Strategy

We consider inventory systems with several distinct items. Demands occur at constant, item specific rates. The items are interdependent because of jointly incurred fixed procurement costs: The joint cost structure reflects general economies of scale, merely assuming a monotonicity and concavity (submodularity) property. Under a power-of-two policy each item is replenished with constant reorder intervals which are power-of-two multiples of some fixed or variable base planning period.

The reorder point/reorder quantity policies, also referred to as (r, Q) policies, are widely used in industry and extensively studied in the literature. However, for a period of almost 30 years there has been no efficient algorithm for computing optimal control parameteres for such policies. In this paper, we present a surprisingly simple and efficient algorithm for the determination of an optimal (r*, Q*) policy. The computational complexity of the algorithm is linear in Q*.

When futures contracts are settled with respect to underlying asset prices, received theory suggests that the differences between futures prices and implied forward prices (from the term structure) are strictly due to marking to market, ceteris paribus. Empirical evidence appears to indicate that such differences are small for contracts with short maturities. What happens when the futures contract settles to yields implied by future prices of underlying assets?

This paper examines the allocative role of class shares that pay dividends based upon the performance of the individual activities of multi-activity firms. The firms considered operate under economies of scope and technological uncertainty in an incomplete asset market. Investor unanimity about the choice of production plans and a constrained Pareto optimum are attained when all firms in the economy issue a class of shares for each of their activities.

This paper is concerned with the general dynamic lot size model, or (generalized) Wagner-Whitin model. Let n denote the number of periods into which the planning horizon is divided. We describe a simple forward algorithm which solves the general model in 0(n log n) time and 0(n) space, as opposed to the well-known shortest path algorithm advocated over the last 30 years with 0(n2) time.

In this paper we consider a class of single-server queueing systems with compound Poisson arrivals, in which, at service completion epochs, the server has the option of taking off for one or several vacations of random length. The cost structure consists of holding cost rate specified by a general non-decreasing function of the queue size, fixed costs for initiating and terminating service, and a variable operating cost incurred for each unit of time that the system is in operation.