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2,300
Pooling homogeneous ensembles to build heterogeneous ensembles
cs.LG
In ensemble methods, the outputs of a collection of diverse classifiers are combined in the expectation that the global prediction be more accurate than the individual ones. Heterogeneous ensembles consist of predictors of different types, which are likely to have different biases. If these biases are complementary, th...
computer science
2,301
Learning to Make Predictions on Graphs with Autoencoders
cs.LG
We examine two fundamental tasks associated with graph representation learning: link prediction and semi-supervised node classification. We present a densely connected autoencoder architecture capable of learning a joint representation of both local graph structure and available external node features for the multi-tas...
computer science
2,302
Learning Optimal Policies from Observational Data
cs.AI
Choosing optimal (or at least better) policies is an important problem in domains from medicine to education to finance and many others. One approach to this problem is through controlled experiments/trials - but controlled experiments are expensive. Hence it is important to choose the best policies on the basis of obs...
computer science
2,303
Learning with Abandonment
stat.ML
Consider a platform that wants to learn a personalized policy for each user, but the platform faces the risk of a user abandoning the platform if she is dissatisfied with the actions of the platform. For example, a platform is interested in personalizing the number of newsletters it sends, but faces the risk that the u...
computer science
2,304
DID: Distributed Incremental Block Coordinate Descent for Nonnegative Matrix Factorization
cs.LG
Nonnegative matrix factorization (NMF) has attracted much attention in the last decade as a dimension reduction method in many applications. Due to the explosion in the size of data, naturally the samples are collected and stored distributively in local computational nodes. Thus, there is a growing need to develop algo...
computer science
2,305
Variance Reduction Methods for Sublinear Reinforcement Learning
cs.AI
This work considers the problem of provably optimal reinforcement learning for (episodic) finite horizon MDPs, i.e. how an agent learns to maximize his/her (long term) reward in an uncertain environment. The main contribution is in providing a novel algorithm --- Variance-reduced Upper Confidence Q-learning (vUCQ) --- ...
computer science
2,306
Modeling reverse thinking for machine learning
cs.LG
Human inertial thinking schemes can be formed through learning, which are then applied to quickly solve similar problems later. However, when problems are significantly different, inertial thinking generally presents the solutions that are definitely imperfect. In such cases, people will apply creative thinking, such a...
computer science
2,307
Vector Quantization as Sparse Least Square Optimization
cs.LG
Vector quantization aims to form new vectors/matrices with shared values close to the original. It could compress data with acceptable information loss, and could be of great usefulness in areas like Image Processing, Pattern Recognition and Machine Learning. In recent years, the importance of quantization has been soa...
computer science
2,308
Hierarchical Imitation and Reinforcement Learning
cs.LG
We study the problem of learning policies over long time horizons. We present a framework that leverages and integrates two key concepts. First, we utilize hierarchical policy classes that enable planning over different time scales, i.e., the high level planner proposes a sequence of subgoals for the low level planner ...
computer science
2,309
Understanding the Loss Surface of Neural Networks for Binary Classification
cs.LG
It is widely conjectured that the reason that training algorithms for neural networks are successful because all local minima lead to similar performance, for example, see (LeCun et al., 2015, Choromanska et al., 2015, Dauphin et al., 2014). Performance is typically measured in terms of two metrics: training performanc...
computer science
2,310
On the Power of Over-parametrization in Neural Networks with Quadratic Activation
cs.LG
We provide new theoretical insights on why over-parametrization is effective in learning neural networks. For a $k$ hidden node shallow network with quadratic activation and $n$ training data points, we show as long as $ k \ge \sqrt{2n}$, over-parametrization enables local search algorithms to find a \emph{globally} op...
computer science
2,311
Improving Multi-Step Traffic Flow Prediction
cs.AI
In its simplest form, the traffic flow prediction problem is restricted to predicting a single time-step into the future. Multi-step traffic flow prediction extends this set-up to the case where predicting multiple time-steps into the future based on some finite history is of interest. This problem is significantly mor...
computer science
2,312
On Discrimination Discovery and Removal in Ranked Data using Causal Graph
cs.LG
Predictive models learned from historical data are widely used to help companies and organizations make decisions. However, they may digitally unfairly treat unwanted groups, raising concerns about fairness and discrimination. In this paper, we study the fairness-aware ranking problem which aims to discover discriminat...
