Download Lecture 11

Building Trustworthy
Semantic Webs
Lecture #11: Ontology Engineering
Dr. Bhavani Thuraisingham
September 25, 2006
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Objective of the Unit
0 This unit will provide an overview of the software engineering
aspects of ontologies. The field is called Ontology Engineering
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Outline of the Unit
0 Summary of semantic web technologies discussed so far
0 Applications discussed so far
0 Ontology Engineering
0 Directions
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Semantic web technologies discussed so far
0 XML, XML Schema
0 RDF, RDF Schema
0 Ontology, OWL
0 Logic, Rules, Inference
0 Some discussion of security issues for each technology
- Policy specification, Securing documents
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Types of Application
0 Horizontal Information Products at Elsevier: Integration
0 Data integration at Audi: Integration
0 Skill finding at Swiss Life: Search
0 Think Tank Portal at EnterSearch: Knowledge man agent
0 E-Learning: Knowledge management
0 Web Services: Web services (for any of the other applications
discussed)
0 Multimedia Collection at Scotland Yard: Searching
0 Online Procurement at Daimler Chrysler: E-Business
0 Device Interoperability at Nokia: Interoperability
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Revisiting Ontology
0 Common definitions for any entity, person or thing
0 Several ontologies have been defined and available for use
0 Defining common ontology for an entity is a challenge
0 Mappings have to be developed for multiple ontologies
0 Specific languages have been developed for ontologies
- RDF, OWL, DAML+OIL, etc.
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What is Ontology Engineering?
0 Tools and Techniques to
- Create Ontologies
- Specify Ontologies
- Maintain Ontologies
- Query Ontologies
- Evolve Ontologies
- Reuse Ontologies
- Incorporate features such as security, data quality, integrity
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Manual Constructiob of Ontologues
0 Determine Scope
0 Consider Reuse
0 Enumerate Terms
0 Define Taxonomy
0 Define Properties
0 Define facets
0 Define Instances
0 Check for Anomalies
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Reuseing Exitsing Ontologies
0 The goal is not to reinvent the wheel
0 Several ontologies have been developed for different domains
0 Codieid Bodies of Expert Knowledge
0 Integrated Vocabularies
0 Upper Level Ontologies
0 Topic Hierarchies
0 Linguistic Resources
0 Ontology Libraries
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Semi/Automatics Methods for Ontology
Generation
0 Much of the research is focusing on developing ontologies
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using tools from multiple heterogeneous data sources
Essentially extracting concepts and expanding on concepts
from the data sources
Uses combination of data integration, metadata extraction,
and machine learning techniques
E.g. Clustering of concepts, Classification of concepts etc.
Text Book describes Semantic Web Knowledge Management
Architecture
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What is Knowledge Management?
0 Knowledge management, or KM, is the process through which
organizations generate value from their intellectual property and
knowledge-based assets
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KM involves the creation, dissemination, and utilization of
knowledge
0 Ontologies are a form of Knowledge?
0 Reference: http://www.commerce-database.com/knowledge-
management.htm?source=google
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Directions
0 Need tools for developing semantic web technologies
- XML documents, RDF documents, Ontologies, etc.
0 How to integrate the multiple ontologjes and tools?
0 Role of Agents – agents are processes that reasons with semantic
web technologies
0 Semantic web services, data mining, knowledge management
integrated