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Library | Materyal Türü | Barkod | Yer Numarası | Durum |
|---|---|---|---|---|
Searching... Pamukkale Merkez Kütüphanesi | Kitap | 0017542 | QA76.76.E95P755 1999 | Searching... Unknown |
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Özet
Özet
WINNER OF THE 2001 DEGROOT PRIZE!
Probabilistic expert systems are graphical networks that support the modelling of uncertainty and decisions in large complex domains, while retaining ease of calculation. Building on original research by the authors over a number of years, this book gives a thorough and rigorous mathematical treatment of the underlying ideas, structures, and algorithms, emphasizing those cases in which exact answers are obtainable. It covers both the updating of probabilistic uncertainty in the light of new evidence, and statistical inference, about unknown probabilities or unknown model structure, in the light of new data. The careful attention to detail will make this work an important reference source for all those involved in the theory and applications of probabilistic expert systems.
This book was awarded the first DeGroot Prize by the International Society for Bayesian Analysis for a book making an important, timely, thorough, and notably original contribution to the statistics literature.
Author Notes
Robert G. Cowell is Research Fellow and Computer Manager in the Department of Actuarial Science and Statistics of City University, London.
A. Philip Dawid is Professor of Statistics at University College London.
Steffen L. Lauritzen is Professor of Mathematics and Statistics at the University of Aalborg.
David J. Spiegelhalter is a Senior Scientist at the MRC Biostatistics Unit in the Cambridge University Institute of Public Health.
Table of Contents
| Preface | p. v |
| 1 Introduction | p. 1 |
| 1.1 What is this book about? | p. 1 |
| 1.2 What is in this book? | p. 2 |
| 1.3 What is not in this book? | p. 3 |
| 1.4 How should this be book be used? | p. 4 |
| 2 Logic, Uncertainty, and Probability | p. 5 |
| 2.1 What is an expert system? | p. 5 |
| 2.2 Diagnostic decision trees | p. 6 |
| 2.3 Production systems | p. 7 |
| 2.4 Coping with uncertainty | p. 8 |
| 2.5 The naive probabilistic approach | p. 10 |
| 2.6 Interpretations of probability | p. 11 |
| 2.7 Axioms | p. 13 |
| 2.8 Bayes' theorem | p. 14 |
| 2.9 Bayesian reasoning in expert systems | p. 17 |
| 2.10 A broader context for probabilistic expert systems | p. 21 |
| 3 Building and Using Probabilistic Networks | p. 25 |
| 3.1 Graphical modelling of the domain | p. 26 |
| 3.1.1 Qualitative modelling | p. 27 |
| 3.1.2 Probabilistic modelling | p. 28 |
| 3.1.3 Quantitative modelling | p. 29 |
| 3.1.4 Further background to the elicitation process | p. 29 |
| 3.2 From specification to inference engine | p. 31 |
| 3.2.1 Moralization | p. 31 |
| 3.2.2 From moral graph to junction tree | p. 33 |
| 3.3 The inference process | p. 34 |
| 3.3.1 The clique-marginal representation | p. 36 |
| 3.3.2 Incorporation of evidence | p. 36 |
| 3.4 Bayesian networks as expert systems | p. 37 |
| 3.5 Background references and further reading | p. 40 |
| 3.5.1 Structuring the graph | p. 40 |
| 3.5.2 Specifying the probability distribution | p. 40 |
| 4 Graph Theory | p. 43 |
| 4.1 Basic concepts | p. 43 |
| 4.2 Chordal and decomposable graphs | p. 49 |
| 4.3 Junction trees | p. 52 |
| 4.4 From chain graph to junction tree | p. 55 |
| 4.4.1 Triangulation | p. 57 |
| 4.4.2 Elimination tree | p. 59 |
| 4.5 Background references and further reading | p. 61 |
