categories
string
doi
string
id
string
year
float64
venue
string
link
string
updated
string
published
string
title
string
abstract
string
authors
list
stat.ML cs.LG
null
1612.08714
null
null
http://arxiv.org/pdf/1612.08714v2
2016-12-30T17:56:48Z
2016-12-27T19:39:23Z
Clustering with Confidence: Finding Clusters with Statistical Guarantees
Clustering is a widely used unsupervised learning method for finding structure in the data. However, the resulting clusters are typically presented without any guarantees on their robustness; slightly changing the used data sample or re-running a clustering algorithm involving some stochastic component may lead to completely different clusters. There is, hence, a need for techniques that can quantify the instability of the generated clusters. In this study, we propose a technique for quantifying the instability of a clustering solution and for finding robust clusters, termed core clusters, which correspond to clusters where the co-occurrence probability of each data item within a cluster is at least $1 - \alpha$. We demonstrate how solving the core clustering problem is linked to finding the largest maximal cliques in a graph. We show that the method can be used with both clustering and classification algorithms. The proposed method is tested on both simulated and real datasets. The results show that the obtained clusters indeed meet the guarantees on robustness.
[ "Andreas Henelius, Kai Puolam\\\"aki, Henrik Bostr\\\"om, Panagiotis\n Papapetrou", "['Andreas Henelius' 'Kai Puolamäki' 'Henrik Boström'\n 'Panagiotis Papapetrou']" ]
cs.LG
10.1109/TASE.2018.2876430
1612.08789
null
null
http://arxiv.org/abs/1612.08789v2
2019-02-01T18:18:21Z
2016-12-28T02:31:22Z
Automatic Composition and Optimization of Multicomponent Predictive Systems With an Extended Auto-WEKA
Composition and parameterization of multicomponent predictive systems (MCPSs) consisting of chains of data transformation steps are a challenging task. Auto-WEKA is a tool to automate the combined algorithm selection and hyperparameter (CASH) optimization problem. In this paper, we extend the CASH problem and Auto-WEKA to support the MCPS, including preprocessing steps for both classification and regression tasks. We define the optimization problem in which the search space consists of suitably parameterized Petri nets forming the sought MCPS solutions. In the experimental analysis, we focus on examining the impact of considerably extending the search space (from approximately 22,000 to 812 billion possible combinations of methods and categorical hyperparameters). In a range of extensive experiments, three different optimization strategies are used to automatically compose MCPSs for 21 publicly available data sets. The diversity of the composed MCPSs found is an indication that fully and automatically exploiting different combinations of data cleaning and preprocessing techniques is possible and highly beneficial for different predictive models. We also present the results on seven data sets from real chemical production processes. Our findings can have a major impact on the development of high-quality predictive models as well as their maintenance and scalability aspects needed in modern applications and deployment scenarios.
[ "['Manuel Martin Salvador' 'Marcin Budka' 'Bogdan Gabrys']", "Manuel Martin Salvador, Marcin Budka, Bogdan Gabrys" ]
cs.LG cs.DS stat.ML
null
1612.08795
null
null
http://arxiv.org/pdf/1612.08795v1
2016-12-28T03:35:59Z
2016-12-28T03:35:59Z
Provable learning of Noisy-or Networks
Many machine learning applications use latent variable models to explain structure in data, whereby visible variables (= coordinates of the given datapoint) are explained as a probabilistic function of some hidden variables. Finding parameters with the maximum likelihood is NP-hard even in very simple settings. In recent years, provably efficient algorithms were nevertheless developed for models with linear structures: topic models, mixture models, hidden markov models, etc. These algorithms use matrix or tensor decomposition, and make some reasonable assumptions about the parameters of the underlying model. But matrix or tensor decomposition seems of little use when the latent variable model has nonlinearities. The current paper shows how to make progress: tensor decomposition is applied for learning the single-layer {\em noisy or} network, which is a textbook example of a Bayes net, and used for example in the classic QMR-DT software for diagnosing which disease(s) a patient may have by observing the symptoms he/she exhibits. The technical novelty here, which should be useful in other settings in future, is analysis of tensor decomposition in presence of systematic error (i.e., where the noise/error is correlated with the signal, and doesn't decrease as number of samples goes to infinity). This requires rethinking all steps of tensor decomposition methods from the ground up. For simplicity our analysis is stated assuming that the network parameters were chosen from a probability distribution but the method seems more generally applicable.
[ "Sanjeev Arora, Rong Ge, Tengyu Ma, Andrej Risteski", "['Sanjeev Arora' 'Rong Ge' 'Tengyu Ma' 'Andrej Risteski']" ]
cs.LG cs.AI cs.NE
null
1612.0881
null
null
null
null
null
The Predictron: End-To-End Learning and Planning
One of the key challenges of artificial intelligence is to learn models that are effective in the context of planning. In this document we introduce the predictron architecture. The predictron consists of a fully abstract model, represented by a Markov reward process, that can be rolled forward multiple "imagined" planning steps. Each forward pass of the predictron accumulates internal rewards and values over multiple planning depths. The predictron is trained end-to-end so as to make these accumulated values accurately approximate the true value function. We applied the predictron to procedurally generated random mazes and a simulator for the game of pool. The predictron yielded significantly more accurate predictions than conventional deep neural network architectures.
[ "David Silver, Hado van Hasselt, Matteo Hessel, Tom Schaul, Arthur\n Guez, Tim Harley, Gabriel Dulac-Arnold, David Reichert, Neil Rabinowitz,\n Andre Barreto, Thomas Degris" ]
null
null
1612.08810
null
null
http://arxiv.org/pdf/1612.08810v3
2017-07-20T09:21:54Z
2016-12-28T06:47:15Z
The Predictron: End-To-End Learning and Planning
One of the key challenges of artificial intelligence is to learn models that are effective in the context of planning. In this document we introduce the predictron architecture. The predictron consists of a fully abstract model, represented by a Markov reward process, that can be rolled forward multiple "imagined" planning steps. Each forward pass of the predictron accumulates internal rewards and values over multiple planning depths. The predictron is trained end-to-end so as to make these accumulated values accurately approximate the true value function. We applied the predictron to procedurally generated random mazes and a simulator for the game of pool. The predictron yielded significantly more accurate predictions than conventional deep neural network architectures.
[ "['David Silver' 'Hado van Hasselt' 'Matteo Hessel' 'Tom Schaul'\n 'Arthur Guez' 'Tim Harley' 'Gabriel Dulac-Arnold' 'David Reichert'\n 'Neil Rabinowitz' 'Andre Barreto' 'Thomas Degris']" ]
stat.ML cs.LG
null
1612.08875
null
null
http://arxiv.org/pdf/1612.08875v3
2019-01-08T11:01:35Z
2016-12-28T13:17:07Z
The Pessimistic Limits and Possibilities of Margin-based Losses in Semi-supervised Learning
Consider a classification problem where we have both labeled and unlabeled data available. We show that for linear classifiers defined by convex margin-based surrogate losses that are decreasing, it is impossible to construct any semi-supervised approach that is able to guarantee an improvement over the supervised classifier measured by this surrogate loss on the labeled and unlabeled data. For convex margin-based loss functions that also increase, we demonstrate safe improvements are possible.
[ "Jesse H. Krijthe and Marco Loog", "['Jesse H. Krijthe' 'Marco Loog']" ]
cs.AI cs.LG cs.RO
null
1612.08967
null
null
http://arxiv.org/pdf/1612.08967v1
2016-12-28T19:53:08Z
2016-12-28T19:53:08Z
Efficient iterative policy optimization
We tackle the issue of finding a good policy when the number of policy updates is limited. This is done by approximating the expected policy reward as a sequence of concave lower bounds which can be efficiently maximized, drastically reducing the number of policy updates required to achieve good performance. We also extend existing methods to negative rewards, enabling the use of control variates.
[ "['Nicolas Le Roux']", "Nicolas Le Roux" ]
stat.ML cs.LG
null
1612.09007
null
null
http://arxiv.org/pdf/1612.09007v1
2016-12-28T23:43:27Z
2016-12-28T23:43:27Z
A Deep Learning Approach To Multiple Kernel Fusion
Kernel fusion is a popular and effective approach for combining multiple features that characterize different aspects of data. Traditional approaches for Multiple Kernel Learning (MKL) attempt to learn the parameters for combining the kernels through sophisticated optimization procedures. In this paper, we propose an alternative approach that creates dense embeddings for data using the kernel similarities and adopts a deep neural network architecture for fusing the embeddings. In order to improve the effectiveness of this network, we introduce the kernel dropout regularization strategy coupled with the use of an expanded set of composition kernels. Experiment results on a real-world activity recognition dataset show that the proposed architecture is effective in fusing kernels and achieves state-of-the-art performance.
[ "Huan Song, Jayaraman J. Thiagarajan, Prasanna Sattigeri, Karthikeyan\n Natesan Ramamurthy, Andreas Spanias", "['Huan Song' 'Jayaraman J. Thiagarajan' 'Prasanna Sattigeri'\n 'Karthikeyan Natesan Ramamurthy' 'Andreas Spanias']" ]
cs.LG cs.AI cs.CV
null
1612.0903
null
null
null
null
null
Meta-Unsupervised-Learning: A supervised approach to unsupervised learning
We introduce a new paradigm to investigate unsupervised learning, reducing unsupervised learning to supervised learning. Specifically, we mitigate the subjectivity in unsupervised decision-making by leveraging knowledge acquired from prior, possibly heterogeneous, supervised learning tasks. We demonstrate the versatility of our framework via comprehensive expositions and detailed experiments on several unsupervised problems such as (a) clustering, (b) outlier detection, and (c) similarity prediction under a common umbrella of meta-unsupervised-learning. We also provide rigorous PAC-agnostic bounds to establish the theoretical foundations of our framework, and show that our framing of meta-clustering circumvents Kleinberg's impossibility theorem for clustering.
[ "Vikas K. Garg and Adam Tauman Kalai" ]
null
null
1612.09030
null
null
http://arxiv.org/pdf/1612.09030v2
2017-01-03T17:34:39Z
2016-12-29T03:20:33Z
Meta-Unsupervised-Learning: A supervised approach to unsupervised learning
We introduce a new paradigm to investigate unsupervised learning, reducing unsupervised learning to supervised learning. Specifically, we mitigate the subjectivity in unsupervised decision-making by leveraging knowledge acquired from prior, possibly heterogeneous, supervised learning tasks. We demonstrate the versatility of our framework via comprehensive expositions and detailed experiments on several unsupervised problems such as (a) clustering, (b) outlier detection, and (c) similarity prediction under a common umbrella of meta-unsupervised-learning. We also provide rigorous PAC-agnostic bounds to establish the theoretical foundations of our framework, and show that our framing of meta-clustering circumvents Kleinberg's impossibility theorem for clustering.
[ "['Vikas K. Garg' 'Adam Tauman Kalai']" ]
math.OC cs.LG stat.ML
null
1612.09034
null
null
http://arxiv.org/pdf/1612.09034v4
2017-05-30T06:20:50Z
2016-12-29T04:25:28Z
Geometric descent method for convex composite minimization
In this paper, we extend the geometric descent method recently proposed by Bubeck, Lee and Singh to tackle nonsmooth and strongly convex composite problems. We prove that our proposed algorithm, dubbed geometric proximal gradient method (GeoPG), converges with a linear rate $(1-1/\sqrt{\kappa})$ and thus achieves the optimal rate among first-order methods, where $\kappa$ is the condition number of the problem. Numerical results on linear regression and logistic regression with elastic net regularization show that GeoPG compares favorably with Nesterov's accelerated proximal gradient method, especially when the problem is ill-conditioned.
[ "Shixiang Chen, Shiqian Ma, Wei Liu", "['Shixiang Chen' 'Shiqian Ma' 'Wei Liu']" ]
cs.LG
null
1612.09057
null
null
http://arxiv.org/pdf/1612.09057v4
2018-09-04T23:18:35Z
2016-12-29T07:26:26Z
Deep Learning and Hierarchal Generative Models
It is argued that deep learning is efficient for data that is generated from hierarchal generative models. Examples of such generative models include wavelet scattering networks, functions of compositional structure, and deep rendering models. Unfortunately so far, for all such models, it is either not rigorously known that they can be learned efficiently, or it is not known that "deep algorithms" are required in order to learn them. We propose a simple family of "generative hierarchal models" which can be efficiently learned and where "deep" algorithm are necessary for learning. Our definition of "deep" algorithms is based on the empirical observation that deep nets necessarily use correlations between features. More formally, we show that in a semi-supervised setting, given access to low-order moments of the labeled data and all of the unlabeled data, it is information theoretically impossible to perform classification while at the same time there is an efficient algorithm, that given all labelled and unlabeled data, perfectly labels all unlabelled data with high probability. For the proof, we use and strengthen the fact that Belief Propagation does not admit a good approximation in terms of linear functions.
[ "['Elchanan Mossel']", "Elchanan Mossel" ]
cs.LG stat.ML
null
1612.09076
null
null
http://arxiv.org/pdf/1612.09076v1
2016-12-29T08:53:20Z
2016-12-29T08:53:20Z
Selecting Bases in Spectral learning of Predictive State Representations via Model Entropy
Predictive State Representations (PSRs) are powerful techniques for modelling dynamical systems, which represent a state as a vector of predictions about future observable events (tests). In PSRs, one of the fundamental problems is the learning of the PSR model of the underlying system. Recently, spectral methods have been successfully used to address this issue by treating the learning problem as the task of computing an singular value decomposition (SVD) over a submatrix of a special type of matrix called the Hankel matrix. Under the assumptions that the rows and columns of the submatrix of the Hankel Matrix are sufficient~(which usually means a very large number of rows and columns, and almost fails in practice) and the entries of the matrix can be estimated accurately, it has been proven that the spectral approach for learning PSRs is statistically consistent and the learned parameters can converge to the true parameters. However, in practice, due to the limit of the computation ability, only a finite set of rows or columns can be chosen to be used for the spectral learning. While different sets of columns usually lead to variant accuracy of the learned model, in this paper, we propose an approach for selecting the set of columns, namely basis selection, by adopting a concept of model entropy to measure the accuracy of the learned model. Experimental results are shown to demonstrate the effectiveness of the proposed approach.
