Search

A central warehouse supplies two facilities with a product. The facilities are subject in each time period to stochastic demands. The warehouse can allocate stock to the facilities in each period, but can reorder from an exogenous source only after every T periods. Assuming convex holding and shortage costs, linear ordering and allocation costs, backlogging and no transshipment between facilities, the optimal ordering and allocation policies are characterized. It is also shown that after the last ordering instant, the optimal allocation policy reduces to a much simpler form when the costfunctions are separable in their variables, and that results on the zero time lag allocation problem apply to the fixed time lag case when the holding and shortage costs are functions only of the facility inventories and the total system inventory. [ABSTRACT FROM AUTHOR]

A multi product, continuous review inventory model with dependent setup cost is studied and a joint ordering policy is defined. The development of the model is based on the independent (R, Q) policy. A can order point is derived for each product such that if the inventory level of one product drops to its reorder point, all products with inventory level less than or equal to their can order points are ordered together. The analytic results are given for the unit Poisson demands. Simulation experiments are used to compare the joint ordering policy with the independent ordering policy for the case of Stuttering Poisson demands. It is learned that the joint ordering policy achieves a substantial saving in total cost over the independent ordering policy. [ABSTRACT FROM AUTHOR]

The article comments on a paper by Shirley Almon in "Econometrica" about the distributed lag between capital appropriations and expenditures. It reports the results of some experiments conducted using the National Industrial Conference Board's series on capital appropriations and expenditures of manufacturers. It is the same body of data used by Almon in her paper that demonstrated the use of an elegant distributed lag incorporating fixed coefficients. The model used in the experiments incorporates a variable lag between appropriations and expenditures. The model was used to examine the relationship between orders and shipments of machinery and equipment industries.

This paper describes the efforts of an operations-research team working in the areas of order processing and production and inventory control for an engine manufacturing company Mathematical models were developed and adjusted to the needs of the company Results were expressed as decision rules, some of which served as tools for clerical personnel, others of which became the bases of logical decisions for an electronic digital computer Implementation of results was initiated through training of company personnel and the formation of an ongoing operations-research group within the company [ABSTRACT FROM AUTHOR]

For an inventory model with a central warehouse that supplies two satellite warehouses an approximation of the cost function by upper and lower bounds is presented under the assumption that the satellites follow (s, S) policies that are optimal for the satellites alone. The difference between these upper and lower bounds for each period is less than a fixed number. In the infinite horizon model with a discount rate less than one this difference is less than a constant that depends on the mean of the demands, the holding, and the penalty costs. The results are shown for two satellites, they can easily be generalized to k satellites. [ABSTRACT FROM AUTHOR]

For the infinite horizon, single item inventory problem, assume an ordering cost M(i) + K(j) for changing the stock level from i to j (for example, M(i) + K(j) = c·(j - i) + K), a holding plus shortage cost l(j), and a probability ϕ(j, k) of demand j - k when the stock level is j. New conditions for optimality of (s, S) policies are given, and a computational method is given. Both the total discounted cost and the average cost criteria are treated. The method is simplified when the demand distribution is Bernoulli or geometric. When, in addition, the costs K(j) = K, and l(x) is - Lx for x > 0, zero for 0 ≦ x ≦ I, for some I ≧ 0, and H(x - I) for x > I, then conditions are given for an optimal policy (s*, S*) to have s* = -1 or S* = I. Further, for the same assumptions but without the integrality restriction on s and S, specific formulas are given for s* and S* when the criterion is average cost; and equations, which can be solved for s* and S*, are given when the criterion is total discounted cost. [ABSTRACT FROM AUTHOR]

Contemporary inventory management attempts to make two critical inventory decisions--the order quantity and the order point. This type of analysis presupposes that stocking of the item is economically justified. Quite obviously this will not always be the case and inventory managers have had to turn to rules of thumb which are highly inflexible and consequently these rules often suggest exactly the opposite decision from that which should be made. The profit under conditions of both stocking and non-stocking can be analytically determined and then compared in a breakeven-type analysis. The intersection point or inventory cutoff level determines the minimum demand which will justify stocking the item and is derived along with a graphical representation. Two variations are provided--one for the manufacturer who produces to stock and one for the wholesaler or retailer who orders to stock. [ABSTRACT FROM AUTHOR]

The article presents a mathematical model on the organization of the salesforce of a wholesale bakery. At the risk of achieving results of quite limited general interest, a "simple," easily quantified subject was deliberately chosen as the best place to begin to apply a theory that pretends to prescribe optimum decisions of a team in a precise way. The sales force consists of truck-driver salesmen who daily visit each of their given customers leaving, on consignment, an amount of bread to be decided by the salesman. At the end of the day the salesman returns to the plant and submits an order for the next day. For the purpose of the article, the "organization" is characterized by the way in which these orders are jointly formed. Ideally, one of the first steps in assessing a given sales organization might be to attempt to set down the existing information structure. For an individual salesman, at least six sources of information can be distinguished, first, his observations in his own market, second, his discussions with his fellow salesmen, third, his discussions with his route supervisor, fourth, "bulletins" and other relatively formal communications from the sales manager, fifth, his short end-of-the-day encounter with the order clerk, and sixth, inference from the actual quantity of goods supplied him at the beginning of the day.

Finally the conclusions must be seen in the context of this study's limitations namely (a) little investigation of the structural parameter space, (b) the use of correctly specified structural equations, 3 (c) no consideration of the comparative performance of other consistent but non-iterative methods and (d) an inadequate treatment of the choice of initial estimates and the associated problem of multiple convergence. Also we have restricted our comparisons to the case of low order moving average and autoregressive errors. The results may of course differ when higher order processes are compared. [ABSTRACT FROM AUTHOR]

This article focuses on the relation between the pressure of internal demand and the British export performance. A high pressure of demand, somehow defined, leads to a situation in which manufacturers divert productive resources away from meeting the export orders, towards satisfying home demand. Such a shift of resources leads to lengthening of the order-delivery lags for export orders on the supply side. On the demand side lengthening of the lads may lead to a fall in the new orders. In this paper, distributed-lag model is proposed and estimated.

The article presents comments on the article "A Few Remarks on the Assortment Problem," by Wieslaw Sadowski in the October 1959 issue. In his article, Sadowski proposed a dynamic programming approach to the solution of the assortment problem by showing its equivalence to the shortest route problem by using Bellman's algorithm. The author offers an alternative solution which solves a more general problem and proves a theorem which reduces the amount of computation necessary to arrive at a solution. The solution is applied to an inventory control problem.

Two abstracts are presented for articles pertaining to the transportation of goods. The first is "Eight Washers at a Time Via Mechanical Order Picking." The second is "Costing Practices in Physical Distribution," by John H. Frederick.