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22,202
Gradient Importance Sampling
stat.ML
Adaptive Monte Carlo schemes developed over the last years usually seek to ensure ergodicity of the sampling process in line with MCMC tradition. This poses constraints on what is possible in terms of adaptation. In the general case ergodicity can only be guaranteed if adaptation is diminished at a certain rate. Import...
computer science
22,203
A statistical perspective of sampling scores for linear regression
stat.ML
In this paper, we consider a statistical problem of learning a linear model from noisy samples. Existing work has focused on approximating the least squares solution by using leverage-based scores as an importance sampling distribution. However, no finite sample statistical guarantees and no computationally efficient o...
computer science
22,204
Sparsity in Multivariate Extremes with Applications to Anomaly Detection
stat.ML
Capturing the dependence structure of multivariate extreme events is a major concern in many fields involving the management of risks stemming from multiple sources, e.g. portfolio monitoring, insurance, environmental risk management and anomaly detection. One convenient (non-parametric) characterization of extremal de...
computer science
22,205
Admissibility of a posterior predictive decision rule
stat.ML
Recent decades have seen an interest in prediction problems for which Bayesian methodology has been used ubiquitously. Sampling from or approximating the posterior predictive distribution in a Bayesian model allows one to make inferential statements about potentially observable random quantities given observed data. Th...
computer science
22,206
Optimal Learning Rates for Localized SVMs
stat.ML
One of the limiting factors of using support vector machines (SVMs) in large scale applications are their super-linear computational requirements in terms of the number of training samples. To address this issue, several approaches that train SVMs on many small chunks of large data sets separately have been proposed in...
computer science
22,207
Clustering of Modal Valued Symbolic Data
stat.ML
Symbolic Data Analysis is based on special descriptions of data - symbolic objects (SO). Such descriptions preserve more detailed information about units and their clusters than the usual representations with mean values. A special kind of symbolic object is a representation with frequency or probability distributions ...
computer science
22,208
String and Membrane Gaussian Processes
stat.ML
In this paper we introduce a novel framework for making exact nonparametric Bayesian inference on latent functions, that is particularly suitable for Big Data tasks. Firstly, we introduce a class of stochastic processes we refer to as string Gaussian processes (string GPs), which are not to be mistaken for Gaussian pro...
computer science
22,209
Context-aware learning for finite mixture models
stat.ML
This work introduces algorithms able to exploit contextual information in order to improve maximum-likelihood (ML) parameter estimation in finite mixture models (FMM), demonstrating their benefits and properties in several scenarios. The proposed algorithms are derived in a probabilistic framework with regard to situat...
computer science
22,210
Regularized Multi-Task Learning for Multi-Dimensional Log-Density Gradient Estimation
stat.ML
Log-density gradient estimation is a fundamental statistical problem and possesses various practical applications such as clustering and measuring non-Gaussianity. A naive two-step approach of first estimating the density and then taking its log-gradient is unreliable because an accurate density estimate does not neces...
computer science
22,211
Direct Estimation of the Derivative of Quadratic Mutual Information with Application in Supervised Dimension Reduction
stat.ML
A typical goal of supervised dimension reduction is to find a low-dimensional subspace of the input space such that the projected input variables preserve maximal information about the output variables. The dependence maximization approach solves the supervised dimension reduction problem through maximizing a statistic...
computer science
22,212
Non-isometric Curve to Surface Matching with Incomplete Data for Functional Calibration
stat.ML
Calibration refers to the process of adjusting features of a computational model that are not observed in the physical process so that the model matches the real process. We propose a framework for calibration when the unobserved features, i.e. calibration parameters, do not assume a single value, but are functionally ...
computer science
22,213
Sparse Pseudo-input Local Kriging for Large Non-stationary Spatial Datasets with Exogenous Variables
stat.ML
Gaussian process (GP) regression is a powerful tool for building predictive models for spatial systems. However, it does not scale efficiently for large datasets. Particularly, for high-dimensional spatial datasets, i.e., spatial datasets that contain exogenous variables, the performance of GP regression further deteri...
computer science
22,214
Distributional Equivalence and Structure Learning for Bow-free Acyclic Path Diagrams
stat.ML
We consider the problem of structure learning for bow-free acyclic path diagrams (BAPs). BAPs can be viewed as a generalization of linear Gaussian DAG models that allow for certain hidden variables. We present a first method for this problem using a greedy score-based search algorithm. We also prove some necessary and ...
