Performability modelling and analysis is used as a measure of both performance and dependability of, mainly, fault-tolerant systems. Proxels are a paradigm that provides deterministic analysis of discrete stochastic models which contain general types of distribution functions, which is not otherwise possible using the standard approaches, such as discrete-event simulation or Markov reward model...

In this paper, we discuss issues in performability modeling of \software rejuvenation," a form of software fault tolerance based on occasionally cleaning up the operational environment. System factors which play a key role in such a model are identi ed. Among these, we comment on two issues of particular interest when modeling software rejuvenation: (1) the representation of the degradation in ...

Markov Decision Processes (MDPs) and Partially Observable MDPs (POMDPs) have been proposed as a framework for performability management. However, exact solution of even small POMDPs is very difficult because of their potentially infinite induced state spaces. In this paper, we present new lower bounds on the accumulated reward measure for MDPs and POMDPs. We describe how the bounds can be used ...

This paper reviews recent and relevant literature on the role of performability across the sustainable value chain by first introducing pertinent material in green supply chains, life cycle analyses, and EcoDesign methodologies. A new sustainable product life cycle framework is then proposed to represent key lifetime stages of sustainable systems. New research in performability is covered acros...

This paper assumes a user-oriented point of view in examining the performability of a dependable omputing system. The investigated performability measure is the e e tive time that a task, with an assigned work requirement, takes to be exe uted by the system. Assuming that the system hanges its performan e hara teristi s randomly in time, the sto hasti model representing the task ompletion time ...

Beowulf clusters are very popular because of the high computational power they can provide at reasonably low costs. However, the most pressing issues of today’s cluster solutions are the need for high availability and performance. Cluster systems are clearly prone to failures. Even if cover is provided with some probability c, there would be reconfiguration and/ or rebooting delays to resume th...