Yorimasa Kuba

On the optimal number of machines operated by a single worker

Abstract An optimal design problem is considered for man-machine systems, where a group of numerically controlled (NC) machines is operated by a single worker. The processing time at each machine and the service time by the worker are assumed to be random variables. The decision variable is the number of machines in the group and the optimal criterion is to minimize the cost for producing a product. It is found that the minimum-cost number of machines, N c , is the lower bound on the optimal numbers of machines under other important criteria. We present the upper and lower bounds on N c s for the systems where the coefficients of variations of the service- and processing-time distributions are less than 1. Moreover, it is shown that the bounds are tight for such systems.

An educational system of the information processing using the database on personal computer

Abstract The present paper describes a educational system in the information processing using the relational database. The target in this system is the construction of a self-teaching system of the way to handle coding errors. Personal data and the information to correct coding errors are managed in the system. The attempt is discussed in which beginners efficiently learn programming skills up to eliminating translation errors by correcting errors using the system. Using the relational database has the validity in the usability for beginners and the facilitation of the security protection on personal information.