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Volume 59 (2016)
- Issue 4 Pages 269-
- Issue 3 Pages 225-
- Issue 2 Pages 147-
- Issue 1 Pages 1-
Volume 59, Issue 2
Displaying 1-4 of 4 articles from this issue
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Ken'ichi Katou, Yukio Takahashi2016 Volume 59 Issue 2 Pages 147-173
Published: 2016
Released on J-STAGE: April 25, 2016
JOURNAL FREE ACCESSA new queueing model for customers requesting service positions at a counter is proposed. Each arriving customer requests a service at a particular position, and multiple servers provide services for these customers at their requested positions. The servers can attend different counter positions, but they may not change their order. This model was devised to evaluate the performance of a movable compact shelving system in a recently built university library, and it was used to plan that system. In this paper, we analyze two simple cases, and then some variations of the model are discussed in connection with different service disciplines. The simulation results show some basic properties of the model. We present in some detail the application of our model to a movable compact shelving system.View full abstractDownload PDF (270K) -
Tsuguhito Hirai, Hiroyuki Masuyama, Shoji Kasahara, Yutaka Takahashi2016 Volume 59 Issue 2 Pages 174-194
Published: 2016
Released on J-STAGE: April 25, 2016
JOURNAL FREE ACCESSIn cloud computing, a large-scale parallel-distributed processing service is provided in which a huge task is split into a number of subtasks, which are processed independently on a cluster of machines referred to as workers. Those workers that take longer to process their assigned subtasks result in the processing delay of the task (the issue of stragglers). An efficient way to address this issue is for other workers to execute the troubled subtasks for backup purposes (task replication). In this paper, we evaluate the efficiency of task replication from a theoretical point of view. The mean value and standard deviation of the task-processing time are derived approximately using extreme value theory, while the mean total processing time is evaluated exactly, for cases in which the worker-processing time follows a hyper-exponential, Weibull, or Pareto distribution. The numerical results reveal that the efficiency of task replication depends significantly on the tail of the worker-processing time distribution. In addition, the optimal number of replications which achieves the shortest task-processing time mainly depends on the coefficient of variation of the worker-processing time. Furthermore, three replications are effective to guarantee a low variance of the task-processing time, regardless of the tail.View full abstractDownload PDF (319K) -
Ryusuke Hohzaki, Keiich Sunaga2016 Volume 59 Issue 2 Pages 195-217
Published: 2016
Released on J-STAGE: April 25, 2016
JOURNAL FREE ACCESSThis paper deals with two-person zero-sum (TPZS) games in which two players conflict on a network through an attrition phenomenon. The problem has a variety of applications, but we model the problem as a TPZS game with some attrition between attackers and defenders. The attackers start from a starting node and reach a destination node, expecting to keep their initial members intact. The defenders deploy their forces on arcs to intercept the attackers. If the attackers encounter defenders deployed on an arc, the attackers incur casualties proportional to the number of the deployed defenders. We discuss four games where the attackers or the defenders obtain information of their opponent. The games are two-stage games with a common payoff of the number of surviving attackers. We formulate them into linear programming problems to derive their equilibrium points and evaluate the value of the information acquisitioned in the games.View full abstractDownload PDF (200K) -
Hiroshi Hirai2016 Volume 59 Issue 2 Pages 218-223
Published: 2016
Released on J-STAGE: April 25, 2016
JOURNAL FREE ACCESSIn this note, we consider the uncrossing game for a skew-supermodular function f, hich is a two-player game with players, Red and Blue, and abstracts the uncrossing procedure in the cut-covering linear program associated with f. Extending the earlier results by Karzanov for {0,1}-valued skew-supermodular functions, we present an improved polynomial time strategy for Red to win, and give a strongly polynomial time uncrossing procedure for dual solutions of the cut-covering LP as its consequence. We also mention its implication on the optimality of laminar solutions.View full abstractDownload PDF (98K)
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