Operations Research articles from September 2004

Operations Research archives from September 2004

Scheduling commercial videotapes in broadcast television.
September 1, 2004... This paper, motivated by the experiences of a major U.S.-based broadcast television network, presents algorithms and heuristics to schedule commercial videotapes. Major advertisers purchase several slots to air commercials during a given time...

Computation of minimum-volume covering ellipsoids.
September 1, 2004... We present a practical algorithm for computing the minimum-volume n-dimensional ellipsoid that must contain m given points [a.sub.1],..., [a.sub.m] [member of] [R.sup.n]. This convex constrained problem arises in a variety of applied...

Order volatility and supply chain costs.
September 1, 2004... The bullwhip effect (amplification of order variance from a downstream stage in a supply chain to an upstream stage) is widely observed in practice, and is generally considered a major cause of supply chain inefficiencies. But are supply chains...

An exact algorithm for the capacitated vehicle routing problem based on a two-commodity network flow formulation.
September 1, 2004... The capacitated vehicle routing problem (CVRP) is the problem in which a set of identical vehicles located at a central depot is to be optimally routed to supply customers with known demands subject to vehicle capacity constraints. In this...

Optimal policies for a capacitated two-echelon inventory system.
September 1, 2004... This paper demonstrates optimal policies for capacitated serial multiechelon production/inventory systems. Extending the Clark and Scarf (1960) model to include installations with production capacity limits, we demonstrate that a modified...

An invariance relation and a unified method to derive stationary queue-length distributions.
September 1, 2004... For a broad class of discrete- and continuous-time queueing systems, we show that the stationary number of customers in system (queue plus servers) is the sum of two independent random variables, one of which is the stationary number of...

A Brownian approximation of a production-inventory system with a manufacturer that subcontracts.
September 1, 2004... This paper considers a production-inventory problem where a manufacturer fulfills stochastic, stationary demand for a single product from a finished-goods inventory. The inventory can be replenished by two production resources, in-house...

Replacement decisions with maintenance under uncertainty: an imbedded optimal control model.
September 1, 2004... How should a manager make replacement decisions for a chain of machines over time if each is maintained by an optimal control model addressing uncertainty of machine breakdowns? A network representation of the problem involves arcs with...

Lost-sales problems with stochastic lead times: Convexity results for base-stock policies.(Technical Note)
September 1, 2004... We consider a single-location inventory system with periodic review and stochastic demand. It places replenishment orders to raise the inventory position--that is, inventory on hand plus inventory in transit--to exactly S at the beginning of...

Relationships among three assumptions in revenue management.(Technical Note)
September 1, 2004... This note discusses the relationships among three assumptions that appear frequently in the pricing/revenue management literature. These assumptions are mostly needed for analytical tractability, and they have the common property of ensuring a...