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1605.06047
Gerasimos Spanakis
Gerasimos Spanakis, Gerhard Weiss
AMSOM: Adaptive Moving Self-organizing Map for Clustering and Visualization
ICAART 2016 accepted full paper
null
10.5220/0005704801290140
null
cs.AI cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Self-Organizing Map (SOM) is a neural network model which is used to obtain a topology-preserving mapping from the (usually high dimensional) input/feature space to an output/map space of fewer dimensions (usually two or three in order to facilitate visualization). Neurons in the output space are connected with each other but this structure remains fixed throughout training and learning is achieved through the updating of neuron reference vectors in feature space. Despite the fact that growing variants of SOM overcome the fixed structure limitation they increase computational cost and also do not allow the removal of a neuron after its introduction. In this paper, a variant of SOM is proposed called AMSOM (Adaptive Moving Self-Organizing Map) that on the one hand creates a more flexible structure where neuron positions are dynamically altered during training and on the other hand tackles the drawback of having a predefined grid by allowing neuron addition and/or removal during training. Experiments using multiple literature datasets show that the proposed method improves training performance of SOM, leads to a better visualization of the input dataset and provides a framework for determining the optimal number and structure of neurons.
[ { "version": "v1", "created": "Thu, 19 May 2016 16:41:00 GMT" } ]
2016-05-20T00:00:00
[ [ "Spanakis", "Gerasimos", "" ], [ "Weiss", "Gerhard", "" ] ]
TITLE: AMSOM: Adaptive Moving Self-organizing Map for Clustering and Visualization ABSTRACT: Self-Organizing Map (SOM) is a neural network model which is used to obtain a topology-preserving mapping from the (usually high dimensional) input/feature space to an output/map space of fewer dimensions (usually two or three in order to facilitate visualization). Neurons in the output space are connected with each other but this structure remains fixed throughout training and learning is achieved through the updating of neuron reference vectors in feature space. Despite the fact that growing variants of SOM overcome the fixed structure limitation they increase computational cost and also do not allow the removal of a neuron after its introduction. In this paper, a variant of SOM is proposed called AMSOM (Adaptive Moving Self-Organizing Map) that on the one hand creates a more flexible structure where neuron positions are dynamically altered during training and on the other hand tackles the drawback of having a predefined grid by allowing neuron addition and/or removal during training. Experiments using multiple literature datasets show that the proposed method improves training performance of SOM, leads to a better visualization of the input dataset and provides a framework for determining the optimal number and structure of neurons.
1605.06052
Jason Grant
Jason Grant and Patrick Flynn
Hierarchical Clustering in Face Similarity Score Space
5 pages, 3 figures
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Similarity scores in face recognition represent the proximity between pairs of images as computed by a matching algorithm. Given a large set of images and the proximities between all pairs, a similarity score space is defined. Cluster analysis was applied to the similarity score space to develop various taxonomies. Given the number of subjects in the dataset, we used hierarchical methods to aggregate images of the same subject. We also explored the hierarchy above and below the subject level, including clusters that reflect gender and ethnicity. Evidence supports the existence of clustering by race, gender, subject, and illumination condition.
[ { "version": "v1", "created": "Thu, 19 May 2016 17:08:16 GMT" } ]
2016-05-20T00:00:00
[ [ "Grant", "Jason", "" ], [ "Flynn", "Patrick", "" ] ]
TITLE: Hierarchical Clustering in Face Similarity Score Space ABSTRACT: Similarity scores in face recognition represent the proximity between pairs of images as computed by a matching algorithm. Given a large set of images and the proximities between all pairs, a similarity score space is defined. Cluster analysis was applied to the similarity score space to develop various taxonomies. Given the number of subjects in the dataset, we used hierarchical methods to aggregate images of the same subject. We also explored the hierarchy above and below the subject level, including clusters that reflect gender and ethnicity. Evidence supports the existence of clustering by race, gender, subject, and illumination condition.
1605.06083
Emiel van Miltenburg
Emiel van Miltenburg
Stereotyping and Bias in the Flickr30K Dataset
In: Proceedings of the Workshop on Multimodal Corpora (MMC-2016), pages 1-4. Editors: Jens Edlund, Dirk Heylen and Patrizia Paggio
null
null
null
cs.CL cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An untested assumption behind the crowdsourced descriptions of the images in the Flickr30K dataset (Young et al., 2014) is that they "focus only on the information that can be obtained from the image alone" (Hodosh et al., 2013, p. 859). This paper presents some evidence against this assumption, and provides a list of biases and unwarranted inferences that can be found in the Flickr30K dataset. Finally, it considers methods to find examples of these, and discusses how we should deal with stereotype-driven descriptions in future applications.
[ { "version": "v1", "created": "Thu, 19 May 2016 19:17:23 GMT" } ]
2016-05-20T00:00:00
[ [ "van Miltenburg", "Emiel", "" ] ]
TITLE: Stereotyping and Bias in the Flickr30K Dataset ABSTRACT: An untested assumption behind the crowdsourced descriptions of the images in the Flickr30K dataset (Young et al., 2014) is that they "focus only on the information that can be obtained from the image alone" (Hodosh et al., 2013, p. 859). This paper presents some evidence against this assumption, and provides a list of biases and unwarranted inferences that can be found in the Flickr30K dataset. Finally, it considers methods to find examples of these, and discusses how we should deal with stereotype-driven descriptions in future applications.
1605.00287
Xiang Xiang
Minh Dao, Xiang Xiang, Bulent Ayhan, Chiman Kwan, Trac D. Tran
Detecting Burnscar from Hyperspectral Imagery via Sparse Representation with Low-Rank Interference
It is not a publishable version at this point as there is no IP coverage at the moment
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we propose a burnscar detection model for hyperspectral imaging (HSI) data. The proposed model contains two-processing steps in which the first step separate and then suppress the cloud information presenting in the data set using an RPCA algorithm and the second step detect the burnscar area in the low-rank component output of the first step. Experiments are conducted on the public MODIS dataset available at NASA official website.
[ { "version": "v1", "created": "Sun, 1 May 2016 18:18:45 GMT" }, { "version": "v2", "created": "Tue, 17 May 2016 23:25:22 GMT" } ]
2016-05-19T00:00:00
[ [ "Dao", "Minh", "" ], [ "Xiang", "Xiang", "" ], [ "Ayhan", "Bulent", "" ], [ "Kwan", "Chiman", "" ], [ "Tran", "Trac D.", "" ] ]
TITLE: Detecting Burnscar from Hyperspectral Imagery via Sparse Representation with Low-Rank Interference ABSTRACT: In this paper, we propose a burnscar detection model for hyperspectral imaging (HSI) data. The proposed model contains two-processing steps in which the first step separate and then suppress the cloud information presenting in the data set using an RPCA algorithm and the second step detect the burnscar area in the low-rank component output of the first step. Experiments are conducted on the public MODIS dataset available at NASA official website.
1605.04652
Anand Padmanabha Iyer
Anand Padmanabha Iyer, Ion Stoica, Mosharaf Chowdhury, Li Erran Li
Fast and Accurate Performance Analysis of LTE Radio Access Networks
null
null
null
null
cs.DC cs.LG cs.NI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An increasing amount of analytics is performed on data that is procured in a real-time fashion to make real-time decisions. Such tasks include simple reporting on streams to sophisticated model building. However, the practicality of such analyses are impeded in several domains because they are faced with a fundamental trade-off between data collection latency and analysis accuracy. In this paper, we study this trade-off in the context of a specific domain, Cellular Radio Access Networks (RAN). Our choice of this domain is influenced by its commonalities with several other domains that produce real-time data, our access to a large live dataset, and their real-time nature and dimensionality which makes it a natural fit for a popular analysis technique, machine learning (ML). We find that the latency accuracy trade-off can be resolved using two broad, general techniques: intelligent data grouping and task formulations that leverage domain characteristics. Based on this, we present CellScope, a system that addresses this challenge by applying a domain specific formulation and application of Multi-task Learning (MTL) to RAN performance analysis. It achieves this goal using three techniques: feature engineering to transform raw data into effective features, a PCA inspired similarity metric to group data from geographically nearby base stations sharing performance commonalities, and a hybrid online-offline model for efficient model updates. Our evaluation of CellScope shows that its accuracy improvements over direct application of ML range from 2.5x to 4.4x while reducing the model update overhead by up to 4.8x. We have also used CellScope to analyze a live LTE consisting of over 2 million subscribers for a period of over 10 months, where it uncovered several problems and insights, some of them previously unknown.
[ { "version": "v1", "created": "Mon, 16 May 2016 05:31:01 GMT" }, { "version": "v2", "created": "Tue, 17 May 2016 20:00:59 GMT" } ]
2016-05-19T00:00:00
[ [ "Iyer", "Anand Padmanabha", "" ], [ "Stoica", "Ion", "" ], [ "Chowdhury", "Mosharaf", "" ], [ "Li", "Li Erran", "" ] ]
TITLE: Fast and Accurate Performance Analysis of LTE Radio Access Networks ABSTRACT: An increasing amount of analytics is performed on data that is procured in a real-time fashion to make real-time decisions. Such tasks include simple reporting on streams to sophisticated model building. However, the practicality of such analyses are impeded in several domains because they are faced with a fundamental trade-off between data collection latency and analysis accuracy. In this paper, we study this trade-off in the context of a specific domain, Cellular Radio Access Networks (RAN). Our choice of this domain is influenced by its commonalities with several other domains that produce real-time data, our access to a large live dataset, and their real-time nature and dimensionality which makes it a natural fit for a popular analysis technique, machine learning (ML). We find that the latency accuracy trade-off can be resolved using two broad, general techniques: intelligent data grouping and task formulations that leverage domain characteristics. Based on this, we present CellScope, a system that addresses this challenge by applying a domain specific formulation and application of Multi-task Learning (MTL) to RAN performance analysis. It achieves this goal using three techniques: feature engineering to transform raw data into effective features, a PCA inspired similarity metric to group data from geographically nearby base stations sharing performance commonalities, and a hybrid online-offline model for efficient model updates. Our evaluation of CellScope shows that its accuracy improvements over direct application of ML range from 2.5x to 4.4x while reducing the model update overhead by up to 4.8x. We have also used CellScope to analyze a live LTE consisting of over 2 million subscribers for a period of over 10 months, where it uncovered several problems and insights, some of them previously unknown.
1605.05362
Nabiha Asghar
Nabiha Asghar
Yelp Dataset Challenge: Review Rating Prediction
null
null
null
null
cs.CL cs.IR cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Review websites, such as TripAdvisor and Yelp, allow users to post online reviews for various businesses, products and services, and have been recently shown to have a significant influence on consumer shopping behaviour. An online review typically consists of free-form text and a star rating out of 5. The problem of predicting a user's star rating for a product, given the user's text review for that product, is called Review Rating Prediction and has lately become a popular, albeit hard, problem in machine learning. In this paper, we treat Review Rating Prediction as a multi-class classification problem, and build sixteen different prediction models by combining four feature extraction methods, (i) unigrams, (ii) bigrams, (iii) trigrams and (iv) Latent Semantic Indexing, with four machine learning algorithms, (i) logistic regression, (ii) Naive Bayes classification, (iii) perceptrons, and (iv) linear Support Vector Classification. We analyse the performance of each of these sixteen models to come up with the best model for predicting the ratings from reviews. We use the dataset provided by Yelp for training and testing the models.
[ { "version": "v1", "created": "Tue, 17 May 2016 20:52:33 GMT" } ]
2016-05-19T00:00:00
[ [ "Asghar", "Nabiha", "" ] ]
TITLE: Yelp Dataset Challenge: Review Rating Prediction ABSTRACT: Review websites, such as TripAdvisor and Yelp, allow users to post online reviews for various businesses, products and services, and have been recently shown to have a significant influence on consumer shopping behaviour. An online review typically consists of free-form text and a star rating out of 5. The problem of predicting a user's star rating for a product, given the user's text review for that product, is called Review Rating Prediction and has lately become a popular, albeit hard, problem in machine learning. In this paper, we treat Review Rating Prediction as a multi-class classification problem, and build sixteen different prediction models by combining four feature extraction methods, (i) unigrams, (ii) bigrams, (iii) trigrams and (iv) Latent Semantic Indexing, with four machine learning algorithms, (i) logistic regression, (ii) Naive Bayes classification, (iii) perceptrons, and (iv) linear Support Vector Classification. We analyse the performance of each of these sixteen models to come up with the best model for predicting the ratings from reviews. We use the dataset provided by Yelp for training and testing the models.
1605.05395
Scott Reed
Scott Reed, Zeynep Akata, Bernt Schiele, Honglak Lee
Learning Deep Representations of Fine-grained Visual Descriptions
CVPR 2016
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
State-of-the-art methods for zero-shot visual recognition formulate learning as a joint embedding problem of images and side information. In these formulations the current best complement to visual features are attributes: manually encoded vectors describing shared characteristics among categories. Despite good performance, attributes have limitations: (1) finer-grained recognition requires commensurately more attributes, and (2) attributes do not provide a natural language interface. We propose to overcome these limitations by training neural language models from scratch; i.e. without pre-training and only consuming words and characters. Our proposed models train end-to-end to align with the fine-grained and category-specific content of images. Natural language provides a flexible and compact way of encoding only the salient visual aspects for distinguishing categories. By training on raw text, our model can do inference on raw text as well, providing humans a familiar mode both for annotation and retrieval. Our model achieves strong performance on zero-shot text-based image retrieval and significantly outperforms the attribute-based state-of-the-art for zero-shot classification on the Caltech UCSD Birds 200-2011 dataset.
[ { "version": "v1", "created": "Tue, 17 May 2016 23:08:46 GMT" } ]
2016-05-19T00:00:00
[ [ "Reed", "Scott", "" ], [ "Akata", "Zeynep", "" ], [ "Schiele", "Bernt", "" ], [ "Lee", "Honglak", "" ] ]
TITLE: Learning Deep Representations of Fine-grained Visual Descriptions ABSTRACT: State-of-the-art methods for zero-shot visual recognition formulate learning as a joint embedding problem of images and side information. In these formulations the current best complement to visual features are attributes: manually encoded vectors describing shared characteristics among categories. Despite good performance, attributes have limitations: (1) finer-grained recognition requires commensurately more attributes, and (2) attributes do not provide a natural language interface. We propose to overcome these limitations by training neural language models from scratch; i.e. without pre-training and only consuming words and characters. Our proposed models train end-to-end to align with the fine-grained and category-specific content of images. Natural language provides a flexible and compact way of encoding only the salient visual aspects for distinguishing categories. By training on raw text, our model can do inference on raw text as well, providing humans a familiar mode both for annotation and retrieval. Our model achieves strong performance on zero-shot text-based image retrieval and significantly outperforms the attribute-based state-of-the-art for zero-shot classification on the Caltech UCSD Birds 200-2011 dataset.
1605.05401
Yu Wang
Yu Wang, Yang Feng, Yuncheng Li, Xiyang Zhang, Richard Niemi, Jiebo Luo
Pricing the Woman Card: Gender Politics between Hillary Clinton and Donald Trump
4 pages, 6 figures, 7 tables, under review
null
null
null
cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we propose a data-driven method to measure the impact of the 'woman card' exchange between Hillary Clinton and Donald Trump. Building from a unique dataset of the two candidates' Twitter followers, we first examine the transition dynamics of the two candidates' Twitter followers one week before the exchange and one week after. Then we train a convolutional neural network to classify the gender of the followers and unfollowers, and study how women in particular are reacting to the 'woman card' exchange. Our study suggests that the 'woman card' comment has made women more likely to follow Hillary Clinton, less likely to unfollow her and that it has apparently not affected the gender composition of Trump followers.
[ { "version": "v1", "created": "Wed, 18 May 2016 00:00:44 GMT" } ]
2016-05-19T00:00:00
[ [ "Wang", "Yu", "" ], [ "Feng", "Yang", "" ], [ "Li", "Yuncheng", "" ], [ "Zhang", "Xiyang", "" ], [ "Niemi", "Richard", "" ], [ "Luo", "Jiebo", "" ] ]
TITLE: Pricing the Woman Card: Gender Politics between Hillary Clinton and Donald Trump ABSTRACT: In this paper, we propose a data-driven method to measure the impact of the 'woman card' exchange between Hillary Clinton and Donald Trump. Building from a unique dataset of the two candidates' Twitter followers, we first examine the transition dynamics of the two candidates' Twitter followers one week before the exchange and one week after. Then we train a convolutional neural network to classify the gender of the followers and unfollowers, and study how women in particular are reacting to the 'woman card' exchange. Our study suggests that the 'woman card' comment has made women more likely to follow Hillary Clinton, less likely to unfollow her and that it has apparently not affected the gender composition of Trump followers.
1605.05416
Ryan Lowe T.
Teng Long, Ryan Lowe, Jackie Chi Kit Cheung, Doina Precup
Leveraging Lexical Resources for Learning Entity Embeddings in Multi-Relational Data
6 pages. Accepted to ACL 2016 (short paper)
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Recent work in learning vector-space embeddings for multi-relational data has focused on combining relational information derived from knowledge bases with distributional information derived from large text corpora. We propose a simple approach that leverages the descriptions of entities or phrases available in lexical resources, in conjunction with distributional semantics, in order to derive a better initialization for training relational models. Applying this initialization to the TransE model results in significant new state-of-the-art performances on the WordNet dataset, decreasing the mean rank from the previous best of 212 to 51. It also results in faster convergence of the entity representations. We find that there is a trade-off between improving the mean rank and the hits@10 with this approach. This illustrates that much remains to be understood regarding performance improvements in relational models.
[ { "version": "v1", "created": "Wed, 18 May 2016 01:45:32 GMT" } ]
2016-05-19T00:00:00
[ [ "Long", "Teng", "" ], [ "Lowe", "Ryan", "" ], [ "Cheung", "Jackie Chi Kit", "" ], [ "Precup", "Doina", "" ] ]
TITLE: Leveraging Lexical Resources for Learning Entity Embeddings in Multi-Relational Data ABSTRACT: Recent work in learning vector-space embeddings for multi-relational data has focused on combining relational information derived from knowledge bases with distributional information derived from large text corpora. We propose a simple approach that leverages the descriptions of entities or phrases available in lexical resources, in conjunction with distributional semantics, in order to derive a better initialization for training relational models. Applying this initialization to the TransE model results in significant new state-of-the-art performances on the WordNet dataset, decreasing the mean rank from the previous best of 212 to 51. It also results in faster convergence of the entity representations. We find that there is a trade-off between improving the mean rank and the hits@10 with this approach. This illustrates that much remains to be understood regarding performance improvements in relational models.
1605.05436
Michael Goodrich
Michael T. Goodrich, Ahmed Eldawy
Parallel Algorithms for Summing Floating-Point Numbers
Conference version appears in SPAA 2016
null
null
null
cs.DS cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The problem of exactly summing n floating-point numbers is a fundamental problem that has many applications in large-scale simulations and computational geometry. Unfortunately, due to the round-off error in standard floating-point operations, this problem becomes very challenging. Moreover, all existing solutions rely on sequential algorithms which cannot scale to the huge datasets that need to be processed. In this paper, we provide several efficient parallel algorithms for summing n floating point numbers, so as to produce a faithfully rounded floating-point representation of the sum. We present algorithms in PRAM, external-memory, and MapReduce models, and we also provide an experimental analysis of our MapReduce algorithms, due to their simplicity and practical efficiency.
[ { "version": "v1", "created": "Wed, 18 May 2016 04:20:41 GMT" } ]
2016-05-19T00:00:00
[ [ "Goodrich", "Michael T.", "" ], [ "Eldawy", "Ahmed", "" ] ]
TITLE: Parallel Algorithms for Summing Floating-Point Numbers ABSTRACT: The problem of exactly summing n floating-point numbers is a fundamental problem that has many applications in large-scale simulations and computational geometry. Unfortunately, due to the round-off error in standard floating-point operations, this problem becomes very challenging. Moreover, all existing solutions rely on sequential algorithms which cannot scale to the huge datasets that need to be processed. In this paper, we provide several efficient parallel algorithms for summing n floating point numbers, so as to produce a faithfully rounded floating-point representation of the sum. We present algorithms in PRAM, external-memory, and MapReduce models, and we also provide an experimental analysis of our MapReduce algorithms, due to their simplicity and practical efficiency.
1605.05462
Marius Leordeanu
Alina Marcu and Marius Leordeanu
Dual Local-Global Contextual Pathways for Recognition in Aerial Imagery
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Visual context is important in object recognition and it is still an open problem in computer vision. Along with the advent of deep convolutional neural networks (CNN), using contextual information with such systems starts to receive attention in the literature. At the same time, aerial imagery is gaining momentum. While advances in deep learning make good progress in aerial image analysis, this problem still poses many great challenges. Aerial images are often taken under poor lighting conditions and contain low resolution objects, many times occluded by trees or taller buildings. In this domain, in particular, visual context could be of great help, but there are still very few papers that consider context in aerial image understanding. Here we introduce context as a complementary way of recognizing objects. We propose a dual-stream deep neural network model that processes information along two independent pathways, one for local and another for global visual reasoning. The two are later combined in the final layers of processing. Our model learns to combine local object appearance as well as information from the larger scene at the same time and in a complementary way, such that together they form a powerful classifier. We test our dual-stream network on the task of segmentation of buildings and roads in aerial images and obtain state-of-the-art results on the Massachusetts Buildings Dataset. We also introduce two new datasets, for buildings and road segmentation, respectively, and study the relative importance of local appearance vs. the larger scene, as well as their performance in combination. While our local-global model could also be useful in general recognition tasks, we clearly demonstrate the effectiveness of visual context in conjunction with deep nets for aerial image understanding.
[ { "version": "v1", "created": "Wed, 18 May 2016 07:37:22 GMT" } ]
2016-05-19T00:00:00
[ [ "Marcu", "Alina", "" ], [ "Leordeanu", "Marius", "" ] ]
TITLE: Dual Local-Global Contextual Pathways for Recognition in Aerial Imagery ABSTRACT: Visual context is important in object recognition and it is still an open problem in computer vision. Along with the advent of deep convolutional neural networks (CNN), using contextual information with such systems starts to receive attention in the literature. At the same time, aerial imagery is gaining momentum. While advances in deep learning make good progress in aerial image analysis, this problem still poses many great challenges. Aerial images are often taken under poor lighting conditions and contain low resolution objects, many times occluded by trees or taller buildings. In this domain, in particular, visual context could be of great help, but there are still very few papers that consider context in aerial image understanding. Here we introduce context as a complementary way of recognizing objects. We propose a dual-stream deep neural network model that processes information along two independent pathways, one for local and another for global visual reasoning. The two are later combined in the final layers of processing. Our model learns to combine local object appearance as well as information from the larger scene at the same time and in a complementary way, such that together they form a powerful classifier. We test our dual-stream network on the task of segmentation of buildings and roads in aerial images and obtain state-of-the-art results on the Massachusetts Buildings Dataset. We also introduce two new datasets, for buildings and road segmentation, respectively, and study the relative importance of local appearance vs. the larger scene, as well as their performance in combination. While our local-global model could also be useful in general recognition tasks, we clearly demonstrate the effectiveness of visual context in conjunction with deep nets for aerial image understanding.
1605.05466
Jeremiah Deng
Xianbin Gu, Jeremiah D. Deng, Martin K. Purvis
Image segmentation with superpixel-based covariance descriptors in low-rank representation
7 pages, 2 figures, 1 table
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper investigates the problem of image segmentation using superpixels. We propose two approaches to enhance the discriminative ability of the superpixel's covariance descriptors. In the first one, we employ the Log-Euclidean distance as the metric on the covariance manifolds, and then use the RBF kernel to measure the similarities between covariance descriptors. The second method is focused on extracting the subspace structure of the set of covariance descriptors by extending a low rank representation algorithm on to the covariance manifolds. Experiments are carried out with the Berkly Segmentation Dataset, and compared with the state-of-the-art segmentation algorithms, both methods are competitive.
[ { "version": "v1", "created": "Wed, 18 May 2016 07:44:38 GMT" } ]
2016-05-19T00:00:00
[ [ "Gu", "Xianbin", "" ], [ "Deng", "Jeremiah D.", "" ], [ "Purvis", "Martin K.", "" ] ]
TITLE: Image segmentation with superpixel-based covariance descriptors in low-rank representation ABSTRACT: This paper investigates the problem of image segmentation using superpixels. We propose two approaches to enhance the discriminative ability of the superpixel's covariance descriptors. In the first one, we employ the Log-Euclidean distance as the metric on the covariance manifolds, and then use the RBF kernel to measure the similarities between covariance descriptors. The second method is focused on extracting the subspace structure of the set of covariance descriptors by extending a low rank representation algorithm on to the covariance manifolds. Experiments are carried out with the Berkly Segmentation Dataset, and compared with the state-of-the-art segmentation algorithms, both methods are competitive.
1605.05538
Alexander Kolesnikov
Alexander Kolesnikov and Christoph H. Lampert
Improving Weakly-Supervised Object Localization By Micro-Annotation
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Weakly-supervised object localization methods tend to fail for object classes that consistently co-occur with the same background elements, e.g. trains on tracks. We propose a method to overcome these failures by adding a very small amount of model-specific additional annotation. The main idea is to cluster a deep network's mid-level representations and assign object or distractor labels to each cluster. Experiments show substantially improved localization results on the challenging ILSVC2014 dataset for bounding box detection and the PASCAL VOC2012 dataset for semantic segmentation.
[ { "version": "v1", "created": "Wed, 18 May 2016 12:06:35 GMT" } ]
2016-05-19T00:00:00
[ [ "Kolesnikov", "Alexander", "" ], [ "Lampert", "Christoph H.", "" ] ]
TITLE: Improving Weakly-Supervised Object Localization By Micro-Annotation ABSTRACT: Weakly-supervised object localization methods tend to fail for object classes that consistently co-occur with the same background elements, e.g. trains on tracks. We propose a method to overcome these failures by adding a very small amount of model-specific additional annotation. The main idea is to cluster a deep network's mid-level representations and assign object or distractor labels to each cluster. Experiments show substantially improved localization results on the challenging ILSVC2014 dataset for bounding box detection and the PASCAL VOC2012 dataset for semantic segmentation.
1603.06127
Petr Baudi\v{s}
Petr Baudi\v{s}, Jan Pichl, Tom\'a\v{s} Vysko\v{c}il, Jan \v{S}ediv\'y
Sentence Pair Scoring: Towards Unified Framework for Text Comprehension
submitted as paper to CoNLL 2016
null
null
null
cs.CL cs.AI cs.LG cs.NE
http://creativecommons.org/licenses/by/4.0/
We review the task of Sentence Pair Scoring, popular in the literature in various forms - viewed as Answer Sentence Selection, Semantic Text Scoring, Next Utterance Ranking, Recognizing Textual Entailment, Paraphrasing or e.g. a component of Memory Networks. We argue that all such tasks are similar from the model perspective and propose new baselines by comparing the performance of common IR metrics and popular convolutional, recurrent and attention-based neural models across many Sentence Pair Scoring tasks and datasets. We discuss the problem of evaluating randomized models, propose a statistically grounded methodology, and attempt to improve comparisons by releasing new datasets that are much harder than some of the currently used well explored benchmarks. We introduce a unified open source software framework with easily pluggable models and tasks, which enables us to experiment with multi-task reusability of trained sentence model. We set a new state-of-art in performance on the Ubuntu Dialogue dataset.
[ { "version": "v1", "created": "Sat, 19 Mar 2016 18:35:26 GMT" }, { "version": "v2", "created": "Thu, 28 Apr 2016 03:10:26 GMT" }, { "version": "v3", "created": "Fri, 6 May 2016 22:17:36 GMT" }, { "version": "v4", "created": "Tue, 17 May 2016 14:08:38 GMT" } ]
2016-05-18T00:00:00
[ [ "Baudiš", "Petr", "" ], [ "Pichl", "Jan", "" ], [ "Vyskočil", "Tomáš", "" ], [ "Šedivý", "Jan", "" ] ]
TITLE: Sentence Pair Scoring: Towards Unified Framework for Text Comprehension ABSTRACT: We review the task of Sentence Pair Scoring, popular in the literature in various forms - viewed as Answer Sentence Selection, Semantic Text Scoring, Next Utterance Ranking, Recognizing Textual Entailment, Paraphrasing or e.g. a component of Memory Networks. We argue that all such tasks are similar from the model perspective and propose new baselines by comparing the performance of common IR metrics and popular convolutional, recurrent and attention-based neural models across many Sentence Pair Scoring tasks and datasets. We discuss the problem of evaluating randomized models, propose a statistically grounded methodology, and attempt to improve comparisons by releasing new datasets that are much harder than some of the currently used well explored benchmarks. We introduce a unified open source software framework with easily pluggable models and tasks, which enables us to experiment with multi-task reusability of trained sentence model. We set a new state-of-art in performance on the Ubuntu Dialogue dataset.
