increases the purity of resulted clusters as well as it reduces the time of clustering better than the process of generating clusters directly from dataset then refine clusters.
no_new_dataset
0.955858
1705.00771
Yehui Yang
Yehui Yang, Tao Li, Wensi Li, Haishan Wu, Wei Fan, Wensheng Zhang
Lesion detection and Grading of Diabetic Retinopathy via Two-stages Deep Convolutional Neural Networks
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose an automatic diabetic retinopathy (DR) analysis algorithm based on two-stages deep convolutional neural networks (DCNN). Compared to existing DCNN-based DR detection methods, the proposed algorithm have the following advantages: (1) Our method can point out the location and type of lesions in the fundus images, as well as giving the severity grades of DR. Moreover, since retina lesions and DR severity appear with different scales in fundus images, the integration of both local and global networks learn more complete and specific features for DR analysis. (2) By introducing imbalanced weighting map, more attentions will be given to lesion patches for DR grading, which significantly improve the performance of the proposed algorithm. In this study, we label 12,206 lesion patches and re-annotate the DR grades of 23,595 fundus images from Kaggle competition dataset. Under the guidance of clinical ophthalmologists, the experimental results show that our local lesion detection net achieve comparable performance with trained human observers, and the proposed imbalanced weighted scheme also be proved to significantly improve the capability of our DCNN-based DR grading algorithm.
[ { "version": "v1", "created": "Tue, 2 May 2017 02:44:39 GMT" } ]
2017-05-03T00:00:00
[ [ "Yang", "Yehui", "" ], [ "Li", "Tao", "" ], [ "Li", "Wensi", "" ], [ "Wu", "Haishan", "" ], [ "Fan", "Wei", "" ], [ "Zhang", "Wensheng", "" ] ]
TITLE: Lesion detection and Grading of Diabetic Retinopathy via Two-stages Deep Convolutional Neural Networks ABSTRACT: We propose an automatic diabetic retinopathy (DR) analysis algorithm based on two-stages deep convolutional neural networks (DCNN). Compared to existing DCNN-based DR detection methods, the proposed algorithm have the following advantages: (1) Our method can point out the location and type of lesions in the fundus images, as well as giving the severity grades of DR. Moreover, since retina lesions and DR severity appear with different scales in fundus images, the integration of both local and global networks learn more complete and specific features for DR analysis. (2) By introducing imbalanced weighting map, more attentions will be given to lesion patches for DR grading, which significantly improve the performance of the proposed algorithm. In this study, we label 12,206 lesion patches and re-annotate the DR grades of 23,595 fundus images from Kaggle competition dataset. Under the guidance of clinical ophthalmologists, the experimental results show that our local lesion detection net achieve comparable performance with trained human observers, and the proposed imbalanced weighted scheme also be proved to significantly improve the capability of our DCNN-based DR grading algorithm.
no_new_dataset
0.950869
1705.00797
Konstantin Bauman
Evgeny Bauman and Konstantin Bauman
One-Class Semi-Supervised Learning: Detecting Linearly Separable Class by its Mean
null
null
null
null
stat.ML cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we presented a novel semi-supervised one-class classification algorithm which assumes that class is linearly separable from other elements. We proved theoretically that class is linearly separable if and only if it is maximal by probability within the sets with the same mean. Furthermore, we presented an algorithm for identifying such linearly separable class utilizing linear programming. We described three application cases including an assumption of linear separability, Gaussian distribution, and the case of linear separability in transformed space of kernel functions. Finally, we demonstrated the work of the proposed algorithm on the USPS dataset and analyzed the relationship of the performance of the algorithm and the size of the initially labeled sample.
[ { "version": "v1", "created": "Tue, 2 May 2017 05:00:28 GMT" } ]
2017-05-03T00:00:00
[ [ "Bauman", "Evgeny", "" ], [ "Bauman", "Konstantin", "" ] ]
TITLE: One-Class Semi-Supervised Learning: Detecting Linearly Separable Class by its Mean ABSTRACT: In this paper, we presented a novel semi-supervised one-class classification algorithm which assumes that class is linearly separable from other elements. We proved theoretically that class is linearly separable if and only if it is maximal by probability within the sets with the same mean. Furthermore, we presented an algorithm for identifying such linearly separable class utilizing linear programming. We described three application cases including an assumption of linear separability, Gaussian distribution, and the case of linear separability in transformed space of kernel functions. Finally, we demonstrated the work of the proposed algorithm on the USPS dataset and analyzed the relationship of the performance of the algorithm and the size of the initially labeled sample.
no_new_dataset
0.952838
1705.00823
Yuya Yoshikawa
Yuya Yoshikawa, Yutaro Shigeto, Akikazu Takeuchi
STAIR Captions: Constructing a Large-Scale Japanese Image Caption Dataset
Accepted as ACL2017 short paper. 5 pages
null
null
null
cs.CL cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In recent years, automatic generation of image descriptions (captions), that is, image captioning, has attracted a great deal of attention. In this paper, we particularly consider generating Japanese captions for images. Since most available caption datasets have been constructed for English language, there are few datasets for Japanese. To tackle this problem, we construct a large-scale Japanese image caption dataset based on images from MS-COCO, which is called STAIR Captions. STAIR Captions consists of 820,310 Japanese captions for 164,062 images. In the experiment, we show that a neural network trained using STAIR Captions can generate more natural and better Japanese captions, compared to those generated using English-Japanese machine translation after generating English captions.
[ { "version": "v1", "created": "Tue, 2 May 2017 07:07:55 GMT" } ]
2017-05-03T00:00:00
[ [ "Yoshikawa", "Yuya", "" ], [ "Shigeto", "Yutaro", "" ], [ "Takeuchi", "Akikazu", "" ] ]
TITLE: STAIR Captions: Constructing a Large-Scale Japanese Image Caption Dataset ABSTRACT: In recent years, automatic generation of image descriptions (captions), that is, image captioning, has attracted a great deal of attention. In this paper, we particularly consider generating Japanese captions for images. Since most available caption datasets have been constructed for English language, there are few datasets for Japanese. To tackle this problem, we construct a large-scale Japanese image caption dataset based on images from MS-COCO, which is called STAIR Captions. STAIR Captions consists of 820,310 Japanese captions for 164,062 images. In the experiment, we show that a neural network trained using STAIR Captions can generate more natural and better Japanese captions, compared to those generated using English-Japanese machine translation after generating English captions.
new_dataset
0.957158
1705.00825
Xiaokai Wei
Xiaokai Wei, Bokai Cao and Philip S. Yu
Multi-view Unsupervised Feature Selection by Cross-diffused Matrix Alignment
8 pages
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multi-view high-dimensional data become increasingly popular in the big data era. Feature selection is a useful technique for alleviating the curse of dimensionality in multi-view learning. In this paper, we study unsupervised feature selection for multi-view data, as class labels are usually expensive to obtain. Traditional feature selection methods are mostly designed for single-view data and cannot fully exploit the rich information from multi-view data. Existing multi-view feature selection methods are usually based on noisy cluster labels which might not preserve sufficient information from multi-view data. To better utilize multi-view information, we propose a method, CDMA-FS, to select features for each view by performing alignment on a cross diffused matrix. We formulate it as a constrained optimization problem and solve it using Quasi-Newton based method. Experiments results on four real-world datasets show that the proposed method is more effective than the state-of-the-art methods in multi-view setting.
[ { "version": "v1", "created": "Tue, 2 May 2017 07:12:59 GMT" } ]
2017-05-03T00:00:00
[ [ "Wei", "Xiaokai", "" ], [ "Cao", "Bokai", "" ], [ "Yu", "Philip S.", "" ] ]
TITLE: Multi-view Unsupervised Feature Selection by Cross-diffused Matrix Alignment ABSTRACT: Multi-view high-dimensional data become increasingly popular in the big data era. Feature selection is a useful technique for alleviating the curse of dimensionality in multi-view learning. In this paper, we study unsupervised feature selection for multi-view data, as class labels are usually expensive to obtain. Traditional feature selection methods are mostly designed for single-view data and cannot fully exploit the rich information from multi-view data. Existing multi-view feature selection methods are usually based on noisy cluster labels which might not preserve sufficient information from multi-view data. To better utilize multi-view information, we propose a method, CDMA-FS, to select features for each view by performing alignment on a cross diffused matrix. We formulate it as a constrained optimization problem and solve it using Quasi-Newton based method. Experiments results on four real-world datasets show that the proposed method is more effective than the state-of-the-art methods in multi-view setting.
no_new_dataset
0.948106
1705.00835
Pichao Wang
Zewei Ding and Pichao Wang and Philip O. Ogunbona and Wanqing Li
Investigation of Different Skeleton Features for CNN-based 3D Action Recognition
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deep learning techniques are being used in skeleton based action recognition tasks and outstanding performance has been reported. Compared with RNN based methods which tend to overemphasize temporal information, CNN-based approaches can jointly capture spatio-temporal information from texture color images encoded from skeleton sequences. There are several skeleton-based features that have proven effective in RNN-based and handcrafted-feature-based methods. However, it remains unknown whether they are suitable for CNN-based approaches. This paper proposes to encode five spatial skeleton features into images with different encoding methods. In addition, the performance implication of different joints used for feature extraction is studied. The proposed method achieved state-of-the-art performance on NTU RGB+D dataset for 3D human action analysis. An accuracy of 75.32\% was achieved in Large Scale 3D Human Activity Analysis Challenge in Depth Videos.
[ { "version": "v1", "created": "Tue, 2 May 2017 07:42:35 GMT" } ]
2017-05-03T00:00:00
[ [ "Ding", "Zewei", "" ], [ "Wang", "Pichao", "" ], [ "Ogunbona", "Philip O.", "" ], [ "Li", "Wanqing", "" ] ]
TITLE: Investigation of Different Skeleton Features for CNN-based 3D Action Recognition ABSTRACT: Deep learning techniques are being used in skeleton based action recognition tasks and outstanding performance has been reported. Compared with RNN based methods which tend to overemphasize temporal information, CNN-based approaches can jointly capture spatio-temporal information from texture color images encoded from skeleton sequences. There are several skeleton-based features that have proven effective in RNN-based and handcrafted-feature-based methods. However, it remains unknown whether they are suitable for CNN-based approaches. This paper proposes to encode five spatial skeleton features into images with different encoding methods. In addition, the performance implication of different joints used for feature extraction is studied. The proposed method achieved state-of-the-art performance on NTU RGB+D dataset for 3D human action analysis. An accuracy of 75.32\% was achieved in Large Scale 3D Human Activity Analysis Challenge in Depth Videos.
no_new_dataset
0.94801
1705.00873
Zhiyuan Shi
Zhiyuan Shi, Parthipan Siva, Tao Xiang
Transfer Learning by Ranking for Weakly Supervised Object Annotation
BMVC 2012
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Most existing approaches to training object detectors rely on fully supervised learning, which requires the tedious manual annotation of object location in a training set. Recently there has been an increasing interest in developing weakly supervised approach to detector training where the object location is not manually annotated but automatically determined based on binary (weak) labels indicating if a training image contains the object. This is a challenging problem because each image can contain many candidate object locations which partially overlaps the object of interest. Existing approaches focus on how to best utilise the binary labels for object location annotation. In this paper we propose to solve this problem from a very different perspective by casting it as a transfer learning problem. Specifically, we formulate a novel transfer learning based on learning to rank, which effectively transfers a model for automatic annotation of object location from an auxiliary dataset to a target dataset with completely unrelated object categories. We show that our approach outperforms existing state-of-the-art weakly supervised approach to annotating objects in the challenging VOC dataset.
[ { "version": "v1", "created": "Tue, 2 May 2017 09:23:27 GMT" } ]
2017-05-03T00:00:00
[ [ "Shi", "Zhiyuan", "" ], [ "Siva", "Parthipan", "" ], [ "Xiang", "Tao", "" ] ]
TITLE: Transfer Learning by Ranking for Weakly Supervised Object Annotation ABSTRACT: Most existing approaches to training object detectors rely on fully supervised learning, which requires the tedious manual annotation of object location in a training set. Recently there has been an increasing interest in developing weakly supervised approach to detector training where the object location is not manually annotated but automatically determined based on binary (weak) labels indicating if a training image contains the object. This is a challenging problem because each image can contain many candidate object locations which partially overlaps the object of interest. Existing approaches focus on how to best utilise the binary labels for object location annotation. In this paper we propose to solve this problem from a very different perspective by casting it as a transfer learning problem. Specifically, we formulate a novel transfer learning based on learning to rank, which effectively transfers a model for automatic annotation of object location from an auxiliary dataset to a target dataset with completely unrelated object categories. We show that our approach outperforms existing state-of-the-art weakly supervised approach to annotating objects in the challenging VOC dataset.
no_new_dataset
0.947186
1705.00894
Svitlana Vakulenko
Sebastian Neumaier, Vadim Savenkov and Svitlana Vakulenko
Talking Open Data
Accepted at ESWC2017 demo track
null
null
null
cs.IR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Enticing users into exploring Open Data remains an important challenge for the whole Open Data paradigm. Standard stock interfaces often used by Open Data portals are anything but inspiring even for tech-savvy users, let alone those without an articulated interest in data science. To address a broader range of citizens, we designed an open data search interface supporting natural language interactions via popular platforms like Facebook and Skype. Our data-aware chatbot answers search requests and suggests relevant open datasets, bringing fun factor and a potential of viral dissemination into Open Data exploration. The current system prototype is available for Facebook (https://m.me/OpenDataAssistant) and Skype (https://join.skype.com/bot/6db830ca-b365-44c4-9f4d-d423f728e741) users.
[ { "version": "v1", "created": "Tue, 2 May 2017 10:35:12 GMT" } ]
2017-05-03T00:00:00
[ [ "Neumaier", "Sebastian", "" ], [ "Savenkov", "Vadim", "" ], [ "Vakulenko", "Svitlana", "" ] ]
TITLE: Talking Open Data ABSTRACT: Enticing users into exploring Open Data remains an important challenge for the whole Open Data paradigm. Standard stock interfaces often used by Open Data portals are anything but inspiring even for tech-savvy users, let alone those without an articulated interest in data science. To address a broader range of citizens, we designed an open data search interface supporting natural language interactions via popular platforms like Facebook and Skype. Our data-aware chatbot answers search requests and suggests relevant open datasets, bringing fun factor and a potential of viral dissemination into Open Data exploration. The current system prototype is available for Facebook (https://m.me/OpenDataAssistant) and Skype (https://join.skype.com/bot/6db830ca-b365-44c4-9f4d-d423f728e741) users.
no_new_dataset
0.862004
1705.00949
Christian Mostegel
Christian Mostegel and Rudolf Prettenthaler and Friedrich Fraundorfer and Horst Bischof
Scalable Surface Reconstruction from Point Clouds with Extreme Scale and Density Diversity
This paper was accepted to the IEEE Conference on Computer Vision and Pattern Recognition (CVPR), 2017. The copyright was transfered to IEEE (ieee.org). The official version of the paper will be made available on IEEE Xplore (R) (ieeexplore.ieee.org). This version of the paper also contains the supplementary material, which will not appear IEEE Xplore (R)
null
null
null
cs.CV cs.GR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we present a scalable approach for robustly computing a 3D surface mesh from multi-scale multi-view stereo point clouds that can handle extreme jumps of point density (in our experiments three orders of magnitude). The backbone of our approach is a combination of octree data partitioning, local Delaunay tetrahedralization and graph cut optimization. Graph cut optimization is used twice, once to extract surface hypotheses from local Delaunay tetrahedralizations and once to merge overlapping surface hypotheses even when the local tetrahedralizations do not share the same topology.This formulation allows us to obtain a constant memory consumption per sub-problem while at the same time retaining the density independent interpolation properties of the Delaunay-based optimization. On multiple public datasets, we demonstrate that our approach is highly competitive with the state-of-the-art in terms of accuracy, completeness and outlier resilience. Further, we demonstrate the multi-scale potential of our approach by processing a newly recorded dataset with 2 billion points and a point density variation of more than four orders of magnitude - requiring less than 9GB of RAM per process.
[ { "version": "v1", "created": "Tue, 2 May 2017 13:13:47 GMT" } ]
2017-05-03T00:00:00
[ [ "Mostegel", "Christian", "" ], [ "Prettenthaler", "Rudolf", "" ], [ "Fraundorfer", "Friedrich", "" ], [ "Bischof", "Horst", "" ] ]
TITLE: Scalable Surface Reconstruction from Point Clouds with Extreme Scale and Density Diversity ABSTRACT: In this paper we present a scalable approach for robustly computing a 3D surface mesh from multi-scale multi-view stereo point clouds that can handle extreme jumps of point density (in our experiments three orders of magnitude). The backbone of our approach is a combination of octree data partitioning, local Delaunay tetrahedralization and graph cut optimization. Graph cut optimization is used twice, once to extract surface hypotheses from local Delaunay tetrahedralizations and once to merge overlapping surface hypotheses even when the local tetrahedralizations do not share the same topology.This formulation allows us to obtain a constant memory consumption per sub-problem while at the same time retaining the density independent interpolation properties of the Delaunay-based optimization. On multiple public datasets, we demonstrate that our approach is highly competitive with the state-of-the-art in terms of accuracy, completeness and outlier resilience. Further, we demonstrate the multi-scale potential of our approach by processing a newly recorded dataset with 2 billion points and a point density variation of more than four orders of magnitude - requiring less than 9GB of RAM per process.
new_dataset
0.960025
1705.01089
Sandipan Sikdar
Sandipan Sikdar, Matteo Marsili, Niloy Ganguly, Animesh Mukherjee
Influence of Reviewer Interaction Network on Long-term Citations: A Case Study of the Scientific Peer-Review System of the Journal of High Energy Physics
null
null
null
null
cs.DL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A `peer-review system' in the context of judging research contributions, is one of the prime steps undertaken to ensure the quality of the submissions received, a significant portion of the publishing budget is spent towards successful completion of the peer-review by the publication houses. Nevertheless, the scientific community is largely reaching a consensus that peer-review system, although indispensable, is nonetheless flawed. A very pertinent question therefore is "could this system be improved?". In this paper, we attempt to present an answer to this question by considering a massive dataset of around $29k$ papers with roughly $70k$ distinct review reports together consisting of $12m$ lines of review text from the Journal of High Energy Physics (JHEP) between 1997 and 2015. In specific, we introduce a novel \textit{reviewer-reviewer interaction network} (an edge exists between two reviewers if they were assigned by the same editor) and show that surprisingly the simple structural properties of this network such as degree, clustering coefficient, centrality (closeness, betweenness etc.) serve as strong predictors of the long-term citations (i.e., the overall scientific impact) of a submitted paper. These features, when plugged in a regression model, alone achieves a high $R^2$ of \0.79 and a low $RMSE$ of 0.496 in predicting the long-term citations. In addition, we also design a set of supporting features built from the basic characteristics of the submitted papers, the authors and the referees (e.g., the popularity of the submitting author, the acceptance rate history of a referee, the linguistic properties laden in the text of the review reports etc.), which further results in overall improvement with $R^2$ of 0.81 and $RMSE$ of 0.46.
[ { "version": "v1", "created": "Tue, 2 May 2017 17:47:45 GMT" } ]
2017-05-03T00:00:00
[ [ "Sikdar", "Sandipan", "" ], [ "Marsili", "Matteo", "" ], [ "Ganguly", "Niloy", "" ], [ "Mukherjee", "Animesh", "" ] ]
TITLE: Influence of Reviewer Interaction Network on Long-term Citations: A Case Study of the Scientific Peer-Review System of the Journal of High Energy Physics ABSTRACT: A `peer-review system' in the context of judging research contributions, is one of the prime steps undertaken to ensure the quality of the submissions received, a significant portion of the publishing budget is spent towards successful completion of the peer-review by the publication houses. Nevertheless, the scientific community is largely reaching a consensus that peer-review system, although indispensable, is nonetheless flawed. A very pertinent question therefore is "could this system be improved?". In this paper, we attempt to present an answer to this question by considering a massive dataset of around $29k$ papers with roughly $70k$ distinct review reports together consisting of $12m$ lines of review text from the Journal of High Energy Physics (JHEP) between 1997 and 2015. In specific, we introduce a novel \textit{reviewer-reviewer interaction network} (an edge exists between two reviewers if they were assigned by the same editor) and show that surprisingly the simple structural properties of this network such as degree, clustering coefficient, centrality (closeness, betweenness etc.) serve as strong predictors of the long-term citations (i.e., the overall scientific impact) of a submitted paper. These features, when plugged in a regression model, alone achieves a high $R^2$ of \0.79 and a low $RMSE$ of 0.496 in predicting the long-term citations. In addition, we also design a set of supporting features built from the basic characteristics of the submitted papers, the authors and the referees (e.g., the popularity of the submitting author, the acceptance rate history of a referee, the linguistic properties laden in the text of the review reports etc.), which further results in overall improvement with $R^2$ of 0.81 and $RMSE$ of 0.46.
no_new_dataset
0.939025
1408.2803
Jayadeva
Jayadeva
Learning a hyperplane classifier by minimizing an exact bound on the VC dimension
Accepted Author Manuscript (Neurocomputing, Elsevier); 10 pages
Neurocomputing, Volume 149, Part B, 3 February 2015, Pages 683-689, ISSN 0925-2312,
10.1016/j.neucom.2014.07.062
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The VC dimension measures the capacity of a learning machine, and a low VC dimension leads to good generalization. While SVMs produce state-of-the-art learning performance, it is well known that the VC dimension of a SVM can be unbounded; despite good results in practice, there is no guarantee of good generalization. In this paper, we show how to learn a hyperplane classifier by minimizing an exact, or \boldmath{$\Theta$} bound on its VC dimension. The proposed approach, termed as the Minimal Complexity Machine (MCM), involves solving a simple linear programming problem. Experimental results show, that on a number of benchmark datasets, the proposed approach learns classifiers with error rates much less than conventional SVMs, while often using fewer support vectors. On many benchmark datasets, the number of support vectors is less than one-tenth the number used by SVMs, indicating that the MCM does indeed learn simpler representations.
[ { "version": "v1", "created": "Tue, 12 Aug 2014 18:57:48 GMT" }, { "version": "v2", "created": "Wed, 13 Aug 2014 16:32:30 GMT" } ]
2017-05-02T00:00:00
[ [ "Jayadeva", "", "" ] ]
TITLE: Learning a hyperplane classifier by minimizing an exact bound on the VC dimension ABSTRACT: The VC dimension measures the capacity of a learning machine, and a low VC dimension leads to good generalization. While SVMs produce state-of-the-art learning performance, it is well known that the VC dimension of a SVM can be unbounded; despite good results in practice, there is no guarantee of good generalization. In this paper, we show how to learn a hyperplane classifier by minimizing an exact, or \boldmath{$\Theta$} bound on its VC dimension. The proposed approach, termed as the Minimal Complexity Machine (MCM), involves solving a simple linear programming problem. Experimental results show, that on a number of benchmark datasets, the proposed approach learns classifiers with error rates much less than conventional SVMs, while often using fewer support vectors. On many benchmark datasets, the number of support vectors is less than one-tenth the number used by SVMs, indicating that the MCM does indeed learn simpler representations.
no_new_dataset
0.95297
1410.4573
Jayadeva
Jayadeva, Suresh Chandra, Siddarth Sabharwal, and Sanjit S. Batra
Learning a hyperplane regressor by minimizing an exact bound on the VC dimension
see http://www.sciencedirect.com/science/article/pii/S0925231214010194 or arXiv:1408.2803 for background information
Neurocomputing, Volume 171, 1 January 2016, Pages 1610-1616, ISSN 0925-2312
10.1016/j.neucom.2015.06.065
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The capacity of a learning machine is measured by its Vapnik-Chervonenkis dimension, and learning machines with a low VC dimension generalize better. It is well known that the VC dimension of SVMs can be very large or unbounded, even though they generally yield state-of-the-art learning performance. In this paper, we show how to learn a hyperplane regressor by minimizing an exact, or \boldmath{$\Theta$} bound on its VC dimension. The proposed approach, termed as the Minimal Complexity Machine (MCM) Regressor, involves solving a simple linear programming problem. Experimental results show, that on a number of benchmark datasets, the proposed approach yields regressors with error rates much less than those obtained with conventional SVM regresssors, while often using fewer support vectors. On some benchmark datasets, the number of support vectors is less than one tenth the number used by SVMs, indicating that the MCM does indeed learn simpler representations.
[ { "version": "v1", "created": "Thu, 16 Oct 2014 20:04:49 GMT" } ]
2017-05-02T00:00:00
[ [ "Jayadeva", "", "" ], [ "Chandra", "Suresh", "" ], [ "Sabharwal", "Siddarth", "" ], [ "Batra", "Sanjit S.", "" ] ]
TITLE: Learning a hyperplane regressor by minimizing an exact bound on the VC dimension ABSTRACT: The capacity of a learning machine is measured by its Vapnik-Chervonenkis dimension, and learning machines with a low VC dimension generalize better. It is well known that the VC dimension of SVMs can be very large or unbounded, even though they generally yield state-of-the-art learning performance. In this paper, we show how to learn a hyperplane regressor by minimizing an exact, or \boldmath{$\Theta$} bound on its VC dimension. The proposed approach, termed as the Minimal Complexity Machine (MCM) Regressor, involves solving a simple linear programming problem. Experimental results show, that on a number of benchmark datasets, the proposed approach yields regressors with error rates much less than those obtained with conventional SVM regresssors, while often using fewer support vectors. On some benchmark datasets, the number of support vectors is less than one tenth the number used by SVMs, indicating that the MCM does indeed learn simpler representations.
no_new_dataset
0.952926
1608.03462
Muhammet Bastan
Muhammet Bastan and Ozgur Yilmaz
Multi-View Product Image Search Using Deep ConvNets Representations
13 pages, 16 figures
null
null
null
cs.CV cs.MM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multi-view product image queries can improve retrieval performance over single view queries significantly. In this paper, we investigated the performance of deep convolutional neural networks (ConvNets) on multi-view product image search. First, we trained a VGG-like network to learn deep ConvNets representations of product images. Then, we computed the deep ConvNets representations of database and query images and performed single view queries, and multi-view queries using several early and late fusion approaches. We performed extensive experiments on the publicly available Multi-View Object Image Dataset (MVOD 5K) with both clean background queries from the Internet and cluttered background queries from a mobile phone. We compared the performance of ConvNets to the classical bag-of-visual-words (BoWs). We concluded that (1) multi-view queries with deep ConvNets representations perform significantly better than single view queries, (2) ConvNets perform much better than BoWs and have room for further improvement, (3) pre-training of ConvNets on a different image dataset with background clutter is needed to obtain good performance on cluttered product image queries obtained with a mobile phone.