computer science
2,313
A Multi-Objective Deep Reinforcement Learning Framework
cs.LG
This paper presents a new multi-objective deep reinforcement learning (MODRL) framework based on deep Q-networks. We propose linear and non-linear methods to develop the MODRL framework that includes both single-policy and multi-policy strategies. The experimental results on a deep sea treasure environment indicate tha...
computer science
2,314
Deep Neural Network Compression with Single and Multiple Level Quantization
cs.LG
Network quantization is an effective solution to compress deep neural networks for practical usage. Existing network quantization methods cannot sufficiently exploit the depth information to generate low-bit compressed network. In this paper, we propose two novel network quantization approaches, single-level network qu...
computer science
2,315
Hierarchical Reinforcement Learning: Approximating Optimal Discounted TSP Using Local Policies
cs.LG
In this work, we provide theoretical guarantees for reward decomposition in deterministic MDPs. Reward decomposition is a special case of Hierarchical Reinforcement Learning, that allows one to learn many policies in parallel and combine them into a composite solution. Our approach builds on mapping this problem into a...
computer science
2,316
Soft-Robust Actor-Critic Policy-Gradient
cs.LG
Robust Reinforcement Learning aims to derive an optimal behavior that accounts for model uncertainty in dynamical systems. However, previous studies have shown that by considering the worst case scenario, robust policies can be overly conservative. Our \textit{soft-robust} framework is an attempt to overcome this issue...
computer science
2,317
Imitation Learning with Concurrent Actions in 3D Games
cs.AI
In this work we describe a novel deep reinforcement learning neural network architecture that allows multiple actions to be selected at every time-step. Multi-action policies allows complex behaviors to be learnt that are otherwise hard to achieve when using single action selection techniques. This work describes an al...
computer science
2,318
Setting up a Reinforcement Learning Task with a Real-World Robot
cs.LG
Reinforcement learning is a promising approach to developing hard-to-engineer adaptive solutions for complex and diverse robotic tasks. However, learning with real-world robots is often unreliable and difficult, which resulted in their low adoption in reinforcement learning research. This difficulty is worsened by the ...
computer science
2,319
Regret Bounds for Opportunistic Channel Access
stat.ML
We consider the task of opportunistic channel access in a primary system composed of independent Gilbert-Elliot channels where the secondary (or opportunistic) user does not dispose of a priori information regarding the statistical characteristics of the system. It is shown that this problem may be cast into the framew...
computer science
2,320
Feature Selection with Conjunctions of Decision Stumps and Learning from Microarray Data
cs.LG
One of the objectives of designing feature selection learning algorithms is to obtain classifiers that depend on a small number of attributes and have verifiable future performance guarantees. There are few, if any, approaches that successfully address the two goals simultaneously. Performance guarantees become crucial...
computer science
2,321
On the Estimation of Coherence
stat.ML
Low-rank matrix approximations are often used to help scale standard machine learning algorithms to large-scale problems. Recently, matrix coherence has been used to characterize the ability to extract global information from a subset of matrix entries in the context of these low-rank approximations and other sampling-...
computer science
2,322
Rapid Feature Learning with Stacked Linear Denoisers
cs.LG
We investigate unsupervised pre-training of deep architectures as feature generators for "shallow" classifiers. Stacked Denoising Autoencoders (SdA), when used as feature pre-processing tools for SVM classification, can lead to significant improvements in accuracy - however, at the price of a substantial increase in co...
computer science
2,323
Efficient Optimal Learning for Contextual Bandits
cs.LG
We address the problem of learning in an online setting where the learner repeatedly observes features, selects among a set of actions, and receives reward for the action taken. We provide the first efficient algorithm with an optimal regret. Our algorithm uses a cost sensitive classification learner as an oracle and h...
computer science
2,324
A review and comparison of strategies for multi-step ahead time series forecasting based on the NN5 forecasting competition
stat.ML
Multi-step ahead forecasting is still an open challenge in time series forecasting. Several approaches that deal with this complex problem have been proposed in the literature but an extensive comparison on a large number of tasks is still missing. This paper aims to fill this gap by reviewing existing strategies for m...