1605.01775
Andras Rozsa
Andras Rozsa, Ethan M. Rudd, and Terrance E. Boult
Adversarial Diversity and Hard Positive Generation
Accepted to CVPR 2016 DeepVision Workshop
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
State-of-the-art deep neural networks suffer from a fundamental problem - they misclassify adversarial examples formed by applying small perturbations to inputs. In this paper, we present a new psychometric perceptual adversarial similarity score (PASS) measure for quantifying adversarial images, introduce the notion of hard positive generation, and use a diverse set of adversarial perturbations - not just the closest ones - for data augmentation. We introduce a novel hot/cold approach for adversarial example generation, which provides multiple possible adversarial perturbations for every single image. The perturbations generated by our novel approach often correspond to semantically meaningful image structures, and allow greater flexibility to scale perturbation-amplitudes, which yields an increased diversity of adversarial images. We present adversarial images on several network topologies and datasets, including LeNet on the MNIST dataset, and GoogLeNet and ResidualNet on the ImageNet dataset. Finally, we demonstrate on LeNet and GoogLeNet that fine-tuning with a diverse set of hard positives improves the robustness of these networks compared to training with prior methods of generating adversarial images.
[ { "version": "v1", "created": "Thu, 5 May 2016 22:09:35 GMT" }, { "version": "v2", "created": "Tue, 17 May 2016 02:46:39 GMT" } ]
2016-05-18T00:00:00
[ [ "Rozsa", "Andras", "" ], [ "Rudd", "Ethan M.", "" ], [ "Boult", "Terrance E.", "" ] ]
TITLE: Adversarial Diversity and Hard Positive Generation ABSTRACT: State-of-the-art deep neural networks suffer from a fundamental problem - they misclassify adversarial examples formed by applying small perturbations to inputs. In this paper, we present a new psychometric perceptual adversarial similarity score (PASS) measure for quantifying adversarial images, introduce the notion of hard positive generation, and use a diverse set of adversarial perturbations - not just the closest ones - for data augmentation. We introduce a novel hot/cold approach for adversarial example generation, which provides multiple possible adversarial perturbations for every single image. The perturbations generated by our novel approach often correspond to semantically meaningful image structures, and allow greater flexibility to scale perturbation-amplitudes, which yields an increased diversity of adversarial images. We present adversarial images on several network topologies and datasets, including LeNet on the MNIST dataset, and GoogLeNet and ResidualNet on the ImageNet dataset. Finally, we demonstrate on LeNet and GoogLeNet that fine-tuning with a diverse set of hard positives improves the robustness of these networks compared to training with prior methods of generating adversarial images.
1605.04932
Frosti Palsson
Magnus O. Ulfarsson, Frosti Palsson, Jakob Sigurdsson and Johannes R. Sveinsson
Classification of Big Data with Application to Imaging Genetics
null
null
null
null
physics.data-an cs.CV stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Big data applications, such as medical imaging and genetics, typically generate datasets that consist of few observations n on many more variables p, a scenario that we denote as p>>n. Traditional data processing methods are often insufficient for extracting information out of big data. This calls for the development of new algorithms that can deal with the size, complexity, and the special structure of such datasets. In this paper, we consider the problem of classifying p>>n data and propose a classification method based on linear discriminant analysis (LDA). Traditional LDA depends on the covariance estimate of the data, but when p>>n the sample covariance estimate is singular. The proposed method estimates the covariance by using a sparse version of noisy principal component analysis (nPCA). The use of sparsity in this setting aims at automatically selecting variables that are relevant for classification. In experiments, the new method is compared to state-of-the art methods for big data problems using both simulated datasets and imaging genetics datasets.
[ { "version": "v1", "created": "Mon, 16 May 2016 20:16:29 GMT" } ]
2016-05-18T00:00:00
[ [ "Ulfarsson", "Magnus O.", "" ], [ "Palsson", "Frosti", "" ], [ "Sigurdsson", "Jakob", "" ], [ "Sveinsson", "Johannes R.", "" ] ]
TITLE: Classification of Big Data with Application to Imaging Genetics ABSTRACT: Big data applications, such as medical imaging and genetics, typically generate datasets that consist of few observations n on many more variables p, a scenario that we denote as p>>n. Traditional data processing methods are often insufficient for extracting information out of big data. This calls for the development of new algorithms that can deal with the size, complexity, and the special structure of such datasets. In this paper, we consider the problem of classifying p>>n data and propose a classification method based on linear discriminant analysis (LDA). Traditional LDA depends on the covariance estimate of the data, but when p>>n the sample covariance estimate is singular. The proposed method estimates the covariance by using a sparse version of noisy principal component analysis (nPCA). The use of sparsity in this setting aims at automatically selecting variables that are relevant for classification. In experiments, the new method is compared to state-of-the art methods for big data problems using both simulated datasets and imaging genetics datasets.
1605.04934
Fei Han
Fei Han, Christopher Reardon, Lynne E. Parker, Hao Zhang
Self-Reflective Risk-Aware Artificial Cognitive Modeling for Robot Response to Human Behaviors
40 pages
null
null
null
cs.RO cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In order for cooperative robots ("co-robots") to respond to human behaviors accurately and efficiently in human-robot collaboration, interpretation of human actions, awareness of new situations, and appropriate decision making are all crucial abilities for co-robots. For this purpose, the human behaviors should be interpreted by co-robots in the same manner as human peers. To address this issue, a novel interpretability indicator is introduced so that robot actions are appropriate to the current human behaviors. In addition, the complete consideration of all potential situations of a robot's environment is nearly impossible in real-world applications, making it difficult for the co-robot to act appropriately and safely in new scenarios. This is true even when the pretrained model is highly accurate in a known situation. For effective and safe teaming with humans, we introduce a new generalizability indicator that allows a co-robot to self-reflect and reason about when an observation falls outside the co-robot's learned model. Based on topic modeling and two novel indicators, we propose a new Self-reflective Risk-aware Artificial Cognitive (SRAC) model. The co-robots are able to consider action risks and identify new situations so that better decisions can be made. Experiments both using real-world datasets and on physical robots suggest that our SRAC model significantly outperforms the traditional methodology and enables better decision making in response to human activities.
[ { "version": "v1", "created": "Mon, 16 May 2016 20:22:30 GMT" } ]
2016-05-18T00:00:00
[ [ "Han", "Fei", "" ], [ "Reardon", "Christopher", "" ], [ "Parker", "Lynne E.", "" ], [ "Zhang", "Hao", "" ] ]
TITLE: Self-Reflective Risk-Aware Artificial Cognitive Modeling for Robot Response to Human Behaviors ABSTRACT: In order for cooperative robots ("co-robots") to respond to human behaviors accurately and efficiently in human-robot collaboration, interpretation of human actions, awareness of new situations, and appropriate decision making are all crucial abilities for co-robots. For this purpose, the human behaviors should be interpreted by co-robots in the same manner as human peers. To address this issue, a novel interpretability indicator is introduced so that robot actions are appropriate to the current human behaviors. In addition, the complete consideration of all potential situations of a robot's environment is nearly impossible in real-world applications, making it difficult for the co-robot to act appropriately and safely in new scenarios. This is true even when the pretrained model is highly accurate in a known situation. For effective and safe teaming with humans, we introduce a new generalizability indicator that allows a co-robot to self-reflect and reason about when an observation falls outside the co-robot's learned model. Based on topic modeling and two novel indicators, we propose a new Self-reflective Risk-aware Artificial Cognitive (SRAC) model. The co-robots are able to consider action risks and identify new situations so that better decisions can be made. Experiments both using real-world datasets and on physical robots suggest that our SRAC model significantly outperforms the traditional methodology and enables better decision making in response to human activities.
1605.04986
Dennis Wei
Dennis Wei
A Constant-Factor Bi-Criteria Approximation Guarantee for $k$-means++
17 pages, 1 figure
null
null
null
cs.LG cs.CG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper studies the $k$-means++ algorithm for clustering as well as the class of $D^\ell$ sampling algorithms to which $k$-means++ belongs. It is shown that for any constant factor $\beta > 1$, selecting $\beta k$ cluster centers by $D^\ell$ sampling yields a constant-factor approximation to the optimal clustering with $k$ centers, in expectation and without conditions on the dataset. This result extends the previously known $O(\log k)$ guarantee for the case $\beta = 1$ to the constant-factor bi-criteria regime. It also improves upon an existing constant-factor bi-criteria result that holds only with constant probability.
[ { "version": "v1", "created": "Mon, 16 May 2016 23:41:55 GMT" } ]
2016-05-18T00:00:00
[ [ "Wei", "Dennis", "" ] ]
TITLE: A Constant-Factor Bi-Criteria Approximation Guarantee for $k$-means++ ABSTRACT: This paper studies the $k$-means++ algorithm for clustering as well as the class of $D^\ell$ sampling algorithms to which $k$-means++ belongs. It is shown that for any constant factor $\beta > 1$, selecting $\beta k$ cluster centers by $D^\ell$ sampling yields a constant-factor approximation to the optimal clustering with $k$ centers, in expectation and without conditions on the dataset. This result extends the previously known $O(\log k)$ guarantee for the case $\beta = 1$ to the constant-factor bi-criteria regime. It also improves upon an existing constant-factor bi-criteria result that holds only with constant probability.
1605.04996
Zizhao Zhang
Zizhao Zhang, Fuyong Xing, Xiaoshuang Shi, Lin Yang
SemiContour: A Semi-supervised Learning Approach for Contour Detection
Accepted by Computer Vision and Pattern Recognition (CVPR) 2016
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Supervised contour detection methods usually require many labeled training images to obtain satisfactory performance. However, a large set of annotated data might be unavailable or extremely labor intensive. In this paper, we investigate the usage of semi-supervised learning (SSL) to obtain competitive detection accuracy with very limited training data (three labeled images). Specifically, we propose a semi-supervised structured ensemble learning approach for contour detection built on structured random forests (SRF). To allow SRF to be applicable to unlabeled data, we present an effective sparse representation approach to capture inherent structure in image patches by finding a compact and discriminative low-dimensional subspace representation in an unsupervised manner, enabling the incorporation of abundant unlabeled patches with their estimated structured labels to help SRF perform better node splitting. We re-examine the role of sparsity and propose a novel and fast sparse coding algorithm to boost the overall learning efficiency. To the best of our knowledge, this is the first attempt to apply SSL for contour detection. Extensive experiments on the BSDS500 segmentation dataset and the NYU Depth dataset demonstrate the superiority of the proposed method.
[ { "version": "v1", "created": "Tue, 17 May 2016 01:33:20 GMT" } ]
2016-05-18T00:00:00
[ [ "Zhang", "Zizhao", "" ], [ "Xing", "Fuyong", "" ], [ "Shi", "Xiaoshuang", "" ], [ "Yang", "Lin", "" ] ]
TITLE: SemiContour: A Semi-supervised Learning Approach for Contour Detection ABSTRACT: Supervised contour detection methods usually require many labeled training images to obtain satisfactory performance. However, a large set of annotated data might be unavailable or extremely labor intensive. In this paper, we investigate the usage of semi-supervised learning (SSL) to obtain competitive detection accuracy with very limited training data (three labeled images). Specifically, we propose a semi-supervised structured ensemble learning approach for contour detection built on structured random forests (SRF). To allow SRF to be applicable to unlabeled data, we present an effective sparse representation approach to capture inherent structure in image patches by finding a compact and discriminative low-dimensional subspace representation in an unsupervised manner, enabling the incorporation of abundant unlabeled patches with their estimated structured labels to help SRF perform better node splitting. We re-examine the role of sparsity and propose a novel and fast sparse coding algorithm to boost the overall learning efficiency. To the best of our knowledge, this is the first attempt to apply SSL for contour detection. Extensive experiments on the BSDS500 segmentation dataset and the NYU Depth dataset demonstrate the superiority of the proposed method.
1605.05054
Minseok Park
Minseok Park, Hanxiang Li, Junmo Kim
HARRISON: A Benchmark on HAshtag Recommendation for Real-world Images in Social Networks
null
null
null
null
cs.CV cs.IR cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Simple, short, and compact hashtags cover a wide range of information on social networks. Although many works in the field of natural language processing (NLP) have demonstrated the importance of hashtag recommendation, hashtag recommendation for images has barely been studied. In this paper, we introduce the HARRISON dataset, a benchmark on hashtag recommendation for real world images in social networks. The HARRISON dataset is a realistic dataset, composed of 57,383 photos from Instagram and an average of 4.5 associated hashtags for each photo. To evaluate our dataset, we design a baseline framework consisting of visual feature extractor based on convolutional neural network (CNN) and multi-label classifier based on neural network. Based on this framework, two single feature-based models, object-based and scene-based model, and an integrated model of them are evaluated on the HARRISON dataset. Our dataset shows that hashtag recommendation task requires a wide and contextual understanding of the situation conveyed in the image. As far as we know, this work is the first vision-only attempt at hashtag recommendation for real world images in social networks. We expect this benchmark to accelerate the advancement of hashtag recommendation.
[ { "version": "v1", "created": "Tue, 17 May 2016 08:21:07 GMT" } ]
2016-05-18T00:00:00
[ [ "Park", "Minseok", "" ], [ "Li", "Hanxiang", "" ], [ "Kim", "Junmo", "" ] ]
TITLE: HARRISON: A Benchmark on HAshtag Recommendation for Real-world Images in Social Networks ABSTRACT: Simple, short, and compact hashtags cover a wide range of information on social networks. Although many works in the field of natural language processing (NLP) have demonstrated the importance of hashtag recommendation, hashtag recommendation for images has barely been studied. In this paper, we introduce the HARRISON dataset, a benchmark on hashtag recommendation for real world images in social networks. The HARRISON dataset is a realistic dataset, composed of 57,383 photos from Instagram and an average of 4.5 associated hashtags for each photo. To evaluate our dataset, we design a baseline framework consisting of visual feature extractor based on convolutional neural network (CNN) and multi-label classifier based on neural network. Based on this framework, two single feature-based models, object-based and scene-based model, and an integrated model of them are evaluated on the HARRISON dataset. Our dataset shows that hashtag recommendation task requires a wide and contextual understanding of the situation conveyed in the image. As far as we know, this work is the first vision-only attempt at hashtag recommendation for real world images in social networks. We expect this benchmark to accelerate the advancement of hashtag recommendation.
1605.05212
Youngjune Gwon
Youngjune Gwon and William Campbell and Kevin Brady and Douglas Sturim and Miriam Cha and H.T. Kung
Multimodal Sparse Coding for Event Detection
Multimodal Machine Learning Workshop at NIPS 2015
null
null
null
cs.LG cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Unsupervised feature learning methods have proven effective for classification tasks based on a single modality. We present multimodal sparse coding for learning feature representations shared across multiple modalities. The shared representations are applied to multimedia event detection (MED) and evaluated in comparison to unimodal counterparts, as well as other feature learning methods such as GMM supervectors and sparse RBM. We report the cross-validated classification accuracy and mean average precision of the MED system trained on features learned from our unimodal and multimodal settings for a subset of the TRECVID MED 2014 dataset.
[ { "version": "v1", "created": "Tue, 17 May 2016 15:37:19 GMT" } ]
2016-05-18T00:00:00
[ [ "Gwon", "Youngjune", "" ], [ "Campbell", "William", "" ], [ "Brady", "Kevin", "" ], [ "Sturim", "Douglas", "" ], [ "Cha", "Miriam", "" ], [ "Kung", "H. T.", "" ] ]
TITLE: Multimodal Sparse Coding for Event Detection ABSTRACT: Unsupervised feature learning methods have proven effective for classification tasks based on a single modality. We present multimodal sparse coding for learning feature representations shared across multiple modalities. The shared representations are applied to multimedia event detection (MED) and evaluated in comparison to unimodal counterparts, as well as other feature learning methods such as GMM supervectors and sparse RBM. We report the cross-validated classification accuracy and mean average precision of the MED system trained on features learned from our unimodal and multimodal settings for a subset of the TRECVID MED 2014 dataset.
1605.05239
Benjamin Migliori
Benjamin Migliori, Riley Zeller-Townson, Daniel Grady, Daniel Gebhardt
Biologically Inspired Radio Signal Feature Extraction with Sparse Denoising Autoencoders
null
null
null
null
stat.ML cs.LG cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Automatic modulation classification (AMC) is an important task for modern communication systems; however, it is a challenging problem when signal features and precise models for generating each modulation may be unknown. We present a new biologically-inspired AMC method without the need for models or manually specified features --- thus removing the requirement for expert prior knowledge. We accomplish this task using regularized stacked sparse denoising autoencoders (SSDAs). Our method selects efficient classification features directly from raw in-phase/quadrature (I/Q) radio signals in an unsupervised manner. These features are then used to construct higher-complexity abstract features which can be used for automatic modulation classification. We demonstrate this process using a dataset generated with a software defined radio, consisting of random input bits encoded in 100-sample segments of various common digital radio modulations. Our results show correct classification rates of > 99% at 7.5 dB signal-to-noise ratio (SNR) and > 92% at 0 dB SNR in a 6-way classification test. Our experiments demonstrate a dramatically new and broadly applicable mechanism for performing AMC and related tasks without the need for expert-defined or modulation-specific signal information.
[ { "version": "v1", "created": "Tue, 17 May 2016 17:03:02 GMT" } ]
2016-05-18T00:00:00
[ [ "Migliori", "Benjamin", "" ], [ "Zeller-Townson", "Riley", "" ], [ "Grady", "Daniel", "" ], [ "Gebhardt", "Daniel", "" ] ]
TITLE: Biologically Inspired Radio Signal Feature Extraction with Sparse Denoising Autoencoders ABSTRACT: Automatic modulation classification (AMC) is an important task for modern communication systems; however, it is a challenging problem when signal features and precise models for generating each modulation may be unknown. We present a new biologically-inspired AMC method without the need for models or manually specified features --- thus removing the requirement for expert prior knowledge. We accomplish this task using regularized stacked sparse denoising autoencoders (SSDAs). Our method selects efficient classification features directly from raw in-phase/quadrature (I/Q) radio signals in an unsupervised manner. These features are then used to construct higher-complexity abstract features which can be used for automatic modulation classification. We demonstrate this process using a dataset generated with a software defined radio, consisting of random input bits encoded in 100-sample segments of various common digital radio modulations. Our results show correct classification rates of > 99% at 7.5 dB signal-to-noise ratio (SNR) and > 92% at 0 dB SNR in a 6-way classification test. Our experiments demonstrate a dramatically new and broadly applicable mechanism for performing AMC and related tasks without the need for expert-defined or modulation-specific signal information.
1504.08027
Prashanti Manda
Prashanti Manda, Fiona McCarthy, Bindu Nanduri, Hui Wang, Susan M. Bridges
Information-theoretic Interestingness Measures for Cross-Ontology Data Mining
null
null
null
null
cs.AI cs.CE q-bio.QM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Community annotation of biological entities with concepts from multiple bio-ontologies has created large and growing repositories of ontology-based annotation data with embedded implicit relationships among orthogonal ontologies. Development of efficient data mining methods and metrics to mine and assess the quality of the mined relationships has not kept pace with the growth of annotation data. In this study, we present a data mining method that uses ontology-guided generalization to discover relationships across ontologies along with a new interestingness metric based on information theory. We apply our data mining algorithm and interestingness measures to datasets from the Gene Expression Database at the Mouse Genome Informatics as a preliminary proof of concept to mine relationships between developmental stages in the mouse anatomy ontology and Gene Ontology concepts (biological process, molecular function and cellular component). In addition, we present a comparison of our interestingness metric to four existing metrics. Ontology-based annotation datasets provide a valuable resource for discovery of relationships across ontologies. The use of efficient data mining methods and appropriate interestingness metrics enables the identification of high quality relationships.
[ { "version": "v1", "created": "Wed, 29 Apr 2015 21:15:46 GMT" }, { "version": "v2", "created": "Mon, 16 May 2016 08:58:17 GMT" } ]
2016-05-17T00:00:00
[ [ "Manda", "Prashanti", "" ], [ "McCarthy", "Fiona", "" ], [ "Nanduri", "Bindu", "" ], [ "Wang", "Hui", "" ], [ "Bridges", "Susan M.", "" ] ]
TITLE: Information-theoretic Interestingness Measures for Cross-Ontology Data Mining ABSTRACT: Community annotation of biological entities with concepts from multiple bio-ontologies has created large and growing repositories of ontology-based annotation data with embedded implicit relationships among orthogonal ontologies. Development of efficient data mining methods and metrics to mine and assess the quality of the mined relationships has not kept pace with the growth of annotation data. In this study, we present a data mining method that uses ontology-guided generalization to discover relationships across ontologies along with a new interestingness metric based on information theory. We apply our data mining algorithm and interestingness measures to datasets from the Gene Expression Database at the Mouse Genome Informatics as a preliminary proof of concept to mine relationships between developmental stages in the mouse anatomy ontology and Gene Ontology concepts (biological process, molecular function and cellular component). In addition, we present a comparison of our interestingness metric to four existing metrics. Ontology-based annotation datasets provide a valuable resource for discovery of relationships across ontologies. The use of efficient data mining methods and appropriate interestingness metrics enables the identification of high quality relationships.
1512.01752
Sujith Ravi
Sujith Ravi, Qiming Diao
Large Scale Distributed Semi-Supervised Learning Using Streaming Approximation
10 pages
Proceedings of the 19th International Conference on Artificial Intelligence and Statistics (AISTATS), JMLR: W&CP volume 51, pp. 519-528, 2016
null
null
cs.LG cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Traditional graph-based semi-supervised learning (SSL) approaches, even though widely applied, are not suited for massive data and large label scenarios since they scale linearly with the number of edges $|E|$ and distinct labels $m$. To deal with the large label size problem, recent works propose sketch-based methods to approximate the distribution on labels per node thereby achieving a space reduction from $O(m)$ to $O(\log m)$, under certain conditions. In this paper, we present a novel streaming graph-based SSL approximation that captures the sparsity of the label distribution and ensures the algorithm propagates labels accurately, and further reduces the space complexity per node to $O(1)$. We also provide a distributed version of the algorithm that scales well to large data sizes. Experiments on real-world datasets demonstrate that the new method achieves better performance than existing state-of-the-art algorithms with significant reduction in memory footprint. We also study different graph construction mechanisms for natural language applications and propose a robust graph augmentation strategy trained using state-of-the-art unsupervised deep learning architectures that yields further significant quality gains.
[ { "version": "v1", "created": "Sun, 6 Dec 2015 06:58:57 GMT" }, { "version": "v2", "created": "Mon, 16 May 2016 19:40:37 GMT" } ]
2016-05-17T00:00:00
[ [ "Ravi", "Sujith", "" ], [ "Diao", "Qiming", "" ] ]
TITLE: Large Scale Distributed Semi-Supervised Learning Using Streaming Approximation ABSTRACT: Traditional graph-based semi-supervised learning (SSL) approaches, even though widely applied, are not suited for massive data and large label scenarios since they scale linearly with the number of edges $|E|$ and distinct labels $m$. To deal with the large label size problem, recent works propose sketch-based methods to approximate the distribution on labels per node thereby achieving a space reduction from $O(m)$ to $O(\log m)$, under certain conditions. In this paper, we present a novel streaming graph-based SSL approximation that captures the sparsity of the label distribution and ensures the algorithm propagates labels accurately, and further reduces the space complexity per node to $O(1)$. We also provide a distributed version of the algorithm that scales well to large data sizes. Experiments on real-world datasets demonstrate that the new method achieves better performance than existing state-of-the-art algorithms with significant reduction in memory footprint. We also study different graph construction mechanisms for natural language applications and propose a robust graph augmentation strategy trained using state-of-the-art unsupervised deep learning architectures that yields further significant quality gains.
1601.00306
Yasin Yilmaz
Yasin Yilmaz, Alfred Hero
Multimodal Event Detection in Twitter Hashtag Networks
null
null
null
null
stat.AP cs.SI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Event detection in a multimodal Twitter dataset is considered. We treat the hashtags in the dataset as instances with two modes: text and geolocation features. The text feature consists of a bag-of-words representation. The geolocation feature consists of geotags (i.e., geographical coordinates) of the tweets. Fusing the multimodal data we aim to detect, in terms of topic and geolocation, the interesting events and the associated hashtags. To this end, a generative latent variable model is assumed, and a generalized expectation-maximization (EM) algorithm is derived to learn the model parameters. The proposed method is computationally efficient, and lends itself to big datasets. Experimental results on a Twitter dataset from August 2014 show the efficacy of the proposed method.
[ { "version": "v1", "created": "Sun, 3 Jan 2016 15:48:36 GMT" }, { "version": "v2", "created": "Mon, 16 May 2016 01:59:30 GMT" } ]
2016-05-17T00:00:00
[ [ "Yilmaz", "Yasin", "" ], [ "Hero", "Alfred", "" ] ]
TITLE: Multimodal Event Detection in Twitter Hashtag Networks ABSTRACT: Event detection in a multimodal Twitter dataset is considered. We treat the hashtags in the dataset as instances with two modes: text and geolocation features. The text feature consists of a bag-of-words representation. The geolocation feature consists of geotags (i.e., geographical coordinates) of the tweets. Fusing the multimodal data we aim to detect, in terms of topic and geolocation, the interesting events and the associated hashtags. To this end, a generative latent variable model is assumed, and a generalized expectation-maximization (EM) algorithm is derived to learn the model parameters. The proposed method is computationally efficient, and lends itself to big datasets. Experimental results on a Twitter dataset from August 2014 show the efficacy of the proposed method.
1603.09631
Miroslav Vodol\'an
Miroslav Vodol\'an, Filip Jur\v{c}\'i\v{c}ek
Data Collection for Interactive Learning through the Dialog
null
null
null
null
cs.CL cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper presents a dataset collected from natural dialogs which enables to test the ability of dialog systems to learn new facts from user utterances throughout the dialog. This interactive learning will help with one of the most prevailing problems of open domain dialog system, which is the sparsity of facts a dialog system can reason about. The proposed dataset, consisting of 1900 collected dialogs, allows simulation of an interactive gaining of denotations and questions explanations from users which can be used for the interactive learning.
[ { "version": "v1", "created": "Thu, 31 Mar 2016 15:13:51 GMT" }, { "version": "v2", "created": "Sun, 15 May 2016 13:03:26 GMT" } ]
2016-05-17T00:00:00
[ [ "Vodolán", "Miroslav", "" ], [ "Jurčíček", "Filip", "" ] ]
TITLE: Data Collection for Interactive Learning through the Dialog ABSTRACT: This paper presents a dataset collected from natural dialogs which enables to test the ability of dialog systems to learn new facts from user utterances throughout the dialog. This interactive learning will help with one of the most prevailing problems of open domain dialog system, which is the sparsity of facts a dialog system can reason about. The proposed dataset, consisting of 1900 collected dialogs, allows simulation of an interactive gaining of denotations and questions explanations from users which can be used for the interactive learning.
1604.06242
Nomi Vinokurov
Nomi Vinokurov and Daphna Weinshall
Novelty Detection in MultiClass Scenarios with Incomplete Set of Class Labels
10 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We address the problem of novelty detection in multiclass scenarios where some class labels are missing from the training set. Our method is based on the initial assignment of confidence values, which measure the affinity between a new test point and each known class. We first compare the values of the two top elements in this vector of confidence values. In the heart of our method lies the training of an ensemble of classifiers, each trained to discriminate known from novel classes based on some partition of the training data into presumed-known and presumednovel classes. Our final novelty score is derived from the output of this ensemble of classifiers. We evaluated our method on two datasets of images containing a relatively large number of classes - the Caltech-256 and Cifar-100 datasets. We compared our method to 3 alternative methods which represent commonly used approaches, including the one-class SVM, novelty based on k-NN, novelty based on maximal confidence, and the recent KNFST method. The results show a very clear and marked advantage for our method over all alternative methods, in an experimental setup where class labels are missing during training.
[ { "version": "v1", "created": "Thu, 21 Apr 2016 10:18:26 GMT" }, { "version": "v2", "created": "Sun, 15 May 2016 16:44:15 GMT" } ]
2016-05-17T00:00:00
[ [ "Vinokurov", "Nomi", "" ], [ "Weinshall", "Daphna", "" ] ]
TITLE: Novelty Detection in MultiClass Scenarios with Incomplete Set of Class Labels ABSTRACT: We address the problem of novelty detection in multiclass scenarios where some class labels are missing from the training set. Our method is based on the initial assignment of confidence values, which measure the affinity between a new test point and each known class. We first compare the values of the two top elements in this vector of confidence values. In the heart of our method lies the training of an ensemble of classifiers, each trained to discriminate known from novel classes based on some partition of the training data into presumed-known and presumednovel classes. Our final novelty score is derived from the output of this ensemble of classifiers. We evaluated our method on two datasets of images containing a relatively large number of classes - the Caltech-256 and Cifar-100 datasets. We compared our method to 3 alternative methods which represent commonly used approaches, including the one-class SVM, novelty based on k-NN, novelty based on maximal confidence, and the recent KNFST method. The results show a very clear and marked advantage for our method over all alternative methods, in an experimental setup where class labels are missing during training.