computer science
22,215
Convergence rates of sub-sampled Newton methods
stat.ML
We consider the problem of minimizing a sum of $n$ functions over a convex parameter set $\mathcal{C} \subset \mathbb{R}^p$ where $n\gg p\gg 1$. In this regime, algorithms which utilize sub-sampling techniques are known to be effective. In this paper, we use sub-sampling techniques together with low-rank approximation ...
computer science
22,216
Bayesian Dropout
stat.ML
Dropout has recently emerged as a powerful and simple method for training neural networks preventing co-adaptation by stochastically omitting neurons. Dropout is currently not grounded in explicit modelling assumptions which so far has precluded its adoption in Bayesian modelling. Using Bayesian entropic reasoning we s...
computer science
22,217
Neyman-Pearson Classification under High-Dimensional Settings
stat.ML
Most existing binary classification methods target on the optimization of the overall classification risk and may fail to serve some real-world applications such as cancer diagnosis, where users are more concerned with the risk of misclassifying one specific class than the other. Neyman-Pearson (NP) paradigm was introd...
computer science
22,218
Unbounded Bayesian Optimization via Regularization
stat.ML
Bayesian optimization has recently emerged as a popular and efficient tool for global optimization and hyperparameter tuning. Currently, the established Bayesian optimization practice requires a user-defined bounding box which is assumed to contain the optimizer. However, when little is known about the probed objective...
computer science
22,219
Non-Stationary Gaussian Process Regression with Hamiltonian Monte Carlo
stat.ML
We present a novel approach for fully non-stationary Gaussian process regression (GPR), where all three key parameters -- noise variance, signal variance and lengthscale -- can be simultaneously input-dependent. We develop gradient-based inference methods to learn the unknown function and the non-stationary model param...
computer science
22,220
Spatio-temporal Spike and Slab Priors for Multiple Measurement Vector Problems
stat.ML
We are interested in solving the multiple measurement vector (MMV) problem for instances, where the underlying sparsity pattern exhibit spatio-temporal structure motivated by the electroencephalogram (EEG) source localization problem. We propose a probabilistic model that takes this structure into account by generalizi...
computer science
22,221
Another Look at DWD: Thrifty Algorithm and Bayes Risk Consistency in RKHS
stat.ML
Distance weighted discrimination (DWD) is a margin-based classifier with an interesting geometric motivation. DWD was originally proposed as a superior alternative to the support vector machine (SVM), however DWD is yet to be popular compared with the SVM. The main reasons are twofold. First, the state-of-the-art algor...
computer science
22,222
Calibration of One-Class SVM for MV set estimation
stat.ML
A general approach for anomaly detection or novelty detection consists in estimating high density regions or Minimum Volume (MV) sets. The One-Class Support Vector Machine (OCSVM) is a state-of-the-art algorithm for estimating such regions from high dimensional data. Yet it suffers from practical limitations. When appl...
computer science
22,223
Stochastic gradient variational Bayes for gamma approximating distributions
stat.ML
While stochastic variational inference is relatively well known for scaling inference in Bayesian probabilistic models, related methods also offer ways to circumnavigate the approximation of analytically intractable expectations. The key challenge in either setting is controlling the variance of gradient estimates: rec...
computer science
22,224
Matrix Factorisation with Linear Filters
stat.ML
This text investigates relations between two well-known family of algorithms, matrix factorisations and recursive linear filters, by describing a probabilistic model in which approximate inference corresponds to a matrix factorisation algorithm. Using the probabilistic model, we derive a matrix factorisation algorithm ...
computer science
22,225
Poisson Subsampling Algorithms for Large Sample Linear Regression in Massive Data
stat.ML
Large sample size brings the computation bottleneck for modern data analysis. Subsampling is one of efficient strategies to handle this problem. In previous studies, researchers make more fo- cus on subsampling with replacement (SSR) than on subsampling without replacement (SSWR). In this paper we investigate a kind of...
computer science
22,226
Modelling time evolving interactions in networks through a non stationary extension of stochastic block models
stat.ML
In this paper, we focus on the stochastic block model (SBM),a probabilistic tool describing interactions between nodes of a network using latent clusters. The SBM assumes that the networkhas a stationary structure, in which connections of time varying intensity are not taken into account. In other words, interactions b...
