Frederic Majer

Roadmap towards Lifecycle Support for Highly Distributed Web-Based Systems

To cope with the increased complexity of todaypsilas Web-based systems, approaches facilitating operations, maintenance and evolution of heterogeneous and distributed systems landscapes are vital. In particular, due to the complex interdependencies between their distributed system parts, assuring that services are delivered at a high level of quality is challenging. To this end, we present the integrated information map (i2map) as an aspect-oriented approach. It considers these interdependencies as first-class citizens and provides sophisticated services addressing the lifecycle support of distributed systems. We exemplarily demonstrate the approachpsilas potential in the context of ontology-based evaluation of service level agreements in a highly interrelated system landscape.

Capturing the essentials of federated systems

Today, the Web is increasingly used as a platform for distributed services, which transcend organizational boundaries to form federated applications. Consequently, there is a growing interest in the architectural aspect of Web-based systems, i.e. the composition of the overall solution into individual Web applications and Web services from different parties. The design and evolution of federated systems calls for models that give an overview of the structural as well as trust-specific composition and reflect the technical details of the various accesses. We introduce the WebComposition Architecture Model (WAM) as an overall modeling approach tailored to aspects of highly distributed systems with federation as an integral factor.

Construction by linking: the linkbase method

The success of many innovative Web applications is not based on the content they produce -- but on how they combine and link existing content. Older Web Engineering methods lack flexibility in a sense that they rely strongly on a-priori knowledge of existing content structures and do not take into account initially unknown content sources. We propose the adoption of principles that are also found in Component-based Software Engineering, to assemble highly extensible solutions from reusable artifacts. The main contribution of our work is a support system, consisting of a central service that manages n:m relationships between arbitrary Web resources, and of Web application components that realize navigation, presentation, and interaction for the linked content.

Component-based content linking beyond the application

The content of many innovative Web sites today often originates from beyond the application. This paper is concerned with building Web applications that heavily integrate and link content from external sources, like e.g. Web services or RSS feeds. Unlike conventional applications, they are characterized by a very dynamic and distributed information space. In this context, traditional Web Engineering approaches suffer from the fact that they rely too much on a-priori knowledge of existing content structures. We present a support system and a method for building such applications in a very flexible way. Flexibility is achieved by managing links separately from the content in a dedicated Web service and by composing the application from fine-grained, reusable components that realize navigation, presentation, and interaction for the linked content.