1605.04263
Guohui Xiao
Dag Hovland and Davide Lanti and Martin Rezk and Guohui Xiao
OBDA Constraints for Effective Query Answering (Extended Version)
null
null
null
null
cs.DB cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In Ontology Based Data Access (OBDA) users pose SPARQL queries over an ontology that lies on top of relational datasources. These queries are translated on-the-fly into SQL queries by OBDA systems. Standard SPARQL-to-SQL translation techniques in OBDA often produce SQL queries containing redundant joins and unions, even after a number of semantic and structural optimizations. These redundancies are detrimental to the performance of query answering, especially in complex industrial OBDA scenarios with large enterprise databases. To address this issue, we introduce two novel notions of OBDA constraints and show how to exploit them for efficient query answering. We conduct an extensive set of experiments on large datasets using real world data and queries, showing that these techniques strongly improve the performance of query answering up to orders of magnitude.
[ { "version": "v1", "created": "Fri, 13 May 2016 17:29:28 GMT" }, { "version": "v2", "created": "Mon, 16 May 2016 09:21:26 GMT" } ]
2016-05-17T00:00:00
[ [ "Hovland", "Dag", "" ], [ "Lanti", "Davide", "" ], [ "Rezk", "Martin", "" ], [ "Xiao", "Guohui", "" ] ]
TITLE: OBDA Constraints for Effective Query Answering (Extended Version) ABSTRACT: In Ontology Based Data Access (OBDA) users pose SPARQL queries over an ontology that lies on top of relational datasources. These queries are translated on-the-fly into SQL queries by OBDA systems. Standard SPARQL-to-SQL translation techniques in OBDA often produce SQL queries containing redundant joins and unions, even after a number of semantic and structural optimizations. These redundancies are detrimental to the performance of query answering, especially in complex industrial OBDA scenarios with large enterprise databases. To address this issue, we introduce two novel notions of OBDA constraints and show how to exploit them for efficient query answering. We conduct an extensive set of experiments on large datasets using real world data and queries, showing that these techniques strongly improve the performance of query answering up to orders of magnitude.
1605.04465
Avradeep Bhowmik
Avradeep Bhowmik, Joydeep Ghosh
Monotone Retargeting for Unsupervised Rank Aggregation with Object Features
15 pages, 2 figures, 1 table
null
null
null
stat.ML cs.AI cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Learning the true ordering between objects by aggregating a set of expert opinion rank order lists is an important and ubiquitous problem in many applications ranging from social choice theory to natural language processing and search aggregation. We study the problem of unsupervised rank aggregation where no ground truth ordering information in available, neither about the true preference ordering between any set of objects nor about the quality of individual rank lists. Aggregating the often inconsistent and poor quality rank lists in such an unsupervised manner is a highly challenging problem, and standard consensus-based methods are often ill-defined, and difficult to solve. In this manuscript we propose a novel framework to bypass these issues by using object attributes to augment the standard rank aggregation framework. We design algorithms that learn joint models on both rank lists and object features to obtain an aggregated rank ordering that is more accurate and robust, and also helps weed out rank lists of dubious validity. We validate our techniques on synthetic datasets where our algorithm is able to estimate the true rank ordering even when the rank lists are corrupted. Experiments on three real datasets, MQ2008, MQ2008 and OHSUMED, show that using object features can result in significant improvement in performance over existing rank aggregation methods that do not use object information. Furthermore, when at least some of the rank lists are of high quality, our methods are able to effectively exploit their high expertise to output an aggregated rank ordering of great accuracy.
[ { "version": "v1", "created": "Sat, 14 May 2016 20:35:20 GMT" } ]
2016-05-17T00:00:00
[ [ "Bhowmik", "Avradeep", "" ], [ "Ghosh", "Joydeep", "" ] ]
TITLE: Monotone Retargeting for Unsupervised Rank Aggregation with Object Features ABSTRACT: Learning the true ordering between objects by aggregating a set of expert opinion rank order lists is an important and ubiquitous problem in many applications ranging from social choice theory to natural language processing and search aggregation. We study the problem of unsupervised rank aggregation where no ground truth ordering information in available, neither about the true preference ordering between any set of objects nor about the quality of individual rank lists. Aggregating the often inconsistent and poor quality rank lists in such an unsupervised manner is a highly challenging problem, and standard consensus-based methods are often ill-defined, and difficult to solve. In this manuscript we propose a novel framework to bypass these issues by using object attributes to augment the standard rank aggregation framework. We design algorithms that learn joint models on both rank lists and object features to obtain an aggregated rank ordering that is more accurate and robust, and also helps weed out rank lists of dubious validity. We validate our techniques on synthetic datasets where our algorithm is able to estimate the true rank ordering even when the rank lists are corrupted. Experiments on three real datasets, MQ2008, MQ2008 and OHSUMED, show that using object features can result in significant improvement in performance over existing rank aggregation methods that do not use object information. Furthermore, when at least some of the rank lists are of high quality, our methods are able to effectively exploit their high expertise to output an aggregated rank ordering of great accuracy.
1605.04533
Andreea Ioana Sburlea
Andreea Ioana Sburlea, Luis Montesano, Javier Minguez
Advantages of EEG phase patterns for the detection of gait intention in healthy and stroke subjects
18 pages, 5 figures
null
null
null
cs.HC q-bio.NC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
One use of EEG-based brain-computer interfaces (BCIs) in rehabilitation is the detection of movement intention. In this paper we investigate for the first time the instantaneous phase of movement related cortical potential (MRCP) and its application to the detection of gait intention. We demonstrate the utility of MRCP phase in two independent datasets, in which 10 healthy subjects and 9 chronic stroke patients executed a self-initiated gait task in three sessions. Phase features were compared to more conventional amplitude and power features. The neurophysiology analysis showed that phase features have higher signal-to-noise ratio than the other features. Also, BCI detectors of gait intention based on phase, amplitude, and their combination were evaluated under three conditions: session specific calibration, intersession transfer, and intersubject transfer. Results show that the phase based detector is the most accurate for session specific calibration (movement intention was correctly detected in 66.5% of trials in healthy subjects, and in 63.3% in stroke patients). However, in intersession and intersubject transfer, the detector that combines amplitude and phase features is the most accurate one and the only that retains its accuracy (62.5% in healthy subjects and 59% in stroke patients) w.r.t. session specific calibration. Thus, MRCP phase features improve the detection of gait intention and could be used in practice to remove time-consuming BCI recalibration.
[ { "version": "v1", "created": "Sun, 15 May 2016 12:21:33 GMT" } ]
2016-05-17T00:00:00
[ [ "Sburlea", "Andreea Ioana", "" ], [ "Montesano", "Luis", "" ], [ "Minguez", "Javier", "" ] ]
TITLE: Advantages of EEG phase patterns for the detection of gait intention in healthy and stroke subjects ABSTRACT: One use of EEG-based brain-computer interfaces (BCIs) in rehabilitation is the detection of movement intention. In this paper we investigate for the first time the instantaneous phase of movement related cortical potential (MRCP) and its application to the detection of gait intention. We demonstrate the utility of MRCP phase in two independent datasets, in which 10 healthy subjects and 9 chronic stroke patients executed a self-initiated gait task in three sessions. Phase features were compared to more conventional amplitude and power features. The neurophysiology analysis showed that phase features have higher signal-to-noise ratio than the other features. Also, BCI detectors of gait intention based on phase, amplitude, and their combination were evaluated under three conditions: session specific calibration, intersession transfer, and intersubject transfer. Results show that the phase based detector is the most accurate for session specific calibration (movement intention was correctly detected in 66.5% of trials in healthy subjects, and in 63.3% in stroke patients). However, in intersession and intersubject transfer, the detector that combines amplitude and phase features is the most accurate one and the only that retains its accuracy (62.5% in healthy subjects and 59% in stroke patients) w.r.t. session specific calibration. Thus, MRCP phase features improve the detection of gait intention and could be used in practice to remove time-consuming BCI recalibration.
1605.04644
Xingyan Bin
Xingyan Bin, Ying Zhao and Bilong Shen
Abnormal Subspace Sparse PCA for Anomaly Detection and Interpretation
ODDx3, ACM SIGKDD 2015 Workshop
null
null
null
cs.NA
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The main shortage of principle component analysis (PCA) based anomaly detection models is their interpretability. In this paper, our goal is to propose an interpretable PCA-based model for anomaly detection and interpretation. The propose ASPCA model constructs principal components with sparse and orthogonal loading vectors to represent the abnormal subspace, and uses them to interpret detected anomalies. Our experiments on a synthetic dataset and two real world datasets showed that the proposed ASPCA models achieved comparable detection accuracies as the PCA model, and can provide interpretations for individual anomalies.
[ { "version": "v1", "created": "Mon, 16 May 2016 03:55:31 GMT" } ]
2016-05-17T00:00:00
[ [ "Bin", "Xingyan", "" ], [ "Zhao", "Ying", "" ], [ "Shen", "Bilong", "" ] ]
TITLE: Abnormal Subspace Sparse PCA for Anomaly Detection and Interpretation ABSTRACT: The main shortage of principle component analysis (PCA) based anomaly detection models is their interpretability. In this paper, our goal is to propose an interpretable PCA-based model for anomaly detection and interpretation. The propose ASPCA model constructs principal components with sparse and orthogonal loading vectors to represent the abnormal subspace, and uses them to interpret detected anomalies. Our experiments on a synthetic dataset and two real world datasets showed that the proposed ASPCA models achieved comparable detection accuracies as the PCA model, and can provide interpretations for individual anomalies.
1605.04672
Pushpendre Rastogi
Pushpendre Rastogi, Benjamin Van Durme
A Critical Examination of RESCAL for Completion of Knowledge Bases with Transitive Relations
Four and a half page
null
null
null
stat.ML cs.AI cs.DB cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Link prediction in large knowledge graphs has received a lot of attention recently because of its importance for inferring missing relations and for completing and improving noisily extracted knowledge graphs. Over the years a number of machine learning researchers have presented various models for predicting the presence of missing relations in a knowledge base. Although all the previous methods are presented with empirical results that show high performance on select datasets, there is almost no previous work on understanding the connection between properties of a knowledge base and the performance of a model. In this paper we analyze the RESCAL method and prove that it can not encode asymmetric transitive relations in knowledge bases.
[ { "version": "v1", "created": "Mon, 16 May 2016 07:43:28 GMT" } ]
2016-05-17T00:00:00
[ [ "Rastogi", "Pushpendre", "" ], [ "Van Durme", "Benjamin", "" ] ]
TITLE: A Critical Examination of RESCAL for Completion of Knowledge Bases with Transitive Relations ABSTRACT: Link prediction in large knowledge graphs has received a lot of attention recently because of its importance for inferring missing relations and for completing and improving noisily extracted knowledge graphs. Over the years a number of machine learning researchers have presented various models for predicting the presence of missing relations in a knowledge base. Although all the previous methods are presented with empirical results that show high performance on select datasets, there is almost no previous work on understanding the connection between properties of a knowledge base and the performance of a model. In this paper we analyze the RESCAL method and prove that it can not encode asymmetric transitive relations in knowledge bases.
1605.04850
Michael Gygli
Michael Gygli and Yale Song and Liangliang Cao
Video2GIF: Automatic Generation of Animated GIFs from Video
Accepted to CVPR 2016
null
null
null
cs.CV cs.MM
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We introduce the novel problem of automatically generating animated GIFs from video. GIFs are short looping video with no sound, and a perfect combination between image and video that really capture our attention. GIFs tell a story, express emotion, turn events into humorous moments, and are the new wave of photojournalism. We pose the question: Can we automate the entirely manual and elaborate process of GIF creation by leveraging the plethora of user generated GIF content? We propose a Robust Deep RankNet that, given a video, generates a ranked list of its segments according to their suitability as GIF. We train our model to learn what visual content is often selected for GIFs by using over 100K user generated GIFs and their corresponding video sources. We effectively deal with the noisy web data by proposing a novel adaptive Huber loss in the ranking formulation. We show that our approach is robust to outliers and picks up several patterns that are frequently present in popular animated GIFs. On our new large-scale benchmark dataset, we show the advantage of our approach over several state-of-the-art methods.
[ { "version": "v1", "created": "Mon, 16 May 2016 17:44:31 GMT" } ]
2016-05-17T00:00:00
[ [ "Gygli", "Michael", "" ], [ "Song", "Yale", "" ], [ "Cao", "Liangliang", "" ] ]
TITLE: Video2GIF: Automatic Generation of Animated GIFs from Video ABSTRACT: We introduce the novel problem of automatically generating animated GIFs from video. GIFs are short looping video with no sound, and a perfect combination between image and video that really capture our attention. GIFs tell a story, express emotion, turn events into humorous moments, and are the new wave of photojournalism. We pose the question: Can we automate the entirely manual and elaborate process of GIF creation by leveraging the plethora of user generated GIF content? We propose a Robust Deep RankNet that, given a video, generates a ranked list of its segments according to their suitability as GIF. We train our model to learn what visual content is often selected for GIFs by using over 100K user generated GIFs and their corresponding video sources. We effectively deal with the noisy web data by proposing a novel adaptive Huber loss in the ranking formulation. We show that our approach is robust to outliers and picks up several patterns that are frequently present in popular animated GIFs. On our new large-scale benchmark dataset, we show the advantage of our approach over several state-of-the-art methods.
1401.6169
Hossein Soleimani
Hossein Soleimani, David J. Miller
Parsimonious Topic Models with Salient Word Discovery
null
IEEE Transaction on Knowledge and Data Engineering, 27 (2015) 824-837
10.1109/TKDE.2014.2345378
null
cs.LG cs.CL cs.IR stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a parsimonious topic model for text corpora. In related models such as Latent Dirichlet Allocation (LDA), all words are modeled topic-specifically, even though many words occur with similar frequencies across different topics. Our modeling determines salient words for each topic, which have topic-specific probabilities, with the rest explained by a universal shared model. Further, in LDA all topics are in principle present in every document. By contrast our model gives sparse topic representation, determining the (small) subset of relevant topics for each document. We derive a Bayesian Information Criterion (BIC), balancing model complexity and goodness of fit. Here, interestingly, we identify an effective sample size and corresponding penalty specific to each parameter type in our model. We minimize BIC to jointly determine our entire model -- the topic-specific words, document-specific topics, all model parameter values, {\it and} the total number of topics -- in a wholly unsupervised fashion. Results on three text corpora and an image dataset show that our model achieves higher test set likelihood and better agreement with ground-truth class labels, compared to LDA and to a model designed to incorporate sparsity.
[ { "version": "v1", "created": "Wed, 22 Jan 2014 21:47:48 GMT" }, { "version": "v2", "created": "Thu, 11 Sep 2014 20:24:41 GMT" } ]
2016-05-16T00:00:00
[ [ "Soleimani", "Hossein", "" ], [ "Miller", "David J.", "" ] ]
TITLE: Parsimonious Topic Models with Salient Word Discovery ABSTRACT: We propose a parsimonious topic model for text corpora. In related models such as Latent Dirichlet Allocation (LDA), all words are modeled topic-specifically, even though many words occur with similar frequencies across different topics. Our modeling determines salient words for each topic, which have topic-specific probabilities, with the rest explained by a universal shared model. Further, in LDA all topics are in principle present in every document. By contrast our model gives sparse topic representation, determining the (small) subset of relevant topics for each document. We derive a Bayesian Information Criterion (BIC), balancing model complexity and goodness of fit. Here, interestingly, we identify an effective sample size and corresponding penalty specific to each parameter type in our model. We minimize BIC to jointly determine our entire model -- the topic-specific words, document-specific topics, all model parameter values, {\it and} the total number of topics -- in a wholly unsupervised fashion. Results on three text corpora and an image dataset show that our model achieves higher test set likelihood and better agreement with ground-truth class labels, compared to LDA and to a model designed to incorporate sparsity.
1605.02772
Sofia Kleisarchaki
Sofia Kleisarchaki, Sihem Amer-Yahia, Ahlame Douzal-Chouakria, Vassilis Christophides
Querying Temporal Drifts at Multiple Granularities (Technical Report)
null
null
null
null
cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
There exists a large body of work on online drift detection with the goal of dynamically finding and maintaining changes in data streams. In this paper, we adopt a query-based approach to drift detection. Our approach relies on {\em a drift index}, a structure that captures drift at different time granularities and enables flexible {\em drift queries}. We formalize different drift queries that represent real-world scenarios and develop query evaluation algorithms that use different materializations of the drift index as well as strategies for online index maintenance. We describe a thorough study of the performance of our algorithms on real-world and synthetic datasets with varying change rates.
[ { "version": "v1", "created": "Mon, 9 May 2016 20:38:52 GMT" }, { "version": "v2", "created": "Fri, 13 May 2016 08:22:47 GMT" } ]
2016-05-16T00:00:00
[ [ "Kleisarchaki", "Sofia", "" ], [ "Amer-Yahia", "Sihem", "" ], [ "Douzal-Chouakria", "Ahlame", "" ], [ "Christophides", "Vassilis", "" ] ]
TITLE: Querying Temporal Drifts at Multiple Granularities (Technical Report) ABSTRACT: There exists a large body of work on online drift detection with the goal of dynamically finding and maintaining changes in data streams. In this paper, we adopt a query-based approach to drift detection. Our approach relies on {\em a drift index}, a structure that captures drift at different time granularities and enables flexible {\em drift queries}. We formalize different drift queries that represent real-world scenarios and develop query evaluation algorithms that use different materializations of the drift index as well as strategies for online index maintenance. We describe a thorough study of the performance of our algorithms on real-world and synthetic datasets with varying change rates.
1605.02971
J\"orn-Henrik Jacobsen
J\"orn-Henrik Jacobsen, Jan van Gemert, Zhongyu Lou, Arnold W. M. Smeulders
Structured Receptive Fields in CNNs
Reason for update: i) Fix Reference for "Deep roto-translation scattering for object classification" by Oyallon and Mallat. ii) Fixed two minor typos. iii) Removed implicit assumption in equation (4) where scale is represented with diffusion time and adapted to rest of paper where scale is represented with standard deviation, to avoid possible confusion
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Learning powerful feature representations with CNNs is hard when training data are limited. Pre-training is one way to overcome this, but it requires large datasets sufficiently similar to the target domain. Another option is to design priors into the model, which can range from tuned hyperparameters to fully engineered representations like Scattering Networks. We combine these ideas into structured receptive field networks, a model which has a fixed filter basis and yet retains the flexibility of CNNs. This flexibility is achieved by expressing receptive fields in CNNs as a weighted sum over a fixed basis which is similar in spirit to Scattering Networks. The key difference is that we learn arbitrary effective filter sets from the basis rather than modeling the filters. This approach explicitly connects classical multiscale image analysis with general CNNs. With structured receptive field networks, we improve considerably over unstructured CNNs for small and medium dataset scenarios as well as over Scattering for large datasets. We validate our findings on ILSVRC2012, Cifar-10, Cifar-100 and MNIST. As a realistic small dataset example, we show state-of-the-art classification results on popular 3D MRI brain-disease datasets where pre-training is difficult due to a lack of large public datasets in a similar domain.
[ { "version": "v1", "created": "Tue, 10 May 2016 12:18:03 GMT" }, { "version": "v2", "created": "Fri, 13 May 2016 11:56:08 GMT" } ]
2016-05-16T00:00:00
[ [ "Jacobsen", "Jörn-Henrik", "" ], [ "van Gemert", "Jan", "" ], [ "Lou", "Zhongyu", "" ], [ "Smeulders", "Arnold W. M.", "" ] ]
TITLE: Structured Receptive Fields in CNNs ABSTRACT: Learning powerful feature representations with CNNs is hard when training data are limited. Pre-training is one way to overcome this, but it requires large datasets sufficiently similar to the target domain. Another option is to design priors into the model, which can range from tuned hyperparameters to fully engineered representations like Scattering Networks. We combine these ideas into structured receptive field networks, a model which has a fixed filter basis and yet retains the flexibility of CNNs. This flexibility is achieved by expressing receptive fields in CNNs as a weighted sum over a fixed basis which is similar in spirit to Scattering Networks. The key difference is that we learn arbitrary effective filter sets from the basis rather than modeling the filters. This approach explicitly connects classical multiscale image analysis with general CNNs. With structured receptive field networks, we improve considerably over unstructured CNNs for small and medium dataset scenarios as well as over Scattering for large datasets. We validate our findings on ILSVRC2012, Cifar-10, Cifar-100 and MNIST. As a realistic small dataset example, we show state-of-the-art classification results on popular 3D MRI brain-disease datasets where pre-training is difficult due to a lack of large public datasets in a similar domain.
1605.03284
Yuezhang Li
Tian Tian and Yuezhang Li
Machine Comprehension Based on Learning to Rank
9 pages
null
null
null
cs.CL
http://creativecommons.org/licenses/by/4.0/
Machine comprehension plays an essential role in NLP and has been widely explored with dataset like MCTest. However, this dataset is too simple and too small for learning true reasoning abilities. \cite{hermann2015teaching} therefore release a large scale news article dataset and propose a deep LSTM reader system for machine comprehension. However, the training process is expensive. We therefore try feature-engineered approach with semantics on the new dataset to see how traditional machine learning technique and semantics can help with machine comprehension. Meanwhile, our proposed L2R reader system achieves good performance with efficiency and less training data.
[ { "version": "v1", "created": "Wed, 11 May 2016 05:05:05 GMT" }, { "version": "v2", "created": "Fri, 13 May 2016 01:06:09 GMT" } ]
2016-05-16T00:00:00
[ [ "Tian", "Tian", "" ], [ "Li", "Yuezhang", "" ] ]
TITLE: Machine Comprehension Based on Learning to Rank ABSTRACT: Machine comprehension plays an essential role in NLP and has been widely explored with dataset like MCTest. However, this dataset is too simple and too small for learning true reasoning abilities. \cite{hermann2015teaching} therefore release a large scale news article dataset and propose a deep LSTM reader system for machine comprehension. However, the training process is expensive. We therefore try feature-engineered approach with semantics on the new dataset to see how traditional machine learning technique and semantics can help with machine comprehension. Meanwhile, our proposed L2R reader system achieves good performance with efficiency and less training data.
1605.04002
Paul Tupper
Paul Tupper and Bobak Shahriari
Which Learning Algorithms Can Generalize Identity-Based Rules to Novel Inputs?
6 pages, accepted abstract at COGSCI 2016
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We propose a novel framework for the analysis of learning algorithms that allows us to say when such algorithms can and cannot generalize certain patterns from training data to test data. In particular we focus on situations where the rule that must be learned concerns two components of a stimulus being identical. We call such a basis for discrimination an identity-based rule. Identity-based rules have proven to be difficult or impossible for certain types of learning algorithms to acquire from limited datasets. This is in contrast to human behaviour on similar tasks. Here we provide a framework for rigorously establishing which learning algorithms will fail at generalizing identity-based rules to novel stimuli. We use this framework to show that such algorithms are unable to generalize identity-based rules to novel inputs unless trained on virtually all possible inputs. We demonstrate these results computationally with a multilayer feedforward neural network.
[ { "version": "v1", "created": "Thu, 12 May 2016 22:42:48 GMT" } ]
2016-05-16T00:00:00
[ [ "Tupper", "Paul", "" ], [ "Shahriari", "Bobak", "" ] ]
TITLE: Which Learning Algorithms Can Generalize Identity-Based Rules to Novel Inputs? ABSTRACT: We propose a novel framework for the analysis of learning algorithms that allows us to say when such algorithms can and cannot generalize certain patterns from training data to test data. In particular we focus on situations where the rule that must be learned concerns two components of a stimulus being identical. We call such a basis for discrimination an identity-based rule. Identity-based rules have proven to be difficult or impossible for certain types of learning algorithms to acquire from limited datasets. This is in contrast to human behaviour on similar tasks. Here we provide a framework for rigorously establishing which learning algorithms will fail at generalizing identity-based rules to novel stimuli. We use this framework to show that such algorithms are unable to generalize identity-based rules to novel inputs unless trained on virtually all possible inputs. We demonstrate these results computationally with a multilayer feedforward neural network.
1605.04034
Joey Tianyi Zhou Dr
Joey Tianyi Zhou, Xinxing Xu, Sinno Jialin Pan, Ivor W. Tsang, Zheng Qin and Rick Siow Mong Goh
Transfer Hashing with Privileged Information
Accepted by IJCAI-2016
null
null
null
cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Most existing learning to hash methods assume that there are sufficient data, either labeled or unlabeled, on the domain of interest (i.e., the target domain) for training. However, this assumption cannot be satisfied in some real-world applications. To address this data sparsity issue in hashing, inspired by transfer learning, we propose a new framework named Transfer Hashing with Privileged Information (THPI). Specifically, we extend the standard learning to hash method, Iterative Quantization (ITQ), in a transfer learning manner, namely ITQ+. In ITQ+, a new slack function is learned from auxiliary data to approximate the quantization error in ITQ. We developed an alternating optimization approach to solve the resultant optimization problem for ITQ+. We further extend ITQ+ to LapITQ+ by utilizing the geometry structure among the auxiliary data for learning more precise binary codes in the target domain. Extensive experiments on several benchmark datasets verify the effectiveness of our proposed approaches through comparisons with several state-of-the-art baselines.
[ { "version": "v1", "created": "Fri, 13 May 2016 02:49:43 GMT" } ]
2016-05-16T00:00:00
[ [ "Zhou", "Joey Tianyi", "" ], [ "Xu", "Xinxing", "" ], [ "Pan", "Sinno Jialin", "" ], [ "Tsang", "Ivor W.", "" ], [ "Qin", "Zheng", "" ], [ "Goh", "Rick Siow Mong", "" ] ]
TITLE: Transfer Hashing with Privileged Information ABSTRACT: Most existing learning to hash methods assume that there are sufficient data, either labeled or unlabeled, on the domain of interest (i.e., the target domain) for training. However, this assumption cannot be satisfied in some real-world applications. To address this data sparsity issue in hashing, inspired by transfer learning, we propose a new framework named Transfer Hashing with Privileged Information (THPI). Specifically, we extend the standard learning to hash method, Iterative Quantization (ITQ), in a transfer learning manner, namely ITQ+. In ITQ+, a new slack function is learned from auxiliary data to approximate the quantization error in ITQ. We developed an alternating optimization approach to solve the resultant optimization problem for ITQ+. We further extend ITQ+ to LapITQ+ by utilizing the geometry structure among the auxiliary data for learning more precise binary codes in the target domain. Extensive experiments on several benchmark datasets verify the effectiveness of our proposed approaches through comparisons with several state-of-the-art baselines.
1605.04068
Falong Shen
Falong Shen and Gang Zeng
Fast Semantic Image Segmentation with High Order Context and Guided Filtering
14 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper describes a fast and accurate semantic image segmentation approach that encodes not only the discriminative features from deep neural networks, but also the high-order context compatibility among adjacent objects as well as low level image features. We formulate the underlying problem as the conditional random field that embeds local feature extraction, clique potential construction, and guided filtering within the same framework, and provide an efficient coarse-to-fine solver. At the coarse level, we combine local feature representation and context interaction using a deep convolutional network, and directly learn the interaction from high order cliques with a message passing routine, avoiding time-consuming explicit graph inference for joint probability distribution. At the fine level, we introduce a guided filtering interpretation for the mean field algorithm, and achieve accurate object boundaries with 100+ faster than classic learning methods. The two parts are connected and jointly trained in an end-to-end fashion. Experimental results on Pascal VOC 2012 dataset have shown that the proposed algorithm outperforms the state-of-the-art, and that it achieves the rank 1 performance at the time of submission, both of which prove the effectiveness of this unified framework for semantic image segmentation.
[ { "version": "v1", "created": "Fri, 13 May 2016 07:21:37 GMT" } ]
2016-05-16T00:00:00
[ [ "Shen", "Falong", "" ], [ "Zeng", "Gang", "" ] ]
TITLE: Fast Semantic Image Segmentation with High Order Context and Guided Filtering ABSTRACT: This paper describes a fast and accurate semantic image segmentation approach that encodes not only the discriminative features from deep neural networks, but also the high-order context compatibility among adjacent objects as well as low level image features. We formulate the underlying problem as the conditional random field that embeds local feature extraction, clique potential construction, and guided filtering within the same framework, and provide an efficient coarse-to-fine solver. At the coarse level, we combine local feature representation and context interaction using a deep convolutional network, and directly learn the interaction from high order cliques with a message passing routine, avoiding time-consuming explicit graph inference for joint probability distribution. At the fine level, we introduce a guided filtering interpretation for the mean field algorithm, and achieve accurate object boundaries with 100+ faster than classic learning methods. The two parts are connected and jointly trained in an end-to-end fashion. Experimental results on Pascal VOC 2012 dataset have shown that the proposed algorithm outperforms the state-of-the-art, and that it achieves the rank 1 performance at the time of submission, both of which prove the effectiveness of this unified framework for semantic image segmentation.