computer science
2,325
Overlapping Mixtures of Gaussian Processes for the Data Association Problem
stat.ML
In this work we introduce a mixture of GPs to address the data association problem, i.e. to label a group of observations according to the sources that generated them. Unlike several previously proposed GP mixtures, the novel mixture has the distinct characteristic of using no gating function to determine the associati...
computer science
2,326
Improving parameter learning of Bayesian nets from incomplete data
cs.LG
This paper addresses the estimation of parameters of a Bayesian network from incomplete data. The task is usually tackled by running the Expectation-Maximization (EM) algorithm several times in order to obtain a high log-likelihood estimate. We argue that choosing the maximum log-likelihood estimate (as well as the max...
computer science
2,327
UPAL: Unbiased Pool Based Active Learning
stat.ML
In this paper we address the problem of pool based active learning, and provide an algorithm, called UPAL, that works by minimizing the unbiased estimator of the risk of a hypothesis in a given hypothesis space. For the space of linear classifiers and the squared loss we show that UPAL is equivalent to an exponentially...
computer science
2,328
Learning High-Dimensional Mixtures of Graphical Models
stat.ML
We consider unsupervised estimation of mixtures of discrete graphical models, where the class variable corresponding to the mixture components is hidden and each mixture component over the observed variables can have a potentially different Markov graph structure and parameters. We propose a novel approach for estimati...
computer science
2,329
An Online Learning-based Framework for Tracking
cs.LG
We study the tracking problem, namely, estimating the hidden state of an object over time, from unreliable and noisy measurements. The standard framework for the tracking problem is the generative framework, which is the basis of solutions such as the Bayesian algorithm and its approximation, the particle filters. Howe...
computer science
2,330
Real-Time Scheduling via Reinforcement Learning
cs.LG
Cyber-physical systems, such as mobile robots, must respond adaptively to dynamic operating conditions. Effective operation of these systems requires that sensing and actuation tasks are performed in a timely manner. Additionally, execution of mission specific tasks such as imaging a room must be balanced against the n...
computer science
2,331
Causal Conclusions that Flip Repeatedly and Their Justification
cs.LG
Over the past two decades, several consistent procedures have been designed to infer causal conclusions from observational data. We prove that if the true causal network might be an arbitrary, linear Gaussian network or a discrete Bayes network, then every unambiguous causal conclusion produced by a consistent method f...
computer science
2,332
Irregular-Time Bayesian Networks
cs.AI
In many fields observations are performed irregularly along time, due to either measurement limitations or lack of a constant immanent rate. While discrete-time Markov models (as Dynamic Bayesian Networks) introduce either inefficient computation or an information loss to reasoning about such processes, continuous-time...
computer science
2,333
Modeling Events with Cascades of Poisson Processes
cs.LG
We present a probabilistic model of events in continuous time in which each event triggers a Poisson process of successor events. The ensemble of observed events is thereby modeled as a superposition of Poisson processes. Efficient inference is feasible under this model with an EM algorithm. Moreover, the EM algorithm ...
computer science
2,334
Bayesian Inference in Monte-Carlo Tree Search
cs.LG
Monte-Carlo Tree Search (MCTS) methods are drawing great interest after yielding breakthrough results in computer Go. This paper proposes a Bayesian approach to MCTS that is inspired by distributionfree approaches such as UCT [13], yet significantly differs in important respects. The Bayesian framework allows potential...
computer science
2,335
Primal View on Belief Propagation
cs.LG
It is known that fixed points of loopy belief propagation (BP) correspond to stationary points of the Bethe variational problem, where we minimize the Bethe free energy subject to normalization and marginalization constraints. Unfortunately, this does not entirely explain BP because BP is a dual rather than primal algo...
computer science
2,336
Modeling Multiple Annotator Expertise in the Semi-Supervised Learning Scenario
cs.LG
Learning algorithms normally assume that there is at most one annotation or label per data point. However, in some scenarios, such as medical diagnosis and on-line collaboration,multiple annotations may be available. In either case, obtaining labels for data points can be expensive and time-consuming (in some circumsta...
computer science
2,337
A Convex Formulation for Learning Task Relationships in Multi-Task Learning
cs.LG
Multi-task learning is a learning paradigm which seeks to improve the generalization performance of a learning task with the help of some other related tasks. In this paper, we propose a regularization formulation for learning the relationships between tasks in multi-task learning. This formulation can be viewed as a n...
