Displaying similar documents to “Approximation of Reliability for a large system with non-markovian repair-times”

An Extended Opportunity-Based Age Replacement Policy

Bermawi P. Iskandar, Hiroaki Sandoh (2010)

RAIRO - Operations Research

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The present study proposes an extended opportunity-based age replacement policy where opportunities occur according to a Poisson process. When the age, of the system satisfies for a prespecified value , a corrective replacement is conducted if the objective system fails. In case satisfies for another prespecified value , we take an opportunity to preventively replace the system by a new one with probability , and do not take the opportunity with probability . At the moment reaches...

Approximation by harmonic polynomials in star-shaped domains and exponential convergence of Trefftz hp-dGFEM

Ralf Hiptmair, Andrea Moiola, Ilaria Perugia, Christoph Schwab (2014)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

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We study the approximation of harmonic functions by means of harmonic polynomials in two-dimensional, bounded, star-shaped domains. Assuming that the functions possess analytic extensions to a -neighbourhood of the domain, we prove exponential convergence of the approximation error with respect to the degree of the approximating harmonic polynomial. All the constants appearing in the bounds are explicit and depend only on the shape-regularity of the domain and on . We apply the obtained...

Fast approximation of minimum multicast congestion – Implementation VERSUS Theory

Andreas Baltz, Anand Srivastav (2010)

RAIRO - Operations Research

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The problem of minimizing the maximum edge congestion in a multicast communication network generalizes the well-known -hard multicommodity flow problem. We give the presently best theoretical approximation results as well as efficient implementations. In particular we show that for a network with edges and multicast requests, an OPT + exp(1)ln)-approximation can be computed in lnln) time, where  bounds the time for computing an -approximate minimum Steiner tree. Moreover, we present...

An approximation theorem for sequences of linear strains and its applications

Kewei Zhang (2010)

ESAIM: Control, Optimisation and Calculus of Variations

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We establish an approximation theorem for a sequence of linear elastic strains approaching a compact set in by the sequence of linear strains of mapping bounded in Sobolev space . We apply this result to establish equalities for semiconvex envelopes for functions defined on linear strains a construction of quasiconvex functions with linear growth.

Differential approximation of NP-hard problems with equal size feasible solutions

Jérôme Monnot (2010)

RAIRO - Operations Research

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In this paper, we focus on some specific optimization problems from graph theory, those for which all feasible solutions have an equal size that depends on the instance size. Once having provided a formal definition of this class of problems, we try to extract some of its basic properties; most of these are deduced from the equivalence, under differential approximation, between two versions of a problem  which only differ on a linear transformation of their objective functions. This...

Survival probabilities of autoregressive processes

Christoph Baumgarten (2014)

ESAIM: Probability and Statistics

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Given an autoregressive process of order (  =   + ··· +   +  where the random variables , ,... are i.i.d.), we study the asymptotic behaviour of the probability that the process does not exceed a constant barrier up to time (survival or persistence probability). Depending on the coefficients ,...,...