With failures of dual stages of progress to complete failure from potential failure taken into account, reliability analysis is made in this paper with dual stage control method of making repair of failures as classified into two stages and preventive maintenance. Especially, repair is not immediately made on ocurrence of a failure, the waiting time for repair caused on extreme drop in the availability of the system. We successfully analyzed reliavility for a one-unit system under some suitable assumptions using Markov renewal process. Finally we show some numerical examples as the availability.

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This paper deals with 2-stage tandem-type fixed-term reordering system which can be a very fundamental model of multi-stage inventory system, and compares following three control methods : 1. The method controlling each stage independently. In this method, information of market demand is used in order to control only the nearest stage by the market. 2.The method of using information of market demand to control each stage. This method is of J.F. Magee's suggestion. 3. The method of mixing former two methods. Main results are that term-end inventory variance of Magee's method is less than that of independently controlled method, and there should be more advantages by mixing two methods.

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In this paper, the analysis of the random character in stock market prices was performed. Firstly, the mechanism of variations in stock prices was considered as a feedback system which consisted of stock prices as andogenous variables and peculiar noises as exogenous variables. Then, impulse response functions and relative power contributions were estimated by using the method of system identification through the multiple autoregressive model and interactions among stock prices were investigated. The results of the analysis for stock prices of three beer companies in Japan showed good agreement with the actual situation. Consequently, it was found that modeling the mechanism of variations in stock prices as a feedback system was effective.

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This paper discussesa design of production planning rule for the type of system in which raw materials are suppleid mostly seasonally and which has a limited shelf life. On the other hand, demand for the products is almost constant through the year. It is proposed that the size of work force gives a measure of production activities. We introduced a control variable which coordinated between the production quantities of the final and intermediate products in the season of raw material's supply. The derived production planning rule is able to minimize the obfective function.

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One of the most important problems of scheduling system in job shop environment lies in the difficulty of estimating the reasonable manufacturing lead time. The shop time has influences on the manufacturing lead time. Accordingly, it is necessary, as the groundwork of lead time estimation, to investigate the relations between the shop time and the factors giving influences on it and to make the behaviors of shop time clear. The shop time consists of five elements. Among them, the queue time cannot be estimated so easily as others. In this paper, new estimate equation of mean queue time is developed.

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The purpose of this paper is to present an approximation method, called"Space Method"that can be used to find an optimal subset under multiple constraints from a proposed compound set of altermatives in which there exist mutually exclusive or independent relationships. Two algorithms for finding approximate solution are discussed and some numerical experiments are designed to investigate the properties of our algorithms.

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In this paper, we deal with economic analysis of the multiproduct production system by using break-even analysis. Considering semi-variable costs which depend on the production volume and the operation planning, we formulate the problem of obtaining the optimum operation planning and propose reccurence relations of dynamic programming under the consideration of seasonal demand of each product. Also the mathematical relationship between the production volume(man-hours required)and profits is specified for each alternative of product-mex, and the economic product-mex policy which maximizes profits is proposed. Finally a numerical example is presented to explain the procedure proposed.

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In the previous papers, methods were proposed for determining a sample-size to minimize the expected costs for single-operator and multi-operator production systems. This paper gives a computational procedure for calculating the cost factors to show the applicabillity of proposed methods. The numerical examples of the cost factors production system design(c_1,c_2), production system operation(c_3,c_4)and work measurement (c_5) are investigated in practical factories, then a basis for the determination of sample-size is provided.

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The pupose of this study is to find out the physical indicator which manifests the characters of the clerical work, as the numerical value using for quantitative analysis of the office work. From the preliminary and principal experiments in which 26 subjects were used and the results of their analysis, it has been concluded that the coefficient value of the deviation of the heart rates is more useful on this study as the physical indicator than the mean value of the heart rates.

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This paper describes the result of an experimental study on a comparison of a new designed job enlargement system with a conventional conveyer system in a practical workshop, where the same workers were used as the common subjects working in both systems. It became clear through the experiment that both the productivity and steady CFF level were higher in the job enlargement system than that of the another. It was confimed that the workers behave more freely during working time in the new system than in the another one. Under the conditions mentioned above, it is clear from this study that the job enlargement system is relatively superior to the conveyer system in tems of the work-load and productivity.

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For a non-normal quality characteristic X, the sampling inspection plans are sometimes chosen from the plans based on the nomal distribution, or derived from approximating the X^^-'s distribution by the normal. In this paper, the effects of these normal approximations on characteristics of the plans for varizbles sampling inspection are evaluted by the aid of the Fisher and Comish's asymptotic expansion. The effects are measured by the differences of the producer's and the consumer's risks from the specified values. Then, it is shown that these risks greatly differ from the specified values when the X's distribution is regarded as the normal, and that on the other hand, the approximation is quite good when the plans are derived from the normal approximation to X^^-'s distribution.

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Multiple regression analysis based on the least-squares method gives a quantitative relation between objective variable and several explanatory variables. The regression coefficients obtained by the least-squares method, however, are not necessarily of practical use. This paper presents a suggested application of linked vector pattern to the multiple regression analysis. The use of the recommended technique insists that the sign of regression cofficients derived from the method are significant and the regression equation represents the high degree of correlation . Several numerical examples are also given.

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In the prefabricated concrete panel production of the housing industry, both the panels of a special item ordered by a customer and a standard item are produced through the same process, where each metal from is required to produce a panel each. The former cannot be produced until the order arrives, while the latter is produced with the forecasting infrmation. In this paper, we analuyze experimentally the relations between the parameter indications the number of available forms for standard item and the average utilization of the form for standard item, the average process utilization and the average and the standard deviation of the shop time under the conditions of some load ratios and the ratios indicating the quantity of the standard item per order.

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This study shows hypothetically the existence of perception factors and product factors on consumers' quality expectations and experimentally verifies these factors. Perception factors represent consumers' point of views common to products and product factors characterize each product property. From the survey on functional characteristics of 21 durable consumer goods, five perception factors and three products factors are obtained. Further the difference of consumers' expectations for product categories is quantified based on the relation of both factors and one method to make policy of product quality is shown with these results.

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