An inventory problem with obsolescence

A stochastic single product convex cost inventory problem is considered in which there is a probability, π_j, that the product will become obsolete in the future period j. In an interesting paper, Barankin and Denny essentially formulate the model, but do not describe some of its interesting and relevant ramifications. This paper is written not only to bring out some of these ramifications, but also to describe some computational results using this model. The computational results show that if obsolescence is a distinct possibility in the near future, it is quite important that the probabilities of obsolescence be incorporated into the model before computing the optimal policies.     

A simulated port facility in a theatre of operations

A hypothetical port facility in a theatre of operations is modeled and coded in a special purpose simulation language, for the purpose of conducting simulation experiments on a digital computer. The experiments are conducted to investigate the resource requirements necessary for the reception, discharge, and clearance of supplies at the port. Queue lengths, waiting times, facility utilizations, temporary storage levels, and ship turn-around times are analyzed as functions of transportation and cargo handling resources, using response surface methodology. The resulting response surfaces are revealing in regard to the sensitivity of port operations to transportation resource levels and the characteristics of the port facility's load factor. Two specific conclusions of significant value are derived. First, the simulation experiments clearly show that the standard procedures for determining discharge and clearance capacities take insufficient account of the effects of variability. Second, the response surfaces for ship turn-around times and temporary storage levels indicate that an extremely steep gradient exists as a function of troop levels.     

Troubled triangle: Russia,Ukraine and the United States

A potentially productive triangular arrangement among Russia, Ukraine, and the United States emerged in 1994 from efforts to constrain nuclear weapons diffusion. By 2001, this promising initiative was nearly moribund, owing to the inability or unwillingness of the parties to fulfill the commitments of subsequent agreements. The domestic and external causes of this failure are many and clear. Yet the advantages to each of reengaging in a trilateral relationship are also plain. This means fulfilling their unfinished agenda by learning from past mistakes, adopting realistic premises and goals, and pursuing ‘bottom up’ as well as ‘top down’ strategies.     

Did the Panamanian Defense Forces conduct infiltration operations at the Arraijan Tank Farm in 1988?

This article reviews the circumstances surrounding a relatively obscure and almost forgotten US Marine Corps and Army security enhancement operation undertaken in Panama that commenced in early April of 1988. Marines were sent to Panama to protect oil and ammunition storage facilities from potential saboteurs. By April 1989 they had reported sighting armed, uniformed intruders on at least 43 occasions and receiving gunfire or discharging their own weapons during 16 incidents. Yet despite the repeated barrages of small arms fire over the course of a year, they failed to recover enemy ammunition, bodies or body parts and their own equipment and positions displayed no signs of suffering from hostile fire. This article analyzes the events from the point of view of a veteran of the operation and highlights the role that psychological operations may have played in generating the situation.