Michio Soshiroda

Comparing integration strategies in production ordering systems

Abstract In this paper, we consider integrating push-type and pull-type production ordering systems and improving the performances of production ordering system for multi-stage production inventory systems. We deal with two strategies for the horizontal integration of push-type and pull-type production ordering systems. Mathematical models of the strategies are constructed, and the performances of the strategies are analyzed mathematically. The standardized variance of production quantity at each production process is considered as the performance criterion for production, and that of inventory level at each inventory point as the performance criterion for inventory. Additionally, in order to select an optimal strategy and to determine the optimal value of the integration parameter, we introduce a total criterion for production and that for inventory, and we analyze the trade-off relationship between the total criteria.

Pull-Push integration in production ordering systems

Abstract In this paper, we study Pull-Push integration in production ordering for multistage production inventory systems. In Pull-Push integration, the succeeding stages are ordered by a pull-type production ordering system and the other stages are ordered by a push-type production ordering system. After reviewing the previous literature, we develop a mathematical model of an integrated production ordering system. As performance measures, we analyzed the amplifications of production quantities and inventory levels, and we show that the proposed production ordering system makes the performance of preceding stages much better than a pure push-type or pull-type production ordering system.

Flexibility of production ordering systems

The flexibility of production ordering systems as medium range production control systems are studied. The changes affecting flexibility, production ordering systems as responses to changes, and the performance measures of flexibility are clarified. On the basis of this framework, mathematical models of production system and production ordering systems are developed to evaluate their flexibility. Two types of changes are considered: demand fluctuation and downtime fluctuation due to machine breakdown, and two models for ‘push-type’ and ‘pull-type’ production ordering systems are investigated. By simulating the models, the amplifications of production quantities and inventory levels as flexibility measures for each type of production ordering system are analysed and the flexibility compared.

Designing an effective production system for processing agricultural products

This paper deals with the problem of designing an effective production system for processing agricultural products, where raw materials, are harvested seasonally and have a limited shelf-life because of their perishability, although the market demand for the final products may be reasonably uniform throughout the year This model can clarify the relationship between production capacity and supply capability to the annual market demand, where the production system has two different types of processing processes and the number of workers hired by the plant is constant throughout the year. From the results of analysis, this paper proposes a method for designing an optimum production system under multiple-objective functions.

Conference paper. A production model for agricultural processing products

This paper deals with the problem in designing an efficient production system where perishable raw materials are to be professed into several kinds of end-products. This model can clarify the relationship between the production capacity and the buffer inventory of end-products that are able to control, within their acceptable limits, both the decaying loss of harvested raw materials and the out-of-stock level of end-products.

Estimating inventory variance with the batch means method

Abstract This paper presents a simulation experiment and an estimation method to analyze the inventory variance of a production-inventory system with production capacity constraint. We first construct a model of the production-inventory system with production capacity constraint. Next we clarify the problems of estimating inventory variance and propose an estimation method with applying the batch means method to the problems. Furthermore, comparing the proposed method with a previous method developed by Welch, we quantitatively evaluate the performances of the methods. As results, we clarified that the problems of autocorrelation and non-normality of the inventory variances time series occur as the production capacity constraint becomes tight. In spite of the problems, the estimation method proposed in this paper can estimate inventory variance with satisfying the required confidence level. The Welch method can estimate inventory variance too, however, the proposed method is more suitable to this problem because the length of confidence interval is shorter than that of Welchs method.

Effect of factory automation on worker's desires in manufacturing industry

This paper deals with a problem to develop ‘factory automation systems’ which harmonize companies’ needs with workers’ desires. Two kinds of indices and methods of survey are proposed on the basis of the ‘fusion system concept’. One is that of the state of workers’ desires which are based on the ‘stimulus-response model’, the other is that of situations where ‘factory automation’ is implemented in a workshop. The effects of ‘factory automation’ on workers’ desires are clarified in a study of Japanese manufacturing industries in 1983. As a result of this investigation, some problems can be pointed out which should be solved in the future to develop ‘factory automation systems’.

Production system for the agricultural processing industry

SUMMARY This paper deals with designing an optimum production system for the agricultural processing industry, where raw materials are harvested seasonally and are usable for only a limited shelf-life First discussing the supply capability for the annual market demand, this model clarifies the relationship of production capacity consistent with average stock level of end-products and storage capacity of holding semi-products (half-processed products).

Scheduling procedures for special order items in a two-stage lot production system

In a two-stage lot production system, even in a pure flow-type, it is inevitable that idle periods arise at either stage because of the differences in set-up times, processing times, or lot sizes of items produced. The duration and location of idle periods on a repetitive production line could be modified by the number of set-ups or the sequence in a production run. The character of the two-stage lot production system makes it difficult to schedule optimal plans for certain values of system parameters, such as the lot sizes of items, waiting times between stages, and the utilization of each stage. Two kinds of items are introduced: one is ‘standard items’ under the assumptions of a constant usage rate, and production in both stages, and the other is ‘special order items’, stochastic demand at unpredictable intervals and production in either stage. Analytic formulations are made on the duration and location of idle periods, and relationships between the characteristics of the special order items and the id...

Estimating a percentile from autocorrelated simulation outputs

Abstract In this paper, we study the estimation of a percentile from autocorrelated simulation outputs. After reviewing the literature on percentile estimation, we propose an estimation method based on the batch means method. By means of experimental investigations for the several methods, it is shown that the proposed method is more efficient than the previous methods.