computer science
22,227
Empirical risk minimization is consistent with the mean absolute percentage error
stat.ML
We study in this paper the consequences of using the Mean Absolute Percentage Error (MAPE) as a measure of quality for regression models. We show that finding the best model under the MAPE is equivalent to doing weighted Mean Absolute Error (MAE) regression. We also show that, under some asumptions, universal consisten...
computer science
22,228
A Variational Bayesian State-Space Approach to Online Passive-Aggressive Regression
stat.ML
Online Passive-Aggressive (PA) learning is a class of online margin-based algorithms suitable for a wide range of real-time prediction tasks, including classification and regression. PA algorithms are formulated in terms of deterministic point-estimation problems governed by a set of user-defined hyperparameters: the a...
computer science
22,229
Fast Second-Order Stochastic Backpropagation for Variational Inference
stat.ML
We propose a second-order (Hessian or Hessian-free) based optimization method for variational inference inspired by Gaussian backpropagation, and argue that quasi-Newton optimization can be developed as well. This is accomplished by generalizing the gradient computation in stochastic backpropagation via a reparametriza...
computer science
22,230
Sélection de variables par le GLM-Lasso pour la prédiction du risque palustre
stat.ML
In this study, we propose an automatic learning method for variables selection based on Lasso in epidemiology context. One of the aim of this approach is to overcome the pretreatment of experts in medicine and epidemiology on collected data. These pretreatment consist in recoding some variables and to choose some inter...
computer science
22,231
Learning the Number of Autoregressive Mixtures in Time Series Using the Gap Statistics
stat.ML
Using a proper model to characterize a time series is crucial in making accurate predictions. In this work we use time-varying autoregressive process (TVAR) to describe non-stationary time series and model it as a mixture of multiple stable autoregressive (AR) processes. We introduce a new model selection technique bas...
computer science
22,232
When are Kalman-filter restless bandits indexable?
stat.ML
We study the restless bandit associated with an extremely simple scalar Kalman filter model in discrete time. Under certain assumptions, we prove that the problem is indexable in the sense that the Whittle index is a non-decreasing function of the relevant belief state. In spite of the long history of this problem, thi...
computer science
22,233
Macau: Scalable Bayesian Multi-relational Factorization with Side Information using MCMC
stat.ML
We propose Macau, a powerful and flexible Bayesian factorization method for heterogeneous data. Our model can factorize any set of entities and relations that can be represented by a relational model, including tensors and also multiple relations for each entity. Macau can also incorporate side information, specificall...
computer science
22,234
Large-Scale Optimization Algorithms for Sparse Conditional Gaussian Graphical Models
stat.ML
This paper addresses the problem of scalable optimization for L1-regularized conditional Gaussian graphical models. Conditional Gaussian graphical models generalize the well-known Gaussian graphical models to conditional distributions to model the output network influenced by conditioning input variables. While highly ...
computer science
22,235
Dirichlet Fragmentation Processes
stat.ML
Tree structures are ubiquitous in data across many domains, and many datasets are naturally modelled by unobserved tree structures. In this paper, first we review the theory of random fragmentation processes [Bertoin, 2006], and a number of existing methods for modelling trees, including the popular nested Chinese rest...
computer science
22,236
A Statistical Theory of Deep Learning via Proximal Splitting
stat.ML
In this paper we develop a statistical theory and an implementation of deep learning models. We show that an elegant variable splitting scheme for the alternating direction method of multipliers optimises a deep learning objective. We allow for non-smooth non-convex regularisation penalties to induce sparsity in parame...
computer science
22,237
Density Estimation via Discrepancy
stat.ML
Given i.i.d samples from some unknown continuous density on hyper-rectangle $[0, 1]^d$, we attempt to learn a piecewise constant function that approximates this underlying density non-parametrically. Our density estimate is defined on a binary split of $[0, 1]^d$ and built up sequentially according to discrepancy crite...
computer science
22,238
High Dimensional Data Modeling Techniques for Detection of Chemical Plumes and Anomalies in Hyperspectral Images and Movies
stat.ML
We briefly review recent progress in techniques for modeling and analyzing hyperspectral images and movies, in particular for detecting plumes of both known and unknown chemicals. For detecting chemicals of known spectrum, we extend the technique of using a single subspace for modeling the background to a "mixture of s...
