Distributed and Parallel Systems

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Zsolt Nemeth
Dieter Kranzlmueller
Peter Kacsuk
Jens Volkert


Distributed and Parallel Systems

A selection of best papers of the 4th Austrian-Hungarian Workshop on Distributed and Parallel Systems are presented in this issue. The series of workshops started as a local meeting in 1992 and it grew to an interna- tionally acclaimed event of computing techniques covering not just parallel and distributed programming in the classical sense but also emerging topics like ubiquitous and pervasive computing, cluster and grid technology, multimedia and challenging applications.

Thoai et al focus on a fundamental problem of parallel program development: debugging. Since the execu- tion of parallel programs is nondeterministic, forcing a certain execution trace among the many possible ones requires sophisticated replay techniques. The paper presents how the probe effect can be eliminated and the overhead can be minimised during replay based debugging.

The paper by Lovas et al. presents parallel implementation of an ultra-short range weather prediction method, supported by a graphical development tool, P-GRADE. The paper introduces all stages of the program development from editing to performance analysis.

A novel approach for resource discovery is presented by Juh�asz et al. A grid system should be able to provide brokering services for potentially thousands and millions of resources. Most approaches nowadays are either centralised or flat and in such a way are not really scaleable. The paper proposes a hierarchical fault-tolerant multicast discovery scheme.

The paper by Heinzlreiter et al. presents a grid middleware that enables realising novel interactive visu- alisation systems in grid environments. Tools like the Grid Visualisation Kernel (GVK) are leading towards pioneering grid based Virtual Reality applications.

Fault diagnosis is the central issue of the paper by Polg�ar et al. They propose a modification of P-graph model in order to improve fault diagnosis in complex multiprocessor systems.

B�osa et al. introduce advanced fault tolerating mechanisms for Distributed Maple, a parallel computer alge- bra system. The tolerance of failed links and nodes is enhanced by adding reconnection and restart mechanisms as well as change the virtual root node in order to avoid overall failure. Emerging mobile applications raise the issue of context awareness. Ferscha et al. introduce the techniques related to context sensing, representation and delivery and proposes a new approach for context based mobile computing.

Goldschmidt et al. analyse the requirements of adaptive multimedia servers where the dynamic migration of multimedia applications is supported and an agent-based infrastructure is proposed. The idea is supported by a specification and implementation of a CORBA-based interface. The progress of multimedia over the internet is obvious that raises the need of intelligent video caches. The paper by Schojer et al. introduces a proxy cache that allows fast and efficient adaptation of video based on the MPEG-4 standard.

These papers demonstrate the wide spectrum of the workshop topics: from distributed computing via grids towards novel complex systems.

Zsolt Németh
Dieter Kranzlmüller
Péter Kacsuk
Jens Volkert

Article Details

Introduction to the Special Issue