Information services for the Web: Building and maintaining domain models

The World Wide Web serves as a leading vehicle for information disseminatio n by offering information services, such as product information, group inte ractions, or sales transactions. Three major factors affect the performance and reliability of information services for the Web, namely the distributi on of information which has resulted from the globalization of information systems, the heterogeneity of information sources, and the sources' instabi lity caused by autonomous evolution. This paper focuses on integrating exis ting information sources, available via the Web, in the delivery of informa tion services. The primary objective of the paper is to provide mechanisms for structuring and maintaining domain models for Web applications. These m echanisms are based on conceptual modeling techniques, where concepts are b eing defined and refined within a metadata repository through the use of in stantiation, specialization and attribution. Also, active databases techniq ues are exploited to provide robust mechanisms for maintaining a consistent domain model in a rapidly evolving environment, such as the Web. Therefore , the main contribution of the paper lies in the provision of an architectu re for semi-automatic generation and maintenance of user-oriented, semantic -based domain models that describe distributed heterogeneous information so urces.