Models and Estimation Algorithms for Nonparametric Finite Mixtures with Conditionally Independent Multivariate Component Densities

Models and Estimation Algorithms for Nonparametric Finite Mixtures with Conditionally Independent Multivariate Component Densities PDF Author: Vy-Thuy-Lynh Hoang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Recently several authors have proposed models and estimation algorithms for finite nonparametric multivariate mixtures, whose identifiability is typically not obvious. Among the considered models, the assumption of independent coordinates conditional on the subpopulation from which each observation is drawn is subject of an increasing attention, in view of the theoretical and practical developments it allows, particularly with multiplicity of variables coming into play in the modern statistical framework. In this work we first consider a more general model assuming independence, conditional on the component, of multivariate blocks of coordinates instead of univariate coordinates, allowing for any dependence structure within these blocks. Consequently, the density functions of these blocks are completely multivariate and nonparametric. We present identifiability arguments and introduce for estimation in this model two methodological algorithms whose computational procedures resemble a true EM algorithm but include an additional density estimation step: a fast algorithm showing empirical efficiency without theoretical justification, and a smoothed algorithm possessing a monotony property as any EM algorithm does, but more computationally demanding. We also discuss computationally efficient methods for estimation and derive some strategies. Next, we consider a multivariate extension of the mixture models used in the framework of multiple hypothesis testings, allowing for a new multivariate version of the False Discovery Rate control. We propose a constrained version of our previous algorithm, specifically designed for this model. The behavior of the EM-type algorithms we propose is studied numerically through several Monte Carlo experiments and high dimensional real data, and compared with existing methods in the literature. Finally, the codes of our new algorithms are progressively implemented as new functions in the publicly-available package mixtools for the R statistical software.

Models and Estimation Algorithms for Nonparametric Finite Mixtures with Conditionally Independent Multivariate Component Densities

Models and Estimation Algorithms for Nonparametric Finite Mixtures with Conditionally Independent Multivariate Component Densities PDF Author: Vy-Thuy-Lynh Hoang
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Book Description
Recently several authors have proposed models and estimation algorithms for finite nonparametric multivariate mixtures, whose identifiability is typically not obvious. Among the considered models, the assumption of independent coordinates conditional on the subpopulation from which each observation is drawn is subject of an increasing attention, in view of the theoretical and practical developments it allows, particularly with multiplicity of variables coming into play in the modern statistical framework. In this work we first consider a more general model assuming independence, conditional on the component, of multivariate blocks of coordinates instead of univariate coordinates, allowing for any dependence structure within these blocks. Consequently, the density functions of these blocks are completely multivariate and nonparametric. We present identifiability arguments and introduce for estimation in this model two methodological algorithms whose computational procedures resemble a true EM algorithm but include an additional density estimation step: a fast algorithm showing empirical efficiency without theoretical justification, and a smoothed algorithm possessing a monotony property as any EM algorithm does, but more computationally demanding. We also discuss computationally efficient methods for estimation and derive some strategies. Next, we consider a multivariate extension of the mixture models used in the framework of multiple hypothesis testings, allowing for a new multivariate version of the False Discovery Rate control. We propose a constrained version of our previous algorithm, specifically designed for this model. The behavior of the EM-type algorithms we propose is studied numerically through several Monte Carlo experiments and high dimensional real data, and compared with existing methods in the literature. Finally, the codes of our new algorithms are progressively implemented as new functions in the publicly-available package mixtools for the R statistical software.

Finite Mixture Models

Finite Mixture Models PDF Author: Geoffrey McLachlan
Publisher: John Wiley & Sons
ISBN: 047165406X
Category : Mathematics
Languages : en
Pages : 419

