Statistical Dependence in Markov Random Field Models

Thumbnail Image
Date
2007-04-01
Authors
Kaiser, Mark
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
Authors
Research Projects
Organizational Units
Organizational Unit
Statistics
As leaders in statistical research, collaboration, and education, the Department of Statistics at Iowa State University offers students an education like no other. We are committed to our mission of developing and applying statistical methods, and proud of our award-winning students and faculty.
Journal Issue
Is Version Of
Versions
Series
Department
Statistics
Abstract

Statistical models based on Markov random fields present a flexible means for modeling statistical dependencies in a variety of situations including, but not limited to, spatial problems with observations on a lattice. The simplest of such models, sometimes called ``auto-models'' are formulated from sets of conditional one-parameter exponential family densities or mass functions. Despite the attractive nature of these models for dealing with complex dependence structures, their application has been hindered by a lack of interpretability relative to the manner in which dependencies are represented. In particular, while the parameters that embody dependence are nicely isolated in these models, the meaning of numerical values of those parameters as representing dependence of varying strengths has been poorly understood. In addition, it is known that dependence parameters that are ``too large'' lead to un-interpretable or even degenerate behavior in data sets simulated from models having such parameters. The objectives of this article are to identify a concept of dependence that is generally applicable to Markov random field models based on one-parameter exponential families, and to demonstrate the relation between a quantification of this concept of dependence and the dependence parameters in models. It is then possible to both quantify the strength of statistical dependencies represented by particular numerical values of dependence parameters, and delineate ranges of those parameters that lead to separable interpretations of large-scale model components as marginal mean structure and small-scale components as additional statistical dependence.

Comments

This preprint was published as Mark Kaiser, "Markov Random Field Models", Encyclopedia of Environmetrics (2006): doi: 10.1002/9780470057339.vam005

Description
Keywords
Citation
DOI
Subject Categories
Copyright
Collections