[ { "version": "v1", "created": "Thu, 11 Aug 2016 13:50:07 GMT" }, { "version": "v2", "created": "Mon, 1 May 2017 08:08:28 GMT" } ]
2017-05-02T00:00:00
[ [ "Bastan", "Muhammet", "" ], [ "Yilmaz", "Ozgur", "" ] ]
TITLE: Multi-View Product Image Search Using Deep ConvNets Representations ABSTRACT: Multi-view product image queries can improve retrieval performance over single view queries significantly. In this paper, we investigated the performance of deep convolutional neural networks (ConvNets) on multi-view product image search. First, we trained a VGG-like network to learn deep ConvNets representations of product images. Then, we computed the deep ConvNets representations of database and query images and performed single view queries, and multi-view queries using several early and late fusion approaches. We performed extensive experiments on the publicly available Multi-View Object Image Dataset (MVOD 5K) with both clean background queries from the Internet and cluttered background queries from a mobile phone. We compared the performance of ConvNets to the classical bag-of-visual-words (BoWs). We concluded that (1) multi-view queries with deep ConvNets representations perform significantly better than single view queries, (2) ConvNets perform much better than BoWs and have room for further improvement, (3) pre-training of ConvNets on a different image dataset with background clutter is needed to obtain good performance on cluttered product image queries obtained with a mobile phone.
no_new_dataset
0.940898
1702.02212
Tarek Sakakini
Tarek Sakakini, Suma Bhat, Pramod Viswanath
MORSE: Semantic-ally Drive-n MORpheme SEgment-er
null
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present in this paper a novel framework for morpheme segmentation which uses the morpho-syntactic regularities preserved by word representations, in addition to orthographic features, to segment words into morphemes. This framework is the first to consider vocabulary-wide syntactico-semantic information for this task. We also analyze the deficiencies of available benchmarking datasets and introduce our own dataset that was created on the basis of compositionality. We validate our algorithm across datasets and present state-of-the-art results.
[ { "version": "v1", "created": "Tue, 7 Feb 2017 21:49:13 GMT" }, { "version": "v2", "created": "Sat, 11 Feb 2017 00:13:28 GMT" }, { "version": "v3", "created": "Mon, 1 May 2017 12:36:34 GMT" } ]
2017-05-02T00:00:00
[ [ "Sakakini", "Tarek", "" ], [ "Bhat", "Suma", "" ], [ "Viswanath", "Pramod", "" ] ]
TITLE: MORSE: Semantic-ally Drive-n MORpheme SEgment-er ABSTRACT: We present in this paper a novel framework for morpheme segmentation which uses the morpho-syntactic regularities preserved by word representations, in addition to orthographic features, to segment words into morphemes. This framework is the first to consider vocabulary-wide syntactico-semantic information for this task. We also analyze the deficiencies of available benchmarking datasets and introduce our own dataset that was created on the basis of compositionality. We validate our algorithm across datasets and present state-of-the-art results.
new_dataset
0.951504
1704.06020
Xun Yang
Xun Yang, Meng Wang, Richang Hong, Qi Tian, Yong Rui
Enhancing Person Re-identification in a Self-trained Subspace
Accepted by ACM Transactions on Multimedia Computing, Communications, and Applications (TOMM)
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Despite the promising progress made in recent years, person re-identification (re-ID) remains a challenging task due to the complex variations in human appearances from different camera views. For this challenging problem, a large variety of algorithms have been developed in the fully-supervised setting, requiring access to a large amount of labeled training data. However, the main bottleneck for fully-supervised re-ID is the limited availability of labeled training samples. To address this problem, in this paper, we propose a self-trained subspace learning paradigm for person re-ID which effectively utilizes both labeled and unlabeled data to learn a discriminative subspace where person images across disjoint camera views can be easily matched. The proposed approach first constructs pseudo pairwise relationships among unlabeled persons using the k-nearest neighbors algorithm. Then, with the pseudo pairwise relationships, the unlabeled samples can be easily combined with the labeled samples to learn a discriminative projection by solving an eigenvalue problem. In addition, we refine the pseudo pairwise relationships iteratively, which further improves the learning performance. A multi-kernel embedding strategy is also incorporated into the proposed approach to cope with the non-linearity in person's appearance and explore the complementation of multiple kernels. In this way, the performance of person re-ID can be greatly enhanced when training data are insufficient. Experimental results on six widely-used datasets demonstrate the effectiveness of our approach and its performance can be comparable to the reported results of most state-of-the-art fully-supervised methods while using much fewer labeled data.
[ { "version": "v1", "created": "Thu, 20 Apr 2017 05:43:05 GMT" }, { "version": "v2", "created": "Sun, 30 Apr 2017 00:28:52 GMT" } ]
2017-05-02T00:00:00
[ [ "Yang", "Xun", "" ], [ "Wang", "Meng", "" ], [ "Hong", "Richang", "" ], [ "Tian", "Qi", "" ], [ "Rui", "Yong", "" ] ]
TITLE: Enhancing Person Re-identification in a Self-trained Subspace ABSTRACT: Despite the promising progress made in recent years, person re-identification (re-ID) remains a challenging task due to the complex variations in human appearances from different camera views. For this challenging problem, a large variety of algorithms have been developed in the fully-supervised setting, requiring access to a large amount of labeled training data. However, the main bottleneck for fully-supervised re-ID is the limited availability of labeled training samples. To address this problem, in this paper, we propose a self-trained subspace learning paradigm for person re-ID which effectively utilizes both labeled and unlabeled data to learn a discriminative subspace where person images across disjoint camera views can be easily matched. The proposed approach first constructs pseudo pairwise relationships among unlabeled persons using the k-nearest neighbors algorithm. Then, with the pseudo pairwise relationships, the unlabeled samples can be easily combined with the labeled samples to learn a discriminative projection by solving an eigenvalue problem. In addition, we refine the pseudo pairwise relationships iteratively, which further improves the learning performance. A multi-kernel embedding strategy is also incorporated into the proposed approach to cope with the non-linearity in person's appearance and explore the complementation of multiple kernels. In this way, the performance of person re-ID can be greatly enhanced when training data are insufficient. Experimental results on six widely-used datasets demonstrate the effectiveness of our approach and its performance can be comparable to the reported results of most state-of-the-art fully-supervised methods while using much fewer labeled data.
no_new_dataset
0.949623
1704.07028
Yuan Li
Jie Xue, Yuan Li, Ravi Janardan
On the expected diameter, width, and complexity of a stochastic convex-hull
null
null
null
null
cs.CG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We investigate several computational problems related to the stochastic convex hull (SCH). Given a stochastic dataset consisting of $n$ points in $\mathbb{R}^d$ each of which has an existence probability, a SCH refers to the convex hull of a realization of the dataset, i.e., a random sample including each point with its existence probability. We are interested in computing certain expected statistics of a SCH, including diameter, width, and combinatorial complexity. For diameter, we establish the first deterministic 1.633-approximation algorithm with a time complexity polynomial in both $n$ and $d$. For width, two approximation algorithms are provided: a deterministic $O(1)$-approximation running in $O(n^{d+1} \log n)$ time, and a fully polynomial-time randomized approximation scheme (FPRAS). For combinatorial complexity, we propose an exact $O(n^d)$-time algorithm. Our solutions exploit many geometric insights in Euclidean space, some of which might be of independent interest.
[ { "version": "v1", "created": "Mon, 24 Apr 2017 03:33:24 GMT" }, { "version": "v2", "created": "Mon, 1 May 2017 05:36:14 GMT" } ]
2017-05-02T00:00:00
[ [ "Xue", "Jie", "" ], [ "Li", "Yuan", "" ], [ "Janardan", "Ravi", "" ] ]
TITLE: On the expected diameter, width, and complexity of a stochastic convex-hull ABSTRACT: We investigate several computational problems related to the stochastic convex hull (SCH). Given a stochastic dataset consisting of $n$ points in $\mathbb{R}^d$ each of which has an existence probability, a SCH refers to the convex hull of a realization of the dataset, i.e., a random sample including each point with its existence probability. We are interested in computing certain expected statistics of a SCH, including diameter, width, and combinatorial complexity. For diameter, we establish the first deterministic 1.633-approximation algorithm with a time complexity polynomial in both $n$ and $d$. For width, two approximation algorithms are provided: a deterministic $O(1)$-approximation running in $O(n^{d+1} \log n)$ time, and a fully polynomial-time randomized approximation scheme (FPRAS). For combinatorial complexity, we propose an exact $O(n^d)$-time algorithm. Our solutions exploit many geometric insights in Euclidean space, some of which might be of independent interest.
no_new_dataset
0.944382
1704.07502
Yongliang Chen
Yongliang Chen
A Labeling-Free Approach to Supervising Deep Neural Networks for Retinal Blood Vessel Segmentation
10 pages, 8 figures, 3 tables, forbidden work, correct the citation typo of [29]
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Segmenting blood vessels in fundus imaging plays an important role in medical diagnosis. Many algorithms have been proposed. While deep Neural Networks have been attracting enormous attention from computer vision community recent years and several novel works have been done in terms of its application in retinal blood vessel segmentation, most of them are based on supervised learning which requires amount of labeled data, which is both scarce and expensive to obtain. We leverage the power of Deep Convolutional Neural Networks (DCNN) in feature learning, in this work, to achieve this ultimate goal. The highly efficient feature learning of DCNN inspires our novel approach that trains the networks with automatically-generated samples to achieve desirable performance on real-world fundus images. For this, we design a set of rules abstracted from the domain-specific prior knowledge to generate these samples. We argue that, with the high efficiency of DCNN in feature learning, one can achieve this goal by constructing the training dataset with prior knowledge, no manual labeling is needed. This approach allows us to take advantages of supervised learning without labeling. We also build a naive DCNN model to test it. The results on standard benchmarks of fundus imaging show it is competitive to the state-of-the-art methods which implies a potential way to leverage the power of DCNN in feature learning.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 01:04:21 GMT" }, { "version": "v2", "created": "Mon, 1 May 2017 12:13:47 GMT" } ]
2017-05-02T00:00:00
[ [ "Chen", "Yongliang", "" ] ]
TITLE: A Labeling-Free Approach to Supervising Deep Neural Networks for Retinal Blood Vessel Segmentation ABSTRACT: Segmenting blood vessels in fundus imaging plays an important role in medical diagnosis. Many algorithms have been proposed. While deep Neural Networks have been attracting enormous attention from computer vision community recent years and several novel works have been done in terms of its application in retinal blood vessel segmentation, most of them are based on supervised learning which requires amount of labeled data, which is both scarce and expensive to obtain. We leverage the power of Deep Convolutional Neural Networks (DCNN) in feature learning, in this work, to achieve this ultimate goal. The highly efficient feature learning of DCNN inspires our novel approach that trains the networks with automatically-generated samples to achieve desirable performance on real-world fundus images. For this, we design a set of rules abstracted from the domain-specific prior knowledge to generate these samples. We argue that, with the high efficiency of DCNN in feature learning, one can achieve this goal by constructing the training dataset with prior knowledge, no manual labeling is needed. This approach allows us to take advantages of supervised learning without labeling. We also build a naive DCNN model to test it. The results on standard benchmarks of fundus imaging show it is competitive to the state-of-the-art methods which implies a potential way to leverage the power of DCNN in feature learning.
no_new_dataset
0.948298
1705.00108
Matthew Peters
Matthew E. Peters, Waleed Ammar, Chandra Bhagavatula, Russell Power
Semi-supervised sequence tagging with bidirectional language models
To appear in ACL 2017
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Pre-trained word embeddings learned from unlabeled text have become a standard component of neural network architectures for NLP tasks. However, in most cases, the recurrent network that operates on word-level representations to produce context sensitive representations is trained on relatively little labeled data. In this paper, we demonstrate a general semi-supervised approach for adding pre- trained context embeddings from bidirectional language models to NLP systems and apply it to sequence labeling tasks. We evaluate our model on two standard datasets for named entity recognition (NER) and chunking, and in both cases achieve state of the art results, surpassing previous systems that use other forms of transfer or joint learning with additional labeled data and task specific gazetteers.
[ { "version": "v1", "created": "Sat, 29 Apr 2017 01:13:04 GMT" } ]
2017-05-02T00:00:00
[ [ "Peters", "Matthew E.", "" ], [ "Ammar", "Waleed", "" ], [ "Bhagavatula", "Chandra", "" ], [ "Power", "Russell", "" ] ]
TITLE: Semi-supervised sequence tagging with bidirectional language models ABSTRACT: Pre-trained word embeddings learned from unlabeled text have become a standard component of neural network architectures for NLP tasks. However, in most cases, the recurrent network that operates on word-level representations to produce context sensitive representations is trained on relatively little labeled data. In this paper, we demonstrate a general semi-supervised approach for adding pre- trained context embeddings from bidirectional language models to NLP systems and apply it to sequence labeling tasks. We evaluate our model on two standard datasets for named entity recognition (NER) and chunking, and in both cases achieve state of the art results, surpassing previous systems that use other forms of transfer or joint learning with additional labeled data and task specific gazetteers.
no_new_dataset
0.951908
1705.00301
Marei Algarni Mr.
Marei Algarni and Ganesh Sundaramoorthi
SurfCut: Surfaces of Minimal Paths From Topological Structures
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present SurfCut, an algorithm for extracting a smooth, simple surface with an unknown 3D curve boundary from a noisy 3D image and a seed point. Our method is built on the novel observation that certain ridge curves of a function defined on a front propagated using the Fast Marching algorithm lie on the surface. Our method extracts and cuts these ridges to form the surface boundary. Our surface extraction algorithm is built on the novel observation that the surface lies in a valley of the distance from Fast Marching. We show that the resulting surface is a collection of minimal paths. Using the framework of cubical complexes and Morse theory, we design algorithms to extract these critical structures robustly. Experiments on three 3D datasets show the robustness of our method, and that it achieves higher accuracy with lower computational cost than state-of-the-art.
[ { "version": "v1", "created": "Sun, 30 Apr 2017 11:56:51 GMT" } ]
2017-05-02T00:00:00
[ [ "Algarni", "Marei", "" ], [ "Sundaramoorthi", "Ganesh", "" ] ]
TITLE: SurfCut: Surfaces of Minimal Paths From Topological Structures ABSTRACT: We present SurfCut, an algorithm for extracting a smooth, simple surface with an unknown 3D curve boundary from a noisy 3D image and a seed point. Our method is built on the novel observation that certain ridge curves of a function defined on a front propagated using the Fast Marching algorithm lie on the surface. Our method extracts and cuts these ridges to form the surface boundary. Our surface extraction algorithm is built on the novel observation that the surface lies in a valley of the distance from Fast Marching. We show that the resulting surface is a collection of minimal paths. Using the framework of cubical complexes and Morse theory, we design algorithms to extract these critical structures robustly. Experiments on three 3D datasets show the robustness of our method, and that it achieves higher accuracy with lower computational cost than state-of-the-art.
no_new_dataset
0.948394
1705.00346
Andre Luckow
Andre Luckow and Matthew Cook and Nathan Ashcraft and Edwin Weill and Emil Djerekarov and Bennie Vorster
Deep Learning in the Automotive Industry: Applications and Tools
10 pages
null
10.1109/BigData.2016.7841045
null
cs.LG cs.CV cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Deep Learning refers to a set of machine learning techniques that utilize neural networks with many hidden layers for tasks, such as image classification, speech recognition, language understanding. Deep learning has been proven to be very effective in these domains and is pervasively used by many Internet services. In this paper, we describe different automotive uses cases for deep learning in particular in the domain of computer vision. We surveys the current state-of-the-art in libraries, tools and infrastructures (e.\,g.\ GPUs and clouds) for implementing, training and deploying deep neural networks. We particularly focus on convolutional neural networks and computer vision use cases, such as the visual inspection process in manufacturing plants and the analysis of social media data. To train neural networks, curated and labeled datasets are essential. In particular, both the availability and scope of such datasets is typically very limited. A main contribution of this paper is the creation of an automotive dataset, that allows us to learn and automatically recognize different vehicle properties. We describe an end-to-end deep learning application utilizing a mobile app for data collection and process support, and an Amazon-based cloud backend for storage and training. For training we evaluate the use of cloud and on-premises infrastructures (including multiple GPUs) in conjunction with different neural network architectures and frameworks. We assess both the training times as well as the accuracy of the classifier. Finally, we demonstrate the effectiveness of the trained classifier in a real world setting during manufacturing process.
[ { "version": "v1", "created": "Sun, 30 Apr 2017 17:17:44 GMT" } ]
2017-05-02T00:00:00
[ [ "Luckow", "Andre", "" ], [ "Cook", "Matthew", "" ], [ "Ashcraft", "Nathan", "" ], [ "Weill", "Edwin", "" ], [ "Djerekarov", "Emil", "" ], [ "Vorster", "Bennie", "" ] ]
TITLE: Deep Learning in the Automotive Industry: Applications and Tools ABSTRACT: Deep Learning refers to a set of machine learning techniques that utilize neural networks with many hidden layers for tasks, such as image classification, speech recognition, language understanding. Deep learning has been proven to be very effective in these domains and is pervasively used by many Internet services. In this paper, we describe different automotive uses cases for deep learning in particular in the domain of computer vision. We surveys the current state-of-the-art in libraries, tools and infrastructures (e.\,g.\ GPUs and clouds) for implementing, training and deploying deep neural networks. We particularly focus on convolutional neural networks and computer vision use cases, such as the visual inspection process in manufacturing plants and the analysis of social media data. To train neural networks, curated and labeled datasets are essential. In particular, both the availability and scope of such datasets is typically very limited. A main contribution of this paper is the creation of an automotive dataset, that allows us to learn and automatically recognize different vehicle properties. We describe an end-to-end deep learning application utilizing a mobile app for data collection and process support, and an Amazon-based cloud backend for storage and training. For training we evaluate the use of cloud and on-premises infrastructures (including multiple GPUs) in conjunction with different neural network architectures and frameworks. We assess both the training times as well as the accuracy of the classifier. Finally, we demonstrate the effectiveness of the trained classifier in a real world setting during manufacturing process.
new_dataset
0.964456
1705.00366
Danna Gurari
Danna Gurari and Kun He and Bo Xiong and Jianming Zhang and Mehrnoosh Sameki and Suyog Dutt Jain and Stan Sclaroff and Margrit Betke and Kristen Grauman
Predicting Foreground Object Ambiguity and Efficiently Crowdsourcing the Segmentation(s)
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose the ambiguity problem for the foreground object segmentation task and motivate the importance of estimating and accounting for this ambiguity when designing vision systems. Specifically, we distinguish between images which lead multiple annotators to segment different foreground objects (ambiguous) versus minor inter-annotator differences of the same object. Taking images from eight widely used datasets, we crowdsource labeling the images as "ambiguous" or "not ambiguous" to segment in order to construct a new dataset we call STATIC. Using STATIC, we develop a system that automatically predicts which images are ambiguous. Experiments demonstrate the advantage of our prediction system over existing saliency-based methods on images from vision benchmarks and images taken by blind people who are trying to recognize objects in their environment. Finally, we introduce a crowdsourcing system to achieve cost savings for collecting the diversity of all valid "ground truth" foreground object segmentations by collecting extra segmentations only when ambiguity is expected. Experiments show our system eliminates up to 47% of human effort compared to existing crowdsourcing methods with no loss in capturing the diversity of ground truths.
[ { "version": "v1", "created": "Sun, 30 Apr 2017 19:27:30 GMT" } ]
2017-05-02T00:00:00
[ [ "Gurari", "Danna", "" ], [ "He", "Kun", "" ], [ "Xiong", "Bo", "" ], [ "Zhang", "Jianming", "" ], [ "Sameki", "Mehrnoosh", "" ], [ "Jain", "Suyog Dutt", "" ], [ "Sclaroff", "Stan", "" ], [ "Betke", "Margrit", "" ], [ "Grauman", "Kristen", "" ] ]
TITLE: Predicting Foreground Object Ambiguity and Efficiently Crowdsourcing the Segmentation(s) ABSTRACT: We propose the ambiguity problem for the foreground object segmentation task and motivate the importance of estimating and accounting for this ambiguity when designing vision systems. Specifically, we distinguish between images which lead multiple annotators to segment different foreground objects (ambiguous) versus minor inter-annotator differences of the same object. Taking images from eight widely used datasets, we crowdsource labeling the images as "ambiguous" or "not ambiguous" to segment in order to construct a new dataset we call STATIC. Using STATIC, we develop a system that automatically predicts which images are ambiguous. Experiments demonstrate the advantage of our prediction system over existing saliency-based methods on images from vision benchmarks and images taken by blind people who are trying to recognize objects in their environment. Finally, we introduce a crowdsourcing system to achieve cost savings for collecting the diversity of all valid "ground truth" foreground object segmentations by collecting extra segmentations only when ambiguity is expected. Experiments show our system eliminates up to 47% of human effort compared to existing crowdsourcing methods with no loss in capturing the diversity of ground truths.
new_dataset
0.954647
1705.00399
Natali Ruchansky
Natali Ruchansky and Mark Crovella and Evimaria Terzi
Matrix completion with queries
Proceedings of the 21th ACM SIGKDD International Conference on Knowledge Discovery and Data Mining
null
10.1145/2783258.2783259
null
cs.LG cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In many applications, e.g., recommender systems and traffic monitoring, the data comes in the form of a matrix that is only partially observed and low rank. A fundamental data-analysis task for these datasets is matrix completion, where the goal is to accurately infer the entries missing from the matrix. Even when the data satisfies the low-rank assumption, classical matrix-completion methods may output completions with significant error -- in that the reconstructed matrix differs significantly from the true underlying matrix. Often, this is due to the fact that the information contained in the observed entries is insufficient. In this work, we address this problem by proposing an active version of matrix completion, where queries can be made to the true underlying matrix. Subsequently, we design Order&Extend, which is the first algorithm to unify a matrix-completion approach and a querying strategy into a single algorithm. Order&Extend is able identify and alleviate insufficient information by judiciously querying a small number of additional entries. In an extensive experimental evaluation on real-world datasets, we demonstrate that our algorithm is efficient and is able to accurately reconstruct the true matrix while asking only a small number of queries.
[ { "version": "v1", "created": "Mon, 1 May 2017 01:58:45 GMT" } ]
2017-05-02T00:00:00
[ [ "Ruchansky", "Natali", "" ], [ "Crovella", "Mark", "" ], [ "Terzi", "Evimaria", "" ] ]
TITLE: Matrix completion with queries ABSTRACT: In many applications, e.g., recommender systems and traffic monitoring, the data comes in the form of a matrix that is only partially observed and low rank. A fundamental data-analysis task for these datasets is matrix completion, where the goal is to accurately infer the entries missing from the matrix. Even when the data satisfies the low-rank assumption, classical matrix-completion methods may output completions with significant error -- in that the reconstructed matrix differs significantly from the true underlying matrix. Often, this is due to the fact that the information contained in the observed entries is insufficient. In this work, we address this problem by proposing an active version of matrix completion, where queries can be made to the true underlying matrix. Subsequently, we design Order&Extend, which is the first algorithm to unify a matrix-completion approach and a querying strategy into a single algorithm. Order&Extend is able identify and alleviate insufficient information by judiciously querying a small number of additional entries. In an extensive experimental evaluation on real-world datasets, we demonstrate that our algorithm is efficient and is able to accurately reconstruct the true matrix while asking only a small number of queries.
no_new_dataset
0.940298
1705.00415
Travis Gagie
Leo Ferres, Jos\'e Fuentes-Sep\'ulveda, Travis Gagie, Meng He and Gonzalo Navarro
Parallel Construction of Compact Planar Embeddings
null
null
null
null
cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The sheer sizes of modern datasets are forcing data-structure designers to consider seriously both parallel construction and compactness. To achieve those goals we need to design a parallel algorithm with good scalability and with low memory consumption. An algorithm with good scalability improves its performance when the number of available cores increases, and an algorithm with low memory consumption uses memory proportional to the space used by the dataset in uncompact form. In this work, we discuss the engineering of a parallel algorithm with linear work and logarithmic span for the construction of the compact representation of planar embeddings. We also provide an experimental study of our implementation and prove experimentally that it has good scalability and low memory consumption. Additionally, we describe and test experimentally queries supported by the compact representation.
[ { "version": "v1", "created": "Mon, 1 May 2017 03:50:09 GMT" } ]
2017-05-02T00:00:00
[ [ "Ferres", "Leo", "" ], [ "Fuentes-Sepúlveda", "José", "" ], [ "Gagie", "Travis", "" ], [ "He", "Meng", "" ], [ "Navarro", "Gonzalo", "" ] ]
TITLE: Parallel Construction of Compact Planar Embeddings ABSTRACT: The sheer sizes of modern datasets are forcing data-structure designers to consider seriously both parallel construction and compactness. To achieve those goals we need to design a parallel algorithm with good scalability and with low memory consumption. An algorithm with good scalability improves its performance when the number of available cores increases, and an algorithm with low memory consumption uses memory proportional to the space used by the dataset in uncompact form. In this work, we discuss the engineering of a parallel algorithm with linear work and logarithmic span for the construction of the compact representation of planar embeddings. We also provide an experimental study of our implementation and prove experimentally that it has good scalability and low memory consumption. Additionally, we describe and test experimentally queries supported by the compact representation.
no_new_dataset
0.947186
1705.00462
Francisco Paisana Francisco Paisana
Ahmed Selim, Francisco Paisana, Jerome A. Arokkiam, Yi Zhang, Linda Doyle, Luiz A. DaSilva
Spectrum Monitoring for Radar Bands using Deep Convolutional Neural Networks
7 pages, 10 figures, conference
null
null
null
cs.NI cs.IT cs.LG math.IT
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we present a spectrum monitoring framework for the detection of radar signals in spectrum sharing scenarios. The core of our framework is a deep convolutional neural network (CNN) model that enables Measurement Capable Devices to identify the presence of radar signals in the radio spectrum, even when these signals are overlapped with other sources of interference, such as commercial LTE and WLAN. We collected a large dataset of RF measurements, which include the transmissions of multiple radar pulse waveforms, downlink LTE, WLAN, and thermal noise. We propose a pre-processing data representation that leverages the amplitude and phase shifts of the collected samples. This representation allows our CNN model to achieve a classification accuracy of 99.6% on our testing dataset. The trained CNN model is then tested under various SNR values, outperforming other models, such as spectrogram-based CNN models.