computer science
22,239
Unbiased Bayesian Inference for Population Markov Jump Processes via Random Truncations
stat.ML
We consider continuous time Markovian processes where populations of individual agents interact stochastically according to kinetic rules. Despite the increasing prominence of such models in fields ranging from biology to smart cities, Bayesian inference for such systems remains challenging, as these are continuous tim...
computer science
22,240
Tractable Fully Bayesian Inference via Convex Optimization and Optimal Transport Theory
stat.ML
We consider the problem of transforming samples from one continuous source distribution into samples from another target distribution. We demonstrate with optimal transport theory that when the source distribution can be easily sampled from and the target distribution is log-concave, this can be tractably solved with c...
computer science
22,241
Estimating network edge probabilities by neighborhood smoothing
stat.ML
The estimation of probabilities of network edges from the observed adjacency matrix has important applications to predicting missing links and network denoising. It has usually been addressed by estimating the graphon, a function that determines the matrix of edge probabilities, but this is ill-defined without strong a...
computer science
22,242
Maximum Likelihood Latent Space Embedding of Logistic Random Dot Product Graphs
stat.ML
A latent space model for a family of random graphs assigns real-valued vectors to nodes of the graph such that edge probabilities are determined by latent positions. Latent space models provide a natural statistical framework for graph visualizing and clustering. A latent space model of particular interest is the Rando...
computer science
22,243
Bayesian Estimation of Multidimensional Latent Variables and Its Asymptotic Accuracy
stat.ML
Hierarchical learning models, such as mixture models and Bayesian networks, are widely employed for unsupervised learning tasks, such as clustering analysis. They consist of observable and hidden variables, which represent the given data and their hidden generation process, respectively. It has been pointed out that co...
computer science
22,244
Asymptotically Optimal Sequential Experimentation Under Generalized Ranking
stat.ML
We consider the \mnk{classical} problem of a controller activating (or sampling) sequentially from a finite number of $N \geq 2$ populations, specified by unknown distributions. Over some time horizon, at each time $n = 1, 2, \ldots$, the controller wishes to select a population to sample, with the goal of sampling fro...
computer science
22,245
The Knowledge Gradient with Logistic Belief Models for Binary Classification
stat.ML
We consider sequential decision making problems for binary classification scenario in which the learner takes an active role in repeatedly selecting samples from the action pool and receives the binary label of the selected alternatives. Our problem is motivated by applications where observations are time consuming and...
computer science
22,246
p-Markov Gaussian Processes for Scalable and Expressive Online Bayesian Nonparametric Time Series Forecasting
stat.ML
In this paper we introduce a novel online time series forecasting model we refer to as the pM-GP filter. We show that our model is equivalent to Gaussian process regression, with the advantage that both online forecasting and online learning of the hyper-parameters have a constant (rather than cubic) time complexity an...
computer science
22,247
Consistent Estimation of Low-Dimensional Latent Structure in High-Dimensional Data
stat.ML
We consider the problem of extracting a low-dimensional, linear latent variable structure from high-dimensional random variables. Specifically, we show that under mild conditions and when this structure manifests itself as a linear space that spans the conditional means, it is possible to consistently recover the struc...
computer science
22,248
Robust Learning for Optimal Treatment Decision with NP-Dimensionality
stat.ML
In order to identify important variables that are involved in making optimal treatment decision, Lu et al. (2013) proposed a penalized least squared regression framework for a fixed number of predictors, which is robust against the misspecification of the conditional mean model. Two problems arise: (i) in a world of ex...
computer science
22,249
Change Detection in Multivariate Datastreams: Likelihood and Detectability Loss
stat.ML
We address the problem of detecting changes in multivariate datastreams, and we investigate the intrinsic difficulty that change-detection methods have to face when the data dimension scales. In particular, we consider a general approach where changes are detected by comparing the distribution of the log-likelihood of ...
computer science
22,250
A General Method for Robust Bayesian Modeling
stat.ML
Robust Bayesian models are appealing alternatives to standard models, providing protection from data that contains outliers or other departures from the model assumptions. Historically, robust models were mostly developed on a case-by-case basis; examples include robust linear regression, robust mixture models, and bur...
computer science
22,251
Scalable inference for a full multivariate stochastic volatility model
stat.ML
We introduce a multivariate stochastic volatility model for asset returns that imposes no restrictions to the structure of the volatility matrix and treats all its elements as functions of latent stochastic processes. When the number of assets is prohibitively large, we propose a factor multivariate stochastic volatili...