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Book Description
An up-to-date, comprehensive account of major issues in finitemixture modeling This volume provides an up-to-date account of the theory andapplications of modeling via finite mixture distributions. With anemphasis on the applications of mixture models in both mainstreamanalysis and other areas such as unsupervised pattern recognition,speech recognition, and medical imaging, the book describes theformulations of the finite mixture approach, details itsmethodology, discusses aspects of its implementation, andillustrates its application in many common statisticalcontexts. Major issues discussed in this book include identifiabilityproblems, actual fitting of finite mixtures through use of the EMalgorithm, properties of the maximum likelihood estimators soobtained, assessment of the number of components to be used in themixture, and the applicability of asymptotic theory in providing abasis for the solutions to some of these problems. The author alsoconsiders how the EM algorithm can be scaled to handle the fittingof mixture models to very large databases, as in data miningapplications. This comprehensive, practical guide: * Provides more than 800 references-40% published since 1995 * Includes an appendix listing available mixture software * Links statistical literature with machine learning and patternrecognition literature * Contains more than 100 helpful graphs, charts, and tables Finite Mixture Models is an important resource for both applied andtheoretical statisticians as well as for researchers in the manyareas in which finite mixture models can be used to analyze data.

Non-Parametric Finite Multivariate Mixture Models with Applications

Non-Parametric Finite Multivariate Mixture Models with Applications PDF Author: XIAOTIAN ZHU
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
This research set out to investigate and build upon the foundation for the nonparametric estimation of finite multivariate mixture models given the conditional independence assumption, set forth in a series of studies over the last decade. We proposed a novel formulation of the objective function in terms of penalized smoothed Kullback-Leibler divergence under a reduced parameter space. A special optimization landscape and scheme was discovered in working out the majorizationminimization method for the estimation problem which leads to a closed form of the nonlinearly smoothed majorization-minimization (NSMM) algorithm. We established a sharpened monotonicity property that precisely measures the distance between successive iterates of the algorithm and proved the existence of a solution to the main optimization problem for the first time in literature. The estimation theory for this basic model together with the special optimization scheme can be adapted to the investigation of an important extension of the model that incorporates component-wise independent component analysis (ICA). The NSMMICA algorithm has been developed and a discretized version of it, which interweaves NSMM and weighted FastICA has been implemented in the R package icamix as a model-based clustering tool. We demonstrated the use of the newly developed methods/algorithms by applications in image analysis and unsupervised learning.

Mixtures

Mixtures PDF Author: Kerrie L. Mengersen
Publisher: John Wiley & Sons
ISBN: 1119998441
Category : Mathematics
Languages : en
Pages : 352

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Book Description
This book uses the EM (expectation maximization) algorithm to simultaneously estimate the missing data and unknown parameter(s) associated with a data set. The parameters describe the component distributions of the mixture; the distributions may be continuous or discrete. The editors provide a complete account of the applications, mathematical structure and statistical analysis of finite mixture distributions along with MCMC computational methods, together with a range of detailed discussions covering the applications of the methods and features chapters from the leading experts on the subject. The applications are drawn from scientific discipline, including biostatistics, computer science, ecology and finance. This area of statistics is important to a range of disciplines, and its methodology attracts interest from researchers in the fields in which it can be applied.

Nonparametric Statistics And Mixture Models: A Festschrift In Honor Of Thomas P Hettmansperger

Nonparametric Statistics And Mixture Models: A Festschrift In Honor Of Thomas P Hettmansperger PDF Author: David Hunter
Publisher: World Scientific
ISBN: 9814460966
Category : Mathematics
Languages : en
Pages : 370

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Book Description
This festschrift includes papers authored by many collaborators, colleagues, and students of Professor Thomas P Hettmansperger, who worked in research in nonparametric statistics, rank statistics, robustness, and mixture models during a career that spanned nearly 40 years. It is a broad sample of peer-reviewed, cutting-edge research related to nonparametrics and mixture models.

Bayesian Nonparametrics

Bayesian Nonparametrics PDF Author: J.K. Ghosh
Publisher: Springer Science & Business Media
ISBN: 0387226540
Category : Mathematics
Languages : en
Pages : 311

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Book Description
This book is the first systematic treatment of Bayesian nonparametric methods and the theory behind them. It will also appeal to statisticians in general. The book is primarily aimed at graduate students and can be used as the text for a graduate course in Bayesian non-parametrics.