[ { "version": "v1", "created": "Mon, 1 May 2017 10:37:43 GMT" } ]
2017-05-02T00:00:00
[ [ "Selim", "Ahmed", "" ], [ "Paisana", "Francisco", "" ], [ "Arokkiam", "Jerome A.", "" ], [ "Zhang", "Yi", "" ], [ "Doyle", "Linda", "" ], [ "DaSilva", "Luiz A.", "" ] ]
TITLE: Spectrum Monitoring for Radar Bands using Deep Convolutional Neural Networks ABSTRACT: In this paper, we present a spectrum monitoring framework for the detection of radar signals in spectrum sharing scenarios. The core of our framework is a deep convolutional neural network (CNN) model that enables Measurement Capable Devices to identify the presence of radar signals in the radio spectrum, even when these signals are overlapped with other sources of interference, such as commercial LTE and WLAN. We collected a large dataset of RF measurements, which include the transmissions of multiple radar pulse waveforms, downlink LTE, WLAN, and thermal noise. We propose a pre-processing data representation that leverages the amplitude and phase shifts of the collected samples. This representation allows our CNN model to achieve a classification accuracy of 99.6% on our testing dataset. The trained CNN model is then tested under various SNR values, outperforming other models, such as spectrogram-based CNN models.
new_dataset
0.962988
1705.00534
Bo Li
Bo Li, Yuchao Dai, Huahui Chen, Mingyi He
Single image depth estimation by dilated deep residual convolutional neural network and soft-weight-sum inference
null
null
null
null
cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper proposes a new residual convolutional neural network (CNN) architecture for single image depth estimation. Compared with existing deep CNN based methods, our method achieves much better results with fewer training examples and model parameters. The advantages of our method come from the usage of dilated convolution, skip connection architecture and soft-weight-sum inference. Experimental evaluation on the NYU Depth V2 dataset shows that our method outperforms other state-of-the-art methods by a margin.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 06:07:05 GMT" } ]
2017-05-02T00:00:00
[ [ "Li", "Bo", "" ], [ "Dai", "Yuchao", "" ], [ "Chen", "Huahui", "" ], [ "He", "Mingyi", "" ] ]
TITLE: Single image depth estimation by dilated deep residual convolutional neural network and soft-weight-sum inference ABSTRACT: This paper proposes a new residual convolutional neural network (CNN) architecture for single image depth estimation. Compared with existing deep CNN based methods, our method achieves much better results with fewer training examples and model parameters. The advantages of our method come from the usage of dilated convolution, skip connection architecture and soft-weight-sum inference. Experimental evaluation on the NYU Depth V2 dataset shows that our method outperforms other state-of-the-art methods by a margin.
no_new_dataset
0.952264
1705.00548
Reza Farahbakhsh
Reza Farahbakhsh, Angel Cuevas, Ruben Cuevas, Roberto Gonzalez, Noel Crespi
Understanding the evolution of multimedia content in the Internet through BitTorrent glasses
Farahbakhsh, Reza, et al. "Understanding the evolution of multimedia content in the internet through bittorrent glasses." IEEE Network 27.6 (2013): 80-88
IEEE Network 27.6 (2013): 80-88
null
null
cs.NI cs.MM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Today's Internet traffic is mostly dominated by multimedia content and the prediction is that this trend will intensify in the future. Therefore, main Internet players, such as ISPs, content delivery platforms (e.g. Youtube, Bitorrent, Netflix, etc) or CDN operators, need to understand the evolution of multimedia content availability and popularity in order to adapt their infrastructures and resources to satisfy clients requirements while they minimize their costs. This paper presents a thorough analysis on the evolution of multimedia content available in BitTorrent. Specifically, we analyze the evolution of four relevant metrics across different content categories: content availability, content popularity, content size and user's feedback. To this end we leverage a large-scale dataset formed by 4 snapshots collected from the most popular BitTorrent portal, namely The Pirate Bay, between Nov. 2009 and Feb. 2012. Overall our dataset is formed by more than 160k content that attracted more than 185M of download sessions.
[ { "version": "v1", "created": "Mon, 1 May 2017 14:45:00 GMT" } ]
2017-05-02T00:00:00
[ [ "Farahbakhsh", "Reza", "" ], [ "Cuevas", "Angel", "" ], [ "Cuevas", "Ruben", "" ], [ "Gonzalez", "Roberto", "" ], [ "Crespi", "Noel", "" ] ]
TITLE: Understanding the evolution of multimedia content in the Internet through BitTorrent glasses ABSTRACT: Today's Internet traffic is mostly dominated by multimedia content and the prediction is that this trend will intensify in the future. Therefore, main Internet players, such as ISPs, content delivery platforms (e.g. Youtube, Bitorrent, Netflix, etc) or CDN operators, need to understand the evolution of multimedia content availability and popularity in order to adapt their infrastructures and resources to satisfy clients requirements while they minimize their costs. This paper presents a thorough analysis on the evolution of multimedia content available in BitTorrent. Specifically, we analyze the evolution of four relevant metrics across different content categories: content availability, content popularity, content size and user's feedback. To this end we leverage a large-scale dataset formed by 4 snapshots collected from the most popular BitTorrent portal, namely The Pirate Bay, between Nov. 2009 and Feb. 2012. Overall our dataset is formed by more than 160k content that attracted more than 185M of download sessions.
new_dataset
0.962497
1601.05613
Boyue Wang
Boyue Wang and Yongli Hu and Junbin Gao and Yanfeng Sun and Baocai Yin
Partial Sum Minimization of Singular Values Representation on Grassmann Manifolds
Submitting to ACM Transactions on Knowledge Discovery from Data with minor revision
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
As a significant subspace clustering method, low rank representation (LRR) has attracted great attention in recent years. To further improve the performance of LRR and extend its applications, there are several issues to be resolved. The nuclear norm in LRR does not sufficiently use the prior knowledge of the rank which is known in many practical problems. The LRR is designed for vectorial data from linear spaces, thus not suitable for high dimensional data with intrinsic non-linear manifold structure. This paper proposes an extended LRR model for manifold-valued Grassmann data which incorporates prior knowledge by minimizing partial sum of singular values instead of the nuclear norm, namely Partial Sum minimization of Singular Values Representation (GPSSVR). The new model not only enforces the global structure of data in low rank, but also retains important information by minimizing only smaller singular values. To further maintain the local structures among Grassmann points, we also integrate the Laplacian penalty with GPSSVR. An effective algorithm is proposed to solve the optimization problem based on the GPSSVR model. The proposed model and algorithms are assessed on some widely used human action video datasets and a real scenery dataset. The experimental results show that the proposed methods obviously outperform other state-of-the-art methods.
[ { "version": "v1", "created": "Thu, 21 Jan 2016 12:47:17 GMT" }, { "version": "v2", "created": "Sun, 31 Jan 2016 01:57:28 GMT" }, { "version": "v3", "created": "Fri, 28 Apr 2017 03:19:27 GMT" } ]
2017-05-01T00:00:00
[ [ "Wang", "Boyue", "" ], [ "Hu", "Yongli", "" ], [ "Gao", "Junbin", "" ], [ "Sun", "Yanfeng", "" ], [ "Yin", "Baocai", "" ] ]
TITLE: Partial Sum Minimization of Singular Values Representation on Grassmann Manifolds ABSTRACT: As a significant subspace clustering method, low rank representation (LRR) has attracted great attention in recent years. To further improve the performance of LRR and extend its applications, there are several issues to be resolved. The nuclear norm in LRR does not sufficiently use the prior knowledge of the rank which is known in many practical problems. The LRR is designed for vectorial data from linear spaces, thus not suitable for high dimensional data with intrinsic non-linear manifold structure. This paper proposes an extended LRR model for manifold-valued Grassmann data which incorporates prior knowledge by minimizing partial sum of singular values instead of the nuclear norm, namely Partial Sum minimization of Singular Values Representation (GPSSVR). The new model not only enforces the global structure of data in low rank, but also retains important information by minimizing only smaller singular values. To further maintain the local structures among Grassmann points, we also integrate the Laplacian penalty with GPSSVR. An effective algorithm is proposed to solve the optimization problem based on the GPSSVR model. The proposed model and algorithms are assessed on some widely used human action video datasets and a real scenery dataset. The experimental results show that the proposed methods obviously outperform other state-of-the-art methods.
no_new_dataset
0.946101
1611.02049
Michal Nowicki
Micha{\l} Nowicki and Jan Wietrzykowski
Low-effort place recognition with WiFi fingerprints using deep learning
null
null
10.1007/978-3-319-54042-9_57
null
cs.RO cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Using WiFi signals for indoor localization is the main localization modality of the existing personal indoor localization systems operating on mobile devices. WiFi fingerprinting is also used for mobile robots, as WiFi signals are usually available indoors and can provide rough initial position estimate or can be used together with other positioning systems. Currently, the best solutions rely on filtering, manual data analysis, and time-consuming parameter tuning to achieve reliable and accurate localization. In this work, we propose to use deep neural networks to significantly lower the work-force burden of the localization system design, while still achieving satisfactory results. Assuming the state-of-the-art hierarchical approach, we employ the DNN system for building/floor classification. We show that stacked autoencoders allow to efficiently reduce the feature space in order to achieve robust and precise classification. The proposed architecture is verified on the publicly available UJIIndoorLoc dataset and the results are compared with other solutions.
[ { "version": "v1", "created": "Mon, 7 Nov 2016 13:47:25 GMT" }, { "version": "v2", "created": "Fri, 28 Apr 2017 06:32:25 GMT" } ]
2017-05-01T00:00:00
[ [ "Nowicki", "Michał", "" ], [ "Wietrzykowski", "Jan", "" ] ]
TITLE: Low-effort place recognition with WiFi fingerprints using deep learning ABSTRACT: Using WiFi signals for indoor localization is the main localization modality of the existing personal indoor localization systems operating on mobile devices. WiFi fingerprinting is also used for mobile robots, as WiFi signals are usually available indoors and can provide rough initial position estimate or can be used together with other positioning systems. Currently, the best solutions rely on filtering, manual data analysis, and time-consuming parameter tuning to achieve reliable and accurate localization. In this work, we propose to use deep neural networks to significantly lower the work-force burden of the localization system design, while still achieving satisfactory results. Assuming the state-of-the-art hierarchical approach, we employ the DNN system for building/floor classification. We show that stacked autoencoders allow to efficiently reduce the feature space in order to achieve robust and precise classification. The proposed architecture is verified on the publicly available UJIIndoorLoc dataset and the results are compared with other solutions.
no_new_dataset
0.953057
1611.02054
Michal Nowicki
Jan Wietrzykowski and Micha{\l} Nowicki and Piotr Skrzypczy\'nski
Adopting the FAB-MAP algorithm for indoor localization with WiFi fingerprints
null
null
10.1007/978-3-319-54042-9_58
null
cs.RO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Personal indoor localization is usually accomplished by fusing information from various sensors. A common choice is to use the WiFi adapter that provides information about Access Points that can be found in the vicinity. Unfortunately, state-of-the-art approaches to WiFi-based localization often employ very dense maps of the WiFi signal distribution, and require a time-consuming process of parameter selection. On the other hand, camera images are commonly used for visual place recognition, detecting whenever the user observes a scene similar to the one already recorded in a database. Visual place recognition algorithms can work with sparse databases of recorded scenes and are in general simple to parametrize. Therefore, we propose a WiFi-based global localization method employing the structure of the well-known FAB-MAP visual place recognition algorithm. Similarly to FAB-MAP our method uses Chow-Liu trees to estimate a joint probability distribution of re-observation of a place given a set of features extracted at places visited so far. However, we are the first who apply this idea to recorded WiFi scans instead of visual words. The new method is evaluated on the UJIIndoorLoc dataset used in the EvAAL competition, allowing fair comparison with other solutions.
[ { "version": "v1", "created": "Mon, 7 Nov 2016 13:55:35 GMT" }, { "version": "v2", "created": "Fri, 28 Apr 2017 06:29:48 GMT" } ]
2017-05-01T00:00:00
[ [ "Wietrzykowski", "Jan", "" ], [ "Nowicki", "Michał", "" ], [ "Skrzypczyński", "Piotr", "" ] ]
TITLE: Adopting the FAB-MAP algorithm for indoor localization with WiFi fingerprints ABSTRACT: Personal indoor localization is usually accomplished by fusing information from various sensors. A common choice is to use the WiFi adapter that provides information about Access Points that can be found in the vicinity. Unfortunately, state-of-the-art approaches to WiFi-based localization often employ very dense maps of the WiFi signal distribution, and require a time-consuming process of parameter selection. On the other hand, camera images are commonly used for visual place recognition, detecting whenever the user observes a scene similar to the one already recorded in a database. Visual place recognition algorithms can work with sparse databases of recorded scenes and are in general simple to parametrize. Therefore, we propose a WiFi-based global localization method employing the structure of the well-known FAB-MAP visual place recognition algorithm. Similarly to FAB-MAP our method uses Chow-Liu trees to estimate a joint probability distribution of re-observation of a place given a set of features extracted at places visited so far. However, we are the first who apply this idea to recorded WiFi scans instead of visual words. The new method is evaluated on the UJIIndoorLoc dataset used in the EvAAL competition, allowing fair comparison with other solutions.
no_new_dataset
0.949153
1701.04658
Kevis-Kokitsi Maninis
Kevis-Kokitsi Maninis and Jordi Pont-Tuset and Pablo Arbel\'aez and Luc Van Gool
Convolutional Oriented Boundaries: From Image Segmentation to High-Level Tasks
Accepted by T-PAMI. Extended version of "Convolutional Oriented Boundaries", ECCV 2016 (arXiv:1608.02755). Project page: http://www.vision.ee.ethz.ch/~cvlsegmentation/cob/
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present Convolutional Oriented Boundaries (COB), which produces multiscale oriented contours and region hierarchies starting from generic image classification Convolutional Neural Networks (CNNs). COB is computationally efficient, because it requires a single CNN forward pass for multi-scale contour detection and it uses a novel sparse boundary representation for hierarchical segmentation; it gives a significant leap in performance over the state-of-the-art, and it generalizes very well to unseen categories and datasets. Particularly, we show that learning to estimate not only contour strength but also orientation provides more accurate results. We perform extensive experiments for low-level applications on BSDS, PASCAL Context, PASCAL Segmentation, and NYUD to evaluate boundary detection performance, showing that COB provides state-of-the-art contours and region hierarchies in all datasets. We also evaluate COB on high-level tasks when coupled with multiple pipelines for object proposals, semantic contours, semantic segmentation, and object detection on MS-COCO, SBD, and PASCAL; showing that COB also improves the results for all tasks.
[ { "version": "v1", "created": "Tue, 17 Jan 2017 13:04:33 GMT" }, { "version": "v2", "created": "Fri, 28 Apr 2017 17:08:42 GMT" } ]
2017-05-01T00:00:00
[ [ "Maninis", "Kevis-Kokitsi", "" ], [ "Pont-Tuset", "Jordi", "" ], [ "Arbeláez", "Pablo", "" ], [ "Van Gool", "Luc", "" ] ]
TITLE: Convolutional Oriented Boundaries: From Image Segmentation to High-Level Tasks ABSTRACT: We present Convolutional Oriented Boundaries (COB), which produces multiscale oriented contours and region hierarchies starting from generic image classification Convolutional Neural Networks (CNNs). COB is computationally efficient, because it requires a single CNN forward pass for multi-scale contour detection and it uses a novel sparse boundary representation for hierarchical segmentation; it gives a significant leap in performance over the state-of-the-art, and it generalizes very well to unseen categories and datasets. Particularly, we show that learning to estimate not only contour strength but also orientation provides more accurate results. We perform extensive experiments for low-level applications on BSDS, PASCAL Context, PASCAL Segmentation, and NYUD to evaluate boundary detection performance, showing that COB provides state-of-the-art contours and region hierarchies in all datasets. We also evaluate COB on high-level tasks when coupled with multiple pipelines for object proposals, semantic contours, semantic segmentation, and object detection on MS-COCO, SBD, and PASCAL; showing that COB also improves the results for all tasks.
no_new_dataset
0.950732
1703.01333
Steve Jan
Steve T.K. Jan and Chun Wang and Qing Zhang and Gang Wang
Towards Monetary Incentives in Social Q&A Services
null
null
null
null
cs.AI cs.HC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Community-based question answering (CQA) services are facing key challenges to motivate domain experts to provide timely answers. Recently, CQA services are exploring new incentive models to engage experts and celebrities by allowing them to set a price on their answers. In this paper, we perform a data-driven analysis on two emerging payment-based CQA systems: Fenda (China) and Whale (US). By analyzing a large dataset of 220K questions (worth 1 million USD collectively), we examine how monetary incentives affect different players in the system. We find that, while monetary incentive enables quick answers from experts, it also drives certain users to aggressively game the system for profits. In addition, in this supplier-driven marketplace, users need to proactively adjust their price to make profits. Famous people are unwilling to lower their price, which in turn hurts their income and engagement over time. Finally, we discuss the key implications to future CQA design.
[ { "version": "v1", "created": "Fri, 3 Mar 2017 20:36:38 GMT" }, { "version": "v2", "created": "Fri, 28 Apr 2017 01:48:18 GMT" } ]
2017-05-01T00:00:00
[ [ "Jan", "Steve T. K.", "" ], [ "Wang", "Chun", "" ], [ "Zhang", "Qing", "" ], [ "Wang", "Gang", "" ] ]
TITLE: Towards Monetary Incentives in Social Q&A Services ABSTRACT: Community-based question answering (CQA) services are facing key challenges to motivate domain experts to provide timely answers. Recently, CQA services are exploring new incentive models to engage experts and celebrities by allowing them to set a price on their answers. In this paper, we perform a data-driven analysis on two emerging payment-based CQA systems: Fenda (China) and Whale (US). By analyzing a large dataset of 220K questions (worth 1 million USD collectively), we examine how monetary incentives affect different players in the system. We find that, while monetary incentive enables quick answers from experts, it also drives certain users to aggressively game the system for profits. In addition, in this supplier-driven marketplace, users need to proactively adjust their price to make profits. Famous people are unwilling to lower their price, which in turn hurts their income and engagement over time. Finally, we discuss the key implications to future CQA design.
no_new_dataset
0.946498
1704.00051
Danqi Chen
Danqi Chen, Adam Fisch, Jason Weston and Antoine Bordes
Reading Wikipedia to Answer Open-Domain Questions
ACL2017, 10 pages
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper proposes to tackle open- domain question answering using Wikipedia as the unique knowledge source: the answer to any factoid question is a text span in a Wikipedia article. This task of machine reading at scale combines the challenges of document retrieval (finding the relevant articles) with that of machine comprehension of text (identifying the answer spans from those articles). Our approach combines a search component based on bigram hashing and TF-IDF matching with a multi-layer recurrent neural network model trained to detect answers in Wikipedia paragraphs. Our experiments on multiple existing QA datasets indicate that (1) both modules are highly competitive with respect to existing counterparts and (2) multitask learning using distant supervision on their combination is an effective complete system on this challenging task.
[ { "version": "v1", "created": "Fri, 31 Mar 2017 20:39:10 GMT" }, { "version": "v2", "created": "Fri, 28 Apr 2017 03:53:14 GMT" } ]
2017-05-01T00:00:00
[ [ "Chen", "Danqi", "" ], [ "Fisch", "Adam", "" ], [ "Weston", "Jason", "" ], [ "Bordes", "Antoine", "" ] ]
TITLE: Reading Wikipedia to Answer Open-Domain Questions ABSTRACT: This paper proposes to tackle open- domain question answering using Wikipedia as the unique knowledge source: the answer to any factoid question is a text span in a Wikipedia article. This task of machine reading at scale combines the challenges of document retrieval (finding the relevant articles) with that of machine comprehension of text (identifying the answer spans from those articles). Our approach combines a search component based on bigram hashing and TF-IDF matching with a multi-layer recurrent neural network model trained to detect answers in Wikipedia paragraphs. Our experiments on multiple existing QA datasets indicate that (1) both modules are highly competitive with respect to existing counterparts and (2) multitask learning using distant supervision on their combination is an effective complete system on this challenging task.
no_new_dataset
0.952131
1704.08723
Chenliang Xu
Chenliang Xu, Caiming Xiong and Jason J. Corso
Action Understanding with Multiple Classes of Actors
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Despite the rapid progress, existing works on action understanding focus strictly on one type of action agent, which we call actor---a human adult, ignoring the diversity of actions performed by other actors. To overcome this narrow viewpoint, our paper marks the first effort in the computer vision community to jointly consider algorithmic understanding of various types of actors undergoing various actions. To begin with, we collect a large annotated Actor-Action Dataset (A2D) that consists of 3782 short videos and 31 temporally untrimmed long videos. We formulate the general actor-action understanding problem and instantiate it at various granularities: video-level single- and multiple-label actor-action recognition, and pixel-level actor-action segmentation. We propose and examine a comprehensive set of graphical models that consider the various types of interplay among actors and actions. Our findings have led us to conclusive evidence that the joint modeling of actor and action improves performance over modeling each of them independently, and further improvement can be obtained by considering the multi-scale natural in video understanding. Hence, our paper concludes the argument of the value of explicit consideration of various actors in comprehensive action understanding and provides a dataset and a benchmark for later works exploring this new problem.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 19:20:50 GMT" } ]
2017-05-01T00:00:00
[ [ "Xu", "Chenliang", "" ], [ "Xiong", "Caiming", "" ], [ "Corso", "Jason J.", "" ] ]
TITLE: Action Understanding with Multiple Classes of Actors ABSTRACT: Despite the rapid progress, existing works on action understanding focus strictly on one type of action agent, which we call actor---a human adult, ignoring the diversity of actions performed by other actors. To overcome this narrow viewpoint, our paper marks the first effort in the computer vision community to jointly consider algorithmic understanding of various types of actors undergoing various actions. To begin with, we collect a large annotated Actor-Action Dataset (A2D) that consists of 3782 short videos and 31 temporally untrimmed long videos. We formulate the general actor-action understanding problem and instantiate it at various granularities: video-level single- and multiple-label actor-action recognition, and pixel-level actor-action segmentation. We propose and examine a comprehensive set of graphical models that consider the various types of interplay among actors and actions. Our findings have led us to conclusive evidence that the joint modeling of actor and action improves performance over modeling each of them independently, and further improvement can be obtained by considering the multi-scale natural in video understanding. Hence, our paper concludes the argument of the value of explicit consideration of various actors in comprehensive action understanding and provides a dataset and a benchmark for later works exploring this new problem.
new_dataset
0.954265
1704.08729
Dorian Cazau
Dorian Cazau and Yuancheng Wang and Olivier Adam and Qiao Wang and Gr\'egory Nuel
Calibration of a two-state pitch-wise HMM method for note segmentation in Automatic Music Transcription systems
null
null
null
null
stat.ME cs.SD
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many methods for automatic music transcription involves a multi-pitch estimation method that estimates an activity score for each pitch. A second processing step, called note segmentation, has to be performed for each pitch in order to identify the time intervals when the notes are played. In this study, a pitch-wise two-state on/off firstorder Hidden Markov Model (HMM) is developed for note segmentation. A complete parametrization of the HMM sigmoid function is proposed, based on its original regression formulation, including a parameter alpha of slope smoothing and beta? of thresholding contrast. A comparative evaluation of different note segmentation strategies was performed, differentiated according to whether they use a fixed threshold, called "Hard Thresholding" (HT), or a HMM-based thresholding method, called "Soft Thresholding" (ST). This evaluation was done following MIREX standards and using the MAPS dataset. Also, different transcription scenarios and recording natures were tested using three units of the Degradation toolbox. Results show that note segmentation through a HMM soft thresholding with a data-based optimization of the {alpha,beta} parameter couple significantly enhances transcription performance.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 19:48:09 GMT" } ]
2017-05-01T00:00:00
[ [ "Cazau", "Dorian", "" ], [ "Wang", "Yuancheng", "" ], [ "Adam", "Olivier", "" ], [ "Wang", "Qiao", "" ], [ "Nuel", "Grégory", "" ] ]
TITLE: Calibration of a two-state pitch-wise HMM method for note segmentation in Automatic Music Transcription systems ABSTRACT: Many methods for automatic music transcription involves a multi-pitch estimation method that estimates an activity score for each pitch. A second processing step, called note segmentation, has to be performed for each pitch in order to identify the time intervals when the notes are played. In this study, a pitch-wise two-state on/off firstorder Hidden Markov Model (HMM) is developed for note segmentation. A complete parametrization of the HMM sigmoid function is proposed, based on its original regression formulation, including a parameter alpha of slope smoothing and beta? of thresholding contrast. A comparative evaluation of different note segmentation strategies was performed, differentiated according to whether they use a fixed threshold, called "Hard Thresholding" (HT), or a HMM-based thresholding method, called "Soft Thresholding" (ST). This evaluation was done following MIREX standards and using the MAPS dataset. Also, different transcription scenarios and recording natures were tested using three units of the Degradation toolbox. Results show that note segmentation through a HMM soft thresholding with a data-based optimization of the {alpha,beta} parameter couple significantly enhances transcription performance.
no_new_dataset
0.950088
1704.08740
Mahdi Kalayeh
Mahdi M. Kalayeh, Boqing Gong, Mubarak Shah
Improving Facial Attribute Prediction using Semantic Segmentation
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Attributes are semantically meaningful characteristics whose applicability widely crosses category boundaries. They are particularly important in describing and recognizing concepts where no explicit training example is given, \textit{e.g., zero-shot learning}. Additionally, since attributes are human describable, they can be used for efficient human-computer interaction. In this paper, we propose to employ semantic segmentation to improve facial attribute prediction. The core idea lies in the fact that many facial attributes describe local properties. In other words, the probability of an attribute to appear in a face image is far from being uniform in the spatial domain. We build our facial attribute prediction model jointly with a deep semantic segmentation network. This harnesses the localization cues learned by the semantic segmentation to guide the attention of the attribute prediction to the regions where different attributes naturally show up. As a result of this approach, in addition to recognition, we are able to localize the attributes, despite merely having access to image level labels (weak supervision) during training. We evaluate our proposed method on CelebA and LFWA datasets and achieve superior results to the prior arts. Furthermore, we show that in the reverse problem, semantic face parsing improves when facial attributes are available. That reaffirms the need to jointly model these two interconnected tasks.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 20:41:50 GMT" } ]
2017-05-01T00:00:00
[ [ "Kalayeh", "Mahdi M.", "" ], [ "Gong", "Boqing", "" ], [ "Shah", "Mubarak", "" ] ]
TITLE: Improving Facial Attribute Prediction using Semantic Segmentation ABSTRACT: Attributes are semantically meaningful characteristics whose applicability widely crosses category boundaries. They are particularly important in describing and recognizing concepts where no explicit training example is given, \textit{e.g., zero-shot learning}. Additionally, since attributes are human describable, they can be used for efficient human-computer interaction. In this paper, we propose to employ semantic segmentation to improve facial attribute prediction. The core idea lies in the fact that many facial attributes describe local properties. In other words, the probability of an attribute to appear in a face image is far from being uniform in the spatial domain. We build our facial attribute prediction model jointly with a deep semantic segmentation network. This harnesses the localization cues learned by the semantic segmentation to guide the attention of the attribute prediction to the regions where different attributes naturally show up. As a result of this approach, in addition to recognition, we are able to localize the attributes, despite merely having access to image level labels (weak supervision) during training. We evaluate our proposed method on CelebA and LFWA datasets and achieve superior results to the prior arts. Furthermore, we show that in the reverse problem, semantic face parsing improves when facial attributes are available. That reaffirms the need to jointly model these two interconnected tasks.
