semantic network complexity and metathesaurus maintenance stuart nelson, md “dr. ad hoc”
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Semantic Network ComplexitySemantic Network ComplexityAndAnd
Metathesaurus Maintenance Metathesaurus Maintenance
Stuart Nelson, MDStuart Nelson, MD
““Dr. Ad Hoc”Dr. Ad Hoc”
Role of Semantic NetworkRole of Semantic Network
Categorize the Concepts of the Categorize the Concepts of the MetathesaurusMetathesaurus
Model RealityModel Reality Model the ContentsModel the Contents
Semantic Network ProblemsSemantic Network Problems
Structural ConsiderationsStructural Considerations Limited UseLimited Use Poor Type AssignmentsPoor Type Assignments
Problematic AssignmentsProblematic Assignments
Inconsistent AssignmentsInconsistent Assignments ““Wrong” AssignmentsWrong” Assignments Strange Type Co-OccurrencesStrange Type Co-Occurrences
Why Do These Things Why Do These Things Happen”Happen”
Stupid Editors?Stupid Editors? Poor Selection of Types?Poor Selection of Types? Inherent Complexity?Inherent Complexity? Poor ManagementPoor Management
Where Does Complexity Arise, Where Does Complexity Arise, Or Why Is This So Hard?Or Why Is This So Hard?
Formalization GapFormalization Gap Duality of Central NotionsDuality of Central Notions Boundary PhenomenonBoundary Phenomenon Nelson’s LemmaNelson’s Lemma
Formalization GapFormalization Gap
Natural Language UnderstandingNatural Language UnderstandingPattern RecognitionPattern Recognition
Recall and Reliable MemoryRecall and Reliable MemoryFormal ReasoningFormal Reasoning
A Different AspectA Different Aspect
Humans Have Difficulty With Formal Humans Have Difficulty With Formal NotionsNotions
Formal DefinitionsFormal Definitions• A set of ordered pairsA set of ordered pairs• The set of first coordinates of the The set of first coordinates of the
ordered pairsordered pairs
Duality of Central Notions Duality of Central Notions
Cancer – Process or Object?Cancer – Process or Object? Gene – Locus or Sequence?Gene – Locus or Sequence? Finding - Event or Relationship?Finding - Event or Relationship? Waves and ParticlesWaves and Particles
Boundary Phenomenon Boundary Phenomenon
Definitional CharacteristicsDefinitional Characteristics Necessary and Sufficient AttributesNecessary and Sufficient Attributes
Nelson’s LemmaNelson’s Lemma
Greater Number of BoundariesGreater Number of Boundaries
LEADS TOLEADS TO
Greater Number of Borderline CasesGreater Number of Borderline Cases Overlapping “Extents”Overlapping “Extents”
Process of Semantic Type Process of Semantic Type AssignmentAssignment
Default Assignment from SourceDefault Assignment from Source Some Sources (MeSH) have STYsSome Sources (MeSH) have STYs Human Review of Concept StatusHuman Review of Concept Status Human Review of Semantic TypesHuman Review of Semantic Types
Practical ConsiderationsPractical Considerations
Achieving ConsistencyAchieving Consistency Managing ChangesManaging Changes Distribution of STY AssignmentsDistribution of STY Assignments Understanding Source MeaningsUnderstanding Source Meanings URU CriteriaURU Criteria
Achieving ConsistencyAchieving Consistency
See Nelson’s LemmaSee Nelson’s Lemma Internal (Self) ConsistencyInternal (Self) Consistency Editorial VariabilityEditorial Variability Inconsistent RulesInconsistent Rules
• Use ParentUse Parent• Use Several ChildrenUse Several Children
Managing ChangesManaging Changes
How Many Seconds per Change?How Many Seconds per Change? How Many Records to Edit?How Many Records to Edit? What Can Be Done Algorithmically?What Can Be Done Algorithmically? Resources AvailableResources Available
Distribution of AssignmentsDistribution of Assignments
Overlapping MeaningsOverlapping Meanings Facet-Based TypingFacet-Based Typing Inconsistent RulesInconsistent Rules
Understanding Source MeaningsUnderstanding Source Meanings
Definitions RareDefinitions Rare ““Contextual Understanding”Contextual Understanding”
• HierarchiesHierarchies Most Vocabularies A Set of Most Vocabularies A Set of
Engineering CompromisesEngineering Compromises
Prime Directive Prime Directive
Respect the Meaning in the SourceRespect the Meaning in the Source Names Lack Face ValidityNames Lack Face Validity Reification of Relationships Reification of Relationships
RespectRespect
Reality - Names and Rules Only Reality - Names and Rules Only Reflect Our UnderstandingReflect Our Understanding
Sources - Reflect The View of The Sources - Reflect The View of The SourceSource
URU Criteria For TypesURU Criteria For Types
UnderstandableUnderstandable ReproducibleReproducible UsableUsable
ChallengesChallenges
AnalysisAnalysis• Useful algorithmsUseful algorithms• Time InvolvedTime Involved• Assessing BenefitAssessing Benefit
TrainingTraining• Establishing Business RulesEstablishing Business Rules• Testing ConsistencyTesting Consistency