| 5 Markov Properties on Graphs | p. 63 |
| 5.1 Conditional independence | p. 63 |
| 5.2 Markov fields over undirected graphs | p. 66 |
| 5.3 Markov properties on directed acyclic graphs | p. 70 |
| 5.4 Markov properties on chain graphs | p. 75 |
| 5.5 Current research directions | p. 79 |
| 5.5.1 Markov equivalence | p. 79 |
| 5.5.2 Other graphical representations | p. 80 |
| 5.6 Background references and further reading | p. 80 |
| 6 Discrete Networks | p. 83 |
| 6.1 An illustration of local computation | p. 84 |
| 6.2 Definitions | p. 85 |
| 6.2.1 Basic operations | p. 86 |
| 6.3 Local computation on the junction tree | p. 87 |
| 6.3.1 Graphical specification | p. 87 |
| 6.3.2 Numerical specification and initialization | p. 87 |
| 6.3.3 Charges | p. 88 |
| 6.3.4 Flow of information between adjacent cliques | p. 88 |
| 6.3.5 Active flows | p. 89 |
| 6.3.6 Reaching equilibrium | p. 90 |
| 6.3.7 Scheduling of flows | p. 92 |
| 6.3.8 Two-phase propagation | p. 92 |
| 6.3.9 Entering and propagating evidence | p. 93 |
| 6.3.10 A propagation example | p. 95 |
| 6.4 Generalized marginalization operations | p. 95 |
| 6.4.1 Maximization | p. 97 |
| 6.4.2 Degeneracy of the most probable configuration | p. 99 |
| 6.4.3 Simulation | p. 99 |
| 6.4.4 Finding the M most probable configurations | p. 101 |
| 6.4.5 Sampling without replacement | p. 103 |
| 6.4.6 Fast retraction | p. 104 |
| 6.4.7 Moments of functions | p. 106 |
| 6.5 Example: Ch-Asia | p. 109 |
| 6.5.1 Description | p. 109 |
| 6.5.2 Graphical specification | p. 109 |
| 6.5.3 Numerical specification | p. 109 |
| 6.5.4 Initialization | p. 112 |
| 6.5.5 Propagation without evidence | p. 114 |
| 6.5.6 Propagation with evidence | p. 114 |
| 6.5.7 Max-propagation | p. 119 |
| 6.6 Dealing with large cliques | p. 120 |
| 6.6.1 Truncating small numbers | p. 121 |
| 6.6.2 Splitting cliques | p. 122 |
| 6.7 Current research directions and further reading | p. 123 |
| 7 Gaussian and Mixed Discrete-Gaussian Networks | p. 125 |
| 7.1 CG distributions | p. 126 |
| 7.2 Basic operations on CG potentials | p. 127 |
| 7.3 Marked graphs and their junction trees | p. 131 |
| 7.3.1 Decomposition of marked graphs | p. 131 |
| 7.3.2 Junction trees with strong roots | p. 133 |
| 7.4 Model specification | p. 135 |
| 7.5 Operating in the junction tree | p. 137 |
| 7.5.1 Initializing the junction tree | p. 138 |
| 7.5.2 Charges | p. 138 |
| 7.5.3 Entering evidence | p. 139 |
| 7.5.4 Flow of information between adjacent cliques | p. 139 |
| 7.5.5 Two-phase propagation | p. 141 |
| 7.6 A simple Gaussian example | p. 143 |
| 7.7 Example: Waste | p. 144 |
| 7.7.1 Structural specification | p. 145 |
| 7.7.2 Numerical specification | p. 146 |
| 7.7.3 Strong triangulation | p. 147 |
| 7.7.4 Forming the junction tree | p. 148 |
| 7.7.5 Initializing the junction tree | p. 148 |
| 7.7.6 Entering evidence | p. 149 |
| 7.8 Complexity considerations | p. 150 |
| 7.9 Numerical instability problems | p. 151 |
| 7.9.1 Exact marginal densities | p. 152 |
| 7.10 Current research directions | p. 152 |
| 7.11 Background references and further reading | p. 153 |
| 8 Discrete Multistage Decision Networks | p. 155 |
| 8.1 The nature of multistage decision problems | p. 156 |
| 8.2 Solving the decision problem | p. 157 |
| 8.3 Decision potentials | p. 159 |
| 8.4 Network specification and solution | p. 163 |
| 8.4.1 Structural and numerical specification | p. 163 |
| 8.4.2 Causal consistency lemma | p. 165 |
| 8.4.3 Making the elimination tree | p. 166 |
| 8.4.4 Initializing the elimination tree | p. 167 |
