categories
string
doi
string
id
string
year
float64
venue
string
link
string
updated
string
published
string
title
string
abstract
string
authors
list
cs.RO cs.AI cs.LG
null
1612.05533
null
null
http://arxiv.org/pdf/1612.05533v3
2017-07-23T16:36:33Z
2016-12-16T16:15:26Z
Deep Reinforcement Learning with Successor Features for Navigation across Similar Environments
In this paper we consider the problem of robot navigation in simple maze-like environments where the robot has to rely on its onboard sensors to perform the navigation task. In particular, we are interested in solutions to this problem that do not require localization, mapping or planning. Additionally, we require that our solution can quickly adapt to new situations (e.g., changing navigation goals and environments). To meet these criteria we frame this problem as a sequence of related reinforcement learning tasks. We propose a successor feature based deep reinforcement learning algorithm that can learn to transfer knowledge from previously mastered navigation tasks to new problem instances. Our algorithm substantially decreases the required learning time after the first task instance has been solved, which makes it easily adaptable to changing environments. We validate our method in both simulated and real robot experiments with a Robotino and compare it to a set of baseline methods including classical planning-based navigation.
[ "Jingwei Zhang, Jost Tobias Springenberg, Joschka Boedecker, Wolfram\n Burgard", "['Jingwei Zhang' 'Jost Tobias Springenberg' 'Joschka Boedecker'\n 'Wolfram Burgard']" ]
cs.LG
null
1612.05627
null
null
http://arxiv.org/pdf/1612.05627v1
2016-12-13T00:54:03Z
2016-12-13T00:54:03Z
Models, networks and algorithmic complexity
I aim to show that models, classification or generating functions, invariances and datasets are algorithmically equivalent concepts once properly defined, and provide some concrete examples of them. I then show that a) neural networks (NNs) of different kinds can be seen to implement models, b) that perturbations of inputs and nodes in NNs trained to optimally implement simple models propagate strongly, c) that there is a framework in which recurrent, deep and shallow networks can be seen to fall into a descriptive power hierarchy in agreement with notions from the theory of recursive functions. The motivation for these definitions and following analysis lies in the context of cognitive neuroscience, and in particular in Ruffini (2016), where the concept of model is used extensively, as is the concept of algorithmic complexity.
[ "Giulio Ruffini", "['Giulio Ruffini']" ]
cs.AI cs.LG stat.ML
null
1612.05628
null
null
http://arxiv.org/pdf/1612.05628v5
2017-06-14T14:29:04Z
2016-12-16T20:49:35Z
An Alternative Softmax Operator for Reinforcement Learning
A softmax operator applied to a set of values acts somewhat like the maximization function and somewhat like an average. In sequential decision making, softmax is often used in settings where it is necessary to maximize utility but also to hedge against problems that arise from putting all of one's weight behind a single maximum utility decision. The Boltzmann softmax operator is the most commonly used softmax operator in this setting, but we show that this operator is prone to misbehavior. In this work, we study a differentiable softmax operator that, among other properties, is a non-expansion ensuring a convergent behavior in learning and planning. We introduce a variant of SARSA algorithm that, by utilizing the new operator, computes a Boltzmann policy with a state-dependent temperature parameter. We show that the algorithm is convergent and that it performs favorably in practice.
[ "['Kavosh Asadi' 'Michael L. Littman']", "Kavosh Asadi, Michael L. Littman" ]
cs.LG cs.AI cs.CL
null
1612.05688
null
null
http://arxiv.org/pdf/1612.05688v3
2017-11-13T05:52:42Z
2016-12-17T01:03:55Z
A User Simulator for Task-Completion Dialogues
Despite widespread interests in reinforcement-learning for task-oriented dialogue systems, several obstacles can frustrate research and development progress. First, reinforcement learners typically require interaction with the environment, so conventional dialogue corpora cannot be used directly. Second, each task presents specific challenges, requiring separate corpus of task-specific annotated data. Third, collecting and annotating human-machine or human-human conversations for task-oriented dialogues requires extensive domain knowledge. Because building an appropriate dataset can be both financially costly and time-consuming, one popular approach is to build a user simulator based upon a corpus of example dialogues. Then, one can train reinforcement learning agents in an online fashion as they interact with the simulator. Dialogue agents trained on these simulators can serve as an effective starting point. Once agents master the simulator, they may be deployed in a real environment to interact with humans, and continue to be trained online. To ease empirical algorithmic comparisons in dialogues, this paper introduces a new, publicly available simulation framework, where our simulator, designed for the movie-booking domain, leverages both rules and collected data. The simulator supports two tasks: movie ticket booking and movie seeking. Finally, we demonstrate several agents and detail the procedure to add and test your own agent in the proposed framework.
[ "['Xiujun Li' 'Zachary C. Lipton' 'Bhuwan Dhingra' 'Lihong Li'\n 'Jianfeng Gao' 'Yun-Nung Chen']", "Xiujun Li, Zachary C. Lipton, Bhuwan Dhingra, Lihong Li, Jianfeng Gao,\n Yun-Nung Chen" ]
quant-ph cs.AI cs.LG cs.NE math.OC
null
1612.05695
null
null
http://arxiv.org/pdf/1612.05695v3
2019-01-03T20:49:47Z
2016-12-17T02:33:41Z
Reinforcement Learning Using Quantum Boltzmann Machines
We investigate whether quantum annealers with select chip layouts can outperform classical computers in reinforcement learning tasks. We associate a transverse field Ising spin Hamiltonian with a layout of qubits similar to that of a deep Boltzmann machine (DBM) and use simulated quantum annealing (SQA) to numerically simulate quantum sampling from this system. We design a reinforcement learning algorithm in which the set of visible nodes representing the states and actions of an optimal policy are the first and last layers of the deep network. In absence of a transverse field, our simulations show that DBMs are trained more effectively than restricted Boltzmann machines (RBM) with the same number of nodes. We then develop a framework for training the network as a quantum Boltzmann machine (QBM) in the presence of a significant transverse field for reinforcement learning. This method also outperforms the reinforcement learning method that uses RBMs.
[ "Daniel Crawford, Anna Levit, Navid Ghadermarzy, Jaspreet S. Oberoi,\n Pooya Ronagh", "['Daniel Crawford' 'Anna Levit' 'Navid Ghadermarzy' 'Jaspreet S. Oberoi'\n 'Pooya Ronagh']" ]
math.OC cs.LG stat.ML
null
1612.05708
null
null
http://arxiv.org/pdf/1612.05708v1
2016-12-17T05:26:46Z
2016-12-17T05:26:46Z
Mutual information for fitting deep nonlinear models
Deep nonlinear models pose a challenge for fitting parameters due to lack of knowledge of the hidden layer and the potentially non-affine relation of the initial and observed layers. In the present work we investigate the use of information theoretic measures such as mutual information and Kullback-Leibler (KL) divergence as objective functions for fitting such models without knowledge of the hidden layer. We investigate one model as a proof of concept and one application of cogntive performance. We further investigate the use of optimizers with these methods. Mutual information is largely successful as an objective, depending on the parameters. KL divergence is found to be similarly succesful, given some knowledge of the statistics of the hidden layer.
[ "['Jacob S. Hunter' 'Nathan O. Hodas']", "Jacob S. Hunter (1) and Nathan O. Hodas (1) ((1) Pacific Northwest\n National Laboratory)" ]
cs.IR cs.AI cs.LG
null
1612.05729
null
null
http://arxiv.org/pdf/1612.05729v1
2016-12-17T10:50:41Z
2016-12-17T10:50:41Z
Exploiting sparsity to build efficient kernel based collaborative filtering for top-N item recommendation
The increasing availability of implicit feedback datasets has raised the interest in developing effective collaborative filtering techniques able to deal asymmetrically with unambiguous positive feedback and ambiguous negative feedback. In this paper, we propose a principled kernel-based collaborative filtering method for top-N item recommendation with implicit feedback. We present an efficient implementation using the linear kernel, and we show how to generalize it to kernels of the dot product family preserving the efficiency. We also investigate on the elements which influence the sparsity of a standard cosine kernel. This analysis shows that the sparsity of the kernel strongly depends on the properties of the dataset, in particular on the long tail distribution. We compare our method with state-of-the-art algorithms achieving good results both in terms of efficiency and effectiveness.
[ "Mirko Polato and Fabio Aiolli", "['Mirko Polato' 'Fabio Aiolli']" ]
stat.ML cs.LG
null
1612.0573
null
null
null
null
null
Towards Wide Learning: Experiments in Healthcare
In this paper, a Wide Learning architecture is proposed that attempts to automate the feature engineering portion of the machine learning (ML) pipeline. Feature engineering is widely considered as the most time consuming and expert knowledge demanding portion of any ML task. The proposed feature recommendation approach is tested on 3 healthcare datasets: a) PhysioNet Challenge 2016 dataset of phonocardiogram (PCG) signals, b) MIMIC II blood pressure classification dataset of photoplethysmogram (PPG) signals and c) an emotion classification dataset of PPG signals. While the proposed method beats the state of the art techniques for 2nd and 3rd dataset, it reaches 94.38% of the accuracy level of the winner of PhysioNet Challenge 2016. In all cases, the effort to reach a satisfactory performance was drastically less (a few days) than manual feature engineering.
[ "Snehasis Banerjee, Tanushyam Chattopadhyay, Swagata Biswas, Rohan\n Banerjee, Anirban Dutta Choudhury, Arpan Pal and Utpal Garain" ]
null
null
1612.05730
null
null
http://arxiv.org/pdf/1612.05730v2
2016-12-21T13:53:15Z
2016-12-17T11:00:49Z
Towards Wide Learning: Experiments in Healthcare
In this paper, a Wide Learning architecture is proposed that attempts to automate the feature engineering portion of the machine learning (ML) pipeline. Feature engineering is widely considered as the most time consuming and expert knowledge demanding portion of any ML task. The proposed feature recommendation approach is tested on 3 healthcare datasets: a) PhysioNet Challenge 2016 dataset of phonocardiogram (PCG) signals, b) MIMIC II blood pressure classification dataset of photoplethysmogram (PPG) signals and c) an emotion classification dataset of PPG signals. While the proposed method beats the state of the art techniques for 2nd and 3rd dataset, it reaches 94.38% of the accuracy level of the winner of PhysioNet Challenge 2016. In all cases, the effort to reach a satisfactory performance was drastically less (a few days) than manual feature engineering.
[ "['Snehasis Banerjee' 'Tanushyam Chattopadhyay' 'Swagata Biswas'\n 'Rohan Banerjee' 'Anirban Dutta Choudhury' 'Arpan Pal' 'Utpal Garain']" ]
cs.LG stat.ML
null
1612.0574
null
null
null
null
null
Machine Learning, Linear and Bayesian Models for Logistic Regression in Failure Detection Problems
In this work, we study the use of logistic regression in manufacturing failures detection. As a data set for the analysis, we used the data from Kaggle competition Bosch Production Line Performance. We considered the use of machine learning, linear and Bayesian models. For machine learning approach, we analyzed XGBoost tree based classifier to obtain high scored classification. Using the generalized linear model for logistic regression makes it possible to analyze the influence of the factors under study. The Bayesian approach for logistic regression gives the statistical distribution for the parameters of the model. It can be useful in the probabilistic analysis, e.g. risk assessment.
[ "B. Pavlyshenko" ]
null
null
1612.05740
null
null
http://arxiv.org/pdf/1612.05740v1
2016-12-17T11:57:45Z
2016-12-17T11:57:45Z
Machine Learning, Linear and Bayesian Models for Logistic Regression in Failure Detection Problems
In this work, we study the use of logistic regression in manufacturing failures detection. As a data set for the analysis, we used the data from Kaggle competition Bosch Production Line Performance. We considered the use of machine learning, linear and Bayesian models. For machine learning approach, we analyzed XGBoost tree based classifier to obtain high scored classification. Using the generalized linear model for logistic regression makes it possible to analyze the influence of the factors under study. The Bayesian approach for logistic regression gives the statistical distribution for the parameters of the model. It can be useful in the probabilistic analysis, e.g. risk assessment.
[ "['B. Pavlyshenko']" ]
cs.CV cs.LG
null
1612.05753
null
null
http://arxiv.org/pdf/1612.05753v2
2017-02-18T21:23:14Z
2016-12-17T13:29:59Z
Learning to predict where to look in interactive environments using deep recurrent q-learning
Bottom-Up (BU) saliency models do not perform well in complex interactive environments where humans are actively engaged in tasks (e.g., sandwich making and playing the video games). In this paper, we leverage Reinforcement Learning (RL) to highlight task-relevant locations of input frames. We propose a soft attention mechanism combined with the Deep Q-Network (DQN) model to teach an RL agent how to play a game and where to look by focusing on the most pertinent parts of its visual input. Our evaluations on several Atari 2600 games show that the soft attention based model could predict fixation locations significantly better than bottom-up models such as Itti-Kochs saliency and Graph-Based Visual Saliency (GBVS) models.
[ "['Sajad Mousavi' 'Michael Schukat' 'Enda Howley' 'Ali Borji'\n 'Nasser Mozayani']", "Sajad Mousavi, Michael Schukat, Enda Howley, Ali Borji and Nasser\n Mozayani" ]
cs.LG
null
1612.05794
null
null
http://arxiv.org/pdf/1612.05794v1
2016-12-17T17:01:08Z
2016-12-17T17:01:08Z
A new recurrent neural network based predictive model for Faecal Calprotectin analysis: A retrospective study
Faecal Calprotectin (FC) is a surrogate marker for intestinal inflammation, termed Inflammatory Bowel Disease (IBD), but not for cancer. In this retrospective study of 804 patients, an enhanced benchmark predictive model for analyzing FC is developed, based on a novel state-of-the-art Echo State Network (ESN), an advanced dynamic recurrent neural network which implements a biologically plausible architecture, and a supervised learning mechanism. The proposed machine learning driven predictive model is benchmarked against a conventional logistic regression model, demonstrating statistically significant performance improvements.
[ "Zeeshan Khawar Malik, Zain U. Hussain, Ziad Kobti, Charlie W. Lees,\n Newton Howard and Amir Hussain", "['Zeeshan Khawar Malik' 'Zain U. Hussain' 'Ziad Kobti' 'Charlie W. Lees'\n 'Newton Howard' 'Amir Hussain']" ]
cs.CV cs.LG cs.NE
null
1612.05836
null
null
http://arxiv.org/pdf/1612.05836v1
2016-12-17T23:33:37Z
2016-12-17T23:33:37Z
EgoTransfer: Transferring Motion Across Egocentric and Exocentric Domains using Deep Neural Networks
Mirror neurons have been observed in the primary motor cortex of primate species, in particular in humans and monkeys. A mirror neuron fires when a person performs a certain action, and also when he observes the same action being performed by another person. A crucial step towards building fully autonomous intelligent systems with human-like learning abilities is the capability in modeling the mirror neuron. On one hand, the abundance of egocentric cameras in the past few years has offered the opportunity to study a lot of vision problems from the first-person perspective. A great deal of interesting research has been done during the past few years, trying to explore various computer vision tasks from the perspective of the self. On the other hand, videos recorded by traditional static cameras, capture humans performing different actions from an exocentric third-person perspective. In this work, we take the first step towards relating motion information across these two perspectives. We train models that predict motion in an egocentric view, by observing it from an exocentric view, and vice versa. This allows models to predict how an egocentric motion would look like from outside. To do so, we train linear and nonlinear models and evaluate their performance in terms of retrieving the egocentric (exocentric) motion features, while having access to an exocentric (egocentric) motion feature. Our experimental results demonstrate that motion information can be successfully transferred across the two views.