computer science
22,252
Modularity Component Analysis versus Principal Component Analysis
stat.ML
In this paper the exact linear relation between the leading eigenvectors of the modularity matrix and the singular vectors of an uncentered data matrix is developed. Based on this analysis the concept of a modularity component is defined, and its properties are developed. It is shown that modularity component analysis ...
computer science
22,253
Optimization for Gaussian Processes via Chaining
stat.ML
In this paper, we consider the problem of stochastic optimization under a bandit feedback model. We generalize the GP-UCB algorithm [Srinivas and al., 2012] to arbitrary kernels and search spaces. To do so, we use a notion of localized chaining to control the supremum of a Gaussian process, and provide a novel optimiza...
computer science
22,254
NYTRO: When Subsampling Meets Early Stopping
stat.ML
Early stopping is a well known approach to reduce the time complexity for performing training and model selection of large scale learning machines. On the other hand, memory/space (rather than time) complexity is the main constraint in many applications, and randomized subsampling techniques have been proposed to tackl...
computer science
22,255
Multiple co-clustering based on nonparametric mixture models with heterogeneous marginal distributions
stat.ML
We propose a novel method for multiple clustering that assumes a co-clustering structure (partitions in both rows and columns of the data matrix) in each view. The new method is applicable to high-dimensional data. It is based on a nonparametric Bayesian approach in which the number of views and the number of feature-/...
computer science
22,256
GLASSES: Relieving The Myopia Of Bayesian Optimisation
stat.ML
We present GLASSES: Global optimisation with Look-Ahead through Stochastic Simulation and Expected-loss Search. The majority of global optimisation approaches in use are myopic, in only considering the impact of the next function value; the non-myopic approaches that do exist are able to consider only a handful of futu...
computer science
22,257
Inventory Control Involving Unknown Demand of Discrete Nonperishable Items - Analysis of a Newsvendor-based Policy
stat.ML
Inventory control with unknown demand distribution is considered, with emphasis placed on the case involving discrete nonperishable items. We focus on an adaptive policy which in every period uses, as much as possible, the optimal newsvendor ordering quantity for the empirical distribution learned up to that period. Th...
computer science
22,258
Cascaded High Dimensional Histograms: A Generative Approach to Density Estimation
stat.ML
We present tree- and list- structured density estimation methods for high dimensional binary/categorical data. Our density estimation models are high dimensional analogies to variable bin width histograms. In each leaf of the tree (or list), the density is constant, similar to the flat density within the bin of a histo...
computer science
22,259
A Framework to Adjust Dependency Measure Estimates for Chance
stat.ML
Estimating the strength of dependency between two variables is fundamental for exploratory analysis and many other applications in data mining. For example: non-linear dependencies between two continuous variables can be explored with the Maximal Information Coefficient (MIC); and categorical variables that are depende...
computer science
22,260
Blitzkriging: Kronecker-structured Stochastic Gaussian Processes
stat.ML
We present Blitzkriging, a new approach to fast inference for Gaussian processes, applicable to regression, optimisation and classification. State-of-the-art (stochastic) inference for Gaussian processes on very large datasets scales cubically in the number of 'inducing inputs', variables introduced to factorise the mo...
computer science
22,261
Spectral Convergence Rate of Graph Laplacian
stat.ML
Laplacian Eigenvectors of the graph constructed from a data set are used in many spectral manifold learning algorithms such as diffusion maps and spectral clustering. Given a graph constructed from a random sample of a $d$-dimensional compact submanifold $M$ in $\mathbb{R}^D$, we establish the spectral convergence rate...
computer science
22,262
Fast Landmark Subspace Clustering
stat.ML
Kernel methods obtain superb performance in terms of accuracy for various machine learning tasks since they can effectively extract nonlinear relations. However, their time complexity can be rather large especially for clustering tasks. In this paper we define a general class of kernels that can be easily approximated ...
computer science
22,263
Robust Gaussian Graphical Modeling with the Trimmed Graphical Lasso
stat.ML
Gaussian Graphical Models (GGMs) are popular tools for studying network structures. However, many modern applications such as gene network discovery and social interactions analysis often involve high-dimensional noisy data with outliers or heavier tails than the Gaussian distribution. In this paper, we propose the Tri...