[ "Yunlong Liu and Hexing Zhu", "['Yunlong Liu' 'Hexing Zhu']" ]
stat.AP cs.LG
null
1612.09106
null
null
http://arxiv.org/pdf/1612.09106v3
2017-09-18T08:37:11Z
2016-12-29T11:47:23Z
Sequence-to-point learning with neural networks for nonintrusive load monitoring
Energy disaggregation (a.k.a nonintrusive load monitoring, NILM), a single-channel blind source separation problem, aims to decompose the mains which records the whole house electricity consumption into appliance-wise readings. This problem is difficult because it is inherently unidentifiable. Recent approaches have shown that the identifiability problem could be reduced by introducing domain knowledge into the model. Deep neural networks have been shown to be a promising approach for these problems, but sliding windows are necessary to handle the long sequences which arise in signal processing problems, which raises issues about how to combine predictions from different sliding windows. In this paper, we propose sequence-to-point learning, where the input is a window of the mains and the output is a single point of the target appliance. We use convolutional neural networks to train the model. Interestingly, we systematically show that the convolutional neural networks can inherently learn the signatures of the target appliances, which are automatically added into the model to reduce the identifiability problem. We applied the proposed neural network approaches to real-world household energy data, and show that the methods achieve state-of-the-art performance, improving two standard error measures by 84% and 92%.
[ "Chaoyun Zhang, Mingjun Zhong, Zongzuo Wang, Nigel Goddard, Charles\n Sutton", "['Chaoyun Zhang' 'Mingjun Zhong' 'Zongzuo Wang' 'Nigel Goddard'\n 'Charles Sutton']" ]
cs.LG
null
1612.09122
null
null
http://arxiv.org/pdf/1612.09122v1
2016-12-29T12:29:20Z
2016-12-29T12:29:20Z
Modeling documents with Generative Adversarial Networks
This paper describes a method for using Generative Adversarial Networks to learn distributed representations of natural language documents. We propose a model that is based on the recently proposed Energy-Based GAN, but instead uses a Denoising Autoencoder as the discriminator network. Document representations are extracted from the hidden layer of the discriminator and evaluated both quantitatively and qualitatively.
[ "John Glover", "['John Glover']" ]
cs.LG
null
1612.09147
null
null
http://arxiv.org/pdf/1612.09147v2
2017-01-26T16:44:56Z
2016-12-29T14:02:31Z
Linear Learning with Sparse Data
Linear predictors are especially useful when the data is high-dimensional and sparse. One of the standard techniques used to train a linear predictor is the Averaged Stochastic Gradient Descent (ASGD) algorithm. We present an efficient implementation of ASGD that avoids dense vector operations. We also describe a translation invariant extension called Centered Averaged Stochastic Gradient Descent (CASGD).
[ "['Ofer Dekel']", "Ofer Dekel" ]
cs.SY cs.LG stat.ML
null
1612.09158
null
null
http://arxiv.org/pdf/1612.09158v1
2016-12-29T14:32:51Z
2016-12-29T14:32:51Z
The interplay between system identification and machine learning
Learning from examples is one of the key problems in science and engineering. It deals with function reconstruction from a finite set of direct and noisy samples. Regularization in reproducing kernel Hilbert spaces (RKHSs) is widely used to solve this task and includes powerful estimators such as regularization networks. Recent achievements include the proof of the statistical consistency of these kernel- based approaches. Parallel to this, many different system identification techniques have been developed but the interaction with machine learning does not appear so strong yet. One reason is that the RKHSs usually employed in machine learning do not embed the information available on dynamic systems, e.g. BIBO stability. In addition, in system identification the independent data assumptions routinely adopted in machine learning are never satisfied in practice. This paper provides new results which strengthen the connection between system identification and machine learning. Our starting point is the introduction of RKHSs of dynamic systems. They contain functionals over spaces defined by system inputs and allow to interpret system identification as learning from examples. In both linear and nonlinear settings, it is shown that this perspective permits to derive in a relatively simple way conditions on RKHS stability (i.e. the property of containing only BIBO stable systems or predictors), also facilitating the design of new kernels for system identification. Furthermore, we prove the convergence of the regularized estimator to the optimal predictor under conditions typical of dynamic systems.
[ "['Gianluigi Pillonetto']", "Gianluigi Pillonetto" ]
cs.NE cs.AI cs.LG
null
1612.09205
null
null
http://arxiv.org/pdf/1612.09205v1
2016-12-29T17:14:05Z
2016-12-29T17:14:05Z
Deep neural heart rate variability analysis
Despite of the pain and limited accuracy of blood tests for early recognition of cardiovascular disease, they dominate risk screening and triage. On the other hand, heart rate variability is non-invasive and cheap, but not considered accurate enough for clinical practice. Here, we tackle heart beat interval based classification with deep learning. We introduce an end to end differentiable hybrid architecture, consisting of a layer of biological neuron models of cardiac dynamics (modified FitzHugh Nagumo neurons) and several layers of a standard feed-forward neural network. The proposed model is evaluated on ECGs from 474 stable at-risk (coronary artery disease) patients, and 1172 chest pain patients of an emergency department. We show that it can significantly outperform models based on traditional heart rate variability predictors, as well as approaching or in some cases outperforming clinical blood tests, based only on 60 seconds of inter-beat intervals.
[ "Tamas Madl", "['Tamas Madl']" ]
stat.ML cs.LG
null
1612.09283
null
null
http://arxiv.org/pdf/1612.09283v1
2016-12-29T20:40:52Z
2016-12-29T20:40:52Z
Generalized Intersection Kernel
Following the very recent line of work on the ``generalized min-max'' (GMM) kernel, this study proposes the ``generalized intersection'' (GInt) kernel and the related ``normalized generalized min-max'' (NGMM) kernel. In computer vision, the (histogram) intersection kernel has been popular, and the GInt kernel generalizes it to data which can have both negative and positive entries. Through an extensive empirical classification study on 40 datasets from the UCI repository, we are able to show that this (tuning-free) GInt kernel performs fairly well. The empirical results also demonstrate that the NGMM kernel typically outperforms the GInt kernel. Interestingly, the NGMM kernel has another interpretation --- it is the ``asymmetrically transformed'' version of the GInt kernel, based on the idea of ``asymmetric hashing''. Just like the GMM kernel, the NGMM kernel can be efficiently linearized through (e.g.,) generalized consistent weighted sampling (GCWS), as empirically validated in our study. Owing to the discrete nature of hashed values, it also provides a scheme for approximate near neighbor search.
[ "Ping Li", "['Ping Li']" ]
cs.LG math.OC stat.ML
null
1612.09296
null
null
http://arxiv.org/pdf/1612.09296v3
2018-01-20T02:45:55Z
2016-12-29T20:57:19Z
Symmetry, Saddle Points, and Global Optimization Landscape of Nonconvex Matrix Factorization
We propose a general theory for studying the \xl{landscape} of nonconvex \xl{optimization} with underlying symmetric structures \tz{for a class of machine learning problems (e.g., low-rank matrix factorization, phase retrieval, and deep linear neural networks)}. In specific, we characterize the locations of stationary points and the null space of Hessian matrices \xl{of the objective function} via the lens of invariant groups\removed{for associated optimization problems, including low-rank matrix factorization, phase retrieval, and deep linear neural networks}. As a major motivating example, we apply the proposed general theory to characterize the global \xl{landscape} of the \xl{nonconvex optimization in} low-rank matrix factorization problem. In particular, we illustrate how the rotational symmetry group gives rise to infinitely many nonisolated strict saddle points and equivalent global minima of the objective function. By explicitly identifying all stationary points, we divide the entire parameter space into three regions: ($\cR_1$) the region containing the neighborhoods of all strict saddle points, where the objective has negative curvatures; ($\cR_2$) the region containing neighborhoods of all global minima, where the objective enjoys strong convexity along certain directions; and ($\cR_3$) the complement of the above regions, where the gradient has sufficiently large magnitudes. We further extend our result to the matrix sensing problem. Such global landscape implies strong global convergence guarantees for popular iterative algorithms with arbitrary initial solutions.
[ "['Xingguo Li' 'Junwei Lu' 'Raman Arora' 'Jarvis Haupt' 'Han Liu'\n 'Zhaoran Wang' 'Tuo Zhao']", "Xingguo Li, Junwei Lu, Raman Arora, Jarvis Haupt, Han Liu, Zhaoran\n Wang, Tuo Zhao" ]
cs.LG stat.ML
null
1612.09328
null
null
http://arxiv.org/pdf/1612.09328v3
2017-11-21T16:04:21Z
2016-12-29T22:02:53Z
The Neural Hawkes Process: A Neurally Self-Modulating Multivariate Point Process
Many events occur in the world. Some event types are stochastically excited or inhibited---in the sense of having their probabilities elevated or decreased---by patterns in the sequence of previous events. Discovering such patterns can help us predict which type of event will happen next and when. We model streams of discrete events in continuous time, by constructing a neurally self-modulating multivariate point process in which the intensities of multiple event types evolve according to a novel continuous-time LSTM. This generative model allows past events to influence the future in complex and realistic ways, by conditioning future event intensities on the hidden state of a recurrent neural network that has consumed the stream of past events. Our model has desirable qualitative properties. It achieves competitive likelihood and predictive accuracy on real and synthetic datasets, including under missing-data conditions.
[ "['Hongyuan Mei' 'Jason Eisner']", "Hongyuan Mei and Jason Eisner" ]
cs.CG cs.LG math.ST stat.TH
null
1612.09434
null
null
http://arxiv.org/pdf/1612.09434v1
2016-12-30T09:33:07Z
2016-12-30T09:33:07Z
Data driven estimation of Laplace-Beltrami operator
Approximations of Laplace-Beltrami operators on manifolds through graph Lapla-cians have become popular tools in data analysis and machine learning. These discretized operators usually depend on bandwidth parameters whose tuning remains a theoretical and practical problem. In this paper, we address this problem for the unnormalized graph Laplacian by establishing an oracle inequality that opens the door to a well-founded data-driven procedure for the bandwidth selection. Our approach relies on recent results by Lacour and Massart [LM15] on the so-called Lepski's method.
[ "['Frédéric Chazal' 'Ilaria Giulini' 'Bertrand Michel']", "Fr\\'ed\\'eric Chazal (DATASHAPE), Ilaria Giulini (DATASHAPE), Bertrand\n Michel (LSTA)" ]
cs.LG
null
1612.09438
null
null
http://arxiv.org/pdf/1612.09438v2
2017-01-12T17:26:42Z
2016-12-30T09:57:27Z
Automatic Discoveries of Physical and Semantic Concepts via Association Priors of Neuron Groups
The recent successful deep neural networks are largely trained in a supervised manner. It {\it associates} complex patterns of input samples with neurons in the last layer, which form representations of {\it concepts}. In spite of their successes, the properties of complex patterns associated a learned concept remain elusive. In this work, by analyzing how neurons are associated with concepts in supervised networks, we hypothesize that with proper priors to regulate learning, neural networks can automatically associate neurons in the intermediate layers with concepts that are aligned with real world concepts, when trained only with labels that associate concepts with top level neurons, which is a plausible way for unsupervised learning. We develop a prior to verify the hypothesis and experimentally find the proposed prior help neural networks automatically learn both basic physical concepts at the lower layers, e.g., rotation of filters, and highly semantic concepts at the higher layers, e.g., fine-grained categories of an entry-level category.
[ "['Shuai Li' 'Kui Jia' 'Xiaogang Wang']", "Shuai Li, Kui Jia, Xiaogang Wang" ]
cs.LG cs.AI stat.ML
null
1612.09465
null
null
http://arxiv.org/pdf/1612.09465v1
2016-12-30T11:51:14Z
2016-12-30T11:51:14Z
Adaptive Lambda Least-Squares Temporal Difference Learning
Temporal Difference learning or TD($\lambda$) is a fundamental algorithm in the field of reinforcement learning. However, setting TD's $\lambda$ parameter, which controls the timescale of TD updates, is generally left up to the practitioner. We formalize the $\lambda$ selection problem as a bias-variance trade-off where the solution is the value of $\lambda$ that leads to the smallest Mean Squared Value Error (MSVE). To solve this trade-off we suggest applying Leave-One-Trajectory-Out Cross-Validation (LOTO-CV) to search the space of $\lambda$ values. Unfortunately, this approach is too computationally expensive for most practical applications. For Least Squares TD (LSTD) we show that LOTO-CV can be implemented efficiently to automatically tune $\lambda$ and apply function optimization methods to efficiently search the space of $\lambda$ values. The resulting algorithm, ALLSTD, is parameter free and our experiments demonstrate that ALLSTD is significantly computationally faster than the na\"{i}ve LOTO-CV implementation while achieving similar performance.
[ "['Timothy A. Mann' 'Hugo Penedones' 'Shie Mannor' 'Todd Hester']", "Timothy A. Mann and Hugo Penedones and Shie Mannor and Todd Hester" ]
cs.LG
null
1612.09529
null
null
http://arxiv.org/pdf/1612.09529v1
2016-12-29T05:55:34Z
2016-12-29T05:55:34Z
Linking the Neural Machine Translation and the Prediction of Organic Chemistry Reactions
Finding the main product of a chemical reaction is one of the important problems of organic chemistry. This paper describes a method of applying a neural machine translation model to the prediction of organic chemical reactions. In order to translate 'reactants and reagents' to 'products', a gated recurrent unit based sequence-to-sequence model and a parser to generate input tokens for model from reaction SMILES strings were built. Training sets are composed of reactions from the patent databases, and reactions manually generated applying the elementary reactions in an organic chemistry textbook of Wade. The trained models were tested by examples and problems in the textbook. The prediction process does not need manual encoding of rules (e.g., SMARTS transformations) to predict products, hence it only needs sufficient training reaction sets to learn new types of reactions.
[ "Juno Nam and Jurae Kim", "['Juno Nam' 'Jurae Kim']" ]
stat.AP cs.LG stat.ML
null
1612.09596
null
null
http://arxiv.org/pdf/1612.09596v1
2016-12-30T20:56:41Z
2016-12-30T20:56:41Z
Counterfactual Prediction with Deep Instrumental Variables Networks
We are in the middle of a remarkable rise in the use and capability of artificial intelligence. Much of this growth has been fueled by the success of deep learning architectures: models that map from observables to outputs via multiple layers of latent representations. These deep learning algorithms are effective tools for unstructured prediction, and they can be combined in AI systems to solve complex automated reasoning problems. This paper provides a recipe for combining ML algorithms to solve for causal effects in the presence of instrumental variables -- sources of treatment randomization that are conditionally independent from the response. We show that a flexible IV specification resolves into two prediction tasks that can be solved with deep neural nets: a first-stage network for treatment prediction and a second-stage network whose loss function involves integration over the conditional treatment distribution. This Deep IV framework imposes some specific structure on the stochastic gradient descent routine used for training, but it is general enough that we can take advantage of off-the-shelf ML capabilities and avoid extensive algorithm customization. We outline how to obtain out-of-sample causal validation in order to avoid over-fit. We also introduce schemes for both Bayesian and frequentist inference: the former via a novel adaptation of dropout training, and the latter via a data splitting routine.