no_new_dataset
0.947962
1704.08759
Shichao Yang
Shichao Yang, Sandeep Konam, Chen Ma, Stephanie Rosenthal, Manuela Veloso, Sebastian Scherer
Obstacle Avoidance through Deep Networks based Intermediate Perception
null
null
null
null
cs.RO cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Obstacle avoidance from monocular images is a challenging problem for robots. Though multi-view structure-from-motion could build 3D maps, it is not robust in textureless environments. Some learning based methods exploit human demonstration to predict a steering command directly from a single image. However, this method is usually biased towards certain tasks or demonstration scenarios and also biased by human understanding. In this paper, we propose a new method to predict a trajectory from images. We train our system on more diverse NYUv2 dataset. The ground truth trajectory is computed from the designed cost functions automatically. The Convolutional Neural Network perception is divided into two stages: first, predict depth map and surface normal from RGB images, which are two important geometric properties related to 3D obstacle representation. Second, predict the trajectory from the depth and normal. Results show that our intermediate perception increases the accuracy by 20% than the direct prediction. Our model generalizes well to other public indoor datasets and is also demonstrated for robot flights in simulation and experiments.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 21:55:07 GMT" } ]
2017-05-01T00:00:00
[ [ "Yang", "Shichao", "" ], [ "Konam", "Sandeep", "" ], [ "Ma", "Chen", "" ], [ "Rosenthal", "Stephanie", "" ], [ "Veloso", "Manuela", "" ], [ "Scherer", "Sebastian", "" ] ]
TITLE: Obstacle Avoidance through Deep Networks based Intermediate Perception ABSTRACT: Obstacle avoidance from monocular images is a challenging problem for robots. Though multi-view structure-from-motion could build 3D maps, it is not robust in textureless environments. Some learning based methods exploit human demonstration to predict a steering command directly from a single image. However, this method is usually biased towards certain tasks or demonstration scenarios and also biased by human understanding. In this paper, we propose a new method to predict a trajectory from images. We train our system on more diverse NYUv2 dataset. The ground truth trajectory is computed from the designed cost functions automatically. The Convolutional Neural Network perception is divided into two stages: first, predict depth map and surface normal from RGB images, which are two important geometric properties related to 3D obstacle representation. Second, predict the trajectory from the depth and normal. Results show that our intermediate perception increases the accuracy by 20% than the direct prediction. Our model generalizes well to other public indoor datasets and is also demonstrated for robot flights in simulation and experiments.
no_new_dataset
0.952175
1704.08763
Erroll Wood
Erroll Wood, Tadas Baltrusaitis, Louis-Philippe Morency, Peter Robinson, Andreas Bulling
GazeDirector: Fully Articulated Eye Gaze Redirection in Video
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present GazeDirector, a new approach for eye gaze redirection that uses model-fitting. Our method first tracks the eyes by fitting a multi-part eye region model to video frames using analysis-by-synthesis, thereby recovering eye region shape, texture, pose, and gaze simultaneously. It then redirects gaze by 1) warping the eyelids from the original image using a model-derived flow field, and 2) rendering and compositing synthesized 3D eyeballs onto the output image in a photorealistic manner. GazeDirector allows us to change where people are looking without person-specific training data, and with full articulation, i.e. we can precisely specify new gaze directions in 3D. Quantitatively, we evaluate both model-fitting and gaze synthesis, with experiments for gaze estimation and redirection on the Columbia gaze dataset. Qualitatively, we compare GazeDirector against recent work on gaze redirection, showing better results especially for large redirection angles. Finally, we demonstrate gaze redirection on YouTube videos by introducing new 3D gaze targets and by manipulating visual behavior.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 22:23:53 GMT" } ]
2017-05-01T00:00:00
[ [ "Wood", "Erroll", "" ], [ "Baltrusaitis", "Tadas", "" ], [ "Morency", "Louis-Philippe", "" ], [ "Robinson", "Peter", "" ], [ "Bulling", "Andreas", "" ] ]
TITLE: GazeDirector: Fully Articulated Eye Gaze Redirection in Video ABSTRACT: We present GazeDirector, a new approach for eye gaze redirection that uses model-fitting. Our method first tracks the eyes by fitting a multi-part eye region model to video frames using analysis-by-synthesis, thereby recovering eye region shape, texture, pose, and gaze simultaneously. It then redirects gaze by 1) warping the eyelids from the original image using a model-derived flow field, and 2) rendering and compositing synthesized 3D eyeballs onto the output image in a photorealistic manner. GazeDirector allows us to change where people are looking without person-specific training data, and with full articulation, i.e. we can precisely specify new gaze directions in 3D. Quantitatively, we evaluate both model-fitting and gaze synthesis, with experiments for gaze estimation and redirection on the Columbia gaze dataset. Qualitatively, we compare GazeDirector against recent work on gaze redirection, showing better results especially for large redirection angles. Finally, we demonstrate gaze redirection on YouTube videos by introducing new 3D gaze targets and by manipulating visual behavior.
no_new_dataset
0.953101
1704.08812
Xiaoyong Shen
Xiaoyong Shen, Ruixing Wang, Hengshuang Zhao, Jiaya Jia
Automatic Real-time Background Cut for Portrait Videos
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We in this paper solve the problem of high-quality automatic real-time background cut for 720p portrait videos. We first handle the background ambiguity issue in semantic segmentation by proposing a global background attenuation model. A spatial-temporal refinement network is developed to further refine the segmentation errors in each frame and ensure temporal coherence in the segmentation map. We form an end-to-end network for training and testing. Each module is designed considering efficiency and accuracy. We build a portrait dataset, which includes 8,000 images with high-quality labeled map for training and testing. To further improve the performance, we build a portrait video dataset with 50 sequences to fine-tune video segmentation. Our framework benefits many video processing applications.
[ { "version": "v1", "created": "Fri, 28 Apr 2017 05:29:34 GMT" } ]
2017-05-01T00:00:00
[ [ "Shen", "Xiaoyong", "" ], [ "Wang", "Ruixing", "" ], [ "Zhao", "Hengshuang", "" ], [ "Jia", "Jiaya", "" ] ]
TITLE: Automatic Real-time Background Cut for Portrait Videos ABSTRACT: We in this paper solve the problem of high-quality automatic real-time background cut for 720p portrait videos. We first handle the background ambiguity issue in semantic segmentation by proposing a global background attenuation model. A spatial-temporal refinement network is developed to further refine the segmentation errors in each frame and ensure temporal coherence in the segmentation map. We form an end-to-end network for training and testing. Each module is designed considering efficiency and accuracy. We build a portrait dataset, which includes 8,000 images with high-quality labeled map for training and testing. To further improve the performance, we build a portrait video dataset with 50 sequences to fine-tune video segmentation. Our framework benefits many video processing applications.
new_dataset
0.950824
1704.08818
Yong Xia
Benteng Ma, Yong Xia
A Tribe Competition-Based Genetic Algorithm for Feature Selection in Pattern Classification
null
null
10.1016/j.asoc.2017.04.042
null
cs.LG cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Feature selection has always been a critical step in pattern recognition, in which evolutionary algorithms, such as the genetic algorithm (GA), are most commonly used. However, the individual encoding scheme used in various GAs would either pose a bias on the solution or require a pre-specified number of features, and hence may lead to less accurate results. In this paper, a tribe competition-based genetic algorithm (TCbGA) is proposed for feature selection in pattern classification. The population of individuals is divided into multiple tribes, and the initialization and evolutionary operations are modified to ensure that the number of selected features in each tribe follows a Gaussian distribution. Thus each tribe focuses on exploring a specific part of the solution space. Meanwhile, tribe competition is introduced to the evolution process, which allows the winning tribes, which produce better individuals, to enlarge their sizes, i.e. having more individuals to search their parts of the solution space. This algorithm, therefore, avoids the bias on solutions and requirement of a pre-specified number of features. We have evaluated our algorithm against several state-of-the-art feature selection approaches on 20 benchmark datasets. Our results suggest that the proposed TCbGA algorithm can identify the optimal feature subset more effectively and produce more accurate pattern classification.
[ { "version": "v1", "created": "Fri, 28 Apr 2017 06:25:50 GMT" } ]
2017-05-01T00:00:00
[ [ "Ma", "Benteng", "" ], [ "Xia", "Yong", "" ] ]
TITLE: A Tribe Competition-Based Genetic Algorithm for Feature Selection in Pattern Classification ABSTRACT: Feature selection has always been a critical step in pattern recognition, in which evolutionary algorithms, such as the genetic algorithm (GA), are most commonly used. However, the individual encoding scheme used in various GAs would either pose a bias on the solution or require a pre-specified number of features, and hence may lead to less accurate results. In this paper, a tribe competition-based genetic algorithm (TCbGA) is proposed for feature selection in pattern classification. The population of individuals is divided into multiple tribes, and the initialization and evolutionary operations are modified to ensure that the number of selected features in each tribe follows a Gaussian distribution. Thus each tribe focuses on exploring a specific part of the solution space. Meanwhile, tribe competition is introduced to the evolution process, which allows the winning tribes, which produce better individuals, to enlarge their sizes, i.e. having more individuals to search their parts of the solution space. This algorithm, therefore, avoids the bias on solutions and requirement of a pre-specified number of features. We have evaluated our algorithm against several state-of-the-art feature selection approaches on 20 benchmark datasets. Our results suggest that the proposed TCbGA algorithm can identify the optimal feature subset more effectively and produce more accurate pattern classification.
no_new_dataset
0.950411
1704.08853
Tieyun Qian
Bei Liu, Tieyun Qian, Bing Liu, Liang Hong, Zhenni You, Yuxiang Li
Learning Spatiotemporal-Aware Representation for POI Recommendation
null
null
null
null
cs.IR cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The wide spread of location-based social networks brings about a huge volume of user check-in data, which facilitates the recommendation of points of interest (POIs). Recent advances on distributed representation shed light on learning low dimensional dense vectors to alleviate the data sparsity problem. Current studies on representation learning for POI recommendation embed both users and POIs in a common latent space, and users' preference is inferred based on the distance/similarity between a user and a POI. Such an approach is not in accordance with the semantics of users and POIs as they are inherently different objects. In this paper, we present a novel spatiotemporal aware (STA) representation, which models the spatial and temporal information as \emph{a relationship connecting users and POIs}. Our model generalizes the recent advances in knowledge graph embedding. The basic idea is that the embedding of a $<$time, location$>$ pair corresponds to a translation from embeddings of users to POIs. Since the POI embedding should be close to the user embedding plus the relationship vector, the recommendation can be performed by selecting the top-\emph{k} POIs similar to the translated POI, which are all of the same type of objects. We conduct extensive experiments on two real-world datasets. The results demonstrate that our STA model achieves the state-of-the-art performance in terms of high recommendation accuracy, robustness to data sparsity and effectiveness in handling cold start problem.
[ { "version": "v1", "created": "Fri, 28 Apr 2017 09:01:01 GMT" } ]
2017-05-01T00:00:00
[ [ "Liu", "Bei", "" ], [ "Qian", "Tieyun", "" ], [ "Liu", "Bing", "" ], [ "Hong", "Liang", "" ], [ "You", "Zhenni", "" ], [ "Li", "Yuxiang", "" ] ]
TITLE: Learning Spatiotemporal-Aware Representation for POI Recommendation ABSTRACT: The wide spread of location-based social networks brings about a huge volume of user check-in data, which facilitates the recommendation of points of interest (POIs). Recent advances on distributed representation shed light on learning low dimensional dense vectors to alleviate the data sparsity problem. Current studies on representation learning for POI recommendation embed both users and POIs in a common latent space, and users' preference is inferred based on the distance/similarity between a user and a POI. Such an approach is not in accordance with the semantics of users and POIs as they are inherently different objects. In this paper, we present a novel spatiotemporal aware (STA) representation, which models the spatial and temporal information as \emph{a relationship connecting users and POIs}. Our model generalizes the recent advances in knowledge graph embedding. The basic idea is that the embedding of a $<$time, location$>$ pair corresponds to a translation from embeddings of users to POIs. Since the POI embedding should be close to the user embedding plus the relationship vector, the recommendation can be performed by selecting the top-\emph{k} POIs similar to the translated POI, which are all of the same type of objects. We conduct extensive experiments on two real-world datasets. The results demonstrate that our STA model achieves the state-of-the-art performance in terms of high recommendation accuracy, robustness to data sparsity and effectiveness in handling cold start problem.
no_new_dataset
0.949153
1704.08881
Christian Eggert
Christian Eggert, Dan Zecha, Stephan Brehm, Rainer Lienhart
Improving Small Object Proposals for Company Logo Detection
8 Pages, ICMR 2017
null
10.1145/3078971.3078990
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many modern approaches for object detection are two-staged pipelines. The first stage identifies regions of interest which are then classified in the second stage. Faster R-CNN is such an approach for object detection which combines both stages into a single pipeline. In this paper we apply Faster R-CNN to the task of company logo detection. Motivated by its weak performance on small object instances, we examine in detail both the proposal and the classification stage with respect to a wide range of object sizes. We investigate the influence of feature map resolution on the performance of those stages. Based on theoretical considerations, we introduce an improved scheme for generating anchor proposals and propose a modification to Faster R-CNN which leverages higher-resolution feature maps for small objects. We evaluate our approach on the FlickrLogos dataset improving the RPN performance from 0.52 to 0.71 (MABO) and the detection performance from 0.52 to 0.67 (mAP).
[ { "version": "v1", "created": "Fri, 28 Apr 2017 11:30:10 GMT" } ]
2017-05-01T00:00:00
[ [ "Eggert", "Christian", "" ], [ "Zecha", "Dan", "" ], [ "Brehm", "Stephan", "" ], [ "Lienhart", "Rainer", "" ] ]
TITLE: Improving Small Object Proposals for Company Logo Detection ABSTRACT: Many modern approaches for object detection are two-staged pipelines. The first stage identifies regions of interest which are then classified in the second stage. Faster R-CNN is such an approach for object detection which combines both stages into a single pipeline. In this paper we apply Faster R-CNN to the task of company logo detection. Motivated by its weak performance on small object instances, we examine in detail both the proposal and the classification stage with respect to a wide range of object sizes. We investigate the influence of feature map resolution on the performance of those stages. Based on theoretical considerations, we introduce an improved scheme for generating anchor proposals and propose a modification to Faster R-CNN which leverages higher-resolution feature maps for small objects. We evaluate our approach on the FlickrLogos dataset improving the RPN performance from 0.52 to 0.71 (MABO) and the detection performance from 0.52 to 0.67 (mAP).
no_new_dataset
0.949856
1704.08950
Amit Kumar
Amit Kumar, Rahul Dutta, Harbhajan Rai
Intelligent Personal Assistant with Knowledge Navigation
Converted O(N3) solution to viable O(N) solution
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An Intelligent Personal Agent (IPA) is an agent that has the purpose of helping the user to gain information through reliable resources with the help of knowledge navigation techniques and saving time to search the best content. The agent is also responsible for responding to the chat-based queries with the help of Conversation Corpus. We will be testing different methods for optimal query generation. To felicitate the ease of usage of the application, the agent will be able to accept the input through Text (Keyboard), Voice (Speech Recognition) and Server (Facebook) and output responses using the same method. Existing chat bots reply by making changes in the input, but we will give responses based on multiple SRT files. The model will learn using the human dialogs dataset and will be able respond human-like. Responses to queries about famous things (places, people, and words) can be provided using web scraping which will enable the bot to have knowledge navigation features. The agent will even learn from its past experiences supporting semi-supervised learning.
[ { "version": "v1", "created": "Fri, 28 Apr 2017 14:26:12 GMT" } ]
2017-05-01T00:00:00
[ [ "Kumar", "Amit", "" ], [ "Dutta", "Rahul", "" ], [ "Rai", "Harbhajan", "" ] ]
TITLE: Intelligent Personal Assistant with Knowledge Navigation ABSTRACT: An Intelligent Personal Agent (IPA) is an agent that has the purpose of helping the user to gain information through reliable resources with the help of knowledge navigation techniques and saving time to search the best content. The agent is also responsible for responding to the chat-based queries with the help of Conversation Corpus. We will be testing different methods for optimal query generation. To felicitate the ease of usage of the application, the agent will be able to accept the input through Text (Keyboard), Voice (Speech Recognition) and Server (Facebook) and output responses using the same method. Existing chat bots reply by making changes in the input, but we will give responses based on multiple SRT files. The model will learn using the human dialogs dataset and will be able respond human-like. Responses to queries about famous things (places, people, and words) can be provided using web scraping which will enable the bot to have knowledge navigation features. The agent will even learn from its past experiences supporting semi-supervised learning.
no_new_dataset
0.938688
1512.09049
Chenliang Xu
Chenliang Xu and Jason J. Corso
LIBSVX: A Supervoxel Library and Benchmark for Early Video Processing
In Review at International Journal of Computer Vision
Int J Comput Vis (2016) 119: 272
10.1007/s11263-016-0906-5
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Supervoxel segmentation has strong potential to be incorporated into early video analysis as superpixel segmentation has in image analysis. However, there are many plausible supervoxel methods and little understanding as to when and where each is most appropriate. Indeed, we are not aware of a single comparative study on supervoxel segmentation. To that end, we study seven supervoxel algorithms, including both off-line and streaming methods, in the context of what we consider to be a good supervoxel: namely, spatiotemporal uniformity, object/region boundary detection, region compression and parsimony. For the evaluation we propose a comprehensive suite of seven quality metrics to measure these desirable supervoxel characteristics. In addition, we evaluate the methods in a supervoxel classification task as a proxy for subsequent high-level uses of the supervoxels in video analysis. We use six existing benchmark video datasets with a variety of content-types and dense human annotations. Our findings have led us to conclusive evidence that the hierarchical graph-based (GBH), segmentation by weighted aggregation (SWA) and temporal superpixels (TSP) methods are the top-performers among the seven methods. They all perform well in terms of segmentation accuracy, but vary in regard to the other desiderata: GBH captures object boundaries best; SWA has the best potential for region compression; and TSP achieves the best undersegmentation error.
[ { "version": "v1", "created": "Wed, 30 Dec 2015 18:25:19 GMT" } ]
2017-04-28T00:00:00
[ [ "Xu", "Chenliang", "" ], [ "Corso", "Jason J.", "" ] ]
TITLE: LIBSVX: A Supervoxel Library and Benchmark for Early Video Processing ABSTRACT: Supervoxel segmentation has strong potential to be incorporated into early video analysis as superpixel segmentation has in image analysis. However, there are many plausible supervoxel methods and little understanding as to when and where each is most appropriate. Indeed, we are not aware of a single comparative study on supervoxel segmentation. To that end, we study seven supervoxel algorithms, including both off-line and streaming methods, in the context of what we consider to be a good supervoxel: namely, spatiotemporal uniformity, object/region boundary detection, region compression and parsimony. For the evaluation we propose a comprehensive suite of seven quality metrics to measure these desirable supervoxel characteristics. In addition, we evaluate the methods in a supervoxel classification task as a proxy for subsequent high-level uses of the supervoxels in video analysis. We use six existing benchmark video datasets with a variety of content-types and dense human annotations. Our findings have led us to conclusive evidence that the hierarchical graph-based (GBH), segmentation by weighted aggregation (SWA) and temporal superpixels (TSP) methods are the top-performers among the seven methods. They all perform well in terms of segmentation accuracy, but vary in regard to the other desiderata: GBH captures object boundaries best; SWA has the best potential for region compression; and TSP achieves the best undersegmentation error.
no_new_dataset
0.939582
1604.00494
Phi Vu Tran
Phi Vu Tran
A Fully Convolutional Neural Network for Cardiac Segmentation in Short-Axis MRI
Initial Technical Report; Include link to models and code
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Automated cardiac segmentation from magnetic resonance imaging datasets is an essential step in the timely diagnosis and management of cardiac pathologies. We propose to tackle the problem of automated left and right ventricle segmentation through the application of a deep fully convolutional neural network architecture. Our model is efficiently trained end-to-end in a single learning stage from whole-image inputs and ground truths to make inference at every pixel. To our knowledge, this is the first application of a fully convolutional neural network architecture for pixel-wise labeling in cardiac magnetic resonance imaging. Numerical experiments demonstrate that our model is robust to outperform previous fully automated methods across multiple evaluation measures on a range of cardiac datasets. Moreover, our model is fast and can leverage commodity compute resources such as the graphics processing unit to enable state-of-the-art cardiac segmentation at massive scales. The models and code are available at https://github.com/vuptran/cardiac-segmentation
[ { "version": "v1", "created": "Sat, 2 Apr 2016 12:32:55 GMT" }, { "version": "v2", "created": "Wed, 26 Apr 2017 10:11:34 GMT" }, { "version": "v3", "created": "Thu, 27 Apr 2017 03:04:26 GMT" } ]
2017-04-28T00:00:00
[ [ "Tran", "Phi Vu", "" ] ]
TITLE: A Fully Convolutional Neural Network for Cardiac Segmentation in Short-Axis MRI ABSTRACT: Automated cardiac segmentation from magnetic resonance imaging datasets is an essential step in the timely diagnosis and management of cardiac pathologies. We propose to tackle the problem of automated left and right ventricle segmentation through the application of a deep fully convolutional neural network architecture. Our model is efficiently trained end-to-end in a single learning stage from whole-image inputs and ground truths to make inference at every pixel. To our knowledge, this is the first application of a fully convolutional neural network architecture for pixel-wise labeling in cardiac magnetic resonance imaging. Numerical experiments demonstrate that our model is robust to outperform previous fully automated methods across multiple evaluation measures on a range of cardiac datasets. Moreover, our model is fast and can leverage commodity compute resources such as the graphics processing unit to enable state-of-the-art cardiac segmentation at massive scales. The models and code are available at https://github.com/vuptran/cardiac-segmentation
no_new_dataset
0.951504
1610.01239
Qinglong Wang
Qinglong Wang, Wenbo Guo, Kaixuan Zhang, Alexander G. Ororbia II, Xinyu Xing, C. Lee Giles, Xue Liu
Adversary Resistant Deep Neural Networks with an Application to Malware Detection
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Beyond its highly publicized victories in Go, there have been numerous successful applications of deep learning in information retrieval, computer vision and speech recognition. In cybersecurity, an increasing number of companies have become excited about the potential of deep learning, and have started to use it for various security incidents, the most popular being malware detection. These companies assert that deep learning (DL) could help turn the tide in the battle against malware infections. However, deep neural networks (DNNs) are vulnerable to adversarial samples, a flaw that plagues most if not all statistical learning models. Recent research has demonstrated that those with malicious intent can easily circumvent deep learning-powered malware detection by exploiting this flaw. In order to address this problem, previous work has developed various defense mechanisms that either augmenting training data or enhance model's complexity. However, after a thorough analysis of the fundamental flaw in DNNs, we discover that the effectiveness of current defenses is limited and, more importantly, cannot provide theoretical guarantees as to their robustness against adversarial sampled-based attacks. As such, we propose a new adversary resistant technique that obstructs attackers from constructing impactful adversarial samples by randomly nullifying features within samples. In this work, we evaluate our proposed technique against a real world dataset with 14,679 malware variants and 17,399 benign programs. We theoretically validate the robustness of our technique, and empirically show that our technique significantly boosts DNN robustness to adversarial samples while maintaining high accuracy in classification. To demonstrate the general applicability of our proposed method, we also conduct experiments using the MNIST and CIFAR-10 datasets, generally used in image recognition research.
[ { "version": "v1", "created": "Wed, 5 Oct 2016 00:46:03 GMT" }, { "version": "v2", "created": "Thu, 6 Oct 2016 16:20:56 GMT" }, { "version": "v3", "created": "Fri, 7 Oct 2016 17:24:13 GMT" }, { "version": "v4", "created": "Thu, 27 Apr 2017 17:25:30 GMT" } ]
2017-04-28T00:00:00
[ [ "Wang", "Qinglong", "" ], [ "Guo", "Wenbo", "" ], [ "Zhang", "Kaixuan", "" ], [ "Ororbia", "Alexander G.", "II" ], [ "Xing", "Xinyu", "" ], [ "Giles", "C. Lee", "" ], [ "Liu", "Xue", "" ] ]
TITLE: Adversary Resistant Deep Neural Networks with an Application to Malware Detection ABSTRACT: Beyond its highly publicized victories in Go, there have been numerous successful applications of deep learning in information retrieval, computer vision and speech recognition. In cybersecurity, an increasing number of companies have become excited about the potential of deep learning, and have started to use it for various security incidents, the most popular being malware detection. These companies assert that deep learning (DL) could help turn the tide in the battle against malware infections. However, deep neural networks (DNNs) are vulnerable to adversarial samples, a flaw that plagues most if not all statistical learning models. Recent research has demonstrated that those with malicious intent can easily circumvent deep learning-powered malware detection by exploiting this flaw. In order to address this problem, previous work has developed various defense mechanisms that either augmenting training data or enhance model's complexity. However, after a thorough analysis of the fundamental flaw in DNNs, we discover that the effectiveness of current defenses is limited and, more importantly, cannot provide theoretical guarantees as to their robustness against adversarial sampled-based attacks. As such, we propose a new adversary resistant technique that obstructs attackers from constructing impactful adversarial samples by randomly nullifying features within samples. In this work, we evaluate our proposed technique against a real world dataset with 14,679 malware variants and 17,399 benign programs. We theoretically validate the robustness of our technique, and empirically show that our technique significantly boosts DNN robustness to adversarial samples while maintaining high accuracy in classification. To demonstrate the general applicability of our proposed method, we also conduct experiments using the MNIST and CIFAR-10 datasets, generally used in image recognition research.
no_new_dataset
0.933127
1612.01105
Hengshuang Zhao
Hengshuang Zhao, Jianping Shi, Xiaojuan Qi, Xiaogang Wang, Jiaya Jia
Pyramid Scene Parsing Network
CVPR 2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Scene parsing is challenging for unrestricted open vocabulary and diverse scenes. In this paper, we exploit the capability of global context information by different-region-based context aggregation through our pyramid pooling module together with the proposed pyramid scene parsing network (PSPNet). Our global prior representation is effective to produce good quality results on the scene parsing task, while PSPNet provides a superior framework for pixel-level prediction tasks. The proposed approach achieves state-of-the-art performance on various datasets. It came first in ImageNet scene parsing challenge 2016, PASCAL VOC 2012 benchmark and Cityscapes benchmark. A single PSPNet yields new record of mIoU accuracy 85.4% on PASCAL VOC 2012 and accuracy 80.2% on Cityscapes.
