Demystifying Ontologies

Demystifying Ontology

International UDC Seminar 2011 “Classification & Ontology:Formal Approaches and Access to Knowledge”

19 Sept 2011

Emad Khazraee, Drexel UniversityXia Lin, Drexel University

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Agenda

► Introduction

► What is Ontology?

► Ontology Spectra

► Ontology Gamut

► Conclusion

► Q & A Discussion

19 September 2011Classification & Ontology, The Hague, Netherlands

319 September 2011Classification & Ontology, The Hague, Netherlands

Introduction► This talk is aimed to be a motivation for a

discussion

► The term “ontology” is used in different communities multifariously

► Scientific practice needs communication and cooperation

► Ontologies as a “Boundary Objects”

419 September 2011Classification & Ontology, The Hague, Netherlands

Introduction

► A cool ontology!

519 September 2011Classification & Ontology, The Hague, Netherlands

What is Ontology (or ontology)?

► Metaphysics, first philosophy

► Ontos and logos (being and word)

► Early 17th century Jacob Lorhard Rudolf Göckel

► Formal ontology used by Husserl in Logical Investigation. Formal vs Formalized!!

► In 1980’s it emerged in computer & information community

619 September 2011Classification & Ontology, The Hague, Netherlands

What is Ontology (or ontology)?► Ontology as a discipline (“O”)

The attempt to answer the question of “what is, of the kinds and structures of objects, properties, events, processes and relations” (Smith & Welty)

Definitive and exhaustive classification

► Ontology as artifact (“o”) An knowledge engineering artifact Designed for a purpose , Enable knowledge modeling, Uses a formal language

719 September 2011Classification & Ontology, The Hague, Netherlands

What is Ontology (or ontology)?► Formal in two senses:

First, deals with general categories such as thing, process, and matter— and deploys these categories to codify what exists

the use of symbolism in a deductive system

► Formal ontology and formalized ontology

► ontology-as-categorial-analysis (ontology_c) and ontology-as-technology (ontology_t) (Poli & Obrst)

819 September 2011Classification & Ontology, The Hague, Netherlands

What is Ontology (or ontology)?► “A formal specification of a conceptualization”

(Gruber,1993)

► Kinds and Structures as categories► A set of terms or vocabulary can be structured to

form a hierarchy or lattice ► “A dictionary of terms formulated in a canonical

syntax and with commonly accepted definitions designed to yield a lexical framework for knowledge-representation which can be shared by different communities” (Smith, 2003)

► Definitions and a supporting framework of axioms.

919 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Spectra

Ontology spectrum based on formal semanticsAdapted from (Daconta, Obrst & Smith, 2003)

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Ontology spectrum based on formal structureadapted from (McGuinness, 2003)

19 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Spectra

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Ontology spectrum based on formal complexityadopted from (Smith & Welty, 2001)

19 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Spectra

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Ontology spectrum based on formalityadopted from (Guarino, Oberle & Staab, 2009)

19 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Spectra

1319 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Spectra► “A set of axioms, i.e. a logical theory designed to

capture the intended models corresponding to a certain conceptualization and to exclude unintended ones” (Guarino, Oberle & Staab)

► “An ontology is a formal theory within which not only definitions but also a supporting framework of axioms is included” (Smith)

1419 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Gamut► Each spectra underline one dimension

Degree of semantics, expressivity, formality and complexity Semantic richness

► They are not necessarily positively correlated

► We propose to use two dimensions to have a better description (degree of formalization and semantic richness) Why not three?

1519 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Gamut

1619 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Gamut► What do these dimensions mean?

Difference in semantic richness and semantic specification (clearly refer to something)

► Three ontology families

► Main community of users of each family

► Audience of each family

1719 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Gamut► This gamut can be considered as a clan of

knowledge engineering artifacts► This clan consists of three families of ontologies

which have relations and shared interest

► Ontology as a discipline can be seen as the neighboring community

► Mutual benefits of this neighborhood

1819 September 2011Classification & Ontology, The Hague, Netherlands

Ontology Gamut

► To what extent we can specify these two dimensions to be used operationally?

► How can we use ontologies as boundary objects? Boundary objects have different meanings in different social worlds but

their structure is common enough to more than one world to make them recognizable, a means of translation. The creation and management of boundary objects is a key process in developing and maintaining coherence across intersecting social worlds.

(Star, & Griesemer, 1989)

Demystifying Ontology

International UDC Seminar 2011 “Classification & Ontology:Formal Approaches and Access to Knowledge”

19 Sept 2011

Thank YouQuestions & Discussion?

emad@drexel.eduxlin@drexel.edu