| 8.4.5 Message passing in the elimination tree | p. 168 |
| 8.4.6 Proof of elimination tree solution | p. 169 |
| 8.5 Example: Oil Wildcatter | p. 172 |
| 8.5.1 Specification | p. 172 |
| 8.5.2 Making the elimination tree | p. 175 |
| 8.5.3 Initializing the elimination tree | p. 176 |
| 8.5.4 Collecting evidence | p. 177 |
| 8.6 Example: Dec-Asia | p. 177 |
| 8.7 Triangulation issues | p. 183 |
| 8.8 Asymmetric problems | p. 184 |
| 8.9 Background references and further reading | p. 187 |
| 9 Learning About Probabilities | p. 189 |
| 9.1 Statistical modelling and parameter learning | p. 189 |
| 9.2 Parametrizing a directed Markov model | p. 190 |
| 9.3 Maximum likelihood with complete data | p. 192 |
| 9.4 Bayesian updating with complete data | p. 193 |
| 9.4.1 Priors for DAG models | p. 193 |
| 9.4.2 Specifying priors: An example | p. 197 |
| 9.4.3 Updating priors with complete data: An example | p. 199 |
| 9.5 Incomplete data | p. 200 |
| 9.5.1 Sequential and batch methods | p. 201 |
| 9.6 Maximum likelihood with incomplete data | p. 202 |
| 9.6.1 The EM algorithm | p. 202 |
| 9.6.2 Penalized EM algorithm | p. 204 |
| 9.7 Bayesian updating with incomplete data | p. 204 |
| 9.7.1 Exact theory | p. 206 |
| 9.7.2 Retaining global independence | p. 207 |
| 9.7.3 Retaining local independence | p. 209 |
| 9.7.4 Reducing the mixtures | p. 211 |
| 9.7.5 Simulation results: full mixture reduction | p. 213 |
| 9.7.6 Simulation results: partial mixture reduction | p. 214 |
| 9.8 Using Gibbs sampling for learning | p. 216 |
| 9.9 Hyper Markov laws for undirected models | p. 221 |
| 9.10 Current research directions and further reading | p. 222 |
| 10 Checking Models Against Data | p. 225 |
| 10.1 Scoring rules | p. 226 |
| 10.1.1 Standardization | p. 227 |
| 10.2 Parent-child monitors | p. 229 |
| 10.2.1 Batch monitors | p. 232 |
| 10.2.2 Missing data | p. 233 |
| 10.3 Node monitors | p. 234 |
| 10.4 Global monitors | p. 235 |
| 10.4.1 Example: Child | p. 236 |
| 10.5 Simulation experiments | p. 238 |
| 10.6 Further reading | p. 241 |
| 11 Structural Learning | p. 243 |
| 11.1 Purposes of modelling | p. 244 |
| 11.2 Inference about models | p. 244 |
| 11.3 Criteria for comparing models | p. 245 |
| 11.3.1 Maximized likelihood | p. 246 |
| 11.3.2 Predictive assessment | p. 247 |
| 11.3.3 Marginal likelihood | p. 248 |
| 11.3.4 Model probabilities | p. 249 |
| 11.3.5 Model selection and model averaging | p. 250 |
| 11.4 Graphical models and conditional independence | p. 251 |
| 11.5 Classes of models | p. 253 |
| 11.5.1 Models containing only observed quantities | p. 253 |
| 11.5.2 Models with latent or hidden variables | p. 254 |
| 11.5.3 Missing data | p. 255 |
| 11.6 Handling multiple models | p. 256 |
| 11.6.1 Search strategies | p. 256 |
| 11.6.2 Probability specification | p. 258 |
| 11.6.3 Prior information on parameters | p. 260 |
| 11.6.4 Variable precision | p. 261 |
| Epilogue | p. 265 |
| A Conjugate Analysis for Discrete Data | p. 267 |
| A.1 Bernoulli process | p. 267 |
| A.2 Multinomial process | p. 269 |
| B Gibbs Sampling | p. 271 |
| B.1 Gibbs sampling | p. 271 |
| B.2 Sampling from the moral graph | p. 273 |
| B.3 General probability densities | p. 274 |
| B.4 Further reading | p. 275 |
| C Information and Software on the World Wide Web | p. 277 |
| C.1 Information about probabilistic networks | p. 277 |
| C.2 Software for probabilistic networks | p. 279 |
| C.3 Markov chain Monte Carlo methods | p. 280 |
| Bibliography | p. 281 |
| Author Index | p. 307 |
| Subject Index | p. 313 |