[ "Jason Hartford, Greg Lewis, Kevin Leyton-Brown, Matt Taddy", "['Jason Hartford' 'Greg Lewis' 'Kevin Leyton-Brown' 'Matt Taddy']" ]
astro-ph.IM astro-ph.GA astro-ph.HE cs.LG gr-qc
10.1103/PhysRevD.97.044039
1701.00008
null
null
http://arxiv.org/abs/1701.00008v3
2017-11-09T18:50:10Z
2016-12-30T21:00:02Z
Deep Neural Networks to Enable Real-time Multimessenger Astrophysics
Gravitational wave astronomy has set in motion a scientific revolution. To further enhance the science reach of this emergent field, there is a pressing need to increase the depth and speed of the gravitational wave algorithms that have enabled these groundbreaking discoveries. To contribute to this effort, we introduce Deep Filtering, a new highly scalable method for end-to-end time-series signal processing, based on a system of two deep convolutional neural networks, which we designed for classification and regression to rapidly detect and estimate parameters of signals in highly noisy time-series data streams. We demonstrate a novel training scheme with gradually increasing noise levels, and a transfer learning procedure between the two networks. We showcase the application of this method for the detection and parameter estimation of gravitational waves from binary black hole mergers. Our results indicate that Deep Filtering significantly outperforms conventional machine learning techniques, achieves similar performance compared to matched-filtering while being several orders of magnitude faster thus allowing real-time processing of raw big data with minimal resources. More importantly, Deep Filtering extends the range of gravitational wave signals that can be detected with ground-based gravitational wave detectors. This framework leverages recent advances in artificial intelligence algorithms and emerging hardware architectures, such as deep-learning-optimized GPUs, to facilitate real-time searches of gravitational wave sources and their electromagnetic and astro-particle counterparts.
[ "['Daniel George' 'E. A. Huerta']", "Daniel George, E. A. Huerta" ]
cs.LG
null
1701.0016
null
null
null
null
null
NIPS 2016 Tutorial: Generative Adversarial Networks
This report summarizes the tutorial presented by the author at NIPS 2016 on generative adversarial networks (GANs). The tutorial describes: (1) Why generative modeling is a topic worth studying, (2) how generative models work, and how GANs compare to other generative models, (3) the details of how GANs work, (4) research frontiers in GANs, and (5) state-of-the-art image models that combine GANs with other methods. Finally, the tutorial contains three exercises for readers to complete, and the solutions to these exercises.
[ "Ian Goodfellow" ]
null
null
1701.00160
null
null
http://arxiv.org/pdf/1701.00160v4
2017-04-03T21:57:48Z
2016-12-31T19:17:17Z
NIPS 2016 Tutorial: Generative Adversarial Networks
This report summarizes the tutorial presented by the author at NIPS 2016 on generative adversarial networks (GANs). The tutorial describes: (1) Why generative modeling is a topic worth studying, (2) how generative models work, and how GANs compare to other generative models, (3) the details of how GANs work, (4) research frontiers in GANs, and (5) state-of-the-art image models that combine GANs with other methods. Finally, the tutorial contains three exercises for readers to complete, and the solutions to these exercises.
[ "['Ian Goodfellow']" ]
stat.ML cs.LG
null
1701.00167
null
null
http://arxiv.org/pdf/1701.00167v1
2016-12-31T21:17:08Z
2016-12-31T21:17:08Z
Very Fast Kernel SVM under Budget Constraints
In this paper we propose a fast online Kernel SVM algorithm under tight budget constraints. We propose to split the input space using LVQ and train a Kernel SVM in each cluster. To allow for online training, we propose to limit the size of the support vector set of each cluster using different strategies. We show in the experiment that our algorithm is able to achieve high accuracy while having a very high number of samples processed per second both in training and in the evaluation.
[ "David Picard", "['David Picard']" ]
math.OC cs.AI cs.LG cs.SY stat.ML
null
1701.00178
null
null
null
null
null
Lazily Adapted Constant Kinky Inference for Nonparametric Regression and Model-Reference Adaptive Control
Techniques known as Nonlinear Set Membership prediction, Lipschitz Interpolation or Kinky Inference are approaches to machine learning that utilise presupposed Lipschitz properties to compute inferences over unobserved function values. Provided a bound on the true best Lipschitz constant of the target function is known a priori they offer convergence guarantees as well as bounds around the predictions. Considering a more general setting that builds on Hoelder continuity relative to pseudo-metrics, we propose an online method for estimating the Hoelder constant online from function value observations that possibly are corrupted by bounded observational errors. Utilising this to compute adaptive parameters within a kinky inference rule gives rise to a nonparametric machine learning method, for which we establish strong universal approximation guarantees. That is, we show that our prediction rule can learn any continuous function in the limit of increasingly dense data to within a worst-case error bound that depends on the level of observational uncertainty. We apply our method in the context of nonparametric model-reference adaptive control (MRAC). Across a range of simulated aircraft roll-dynamics and performance metrics our approach outperforms recently proposed alternatives that were based on Gaussian processes and RBF-neural networks. For discrete-time systems, we provide guarantees on the tracking success of our learning-based controllers both for the batch and the online learning setting.
[ "Jan-Peter Calliess" ]
cs.LG cs.CR
null
1701.0022
null
null
null
null
null
Classification of Smartphone Users Using Internet Traffic
Today, smartphone devices are owned by a large portion of the population and have become a very popular platform for accessing the Internet. Smartphones provide the user with immediate access to information and services. However, they can easily expose the user to many privacy risks. Applications that are installed on the device and entities with access to the device's Internet traffic can reveal private information about the smartphone user and steal sensitive content stored on the device or transmitted by the device over the Internet. In this paper, we present a method to reveal various demographics and technical computer skills of smartphone users by their Internet traffic records, using machine learning classification models. We implement and evaluate the method on real life data of smartphone users and show that smartphone users can be classified by their gender, smoking habits, software programming experience, and other characteristics.
[ "Andrey Finkelstein, Ron Biton, Rami Puzis, Asaf Shabtai" ]
null
null
1701.00220
null
null
http://arxiv.org/pdf/1701.00220v1
2017-01-01T08:12:49Z
2017-01-01T08:12:49Z
Classification of Smartphone Users Using Internet Traffic
Today, smartphone devices are owned by a large portion of the population and have become a very popular platform for accessing the Internet. Smartphones provide the user with immediate access to information and services. However, they can easily expose the user to many privacy risks. Applications that are installed on the device and entities with access to the device's Internet traffic can reveal private information about the smartphone user and steal sensitive content stored on the device or transmitted by the device over the Internet. In this paper, we present a method to reveal various demographics and technical computer skills of smartphone users by their Internet traffic records, using machine learning classification models. We implement and evaluate the method on real life data of smartphone users and show that smartphone users can be classified by their gender, smoking habits, software programming experience, and other characteristics.
[ "['Andrey Finkelstein' 'Ron Biton' 'Rami Puzis' 'Asaf Shabtai']" ]
cs.LG stat.ML
null
1701.00251
null
null
http://arxiv.org/pdf/1701.00251v1
2017-01-01T15:18:13Z
2017-01-01T15:18:13Z
Outlier Robust Online Learning
We consider the problem of learning from noisy data in practical settings where the size of data is too large to store on a single machine. More challenging, the data coming from the wild may contain malicious outliers. To address the scalability and robustness issues, we present an online robust learning (ORL) approach. ORL is simple to implement and has provable robustness guarantee -- in stark contrast to existing online learning approaches that are generally fragile to outliers. We specialize the ORL approach for two concrete cases: online robust principal component analysis and online linear regression. We demonstrate the efficiency and robustness advantages of ORL through comprehensive simulations and predicting image tags on a large-scale data set. We also discuss extension of the ORL to distributed learning and provide experimental evaluations.
[ "['Jiashi Feng' 'Huan Xu' 'Shie Mannor']", "Jiashi Feng, Huan Xu, Shie Mannor" ]
cs.LG stat.ML
null
1701.00299
null
null
http://arxiv.org/pdf/1701.00299v3
2018-03-05T02:03:00Z
2017-01-02T00:09:14Z
Dynamic Deep Neural Networks: Optimizing Accuracy-Efficiency Trade-offs by Selective Execution
We introduce Dynamic Deep Neural Networks (D2NN), a new type of feed-forward deep neural network that allows selective execution. Given an input, only a subset of D2NN neurons are executed, and the particular subset is determined by the D2NN itself. By pruning unnecessary computation depending on input, D2NNs provide a way to improve computational efficiency. To achieve dynamic selective execution, a D2NN augments a feed-forward deep neural network (directed acyclic graph of differentiable modules) with controller modules. Each controller module is a sub-network whose output is a decision that controls whether other modules can execute. A D2NN is trained end to end. Both regular and controller modules in a D2NN are learnable and are jointly trained to optimize both accuracy and efficiency. Such training is achieved by integrating backpropagation with reinforcement learning. With extensive experiments of various D2NN architectures on image classification tasks, we demonstrate that D2NNs are general and flexible, and can effectively optimize accuracy-efficiency trade-offs.
[ "Lanlan Liu, Jia Deng", "['Lanlan Liu' 'Jia Deng']" ]
cs.LG cs.CV
null
1701.00485
null
null
http://arxiv.org/pdf/1701.00485v2
2017-01-04T13:54:51Z
2017-01-02T04:28:16Z
Two-Bit Networks for Deep Learning on Resource-Constrained Embedded Devices
With the rapid proliferation of Internet of Things and intelligent edge devices, there is an increasing need for implementing machine learning algorithms, including deep learning, on resource-constrained mobile embedded devices with limited memory and computation power. Typical large Convolutional Neural Networks (CNNs) need large amounts of memory and computational power, and cannot be deployed on embedded devices efficiently. We present Two-Bit Networks (TBNs) for model compression of CNNs with edge weights constrained to (-2, -1, 1, 2), which can be encoded with two bits. Our approach can reduce the memory usage and improve computational efficiency significantly while achieving good performance in terms of classification accuracy, thus representing a reasonable tradeoff between model size and performance.
[ "Wenjia Meng, Zonghua Gu, Ming Zhang, Zhaohui Wu", "['Wenjia Meng' 'Zonghua Gu' 'Ming Zhang' 'Zhaohui Wu']" ]
cs.NA cs.LG stat.ML
null
1701.00573
null
null
http://arxiv.org/pdf/1701.00573v3
2017-03-22T22:19:57Z
2017-01-03T03:31:03Z
Robust method for finding sparse solutions to linear inverse problems using an L2 regularization
We analyzed the performance of a biologically inspired algorithm called the Corrected Projections Algorithm (CPA) when a sparseness constraint is required to unambiguously reconstruct an observed signal using atoms from an overcomplete dictionary. By changing the geometry of the estimation problem, CPA gives an analytical expression for a binary variable that indicates the presence or absence of a dictionary atom using an L2 regularizer. The regularized solution can be implemented using an efficient real-time Kalman-filter type of algorithm. The smoother L2 regularization of CPA makes it very robust to noise, and CPA outperforms other methods in identifying known atoms in the presence of strong novel atoms in the signal.
[ "Gonzalo H Otazu", "['Gonzalo H Otazu']" ]
q-bio.QM cs.LG
null
1701.00593
null
null
http://arxiv.org/pdf/1701.00593v2
2017-04-12T23:47:27Z
2017-01-03T06:08:52Z
HLA class I binding prediction via convolutional neural networks
Many biological processes are governed by protein-ligand interactions. One such example is the recognition of self and nonself cells by the immune system. This immune response process is regulated by the major histocompatibility complex (MHC) protein which is encoded by the human leukocyte antigen (HLA) complex. Understanding the binding potential between MHC and peptides can lead to the design of more potent, peptide-based vaccines and immunotherapies for infectious autoimmune diseases. We apply machine learning techniques from the natural language processing (NLP) domain to address the task of MHC-peptide binding prediction. More specifically, we introduce a new distributed representation of amino acids, name HLA-Vec, that can be used for a variety of downstream proteomic machine learning tasks. We then propose a deep convolutional neural network architecture, name HLA-CNN, for the task of HLA class I-peptide binding prediction. Experimental results show combining the new distributed representation with our HLA-CNN architecture achieves state-of-the-art results in the majority of the latest two Immune Epitope Database (IEDB) weekly automated benchmark datasets. We further apply our model to predict binding on the human genome and identify 15 genes with potential for self binding.
[ "['Yeeleng Scott Vang' 'Xiaohui Xie']", "Yeeleng Scott Vang and Xiaohui Xie" ]
cs.LG
null
1701.00597
null
null
http://arxiv.org/pdf/1701.00597v1
2017-01-03T07:07:14Z
2017-01-03T07:07:14Z
Deep Convolutional Neural Networks for Pairwise Causality
Discovering causal models from observational and interventional data is an important first step preceding what-if analysis or counterfactual reasoning. As has been shown before, the direction of pairwise causal relations can, under certain conditions, be inferred from observational data via standard gradient-boosted classifiers (GBC) using carefully engineered statistical features. In this paper we apply deep convolutional neural networks (CNNs) to this problem by plotting attribute pairs as 2-D scatter plots that are fed to the CNN as images. We evaluate our approach on the 'Cause- Effect Pairs' NIPS 2013 Data Challenge. We observe that a weighted ensemble of CNN with the earlier GBC approach yields significant improvement. Further, we observe that when less training data is available, our approach performs better than the GBC based approach suggesting that CNN models pre-trained to determine the direction of pairwise causal direction could have wider applicability in causal discovery and enabling what-if or counterfactual analysis.
