Aspects of Semantic Data Modeling in Hypermedia Systems

The World Wide Web is a vast global distributed hypermedia system providing an access to large amount of hypermedia information. This thesis analyzes the possibilities to support different knowledge transfer processes on the Web. Such processes might improve facilities for managing or retrieving hypermedia information on the Web. To analyze such possibilities this thesis looks on the Web from the data modeling point of view. Thus, the thesis identifies the logical, physical and semantic data model of the Web. Further, the thesis shows that in order to support a number of different knowledge transfer processes we must apply novel semantic data modeling approaches to the Web. The thesis presents three such novel semantic data models: HC-Data model, Knowledge Domains and Knowledge Cards, which support Web-based knowledge structuring, Web-based knowledge profiling and Web-based knowledge mining, respectively. HC-Data model extends the well-known concept of hypermedia composites allowing authors to define appropriate roles for members of their hypermedia composites. Composites created in this way represent well-defined chunks of structured knowledge in a hypermedia form. Knowledge Domains provide profiled global overviews of hypermedia resources in Web applications. Such overviews consist of a number of semantic entities interrelated by means of semantic relationships. In order to create these overviews, hypermedia resources might be assigned to these semantic entities and their relationships. Accessing hypermedia information structured by means of Knowledge Domains is achieved through semantic browsing and structured semantic querying. Knowledge Cards extend the concept of Knowledge Domains by exploiting important properties (infer possibility) of such semantic data structures. Thus, accessing a Knowledge Card results in accessing both: assigned hypermedia resources as well as inferred hypermedia resources. This greatly facilitates an initial access to best-match hypermedia resources on the Web. The thesis presents the implementation of these semantic data modeling approaches in a Web environment. Finally, the thesis provides the overview of related work and suggests few ideas for further development.