computer science
2,338
Learning Feature Hierarchies with Centered Deep Boltzmann Machines
stat.ML
Deep Boltzmann machines are in principle powerful models for extracting the hierarchical structure of data. Unfortunately, attempts to train layers jointly (without greedy layer-wise pretraining) have been largely unsuccessful. We propose a modification of the learning algorithm that initially recenters the output of t...
computer science
2,339
Transforming Graph Representations for Statistical Relational Learning
stat.ML
Relational data representations have become an increasingly important topic due to the recent proliferation of network datasets (e.g., social, biological, information networks) and a corresponding increase in the application of statistical relational learning (SRL) algorithms to these domains. In this article, we exami...
computer science
2,340
The threshold EM algorithm for parameter learning in bayesian network with incomplete data
cs.AI
Bayesian networks (BN) are used in a big range of applications but they have one issue concerning parameter learning. In real application, training data are always incomplete or some nodes are hidden. To deal with this problem many learning parameter algorithms are suggested foreground EM, Gibbs sampling and RBE algori...
computer science
2,341
Interpolating Conditional Density Trees
cs.LG
Joint distributions over many variables are frequently modeled by decomposing them into products of simpler, lower-dimensional conditional distributions, such as in sparsely connected Bayesian networks. However, automatically learning such models can be very computationally expensive when there are many datapoints and ...
computer science
2,342
Discriminative Probabilistic Models for Relational Data
cs.LG
In many supervised learning tasks, the entities to be labeled are related to each other in complex ways and their labels are not independent. For example, in hypertext classification, the labels of linked pages are highly correlated. A standard approach is to classify each entity independently, ignoring the correlation...
computer science
2,343
IPF for Discrete Chain Factor Graphs
cs.LG
Iterative Proportional Fitting (IPF), combined with EM, is commonly used as an algorithm for likelihood maximization in undirected graphical models. In this paper, we present two iterative algorithms that generalize upon IPF. The first one is for likelihood maximization in discrete chain factor graphs, which we define ...
computer science
2,344
Automated Variational Inference in Probabilistic Programming
stat.ML
We present a new algorithm for approximate inference in probabilistic programs, based on a stochastic gradient for variational programs. This method is efficient without restrictions on the probabilistic program; it is particularly practical for distributions which are not analytically tractable, including highly struc...
computer science
2,345
Conditions Under Which Conditional Independence and Scoring Methods Lead to Identical Selection of Bayesian Network Models
cs.AI
It is often stated in papers tackling the task of inferring Bayesian network structures from data that there are these two distinct approaches: (i) Apply conditional independence tests when testing for the presence or otherwise of edges; (ii) Search the model space using a scoring metric. Here I argue that for complete...
computer science
2,346
Learning the Dimensionality of Hidden Variables
cs.LG
A serious problem in learning probabilistic models is the presence of hidden variables. These variables are not observed, yet interact with several of the observed variables. Detecting hidden variables poses two problems: determining the relations to other variables in the model and determining the number of states of ...
computer science
2,347
Multivariate Information Bottleneck
cs.LG
The Information bottleneck method is an unsupervised non-parametric data organization technique. Given a joint distribution P(A,B), this method constructs a new variable T that extracts partitions, or clusters, over the values of A that are informative about B. The information bottleneck has already been applied to doc...
computer science
2,348
Estimating Well-Performing Bayesian Networks using Bernoulli Mixtures
cs.LG
A novel method for estimating Bayesian network (BN) parameters from data is presented which provides improved performance on test data. Previous research has shown the value of representing conditional probability distributions (CPDs) via neural networks(Neal 1992), noisy-OR gates (Neal 1992, Diez 1993)and decision tre...
computer science
2,349
Improved learning of Bayesian networks
cs.LG
The search space of Bayesian Network structures is usually defined as Acyclic Directed Graphs (DAGs) and the search is done by local transformations of DAGs. But the space of Bayesian Networks is ordered by DAG Markov model inclusion and it is natural to consider that a good search policy should take this into account....
computer science
2,350
Maximum Likelihood Bounded Tree-Width Markov Networks
cs.LG
Chow and Liu (1968) studied the problem of learning a maximumlikelihood Markov tree. We generalize their work to more complexMarkov networks by considering the problem of learning a maximumlikelihood Markov network of bounded complexity. We discuss howtree-width is in many ways the appropriate measure of complexity and...