[ "Karamjit Singh, Garima Gupta, Lovekesh Vig, Gautam Shroff, and Puneet\n Agarwal", "['Karamjit Singh' 'Garima Gupta' 'Lovekesh Vig' 'Gautam Shroff'\n 'Puneet Agarwal']" ]
cs.LG cs.DC
null
1701.00609
null
null
http://arxiv.org/pdf/1701.00609v1
2017-01-03T09:18:22Z
2017-01-03T09:18:22Z
Akid: A Library for Neural Network Research and Production from a Dataism Approach
Neural networks are a revolutionary but immature technique that is fast evolving and heavily relies on data. To benefit from the newest development and newly available data, we want the gap between research and production as small as possibly. On the other hand, differing from traditional machine learning models, neural network is not just yet another statistic model, but a model for the natural processing engine --- the brain. In this work, we describe a neural network library named {\texttt akid}. It provides higher level of abstraction for entities (abstracted as blocks) in nature upon the abstraction done on signals (abstracted as tensors) by Tensorflow, characterizing the dataism observation that all entities in nature processes input and emit out in some ways. It includes a full stack of software that provides abstraction to let researchers focus on research instead of implementation, while at the same time the developed program can also be put into production seamlessly in a distributed environment, and be production ready. At the top application stack, it provides out-of-box tools for neural network applications. Lower down, akid provides a programming paradigm that lets user easily build customized models. The distributed computing stack handles the concurrency and communication, thus letting models be trained or deployed to a single GPU, multiple GPUs, or a distributed environment without affecting how a model is specified in the programming paradigm stack. Lastly, the distributed deployment stack handles how the distributed computing is deployed, thus decoupling the research prototype environment with the actual production environment, and is able to dynamically allocate computing resources, so development (Devs) and operations (Ops) could be separated. Please refer to http://akid.readthedocs.io/en/latest/ for documentation.
[ "['Shuai Li']", "Shuai Li" ]
stat.ML cs.LG
null
1701.00677
null
null
http://arxiv.org/pdf/1701.00677v1
2017-01-03T12:33:53Z
2017-01-03T12:33:53Z
New Methods of Enhancing Prediction Accuracy in Linear Models with Missing Data
In this paper, prediction for linear systems with missing information is investigated. New methods are introduced to improve the Mean Squared Error (MSE) on the test set in comparison to state-of-the-art methods, through appropriate tuning of Bias-Variance trade-off. First, the use of proposed Soft Weighted Prediction (SWP) algorithm and its efficacy are depicted and compared to previous works for non-missing scenarios. The algorithm is then modified and optimized for missing scenarios. It is shown that controlled over-fitting by suggested algorithms will improve prediction accuracy in various cases. Simulation results approve our heuristics in enhancing the prediction accuracy.
[ "['Mohammad Amin Fakharian' 'Ashkan Esmaeili' 'Farokh Marvasti']", "Mohammad Amin Fakharian, Ashkan Esmaeili, and Farokh Marvasti" ]
cs.LG
10.1109/BigData.2016.7840826
1701.00705
null
null
http://arxiv.org/abs/1701.00705v1
2016-12-29T20:40:42Z
2016-12-29T20:40:42Z
Using Big Data to Enhance the Bosch Production Line Performance: A Kaggle Challenge
This paper describes our approach to the Bosch production line performance challenge run by Kaggle.com. Maximizing the production yield is at the heart of the manufacturing industry. At the Bosch assembly line, data is recorded for products as they progress through each stage. Data science methods are applied to this huge data repository consisting records of tests and measurements made for each component along the assembly line to predict internal failures. We found that it is possible to train a model that predicts which parts are most likely to fail. Thus a smarter failure detection system can be built and the parts tagged likely to fail can be salvaged to decrease operating costs and increase the profit margins.
[ "['Ankita Mangal' 'Nishant Kumar']", "Ankita Mangal and Nishant Kumar" ]
cs.IT cs.LG math.AG math.IT
null
1701.00737
null
null
http://arxiv.org/pdf/1701.00737v2
2017-04-26T01:06:44Z
2017-01-03T16:23:48Z
Deterministic and Probabilistic Conditions for Finite Completability of Low-rank Multi-View Data
We consider the multi-view data completion problem, i.e., to complete a matrix $\mathbf{U}=[\mathbf{U}_1|\mathbf{U}_2]$ where the ranks of $\mathbf{U},\mathbf{U}_1$, and $\mathbf{U}_2$ are given. In particular, we investigate the fundamental conditions on the sampling pattern, i.e., locations of the sampled entries for finite completability of such a multi-view data given the corresponding rank constraints. In contrast with the existing analysis on Grassmannian manifold for a single-view matrix, i.e., conventional matrix completion, we propose a geometric analysis on the manifold structure for multi-view data to incorporate more than one rank constraint. We provide a deterministic necessary and sufficient condition on the sampling pattern for finite completability. We also give a probabilistic condition in terms of the number of samples per column that guarantees finite completability with high probability. Finally, using the developed tools, we derive the deterministic and probabilistic guarantees for unique completability.
[ "['Morteza Ashraphijuo' 'Xiaodong Wang' 'Vaneet Aggarwal']", "Morteza Ashraphijuo and Xiaodong Wang and Vaneet Aggarwal" ]
cs.LG nlin.CD
null
1701.00754
null
null
http://arxiv.org/pdf/1701.00754v1
2017-01-01T05:17:58Z
2017-01-01T05:17:58Z
Using Artificial Neural Networks (ANN) to Control Chaos
Controlling Chaos could be a big factor in getting great stable amounts of energy out of small amounts of not necessarily stable resources. By definition, Chaos is getting huge changes in the system's output due to unpredictable small changes in initial conditions, and that means we could take advantage of this fact and select the proper control system to manipulate system's initial conditions and inputs in general and get a desirable output out of otherwise a Chaotic system. That was accomplished by first building some known chaotic circuit (Chua circuit) and the NI's MultiSim was used to simulate the ANN control system. It was shown that this technique can also be used to stabilize some hard to stabilize electronic systems.
[ "Ibrahim Ighneiwaa, Salwa Hamidatoua, and Fadia Ben Ismaela", "['Ibrahim Ighneiwaa' 'Salwa Hamidatoua' 'Fadia Ben Ismaela']" ]
stat.ML cs.LG math.NA
null
1701.00757
null
null
http://arxiv.org/pdf/1701.00757v1
2017-01-03T17:42:34Z
2017-01-03T17:42:34Z
Clustering Signed Networks with the Geometric Mean of Laplacians
Signed networks allow to model positive and negative relationships. We analyze existing extensions of spectral clustering to signed networks. It turns out that existing approaches do not recover the ground truth clustering in several situations where either the positive or the negative network structures contain no noise. Our analysis shows that these problems arise as existing approaches take some form of arithmetic mean of the Laplacians of the positive and negative part. As a solution we propose to use the geometric mean of the Laplacians of positive and negative part and show that it outperforms the existing approaches. While the geometric mean of matrices is computationally expensive, we show that eigenvectors of the geometric mean can be computed efficiently, leading to a numerical scheme for sparse matrices which is of independent interest.
[ "['Pedro Mercado' 'Francesco Tudisco' 'Matthias Hein']", "Pedro Mercado, Francesco Tudisco and Matthias Hein" ]
cs.LG
null
1701.00831
null
null
http://arxiv.org/pdf/1701.00831v1
2017-01-03T20:54:52Z
2017-01-03T20:54:52Z
Collapsing of dimensionality
We analyze a new approach to Machine Learning coming from a modification of classical regularization networks by casting the process in the time dimension, leading to a sort of collapse of dimensionality in the problem of learning the model parameters. This approach allows the definition of a online learning algorithm that progressively accumulates the knowledge provided in the input trajectory. The regularization principle leads to a solution based on a dynamical system that is paired with a procedure to develop a graph structure that stores the input regularities acquired from the temporal evolution. We report an extensive experimental exploration on the behavior of the parameter of the proposed model and an evaluation on artificial dataset.
[ "Marco Gori, Marco Maggini, Alessandro Rossi", "['Marco Gori' 'Marco Maggini' 'Alessandro Rossi']" ]
cs.CL cs.LG
null
1701.00851
null
null
http://arxiv.org/pdf/1701.00851v1
2017-01-03T22:26:10Z
2017-01-03T22:26:10Z
Unsupervised neural and Bayesian models for zero-resource speech processing
In settings where only unlabelled speech data is available, zero-resource speech technology needs to be developed without transcriptions, pronunciation dictionaries, or language modelling text. There are two central problems in zero-resource speech processing: (i) finding frame-level feature representations which make it easier to discriminate between linguistic units (phones or words), and (ii) segmenting and clustering unlabelled speech into meaningful units. In this thesis, we argue that a combination of top-down and bottom-up modelling is advantageous in tackling these two problems. To address the problem of frame-level representation learning, we present the correspondence autoencoder (cAE), a neural network trained with weak top-down supervision from an unsupervised term discovery system. By combining this top-down supervision with unsupervised bottom-up initialization, the cAE yields much more discriminative features than previous approaches. We then present our unsupervised segmental Bayesian model that segments and clusters unlabelled speech into hypothesized words. By imposing a consistent top-down segmentation while also using bottom-up knowledge from detected syllable boundaries, our system outperforms several others on multi-speaker conversational English and Xitsonga speech data. Finally, we show that the clusters discovered by the segmental Bayesian model can be made less speaker- and gender-specific by using features from the cAE instead of traditional acoustic features. In summary, the different models and systems presented in this thesis show that both top-down and bottom-up modelling can improve representation learning, segmentation and clustering of unlabelled speech data.
[ "Herman Kamper", "['Herman Kamper']" ]
cs.CL cs.LG stat.ML
null
1701.00874
null
null
http://arxiv.org/pdf/1701.00874v4
2017-09-03T21:12:40Z
2017-01-04T00:10:17Z
Neural Probabilistic Model for Non-projective MST Parsing
In this paper, we propose a probabilistic parsing model, which defines a proper conditional probability distribution over non-projective dependency trees for a given sentence, using neural representations as inputs. The neural network architecture is based on bi-directional LSTM-CNNs which benefits from both word- and character-level representations automatically, by using combination of bidirectional LSTM and CNN. On top of the neural network, we introduce a probabilistic structured layer, defining a conditional log-linear model over non-projective trees. We evaluate our model on 17 different datasets, across 14 different languages. By exploiting Kirchhoff's Matrix-Tree Theorem (Tutte, 1984), the partition functions and marginals can be computed efficiently, leading to a straight-forward end-to-end model training procedure via back-propagation. Our parser achieves state-of-the-art parsing performance on nine datasets.
[ "['Xuezhe Ma' 'Eduard Hovy']", "Xuezhe Ma, Eduard Hovy" ]
cs.AI cs.LG cs.LO
10.1007/978-3-319-59271-8_5
1701.00877
null
null
http://arxiv.org/abs/1701.00877v2
2017-01-18T23:39:05Z
2017-01-04T00:45:37Z
On the Usability of Probably Approximately Correct Implication Bases
We revisit the notion of probably approximately correct implication bases from the literature and present a first formulation in the language of formal concept analysis, with the goal to investigate whether such bases represent a suitable substitute for exact implication bases in practical use-cases. To this end, we quantitatively examine the behavior of probably approximately correct implication bases on artificial and real-world data sets and compare their precision and recall with respect to their corresponding exact implication bases. Using a small example, we also provide qualitative insight that implications from probably approximately correct bases can still represent meaningful knowledge from a given data set.
[ "Daniel Borchmann, Tom Hanika, Sergei Obiedkov", "['Daniel Borchmann' 'Tom Hanika' 'Sergei Obiedkov']" ]
stat.ML cs.LG
null
1701.00903
null
null
http://arxiv.org/pdf/1701.00903v1
2017-01-04T05:53:46Z
2017-01-04T05:53:46Z
An Interval-Based Bayesian Generative Model for Human Complex Activity Recognition
Complex activity recognition is challenging due to the inherent uncertainty and diversity of performing a complex activity. Normally, each instance of a complex activity has its own configuration of atomic actions and their temporal dependencies. We propose in this paper an atomic action-based Bayesian model that constructs Allen's interval relation networks to characterize complex activities with structural varieties in a probabilistic generative way: By introducing latent variables from the Chinese restaurant process, our approach is able to capture all possible styles of a particular complex activity as a unique set of distributions over atomic actions and relations. We also show that local temporal dependencies can be retained and are globally consistent in the resulting interval network. Moreover, network structure can be learned from empirical data. A new dataset of complex hand activities has been constructed and made publicly available, which is much larger in size than any existing datasets. Empirical evaluations on benchmark datasets as well as our in-house dataset demonstrate the competitiveness of our approach.
[ "Li Liu and Yongzhong Yang and Lakshmi Narasimhan Govindarajan and Shu\n Wang and Bin Hu and Li Cheng and David S. Rosenblum", "['Li Liu' 'Yongzhong Yang' 'Lakshmi Narasimhan Govindarajan' 'Shu Wang'\n 'Bin Hu' 'Li Cheng' 'David S. Rosenblum']" ]
cs.LG cs.CR cs.CV q-bio.NC stat.ML
10.1162/neco_a_01143
1701.00939
null
null
http://arxiv.org/abs/1701.00939v1
2017-01-04T09:40:09Z
2017-01-04T09:40:09Z
Dense Associative Memory is Robust to Adversarial Inputs
Deep neural networks (DNN) trained in a supervised way suffer from two known problems. First, the minima of the objective function used in learning correspond to data points (also known as rubbish examples or fooling images) that lack semantic similarity with the training data. Second, a clean input can be changed by a small, and often imperceptible for human vision, perturbation, so that the resulting deformed input is misclassified by the network. These findings emphasize the differences between the ways DNN and humans classify patterns, and raise a question of designing learning algorithms that more accurately mimic human perception compared to the existing methods. Our paper examines these questions within the framework of Dense Associative Memory (DAM) models. These models are defined by the energy function, with higher order (higher than quadratic) interactions between the neurons. We show that in the limit when the power of the interaction vertex in the energy function is sufficiently large, these models have the following three properties. First, the minima of the objective function are free from rubbish images, so that each minimum is a semantically meaningful pattern. Second, artificial patterns poised precisely at the decision boundary look ambiguous to human subjects and share aspects of both classes that are separated by that decision boundary. Third, adversarial images constructed by models with small power of the interaction vertex, which are equivalent to DNN with rectified linear units (ReLU), fail to transfer to and fool the models with higher order interactions. This opens up a possibility to use higher order models for detecting and stopping malicious adversarial attacks. The presented results suggest that DAM with higher order energy functions are closer to human visual perception than DNN with ReLUs.
[ "Dmitry Krotov, John J Hopfield", "['Dmitry Krotov' 'John J Hopfield']" ]
cs.LG
null
1701.01
null
null
null
null
null
Online Learning Sensing Matrix and Sparsifying Dictionary Simultaneously for Compressive Sensing
This paper considers the problem of simultaneously learning the Sensing Matrix and Sparsifying Dictionary (SMSD) on a large training dataset. To address the formulated joint learning problem, we propose an online algorithm that consists of a closed-form solution for optimizing the sensing matrix with a fixed sparsifying dictionary and a stochastic method for learning the sparsifying dictionary on a large dataset when the sensing matrix is given. Benefiting from training on a large dataset, the obtained compressive sensing (CS) system by the proposed algorithm yields a much better performance in terms of signal recovery accuracy than the existing ones. The simulation results on natural images demonstrate the effectiveness of the suggested online algorithm compared with the existing methods.
