We analyze the transient behavior of the PH/M/S/K queue. Emphasis is placed on the overflow process, busy period distribution, idle period distribution, accepted arrival process, departure process and the transition probabilities of the system states. All results are represented by the addition and multiplication of the matrices whose dimensions are at most equal to the number of phases for the inter-arrival time distribution.

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We consider the problem of minimizing the long-run average expected cost per unit time in a semi-Markov decision process with arbitrary state and action space. Using the idea of successive approximations, sufficient conditions for the existence of an optimal stationary policy are given. These results are applied to solve the replacement problem with a semi-Markov shock model.

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It is a very atractive feature of ISM that it activates subjective judgments for problem solving. But this feature becomes a restraint of ISM in practical situations, because we need a guarantee of the "objectivity" of the result at the implementation stage. In this paper, we pick up the problem of evaluation of the safety of evacuation routes in great quakes, in which we need to use our subjective judgment, and we discuss the potential for certain guarantee of the "objectivity" of the subjective result supported by ISM. Each evacuation route is characterized by several components which prescribe its safety level in a strong quake. We determine seven such dominant components, applying ISM in the usual way. And we prepare so-called "characteristic cards", in which these seven components are described according to preevaluation using individual evaluation models. Next, we propose a subjective evaluation system supported by ISM to synthesize these components and to do comprehensive evaluation. This system requires only relative evaluation and not an absolute one. That is, an evaluator is only responsible for the pair-wise comparison of safety between two routes using two cards. The result of subjective evaluation is imbedded in a binary matrix, and transformed by the structuralization algorithm of ISM into a multi-level diagraph that shows a safety order of sample evacuation routes. In practice we use VISMS, developed by the author as an expanded computer system of ISM, and demonstrate how to develop the "safety-order diagram" The process supported by VISMS is highly visible so that other people can follow its development very easily and check up on the result from their own points of view. This feature is one important condition for a guarantee of objectivity of the subjective result. Finally, we try to check the possibility of a numerical explanation of the the result as another condition for a guarantee of objectivity. Here we classify the sample routes into three categories; safe, moderate, and danger, according to the subjective evaluation, and we apply Discriminant Model and reclassify them according to this numerical model. In this research we can show that the gap between the subjective judgment and the numerical classification is found only in two cases among twenty-four samples.

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N independent and identically distributed observations of some random variable with a continuous distribution F are sequentially presented to two players, White and Black. Each player is required to select exactly one observation without recall to rejected observations. As long as both players have not made a selection, White is always given the first option to accept or reject an observation. Both players are given the same information and are aware of the selection made by the other player. The player selecting the largest number wins the game. This problem is considered for the two cases, when either F is known or unknown. The probability of each player winning and the distribution of the location in the sample where selections are made is obtained. Also asymptotic results are derived. The problem is couched in terms of a horse bet.

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This paper is to report on an empirical study on the importance of the communicational role of the team leaders in multi-departmental OR/MS projects. It also considers the influence of a project characteristic in terms of the degree of innovativeness and the roles being played by the managers of concerned departments. In order to measure the degree of communication role a sociometric method was used. It was found that in multi-departmental OR/MS projects, the presence of managers who act as communication centers among departments plays a vital role in their success. Especially when a project is oriented toward innovative type, the role of a team leader at higher rank becomes very important.

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