computer science
22,264
Nonconvex Penalization in Sparse Estimation: An Approach Based on the Bernstein Function
stat.ML
In this paper we study nonconvex penalization using Bernstein functions whose first-order derivatives are completely monotone. The Bernstein function can induce a class of nonconvex penalty functions for high-dimensional sparse estimation problems. We derive a thresholding function based on the Bernstein penalty and di...
computer science
22,265
PCA-Based Out-of-Sample Extension for Dimensionality Reduction
stat.ML
Dimensionality reduction methods are very common in the field of high dimensional data analysis. Typically, algorithms for dimensionality reduction are computationally expensive. Therefore, their applications for the analysis of massive amounts of data are impractical. For example, repeated computations due to accumula...
computer science
22,266
Lasso based feature selection for malaria risk exposure prediction
stat.ML
In life sciences, the experts generally use empirical knowledge to recode variables, choose interactions and perform selection by classical approach. The aim of this work is to perform automatic learning algorithm for variables selection which can lead to know if experts can be help in they decision or simply replaced ...
computer science
22,267
Neutralized Empirical Risk Minimization with Generalization Neutrality Bound
stat.ML
Currently, machine learning plays an important role in the lives and individual activities of numerous people. Accordingly, it has become necessary to design machine learning algorithms to ensure that discrimination, biased views, or unfair treatment do not result from decision making or predictions made via machine le...
computer science
22,268
Streaming regularization parameter selection via stochastic gradient descent
stat.ML
We propose a framework to perform streaming covariance selection. Our approach employs regularization constraints where a time-varying sparsity parameter is iteratively estimated via stochastic gradient descent. This allows for the regularization parameter to be efficiently learnt in an online manner. The proposed fram...
computer science
22,269
Learning Instrumental Variables with Non-Gaussianity Assumptions: Theoretical Limitations and Practical Algorithms
stat.ML
Learning a causal effect from observational data is not straightforward, as this is not possible without further assumptions. If hidden common causes between treatment $X$ and outcome $Y$ cannot be blocked by other measurements, one possibility is to use an instrumental variable. In principle, it is possible under some...
computer science
22,270
Black-box $α$-divergence Minimization
stat.ML
Black-box alpha (BB-$\alpha$) is a new approximate inference method based on the minimization of $\alpha$-divergences. BB-$\alpha$ scales to large datasets because it can be implemented using stochastic gradient descent. BB-$\alpha$ can be applied to complex probabilistic models with little effort since it only require...
computer science
22,271
Stochastic Expectation Propagation for Large Scale Gaussian Process Classification
stat.ML
A method for large scale Gaussian process classification has been recently proposed based on expectation propagation (EP). Such a method allows Gaussian process classifiers to be trained on very large datasets that were out of the reach of previous deployments of EP and has been shown to be competitive with related tec...
computer science
22,272
Training Deep Gaussian Processes using Stochastic Expectation Propagation and Probabilistic Backpropagation
stat.ML
Deep Gaussian processes (DGPs) are multi-layer hierarchical generalisations of Gaussian processes (GPs) and are formally equivalent to neural networks with multiple, infinitely wide hidden layers. DGPs are probabilistic and non-parametric and as such are arguably more flexible, have a greater capacity to generalise, an...
computer science
22,273
Automatic Inference of the Quantile Parameter
stat.ML
Supervised learning is an active research area, with numerous applications in diverse fields such as data analytics, computer vision, speech and audio processing, and image understanding. In most cases, the loss functions used in machine learning assume symmetric noise models, and seek to estimate the unknown function ...
computer science
22,274
$k$-means: Fighting against Degeneracy in Sequential Monte Carlo with an Application to Tracking
stat.ML
For regular particle filter algorithm or Sequential Monte Carlo (SMC) methods, the initial weights are traditionally dependent on the proposed distribution, the posterior distribution at the current timestamp in the sampled sequence, and the target is the posterior distribution of the previous timestamp. This is techni...
computer science
22,275
Lass-0: sparse non-convex regression by local search
stat.ML
We compute approximate solutions to L0 regularized linear regression using L1 regularization, also known as the Lasso, as an initialization step. Our algorithm, the Lass-0 ("Lass-zero"), uses a computationally efficient stepwise search to determine a locally optimal L0 solution given any L1 regularization solution. We ...