[ "Tao Hong and Zhihui Zhu" ]
null
null
1701.01000
null
null
http://arxiv.org/pdf/1701.01000v4
2018-06-02T16:09:47Z
2017-01-04T13:26:57Z
Online Learning Sensing Matrix and Sparsifying Dictionary Simultaneously for Compressive Sensing
This paper considers the problem of simultaneously learning the Sensing Matrix and Sparsifying Dictionary (SMSD) on a large training dataset. To address the formulated joint learning problem, we propose an online algorithm that consists of a closed-form solution for optimizing the sensing matrix with a fixed sparsifying dictionary and a stochastic method for learning the sparsifying dictionary on a large dataset when the sensing matrix is given. Benefiting from training on a large dataset, the obtained compressive sensing (CS) system by the proposed algorithm yields a much better performance in terms of signal recovery accuracy than the existing ones. The simulation results on natural images demonstrate the effectiveness of the suggested online algorithm compared with the existing methods.
[ "['Tao Hong' 'Zhihui Zhu']" ]
cs.CV cs.LG cs.NE
null
1701.01036
null
null
http://arxiv.org/pdf/1701.01036v2
2017-07-01T13:21:11Z
2017-01-04T14:54:20Z
Demystifying Neural Style Transfer
Neural Style Transfer has recently demonstrated very exciting results which catches eyes in both academia and industry. Despite the amazing results, the principle of neural style transfer, especially why the Gram matrices could represent style remains unclear. In this paper, we propose a novel interpretation of neural style transfer by treating it as a domain adaptation problem. Specifically, we theoretically show that matching the Gram matrices of feature maps is equivalent to minimize the Maximum Mean Discrepancy (MMD) with the second order polynomial kernel. Thus, we argue that the essence of neural style transfer is to match the feature distributions between the style images and the generated images. To further support our standpoint, we experiment with several other distribution alignment methods, and achieve appealing results. We believe this novel interpretation connects these two important research fields, and could enlighten future researches.
[ "Yanghao Li, Naiyan Wang, Jiaying Liu and Xiaodi Hou", "['Yanghao Li' 'Naiyan Wang' 'Jiaying Liu' 'Xiaodi Hou']" ]
cs.LG stat.ML
null
1701.01095
null
null
http://arxiv.org/pdf/1701.01095v3
2017-04-20T20:37:39Z
2017-01-04T18:20:47Z
Estimating Quality in Multi-Objective Bandits Optimization
Many real-world applications are characterized by a number of conflicting performance measures. As optimizing in a multi-objective setting leads to a set of non-dominated solutions, a preference function is required for selecting the solution with the appropriate trade-off between the objectives. The question is: how good do estimations of these objectives have to be in order for the solution maximizing the preference function to remain unchanged? In this paper, we introduce the concept of preference radius to characterize the robustness of the preference function and provide guidelines for controlling the quality of estimations in the multi-objective setting. More specifically, we provide a general formulation of multi-objective optimization under the bandits setting. We show how the preference radius relates to the optimal gap and we use this concept to provide a theoretical analysis of the Thompson sampling algorithm from multivariate normal priors. We finally present experiments to support the theoretical results and highlight the fact that one cannot simply scalarize multi-objective problems into single-objective problems.
[ "['Audrey Durand' 'Christian Gagné']", "Audrey Durand, Christian Gagn\\'e" ]
cs.LG cs.CV
null
1701.01218
null
null
http://arxiv.org/pdf/1701.01218v1
2017-01-05T06:04:53Z
2017-01-05T06:04:53Z
Overlapping Cover Local Regression Machines
We present the Overlapping Domain Cover (ODC) notion for kernel machines, as a set of overlapping subsets of the data that covers the entire training set and optimized to be spatially cohesive as possible. We show how this notion benefit the speed of local kernel machines for regression in terms of both speed while achieving while minimizing the prediction error. We propose an efficient ODC framework, which is applicable to various regression models and in particular reduces the complexity of Twin Gaussian Processes (TGP) regression from cubic to quadratic. Our notion is also applicable to several kernel methods (e.g., Gaussian Process Regression(GPR) and IWTGP regression, as shown in our experiments). We also theoretically justified the idea behind our method to improve local prediction by the overlapping cover. We validated and analyzed our method on three benchmark human pose estimation datasets and interesting findings are discussed.
[ "Mohamed Elhoseiny and Ahmed Elgammal", "['Mohamed Elhoseiny' 'Ahmed Elgammal']" ]
stat.ML cs.LG
10.1007/s00180-017-0742-2
1701.01293
null
null
http://arxiv.org/abs/1701.01293v2
2017-05-04T07:03:28Z
2017-01-05T12:33:19Z
OpenML: An R Package to Connect to the Machine Learning Platform OpenML
OpenML is an online machine learning platform where researchers can easily share data, machine learning tasks and experiments as well as organize them online to work and collaborate more efficiently. In this paper, we present an R package to interface with the OpenML platform and illustrate its usage in combination with the machine learning R package mlr. We show how the OpenML package allows R users to easily search, download and upload data sets and machine learning tasks. Furthermore, we also show how to upload results of experiments, share them with others and download results from other users. Beyond ensuring reproducibility of results, the OpenML platform automates much of the drudge work, speeds up research, facilitates collaboration and increases the users' visibility online.
[ "['Giuseppe Casalicchio' 'Jakob Bossek' 'Michel Lang' 'Dominik Kirchhoff'\n 'Pascal Kerschke' 'Benjamin Hofner' 'Heidi Seibold' 'Joaquin Vanschoren'\n 'Bernd Bischl']", "Giuseppe Casalicchio, Jakob Bossek, Michel Lang, Dominik Kirchhoff,\n Pascal Kerschke, Benjamin Hofner, Heidi Seibold, Joaquin Vanschoren, Bernd\n Bischl" ]
cs.AI cs.GT cs.LG
null
1701.01302
null
null
http://arxiv.org/pdf/1701.01302v3
2017-05-13T08:33:46Z
2017-01-05T13:00:05Z
Toward negotiable reinforcement learning: shifting priorities in Pareto optimal sequential decision-making
Existing multi-objective reinforcement learning (MORL) algorithms do not account for objectives that arise from players with differing beliefs. Concretely, consider two players with different beliefs and utility functions who may cooperate to build a machine that takes actions on their behalf. A representation is needed for how much the machine's policy will prioritize each player's interests over time. Assuming the players have reached common knowledge of their situation, this paper derives a recursion that any Pareto optimal policy must satisfy. Two qualitative observations can be made from the recursion: the machine must (1) use each player's own beliefs in evaluating how well an action will serve that player's utility function, and (2) shift the relative priority it assigns to each player's expected utilities over time, by a factor proportional to how well that player's beliefs predict the machine's inputs. Observation (2) represents a substantial divergence from na\"{i}ve linear utility aggregation (as in Harsanyi's utilitarian theorem, and existing MORL algorithms), which is shown here to be inadequate for Pareto optimal sequential decision-making on behalf of players with different beliefs.
[ "Andrew Critch", "['Andrew Critch']" ]
cs.IR cs.LG stat.ML
null
1701.01325
null
null
http://arxiv.org/pdf/1701.01325v1
2017-01-05T14:14:52Z
2017-01-05T14:14:52Z
Outlier Detection for Text Data : An Extended Version
The problem of outlier detection is extremely challenging in many domains such as text, in which the attribute values are typically non-negative, and most values are zero. In such cases, it often becomes difficult to separate the outliers from the natural variations in the patterns in the underlying data. In this paper, we present a matrix factorization method, which is naturally able to distinguish the anomalies with the use of low rank approximations of the underlying data. Our iterative algorithm TONMF is based on block coordinate descent (BCD) framework. We define blocks over the term-document matrix such that the function becomes solvable. Given most recently updated values of other matrix blocks, we always update one block at a time to its optimal. Our approach has significant advantages over traditional methods for text outlier detection. Finally, we present experimental results illustrating the effectiveness of our method over competing methods.
[ "['Ramakrishnan Kannan' 'Hyenkyun Woo' 'Charu C. Aggarwal' 'Haesun Park']", "Ramakrishnan Kannan, Hyenkyun Woo, Charu C. Aggarwal, Haesun Park" ]
cs.NE cs.AI cs.LG physics.chem-ph stat.ML
null
1701.01329
null
null
http://arxiv.org/pdf/1701.01329v1
2017-01-05T14:28:34Z
2017-01-05T14:28:34Z
Generating Focussed Molecule Libraries for Drug Discovery with Recurrent Neural Networks
In de novo drug design, computational strategies are used to generate novel molecules with good affinity to the desired biological target. In this work, we show that recurrent neural networks can be trained as generative models for molecular structures, similar to statistical language models in natural language processing. We demonstrate that the properties of the generated molecules correlate very well with the properties of the molecules used to train the model. In order to enrich libraries with molecules active towards a given biological target, we propose to fine-tune the model with small sets of molecules, which are known to be active against that target. Against Staphylococcus aureus, the model reproduced 14% of 6051 hold-out test molecules that medicinal chemists designed, whereas against Plasmodium falciparum (Malaria) it reproduced 28% of 1240 test molecules. When coupled with a scoring function, our model can perform the complete de novo drug design cycle to generate large sets of novel molecules for drug discovery.
[ "Marwin H.S. Segler, Thierry Kogej, Christian Tyrchan, Mark P. Waller", "['Marwin H. S. Segler' 'Thierry Kogej' 'Christian Tyrchan'\n 'Mark P. Waller']" ]
cs.LG
null
1701.01358
null
null
http://arxiv.org/pdf/1701.01358v1
2017-01-05T15:40:44Z
2017-01-05T15:40:44Z
NeuroRule: A Connectionist Approach to Data Mining
Classification, which involves finding rules that partition a given data set into disjoint groups, is one class of data mining problems. Approaches proposed so far for mining classification rules for large databases are mainly decision tree based symbolic learning methods. The connectionist approach based on neural networks has been thought not well suited for data mining. One of the major reasons cited is that knowledge generated by neural networks is not explicitly represented in the form of rules suitable for verification or interpretation by humans. This paper examines this issue. With our newly developed algorithms, rules which are similar to, or more concise than those generated by the symbolic methods can be extracted from the neural networks. The data mining process using neural networks with the emphasis on rule extraction is described. Experimental results and comparison with previously published works are presented.
[ "['Hongjun Lu' 'Rudy Setiono' 'Huan Liu']", "Hongjun Lu and Rudy Setiono and Huan Liu" ]
cs.DS cs.LG math.NA stat.ML
null
1701.01394
null
null
http://arxiv.org/pdf/1701.01394v2
2018-03-30T00:51:22Z
2017-01-05T17:31:16Z
On spectral partitioning of signed graphs
We argue that the standard graph Laplacian is preferable for spectral partitioning of signed graphs compared to the signed Laplacian. Simple examples demonstrate that partitioning based on signs of components of the leading eigenvectors of the signed Laplacian may be meaningless, in contrast to partitioning based on the Fiedler vector of the standard graph Laplacian for signed graphs. We observe that negative eigenvalues are beneficial for spectral partitioning of signed graphs, making the Fiedler vector easier to compute.
[ "Andrew V. Knyazev", "['Andrew V. Knyazev']" ]
cs.AI cs.LG cs.RO
10.1109/IECON.2016.7793388
1701.01497
null
null
http://arxiv.org/abs/1701.01497v1
2017-01-05T23:01:08Z
2017-01-05T23:01:08Z
Learning local trajectories for high precision robotic tasks : application to KUKA LBR iiwa Cartesian positioning
To ease the development of robot learning in industry, two conditions need to be fulfilled. Manipulators must be able to learn high accuracy and precision tasks while being safe for workers in the factory. In this paper, we extend previously submitted work which consists in rapid learning of local high accuracy behaviors. By exploration and regression, linear and quadratic models are learnt for respectively the dynamics and cost function. Iterative Linear Quadratic Gaussian Regulator combined with cost quadratic regression can converge rapidly in the final stages towards high accuracy behavior as the cost function is modelled quite precisely. In this paper, both a different cost function and a second order improvement method are implemented within this framework. We also propose an analysis of the algorithm parameters through simulation for a positioning task. Finally, an experimental validation on a KUKA LBR iiwa robot is carried out. This collaborative robot manipulator can be easily programmed into safety mode, which makes it qualified for the second industry constraint stated above.
[ "Joris Guerin, Olivier Gibaru, Eric Nyiri and Stephane Thiery", "['Joris Guerin' 'Olivier Gibaru' 'Eric Nyiri' 'Stephane Thiery']" ]
cs.LG cs.DS math.OC stat.ML
null
1701.01722
null
null
http://arxiv.org/pdf/1701.01722v3
2017-09-18T01:04:08Z
2017-01-06T18:43:53Z
Follow the Compressed Leader: Faster Online Learning of Eigenvectors and Faster MMWU
The online problem of computing the top eigenvector is fundamental to machine learning. In both adversarial and stochastic settings, previous results (such as matrix multiplicative weight update, follow the regularized leader, follow the compressed leader, block power method) either achieve optimal regret but run slow, or run fast at the expense of loosing a $\sqrt{d}$ factor in total regret where $d$ is the matrix dimension. We propose a $\textit{follow-the-compressed-leader (FTCL)}$ framework which achieves optimal regret without sacrificing the running time. Our idea is to "compress" the matrix strategy to dimension 3 in the adversarial setting, or dimension 1 in the stochastic setting. These respectively resolve two open questions regarding the design of optimal and efficient algorithms for the online eigenvector problem.
[ "['Zeyuan Allen-Zhu' 'Yuanzhi Li']", "Zeyuan Allen-Zhu and Yuanzhi Li" ]
cs.LG
null
1701.01887
null
null
http://arxiv.org/pdf/1701.01887v1
2017-01-07T21:44:04Z
2017-01-07T21:44:04Z
Deep Learning for Time-Series Analysis
In many real-world application, e.g., speech recognition or sleep stage classification, data are captured over the course of time, constituting a Time-Series. Time-Series often contain temporal dependencies that cause two otherwise identical points of time to belong to different classes or predict different behavior. This characteristic generally increases the difficulty of analysing them. Existing techniques often depended on hand-crafted features that were expensive to create and required expert knowledge of the field. With the advent of Deep Learning new models of unsupervised learning of features for Time-series analysis and forecast have been developed. Such new developments are the topic of this paper: a review of the main Deep Learning techniques is presented, and some applications on Time-Series analysis are summaried. The results make it clear that Deep Learning has a lot to contribute to the field.