1605.04192
Symeon Chouvardas
Symeon Chouvardas, Mohammed Amin Abdullah, Lucas Claude, Moez Draief
Robust On-line Matrix Completion on Graphs
null
null
null
null
cs.IT math.IT
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study online robust matrix completion on graphs. At each iteration a vector with some entries missing is revealed and our goal is to reconstruct it by identifying the underlying low-dimensional subspace from which the vectors are drawn. We assume there is an underlying graph structure to the data, that is, the components of each vector correspond to nodes of a certain (known) graph, and their values are related accordingly. We give algorithms that exploit the graph to reconstruct the incomplete data, even in the presence of outlier noise. The theoretical properties of the algorithms are studied and numerical experiments using both synthetic and real world datasets verify the improved performance of the proposed technique compared to other state of the art algorithms.
[ { "version": "v1", "created": "Fri, 13 May 2016 14:29:08 GMT" } ]
2016-05-16T00:00:00
[ [ "Chouvardas", "Symeon", "" ], [ "Abdullah", "Mohammed Amin", "" ], [ "Claude", "Lucas", "" ], [ "Draief", "Moez", "" ] ]
TITLE: Robust On-line Matrix Completion on Graphs ABSTRACT: We study online robust matrix completion on graphs. At each iteration a vector with some entries missing is revealed and our goal is to reconstruct it by identifying the underlying low-dimensional subspace from which the vectors are drawn. We assume there is an underlying graph structure to the data, that is, the components of each vector correspond to nodes of a certain (known) graph, and their values are related accordingly. We give algorithms that exploit the graph to reconstruct the incomplete data, even in the presence of outlier noise. The theoretical properties of the algorithms are studied and numerical experiments using both synthetic and real world datasets verify the improved performance of the proposed technique compared to other state of the art algorithms.
1504.01891
Marios Meimaris
Marios Meimaris, George Papastefanatos, Stratis Viglas, Yannis Stavrakas, Christos Pateritsas and Ioannis Anagnostopoulos
A Query Language for Multi-version Data Web Archives
null
null
null
null
cs.DB
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The Data Web refers to the vast and rapidly increasing quantity of scientific, corporate, government and crowd-sourced data published in the form of Linked Open Data, which encourages the uniform representation of heterogeneous data items on the web and the creation of links between them. The growing availability of open linked datasets has brought forth significant new challenges regarding their proper preservation and the management of evolving information within them. In this paper, we focus on the evolution and preservation challenges related to publishing and preserving evolving linked data across time. We discuss the main problems regarding their proper modelling and querying and provide a conceptual model and a query language for modelling and retrieving evolving data along with changes affecting them. We present in details the syntax of the query language and demonstrate its functionality over a real-world use case of evolving linked dataset from the biological domain.
[ { "version": "v1", "created": "Wed, 8 Apr 2015 09:53:52 GMT" }, { "version": "v2", "created": "Fri, 11 Sep 2015 14:38:17 GMT" }, { "version": "v3", "created": "Thu, 12 May 2016 16:00:10 GMT" } ]
2016-05-13T00:00:00
[ [ "Meimaris", "Marios", "" ], [ "Papastefanatos", "George", "" ], [ "Viglas", "Stratis", "" ], [ "Stavrakas", "Yannis", "" ], [ "Pateritsas", "Christos", "" ], [ "Anagnostopoulos", "Ioannis", "" ] ]
TITLE: A Query Language for Multi-version Data Web Archives ABSTRACT: The Data Web refers to the vast and rapidly increasing quantity of scientific, corporate, government and crowd-sourced data published in the form of Linked Open Data, which encourages the uniform representation of heterogeneous data items on the web and the creation of links between them. The growing availability of open linked datasets has brought forth significant new challenges regarding their proper preservation and the management of evolving information within them. In this paper, we focus on the evolution and preservation challenges related to publishing and preserving evolving linked data across time. We discuss the main problems regarding their proper modelling and querying and provide a conceptual model and a query language for modelling and retrieving evolving data along with changes affecting them. We present in details the syntax of the query language and demonstrate its functionality over a real-world use case of evolving linked dataset from the biological domain.
1602.06541
Martin Thoma
Martin Thoma
A Survey of Semantic Segmentation
Fixed typo in accuracy metrics formula; added value range of accuracy metrics; consistent naming of variables
null
null
null
cs.CV
http://creativecommons.org/licenses/by-sa/4.0/
This survey gives an overview over different techniques used for pixel-level semantic segmentation. Metrics and datasets for the evaluation of segmentation algorithms and traditional approaches for segmentation such as unsupervised methods, Decision Forests and SVMs are described and pointers to the relevant papers are given. Recently published approaches with convolutional neural networks are mentioned and typical problematic situations for segmentation algorithms are examined. A taxonomy of segmentation algorithms is given.
[ { "version": "v1", "created": "Sun, 21 Feb 2016 15:28:04 GMT" }, { "version": "v2", "created": "Wed, 11 May 2016 21:57:48 GMT" } ]
2016-05-13T00:00:00
[ [ "Thoma", "Martin", "" ] ]
TITLE: A Survey of Semantic Segmentation ABSTRACT: This survey gives an overview over different techniques used for pixel-level semantic segmentation. Metrics and datasets for the evaluation of segmentation algorithms and traditional approaches for segmentation such as unsupervised methods, Decision Forests and SVMs are described and pointers to the relevant papers are given. Recently published approaches with convolutional neural networks are mentioned and typical problematic situations for segmentation algorithms are examined. A taxonomy of segmentation algorithms is given.
1605.01539
Szymon Grabowski
Szymon Grabowski, Marcin Raniszewski
Rank and select: Another lesson learned
Compared to v1: slightly optimized rank implementations
null
null
null
cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Rank and select queries on bitmaps are essential building bricks of many compressed data structures, including text indexes, membership and range supporting spatial data structures, compressed graphs, and more. Theoretically considered yet in 1980s, these primitives have also been a subject of vivid research concerning their practical incarnations in the last decade. We present a few novel rank/select variants, focusing mostly on speed, obtaining competitive space-time results in the compressed setting. Our findings can be summarized as follows: $(i)$ no single rank/select solution works best on any kind of data (ours are optimized for concatenated bit arrays obtained from wavelet trees for real text datasets), $(ii)$ it pays to efficiently handle blocks consisting of all 0 or all 1 bits, $(iii)$ compressed select does not have to be significantly slower than compressed rank at a comparable memory use.
[ { "version": "v1", "created": "Thu, 5 May 2016 09:39:59 GMT" }, { "version": "v2", "created": "Thu, 12 May 2016 16:01:30 GMT" } ]
2016-05-13T00:00:00
[ [ "Grabowski", "Szymon", "" ], [ "Raniszewski", "Marcin", "" ] ]
TITLE: Rank and select: Another lesson learned ABSTRACT: Rank and select queries on bitmaps are essential building bricks of many compressed data structures, including text indexes, membership and range supporting spatial data structures, compressed graphs, and more. Theoretically considered yet in 1980s, these primitives have also been a subject of vivid research concerning their practical incarnations in the last decade. We present a few novel rank/select variants, focusing mostly on speed, obtaining competitive space-time results in the compressed setting. Our findings can be summarized as follows: $(i)$ no single rank/select solution works best on any kind of data (ours are optimized for concatenated bit arrays obtained from wavelet trees for real text datasets), $(ii)$ it pays to efficiently handle blocks consisting of all 0 or all 1 bits, $(iii)$ compressed select does not have to be significantly slower than compressed rank at a comparable memory use.
1605.03688
Minghuang Ma
Minghuang Ma, Haoqi Fan, Kris M. Kitani
Going Deeper into First-Person Activity Recognition
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We bring together ideas from recent work on feature design for egocentric action recognition under one framework by exploring the use of deep convolutional neural networks (CNN). Recent work has shown that features such as hand appearance, object attributes, local hand motion and camera ego-motion are important for characterizing first-person actions. To integrate these ideas under one framework, we propose a twin stream network architecture, where one stream analyzes appearance information and the other stream analyzes motion information. Our appearance stream encodes prior knowledge of the egocentric paradigm by explicitly training the network to segment hands and localize objects. By visualizing certain neuron activation of our network, we show that our proposed architecture naturally learns features that capture object attributes and hand-object configurations. Our extensive experiments on benchmark egocentric action datasets show that our deep architecture enables recognition rates that significantly outperform state-of-the-art techniques -- an average $6.6\%$ increase in accuracy over all datasets. Furthermore, by learning to recognize objects, actions and activities jointly, the performance of individual recognition tasks also increase by $30\%$ (actions) and $14\%$ (objects). We also include the results of extensive ablative analysis to highlight the importance of network design decisions..
[ { "version": "v1", "created": "Thu, 12 May 2016 05:59:50 GMT" } ]
2016-05-13T00:00:00
[ [ "Ma", "Minghuang", "" ], [ "Fan", "Haoqi", "" ], [ "Kitani", "Kris M.", "" ] ]
TITLE: Going Deeper into First-Person Activity Recognition ABSTRACT: We bring together ideas from recent work on feature design for egocentric action recognition under one framework by exploring the use of deep convolutional neural networks (CNN). Recent work has shown that features such as hand appearance, object attributes, local hand motion and camera ego-motion are important for characterizing first-person actions. To integrate these ideas under one framework, we propose a twin stream network architecture, where one stream analyzes appearance information and the other stream analyzes motion information. Our appearance stream encodes prior knowledge of the egocentric paradigm by explicitly training the network to segment hands and localize objects. By visualizing certain neuron activation of our network, we show that our proposed architecture naturally learns features that capture object attributes and hand-object configurations. Our extensive experiments on benchmark egocentric action datasets show that our deep architecture enables recognition rates that significantly outperform state-of-the-art techniques -- an average $6.6\%$ increase in accuracy over all datasets. Furthermore, by learning to recognize objects, actions and activities jointly, the performance of individual recognition tasks also increase by $30\%$ (actions) and $14\%$ (objects). We also include the results of extensive ablative analysis to highlight the importance of network design decisions..
1605.03705
Marcus Rohrbach
Anna Rohrbach, Atousa Torabi, Marcus Rohrbach, Niket Tandon, Christopher Pal, Hugo Larochelle, Aaron Courville, Bernt Schiele
Movie Description
null
null
null
null
cs.CV cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Audio Description (AD) provides linguistic descriptions of movies and allows visually impaired people to follow a movie along with their peers. Such descriptions are by design mainly visual and thus naturally form an interesting data source for computer vision and computational linguistics. In this work we propose a novel dataset which contains transcribed ADs, which are temporally aligned to full length movies. In addition we also collected and aligned movie scripts used in prior work and compare the two sources of descriptions. In total the Large Scale Movie Description Challenge (LSMDC) contains a parallel corpus of 118,114 sentences and video clips from 202 movies. First we characterize the dataset by benchmarking different approaches for generating video descriptions. Comparing ADs to scripts, we find that ADs are indeed more visual and describe precisely what is shown rather than what should happen according to the scripts created prior to movie production. Furthermore, we present and compare the results of several teams who participated in a challenge organized in the context of the workshop "Describing and Understanding Video & The Large Scale Movie Description Challenge (LSMDC)", at ICCV 2015.
[ { "version": "v1", "created": "Thu, 12 May 2016 07:34:08 GMT" } ]
2016-05-13T00:00:00
[ [ "Rohrbach", "Anna", "" ], [ "Torabi", "Atousa", "" ], [ "Rohrbach", "Marcus", "" ], [ "Tandon", "Niket", "" ], [ "Pal", "Christopher", "" ], [ "Larochelle", "Hugo", "" ], [ "Courville", "Aaron", "" ], [ "Schiele", "Bernt", "" ] ]
TITLE: Movie Description ABSTRACT: Audio Description (AD) provides linguistic descriptions of movies and allows visually impaired people to follow a movie along with their peers. Such descriptions are by design mainly visual and thus naturally form an interesting data source for computer vision and computational linguistics. In this work we propose a novel dataset which contains transcribed ADs, which are temporally aligned to full length movies. In addition we also collected and aligned movie scripts used in prior work and compare the two sources of descriptions. In total the Large Scale Movie Description Challenge (LSMDC) contains a parallel corpus of 118,114 sentences and video clips from 202 movies. First we characterize the dataset by benchmarking different approaches for generating video descriptions. Comparing ADs to scripts, we find that ADs are indeed more visual and describe precisely what is shown rather than what should happen according to the scripts created prior to movie production. Furthermore, we present and compare the results of several teams who participated in a challenge organized in the context of the workshop "Describing and Understanding Video & The Large Scale Movie Description Challenge (LSMDC)", at ICCV 2015.
1605.03746
Stefano Rosa
Giorgio Toscana, Stefano Rosa
Fast Graph-Based Object Segmentation for RGB-D Images
null
null
null
null
cs.CV cs.RO
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Object segmentation is an important capability for robotic systems, in particular for grasping. We present a graph- based approach for the segmentation of simple objects from RGB-D images. We are interested in segmenting objects with large variety in appearance, from lack of texture to strong textures, for the task of robotic grasping. The algorithm does not rely on image features or machine learning. We propose a modified Canny edge detector for extracting robust edges by using depth information and two simple cost functions for combining color and depth cues. The cost functions are used to build an undirected graph, which is partitioned using the concept of internal and external differences between graph regions. The partitioning is fast with O(NlogN) complexity. We also discuss ways to deal with missing depth information. We test the approach on different publicly available RGB-D object datasets, such as the Rutgers APC RGB-D dataset and the RGB-D Object Dataset, and compare the results with other existing methods.
[ { "version": "v1", "created": "Thu, 12 May 2016 10:29:14 GMT" } ]
2016-05-13T00:00:00
[ [ "Toscana", "Giorgio", "" ], [ "Rosa", "Stefano", "" ] ]
TITLE: Fast Graph-Based Object Segmentation for RGB-D Images ABSTRACT: Object segmentation is an important capability for robotic systems, in particular for grasping. We present a graph- based approach for the segmentation of simple objects from RGB-D images. We are interested in segmenting objects with large variety in appearance, from lack of texture to strong textures, for the task of robotic grasping. The algorithm does not rely on image features or machine learning. We propose a modified Canny edge detector for extracting robust edges by using depth information and two simple cost functions for combining color and depth cues. The cost functions are used to build an undirected graph, which is partitioned using the concept of internal and external differences between graph regions. The partitioning is fast with O(NlogN) complexity. We also discuss ways to deal with missing depth information. We test the approach on different publicly available RGB-D object datasets, such as the Rutgers APC RGB-D dataset and the RGB-D Object Dataset, and compare the results with other existing methods.
1605.03848
Gilles Louppe
Antonio Sutera, Gilles Louppe, V\^an Anh Huynh-Thu, Louis Wehenkel, Pierre Geurts
Context-dependent feature analysis with random forests
Accepted for presentation at UAI 2016
null
null
null
stat.ML cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In many cases, feature selection is often more complicated than identifying a single subset of input variables that would together explain the output. There may be interactions that depend on contextual information, i.e., variables that reveal to be relevant only in some specific circumstances. In this setting, the contribution of this paper is to extend the random forest variable importances framework in order (i) to identify variables whose relevance is context-dependent and (ii) to characterize as precisely as possible the effect of contextual information on these variables. The usage and the relevance of our framework for highlighting context-dependent variables is illustrated on both artificial and real datasets.
[ { "version": "v1", "created": "Thu, 12 May 2016 14:59:42 GMT" } ]
2016-05-13T00:00:00
[ [ "Sutera", "Antonio", "" ], [ "Louppe", "Gilles", "" ], [ "Huynh-Thu", "Vân Anh", "" ], [ "Wehenkel", "Louis", "" ], [ "Geurts", "Pierre", "" ] ]
TITLE: Context-dependent feature analysis with random forests ABSTRACT: In many cases, feature selection is often more complicated than identifying a single subset of input variables that would together explain the output. There may be interactions that depend on contextual information, i.e., variables that reveal to be relevant only in some specific circumstances. In this setting, the contribution of this paper is to extend the random forest variable importances framework in order (i) to identify variables whose relevance is context-dependent and (ii) to characterize as precisely as possible the effect of contextual information on these variables. The usage and the relevance of our framework for highlighting context-dependent variables is illustrated on both artificial and real datasets.
1511.06449
Eunbyung Park
Eunbyung Park, Alexander C. Berg
Learning to decompose for object detection and instance segmentation
ICLR 2016 Workshop
null
null
null
cs.CV cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Although deep convolutional neural networks(CNNs) have achieved remarkable results on object detection and segmentation, pre- and post-processing steps such as region proposals and non-maximum suppression(NMS), have been required. These steps result in high computational complexity and sensitivity to hyperparameters, e.g. thresholds for NMS. In this work, we propose a novel end-to-end trainable deep neural network architecture, which consists of convolutional and recurrent layers, that generates the correct number of object instances and their bounding boxes (or segmentation masks) given an image, using only a single network evaluation without any pre- or post-processing steps. We have tested on detecting digits in multi-digit images synthesized using MNIST, automatically segmenting digits in these images, and detecting cars in the KITTI benchmark dataset. The proposed approach outperforms a strong CNN baseline on the synthesized digits datasets and shows promising results on KITTI car detection.
[ { "version": "v1", "created": "Thu, 19 Nov 2015 23:30:06 GMT" }, { "version": "v2", "created": "Mon, 30 Nov 2015 06:07:28 GMT" }, { "version": "v3", "created": "Wed, 11 May 2016 02:55:29 GMT" } ]
2016-05-12T00:00:00
[ [ "Park", "Eunbyung", "" ], [ "Berg", "Alexander C.", "" ] ]
TITLE: Learning to decompose for object detection and instance segmentation ABSTRACT: Although deep convolutional neural networks(CNNs) have achieved remarkable results on object detection and segmentation, pre- and post-processing steps such as region proposals and non-maximum suppression(NMS), have been required. These steps result in high computational complexity and sensitivity to hyperparameters, e.g. thresholds for NMS. In this work, we propose a novel end-to-end trainable deep neural network architecture, which consists of convolutional and recurrent layers, that generates the correct number of object instances and their bounding boxes (or segmentation masks) given an image, using only a single network evaluation without any pre- or post-processing steps. We have tested on detecting digits in multi-digit images synthesized using MNIST, automatically segmenting digits in these images, and detecting cars in the KITTI benchmark dataset. The proposed approach outperforms a strong CNN baseline on the synthesized digits datasets and shows promising results on KITTI car detection.
1602.08114
Shohreh Shaghaghian Ms
Shohreh Shaghaghian, Mark Coates
Bayesian Inference of Diffusion Networks with Unknown Infection Times
null
null
null
null
cs.SI physics.soc-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The analysis of diffusion processes in real-world propagation scenarios often involves estimating variables that are not directly observed. These hidden variables include parental relationships, the strengths of connections between nodes, and the moments of time that infection occurs. In this paper, we propose a framework in which all three sets of parameters are assumed to be hidden and we develop a Bayesian approach to infer them. After justifying the model assumptions, we evaluate the performance efficiency of our proposed approach through numerical simulations on synthetic datasets and real-world diffusion processes.
[ { "version": "v1", "created": "Thu, 25 Feb 2016 21:12:03 GMT" }, { "version": "v2", "created": "Thu, 17 Mar 2016 03:10:47 GMT" }, { "version": "v3", "created": "Wed, 11 May 2016 18:58:09 GMT" } ]
2016-05-12T00:00:00
[ [ "Shaghaghian", "Shohreh", "" ], [ "Coates", "Mark", "" ] ]
TITLE: Bayesian Inference of Diffusion Networks with Unknown Infection Times ABSTRACT: The analysis of diffusion processes in real-world propagation scenarios often involves estimating variables that are not directly observed. These hidden variables include parental relationships, the strengths of connections between nodes, and the moments of time that infection occurs. In this paper, we propose a framework in which all three sets of parameters are assumed to be hidden and we develop a Bayesian approach to infer them. After justifying the model assumptions, we evaluate the performance efficiency of our proposed approach through numerical simulations on synthetic datasets and real-world diffusion processes.
1603.06995
Zhicheng Cui
Zhicheng Cui and Wenlin Chen and Yixin Chen
Multi-Scale Convolutional Neural Networks for Time Series Classification
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Time series classification (TSC), the problem of predicting class labels of time series, has been around for decades within the community of data mining and machine learning, and found many important applications such as biomedical engineering and clinical prediction. However, it still remains challenging and falls short of classification accuracy and efficiency. Traditional approaches typically involve extracting discriminative features from the original time series using dynamic time warping (DTW) or shapelet transformation, based on which an off-the-shelf classifier can be applied. These methods are ad-hoc and separate the feature extraction part with the classification part, which limits their accuracy performance. Plus, most existing methods fail to take into account the fact that time series often have features at different time scales. To address these problems, we propose a novel end-to-end neural network model, Multi-Scale Convolutional Neural Networks (MCNN), which incorporates feature extraction and classification in a single framework. Leveraging a novel multi-branch layer and learnable convolutional layers, MCNN automatically extracts features at different scales and frequencies, leading to superior feature representation. MCNN is also computationally efficient, as it naturally leverages GPU computing. We conduct comprehensive empirical evaluation with various existing methods on a large number of benchmark datasets, and show that MCNN advances the state-of-the-art by achieving superior accuracy performance than other leading methods.
[ { "version": "v1", "created": "Tue, 22 Mar 2016 21:37:33 GMT" }, { "version": "v2", "created": "Fri, 1 Apr 2016 04:51:24 GMT" }, { "version": "v3", "created": "Wed, 20 Apr 2016 18:58:29 GMT" }, { "version": "v4", "created": "Wed, 11 May 2016 04:48:21 GMT" } ]
2016-05-12T00:00:00
[ [ "Cui", "Zhicheng", "" ], [ "Chen", "Wenlin", "" ], [ "Chen", "Yixin", "" ] ]
TITLE: Multi-Scale Convolutional Neural Networks for Time Series Classification ABSTRACT: Time series classification (TSC), the problem of predicting class labels of time series, has been around for decades within the community of data mining and machine learning, and found many important applications such as biomedical engineering and clinical prediction. However, it still remains challenging and falls short of classification accuracy and efficiency. Traditional approaches typically involve extracting discriminative features from the original time series using dynamic time warping (DTW) or shapelet transformation, based on which an off-the-shelf classifier can be applied. These methods are ad-hoc and separate the feature extraction part with the classification part, which limits their accuracy performance. Plus, most existing methods fail to take into account the fact that time series often have features at different time scales. To address these problems, we propose a novel end-to-end neural network model, Multi-Scale Convolutional Neural Networks (MCNN), which incorporates feature extraction and classification in a single framework. Leveraging a novel multi-branch layer and learnable convolutional layers, MCNN automatically extracts features at different scales and frequencies, leading to superior feature representation. MCNN is also computationally efficient, as it naturally leverages GPU computing. We conduct comprehensive empirical evaluation with various existing methods on a large number of benchmark datasets, and show that MCNN advances the state-of-the-art by achieving superior accuracy performance than other leading methods.
1605.02951
Eszter Bok\'anyi
Eszter Bok\'anyi, D\'aniel Kondor, L\'aszl\'o Dobos, Tam\'as Seb\H{o}k, J\'ozsef St\'eger, Istv\'an Csabai, G\'abor Vattay
Race, Religion and the City: Twitter Word Frequency Patterns Reveal Dominant Demographic Dimensions in the United States
null
null
10.1057/palcomms.2016.10.
null
physics.soc-ph cs.SI
http://creativecommons.org/licenses/by/4.0/
Recently, numerous approaches have emerged in the social sciences to exploit the opportunities made possible by the vast amounts of data generated by online social networks (OSNs). Having access to information about users on such a scale opens up a range of possibilities, all without the limitations associated with often slow and expensive paper-based polls. A question that remains to be satisfactorily addressed, however, is how demography is represented in the OSN content? Here, we study language use in the US using a corpus of text compiled from over half a billion geo-tagged messages from the online microblogging platform Twitter. Our intention is to reveal the most important spatial patterns in language use in an unsupervised manner and relate them to demographics. Our approach is based on Latent Semantic Analysis (LSA) augmented with the Robust Principal Component Analysis (RPCA) methodology. We find spatially correlated patterns that can be interpreted based on the words associated with them. The main language features can be related to slang use, urbanization, travel, religion and ethnicity, the patterns of which are shown to correlate plausibly with traditional census data. Our findings thus validate the concept of demography being represented in OSN language use and show that the traits observed are inherently present in the word frequencies without any previous assumptions about the dataset. Thus, they could form the basis of further research focusing on the evaluation of demographic data estimation from other big data sources, or on the dynamical processes that result in the patterns found here.
[ { "version": "v1", "created": "Tue, 10 May 2016 11:38:43 GMT" }, { "version": "v2", "created": "Wed, 11 May 2016 07:58:12 GMT" } ]
2016-05-12T00:00:00
[ [ "Bokányi", "Eszter", "" ], [ "Kondor", "Dániel", "" ], [ "Dobos", "László", "" ], [ "Sebők", "Tamás", "" ], [ "Stéger", "József", "" ], [ "Csabai", "István", "" ], [ "Vattay", "Gábor", "" ] ]
TITLE: Race, Religion and the City: Twitter Word Frequency Patterns Reveal Dominant Demographic Dimensions in the United States ABSTRACT: Recently, numerous approaches have emerged in the social sciences to exploit the opportunities made possible by the vast amounts of data generated by online social networks (OSNs). Having access to information about users on such a scale opens up a range of possibilities, all without the limitations associated with often slow and expensive paper-based polls. A question that remains to be satisfactorily addressed, however, is how demography is represented in the OSN content? Here, we study language use in the US using a corpus of text compiled from over half a billion geo-tagged messages from the online microblogging platform Twitter. Our intention is to reveal the most important spatial patterns in language use in an unsupervised manner and relate them to demographics. Our approach is based on Latent Semantic Analysis (LSA) augmented with the Robust Principal Component Analysis (RPCA) methodology. We find spatially correlated patterns that can be interpreted based on the words associated with them. The main language features can be related to slang use, urbanization, travel, religion and ethnicity, the patterns of which are shown to correlate plausibly with traditional census data. Our findings thus validate the concept of demography being represented in OSN language use and show that the traits observed are inherently present in the word frequencies without any previous assumptions about the dataset. Thus, they could form the basis of further research focusing on the evaluation of demographic data estimation from other big data sources, or on the dynamical processes that result in the patterns found here.
1605.03222
Alvaro Soto
Anali Alfaro, Domingo Mery, Alvaro Soto
Action Recognition in Video Using Sparse Coding and Relative Features
Accepted to CVPR 2016
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This work presents an approach to category-based action recognition in video using sparse coding techniques. The proposed approach includes two main contributions: i) A new method to handle intra-class variations by decomposing each video into a reduced set of representative atomic action acts or key-sequences, and ii) A new video descriptor, ITRA: Inter-Temporal Relational Act Descriptor, that exploits the power of comparative reasoning to capture relative similarity relations among key-sequences. In terms of the method to obtain key-sequences, we introduce a loss function that, for each video, leads to the identification of a sparse set of representative key-frames capturing both, relevant particularities arising in the input video, as well as relevant generalities arising in the complete class collection. In terms of the method to obtain the ITRA descriptor, we introduce a novel scheme to quantify relative intra and inter-class similarities among local temporal patterns arising in the videos. The resulting ITRA descriptor demonstrates to be highly effective to discriminate among action categories. As a result, the proposed approach reaches remarkable action recognition performance on several popular benchmark datasets, outperforming alternative state-of-the-art techniques by a large margin.
[ { "version": "v1", "created": "Tue, 10 May 2016 21:52:25 GMT" } ]
2016-05-12T00:00:00
[ [ "Alfaro", "Anali", "" ], [ "Mery", "Domingo", "" ], [ "Soto", "Alvaro", "" ] ]
TITLE: Action Recognition in Video Using Sparse Coding and Relative Features ABSTRACT: This work presents an approach to category-based action recognition in video using sparse coding techniques. The proposed approach includes two main contributions: i) A new method to handle intra-class variations by decomposing each video into a reduced set of representative atomic action acts or key-sequences, and ii) A new video descriptor, ITRA: Inter-Temporal Relational Act Descriptor, that exploits the power of comparative reasoning to capture relative similarity relations among key-sequences. In terms of the method to obtain key-sequences, we introduce a loss function that, for each video, leads to the identification of a sparse set of representative key-frames capturing both, relevant particularities arising in the input video, as well as relevant generalities arising in the complete class collection. In terms of the method to obtain the ITRA descriptor, we introduce a novel scheme to quantify relative intra and inter-class similarities among local temporal patterns arising in the videos. The resulting ITRA descriptor demonstrates to be highly effective to discriminate among action categories. As a result, the proposed approach reaches remarkable action recognition performance on several popular benchmark datasets, outperforming alternative state-of-the-art techniques by a large margin.
