An Optimum Repair Policy for the Machine Interference Problem

This paper presents two repair policies for the machine interference problem where machines have two failure modes. In policy I priority of repair is assigned to one failure mode over the other, while in policy II the two failure modes have equal probability of repair. Computer programs were developed to obtain the optimal number of machines to be allocated to a single repair crew for the two policies. Under the same operating conditions, policy II is superior to policy I. The repair crew efficiency and machine availability were evaluated for both policies.     

Optimum Ordering Policy for a Multi Item Single Supplier System

An algorithm is presented in this paper for determining the optimum ordering policy in a situation where a number of items are supplied by a single supplier. A problem involving 15 items, which are supplied by a single supplier, is solved for illustrating the recommended procedure.     

A Production Lot-Size Model for Perishable Items Under Two Level Trade Credit Policy for a Retailer with a Powerful Position in a Supply Chain System

This paper investigates a production lot-size inventory model for perishable items under two levels of trade credit for a retailer to reflect the supply chain management situation. We assume that the retailer maintains a powerful position and can obtain full trade credit offered by supplier yet retailer just offers the partial trade credit to customers. Under these conditions, retailer can obtain the most benefits. Then, we investigate the retailer’s inventory policy as a cost minimization problem to determine the retailer’s inventory policy. A rigorous mathematical analysis is used to prove that the annual total variable cost for the retailer is convex, that is, unique and global-optimal solution exists. Mathematical theorems are developed to efficiently determine the optimal ordering policies for the retailer. The results in this paper generalize some already published results. Finally, numerical examples are given to illustrate the theorems and obtain a lot of managerial phenomena.     

The Determination of the Optimum Joint Replenishment Policy for a Group of Discount-Connected Stock Lines

This paper investigates the situation where a joint replenishment order for a group of stock lines from a common supplier qualifies for a quantity discount provided the total order equals a specified number of units. It is assumed that, when any line in the group reaches its reorder point, an order of this size is made for the whole group and it is the problem of how to determine the optimum order "mix" which is considered here. In the case of a group consisting of two lines only, an analytical solution is derived which, assuming Poisson sales-rates, gives the individual stock levels for which the expected number of sales between successive replenishments is maximized for a given total stock. However, for groups of more than two lines, it was necessary to resort to numerical methods and a computer program is described which uses a quasi dynamic-programming approach to determine the optimum set of individual stocks for any given set of sales-rates and total stock. Based on the results from this program, a "ready reckoner" has been constructed which permits an easy look-up to obtain the optimum allocation of any given total stock between the lines of a group of any size and sales-rates. Finally, the possible extension of this approach to other multi-item inventory problems is discussed.