[ "Shervin Ardeshir, Krishna Regmi, and Ali Borji", "['Shervin Ardeshir' 'Krishna Regmi' 'Ali Borji']" ]
cs.LG stat.ML
null
1612.05888
null
null
http://arxiv.org/pdf/1612.05888v2
2017-06-26T10:48:23Z
2016-12-18T10:21:20Z
Building Diversified Multiple Trees for Classification in High Dimensional Noisy Biomedical Data
It is common that a trained classification model is applied to the operating data that is deviated from the training data because of noise. This paper demonstrates that an ensemble classifier, Diversified Multiple Tree (DMT), is more robust in classifying noisy data than other widely used ensemble methods. DMT is tested on three real world biomedical data sets from different laboratories in comparison with four benchmark ensemble classifiers. Experimental results show that DMT is significantly more accurate than other benchmark ensemble classifiers on noisy test data. We also discuss a limitation of DMT and its possible variations.
[ "['Jiuyong Li' 'Lin Liu' 'Jixue Liu' 'Ryan Green']", "Jiuyong Li, Lin Liu, Jixue Liu and Ryan Green" ]
cs.CV cs.LG
null
1612.05968
null
null
http://arxiv.org/pdf/1612.05968v1
2016-12-18T18:31:11Z
2016-12-18T18:31:11Z
Deep Multi-instance Networks with Sparse Label Assignment for Whole Mammogram Classification
Mammogram classification is directly related to computer-aided diagnosis of breast cancer. Traditional methods requires great effort to annotate the training data by costly manual labeling and specialized computational models to detect these annotations during test. Inspired by the success of using deep convolutional features for natural image analysis and multi-instance learning for labeling a set of instances/patches, we propose end-to-end trained deep multi-instance networks for mass classification based on whole mammogram without the aforementioned costly need to annotate the training data. We explore three different schemes to construct deep multi-instance networks for whole mammogram classification. Experimental results on the INbreast dataset demonstrate the robustness of proposed deep networks compared to previous work using segmentation and detection annotations in the training.
[ "Wentao Zhu, Qi Lou, Yeeleng Scott Vang, Xiaohui Xie", "['Wentao Zhu' 'Qi Lou' 'Yeeleng Scott Vang' 'Xiaohui Xie']" ]
cs.CV cs.LG
null
1612.0597
null
null
null
null
null
Adversarial Deep Structural Networks for Mammographic Mass Segmentation
Mass segmentation is an important task in mammogram analysis, providing effective morphological features and regions of interest (ROI) for mass detection and classification. Inspired by the success of using deep convolutional features for natural image analysis and conditional random fields (CRF) for structural learning, we propose an end-to-end network for mammographic mass segmentation. The network employs a fully convolutional network (FCN) to model potential function, followed by a CRF to perform structural learning. Because the mass distribution varies greatly with pixel position, the FCN is combined with position priori for the task. Due to the small size of mammogram datasets, we use adversarial training to control over-fitting. Four models with different convolutional kernels are further fused to improve the segmentation results. Experimental results on two public datasets, INbreast and DDSM-BCRP, show that our end-to-end network combined with adversarial training achieves the-state-of-the-art results.
[ "Wentao Zhu, Xiang Xiang, Trac D. Tran, Xiaohui Xie" ]
null
null
1612.05970
null
null
http://arxiv.org/pdf/1612.05970v2
2017-06-09T21:32:38Z
2016-12-18T18:40:21Z
Adversarial Deep Structural Networks for Mammographic Mass Segmentation
Mass segmentation is an important task in mammogram analysis, providing effective morphological features and regions of interest (ROI) for mass detection and classification. Inspired by the success of using deep convolutional features for natural image analysis and conditional random fields (CRF) for structural learning, we propose an end-to-end network for mammographic mass segmentation. The network employs a fully convolutional network (FCN) to model potential function, followed by a CRF to perform structural learning. Because the mass distribution varies greatly with pixel position, the FCN is combined with position priori for the task. Due to the small size of mammogram datasets, we use adversarial training to control over-fitting. Four models with different convolutional kernels are further fused to improve the segmentation results. Experimental results on two public datasets, INbreast and DDSM-BCRP, show that our end-to-end network combined with adversarial training achieves the-state-of-the-art results.
[ "['Wentao Zhu' 'Xiang Xiang' 'Trac D. Tran' 'Xiaohui Xie']" ]
cs.AR cs.CR cs.LG cs.NE
10.1109/TCSI.2017.2698019
1612.05974
null
null
http://arxiv.org/abs/1612.05974v3
2017-04-23T17:39:09Z
2016-12-18T19:20:42Z
An IoT Endpoint System-on-Chip for Secure and Energy-Efficient Near-Sensor Analytics
Near-sensor data analytics is a promising direction for IoT endpoints, as it minimizes energy spent on communication and reduces network load - but it also poses security concerns, as valuable data is stored or sent over the network at various stages of the analytics pipeline. Using encryption to protect sensitive data at the boundary of the on-chip analytics engine is a way to address data security issues. To cope with the combined workload of analytics and encryption in a tight power envelope, we propose Fulmine, a System-on-Chip based on a tightly-coupled multi-core cluster augmented with specialized blocks for compute-intensive data processing and encryption functions, supporting software programmability for regular computing tasks. The Fulmine SoC, fabricated in 65nm technology, consumes less than 20mW on average at 0.8V achieving an efficiency of up to 70pJ/B in encryption, 50pJ/px in convolution, or up to 25MIPS/mW in software. As a strong argument for real-life flexible application of our platform, we show experimental results for three secure analytics use cases: secure autonomous aerial surveillance with a state-of-the-art deep CNN consuming 3.16pJ per equivalent RISC op; local CNN-based face detection with secured remote recognition in 5.74pJ/op; and seizure detection with encrypted data collection from EEG within 12.7pJ/op.
[ "Francesco Conti, Robert Schilling, Pasquale Davide Schiavone, Antonio\n Pullini, Davide Rossi, Frank Kagan G\\\"urkaynak, Michael Muehlberghuber,\n Michael Gautschi, Igor Loi, Germain Haugou, Stefan Mangard, Luca Benini", "['Francesco Conti' 'Robert Schilling' 'Pasquale Davide Schiavone'\n 'Antonio Pullini' 'Davide Rossi' 'Frank Kagan Gürkaynak'\n 'Michael Muehlberghuber' 'Michael Gautschi' 'Igor Loi' 'Germain Haugou'\n 'Stefan Mangard' 'Luca Benini']" ]
cs.AI cs.LG stat.ML
null
1612.06
null
null
null
null
null
Sample-efficient Deep Reinforcement Learning for Dialog Control
Representing a dialog policy as a recurrent neural network (RNN) is attractive because it handles partial observability, infers a latent representation of state, and can be optimized with supervised learning (SL) or reinforcement learning (RL). For RL, a policy gradient approach is natural, but is sample inefficient. In this paper, we present 3 methods for reducing the number of dialogs required to optimize an RNN-based dialog policy with RL. The key idea is to maintain a second RNN which predicts the value of the current policy, and to apply experience replay to both networks. On two tasks, these methods reduce the number of dialogs/episodes required by about a third, vs. standard policy gradient methods.
[ "Kavosh Asadi, Jason D. Williams" ]
null
null
1612.06000
null
null
http://arxiv.org/pdf/1612.06000v1
2016-12-18T21:51:10Z
2016-12-18T21:51:10Z
Sample-efficient Deep Reinforcement Learning for Dialog Control
Representing a dialog policy as a recurrent neural network (RNN) is attractive because it handles partial observability, infers a latent representation of state, and can be optimized with supervised learning (SL) or reinforcement learning (RL). For RL, a policy gradient approach is natural, but is sample inefficient. In this paper, we present 3 methods for reducing the number of dialogs required to optimize an RNN-based dialog policy with RL. The key idea is to maintain a second RNN which predicts the value of the current policy, and to apply experience replay to both networks. On two tasks, these methods reduce the number of dialogs/episodes required by about a third, vs. standard policy gradient methods.
[ "['Kavosh Asadi' 'Jason D. Williams']" ]
cs.LG stat.ML
null
1612.06003
null
null
http://arxiv.org/pdf/1612.06003v2
2018-09-08T12:38:31Z
2016-12-18T22:14:36Z
Inexact Proximal Gradient Methods for Non-convex and Non-smooth Optimization
In machine learning research, the proximal gradient methods are popular for solving various optimization problems with non-smooth regularization. Inexact proximal gradient methods are extremely important when exactly solving the proximal operator is time-consuming, or the proximal operator does not have an analytic solution. However, existing inexact proximal gradient methods only consider convex problems. The knowledge of inexact proximal gradient methods in the non-convex setting is very limited. % Moreover, for some machine learning models, there is still no proposed solver for exactly solving the proximal operator. To address this challenge, in this paper, we first propose three inexact proximal gradient algorithms, including the basic version and Nesterov's accelerated version. After that, we provide the theoretical analysis to the basic and Nesterov's accelerated versions. The theoretical results show that our inexact proximal gradient algorithms can have the same convergence rates as the ones of exact proximal gradient algorithms in the non-convex setting. Finally, we show the applications of our inexact proximal gradient algorithms on three representative non-convex learning problems. All experimental results confirm the superiority of our new inexact proximal gradient algorithms.
[ "Bin Gu and De Wang and Zhouyuan Huo and Heng Huang", "['Bin Gu' 'De Wang' 'Zhouyuan Huo' 'Heng Huang']" ]
cs.LG cs.AI
null
1612.06018
null
null
http://arxiv.org/pdf/1612.06018v2
2017-07-26T18:53:51Z
2016-12-19T01:09:23Z
Self-Correcting Models for Model-Based Reinforcement Learning
When an agent cannot represent a perfectly accurate model of its environment's dynamics, model-based reinforcement learning (MBRL) can fail catastrophically. Planning involves composing the predictions of the model; when flawed predictions are composed, even minor errors can compound and render the model useless for planning. Hallucinated Replay (Talvitie 2014) trains the model to "correct" itself when it produces errors, substantially improving MBRL with flawed models. This paper theoretically analyzes this approach, illuminates settings in which it is likely to be effective or ineffective, and presents a novel error bound, showing that a model's ability to self-correct is more tightly related to MBRL performance than one-step prediction error. These results inspire an MBRL algorithm for deterministic MDPs with performance guarantees that are robust to model class limitations.
[ "Erik Talvitie", "['Erik Talvitie']" ]
cs.LG
null
1612.06052
null
null
http://arxiv.org/pdf/1612.06052v2
2017-08-17T06:56:17Z
2016-12-19T05:54:18Z
Quantization and Training of Low Bit-Width Convolutional Neural Networks for Object Detection
We present LBW-Net, an efficient optimization based method for quantization and training of the low bit-width convolutional neural networks (CNNs). Specifically, we quantize the weights to zero or powers of two by minimizing the Euclidean distance between full-precision weights and quantized weights during backpropagation. We characterize the combinatorial nature of the low bit-width quantization problem. For 2-bit (ternary) CNNs, the quantization of $N$ weights can be done by an exact formula in $O(N\log N)$ complexity. When the bit-width is three and above, we further propose a semi-analytical thresholding scheme with a single free parameter for quantization that is computationally inexpensive. The free parameter is further determined by network retraining and object detection tests. LBW-Net has several desirable advantages over full-precision CNNs, including considerable memory savings, energy efficiency, and faster deployment. Our experiments on PASCAL VOC dataset show that compared with its 32-bit floating-point counterpart, the performance of the 6-bit LBW-Net is nearly lossless in the object detection tasks, and can even do better in some real world visual scenes, while empirically enjoying more than 4$\times$ faster deployment.
[ "['Penghang Yin' 'Shuai Zhang' 'Yingyong Qi' 'Jack Xin']", "Penghang Yin, Shuai Zhang, Yingyong Qi, Jack Xin" ]
cs.CV cs.LG
null
1612.0607
null
null
null
null
null
On Random Weights for Texture Generation in One Layer Neural Networks
Recent work in the literature has shown experimentally that one can use the lower layers of a trained convolutional neural network (CNN) to model natural textures. More interestingly, it has also been experimentally shown that only one layer with random filters can also model textures although with less variability. In this paper we ask the question as to why one layer CNNs with random filters are so effective in generating textures? We theoretically show that one layer convolutional architectures (without a non-linearity) paired with the an energy function used in previous literature, can in fact preserve and modulate frequency coefficients in a manner so that random weights and pretrained weights will generate the same type of images. Based on the results of this analysis we question whether similar properties hold in the case where one uses one convolution layer with a non-linearity. We show that in the case of ReLu non-linearity there are situations where only one input will give the minimum possible energy whereas in the case of no nonlinearity, there are always infinite solutions that will give the minimum possible energy. Thus we can show that in certain situations adding a ReLu non-linearity generates less variable images.
[ "Mihir Mongia and Kundan Kumar and Akram Erraqabi and Yoshua Bengio" ]
null
null
1612.06070
null
null
http://arxiv.org/pdf/1612.06070v1
2016-12-19T08:21:04Z
2016-12-19T08:21:04Z
On Random Weights for Texture Generation in One Layer Neural Networks
Recent work in the literature has shown experimentally that one can use the lower layers of a trained convolutional neural network (CNN) to model natural textures. More interestingly, it has also been experimentally shown that only one layer with random filters can also model textures although with less variability. In this paper we ask the question as to why one layer CNNs with random filters are so effective in generating textures? We theoretically show that one layer convolutional architectures (without a non-linearity) paired with the an energy function used in previous literature, can in fact preserve and modulate frequency coefficients in a manner so that random weights and pretrained weights will generate the same type of images. Based on the results of this analysis we question whether similar properties hold in the case where one uses one convolution layer with a non-linearity. We show that in the case of ReLu non-linearity there are situations where only one input will give the minimum possible energy whereas in the case of no nonlinearity, there are always infinite solutions that will give the minimum possible energy. Thus we can show that in certain situations adding a ReLu non-linearity generates less variable images.
