We study monotonicity results for optimal policies of various queueing and resource sharing models. The standard approach is to prove, for each speciic model, certain properties of the dynamic programming value function. By concentrating on the events instead of the entire value function we come to a uniied treatment of monotonicity results for symmetric two-dimensional models. Several models f...

This master’s thesis gives a brief overview of mathematical modelling of traffic flow from different perspectives. Focus lies on the fluid flow analogy first derived by Lighthill, Whitham and Richards (LWR) in the 1950’s which treats a traffic stream as a compressible one-dimensional fluid. The LWR theory is applied to bottleneck queueing situations, more specifically to junctions with one outg...

Product-form closed queueing networks are widely-used analytical models for the performance analysis of computer and communication systems. Since the publication in 1963 of Jackson’s theorem, the first significant development in the theory of queueing networks, hundreds of papers have been devoted to the topic. Nevertheless, several important theoretical issues remain open. Among these, the eff...

This paper surveys recent work on the stability of open multiclass queueing networks via fluid models. We recapitulate the stability result of Dai [8]. To facilitate study of the converse of the stability result, we distinguish between the notion of fluid limit and that of fluid solution. We define the stability region of a service discipline and the global stability region of a network. Exampl...

Mainstream queueing models are frequently employed in modeling healthcare delivery in a number of settings, and further are used in making operational decisions for the same. The vast majority of these queueing models ignore the effects of delay experienced by a patient awaiting care. However, long delays may have adverse effects on patient outcomes and can potentially lead to longer lengths of...

A main feature of a novel tool is described, the algorthmic translation of formal queueing network descriptions into transition class models. Transition classes are a highlevel modelling paradigm for the structured and compact definition of Markov chains. Transition class models can be solved with many known solution techniques for Markov chains, exact and approximate, and simulation, even hybr...

in this paper, we consider portfolio selection problem in which security returns are regarded as fuzzy variables rather than random variables. we first introduce a concept of absolute deviation for fuzzy variables and prove some useful properties, which imply that absolute deviation may be used to measure risk well. then we propose two mean-absolute deviation models by defining risk as abs...

As part of the 50th anniversary of the Canadian Operational Research Society, we reviewed queueing applications by Canadian researchers and practitioners. We concentrated on finding real applications, but also considered theoretical contributions to applied areas that have been developed by the authors based on real applications. There were a surprising number of applications, many not well doc...

Within the combinatorial scheduling community, there has been an increasing interest in modelling and solving scheduling problems in dynamic environments. Such problems have also been considered in the field of queueing theory, but very few papers take advantage of developments in both areas, and literature surveys on dynamic scheduling usually make no mention of queueing approaches. In this pa...