Asia-Pacific Journal of Operational Research

In this article, we study nonsmooth convex minimax programming problems with cone constraint and abstract constraint. Our aim is to develop sequential Lagrange multiplier rules for this class of problems in the absence of any constraint qualification. These rules are obtained in terms of ∊-subdifferentials of the functions. As an application of these rules, a sequential dual is proposed and sequential duality results are presented.

Recently a new least-squares primal-dual (LSPD) algorithm, that is impervious to degeneracy, has effectively been applied to solving linear programming problems by Barnes et al., 2002. In this paper, we show an application of LSPD to shortest path problems with nonnegative arc length is equivalent to the Dijkstra's algorithm. We also compare the LSPD algorithm with the conventional primal-dual algorithm in solving shortest path problems and show their difference due to degeneracy in solving the 1-1 shortest path problems.

According to the marketing principle, a decision maker may control demand rate through selling price and the unit facility cost of promoting transaction. In fact, the upper bound of willing-to-pay price and the transaction cost probably depend upon the subjective judgment of individual consumer in purchasing merchandise. This study therefore attempts to construct a bivariate distribution function to simultaneously incorporate the willing-to-pay price and the transaction cost into the classical economic order quantity (EOQ) model. Through the manipulation of the constructed bivariate distribution function, the demand function faced by the supplier can be expressed as a concrete form. The proposed mathematical model mainly concerns how to determine the initial inventory level for each business cycle, so that the profit per unit time is maximized by means of the selling price and the unit-transaction cost to control the selling rate. Furthermore, the sensitivity analysis of optimal solution is performed and the implication of this extended inventory model is also discussed.

In this paper, we consider the single machine scheduling problem with linear earliness and quadratic tardiness costs, and no machine idle time. We propose a lower bounding procedure based on the relaxation of the jobs' completion times. Optimal branch-and-bound algorithms are then presented. These algorithms incorporate the proposed lower bound, as well as an insertion-based dominance test.

The branch-and-bound procedures are tested on a wide set of randomly generated problems. The computational results show that the branch-and-bound algorithms are capable of optimally solving, within reasonable computation times, instances with up to 20 jobs.

This research analyzes a kitting system where multiple components are grouped to form a predefined kit prior to assembly. The kitting system is modeled as a fork/join synchronization station and component supply is assumed to be from fabrication facilities operating under a kanban control policy. Exact analysis of these systems is computationally intensive even under Markovian assumptions. To evaluate the impact of input parameters on kitting system performance, several easily computable bounds on system throughput are first identified. Using these bounds, closed form approximate expressions for system throughput are derived. The throughput estimate is used to compute other performance measures of interest such as mean queue length and mean waiting time in the system. The accuracy of the approximations is validated using numerical experiments and some performance insights are given.

This paper evaluates the distribution of papers published by Asian authors in Operations Research and Management Science (OR/MS) journals from 1968 to 2006. The impact of OR/MS research in Asia is compared with that of the United States and the World, and research trends are highlighted through an analysis of keywords. From 1968 to 2006, 89,293 papers were published in 60 OR/MS journals. Of these, 41.4% came from USA and 16.6% came from seven Asian countries/regions. The contribution of different countries/regions is as follows: Japan 3.7%, Taiwan 3.2%, India 2.3%, Hong Kong 2.2%, South Korea 2.1%, People's Republic of China (PRC) 1.9%, and Singapore 1.2%. Among all the articles analyzed, 20% have a single author, and 9% have more than three authors; additionally, 22 papers have been cited more than 100 times and 29% have never been cited. Most articles originating in Japan, Taiwan, India, South Korea, PRC, and Singapore are produced in collaboration with local scholars, followed by authors from the United States. Hong Kong is a notable exception, 73% of articles from Hong Kong are produced in cooperation with the PRC, followed by local scholars. The five most productive institutions are as follows: The Indian Institute of Technology, the Korea Advanced Institute of Science and Technology, the National University of Singapore, The Hong Kong Polytechnic University, and the National Chiao-Tung University (Taiwan).

In this paper, an optimization model with a linear objective function subject to a system of fuzzy relation equations, using max-Hamacher product composition operator, is presented. Since its nonempty feasible solution set is in general a nonconvex set, conventional linear programming methods are not suitable to solve such a problem, so an efficient solution procedure for such problems is necessary. In this paper, the feasible solution set of this problem is studied at first. Then, one efficient algorithm (i.e. tabular method algorithm) is proposed in order to solve the problem. Some procedures are also presented to reduce the original problem. Then, the reduced problem is decomposed (if possible) into several sub-problems with smaller dimensions, so solving them becomes very easier by the algorithm. By combining the algorithm and these procedures, another more efficient algorithm is suggested in order to obtain the optimal solution of the original problem. Some numerical examples are also given to illustrate the algorithms.

In today's business environment, a supplier usually offers customers a permissible delay for settling outstanding account balance for the goods supplied. However, a supplier on occasion may allow this permissible delay in payments to be more than the usual during a given specified period. In this paper, we establish an appropriate model for a customer to determine its optimal special order quantity when the supplier offers a special extended permissible delay for one time only during a specified period. We then establish two theorems for a customer to find the optimal special order quantity. Finally, several numerical examples are given to illustrate the theoretical results.