computer science
2,351
The Optimal Reward Baseline for Gradient-Based Reinforcement Learning
cs.LG
There exist a number of reinforcement learning algorithms which learnby climbing the gradient of expected reward. Their long-runconvergence has been proved, even in partially observableenvironments with non-deterministic actions, and without the need fora system model. However, the variance of the gradient estimator ha...
computer science
2,352
Statistical Modeling in Continuous Speech Recognition (CSR)(Invited Talk)
cs.LG
Automatic continuous speech recognition (CSR) is sufficiently mature that a variety of real world applications are now possible including large vocabulary transcription and interactive spoken dialogues. This paper reviews the evolution of the statistical modelling techniques which underlie current-day systems, specific...
computer science
2,353
Dynamic Bayesian Multinets
cs.LG
In this work, dynamic Bayesian multinets are introduced where a Markov chain state at time t determines conditional independence patterns between random variables lying within a local time window surrounding t. It is shown how information-theoretic criterion functions can be used to induce sparse, discriminative, and c...
computer science
2,354
Being Bayesian about Network Structure
cs.LG
In many domains, we are interested in analyzing the structure of the underlying distribution, e.g., whether one variable is a direct parent of the other. Bayesian model-selection attempts to find the MAP model and use its structure to answer these questions. However, when the amount of available data is modest, there m...
computer science
2,355
Gaussian Process Networks
cs.AI
In this paper we address the problem of learning the structure of a Bayesian network in domains with continuous variables. This task requires a procedure for comparing different candidate structures. In the Bayesian framework, this is done by evaluating the {em marginal likelihood/} of the data given a candidate struct...
computer science
2,356
Tractable Bayesian Learning of Tree Belief Networks
cs.LG
In this paper we present decomposable priors, a family of priors over structure and parameters of tree belief nets for which Bayesian learning with complete observations is tractable, in the sense that the posterior is also decomposable and can be completely determined analytically in polynomial time. This follows from...
computer science
2,357
Adaptive Importance Sampling for Estimation in Structured Domains
cs.AI
Sampling is an important tool for estimating large, complex sums and integrals over high dimensional spaces. For instance, important sampling has been used as an alternative to exact methods for inference in belief networks. Ideally, we want to have a sampling distribution that provides optimal-variance estimators. In ...
computer science
2,358
Dynamic Trees: A Structured Variational Method Giving Efficient Propagation Rules
cs.LG
Dynamic trees are mixtures of tree structured belief networks. They solve some of the problems of fixed tree networks at the cost of making exact inference intractable. For this reason approximate methods such as sampling or mean field approaches have been used. However, mean field approximations assume a factorized di...
computer science
2,359
A Branch-and-Bound Algorithm for MDL Learning Bayesian Networks
cs.AI
This paper extends the work in [Suzuki, 1996] and presents an efficient depth-first branch-and-bound algorithm for learning Bayesian network structures, based on the minimum description length (MDL) principle, for a given (consistent) variable ordering. The algorithm exhaustively searches through all network structures...
computer science
2,360
Model-Based Hierarchical Clustering
cs.LG
We present an approach to model-based hierarchical clustering by formulating an objective function based on a Bayesian analysis. This model organizes the data into a cluster hierarchy while specifying a complex feature-set partitioning that is a key component of our model. Features can have either a unique distribution...
computer science
2,361
Variational Approximations between Mean Field Theory and the Junction Tree Algorithm
cs.LG
Recently, variational approximations such as the mean field approximation have received much interest. We extend the standard mean field method by using an approximating distribution that factorises into cluster potentials. This includes undirected graphs, directed acyclic graphs and junction trees. We derive generaliz...
computer science
2,362
Multi-class Generalized Binary Search for Active Inverse Reinforcement Learning
cs.LG
This paper addresses the problem of learning a task from demonstration. We adopt the framework of inverse reinforcement learning, where tasks are represented in the form of a reward function. Our contribution is a novel active learning algorithm that enables the learning agent to query the expert for more informative d...
