Many studies on the location of retail stores have been done in accordance with the "laws of retail gravitation". They are, for example, Huff's formulation and the multiplicative competitive interaction (MCI) model. These studies are mainly concerned with the measurement of the suction force. This paper proposes some fundamental characteristics and a practical algorithm to determine the optimal location which maximize the demand of the store. For this purpose, major assumptions are required as follows : (1) the store deals with the convenience goods, (2) the planning area is one or two dimensional, (3) the suction force is a monotonous decreasing function of the distance from the point of the customer to the store, (4) in case of considering competitors, there exists only one store. Under these conditions the total demand of the store is respectively formulated and the optimal location is discussed. And about 10 fundamental characteristics are clarified. We proposed a practical algorithm to obtain the optimal location. As a result of a numerical example, we show that the characteristics are quite reasonable.
This paper deals with the problem of rescheduling in terms of safety stock, and changed quantity due to rescheduling in a two-stage hybrid flow shop. The first stage comprises one machine in lot production and second stage comprises a number J of machines in continuous production. Three kinds of rescheduling methods are considered : (1)change in sequencing of products to be produced while keeping the production quantity as planned one, (2)change in production quantity, and (3)change in both sequencing and production quantity. Two cases are analyzed that is the rescheduling is conducted for only second stage and for both the first stage and second stage. This paper clarifies the impact of rescheduling system upon the manufacturing performance in a stochastic demand.
Traditional studies concerned with improving the productivity of knowledge intensive workers have run up against how to seek a productivity indicator. In order to solve this problem, this paper approached the question from the perspective that the minimum acceptable productivity point based on self-evaluation of the output of workers is assumed to be the minimum cost, and the break-even point is the minimum acceptable productivity point of management. As a result, a productivity indicator consisted of the evaluation point and the operating ratio of workers. The following standard evaluation method for measuring the productivity indicator has been obtained theoretically. The minimum acceptable point is 60 on a scale of 100,and the average acceptable point is 78. Validity was verified through cross-sectional analysis conducted by a number of project teams in a firm.
Assume that the lot quality characteristics obey N(μ, σ^2). Then, JIS Z 9004 is specified in the case of assuring the fraction defective. On the other hand, Taguchi has presented an approach to quality improvement in which reduction of derivation from the target value is the guiding principle. In this approach the lot quality is evaluated based on a quadratic loss form with respect to the difference between the measured value and the target value of product characteristics. This concept induces us to construct new variable sampling plans based on the Taguchi's quadratic loss function. In this paper, a design procedure of the sampling plans for assuring the loss in the Taguchi's method is proposed. Some numerical results based on the proposed design procedure are illustrated.
This paper discusses how to control the process from which categorical data obtained by inspection distributed as multivariate beta multinomial distribution. In order to control the process, the ⊿^2 Chart is proposed by Takahashi. However many charts are applied as soon as possible in practical process. Then the level of significance of the charts consisted small subgroups must be considered. First of all we discuss the level of significance of the ⊿^2 Chart in case of small number of subgroups and clarify some problems. Next we propose a method to solve the problems. Finally we clarify the level of significance of the ⊿^2 Chart based of proposed method to show this method is useful.
In the construction industry, delivery time of building materials are often delayed according to the pace of construction progress. This causes that extra inventories in building material manufacturers. To minimize the inventories, two production models, i.e., push and pull type production model can be considered widely. When production lead time is short and length of delivery delay is long, pull type may require smaller inventories to keep a certain service level, and push type may require smaller inventories under the condition of longer production lead time and shorter length of delivery delay. To examine performance of average inventory level under different system conditions, factors such as ratio of average length of delivery delay to square root of production lead time, length of production cycle, and coefficient of variation of demand are chosen to define different conditions. As the performance measure, the ratio of push type inventory to pull type inventory (P_<pp>) is used in the comparison of the push and pull type, and a quantitative criterion of production model selection are presented.
It is well known that tool-life is probabilistic in nature and shows considerable variation. Statistical methods based on tool-life distribution for determining the optimum cutting conditions are well recognized, and these methods give more exact analyses of productivity and production cost. To apply these statistical methods to the problem of decreasing production cost or production time, parameters of tool-life distribution should be estimated. This paper presents a statistical tool-life test for estimating the parameters of tool-life distribution.