[ "['Mihir Mongia' 'Kundan Kumar' 'Akram Erraqabi' 'Yoshua Bengio']" ]
stat.ML cs.LG
null
1612.06083
null
null
http://arxiv.org/pdf/1612.06083v1
2016-12-19T09:08:59Z
2016-12-19T09:08:59Z
Hierarchical Partitioning of the Output Space in Multi-label Data
Hierarchy Of Multi-label classifiers (HOMER) is a multi-label learning algorithm that breaks the initial learning task to several, easier sub-tasks by first constructing a hierarchy of labels from a given label set and secondly employing a given base multi-label classifier (MLC) to the resulting sub-problems. The primary goal is to effectively address class imbalance and scalability issues that often arise in real-world multi-label classification problems. In this work, we present the general setup for a HOMER model and a simple extension of the algorithm that is suited for MLCs that output rankings. Furthermore, we provide a detailed analysis of the properties of the algorithm, both from an aspect of effectiveness and computational complexity. A secondary contribution involves the presentation of a balanced variant of the k means algorithm, which serves in the first step of the label hierarchy construction. We conduct extensive experiments on six real-world datasets, studying empirically HOMER's parameters and providing examples of instantiations of the algorithm with different clustering approaches and MLCs, The empirical results demonstrate a significant improvement over the given base MLC.
[ "Yannis Papanikolaou, Ioannis Katakis, Grigorios Tsoumakas", "['Yannis Papanikolaou' 'Ioannis Katakis' 'Grigorios Tsoumakas']" ]
cs.NE cs.CL cs.LG
null
1612.06212
null
null
http://arxiv.org/pdf/1612.06212v1
2016-12-19T14:59:14Z
2016-12-19T14:59:14Z
A recurrent neural network without chaos
We introduce an exceptionally simple gated recurrent neural network (RNN) that achieves performance comparable to well-known gated architectures, such as LSTMs and GRUs, on the word-level language modeling task. We prove that our model has simple, predicable and non-chaotic dynamics. This stands in stark contrast to more standard gated architectures, whose underlying dynamical systems exhibit chaotic behavior.
[ "Thomas Laurent and James von Brecht", "['Thomas Laurent' 'James von Brecht']" ]
cs.LG stat.ML
null
1612.06246
null
null
http://arxiv.org/pdf/1612.06246v3
2017-06-06T03:21:09Z
2016-12-19T16:17:56Z
Corralling a Band of Bandit Algorithms
We study the problem of combining multiple bandit algorithms (that is, online learning algorithms with partial feedback) with the goal of creating a master algorithm that performs almost as well as the best base algorithm if it were to be run on its own. The main challenge is that when run with a master, base algorithms unavoidably receive much less feedback and it is thus critical that the master not starve a base algorithm that might perform uncompetitively initially but would eventually outperform others if given enough feedback. We address this difficulty by devising a version of Online Mirror Descent with a special mirror map together with a sophisticated learning rate scheme. We show that this approach manages to achieve a more delicate balance between exploiting and exploring base algorithms than previous works yielding superior regret bounds. Our results are applicable to many settings, such as multi-armed bandits, contextual bandits, and convex bandits. As examples, we present two main applications. The first is to create an algorithm that enjoys worst-case robustness while at the same time performing much better when the environment is relatively easy. The second is to create an algorithm that works simultaneously under different assumptions of the environment, such as different priors or different loss structures.
[ "['Alekh Agarwal' 'Haipeng Luo' 'Behnam Neyshabur' 'Robert E. Schapire']", "Alekh Agarwal, Haipeng Luo, Behnam Neyshabur and Robert E. Schapire" ]
cs.SD cs.LG
null
1612.06287
null
null
http://arxiv.org/pdf/1612.06287v1
2016-12-14T15:40:44Z
2016-12-14T15:40:44Z
VAST : The Virtual Acoustic Space Traveler Dataset
This paper introduces a new paradigm for sound source lo-calization referred to as virtual acoustic space traveling (VAST) and presents a first dataset designed for this purpose. Existing sound source localization methods are either based on an approximate physical model (physics-driven) or on a specific-purpose calibration set (data-driven). With VAST, the idea is to learn a mapping from audio features to desired audio properties using a massive dataset of simulated room impulse responses. This virtual dataset is designed to be maximally representative of the potential audio scenes that the considered system may be evolving in, while remaining reasonably compact. We show that virtually-learned mappings on this dataset generalize to real data, overcoming some intrinsic limitations of traditional binaural sound localization methods based on time differences of arrival.
[ "Cl\\'ement Gaultier (PANAMA), Saurabh Kataria (PANAMA, IIT Kanpur),\n Antoine Deleforge (PANAMA)", "['Clément Gaultier' 'Saurabh Kataria' 'Antoine Deleforge']" ]
cs.LG cs.CR stat.ML
null
1612.06299
null
null
http://arxiv.org/pdf/1612.06299v1
2016-12-19T18:12:20Z
2016-12-19T18:12:20Z
Simple Black-Box Adversarial Perturbations for Deep Networks
Deep neural networks are powerful and popular learning models that achieve state-of-the-art pattern recognition performance on many computer vision, speech, and language processing tasks. However, these networks have also been shown susceptible to carefully crafted adversarial perturbations which force misclassification of the inputs. Adversarial examples enable adversaries to subvert the expected system behavior leading to undesired consequences and could pose a security risk when these systems are deployed in the real world. In this work, we focus on deep convolutional neural networks and demonstrate that adversaries can easily craft adversarial examples even without any internal knowledge of the target network. Our attacks treat the network as an oracle (black-box) and only assume that the output of the network can be observed on the probed inputs. Our first attack is based on a simple idea of adding perturbation to a randomly selected single pixel or a small set of them. We then improve the effectiveness of this attack by carefully constructing a small set of pixels to perturb by using the idea of greedy local-search. Our proposed attacks also naturally extend to a stronger notion of misclassification. Our extensive experimental results illustrate that even these elementary attacks can reveal a deep neural network's vulnerabilities. The simplicity and effectiveness of our proposed schemes mean that they could serve as a litmus test for designing robust networks.
[ "['Nina Narodytska' 'Shiva Prasad Kasiviswanathan']", "Nina Narodytska, Shiva Prasad Kasiviswanathan" ]
cs.GT cs.AI cs.LG cs.MA stat.ML
null
1612.0634
null
null
null
null
null
Computing Human-Understandable Strategies
Algorithms for equilibrium computation generally make no attempt to ensure that the computed strategies are understandable by humans. For instance the strategies for the strongest poker agents are represented as massive binary files. In many situations, we would like to compute strategies that can actually be implemented by humans, who may have computational limitations and may only be able to remember a small number of features or components of the strategies that have been computed. We study poker games where private information distributions can be arbitrary. We create a large training set of game instances and solutions, by randomly selecting the information probabilities, and present algorithms that learn from the training instances in order to perform well in games with unseen information distributions. We are able to conclude several new fundamental rules about poker strategy that can be easily implemented by humans.
[ "Sam Ganzfried and Farzana Yusuf" ]
null
null
1612.06340
null
null
http://arxiv.org/pdf/1612.06340v2
2017-02-20T17:54:11Z
2016-12-19T20:40:19Z
Computing Human-Understandable Strategies
Algorithms for equilibrium computation generally make no attempt to ensure that the computed strategies are understandable by humans. For instance the strategies for the strongest poker agents are represented as massive binary files. In many situations, we would like to compute strategies that can actually be implemented by humans, who may have computational limitations and may only be able to remember a small number of features or components of the strategies that have been computed. We study poker games where private information distributions can be arbitrary. We create a large training set of game instances and solutions, by randomly selecting the information probabilities, and present algorithms that learn from the training instances in order to perform well in games with unseen information distributions. We are able to conclude several new fundamental rules about poker strategy that can be easily implemented by humans.
[ "['Sam Ganzfried' 'Farzana Yusuf']" ]
cs.CV cs.AI cs.LG cs.NE stat.ML
null
1612.0637
null
null
null
null
null
Learning Features by Watching Objects Move
This paper presents a novel yet intuitive approach to unsupervised feature learning. Inspired by the human visual system, we explore whether low-level motion-based grouping cues can be used to learn an effective visual representation. Specifically, we use unsupervised motion-based segmentation on videos to obtain segments, which we use as 'pseudo ground truth' to train a convolutional network to segment objects from a single frame. Given the extensive evidence that motion plays a key role in the development of the human visual system, we hope that this straightforward approach to unsupervised learning will be more effective than cleverly designed 'pretext' tasks studied in the literature. Indeed, our extensive experiments show that this is the case. When used for transfer learning on object detection, our representation significantly outperforms previous unsupervised approaches across multiple settings, especially when training data for the target task is scarce.
[ "Deepak Pathak, Ross Girshick, Piotr Doll\\'ar, Trevor Darrell, Bharath\n Hariharan" ]
null
null
1612.06370
null
null
http://arxiv.org/pdf/1612.06370v2
2017-04-12T04:28:47Z
2016-12-19T20:56:04Z
Learning Features by Watching Objects Move
This paper presents a novel yet intuitive approach to unsupervised feature learning. Inspired by the human visual system, we explore whether low-level motion-based grouping cues can be used to learn an effective visual representation. Specifically, we use unsupervised motion-based segmentation on videos to obtain segments, which we use as 'pseudo ground truth' to train a convolutional network to segment objects from a single frame. Given the extensive evidence that motion plays a key role in the development of the human visual system, we hope that this straightforward approach to unsupervised learning will be more effective than cleverly designed 'pretext' tasks studied in the literature. Indeed, our extensive experiments show that this is the case. When used for transfer learning on object detection, our representation significantly outperforms previous unsupervised approaches across multiple settings, especially when training data for the target task is scarce.
[ "['Deepak Pathak' 'Ross Girshick' 'Piotr Dollár' 'Trevor Darrell'\n 'Bharath Hariharan']" ]
stat.ML cs.LG
null
1612.0647
null
null
null
null
null
Randomized Clustered Nystrom for Large-Scale Kernel Machines
The Nystrom method has been popular for generating the low-rank approximation of kernel matrices that arise in many machine learning problems. The approximation quality of the Nystrom method depends crucially on the number of selected landmark points and the selection procedure. In this paper, we present a novel algorithm to compute the optimal Nystrom low-approximation when the number of landmark points exceed the target rank. Moreover, we introduce a randomized algorithm for generating landmark points that is scalable to large-scale data sets. The proposed method performs K-means clustering on low-dimensional random projections of a data set and, thus, leads to significant savings for high-dimensional data sets. Our theoretical results characterize the tradeoffs between the accuracy and efficiency of our proposed method. Extensive experiments demonstrate the competitive performance as well as the efficiency of our proposed method.
[ "Farhad Pourkamali-Anaraki, Stephen Becker" ]
null
null
1612.06470
null
null
http://arxiv.org/pdf/1612.06470v1
2016-12-20T01:07:04Z
2016-12-20T01:07:04Z
Randomized Clustered Nystrom for Large-Scale Kernel Machines
The Nystrom method has been popular for generating the low-rank approximation of kernel matrices that arise in many machine learning problems. The approximation quality of the Nystrom method depends crucially on the number of selected landmark points and the selection procedure. In this paper, we present a novel algorithm to compute the optimal Nystrom low-approximation when the number of landmark points exceed the target rank. Moreover, we introduce a randomized algorithm for generating landmark points that is scalable to large-scale data sets. The proposed method performs K-means clustering on low-dimensional random projections of a data set and, thus, leads to significant savings for high-dimensional data sets. Our theoretical results characterize the tradeoffs between the accuracy and efficiency of our proposed method. Extensive experiments demonstrate the competitive performance as well as the efficiency of our proposed method.
[ "['Farhad Pourkamali-Anaraki' 'Stephen Becker']" ]
cs.LG cs.AI
null
1612.06505
null
null
http://arxiv.org/pdf/1612.06505v4
2017-11-06T01:03:44Z
2016-12-20T04:54:49Z
Parallelized Tensor Train Learning of Polynomial Classifiers
In pattern classification, polynomial classifiers are well-studied methods as they are capable of generating complex decision surfaces. Unfortunately, the use of multivariate polynomials is limited to kernels as in support vector machines, because polynomials quickly become impractical for high-dimensional problems. In this paper, we effectively overcome the curse of dimensionality by employing the tensor train format to represent a polynomial classifier. Based on the structure of tensor trains, two learning algorithms are proposed which involve solving different optimization problems of low computational complexity. Furthermore, we show how both regularization to prevent overfitting and parallelization, which enables the use of large training sets, are incorporated into these methods. Both the efficiency and efficacy of our tensor-based polynomial classifier are then demonstrated on the two popular datasets USPS and MNIST.
[ "Zhongming Chen, Kim Batselier, Johan A.K. Suykens, Ngai Wong", "['Zhongming Chen' 'Kim Batselier' 'Johan A. K. Suykens' 'Ngai Wong']" ]
cs.CV cs.LG cs.NE
null
1612.06519
null
null
http://arxiv.org/pdf/1612.06519v1
2016-12-20T06:20:43Z
2016-12-20T06:20:43Z
Exploring the Design Space of Deep Convolutional Neural Networks at Large Scale
In recent years, the research community has discovered that deep neural networks (DNNs) and convolutional neural networks (CNNs) can yield higher accuracy than all previous solutions to a broad array of machine learning problems. To our knowledge, there is no single CNN/DNN architecture that solves all problems optimally. Instead, the "right" CNN/DNN architecture varies depending on the application at hand. CNN/DNNs comprise an enormous design space. Quantitatively, we find that a small region of the CNN design space contains 30 billion different CNN architectures. In this dissertation, we develop a methodology that enables systematic exploration of the design space of CNNs. Our methodology is comprised of the following four themes. 1. Judiciously choosing benchmarks and metrics. 2. Rapidly training CNN models. 3. Defining and describing the CNN design space. 4. Exploring the design space of CNN architectures. Taken together, these four themes comprise an effective methodology for discovering the "right" CNN architectures to meet the needs of practical applications.
[ "['Forrest Iandola']", "Forrest Iandola" ]
stat.ML cs.LG
null
1612.06598
null
null
http://arxiv.org/pdf/1612.06598v1
2016-12-20T10:39:45Z
2016-12-20T10:39:45Z
WoCE: a framework for clustering ensemble by exploiting the wisdom of Crowds theory
The Wisdom of Crowds (WOC), as a theory in the social science, gets a new paradigm in computer science. The WOC theory explains that the aggregate decision made by a group is often better than those of its individual members if specific conditions are satisfied. This paper presents a novel framework for unsupervised and semi-supervised cluster ensemble by exploiting the WOC theory. We employ four conditions in the WOC theory, i.e., diversity, independency, decentralization and aggregation, to guide both the constructing of individual clustering results and the final combination for clustering ensemble. Firstly, independency criterion, as a novel mapping system on the raw data set, removes the correlation between features on our proposed method. Then, decentralization as a novel mechanism generates high-quality individual clustering results. Next, uniformity as a new diversity metric evaluates the generated clustering results. Further, weighted evidence accumulation clustering method is proposed for the final aggregation without using thresholding procedure. Experimental study on varied data sets demonstrates that the proposed approach achieves superior performance to state-of-the-art methods.