computer science
2,363
Comparing Bayesian Network Classifiers
cs.LG
In this paper, we empirically evaluate algorithms for learning four types of Bayesian network (BN) classifiers - Naive-Bayes, tree augmented Naive-Bayes, BN augmented Naive-Bayes and general BNs, where the latter two are learned using two variants of a conditional-independence (CI) based BN-learning algorithm. Experime...
computer science
2,364
Data Analysis with Bayesian Networks: A Bootstrap Approach
cs.LG
In recent years there has been significant progress in algorithms and methods for inducing Bayesian networks from data. However, in complex data analysis problems, we need to go beyond being satisfied with inducing networks with high scores. We need to provide confidence measures on features of these networks: Is the e...
computer science
2,365
A Bayesian Network Classifier that Combines a Finite Mixture Model and a Naive Bayes Model
cs.LG
In this paper we present a new Bayesian network model for classification that combines the naive-Bayes (NB) classifier and the finite-mixture (FM) classifier. The resulting classifier aims at relaxing the strong assumptions on which the two component models are based, in an attempt to improve on their classification pe...
computer science
2,366
Learning Bayesian Networks with Restricted Causal Interactions
cs.AI
A major problem for the learning of Bayesian networks (BNs) is the exponential number of parameters needed for conditional probability tables. Recent research reduces this complexity by modeling local structure in the probability tables. We examine the use of log-linear local models. While log-linear models in this con...
computer science
2,367
The Bayesian Structural EM Algorithm
cs.LG
In recent years there has been a flurry of works on learning Bayesian networks from data. One of the hard problems in this area is how to effectively learn the structure of a belief network from incomplete data- that is, in the presence of missing values or hidden variables. In a recent paper, I introduced an algorithm...
computer science
2,368
Learning Mixtures of DAG Models
cs.LG
We describe computationally efficient methods for learning mixtures in which each component is a directed acyclic graphical model (mixtures of DAGs or MDAGs). We argue that simple search-and-score algorithms are infeasible for a variety of problems, and introduce a feasible approach in which parameter and structure sea...
computer science
2,369
Multiple decision trees
cs.LG
This paper describes experiments, on two domains, to investigate the effect of averaging over predictions of multiple decision trees, instead of using a single tree. Other authors have pointed out theoretical and commonsense reasons for preferring the multiple tree approach. Ideally, we would like to consider predictio...
computer science
2,370
An Algorithm for Training Polynomial Networks
cs.LG
We consider deep neural networks, in which the output of each node is a quadratic function of its inputs. Similar to other deep architectures, these networks can compactly represent any function on a finite training set. The main goal of this paper is the derivation of an efficient layer-by-layer algorithm for training...
computer science
2,371
Online Learning under Delayed Feedback
cs.LG
Online learning with delayed feedback has received increasing attention recently due to its several applications in distributed, web-based learning problems. In this paper we provide a systematic study of the topic, and analyze the effect of delay on the regret of online learning algorithms. Somewhat surprisingly, it t...
computer science
2,372
KL-based Control of the Learning Schedule for Surrogate Black-Box Optimization
cs.LG
This paper investigates the control of an ML component within the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) devoted to black-box optimization. The known CMA-ES weakness is its sample complexity, the number of evaluations of the objective function needed to approximate the global optimum. This weakness is...
computer science
2,373
Efficient Learning of Generalized Linear and Single Index Models with Isotonic Regression
cs.AI
Generalized Linear Models (GLMs) and Single Index Models (SIMs) provide powerful generalizations of linear regression, where the target variable is assumed to be a (possibly unknown) 1-dimensional function of a linear predictor. In general, these problems entail non-convex estimation procedures, and, in practice, itera...
computer science
2,374
Bayesian Inference with Posterior Regularization and applications to Infinite Latent SVMs
cs.LG
Existing Bayesian models, especially nonparametric Bayesian methods, rely on specially conceived priors to incorporate domain knowledge for discovering improved latent representations. While priors can affect posterior distributions through Bayes' rule, imposing posterior regularization is arguably more direct and in s...
computer science
2,375
Information fusion in multi-task Gaussian processes
stat.ML
This paper evaluates heterogeneous information fusion using multi-task Gaussian processes in the context of geological resource modeling. Specifically, it empirically demonstrates that information integration across heterogeneous information sources leads to superior estimates of all the quantities being modeled, compa...