1605.03328
Magnus Andersson
Alvaro Rodriguez, Hanqing Zhang, Krister Wiklund, Tomas Brodin, Jonatan Klaminder, Patrik Andersson, Magnus Andersson
A robust particle detection algorithm based on symmetry
Manuscript including supplementary materials
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Particle tracking is common in many biophysical, ecological, and micro-fluidic applications. Reliable tracking information is heavily dependent on of the system under study and algorithms that correctly determines particle position between images. However, in a real environmental context with the presence of noise including particular or dissolved matter in water, and low and fluctuating light conditions, many algorithms fail to obtain reliable information. We propose a new algorithm, the Circular Symmetry algorithm (C-Sym), for detecting the position of a circular particle with high accuracy and precision in noisy conditions. The algorithm takes advantage of the spatial symmetry of the particle allowing for subpixel accuracy. We compare the proposed algorithm with four different methods using both synthetic and experimental datasets. The results show that C-Sym is the most accurate and precise algorithm when tracking micro-particles in all tested conditions and it has the potential for use in applications including tracking biota in their environment.
[ { "version": "v1", "created": "Wed, 11 May 2016 08:38:32 GMT" } ]
2016-05-12T00:00:00
[ [ "Rodriguez", "Alvaro", "" ], [ "Zhang", "Hanqing", "" ], [ "Wiklund", "Krister", "" ], [ "Brodin", "Tomas", "" ], [ "Klaminder", "Jonatan", "" ], [ "Andersson", "Patrik", "" ], [ "Andersson", "Magnus", "" ] ]
TITLE: A robust particle detection algorithm based on symmetry ABSTRACT: Particle tracking is common in many biophysical, ecological, and micro-fluidic applications. Reliable tracking information is heavily dependent on of the system under study and algorithms that correctly determines particle position between images. However, in a real environmental context with the presence of noise including particular or dissolved matter in water, and low and fluctuating light conditions, many algorithms fail to obtain reliable information. We propose a new algorithm, the Circular Symmetry algorithm (C-Sym), for detecting the position of a circular particle with high accuracy and precision in noisy conditions. The algorithm takes advantage of the spatial symmetry of the particle allowing for subpixel accuracy. We compare the proposed algorithm with four different methods using both synthetic and experimental datasets. The results show that C-Sym is the most accurate and precise algorithm when tracking micro-particles in all tested conditions and it has the potential for use in applications including tracking biota in their environment.
1506.02640
Joseph Redmon
Joseph Redmon, Santosh Divvala, Ross Girshick, and Ali Farhadi
You Only Look Once: Unified, Real-Time Object Detection
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We present YOLO, a new approach to object detection. Prior work on object detection repurposes classifiers to perform detection. Instead, we frame object detection as a regression problem to spatially separated bounding boxes and associated class probabilities. A single neural network predicts bounding boxes and class probabilities directly from full images in one evaluation. Since the whole detection pipeline is a single network, it can be optimized end-to-end directly on detection performance. Our unified architecture is extremely fast. Our base YOLO model processes images in real-time at 45 frames per second. A smaller version of the network, Fast YOLO, processes an astounding 155 frames per second while still achieving double the mAP of other real-time detectors. Compared to state-of-the-art detection systems, YOLO makes more localization errors but is far less likely to predict false detections where nothing exists. Finally, YOLO learns very general representations of objects. It outperforms all other detection methods, including DPM and R-CNN, by a wide margin when generalizing from natural images to artwork on both the Picasso Dataset and the People-Art Dataset.
[ { "version": "v1", "created": "Mon, 8 Jun 2015 19:52:52 GMT" }, { "version": "v2", "created": "Tue, 9 Jun 2015 07:51:14 GMT" }, { "version": "v3", "created": "Thu, 11 Jun 2015 19:21:47 GMT" }, { "version": "v4", "created": "Thu, 12 Nov 2015 22:53:44 GMT" }, { "version": "v5", "created": "Mon, 9 May 2016 22:22:11 GMT" } ]
2016-05-11T00:00:00
[ [ "Redmon", "Joseph", "" ], [ "Divvala", "Santosh", "" ], [ "Girshick", "Ross", "" ], [ "Farhadi", "Ali", "" ] ]
TITLE: You Only Look Once: Unified, Real-Time Object Detection ABSTRACT: We present YOLO, a new approach to object detection. Prior work on object detection repurposes classifiers to perform detection. Instead, we frame object detection as a regression problem to spatially separated bounding boxes and associated class probabilities. A single neural network predicts bounding boxes and class probabilities directly from full images in one evaluation. Since the whole detection pipeline is a single network, it can be optimized end-to-end directly on detection performance. Our unified architecture is extremely fast. Our base YOLO model processes images in real-time at 45 frames per second. A smaller version of the network, Fast YOLO, processes an astounding 155 frames per second while still achieving double the mAP of other real-time detectors. Compared to state-of-the-art detection systems, YOLO makes more localization errors but is far less likely to predict false detections where nothing exists. Finally, YOLO learns very general representations of objects. It outperforms all other detection methods, including DPM and R-CNN, by a wide margin when generalizing from natural images to artwork on both the Picasso Dataset and the People-Art Dataset.
1602.03926
Igor Barahona Dr
Igor Barahona, Judith Cavazos, and Jian-Bo Yang
Modelling the level of adoption of analytical tools; An implementation of multi-criteria evidential reasoning
Keywords: MCDA methods; evidential reasoning; analytical tools; multiple source data
International Journal of Supply and Operations Management. (2014) Vol.1, Issue 2, pp 129-151
null
null
stat.AP cs.CY stat.OT
http://creativecommons.org/publicdomain/zero/1.0/
In the future, competitive advantages will be given to organisations that can extract valuable information from massive data and make better decisions. In most cases, this data comes from multiple sources. Therefore, the challenge is to aggregate them into a common framework in order to make them meaningful and useful. This paper will first review the most important multi-criteria decision analysis methods (MCDA) existing in current literature. We will offer a novel, practical and consistent methodology based on a type of MCDA, to aggregate data from two different sources into a common framework. Two datasets that are different in nature but related to the same topic are aggregated to a common scale by implementing a set of transformation rules. This allows us to generate appropriate evidence for assessing and finally prioritising the level of adoption of analytical tools in four types of companies. A numerical example is provided to clarify the form for implementing this methodology. A six-step process is offered as a guideline to assist engineers, researchers or practitioners interested in replicating this methodology in any situation where there is a need to aggregate and transform multiple source data.
[ { "version": "v1", "created": "Thu, 11 Feb 2016 23:02:10 GMT" } ]
2016-05-11T00:00:00
[ [ "Barahona", "Igor", "" ], [ "Cavazos", "Judith", "" ], [ "Yang", "Jian-Bo", "" ] ]
TITLE: Modelling the level of adoption of analytical tools; An implementation of multi-criteria evidential reasoning ABSTRACT: In the future, competitive advantages will be given to organisations that can extract valuable information from massive data and make better decisions. In most cases, this data comes from multiple sources. Therefore, the challenge is to aggregate them into a common framework in order to make them meaningful and useful. This paper will first review the most important multi-criteria decision analysis methods (MCDA) existing in current literature. We will offer a novel, practical and consistent methodology based on a type of MCDA, to aggregate data from two different sources into a common framework. Two datasets that are different in nature but related to the same topic are aggregated to a common scale by implementing a set of transformation rules. This allows us to generate appropriate evidence for assessing and finally prioritising the level of adoption of analytical tools in four types of companies. A numerical example is provided to clarify the form for implementing this methodology. A six-step process is offered as a guideline to assist engineers, researchers or practitioners interested in replicating this methodology in any situation where there is a need to aggregate and transform multiple source data.
1605.02892
Marco Bertini
Simone Ercoli, Marco Bertini and Alberto Del Bimbo
Compact Hash Codes for Efficient Visual Descriptors Retrieval in Large Scale Databases
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we present an efficient method for visual descriptors retrieval based on compact hash codes computed using a multiple k-means assignment. The method has been applied to the problem of approximate nearest neighbor (ANN) search of local and global visual content descriptors, and it has been tested on different datasets: three large scale public datasets of up to one billion descriptors (BIGANN) and, supported by recent progress in convolutional neural networks (CNNs), also on the CIFAR-10 and MNIST datasets. Experimental results show that, despite its simplicity, the proposed method obtains a very high performance that makes it superior to more complex state-of-the-art methods.
[ { "version": "v1", "created": "Tue, 10 May 2016 08:53:04 GMT" } ]
2016-05-11T00:00:00
[ [ "Ercoli", "Simone", "" ], [ "Bertini", "Marco", "" ], [ "Del Bimbo", "Alberto", "" ] ]
TITLE: Compact Hash Codes for Efficient Visual Descriptors Retrieval in Large Scale Databases ABSTRACT: In this paper we present an efficient method for visual descriptors retrieval based on compact hash codes computed using a multiple k-means assignment. The method has been applied to the problem of approximate nearest neighbor (ANN) search of local and global visual content descriptors, and it has been tested on different datasets: three large scale public datasets of up to one billion descriptors (BIGANN) and, supported by recent progress in convolutional neural networks (CNNs), also on the CIFAR-10 and MNIST datasets. Experimental results show that, despite its simplicity, the proposed method obtains a very high performance that makes it superior to more complex state-of-the-art methods.
1605.02917
Mohammad Ali Zare Chahooki
Seyed Hamid Reza Mohammadi, Mohammad Ali Zare Chahooki
Web Spam Detection Using Multiple Kernels in Twin Support Vector Machine
null
null
null
null
cs.IR cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Search engines are the most important tools for web data acquisition. Web pages are crawled and indexed by search Engines. Users typically locate useful web pages by querying a search engine. One of the challenges in search engines administration is spam pages which waste search engine resources. These pages by deception of search engine ranking algorithms try to be showed in the first page of results. There are many approaches to web spam pages detection such as measurement of HTML code style similarity, pages linguistic pattern analysis and machine learning algorithm on page content features. One of the famous algorithms has been used in machine learning approach is Support Vector Machine (SVM) classifier. Recently basic structure of SVM has been changed by new extensions to increase robustness and classification accuracy. In this paper we improved accuracy of web spam detection by using two nonlinear kernels into Twin SVM (TSVM) as an improved extension of SVM. The classifier ability to data separation has been increased by using two separated kernels for each class of data. Effectiveness of new proposed method has been experimented with two publicly used spam datasets called UK-2007 and UK-2006. Results show the effectiveness of proposed kernelized version of TSVM in web spam page detection.
[ { "version": "v1", "created": "Tue, 10 May 2016 10:05:40 GMT" } ]
2016-05-11T00:00:00
[ [ "Mohammadi", "Seyed Hamid Reza", "" ], [ "Chahooki", "Mohammad Ali Zare", "" ] ]
TITLE: Web Spam Detection Using Multiple Kernels in Twin Support Vector Machine ABSTRACT: Search engines are the most important tools for web data acquisition. Web pages are crawled and indexed by search Engines. Users typically locate useful web pages by querying a search engine. One of the challenges in search engines administration is spam pages which waste search engine resources. These pages by deception of search engine ranking algorithms try to be showed in the first page of results. There are many approaches to web spam pages detection such as measurement of HTML code style similarity, pages linguistic pattern analysis and machine learning algorithm on page content features. One of the famous algorithms has been used in machine learning approach is Support Vector Machine (SVM) classifier. Recently basic structure of SVM has been changed by new extensions to increase robustness and classification accuracy. In this paper we improved accuracy of web spam detection by using two nonlinear kernels into Twin SVM (TSVM) as an improved extension of SVM. The classifier ability to data separation has been increased by using two separated kernels for each class of data. Effectiveness of new proposed method has been experimented with two publicly used spam datasets called UK-2007 and UK-2006. Results show the effectiveness of proposed kernelized version of TSVM in web spam page detection.
1605.02960
Konrad Hinsen
Konrad Hinsen
Scientific notations for the digital era
null
null
null
null
physics.soc-ph cs.OH physics.comp-ph physics.hist-ph
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Computers have profoundly changed the way scientific research is done. Whereas the importance of computers as research tools is evident to everyone, the impact of the digital revolution on the representation of scientific knowledge is not yet widely recognized. An ever increasing part of today's scientific knowledge is expressed, published, and archived exclusively in the form of software and electronic datasets. In this essay, I compare these digital scientific notations to the the traditional scientific notations that have been used for centuries, showing how the digital notations optimized for computerized processing are often an obstacle to scientific communication and to creative work by human scientists. I analyze the causes and propose guidelines for the design of more human-friendly digital scientific notations.
[ { "version": "v1", "created": "Tue, 10 May 2016 11:56:49 GMT" } ]
2016-05-11T00:00:00
[ [ "Hinsen", "Konrad", "" ] ]
TITLE: Scientific notations for the digital era ABSTRACT: Computers have profoundly changed the way scientific research is done. Whereas the importance of computers as research tools is evident to everyone, the impact of the digital revolution on the representation of scientific knowledge is not yet widely recognized. An ever increasing part of today's scientific knowledge is expressed, published, and archived exclusively in the form of software and electronic datasets. In this essay, I compare these digital scientific notations to the the traditional scientific notations that have been used for centuries, showing how the digital notations optimized for computerized processing are often an obstacle to scientific communication and to creative work by human scientists. I analyze the causes and propose guidelines for the design of more human-friendly digital scientific notations.
1605.02989
Marco Capo MSc
Marco Cap\'o, Aritz P\'erez, Jos\'e Antonio Lozano
An efficient K-means algorithm for Massive Data
38 pages, 10 figures
null
null
null
stat.ML cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Due to the progressive growth of the amount of data available in a wide variety of scientific fields, it has become more difficult to ma- nipulate and analyze such information. Even though datasets have grown in size, the K-means algorithm remains as one of the most popular clustering methods, in spite of its dependency on the initial settings and high computational cost, especially in terms of distance computations. In this work, we propose an efficient approximation to the K-means problem intended for massive data. Our approach recursively partitions the entire dataset into a small number of sub- sets, each of which is characterized by its representative (center of mass) and weight (cardinality), afterwards a weighted version of the K-means algorithm is applied over such local representation, which can drastically reduce the number of distances computed. In addition to some theoretical properties, experimental results indicate that our method outperforms well-known approaches, such as the K-means++ and the minibatch K-means, in terms of the relation between number of distance computations and the quality of the approximation.
[ { "version": "v1", "created": "Tue, 10 May 2016 13:01:37 GMT" } ]
2016-05-11T00:00:00
[ [ "Capó", "Marco", "" ], [ "Pérez", "Aritz", "" ], [ "Lozano", "José Antonio", "" ] ]
TITLE: An efficient K-means algorithm for Massive Data ABSTRACT: Due to the progressive growth of the amount of data available in a wide variety of scientific fields, it has become more difficult to ma- nipulate and analyze such information. Even though datasets have grown in size, the K-means algorithm remains as one of the most popular clustering methods, in spite of its dependency on the initial settings and high computational cost, especially in terms of distance computations. In this work, we propose an efficient approximation to the K-means problem intended for massive data. Our approach recursively partitions the entire dataset into a small number of sub- sets, each of which is characterized by its representative (center of mass) and weight (cardinality), afterwards a weighted version of the K-means algorithm is applied over such local representation, which can drastically reduce the number of distances computed. In addition to some theoretical properties, experimental results indicate that our method outperforms well-known approaches, such as the K-means++ and the minibatch K-means, in terms of the relation between number of distance computations and the quality of the approximation.
1605.03004
Yanjun Qi Dr.
Zeming Lin, Jack Lanchantin, Yanjun Qi
MUST-CNN: A Multilayer Shift-and-Stitch Deep Convolutional Architecture for Sequence-based Protein Structure Prediction
8 pages ; 3 figures ; deep learning based sequence-sequence prediction. in AAAI 2016
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Predicting protein properties such as solvent accessibility and secondary structure from its primary amino acid sequence is an important task in bioinformatics. Recently, a few deep learning models have surpassed the traditional window based multilayer perceptron. Taking inspiration from the image classification domain we propose a deep convolutional neural network architecture, MUST-CNN, to predict protein properties. This architecture uses a novel multilayer shift-and-stitch (MUST) technique to generate fully dense per-position predictions on protein sequences. Our model is significantly simpler than the state-of-the-art, yet achieves better results. By combining MUST and the efficient convolution operation, we can consider far more parameters while retaining very fast prediction speeds. We beat the state-of-the-art performance on two large protein property prediction datasets.
[ { "version": "v1", "created": "Tue, 10 May 2016 13:31:52 GMT" } ]
2016-05-11T00:00:00
[ [ "Lin", "Zeming", "" ], [ "Lanchantin", "Jack", "" ], [ "Qi", "Yanjun", "" ] ]
TITLE: MUST-CNN: A Multilayer Shift-and-Stitch Deep Convolutional Architecture for Sequence-based Protein Structure Prediction ABSTRACT: Predicting protein properties such as solvent accessibility and secondary structure from its primary amino acid sequence is an important task in bioinformatics. Recently, a few deep learning models have surpassed the traditional window based multilayer perceptron. Taking inspiration from the image classification domain we propose a deep convolutional neural network architecture, MUST-CNN, to predict protein properties. This architecture uses a novel multilayer shift-and-stitch (MUST) technique to generate fully dense per-position predictions on protein sequences. Our model is significantly simpler than the state-of-the-art, yet achieves better results. By combining MUST and the efficient convolution operation, we can consider far more parameters while retaining very fast prediction speeds. We beat the state-of-the-art performance on two large protein property prediction datasets.
1605.03150
Yasamin Alkhorshid
Yasamin Alkhorshid, Kamelia Aryafar, Sven Bauer, and Gerd Wanielik
Road Detection through Supervised Classification
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Autonomous driving is a rapidly evolving technology. Autonomous vehicles are capable of sensing their environment and navigating without human input through sensory information such as radar, lidar, GNSS, vehicle odometry, and computer vision. This sensory input provides a rich dataset that can be used in combination with machine learning models to tackle multiple problems in supervised settings. In this paper we focus on road detection through gray-scale images as the sole sensory input. Our contributions are twofold: first, we introduce an annotated dataset of urban roads for machine learning tasks; second, we introduce a road detection framework on this dataset through supervised classification and hand-crafted feature vectors.
[ { "version": "v1", "created": "Tue, 10 May 2016 18:53:09 GMT" } ]
2016-05-11T00:00:00
[ [ "Alkhorshid", "Yasamin", "" ], [ "Aryafar", "Kamelia", "" ], [ "Bauer", "Sven", "" ], [ "Wanielik", "Gerd", "" ] ]
TITLE: Road Detection through Supervised Classification ABSTRACT: Autonomous driving is a rapidly evolving technology. Autonomous vehicles are capable of sensing their environment and navigating without human input through sensory information such as radar, lidar, GNSS, vehicle odometry, and computer vision. This sensory input provides a rich dataset that can be used in combination with machine learning models to tackle multiple problems in supervised settings. In this paper we focus on road detection through gray-scale images as the sole sensory input. Our contributions are twofold: first, we introduce an annotated dataset of urban roads for machine learning tasks; second, we introduce a road detection framework on this dataset through supervised classification and hand-crafted feature vectors.
1310.1177
Weixiang Shao
Weixiang Shao (1), Xiaoxiao Shi (1) and Philip S. Yu (1) ((1) University of Illinois at Chicago)
Clustering on Multiple Incomplete Datasets via Collective Kernel Learning
ICDM 2013, Code available at https://github.com/software-shao/Collective-Kernel-Learning
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multiple datasets containing different types of features may be available for a given task. For instance, users' profiles can be used to group users for recommendation systems. In addition, a model can also use users' historical behaviors and credit history to group users. Each dataset contains different information and suffices for learning. A number of clustering algorithms on multiple datasets were proposed during the past few years. These algorithms assume that at least one dataset is complete. So far as we know, all the previous methods will not be applicable if there is no complete dataset available. However, in reality, there are many situations where no dataset is complete. As in building a recommendation system, some new users may not have a profile or historical behaviors, while some may not have a credit history. Hence, no available dataset is complete. In order to solve this problem, we propose an approach called Collective Kernel Learning to infer hidden sample similarity from multiple incomplete datasets. The idea is to collectively completes the kernel matrices of incomplete datasets by optimizing the alignment of the shared instances of the datasets. Furthermore, a clustering algorithm is proposed based on the kernel matrix. The experiments on both synthetic and real datasets demonstrate the effectiveness of the proposed approach. The proposed clustering algorithm outperforms the comparison algorithms by as much as two times in normalized mutual information.
[ { "version": "v1", "created": "Fri, 4 Oct 2013 06:18:59 GMT" }, { "version": "v2", "created": "Fri, 6 May 2016 23:35:13 GMT" } ]
2016-05-10T00:00:00
[ [ "Shao", "Weixiang", "" ], [ "Shi", "Xiaoxiao", "" ], [ "Yu", "Philip S.", "" ] ]
TITLE: Clustering on Multiple Incomplete Datasets via Collective Kernel Learning ABSTRACT: Multiple datasets containing different types of features may be available for a given task. For instance, users' profiles can be used to group users for recommendation systems. In addition, a model can also use users' historical behaviors and credit history to group users. Each dataset contains different information and suffices for learning. A number of clustering algorithms on multiple datasets were proposed during the past few years. These algorithms assume that at least one dataset is complete. So far as we know, all the previous methods will not be applicable if there is no complete dataset available. However, in reality, there are many situations where no dataset is complete. As in building a recommendation system, some new users may not have a profile or historical behaviors, while some may not have a credit history. Hence, no available dataset is complete. In order to solve this problem, we propose an approach called Collective Kernel Learning to infer hidden sample similarity from multiple incomplete datasets. The idea is to collectively completes the kernel matrices of incomplete datasets by optimizing the alignment of the shared instances of the datasets. Furthermore, a clustering algorithm is proposed based on the kernel matrix. The experiments on both synthetic and real datasets demonstrate the effectiveness of the proposed approach. The proposed clustering algorithm outperforms the comparison algorithms by as much as two times in normalized mutual information.
1412.6574
Ali Sharif Razavian
Ali Sharif Razavian, Josephine Sullivan, Stefan Carlsson, Atsuto Maki
Visual Instance Retrieval with Deep Convolutional Networks
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper provides an extensive study on the availability of image representations based on convolutional networks (ConvNets) for the task of visual instance retrieval. Besides the choice of convolutional layers, we present an efficient pipeline exploiting multi-scale schemes to extract local features, in particular, by taking geometric invariance into explicit account, i.e. positions, scales and spatial consistency. In our experiments using five standard image retrieval datasets, we demonstrate that generic ConvNet image representations can outperform other state-of-the-art methods if they are extracted appropriately.
[ { "version": "v1", "created": "Sat, 20 Dec 2014 01:32:43 GMT" }, { "version": "v2", "created": "Tue, 13 Jan 2015 19:09:15 GMT" }, { "version": "v3", "created": "Fri, 10 Apr 2015 18:20:51 GMT" }, { "version": "v4", "created": "Mon, 9 May 2016 08:54:31 GMT" } ]
2016-05-10T00:00:00
[ [ "Razavian", "Ali Sharif", "" ], [ "Sullivan", "Josephine", "" ], [ "Carlsson", "Stefan", "" ], [ "Maki", "Atsuto", "" ] ]
TITLE: Visual Instance Retrieval with Deep Convolutional Networks ABSTRACT: This paper provides an extensive study on the availability of image representations based on convolutional networks (ConvNets) for the task of visual instance retrieval. Besides the choice of convolutional layers, we present an efficient pipeline exploiting multi-scale schemes to extract local features, in particular, by taking geometric invariance into explicit account, i.e. positions, scales and spatial consistency. In our experiments using five standard image retrieval datasets, we demonstrate that generic ConvNet image representations can outperform other state-of-the-art methods if they are extracted appropriately.
1604.04558
Jyothi Korra
Jinju Joby and Jyothi Korra
Accessing accurate documents by mining auxiliary document information
null
null
null
null
cs.IR cs.AI cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Earlier techniques of text mining included algorithms like k-means, Naive Bayes, SVM which classify and cluster the text document for mining relevant information about the documents. The need for improving the mining techniques has us searching for techniques using the available algorithms. This paper proposes one technique which uses the auxiliary information that is present inside the text documents to improve the mining. This auxiliary information can be a description to the content. This information can be either useful or completely useless for mining. The user should assess the worth of the auxiliary information before considering this technique for text mining. In this paper, a combination of classical clustering algorithms is used to mine the datasets. The algorithm runs in two stages which carry out mining at different levels of abstraction. The clustered documents would then be classified based on the necessary groups. The proposed technique is aimed at improved results of document clustering.
[ { "version": "v1", "created": "Fri, 15 Apr 2016 16:27:38 GMT" } ]
2016-05-10T00:00:00
[ [ "Joby", "Jinju", "" ], [ "Korra", "Jyothi", "" ] ]
TITLE: Accessing accurate documents by mining auxiliary document information ABSTRACT: Earlier techniques of text mining included algorithms like k-means, Naive Bayes, SVM which classify and cluster the text document for mining relevant information about the documents. The need for improving the mining techniques has us searching for techniques using the available algorithms. This paper proposes one technique which uses the auxiliary information that is present inside the text documents to improve the mining. This auxiliary information can be a description to the content. This information can be either useful or completely useless for mining. The user should assess the worth of the auxiliary information before considering this technique for text mining. In this paper, a combination of classical clustering algorithms is used to mine the datasets. The algorithm runs in two stages which carry out mining at different levels of abstraction. The clustered documents would then be classified based on the necessary groups. The proposed technique is aimed at improved results of document clustering.
1604.06246
Mike Thelwall
Mike Thelwall
Are there too many uncited articles? Zero inflated variants of the discretised lognormal and hooked power law distributions
Thelwall, M. (in press) Journal of Informetrics. Software and data available here: https://dx.doi.org/10.6084/m9.figshare.3186997.v1
Journal of Informetrics 10 (2016), pp. 622-633
10.1016/j.joi.2016.04.014
null
cs.DL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Although statistical models fit many citation data sets reasonably well with the best fitting models being the hooked power law and discretised lognormal distribution, the fits are rarely close. One possible reason is that there might be more uncited articles than would be predicted by any model if some articles are inherently uncitable. Using data from 23 different Scopus categories, this article tests the assumption that removing a proportion of uncited articles from a citation dataset allows statistical distributions to have much closer fits. It also introduces two new models, zero inflated discretised lognormal distribution and the zero inflated hooked power law distribution and algorithms to fit them. In all 23 cases, the zero inflated version of the discretised lognormal distribution was an improvement on the standard version and in 15 out of 23 cases the zero inflated version of the hooked power law was an improvement on the standard version. Without zero inflation the discretised lognormal models fit the data better than the hooked power law distribution 6 out of 23 times and with it, the discretised lognormal models fit the data better than the hooked power law distribution 9 out of 23 times. Apparently uncitable articles seem to occur due to the presence of academic-related magazines in Scopus categories. In conclusion, future citation analysis and research indicators should take into account uncitable articles, and the best fitting distribution for sets of citation counts from a single subject and year is either the zero inflated discretised lognormal or zero inflated hooked power law.
[ { "version": "v1", "created": "Thu, 21 Apr 2016 10:29:28 GMT" } ]
2016-05-10T00:00:00
[ [ "Thelwall", "Mike", "" ] ]
TITLE: Are there too many uncited articles? Zero inflated variants of the discretised lognormal and hooked power law distributions ABSTRACT: Although statistical models fit many citation data sets reasonably well with the best fitting models being the hooked power law and discretised lognormal distribution, the fits are rarely close. One possible reason is that there might be more uncited articles than would be predicted by any model if some articles are inherently uncitable. Using data from 23 different Scopus categories, this article tests the assumption that removing a proportion of uncited articles from a citation dataset allows statistical distributions to have much closer fits. It also introduces two new models, zero inflated discretised lognormal distribution and the zero inflated hooked power law distribution and algorithms to fit them. In all 23 cases, the zero inflated version of the discretised lognormal distribution was an improvement on the standard version and in 15 out of 23 cases the zero inflated version of the hooked power law was an improvement on the standard version. Without zero inflation the discretised lognormal models fit the data better than the hooked power law distribution 6 out of 23 times and with it, the discretised lognormal models fit the data better than the hooked power law distribution 9 out of 23 times. Apparently uncitable articles seem to occur due to the presence of academic-related magazines in Scopus categories. In conclusion, future citation analysis and research indicators should take into account uncitable articles, and the best fitting distribution for sets of citation counts from a single subject and year is either the zero inflated discretised lognormal or zero inflated hooked power law.