[ "Muhammad Yousefnezhad, Sheng-Jun Huang, Daoqiang Zhang", "['Muhammad Yousefnezhad' 'Sheng-Jun Huang' 'Daoqiang Zhang']" ]
cs.LG
null
1612.06623
null
null
http://arxiv.org/pdf/1612.06623v1
2016-12-20T12:15:17Z
2016-12-20T12:15:17Z
Supervised Learning for Optimal Power Flow as a Real-Time Proxy
In this work we design and compare different supervised learning algorithms to compute the cost of Alternating Current Optimal Power Flow (ACOPF). The motivation for quick calculation of OPF cost outcomes stems from the growing need of algorithmic-based long-term and medium-term planning methodologies in power networks. Integrated in a multiple time-horizon coordination framework, we refer to this approximation module as a proxy for predicting short-term decision outcomes without the need of actual simulation and optimization of them. Our method enables fast approximate calculation of OPF cost with less than 1% error on average, achieved in run-times that are several orders of magnitude lower than of exact computation. Several test-cases such as IEEE-RTS96 are used to demonstrate the efficiency of our approach.
[ "['Raphael Canyasse' 'Gal Dalal' 'Shie Mannor']", "Raphael Canyasse, Gal Dalal, Shie Mannor" ]
math.OC cs.LG stat.ML
null
1612.06669
null
null
http://arxiv.org/pdf/1612.06669v1
2016-12-20T14:12:58Z
2016-12-20T14:12:58Z
Enhancing Observability in Distribution Grids using Smart Meter Data
Due to limited metering infrastructure, distribution grids are currently challenged by observability issues. On the other hand, smart meter data, including local voltage magnitudes and power injections, are communicated to the utility operator from grid buses with renewable generation and demand-response programs. This work employs grid data from metered buses towards inferring the underlying grid state. To this end, a coupled formulation of the power flow problem (CPF) is put forth. Exploiting the high variability of injections at metered buses, the controllability of solar inverters, and the relative time-invariance of conventional loads, the idea is to solve the non-linear power flow equations jointly over consecutive time instants. An intuitive and easily verifiable rule pertaining to the locations of metered and non-metered buses on the physical grid is shown to be a necessary and sufficient criterion for local observability in radial networks. To account for noisy smart meter readings, a coupled power system state estimation (CPSSE) problem is further developed. Both CPF and CPSSE tasks are tackled via augmented semi-definite program relaxations. The observability criterion along with the CPF and CPSSE solvers are numerically corroborated using synthetic and actual solar generation and load data on the IEEE 34-bus benchmark feeder.
[ "Siddharth Bhela, Vassilis Kekatos, Sriharsha Veeramachaneni", "['Siddharth Bhela' 'Vassilis Kekatos' 'Sriharsha Veeramachaneni']" ]
cs.LG stat.ML
null
1612.06676
null
null
http://arxiv.org/pdf/1612.06676v2
2016-12-26T11:26:03Z
2016-12-20T14:24:49Z
Multivariate Industrial Time Series with Cyber-Attack Simulation: Fault Detection Using an LSTM-based Predictive Data Model
We adopted an approach based on an LSTM neural network to monitor and detect faults in industrial multivariate time series data. To validate the approach we created a Modelica model of part of a real gasoil plant. By introducing hacks into the logic of the Modelica model, we were able to generate both the roots and causes of fault behavior in the plant. Having a self-consistent data set with labeled faults, we used an LSTM architecture with a forecasting error threshold to obtain precision and recall quality metrics. The dependency of the quality metric on the threshold level is considered. An appropriate mechanism such as "one handle" was introduced for filtering faults that are outside of the plant operator field of interest.
[ "['Pavel Filonov' 'Andrey Lavrentyev' 'Artem Vorontsov']", "Pavel Filonov, Andrey Lavrentyev, Artem Vorontsov" ]
cs.CV cs.AI cs.LG
null
1612.06704
null
null
http://arxiv.org/pdf/1612.06704v1
2016-12-20T15:24:46Z
2016-12-20T15:24:46Z
Action-Driven Object Detection with Top-Down Visual Attentions
A dominant paradigm for deep learning based object detection relies on a "bottom-up" approach using "passive" scoring of class agnostic proposals. These approaches are efficient but lack of holistic analysis of scene-level context. In this paper, we present an "action-driven" detection mechanism using our "top-down" visual attention model. We localize an object by taking sequential actions that the attention model provides. The attention model conditioned with an image region provides required actions to get closer toward a target object. An action at each time step is weak itself but an ensemble of the sequential actions makes a bounding-box accurately converge to a target object boundary. This attention model we call AttentionNet is composed of a convolutional neural network. During our whole detection procedure, we only utilize the actions from a single AttentionNet without any modules for object proposals nor post bounding-box regression. We evaluate our top-down detection mechanism over the PASCAL VOC series and ILSVRC CLS-LOC dataset, and achieve state-of-the-art performances compared to the major bottom-up detection methods. In particular, our detection mechanism shows a strong advantage in elaborate localization by outperforming Faster R-CNN with a margin of +7.1% over PASCAL VOC 2007 when we increase the IoU threshold for positive detection to 0.7.
[ "['Donggeun Yoo' 'Sunggyun Park' 'Kyunghyun Paeng' 'Joon-Young Lee'\n 'In So Kweon']", "Donggeun Yoo, Sunggyun Park, Kyunghyun Paeng, Joon-Young Lee, In So\n Kweon" ]
cs.CV cs.LG
null
1612.06851
null
null
http://arxiv.org/pdf/1612.06851v2
2017-09-19T22:37:40Z
2016-12-20T20:57:59Z
Beyond Skip Connections: Top-Down Modulation for Object Detection
In recent years, we have seen tremendous progress in the field of object detection. Most of the recent improvements have been achieved by targeting deeper feedforward networks. However, many hard object categories such as bottle, remote, etc. require representation of fine details and not just coarse, semantic representations. But most of these fine details are lost in the early convolutional layers. What we need is a way to incorporate finer details from lower layers into the detection architecture. Skip connections have been proposed to combine high-level and low-level features, but we argue that selecting the right features from low-level requires top-down contextual information. Inspired by the human visual pathway, in this paper we propose top-down modulations as a way to incorporate fine details into the detection framework. Our approach supplements the standard bottom-up, feedforward ConvNet with a top-down modulation (TDM) network, connected using lateral connections. These connections are responsible for the modulation of lower layer filters, and the top-down network handles the selection and integration of contextual information and low-level features. The proposed TDM architecture provides a significant boost on the COCO testdev benchmark, achieving 28.6 AP for VGG16, 35.2 AP for ResNet101, and 37.3 for InceptionResNetv2 network, without any bells and whistles (e.g., multi-scale, iterative box refinement, etc.).
[ "['Abhinav Shrivastava' 'Rahul Sukthankar' 'Jitendra Malik' 'Abhinav Gupta']", "Abhinav Shrivastava, Rahul Sukthankar, Jitendra Malik, Abhinav Gupta" ]
cs.LG
null
1612.06856
null
null
http://arxiv.org/pdf/1612.06856v2
2016-12-22T20:58:04Z
2016-12-20T19:33:35Z
Temporal Feature Selection on Networked Time Series
This paper formulates the problem of learning discriminative features (\textit{i.e.,} segments) from networked time series data considering the linked information among time series. For example, social network users are considered to be social sensors that continuously generate social signals (tweets) represented as a time series. The discriminative segments are often referred to as \emph{shapelets} in a time series. Extracting shapelets for time series classification has been widely studied. However, existing works on shapelet selection assume that the time series are independent and identically distributed (i.i.d.). This assumption restricts their applications to social networked time series analysis, since a user's actions can be correlated to his/her social affiliations. In this paper we propose a new Network Regularized Least Squares (NetRLS) feature selection model that combines typical time series data and user network data for analysis. Experiments on real-world networked time series Twitter and DBLP data demonstrate the performance of the proposed method. NetRLS performs better than LTS, the state-of-the-art time series feature selection approach, on real-world data.
[ "Haishuai Wang, Jia Wu, Peng Zhang, Chengqi Zhang", "['Haishuai Wang' 'Jia Wu' 'Peng Zhang' 'Chengqi Zhang']" ]
stat.ME cs.LG stat.ML
null
1612.06879
null
null
http://arxiv.org/pdf/1612.06879v1
2016-12-09T19:25:27Z
2016-12-09T19:25:27Z
Robust mixture of experts modeling using the skew $t$ distribution
Mixture of Experts (MoE) is a popular framework in the fields of statistics and machine learning for modeling heterogeneity in data for regression, classification and clustering. MoE for continuous data are usually based on the normal distribution. However, it is known that for data with asymmetric behavior, heavy tails and atypical observations, the use of the normal distribution is unsuitable. We introduce a new robust non-normal mixture of experts modeling using the skew $t$ distribution. The proposed skew $t$ mixture of experts, named STMoE, handles these issues of the normal mixtures experts regarding possibly skewed, heavy-tailed and noisy data. We develop a dedicated expectation conditional maximization (ECM) algorithm to estimate the model parameters by monotonically maximizing the observed data log-likelihood. We describe how the presented model can be used in prediction and in model-based clustering of regression data. Numerical experiments carried out on simulated data show the effectiveness and the robustness of the proposed model in fitting non-linear regression functions as well as in model-based clustering. Then, the proposed model is applied to the real-world data of tone perception for musical data analysis, and the one of temperature anomalies for the analysis of climate change data. The obtained results confirm the usefulness of the model for practical data analysis applications.
[ "['Faicel Chamroukhi']", "Faicel Chamroukhi" ]
cs.CV cs.CL cs.LG
null
1612.0689
null
null
null
null
null
CLEVR: A Diagnostic Dataset for Compositional Language and Elementary Visual Reasoning
When building artificial intelligence systems that can reason and answer questions about visual data, we need diagnostic tests to analyze our progress and discover shortcomings. Existing benchmarks for visual question answering can help, but have strong biases that models can exploit to correctly answer questions without reasoning. They also conflate multiple sources of error, making it hard to pinpoint model weaknesses. We present a diagnostic dataset that tests a range of visual reasoning abilities. It contains minimal biases and has detailed annotations describing the kind of reasoning each question requires. We use this dataset to analyze a variety of modern visual reasoning systems, providing novel insights into their abilities and limitations.
[ "Justin Johnson and Bharath Hariharan and Laurens van der Maaten and Li\n Fei-Fei and C. Lawrence Zitnick and Ross Girshick" ]
null
null
1612.06890
null
null
http://arxiv.org/pdf/1612.06890v1
2016-12-20T21:40:40Z
2016-12-20T21:40:40Z
CLEVR: A Diagnostic Dataset for Compositional Language and Elementary Visual Reasoning
When building artificial intelligence systems that can reason and answer questions about visual data, we need diagnostic tests to analyze our progress and discover shortcomings. Existing benchmarks for visual question answering can help, but have strong biases that models can exploit to correctly answer questions without reasoning. They also conflate multiple sources of error, making it hard to pinpoint model weaknesses. We present a diagnostic dataset that tests a range of visual reasoning abilities. It contains minimal biases and has detailed annotations describing the kind of reasoning each question requires. We use this dataset to analyze a variety of modern visual reasoning systems, providing novel insights into their abilities and limitations.
[ "['Justin Johnson' 'Bharath Hariharan' 'Laurens van der Maaten'\n 'Li Fei-Fei' 'C. Lawrence Zitnick' 'Ross Girshick']" ]
cs.IR cs.LG
null
1612.06935
null
null
http://arxiv.org/pdf/1612.06935v6
2018-12-05T03:56:00Z
2016-12-21T01:01:49Z
Personalized Video Recommendation Using Rich Contents from Videos
Video recommendation has become an essential way of helping people explore the massive videos and discover the ones that may be of interest to them. In the existing video recommender systems, the models make the recommendations based on the user-video interactions and single specific content features. When the specific content features are unavailable, the performance of the existing models will seriously deteriorate. Inspired by the fact that rich contents (e.g., text, audio, motion, and so on) exist in videos, in this paper, we explore how to use these rich contents to overcome the limitations caused by the unavailability of the specific ones. Specifically, we propose a novel general framework that incorporates arbitrary single content feature with user-video interactions, named as collaborative embedding regression (CER) model, to make effective video recommendation in both in-matrix and out-of-matrix scenarios. Our extensive experiments on two real-world large-scale datasets show that CER beats the existing recommender models with any single content feature and is more time efficient. In addition, we propose a priority-based late fusion (PRI) method to gain the benefit brought by the integrating the multiple content features. The corresponding experiment shows that PRI brings real performance improvement to the baseline and outperforms the existing fusion methods.
[ "Xingzhong Du, Hongzhi Yin, Ling Chen, Yang Wang, Yi Yang, Xiaofang\n Zhou", "['Xingzhong Du' 'Hongzhi Yin' 'Ling Chen' 'Yang Wang' 'Yi Yang'\n 'Xiaofang Zhou']" ]
stat.ML cs.LG
null
1612.07019
null
null
http://arxiv.org/pdf/1612.07019v1
2016-12-21T09:10:48Z
2016-12-21T09:10:48Z
Robust Learning with Kernel Mean p-Power Error Loss
Correntropy is a second order statistical measure in kernel space, which has been successfully applied in robust learning and signal processing. In this paper, we define a nonsecond order statistical measure in kernel space, called the kernel mean-p power error (KMPE), including the correntropic loss (CLoss) as a special case. Some basic properties of KMPE are presented. In particular, we apply the KMPE to extreme learning machine (ELM) and principal component analysis (PCA), and develop two robust learning algorithms, namely ELM-KMPE and PCA-KMPE. Experimental results on synthetic and benchmark data show that the developed algorithms can achieve consistently better performance when compared with some existing methods.
[ "['Badong Chen' 'Lei Xing' 'Xin Wang' 'Jing Qin' 'Nanning Zheng']", "Badong Chen, Lei Xing, Xin Wang, Jing Qin, Nanning Zheng" ]
cs.CV cs.LG
null
1612.07086
null
null
http://arxiv.org/pdf/1612.07086v3
2017-08-02T12:33:50Z
2016-12-21T13:04:18Z
An Empirical Study of Language CNN for Image Captioning
Language Models based on recurrent neural networks have dominated recent image caption generation tasks. In this paper, we introduce a Language CNN model which is suitable for statistical language modeling tasks and shows competitive performance in image captioning. In contrast to previous models which predict next word based on one previous word and hidden state, our language CNN is fed with all the previous words and can model the long-range dependencies of history words, which are critical for image captioning. The effectiveness of our approach is validated on two datasets MS COCO and Flickr30K. Our extensive experimental results show that our method outperforms the vanilla recurrent neural network based language models and is competitive with the state-of-the-art methods.