computer science
22,276
Scalable Gaussian Processes for Characterizing Multidimensional Change Surfaces
stat.ML
We present a scalable Gaussian process model for identifying and characterizing smooth multidimensional changepoints, and automatically learning changes in expressive covariance structure. We use Random Kitchen Sink features to flexibly define a change surface in combination with expressive spectral mixture kernels to ...
computer science
22,277
Probabilistic Segmentation via Total Variation Regularization
stat.ML
We present a convex approach to probabilistic segmentation and modeling of time series data. Our approach builds upon recent advances in multivariate total variation regularization, and seeks to learn a separate set of parameters for the distribution over the observations at each time point, but with an additional pena...
computer science
22,278
Predictive Entropy Search for Multi-objective Bayesian Optimization
stat.ML
We present PESMO, a Bayesian method for identifying the Pareto set of multi-objective optimization problems, when the functions are expensive to evaluate. The central idea of PESMO is to choose evaluation points so as to maximally reduce the entropy of the posterior distribution over the Pareto set. Critically, the PES...
computer science
22,279
The Kernel Two-Sample Test for Brain Networks
stat.ML
In clinical and neuroscientific studies, systematic differences between two populations of brain networks are investigated in order to characterize mental diseases or processes. Those networks are usually represented as graphs built from neuroimaging data and studied by means of graph analysis methods. The typical mach...
computer science
22,280
PLDA with Two Sources of Inter-session Variability
stat.ML
In some speaker recognition scenarios we find conversations recorded simultaneously over multiple channels. That is the case of the interviews in the NIST SRE dataset. To take advantage of that, we propose a modification of the PLDA model that considers two different inter-session variability terms. The first term is t...
computer science
22,281
Stochastic Parallel Block Coordinate Descent for Large-scale Saddle Point Problems
stat.ML
We consider convex-concave saddle point problems with a separable structure and non-strongly convex functions. We propose an efficient stochastic block coordinate descent method using adaptive primal-dual updates, which enables flexible parallel optimization for large-scale problems. Our method shares the efficiency an...
computer science
22,282
Bayesian SPLDA
stat.ML
In this document we are going to derive the equations needed to implement a Variational Bayes estimation of the parameters of the simplified probabilistic linear discriminant analysis (SPLDA) model. This can be used to adapt SPLDA from one database to another with few development data or to implement the fully Bayesian...
computer science
22,283
Black box variational inference for state space models
stat.ML
Latent variable time-series models are among the most heavily used tools from machine learning and applied statistics. These models have the advantage of learning latent structure both from noisy observations and from the temporal ordering in the data, where it is assumed that meaningful correlation structure exists ac...
computer science
22,284
Unsupervised Adaptation of SPLDA
stat.ML
State-of-the-art speaker recognition relays on models that need a large amount of training data. This models are successful in tasks like NIST SRE because there is sufficient data available. However, in real applications, we usually do not have so much data and, in many cases, the speaker labels are unknown. We present...
computer science
22,285
Variational Bayes Factor Analysis for i-Vector Extraction
stat.ML
In this document we are going to derive the equations needed to implement a Variational Bayes i-vector extractor. This can be used to extract longer i-vectors reducing the risk of overfittig or to adapt an i-vector extractor from a database to another with scarce development data. This work is based on Patrick Kenny's ...
computer science
22,286
Statistical Properties of the Single Linkage Hierarchical Clustering Estimator
stat.ML
Distance-based hierarchical clustering (HC) methods are widely used in unsupervised data analysis but few authors take account of uncertainty in the distance data. We incorporate a statistical model of the uncertainty through corruption or noise in the pairwise distances and investigate the problem of estimating the HC...
computer science
22,287
Maximum Likelihood Estimation for Single Linkage Hierarchical Clustering
stat.ML
We derive a statistical model for estimation of a dendrogram from single linkage hierarchical clustering (SLHC) that takes account of uncertainty through noise or corruption in the measurements of separation of data. Our focus is on just the estimation of the hierarchy of partitions afforded by the dendrogram, rather t...
computer science
22,288
Gradient Estimation with Simultaneous Perturbation and Compressive Sensing
stat.ML
This paper aims at achieving a "good" estimator for the gradient of a function on a high-dimensional space. Often such functions are not sensitive in all coordinates and the gradient of the function is almost sparse. We propose a method for gradient estimation that combines ideas from Spall's Simultaneous Perturbation ...
