Transitioning web application frameworks towards the Semantic Web

Applications utilising the Semantic Web are currently developed mostly on a case-bycase basis, although they share common capabilities and architectures. In contrast, the implementation of Web applications is supported by a wide range of mature frameworks, which provide the infrastructure for the applications in the form of libraries and components. The components in turn are based on software patterns, which provide solutions for recurring design problems. To address this situation we propose seven architectural patterns for Semantic web applications which are called semantic viewer, semantic portal, semantic annotation, semantic repository, semantic authoring, web application environment and desktop application environment. These patterns can be used (i) to evaluate current approaches to support the development of such applications, and (ii) to recommend functionality for future Semantic Web application frameworks. The architectural patterns are based on both a theoretical and an empirical basis. The theoretical capabilities of the Semantic Web have been determined by doing a review of the influences, design principles and standards related to the Semantic Web. The empirical basis is provided by a survey of 50 applications utilising Semantic Web technologies from two key challenges in the domain of software engineering for the Semantic Web. We list the user interfaces and back-end components of each pattern, and provide two examples from the survey which implement the architecture of the pattern. Additionally a pattern language for Semantic Web applications is given, which describes how to assemble an application by combining patterns, components and interfaces. Finally, we evaluate the patterns in two steps. First a catalogue relating current Semantic Web tools and frameworks to the parts of the patterns is provided. Secondly, we describe our example implementation of the semantic portal pattern in an application for exploring social communities on the web.