[ "John Cristian Borges Gamboa", "['John Cristian Borges Gamboa']" ]
cs.LG stat.AP
null
1701.01917
null
null
http://arxiv.org/pdf/1701.01917v1
2017-01-08T06:11:34Z
2017-01-08T06:11:34Z
See the Near Future: A Short-Term Predictive Methodology to Traffic Load in ITS
The Intelligent Transportation System (ITS) targets to a coordinated traffic system by applying the advanced wireless communication technologies for road traffic scheduling. Towards an accurate road traffic control, the short-term traffic forecasting to predict the road traffic at the particular site in a short period is often useful and important. In existing works, Seasonal Autoregressive Integrated Moving Average (SARIMA) model is a popular approach. The scheme however encounters two challenges: 1) the analysis on related data is insufficient whereas some important features of data may be neglected; and 2) with data presenting different features, it is unlikely to have one predictive model that can fit all situations. To tackle above issues, in this work, we develop a hybrid model to improve accuracy of SARIMA. In specific, we first explore the autocorrelation and distribution features existed in traffic flow to revise structure of the time series model. Based on the Gaussian distribution of traffic flow, a hybrid model with a Bayesian learning algorithm is developed which can effectively expand the application scenarios of SARIMA. We show the efficiency and accuracy of our proposal using both analysis and experimental studies. Using the real-world trace data, we show that the proposed predicting approach can achieve satisfactory performance in practice.
[ "['Xun Zhou' 'Changle Li' 'Zhe Liu' 'Tom H. Luan' 'Zhifang Miao' 'Lina Zhu'\n 'Lei Xiong']", "Xun Zhou, Changle Li, Zhe Liu, Tom H. Luan, Zhifang Miao, Lina Zhu and\n Lei Xiong" ]
cs.LG
10.1007/s10618-020-00691-y
1701.02026
null
null
http://arxiv.org/abs/1701.02026v3
2019-05-18T15:10:29Z
2017-01-08T22:25:04Z
Large-scale network motif analysis using compression
We introduce a new method for finding network motifs: interesting or informative subgraph patterns in a network. Subgraphs are motifs when their frequency in the data is high compared to the expected frequency under a null model. To compute this expectation, a full or approximate count of the occurrences of a motif is normally repeated on as many as 1000 random graphs sampled from the null model; a prohibitively expensive step. We use ideas from the Minimum Description Length (MDL) literature to define a new measure of motif relevance. With our method, samples from the null model are not required. Instead we compute the probability of the data under the null model and compare this to the probability under a specially designed alternative model. With this new relevance test, we can search for motifs by random sampling, rather than requiring an accurate count of all instances of a motif. This allows motif analysis to scale to networks with billions of links.
[ "Peter Bloem and Steven de Rooij", "['Peter Bloem' 'Steven de Rooij']" ]
stat.ML cs.LG
null
1701.02046
null
null
http://arxiv.org/pdf/1701.02046v2
2017-03-09T17:25:16Z
2017-01-09T01:20:55Z
Tunable GMM Kernels
The recently proposed "generalized min-max" (GMM) kernel can be efficiently linearized, with direct applications in large-scale statistical learning and fast near neighbor search. The linearized GMM kernel was extensively compared in with linearized radial basis function (RBF) kernel. On a large number of classification tasks, the tuning-free GMM kernel performs (surprisingly) well compared to the best-tuned RBF kernel. Nevertheless, one would naturally expect that the GMM kernel ought to be further improved if we introduce tuning parameters. In this paper, we study three simple constructions of tunable GMM kernels: (i) the exponentiated-GMM (or eGMM) kernel, (ii) the powered-GMM (or pGMM) kernel, and (iii) the exponentiated-powered-GMM (epGMM) kernel. The pGMM kernel can still be efficiently linearized by modifying the original hashing procedure for the GMM kernel. On about 60 publicly available classification datasets, we verify that the proposed tunable GMM kernels typically improve over the original GMM kernel. On some datasets, the improvements can be astonishingly significant. For example, on 11 popular datasets which were used for testing deep learning algorithms and tree methods, our experiments show that the proposed tunable GMM kernels are strong competitors to trees and deep nets. The previous studies developed tree methods including "abc-robust-logitboost" and demonstrated the excellent performance on those 11 datasets (and other datasets), by establishing the second-order tree-split formula and new derivatives for multi-class logistic loss. Compared to tree methods like "abc-robust-logitboost" (which are slow and need substantial model sizes), the tunable GMM kernels produce largely comparable results.
[ "Ping Li", "['Ping Li']" ]
cs.LG cs.AI stat.ML
null
1701.02058
null
null
http://arxiv.org/pdf/1701.02058v1
2017-01-09T03:49:26Z
2017-01-09T03:49:26Z
Coupled Compound Poisson Factorization
We present a general framework, the coupled compound Poisson factorization (CCPF), to capture the missing-data mechanism in extremely sparse data sets by coupling a hierarchical Poisson factorization with an arbitrary data-generating model. We derive a stochastic variational inference algorithm for the resulting model and, as examples of our framework, implement three different data-generating models---a mixture model, linear regression, and factor analysis---to robustly model non-random missing data in the context of clustering, prediction, and matrix factorization. In all three cases, we test our framework against models that ignore the missing-data mechanism on large scale studies with non-random missing data, and we show that explicitly modeling the missing-data mechanism substantially improves the quality of the results, as measured using data log likelihood on a held-out test set.
[ "Mehmet E. Basbug, Barbara E. Engelhardt", "['Mehmet E. Basbug' 'Barbara E. Engelhardt']" ]
stat.ML cs.LG q-bio.NC
null
1701.02133
null
null
http://arxiv.org/pdf/1701.02133v1
2017-01-09T11:06:39Z
2017-01-09T11:06:39Z
Deep driven fMRI decoding of visual categories
Deep neural networks have been developed drawing inspiration from the brain visual pathway, implementing an end-to-end approach: from image data to video object classes. However building an fMRI decoder with the typical structure of Convolutional Neural Network (CNN), i.e. learning multiple level of representations, seems impractical due to lack of brain data. As a possible solution, this work presents the first hybrid fMRI and deep features decoding approach: collected fMRI and deep learnt representations of video object classes are linked together by means of Kernel Canonical Correlation Analysis. In decoding, this allows exploiting the discriminatory power of CNN by relating the fMRI representation to the last layer of CNN (fc7). We show the effectiveness of embedding fMRI data onto a subspace related to deep features in distinguishing semantic visual categories based solely on brain imaging data.
[ "['Michele Svanera' 'Sergio Benini' 'Gal Raz' 'Talma Hendler'\n 'Rainer Goebel' 'Giancarlo Valente']", "Michele Svanera, Sergio Benini, Gal Raz, Talma Hendler, Rainer Goebel,\n and Giancarlo Valente" ]
cs.CR cs.LG
null
1701.02145
null
null
http://arxiv.org/pdf/1701.02145v1
2017-01-09T11:46:58Z
2017-01-09T11:46:58Z
Shallow and Deep Networks Intrusion Detection System: A Taxonomy and Survey
Intrusion detection has attracted a considerable interest from researchers and industries. The community, after many years of research, still faces the problem of building reliable and efficient IDS that are capable of handling large quantities of data, with changing patterns in real time situations. The work presented in this manuscript classifies intrusion detection systems (IDS). Moreover, a taxonomy and survey of shallow and deep networks intrusion detection systems is presented based on previous and current works. This taxonomy and survey reviews machine learning techniques and their performance in detecting anomalies. Feature selection which influences the effectiveness of machine learning (ML) IDS is discussed to explain the role of feature selection in the classification and training phase of ML IDS. Finally, a discussion of the false and true positive alarm rates is presented to help researchers model reliable and efficient machine learning based intrusion detection systems.
[ "['Elike Hodo' 'Xavier Bellekens' 'Andrew Hamilton' 'Christos Tachtatzis'\n 'Robert Atkinson']", "Elike Hodo, Xavier Bellekens, Andrew Hamilton, Christos Tachtatzis and\n Robert Atkinson" ]
cs.PL cs.LG
null
1701.02284
null
null
http://arxiv.org/pdf/1701.02284v1
2017-01-09T18:02:13Z
2017-01-09T18:02:13Z
DeepDSL: A Compilation-based Domain-Specific Language for Deep Learning
In recent years, Deep Learning (DL) has found great success in domains such as multimedia understanding. However, the complex nature of multimedia data makes it difficult to develop DL-based software. The state-of-the art tools, such as Caffe, TensorFlow, Torch7, and CNTK, while are successful in their applicable domains, are programming libraries with fixed user interface, internal representation, and execution environment. This makes it difficult to implement portable and customized DL applications. In this paper, we present DeepDSL, a domain specific language (DSL) embedded in Scala, that compiles deep networks written in DeepDSL to Java source code. Deep DSL provides (1) intuitive constructs to support compact encoding of deep networks; (2) symbolic gradient derivation of the networks; (3) static analysis for memory consumption and error detection; and (4) DSL-level optimization to improve memory and runtime efficiency. DeepDSL programs are compiled into compact, efficient, customizable, and portable Java source code, which operates the CUDA and CUDNN interfaces running on Nvidia GPU via a Java Native Interface (JNI) library. We evaluated DeepDSL with a number of popular DL networks. Our experiments show that the compiled programs have very competitive runtime performance and memory efficiency compared to the existing libraries.
[ "Tian Zhao, Xiaobing Huang, Yu Cao", "['Tian Zhao' 'Xiaobing Huang' 'Yu Cao']" ]
cs.LG stat.ML
null
1701.02291
null
null
http://arxiv.org/pdf/1701.02291v2
2017-01-12T07:44:17Z
2017-01-09T18:29:07Z
QuickNet: Maximizing Efficiency and Efficacy in Deep Architectures
We present QuickNet, a fast and accurate network architecture that is both faster and significantly more accurate than other fast deep architectures like SqueezeNet. Furthermore, it uses less parameters than previous networks, making it more memory efficient. We do this by making two major modifications to the reference Darknet model (Redmon et al, 2015): 1) The use of depthwise separable convolutions and 2) The use of parametric rectified linear units. We make the observation that parametric rectified linear units are computationally equivalent to leaky rectified linear units at test time and the observation that separable convolutions can be interpreted as a compressed Inception network (Chollet, 2016). Using these observations, we derive a network architecture, which we call QuickNet, that is both faster and more accurate than previous models. Our architecture provides at least four major advantages: (1) A smaller model size, which is more tenable on memory constrained systems; (2) A significantly faster network which is more tenable on computationally constrained systems; (3) A high accuracy of 95.7 percent on the CIFAR-10 Dataset which outperforms all but one result published so far, although we note that our works are orthogonal approaches and can be combined (4) Orthogonality to previous model compression approaches allowing for further speed gains to be realized.
[ "['Tapabrata Ghosh']", "Tapabrata Ghosh" ]
math.AC cs.CC cs.DM cs.LG math.CO
null
1701.02302
null
null
http://arxiv.org/pdf/1701.02302v3
2017-04-06T07:30:15Z
2017-01-09T18:58:27Z
A Homological Theory of Functions
In computational complexity, a complexity class is given by a set of problems or functions, and a basic challenge is to show separations of complexity classes $A \not= B$ especially when $A$ is known to be a subset of $B$. In this paper we introduce a homological theory of functions that can be used to establish complexity separations, while also providing other interesting consequences. We propose to associate a topological space $S_A$ to each class of functions $A$, such that, to separate complexity classes $A \subseteq B'$, it suffices to observe a change in "the number of holes", i.e. homology, in $S_A$ as a subclass $B$ of $B'$ is added to $A$. In other words, if the homologies of $S_A$ and $S_{A \cup B}$ are different, then $A \not= B'$. We develop the underlying theory of functions based on combinatorial and homological commutative algebra and Stanley-Reisner theory, and recover Minsky and Papert's 1969 result that parity cannot be computed by nonmaximal degree polynomial threshold functions. In the process, we derive a "maximal principle" for polynomial threshold functions that is used to extend this result further to arbitrary symmetric functions. A surprising coincidence is demonstrated, where the maximal dimension of "holes" in $S_A$ upper bounds the VC dimension of $A$, with equality for common computational cases such as the class of polynomial threshold functions or the class of linear functionals in $\mathbb F_2$, or common algebraic cases such as when the Stanley-Reisner ring of $S_A$ is Cohen-Macaulay. As another interesting application of our theory, we prove a result that a priori has nothing to do with complexity separation: it characterizes when a vector subspace intersects the positive cone, in terms of homological conditions. By analogy to Farkas' result doing the same with *linear conditions*, we call our theorem the Homological Farkas Lemma.
[ "Greg Yang", "['Greg Yang']" ]
cs.LG
null
1701.02377
null
null
http://arxiv.org/pdf/1701.02377v1
2017-01-09T22:29:08Z
2017-01-09T22:29:08Z
The principle of cognitive action - Preliminary experimental analysis
In this document we shows a first implementation and some preliminary results of a new theory, facing Machine Learning problems in the frameworks of Classical Mechanics and Variational Calculus. We give a general formulation of the problem and then we studies basic behaviors of the model on simple practical implementations.
[ "Marco Gori, Marco Maggini, Alessandro Rossi", "['Marco Gori' 'Marco Maggini' 'Alessandro Rossi']" ]
stat.ML cs.LG
null
1701.02386
null
null
http://arxiv.org/pdf/1701.02386v2
2017-05-24T11:45:00Z
2017-01-09T23:19:28Z
AdaGAN: Boosting Generative Models
Generative Adversarial Networks (GAN) (Goodfellow et al., 2014) are an effective method for training generative models of complex data such as natural images. However, they are notoriously hard to train and can suffer from the problem of missing modes where the model is not able to produce examples in certain regions of the space. We propose an iterative procedure, called AdaGAN, where at every step we add a new component into a mixture model by running a GAN algorithm on a reweighted sample. This is inspired by boosting algorithms, where many potentially weak individual predictors are greedily aggregated to form a strong composite predictor. We prove that such an incremental procedure leads to convergence to the true distribution in a finite number of steps if each step is optimal, and convergence at an exponential rate otherwise. We also illustrate experimentally that this procedure addresses the problem of missing modes.