[ "['Jiuxiang Gu' 'Gang Wang' 'Jianfei Cai' 'Tsuhan Chen']", "Jiuxiang Gu, Gang Wang, Jianfei Cai, Tsuhan Chen" ]
cs.IR cs.LG
null
1612.07117
null
null
http://arxiv.org/pdf/1612.07117v1
2016-12-20T15:02:41Z
2016-12-20T15:02:41Z
Classification and Learning-to-rank Approaches for Cross-Device Matching at CIKM Cup 2016
In this paper, we propose two methods for tackling the problem of cross-device matching for online advertising at CIKM Cup 2016. The first method considers the matching problem as a binary classification task and solve it by utilizing ensemble learning techniques. The second method defines the matching problem as a ranking task and effectively solve it with using learning-to-rank algorithms. The results show that the proposed methods obtain promising results, in which the ranking-based method outperforms the classification-based method for the task.
[ "Nam Khanh Tran", "['Nam Khanh Tran']" ]
cs.CV cs.AR cs.LG
10.1145/3020078.3021744
1612.07119
null
null
http://arxiv.org/abs/1612.07119v1
2016-12-01T22:19:47Z
2016-12-01T22:19:47Z
FINN: A Framework for Fast, Scalable Binarized Neural Network Inference
Research has shown that convolutional neural networks contain significant redundancy, and high classification accuracy can be obtained even when weights and activations are reduced from floating point to binary values. In this paper, we present FINN, a framework for building fast and flexible FPGA accelerators using a flexible heterogeneous streaming architecture. By utilizing a novel set of optimizations that enable efficient mapping of binarized neural networks to hardware, we implement fully connected, convolutional and pooling layers, with per-layer compute resources being tailored to user-provided throughput requirements. On a ZC706 embedded FPGA platform drawing less than 25 W total system power, we demonstrate up to 12.3 million image classifications per second with 0.31 {\mu}s latency on the MNIST dataset with 95.8% accuracy, and 21906 image classifications per second with 283 {\mu}s latency on the CIFAR-10 and SVHN datasets with respectively 80.1% and 94.9% accuracy. To the best of our knowledge, ours are the fastest classification rates reported to date on these benchmarks.
[ "['Yaman Umuroglu' 'Nicholas J. Fraser' 'Giulio Gambardella'\n 'Michaela Blott' 'Philip Leong' 'Magnus Jahre' 'Kees Vissers']", "Yaman Umuroglu, Nicholas J. Fraser, Giulio Gambardella, Michaela\n Blott, Philip Leong, Magnus Jahre, Kees Vissers" ]
cs.RO cs.AI cs.LG cs.SY
null
1612.07139
null
null
http://arxiv.org/pdf/1612.07139v4
2018-04-09T03:46:53Z
2016-12-21T14:31:47Z
A Survey of Deep Network Solutions for Learning Control in Robotics: From Reinforcement to Imitation
Deep learning techniques have been widely applied, achieving state-of-the-art results in various fields of study. This survey focuses on deep learning solutions that target learning control policies for robotics applications. We carry out our discussions on the two main paradigms for learning control with deep networks: deep reinforcement learning and imitation learning. For deep reinforcement learning (DRL), we begin from traditional reinforcement learning algorithms, showing how they are extended to the deep context and effective mechanisms that could be added on top of the DRL algorithms. We then introduce representative works that utilize DRL to solve navigation and manipulation tasks in robotics. We continue our discussion on methods addressing the challenge of the reality gap for transferring DRL policies trained in simulation to real-world scenarios, and summarize robotics simulation platforms for conducting DRL research. For imitation leaning, we go through its three main categories, behavior cloning, inverse reinforcement learning and generative adversarial imitation learning, by introducing their formulations and their corresponding robotics applications. Finally, we discuss the open challenges and research frontiers.
[ "['Lei Tai' 'Jingwei Zhang' 'Ming Liu' 'Joschka Boedecker'\n 'Wolfram Burgard']", "Lei Tai and Jingwei Zhang and Ming Liu and Joschka Boedecker and\n Wolfram Burgard" ]
cs.LG
null
1612.07141
null
null
http://arxiv.org/pdf/1612.07141v3
2019-01-28T13:20:31Z
2016-12-21T14:33:32Z
Robust Classification of Graph-Based Data
A graph-based classification method is proposed for semi-supervised learning in the case of Euclidean data and for classification in the case of graph data. Our manifold learning technique is based on a convex optimization problem involving a convex quadratic regularization term and a concave quadratic loss function with a trade-off parameter carefully chosen so that the objective function remains convex. As shown empirically, the advantage of considering a concave loss function is that the learning problem becomes more robust in the presence of noisy labels. Furthermore, the loss function considered here is then more similar to a classification loss while several other methods treat graph-based classification problems as regression problems.
[ "['Carlos M. Alaíz' 'Michaël Fanuel' 'Johan A. K. Suykens']", "Carlos M. Ala\\'iz, Micha\\\"el Fanuel, Johan A. K. Suykens" ]
cs.LG
null
1612.07146
null
null
http://arxiv.org/pdf/1612.07146v3
2018-07-05T08:28:41Z
2016-12-21T14:35:26Z
Collaborative Filtering with User-Item Co-Autoregressive Models
Deep neural networks have shown promise in collaborative filtering (CF). However, existing neural approaches are either user-based or item-based, which cannot leverage all the underlying information explicitly. We propose CF-UIcA, a neural co-autoregressive model for CF tasks, which exploits the structural correlation in the domains of both users and items. The co-autoregression allows extra desired properties to be incorporated for different tasks. Furthermore, we develop an efficient stochastic learning algorithm to handle large scale datasets. We evaluate CF-UIcA on two popular benchmarks: MovieLens 1M and Netflix, and achieve state-of-the-art performance in both rating prediction and top-N recommendation tasks, which demonstrates the effectiveness of CF-UIcA.
[ "Chao Du, Chongxuan Li, Yin Zheng, Jun Zhu, Bo Zhang", "['Chao Du' 'Chongxuan Li' 'Yin Zheng' 'Jun Zhu' 'Bo Zhang']" ]
cs.CL cs.CV cs.GT cs.LG cs.MA
null
1612.07182
null
null
http://arxiv.org/pdf/1612.07182v2
2017-03-05T21:40:51Z
2016-12-21T15:27:06Z
Multi-Agent Cooperation and the Emergence of (Natural) Language
The current mainstream approach to train natural language systems is to expose them to large amounts of text. This passive learning is problematic if we are interested in developing interactive machines, such as conversational agents. We propose a framework for language learning that relies on multi-agent communication. We study this learning in the context of referential games. In these games, a sender and a receiver see a pair of images. The sender is told one of them is the target and is allowed to send a message from a fixed, arbitrary vocabulary to the receiver. The receiver must rely on this message to identify the target. Thus, the agents develop their own language interactively out of the need to communicate. We show that two networks with simple configurations are able to learn to coordinate in the referential game. We further explore how to make changes to the game environment to cause the "word meanings" induced in the game to better reflect intuitive semantic properties of the images. In addition, we present a simple strategy for grounding the agents' code into natural language. Both of these are necessary steps towards developing machines that are able to communicate with humans productively.
[ "['Angeliki Lazaridou' 'Alexander Peysakhovich' 'Marco Baroni']", "Angeliki Lazaridou, Alexander Peysakhovich, Marco Baroni" ]
stat.ML cs.LG stat.ME
null
1612.07222
null
null
http://arxiv.org/pdf/1612.07222v1
2016-12-21T16:24:27Z
2016-12-21T16:24:27Z
Bayesian Decision Process for Cost-Efficient Dynamic Ranking via Crowdsourcing
Rank aggregation based on pairwise comparisons over a set of items has a wide range of applications. Although considerable research has been devoted to the development of rank aggregation algorithms, one basic question is how to efficiently collect a large amount of high-quality pairwise comparisons for the ranking purpose. Because of the advent of many crowdsourcing services, a crowd of workers are often hired to conduct pairwise comparisons with a small monetary reward for each pair they compare. Since different workers have different levels of reliability and different pairs have different levels of ambiguity, it is desirable to wisely allocate the limited budget for comparisons among the pairs of items and workers so that the global ranking can be accurately inferred from the comparison results. To this end, we model the active sampling problem in crowdsourced ranking as a Bayesian Markov decision process, which dynamically selects item pairs and workers to improve the ranking accuracy under a budget constraint. We further develop a computationally efficient sampling policy based on knowledge gradient as well as a moment matching technique for posterior approximation. Experimental evaluations on both synthetic and real data show that the proposed policy achieves high ranking accuracy with a lower labeling cost.
[ "['Xi Chen' 'Kevin Jiao' 'Qihang Lin']", "Xi Chen, Kevin Jiao, Qihang Lin" ]
cs.LG
null
1612.07307
null
null
http://arxiv.org/pdf/1612.07307v2
2017-03-09T18:29:09Z
2016-12-21T20:29:26Z
Loss is its own Reward: Self-Supervision for Reinforcement Learning
Reinforcement learning optimizes policies for expected cumulative reward. Need the supervision be so narrow? Reward is delayed and sparse for many tasks, making it a difficult and impoverished signal for end-to-end optimization. To augment reward, we consider a range of self-supervised tasks that incorporate states, actions, and successors to provide auxiliary losses. These losses offer ubiquitous and instantaneous supervision for representation learning even in the absence of reward. While current results show that learning from reward alone is feasible, pure reinforcement learning methods are constrained by computational and data efficiency issues that can be remedied by auxiliary losses. Self-supervised pre-training and joint optimization improve the data efficiency and policy returns of end-to-end reinforcement learning.
[ "Evan Shelhamer, Parsa Mahmoudieh, Max Argus, Trevor Darrell", "['Evan Shelhamer' 'Parsa Mahmoudieh' 'Max Argus' 'Trevor Darrell']" ]
math.OC cs.LG
null
1612.07335
null
null
http://arxiv.org/pdf/1612.07335v1
2016-12-21T21:12:27Z
2016-12-21T21:12:27Z
Distributed Dictionary Learning
The paper studies distributed Dictionary Learning (DL) problems where the learning task is distributed over a multi-agent network with time-varying (nonsymmetric) connectivity. This formulation is relevant, for instance, in big-data scenarios where massive amounts of data are collected/stored in different spatial locations and it is unfeasible to aggregate and/or process all the data in a fusion center, due to resource limitations, communication overhead or privacy considerations. We develop a general distributed algorithmic framework for the (nonconvex) DL problem and establish its asymptotic convergence. The new method hinges on Successive Convex Approximation (SCA) techniques coupled with i) a gradient tracking mechanism instrumental to locally estimate the missing global information; and ii) a consensus step, as a mechanism to distribute the computations among the agents. To the best of our knowledge, this is the first distributed algorithm with provable convergence for the DL problem and, more in general, bi-convex optimization problems over (time-varying) directed graphs.
[ "['Amir Daneshmand' 'Gesualdo Scutari' 'Francisco Facchinei']", "Amir Daneshmand, Gesualdo Scutari, Francisco Facchinei" ]
cs.LG stat.ML
null
1612.07374
null
null
http://arxiv.org/pdf/1612.07374v1
2016-12-21T22:43:08Z
2016-12-21T22:43:08Z
Detecting Unusual Input-Output Associations in Multivariate Conditional Data
Despite tremendous progress in outlier detection research in recent years, the majority of existing methods are designed only to detect unconditional outliers that correspond to unusual data patterns expressed in the joint space of all data attributes. Such methods are not applicable when we seek to detect conditional outliers that reflect unusual responses associated with a given context or condition. This work focuses on multivariate conditional outlier detection, a special type of the conditional outlier detection problem, where data instances consist of multi-dimensional input (context) and output (responses) pairs. We present a novel outlier detection framework that identifies abnormal input-output associations in data with the help of a decomposable conditional probabilistic model that is learned from all data instances. Since components of this model can vary in their quality, we combine them with the help of weights reflecting their reliability in assessment of outliers. We study two ways of calculating the component weights: global that relies on all data, and local that relies only on instances similar to the target instance. Experimental results on data from various domains demonstrate the ability of our framework to successfully identify multivariate conditional outliers.
[ "Charmgil Hong, Milos Hauskrecht", "['Charmgil Hong' 'Milos Hauskrecht']" ]
cond-mat.mtrl-sci cs.LG stat.ML
null
1612.07401
null
null
http://arxiv.org/pdf/1612.07401v3
2017-04-28T00:11:29Z
2016-12-22T00:29:25Z
Microstructure Representation and Reconstruction of Heterogeneous Materials via Deep Belief Network for Computational Material Design
Integrated Computational Materials Engineering (ICME) aims to accelerate optimal design of complex material systems by integrating material science and design automation. For tractable ICME, it is required that (1) a structural feature space be identified to allow reconstruction of new designs, and (2) the reconstruction process be property-preserving. The majority of existing structural presentation schemes rely on the designer's understanding of specific material systems to identify geometric and statistical features, which could be biased and insufficient for reconstructing physically meaningful microstructures of complex material systems. In this paper, we develop a feature learning mechanism based on convolutional deep belief network to automate a two-way conversion between microstructures and their lower-dimensional feature representations, and to achieves a 1000-fold dimension reduction from the microstructure space. The proposed model is applied to a wide spectrum of heterogeneous material systems with distinct microstructural features including Ti-6Al-4V alloy, Pb63-Sn37 alloy, Fontainebleau sandstone, and Spherical colloids, to produce material reconstructions that are close to the original samples with respect to 2-point correlation functions and mean critical fracture strength. This capability is not achieved by existing synthesis methods that rely on the Markovian assumption of material microstructures.
[ "['Ruijin Cang' 'Yaopengxiao Xu' 'Shaohua Chen' 'Yongming Liu' 'Yang Jiao'\n 'Max Yi Ren']", "Ruijin Cang, Yaopengxiao Xu, Shaohua Chen, Yongming Liu, Yang Jiao,\n Max Yi Ren" ]
cs.CL cs.LG
10.1145/3097983.3098115
1612.07411
null
null
http://arxiv.org/abs/1612.07411v2
2017-09-03T21:41:07Z
2016-12-22T01:25:20Z
A Context-aware Attention Network for Interactive Question Answering
Neural network based sequence-to-sequence models in an encoder-decoder framework have been successfully applied to solve Question Answering (QA) problems, predicting answers from statements and questions. However, almost all previous models have failed to consider detailed context information and unknown states under which systems do not have enough information to answer given questions. These scenarios with incomplete or ambiguous information are very common in the setting of Interactive Question Answering (IQA). To address this challenge, we develop a novel model, employing context-dependent word-level attention for more accurate statement representations and question-guided sentence-level attention for better context modeling. We also generate unique IQA datasets to test our model, which will be made publicly available. Employing these attention mechanisms, our model accurately understands when it can output an answer or when it requires generating a supplementary question for additional input depending on different contexts. When available, user's feedback is encoded and directly applied to update sentence-level attention to infer an answer. Extensive experiments on QA and IQA datasets quantitatively demonstrate the effectiveness of our model with significant improvement over state-of-the-art conventional QA models.