1605.02150
Elaheh ShafieiBavani
Elaheh ShafieiBavani, Mohammad Ebrahimi, Raymond Wong, Fang Chen
On Improving Informativity and Grammaticality for Multi-Sentence Compression
19 pages
null
null
UNSW-CSE-TR-201517
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Multi Sentence Compression (MSC) is of great value to many real world applications, such as guided microblog summarization, opinion summarization and newswire summarization. Recently, word graph-based approaches have been proposed and become popular in MSC. Their key assumption is that redundancy among a set of related sentences provides a reliable way to generate informative and grammatical sentences. In this paper, we propose an effective approach to enhance the word graph-based MSC and tackle the issue that most of the state-of-the-art MSC approaches are confronted with: i.e., improving both informativity and grammaticality at the same time. Our approach consists of three main components: (1) a merging method based on Multiword Expressions (MWE); (2) a mapping strategy based on synonymy between words; (3) a re-ranking step to identify the best compression candidates generated using a POS-based language model (POS-LM). We demonstrate the effectiveness of this novel approach using a dataset made of clusters of English newswire sentences. The observed improvements on informativity and grammaticality of the generated compressions show that our approach is superior to state-of-the-art MSC methods.
[ { "version": "v1", "created": "Sat, 7 May 2016 06:39:57 GMT" } ]
2016-05-10T00:00:00
[ [ "ShafieiBavani", "Elaheh", "" ], [ "Ebrahimi", "Mohammad", "" ], [ "Wong", "Raymond", "" ], [ "Chen", "Fang", "" ] ]
TITLE: On Improving Informativity and Grammaticality for Multi-Sentence Compression ABSTRACT: Multi Sentence Compression (MSC) is of great value to many real world applications, such as guided microblog summarization, opinion summarization and newswire summarization. Recently, word graph-based approaches have been proposed and become popular in MSC. Their key assumption is that redundancy among a set of related sentences provides a reliable way to generate informative and grammatical sentences. In this paper, we propose an effective approach to enhance the word graph-based MSC and tackle the issue that most of the state-of-the-art MSC approaches are confronted with: i.e., improving both informativity and grammaticality at the same time. Our approach consists of three main components: (1) a merging method based on Multiword Expressions (MWE); (2) a mapping strategy based on synonymy between words; (3) a re-ranking step to identify the best compression candidates generated using a POS-based language model (POS-LM). We demonstrate the effectiveness of this novel approach using a dataset made of clusters of English newswire sentences. The observed improvements on informativity and grammaticality of the generated compressions show that our approach is superior to state-of-the-art MSC methods.
1605.02216
Sixin Zhang Sixin Zhang
Sixin Zhang
Distributed stochastic optimization for deep learning (thesis)
This is the author's thesis at under supervision of Yann LeCun. Part of the results are based on the paper arXiv:1412.6651 in collaboration with Anna Choromanska and Yann LeCun
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We study the problem of how to distribute the training of large-scale deep learning models in the parallel computing environment. We propose a new distributed stochastic optimization method called Elastic Averaging SGD (EASGD). We analyze the convergence rate of the EASGD method in the synchronous scenario and compare its stability condition with the existing ADMM method in the round-robin scheme. An asynchronous and momentum variant of the EASGD method is applied to train deep convolutional neural networks for image classification on the CIFAR and ImageNet datasets. Our approach accelerates the training and furthermore achieves better test accuracy. It also requires a much smaller amount of communication than other common baseline approaches such as the DOWNPOUR method. We then investigate the limit in speedup of the initial and the asymptotic phase of the mini-batch SGD, the momentum SGD, and the EASGD methods. We find that the spread of the input data distribution has a big impact on their initial convergence rate and stability region. We also find a surprising connection between the momentum SGD and the EASGD method with a negative moving average rate. A non-convex case is also studied to understand when EASGD can get trapped by a saddle point. Finally, we scale up the EASGD method by using a tree structured network topology. We show empirically its advantage and challenge. We also establish a connection between the EASGD and the DOWNPOUR method with the classical Jacobi and the Gauss-Seidel method, thus unifying a class of distributed stochastic optimization methods.
[ { "version": "v1", "created": "Sat, 7 May 2016 16:55:22 GMT" } ]
2016-05-10T00:00:00
[ [ "Zhang", "Sixin", "" ] ]
TITLE: Distributed stochastic optimization for deep learning (thesis) ABSTRACT: We study the problem of how to distribute the training of large-scale deep learning models in the parallel computing environment. We propose a new distributed stochastic optimization method called Elastic Averaging SGD (EASGD). We analyze the convergence rate of the EASGD method in the synchronous scenario and compare its stability condition with the existing ADMM method in the round-robin scheme. An asynchronous and momentum variant of the EASGD method is applied to train deep convolutional neural networks for image classification on the CIFAR and ImageNet datasets. Our approach accelerates the training and furthermore achieves better test accuracy. It also requires a much smaller amount of communication than other common baseline approaches such as the DOWNPOUR method. We then investigate the limit in speedup of the initial and the asymptotic phase of the mini-batch SGD, the momentum SGD, and the EASGD methods. We find that the spread of the input data distribution has a big impact on their initial convergence rate and stability region. We also find a surprising connection between the momentum SGD and the EASGD method with a negative moving average rate. A non-convex case is also studied to understand when EASGD can get trapped by a saddle point. Finally, we scale up the EASGD method by using a tree structured network topology. We show empirically its advantage and challenge. We also establish a connection between the EASGD and the DOWNPOUR method with the classical Jacobi and the Gauss-Seidel method, thus unifying a class of distributed stochastic optimization methods.
1605.02240
Anish Acharya
Anish Acharya, Uddipan Mukherjee, Charless Fowlkes
On Image segmentation using Fractional Gradients-Learning Model Parameters using Approximate Marginal Inference
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Estimates of image gradients play a ubiquitous role in image segmentation and classification problems since gradients directly relate to the boundaries or the edges of a scene. This paper proposes an unified approach to gradient estimation based on fractional calculus that is computationally cheap and readily applicable to any existing algorithm that relies on image gradients. We show experiments on edge detection and image segmentation on the Stanford Backgrounds Dataset where these improved local gradients outperforms state of the art, achieving a performance of 79.2% average accuracy.
[ { "version": "v1", "created": "Sat, 7 May 2016 20:12:12 GMT" } ]
2016-05-10T00:00:00
[ [ "Acharya", "Anish", "" ], [ "Mukherjee", "Uddipan", "" ], [ "Fowlkes", "Charless", "" ] ]
TITLE: On Image segmentation using Fractional Gradients-Learning Model Parameters using Approximate Marginal Inference ABSTRACT: Estimates of image gradients play a ubiquitous role in image segmentation and classification problems since gradients directly relate to the boundaries or the edges of a scene. This paper proposes an unified approach to gradient estimation based on fractional calculus that is computationally cheap and readily applicable to any existing algorithm that relies on image gradients. We show experiments on edge detection and image segmentation on the Stanford Backgrounds Dataset where these improved local gradients outperforms state of the art, achieving a performance of 79.2% average accuracy.
1605.02260
Saihui Hou
Saihui Hou, Zilei Wang, Feng Wu
Deeply Exploit Depth Information for Object Detection
9 pages, 3 figures, and 4 tables. Accepted by CVPR2016 Workshops
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper addresses the issue on how to more effectively coordinate the depth with RGB aiming at boosting the performance of RGB-D object detection. Particularly, we investigate two primary ideas under the CNN model: property derivation and property fusion. Firstly, we propose that the depth can be utilized not only as a type of extra information besides RGB but also to derive more visual properties for comprehensively describing the objects of interest. So a two-stage learning framework consisting of property derivation and fusion is constructed. Here the properties can be derived either from the provided color/depth or their pairs (e.g. the geometry contour adopted in this paper). Secondly, we explore the fusion method of different properties in feature learning, which is boiled down to, under the CNN model, from which layer the properties should be fused together. The analysis shows that different semantic properties should be learned separately and combined before passing into the final classifier. Actually, such a detection way is in accordance with the mechanism of the primary neural cortex (V1) in brain. We experimentally evaluate the proposed method on the challenging dataset, and have achieved state-of-the-art performance.
[ { "version": "v1", "created": "Sun, 8 May 2016 01:56:50 GMT" } ]
2016-05-10T00:00:00
[ [ "Hou", "Saihui", "" ], [ "Wang", "Zilei", "" ], [ "Wu", "Feng", "" ] ]
TITLE: Deeply Exploit Depth Information for Object Detection ABSTRACT: This paper addresses the issue on how to more effectively coordinate the depth with RGB aiming at boosting the performance of RGB-D object detection. Particularly, we investigate two primary ideas under the CNN model: property derivation and property fusion. Firstly, we propose that the depth can be utilized not only as a type of extra information besides RGB but also to derive more visual properties for comprehensively describing the objects of interest. So a two-stage learning framework consisting of property derivation and fusion is constructed. Here the properties can be derived either from the provided color/depth or their pairs (e.g. the geometry contour adopted in this paper). Secondly, we explore the fusion method of different properties in feature learning, which is boiled down to, under the CNN model, from which layer the properties should be fused together. The analysis shows that different semantic properties should be learned separately and combined before passing into the final classifier. Actually, such a detection way is in accordance with the mechanism of the primary neural cortex (V1) in brain. We experimentally evaluate the proposed method on the challenging dataset, and have achieved state-of-the-art performance.
1605.02289
Zhun Zhong
Zhun Zhong, Songzhi Su, Donglin Cao, Shaozi Li
Detecting Ground Control Points via Convolutional Neural Network for Stereo Matching
9 pages
null
null
null
cs.CV
http://creativecommons.org/licenses/by/4.0/
In this paper, we present a novel approach to detect ground control points (GCPs) for stereo matching problem. First of all, we train a convolutional neural network (CNN) on a large stereo set, and compute the matching confidence of each pixel by using the trained CNN model. Secondly, we present a ground control points selection scheme according to the maximum matching confidence of each pixel. Finally, the selected GCPs are used to refine the matching costs, and we apply the new matching costs to perform optimization with semi-global matching algorithm for improving the final disparity maps. We evaluate our approach on the KITTI 2012 stereo benchmark dataset. Our experiments show that the proposed approach significantly improves the accuracy of disparity maps.
[ { "version": "v1", "created": "Sun, 8 May 2016 07:38:40 GMT" } ]
2016-05-10T00:00:00
[ [ "Zhong", "Zhun", "" ], [ "Su", "Songzhi", "" ], [ "Cao", "Donglin", "" ], [ "Li", "Shaozi", "" ] ]
TITLE: Detecting Ground Control Points via Convolutional Neural Network for Stereo Matching ABSTRACT: In this paper, we present a novel approach to detect ground control points (GCPs) for stereo matching problem. First of all, we train a convolutional neural network (CNN) on a large stereo set, and compute the matching confidence of each pixel by using the trained CNN model. Secondly, we present a ground control points selection scheme according to the maximum matching confidence of each pixel. Finally, the selected GCPs are used to refine the matching costs, and we apply the new matching costs to perform optimization with semi-global matching algorithm for improving the final disparity maps. We evaluate our approach on the KITTI 2012 stereo benchmark dataset. Our experiments show that the proposed approach significantly improves the accuracy of disparity maps.
1605.02464
Liqian Ma
Liqian Ma, Hong Liu, Liang Hu, Can Wang, Qianru Sun
Orientation Driven Bag of Appearances for Person Re-identification
13 pages, 15 figures, 3 tables, submitted to IEEE Transactions on Circuits and Systems for Video Technology
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Person re-identification (re-id) consists of associating individual across camera network, which is valuable for intelligent video surveillance and has drawn wide attention. Although person re-identification research is making progress, it still faces some challenges such as varying poses, illumination and viewpoints. For feature representation in re-identification, existing works usually use low-level descriptors which do not take full advantage of body structure information, resulting in low representation ability. %discrimination. To solve this problem, this paper proposes the mid-level body-structure based feature representation (BSFR) which introduces body structure pyramid for codebook learning and feature pooling in the vertical direction of human body. Besides, varying viewpoints in the horizontal direction of human body usually causes the data missing problem, $i.e.$, the appearances obtained in different orientations of the identical person could vary significantly. To address this problem, the orientation driven bag of appearances (ODBoA) is proposed to utilize person orientation information extracted by orientation estimation technic. To properly evaluate the proposed approach, we introduce a new re-identification dataset (Market-1203) based on the Market-1501 dataset and propose a new re-identification dataset (PKU-Reid). Both datasets contain multiple images captured in different body orientations for each person. Experimental results on three public datasets and two proposed datasets demonstrate the superiority of the proposed approach, indicating the effectiveness of body structure and orientation information for improving re-identification performance.
[ { "version": "v1", "created": "Mon, 9 May 2016 08:25:33 GMT" } ]
2016-05-10T00:00:00
[ [ "Ma", "Liqian", "" ], [ "Liu", "Hong", "" ], [ "Hu", "Liang", "" ], [ "Wang", "Can", "" ], [ "Sun", "Qianru", "" ] ]
TITLE: Orientation Driven Bag of Appearances for Person Re-identification ABSTRACT: Person re-identification (re-id) consists of associating individual across camera network, which is valuable for intelligent video surveillance and has drawn wide attention. Although person re-identification research is making progress, it still faces some challenges such as varying poses, illumination and viewpoints. For feature representation in re-identification, existing works usually use low-level descriptors which do not take full advantage of body structure information, resulting in low representation ability. %discrimination. To solve this problem, this paper proposes the mid-level body-structure based feature representation (BSFR) which introduces body structure pyramid for codebook learning and feature pooling in the vertical direction of human body. Besides, varying viewpoints in the horizontal direction of human body usually causes the data missing problem, $i.e.$, the appearances obtained in different orientations of the identical person could vary significantly. To address this problem, the orientation driven bag of appearances (ODBoA) is proposed to utilize person orientation information extracted by orientation estimation technic. To properly evaluate the proposed approach, we introduce a new re-identification dataset (Market-1203) based on the Market-1501 dataset and propose a new re-identification dataset (PKU-Reid). Both datasets contain multiple images captured in different body orientations for each person. Experimental results on three public datasets and two proposed datasets demonstrate the superiority of the proposed approach, indicating the effectiveness of body structure and orientation information for improving re-identification performance.
1605.02559
Olivier Colliot
Linda Marrakchi-Kacem (ARAMIS), Alexandre Vignaud (NEUROSPIN), Julien Sein (CRMBM), Johanne Germain (ARAMIS), Thomas R Henry (CMRR), Cyril Poupon (NEUROSPIN), Lucie Hertz-Pannier, St\'ephane Leh\'ericy (CENIR, ICM), Olivier Colliot (ARAMIS, ICM), Pierre-Fran\c{c}ois Van de Moortele (CMRR), Marie Chupin (ARAMIS, ICM)
Robust imaging of hippocampal inner structure at 7T: in vivo acquisition protocol and methodological choices
null
Magnetic Resonance Materials in Physics, Biology and Medicine, Springer Verlag, 2016
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
OBJECTIVE:Motion-robust multi-slab imaging of hippocampal inner structure in vivo at 7T.MATERIALS AND METHODS:Motion is a crucial issue for ultra-high resolution imaging, such as can be achieved with 7T MRI. An acquisition protocol was designed for imaging hippocampal inner structure at 7T. It relies on a compromise between anatomical details visibility and robustness to motion. In order to reduce acquisition time and motion artifacts, the full slab covering the hippocampus was split into separate slabs with lower acquisition time. A robust registration approach was implemented to combine the acquired slabs within a final 3D-consistent high-resolution slab covering the whole hippocampus. Evaluation was performed on 50 subjects overall, made of three groups of subjects acquired using three acquisition settings; it focused on three issues: visibility of hippocampal inner structure, robustness to motion artifacts and registration procedure performance.RESULTS:Overall, T2-weighted acquisitions with interleaved slabs proved robust. Multi-slab registration yielded high quality datasets in 96 % of the subjects, thus compatible with further analyses of hippocampal inner structure.CONCLUSION:Multi-slab acquisition and registration setting is efficient for reducing acquisition time and consequently motion artifacts for ultra-high resolution imaging of the inner structure of the hippocampus.
[ { "version": "v1", "created": "Mon, 9 May 2016 12:38:44 GMT" } ]
2016-05-10T00:00:00
[ [ "Marrakchi-Kacem", "Linda", "", "ARAMIS" ], [ "Vignaud", "Alexandre", "", "NEUROSPIN" ], [ "Sein", "Julien", "", "CRMBM" ], [ "Germain", "Johanne", "", "ARAMIS" ], [ "Henry", "Thomas R", "", "CMRR" ], [ "Poupon", "Cyril", "", "NEUROSPIN" ], [ "Hertz-Pannier", "Lucie", "", "CENIR, ICM" ], [ "Lehéricy", "Stéphane", "", "CENIR, ICM" ], [ "Colliot", "Olivier", "", "ARAMIS, ICM" ], [ "Van de Moortele", "Pierre-François", "", "CMRR" ], [ "Chupin", "Marie", "", "ARAMIS, ICM" ] ]
TITLE: Robust imaging of hippocampal inner structure at 7T: in vivo acquisition protocol and methodological choices ABSTRACT: OBJECTIVE:Motion-robust multi-slab imaging of hippocampal inner structure in vivo at 7T.MATERIALS AND METHODS:Motion is a crucial issue for ultra-high resolution imaging, such as can be achieved with 7T MRI. An acquisition protocol was designed for imaging hippocampal inner structure at 7T. It relies on a compromise between anatomical details visibility and robustness to motion. In order to reduce acquisition time and motion artifacts, the full slab covering the hippocampus was split into separate slabs with lower acquisition time. A robust registration approach was implemented to combine the acquired slabs within a final 3D-consistent high-resolution slab covering the whole hippocampus. Evaluation was performed on 50 subjects overall, made of three groups of subjects acquired using three acquisition settings; it focused on three issues: visibility of hippocampal inner structure, robustness to motion artifacts and registration procedure performance.RESULTS:Overall, T2-weighted acquisitions with interleaved slabs proved robust. Multi-slab registration yielded high quality datasets in 96 % of the subjects, thus compatible with further analyses of hippocampal inner structure.CONCLUSION:Multi-slab acquisition and registration setting is efficient for reducing acquisition time and consequently motion artifacts for ultra-high resolution imaging of the inner structure of the hippocampus.
1605.02560
Zi Wang
Zi Wang, Vyacheslav Karolis, Chiara Nosarti, Giovanni Montana
Studying the brain from adolescence to adulthood through sparse multi-view matrix factorisations
Submitted to the 6th International Workshop on Pattern Recognition in Neuroimaging (PRNI)
null
null
null
stat.AP cs.CV q-bio.NC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Men and women differ in specific cognitive abilities and in the expression of several neuropsychiatric conditions. Such findings could be attributed to sex hormones, brain differences, as well as a number of environmental variables. Existing research on identifying sex-related differences in brain structure have predominantly used cross-sectional studies to investigate, for instance, differences in average gray matter volumes (GMVs). In this article we explore the potential of a recently proposed multi-view matrix factorisation (MVMF) methodology to study structural brain changes in men and women that occur from adolescence to adulthood. MVMF is a multivariate variance decomposition technique that extends principal component analysis to "multi-view" datasets, i.e. where multiple and related groups of observations are available. In this application, each view represents a different age group. MVMF identifies latent factors explaining shared and age-specific contributions to the observed overall variability in GMVs over time. These latent factors can be used to produce low-dimensional visualisations of the data that emphasise age-specific effects once the shared effects have been accounted for. The analysis of two datasets consisting of individuals born prematurely as well as healthy controls provides evidence to suggest that the separation between males and females becomes increasingly larger as the brain transitions from adolescence to adulthood. We report on specific brain regions associated to these variance effects.
[ { "version": "v1", "created": "Mon, 9 May 2016 12:40:22 GMT" } ]
2016-05-10T00:00:00
[ [ "Wang", "Zi", "" ], [ "Karolis", "Vyacheslav", "" ], [ "Nosarti", "Chiara", "" ], [ "Montana", "Giovanni", "" ] ]
TITLE: Studying the brain from adolescence to adulthood through sparse multi-view matrix factorisations ABSTRACT: Men and women differ in specific cognitive abilities and in the expression of several neuropsychiatric conditions. Such findings could be attributed to sex hormones, brain differences, as well as a number of environmental variables. Existing research on identifying sex-related differences in brain structure have predominantly used cross-sectional studies to investigate, for instance, differences in average gray matter volumes (GMVs). In this article we explore the potential of a recently proposed multi-view matrix factorisation (MVMF) methodology to study structural brain changes in men and women that occur from adolescence to adulthood. MVMF is a multivariate variance decomposition technique that extends principal component analysis to "multi-view" datasets, i.e. where multiple and related groups of observations are available. In this application, each view represents a different age group. MVMF identifies latent factors explaining shared and age-specific contributions to the observed overall variability in GMVs over time. These latent factors can be used to produce low-dimensional visualisations of the data that emphasise age-specific effects once the shared effects have been accounted for. The analysis of two datasets consisting of individuals born prematurely as well as healthy controls provides evidence to suggest that the separation between males and females becomes increasingly larger as the brain transitions from adolescence to adulthood. We report on specific brain regions associated to these variance effects.
1605.02633
Chong You
Chong You, Chun-Guang Li, Daniel P. Robinson, Rene Vidal
Oracle Based Active Set Algorithm for Scalable Elastic Net Subspace Clustering
15 pages, 6 figures, accepted to CVPR 2016 for oral presentation
null
null
null
cs.LG cs.CV stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
State-of-the-art subspace clustering methods are based on expressing each data point as a linear combination of other data points while regularizing the matrix of coefficients with $\ell_1$, $\ell_2$ or nuclear norms. $\ell_1$ regularization is guaranteed to give a subspace-preserving affinity (i.e., there are no connections between points from different subspaces) under broad theoretical conditions, but the clusters may not be connected. $\ell_2$ and nuclear norm regularization often improve connectivity, but give a subspace-preserving affinity only for independent subspaces. Mixed $\ell_1$, $\ell_2$ and nuclear norm regularizations offer a balance between the subspace-preserving and connectedness properties, but this comes at the cost of increased computational complexity. This paper studies the geometry of the elastic net regularizer (a mixture of the $\ell_1$ and $\ell_2$ norms) and uses it to derive a provably correct and scalable active set method for finding the optimal coefficients. Our geometric analysis also provides a theoretical justification and a geometric interpretation for the balance between the connectedness (due to $\ell_2$ regularization) and subspace-preserving (due to $\ell_1$ regularization) properties for elastic net subspace clustering. Our experiments show that the proposed active set method not only achieves state-of-the-art clustering performance, but also efficiently handles large-scale datasets.
[ { "version": "v1", "created": "Mon, 9 May 2016 15:49:36 GMT" } ]
2016-05-10T00:00:00
[ [ "You", "Chong", "" ], [ "Li", "Chun-Guang", "" ], [ "Robinson", "Daniel P.", "" ], [ "Vidal", "Rene", "" ] ]
TITLE: Oracle Based Active Set Algorithm for Scalable Elastic Net Subspace Clustering ABSTRACT: State-of-the-art subspace clustering methods are based on expressing each data point as a linear combination of other data points while regularizing the matrix of coefficients with $\ell_1$, $\ell_2$ or nuclear norms. $\ell_1$ regularization is guaranteed to give a subspace-preserving affinity (i.e., there are no connections between points from different subspaces) under broad theoretical conditions, but the clusters may not be connected. $\ell_2$ and nuclear norm regularization often improve connectivity, but give a subspace-preserving affinity only for independent subspaces. Mixed $\ell_1$, $\ell_2$ and nuclear norm regularizations offer a balance between the subspace-preserving and connectedness properties, but this comes at the cost of increased computational complexity. This paper studies the geometry of the elastic net regularizer (a mixture of the $\ell_1$ and $\ell_2$ norms) and uses it to derive a provably correct and scalable active set method for finding the optimal coefficients. Our geometric analysis also provides a theoretical justification and a geometric interpretation for the balance between the connectedness (due to $\ell_2$ regularization) and subspace-preserving (due to $\ell_1$ regularization) properties for elastic net subspace clustering. Our experiments show that the proposed active set method not only achieves state-of-the-art clustering performance, but also efficiently handles large-scale datasets.
1506.03101
Bo Dai
Bo Dai, Niao He, Hanjun Dai, Le Song
Provable Bayesian Inference via Particle Mirror Descent
38 pages, 26 figures
null
null
null
cs.LG stat.CO stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Bayesian methods are appealing in their flexibility in modeling complex data and ability in capturing uncertainty in parameters. However, when Bayes' rule does not result in tractable closed-form, most approximate inference algorithms lack either scalability or rigorous guarantees. To tackle this challenge, we propose a simple yet provable algorithm, \emph{Particle Mirror Descent} (PMD), to iteratively approximate the posterior density. PMD is inspired by stochastic functional mirror descent where one descends in the density space using a small batch of data points at each iteration, and by particle filtering where one uses samples to approximate a function. We prove result of the first kind that, with $m$ particles, PMD provides a posterior density estimator that converges in terms of $KL$-divergence to the true posterior in rate $O(1/\sqrt{m})$. We demonstrate competitive empirical performances of PMD compared to several approximate inference algorithms in mixture models, logistic regression, sparse Gaussian processes and latent Dirichlet allocation on large scale datasets.
[ { "version": "v1", "created": "Tue, 9 Jun 2015 20:57:37 GMT" }, { "version": "v2", "created": "Tue, 3 May 2016 19:06:18 GMT" }, { "version": "v3", "created": "Thu, 5 May 2016 22:56:13 GMT" } ]
2016-05-09T00:00:00
[ [ "Dai", "Bo", "" ], [ "He", "Niao", "" ], [ "Dai", "Hanjun", "" ], [ "Song", "Le", "" ] ]
TITLE: Provable Bayesian Inference via Particle Mirror Descent ABSTRACT: Bayesian methods are appealing in their flexibility in modeling complex data and ability in capturing uncertainty in parameters. However, when Bayes' rule does not result in tractable closed-form, most approximate inference algorithms lack either scalability or rigorous guarantees. To tackle this challenge, we propose a simple yet provable algorithm, \emph{Particle Mirror Descent} (PMD), to iteratively approximate the posterior density. PMD is inspired by stochastic functional mirror descent where one descends in the density space using a small batch of data points at each iteration, and by particle filtering where one uses samples to approximate a function. We prove result of the first kind that, with $m$ particles, PMD provides a posterior density estimator that converges in terms of $KL$-divergence to the true posterior in rate $O(1/\sqrt{m})$. We demonstrate competitive empirical performances of PMD compared to several approximate inference algorithms in mixture models, logistic regression, sparse Gaussian processes and latent Dirichlet allocation on large scale datasets.
1512.04407
Arjun Chandrasekaran
Arjun Chandrasekaran, Ashwin K. Vijayakumar, Stanislaw Antol, Mohit Bansal, Dhruv Batra, C. Lawrence Zitnick and Devi Parikh
We Are Humor Beings: Understanding and Predicting Visual Humor
17 pages, 16 figures, 3 tables
null
null
null
cs.CV cs.CL cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Humor is an integral part of human lives. Despite being tremendously impactful, it is perhaps surprising that we do not have a detailed understanding of humor yet. As interactions between humans and AI systems increase, it is imperative that these systems are taught to understand subtleties of human expressions such as humor. In this work, we are interested in the question - what content in a scene causes it to be funny? As a first step towards understanding visual humor, we analyze the humor manifested in abstract scenes and design computational models for them. We collect two datasets of abstract scenes that facilitate the study of humor at both the scene-level and the object-level. We analyze the funny scenes and explore the different types of humor depicted in them via human studies. We model two tasks that we believe demonstrate an understanding of some aspects of visual humor. The tasks involve predicting the funniness of a scene and altering the funniness of a scene. We show that our models perform well quantitatively, and qualitatively through human studies. Our datasets are publicly available.
[ { "version": "v1", "created": "Mon, 14 Dec 2015 16:59:35 GMT" }, { "version": "v2", "created": "Wed, 16 Dec 2015 02:12:49 GMT" }, { "version": "v3", "created": "Sun, 10 Apr 2016 22:15:43 GMT" }, { "version": "v4", "created": "Thu, 5 May 2016 21:36:13 GMT" } ]
2016-05-09T00:00:00
[ [ "Chandrasekaran", "Arjun", "" ], [ "Vijayakumar", "Ashwin K.", "" ], [ "Antol", "Stanislaw", "" ], [ "Bansal", "Mohit", "" ], [ "Batra", "Dhruv", "" ], [ "Zitnick", "C. Lawrence", "" ], [ "Parikh", "Devi", "" ] ]
TITLE: We Are Humor Beings: Understanding and Predicting Visual Humor ABSTRACT: Humor is an integral part of human lives. Despite being tremendously impactful, it is perhaps surprising that we do not have a detailed understanding of humor yet. As interactions between humans and AI systems increase, it is imperative that these systems are taught to understand subtleties of human expressions such as humor. In this work, we are interested in the question - what content in a scene causes it to be funny? As a first step towards understanding visual humor, we analyze the humor manifested in abstract scenes and design computational models for them. We collect two datasets of abstract scenes that facilitate the study of humor at both the scene-level and the object-level. We analyze the funny scenes and explore the different types of humor depicted in them via human studies. We model two tasks that we believe demonstrate an understanding of some aspects of visual humor. The tasks involve predicting the funniness of a scene and altering the funniness of a scene. We show that our models perform well quantitatively, and qualitatively through human studies. Our datasets are publicly available.
