General description of research activities

(from around 2002)

Our research lies at the cross-section of three domains, namely distributed systems management, development methodologies for distributed multimedia applications, and protocols for advanced Internet applications. Performance management is one of the concerns of distributed systems management, and quality of service (QoS) management has emerged as one of the important issue in this area. In the context of Internet applications, the problem of QoS management occurs at two levels: First, at the network level; here the question is how to provide some form of quality guarantee for data transmission in the context of the global Internet or in a private intranet which spans some local or international organization. (Note: This also includes wireless and mobile network access). Second, QoS management must be seen at the application level; here the different system components, such as client workstation (or the hand-held communication device of the future), various server computers and the intervening networks must collaborate to provide the application services with appropriate quality and cost. The considered QoS parameters include video and audio presentation quality, response time, quality of information presented, and cost. Our research is mainly concerned with QoS management at the application level.

One of our premises is that distributed applications must be able to adapt to the constraints of their execution environments. One of the orientations of our research is therefore aimed at developing methods and approaches which are helpful for the construction of adaptive distributed multimedia applications. We believe that this kind of work, which is of methodological nature, can only be done in a meaningful manner if it is based on a sufficiently large sample of practical examples. Therefore we work on prototypes of adaptive applications which provide an opportunity for evaluating our development methods and/or for finding new methodological approaches to the development of these systems.

In addition to this work aimed at multimedia applications, we also do some software engineering research on development methods for distributed real-time systems, in general. This work is oriented towards object-oriented development methods for requirements and specifications, possibly using formal methods. Special attention is given to verification and validation methods, including (partially) automated test generation, and automated methods for deriving protocols from communication services and control modules for real-time control applications.