computer science Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to Applied science, practical discipli ...

and

artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech re ...

, ontology languages are

formal language In logic, mathematics, computer science, and linguistics, a formal language consists of words whose letters are taken from an alphabet and are well-formed according to a specific set of rules. The alphabet of a formal language consists of symb ...

s used to construct ontologies. They allow the encoding of

knowledge Knowledge can be defined as awareness of facts or as practical skills, and may also refer to familiarity with objects or situations. Knowledge of facts, also called propositional knowledge, is often defined as true belief that is distinc ...

about specific domains and often include reasoning rules that support the processing of that knowledge. Ontology languages are usually

declarative language In computer science, declarative programming is a programming paradigm—a style of building the structure and elements of computer programs—that expresses the logic of a computation without describing its control flow. Many languages that a ...

s, are almost always generalizations of frame languages, and are commonly based on either first-order logic or on description logic.

Classification of ontology languages

Classification by syntax

Traditional syntax ontology languages

* Common Logic - and its dialects *

CycL CycL in computer science and artificial intelligence is an ontology language used by Doug Lenat's Cyc artificial intelligence project. Ramanathan V. Guha was instrumental in the design of early versions of the language. There is a close variant ...

DOGMA Dogma is a belief or set of beliefs that is accepted by the members of a group without being questioned or doubted. It may be in the form of an official system of principles or doctrines of a religion, such as Roman Catholicism, Judaism, Islam ...

(Developing Ontology-Grounded Methods and Applications) *

F-Logic F-logic (frame logic) is a knowledge representation and ontology language. F-logic combines the advantages of conceptual modeling with object-oriented, frame-based languages and offers a declarative, compact and simple syntax, as well as the well-de ...

(Frame Logic) * FO-dot (First-order logic extended with types, arithmetic, aggregates and inductive definitions) * KIF (Knowledge Interchange Format) ** Ontolingua based on KIF * KL-ONE * KM programming language *

LOOM (ontology) Loom is a knowledge representation language developed by researchers in the artificial intelligence research group at the University of Southern California's Information Sciences Institute. The leader of the Loom project and primary architect fo ...

* OCML (Operational Conceptual Modelling Language) *

OKBC Open Knowledge Base Connectivity (OKBC) is a protocol and an API for accessing knowledge in knowledge representation systems such as ontology repositories and object–relational databases. It is somewhat complementary to the Knowledge Interchang ...

( Open Knowledge Base Connectivity) * PLIB (Parts LIBrary) * RACER

Markup ontology languages

These languages use a markup scheme to encode knowledge, most commonly with

XML Extensible Markup Language (XML) is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. T ...

. *

DAML+OIL The Web Ontology Language (OWL) is a family of knowledge representation languages for authoring ontologies. Ontologies are a formal way to describe taxonomies and classification networks, essentially defining the structure of knowledge for variou ...

* Ontology Inference Layer (OIL) * Web Ontology Language (OWL) *

Resource Description Framework The Resource Description Framework (RDF) is a World Wide Web Consortium (W3C) standard originally designed as a data model for metadata. It has come to be used as a general method for description and exchange of graph data. RDF provides a variety of ...

(RDF) *

RDF Schema RDF Schema (Resource Description Framework Schema, variously abbreviated as RDFS, , RDF-S, or RDF/S) is a set of classes with certain properties using the RDF extensible knowledge representation data model, providing basic elements for the descr ...

(RDFS) *

SHOE A shoe is an item of footwear intended to protect and comfort the human foot. They are often worn with a sock. Shoes are also used as an item of decoration and fashion. The design of shoes has varied enormously through time and from culture t ...

Controlled natural languages

* Attempto Controlled English

Open vocabulary natural languages

* Executable Englishwww.executable-english.com
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Classification by structure (logic type)

Frame-based

Three languages are completely or partially frame-based languages. *

* KM

Description logic-based

Description logic provides an extension of frame languages, without going so far as to take the leap to first-order logic and support for arbitrary predicates. * KL-ONE * RACER * OWL.

Gellish Gellish is an ontology language for data storage and communication, designed and developed by Andries van Renssen since mid-1990s. It started out as an engineering modeling language ("Generic Engineering Language", giving it the name, "Gellish") bu ...

is an example of a combined ontology language and ontology that is description logic based. It distinguishes between the semantic differences among others of: * relation types for relations between concepts (classes) * relation types for relations between individuals * relation types for relations between individuals and classes It also contains constructs to express queries and communicative intent.

First-order logic-based

Several ontology languages support expressions in first-order logic and allow general predicates. * Common Logic *

* FO-dot (First-order logic extended with types, arithmetic, aggregates and inductive definitions) * KIF

Notes

References

* Oscar Corcho, Asuncion Gomez-Perez,
A Roadmap to Ontology Specification Languages
' (2000)
''Introduction to Description Logics'' – DL course
by Enrico Franconi, Faculty of Computer Science, Free University of Bolzano, Italy {{Non-classical logic Modeling languages