computer science
2,376
The Kernel Pitman-Yor Process
cs.LG
In this work, we propose the kernel Pitman-Yor process (KPYP) for nonparametric clustering of data with general spatial or temporal interdependencies. The KPYP is constructed by first introducing an infinite sequence of random locations. Then, based on the stick-breaking construction of the Pitman-Yor process, we defin...
computer science
2,377
An Efficient Message-Passing Algorithm for the M-Best MAP Problem
cs.AI
Much effort has been directed at algorithms for obtaining the highest probability configuration in a probabilistic random field model known as the maximum a posteriori (MAP) inference problem. In many situations, one could benefit from having not just a single solution, but the top M most probable solutions known as th...
computer science
2,378
Hilbert Space Embeddings of POMDPs
cs.LG
A nonparametric approach for policy learning for POMDPs is proposed. The approach represents distributions over the states, observations, and actions as embeddings in feature spaces, which are reproducing kernel Hilbert spaces. Distributions over states given the observations are obtained by applying the kernel Bayes' ...
computer science
2,379
Learning STRIPS Operators from Noisy and Incomplete Observations
cs.LG
Agents learning to act autonomously in real-world domains must acquire a model of the dynamics of the domain in which they operate. Learning domain dynamics can be challenging, especially where an agent only has partial access to the world state, and/or noisy external sensors. Even in standard STRIPS domains, existing ...
computer science
2,380
Closed-Form Learning of Markov Networks from Dependency Networks
cs.LG
Markov networks (MNs) are a powerful way to compactly represent a joint probability distribution, but most MN structure learning methods are very slow, due to the high cost of evaluating candidates structures. Dependency networks (DNs) represent a probability distribution as a set of conditional probability distributio...
computer science
2,381
An Improved Admissible Heuristic for Learning Optimal Bayesian Networks
cs.AI
Recently two search algorithms, A* and breadth-first branch and bound (BFBnB), were developed based on a simple admissible heuristic for learning Bayesian network structures that optimize a scoring function. The heuristic represents a relaxation of the learning problem such that each variable chooses optimal parents in...
computer science
2,382
Advances in Learning Bayesian Networks of Bounded Treewidth
cs.AI
This work presents novel algorithms for learning Bayesian network structures with bounded treewidth. Both exact and approximate methods are developed. The exact method combines mixed-integer linear programming formulations for structure learning and treewidth computation. The approximate method consists in uniformly sa...
computer science
2,383
ExpertBayes: Automatically refining manually built Bayesian networks
cs.AI
Bayesian network structures are usually built using only the data and starting from an empty network or from a naive Bayes structure. Very often, in some domains, like medicine, a prior structure knowledge is already known. This structure can be automatically or manually refined in search for better performance models....
computer science
2,384
Notes on hierarchical ensemble methods for DAG-structured taxonomies
cs.AI
Several real problems ranging from text classification to computational biology are characterized by hierarchical multi-label classification tasks. Most of the methods presented in literature focused on tree-structured taxonomies, but only few on taxonomies structured according to a Directed Acyclic Graph (DAG). In thi...
computer science
2,385
Efficient Learning in Large-Scale Combinatorial Semi-Bandits
cs.LG
A stochastic combinatorial semi-bandit is an online learning problem where at each step a learning agent chooses a subset of ground items subject to combinatorial constraints, and then observes stochastic weights of these items and receives their sum as a payoff. In this paper, we consider efficient learning in large-s...
computer science
2,386
Efficient Bayes-Adaptive Reinforcement Learning using Sample-Based Search
cs.LG
Bayesian model-based reinforcement learning is a formally elegant approach to learning optimal behaviour under model uncertainty, trading off exploration and exploitation in an ideal way. Unfortunately, finding the resulting Bayes-optimal policies is notoriously taxing, since the search space becomes enormous. In this ...
computer science
2,387
Learning Bayesian Network Parameters with Prior Knowledge about Context-Specific Qualitative Influences
cs.AI
We present a method for learning the parameters of a Bayesian network with prior knowledge about the signs of influences between variables. Our method accommodates not just the standard signs, but provides for context-specific signs as well. We show how the various signs translate into order constraints on the network ...