[ { "version": "v1", "created": "Sun, 4 Dec 2016 11:46:22 GMT" }, { "version": "v2", "created": "Thu, 27 Apr 2017 12:15:17 GMT" } ]
2017-04-28T00:00:00
[ [ "Zhao", "Hengshuang", "" ], [ "Shi", "Jianping", "" ], [ "Qi", "Xiaojuan", "" ], [ "Wang", "Xiaogang", "" ], [ "Jia", "Jiaya", "" ] ]
TITLE: Pyramid Scene Parsing Network ABSTRACT: Scene parsing is challenging for unrestricted open vocabulary and diverse scenes. In this paper, we exploit the capability of global context information by different-region-based context aggregation through our pyramid pooling module together with the proposed pyramid scene parsing network (PSPNet). Our global prior representation is effective to produce good quality results on the scene parsing task, while PSPNet provides a superior framework for pixel-level prediction tasks. The proposed approach achieves state-of-the-art performance on various datasets. It came first in ImageNet scene parsing challenge 2016, PASCAL VOC 2012 benchmark and Cityscapes benchmark. A single PSPNet yields new record of mIoU accuracy 85.4% on PASCAL VOC 2012 and accuracy 80.2% on Cityscapes.
no_new_dataset
0.953188
1704.04008
Afshin Rahimi
Afshin Rahimi, Trevor Cohn, Timothy Baldwin
A Neural Model for User Geolocation and Lexical Dialectology
null
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a simple yet effective text- based user geolocation model based on a neural network with one hidden layer, which achieves state of the art performance over three Twitter benchmark geolocation datasets, in addition to producing word and phrase embeddings in the hidden layer that we show to be useful for detecting dialectal terms. As part of our analysis of dialectal terms, we release DAREDS, a dataset for evaluating dialect term detection methods.
[ { "version": "v1", "created": "Thu, 13 Apr 2017 06:35:55 GMT" }, { "version": "v2", "created": "Thu, 20 Apr 2017 00:38:27 GMT" }, { "version": "v3", "created": "Thu, 27 Apr 2017 01:18:58 GMT" } ]
2017-04-28T00:00:00
[ [ "Rahimi", "Afshin", "" ], [ "Cohn", "Trevor", "" ], [ "Baldwin", "Timothy", "" ] ]
TITLE: A Neural Model for User Geolocation and Lexical Dialectology ABSTRACT: We propose a simple yet effective text- based user geolocation model based on a neural network with one hidden layer, which achieves state of the art performance over three Twitter benchmark geolocation datasets, in addition to producing word and phrase embeddings in the hidden layer that we show to be useful for detecting dialectal terms. As part of our analysis of dialectal terms, we release DAREDS, a dataset for evaluating dialect term detection methods.
new_dataset
0.957991
1704.05588
Dhiraj Gandhi
Dhiraj Gandhi, Lerrel Pinto, Abhinav Gupta
Learning to Fly by Crashing
null
null
null
null
cs.RO cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
How do you learn to navigate an Unmanned Aerial Vehicle (UAV) and avoid obstacles? One approach is to use a small dataset collected by human experts: however, high capacity learning algorithms tend to overfit when trained with little data. An alternative is to use simulation. But the gap between simulation and real world remains large especially for perception problems. The reason most research avoids using large-scale real data is the fear of crashes! In this paper, we propose to bite the bullet and collect a dataset of crashes itself! We build a drone whose sole purpose is to crash into objects: it samples naive trajectories and crashes into random objects. We crash our drone 11,500 times to create one of the biggest UAV crash dataset. This dataset captures the different ways in which a UAV can crash. We use all this negative flying data in conjunction with positive data sampled from the same trajectories to learn a simple yet powerful policy for UAV navigation. We show that this simple self-supervised model is quite effective in navigating the UAV even in extremely cluttered environments with dynamic obstacles including humans. For supplementary video see: https://youtu.be/u151hJaGKUo
[ { "version": "v1", "created": "Wed, 19 Apr 2017 02:20:20 GMT" }, { "version": "v2", "created": "Thu, 27 Apr 2017 00:13:19 GMT" } ]
2017-04-28T00:00:00
[ [ "Gandhi", "Dhiraj", "" ], [ "Pinto", "Lerrel", "" ], [ "Gupta", "Abhinav", "" ] ]
TITLE: Learning to Fly by Crashing ABSTRACT: How do you learn to navigate an Unmanned Aerial Vehicle (UAV) and avoid obstacles? One approach is to use a small dataset collected by human experts: however, high capacity learning algorithms tend to overfit when trained with little data. An alternative is to use simulation. But the gap between simulation and real world remains large especially for perception problems. The reason most research avoids using large-scale real data is the fear of crashes! In this paper, we propose to bite the bullet and collect a dataset of crashes itself! We build a drone whose sole purpose is to crash into objects: it samples naive trajectories and crashes into random objects. We crash our drone 11,500 times to create one of the biggest UAV crash dataset. This dataset captures the different ways in which a UAV can crash. We use all this negative flying data in conjunction with positive data sampled from the same trajectories to learn a simple yet powerful policy for UAV navigation. We show that this simple self-supervised model is quite effective in navigating the UAV even in extremely cluttered environments with dynamic obstacles including humans. For supplementary video see: https://youtu.be/u151hJaGKUo
new_dataset
0.957358
1704.08292
Chenliang Xu
Lele Chen, Sudhanshu Srivastava, Zhiyao Duan and Chenliang Xu
Deep Cross-Modal Audio-Visual Generation
null
null
null
null
cs.CV cs.MM cs.SD
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cross-modal audio-visual perception has been a long-lasting topic in psychology and neurology, and various studies have discovered strong correlations in human perception of auditory and visual stimuli. Despite works in computational multimodal modeling, the problem of cross-modal audio-visual generation has not been systematically studied in the literature. In this paper, we make the first attempt to solve this cross-modal generation problem leveraging the power of deep generative adversarial training. Specifically, we use conditional generative adversarial networks to achieve cross-modal audio-visual generation of musical performances. We explore different encoding methods for audio and visual signals, and work on two scenarios: instrument-oriented generation and pose-oriented generation. Being the first to explore this new problem, we compose two new datasets with pairs of images and sounds of musical performances of different instruments. Our experiments using both classification and human evaluations demonstrate that our model has the ability to generate one modality, i.e., audio/visual, from the other modality, i.e., visual/audio, to a good extent. Our experiments on various design choices along with the datasets will facilitate future research in this new problem space.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 18:46:10 GMT" } ]
2017-04-28T00:00:00
[ [ "Chen", "Lele", "" ], [ "Srivastava", "Sudhanshu", "" ], [ "Duan", "Zhiyao", "" ], [ "Xu", "Chenliang", "" ] ]
TITLE: Deep Cross-Modal Audio-Visual Generation ABSTRACT: Cross-modal audio-visual perception has been a long-lasting topic in psychology and neurology, and various studies have discovered strong correlations in human perception of auditory and visual stimuli. Despite works in computational multimodal modeling, the problem of cross-modal audio-visual generation has not been systematically studied in the literature. In this paper, we make the first attempt to solve this cross-modal generation problem leveraging the power of deep generative adversarial training. Specifically, we use conditional generative adversarial networks to achieve cross-modal audio-visual generation of musical performances. We explore different encoding methods for audio and visual signals, and work on two scenarios: instrument-oriented generation and pose-oriented generation. Being the first to explore this new problem, we compose two new datasets with pairs of images and sounds of musical performances of different instruments. Our experiments using both classification and human evaluations demonstrate that our model has the ability to generate one modality, i.e., audio/visual, from the other modality, i.e., visual/audio, to a good extent. Our experiments on various design choices along with the datasets will facilitate future research in this new problem space.
new_dataset
0.95594
1704.08331
Narapureddy Dinesh Reddy
Nazrul Haque, N Dinesh Reddy and K. Madhava Krishna
Joint Semantic and Motion Segmentation for dynamic scenes using Deep Convolutional Networks
In Proceedings of the 12th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications - Volume 5: Visapp, (Visigrapp 2017)
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Dynamic scene understanding is a challenging problem and motion segmentation plays a crucial role in solving it. Incorporating semantics and motion enhances the overall perception of the dynamic scene. For applications of outdoor robotic navigation, joint learning methods have not been extensively used for extracting spatio-temporal features or adding different priors into the formulation. The task becomes even more challenging without stereo information being incorporated. This paper proposes an approach to fuse semantic features and motion clues using CNNs, to address the problem of monocular semantic motion segmentation. We deduce semantic and motion labels by integrating optical flow as a constraint with semantic features into dilated convolution network. The pipeline consists of three main stages i.e Feature extraction, Feature amplification and Multi Scale Context Aggregation to fuse the semantics and flow features. Our joint formulation shows significant improvements in monocular motion segmentation over the state of the art methods on challenging KITTI tracking dataset.
[ { "version": "v1", "created": "Tue, 18 Apr 2017 03:06:03 GMT" } ]
2017-04-28T00:00:00
[ [ "Haque", "Nazrul", "" ], [ "Reddy", "N Dinesh", "" ], [ "Krishna", "K. Madhava", "" ] ]
TITLE: Joint Semantic and Motion Segmentation for dynamic scenes using Deep Convolutional Networks ABSTRACT: Dynamic scene understanding is a challenging problem and motion segmentation plays a crucial role in solving it. Incorporating semantics and motion enhances the overall perception of the dynamic scene. For applications of outdoor robotic navigation, joint learning methods have not been extensively used for extracting spatio-temporal features or adding different priors into the formulation. The task becomes even more challenging without stereo information being incorporated. This paper proposes an approach to fuse semantic features and motion clues using CNNs, to address the problem of monocular semantic motion segmentation. We deduce semantic and motion labels by integrating optical flow as a constraint with semantic features into dilated convolution network. The pipeline consists of three main stages i.e Feature extraction, Feature amplification and Multi Scale Context Aggregation to fuse the semantics and flow features. Our joint formulation shows significant improvements in monocular motion segmentation over the state of the art methods on challenging KITTI tracking dataset.
no_new_dataset
0.94699
1704.08345
Elyor Kodirov
Elyor Kodirov, Tao Xiang, Shaogang Gong
Semantic Autoencoder for Zero-Shot Learning
accepted to CVPR2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Existing zero-shot learning (ZSL) models typically learn a projection function from a feature space to a semantic embedding space (e.g.~attribute space). However, such a projection function is only concerned with predicting the training seen class semantic representation (e.g.~attribute prediction) or classification. When applied to test data, which in the context of ZSL contains different (unseen) classes without training data, a ZSL model typically suffers from the project domain shift problem. In this work, we present a novel solution to ZSL based on learning a Semantic AutoEncoder (SAE). Taking the encoder-decoder paradigm, an encoder aims to project a visual feature vector into the semantic space as in the existing ZSL models. However, the decoder exerts an additional constraint, that is, the projection/code must be able to reconstruct the original visual feature. We show that with this additional reconstruction constraint, the learned projection function from the seen classes is able to generalise better to the new unseen classes. Importantly, the encoder and decoder are linear and symmetric which enable us to develop an extremely efficient learning algorithm. Extensive experiments on six benchmark datasets demonstrate that the proposed SAE outperforms significantly the existing ZSL models with the additional benefit of lower computational cost. Furthermore, when the SAE is applied to supervised clustering problem, it also beats the state-of-the-art.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 20:45:53 GMT" } ]
2017-04-28T00:00:00
[ [ "Kodirov", "Elyor", "" ], [ "Xiang", "Tao", "" ], [ "Gong", "Shaogang", "" ] ]
TITLE: Semantic Autoencoder for Zero-Shot Learning ABSTRACT: Existing zero-shot learning (ZSL) models typically learn a projection function from a feature space to a semantic embedding space (e.g.~attribute space). However, such a projection function is only concerned with predicting the training seen class semantic representation (e.g.~attribute prediction) or classification. When applied to test data, which in the context of ZSL contains different (unseen) classes without training data, a ZSL model typically suffers from the project domain shift problem. In this work, we present a novel solution to ZSL based on learning a Semantic AutoEncoder (SAE). Taking the encoder-decoder paradigm, an encoder aims to project a visual feature vector into the semantic space as in the existing ZSL models. However, the decoder exerts an additional constraint, that is, the projection/code must be able to reconstruct the original visual feature. We show that with this additional reconstruction constraint, the learned projection function from the seen classes is able to generalise better to the new unseen classes. Importantly, the encoder and decoder are linear and symmetric which enable us to develop an extremely efficient learning algorithm. Extensive experiments on six benchmark datasets demonstrate that the proposed SAE outperforms significantly the existing ZSL models with the additional benefit of lower computational cost. Furthermore, when the SAE is applied to supervised clustering problem, it also beats the state-of-the-art.
no_new_dataset
0.944638
1704.08347
Jiachun Liao
Jiachun Liao, Lalitha Sankar, Vincent Y. F. Tan and Flavio P. Calmon
Hypothesis Testing under Mutual Information Privacy Constraints in the High Privacy Regime
13 pages, 7 figures. The paper is submitted to "Transactions on Information Forensics & Security". Comparing to the paper arXiv:1607.00533 "Hypothesis Testing in the High Privacy Limit", the overlapping content is results for binary hypothesis testing with a zero error exponent, and the extended contents are the results for both m-ary hypothesis testing and binary hypothesis testing with nonzero error exponents
null
null
null
cs.IT math.IT
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Hypothesis testing is a statistical inference framework for determining the true distribution among a set of possible distributions for a given dataset. Privacy restrictions may require the curator of the data or the respondents themselves to share data with the test only after applying a randomizing privacy mechanism. This work considers mutual information (MI) as the privacy metric for measuring leakage. In addition, motivated by the Chernoff-Stein lemma, the relative entropy between pairs of distributions of the output (generated by the privacy mechanism) is chosen as the utility metric. For these metrics, the goal is to find the optimal privacy-utility trade-off (PUT) and the corresponding optimal privacy mechanism for both binary and m-ary hypothesis testing. Focusing on the high privacy regime, Euclidean information-theoretic approximations of the binary and m-ary PUT problems are developed. The solutions for the approximation problems clarify that an MI-based privacy metric preserves the privacy of the source symbols in inverse proportion to their likelihoods.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 20:48:58 GMT" } ]
2017-04-28T00:00:00
[ [ "Liao", "Jiachun", "" ], [ "Sankar", "Lalitha", "" ], [ "Tan", "Vincent Y. F.", "" ], [ "Calmon", "Flavio P.", "" ] ]
TITLE: Hypothesis Testing under Mutual Information Privacy Constraints in the High Privacy Regime ABSTRACT: Hypothesis testing is a statistical inference framework for determining the true distribution among a set of possible distributions for a given dataset. Privacy restrictions may require the curator of the data or the respondents themselves to share data with the test only after applying a randomizing privacy mechanism. This work considers mutual information (MI) as the privacy metric for measuring leakage. In addition, motivated by the Chernoff-Stein lemma, the relative entropy between pairs of distributions of the output (generated by the privacy mechanism) is chosen as the utility metric. For these metrics, the goal is to find the optimal privacy-utility trade-off (PUT) and the corresponding optimal privacy mechanism for both binary and m-ary hypothesis testing. Focusing on the high privacy regime, Euclidean information-theoretic approximations of the binary and m-ary PUT problems are developed. The solutions for the approximation problems clarify that an MI-based privacy metric preserves the privacy of the source symbols in inverse proportion to their likelihoods.
no_new_dataset
0.950549
1704.08364
Eduardo Miqueles Dr.
Gilberto Martinez Jr., Janito V. Ferreira Filho, Eduardo X. Miqueles
Low-complexity Distributed Tomographic Backprojection for large datasets
null
null
null
null
cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this manuscript we present a fast GPU implementation for tomographic reconstruction of large datasets using data obtained at the Brazilian synchrotron light source. The algorithm is distributed in a cluster with 4 GPUs through a fast pipeline implemented in C programming language. Our algorithm is theoretically based on a recently discovered low complexity formula, computing the total volume within O(N3logN) floating point operations; much less than traditional algorithms that operates with O(N4) flops over an input data of size O(N3). The results obtained with real data indicate that a reconstruction can be achieved within 1 second provided the data is transferred completely to the memory.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 22:18:34 GMT" } ]
2017-04-28T00:00:00
[ [ "Martinez", "Gilberto", "Jr." ], [ "Filho", "Janito V. Ferreira", "" ], [ "Miqueles", "Eduardo X.", "" ] ]
TITLE: Low-complexity Distributed Tomographic Backprojection for large datasets ABSTRACT: In this manuscript we present a fast GPU implementation for tomographic reconstruction of large datasets using data obtained at the Brazilian synchrotron light source. The algorithm is distributed in a cluster with 4 GPUs through a fast pipeline implemented in C programming language. Our algorithm is theoretically based on a recently discovered low complexity formula, computing the total volume within O(N3logN) floating point operations; much less than traditional algorithms that operates with O(N4) flops over an input data of size O(N3). The results obtained with real data indicate that a reconstruction can be achieved within 1 second provided the data is transferred completely to the memory.
no_new_dataset
0.950641
1704.08378
Guanshuo Xu
Guanshuo Xu
Deep Convolutional Neural Network to Detect J-UNIWARD
Accepted by IH&MMSec 2017. This is a personal copy
null
null
null
cs.MM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents an empirical study on applying convolutional neural networks (CNNs) to detecting J-UNIWARD, one of the most secure JPEG steganographic method. Experiments guiding the architectural design of the CNNs have been conducted on the JPEG compressed BOSSBase containing 10,000 covers of size 512x512. Results have verified that both the pooling method and the depth of the CNNs are critical for performance. Results have also proved that a 20-layer CNN, in general, outperforms the most sophisticated feature-based methods, but its advantage gradually diminishes on hard-to-detect cases. To show that the performance generalizes to large-scale databases and to different cover sizes, one experiment has been conducted on the CLS-LOC dataset of ImageNet containing more than one million covers cropped to unified size of 256x256. The proposed 20-layer CNN has cut the error achieved by a CNN recently proposed for large-scale JPEG steganalysis by 35%. Source code is available via GitHub: https://github.com/GuanshuoXu/deep_cnn_jpeg_steganalysis
[ { "version": "v1", "created": "Wed, 26 Apr 2017 23:15:52 GMT" } ]
2017-04-28T00:00:00
[ [ "Xu", "Guanshuo", "" ] ]
TITLE: Deep Convolutional Neural Network to Detect J-UNIWARD ABSTRACT: This paper presents an empirical study on applying convolutional neural networks (CNNs) to detecting J-UNIWARD, one of the most secure JPEG steganographic method. Experiments guiding the architectural design of the CNNs have been conducted on the JPEG compressed BOSSBase containing 10,000 covers of size 512x512. Results have verified that both the pooling method and the depth of the CNNs are critical for performance. Results have also proved that a 20-layer CNN, in general, outperforms the most sophisticated feature-based methods, but its advantage gradually diminishes on hard-to-detect cases. To show that the performance generalizes to large-scale databases and to different cover sizes, one experiment has been conducted on the CLS-LOC dataset of ImageNet containing more than one million covers cropped to unified size of 256x256. The proposed 20-layer CNN has cut the error achieved by a CNN recently proposed for large-scale JPEG steganalysis by 35%. Source code is available via GitHub: https://github.com/GuanshuoXu/deep_cnn_jpeg_steganalysis
no_new_dataset
0.9463
1704.08384
Rajarshi Das
Rajarshi Das, Manzil Zaheer, Siva Reddy, Andrew McCallum
Question Answering on Knowledge Bases and Text using Universal Schema and Memory Networks
ACL 2017 (short)
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Existing question answering methods infer answers either from a knowledge base or from raw text. While knowledge base (KB) methods are good at answering compositional questions, their performance is often affected by the incompleteness of the KB. Au contraire, web text contains millions of facts that are absent in the KB, however in an unstructured form. {\it Universal schema} can support reasoning on the union of both structured KBs and unstructured text by aligning them in a common embedded space. In this paper we extend universal schema to natural language question answering, employing \emph{memory networks} to attend to the large body of facts in the combination of text and KB. Our models can be trained in an end-to-end fashion on question-answer pairs. Evaluation results on \spades fill-in-the-blank question answering dataset show that exploiting universal schema for question answering is better than using either a KB or text alone. This model also outperforms the current state-of-the-art by 8.5 $F_1$ points.\footnote{Code and data available in \url{https://rajarshd.github.io/TextKBQA}}
[ { "version": "v1", "created": "Thu, 27 Apr 2017 00:03:02 GMT" } ]
2017-04-28T00:00:00
[ [ "Das", "Rajarshi", "" ], [ "Zaheer", "Manzil", "" ], [ "Reddy", "Siva", "" ], [ "McCallum", "Andrew", "" ] ]
TITLE: Question Answering on Knowledge Bases and Text using Universal Schema and Memory Networks ABSTRACT: Existing question answering methods infer answers either from a knowledge base or from raw text. While knowledge base (KB) methods are good at answering compositional questions, their performance is often affected by the incompleteness of the KB. Au contraire, web text contains millions of facts that are absent in the KB, however in an unstructured form. {\it Universal schema} can support reasoning on the union of both structured KBs and unstructured text by aligning them in a common embedded space. In this paper we extend universal schema to natural language question answering, employing \emph{memory networks} to attend to the large body of facts in the combination of text and KB. Our models can be trained in an end-to-end fashion on question-answer pairs. Evaluation results on \spades fill-in-the-blank question answering dataset show that exploiting universal schema for question answering is better than using either a KB or text alone. This model also outperforms the current state-of-the-art by 8.5 $F_1$ points.\footnote{Code and data available in \url{https://rajarshd.github.io/TextKBQA}}
no_new_dataset
0.945399
1704.08509
Bo-Cheng Tsai
Yi-Hsin Chen, Wei-Yu Chen, Yu-Ting Chen, Bo-Cheng Tsai, Yu-Chiang Frank Wang, Min Sun
No More Discrimination: Cross City Adaptation of Road Scene Segmenters
13 pages, 10 figures
null
null
null
cs.CV cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Despite the recent success of deep-learning based semantic segmentation, deploying a pre-trained road scene segmenter to a city whose images are not presented in the training set would not achieve satisfactory performance due to dataset biases. Instead of collecting a large number of annotated images of each city of interest to train or refine the segmenter, we propose an unsupervised learning approach to adapt road scene segmenters across different cities. By utilizing Google Street View and its time-machine feature, we can collect unannotated images for each road scene at different times, so that the associated static-object priors can be extracted accordingly. By advancing a joint global and class-specific domain adversarial learning framework, adaptation of pre-trained segmenters to that city can be achieved without the need of any user annotation or interaction. We show that our method improves the performance of semantic segmentation in multiple cities across continents, while it performs favorably against state-of-the-art approaches requiring annotated training data.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 11:14:21 GMT" } ]
2017-04-28T00:00:00
[ [ "Chen", "Yi-Hsin", "" ], [ "Chen", "Wei-Yu", "" ], [ "Chen", "Yu-Ting", "" ], [ "Tsai", "Bo-Cheng", "" ], [ "Wang", "Yu-Chiang Frank", "" ], [ "Sun", "Min", "" ] ]
TITLE: No More Discrimination: Cross City Adaptation of Road Scene Segmenters ABSTRACT: Despite the recent success of deep-learning based semantic segmentation, deploying a pre-trained road scene segmenter to a city whose images are not presented in the training set would not achieve satisfactory performance due to dataset biases. Instead of collecting a large number of annotated images of each city of interest to train or refine the segmenter, we propose an unsupervised learning approach to adapt road scene segmenters across different cities. By utilizing Google Street View and its time-machine feature, we can collect unannotated images for each road scene at different times, so that the associated static-object priors can be extracted accordingly. By advancing a joint global and class-specific domain adversarial learning framework, adaptation of pre-trained segmenters to that city can be achieved without the need of any user annotation or interaction. We show that our method improves the performance of semantic segmentation in multiple cities across continents, while it performs favorably against state-of-the-art approaches requiring annotated training data.
no_new_dataset
0.946547
1704.08547
Benjamin Rubinstein
Chris Culnane, Benjamin I. P. Rubinstein, Vanessa Teague
Privacy Assessment of De-identified Opal Data: A report for Transport for NSW
14 pages, 3 figures, 4 tables
null
null
null
cs.CR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider the privacy implications of public release of a de-identified dataset of Opal card transactions. The data was recently published at https://opendata.transport.nsw.gov.au/dataset/opal-tap-on-and-tap-off. It consists of tap-on and tap-off counts for NSW's four modes of public transport, collected over two separate week-long periods. The data has been further treated to improve privacy by removing small counts, aggregating some stops and routes, and perturbing the counts. This is a summary of our findings.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 13:12:29 GMT" } ]
2017-04-28T00:00:00
[ [ "Culnane", "Chris", "" ], [ "Rubinstein", "Benjamin I. P.", "" ], [ "Teague", "Vanessa", "" ] ]
TITLE: Privacy Assessment of De-identified Opal Data: A report for Transport for NSW ABSTRACT: We consider the privacy implications of public release of a de-identified dataset of Opal card transactions. The data was recently published at https://opendata.transport.nsw.gov.au/dataset/opal-tap-on-and-tap-off. It consists of tap-on and tap-off counts for NSW's four modes of public transport, collected over two separate week-long periods. The data has been further treated to improve privacy by removing small counts, aggregating some stops and routes, and perturbing the counts. This is a summary of our findings.
new_dataset
0.838548
1704.08558
Nicola Prezza
Philip Bille, Inge Li G{\o}rtz, Nicola Prezza
Practical and Effective Re-Pair Compression
null
null
null
null
cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Re-Pair is an efficient grammar compressor that operates by recursively replacing high-frequency character pairs with new grammar symbols. The most space-efficient linear-time algorithm computing Re-Pair uses $(1+\epsilon)n+\sqrt n$ words on top of the re-writable text (of length $n$ and stored in $n$ words), for any constant $\epsilon>0$; in practice however, this solution uses complex sub-procedures preventing it from being practical. In this paper, we present an implementation of the above-mentioned result making use of more practical solutions; our tool further improves the working space to $(1.5+\epsilon)n$ words (text included), for some small constant $\epsilon$. As a second contribution, we focus on compact representations of the output grammar. The lower bound for storing a grammar with $d$ rules is $\log(d!)+2d\approx d\log d+0.557 d$ bits, and the most efficient encoding algorithm in the literature uses at most $d\log d + 2d$ bits and runs in $\mathcal O(d^{1.5})$ time. We describe a linear-time heuristic maximizing the compressibility of the output Re-Pair grammar. On real datasets, our grammar encoding uses---on average---only $2.8\%$ more bits than the information-theoretic minimum. In half of the tested cases, our compressor improves the output size of 7-Zip with maximum compression rate turned on.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 13:28:45 GMT" } ]
2017-04-28T00:00:00
[ [ "Bille", "Philip", "" ], [ "Gørtz", "Inge Li", "" ], [ "Prezza", "Nicola", "" ] ]
TITLE: Practical and Effective Re-Pair Compression ABSTRACT: Re-Pair is an efficient grammar compressor that operates by recursively replacing high-frequency character pairs with new grammar symbols. The most space-efficient linear-time algorithm computing Re-Pair uses $(1+\epsilon)n+\sqrt n$ words on top of the re-writable text (of length $n$ and stored in $n$ words), for any constant $\epsilon>0$; in practice however, this solution uses complex sub-procedures preventing it from being practical. In this paper, we present an implementation of the above-mentioned result making use of more practical solutions; our tool further improves the working space to $(1.5+\epsilon)n$ words (text included), for some small constant $\epsilon$. As a second contribution, we focus on compact representations of the output grammar. The lower bound for storing a grammar with $d$ rules is $\log(d!)+2d\approx d\log d+0.557 d$ bits, and the most efficient encoding algorithm in the literature uses at most $d\log d + 2d$ bits and runs in $\mathcal O(d^{1.5})$ time. We describe a linear-time heuristic maximizing the compressibility of the output Re-Pair grammar. On real datasets, our grammar encoding uses---on average---only $2.8\%$ more bits than the information-theoretic minimum. In half of the tested cases, our compressor improves the output size of 7-Zip with maximum compression rate turned on.
no_new_dataset
0.944125
1704.08628
Bastien Moysset
Bastien Moysset, Christopher Kermorvant, Christian Wolf
Full-Page Text Recognition: Learning Where to Start and When to Stop
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Text line detection and localization is a crucial step for full page document analysis, but still suffers from heterogeneity of real life documents. In this paper, we present a new approach for full page text recognition. Localization of the text lines is based on regressions with Fully Convolutional Neural Networks and Multidimensional Long Short-Term Memory as contextual layers. In order to increase the efficiency of this localization method, only the position of the left side of the text lines are predicted. The text recognizer is then in charge of predicting the end of the text to recognize. This method has shown good results for full page text recognition on the highly heterogeneous Maurdor dataset.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 15:50:37 GMT" } ]
2017-04-28T00:00:00
[ [ "Moysset", "Bastien", "" ], [ "Kermorvant", "Christopher", "" ], [ "Wolf", "Christian", "" ] ]
TITLE: Full-Page Text Recognition: Learning Where to Start and When to Stop ABSTRACT: Text line detection and localization is a crucial step for full page document analysis, but still suffers from heterogeneity of real life documents. In this paper, we present a new approach for full page text recognition. Localization of the text lines is based on regressions with Fully Convolutional Neural Networks and Multidimensional Long Short-Term Memory as contextual layers. In order to increase the efficiency of this localization method, only the position of the left side of the text lines are predicted. The text recognizer is then in charge of predicting the end of the text to recognize. This method has shown good results for full page text recognition on the highly heterogeneous Maurdor dataset.
no_new_dataset
0.951142
1704.08631
Nicolas Honnorat
Nicolas Honnorat, Christos Davatzikos
Sparse Hierachical Extrapolated Parametric Methods for Cortical Data Analysis
Technical report (ongoing work)
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Many neuroimaging studies focus on the cortex, in order to benefit from better signal to noise ratios and reduced computational burden. Cortical data are usually projected onto a reference mesh, where subsequent analyses are carried out. Several multiscale approaches have been proposed for analyzing these surface data, such as spherical harmonics and graph wavelets. As far as we know, however, the hierarchical structure of the template icosahedral meshes used by most neuroimaging software has never been exploited for cortical data factorization. In this paper, we demonstrate how the structure of the ubiquitous icosahedral meshes can be exploited by data factorization methods such as sparse dictionary learning, and we assess the optimization speed-up offered by extrapolation methods in this context. By testing different sparsity-inducing norms, extrapolation methods, and factorization schemes, we compare the performances of eleven methods for analyzing four datasets: two structural and two functional MRI datasets obtained by processing the data publicly available for the hundred unrelated subjects of the Human Connectome Project. Our results demonstrate that, depending on the level of details requested, a speedup of several orders of magnitudes can be obtained.