[ "Huayu Li, Martin Renqiang Min, Yong Ge, Asim Kadav", "['Huayu Li' 'Martin Renqiang Min' 'Yong Ge' 'Asim Kadav']" ]
cs.LG stat.ML
null
1612.07454
null
null
http://arxiv.org/pdf/1612.07454v1
2016-12-22T06:17:01Z
2016-12-22T06:17:01Z
How to Train Your Deep Neural Network with Dictionary Learning
Currently there are two predominant ways to train deep neural networks. The first one uses restricted Boltzmann machine (RBM) and the second one autoencoders. RBMs are stacked in layers to form deep belief network (DBN); the final representation layer is attached to the target to complete the deep neural network. Autoencoders are nested one inside the other to form stacked autoencoders; once the stcaked autoencoder is learnt the decoder portion is detached and the target attached to the deepest layer of the encoder to form the deep neural network. This work proposes a new approach to train deep neural networks using dictionary learning as the basic building block; the idea is to use the features from the shallower layer as inputs for training the next deeper layer. One can use any type of dictionary learning (unsupervised, supervised, discriminative etc.) as basic units till the pre-final layer. In the final layer one needs to use the label consistent dictionary learning formulation for classification. We compare our proposed framework with existing state-of-the-art deep learning techniques on benchmark problems; we are always within the top 10 results. In actual problems of age and gender classification, we are better than the best known techniques.
[ "['Vanika Singhal' 'Shikha Singh' 'Angshul Majumdar']", "Vanika Singhal, Shikha Singh and Angshul Majumdar" ]
cs.LG cs.DS
null
1612.07516
null
null
http://arxiv.org/pdf/1612.07516v3
2018-09-27T06:50:30Z
2016-12-22T10:10:11Z
On Coreset Constructions for the Fuzzy $K$-Means Problem
The fuzzy $K$-means problem is a popular generalization of the well-known $K$-means problem to soft clusterings. We present the first coresets for fuzzy $K$-means with size linear in the dimension, polynomial in the number of clusters, and poly-logarithmic in the number of points. We show that these coresets can be employed in the computation of a $(1+\epsilon)$-approximation for fuzzy $K$-means, improving previously presented results. We further show that our coresets can be maintained in an insertion-only streaming setting, where data points arrive one-by-one.
[ "Johannes Bl\\\"omer, Sascha Brauer, Kathrin Bujna", "['Johannes Blömer' 'Sascha Brauer' 'Kathrin Bujna']" ]
cs.SD cs.LG stat.ML
null
1612.07523
null
null
http://arxiv.org/pdf/1612.07523v1
2016-12-22T10:14:59Z
2016-12-22T10:14:59Z
Robustness of Voice Conversion Techniques Under Mismatched Conditions
Most of the existing studies on voice conversion (VC) are conducted in acoustically matched conditions between source and target signal. However, the robustness of VC methods in presence of mismatch remains unknown. In this paper, we report a comparative analysis of different VC techniques under mismatched conditions. The extensive experiments with five different VC techniques on CMU ARCTIC corpus suggest that performance of VC methods substantially degrades in noisy conditions. We have found that bilinear frequency warping with amplitude scaling (BLFWAS) outperforms other methods in most of the noisy conditions. We further explore the suitability of different speech enhancement techniques for robust conversion. The objective evaluation results indicate that spectral subtraction and log minimum mean square error (logMMSE) based speech enhancement techniques can be used to improve the performance in specific noisy conditions.
[ "['Monisankha Pal' 'Dipjyoti Paul' 'Md Sahidullah' 'Goutam Saha']", "Monisankha Pal, Dipjyoti Paul, Md Sahidullah, Goutam Saha" ]
cs.AI cs.LG stat.ML
null
1612.07548
null
null
http://arxiv.org/pdf/1612.07548v1
2016-12-22T11:30:35Z
2016-12-22T11:30:35Z
Non-Deterministic Policy Improvement Stabilizes Approximated Reinforcement Learning
This paper investigates a type of instability that is linked to the greedy policy improvement in approximated reinforcement learning. We show empirically that non-deterministic policy improvement can stabilize methods like LSPI by controlling the improvements' stochasticity. Additionally we show that a suitable representation of the value function also stabilizes the solution to some degree. The presented approach is simple and should also be easily transferable to more sophisticated algorithms like deep reinforcement learning.
[ "Wendelin B\\\"ohmer and Rong Guo and Klaus Obermayer", "['Wendelin Böhmer' 'Rong Guo' 'Klaus Obermayer']" ]
cs.LG
null
1612.07562
null
null
null
null
null
On the function approximation error for risk-sensitive reinforcement learning
In this paper we obtain several informative error bounds on function approximation for the policy evaluation algorithm proposed by Basu et al. when the aim is to find the risk-sensitive cost represented using exponential utility. The main idea is to use classical Bapat's inequality and to use Perron-Frobenius eigenvectors (exists if we assume irreducible Markov chain) to get the new bounds. The novelty of our approach is that we use the irreduciblity of Markov chain to get the new bounds whereas the earlier work by Basu et al. used spectral variation bound which is true for any matrix. We also give examples where all our bounds achieve the "actual error" whereas the earlier bound given by Basu et al. is much weaker in comparison. We show that this happens due to the absence of difference term in the earlier bound which is always present in all our bounds when the state space is large. Additionally, we discuss how all our bounds compare with each other. As a corollary of our main result we provide a bound between largest eigenvalues of two irreducibile matrices in terms of the matrix entries.
[ "Prasenjit Karmakar, Shalabh Bhatnagar" ]
null
null
1612.07562v
null
null
http://arxiv.org/pdf/1612.07562v15
2019-10-22T14:48:35Z
2016-12-22T12:05:29Z
On the function approximation error for risk-sensitive reinforcement learning
In this paper we obtain several informative error bounds on function approximation for the policy evaluation algorithm proposed by Basu et al. when the aim is to find the risk-sensitive cost represented using exponential utility. The main idea is to use classical Bapat's inequality and to use Perron-Frobenius eigenvectors (exists if we assume irreducible Markov chain) to get the new bounds. The novelty of our approach is that we use the irreduciblity of Markov chain to get the new bounds whereas the earlier work by Basu et al. used spectral variation bound which is true for any matrix. We also give examples where all our bounds achieve the "actual error" whereas the earlier bound given by Basu et al. is much weaker in comparison. We show that this happens due to the absence of difference term in the earlier bound which is always present in all our bounds when the state space is large. Additionally, we discuss how all our bounds compare with each other. As a corollary of our main result we provide a bound between largest eigenvalues of two irreducibile matrices in terms of the matrix entries.
[ "['Prasenjit Karmakar' 'Shalabh Bhatnagar']" ]
stat.ML cs.LG
null
1612.07597
null
null
http://arxiv.org/pdf/1612.07597v2
2017-03-16T12:21:36Z
2016-12-22T13:53:42Z
Finding Statistically Significant Attribute Interactions
In many data exploration tasks it is meaningful to identify groups of attribute interactions that are specific to a variable of interest. For instance, in a dataset where the attributes are medical markers and the variable of interest (class variable) is binary indicating presence/absence of disease, we would like to know which medical markers interact with respect to the binary class label. These interactions are useful in several practical applications, for example, to gain insight into the structure of the data, in feature selection, and in data anonymisation. We present a novel method, based on statistical significance testing, that can be used to verify if the data set has been created by a given factorised class-conditional joint distribution, where the distribution is parametrised by a partition of its attributes. Furthermore, we provide a method, named ASTRID, for automatically finding a partition of attributes describing the distribution that has generated the data. State-of-the-art classifiers are utilised to capture the interactions present in the data by systematically breaking attribute interactions and observing the effect of this breaking on classifier performance. We empirically demonstrate the utility of the proposed method with examples using real and synthetic data.
[ "['Andreas Henelius' 'Antti Ukkonen' 'Kai Puolamäki']", "Andreas Henelius, Antti Ukkonen, Kai Puolam\\\"aki" ]
cs.LG stat.ML
null
1612.0764
null
null
null
null
null
Deep Learning and Its Applications to Machine Health Monitoring: A Survey
Since 2006, deep learning (DL) has become a rapidly growing research direction, redefining state-of-the-art performances in a wide range of areas such as object recognition, image segmentation, speech recognition and machine translation. In modern manufacturing systems, data-driven machine health monitoring is gaining in popularity due to the widespread deployment of low-cost sensors and their connection to the Internet. Meanwhile, deep learning provides useful tools for processing and analyzing these big machinery data. The main purpose of this paper is to review and summarize the emerging research work of deep learning on machine health monitoring. After the brief introduction of deep learning techniques, the applications of deep learning in machine health monitoring systems are reviewed mainly from the following aspects: Auto-encoder (AE) and its variants, Restricted Boltzmann Machines and its variants including Deep Belief Network (DBN) and Deep Boltzmann Machines (DBM), Convolutional Neural Networks (CNN) and Recurrent Neural Networks (RNN). Finally, some new trends of DL-based machine health monitoring methods are discussed.
[ "Rui Zhao, Ruqiang Yan, Zhenghua Chen, Kezhi Mao, Peng Wang and Robert\n X. Gao" ]
null
null
1612.07640
null
null
http://arxiv.org/pdf/1612.07640v1
2016-12-16T04:56:30Z
2016-12-16T04:56:30Z
Deep Learning and Its Applications to Machine Health Monitoring: A Survey
Since 2006, deep learning (DL) has become a rapidly growing research direction, redefining state-of-the-art performances in a wide range of areas such as object recognition, image segmentation, speech recognition and machine translation. In modern manufacturing systems, data-driven machine health monitoring is gaining in popularity due to the widespread deployment of low-cost sensors and their connection to the Internet. Meanwhile, deep learning provides useful tools for processing and analyzing these big machinery data. The main purpose of this paper is to review and summarize the emerging research work of deep learning on machine health monitoring. After the brief introduction of deep learning techniques, the applications of deep learning in machine health monitoring systems are reviewed mainly from the following aspects: Auto-encoder (AE) and its variants, Restricted Boltzmann Machines and its variants including Deep Belief Network (DBN) and Deep Boltzmann Machines (DBM), Convolutional Neural Networks (CNN) and Recurrent Neural Networks (RNN). Finally, some new trends of DL-based machine health monitoring methods are discussed.
[ "['Rui Zhao' 'Ruqiang Yan' 'Zhenghua Chen' 'Kezhi Mao' 'Peng Wang'\n 'Robert X. Gao']" ]
stat.ML cs.LG
null
1612.07659
null
null
http://arxiv.org/pdf/1612.07659v1
2016-12-22T15:53:57Z
2016-12-22T15:53:57Z
Structured Sequence Modeling with Graph Convolutional Recurrent Networks
This paper introduces Graph Convolutional Recurrent Network (GCRN), a deep learning model able to predict structured sequences of data. Precisely, GCRN is a generalization of classical recurrent neural networks (RNN) to data structured by an arbitrary graph. Such structured sequences can represent series of frames in videos, spatio-temporal measurements on a network of sensors, or random walks on a vocabulary graph for natural language modeling. The proposed model combines convolutional neural networks (CNN) on graphs to identify spatial structures and RNN to find dynamic patterns. We study two possible architectures of GCRN, and apply the models to two practical problems: predicting moving MNIST data, and modeling natural language with the Penn Treebank dataset. Experiments show that exploiting simultaneously graph spatial and dynamic information about data can improve both precision and learning speed.
[ "Youngjoo Seo, Micha\\\"el Defferrard, Pierre Vandergheynst, Xavier\n Bresson", "['Youngjoo Seo' 'Michaël Defferrard' 'Pierre Vandergheynst'\n 'Xavier Bresson']" ]
hep-ph cs.LG physics.data-an
10.1088/1748-0221/12/05/T05005
1612.07725
null
null
http://arxiv.org/abs/1612.07725v3
2017-05-30T19:03:03Z
2016-12-21T20:01:37Z
Stacking machine learning classifiers to identify Higgs bosons at the LHC
Machine learning (ML) algorithms have been employed in the problem of classifying signal and background events with high accuracy in particle physics. In this paper, we compare the performance of a widespread ML technique, namely, \emph{stacked generalization}, against the results of two state-of-art algorithms: (1) a deep neural network (DNN) in the task of discovering a new neutral Higgs boson and (2) a scalable machine learning system for tree boosting, in the Standard Model Higgs to tau leptons channel, both at the 8 TeV LHC. In a cut-and-count analysis, \emph{stacking} three algorithms performed around 16\% worse than DNN but demanding far less computation efforts, however, the same \emph{stacking} outperforms boosted decision trees. Using the stacked classifiers in a multivariate statistical analysis (MVA), on the other hand, significantly enhances the statistical significance compared to cut-and-count in both Higgs processes, suggesting that combining an ensemble of simpler and faster ML algorithms with MVA tools is a better approach than building a complex state-of-art algorithm for cut-and-count.
[ "Alexandre Alves", "['Alexandre Alves']" ]
cs.NE cs.AI cs.LG
null
1612.07771
null
null
http://arxiv.org/pdf/1612.07771v3
2017-03-14T21:27:03Z
2016-12-22T19:57:35Z
Highway and Residual Networks learn Unrolled Iterative Estimation
The past year saw the introduction of new architectures such as Highway networks and Residual networks which, for the first time, enabled the training of feedforward networks with dozens to hundreds of layers using simple gradient descent. While depth of representation has been posited as a primary reason for their success, there are indications that these architectures defy a popular view of deep learning as a hierarchical computation of increasingly abstract features at each layer. In this report, we argue that this view is incomplete and does not adequately explain several recent findings. We propose an alternative viewpoint based on unrolled iterative estimation -- a group of successive layers iteratively refine their estimates of the same features instead of computing an entirely new representation. We demonstrate that this viewpoint directly leads to the construction of Highway and Residual networks. Finally we provide preliminary experiments to discuss the similarities and differences between the two architectures.
[ "Klaus Greff and Rupesh K. Srivastava and J\\\"urgen Schmidhuber", "['Klaus Greff' 'Rupesh K. Srivastava' 'Jürgen Schmidhuber']" ]
cs.LG cs.LO
null
1612.07823
null
null
http://arxiv.org/pdf/1612.07823v3
2017-05-15T20:07:13Z
2016-12-22T21:58:32Z
Logic-based Clustering and Learning for Time-Series Data
To effectively analyze and design cyberphysical systems (CPS), designers today have to combat the data deluge problem, i.e., the burden of processing intractably large amounts of data produced by complex models and experiments. In this work, we utilize monotonic Parametric Signal Temporal Logic (PSTL) to design features for unsupervised classification of time series data. This enables using off-the-shelf machine learning tools to automatically cluster similar traces with respect to a given PSTL formula. We demonstrate how this technique produces interpretable formulas that are amenable to analysis and understanding using a few representative examples. We illustrate this with case studies related to automotive engine testing, highway traffic analysis, and auto-grading massively open online courses.