[ "Ilya Tolstikhin, Sylvain Gelly, Olivier Bousquet, Carl-Johann\n Simon-Gabriel and Bernhard Sch\\\"olkopf", "['Ilya Tolstikhin' 'Sylvain Gelly' 'Olivier Bousquet'\n 'Carl-Johann Simon-Gabriel' 'Bernhard Schölkopf']" ]
cs.LG cs.AI
null
1701.02392
null
null
http://arxiv.org/pdf/1701.02392v1
2017-01-09T23:36:05Z
2017-01-09T23:36:05Z
Reinforcement Learning via Recurrent Convolutional Neural Networks
Deep Reinforcement Learning has enabled the learning of policies for complex tasks in partially observable environments, without explicitly learning the underlying model of the tasks. While such model-free methods achieve considerable performance, they often ignore the structure of task. We present a natural representation of to Reinforcement Learning (RL) problems using Recurrent Convolutional Neural Networks (RCNNs), to better exploit this inherent structure. We define 3 such RCNNs, whose forward passes execute an efficient Value Iteration, propagate beliefs of state in partially observable environments, and choose optimal actions respectively. Backpropagating gradients through these RCNNs allows the system to explicitly learn the Transition Model and Reward Function associated with the underlying MDP, serving as an elegant alternative to classical model-based RL. We evaluate the proposed algorithms in simulation, considering a robot planning problem. We demonstrate the capability of our framework to reduce the cost of replanning, learn accurate MDP models, and finally re-plan with learnt models to achieve near-optimal policies.
[ "['Tanmay Shankar' 'Santosha K. Dwivedy' 'Prithwijit Guha']", "Tanmay Shankar, Santosha K. Dwivedy, Prithwijit Guha" ]
cs.LG math.NA stat.ML
10.1016/j.jcp.2017.07.050
1701.0244
null
null
null
null
null
Machine Learning of Linear Differential Equations using Gaussian Processes
This work leverages recent advances in probabilistic machine learning to discover conservation laws expressed by parametric linear equations. Such equations involve, but are not limited to, ordinary and partial differential, integro-differential, and fractional order operators. Here, Gaussian process priors are modified according to the particular form of such operators and are employed to infer parameters of the linear equations from scarce and possibly noisy observations. Such observations may come from experiments or "black-box" computer simulations.
[ "Maziar Raissi and George Em. Karniadakis" ]
null
null
1701.02440
null
null
http://arxiv.org/abs/1701.02440v1
2017-01-10T05:14:22Z
2017-01-10T05:14:22Z
Machine Learning of Linear Differential Equations using Gaussian Processes
This work leverages recent advances in probabilistic machine learning to discover conservation laws expressed by parametric linear equations. Such equations involve, but are not limited to, ordinary and partial differential, integro-differential, and fractional order operators. Here, Gaussian process priors are modified according to the particular form of such operators and are employed to infer parameters of the linear equations from scarce and possibly noisy observations. Such observations may come from experiments or "black-box" computer simulations.
[ "['Maziar Raissi' 'George Em. Karniadakis']" ]
cs.CL cs.AI cs.CV cs.LG
null
1701.02477
null
null
http://arxiv.org/pdf/1701.02477v1
2017-01-10T08:47:56Z
2017-01-10T08:47:56Z
Multi-task Learning Of Deep Neural Networks For Audio Visual Automatic Speech Recognition
Multi-task learning (MTL) involves the simultaneous training of two or more related tasks over shared representations. In this work, we apply MTL to audio-visual automatic speech recognition(AV-ASR). Our primary task is to learn a mapping between audio-visual fused features and frame labels obtained from acoustic GMM/HMM model. This is combined with an auxiliary task which maps visual features to frame labels obtained from a separate visual GMM/HMM model. The MTL model is tested at various levels of babble noise and the results are compared with a base-line hybrid DNN-HMM AV-ASR model. Our results indicate that MTL is especially useful at higher level of noise. Compared to base-line, upto 7\% relative improvement in WER is reported at -3 SNR dB
[ "['Abhinav Thanda' 'Shankar M Venkatesan']", "Abhinav Thanda, Shankar M Venkatesan" ]
cs.CL cs.LG
null
1701.02481
null
null
http://arxiv.org/pdf/1701.02481v3
2017-05-08T03:19:20Z
2017-01-10T08:59:38Z
Implicitly Incorporating Morphological Information into Word Embedding
In this paper, we propose three novel models to enhance word embedding by implicitly using morphological information. Experiments on word similarity and syntactic analogy show that the implicit models are superior to traditional explicit ones. Our models outperform all state-of-the-art baselines and significantly improve the performance on both tasks. Moreover, our performance on the smallest corpus is similar to the performance of CBOW on the corpus which is five times the size of ours. Parameter analysis indicates that the implicit models can supplement semantic information during the word embedding training process.
[ "['Yang Xu' 'Jiawei Liu']", "Yang Xu and Jiawei Liu" ]
cs.LG cs.AI cs.GT
10.1145/3018661.3018702
1701.0249
null
null
null
null
null
Real-Time Bidding by Reinforcement Learning in Display Advertising
The majority of online display ads are served through real-time bidding (RTB) --- each ad display impression is auctioned off in real-time when it is just being generated from a user visit. To place an ad automatically and optimally, it is critical for advertisers to devise a learning algorithm to cleverly bid an ad impression in real-time. Most previous works consider the bid decision as a static optimization problem of either treating the value of each impression independently or setting a bid price to each segment of ad volume. However, the bidding for a given ad campaign would repeatedly happen during its life span before the budget runs out. As such, each bid is strategically correlated by the constrained budget and the overall effectiveness of the campaign (e.g., the rewards from generated clicks), which is only observed after the campaign has completed. Thus, it is of great interest to devise an optimal bidding strategy sequentially so that the campaign budget can be dynamically allocated across all the available impressions on the basis of both the immediate and future rewards. In this paper, we formulate the bid decision process as a reinforcement learning problem, where the state space is represented by the auction information and the campaign's real-time parameters, while an action is the bid price to set. By modeling the state transition via auction competition, we build a Markov Decision Process framework for learning the optimal bidding policy to optimize the advertising performance in the dynamic real-time bidding environment. Furthermore, the scalability problem from the large real-world auction volume and campaign budget is well handled by state value approximation using neural networks.
[ "Han Cai, Kan Ren, Weinan Zhang, Kleanthis Malialis, Jun Wang, Yong Yu,\n Defeng Guo" ]
null
null
1701.02490
null
null
http://arxiv.org/abs/1701.02490v2
2017-01-12T01:37:39Z
2017-01-10T09:30:29Z
Real-Time Bidding by Reinforcement Learning in Display Advertising
The majority of online display ads are served through real-time bidding (RTB) --- each ad display impression is auctioned off in real-time when it is just being generated from a user visit. To place an ad automatically and optimally, it is critical for advertisers to devise a learning algorithm to cleverly bid an ad impression in real-time. Most previous works consider the bid decision as a static optimization problem of either treating the value of each impression independently or setting a bid price to each segment of ad volume. However, the bidding for a given ad campaign would repeatedly happen during its life span before the budget runs out. As such, each bid is strategically correlated by the constrained budget and the overall effectiveness of the campaign (e.g., the rewards from generated clicks), which is only observed after the campaign has completed. Thus, it is of great interest to devise an optimal bidding strategy sequentially so that the campaign budget can be dynamically allocated across all the available impressions on the basis of both the immediate and future rewards. In this paper, we formulate the bid decision process as a reinforcement learning problem, where the state space is represented by the auction information and the campaign's real-time parameters, while an action is the bid price to set. By modeling the state transition via auction competition, we build a Markov Decision Process framework for learning the optimal bidding policy to optimize the advertising performance in the dynamic real-time bidding environment. Furthermore, the scalability problem from the large real-world auction volume and campaign budget is well handled by state value approximation using neural networks.
[ "['Han Cai' 'Kan Ren' 'Weinan Zhang' 'Kleanthis Malialis' 'Jun Wang'\n 'Yong Yu' 'Defeng Guo']" ]
cs.LG stat.ML
10.1109/TNNLS.2020.2973293
1701.02511
null
null
http://arxiv.org/abs/1701.02511v5
2020-02-10T01:31:57Z
2017-01-10T10:42:25Z
Heterogeneous domain adaptation: An unsupervised approach
Domain adaptation leverages the knowledge in one domain - the source domain - to improve learning efficiency in another domain - the target domain. Existing heterogeneous domain adaptation research is relatively well-progressed, but only in situations where the target domain contains at least a few labeled instances. In contrast, heterogeneous domain adaptation with an unlabeled target domain has not been well-studied. To contribute to the research in this emerging field, this paper presents: (1) an unsupervised knowledge transfer theorem that guarantees the correctness of transferring knowledge; and (2) a principal angle-based metric to measure the distance between two pairs of domains: one pair comprises the original source and target domains and the other pair comprises two homogeneous representations of two domains. The theorem and the metric have been implemented in an innovative transfer model, called a Grassmann-Linear monotonic maps-geodesic flow kernel (GLG), that is specifically designed for heterogeneous unsupervised domain adaptation (HeUDA). The linear monotonic maps meet the conditions of the theorem and are used to construct homogeneous representations of the heterogeneous domains. The metric shows the extent to which the homogeneous representations have preserved the information in the original source and target domains. By minimizing the proposed metric, the GLG model learns the homogeneous representations of heterogeneous domains and transfers knowledge through these learned representations via a geodesic flow kernel. To evaluate the model, five public datasets were reorganized into ten HeUDA tasks across three applications: cancer detection, credit assessment, and text classification. The experiments demonstrate that the proposed model delivers superior performance over the existing baselines.
[ "Feng Liu, Guanquan Zhang, Jie Lu", "['Feng Liu' 'Guanquan Zhang' 'Jie Lu']" ]
cs.CV cs.LG
null
1701.02676
null
null
http://arxiv.org/pdf/1701.02676v1
2017-01-10T16:43:03Z
2017-01-10T16:43:03Z
Unsupervised Image-to-Image Translation with Generative Adversarial Networks
It's useful to automatically transform an image from its original form to some synthetic form (style, partial contents, etc.), while keeping the original structure or semantics. We define this requirement as the "image-to-image translation" problem, and propose a general approach to achieve it, based on deep convolutional and conditional generative adversarial networks (GANs), which has gained a phenomenal success to learn mapping images from noise input since 2014. In this work, we develop a two step (unsupervised) learning method to translate images between different domains by using unlabeled images without specifying any correspondence between them, so that to avoid the cost of acquiring labeled data. Compared with prior works, we demonstrated the capacity of generality in our model, by which variance of translations can be conduct by a single type of model. Such capability is desirable in applications like bidirectional translation
[ "Hao Dong, Paarth Neekhara, Chao Wu, Yike Guo", "['Hao Dong' 'Paarth Neekhara' 'Chao Wu' 'Yike Guo']" ]
cs.CL cs.LG stat.ML
null
1701.0272
null
null
null
null
null
Towards End-to-End Speech Recognition with Deep Convolutional Neural Networks
Convolutional Neural Networks (CNNs) are effective models for reducing spectral variations and modeling spectral correlations in acoustic features for automatic speech recognition (ASR). Hybrid speech recognition systems incorporating CNNs with Hidden Markov Models/Gaussian Mixture Models (HMMs/GMMs) have achieved the state-of-the-art in various benchmarks. Meanwhile, Connectionist Temporal Classification (CTC) with Recurrent Neural Networks (RNNs), which is proposed for labeling unsegmented sequences, makes it feasible to train an end-to-end speech recognition system instead of hybrid settings. However, RNNs are computationally expensive and sometimes difficult to train. In this paper, inspired by the advantages of both CNNs and the CTC approach, we propose an end-to-end speech framework for sequence labeling, by combining hierarchical CNNs with CTC directly without recurrent connections. By evaluating the approach on the TIMIT phoneme recognition task, we show that the proposed model is not only computationally efficient, but also competitive with the existing baseline systems. Moreover, we argue that CNNs have the capability to model temporal correlations with appropriate context information.
[ "Ying Zhang, Mohammad Pezeshki, Philemon Brakel, Saizheng Zhang, Cesar\n Laurent Yoshua Bengio, Aaron Courville" ]
null
null
1701.02720
null
null
http://arxiv.org/pdf/1701.02720v1
2017-01-10T18:30:11Z
2017-01-10T18:30:11Z
Towards End-to-End Speech Recognition with Deep Convolutional Neural Networks
Convolutional Neural Networks (CNNs) are effective models for reducing spectral variations and modeling spectral correlations in acoustic features for automatic speech recognition (ASR). Hybrid speech recognition systems incorporating CNNs with Hidden Markov Models/Gaussian Mixture Models (HMMs/GMMs) have achieved the state-of-the-art in various benchmarks. Meanwhile, Connectionist Temporal Classification (CTC) with Recurrent Neural Networks (RNNs), which is proposed for labeling unsegmented sequences, makes it feasible to train an end-to-end speech recognition system instead of hybrid settings. However, RNNs are computationally expensive and sometimes difficult to train. In this paper, inspired by the advantages of both CNNs and the CTC approach, we propose an end-to-end speech framework for sequence labeling, by combining hierarchical CNNs with CTC directly without recurrent connections. By evaluating the approach on the TIMIT phoneme recognition task, we show that the proposed model is not only computationally efficient, but also competitive with the existing baseline systems. Moreover, we argue that CNNs have the capability to model temporal correlations with appropriate context information.
[ "['Ying Zhang' 'Mohammad Pezeshki' 'Philemon Brakel' 'Saizheng Zhang'\n 'Cesar Laurent Yoshua Bengio' 'Aaron Courville']" ]
stat.ML cs.IT cs.LG math.IT
null
1701.02789
null
null
http://arxiv.org/pdf/1701.02789v3
2017-03-09T22:50:38Z
2017-01-10T21:26:03Z
Identifying Best Interventions through Online Importance Sampling
Motivated by applications in computational advertising and systems biology, we consider the problem of identifying the best out of several possible soft interventions at a source node $V$ in an acyclic causal directed graph, to maximize the expected value of a target node $Y$ (located downstream of $V$). Our setting imposes a fixed total budget for sampling under various interventions, along with cost constraints on different types of interventions. We pose this as a best arm identification bandit problem with $K$ arms where each arm is a soft intervention at $V,$ and leverage the information leakage among the arms to provide the first gap dependent error and simple regret bounds for this problem. Our results are a significant improvement over the traditional best arm identification results. We empirically show that our algorithms outperform the state of the art in the Flow Cytometry data-set, and also apply our algorithm for model interpretation of the Inception-v3 deep net that classifies images.