[ { "version": "v1", "created": "Thu, 27 Apr 2017 15:52:23 GMT" } ]
2017-04-28T00:00:00
[ [ "Honnorat", "Nicolas", "" ], [ "Davatzikos", "Christos", "" ] ]
TITLE: Sparse Hierachical Extrapolated Parametric Methods for Cortical Data Analysis ABSTRACT: Many neuroimaging studies focus on the cortex, in order to benefit from better signal to noise ratios and reduced computational burden. Cortical data are usually projected onto a reference mesh, where subsequent analyses are carried out. Several multiscale approaches have been proposed for analyzing these surface data, such as spherical harmonics and graph wavelets. As far as we know, however, the hierarchical structure of the template icosahedral meshes used by most neuroimaging software has never been exploited for cortical data factorization. In this paper, we demonstrate how the structure of the ubiquitous icosahedral meshes can be exploited by data factorization methods such as sparse dictionary learning, and we assess the optimization speed-up offered by extrapolation methods in this context. By testing different sparsity-inducing norms, extrapolation methods, and factorization schemes, we compare the performances of eleven methods for analyzing four datasets: two structural and two functional MRI datasets obtained by processing the data publicly available for the hundred unrelated subjects of the Human Connectome Project. Our results demonstrate that, depending on the level of details requested, a speedup of several orders of magnitudes can be obtained.
no_new_dataset
0.949576
1511.08769
Andrea Montanari
Adel Javanmard and Andrea Montanari and Federico Ricci-Tersenghi
Phase Transitions in Semidefinite Relaxations
71 pages, 24 pdf figures
Proceedings of the National Academy of Sciences 113, E2218-E2223 (2016)
10.1073/pnas.1523097113
null
cond-mat.stat-mech cs.DM cs.IT math.IT
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Statistical inference problems arising within signal processing, data mining, and machine learning naturally give rise to hard combinatorial optimization problems. These problems become intractable when the dimensionality of the data is large, as is often the case for modern datasets. A popular idea is to construct convex relaxations of these combinatorial problems, which can be solved efficiently for large scale datasets. Semidefinite programming (SDP) relaxations are among the most powerful methods in this family, and are surprisingly well-suited for a broad range of problems where data take the form of matrices or graphs. It has been observed several times that, when the `statistical noise' is small enough, SDP relaxations correctly detect the underlying combinatorial structures. In this paper we develop asymptotic predictions for several `detection thresholds,' as well as for the estimation error above these thresholds. We study some classical SDP relaxations for statistical problems motivated by graph synchronization and community detection in networks. We map these optimization problems to statistical mechanics models with vector spins, and use non-rigorous techniques from statistical mechanics to characterize the corresponding phase transitions. Our results clarify the effectiveness of SDP relaxations in solving high-dimensional statistical problems.
[ { "version": "v1", "created": "Fri, 27 Nov 2015 19:16:24 GMT" }, { "version": "v2", "created": "Mon, 4 Jan 2016 21:37:50 GMT" } ]
2017-04-27T00:00:00
[ [ "Javanmard", "Adel", "" ], [ "Montanari", "Andrea", "" ], [ "Ricci-Tersenghi", "Federico", "" ] ]
TITLE: Phase Transitions in Semidefinite Relaxations ABSTRACT: Statistical inference problems arising within signal processing, data mining, and machine learning naturally give rise to hard combinatorial optimization problems. These problems become intractable when the dimensionality of the data is large, as is often the case for modern datasets. A popular idea is to construct convex relaxations of these combinatorial problems, which can be solved efficiently for large scale datasets. Semidefinite programming (SDP) relaxations are among the most powerful methods in this family, and are surprisingly well-suited for a broad range of problems where data take the form of matrices or graphs. It has been observed several times that, when the `statistical noise' is small enough, SDP relaxations correctly detect the underlying combinatorial structures. In this paper we develop asymptotic predictions for several `detection thresholds,' as well as for the estimation error above these thresholds. We study some classical SDP relaxations for statistical problems motivated by graph synchronization and community detection in networks. We map these optimization problems to statistical mechanics models with vector spins, and use non-rigorous techniques from statistical mechanics to characterize the corresponding phase transitions. Our results clarify the effectiveness of SDP relaxations in solving high-dimensional statistical problems.
no_new_dataset
0.941547
1604.02388
Yang He
Yang He, Wei-Chen Chiu, Margret Keuper, Mario Fritz
STD2P: RGBD Semantic Segmentation Using Spatio-Temporal Data-Driven Pooling
To appear in CVPR 2017
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a novel superpixel-based multi-view convolutional neural network for semantic image segmentation. The proposed network produces a high quality segmentation of a single image by leveraging information from additional views of the same scene. Particularly in indoor videos such as captured by robotic platforms or handheld and bodyworn RGBD cameras, nearby video frames provide diverse viewpoints and additional context of objects and scenes. To leverage such information, we first compute region correspondences by optical flow and image boundary-based superpixels. Given these region correspondences, we propose a novel spatio-temporal pooling layer to aggregate information over space and time. We evaluate our approach on the NYU--Depth--V2 and the SUN3D datasets and compare it to various state-of-the-art single-view and multi-view approaches. Besides a general improvement over the state-of-the-art, we also show the benefits of making use of unlabeled frames during training for multi-view as well as single-view prediction.
[ { "version": "v1", "created": "Fri, 8 Apr 2016 16:01:34 GMT" }, { "version": "v2", "created": "Thu, 9 Jun 2016 19:52:02 GMT" }, { "version": "v3", "created": "Wed, 26 Apr 2017 13:13:02 GMT" } ]
2017-04-27T00:00:00
[ [ "He", "Yang", "" ], [ "Chiu", "Wei-Chen", "" ], [ "Keuper", "Margret", "" ], [ "Fritz", "Mario", "" ] ]
TITLE: STD2P: RGBD Semantic Segmentation Using Spatio-Temporal Data-Driven Pooling ABSTRACT: We propose a novel superpixel-based multi-view convolutional neural network for semantic image segmentation. The proposed network produces a high quality segmentation of a single image by leveraging information from additional views of the same scene. Particularly in indoor videos such as captured by robotic platforms or handheld and bodyworn RGBD cameras, nearby video frames provide diverse viewpoints and additional context of objects and scenes. To leverage such information, we first compute region correspondences by optical flow and image boundary-based superpixels. Given these region correspondences, we propose a novel spatio-temporal pooling layer to aggregate information over space and time. We evaluate our approach on the NYU--Depth--V2 and the SUN3D datasets and compare it to various state-of-the-art single-view and multi-view approaches. Besides a general improvement over the state-of-the-art, we also show the benefits of making use of unlabeled frames during training for multi-view as well as single-view prediction.
no_new_dataset
0.946843
1704.00514
Isabelle Augenstein
Isabelle Augenstein, Anders S{\o}gaard
Multi-Task Learning of Keyphrase Boundary Classification
ACL 2017
null
null
null
cs.CL cs.AI stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Keyphrase boundary classification (KBC) is the task of detecting keyphrases in scientific articles and labelling them with respect to predefined types. Although important in practice, this task is so far underexplored, partly due to the lack of labelled data. To overcome this, we explore several auxiliary tasks, including semantic super-sense tagging and identification of multi-word expressions, and cast the task as a multi-task learning problem with deep recurrent neural networks. Our multi-task models perform significantly better than previous state of the art approaches on two scientific KBC datasets, particularly for long keyphrases.
[ { "version": "v1", "created": "Mon, 3 Apr 2017 10:25:22 GMT" }, { "version": "v2", "created": "Wed, 26 Apr 2017 16:48:49 GMT" } ]
2017-04-27T00:00:00
[ [ "Augenstein", "Isabelle", "" ], [ "Søgaard", "Anders", "" ] ]
TITLE: Multi-Task Learning of Keyphrase Boundary Classification ABSTRACT: Keyphrase boundary classification (KBC) is the task of detecting keyphrases in scientific articles and labelling them with respect to predefined types. Although important in practice, this task is so far underexplored, partly due to the lack of labelled data. To overcome this, we explore several auxiliary tasks, including semantic super-sense tagging and identification of multi-word expressions, and cast the task as a multi-task learning problem with deep recurrent neural networks. Our multi-task models perform significantly better than previous state of the art approaches on two scientific KBC datasets, particularly for long keyphrases.
no_new_dataset
0.951051
1704.06485
Byeongchang Kim
Cesc Chunseong Park, Byeongchang Kim, Gunhee Kim
Attend to You: Personalized Image Captioning with Context Sequence Memory Networks
Accepted paper at CVPR 2017
null
null
null
cs.CV cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We address personalization issues of image captioning, which have not been discussed yet in previous research. For a query image, we aim to generate a descriptive sentence, accounting for prior knowledge such as the user's active vocabularies in previous documents. As applications of personalized image captioning, we tackle two post automation tasks: hashtag prediction and post generation, on our newly collected Instagram dataset, consisting of 1.1M posts from 6.3K users. We propose a novel captioning model named Context Sequence Memory Network (CSMN). Its unique updates over previous memory network models include (i) exploiting memory as a repository for multiple types of context information, (ii) appending previously generated words into memory to capture long-term information without suffering from the vanishing gradient problem, and (iii) adopting CNN memory structure to jointly represent nearby ordered memory slots for better context understanding. With quantitative evaluation and user studies via Amazon Mechanical Turk, we show the effectiveness of the three novel features of CSMN and its performance enhancement for personalized image captioning over state-of-the-art captioning models.
[ { "version": "v1", "created": "Fri, 21 Apr 2017 11:29:07 GMT" }, { "version": "v2", "created": "Tue, 25 Apr 2017 23:30:43 GMT" } ]
2017-04-27T00:00:00
[ [ "Park", "Cesc Chunseong", "" ], [ "Kim", "Byeongchang", "" ], [ "Kim", "Gunhee", "" ] ]
TITLE: Attend to You: Personalized Image Captioning with Context Sequence Memory Networks ABSTRACT: We address personalization issues of image captioning, which have not been discussed yet in previous research. For a query image, we aim to generate a descriptive sentence, accounting for prior knowledge such as the user's active vocabularies in previous documents. As applications of personalized image captioning, we tackle two post automation tasks: hashtag prediction and post generation, on our newly collected Instagram dataset, consisting of 1.1M posts from 6.3K users. We propose a novel captioning model named Context Sequence Memory Network (CSMN). Its unique updates over previous memory network models include (i) exploiting memory as a repository for multiple types of context information, (ii) appending previously generated words into memory to capture long-term information without suffering from the vanishing gradient problem, and (iii) adopting CNN memory structure to jointly represent nearby ordered memory slots for better context understanding. With quantitative evaluation and user studies via Amazon Mechanical Turk, we show the effectiveness of the three novel features of CSMN and its performance enhancement for personalized image captioning over state-of-the-art captioning models.
new_dataset
0.959459
1704.07938
Tien Thanh Nguyen
Tien Thanh Nguyen, Thi Thu Thuy Nguyen, Xuan Cuong Pham, Alan Wee-Chung Liew, James C. Bezdek
An ensemble-based online learning algorithm for streaming data
19 pages, 3 figures
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this study, we introduce an ensemble-based approach for online machine learning. The ensemble of base classifiers in our approach is obtained by learning Naive Bayes classifiers on different training sets which are generated by projecting the original training set to lower dimensional space. We propose a mechanism to learn sequences of data using data chunks paradigm. The experiments conducted on a number of UCI datasets and one synthetic dataset demonstrate that the proposed approach performs significantly better than some well-known online learning algorithms.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 00:33:36 GMT" } ]
2017-04-27T00:00:00
[ [ "Nguyen", "Tien Thanh", "" ], [ "Nguyen", "Thi Thu Thuy", "" ], [ "Pham", "Xuan Cuong", "" ], [ "Liew", "Alan Wee-Chung", "" ], [ "Bezdek", "James C.", "" ] ]
TITLE: An ensemble-based online learning algorithm for streaming data ABSTRACT: In this study, we introduce an ensemble-based approach for online machine learning. The ensemble of base classifiers in our approach is obtained by learning Naive Bayes classifiers on different training sets which are generated by projecting the original training set to lower dimensional space. We propose a mechanism to learn sequences of data using data chunks paradigm. The experiments conducted on a number of UCI datasets and one synthetic dataset demonstrate that the proposed approach performs significantly better than some well-known online learning algorithms.
no_new_dataset
0.94743
1704.07969
Tejal Bhamre
Tejal Bhamre, Teng Zhang, Amit Singer
Anisotropic twicing for single particle reconstruction using autocorrelation analysis
null
null
null
null
cs.CV q-bio.BM stat.AP stat.ME
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The missing phase problem in X-ray crystallography is commonly solved using the technique of molecular replacement, which borrows phases from a previously solved homologous structure, and appends them to the measured Fourier magnitudes of the diffraction patterns of the unknown structure. More recently, molecular replacement has been proposed for solving the missing orthogonal matrices problem arising in Kam's autocorrelation analysis for single particle reconstruction using X-ray free electron lasers and cryo-EM. In classical molecular replacement, it is common to estimate the magnitudes of the unknown structure as twice the measured magnitudes minus the magnitudes of the homologous structure, a procedure known as `twicing'. Mathematically, this is equivalent to finding an unbiased estimator for a complex-valued scalar. We generalize this scheme for the case of estimating real or complex valued matrices arising in single particle autocorrelation analysis. We name this approach "Anisotropic Twicing" because unlike the scalar case, the unbiased estimator is not obtained by a simple magnitude isotropic correction. We compare the performance of the least squares, twicing and anisotropic twicing estimators on synthetic and experimental datasets. We demonstrate 3D homology modeling in cryo-EM directly from experimental data without iterative refinement or class averaging, for the first time.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 04:47:01 GMT" } ]
2017-04-27T00:00:00
[ [ "Bhamre", "Tejal", "" ], [ "Zhang", "Teng", "" ], [ "Singer", "Amit", "" ] ]
TITLE: Anisotropic twicing for single particle reconstruction using autocorrelation analysis ABSTRACT: The missing phase problem in X-ray crystallography is commonly solved using the technique of molecular replacement, which borrows phases from a previously solved homologous structure, and appends them to the measured Fourier magnitudes of the diffraction patterns of the unknown structure. More recently, molecular replacement has been proposed for solving the missing orthogonal matrices problem arising in Kam's autocorrelation analysis for single particle reconstruction using X-ray free electron lasers and cryo-EM. In classical molecular replacement, it is common to estimate the magnitudes of the unknown structure as twice the measured magnitudes minus the magnitudes of the homologous structure, a procedure known as `twicing'. Mathematically, this is equivalent to finding an unbiased estimator for a complex-valued scalar. We generalize this scheme for the case of estimating real or complex valued matrices arising in single particle autocorrelation analysis. We name this approach "Anisotropic Twicing" because unlike the scalar case, the unbiased estimator is not obtained by a simple magnitude isotropic correction. We compare the performance of the least squares, twicing and anisotropic twicing estimators on synthetic and experimental datasets. We demonstrate 3D homology modeling in cryo-EM directly from experimental data without iterative refinement or class averaging, for the first time.
no_new_dataset
0.956145
1704.08088
Leandro Dos Santos
Leandro B. dos Santos, Edilson A. Corr\^ea Jr, Osvaldo N. Oliveira Jr, Diego R. Amancio, Let\'icia L. Mansur and Sandra M. Alu\'isio
Enriching Complex Networks with Word Embeddings for Detecting Mild Cognitive Impairment from Speech Transcripts
Published in Annual Meeting of the Association for Computational Linguist 2017
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Mild Cognitive Impairment (MCI) is a mental disorder difficult to diagnose. Linguistic features, mainly from parsers, have been used to detect MCI, but this is not suitable for large-scale assessments. MCI disfluencies produce non-grammatical speech that requires manual or high precision automatic correction of transcripts. In this paper, we modeled transcripts into complex networks and enriched them with word embedding (CNE) to better represent short texts produced in neuropsychological assessments. The network measurements were applied with well-known classifiers to automatically identify MCI in transcripts, in a binary classification task. A comparison was made with the performance of traditional approaches using Bag of Words (BoW) and linguistic features for three datasets: DementiaBank in English, and Cinderella and Arizona-Battery in Portuguese. Overall, CNE provided higher accuracy than using only complex networks, while Support Vector Machine was superior to other classifiers. CNE provided the highest accuracies for DementiaBank and Cinderella, but BoW was more efficient for the Arizona-Battery dataset probably owing to its short narratives. The approach using linguistic features yielded higher accuracy if the transcriptions of the Cinderella dataset were manually revised. Taken together, the results indicate that complex networks enriched with embedding is promising for detecting MCI in large-scale assessments
[ { "version": "v1", "created": "Wed, 26 Apr 2017 13:06:25 GMT" } ]
2017-04-27T00:00:00
[ [ "Santos", "Leandro B. dos", "" ], [ "Corrêa", "Edilson A.", "Jr" ], [ "Oliveira", "Osvaldo N.", "Jr" ], [ "Amancio", "Diego R.", "" ], [ "Mansur", "Letícia L.", "" ], [ "Aluísio", "Sandra M.", "" ] ]
TITLE: Enriching Complex Networks with Word Embeddings for Detecting Mild Cognitive Impairment from Speech Transcripts ABSTRACT: Mild Cognitive Impairment (MCI) is a mental disorder difficult to diagnose. Linguistic features, mainly from parsers, have been used to detect MCI, but this is not suitable for large-scale assessments. MCI disfluencies produce non-grammatical speech that requires manual or high precision automatic correction of transcripts. In this paper, we modeled transcripts into complex networks and enriched them with word embedding (CNE) to better represent short texts produced in neuropsychological assessments. The network measurements were applied with well-known classifiers to automatically identify MCI in transcripts, in a binary classification task. A comparison was made with the performance of traditional approaches using Bag of Words (BoW) and linguistic features for three datasets: DementiaBank in English, and Cinderella and Arizona-Battery in Portuguese. Overall, CNE provided higher accuracy than using only complex networks, while Support Vector Machine was superior to other classifiers. CNE provided the highest accuracies for DementiaBank and Cinderella, but BoW was more efficient for the Arizona-Battery dataset probably owing to its short narratives. The approach using linguistic features yielded higher accuracy if the transcriptions of the Cinderella dataset were manually revised. Taken together, the results indicate that complex networks enriched with embedding is promising for detecting MCI in large-scale assessments
no_new_dataset
0.952574
1704.08134
Mohammadreza Soltaninejad
Mohammadreza Soltaninejad, Lei Zhang, Tryphon Lambrou, Nigel Allinson, Xujiong Ye
Multimodal MRI brain tumor segmentation using random forests with features learned from fully convolutional neural network
null
null
null
null
cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we propose a novel learning based method for automated segmenta-tion of brain tumor in multimodal MRI images. The machine learned features from fully convolutional neural network (FCN) and hand-designed texton fea-tures are used to classify the MRI image voxels. The score map with pixel-wise predictions is used as a feature map which is learned from multimodal MRI train-ing dataset using the FCN. The learned features are then applied to random for-ests to classify each MRI image voxel into normal brain tissues and different parts of tumor. The method was evaluated on BRATS 2013 challenge dataset. The results show that the application of the random forest classifier to multimodal MRI images using machine-learned features based on FCN and hand-designed features based on textons provides promising segmentations. The Dice overlap measure for automatic brain tumor segmentation against ground truth is 0.88, 080 and 0.73 for complete tumor, core and enhancing tumor, respectively.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 14:22:02 GMT" } ]
2017-04-27T00:00:00
[ [ "Soltaninejad", "Mohammadreza", "" ], [ "Zhang", "Lei", "" ], [ "Lambrou", "Tryphon", "" ], [ "Allinson", "Nigel", "" ], [ "Ye", "Xujiong", "" ] ]
TITLE: Multimodal MRI brain tumor segmentation using random forests with features learned from fully convolutional neural network ABSTRACT: In this paper, we propose a novel learning based method for automated segmenta-tion of brain tumor in multimodal MRI images. The machine learned features from fully convolutional neural network (FCN) and hand-designed texton fea-tures are used to classify the MRI image voxels. The score map with pixel-wise predictions is used as a feature map which is learned from multimodal MRI train-ing dataset using the FCN. The learned features are then applied to random for-ests to classify each MRI image voxel into normal brain tissues and different parts of tumor. The method was evaluated on BRATS 2013 challenge dataset. The results show that the application of the random forest classifier to multimodal MRI images using machine-learned features based on FCN and hand-designed features based on textons provides promising segmentations. The Dice overlap measure for automatic brain tumor segmentation against ground truth is 0.88, 080 and 0.73 for complete tumor, core and enhancing tumor, respectively.
no_new_dataset
0.954605
1704.08243
Aishwarya Agrawal
Aishwarya Agrawal, Aniruddha Kembhavi, Dhruv Batra, Devi Parikh
C-VQA: A Compositional Split of the Visual Question Answering (VQA) v1.0 Dataset
null
null
null
null
cs.CV cs.AI cs.CL cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Visual Question Answering (VQA) has received a lot of attention over the past couple of years. A number of deep learning models have been proposed for this task. However, it has been shown that these models are heavily driven by superficial correlations in the training data and lack compositionality -- the ability to answer questions about unseen compositions of seen concepts. This compositionality is desirable and central to intelligence. In this paper, we propose a new setting for Visual Question Answering where the test question-answer pairs are compositionally novel compared to training question-answer pairs. To facilitate developing models under this setting, we present a new compositional split of the VQA v1.0 dataset, which we call Compositional VQA (C-VQA). We analyze the distribution of questions and answers in the C-VQA splits. Finally, we evaluate several existing VQA models under this new setting and show that the performances of these models degrade by a significant amount compared to the original VQA setting.
[ { "version": "v1", "created": "Wed, 26 Apr 2017 17:57:59 GMT" } ]
2017-04-27T00:00:00
[ [ "Agrawal", "Aishwarya", "" ], [ "Kembhavi", "Aniruddha", "" ], [ "Batra", "Dhruv", "" ], [ "Parikh", "Devi", "" ] ]
TITLE: C-VQA: A Compositional Split of the Visual Question Answering (VQA) v1.0 Dataset ABSTRACT: Visual Question Answering (VQA) has received a lot of attention over the past couple of years. A number of deep learning models have been proposed for this task. However, it has been shown that these models are heavily driven by superficial correlations in the training data and lack compositionality -- the ability to answer questions about unseen compositions of seen concepts. This compositionality is desirable and central to intelligence. In this paper, we propose a new setting for Visual Question Answering where the test question-answer pairs are compositionally novel compared to training question-answer pairs. To facilitate developing models under this setting, we present a new compositional split of the VQA v1.0 dataset, which we call Compositional VQA (C-VQA). We analyze the distribution of questions and answers in the C-VQA splits. Finally, we evaluate several existing VQA models under this new setting and show that the performances of these models degrade by a significant amount compared to the original VQA setting.
new_dataset
0.936749
1409.5185
Zhuowen Tu
Chen-Yu Lee, Saining Xie, Patrick Gallagher, Zhengyou Zhang, Zhuowen Tu
Deeply-Supervised Nets
Patent disclosure, UCSD Docket No. SD2014-313, filed on May 22, 2014
null
null
null
stat.ML cs.CV cs.LG cs.NE
http://creativecommons.org/licenses/by-nc-sa/3.0/
Our proposed deeply-supervised nets (DSN) method simultaneously minimizes classification error while making the learning process of hidden layers direct and transparent. We make an attempt to boost the classification performance by studying a new formulation in deep networks. Three aspects in convolutional neural networks (CNN) style architectures are being looked at: (1) transparency of the intermediate layers to the overall classification; (2) discriminativeness and robustness of learned features, especially in the early layers; (3) effectiveness in training due to the presence of the exploding and vanishing gradients. We introduce "companion objective" to the individual hidden layers, in addition to the overall objective at the output layer (a different strategy to layer-wise pre-training). We extend techniques from stochastic gradient methods to analyze our algorithm. The advantage of our method is evident and our experimental result on benchmark datasets shows significant performance gain over existing methods (e.g. all state-of-the-art results on MNIST, CIFAR-10, CIFAR-100, and SVHN).