computer science
22,289
A General Framework for Constrained Bayesian Optimization using Information-based Search
stat.ML
We present an information-theoretic framework for solving global black-box optimization problems that also have black-box constraints. Of particular interest to us is to efficiently solve problems with decoupled constraints, in which subsets of the objective and constraint functions may be evaluated independently. For ...
computer science
22,290
Highly Scalable Tensor Factorization for Prediction of Drug-Protein Interaction Type
stat.ML
The understanding of the type of inhibitory interaction plays an important role in drug design. Therefore, researchers are interested to know whether a drug has competitive or non-competitive interaction to particular protein targets. Method: to analyze the interaction types we propose factorization method Macau whic...
computer science
22,291
Adjusting for Chance Clustering Comparison Measures
stat.ML
Adjusted for chance measures are widely used to compare partitions/clusterings of the same data set. In particular, the Adjusted Rand Index (ARI) based on pair-counting, and the Adjusted Mutual Information (AMI) based on Shannon information theory are very popular in the clustering community. Nonetheless it is an open ...
computer science
22,292
Stochastic Collapsed Variational Inference for Hidden Markov Models
stat.ML
Stochastic variational inference for collapsed models has recently been successfully applied to large scale topic modelling. In this paper, we propose a stochastic collapsed variational inference algorithm for hidden Markov models, in a sequential data setting. Given a collapsed hidden Markov Model, we break its long M...
computer science
22,293
Stochastic Collapsed Variational Inference for Sequential Data
stat.ML
Stochastic variational inference for collapsed models has recently been successfully applied to large scale topic modelling. In this paper, we propose a stochastic collapsed variational inference algorithm in the sequential data setting. Our algorithm is applicable to both finite hidden Markov models and hierarchical D...
computer science
22,294
Learning population and subject-specific brain connectivity networks via Mixed Neighborhood Selection
stat.ML
In neuroimaging data analysis, Gaussian graphical models are often used to model statistical dependencies across spatially remote brain regions known as functional connectivity. Typically, data is collected across a cohort of subjects and the scientific objectives consist of estimating population and subject-specific g...
computer science
22,295
Gibbs-type Indian buffet processes
stat.ML
We investigate a class of feature allocation models that generalize the Indian buffet process and are parameterized by Gibbs-type random measures. Two existing classes are contained as special cases: the original two-parameter Indian buffet process, corresponding to the Dirichlet process, and the stable (or three-param...
computer science
22,296
Inference in topic models: sparsity and trade-off
stat.ML
Topic models are popular for modeling discrete data (e.g., texts, images, videos, links), and provide an efficient way to discover hidden structures/semantics in massive data. One of the core problems in this field is the posterior inference for individual data instances. This problem is particularly important in strea...
computer science
22,297
Guaranteed inference in topic models
stat.ML
One of the core problems in statistical models is the estimation of a posterior distribution. For topic models, the problem of posterior inference for individual texts is particularly important, especially when dealing with data streams, but is often intractable in the worst case. As a consequence, existing methods for...
computer science
22,298
Cross-Validated Variable Selection in Tree-Based Methods Improves Predictive Performance
stat.ML
Recursive partitioning approaches producing tree-like models are a long standing staple of predictive modeling, in the last decade mostly as ``sub-learners'' within state of the art ensemble methods like Boosting and Random Forest. However, a fundamental flaw in the partitioning (or splitting) rule of commonly used tre...
computer science
22,299
Relative Density and Exact Recovery in Heterogeneous Stochastic Block Models
stat.ML
The Stochastic Block Model (SBM) is a widely used random graph model for networks with communities. Despite the recent burst of interest in recovering communities in the SBM from statistical and computational points of view, there are still gaps in understanding the fundamental information theoretic and computational l...
computer science
22,300
Learning a Hybrid Architecture for Sequence Regression and Annotation
stat.ML
When learning a hidden Markov model (HMM), sequen- tial observations can often be complemented by real-valued summary response variables generated from the path of hid- den states. Such settings arise in numerous domains, includ- ing many applications in biology, like motif discovery and genome annotation. In this pape...
computer science
22,301
A Theoretically Grounded Application of Dropout in Recurrent Neural Networks
stat.ML
Recurrent neural networks (RNNs) stand at the forefront of many recent developments in deep learning. Yet a major difficulty with these models is their tendency to overfit, with dropout shown to fail when applied to recurrent layers. Recent results at the intersection of Bayesian modelling and deep learning offer a Bay...
computer science