Gerardo Rubino – författare

Rare Event Simulation In a probabilistic model, a rare event is an event with a very small probability of occurrence. The forecasting of rare events is a formidable task but is important in many areas. For instance a catastrophic failure in a transport system or in a nuclear power plant, the failure of an information processing system in a bank, or in the communication network of a group of banks, leading to financial losses. Being able to evaluate the probability of rare events is therefore a critical issue. Monte Carlo Methods, the simulation of corresponding models, are used to analyze rare events. This book sets out to present the mathematical tools available for the efficient simulation of rare events. Importance sampling and splitting are presented along with an exposition of how to apply these tools to a variety of fields ranging from performance and dependability evaluation of complex systems, typically in computer science or in telecommunications, to chemical reaction analysis in biology or particle transport in physics. Graduate students, researchers and practitioners who wish to learn and apply rare event simulation techniques will find this book beneficial.

Performability modelling and evaluation brings together two disciplines that have long been treated separately in different communities: computer and communication system performance evaluation and system reliability and availability evaluation.* Provides a single-source reference covering of all aspects of performability evaluation.* Introduces a new approach to assessing the performance and dependability of systems thus revealing system characteristics that cannot be uncovered separately by performance or reliability evaluation.* Explains how systems can operate partially in the presence of failures by discussing:-Capacity of failure prone clusters of transaction processing systems.-Network throughput when network nodes and links fail.-Task completion times on degradable multiprocessor systems.-A variety of modelling and evaluation techniques.* Features software tool descriptions to support performability evaluations as well as an extensive bibliography.Computer scientists and engineers will find this excellent overview compulsive reading as will postgraduates and researchers in computer science and related fields.

Dependability metrics are omnipresent in every engineering field, from simple ones through to more complex measures combining performance and dependability aspects of systems. This book presents the mathematical basis of the analysis of these metrics in the most used framework, Markov models, describing both basic results and specialised techniques. The authors first present both discrete and continuous time Markov chains before focusing on dependability measures, which necessitate the study of Markov chains on a subset of states representing different user satisfaction levels for the modelled system. Topics covered include Markovian state lumping, analysis of sojourns on subset of states of Markov chains, analysis of most dependability metrics, fundamentals of performability analysis, and bounding and simulation techniques designed to evaluate dependability measures. The book is of interest to graduate students and researchers in all areas of engineering where the concepts of lifetime, repair duration, availability, reliability and risk are important.