[ { "version": "v1", "created": "Thu, 18 Sep 2014 04:08:25 GMT" }, { "version": "v2", "created": "Thu, 25 Sep 2014 05:03:06 GMT" } ]
2017-04-26T00:00:00
[ [ "Lee", "Chen-Yu", "" ], [ "Xie", "Saining", "" ], [ "Gallagher", "Patrick", "" ], [ "Zhang", "Zhengyou", "" ], [ "Tu", "Zhuowen", "" ] ]
TITLE: Deeply-Supervised Nets ABSTRACT: Our proposed deeply-supervised nets (DSN) method simultaneously minimizes classification error while making the learning process of hidden layers direct and transparent. We make an attempt to boost the classification performance by studying a new formulation in deep networks. Three aspects in convolutional neural networks (CNN) style architectures are being looked at: (1) transparency of the intermediate layers to the overall classification; (2) discriminativeness and robustness of learned features, especially in the early layers; (3) effectiveness in training due to the presence of the exploding and vanishing gradients. We introduce "companion objective" to the individual hidden layers, in addition to the overall objective at the output layer (a different strategy to layer-wise pre-training). We extend techniques from stochastic gradient methods to analyze our algorithm. The advantage of our method is evident and our experimental result on benchmark datasets shows significant performance gain over existing methods (e.g. all state-of-the-art results on MNIST, CIFAR-10, CIFAR-100, and SVHN).
no_new_dataset
0.946892
1604.07236
Arkaitz Zubiaga
Arkaitz Zubiaga, Alex Voss, Rob Procter, Maria Liakata, Bo Wang, Adam Tsakalidis
Towards Real-Time, Country-Level Location Classification of Worldwide Tweets
Accepted for publication in IEEE Transactions on Knowledge and Data Engineering (IEEE TKDE)
null
null
null
cs.IR cs.CL cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In contrast to much previous work that has focused on location classification of tweets restricted to a specific country, here we undertake the task in a broader context by classifying global tweets at the country level, which is so far unexplored in a real-time scenario. We analyse the extent to which a tweet's country of origin can be determined by making use of eight tweet-inherent features for classification. Furthermore, we use two datasets, collected a year apart from each other, to analyse the extent to which a model trained from historical tweets can still be leveraged for classification of new tweets. With classification experiments on all 217 countries in our datasets, as well as on the top 25 countries, we offer some insights into the best use of tweet-inherent features for an accurate country-level classification of tweets. We find that the use of a single feature, such as the use of tweet content alone -- the most widely used feature in previous work -- leaves much to be desired. Choosing an appropriate combination of both tweet content and metadata can actually lead to substantial improvements of between 20\% and 50\%. We observe that tweet content, the user's self-reported location and the user's real name, all of which are inherent in a tweet and available in a real-time scenario, are particularly useful to determine the country of origin. We also experiment on the applicability of a model trained on historical tweets to classify new tweets, finding that the choice of a particular combination of features whose utility does not fade over time can actually lead to comparable performance, avoiding the need to retrain. However, the difficulty of achieving accurate classification increases slightly for countries with multiple commonalities, especially for English and Spanish speaking countries.
[ { "version": "v1", "created": "Mon, 25 Apr 2016 12:50:50 GMT" }, { "version": "v2", "created": "Thu, 1 Dec 2016 18:35:36 GMT" }, { "version": "v3", "created": "Tue, 25 Apr 2017 11:03:05 GMT" } ]
2017-04-26T00:00:00
[ [ "Zubiaga", "Arkaitz", "" ], [ "Voss", "Alex", "" ], [ "Procter", "Rob", "" ], [ "Liakata", "Maria", "" ], [ "Wang", "Bo", "" ], [ "Tsakalidis", "Adam", "" ] ]
TITLE: Towards Real-Time, Country-Level Location Classification of Worldwide Tweets ABSTRACT: In contrast to much previous work that has focused on location classification of tweets restricted to a specific country, here we undertake the task in a broader context by classifying global tweets at the country level, which is so far unexplored in a real-time scenario. We analyse the extent to which a tweet's country of origin can be determined by making use of eight tweet-inherent features for classification. Furthermore, we use two datasets, collected a year apart from each other, to analyse the extent to which a model trained from historical tweets can still be leveraged for classification of new tweets. With classification experiments on all 217 countries in our datasets, as well as on the top 25 countries, we offer some insights into the best use of tweet-inherent features for an accurate country-level classification of tweets. We find that the use of a single feature, such as the use of tweet content alone -- the most widely used feature in previous work -- leaves much to be desired. Choosing an appropriate combination of both tweet content and metadata can actually lead to substantial improvements of between 20\% and 50\%. We observe that tweet content, the user's self-reported location and the user's real name, all of which are inherent in a tweet and available in a real-time scenario, are particularly useful to determine the country of origin. We also experiment on the applicability of a model trained on historical tweets to classify new tweets, finding that the choice of a particular combination of features whose utility does not fade over time can actually lead to comparable performance, avoiding the need to retrain. However, the difficulty of achieving accurate classification increases slightly for countries with multiple commonalities, especially for English and Spanish speaking countries.
no_new_dataset
0.936692
1606.00368
Ryan Levy
Ryan Levy, J.P.F. LeBlanc, Emanuel Gull
Implementation of the Maximum Entropy Method for Analytic Continuation
Code can be found at https://github.com/CQMP/Maxent
null
10.1016/j.cpc.2017.01.018
null
physics.comp-ph cond-mat.str-el
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present $\texttt{Maxent}$, a tool for performing analytic continuation of spectral functions using the maximum entropy method. The code operates on discrete imaginary axis datasets (values with uncertainties) and transforms this input to the real axis. The code works for imaginary time and Matsubara frequency data and implements the 'Legendre' representation of finite temperature Green's functions. It implements a variety of kernels, default models, and grids for continuing bosonic, fermionic, anomalous, and other data. Our implementation is licensed under GPLv2 and extensively documented. This paper shows the use of the programs in detail.
[ { "version": "v1", "created": "Wed, 1 Jun 2016 17:47:56 GMT" } ]
2017-04-26T00:00:00
[ [ "Levy", "Ryan", "" ], [ "LeBlanc", "J. P. F.", "" ], [ "Gull", "Emanuel", "" ] ]
TITLE: Implementation of the Maximum Entropy Method for Analytic Continuation ABSTRACT: We present $\texttt{Maxent}$, a tool for performing analytic continuation of spectral functions using the maximum entropy method. The code operates on discrete imaginary axis datasets (values with uncertainties) and transforms this input to the real axis. The code works for imaginary time and Matsubara frequency data and implements the 'Legendre' representation of finite temperature Green's functions. It implements a variety of kernels, default models, and grids for continuing bosonic, fermionic, anomalous, and other data. Our implementation is licensed under GPLv2 and extensively documented. This paper shows the use of the programs in detail.
no_new_dataset
0.949295
1607.03333
Liangqiong Qu
Liangqiong Qu, Shengfeng He, Jiawei Zhang, Jiandong Tian, Yandong Tang, and Qingxiong Yang
RGBD Salient Object Detection via Deep Fusion
This paper has been submitted to IEEE Transactions on Image Processing
null
10.1109/TIP.2017.2682981
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Numerous efforts have been made to design different low level saliency cues for the RGBD saliency detection, such as color or depth contrast features, background and color compactness priors. However, how these saliency cues interact with each other and how to incorporate these low level saliency cues effectively to generate a master saliency map remain a challenging problem. In this paper, we design a new convolutional neural network (CNN) to fuse different low level saliency cues into hierarchical features for automatically detecting salient objects in RGBD images. In contrast to the existing works that directly feed raw image pixels to the CNN, the proposed method takes advantage of the knowledge in traditional saliency detection by adopting various meaningful and well-designed saliency feature vectors as input. This can guide the training of CNN towards detecting salient object more effectively due to the reduced learning ambiguity. We then integrate a Laplacian propagation framework with the learned CNN to extract a spatially consistent saliency map by exploiting the intrinsic structure of the input image. Extensive quantitative and qualitative experimental evaluations on three datasets demonstrate that the proposed method consistently outperforms state-of-the-art methods.
[ { "version": "v1", "created": "Tue, 12 Jul 2016 12:32:56 GMT" } ]
2017-04-26T00:00:00
[ [ "Qu", "Liangqiong", "" ], [ "He", "Shengfeng", "" ], [ "Zhang", "Jiawei", "" ], [ "Tian", "Jiandong", "" ], [ "Tang", "Yandong", "" ], [ "Yang", "Qingxiong", "" ] ]
TITLE: RGBD Salient Object Detection via Deep Fusion ABSTRACT: Numerous efforts have been made to design different low level saliency cues for the RGBD saliency detection, such as color or depth contrast features, background and color compactness priors. However, how these saliency cues interact with each other and how to incorporate these low level saliency cues effectively to generate a master saliency map remain a challenging problem. In this paper, we design a new convolutional neural network (CNN) to fuse different low level saliency cues into hierarchical features for automatically detecting salient objects in RGBD images. In contrast to the existing works that directly feed raw image pixels to the CNN, the proposed method takes advantage of the knowledge in traditional saliency detection by adopting various meaningful and well-designed saliency feature vectors as input. This can guide the training of CNN towards detecting salient object more effectively due to the reduced learning ambiguity. We then integrate a Laplacian propagation framework with the learned CNN to extract a spatially consistent saliency map by exploiting the intrinsic structure of the input image. Extensive quantitative and qualitative experimental evaluations on three datasets demonstrate that the proposed method consistently outperforms state-of-the-art methods.
no_new_dataset
0.95018
1610.01119
Limin Wang
Limin Wang, Sheng Guo, Weilin Huang, Yuanjun Xiong, Yu Qiao
Knowledge Guided Disambiguation for Large-Scale Scene Classification with Multi-Resolution CNNs
To appear in IEEE Transactions on Image Processing. Code and models are available at https://github.com/wanglimin/MRCNN-Scene-Recognition
null
10.1109/TIP.2017.2675339
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Convolutional Neural Networks (CNNs) have made remarkable progress on scene recognition, partially due to these recent large-scale scene datasets, such as the Places and Places2. Scene categories are often defined by multi-level information, including local objects, global layout, and background environment, thus leading to large intra-class variations. In addition, with the increasing number of scene categories, label ambiguity has become another crucial issue in large-scale classification. This paper focuses on large-scale scene recognition and makes two major contributions to tackle these issues. First, we propose a multi-resolution CNN architecture that captures visual content and structure at multiple levels. The multi-resolution CNNs are composed of coarse resolution CNNs and fine resolution CNNs, which are complementary to each other. Second, we design two knowledge guided disambiguation techniques to deal with the problem of label ambiguity. (i) We exploit the knowledge from the confusion matrix computed on validation data to merge ambiguous classes into a super category. (ii) We utilize the knowledge of extra networks to produce a soft label for each image. Then the super categories or soft labels are employed to guide CNN training on the Places2. We conduct extensive experiments on three large-scale image datasets (ImageNet, Places, and Places2), demonstrating the effectiveness of our approach. Furthermore, our method takes part in two major scene recognition challenges, and achieves the second place at the Places2 challenge in ILSVRC 2015, and the first place at the LSUN challenge in CVPR 2016. Finally, we directly test the learned representations on other scene benchmarks, and obtain the new state-of-the-art results on the MIT Indoor67 (86.7\%) and SUN397 (72.0\%). We release the code and models at~\url{https://github.com/wanglimin/MRCNN-Scene-Recognition}.
[ { "version": "v1", "created": "Tue, 4 Oct 2016 18:33:32 GMT" }, { "version": "v2", "created": "Tue, 21 Feb 2017 21:00:55 GMT" } ]
2017-04-26T00:00:00
[ [ "Wang", "Limin", "" ], [ "Guo", "Sheng", "" ], [ "Huang", "Weilin", "" ], [ "Xiong", "Yuanjun", "" ], [ "Qiao", "Yu", "" ] ]
TITLE: Knowledge Guided Disambiguation for Large-Scale Scene Classification with Multi-Resolution CNNs ABSTRACT: Convolutional Neural Networks (CNNs) have made remarkable progress on scene recognition, partially due to these recent large-scale scene datasets, such as the Places and Places2. Scene categories are often defined by multi-level information, including local objects, global layout, and background environment, thus leading to large intra-class variations. In addition, with the increasing number of scene categories, label ambiguity has become another crucial issue in large-scale classification. This paper focuses on large-scale scene recognition and makes two major contributions to tackle these issues. First, we propose a multi-resolution CNN architecture that captures visual content and structure at multiple levels. The multi-resolution CNNs are composed of coarse resolution CNNs and fine resolution CNNs, which are complementary to each other. Second, we design two knowledge guided disambiguation techniques to deal with the problem of label ambiguity. (i) We exploit the knowledge from the confusion matrix computed on validation data to merge ambiguous classes into a super category. (ii) We utilize the knowledge of extra networks to produce a soft label for each image. Then the super categories or soft labels are employed to guide CNN training on the Places2. We conduct extensive experiments on three large-scale image datasets (ImageNet, Places, and Places2), demonstrating the effectiveness of our approach. Furthermore, our method takes part in two major scene recognition challenges, and achieves the second place at the Places2 challenge in ILSVRC 2015, and the first place at the LSUN challenge in CVPR 2016. Finally, we directly test the learned representations on other scene benchmarks, and obtain the new state-of-the-art results on the MIT Indoor67 (86.7\%) and SUN397 (72.0\%). We release the code and models at~\url{https://github.com/wanglimin/MRCNN-Scene-Recognition}.
no_new_dataset
0.958731
1611.02730
Angelica I. Aviles
Angelica I. Aviles, Thomas Widlak, Alicia Casals, Maartje M. Nillesen and Habib Ammari
Robust Cardiac Motion Estimation using Ultrafast Ultrasound Data: A Low-Rank-Topology-Preserving Approach
15 pages, 10 figures, Physics in Medicine and Biology, 2017
null
10.1088/1361-6560/aa6914
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cardiac motion estimation is an important diagnostic tool to detect heart diseases and it has been explored with modalities such as MRI and conventional ultrasound (US) sequences. US cardiac motion estimation still presents challenges because of the complex motion patterns and the presence of noise. In this work, we propose a novel approach to estimate the cardiac motion using ultrafast ultrasound data. -- Our solution is based on a variational formulation characterized by the L2-regularized class. The displacement is represented by a lattice of b-splines and we ensure robustness by applying a maximum likelihood type estimator. While this is an important part of our solution, the main highlight of this paper is to combine a low-rank data representation with topology preservation. Low-rank data representation (achieved by finding the k-dominant singular values of a Casorati Matrix arranged from the data sequence) speeds up the global solution and achieves noise reduction. On the other hand, topology preservation (achieved by monitoring the Jacobian determinant) allows to radically rule out distortions while carefully controlling the size of allowed expansions and contractions. Our variational approach is carried out on a realistic dataset as well as on a simulated one. We demonstrate how our proposed variational solution deals with complex deformations through careful numerical experiments. While maintaining the accuracy of the solution, the low-rank preprocessing is shown to speed up the convergence of the variational problem. Beyond cardiac motion estimation, our approach is promising for the analysis of other organs that experience motion.
[ { "version": "v1", "created": "Wed, 26 Oct 2016 22:38:48 GMT" }, { "version": "v2", "created": "Tue, 25 Apr 2017 13:24:48 GMT" } ]
2017-04-26T00:00:00
[ [ "Aviles", "Angelica I.", "" ], [ "Widlak", "Thomas", "" ], [ "Casals", "Alicia", "" ], [ "Nillesen", "Maartje M.", "" ], [ "Ammari", "Habib", "" ] ]
TITLE: Robust Cardiac Motion Estimation using Ultrafast Ultrasound Data: A Low-Rank-Topology-Preserving Approach ABSTRACT: Cardiac motion estimation is an important diagnostic tool to detect heart diseases and it has been explored with modalities such as MRI and conventional ultrasound (US) sequences. US cardiac motion estimation still presents challenges because of the complex motion patterns and the presence of noise. In this work, we propose a novel approach to estimate the cardiac motion using ultrafast ultrasound data. -- Our solution is based on a variational formulation characterized by the L2-regularized class. The displacement is represented by a lattice of b-splines and we ensure robustness by applying a maximum likelihood type estimator. While this is an important part of our solution, the main highlight of this paper is to combine a low-rank data representation with topology preservation. Low-rank data representation (achieved by finding the k-dominant singular values of a Casorati Matrix arranged from the data sequence) speeds up the global solution and achieves noise reduction. On the other hand, topology preservation (achieved by monitoring the Jacobian determinant) allows to radically rule out distortions while carefully controlling the size of allowed expansions and contractions. Our variational approach is carried out on a realistic dataset as well as on a simulated one. We demonstrate how our proposed variational solution deals with complex deformations through careful numerical experiments. While maintaining the accuracy of the solution, the low-rank preprocessing is shown to speed up the convergence of the variational problem. Beyond cardiac motion estimation, our approach is promising for the analysis of other organs that experience motion.
no_new_dataset
0.949856
1612.04054
Zeng Zhi
Qingdong Hu, Hao Ma, Zhi Zeng, Jianping Cheng, Yunhua Chen, Shenming He, Junli Li, Manbin Shen, Shiyong Wu, Qian Yue, Jianfeng Yue, Hui Zhang
Neutron background measurements at China Jinping underground laboratory with a Bonner Multi-sphere Spectrometer
10 pages,6 Figures, 3 Tables
null
10.1016/j.nima.2017.03.048
null
physics.ins-det hep-ex nucl-ex
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The neutron background spectrum from thermal neutron to 20 MeV fast neutron was measured at the first experimental hall of China Jinping underground laboratory with a Bonner multi-sphere spectrometer. The measurement system was validated by a Cf252 source and inconformity was corrected. Due to micro charge discharge, the dataset was screened and background from the steel of the detectors was estimated by MC simulation. Based on genetic algorithm we obtained the energy distribution of the neutron and the total flux of neutron was (2.69 +/-1.02) *10^-5 cm^-2s^-1
[ { "version": "v1", "created": "Tue, 13 Dec 2016 08:09:42 GMT" } ]
2017-04-26T00:00:00
[ [ "Hu", "Qingdong", "" ], [ "Ma", "Hao", "" ], [ "Zeng", "Zhi", "" ], [ "Cheng", "Jianping", "" ], [ "Chen", "Yunhua", "" ], [ "He", "Shenming", "" ], [ "Li", "Junli", "" ], [ "Shen", "Manbin", "" ], [ "Wu", "Shiyong", "" ], [ "Yue", "Qian", "" ], [ "Yue", "Jianfeng", "" ], [ "Zhang", "Hui", "" ] ]
TITLE: Neutron background measurements at China Jinping underground laboratory with a Bonner Multi-sphere Spectrometer ABSTRACT: The neutron background spectrum from thermal neutron to 20 MeV fast neutron was measured at the first experimental hall of China Jinping underground laboratory with a Bonner multi-sphere spectrometer. The measurement system was validated by a Cf252 source and inconformity was corrected. Due to micro charge discharge, the dataset was screened and background from the steel of the detectors was estimated by MC simulation. Based on genetic algorithm we obtained the energy distribution of the neutron and the total flux of neutron was (2.69 +/-1.02) *10^-5 cm^-2s^-1
no_new_dataset
0.925769
1703.05871
Thomas Hartlep
Thomas Hartlep and Jeffrey N. Cuzzi and Brian Weston
Scale Dependence of Multiplier Distributions for Particle Concentration, Enstrophy and Dissipation in the Inertial Range of Homogeneous Turbulence
21 pages, 14 figures, accepted for publication in Physical Review E
null
10.1103/PhysRevE.95.033115
null
physics.flu-dyn
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Turbulent flows preferentially concentrate inertial particles depending on their stopping time or Stokes number, which can lead to significant spatial variations in the particle concentration. Cascade models are one way to describe this process in statistical terms. Here, we use a direct numerical simulation (DNS) dataset of homogeneous, isotropic turbulence to determine probability distribution functions (PDFs) for cascade multipliers, which determine the ratio by which a property is partitioned into sub-volumes as an eddy is envisioned to decay into smaller eddies. We present a technique for correcting effects of small particle numbers in the statistics. We determine multiplier PDFs for particle number, flow dissipation, and enstrophy, all of which are shown to be scale dependent. However, the particle multiplier PDFs collapse when scaled with an appropriately defined local Stokes number. As anticipated from earlier works, dissipation and enstrophy multiplier PDFs reach an asymptote for sufficiently small spatial scales. From the DNS measurements, we derive a cascade model that is used it to make predictions for the radial distribution function (RDF) for arbitrarily high Reynolds numbers, $Re$, finding good agreement with the asymptotic, infinite $Re$ inertial range theory of Zaichik and Alipchenkov [New Journal of Physics 11, 103018 (2009)]. We discuss implications of these results for the statistical modeling of the turbulent clustering process in the inertial range for high Reynolds numbers inaccessible to numerical simulations.
[ { "version": "v1", "created": "Fri, 17 Mar 2017 02:48:24 GMT" } ]
2017-04-26T00:00:00
[ [ "Hartlep", "Thomas", "" ], [ "Cuzzi", "Jeffrey N.", "" ], [ "Weston", "Brian", "" ] ]
TITLE: Scale Dependence of Multiplier Distributions for Particle Concentration, Enstrophy and Dissipation in the Inertial Range of Homogeneous Turbulence ABSTRACT: Turbulent flows preferentially concentrate inertial particles depending on their stopping time or Stokes number, which can lead to significant spatial variations in the particle concentration. Cascade models are one way to describe this process in statistical terms. Here, we use a direct numerical simulation (DNS) dataset of homogeneous, isotropic turbulence to determine probability distribution functions (PDFs) for cascade multipliers, which determine the ratio by which a property is partitioned into sub-volumes as an eddy is envisioned to decay into smaller eddies. We present a technique for correcting effects of small particle numbers in the statistics. We determine multiplier PDFs for particle number, flow dissipation, and enstrophy, all of which are shown to be scale dependent. However, the particle multiplier PDFs collapse when scaled with an appropriately defined local Stokes number. As anticipated from earlier works, dissipation and enstrophy multiplier PDFs reach an asymptote for sufficiently small spatial scales. From the DNS measurements, we derive a cascade model that is used it to make predictions for the radial distribution function (RDF) for arbitrarily high Reynolds numbers, $Re$, finding good agreement with the asymptotic, infinite $Re$ inertial range theory of Zaichik and Alipchenkov [New Journal of Physics 11, 103018 (2009)]. We discuss implications of these results for the statistical modeling of the turbulent clustering process in the inertial range for high Reynolds numbers inaccessible to numerical simulations.
no_new_dataset
0.95561
1703.08383
Joseph Lemley
Joseph Lemley, Shabab Bazrafkan, Peter Corcoran
Smart Augmentation - Learning an Optimal Data Augmentation Strategy
null
null
10.1109/ACCESS.2017.2696121
null
cs.AI cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A recurring problem faced when training neural networks is that there is typically not enough data to maximize the generalization capability of deep neural networks(DNN). There are many techniques to address this, including data augmentation, dropout, and transfer learning. In this paper, we introduce an additional method which we call Smart Augmentation and we show how to use it to increase the accuracy and reduce overfitting on a target network. Smart Augmentation works by creating a network that learns how to generate augmented data during the training process of a target network in a way that reduces that networks loss. This allows us to learn augmentations that minimize the error of that network. Smart Augmentation has shown the potential to increase accuracy by demonstrably significant measures on all datasets tested. In addition, it has shown potential to achieve similar or improved performance levels with significantly smaller network sizes in a number of tested cases.
[ { "version": "v1", "created": "Fri, 24 Mar 2017 12:07:34 GMT" } ]
2017-04-26T00:00:00
[ [ "Lemley", "Joseph", "" ], [ "Bazrafkan", "Shabab", "" ], [ "Corcoran", "Peter", "" ] ]
TITLE: Smart Augmentation - Learning an Optimal Data Augmentation Strategy ABSTRACT: A recurring problem faced when training neural networks is that there is typically not enough data to maximize the generalization capability of deep neural networks(DNN). There are many techniques to address this, including data augmentation, dropout, and transfer learning. In this paper, we introduce an additional method which we call Smart Augmentation and we show how to use it to increase the accuracy and reduce overfitting on a target network. Smart Augmentation works by creating a network that learns how to generate augmented data during the training process of a target network in a way that reduces that networks loss. This allows us to learn augmentations that minimize the error of that network. Smart Augmentation has shown the potential to increase accuracy by demonstrably significant measures on all datasets tested. In addition, it has shown potential to achieve similar or improved performance levels with significantly smaller network sizes in a number of tested cases.
no_new_dataset
0.949106
1704.06693
Sandipan Banerjee
Sandipan Banerjee, John S. Bernhard, Walter J. Scheirer, Kevin W. Bowyer, Patrick J. Flynn
SREFI: Synthesis of Realistic Example Face Images
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we propose a novel face synthesis approach that can generate an arbitrarily large number of synthetic images of both real and synthetic identities. Thus a face image dataset can be expanded in terms of the number of identities represented and the number of images per identity using this approach, without the identity-labeling and privacy complications that come from downloading images from the web. To measure the visual fidelity and uniqueness of the synthetic face images and identities, we conducted face matching experiments with both human participants and a CNN pre-trained on a dataset of 2.6M real face images. To evaluate the stability of these synthetic faces, we trained a CNN model with an augmented dataset containing close to 200,000 synthetic faces. We used a snapshot of this trained CNN to recognize extremely challenging frontal (real) face images. Experiments showed training with the augmented faces boosted the face recognition performance of the CNN.
