Component-based software development is the current methodology facilitating agility in project management, software reuse in design and implementation, promoting quality and productivity, and increasing the reliability and performability. This paper illustrates the usage of intuitionistic fuzzy degree approach in modelling the quality of entities in imprecise software reliability computing in ...

The paper presents a combined model of reliability and performance (performability model) of two modules in series, each has C components in parallel. The objective of the paper is to illustrate the effect of the reliability on the performance. The paper emphasizes homogeneous continuous-time Markov process and queueing approach for reliability and performance models respectively. A numerical e...

Business Process Management (BPM) is an holistic approach for describing, analyzing, managing, improving and executing large enterprise business processes, which can be seen as a number of related tasks that have to be executed in order to reach well-defined objectives. This paper introduces an approach to the specification and management of the resources that are associated to each BP task and...

Markov-reward models, as extensions of continuous-time Markov chains, have received increased attention for the specification and evaluation of performance and dependability properties of systems. Until now, however, the specification of reward-based performance and dependability measures has been done manually and informally. In this paper, we change this undesirable situation by the introduct...

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...

This paper introduces an analytical method for approximating the performability of a firm realtime system modeled by a multi-server queue. The service discipline in the queue is earliestdeadline-first (EDF), which is an optimal scheduling algorithm. Real-time jobs with exponentially distributed relative deadlines arrive according to a Poisson process. All jobs have deadlines until the end of se...

Markov reward models are an important formalism by which to obtain dependability and performability measures of computer systems and networks. In this context, it is particularly important to determine the probability distribution function of the reward accumulated during a nite interval. The interval may correspond to the mission period in a mission-critical system , the time between scheduled...

Markov models are commonly used to asses the dependability/performability of fault-tolerant systems. Computation of many dependability/performability measures for repairable fault-tolerant systems requires the transient analysis of irreducible Markov models. Examples of such measures are the unavailability at time and the -expected interval unavailability at time . Randomization (also called un...

The ≼Φ stochastic comparison (≼Φ∈ {≼st, ≼wk, ≼wk∗}) of multidimensional Continuous Time Markov Chains (CTMC)s is an efficient but a complex method for the performability evaluation of computer systems. Different techniques can be applied for the stochastic comparison of Markov chains. The coupling is an intuitive method, and may be applied by comparing the evolution of sample paths due to event...

Fault-tolerant systems with repair-upon-failure strategy can become expensive in terms of labour and time. While postponing these repairs, it is essential to keep the whole system capable to deal with user requests. For this purpose, usually, a threshold value is defined which represents the minimum number of servers the system administrator should keep operative. Highly available multiprocesso...