Classification n Grouping of like objects (entities, documents, products) n Aboutness n Collocation – Taxonomy, Ontology, Schema, Systematics, Nomenclature, ….
Classification History n Aristotle – Category • (Greek kategoría, accusation, attribution). – E. g. , Blood-bearing animals • Four-footed animals, live birth • Birds • Egg-laying 4 -footed animals (reptiles + amphibians) • Whales and their allies • Fishes n Carl Von Linne, (Linnaeus)
Linnaean taxonomy
Classification History n Aristotle - Classical Theory of Categories – things are categorized together based on what they have in common (properties) – Clear boundaries, hierarchy mirroring the actual world – Unchallenged until mid-19 th c.
Cracks in Classical Theory n Research in logic and psychology – Wittgenstein, 1953, family resemblances – Austin, 1961, studied words – Zadeh, 1965, fuzzy set theory – Lonsbury, 1965, family kinship – Rosch, 1973 -early 1980’s, prototype theory – Ad hoc categories
Human Categorization n Anytime we see something as a kind of thing, for example, a tree, we are categorizing. Whenever we reason about kinds of things – chairs, nations, illnesses, emotions, any kind of things at all – we are employing categories. Lakoff, George (1987). Women, Fire, and Dangerous Things. Chicago, IL: University of Chicago Press.
Langridge n Purpose – Facilitates everyday life – Choice of classification is always related to purpose n Natural vs. Artificial classification – What is the difference? – Situational classification
Langridge n Same object may be classified in many ways n No absolute classification n Classifications are made not discovered
Langridge n Classification of phenomena not limited to sciences – Knowledge classification – Knowledge organization • Is there a boundary? n Bibliographic classification – Knowledge after it has been embodied – theme
Classification n Used a multitude of places and environments: – Supermarkets – Knowledge bases of expert systems – Institutional archives & repositories – Digital & physical libraries (collocation and stack arrangement) – Web pages -- design of menus for interactive searching – Etc…
Classification Advantages n Context, grouping n Overview of the scope of a service n Browsing, serendipity – Broadening and narrowing a search (hierarchy subject tree) – Browsing a directory-type structure is user friendly – Look for related items not previously identified as relevant - serendipity n Partitioning / Segmenting (facets)
Classification Advantages continued n Multilingual access – Same semantics across databases n Interoperability on agreed classification schemes n Permanence n Known by users n Available in machine readable form
Classification Criticisms n Logical division splits related materials n Illogical division of classes n Difficulties and delay in adding new topics
Bio. Medical Classification systems 1. 2. 3. 4. 5. 6. 7. UMLS, Mes. H SNOMED CT LOINC ICD GO OBO Foundry Nation Center for Biomedical Ontology
Structure of Classification Schemes n Structure – Enumerative (a list) – Faceted (parts) – Hierarchical (structured from general to specific)
Enumerative n History – Art history – Medieval history – Roman history – Scientific history – http: //www. yahoo. com – http: //www. froogle. com
Faceted n Faceted classification works on an “analytico-synthetic principle” – System: Fundamental concepts are analyzed and grouped together into facets – Concepts are combined or “synthesized” as necessary to form more complex subjects
Facets n AAT (Art and Architecture Thesaurus) – Physical attributes (size, shape, texture) – Styles and periods – Agents – Materials – Objects (chair, painting) – http: //www. getty. edu/research/conducting_researc h/vocabularies/aat/about. html • Ornate style n On-line Shopping (Best Buy)
Hierarchical n Super-ordinate and sub-ordinate n Genus/species n Class/member More flexible application in classification systems than in terminological tools (thesauri, ontologies, etc. ) n Example -- UMLS/Me. SH
Hierarchical example w/BEER Ale Bitter Brown Ale India Pale Ale Mild Pale Ale Lager Pilsner Porter Stout Sweet Stout Dry Stout Imperial Stout
Me. SH Tree Browser n Explore Mesh (use brain cancer) n Mesh Tree Browser
What does the future hold n Hint… n Databases evolved from hierarchical to network, to relational. n Maybe Classification is evolving from hierarchical to faceted (somewhat analogous to relational).
Скачать презентацию Classification n Grouping of like objects entities documents
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