computer science
2,388
Ordering-Based Search: A Simple and Effective Algorithm for Learning Bayesian Networks
cs.LG
One of the basic tasks for Bayesian networks (BNs) is that of learning a network structure from data. The BN-learning problem is NP-hard, so the standard solution is heuristic search. Many approaches have been proposed for this task, but only a very small number outperform the baseline of greedy hill-climbing with tabu...
computer science
2,389
MOB-ESP and other Improvements in Probability Estimation
cs.LG
A key prerequisite to optimal reasoning under uncertainty in intelligent systems is to start with good class probability estimates. This paper improves on the current best probability estimation trees (Bagged-PETs) and also presents a new ensemble-based algorithm (MOB-ESP). Comparisons are made using several benchmark ...
computer science
2,390
Meta-Learning of Exploration/Exploitation Strategies: The Multi-Armed Bandit Case
cs.AI
The exploration/exploitation (E/E) dilemma arises naturally in many subfields of Science. Multi-armed bandit problems formalize this dilemma in its canonical form. Most current research in this field focuses on generic solutions that can be applied to a wide range of problems. However, in practice, it is often the case...
computer science
2,391
Learning AMP Chain Graphs and some Marginal Models Thereof under Faithfulness: Extended Version
stat.ML
This paper deals with chain graphs under the Andersson-Madigan-Perlman (AMP) interpretation. In particular, we present a constraint based algorithm for learning an AMP chain graph a given probability distribution is faithful to. Moreover, we show that the extension of Meek's conjecture to AMP chain graphs does not hold...
computer science
2,392
A Greedy Approximation of Bayesian Reinforcement Learning with Probably Optimistic Transition Model
cs.AI
Bayesian Reinforcement Learning (RL) is capable of not only incorporating domain knowledge, but also solving the exploration-exploitation dilemma in a natural way. As Bayesian RL is intractable except for special cases, previous work has proposed several approximation methods. However, these methods are usually too sen...
computer science
2,393
SparsityBoost: A New Scoring Function for Learning Bayesian Network Structure
cs.LG
We give a new consistent scoring function for structure learning of Bayesian networks. In contrast to traditional approaches to scorebased structure learning, such as BDeu or MDL, the complexity penalty that we propose is data-dependent and is given by the probability that a conditional independence test correctly show...
computer science
2,394
Bethe-ADMM for Tree Decomposition based Parallel MAP Inference
cs.AI
We consider the problem of maximum a posteriori (MAP) inference in discrete graphical models. We present a parallel MAP inference algorithm called Bethe-ADMM based on two ideas: tree-decomposition of the graph and the alternating direction method of multipliers (ADMM). However, unlike the standard ADMM, we use an inexa...
computer science
2,395
Cyclic Causal Discovery from Continuous Equilibrium Data
cs.LG
We propose a method for learning cyclic causal models from a combination of observational and interventional equilibrium data. Novel aspects of the proposed method are its ability to work with continuous data (without assuming linearity) and to deal with feedback loops. Within the context of biochemical reactions, we a...
computer science
2,396
Identifying Finite Mixtures of Nonparametric Product Distributions and Causal Inference of Confounders
cs.LG
We propose a kernel method to identify finite mixtures of nonparametric product distributions. It is based on a Hilbert space embedding of the joint distribution. The rank of the constructed tensor is equal to the number of mixture components. We present an algorithm to recover the components by partitioning the data p...
computer science
2,397
Sample complexity of learning Mahalanobis distance metrics
cs.LG
Metric learning seeks a transformation of the feature space that enhances prediction quality for the given task at hand. In this work we provide PAC-style sample complexity rates for supervised metric learning. We give matching lower- and upper-bounds showing that the sample complexity scales with the representation di...
computer science
2,398
Algorithmic Connections Between Active Learning and Stochastic Convex Optimization
cs.LG
Interesting theoretical associations have been established by recent papers between the fields of active learning and stochastic convex optimization due to the common role of feedback in sequential querying mechanisms. In this paper, we continue this thread in two parts by exploiting these relations for the first time ...
computer science
2,399
An Experimental Comparison of Hybrid Algorithms for Bayesian Network Structure Learning
stat.ML
We present a novel hybrid algorithm for Bayesian network structure learning, called Hybrid HPC (H2PC). It first reconstructs the skeleton of a Bayesian network and then performs a Bayesian-scoring greedy hill-climbing search to orient the edges. It is based on a subroutine called HPC, that combines ideas from increment...
computer science