1601.01396
arXiv Admin
George Tsatsanifos
On the Computation of the Optimal Connecting Points in Road Networks
This submission has been withdrawn by arXiv administrators due to disputed authorship
null
null
null
cs.DS
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper we consider a set of travelers, starting from likely different locations towards a common destination within a road network, and propose solutions to find the optimal connecting points for them. A connecting point is a vertex of the network where a subset of the travelers meet and continue traveling together towards the next connecting point or the destination. The notion of optimality is with regard to a given aggregated travel cost, e.g., travel distance or shared fuel cost. This problem by itself is new and we make it even more interesting (and complex) by considering affinity factors among the users, i.e., how much a user likes to travel together with another one. This plays a fundamental role in determining where the connecting points are and how subsets of travelers are formed. We propose three methods for addressing this problem, one that relies on a fast and greedy approach that finds a sub-optimal solution, and two others that yield globally optimal solution. We evaluate all proposed approaches through experiments, where collections of real datasets are used to assess the trade-offs, behavior and characteristics of each method.
[ { "version": "v1", "created": "Thu, 7 Jan 2016 04:25:27 GMT" }, { "version": "v2", "created": "Wed, 27 Apr 2016 12:15:03 GMT" }, { "version": "v3", "created": "Fri, 6 May 2016 17:30:25 GMT" } ]
2016-05-09T00:00:00
[ [ "Tsatsanifos", "George", "" ] ]
TITLE: On the Computation of the Optimal Connecting Points in Road Networks ABSTRACT: In this paper we consider a set of travelers, starting from likely different locations towards a common destination within a road network, and propose solutions to find the optimal connecting points for them. A connecting point is a vertex of the network where a subset of the travelers meet and continue traveling together towards the next connecting point or the destination. The notion of optimality is with regard to a given aggregated travel cost, e.g., travel distance or shared fuel cost. This problem by itself is new and we make it even more interesting (and complex) by considering affinity factors among the users, i.e., how much a user likes to travel together with another one. This plays a fundamental role in determining where the connecting points are and how subsets of travelers are formed. We propose three methods for addressing this problem, one that relies on a fast and greedy approach that finds a sub-optimal solution, and two others that yield globally optimal solution. We evaluate all proposed approaches through experiments, where collections of real datasets are used to assess the trade-offs, behavior and characteristics of each method.
1605.01744
David Cinciruk
Mengke Hu, David Cinciruk, and John MacLaren Walsh
Improving Automated Patent Claim Parsing: Dataset, System, and Experiments
null
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Off-the-shelf natural language processing software performs poorly when parsing patent claims owing to their use of irregular language relative to the corpora built from news articles and the web typically utilized to train this software. Stopping short of the extensive and expensive process of accumulating a large enough dataset to completely retrain parsers for patent claims, a method of adapting existing natural language processing software towards patent claims via forced part of speech tag correction is proposed. An Amazon Mechanical Turk collection campaign organized to generate a public corpus to train such an improved claim parsing system is discussed, identifying lessons learned during the campaign that can be of use in future NLP dataset collection campaigns with AMT. Experiments utilizing this corpus and other patent claim sets measure the parsing performance improvement garnered via the claim parsing system. Finally, the utility of the improved claim parsing system within other patent processing applications is demonstrated via experiments showing improved automated patent subject classification when the new claim parsing system is utilized to generate the features.
[ { "version": "v1", "created": "Thu, 5 May 2016 20:11:57 GMT" } ]
2016-05-09T00:00:00
[ [ "Hu", "Mengke", "" ], [ "Cinciruk", "David", "" ], [ "Walsh", "John MacLaren", "" ] ]
TITLE: Improving Automated Patent Claim Parsing: Dataset, System, and Experiments ABSTRACT: Off-the-shelf natural language processing software performs poorly when parsing patent claims owing to their use of irregular language relative to the corpora built from news articles and the web typically utilized to train this software. Stopping short of the extensive and expensive process of accumulating a large enough dataset to completely retrain parsers for patent claims, a method of adapting existing natural language processing software towards patent claims via forced part of speech tag correction is proposed. An Amazon Mechanical Turk collection campaign organized to generate a public corpus to train such an improved claim parsing system is discussed, identifying lessons learned during the campaign that can be of use in future NLP dataset collection campaigns with AMT. Experiments utilizing this corpus and other patent claim sets measure the parsing performance improvement garnered via the claim parsing system. Finally, the utility of the improved claim parsing system within other patent processing applications is demonstrated via experiments showing improved automated patent subject classification when the new claim parsing system is utilized to generate the features.
1605.01749
Paul Bertens
Paul Bertens
Rank Ordered Autoencoders
Personal project, 14 pages, 9 figures. For source code see: https://github.com/paulbertens
null
null
null
cs.LG stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
A new method for the unsupervised learning of sparse representations using autoencoders is proposed and implemented by ordering the output of the hidden units by their activation value and progressively reconstructing the input in this order. This can be done efficiently in parallel with the use of cumulative sums and sorting only slightly increasing the computational costs. Minimizing the difference of this progressive reconstruction with respect to the input can be seen as minimizing the number of active output units required for the reconstruction of the input. The model thus learns to reconstruct optimally using the least number of active output units. This leads to high sparsity without the need for extra hyperparameters, the amount of sparsity is instead implicitly learned by minimizing this progressive reconstruction error. Results of the trained model are given for patches of the CIFAR10 dataset, showing rapid convergence of features and extremely sparse output activations while maintaining a minimal reconstruction error and showing extreme robustness to overfitting. Additionally the reconstruction as function of number of active units is presented which shows the autoencoder learns a rank order code over the input where the highest ranked units correspond to the highest decrease in reconstruction error.
[ { "version": "v1", "created": "Thu, 5 May 2016 20:33:38 GMT" } ]
2016-05-09T00:00:00
[ [ "Bertens", "Paul", "" ] ]
TITLE: Rank Ordered Autoencoders ABSTRACT: A new method for the unsupervised learning of sparse representations using autoencoders is proposed and implemented by ordering the output of the hidden units by their activation value and progressively reconstructing the input in this order. This can be done efficiently in parallel with the use of cumulative sums and sorting only slightly increasing the computational costs. Minimizing the difference of this progressive reconstruction with respect to the input can be seen as minimizing the number of active output units required for the reconstruction of the input. The model thus learns to reconstruct optimally using the least number of active output units. This leads to high sparsity without the need for extra hyperparameters, the amount of sparsity is instead implicitly learned by minimizing this progressive reconstruction error. Results of the trained model are given for patches of the CIFAR10 dataset, showing rapid convergence of features and extremely sparse output activations while maintaining a minimal reconstruction error and showing extreme robustness to overfitting. Additionally the reconstruction as function of number of active units is presented which shows the autoencoder learns a rank order code over the input where the highest ranked units correspond to the highest decrease in reconstruction error.
1605.01790
Kristjan Greenewald
Kristjan Greenewald, Edmund Zelnio, Alfred Hero
Robust SAR STAP via Kronecker Decomposition
to appear at IEEE AES. arXiv admin note: text overlap with arXiv:1604.03622, arXiv:1501.07481
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
This paper proposes a spatio-temporal decomposition for the detection of moving targets in multiantenna SAR. As a high resolution radar imaging modality, SAR detects and localizes non-moving targets accurately, giving it an advantage over lower resolution GMTI radars. Moving target detection is more challenging due to target smearing and masking by clutter. Space-time adaptive processing (STAP) is often used to remove the stationary clutter and enhance the moving targets. In this work, it is shown that the performance of STAP can be improved by modeling the clutter covariance as a space vs. time Kronecker product with low rank factors. Based on this model, a low-rank Kronecker product covariance estimation algorithm is proposed, and a novel separable clutter cancelation filter based on the Kronecker covariance estimate is introduced. The proposed method provides orders of magnitude reduction in the required number of training samples, as well as improved robustness to corruption of the training data. Simulation results and experiments using the Gotcha SAR GMTI challenge dataset are presented that confirm the advantages of our approach relative to existing techniques.
[ { "version": "v1", "created": "Thu, 5 May 2016 23:53:32 GMT" } ]
2016-05-09T00:00:00
[ [ "Greenewald", "Kristjan", "" ], [ "Zelnio", "Edmund", "" ], [ "Hero", "Alfred", "" ] ]
TITLE: Robust SAR STAP via Kronecker Decomposition ABSTRACT: This paper proposes a spatio-temporal decomposition for the detection of moving targets in multiantenna SAR. As a high resolution radar imaging modality, SAR detects and localizes non-moving targets accurately, giving it an advantage over lower resolution GMTI radars. Moving target detection is more challenging due to target smearing and masking by clutter. Space-time adaptive processing (STAP) is often used to remove the stationary clutter and enhance the moving targets. In this work, it is shown that the performance of STAP can be improved by modeling the clutter covariance as a space vs. time Kronecker product with low rank factors. Based on this model, a low-rank Kronecker product covariance estimation algorithm is proposed, and a novel separable clutter cancelation filter based on the Kronecker covariance estimate is introduced. The proposed method provides orders of magnitude reduction in the required number of training samples, as well as improved robustness to corruption of the training data. Simulation results and experiments using the Gotcha SAR GMTI challenge dataset are presented that confirm the advantages of our approach relative to existing techniques.
1605.01832
Hanxiao Liu
Hanxiao Liu, Yiming Yang
Cross-Graph Learning of Multi-Relational Associations
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Cross-graph Relational Learning (CGRL) refers to the problem of predicting the strengths or labels of multi-relational tuples of heterogeneous object types, through the joint inference over multiple graphs which specify the internal connections among each type of objects. CGRL is an open challenge in machine learning due to the daunting number of all possible tuples to deal with when the numbers of nodes in multiple graphs are large, and because the labeled training instances are extremely sparse as typical. Existing methods such as tensor factorization or tensor-kernel machines do not work well because of the lack of convex formulation for the optimization of CGRL models, the poor scalability of the algorithms in handling combinatorial numbers of tuples, and/or the non-transductive nature of the learning methods which limits their ability to leverage unlabeled data in training. This paper proposes a novel framework which formulates CGRL as a convex optimization problem, enables transductive learning using both labeled and unlabeled tuples, and offers a scalable algorithm that guarantees the optimal solution and enjoys a linear time complexity with respect to the sizes of input graphs. In our experiments with a subset of DBLP publication records and an Enzyme multi-source dataset, the proposed method successfully scaled to the large cross-graph inference problem, and outperformed other representative approaches significantly.
[ { "version": "v1", "created": "Fri, 6 May 2016 06:15:20 GMT" } ]
2016-05-09T00:00:00
[ [ "Liu", "Hanxiao", "" ], [ "Yang", "Yiming", "" ] ]
TITLE: Cross-Graph Learning of Multi-Relational Associations ABSTRACT: Cross-graph Relational Learning (CGRL) refers to the problem of predicting the strengths or labels of multi-relational tuples of heterogeneous object types, through the joint inference over multiple graphs which specify the internal connections among each type of objects. CGRL is an open challenge in machine learning due to the daunting number of all possible tuples to deal with when the numbers of nodes in multiple graphs are large, and because the labeled training instances are extremely sparse as typical. Existing methods such as tensor factorization or tensor-kernel machines do not work well because of the lack of convex formulation for the optimization of CGRL models, the poor scalability of the algorithms in handling combinatorial numbers of tuples, and/or the non-transductive nature of the learning methods which limits their ability to leverage unlabeled data in training. This paper proposes a novel framework which formulates CGRL as a convex optimization problem, enables transductive learning using both labeled and unlabeled tuples, and offers a scalable algorithm that guarantees the optimal solution and enjoys a linear time complexity with respect to the sizes of input graphs. In our experiments with a subset of DBLP publication records and an Enzyme multi-source dataset, the proposed method successfully scaled to the large cross-graph inference problem, and outperformed other representative approaches significantly.
1605.01843
Shaodi You
Shaodi You, Nick Barnes and Janine Walker
Perceptually Consistent Color-to-Gray Image Conversion
18 pages
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this paper, we propose a color to grayscale image conversion algorithm (C2G) that aims to preserve the perceptual properties of the color image as much as possible. To this end, we propose measures for two perceptual properties based on contemporary research in vision science: brightness and multi-scale contrast. The brightness measurement is based on the idea that the brightness of a grayscale image will affect the perception of the probability of color information. The color contrast measurement is based on the idea that the contrast of a given pixel to its surroundings can be measured as a linear combination of color contrast at different scales. Based on these measures we propose a graph based optimization framework to balance the brightness and contrast measurements. To solve the optimization, an $\ell_1$-norm based method is provided which converts color discontinuities to brightness discontinuities. To validate our methods, we evaluate against the existing \cadik and Color250 datasets, and against NeoColor, a new dataset that improves over existing C2G datasets. NeoColor contains around 300 images from typical C2G scenarios, including: commercial photograph, printing, books, magazines, masterpiece artworks and computer designed graphics. We show improvements in metrics of performance, and further through a user study, we validate the performance of both the algorithm and the metric.
[ { "version": "v1", "created": "Fri, 6 May 2016 07:13:48 GMT" } ]
2016-05-09T00:00:00
[ [ "You", "Shaodi", "" ], [ "Barnes", "Nick", "" ], [ "Walker", "Janine", "" ] ]
TITLE: Perceptually Consistent Color-to-Gray Image Conversion ABSTRACT: In this paper, we propose a color to grayscale image conversion algorithm (C2G) that aims to preserve the perceptual properties of the color image as much as possible. To this end, we propose measures for two perceptual properties based on contemporary research in vision science: brightness and multi-scale contrast. The brightness measurement is based on the idea that the brightness of a grayscale image will affect the perception of the probability of color information. The color contrast measurement is based on the idea that the contrast of a given pixel to its surroundings can be measured as a linear combination of color contrast at different scales. Based on these measures we propose a graph based optimization framework to balance the brightness and contrast measurements. To solve the optimization, an $\ell_1$-norm based method is provided which converts color discontinuities to brightness discontinuities. To validate our methods, we evaluate against the existing \cadik and Color250 datasets, and against NeoColor, a new dataset that improves over existing C2G datasets. NeoColor contains around 300 images from typical C2G scenarios, including: commercial photograph, printing, books, magazines, masterpiece artworks and computer designed graphics. We show improvements in metrics of performance, and further through a user study, we validate the performance of both the algorithm and the metric.
1605.02026
Thomas Goldstein
Gavin Taylor, Ryan Burmeister, Zheng Xu, Bharat Singh, Ankit Patel, Tom Goldstein
Training Neural Networks Without Gradients: A Scalable ADMM Approach
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
With the growing importance of large network models and enormous training datasets, GPUs have become increasingly necessary to train neural networks. This is largely because conventional optimization algorithms rely on stochastic gradient methods that don't scale well to large numbers of cores in a cluster setting. Furthermore, the convergence of all gradient methods, including batch methods, suffers from common problems like saturation effects, poor conditioning, and saddle points. This paper explores an unconventional training method that uses alternating direction methods and Bregman iteration to train networks without gradient descent steps. The proposed method reduces the network training problem to a sequence of minimization sub-steps that can each be solved globally in closed form. The proposed method is advantageous because it avoids many of the caveats that make gradient methods slow on highly non-convex problems. The method exhibits strong scaling in the distributed setting, yielding linear speedups even when split over thousands of cores.
[ { "version": "v1", "created": "Fri, 6 May 2016 18:38:45 GMT" } ]
2016-05-09T00:00:00
[ [ "Taylor", "Gavin", "" ], [ "Burmeister", "Ryan", "" ], [ "Xu", "Zheng", "" ], [ "Singh", "Bharat", "" ], [ "Patel", "Ankit", "" ], [ "Goldstein", "Tom", "" ] ]
TITLE: Training Neural Networks Without Gradients: A Scalable ADMM Approach ABSTRACT: With the growing importance of large network models and enormous training datasets, GPUs have become increasingly necessary to train neural networks. This is largely because conventional optimization algorithms rely on stochastic gradient methods that don't scale well to large numbers of cores in a cluster setting. Furthermore, the convergence of all gradient methods, including batch methods, suffers from common problems like saturation effects, poor conditioning, and saddle points. This paper explores an unconventional training method that uses alternating direction methods and Bregman iteration to train networks without gradient descent steps. The proposed method reduces the network training problem to a sequence of minimization sub-steps that can each be solved globally in closed form. The proposed method is advantageous because it avoids many of the caveats that make gradient methods slow on highly non-convex problems. The method exhibits strong scaling in the distributed setting, yielding linear speedups even when split over thousands of cores.
1412.4564
Karel Lenc
Andrea Vedaldi, Karel Lenc
MatConvNet - Convolutional Neural Networks for MATLAB
Updated for release v1.0-beta20
null
null
null
cs.CV cs.LG cs.MS cs.NE
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
MatConvNet is an implementation of Convolutional Neural Networks (CNNs) for MATLAB. The toolbox is designed with an emphasis on simplicity and flexibility. It exposes the building blocks of CNNs as easy-to-use MATLAB functions, providing routines for computing linear convolutions with filter banks, feature pooling, and many more. In this manner, MatConvNet allows fast prototyping of new CNN architectures; at the same time, it supports efficient computation on CPU and GPU allowing to train complex models on large datasets such as ImageNet ILSVRC. This document provides an overview of CNNs and how they are implemented in MatConvNet and gives the technical details of each computational block in the toolbox.
[ { "version": "v1", "created": "Mon, 15 Dec 2014 12:23:35 GMT" }, { "version": "v2", "created": "Sun, 21 Jun 2015 15:35:25 GMT" }, { "version": "v3", "created": "Thu, 5 May 2016 14:31:06 GMT" } ]
2016-05-06T00:00:00
[ [ "Vedaldi", "Andrea", "" ], [ "Lenc", "Karel", "" ] ]
TITLE: MatConvNet - Convolutional Neural Networks for MATLAB ABSTRACT: MatConvNet is an implementation of Convolutional Neural Networks (CNNs) for MATLAB. The toolbox is designed with an emphasis on simplicity and flexibility. It exposes the building blocks of CNNs as easy-to-use MATLAB functions, providing routines for computing linear convolutions with filter banks, feature pooling, and many more. In this manner, MatConvNet allows fast prototyping of new CNN architectures; at the same time, it supports efficient computation on CPU and GPU allowing to train complex models on large datasets such as ImageNet ILSVRC. This document provides an overview of CNNs and how they are implemented in MatConvNet and gives the technical details of each computational block in the toolbox.
1509.00239
Jeremiah Blocki
Jeremiah Blocki and Anupam Datta
CASH: A Cost Asymmetric Secure Hash Algorithm for Optimal Password Protection
29th IEEE Computer Security Foundations Symposium (Full Version)
null
null
null
cs.CR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
An adversary who has obtained the cryptographic hash of a user's password can mount an offline attack to crack the password by comparing this hash value with the cryptographic hashes of likely password guesses. This offline attacker is limited only by the resources he is willing to invest to crack the password. Key-stretching tools can help mitigate the threat of offline attacks by making each password guess more expensive for the adversary to verify. However, key-stretching increases authentication costs for a legitimate authentication server. We introduce a novel Stackelberg game model which captures the essential elements of this interaction between a defender and an offline attacker. We then introduce Cost Asymmetric Secure Hash (CASH), a randomized key-stretching mechanism that minimizes the fraction of passwords that would be cracked by a rational offline attacker without increasing amortized authentication costs for the legitimate authentication server. CASH is motivated by the observation that the legitimate authentication server will typically run the authentication procedure to verify a correct password, while an offline adversary will typically use incorrect password guesses. By using randomization we can ensure that the amortized cost of running CASH to verify a correct password guess is significantly smaller than the cost of rejecting an incorrect password. Using our Stackelberg game framework we can quantify the quality of the underlying CASH running time distribution in terms of the fraction of passwords that a rational offline adversary would crack. We provide an efficient algorithm to compute high quality CASH distributions for the defender. Finally, we analyze CASH using empirical data from two large scale password frequency datasets. Our analysis shows that CASH can significantly reduce (up to $50\%$) the fraction of password cracked by a rational offline adversary.
[ { "version": "v1", "created": "Tue, 1 Sep 2015 11:45:56 GMT" }, { "version": "v2", "created": "Wed, 4 May 2016 22:05:14 GMT" } ]
2016-05-06T00:00:00
[ [ "Blocki", "Jeremiah", "" ], [ "Datta", "Anupam", "" ] ]
TITLE: CASH: A Cost Asymmetric Secure Hash Algorithm for Optimal Password Protection ABSTRACT: An adversary who has obtained the cryptographic hash of a user's password can mount an offline attack to crack the password by comparing this hash value with the cryptographic hashes of likely password guesses. This offline attacker is limited only by the resources he is willing to invest to crack the password. Key-stretching tools can help mitigate the threat of offline attacks by making each password guess more expensive for the adversary to verify. However, key-stretching increases authentication costs for a legitimate authentication server. We introduce a novel Stackelberg game model which captures the essential elements of this interaction between a defender and an offline attacker. We then introduce Cost Asymmetric Secure Hash (CASH), a randomized key-stretching mechanism that minimizes the fraction of passwords that would be cracked by a rational offline attacker without increasing amortized authentication costs for the legitimate authentication server. CASH is motivated by the observation that the legitimate authentication server will typically run the authentication procedure to verify a correct password, while an offline adversary will typically use incorrect password guesses. By using randomization we can ensure that the amortized cost of running CASH to verify a correct password guess is significantly smaller than the cost of rejecting an incorrect password. Using our Stackelberg game framework we can quantify the quality of the underlying CASH running time distribution in terms of the fraction of passwords that a rational offline adversary would crack. We provide an efficient algorithm to compute high quality CASH distributions for the defender. Finally, we analyze CASH using empirical data from two large scale password frequency datasets. Our analysis shows that CASH can significantly reduce (up to $50\%$) the fraction of password cracked by a rational offline adversary.
1602.02481
Sungjoon Choi
Sungjoon Choi, Qian-Yi Zhou, Stephen Miller, and Vladlen Koltun
A Large Dataset of Object Scans
Technical report
null
null
null
cs.CV cs.GR
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We have created a dataset of more than ten thousand 3D scans of real objects. To create the dataset, we recruited 70 operators, equipped them with consumer-grade mobile 3D scanning setups, and paid them to scan objects in their environments. The operators scanned objects of their choosing, outside the laboratory and without direct supervision by computer vision professionals. The result is a large and diverse collection of object scans: from shoes, mugs, and toys to grand pianos, construction vehicles, and large outdoor sculptures. We worked with an attorney to ensure that data acquisition did not violate privacy constraints. The acquired data was irrevocably placed in the public domain and is available freely at http://redwood-data.org/3dscan .
[ { "version": "v1", "created": "Mon, 8 Feb 2016 07:20:52 GMT" }, { "version": "v2", "created": "Tue, 9 Feb 2016 17:21:24 GMT" }, { "version": "v3", "created": "Thu, 5 May 2016 05:35:48 GMT" } ]
2016-05-06T00:00:00
[ [ "Choi", "Sungjoon", "" ], [ "Zhou", "Qian-Yi", "" ], [ "Miller", "Stephen", "" ], [ "Koltun", "Vladlen", "" ] ]
TITLE: A Large Dataset of Object Scans ABSTRACT: We have created a dataset of more than ten thousand 3D scans of real objects. To create the dataset, we recruited 70 operators, equipped them with consumer-grade mobile 3D scanning setups, and paid them to scan objects in their environments. The operators scanned objects of their choosing, outside the laboratory and without direct supervision by computer vision professionals. The result is a large and diverse collection of object scans: from shoes, mugs, and toys to grand pianos, construction vehicles, and large outdoor sculptures. We worked with an attorney to ensure that data acquisition did not violate privacy constraints. The acquired data was irrevocably placed in the public domain and is available freely at http://redwood-data.org/3dscan .
1605.00971
Peter Dugan Dr
Peter J. Dugan, Christopher W. Clark, Yann Andr\'e LeCun, Sofie M. Van Parijs
Phase 1: DCL System Research Using Advanced Approaches for Land-based or Ship-based Real-Time Recognition and Localization of Marine Mammals - HPC System Implementation
Year 1 National Oceanic Partnership Program Report, sponsored ONR, NFWF. N000141210585
null
null
N000141210585
cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We aim to investigate advancing the state of the art of detection, classification and localization (DCL) in the field of bioacoustics. The two primary goals are to develop transferable technologies for detection and classification in: (1) the area of advanced algorithms, such as deep learning and other methods; and (2) advanced systems, capable of real-time and archival and processing. This project will focus on long-term, continuous datasets to provide automatic recognition, minimizing human time to annotate the signals. Effort will begin by focusing on several years of multi-channel acoustic data collected in the Stellwagen Bank National Marine Sanctuary (SBNMS) between 2006 and 2010. Our efforts will incorporate existing technologies in the bioacoustics signal processing community, advanced high performance computing (HPC) systems, and new approaches aimed at automatically detecting-classifying and measuring features for species-specific marine mammal sounds within passive acoustic data.
[ { "version": "v1", "created": "Tue, 3 May 2016 16:35:35 GMT" }, { "version": "v2", "created": "Thu, 5 May 2016 18:27:35 GMT" } ]
2016-05-06T00:00:00
[ [ "Dugan", "Peter J.", "" ], [ "Clark", "Christopher W.", "" ], [ "LeCun", "Yann André", "" ], [ "Van Parijs", "Sofie M.", "" ] ]
TITLE: Phase 1: DCL System Research Using Advanced Approaches for Land-based or Ship-based Real-Time Recognition and Localization of Marine Mammals - HPC System Implementation ABSTRACT: We aim to investigate advancing the state of the art of detection, classification and localization (DCL) in the field of bioacoustics. The two primary goals are to develop transferable technologies for detection and classification in: (1) the area of advanced algorithms, such as deep learning and other methods; and (2) advanced systems, capable of real-time and archival and processing. This project will focus on long-term, continuous datasets to provide automatic recognition, minimizing human time to annotate the signals. Effort will begin by focusing on several years of multi-channel acoustic data collected in the Stellwagen Bank National Marine Sanctuary (SBNMS) between 2006 and 2010. Our efforts will incorporate existing technologies in the bioacoustics signal processing community, advanced high performance computing (HPC) systems, and new approaches aimed at automatically detecting-classifying and measuring features for species-specific marine mammal sounds within passive acoustic data.
1605.00972
Peter Dugan Dr
Peter J. Dugan, Christopher W. Clark, Yann Andr\'e LeCun, Sofie M. Van Parijs
Phase 2: DCL System Using Deep Learning Approaches for Land-based or Ship-based Real-Time Recognition and Localization of Marine Mammals - Machine Learning Detection Algorithms
National Oceanic Partnership Program (NOPP) sponsored by ONR and NFWF: N000141210585
null
null
N000141210585
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Overarching goals for this work aim to advance the state of the art for detection, classification and localization (DCL) in the field of bioacoustics. This goal is primarily achieved by building a generic framework for detection-classification (DC) using a fast, efficient and scalable architecture, demonstrating the capabilities of this system using on a variety of low-frequency mid-frequency cetacean sounds. Two primary goals are to develop transferable technologies for detection and classification in, one: the area of advanced algorithms, such as deep learning and other methods; and two: advanced systems, capable of real-time and archival processing. For each key area, we will focus on producing publications from this work and providing tools and software to the community where/when possible. Currently massive amounts of acoustic data are being collected by various institutions, corporations and national defense agencies. The long-term goal is to provide technical capability to analyze the data using automatic algorithms for (DC) based on machine intelligence. The goal of the automation is to provide effective and efficient mechanisms by which to process large acoustic datasets for understanding the bioacoustic behaviors of marine mammals. This capability will provide insights into the potential ecological impacts and influences of anthropogenic ocean sounds. This work focuses on building technologies using a maturity model based on DARPA 6.1 and 6.2 processes, for basic and applied research, respectively.