[ { "version": "v1", "created": "Fri, 21 Apr 2017 19:59:47 GMT" }, { "version": "v2", "created": "Tue, 25 Apr 2017 03:54:34 GMT" } ]
2017-04-26T00:00:00
[ [ "Banerjee", "Sandipan", "" ], [ "Bernhard", "John S.", "" ], [ "Scheirer", "Walter J.", "" ], [ "Bowyer", "Kevin W.", "" ], [ "Flynn", "Patrick J.", "" ] ]
TITLE: SREFI: Synthesis of Realistic Example Face Images ABSTRACT: In this paper, we propose a novel face synthesis approach that can generate an arbitrarily large number of synthetic images of both real and synthetic identities. Thus a face image dataset can be expanded in terms of the number of identities represented and the number of images per identity using this approach, without the identity-labeling and privacy complications that come from downloading images from the web. To measure the visual fidelity and uniqueness of the synthetic face images and identities, we conducted face matching experiments with both human participants and a CNN pre-trained on a dataset of 2.6M real face images. To evaluate the stability of these synthetic faces, we trained a CNN model with an augmented dataset containing close to 200,000 synthetic faces. We used a snapshot of this trained CNN to recognize extremely challenging frontal (real) face images. Experiments showed training with the augmented faces boosted the face recognition performance of the CNN.
no_new_dataset
0.910147
1704.07160
Congqi Cao
Congqi Cao, Yifan Zhang, Chunjie Zhang and Hanqing Lu
Body Joint guided 3D Deep Convolutional Descriptors for Action Recognition
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Three dimensional convolutional neural networks (3D CNNs) have been established as a powerful tool to simultaneously learn features from both spatial and temporal dimensions, which is suitable to be applied to video-based action recognition. In this work, we propose not to directly use the activations of fully-connected layers of a 3D CNN as the video feature, but to use selective convolutional layer activations to form a discriminative descriptor for video. It pools the feature on the convolutional layers under the guidance of body joint positions. Two schemes of mapping body joints into convolutional feature maps for pooling are discussed. The body joint positions can be obtained from any off-the-shelf skeleton estimation algorithm. The helpfulness of the body joint guided feature pooling with inaccurate skeleton estimation is systematically evaluated. To make it end-to-end and do not rely on any sophisticated body joint detection algorithm, we further propose a two-stream bilinear model which can learn the guidance from the body joints and capture the spatio-temporal features simultaneously. In this model, the body joint guided feature pooling is conveniently formulated as a bilinear product operation. Experimental results on three real-world datasets demonstrate the effectiveness of body joint guided pooling which achieves promising performance.
[ { "version": "v1", "created": "Mon, 24 Apr 2017 11:58:24 GMT" }, { "version": "v2", "created": "Tue, 25 Apr 2017 15:08:05 GMT" } ]
2017-04-26T00:00:00
[ [ "Cao", "Congqi", "" ], [ "Zhang", "Yifan", "" ], [ "Zhang", "Chunjie", "" ], [ "Lu", "Hanqing", "" ] ]
TITLE: Body Joint guided 3D Deep Convolutional Descriptors for Action Recognition ABSTRACT: Three dimensional convolutional neural networks (3D CNNs) have been established as a powerful tool to simultaneously learn features from both spatial and temporal dimensions, which is suitable to be applied to video-based action recognition. In this work, we propose not to directly use the activations of fully-connected layers of a 3D CNN as the video feature, but to use selective convolutional layer activations to form a discriminative descriptor for video. It pools the feature on the convolutional layers under the guidance of body joint positions. Two schemes of mapping body joints into convolutional feature maps for pooling are discussed. The body joint positions can be obtained from any off-the-shelf skeleton estimation algorithm. The helpfulness of the body joint guided feature pooling with inaccurate skeleton estimation is systematically evaluated. To make it end-to-end and do not rely on any sophisticated body joint detection algorithm, we further propose a two-stream bilinear model which can learn the guidance from the body joints and capture the spatio-temporal features simultaneously. In this model, the body joint guided feature pooling is conveniently formulated as a bilinear product operation. Experimental results on three real-world datasets demonstrate the effectiveness of body joint guided pooling which achieves promising performance.
no_new_dataset
0.951097
1704.07405
Sabbir Ahmad
Sabbir Ahmad, Rafi Kamal, Mohammed Eunus Ali, Jianzhong Qi, Peter Scheuermann and Egemen Tanin
The Flexible Group Spatial Keyword Query
12 pages
null
null
null
cs.SI cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a new class of service for location based social networks, called the Flexible Group Spatial Keyword Query, which enables a group of users to collectively find a point of interest (POI) that optimizes an aggregate cost function combining both spatial distances and keyword similarities. In addition, our query service allows users to consider the tradeoffs between obtaining a sub-optimal solution for the entire group and obtaining an optimimized solution but only for a subgroup. We propose algorithms to process three variants of the query: (i) the group nearest neighbor with keywords query, which finds a POI that optimizes the aggregate cost function for the whole group of size n, (ii) the subgroup nearest neighbor with keywords query, which finds the optimal subgroup and a POI that optimizes the aggregate cost function for a given subgroup size m (m <= n), and (iii) the multiple subgroup nearest neighbor with keywords query, which finds optimal subgroups and corresponding POIs for each of the subgroup sizes in the range [m, n]. We design query processing algorithms based on branch-and-bound and best-first paradigms. Finally, we provide theoretical bounds and conduct extensive experiments with two real datasets which verify the effectiveness and efficiency of the proposed algorithms.
[ { "version": "v1", "created": "Mon, 24 Apr 2017 18:33:50 GMT" } ]
2017-04-26T00:00:00
[ [ "Ahmad", "Sabbir", "" ], [ "Kamal", "Rafi", "" ], [ "Ali", "Mohammed Eunus", "" ], [ "Qi", "Jianzhong", "" ], [ "Scheuermann", "Peter", "" ], [ "Tanin", "Egemen", "" ] ]
TITLE: The Flexible Group Spatial Keyword Query ABSTRACT: We present a new class of service for location based social networks, called the Flexible Group Spatial Keyword Query, which enables a group of users to collectively find a point of interest (POI) that optimizes an aggregate cost function combining both spatial distances and keyword similarities. In addition, our query service allows users to consider the tradeoffs between obtaining a sub-optimal solution for the entire group and obtaining an optimimized solution but only for a subgroup. We propose algorithms to process three variants of the query: (i) the group nearest neighbor with keywords query, which finds a POI that optimizes the aggregate cost function for the whole group of size n, (ii) the subgroup nearest neighbor with keywords query, which finds the optimal subgroup and a POI that optimizes the aggregate cost function for a given subgroup size m (m <= n), and (iii) the multiple subgroup nearest neighbor with keywords query, which finds optimal subgroups and corresponding POIs for each of the subgroup sizes in the range [m, n]. We design query processing algorithms based on branch-and-bound and best-first paradigms. Finally, we provide theoretical bounds and conduct extensive experiments with two real datasets which verify the effectiveness and efficiency of the proposed algorithms.
no_new_dataset
0.9463
1704.07461
Ashwin Pananjady
Ashwin Pananjady, Martin J. Wainwright, Thomas A. Courtade
Denoising Linear Models with Permuted Data
To appear in part at ISIT 2017, Aachen
null
null
null
stat.ML cs.IT math.IT math.ST stat.TH
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The multivariate linear regression model with shuffled data and additive Gaussian noise arises in various correspondence estimation and matching problems. Focusing on the denoising aspect of this problem, we provide a characterization the minimax error rate that is sharp up to logarithmic factors. We also analyze the performance of two versions of a computationally efficient estimator, and establish their consistency for a large range of input parameters. Finally, we provide an exact algorithm for the noiseless problem and demonstrate its performance on an image point-cloud matching task. Our analysis also extends to datasets with outliers.
[ { "version": "v1", "created": "Mon, 24 Apr 2017 20:46:48 GMT" } ]
2017-04-26T00:00:00
[ [ "Pananjady", "Ashwin", "" ], [ "Wainwright", "Martin J.", "" ], [ "Courtade", "Thomas A.", "" ] ]
TITLE: Denoising Linear Models with Permuted Data ABSTRACT: The multivariate linear regression model with shuffled data and additive Gaussian noise arises in various correspondence estimation and matching problems. Focusing on the denoising aspect of this problem, we provide a characterization the minimax error rate that is sharp up to logarithmic factors. We also analyze the performance of two versions of a computationally efficient estimator, and establish their consistency for a large range of input parameters. Finally, we provide an exact algorithm for the noiseless problem and demonstrate its performance on an image point-cloud matching task. Our analysis also extends to datasets with outliers.
no_new_dataset
0.947186
1704.07505
Feng Nan
Feng Nan and Venkatesh Saligrama
Dynamic Model Selection for Prediction Under a Budget
null
null
null
null
stat.ML cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a dynamic model selection approach for resource-constrained prediction. Given an input instance at test-time, a gating function identifies a prediction model for the input among a collection of models. Our objective is to minimize overall average cost without sacrificing accuracy. We learn gating and prediction models on fully labeled training data by means of a bottom-up strategy. Our novel bottom-up method is a recursive scheme whereby a high-accuracy complex model is first trained. Then a low-complexity gating and prediction model are subsequently learnt to adaptively approximate the high-accuracy model in regions where low-cost models are capable of making highly accurate predictions. We pose an empirical loss minimization problem with cost constraints to jointly train gating and prediction models. On a number of benchmark datasets our method outperforms state-of-the-art achieving higher accuracy for the same cost.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 01:17:22 GMT" } ]
2017-04-26T00:00:00
[ [ "Nan", "Feng", "" ], [ "Saligrama", "Venkatesh", "" ] ]
TITLE: Dynamic Model Selection for Prediction Under a Budget ABSTRACT: We present a dynamic model selection approach for resource-constrained prediction. Given an input instance at test-time, a gating function identifies a prediction model for the input among a collection of models. Our objective is to minimize overall average cost without sacrificing accuracy. We learn gating and prediction models on fully labeled training data by means of a bottom-up strategy. Our novel bottom-up method is a recursive scheme whereby a high-accuracy complex model is first trained. Then a low-complexity gating and prediction model are subsequently learnt to adaptively approximate the high-accuracy model in regions where low-cost models are capable of making highly accurate predictions. We pose an empirical loss minimization problem with cost constraints to jointly train gating and prediction models. On a number of benchmark datasets our method outperforms state-of-the-art achieving higher accuracy for the same cost.
no_new_dataset
0.947284
1704.07535
Maxim Rabinovich
Maxim Rabinovich, Mitchell Stern, Dan Klein
Abstract Syntax Networks for Code Generation and Semantic Parsing
ACL 2017. MR and MS contributed equally
null
null
null
cs.CL cs.AI cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Tasks like code generation and semantic parsing require mapping unstructured (or partially structured) inputs to well-formed, executable outputs. We introduce abstract syntax networks, a modeling framework for these problems. The outputs are represented as abstract syntax trees (ASTs) and constructed by a decoder with a dynamically-determined modular structure paralleling the structure of the output tree. On the benchmark Hearthstone dataset for code generation, our model obtains 79.2 BLEU and 22.7% exact match accuracy, compared to previous state-of-the-art values of 67.1 and 6.1%. Furthermore, we perform competitively on the Atis, Jobs, and Geo semantic parsing datasets with no task-specific engineering.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 04:37:35 GMT" } ]
2017-04-26T00:00:00
[ [ "Rabinovich", "Maxim", "" ], [ "Stern", "Mitchell", "" ], [ "Klein", "Dan", "" ] ]
TITLE: Abstract Syntax Networks for Code Generation and Semantic Parsing ABSTRACT: Tasks like code generation and semantic parsing require mapping unstructured (or partially structured) inputs to well-formed, executable outputs. We introduce abstract syntax networks, a modeling framework for these problems. The outputs are represented as abstract syntax trees (ASTs) and constructed by a decoder with a dynamically-determined modular structure paralleling the structure of the output tree. On the benchmark Hearthstone dataset for code generation, our model obtains 79.2 BLEU and 22.7% exact match accuracy, compared to previous state-of-the-art values of 67.1 and 6.1%. Furthermore, we perform competitively on the Atis, Jobs, and Geo semantic parsing datasets with no task-specific engineering.
no_new_dataset
0.953449
1704.07548
Huiguang He
Changde Du, Changying Du, Jinpeng Li, Wei-long Zheng, Bao-liang Lu, Huiguang He
Semi-supervised Bayesian Deep Multi-modal Emotion Recognition
null
null
null
null
cs.AI cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In emotion recognition, it is difficult to recognize human's emotional states using just a single modality. Besides, the annotation of physiological emotional data is particularly expensive. These two aspects make the building of effective emotion recognition model challenging. In this paper, we first build a multi-view deep generative model to simulate the generative process of multi-modality emotional data. By imposing a mixture of Gaussians assumption on the posterior approximation of the latent variables, our model can learn the shared deep representation from multiple modalities. To solve the labeled-data-scarcity problem, we further extend our multi-view model to semi-supervised learning scenario by casting the semi-supervised classification problem as a specialized missing data imputation task. Our semi-supervised multi-view deep generative framework can leverage both labeled and unlabeled data from multiple modalities, where the weight factor for each modality can be learned automatically. Compared with previous emotion recognition methods, our method is more robust and flexible. The experiments conducted on two real multi-modal emotion datasets have demonstrated the superiority of our framework over a number of competitors.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 06:29:59 GMT" } ]
2017-04-26T00:00:00
[ [ "Du", "Changde", "" ], [ "Du", "Changying", "" ], [ "Li", "Jinpeng", "" ], [ "Zheng", "Wei-long", "" ], [ "Lu", "Bao-liang", "" ], [ "He", "Huiguang", "" ] ]
TITLE: Semi-supervised Bayesian Deep Multi-modal Emotion Recognition ABSTRACT: In emotion recognition, it is difficult to recognize human's emotional states using just a single modality. Besides, the annotation of physiological emotional data is particularly expensive. These two aspects make the building of effective emotion recognition model challenging. In this paper, we first build a multi-view deep generative model to simulate the generative process of multi-modality emotional data. By imposing a mixture of Gaussians assumption on the posterior approximation of the latent variables, our model can learn the shared deep representation from multiple modalities. To solve the labeled-data-scarcity problem, we further extend our multi-view model to semi-supervised learning scenario by casting the semi-supervised classification problem as a specialized missing data imputation task. Our semi-supervised multi-view deep generative framework can leverage both labeled and unlabeled data from multiple modalities, where the weight factor for each modality can be learned automatically. Compared with previous emotion recognition methods, our method is more robust and flexible. The experiments conducted on two real multi-modal emotion datasets have demonstrated the superiority of our framework over a number of competitors.
no_new_dataset
0.945701
1704.07709
Md Zahangir Alom
Md Zahangir Alom, Mahmudul Hasan, Chris Yakopcic, Tarek M. Taha
Inception Recurrent Convolutional Neural Network for Object Recognition
11 pages, 10 figures, 2 tables
null
null
null
cs.CV
http://creativecommons.org/licenses/by/4.0/
Deep convolutional neural networks (DCNNs) are an influential tool for solving various problems in the machine learning and computer vision fields. In this paper, we introduce a new deep learning model called an Inception- Recurrent Convolutional Neural Network (IRCNN), which utilizes the power of an inception network combined with recurrent layers in DCNN architecture. We have empirically evaluated the recognition performance of the proposed IRCNN model using different benchmark datasets such as MNIST, CIFAR-10, CIFAR- 100, and SVHN. Experimental results show similar or higher recognition accuracy when compared to most of the popular DCNNs including the RCNN. Furthermore, we have investigated IRCNN performance against equivalent Inception Networks and Inception-Residual Networks using the CIFAR-100 dataset. We report about 3.5%, 3.47% and 2.54% improvement in classification accuracy when compared to the RCNN, equivalent Inception Networks, and Inception- Residual Networks on the augmented CIFAR- 100 dataset respectively.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 14:19:26 GMT" } ]
2017-04-26T00:00:00
[ [ "Alom", "Md Zahangir", "" ], [ "Hasan", "Mahmudul", "" ], [ "Yakopcic", "Chris", "" ], [ "Taha", "Tarek M.", "" ] ]
TITLE: Inception Recurrent Convolutional Neural Network for Object Recognition ABSTRACT: Deep convolutional neural networks (DCNNs) are an influential tool for solving various problems in the machine learning and computer vision fields. In this paper, we introduce a new deep learning model called an Inception- Recurrent Convolutional Neural Network (IRCNN), which utilizes the power of an inception network combined with recurrent layers in DCNN architecture. We have empirically evaluated the recognition performance of the proposed IRCNN model using different benchmark datasets such as MNIST, CIFAR-10, CIFAR- 100, and SVHN. Experimental results show similar or higher recognition accuracy when compared to most of the popular DCNNs including the RCNN. Furthermore, we have investigated IRCNN performance against equivalent Inception Networks and Inception-Residual Networks using the CIFAR-100 dataset. We report about 3.5%, 3.47% and 2.54% improvement in classification accuracy when compared to the RCNN, equivalent Inception Networks, and Inception- Residual Networks on the augmented CIFAR- 100 dataset respectively.
no_new_dataset
0.95418
1704.07751
Maxim Rabinovich
Maxim Rabinovich, Dan Klein
Fine-Grained Entity Typing with High-Multiplicity Assignments
ACL 2017
null
null
null
cs.CL cs.AI cs.IR cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
As entity type systems become richer and more fine-grained, we expect the number of types assigned to a given entity to increase. However, most fine-grained typing work has focused on datasets that exhibit a low degree of type multiplicity. In this paper, we consider the high-multiplicity regime inherent in data sources such as Wikipedia that have semi-open type systems. We introduce a set-prediction approach to this problem and show that our model outperforms unstructured baselines on a new Wikipedia-based fine-grained typing corpus.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 15:52:52 GMT" } ]
2017-04-26T00:00:00
[ [ "Rabinovich", "Maxim", "" ], [ "Klein", "Dan", "" ] ]
TITLE: Fine-Grained Entity Typing with High-Multiplicity Assignments ABSTRACT: As entity type systems become richer and more fine-grained, we expect the number of types assigned to a given entity to increase. However, most fine-grained typing work has focused on datasets that exhibit a low degree of type multiplicity. In this paper, we consider the high-multiplicity regime inherent in data sources such as Wikipedia that have semi-open type systems. We introduce a set-prediction approach to this problem and show that our model outperforms unstructured baselines on a new Wikipedia-based fine-grained typing corpus.
no_new_dataset
0.946448
1704.07790
Haoyi Xiong
Haoyi Xiong, Wei Cheng, Wenqing Hu, Jiang Bian, and Zhishan Guo
FWDA: a Fast Wishart Discriminant Analysis with its Application to Electronic Health Records Data Classification
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Linear Discriminant Analysis (LDA) on Electronic Health Records (EHR) data is widely-used for early detection of diseases. Classical LDA for EHR data classification, however, suffers from two handicaps: the ill-posed estimation of LDA parameters (e.g., covariance matrix), and the "linear inseparability" of EHR data. To handle these two issues, in this paper, we propose a novel classifier FWDA -- Fast Wishart Discriminant Analysis, that makes predictions in an ensemble way. Specifically, FWDA first surrogates the distribution of inverse covariance matrices using a Wishart distribution estimated from the training data, then "weighted-averages" the classification results of multiple LDA classifiers parameterized by the sampled inverse covariance matrices via a Bayesian Voting scheme. The weights for voting are optimally updated to adapt each new input data, so as to enable the nonlinear classification. Theoretical analysis indicates that FWDA possesses a fast convergence rate and a robust performance on high dimensional data. Extensive experiments on large-scale EHR dataset show that our approach outperforms state-of-the-art algorithms by a large margin.
[ { "version": "v1", "created": "Tue, 25 Apr 2017 17:11:57 GMT" } ]
2017-04-26T00:00:00
[ [ "Xiong", "Haoyi", "" ], [ "Cheng", "Wei", "" ], [ "Hu", "Wenqing", "" ], [ "Bian", "Jiang", "" ], [ "Guo", "Zhishan", "" ] ]
TITLE: FWDA: a Fast Wishart Discriminant Analysis with its Application to Electronic Health Records Data Classification ABSTRACT: Linear Discriminant Analysis (LDA) on Electronic Health Records (EHR) data is widely-used for early detection of diseases. Classical LDA for EHR data classification, however, suffers from two handicaps: the ill-posed estimation of LDA parameters (e.g., covariance matrix), and the "linear inseparability" of EHR data. To handle these two issues, in this paper, we propose a novel classifier FWDA -- Fast Wishart Discriminant Analysis, that makes predictions in an ensemble way. Specifically, FWDA first surrogates the distribution of inverse covariance matrices using a Wishart distribution estimated from the training data, then "weighted-averages" the classification results of multiple LDA classifiers parameterized by the sampled inverse covariance matrices via a Bayesian Voting scheme. The weights for voting are optimally updated to adapt each new input data, so as to enable the nonlinear classification. Theoretical analysis indicates that FWDA possesses a fast convergence rate and a robust performance on high dimensional data. Extensive experiments on large-scale EHR dataset show that our approach outperforms state-of-the-art algorithms by a large margin.
no_new_dataset
0.946448
1111.4470
Aryeh Kontorovich
Lee-Ad Gottlieb and Aryeh Kontorovich and Robert Krauthgamer
Efficient Regression in Metric Spaces via Approximate Lipschitz Extension
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present a framework for performing efficient regression in general metric spaces. Roughly speaking, our regressor predicts the value at a new point by computing a Lipschitz extension --- the smoothest function consistent with the observed data --- after performing structural risk minimization to avoid overfitting. We obtain finite-sample risk bounds with minimal structural and noise assumptions, and a natural speed-precision tradeoff. The offline (learning) and online (prediction) stages can be solved by convex programming, but this naive approach has runtime complexity $O(n^3)$, which is prohibitive for large datasets. We design instead a regression algorithm whose speed and generalization performance depend on the intrinsic dimension of the data, to which the algorithm adapts. While our main innovation is algorithmic, the statistical results may also be of independent interest.
[ { "version": "v1", "created": "Fri, 18 Nov 2011 20:32:33 GMT" }, { "version": "v2", "created": "Tue, 14 Jul 2015 17:06:29 GMT" }, { "version": "v3", "created": "Mon, 24 Apr 2017 07:56:53 GMT" } ]
2017-04-25T00:00:00
[ [ "Gottlieb", "Lee-Ad", "" ], [ "Kontorovich", "Aryeh", "" ], [ "Krauthgamer", "Robert", "" ] ]
TITLE: Efficient Regression in Metric Spaces via Approximate Lipschitz Extension ABSTRACT: We present a framework for performing efficient regression in general metric spaces. Roughly speaking, our regressor predicts the value at a new point by computing a Lipschitz extension --- the smoothest function consistent with the observed data --- after performing structural risk minimization to avoid overfitting. We obtain finite-sample risk bounds with minimal structural and noise assumptions, and a natural speed-precision tradeoff. The offline (learning) and online (prediction) stages can be solved by convex programming, but this naive approach has runtime complexity $O(n^3)$, which is prohibitive for large datasets. We design instead a regression algorithm whose speed and generalization performance depend on the intrinsic dimension of the data, to which the algorithm adapts. While our main innovation is algorithmic, the statistical results may also be of independent interest.
no_new_dataset
0.947672
1509.00104
Wenqiang Liu
Wenqiang Liu
Truth Discovery to Resolve Object Conflicts in Linked Data
Have many crucial faults in this version
null
null
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In the community of Linked Data, anyone can publish their data as Linked Data on the web because of the openness of the Semantic Web. As such, RDF (Resource Description Framework) triples described the same real-world entity can be obtained from multiple sources; it inevitably results in conflicting objects for a certain predicate of a real-world entity. The objective of this study is to identify one truth from multiple conflicting objects for a certain predicate of a real-world entity. An intuitive principle based on common sense is that an object from a reliable source is trustworthy; thus, a source that provide trustworthy object is reliable. Many truth discovery methods based on this principle have been proposed to estimate source reliability and identify the truth. However, the effectiveness of existing truth discovery methods is significantly affected by the number of objects provided by each source. Therefore, these methods cannot be trivially extended to resolve conflicts in Linked Data with a scale-free property, i.e., most of the sources provide few conflicting objects, whereas only a few sources have many conflicting objects. To address this challenge, we propose a novel approach called TruthDiscover to identify the truth in Linked Data with a scale-free property. Two strategies are adopted in TruthDiscover to reduce the effect of the scale-free property on truth discovery. First, this approach leverages the topological properties of the Source Belief Graph to estimate the priori beliefs of sources, which are utilized to smooth the trustworthiness of sources. Second, this approach utilizes the Hidden Markov Random Field to model the interdependencies between objects to estimate the trust values of objects accurately. Experiments are conducted in the six datasets to evaluate TruthDiscover.
[ { "version": "v1", "created": "Tue, 1 Sep 2015 00:58:16 GMT" }, { "version": "v2", "created": "Wed, 2 Sep 2015 00:40:30 GMT" }, { "version": "v3", "created": "Wed, 4 Nov 2015 00:56:14 GMT" }, { "version": "v4", "created": "Wed, 11 Nov 2015 12:00:26 GMT" }, { "version": "v5", "created": "Sat, 28 Nov 2015 09:38:52 GMT" }, { "version": "v6", "created": "Tue, 8 Mar 2016 02:10:02 GMT" }, { "version": "v7", "created": "Wed, 22 Feb 2017 21:34:06 GMT" }, { "version": "v8", "created": "Fri, 21 Apr 2017 22:46:34 GMT" } ]
2017-04-25T00:00:00
[ [ "Liu", "Wenqiang", "" ] ]
TITLE: Truth Discovery to Resolve Object Conflicts in Linked Data ABSTRACT: In the community of Linked Data, anyone can publish their data as Linked Data on the web because of the openness of the Semantic Web. As such, RDF (Resource Description Framework) triples described the same real-world entity can be obtained from multiple sources; it inevitably results in conflicting objects for a certain predicate of a real-world entity. The objective of this study is to identify one truth from multiple conflicting objects for a certain predicate of a real-world entity. An intuitive principle based on common sense is that an object from a reliable source is trustworthy; thus, a source that provide trustworthy object is reliable. Many truth discovery methods based on this principle have been proposed to estimate source reliability and identify the truth. However, the effectiveness of existing truth discovery methods is significantly affected by the number of objects provided by each source. Therefore, these methods cannot be trivially extended to resolve conflicts in Linked Data with a scale-free property, i.e., most of the sources provide few conflicting objects, whereas only a few sources have many conflicting objects. To address this challenge, we propose a novel approach called TruthDiscover to identify the truth in Linked Data with a scale-free property. Two strategies are adopted in TruthDiscover to reduce the effect of the scale-free property on truth discovery. First, this approach leverages the topological properties of the Source Belief Graph to estimate the priori beliefs of sources, which are utilized to smooth the trustworthiness of sources. Second, this approach utilizes the Hidden Markov Random Field to model the interdependencies between objects to estimate the trust values of objects accurately. Experiments are conducted in the six datasets to evaluate TruthDiscover.
no_new_dataset
0.950869