A new framework for the extension of stochastic Petri nets (SPNs) is introduced in this paper. SPNs are extended by elements providing means for a dynamic optimization of performability measures. A new type of transition is deened ooering a feature for speciication of controlled switching, called reconngura-tion, from one marking of a SPN to another marking. Optional reconnguration transitions ...

Degradable performance of fault-tolerant computer systems has given rise to considerable interest in mathematical models for combined evaluation of performance and reliability. Most of these models are based upon Markov processes. Several methods have been proposed for the computation of the probability distribution of performability upon an interval of time 0; t]. In this paper, we present a n...

Grid computing offers many scientific and commercial benefits, but also many technical and organisational challenges. This has led to many research areas in traditional distributed systems directing their efforts on to grid systems. Amongst the challenges for grid computing is the need to provide reliable quality of service to end users. This paper seeks to identify some of the challenges and o...

Conclusions Within integrated services digital networks (ISDN), all inter-etzehange signaling messages for ISDN and intelligent network (IN) call controls are carried through a common channel signaling network (CCSN) as a backbone signaling network. Since CCSN usually have very strict reliability requirements as well as good performance objectives, performance and reliability of CCSN need to be...

Reward models have become an important method for specifying performability models for many types of systems. Many methods have been proposed for solving reward models, but no method has proven itself to be applicable over all system classes and sizes. Furthermore, speciication of reward models has usually been done at the state level, which can be extremely cumbersome for realistic models. We ...

In this paper, we propose a framework to analyze Markov reward models, which are commonly used in system performability analysis. The framework builds on a set of analytical tools developed for a class of stochastic processes referred to as Stochastic Hybrid Systems (SHS). The state space of an SHS is comprised of: i) a discrete state that describes the possible configurations/modes that a syst...

In this paper we present a class of nested automata for the modelling of performance, availability, and reliability of software systems with hierarchical structure, which we call systems of systems. Quantitative modelling provides valuable insight into the dynamic behaviour of software systems, allowing non-functional properties such as performance, dependability and availability to be assessed...

Performability is a composite measure for the performance and reliability, which may be interpreted as the cumulative performance over a nite mission time. The computation of its distribution allows the user to ensure that the system will achieve a given performance level. The system is assumed to be modeled as a Markov process with nite state space and a reward rate (performance measure) is as...