In making optimal workload allocation to maximize the throughput of an FMS (Flexible Manufacturing System), balancing workload is optimal to the case when each workstation in the FMS consists of the same number of machining centers. Otherwise, unbalanced workload allocation yields the maximum throughput of the FMS. Even in the latter case, the throughput of FMS obtained by balancing workload approaches the optimal value given by the optimal, unbalanced workload allocation as the number of pallets increases. The minimal number of pallets is, therefore, presented so that the relative deviation of the throughput value obtained by balancing workload from the optimal value is smaller than 3% or 5%. Approximate equations are derived to get the near-optimal workload allocation with high accuracy when the number of pallets is not larger than the minimal value.

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In multiobjective scheduling problems, a preferred schedule is determined from a set of nondominated schedules. However, due to the combinatorial nature of scheduling problems, it is very hard to efficiently generate all of the nondominated schedules. In this paper, an interactive approach for searching a preferred solution using a "revised complex random sample scheduling method (CRSS)" is proposed for efficiently finding a preferred schedule. Exploiting preference information given by a decision maker, the revised CRSS generates a reduced set of nondominated schedules neighboring a preferred schedule. The results of some numerical experiments are shown to demonstrate the efficiency and accuracy of this method.

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Recently, we have presented a design procedure for the rectifying attribute sequential inspection plans indexed by lot tolerance percent defective (LTPD), by applying the sequential sampling plans with given producer's and consumer's risks based on the minimal lattice paths (MLP) proposed by Furukawa, Ohta and Kase. In this paper, we present a design procedure for the new rectifying attribute sequential inspection plans indexed by average outgoing quality limit (AOQL). Through the numerical results, it is shown that the proposed rectifying sequential inspection plans indexed by AOQL are more profitable from the viewpoint of the average total inspection than the rectifying single inspection plans indexed by AOQL.

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A full functional flexible manufacturing system (FMS), in which each machine has all of the tools required for processing various kinds of jobs, is superfluous and wasteful in meeting changeable, multiform demands in a flexible manner. To reduce the redundancy, a completely separated functional FMS having no duplicated tools, and a partly separated functional FMS having some duplicated tools are introduced in this study. We propose the methods for distributing tools to each machine in an openshop-type FMS and a jobshop-type FMS to meet demands and maximize the utilization of the FMS. Some simulation results demonstrate the effectiveness of the proposed methods for increasing the utilization of the FMS.

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We propose a method for solving 0-1 linear programming problems with both generalized upper bounding (GUB) structures and interval coefficients without transforming them into crisp problems, keeping coefficients as intervals on the process of the calculation. In this method, we define the degree of satisfying the inequality relationship between intervals with minimal loss of fuzzy information. The proposed method is utilized for optimization of system reliability with fuzzy state to present an approximate solution and the interval objective function value. To demonstrate the effectiveness, a numerical example is shown and compared with conventional methods.

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In the (x^^-, s) simultaneous control chart, a pair of sample mean and standard deviation is expressed as a point (x^^-, s) on a rectangular-coordinate graph. The user of the (x^^-, s) simultaneous control chart can easily find a change of process state since the state of a process can be visually grasped by this chart. In this paper, we propose a new design procedure for the control limits of the (x^^-, S) simultaneous control chart by measuring distance between a distribution of the stable state and an estimated distribution of the present state using the Kullback-Leibler information. The distribution of the information amount is effectively given by the Patnaik's chi-square approximation. Using this approximation, the (x^^-, s) simultaneous control chart can be designed by specifying the probability of the Type I error.

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This paper investigates the problem of obtaining an optimal production sequence and lot collecting policy to minimize transportation frequency of items between machines in a two-stage flow shop setting. The problem is described on a cumulative domain whose horizontal axis represents time and vertical axis refers to the cumulative number of items, and the optimal lot collecting policy and the "dominance" condition on a processing time of each item on the machines are clarified. In the case in which any pair of items satisfy the dominance condition, an optimal sequence is obtained according to the ratio of processing times of items between the two machines. These results are applied to the problem of dividing a large number of order lot sizes for multiple products into unit lot sizes for processing and transporting.

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In this paper we discuss the optimal pricing for new multiattribute products based on the utility values of attribute levels measured by the conjoint analysis. The conjoint analysis has been widely accepted as a procedure for measuring consumers' trade offs among multiattribute products. In the conjoint analysis, by applying the Johnson's trade-off approach to the rank orders data of preference among pairs of attributes (that is, profiles) obtained from consumers, the utility value for each attribute level is estimated. In this case a heuristic algorithm is proposed which attains the reproducibility of the rank orders of preference among pairs of attributes.

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The problem of obtaining the most economical timing for the replacement of an equipment currently under utilization which a new one under like-for-like replacement, is composed of those to determined the economic life of the new equipment and to determine the replacement timing from the current equipment to the new one. Both of these determinations are dependent on the value of the capital interest rate. This paper analyzes the effect of value of the interest rate upon the economic life and the replacement timing, and clarifies that the values of interest rate, which work as breaking points both in economic life and replacement timing determination, can be obtained by a simple procedure as an internal rate of return for a simple cash flow pattern. Based on these results, a solution method applying the internal rate of return to the equipment replacement problem is derived and presented.

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In system design, what items can be regarded as what type of system characteristics depends on the unique purpose and situation of the system, i.e.the system specification, and therefore can not be generalized. However, the freedom of design is enhanced in Work Design, or, as Dr.Nadler now calls it breakthrough thinking, the inputs and methods for transforming inputs into outputs or catalysts can be chosen freely in order to pursue ideal systems. In such a case, there sometimes occurs a confusion as to whether a factor is an input or a physical catalyst mentioned in this paper. Inputs and catalysts in Work Design have not been defined completely. For example, when a system to cool orange juice has to be designed, is ice dealt with an input or a catalyst? Ice is usually put into juice. Some people drink ice with juice. Therefore, many system designers often think that ice is an input. But if ice is dealt with as an input, there is no room for devising methods except ice. In this paper, it is discussed that ice has to be dealt with as a catalyst, that inputs and catalysts are newly defined, and that a sub-procedure is proposed to design portions of a system in the case where such a confusion between input and catalyst has occurred.

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