32 research outputs found

    A note on the central limit theorem for a one-sided reflected Ornstein-Uhlenbeck process

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    In this short communication we present a (functional) central limit theorem for the idle process of a one-sided reflected Ornstein-Uhlenbeck proces

    Minimising MCMC variance via diffusion limits, with an application to simulated tempering

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    We derive new results comparing the asymptotic variance of diffusions by writing them as appropriate limits of discrete-time birth-death chains which themselves satisfy Peskun orderings. We then apply our results to simulated tempering algorithms to establish which choice of inverse temperatures minimises the asymptotic variance of all functionals and thus leads to the most efficient MCMC algorithm.Comment: Published in at http://dx.doi.org/10.1214/12-AAP918 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    One-dimensional reflected diffusions with two boundaries and an inverse first-hitting problem

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    We study an inverse first-hitting problem for a one-dimensional, time-homogeneous diffusion X(t)X(t) reflected between two boundaries aa and b,b, which starts from a random position η.\eta. Let a≤S≤ba \le S \le b be a given threshold, such that P(η∈[a,S])=1,P( \eta \in [a,S])=1, and FF an assigned distribution function. The problem consists of finding the distribution of η\eta such that the first-hitting time of XX to SS has distribution F.F. This is a generalization of the analogous problem for ordinary diffusions, i.e. without reflecting, previously considered by the author

    On the generalized drift Skorokhod problem in one dimension

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    We show how to write the solution to the generalized drift Skorokhod problem in one-dimension in terms of the supremum of the solution of a tractable unrestricted integral equation (that is, an integral equation with no boundaries). As an application of our result, we equate the transient distribution of a reflected Ornstein–Uhlenbeck (OU) process to the first hitting time distribution of an OU process (that is not reflected). Then, we use this relationship to approximate the transient distribution of the GI/GI/1 + GI queue in conventional heavy traffic and the M/M/N/N queue in a many-server heavy traffic regime

    The impact of reneging in processor sharing queues

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    We investigate an overloaded processor sharing queue with renewal arrivals and generally distributed service times. Impatient customers may abandon the queue, or renege, before completing service. The random time representing a customer’s patience has a general distribution and may be dependent on his initial service time requirement. We propose a scaling procedure that gives rise to a fluid model, with nontrivial yet tractable steady state behavior. This fluid model captures many essential features of the underlying stochastic model, and we use it to analyze the impact of impatience in processor sharing queues. We show that this impact can be substantial compared with FCFS, and we propose a simple admission control policy to overcome these negative impacts
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