Ram Chakka

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Chakka, R. and I. Mitrani, Heterogeneous multiprocessor systems with breakdowns: A model of a system with N parallel processors subject to occasional interruptions of service, and a common unbounded queue fed by a Poisson arrival stream, is analyzed in the steady state. The service, breakdown and repair characteristics may vary from processor to processor.(More)
Open queuing network systems are useful in the computer industry. In this paper, a multi-node open network, with heterogeneous nodes, each node serving external as well as routed internal arrivals of jobs is considered. The nodes are prone to failures and repairs, the buffers are of finite size. An approximate performability model is developed based on an(More)
A new queue, referred to here as the HetSigma queue, in the Markovian framework, is proposed in order to model nodes in modern telecommunication networks. The queue has many of the necessary ingredients, such as joint (or individual) Markov modulation of the arrival and service processes, superposition of K CPP (compound Poisson process) streams of(More)
A new queuing model is proposed for the performance evaluation of the High Speed Downlink Packet Access (HSDPA) protocol, with respect to a specified user, in UMTS networks. The model is based on the recently evolved MM &#931;<i><sup>&#922;</sup><sub>&#954;= </sub>CPP<sub>&#954;</sub>GEcLG</i>-queue<sup>1</sup>, in which the number of servers allocated to a(More)
In this paper the MM K k=1 CP P k /GE/c/L G-queue is introduced and proposed as a generalised Markovian node model in telecommunications networks. An exact and computationally efficient solution is obtained for the steady-state probabilities and performance measures. Issues concerning the computational effort are also discussed. The proposed queue is(More)
1 Extended abstract Consider a system parallel processors where ~ identical serve a common? unbounded job queue. The processors break down from time to time, and return to an operative state after being repaired. When operative, each processor serves jobs, one ZJt a time, and each job is allowed to occupy at most one operative processor at a time. Let I(t)(More)