[ "Marcell Vazquez-Chanlatte, Jyotirmoy V. Deshmukh, Xiaoqing Jin, Sanjit\n A. Seshia", "['Marcell Vazquez-Chanlatte' 'Jyotirmoy V. Deshmukh' 'Xiaoqing Jin'\n 'Sanjit A. Seshia']" ]
cs.CV cs.LG cs.NE
null
1612.07828
null
null
http://arxiv.org/pdf/1612.07828v2
2017-07-19T21:24:52Z
2016-12-22T22:10:51Z
Learning from Simulated and Unsupervised Images through Adversarial Training
With recent progress in graphics, it has become more tractable to train models on synthetic images, potentially avoiding the need for expensive annotations. However, learning from synthetic images may not achieve the desired performance due to a gap between synthetic and real image distributions. To reduce this gap, we propose Simulated+Unsupervised (S+U) learning, where the task is to learn a model to improve the realism of a simulator's output using unlabeled real data, while preserving the annotation information from the simulator. We develop a method for S+U learning that uses an adversarial network similar to Generative Adversarial Networks (GANs), but with synthetic images as inputs instead of random vectors. We make several key modifications to the standard GAN algorithm to preserve annotations, avoid artifacts, and stabilize training: (i) a 'self-regularization' term, (ii) a local adversarial loss, and (iii) updating the discriminator using a history of refined images. We show that this enables generation of highly realistic images, which we demonstrate both qualitatively and with a user study. We quantitatively evaluate the generated images by training models for gaze estimation and hand pose estimation. We show a significant improvement over using synthetic images, and achieve state-of-the-art results on the MPIIGaze dataset without any labeled real data.
[ "['Ashish Shrivastava' 'Tomas Pfister' 'Oncel Tuzel' 'Josh Susskind'\n 'Wenda Wang' 'Russ Webb']", "Ashish Shrivastava, Tomas Pfister, Oncel Tuzel, Josh Susskind, Wenda\n Wang, Russ Webb" ]
cs.CL cs.IR cs.LG stat.ML
10.1371/journal.pone.0181142
1612.07843
null
null
http://arxiv.org/abs/1612.07843v1
2016-12-23T00:31:30Z
2016-12-23T00:31:30Z
"What is Relevant in a Text Document?": An Interpretable Machine Learning Approach
Text documents can be described by a number of abstract concepts such as semantic category, writing style, or sentiment. Machine learning (ML) models have been trained to automatically map documents to these abstract concepts, allowing to annotate very large text collections, more than could be processed by a human in a lifetime. Besides predicting the text's category very accurately, it is also highly desirable to understand how and why the categorization process takes place. In this paper, we demonstrate that such understanding can be achieved by tracing the classification decision back to individual words using layer-wise relevance propagation (LRP), a recently developed technique for explaining predictions of complex non-linear classifiers. We train two word-based ML models, a convolutional neural network (CNN) and a bag-of-words SVM classifier, on a topic categorization task and adapt the LRP method to decompose the predictions of these models onto words. Resulting scores indicate how much individual words contribute to the overall classification decision. This enables one to distill relevant information from text documents without an explicit semantic information extraction step. We further use the word-wise relevance scores for generating novel vector-based document representations which capture semantic information. Based on these document vectors, we introduce a measure of model explanatory power and show that, although the SVM and CNN models perform similarly in terms of classification accuracy, the latter exhibits a higher level of explainability which makes it more comprehensible for humans and potentially more useful for other applications.
[ "Leila Arras, Franziska Horn, Gr\\'egoire Montavon, Klaus-Robert\n M\\\"uller, Wojciech Samek", "['Leila Arras' 'Franziska Horn' 'Grégoire Montavon' 'Klaus-Robert Müller'\n 'Wojciech Samek']" ]
stat.ML cs.LG
10.7282/t3-t7fe-4a02
1612.07857
null
null
null
null
null
Human Action Attribute Learning From Video Data Using Low-Rank Representations
Representation of human actions as a sequence of human body movements or action attributes enables the development of models for human activity recognition and summarization. We present an extension of the low-rank representation (LRR) model, termed the clustering-aware structure-constrained low-rank representation (CS-LRR) model, for unsupervised learning of human action attributes from video data. Our model is based on the union-of-subspaces (UoS) framework, and integrates spectral clustering into the LRR optimization problem for better subspace clustering results. We lay out an efficient linear alternating direction method to solve the CS-LRR optimization problem. We also introduce a hierarchical subspace clustering approach, termed hierarchical CS-LRR, to learn the attributes without the need for a priori specification of their number. By visualizing and labeling these action attributes, the hierarchical model can be used to semantically summarize long video sequences of human actions at multiple resolutions. A human action or activity can also be uniquely represented as a sequence of transitions from one action attribute to another, which can then be used for human action recognition. We demonstrate the effectiveness of the proposed model for semantic summarization and action recognition through comprehensive experiments on five real-world human action datasets.
[ "Tong Wu, Prudhvi Gurram, Raghuveer M. Rao, and Waheed U. Bajwa" ]
cs.AI cs.LG
null
1612.07896
null
null
http://arxiv.org/pdf/1612.07896v1
2016-12-23T08:03:20Z
2016-12-23T08:03:20Z
A Base Camp for Scaling AI
Modern statistical machine learning (SML) methods share a major limitation with the early approaches to AI: there is no scalable way to adapt them to new domains. Human learning solves this in part by leveraging a rich, shared, updateable world model. Such scalability requires modularity: updating part of the world model should not impact unrelated parts. We have argued that such modularity will require both "correctability" (so that errors can be corrected without introducing new errors) and "interpretability" (so that we can understand what components need correcting). To achieve this, one could attempt to adapt state of the art SML systems to be interpretable and correctable; or one could see how far the simplest possible interpretable, correctable learning methods can take us, and try to control the limitations of SML methods by applying them only where needed. Here we focus on the latter approach and we investigate two main ideas: "Teacher Assisted Learning", which leverages crowd sourcing to learn language; and "Factored Dialog Learning", which factors the process of application development into roles where the language competencies needed are isolated, enabling non-experts to quickly create new applications. We test these ideas in an "Automated Personal Assistant" (APA) setting, with two scenarios: that of detecting user intent from a user-APA dialog; and that of creating a class of event reminder applications, where a non-expert "teacher" can then create specific apps. For the intent detection task, we use a dataset of a thousand labeled utterances from user dialogs with Cortana, and we show that our approach matches state of the art SML methods, but in addition provides full transparency: the whole (editable) model can be summarized on one human-readable page. For the reminder app task, we ran small user studies to verify the efficacy of the approach.
[ "['C. J. C. Burges' 'T. Hart' 'Z. Yang' 'S. Cucerzan' 'R. W. White'\n 'A. Pastusiak' 'J. Lewis']", "C.J.C. Burges, T. Hart, Z. Yang, S. Cucerzan, R.W. White, A.\n Pastusiak, J. Lewis" ]
cs.CL cs.LG
null
1612.0794
null
null
null
null
null
Supervised Opinion Aspect Extraction by Exploiting Past Extraction Results
One of the key tasks of sentiment analysis of product reviews is to extract product aspects or features that users have expressed opinions on. In this work, we focus on using supervised sequence labeling as the base approach to performing the task. Although several extraction methods using sequence labeling methods such as Conditional Random Fields (CRF) and Hidden Markov Models (HMM) have been proposed, we show that this supervised approach can be significantly improved by exploiting the idea of concept sharing across multiple domains. For example, "screen" is an aspect in iPhone, but not only iPhone has a screen, many electronic devices have screens too. When "screen" appears in a review of a new domain (or product), it is likely to be an aspect too. Knowing this information enables us to do much better extraction in the new domain. This paper proposes a novel extraction method exploiting this idea in the context of supervised sequence labeling. Experimental results show that it produces markedly better results than without using the past information.
[ "Lei Shu, Bing Liu, Hu Xu, Annice Kim" ]
null
null
1612.07940
null
null
http://arxiv.org/pdf/1612.07940v1
2016-12-23T11:32:37Z
2016-12-23T11:32:37Z
Supervised Opinion Aspect Extraction by Exploiting Past Extraction Results
One of the key tasks of sentiment analysis of product reviews is to extract product aspects or features that users have expressed opinions on. In this work, we focus on using supervised sequence labeling as the base approach to performing the task. Although several extraction methods using sequence labeling methods such as Conditional Random Fields (CRF) and Hidden Markov Models (HMM) have been proposed, we show that this supervised approach can be significantly improved by exploiting the idea of concept sharing across multiple domains. For example, "screen" is an aspect in iPhone, but not only iPhone has a screen, many electronic devices have screens too. When "screen" appears in a review of a new domain (or product), it is likely to be an aspect too. Knowing this information enables us to do much better extraction in the new domain. This paper proposes a novel extraction method exploiting this idea in the context of supervised sequence labeling. Experimental results show that it produces markedly better results than without using the past information.
[ "['Lei Shu' 'Bing Liu' 'Hu Xu' 'Annice Kim']" ]
cs.LG stat.ML
null
1612.07976
null
null
http://arxiv.org/pdf/1612.07976v2
2016-12-28T02:29:15Z
2016-12-23T14:07:01Z
DeMIAN: Deep Modality Invariant Adversarial Network
Obtaining common representations from different modalities is important in that they are interchangeable with each other in a classification problem. For example, we can train a classifier on image features in the common representations and apply it to the testing of the text features in the representations. Existing multi-modal representation learning methods mainly aim to extract rich information from paired samples and train a classifier by the corresponding labels; however, collecting paired samples and their labels simultaneously involves high labor costs. Addressing paired modal samples without their labels and single modal data with their labels independently is much easier than addressing labeled multi-modal data. To obtain the common representations under such a situation, we propose to make the distributions over different modalities similar in the learned representations, namely modality-invariant representations. In particular, we propose a novel algorithm for modality-invariant representation learning, named Deep Modality Invariant Adversarial Network (DeMIAN), which utilizes the idea of Domain Adaptation (DA). Using the modality-invariant representations learned by DeMIAN, we achieved better classification accuracy than with the state-of-the-art methods, especially for some benchmark datasets of zero-shot learning.
[ "['Kuniaki Saito' 'Yusuke Mukuta' 'Yoshitaka Ushiku' 'Tatsuya Harada']", "Kuniaki Saito, Yusuke Mukuta, Yoshitaka Ushiku, Tatsuya Harada" ]
stat.ML cs.LG
null
1612.07993
null
null
http://arxiv.org/pdf/1612.07993v1
2016-12-23T15:02:54Z
2016-12-23T15:02:54Z
RSSL: Semi-supervised Learning in R
In this paper, we introduce a package for semi-supervised learning research in the R programming language called RSSL. We cover the purpose of the package, the methods it includes and comment on their use and implementation. We then show, using several code examples, how the package can be used to replicate well-known results from the semi-supervised learning literature.
[ "['Jesse H. Krijthe']", "Jesse H. Krijthe" ]
stat.ML cs.LG
null
1612.08082
null
null
http://arxiv.org/pdf/1612.08082v3
2018-07-10T08:16:55Z
2016-12-23T20:29:52Z
Constructing Effective Personalized Policies Using Counterfactual Inference from Biased Data Sets with Many Features
This paper proposes a novel approach for constructing effective personalized policies when the observed data lacks counter-factual information, is biased and possesses many features. The approach is applicable in a wide variety of settings from healthcare to advertising to education to finance. These settings have in common that the decision maker can observe, for each previous instance, an array of features of the instance, the action taken in that instance, and the reward realized -- but not the rewards of actions that were not taken: the counterfactual information. Learning in such settings is made even more difficult because the observed data is typically biased by the existing policy (that generated the data) and because the array of features that might affect the reward in a particular instance -- and hence should be taken into account in deciding on an action in each particular instance -- is often vast. The approach presented here estimates propensity scores for the observed data, infers counterfactuals, identifies a (relatively small) number of features that are (most) relevant for each possible action and instance, and prescribes a policy to be followed. Comparison of the proposed algorithm against the state-of-art algorithm on actual datasets demonstrates that the proposed algorithm achieves a significant improvement in performance.
[ "['Onur Atan' 'William R. Zame' 'Qiaojun Feng' 'Mihaela van der Schaar']", "Onur Atan, William R. Zame, Qiaojun Feng, Mihaela van der Schaar" ]
cs.SI cs.LG physics.soc-ph
null
1612.08102
null
null
http://arxiv.org/pdf/1612.08102v1
2016-12-23T21:20:55Z
2016-12-23T21:20:55Z
On Spectral Analysis of Directed Signed Graphs
It has been shown that the adjacency eigenspace of a network contains key information of its underlying structure. However, there has been no study on spectral analysis of the adjacency matrices of directed signed graphs. In this paper, we derive theoretical approximations of spectral projections from such directed signed networks using matrix perturbation theory. We use the derived theoretical results to study the influences of negative intra cluster and inter cluster directed edges on node spectral projections. We then develop a spectral clustering based graph partition algorithm, SC-DSG, and conduct evaluations on both synthetic and real datasets. Both theoretical analysis and empirical evaluation demonstrate the effectiveness of the proposed algorithm.
[ "['Yuemeng Li' 'Xintao Wu' 'Aidong Lu']", "Yuemeng Li, Xintao Wu, Aidong Lu" ]
cs.CV cs.CL cs.LG
null
1612.08354
null
null
http://arxiv.org/pdf/1612.08354v1
2016-12-26T09:51:18Z
2016-12-26T09:51:18Z
Image-Text Multi-Modal Representation Learning by Adversarial Backpropagation
We present novel method for image-text multi-modal representation learning. In our knowledge, this work is the first approach of applying adversarial learning concept to multi-modal learning and not exploiting image-text pair information to learn multi-modal feature. We only use category information in contrast with most previous methods using image-text pair information for multi-modal embedding. In this paper, we show that multi-modal feature can be achieved without image-text pair information and our method makes more similar distribution with image and text in multi-modal feature space than other methods which use image-text pair information. And we show our multi-modal feature has universal semantic information, even though it was trained for category prediction. Our model is end-to-end backpropagation, intuitive and easily extended to other multi-modal learning work.
