The use of PKI in large scale environments suffers some inherent problems concerning the options to adopt for the optimal cost-centered operation of the system. In this paper a Markov based probability model has been applied and a performability indicator has been introduced for assisting the evaluation of the operational cost of the system in a decision support process. Considering the unavail...

The authors present a new approach for the automated generation of test cases to be used for demonstrating the reliability of large industrial mission-critical systems. In this study they extend earlier work by using a performability model to track resource usage and resource failures. Results from the transient Markov chain analysis are used to estimate the software reliability at a given syst...

The author’s realization of Philippe Boesmans’ Daydreams, for marimba and electronics, was a study in the musical relationships between performers and computers. This realization can be used to reflect a performer’s interpretation of the score through a performer-oriented user interface. The new version honors the composer’s intentions but eliminates the need for excessive hardware devices and ...

The calculation of the distribution of a linear combination of order statistics from random variables that are uniformly distributed is considered. A simple recursion to compute this distribution is presented that, unlike previous methods, is numerically stable and efficient. As such, this should be the algorithm of choice when the linear combination distribution needs to be obtained. (Reliabil...

Multiprocessor system models at present are very important and widely used in modelling transaction processing systems, communication networks, mobile networks, and flexible machine shops with groups of machines. Heterogeneous processors system with one faster main server and several identical servers are studied. In this paper reconfiguration and rebooting delays are considered to study the pe...

Dependable LQNS is a software tool for modeling and evaluating performability of fault-tolerant layered distributed applications that use a separate architecture for failure detection and reconfiguration. It takes into account the effects of management architecture, application software architecture, failure of management and application components in the dependability computation. It uses a co...

Stochastic Process Algebras (SPA) have been proposed as compositional specification formalisms for quantitative models. Here we apply these compositional features to SPAs extended by rewards. State space reduction of performability models can be achieved based on the behaviour-preserving notion of Markov Reward Bisimulation. For a framework extended by immediate actions we develop a new equival...

The SHARPE package is now 1 3 y ears old. A w ell known package in the eld of reliability and performability, SHARPE is used in universities as well as in companies. Many important c hanges have been made during these years to improve the satisfaction of our users. Recently several new algorithms have been added and a Graphical User Interface has been implemented. This paper presents the curren...