Estimation of Finite Mixture Models

Estimation of Finite Mixture Models PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
A recorded signal frequently results from the mixture of many signals from several classifiable sources. Knowledge of the contribution of the underlying sources to the recorded signal is valuable in several applications, such as remote sensing. Such mixtures may be analyzed using finite mixture models. Historically, finite mixture models decompose a density as the sum of a finite number of component densities. Current methods for estimating the contribution of each component assume a parametric form for the mixture components. Furthermore, these methods assume a collection of samples from the mixture are observed rather than an aggregate representation of the samples, such as a histogram. This work introduces a method to address the many practical cases where parametric mixture models are insufficient to describe the mixture components. The observed mixture is assumed to occur in an aggregate representation of samples. Thus, the mixture components are represented as finite-length signals or vectors. The proposed method incorporates the first and second order statistics of the mixture components obtained from previously collected samples of the mixture components. The new method is based on the set theoretic method of successive projections onto convex sets (POCS). The set theoretic approach defines a set of feasible solutions as the intersection of sets consistent with the prior knowledge of a desirable solution. POCS is an iterative procedure used to find a point in the set of feasible solutions. This work considers several sets describing the finite mixture model, including a new model set generalizing a set based on the error-in-variables model. To illustrate the viability of the new method, comparisons are made with the expectation-maximization (EM) algorithm for mixtures with parametric components. Simulations of mixture with nonparametric components emphasize the advantages of the new method, since no other methods address mixtures with nonparametric component.

Nonparametric Statistics and Mixture Models

Nonparametric Statistics and Mixture Models PDF Author: David R. Hunter
Publisher: World Scientific
ISBN: 9814340553
Category : Mathematics
Languages : en
Pages : 370

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Book Description
This festschrift includes papers authored by many collaborators, colleagues, and students of Professor Thomas P Hettmansperger, who worked in research in nonparametric statistics, rank statistics, robustness, and mixture models during a career that spanned nearly 40 years. It is a broad sample of peer-reviewed, cutting-edge research related to nonparametrics and mixture models.

Mixture Models and Applications

Mixture Models and Applications PDF Author: Nizar Bouguila
Publisher: Springer
ISBN: 3030238768
Category : Technology & Engineering
Languages : en
Pages : 355

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Book Description
This book focuses on recent advances, approaches, theories and applications related to mixture models. In particular, it presents recent unsupervised and semi-supervised frameworks that consider mixture models as their main tool. The chapters considers mixture models involving several interesting and challenging problems such as parameters estimation, model selection, feature selection, etc. The goal of this book is to summarize the recent advances and modern approaches related to these problems. Each contributor presents novel research, a practical study, or novel applications based on mixture models, or a survey of the literature. Reports advances on classic problems in mixture modeling such as parameter estimation, model selection, and feature selection; Present theoretical and practical developments in mixture-based modeling and their importance in different applications; Discusses perspectives and challenging future works related to mixture modeling.

Handbook of Mixture Analysis

Handbook of Mixture Analysis PDF Author: Sylvia Fruhwirth-Schnatter
Publisher: CRC Press
ISBN: 0429508867
Category : Computers
Languages : en
Pages : 388

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Book Description
Mixture models have been around for over 150 years, and they are found in many branches of statistical modelling, as a versatile and multifaceted tool. They can be applied to a wide range of data: univariate or multivariate, continuous or categorical, cross-sectional, time series, networks, and much more. Mixture analysis is a very active research topic in statistics and machine learning, with new developments in methodology and applications taking place all the time. The Handbook of Mixture Analysis is a very timely publication, presenting a broad overview of the methods and applications of this important field of research. It covers a wide array of topics, including the EM algorithm, Bayesian mixture models, model-based clustering, high-dimensional data, hidden Markov models, and applications in finance, genomics, and astronomy. Features: Provides a comprehensive overview of the methods and applications of mixture modelling and analysis Divided into three parts: Foundations and Methods; Mixture Modelling and Extensions; and Selected Applications Contains many worked examples using real data, together with computational implementation, to illustrate the methods described Includes contributions from the leading researchers in the field The Handbook of Mixture Analysis is targeted at graduate students and young researchers new to the field. It will also be an important reference for anyone working in this field, whether they are developing new methodology, or applying the models to real scientific problems.