[ "Rajat Sen, Karthikeyan Shanmugam, Alexandros G. Dimakis, and Sanjay\n Shakkottai", "['Rajat Sen' 'Karthikeyan Shanmugam' 'Alexandros G. Dimakis'\n 'Sanjay Shakkottai']" ]
stat.ML cs.LG
10.1109/TSP.2017.2739100
1701.02804
null
null
http://arxiv.org/abs/1701.02804v1
2017-01-07T03:44:54Z
2017-01-07T03:44:54Z
Similarity Function Tracking using Pairwise Comparisons
Recent work in distance metric learning has focused on learning transformations of data that best align with specified pairwise similarity and dissimilarity constraints, often supplied by a human observer. The learned transformations lead to improved retrieval, classification, and clustering algorithms due to the better adapted distance or similarity measures. Here, we address the problem of learning these transformations when the underlying constraint generation process is nonstationary. This nonstationarity can be due to changes in either the ground-truth clustering used to generate constraints or changes in the feature subspaces in which the class structure is apparent. We propose Online Convex Ensemble StrongLy Adaptive Dynamic Learning (OCELAD), a general adaptive, online approach for learning and tracking optimal metrics as they change over time that is highly robust to a variety of nonstationary behaviors in the changing metric. We apply the OCELAD framework to an ensemble of online learners. Specifically, we create a retro-initialized composite objective mirror descent (COMID) ensemble (RICE) consisting of a set of parallel COMID learners with different learning rates, and demonstrate parameter-free RICE-OCELAD metric learning on both synthetic data and a highly nonstationary Twitter dataset. We show significant performance improvements and increased robustness to nonstationary effects relative to previously proposed batch and online distance metric learning algorithms.
[ "['Kristjan Greenewald' 'Stephen Kelley' 'Brandon Oselio'\n 'Alfred O. Hero III']", "Kristjan Greenewald, Stephen Kelley, Brandon Oselio, Alfred O. Hero\n III" ]
cs.LG cs.CV stat.ML
null
1701.02815
null
null
http://arxiv.org/pdf/1701.02815v2
2017-08-12T21:36:09Z
2017-01-11T00:23:34Z
Stochastic Generative Hashing
Learning-based binary hashing has become a powerful paradigm for fast search and retrieval in massive databases. However, due to the requirement of discrete outputs for the hash functions, learning such functions is known to be very challenging. In addition, the objective functions adopted by existing hashing techniques are mostly chosen heuristically. In this paper, we propose a novel generative approach to learn hash functions through Minimum Description Length principle such that the learned hash codes maximally compress the dataset and can also be used to regenerate the inputs. We also develop an efficient learning algorithm based on the stochastic distributional gradient, which avoids the notorious difficulty caused by binary output constraints, to jointly optimize the parameters of the hash function and the associated generative model. Extensive experiments on a variety of large-scale datasets show that the proposed method achieves better retrieval results than the existing state-of-the-art methods.
[ "Bo Dai, Ruiqi Guo, Sanjiv Kumar, Niao He, Le Song", "['Bo Dai' 'Ruiqi Guo' 'Sanjiv Kumar' 'Niao He' 'Le Song']" ]
cs.LG
null
1701.02886
null
null
http://arxiv.org/pdf/1701.02886v4
2019-02-07T08:26:12Z
2017-01-11T08:36:54Z
The empirical Christoffel function with applications in data analysis
We illustrate the potential applications in machine learning of the Christoffel function, or more precisely, its empirical counterpart associated with a counting measure uniformly supported on a finite set of points. Firstly, we provide a thresholding scheme which allows to approximate the support of a measure from a finite subset of its moments with strong asymptotic guaranties. Secondly, we provide a consistency result which relates the empirical Christoffel function and its population counterpart in the limit of large samples. Finally, we illustrate the relevance of our results on simulated and real world datasets for several applications in statistics and machine learning: (a) density and support estimation from finite samples, (b) outlier and novelty detection and (c) affine matching.
[ "Jean-Bernard Lasserre and Edouard Pauwels", "['Jean-Bernard Lasserre' 'Edouard Pauwels']" ]
stat.ML cs.CV cs.LG
null
1701.02892
null
null
http://arxiv.org/pdf/1701.02892v1
2017-01-11T08:52:53Z
2017-01-11T08:52:53Z
Multivariate Regression with Grossly Corrupted Observations: A Robust Approach and its Applications
This paper studies the problem of multivariate linear regression where a portion of the observations is grossly corrupted or is missing, and the magnitudes and locations of such occurrences are unknown in priori. To deal with this problem, we propose a new approach by explicitly consider the error source as well as its sparseness nature. An interesting property of our approach lies in its ability of allowing individual regression output elements or tasks to possess their unique noise levels. Moreover, despite working with a non-smooth optimization problem, our approach still guarantees to converge to its optimal solution. Experiments on synthetic data demonstrate the competitiveness of our approach compared with existing multivariate regression models. In addition, empirically our approach has been validated with very promising results on two exemplar real-world applications: The first concerns the prediction of \textit{Big-Five} personality based on user behaviors at social network sites (SNSs), while the second is 3D human hand pose estimation from depth images. The implementation of our approach and comparison methods as well as the involved datasets are made publicly available in support of the open-source and reproducible research initiatives.
[ "['Xiaowei Zhang' 'Chi Xu' 'Yu Zhang' 'Tingshao Zhu' 'Li Cheng']", "Xiaowei Zhang and Chi Xu and Yu Zhang and Tingshao Zhu and Li Cheng" ]
cs.LG stat.ML
null
1701.0296
null
null
null
null
null
Fast mixing for Latent Dirichlet allocation
Markov chain Monte Carlo (MCMC) algorithms are ubiquitous in probability theory in general and in machine learning in particular. A Markov chain is devised so that its stationary distribution is some probability distribution of interest. Then one samples from the given distribution by running the Markov chain for a "long time" until it appears to be stationary and then collects the sample. However these chains are often very complex and there are no theoretical guarantees that stationarity is actually reached. In this paper we study the Gibbs sampler of the posterior distribution of a very simple case of Latent Dirichlet Allocation, the arguably most well known Bayesian unsupervised learning model for text generation and text classification. It is shown that when the corpus consists of two long documents of equal length $m$ and the vocabulary consists of only two different words, the mixing time is at most of order $m^2\log m$ (which corresponds to $m\log m$ rounds over the corpus). It will be apparent from our analysis that it seems very likely that the mixing time is not much worse in the more relevant case when the number of documents and the size of the vocabulary are also large as long as each word is represented a large number in each document, even though the computations involved may be intractable.
[ "Johan Jonasson" ]
null
null
1701.02960
null
null
http://arxiv.org/pdf/1701.02960v2
2017-11-01T14:01:34Z
2017-01-11T13:08:52Z
Fast mixing for Latent Dirichlet allocation
Markov chain Monte Carlo (MCMC) algorithms are ubiquitous in probability theory in general and in machine learning in particular. A Markov chain is devised so that its stationary distribution is some probability distribution of interest. Then one samples from the given distribution by running the Markov chain for a "long time" until it appears to be stationary and then collects the sample. However these chains are often very complex and there are no theoretical guarantees that stationarity is actually reached. In this paper we study the Gibbs sampler of the posterior distribution of a very simple case of Latent Dirichlet Allocation, the arguably most well known Bayesian unsupervised learning model for text generation and text classification. It is shown that when the corpus consists of two long documents of equal length $m$ and the vocabulary consists of only two different words, the mixing time is at most of order $m^2log m$ (which corresponds to $mlog m$ rounds over the corpus). It will be apparent from our analysis that it seems very likely that the mixing time is not much worse in the more relevant case when the number of documents and the size of the vocabulary are also large as long as each word is represented a large number in each document, even though the computations involved may be intractable.
[ "['Johan Jonasson']" ]
stat.ML cs.LG
null
1701.03006
null
null
http://arxiv.org/pdf/1701.03006v1
2017-01-11T15:18:18Z
2017-01-11T15:18:18Z
Compressive Sensing via Convolutional Factor Analysis
We solve the compressive sensing problem via convolutional factor analysis, where the convolutional dictionaries are learned {\em in situ} from the compressed measurements. An alternating direction method of multipliers (ADMM) paradigm for compressive sensing inversion based on convolutional factor analysis is developed. The proposed algorithm provides reconstructed images as well as features, which can be directly used for recognition ($e.g.$, classification) tasks. When a deep (multilayer) model is constructed, a stochastic unpooling process is employed to build a generative model. During reconstruction and testing, we project the upper layer dictionary to the data level and only a single layer deconvolution is required. We demonstrate that using $\sim30\%$ (relative to pixel numbers) compressed measurements, the proposed model achieves the classification accuracy comparable to the original data on MNIST. We also observe that when the compressed measurements are very limited ($e.g.$, $<10\%$), the upper layer dictionary can provide better reconstruction results than the bottom layer.
[ "['Xin Yuan' 'Yunchen Pu' 'Lawrence Carin']", "Xin Yuan, Yunchen Pu, Lawrence Carin" ]
cs.CV cs.LG stat.ML
null
1701.03077
null
null
null
null
null
A General and Adaptive Robust Loss Function
We present a generalization of the Cauchy/Lorentzian, Geman-McClure, Welsch/Leclerc, generalized Charbonnier, Charbonnier/pseudo-Huber/L1-L2, and L2 loss functions. By introducing robustness as a continuous parameter, our loss function allows algorithms built around robust loss minimization to be generalized, which improves performance on basic vision tasks such as registration and clustering. Interpreting our loss as the negative log of a univariate density yields a general probability distribution that includes normal and Cauchy distributions as special cases. This probabilistic interpretation enables the training of neural networks in which the robustness of the loss automatically adapts itself during training, which improves performance on learning-based tasks such as generative image synthesis and unsupervised monocular depth estimation, without requiring any manual parameter tuning.
[ "Jonathan T. Barron" ]
null
null
1701.03077v
null
null
http://arxiv.org/pdf/1701.03077v10
2019-04-04T20:05:33Z
2017-01-11T17:39:14Z
A General and Adaptive Robust Loss Function
We present a generalization of the Cauchy/Lorentzian, Geman-McClure, Welsch/Leclerc, generalized Charbonnier, Charbonnier/pseudo-Huber/L1-L2, and L2 loss functions. By introducing robustness as a continuous parameter, our loss function allows algorithms built around robust loss minimization to be generalized, which improves performance on basic vision tasks such as registration and clustering. Interpreting our loss as the negative log of a univariate density yields a general probability distribution that includes normal and Cauchy distributions as special cases. This probabilistic interpretation enables the training of neural networks in which the robustness of the loss automatically adapts itself during training, which improves performance on learning-based tasks such as generative image synthesis and unsupervised monocular depth estimation, without requiring any manual parameter tuning.
[ "['Jonathan T. Barron']" ]
cs.CV cs.AI cs.LG stat.ML
null
1701.03102
null
null
http://arxiv.org/pdf/1701.03102v1
2017-01-11T16:34:29Z
2017-01-11T16:34:29Z
Linear Disentangled Representation Learning for Facial Actions
Limited annotated data available for the recognition of facial expression and action units embarrasses the training of deep networks, which can learn disentangled invariant features. However, a linear model with just several parameters normally is not demanding in terms of training data. In this paper, we propose an elegant linear model to untangle confounding factors in challenging realistic multichannel signals such as 2D face videos. The simple yet powerful model does not rely on huge training data and is natural for recognizing facial actions without explicitly disentangling the identity. Base on well-understood intuitive linear models such as Sparse Representation based Classification (SRC), previous attempts require a prepossessing of explicit decoupling which is practically inexact. Instead, we exploit the low-rank property across frames to subtract the underlying neutral faces which are modeled jointly with sparse representation on the action components with group sparsity enforced. On the extended Cohn-Kanade dataset (CK+), our one-shot automatic method on raw face videos performs as competitive as SRC applied on manually prepared action components and performs even better than SRC in terms of true positive rate. We apply the model to the even more challenging task of facial action unit recognition, verified on the MPI Face Video Database (MPI-VDB) achieving a decent performance. All the programs and data have been made publicly available.
[ "['Xiang Xiang' 'Trac D. Tran']", "Xiang Xiang, Trac D. Tran" ]
stat.AP cs.AI cs.LG
null
1701.03162
null
null
http://arxiv.org/pdf/1701.03162v1
2016-12-10T06:30:25Z
2016-12-10T06:30:25Z
Real-time eSports Match Result Prediction
In this paper, we try to predict the winning team of a match in the multiplayer eSports game Dota 2. To address the weaknesses of previous work, we consider more aspects of prior (pre-match) features from individual players' match history, as well as real-time (during-match) features at each minute as the match progresses. We use logistic regression, the proposed Attribute Sequence Model, and their combinations as the prediction models. In a dataset of 78362 matches where 20631 matches contain replay data, our experiments show that adding more aspects of prior features improves accuracy from 58.69% to 71.49%, and introducing real-time features achieves up to 93.73% accuracy when predicting at the 40th minute.
[ "Yifan Yang and Tian Qin and Yu-Heng Lei", "['Yifan Yang' 'Tian Qin' 'Yu-Heng Lei']" ]
cs.LG cs.SD
null
1701.03198
null
null
http://arxiv.org/pdf/1701.03198v1
2017-01-12T01:02:22Z
2017-01-12T01:02:22Z
Unsupervised Latent Behavior Manifold Learning from Acoustic Features: audio2behavior
Behavioral annotation using signal processing and machine learning is highly dependent on training data and manual annotations of behavioral labels. Previous studies have shown that speech information encodes significant behavioral information and be used in a variety of automated behavior recognition tasks. However, extracting behavior information from speech is still a difficult task due to the sparseness of training data coupled with the complex, high-dimensionality of speech, and the complex and multiple information streams it encodes. In this work we exploit the slow varying properties of human behavior. We hypothesize that nearby segments of speech share the same behavioral context and hence share a similar underlying representation in a latent space. Specifically, we propose a Deep Neural Network (DNN) model to connect behavioral context and derive the behavioral manifold in an unsupervised manner. We evaluate the proposed manifold in the couples therapy domain and also provide examples from publicly available data (e.g. stand-up comedy). We further investigate training within the couples' therapy domain and from movie data. The results are extremely encouraging and promise improved behavioral quantification in an unsupervised manner and warrants further investigation in a range of applications.
[ "['Haoqi Li' 'Brian Baucom' 'Panayiotis Georgiou']", "Haoqi Li, Brian Baucom, Panayiotis Georgiou" ]