ontology
In plain wordsA carefully defined vocabulary for a subject such as medicine, spelling out each kind of thing, how kinds nest inside one another, and which connections between them are allowed.
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Knowledge representation
A machine-readable model of a domain that fixes its vocabulary of concepts and states how they relate, typically comprising a class hierarchy (taxonomy), properties and relations with their permitted arguments, and logical axioms constraining how they combine — for example, that every enzyme is a protein, or that 'part of' is transitive. Ontologies give separately built systems a shared vocabulary, enable automated consistency checking and classification, and underpin the semantic websemantic web, n.: An effort to label data on the web in a standard, precise way so that programs, not only human readers, can tell what it means and connect facts drawn from many different sites., where they are commonly written in OWLWeb Ontology Language, prop. n.: A web standard language for writing ontologies — precise definitions of categories and their relationships — so that software can check them for contradictions and infer new facts., which is based on description logicsdescription logic, n.: A family of precise logical languages for defining categories and how they relate, such as 'a parent is a person with at least one child', designed so that a computer's reasoning about them always finishes.. Upper (foundational) ontologies such as BFO and DOLCE define very general categories — object, process, quality — for domain ontologies to specialize; widely used domain ontologies include the Gene Ontology and SNOMED CT.
We aligned both hospitals' records to a shared ontology before merging them.
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Philosophy
The branch of metaphysics that studies what exists and the most general categories of being. The AI sense borrows the word for an engineered, usually domain-specific inventory of categories, and the two are linked mainly by name.
Origin
The philosophical term dates from the early 17th century (Latin ontologia). Its engineering sense emerged in AI knowledge-sharing projects around 1990; Tom Gruber's 1993 definition of an ontology as 'an explicit specification of a conceptualization' became the standard reference.
Usage note
Usage ranges from a simple taxonomy or controlled vocabulary to a richly axiomatized logical theory. Not to be confused with a knowledge graphknowledge graph, n.: A huge web of facts stored as connections between things — 'Paris is the capital of France', 'Marie Curie won a Nobel Prize' — that computers can search, combine and reason over., which mainly records facts about individual entities; the two are often combined, the ontology supplying the schema and the graph the instances.
Related
- knowledge representationknowledge representation, n.: The study of how to record knowledge about objects, categories, rules and events in a precise format, so that a program can reason with it and reach conclusions nobody typed in.
- description logicdescription logic, n.: A family of precise logical languages for defining categories and how they relate, such as 'a parent is a person with at least one child', designed so that a computer's reasoning about them always finishes.
- semantic websemantic web, n.: An effort to label data on the web in a standard, precise way so that programs, not only human readers, can tell what it means and connect facts drawn from many different sites.
- Web Ontology LanguageWeb Ontology Language, prop. n.: A web standard language for writing ontologies — precise definitions of categories and their relationships — so that software can check them for contradictions and infer new facts.
- knowledge graphknowledge graph, n.: A huge web of facts stored as connections between things — 'Paris is the capital of France', 'Marie Curie won a Nobel Prize' — that computers can search, combine and reason over.
- CycCyc, prop. n.: An AI system built by specialists who spent decades typing in millions of everyday truths, such as 'people cannot be in two places at once', hoping to give computers common sense.
- knowledge graphknowledge graph, n.: A huge web of facts stored as connections between things — 'Paris is the capital of France', 'Marie Curie won a Nobel Prize' — that computers can search, combine and reason over.
Sources
- Gruber, T. R. (1993). A Translation Approach to Portable Ontology Specifications. Knowledge Acquisition 5(2), 199–220.
Mentioned in
CycCyc, prop. n.: An AI system built by specialists who spent decades typing in millions of everyday truths, such as 'people cannot be in two places at once', hoping to give computers common sense., frameframe, n.: In classic AI, a ready-made template for a familiar kind of thing or event, such as a kitchen or a job interview, with blanks to fill in and sensible default values., knowledge baseknowledge base, n.: A store of facts and rules that a program can reason with: like a database, but organized so that new conclusions can be worked out from it, not just looked up., knowledge graphknowledge graph, n.: A huge web of facts stored as connections between things — 'Paris is the capital of France', 'Marie Curie won a Nobel Prize' — that computers can search, combine and reason over., knowledge representationknowledge representation, n.: The study of how to record knowledge about objects, categories, rules and events in a precise format, so that a program can reason with it and reach conclusions nobody typed in., semantic networksemantic network, n.: A way of storing knowledge as a web of concepts joined by labeled arrows, such as 'canary — is a — bird' and 'bird — can — fly', so a program can follow the links., semantic searchsemantic search, n.: Search that understands what you mean, not just the words you typed, so a search for 'cheap places to stay' also finds 'budget hotels'., semantic websemantic web, n.: An effort to label data on the web in a standard, precise way so that programs, not only human readers, can tell what it means and connect facts drawn from many different sites., WordNetWordNet, prop. n.: A hand-made map of English vocabulary in which words sharing a meaning are bundled together and the bundles are linked — recording, say, that a dog is a kind of animal and a wheel is part of a car., description logicdescription logic, n.: A family of precise logical languages for defining categories and how they relate, such as 'a parent is a person with at least one child', designed so that a computer's reasoning about them always finishes., knowledge acquisition bottleneckknowledge acquisition bottleneck, n.: The problem that getting knowledge out of human experts and into a computer by hand is so slow and costly that it limited how far classic expert systems could go., knowledge engineeringknowledge engineering, n.: The craft of collecting what human experts know — through interviews, observation and documents — and turning it into rules or structured data that a computer system can use., Resource Description FrameworkResource Description Framework, prop. n.: A web standard for writing facts as simple three-part statements — subject, relation, object — using web addresses as names, so that data from different sources can be merged automatically., Web Ontology LanguageWeb Ontology Language, prop. n.: A web standard language for writing ontologies — precise definitions of categories and their relationships — so that software can check them for contradictions and infer new facts.