A Simple, Practical Prioritization Scheme for a Job Shop Processing Multiple Job Types

The maintenance, repair, and overhaul (MRO) process is used to recondition equipment in the railroad, off-shore drilling, aircraft, and shipping industries. In the typical MRO process, the equipment is disassembled into component parts and these parts are routed to back-shops for repair. Repaired parts are returned for reassembling the equipment. Scheduling the back-shop for smooth flow often requires prioritizing the repair of component parts from different original assemblies at different machines. To enable such prioritization, we model the back-shop as a multi-class queueing network with a ConWIP execution system and introduce a new priority scheme to maximize the system performance. In this scheme, we identify the bottleneck machine based on overall workload and classify machines into two categories: the bottleneck machine and the non-bottleneck machine(s). Assemblies with the lowest cycle time receive the highest priority on the bottleneck machine and the lowest priority on non-bottleneck machine(s). Our experimental results show that this priority scheme increases the system performance by lowering the average cycle times without adversely impacting the total throughput. The contribution of this thesis consists primarily of three parts. First, we develop a simple priority scheme for multi-class, multi-server, ConWIP queueing systems with the disassembly/reassembly feature so that schedulers for a job-shop environment would be able to know which part should be given priority, in what order and where. Next, we provide an exact analytical solution to a two-class, two-server closed queueing model with mixed non-preemptive priority scheme. The queueing network model we study has not been analyzed in the literature, and there are no existing models that address the underlying problem of deciding prioritization by job types to maximize the system performance. Finally, we explore conditions under which the non-preemptive priority discipline can be approximated by a preemptive priority discipline

A New Framework Supporting the Bottleneck Analysis of Multiclass Queueing Networks

none2J.ANSELMI; P. CREMONESIAnselmi, Jonatha; Cremonesi, Paol

Performance evaluation methodologies and tools : selected papers from VALUETOOLS 2008

International audienceThis Special Issue of Performance Evaluation Journal is a selection of nine high-ranked papers from the third edition of the International Conference on Performance Evaluation Methodologies and Tools (Valuetools'2008) that was held on October 20-24, 2008, in Athens, Greece. The aim of the Valuetools conference series is to enable and strengthen scientific exchange and cooperation between disparate research communities involved in the performance evaluation of computer, communication and service systems, and to promote the interdisciplinary flow of technical information among industry systems designers and researchers. Valuetools'2008 was composed of a general track and four associated workshops: Gamecomm'08 (The 2nd ICST/ACM International Workshop on Game Theory in Communication Networks), SMCTools'08 (The 3rd International Workshop on Tools for solving Structured Markov Chains), Inter-Perf'08 (Workshop on Interdisciplinary Systems Approach in Performance Evaluation and Design of Computer & Communication Systems) and WNS2'08 (The Second Workshop on NS-2). Of the nine papers selected for this special issue, eight came from the conference general track and one from the associated workshop Inter-Perf. All the selected papers received excellent reviews for their conference version. These papers were revised and extended to meet the journal standards, and their journal version was peer-reviewed for this Special Issue by three reviewers. The included papers, whose topics range from queuing theory to wireless networks analysis and control, are: * Yoni Nazarathy and Gideon Weiss. Positive Harris Recurrence and Diffusion Scale Analysis of a Push Pull Queueing Network; - Jonatha Anselmi and Paolo Cremonesi. A New Framework Supporting the Bottleneck Analysis of Multiclass Queueing Networks; - David Raz, Hanoch Levy and Benjamin Avi-Itzhak. Class Treatment in Queueing Systems: Discrimination and Fairness Aspects; - Peter Harrison, Naresh Patel and Soraya Zertal. Response Time Distribution of Flash Memory Accesses; Richard Hayden and Jeremy Bradley. Evaluating Fluid Semantics for Passive Stochastic Process Algebra Cooperation; - Iordanis Koutsopoulos and George Iosifidis. Distributed Resource Allocation Algorithms for Peer-to-peer Networks; - Eitan Altman, Tamer Basar, Francesco De Pelligrini. Optimal Monotone Forwarding Policies in Delay Tolerant Mobile Ad-Hoc Networks; - Philippe Godlewski, Masood Maqbool, Marceau Coupechoux and Jean-Marc Kélif. Analytical Evaluation of Various Frequency Reuse Schemes in Cellular OFDMA Networks; - Eitan Altman, Konstantin Avrachenkov and Andrey Garnaev. Fair Resources Allocation in Wireless Networks in the Presence of a Jammer. Together, these papers indeed represent the breadth of tools available for performance evaluation, as well as their various applications