\contentsline {chapter}{List of Tables}{vii}
\contentsline {chapter}{List of Figures}{ix}
\contentsline {chapter}{Abstract}{x}
\contentsline {chapter}{Acknowledgments}{xii}
\contentsline {chapter}{\numberline {1}Introduction}{1}
\contentsline {section}{\numberline {1.1}Aims and Significance of Research}{1}
\contentsline {subsection}{\numberline {1.1.1}Statement of Reasearch Problem}{2}
\contentsline {section}{\numberline {1.2}Research Methods and Plans}{3}
\contentsline {subsection}{\numberline {1.2.1}Scope}{3}
\contentsline {subsection}{\numberline {1.2.2}Limitations}{3}
\contentsline {section}{\numberline {1.3}Thesis Outline}{4}
\contentsline {chapter}{\numberline {2}Inference}{5}
\contentsline {section}{\numberline {2.1}Abductive Inference}{6}
\contentsline {chapter}{\numberline {3}Testing}{9}
\contentsline {section}{\numberline {3.1}Verification}{9}
\contentsline {subsection}{\numberline {3.1.1}Anomalies}{10}
\contentsline {subsection}{\numberline {3.1.2}Verification Tools}{10}
\contentsline {subsubsection}{Rule Checker Program}{11}
\contentsline {subsubsection}{The KB-Reducer Algorithm}{12}
\contentsline {subsubsection}{The EVA system}{13}
\contentsline {subsection}{\numberline {3.1.3}Discussion}{14}
\contentsline {subsection}{\numberline {3.1.4}HT4 and Verification}{14}
\contentsline {section}{\numberline {3.2}Validation}{15}
\contentsline {subsubsection}{Validation Facility}{15}
\contentsline {subsubsection}{Refinement Facility}{15}
\contentsline {subsubsection}{Test Case Generation Facility}{15}
\contentsline {subsection}{\numberline {3.2.1}Dynamic Validation}{16}
\contentsline {subsubsection}{Empirical Approach}{17}
\contentsline {subsubsection}{Logical Approach}{17}
\contentsline {subsubsection}{Operational Approach}{19}
\contentsline {subsubsection}{Machine Learning Approach}{20}
\contentsline {subsection}{\numberline {3.2.2}Static Validation}{20}
\contentsline {subsubsection}{Random Test Case Generation}{20}
\contentsline {subsubsection}{Structured-based Test Case Generation}{21}
\contentsline {subsubsection}{Functional-based Test Case Generation}{21}
\contentsline {subsection}{\numberline {3.2.3}Validation Systems}{21}
\contentsline {subsubsection}{The Generic Testing Method}{21}
\contentsline {subsubsection}{EVA Test Case Generator Tools}{22}
\contentsline {subsubsection}{ONCOCIN ScriptGen}{23}
\contentsline {subsection}{\numberline {3.2.4}HT4 and Validation}{24}
\contentsline {subsubsection}{HT4 Results}{24}
\contentsline {chapter}{\numberline {4}Overview of HT4}{26}
\contentsline {section}{\numberline {4.1}Describing HT4}{26}
\contentsline {section}{\numberline {4.2}An example using HT4}{28}
\contentsline {section}{\numberline {4.3}HT4 and Abduction}{31}
\contentsline {section}{\numberline {4.4}Applications of HT4}{32}
\contentsline {subsection}{\numberline {4.4.1}Model-Based Diagnosis}{33}
\contentsline {subsection}{\numberline {4.4.2}Prediction}{34}
\contentsline {subsection}{\numberline {4.4.3}Explanation}{34}
\contentsline {subsection}{\numberline {4.4.4}Classification}{35}
\contentsline {subsection}{\numberline {4.4.5}Planning}{35}
\contentsline {subsection}{\numberline {4.4.6}Monitoring}{36}
\contentsline {subsection}{\numberline {4.4.7}Validation}{37}
\contentsline {section}{\numberline {4.5}Generality in Non-Abductive Domains}{37}
\contentsline {subsection}{\numberline {4.5.1}Deduction}{37}
\contentsline {subsection}{\numberline {4.5.2}KBS Verification}{37}
\contentsline {subsubsection}{Redundancy}{38}
\contentsline {subsubsection}{Ambivalence}{39}
\contentsline {subsubsection}{Circularity}{39}
\contentsline {subsubsection}{Deficiency}{39}
\contentsline {subsection}{\numberline {4.5.3}Expert Critiquing Systems}{39}
\contentsline {section}{\numberline {4.6}Practicality of HT4}{41}
\contentsline {section}{\numberline {4.7}System Outline}{43}
\contentsline {subsection}{\numberline {4.7.1}System Files}{43}
\contentsline {subsection}{\numberline {4.7.2}The Dependency Network}{45}
\contentsline {subsection}{\numberline {4.7.3}The Data and Network Parser}{49}
\contentsline {section}{\numberline {4.8}The Data Compiler}{51}
\contentsline {chapter}{\numberline {5}The HT4 Algorithm}{56}
\contentsline {section}{\numberline {5.1}Introduction}{56}
\contentsline {section}{\numberline {5.2}Pseudo-Code}{56}
\contentsline {subsection}{\numberline {5.2.1}Models as Data Structures}{56}
\contentsline {subsection}{\numberline {5.2.2}Models as Graphs}{58}
\contentsline {subsection}{\numberline {5.2.3}Behaviours}{59}
\contentsline {subsection}{\numberline {5.2.4}Proofs}{61}
\contentsline {subsection}{\numberline {5.2.5}Worlds}{61}
\contentsline {subsection}{\numberline {5.2.6}Bitstrings}{62}
\contentsline {subsection}{\numberline {5.2.7}The HT4 Algorithm}{63}
\contentsline {subsubsection}{Overview}{63}
\contentsline {subsubsection}{Pseudo-Code}{64}
\contentsline {section}{\numberline {5.3}Best Assessment Operators}{81}
\contentsline {section}{\numberline {5.4}Differences in Pseudo-Code}{83}
\contentsline {chapter}{\numberline {6}The Smythe '89 study}{86}
\contentsline {chapter}{\numberline {7}Optimisations}{89}
\contentsline {section}{\numberline {7.1}Program Optimizations}{90}
\contentsline {subsection}{\numberline {7.1.1}Code Optimization}{90}
\contentsline {subsection}{\numberline {7.1.2}Memory Usage}{90}
\contentsline {section}{\numberline {7.2}Algorithmic Optimisations}{91}
\contentsline {subsection}{\numberline {7.2.1}Transitive Closure}{91}
\contentsline {subsubsection}{Description of Transitive Closure}{91}
\contentsline {subsubsection}{Results of Transitive Closure}{95}
\contentsline {subsection}{\numberline {7.2.2}Single World Assumption}{95}
\contentsline {subsubsection}{Description of Single World Assumption}{96}
\contentsline {subsubsection}{Results of Single World Assumption}{102}
\contentsline {subsubsection}{Results of Randomisation Study}{103}
\contentsline {section}{\numberline {7.3}Refining the Specifications}{103}
\contentsline {subsection}{\numberline {7.3.1}Description of Refining the Specifications}{104}
\contentsline {subsection}{\numberline {7.3.2}Results of Refining the Specifications}{105}
\contentsline {section}{\numberline {7.4}Discussion of Results}{105}
\contentsline {chapter}{\numberline {8}Conclusion}{107}
\contentsline {section}{\numberline {8.1}Future Work}{108}
\contentsline {chapter}{Appendix\ A\ Rule-Base Expert Systems}{110}
\contentsline {section}{\numberline {A.1}Definintions and Assumptions}{110}