Exercise 1 Let us consider a system composed of n different components denoted 1, 2 ……n, with m identical replicas of each component. Two redundancy strategies are studied:-GR, in which redundancy is applied globally at the system level: the architecture is composed of m identical copies of the system that are organized according to a parallel structure.-LR, in which redundancy is applied local...

Modern storage systems are often large complex distributed systems. Current techniques for evaluating their reliability function require the solution of a system of differential equations. We present a more elementary, intuitive approach that focuses on the steady-state behavior of each storage organization when it goes through repeated cycles of failures succeeded by repairs. As a result, our ...

This paper tries to represent a new method for computing the reliability of a system which is arranged in series or parallel model. In this method we estimate life distribution function of whole structure using the asymptotic Extreme Value (EV) distribution of Type I, or Gumbel theory. We use EV distribution in minimal mode, for estimate the life distribution function of series structure and ma...

This paper presents a case study on how to apply ITIL availability management best practice to assess the end-to-end service availability in a tiered web service delivery environment. It also helps pinpoint the road blocks to the required service level and provide cost-effective solution for improved service delivery. An overview of basic ITIL availability management concept is provided along w...

The objective of the study is to compute various reliability parameters for multi-robotic system, using Real Coded Genetic Algorithms (RCGAs) and Fuzzy Lambda-Tau Methodology (FLTM). The paper contains a new idea about the reliability analysis of robotic system. The optimal values of mean time between failures (MTBF) and mean time to repair (MTTR) are obtained using GAs. Petri Net (PN) tool is ...

This paper presents a prediction model for software service availability measured by the mean-time-to-repair (MTTR) and mean-time-to-failure (MTTF) of a service. The prediction model is based on the experimental identification of probability distribution functions for variables that affect MTTR/MTTF and has been implemented using a framework that we have developed to support monitoring and pred...

We derive a sound lower bound on the mean time to failure of periodic systems with (m,k) constraints. We assume that upper bounds on the failure probabilities of each system iteration, e.g., a job or a runtime activation of a periodic task, or a single actuation cycle of a control loop, are known and that they satisfy the IID assumption. Our analysis leverages prior work on the well-studied a-w...

Many different software reliability model.s have been proposed since the publications of the first mc)dels in 1971 [3,2]. Sufficient work has been done to demonstrate that these methods can be used to monitor reliability growth over a useful range of software development projects. }Iowever, the use of software reliability measurement as a management tool is not as widespread as it might be. Par...

Purpose – The purpose of the paper is to develop a conceptual framework that integrates the technology and commercial issues early at the design stage to minimize warranty costs in the most effective and efficient manner and also to develop a model for optimization of warranty with specific focus on reliability and warranty policies. Design/methodology/approach – The critical issues in warranty...

Cloud storage systems typically use three-way random replication to guard against data loss within the cluster, and utilize cluster geo-replication to protect against correlated failures. This paper presents a much lower cost alternative to full cluster geo-replication. We demonstrate that in practical settings, using two replicas is sufficient for protecting against independent node failures, ...