Haruo Miyazaki

A Successful Application of Job Enlargement/Enrichment at Toyota

Abstract When designing a production system to meet the company desires, the desire of the workers should also be considered. A survey at the Toyota Tsutsumi plant indicated that workers wanted enlarged/enriched jobs. The jobs were enlarged/enriched through a system of cross-training and job rotation. Productivity and quality were improved.

Lattice path counting and M/M/c queueing systems

We apply the lattice path counting method to the analysis of the transientM/M/c queueing system. A closed-form solution is obtained for the probability of exactlyi arrivals andj departures within a time interval of lengtht in anM/M/c queueing system that is empty at the initial time. The derivation of the probability is based on the counting of paths from the origin to(i,j) on thexy-plane, that have exactly rd x-steps whose depth from the liney=x isd (d=0,1,...,c−1). The closed-form solution has an expression useful for numerical calculation.

A new approach to production systems through developing human factors in Japan

Abstract Under the present labour conditions of Japanese industry, this study takes as its goal the development of new production systems which have a high rate of production efficiency through heightening awareness of human factors. Furthermore, this report presents new methodology and a number of models which analyse the relationship between motivation and those various factors of production systems which influence motivation. This paper discusses the findings of the investigations of typical Japanese enterprises using this method.

An approach to the design of production systems giving a high quality of working life and production efficiency

Peoples social and economic desires are gradually becoming more versatile and fragmented. Industries should be developed in such a way that these versatile human desires are brought into harmony with the organizational needs of production engineering. In this paper we report on the state of the desires and motivations of Japanese workers in 1974 and 1977 resulting from investigation and analysis using application methods of multivariate analysis and give an example of new production systems in which workers are in harmony with organizational needs.

Selection of inspector for visual inspection

SUMMARY This paper presents a statistical method for selecting the best inspector for visual inspection having the highest defect-finding ability among k(≥2) prospective inspectors. A sample containing known number of defects are submitted to each of k prospective inspectors. As the sample size is increased, sampling variation decreases so that we have a better chance of selecting the truly best inspector, but at the same time the cost of sampling is also increased, The problem is how to determine the sample size required for selecting the best inspector with specified probability P*. This problem is formulated from the indifference zone point of view with an application of the loss function which takes into consideration the opportunity cost of making a wrong selection and the cost of sampling. Minimax solution is obtained under the restriction that the best inspector is to be selected with the specified probability P*. The selection procedure is applied to the visual inspection of car body painting.

Generation of interpolation curves with the least energy using dynamic programming

Abstract In shape construction, it is often required for a curve to interpolate smoothly among given points and to be compatible with physical phenomena. A curve with the minimum strain energy is known as a smooth curve satisfying those requirements. Some interpolation methods have been developed to approximate the strain energy in a suitable way and to generate a curve for which the approximated strain energy is minimum. Nevertheless, generated curves sometimes contain “wiggles” or “bumps”. The purpose of this paper is to solve directly an equation to construct the C (1) piecewise curve with the minimum strain energy and to generate the curve with little “wiggles” or “bumps”. For this purpose, the optimality equation for the minimum strain energy is established by applying dynamic programming to the energy minimization problem. Then, the solution to the optimality equation is obtained by a numerical method and the curve with the minimum energy is generated.

Principal Components and Principal Clusters

Abstract The use of principal components to reduce the number of dimensions so that graphieal representation of the data is possible has been developed. One. of the most important applications is the connexion with cluster analysis. It has not been defined the criteria by which to decide whether there is any justification for dividing a set of observations into clusters. On the whole, we have been obliged to depend on the eye being efficient at this sort of d cision than statistical computation. In this paper, a new method is presented for dividing a set of interdependent random variables into clurters according to the degree of proximity among these random variables and essential principal components, defined by the covariance (or correlation) matrix; a non-linear functional based on the proximity is introduced, whose maximization provides the best division of these variables into cluster. A simple algorithm is proposed for construction of the clustering and also defines a random variable in each cluster...

The Relationship among Workers’ Desires and Design Factors of Production Systems which harmonize Workers’ Desires with Workshop Productivities

We investigated the relationship among workers’ desires and design of production systems for designing production systems which harmonize workers’ desires with company’s need. About 1,500 workers in the Japanese representative manufucturing companies are asked some questionnaires about desires or working life in thier working place. Using their response data and analyzing these data by means of principal components and principal clusteres , workers are mostly classified into two groups in every workers’ desire pattern. These two groups mutually have quite different and interresting characters from the viewpoint of workers’ motivation. More detailed analysis on each group has been developed to abstract some key factors affecting the workers’ motivation from various working environment.

Transient Behavior of the M/M/2/∞/FIFO Queue Starting with Customers

Abstract This paper presents some new perspectives on the time dependent behavior of the M/M/2/∞/FIFO queue. We give the state probability p n (t) of population of size n at time t where the queue starts with any number of customers. Numerical illustrations show how the state probabilities of the queue varies and approaches to steady-state as time evolves.

A Two-Stage Minimax Decision Procedure for Selecting the Best of k Binomial Processes or Populations

Abstract Industrial development planners and decision makers quite often encounter the problem which one of several alternatives (processes, plans, brands, machines, varieties, etc.) is the best. This paper presents a statistical two-stage decision procedure for selecting the best of k (≥2) binomial processes or populations with the highest probability of obtaining a “success” on a single trial. In a first stage, preassigned number of n 1 observations are taken from each of k populations and a subset-selection is made for screening the populations. In the second stage, more n 2 observations are taken from each of the subset selected in the first stage and a final selection is made on the basis of observations obtained in the first and the second stages. The problem is how to determine the subset-selection rule at the first stage and the number of observations n 1 and n 2 required for selecting the best one with a specified probability P*. This problem is formulated from the indifference zone point of view...