Chapter 4 - Semantic Web Application Architecture

Abstract

Many of the components of a Semantic Web application are provided as supported products by companies specializing in Semantic Web technology or by free software under a variety of licenses. New software is being developed by research groups as well as product companies on an ongoing basis. This chapter describes types of components that make up a Semantic Web deployment and how they fit together. The components such as RDF (Resource Description Framework) parsers, serializers, stores, and query engines are not semantic models in themselves but the components of a system that will include semantic models. Even the information represented in RDF is not necessarily a semantic model. These are the building blocks that go into making and using a semantic model. The model will be represented in RDF, to be sure. A semantic model acts as a sort of glue between disparate, federated data sources so one can describe how they fit together. Just as Anyone can say Anything about Any topic, so also can anyone say anything about a model; that is, anyone can contribute to the definition and mapping between information sources. In this way, not only can a federated, RDF-based, semantic application get its information from multiple sources, but it can also get the instructions on how to combine information from multiple sources. In this way, the Semantic Web really is a web of meaning, with multiple sources describing what the information on the Web means.