— Behaviour of a complex System consisting of two classes of components L\ and La is considérée, where failure in class L\ results in complete breakdown of the system and that in class L& brings the system to a reduced efficiency state. In class Li failure follows exponential distribution but unlike the earlier studies [1, 2, 4], in class L& bulk failure is assumed. In both the classes, repair ...

We study MX/G/1 nonpreemptive and preemptive-resume priority queues with/without vacations under random order of service (ROS) discipline within each class. By considering the conditional waiting times given the states of the system, which an arbitrary message observes upon arrival, we derive the Laplace-Stieltjes transforms of the waiting time distributions and explicitly obtain the first two ...

We consider an ATM system with an architecture which is designed to accommodate users with very diierent quality of service requirements. In the base case with only two services, sources which require low loss belong to a High Priority class, and share a FCFS buuer, which has priority access to the trunk. A Low Priority class of sources with typically less stringent requirements on loss have a ...

We present the transient analysis of the system content in a two-class discrete-time M X /D/1 priority queue. In particular, we derive an expression for the generating function of the transient system contents of both classes at the beginning of slots. Performance measures are calculated from this generating function. To illustrate our approach we conclude with some examples. c © 2008 Elsevier ...

The Approximation Power of Priority Algorithms Spyros Angelopoulos Doctor of Philosophy Graduate Department of Computer Science University of Toronto 2006 Greedy-like algorithms have been a popular approach in combinatorial optimization, due to their conceptual simplicity and amenability to analysis. Surprisingly, it was only recently that a formal framework for their study emerged. In particul...

We develop a Markov decision process (MDP) model to examine aerial military medical evacuation (MEDEVAC) dispatch policies in a combat environment. The problem of deciding which aeromedical asset to dispatch to each service request is complicated by the threat conditions at the service locations and the priority class of each casualty event. We assume requests for MEDEVAC support arrive sequent...

Due to the unpredictability of mobile network, it is difficult to meet transaction deadlines in a mobile distributed real-time database system (MDRDTBS). We propose the idea of transaction shipping to reduce the overheads in processing a transaction over mobile network and in resolving priority inversion. We consider a distributed lock-based real-time protocol, the Distributed High Priority Two...

This paper presents formulas for calculating waiting time for customers in a queue with combined preemptive and head-ofline (nonpreemptive) priority scheduling disciplines and describes the reasoning behind them. This work has been applied in the development of programmable terminal control units. Introduction The development of programmable terminal control units has created the need for a new...

There are two paradigms proposed to provide QoS for Internet applications: Integrated service (IntServ) and Differentiated service (DiffServ).Intserv is not appropriate for large network like Internet. Because is very complex. Therefore, to reduce the complexity of QoS management, DiffServ was introduced to provide QoS within a domain using aggregation of flow and perclass service. In theses ne...

In this paper, we present a transient analysis of the system contents in a two-class priority queue with single-slot service times. In particular, we derive an expression for the generating function of the transient system contents of both classes. Performance measures are calculated from this generating function. Finally, by means of a numerical example we investigate the impact of the traffic...