Demystifying Ontology International UDC Seminar 2011 Classification & Ontology: Formal Approaches and Access to Knowledge 19 Sept 2011 Emad Khazraee, Drexel University Xia Lin, Drexel University
Agenda Introduction What is Ontology? Ontology Spectra Ontology Gamut Conclusion Q & A Discussion 19 September 2011 2
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 19 September 2011 3
Introduction A cool ontology! 19 September 2011 4
What is Ontology (or ontology)? Metaphysics, first philosophy Ontos and logos (being and word) Early 17 th 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 19 September 2011 5
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 19 September 2011 6
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) 19 September 2011 7
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. 19 September 2011 8
Ontology Spectra Ontology spectrum based on formal semantics Adapted from (Daconta, Obrst & Smith, 2003) 19 September 2011 9
Ontology Spectra Ontology spectrum based on formal structure adapted from (McGuinness, 2003) 19 September 2011 10
Ontology Spectra Ontology spectrum based on formal complexity adopted from (Smith & Welty, 2001) 19 September 2011 11
Ontology Spectra Ontology spectrum based on formality adopted from (Guarino, Oberle & Staab, 2009) 19 September 2011 12
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) 19 September 2011 13
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? 19 September 2011 14
Ontology Gamut 19 September 2011 15
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 19 September 2011 16
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 19 September 2011 17
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) 19 September 2011 18
Demystifying Ontology International UDC Seminar 2011 Classification & Ontology: Formal Approaches and Access to Knowledge 19 Sept 2011 Thank You Questions & Discussion? emad@drexel.edu xlin@drexel.edu