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Introduction to KnowledgeEngineering

Ontology , Knowledge Base

GMU IT344 Fall 2013Prof. Vera Goodacre

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What is Ontology ?

Philosophical senseWhat is existence?What are the meanings of being ?Into what categories can we divide existingthings ?

Computer science

Computational models that enable certain kind ofautomated reasoning

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Database versus Knowledge base

Databasedefines data andvia conceptual schema relations on dataData is expressible in ground atomic facts

Ontology (Knowledge base)Defines terms with which to represent knowledge

Ontology defines its vocabulary and builds on itKnowledge can be expressed with logicalsentences and variables

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Ontology / Knowledge Base

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Property types for the relation type Employment(employed-by)

From Helsinki University of Technology TAI research center

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Ontology / Knowledge Base

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Knowledge is presented as instances of concepts From HUT TAI research center

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Ontology / Knowledge Base

Ontology isSpecification of a representational vocabulary for aspecific domain

Study of category of things that may exist in somedomainKey challenge

How to share knowledge between domains

Attempts to formalize approach to building ontologies :KIF Knowledge Interface FormatLisp like notation

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Example : Vehicle ontology

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From Basic Ontology Processes

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Ontology processes

How to process knowledge in the ontologyElaboration

Uses inheritance (upward search to get

information)ElicitationDownward search to get information for aspecific node

Information RetrievalLocate a node and information from itsneighborhood

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Ontology processes

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From Basic Ontology Processes

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Advanced Ontology processes

Dynamic IntegrationPropagates the new information via several nodes

Classification , generalization

Ontology based inferencesThe ultimate goal of field of automated reasoningis to model and emulate human thinking processes.The basis for any inference process is a formal

system, ontology provides such example - used inKnowledge Acquisition systems

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