Local search methods for the discrete time/resource trade-off problem in project networks

In this paper we consider the discrete time/resource trade-off problem in project networks. Given a project network consisting of nodes (activities) and arcs (technological precedence relations), in which the duration of the activities is a discrete, nonincreasing function of the amount of a single renewable resource committed to it, the discrete time/resource trade-off problem minimizes the project makespan subject to precedence constraints and a single renewable resource constraint. For each activity, a work content is specified such that all execution modes (duration/resource requirement pairs) for performing the activity are allowed as long as the product of the duration and the resource requirement is at least as large as the specified work content. We present a tabu search procedure which is based on a decomposition of the problem into a mode assignment phase and a resource-constrained project scheduling phase with fixed mode assignments. Extensive computational experience, including a comparison with other local search methods, is reported. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 553–578, 1998     

Markets for surplus components with a strategic supplier

We study markets for surplus components, which allow manufacturers with excess component inventory to sell to firms with a shortage. Recent developments in internet commerce have the potential to greatly increase the efficiency of such markets. We develop a one‐period model in which a monopolist supplier sells to a number of independent manufacturers who are uncertain about demand for final goods. After uncertainty is resolved, the manufacturers have the opportunity to trade. Because uncertainty is over demand functions, the model allows us to endogenize both the price of final goods and the price of components in wholesale and surplus markets. We derive conditions on demand uncertainty that determine whether a surplus market will increase or decrease supplier profits. Increased costs of transacting on the surplus market may benefit manufacturers, because of the impact of these costs on the supplier's pricing power. The surplus market can decrease overall efficiency of the supply chain, since the benefit of better allocation of components may be outweighed by an increased double‐marginalization effect. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

Warning of Terror: Explaining the Failure of Intelligence Against Terrorism

Many scholars and analysts have studied intelligence failure and surprise and developed theories to explain disasters such as the attack on Pearl Harbor. Others, especially since the 9/11 attacks, have examined the rising threat of terrorism and see it as posing a particularly difficult challenge for the intelligence community. But little work has been done to integrate the earlier literature on intelligence failure with the newer threat of terrorist attack. This article attempts such an integration, by examining the bombing of the US Marine Barracks in Beirut in 1983; it concludes that most studies of the Beirut bombing are mistaken in their assessment of the role played by intelligence in that disaster, and suggests that our understanding of intelligence failure against surprise attacks needs to be revised in the age of terrorism.     

Nuclear‐and missile‐related trade and developments for selected countries,March ‐ June 1999

The material in this overview is drawn from selected abstracts that appear in the Center for Nonproliferation Studies’ nuclear and missile databases. Transactions of nuclear and missile technologies, parts, and materials are listed according to the recipient country. Other developments are listed according to the country where the event or development took place.     

Quantitative monitoring of military transformation in the period 1992–2010: Do the protagonists of transformation really change more than other countries?

Military transformation is a complex, slow, asymmetric, changeable, political, and not necessarily completely rational process that clearly needs an effective monitoring mechanism. This paper fills a gap in current literature by creating and testing a model for multi-dimensional and multi-level quantitative monitoring of military transformation applicable in any country. The model is based on 10 transformation indicators that reflect changes in organizational structure, personnel structure, weapon systems, and defense spending. Its application on a sample of seven countries (USA, United Kingdom, France, Netherlands, Poland, Russia, and China) in the period from 1992 to 2010 unexpectedly shows that the USA – a protagonist in the transformation process among allies as well as globally – has carried out the smallest relative change. The non-directed transformation index indicates that Russia carried out 51.8% more change (or 34.1 index units), and the directed index indicates that Poland carried out 157.2% (or 40.8 index units) more change than the USA.