[ "Gwangbeen Park, Woobin Im", "['Gwangbeen Park' 'Woobin Im']" ]
cs.LG stat.ML
null
1612.08388
null
null
http://arxiv.org/pdf/1612.08388v1
2016-12-26T14:25:32Z
2016-12-26T14:25:32Z
Clustering Algorithms: A Comparative Approach
Many real-world systems can be studied in terms of pattern recognition tasks, so that proper use (and understanding) of machine learning methods in practical applications becomes essential. While a myriad of classification methods have been proposed, there is no consensus on which methods are more suitable for a given dataset. As a consequence, it is important to comprehensively compare methods in many possible scenarios. In this context, we performed a systematic comparison of 7 well-known clustering methods available in the R language. In order to account for the many possible variations of data, we considered artificial datasets with several tunable properties (number of classes, separation between classes, etc). In addition, we also evaluated the sensitivity of the clustering methods with regard to their parameters configuration. The results revealed that, when considering the default configurations of the adopted methods, the spectral approach usually outperformed the other clustering algorithms. We also found that the default configuration of the adopted implementations was not accurate. In these cases, a simple approach based on random selection of parameters values proved to be a good alternative to improve the performance. All in all, the reported approach provides subsidies guiding the choice of clustering algorithms.
[ "['Mayra Z. Rodriguez' 'Cesar H. Comin' 'Dalcimar Casanova'\n 'Odemir M. Bruno' 'Diego R. Amancio' 'Francisco A. Rodrigues'\n 'Luciano da F. Costa']", "Mayra Z. Rodriguez, Cesar H. Comin, Dalcimar Casanova, Odemir M.\n Bruno, Diego R. Amancio, Francisco A. Rodrigues, Luciano da F. Costa" ]
stat.ML cs.LG q-bio.NC
null
1612.08392
null
null
http://arxiv.org/pdf/1612.08392v1
2016-12-26T14:37:57Z
2016-12-26T14:37:57Z
Multi-Region Neural Representation: A novel model for decoding visual stimuli in human brains
Multivariate Pattern (MVP) classification holds enormous potential for decoding visual stimuli in the human brain by employing task-based fMRI data sets. There is a wide range of challenges in the MVP techniques, i.e. decreasing noise and sparsity, defining effective regions of interest (ROIs), visualizing results, and the cost of brain studies. In overcoming these challenges, this paper proposes a novel model of neural representation, which can automatically detect the active regions for each visual stimulus and then utilize these anatomical regions for visualizing and analyzing the functional activities. Therefore, this model provides an opportunity for neuroscientists to ask this question: what is the effect of a stimulus on each of the detected regions instead of just study the fluctuation of voxels in the manually selected ROIs. Moreover, our method introduces analyzing snapshots of brain image for decreasing sparsity rather than using the whole of fMRI time series. Further, a new Gaussian smoothing method is proposed for removing noise of voxels in the level of ROIs. The proposed method enables us to combine different fMRI data sets for reducing the cost of brain studies. Experimental studies on 4 visual categories (words, consonants, objects and nonsense photos) confirm that the proposed method achieves superior performance to state-of-the-art methods.
[ "['Muhammad Yousefnezhad' 'Daoqiang Zhang']", "Muhammad Yousefnezhad, Daoqiang Zhang" ]
stat.ML astro-ph.IM cs.IT cs.LG math.IT
null
1612.08406
null
null
http://arxiv.org/pdf/1612.08406v2
2017-02-13T22:21:17Z
2016-12-26T15:42:22Z
Correlated signal inference by free energy exploration
The inference of correlated signal fields with unknown correlation structures is of high scientific and technological relevance, but poses significant conceptual and numerical challenges. To address these, we develop the correlated signal inference (CSI) algorithm within information field theory (IFT) and discuss its numerical implementation. To this end, we introduce the free energy exploration (FrEE) strategy for numerical information field theory (NIFTy) applications. The FrEE strategy is to let the mathematical structure of the inference problem determine the dynamics of the numerical solver. FrEE uses the Gibbs free energy formalism for all involved unknown fields and correlation structures without marginalization of nuisance quantities. It thereby avoids the complexity marginalization often impose to IFT equations. FrEE simultaneously solves for the mean and the uncertainties of signal, nuisance, and auxiliary fields, while exploiting any analytically calculable quantity. Finally, FrEE uses a problem specific and self-tuning exploration strategy to swiftly identify the optimal field estimates as well as their uncertainty maps. For all estimated fields, properly weighted posterior samples drawn from their exact, fully non-Gaussian distributions can be generated. Here, we develop the FrEE strategies for the CSI of a normal, a log-normal, and a Poisson log-normal IFT signal inference problem and demonstrate their performances via their NIFTy implementations.
[ "['Torsten A. Enßlin' 'Jakob Knollmüller']", "Torsten A. En{\\ss}lin, Jakob Knollm\\\"uller" ]
stat.ML cs.LG
null
1612.08425
null
null
http://arxiv.org/pdf/1612.08425v2
2016-12-29T16:25:34Z
2016-12-26T18:47:11Z
Unsupervised Learning for Computational Phenotyping
With large volumes of health care data comes the research area of computational phenotyping, making use of techniques such as machine learning to describe illnesses and other clinical concepts from the data itself. The "traditional" approach of using supervised learning relies on a domain expert, and has two main limitations: requiring skilled humans to supply correct labels limits its scalability and accuracy, and relying on existing clinical descriptions limits the sorts of patterns that can be found. For instance, it may fail to acknowledge that a disease treated as a single condition may really have several subtypes with different phenotypes, as seems to be the case with asthma and heart disease. Some recent papers cite successes instead using unsupervised learning. This shows great potential for finding patterns in Electronic Health Records that would otherwise be hidden and that can lead to greater understanding of conditions and treatments. This work implements a method derived strongly from Lasko et al., but implements it in Apache Spark and Python and generalizes it to laboratory time-series data in MIMIC-III. It is released as an open-source tool for exploration, analysis, and visualization, available at https://github.com/Hodapp87/mimic3_phenotyping
[ "Chris Hodapp", "['Chris Hodapp']" ]
math.OC cs.LG cs.NA
10.1109/TSP.2017.2755597
1612.08461
null
null
http://arxiv.org/abs/1612.08461v2
2017-09-22T21:59:46Z
2016-12-27T00:01:13Z
Randomized Block Frank-Wolfe for Convergent Large-Scale Learning
Owing to their low-complexity iterations, Frank-Wolfe (FW) solvers are well suited for various large-scale learning tasks. When block-separable constraints are present, randomized block FW (RB-FW) has been shown to further reduce complexity by updating only a fraction of coordinate blocks per iteration. To circumvent the limitations of existing methods, the present work develops step sizes for RB-FW that enable a flexible selection of the number of blocks to update per iteration while ensuring convergence and feasibility of the iterates. To this end, convergence rates of RB-FW are established through computational bounds on a primal sub-optimality measure and on the duality gap. The novel bounds extend the existing convergence analysis, which only applies to a step-size sequence that does not generally lead to feasible iterates. Furthermore, two classes of step-size sequences that guarantee feasibility of the iterates are also proposed to enhance flexibility in choosing decay rates. The novel convergence results are markedly broadened to encompass also nonconvex objectives, and further assert that RB-FW with exact line-search reaches a stationary point at rate $\mathcal{O}(1/\sqrt{t})$. Performance of RB-FW with different step sizes and number of blocks is demonstrated in two applications, namely charging of electrical vehicles and structural support vector machines. Extensive simulated tests demonstrate the performance improvement of RB-FW relative to existing randomized single-block FW methods.
[ "['Liang Zhang' 'Gang Wang' 'Daniel Romero' 'Georgios B. Giannakis']", "Liang Zhang, Gang Wang, Daniel Romero, Georgios B. Giannakis" ]
cs.LG stat.ML
null
1612.08498
null
null
http://arxiv.org/pdf/1612.08498v1
2016-12-27T04:38:28Z
2016-12-27T04:38:28Z
Steerable CNNs
It has long been recognized that the invariance and equivariance properties of a representation are critically important for success in many vision tasks. In this paper we present Steerable Convolutional Neural Networks, an efficient and flexible class of equivariant convolutional networks. We show that steerable CNNs achieve state of the art results on the CIFAR image classification benchmark. The mathematical theory of steerable representations reveals a type system in which any steerable representation is a composition of elementary feature types, each one associated with a particular kind of symmetry. We show how the parameter cost of a steerable filter bank depends on the types of the input and output features, and show how to use this knowledge to construct CNNs that utilize parameters effectively.
[ "['Taco S. Cohen' 'Max Welling']", "Taco S. Cohen, Max Welling" ]
cs.LG cs.AI stat.ML
10.1109/TKDE.2017.2720168
1612.08544
null
null
http://arxiv.org/abs/1612.08544v2
2017-11-13T17:42:12Z
2016-12-27T09:14:16Z
Theory-guided Data Science: A New Paradigm for Scientific Discovery from Data
Data science models, although successful in a number of commercial domains, have had limited applicability in scientific problems involving complex physical phenomena. Theory-guided data science (TGDS) is an emerging paradigm that aims to leverage the wealth of scientific knowledge for improving the effectiveness of data science models in enabling scientific discovery. The overarching vision of TGDS is to introduce scientific consistency as an essential component for learning generalizable models. Further, by producing scientifically interpretable models, TGDS aims to advance our scientific understanding by discovering novel domain insights. Indeed, the paradigm of TGDS has started to gain prominence in a number of scientific disciplines such as turbulence modeling, material discovery, quantum chemistry, bio-medical science, bio-marker discovery, climate science, and hydrology. In this paper, we formally conceptualize the paradigm of TGDS and present a taxonomy of research themes in TGDS. We describe several approaches for integrating domain knowledge in different research themes using illustrative examples from different disciplines. We also highlight some of the promising avenues of novel research for realizing the full potential of theory-guided data science.
[ "Anuj Karpatne, Gowtham Atluri, James Faghmous, Michael Steinbach,\n Arindam Banerjee, Auroop Ganguly, Shashi Shekhar, Nagiza Samatova, and Vipin\n Kumar", "['Anuj Karpatne' 'Gowtham Atluri' 'James Faghmous' 'Michael Steinbach'\n 'Arindam Banerjee' 'Auroop Ganguly' 'Shashi Shekhar' 'Nagiza Samatova'\n 'Vipin Kumar']" ]
cs.DC cs.LG
null
1612.08608
null
null
http://arxiv.org/pdf/1612.08608v1
2016-12-27T12:40:39Z
2016-12-27T12:40:39Z
ASAP: Asynchronous Approximate Data-Parallel Computation
Emerging workloads, such as graph processing and machine learning are approximate because of the scale of data involved and the stochastic nature of the underlying algorithms. These algorithms are often distributed over multiple machines using bulk-synchronous processing (BSP) or other synchronous processing paradigms such as map-reduce. However, data parallel processing primitives such as repeated barrier and reduce operations introduce high synchronization overheads. Hence, many existing data-processing platforms use asynchrony and staleness to improve data-parallel job performance. Often, these systems simply change the synchronous communication to asynchronous between the worker nodes in the cluster. This improves the throughput of data processing but results in poor accuracy of the final output since different workers may progress at different speeds and process inconsistent intermediate outputs. In this paper, we present ASAP, a model that provides asynchronous and approximate processing semantics for data-parallel computation. ASAP provides fine-grained worker synchronization using NOTIFY-ACK semantics that allows independent workers to run asynchronously. ASAP also provides stochastic reduce that provides approximate but guaranteed convergence to the same result as an aggregated all-reduce. In our results, we show that ASAP can reduce synchronization costs and provides 2-10X speedups in convergence and up to 10X savings in network costs for distributed machine learning applications and provides strong convergence guarantees.
[ "['Asim Kadav' 'Erik Kruus']", "Asim Kadav, Erik Kruus" ]
cs.AI cs.LG stat.ML
null
1612.08633
null
null
http://arxiv.org/pdf/1612.08633v1
2016-12-27T13:52:56Z
2016-12-27T13:52:56Z
A Sparse Nonlinear Classifier Design Using AUC Optimization
AUC (Area under the ROC curve) is an important performance measure for applications where the data is highly imbalanced. Learning to maximize AUC performance is thus an important research problem. Using a max-margin based surrogate loss function, AUC optimization problem can be approximated as a pairwise rankSVM learning problem. Batch learning methods for solving the kernelized version of this problem suffer from scalability and may not result in sparse classifiers. Recent years have witnessed an increased interest in the development of online or single-pass online learning algorithms that design a classifier by maximizing the AUC performance. The AUC performance of nonlinear classifiers, designed using online methods, is not comparable with that of nonlinear classifiers designed using batch learning algorithms on many real-world datasets. Motivated by these observations, we design a scalable algorithm for maximizing AUC performance by greedily adding the required number of basis functions into the classifier model. The resulting sparse classifiers perform faster inference. Our experimental results show that the level of sparsity achievable can be order of magnitude smaller than the Kernel RankSVM model without affecting the AUC performance much.
[ "['Vishal Kakkar' 'Shirish K. Shevade' 'S Sundararajan' 'Dinesh Garg']", "Vishal Kakkar, Shirish K. Shevade, S Sundararajan, Dinesh Garg" ]
stat.ML cs.LG
null
1612.0865
null
null
null
null
null
Reproducible Pattern Recognition Research: The Case of Optimistic SSL
In this paper, we discuss the approaches we took and trade-offs involved in making a paper on a conceptual topic in pattern recognition research fully reproducible. We discuss our definition of reproducibility, the tools used, how the analysis was set up, show some examples of alternative analyses the code enables and discuss our views on reproducibility.
[ "Jesse H. Krijthe and Marco Loog" ]
null
null
1612.08650
null
null
http://arxiv.org/pdf/1612.08650v1
2016-12-27T14:57:22Z
2016-12-27T14:57:22Z
Reproducible Pattern Recognition Research: The Case of Optimistic SSL
In this paper, we discuss the approaches we took and trade-offs involved in making a paper on a conceptual topic in pattern recognition research fully reproducible. We discuss our definition of reproducibility, the tools used, how the analysis was set up, show some examples of alternative analyses the code enables and discuss our views on reproducibility.
[ "['Jesse H. Krijthe' 'Marco Loog']" ]
cs.LG
null
1612.08669
null
null
http://arxiv.org/pdf/1612.08669v1
2016-12-27T16:25:28Z
2016-12-27T16:25:28Z
A Hybrid Both Filter and Wrapper Feature Selection Method for Microarray Classification
Gene expression data is widely used in disease analysis and cancer diagnosis. However, since gene expression data could contain thousands of genes simultaneously, successful microarray classification is rather difficult. Feature selection is an important pre-treatment for any classification process. Selecting a useful gene subset as a classifier not only decreases the computational time and cost, but also increases classification accuracy. In this study, we applied the information gain method as a filter approach, and an improved binary particle swarm optimization as a wrapper approach to implement feature selection; selected gene subsets were used to evaluate the performance of classification. Experimental results show that by employing the proposed method fewer gene subsets needed to be selected and better classification accuracy could be obtained.
[ "['Li-Yeh Chuang' 'Chao-Hsuan Ke' 'Cheng-Hong Yang']", "Li-Yeh Chuang, Chao-Hsuan Ke, and Cheng-Hong Yang" ]