Phone: (360) 650-2867 Fax: (360) 650-4844 Office: Parks Hall 335
E-mail: george.zhang@wwu.edu
Professor Zhang's research interests include queueing theory and applications, stochastic dynamic programming, probability models in reliability, and supply chain management issues in manufacturing and service organizations. The main theme of his research is to bridge the gap between theory and application, obtaining unobservable and sometimes counter-intuitive but significant/practical management insights via modeling and quantitative analysis.
His papers have appeared or been accepted in journals such as Management Science , Operations Research , Interfaces , Queueing Systems , Journal of Applied Probability , IEEE Transactions , Naval Research Logistics and several other international journals in operations research and applied probability.
Co-authored with N. Tian, his research monograph entitled has been published in 2006 by Springer Science. This is the first book that discusses both single and multiple server queueing systems with vacations. It provides a comprehansive treatment of the extention of the queueing theory. The book contains the updated research results and some practical applications of this class of models.
Professor Zhang is an associate editor of INFOR and is on the editorial board of several international journals.
[To the Top of the page]Forthcoming papers and under revision papers.
" A periodic-replacement model based on cumulative repair-cost limit for a system subjected to shocks. " With Sheu and Lin. Forthcoming on IEEE Transactions on Reliability
" Modeling Security-Check Queues. " With H.P. Luh and C. Wang. in revision (2nd round). Management Science
" Pricing, Capacity, and Financing Decisions in Two-tier Service Systems, " with P. Guo. in revision (2nd round) Management Science
" Information and Pricing in Service Systems with Congestion-Based Staffing Policy. in revision (2nd round), " with P. Guo. in revision (2nd round) Manufacturing & Service Operations Management
Some Representative Publications-Refereed Journal Papers for the period 1993 - present.
" Performance Analysis of a Queue with Congestion-Based Staffing Policy " Management Science , 55 (2), 240-251. February 2009.
" A Risk-Averse Newsvendor Model under CVaR Decision Criterion " with Y. Chen and M. Xu, Operations Research ,57 (4), 1040-1054 (2009)
" Analysis of M/G/1 queue with working vacations - a matrix analytic approach. " with Li, Tian, and Luh Queueing Systems 61 (2-3), 139-166. (2009).
" A note on workload control for an under-utilized server of M/G/1 system " Computers and Industrial Engineering I56, 1, 28-32, (2009).
" A Computational Model for Determining the Optimal Preventive Maintenance Policy with Random Breakdowns and Imperfect Repairs " IEEE Transactions on Reliability with Shirmohammadi, A. 52(2), 332-339. 2007.
" Quantifying the Performance Effects of Utilizing Idle Time in Multi-server Queueing Systems " with N. Tian, Naval Research Logistics Volume 54, 2, Pages 189-199. 2007.
"Extended optimal replacement model of a system subject to shocks ", with Chien and Sheu. European Journal of Operational Research . Volume 175, Issue 1, 16 November 2006, Pages 399-412.
" On the Three Threshold Policy in the Multi-server Queueing System with Vacations, " Queueing Systems Volume 51, Numbers 1-2, 2005, Pages 173 - 186.
" On the Convexity Property of the Two Threshold Policy for M/G/1 Queue with Two Types of Vacations " Operations Research Letters. Volume 34, Issue 4, July 2006, Pages 473-476 .
" The Analysis of Multi-server Queue with single vacation and a (e, d) policy " with Xu Performance Evaluation . Volume 63, Issue 8, August 2006, Pages 825-838
" The Optimal Service Time Allocation of a Versatile Server to Queue Jobs and Stochastically Available Non-Queue Jobs of Different Types " with Love and Song Computers and Operations Research .
" "M/GI/1 models with negative arrivals requesting services", ", with Y Zhu, 41, no. 4 (2004), 1157?170, Journal of Applied Probability .
" A Computational Model for Analyzing the Properties of Stop-Loss, Take-Profit, and Price Breakout Trading Strategies ", with A. Warburton, Computers and Operations Research . Volume 33, Issue 1, 2006, Pages 32-42.
" A note on the GI/M/1 queue with phase-type setup times , ", with N. Tian, Vol 41, 4, November 2003. INFOR .
"The N Threshold Policy for the GI/M/1 Queue ", with N. Tian Vol. 32, 2004, pp. 77-84. Opreations Research Letters .
"Stationary Distributions of GI/M/c Queue with PH type Vacations ", with N. Tian Vol.44, 2, 2003, pp. 183-202. Queueing Systems.
"Analysis of Queueing Systems with Synchronous Single Vacations for Idle Servers ", with N. Tian Vol.45, 2, 2003, pp. 161-175. Queueing Systems.
"The Two Threshold Vacation Policy in Multiserver Queueing System ", with N. Tian. Vol.168, 153-163, 2006. European Journal of Operational Research .
"An Analysis of Queueing Systems with multi-task servers" ", with N. Tian. Vol. 156, 375-389, 2004. European Journal of Operational Research .
"Analysis of Queueing Systems with Synchronous Vacations of Partical Servers ", Vol.52, 2003, pp 269-282. Performance Evaluation.
"Allocating Kanbans for a Production System in a General Configuration with a New Control Strategy ", with Zhao and Nakashima, Vol.32, 3, 2002, pp. 446-452. IEEE Transactions on SMC Part A.
"The Discret-time GI/Geo/1 queue with multiple vacations " with N. Tian, Vol 40, No.3, 2002, pp 283-294 Queueing Systems.
"An Optimal Fixed Maintenance Cycle Policy with Possible Skipping Imminent Preventive Replacements " with A. Shirmohammadi and C.E. Love. Vol. 54, 2003, pp.40-47. Journal of Operational Research Society.
"The Optimal Service Policies in an M/G/1 Queueing System with Multiple Vacation Types " Vol. 39, No.4, 2001, pp 357-366. INFOR.
"Discrete-time Geo/G/1 queue with multiple adaptive vacations " Vol.38, 4, 2001, pp. 419-429. Queueing Systems .
"A Discrete Semi-Markov Decision Model to Determine the Optimal Repair/Replacement Policy Under General Repairs", with C.E. Love, Vol.125, pp.398-409, 2000. European Journal of Operational Research .
"A Simple Recursive Markov Chain Model to Determine the Optimal Replacement Policies Under General Repair ", with C.E. Love, Vol.27, pp. 321-333, 2000 Computers & Operations Research .
"The Threshold Policy in an M/G/1 Queue With an Exceptional First Vacation", with C.E. Love, INFOR Vol. 36, No.4, pp.193-204, 1998.
"An SMDP Approach to Optimal Repair/Replacement Decisions for Systems Experiencing Imperfect Repairs", with C.E. Love and M.A. Zitron. Journal of Quality in Maintainence Engineering Vol. 4, Issue 2, pp. 131-149, 1998.
"Optimal Two-Threshold Policies in an M/G/1 Queue with Two Vacation Types", Performance Evaluation , Vol 29, No.1, Feb. 1997, pp. 63-80. with R.G. Vickson and M.J.A. van Eenige.
"The Cheaper/Faster-Yet-More-Expensive Phenomenon: Are Zangwill's 'Paradoxes' Indeed Paradoxical? ", with Y. Gerchak Interfaces , Vol.24, No.5, (1994), pp. 84--87.
"A Simple Approximation for Mean Waiting Time in M/G/1 Queue with Generalized Vacations and Limited Service Disciplines", with R.G. Vickson Opreations Research Letter , Vol.13, No.1 (1993), pp. 21--26.