[ { "version": "v1", "created": "Tue, 3 May 2016 16:36:30 GMT" }, { "version": "v2", "created": "Thu, 5 May 2016 18:28:21 GMT" } ]
2016-05-06T00:00:00
[ [ "Dugan", "Peter J.", "" ], [ "Clark", "Christopher W.", "" ], [ "LeCun", "Yann André", "" ], [ "Van Parijs", "Sofie M.", "" ] ]
TITLE: Phase 2: DCL System Using Deep Learning Approaches for Land-based or Ship-based Real-Time Recognition and Localization of Marine Mammals - Machine Learning Detection Algorithms ABSTRACT: Overarching goals for this work aim to advance the state of the art for detection, classification and localization (DCL) in the field of bioacoustics. This goal is primarily achieved by building a generic framework for detection-classification (DC) using a fast, efficient and scalable architecture, demonstrating the capabilities of this system using on a variety of low-frequency mid-frequency cetacean sounds. Two primary goals are to develop transferable technologies for detection and classification in, one: the area of advanced algorithms, such as deep learning and other methods; and two: advanced systems, capable of real-time and archival processing. For each key area, we will focus on producing publications from this work and providing tools and software to the community where/when possible. Currently massive amounts of acoustic data are being collected by various institutions, corporations and national defense agencies. The long-term goal is to provide technical capability to analyze the data using automatic algorithms for (DC) based on machine intelligence. The goal of the automation is to provide effective and efficient mechanisms by which to process large acoustic datasets for understanding the bioacoustic behaviors of marine mammals. This capability will provide insights into the potential ecological impacts and influences of anthropogenic ocean sounds. This work focuses on building technologies using a maturity model based on DARPA 6.1 and 6.2 processes, for basic and applied research, respectively.
1605.00982
Peter Dugan Dr
Peter J. Dugan, Christopher W. Clark, Yann Andr\'e LeCun, Sofie M. Van Parijs
Phase 4: DCL System Using Deep Learning Approaches for Land-Based or Ship-Based Real-Time Recognition and Localization of Marine Mammals - Distributed Processing and Big Data Applications
National Oceanic Partnership Program (NOPP) sponsored by ONR and NFWF
null
null
N000141210585
cs.DC
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
While the animal bioacoustics community at large is collecting huge amounts of acoustic data at an unprecedented pace, processing these data is problematic. Currently in bioacoustics, there is no effective way to achieve high performance computing using commericial off the shelf (COTS) or government off the shelf (GOTS) tools. Although several advances have been made in the open source and commercial software community, these offerings either support specific applications that do not integrate well with data formats in bioacoustics or they are too general. Furthermore, complex algorithms that use deep learning strategies require special considerations, such as very large libraiers of exemplars (whale sounds) readily available for algorithm training and testing. Detection-classification for passive acoustics is a data-mining strategy and our goals are aligned with best practices that appeal to the general data mining and machine learning communities where the problem of processing large data is common. Therefore, the objective of this work is to advance the state-of-the art for data-mining large passive acoustic datasets as they pertain to bioacoustics. With this basic deficiency recognized at the forefront, portions of the grant were dedicated to fostering deep-learning by way of international competitions (kaggle.com) meant to attract deep-learning solutions. The focus of this early work was targeted to make significant progress in addressing big data systems and advanced algorithms over the duration of the grant from 2012 to 2015. This early work provided simulataneous advances in systems-algorithms research while supporting various collaborations and projects.
[ { "version": "v1", "created": "Tue, 3 May 2016 16:54:07 GMT" }, { "version": "v2", "created": "Thu, 5 May 2016 18:35:16 GMT" } ]
2016-05-06T00:00:00
[ [ "Dugan", "Peter J.", "" ], [ "Clark", "Christopher W.", "" ], [ "LeCun", "Yann André", "" ], [ "Van Parijs", "Sofie M.", "" ] ]
TITLE: Phase 4: DCL System Using Deep Learning Approaches for Land-Based or Ship-Based Real-Time Recognition and Localization of Marine Mammals - Distributed Processing and Big Data Applications ABSTRACT: While the animal bioacoustics community at large is collecting huge amounts of acoustic data at an unprecedented pace, processing these data is problematic. Currently in bioacoustics, there is no effective way to achieve high performance computing using commericial off the shelf (COTS) or government off the shelf (GOTS) tools. Although several advances have been made in the open source and commercial software community, these offerings either support specific applications that do not integrate well with data formats in bioacoustics or they are too general. Furthermore, complex algorithms that use deep learning strategies require special considerations, such as very large libraiers of exemplars (whale sounds) readily available for algorithm training and testing. Detection-classification for passive acoustics is a data-mining strategy and our goals are aligned with best practices that appeal to the general data mining and machine learning communities where the problem of processing large data is common. Therefore, the objective of this work is to advance the state-of-the art for data-mining large passive acoustic datasets as they pertain to bioacoustics. With this basic deficiency recognized at the forefront, portions of the grant were dedicated to fostering deep-learning by way of international competitions (kaggle.com) meant to attract deep-learning solutions. The focus of this early work was targeted to make significant progress in addressing big data systems and advanced algorithms over the duration of the grant from 2012 to 2015. This early work provided simulataneous advances in systems-algorithms research while supporting various collaborations and projects.
1605.01534
Mohit Yadav
Mohit Yadav, Pankaj Malhotra, Lovekesh Vig, K Sriram, and Gautam Shroff
ODE - Augmented Training Improves Anomaly Detection in Sensor Data from Machines
Published at NIPS Time-series Workshop - 2015
null
null
null
cs.AI
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Machines of all kinds from vehicles to industrial equipment are increasingly instrumented with hundreds of sensors. Using such data to detect anomalous behaviour is critical for safety and efficient maintenance. However, anomalies occur rarely and with great variety in such systems, so there is often insufficient anomalous data to build reliable detectors. A standard approach to mitigate this problem is to use one class methods relying only on data from normal behaviour. Unfortunately, even these approaches are more likely to fail in the scenario of a dynamical system with manual control input(s). Normal behaviour in response to novel control input(s) might look very different to the learned detector which may be incorrectly detected as anomalous. In this paper, we address this issue by modelling time-series via Ordinary Differential Equations (ODE) and utilising such an ODE model to simulate the behaviour of dynamical systems under varying control inputs. The available data is then augmented with data generated from the ODE, and the anomaly detector is retrained on this augmented dataset. Experiments demonstrate that ODE-augmented training data allows better coverage of possible control input(s) and results in learning more accurate distinctions between normal and anomalous behaviour in time-series.
[ { "version": "v1", "created": "Thu, 5 May 2016 09:15:55 GMT" } ]
2016-05-06T00:00:00
[ [ "Yadav", "Mohit", "" ], [ "Malhotra", "Pankaj", "" ], [ "Vig", "Lovekesh", "" ], [ "Sriram", "K", "" ], [ "Shroff", "Gautam", "" ] ]
TITLE: ODE - Augmented Training Improves Anomaly Detection in Sensor Data from Machines ABSTRACT: Machines of all kinds from vehicles to industrial equipment are increasingly instrumented with hundreds of sensors. Using such data to detect anomalous behaviour is critical for safety and efficient maintenance. However, anomalies occur rarely and with great variety in such systems, so there is often insufficient anomalous data to build reliable detectors. A standard approach to mitigate this problem is to use one class methods relying only on data from normal behaviour. Unfortunately, even these approaches are more likely to fail in the scenario of a dynamical system with manual control input(s). Normal behaviour in response to novel control input(s) might look very different to the learned detector which may be incorrectly detected as anomalous. In this paper, we address this issue by modelling time-series via Ordinary Differential Equations (ODE) and utilising such an ODE model to simulate the behaviour of dynamical systems under varying control inputs. The available data is then augmented with data generated from the ODE, and the anomaly detector is retrained on this augmented dataset. Experiments demonstrate that ODE-augmented training data allows better coverage of possible control input(s) and results in learning more accurate distinctions between normal and anomalous behaviour in time-series.
1605.01623
Bo Han
Bo Han and Ivor W. Tsang and Ling Chen
On the Convergence of A Family of Robust Losses for Stochastic Gradient Descent
null
null
null
null
cs.LG
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The convergence of Stochastic Gradient Descent (SGD) using convex loss functions has been widely studied. However, vanilla SGD methods using convex losses cannot perform well with noisy labels, which adversely affect the update of the primal variable in SGD methods. Unfortunately, noisy labels are ubiquitous in real world applications such as crowdsourcing. To handle noisy labels, in this paper, we present a family of robust losses for SGD methods. By employing our robust losses, SGD methods successfully reduce negative effects caused by noisy labels on each update of the primal variable. We not only reveal that the convergence rate is O(1/T) for SGD methods using robust losses, but also provide the robustness analysis on two representative robust losses. Comprehensive experimental results on six real-world datasets show that SGD methods using robust losses are obviously more robust than other baseline methods in most situations with fast convergence.
[ { "version": "v1", "created": "Thu, 5 May 2016 15:22:46 GMT" } ]
2016-05-06T00:00:00
[ [ "Han", "Bo", "" ], [ "Tsang", "Ivor W.", "" ], [ "Chen", "Ling", "" ] ]
TITLE: On the Convergence of A Family of Robust Losses for Stochastic Gradient Descent ABSTRACT: The convergence of Stochastic Gradient Descent (SGD) using convex loss functions has been widely studied. However, vanilla SGD methods using convex losses cannot perform well with noisy labels, which adversely affect the update of the primal variable in SGD methods. Unfortunately, noisy labels are ubiquitous in real world applications such as crowdsourcing. To handle noisy labels, in this paper, we present a family of robust losses for SGD methods. By employing our robust losses, SGD methods successfully reduce negative effects caused by noisy labels on each update of the primal variable. We not only reveal that the convergence rate is O(1/T) for SGD methods using robust losses, but also provide the robustness analysis on two representative robust losses. Comprehensive experimental results on six real-world datasets show that SGD methods using robust losses are obviously more robust than other baseline methods in most situations with fast convergence.
1605.01655
Saif Mohammad Dr.
Saif M. Mohammad, Parinaz Sobhani, and Svetlana Kiritchenko
Stance and Sentiment in Tweets
22 pages
null
null
null
cs.CL
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We can often detect from a person's utterances whether he/she is in favor of or against a given target entity -- their stance towards the target. However, a person may express the same stance towards a target by using negative or positive language. Here for the first time we present a dataset of tweet--target pairs annotated for both stance and sentiment. The targets may or may not be referred to in the tweets, and they may or may not be the target of opinion in the tweets. Partitions of this dataset were used as training and test sets in a SemEval-2016 shared task competition. We propose a simple stance detection system that outperforms submissions from all 19 teams that participated in the shared task. Additionally, access to both stance and sentiment annotations allows us to explore several research questions. We show that while knowing the sentiment expressed by a tweet is beneficial for stance classification, it alone is not sufficient. Finally, we use additional unlabeled data through distant supervision techniques and word embeddings to further improve stance classification.
[ { "version": "v1", "created": "Thu, 5 May 2016 17:07:54 GMT" } ]
2016-05-06T00:00:00
[ [ "Mohammad", "Saif M.", "" ], [ "Sobhani", "Parinaz", "" ], [ "Kiritchenko", "Svetlana", "" ] ]
TITLE: Stance and Sentiment in Tweets ABSTRACT: We can often detect from a person's utterances whether he/she is in favor of or against a given target entity -- their stance towards the target. However, a person may express the same stance towards a target by using negative or positive language. Here for the first time we present a dataset of tweet--target pairs annotated for both stance and sentiment. The targets may or may not be referred to in the tweets, and they may or may not be the target of opinion in the tweets. Partitions of this dataset were used as training and test sets in a SemEval-2016 shared task competition. We propose a simple stance detection system that outperforms submissions from all 19 teams that participated in the shared task. Additionally, access to both stance and sentiment annotations allows us to explore several research questions. We show that while knowing the sentiment expressed by a tweet is beneficial for stance classification, it alone is not sufficient. Finally, we use additional unlabeled data through distant supervision techniques and word embeddings to further improve stance classification.
1403.5006
Ning Yan
Ning Yan, Sona Hasani, Abolfazl Asudeh, Chengkai Li
Generating Preview Tables for Entity Graphs
This is the camera-ready version of a SIGMOD16 paper. There might be tiny differences in layout, spacing and linebreaking, compared with the version in the SIGMOD16 proceedings, since we must submit TeX files and use arXiv to compile the files
null
10.1145/2882903.2915221
null
cs.DB cs.IR
http://creativecommons.org/licenses/by/4.0/
Users are tapping into massive, heterogeneous entity graphs for many applications. It is challenging to select entity graphs for a particular need, given abundant datasets from many sources and the oftentimes scarce information for them. We propose methods to produce preview tables for compact presentation of important entity types and relationships in entity graphs. The preview tables assist users in attaining a quick and rough preview of the data. They can be shown in a limited display space for a user to browse and explore, before she decides to spend time and resources to fetch and investigate the complete dataset. We formulate several optimization problems that look for previews with the highest scores according to intuitive goodness measures, under various constraints on preview size and distance between preview tables. The optimization problem under distance constraint is NP-hard. We design a dynamic-programming algorithm and an Apriori-style algorithm for finding optimal previews. Results from experiments, comparison with related work and user studies demonstrated the scoring measures' accuracy and the discovery algorithms' efficiency.
[ { "version": "v1", "created": "Thu, 20 Mar 2014 00:21:37 GMT" }, { "version": "v2", "created": "Wed, 4 May 2016 04:40:31 GMT" } ]
2016-05-05T00:00:00
[ [ "Yan", "Ning", "" ], [ "Hasani", "Sona", "" ], [ "Asudeh", "Abolfazl", "" ], [ "Li", "Chengkai", "" ] ]
TITLE: Generating Preview Tables for Entity Graphs ABSTRACT: Users are tapping into massive, heterogeneous entity graphs for many applications. It is challenging to select entity graphs for a particular need, given abundant datasets from many sources and the oftentimes scarce information for them. We propose methods to produce preview tables for compact presentation of important entity types and relationships in entity graphs. The preview tables assist users in attaining a quick and rough preview of the data. They can be shown in a limited display space for a user to browse and explore, before she decides to spend time and resources to fetch and investigate the complete dataset. We formulate several optimization problems that look for previews with the highest scores according to intuitive goodness measures, under various constraints on preview size and distance between preview tables. The optimization problem under distance constraint is NP-hard. We design a dynamic-programming algorithm and an Apriori-style algorithm for finding optimal previews. Results from experiments, comparison with related work and user studies demonstrated the scoring measures' accuracy and the discovery algorithms' efficiency.
1605.01101
Sourya Roy
Avisek Lahiri, Sourya Roy, Anirban Santara, Pabitra Mitra, Prabir Kumar Biswas
WEPSAM: Weakly Pre-Learnt Saliency Model
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Visual saliency detection tries to mimic human vision psychology which concentrates on sparse, important areas in natural image. Saliency prediction research has been traditionally based on low level features such as contrast, edge, etc. Recent thrust in saliency prediction research is to learn high level semantics using ground truth eye fixation datasets. In this paper we present, WEPSAM : Weakly Pre-Learnt Saliency Model as a pioneering effort of using domain specific pre-learing on ImageNet for saliency prediction using a light weight CNN architecture. The paper proposes a two step hierarchical learning, in which the first step is to develop a framework for weakly pre-training on a large scale dataset such as ImageNet which is void of human eye fixation maps. The second step refines the pre-trained model on a limited set of ground truth fixations. Analysis of loss on iSUN and SALICON datasets reveal that pre-trained network converges much faster compared to randomly initialized network. WEPSAM also outperforms some recent state-of-the-art saliency prediction models on the challenging MIT300 dataset.
[ { "version": "v1", "created": "Tue, 3 May 2016 21:47:33 GMT" } ]
2016-05-05T00:00:00
[ [ "Lahiri", "Avisek", "" ], [ "Roy", "Sourya", "" ], [ "Santara", "Anirban", "" ], [ "Mitra", "Pabitra", "" ], [ "Biswas", "Prabir Kumar", "" ] ]
TITLE: WEPSAM: Weakly Pre-Learnt Saliency Model ABSTRACT: Visual saliency detection tries to mimic human vision psychology which concentrates on sparse, important areas in natural image. Saliency prediction research has been traditionally based on low level features such as contrast, edge, etc. Recent thrust in saliency prediction research is to learn high level semantics using ground truth eye fixation datasets. In this paper we present, WEPSAM : Weakly Pre-Learnt Saliency Model as a pioneering effort of using domain specific pre-learing on ImageNet for saliency prediction using a light weight CNN architecture. The paper proposes a two step hierarchical learning, in which the first step is to develop a framework for weakly pre-training on a large scale dataset such as ImageNet which is void of human eye fixation maps. The second step refines the pre-trained model on a limited set of ground truth fixations. Analysis of loss on iSUN and SALICON datasets reveal that pre-trained network converges much faster compared to randomly initialized network. WEPSAM also outperforms some recent state-of-the-art saliency prediction models on the challenging MIT300 dataset.
1605.01130
Yaming Wang
Yaming Wang, Jonghyun Choi, Vlad I. Morariu, Larry S. Davis
Mining Discriminative Triplets of Patches for Fine-Grained Classification
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Fine-grained classification involves distinguishing between similar sub-categories based on subtle differences in highly localized regions; therefore, accurate localization of discriminative regions remains a major challenge. We describe a patch-based framework to address this problem. We introduce triplets of patches with geometric constraints to improve the accuracy of patch localization, and automatically mine discriminative geometrically-constrained triplets for classification. The resulting approach only requires object bounding boxes. Its effectiveness is demonstrated using four publicly available fine-grained datasets, on which it outperforms or achieves comparable performance to the state-of-the-art in classification.
[ { "version": "v1", "created": "Wed, 4 May 2016 02:34:18 GMT" } ]
2016-05-05T00:00:00
[ [ "Wang", "Yaming", "" ], [ "Choi", "Jonghyun", "" ], [ "Morariu", "Vlad I.", "" ], [ "Davis", "Larry S.", "" ] ]
TITLE: Mining Discriminative Triplets of Patches for Fine-Grained Classification ABSTRACT: Fine-grained classification involves distinguishing between similar sub-categories based on subtle differences in highly localized regions; therefore, accurate localization of discriminative regions remains a major challenge. We describe a patch-based framework to address this problem. We introduce triplets of patches with geometric constraints to improve the accuracy of patch localization, and automatically mine discriminative geometrically-constrained triplets for classification. The resulting approach only requires object bounding boxes. Its effectiveness is demonstrated using four publicly available fine-grained datasets, on which it outperforms or achieves comparable performance to the state-of-the-art in classification.
1605.01156
Yunjie Liu
Yunjie Liu, Evan Racah, Prabhat, Joaquin Correa, Amir Khosrowshahi, David Lavers, Kenneth Kunkel, Michael Wehner, William Collins
Application of Deep Convolutional Neural Networks for Detecting Extreme Weather in Climate Datasets
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Detecting extreme events in large datasets is a major challenge in climate science research. Current algorithms for extreme event detection are build upon human expertise in defining events based on subjective thresholds of relevant physical variables. Often, multiple competing methods produce vastly different results on the same dataset. Accurate characterization of extreme events in climate simulations and observational data archives is critical for understanding the trends and potential impacts of such events in a climate change content. This study presents the first application of Deep Learning techniques as alternative methodology for climate extreme events detection. Deep neural networks are able to learn high-level representations of a broad class of patterns from labeled data. In this work, we developed deep Convolutional Neural Network (CNN) classification system and demonstrated the usefulness of Deep Learning technique for tackling climate pattern detection problems. Coupled with Bayesian based hyper-parameter optimization scheme, our deep CNN system achieves 89\%-99\% of accuracy in detecting extreme events (Tropical Cyclones, Atmospheric Rivers and Weather Fronts
[ { "version": "v1", "created": "Wed, 4 May 2016 06:38:19 GMT" } ]
2016-05-05T00:00:00
[ [ "Liu", "Yunjie", "" ], [ "Racah", "Evan", "" ], [ "Prabhat", "", "" ], [ "Correa", "Joaquin", "" ], [ "Khosrowshahi", "Amir", "" ], [ "Lavers", "David", "" ], [ "Kunkel", "Kenneth", "" ], [ "Wehner", "Michael", "" ], [ "Collins", "William", "" ] ]
TITLE: Application of Deep Convolutional Neural Networks for Detecting Extreme Weather in Climate Datasets ABSTRACT: Detecting extreme events in large datasets is a major challenge in climate science research. Current algorithms for extreme event detection are build upon human expertise in defining events based on subjective thresholds of relevant physical variables. Often, multiple competing methods produce vastly different results on the same dataset. Accurate characterization of extreme events in climate simulations and observational data archives is critical for understanding the trends and potential impacts of such events in a climate change content. This study presents the first application of Deep Learning techniques as alternative methodology for climate extreme events detection. Deep neural networks are able to learn high-level representations of a broad class of patterns from labeled data. In this work, we developed deep Convolutional Neural Network (CNN) classification system and demonstrated the usefulness of Deep Learning technique for tackling climate pattern detection problems. Coupled with Bayesian based hyper-parameter optimization scheme, our deep CNN system achieves 89\%-99\% of accuracy in detecting extreme events (Tropical Cyclones, Atmospheric Rivers and Weather Fronts
1605.01189
Sheraz Ahmed Dr.
Sheraz Ahmed, Muhammad Imran Malik, Muhammad Zeshan Afzal, Koichi Kise, Masakazu Iwamura, Andreas Dengel, Marcus Liwicki
A Generic Method for Automatic Ground Truth Generation of Camera-captured Documents
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
The contribution of this paper is fourfold. The first contribution is a novel, generic method for automatic ground truth generation of camera-captured document images (books, magazines, articles, invoices, etc.). It enables us to build large-scale (i.e., millions of images) labeled camera-captured/scanned documents datasets, without any human intervention. The method is generic, language independent and can be used for generation of labeled documents datasets (both scanned and cameracaptured) in any cursive and non-cursive language, e.g., English, Russian, Arabic, Urdu, etc. To assess the effectiveness of the presented method, two different datasets in English and Russian are generated using the presented method. Evaluation of samples from the two datasets shows that 99:98% of the images were correctly labeled. The second contribution is a large dataset (called C3Wi) of camera-captured characters and words images, comprising 1 million word images (10 million character images), captured in a real camera-based acquisition. This dataset can be used for training as well as testing of character recognition systems on camera-captured documents. The third contribution is a novel method for the recognition of cameracaptured document images. The proposed method is based on Long Short-Term Memory and outperforms the state-of-the-art methods for camera based OCRs. As a fourth contribution, various benchmark tests are performed to uncover the behavior of commercial (ABBYY), open source (Tesseract), and the presented camera-based OCR using the presented C3Wi dataset. Evaluation results reveal that the existing OCRs, which already get very high accuracies on scanned documents, have limited performance on camera-captured document images; where ABBYY has an accuracy of 75%, Tesseract an accuracy of 50.22%, while the presented character recognition system has an accuracy of 95.10%.
[ { "version": "v1", "created": "Wed, 4 May 2016 09:25:04 GMT" } ]
2016-05-05T00:00:00
[ [ "Ahmed", "Sheraz", "" ], [ "Malik", "Muhammad Imran", "" ], [ "Afzal", "Muhammad Zeshan", "" ], [ "Kise", "Koichi", "" ], [ "Iwamura", "Masakazu", "" ], [ "Dengel", "Andreas", "" ], [ "Liwicki", "Marcus", "" ] ]
TITLE: A Generic Method for Automatic Ground Truth Generation of Camera-captured Documents ABSTRACT: The contribution of this paper is fourfold. The first contribution is a novel, generic method for automatic ground truth generation of camera-captured document images (books, magazines, articles, invoices, etc.). It enables us to build large-scale (i.e., millions of images) labeled camera-captured/scanned documents datasets, without any human intervention. The method is generic, language independent and can be used for generation of labeled documents datasets (both scanned and cameracaptured) in any cursive and non-cursive language, e.g., English, Russian, Arabic, Urdu, etc. To assess the effectiveness of the presented method, two different datasets in English and Russian are generated using the presented method. Evaluation of samples from the two datasets shows that 99:98% of the images were correctly labeled. The second contribution is a large dataset (called C3Wi) of camera-captured characters and words images, comprising 1 million word images (10 million character images), captured in a real camera-based acquisition. This dataset can be used for training as well as testing of character recognition systems on camera-captured documents. The third contribution is a novel method for the recognition of cameracaptured document images. The proposed method is based on Long Short-Term Memory and outperforms the state-of-the-art methods for camera based OCRs. As a fourth contribution, various benchmark tests are performed to uncover the behavior of commercial (ABBYY), open source (Tesseract), and the presented camera-based OCR using the presented C3Wi dataset. Evaluation results reveal that the existing OCRs, which already get very high accuracies on scanned documents, have limited performance on camera-captured document images; where ABBYY has an accuracy of 75%, Tesseract an accuracy of 50.22%, while the presented character recognition system has an accuracy of 95.10%.
1605.01194
Sharmistha Jat
Lavanya Sita Tekumalla and Sharmistha
IISCNLP at SemEval-2016 Task 2: Interpretable STS with ILP based Multiple Chunk Aligner
SEMEVAL Workshop @ NAACL 2016
null
null
null
cs.CL stat.ML
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
Interpretable semantic textual similarity (iSTS) task adds a crucial explanatory layer to pairwise sentence similarity. We address various components of this task: chunk level semantic alignment along with assignment of similarity type and score for aligned chunks with a novel system presented in this paper. We propose an algorithm, iMATCH, for the alignment of multiple non-contiguous chunks based on Integer Linear Programming (ILP). Similarity type and score assignment for pairs of chunks is done using a supervised multiclass classification technique based on Random Forrest Classifier. Results show that our algorithm iMATCH has low execution time and outperforms most other participating systems in terms of alignment score. Of the three datasets, we are top ranked for answer- students dataset in terms of overall score and have top alignment score for headlines dataset in the gold chunks track.
[ { "version": "v1", "created": "Wed, 4 May 2016 09:36:49 GMT" } ]
2016-05-05T00:00:00
[ [ "Tekumalla", "Lavanya Sita", "" ], [ "Sharmistha", "", "" ] ]
TITLE: IISCNLP at SemEval-2016 Task 2: Interpretable STS with ILP based Multiple Chunk Aligner ABSTRACT: Interpretable semantic textual similarity (iSTS) task adds a crucial explanatory layer to pairwise sentence similarity. We address various components of this task: chunk level semantic alignment along with assignment of similarity type and score for aligned chunks with a novel system presented in this paper. We propose an algorithm, iMATCH, for the alignment of multiple non-contiguous chunks based on Integer Linear Programming (ILP). Similarity type and score assignment for pairs of chunks is done using a supervised multiclass classification technique based on Random Forrest Classifier. Results show that our algorithm iMATCH has low execution time and outperforms most other participating systems in terms of alignment score. Of the three datasets, we are top ranked for answer- students dataset in terms of overall score and have top alignment score for headlines dataset in the gold chunks track.
1605.01397
Noel Codella
David Gutman, Noel C. F. Codella, Emre Celebi, Brian Helba, Michael Marchetti, Nabin Mishra, Allan Halpern
Skin Lesion Analysis toward Melanoma Detection: A Challenge at the International Symposium on Biomedical Imaging (ISBI) 2016, hosted by the International Skin Imaging Collaboration (ISIC)
null
null
null
null
cs.CV
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
In this article, we describe the design and implementation of a publicly accessible dermatology image analysis benchmark challenge. The goal of the challenge is to sup- port research and development of algorithms for automated diagnosis of melanoma, a lethal form of skin cancer, from dermoscopic images. The challenge was divided into sub-challenges for each task involved in image analysis, including lesion segmentation, dermoscopic feature detection within a lesion, and classification of melanoma. Training data included 900 images. A separate test dataset of 379 images was provided to measure resultant performance of systems developed with the training data. Ground truth for both training and test sets was generated by a panel of dermoscopic experts. In total, there were 79 submissions from a group of 38 participants, making this the largest standardized and comparative study for melanoma diagnosis in dermoscopic images to date. While the official challenge duration and ranking of participants has concluded, the datasets remain available for further research and development.
[ { "version": "v1", "created": "Wed, 4 May 2016 19:49:17 GMT" } ]
2016-05-05T00:00:00
[ [ "Gutman", "David", "" ], [ "Codella", "Noel C. F.", "" ], [ "Celebi", "Emre", "" ], [ "Helba", "Brian", "" ], [ "Marchetti", "Michael", "" ], [ "Mishra", "Nabin", "" ], [ "Halpern", "Allan", "" ] ]
TITLE: Skin Lesion Analysis toward Melanoma Detection: A Challenge at the International Symposium on Biomedical Imaging (ISBI) 2016, hosted by the International Skin Imaging Collaboration (ISIC) ABSTRACT: In this article, we describe the design and implementation of a publicly accessible dermatology image analysis benchmark challenge. The goal of the challenge is to sup- port research and development of algorithms for automated diagnosis of melanoma, a lethal form of skin cancer, from dermoscopic images. The challenge was divided into sub-challenges for each task involved in image analysis, including lesion segmentation, dermoscopic feature detection within a lesion, and classification of melanoma. Training data included 900 images. A separate test dataset of 379 images was provided to measure resultant performance of systems developed with the training data. Ground truth for both training and test sets was generated by a panel of dermoscopic experts. In total, there were 79 submissions from a group of 38 participants, making this the largest standardized and comparative study for melanoma diagnosis in dermoscopic images to date. While the official challenge duration and ranking of participants has concluded, the datasets remain available for further research and development.