Journal of the Operations Research Society of Japan
Online ISSN : 2188-8299
Print ISSN : 0453-4514
ISSN-L : 0453-4514
Volume 48, Issue 3
Displaying 1-11 of 11 articles from this issue
  • Article type: Cover
    2005 Volume 48 Issue 3 Pages Cover7-
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
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  • Article type: Appendix
    2005 Volume 48 Issue 3 Pages App5-
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
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  • Yung Fu Huang
    Article type: Article
    2005 Volume 48 Issue 3 Pages 173-182
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    This paper discusses the economic order quantity (EOQ) under partial trade credit. In 1985, Goyal assumed that : (i) The unit selling price and the unit purchasing price were equal. (ii) The supplier would offer the retailer full trade credit under condition of delay payments. The main purpose of this paper wants to modify Goyal's model to presume that the unit selling price and the unit purchasing price are not necessarily equal. Furthermore, in this paper, we assume that the supplier would offer the retailer partial trade credit not full trade credit. That is, the retailer must make a partial payment to the supplier when the order is received. Then, the retailer must pay off the remaining balance at the end of the permissible delay period. Under these conditions, we model the retailer's inventory system as a cost minimization problem to determine the retailer's optimal inventory cycle time and optimal order quantity. One theorem is developed to efficiently determine the optimal inventory policy for the retailer. We deduce some previously published results of other researchers as special cases. Finally, numerical examples are given to illustrate the theorem obtained in this paper.
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  • Takayuki Ishizeki, Hiroki Nakayama, Hiroshi Imai
    Article type: Article
    2005 Volume 48 Issue 3 Pages 183-195
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    To integer programming, algebraic approaches using Grobner bases and standard pairs via toric ideals have been studied in recent years. In this paper, we consider a unimodular case, e.g., network flow problems, which enables us to analyze primal and dual problems in an equal setting. By combining existing results in an algebraic approach, we prove a theorem that the maximum number of dual feasible bases is obtained by computing the normalized volume of the convex hull generated from column vectors of a coefficient matrix in the primal standard form. We apply the theorem, partly with Grobner bases theory, to transportation problems and minimum cost flow problems on acyclic tournament graphs. In consequence, we show new algebraic proofs to the Balinski and Russakoff's result on the dual transportation polytope and Klee and Witzgall's result on the primal transportation polytope. Similarly results for the primal case of acyclic tournament graphs are obtained by using Gelfand, Graev and Postnikov's result for nilpotent hypergeometric functions. We also give a bound of the number of feasible bases for its dual case.
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  • Satoko Mamada, Takeaki Uno, Kazuhisa Makino, Satoru Fujishige
    Article type: Article
    2005 Volume 48 Issue 3 Pages 196-206
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    In this paper, we present a first polynomial time algorithm for the monotone min-max tree partitioning problem and show that the min-max tree partitioning problem is NP-hard if the cost function is not monotone, and that the min-sum tree partitioning problem is NP-hard even if the cost function is monotone. We also consider an evacuation problem in dynamic networks as an application of the tree partitioning problem. The evacuation problem is one of the basic studies on crisis management systems for evacuation guidance of residents against large-scale disasters. We restrict our attention to tree networks and consider flows such that all the supplies going through a common vertex are sent out through a single arc incident to it, since one of the ideal evacuation plans makes everyone to be evacuated fairly and without confusion.
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  • Ramon Martin Rodriguez Dagnino, Hideaki Takagi
    Article type: Article
    2005 Volume 48 Issue 3 Pages 207-225
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    Knowing the distribution of the number of handovers during a call session of a given user is particularly important in cellular mobile communication networks in order to make appropriate dimensioning of virtual circuits for wireless cells. In this paper, we study the probability distributions and statistical moments for the number of handovers per call for a variety of combinations of the call holding time (CHT) and cell residence time (CRT) distributions. We assume that the first CRT in the originating cell has different statistics from the CRTs in the subsequent cells. In particular, we consider circular cells. Based on the formulation in terms of delayed renewal processes, we obtain analytical expressions for the probability mass functions and moments of the handover number distribution. We also include some numerical results for the mean number of handovers.
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  • Tetsuji Hirayama
    Article type: Article
    2005 Volume 48 Issue 3 Pages 226-255
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    We consider polling systems in which a single server visits stations in cyclic order and serves customers at each station according to either the gated rule or the exhaustive rule of the station. There are multiple classes of customers at each station, and they are served in either the priority order or the first-come-first-served (FCFS) order. After completing a service at a station, each customer may be routed to one of the stations or leave the system according to the Markovian feedback mechanism. In this paper, a new approach to mean sojourn times in multiclass queues, developed in [11, 14, 15], is extended to the feedback polling systems as follows. We define the conditional expected sojourn times and find their linear functional expressions by solving some equations. The steady state average sojourn times are derived from these expressions by simple limiting procedures, and their values are obtained by solving a set of linear equations. We also consider composite scheduling algorithms and calculate mean path times.
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  • Toshio Hamada
    Article type: Article
    2005 Volume 48 Issue 3 Pages 256-268
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    The same kind of n jobs are processed one by one sequentially by a single machine and any number k of them may be processed as a batch. A setup time is necessary before the processing of the first job in a batch. The completion times of all the jobs in a batch are the same as the completion time of the last job in the batch and the processing time of the batch is the sum of a setup time and k times of the processing time of a job. The processing time of the job is known, but the setup time is the random variable which is distributed in the gamma distribution with the parameter whose value is unknown a priori. A conjugate prior distribution for the value is considered. The first batch size is decided by using the prior distribution, the setup time is observed, and then the second batch size is decided by using the posterior distribution revised by using the observed value of the setup time in the first batch. This process is repeated until all the jobs have been processed. The objective is to minimize the expected total completion times. This problem is formulated by using dynamic programming and both the several properties derived from the recursive equations and the critical values for the optimal strategy are derived.
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  • Article type: Appendix
    2005 Volume 48 Issue 3 Pages App6-
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    Download PDF (91K)
  • Article type: Cover
    2005 Volume 48 Issue 3 Pages Cover8-
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    Download PDF (32K)
  • Article type: Cover
    2005 Volume 48 Issue 3 Pages Cover9-
    Published: 2005
    Released on J-STAGE: June 27, 2017
    JOURNAL FREE ACCESS
    Download PDF (32K)
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