Optimal layered search

This article investigates the problem of planning an optimal layered search for a stationary target. A search is layered if it assigns each point in the search space an integer number of glimpses or looks. General necessary and sufficient conditions and an existence theorem are obtained. The special case in which the initial target distribution is bivariate normal is considered in detail.     

A model for critical crack size estimation in fatigue failure of gun barrels

With repeated firing, fatigue cracks are produced in a gun barrel, and the barrel is no longer useful when a crack reaches a critical size. The initial crack size and the critical crack size, as well as the number of firings producing the critical crack size, may be considered as random variables. Assuming a proportional damage model for crack growth, a method for estimating the critical crack size distribution is presented. From these results, an estimate of the barrel life, or the residual barrel life once a crack of a given size is measured, can be obtained.     

Convex envelope results and strong formulations for a class of mixed-integer programs

In this article we present a novel technique for deriving the convex envelope of certain nonconvex fixed-charge functions of the type that arise in several related applications that have been considered in the literature. One common attribute of these problems is that they involve choosing levels for the undertaking of several activities. Two or more activities share a common resource, and a fixed charge is incurred when any of these activities is undertaken at a positive level. We consider nonconvex programming formulations for these problems in which the fixed charges are expressed in the form of concave functions. With the use of the developed convex envelope results, we show that the convex envelope relaxations of the nonconvex formulations lead to the linear programming relaxations of the strong IP/MIP formulations of these problems. Moreover, our technique for deriving convex envelopes offers a useful construct that could be exploited in other related contexts as well. © 1996 John Wiley & Sons, Inc.     

A model of the international arms market∗

Sales of arms are a significant component of international trade and raise a range of pressing policy issues. After a short review of the market, this paper provides a formal model of the trade which allows for competing forward‐looking suppliers whose welfare depends on both the economic benefits from the sales and the security repercussions of recipient behaviour. The recipient's behaviour depends on its military capability, a function of the stock of arms it has acquired. We first examine a myopic recipient, whose behaviour depends on current stocks, then a forward looking recipient for whom questions of the time‐consistency and the credibility of supplier threats to embargo or promises to resupply become crucial. Finally we examine the impact of supplier cooperation of the sort currently being discussed in the UN Security Council.     

Controlling the Sunni Insurgency in Iraq: ‘Political’ and ‘Military’ Strategies from Successful Counterinsurgency in Punjab – India

This article examines the ‘political’ and ‘military’ strategies used by the Indian state successfully to quell the Sikh insurgency in Punjab, and applies these lessons to controlling the Sunni insurgency in Iraq. At a conceptual level, this article argues that insurgencies are both a ‘military’ and ‘political’ phenomenon, and that ways to quell them can be either ‘military’ or ‘political,’ or a combination thereof. At the empirical level, this article argues that stability cannot be restored to Iraq until Sunni political actors are effectively brought into the mainstream political process through either ‘military’ or ‘political’ means, or a combination thereof. The analysis in this article provides substantive depth and detail to these otherwise seemingly straightforward propositions.     

Setting a place at the table: ending insurgencies through the political process

This article argues that, under certain conditions, allowing insurgents into the political process – through elections or government posts – can be a useful tool in the peace process and can help end insurgencies. However, bringing insurgents into the political process is unlikely to end insurgencies on its own, particularly if insurgents, the government, or the population believes that force is still a viable means of defeating the opponent and changing the status quo. The article begins with a brief overview of the causes of insurgency and on conflict resolution for internal wars. The article then considers two examples of insurgents that have entered the political process – the Irish Republican Army (IRA) in Northern Ireland and Hezbollah in Lebanon – and the differing degrees of success in transforming these insurgents to non-violent participants in the political process. It concludes by suggesting how insurgents can be brought into the political process as part of conflict resolution and the implications for Afghanistan.     

The Cyprus puzzle and the Greek - Turkish arms race: Forecasting developments using genetically evolved fuzzy cognitive maps

The scope of this paper is to forecast the extent to which a settlement of the Cyprus issue may be possible given the decisions taken during the Copenhagen EU summit. It aims, in addition, at investigating the possibilities of improvement in Greek-Turkish relations which may lead, in turn, to reducing the arms race between the two countries. The paper uses a Genetically Evolved Certainty Neuron Fuzzy Cognitive Map algorithm to consider a number of scenarios examining the possible reactions of all sides involved in the Cyprus issue, namely Greece, Turkey, Cyprus, the Turkish-Cypriot community and the international environment. All simulation exercises suggest that the Greek and the Cypriot side should not necessarily rely on the decisions taken during the Copenhagen summit conference. The forecasts point out, in addition, that the optimism of the Greek government concerning the outlook of its relations with Turkey, and a subsequent reduction of the arms race against it, is far from being justified.     

How to Fight Terrorism: Alternatives to Deterrence

Deterrence has been a crucial element in fighting terrorism, both in actual politics and rational choice analyses of terrorism. But there are superior strategies to deterrence. One is to make terrorist attacks less attractive. Another to raise the opportunity cost - rather than the material cost - to terrorists. These alternative strategies effectively dissuade potential terrorists. The strategies suggested here build on the "benevolence" system and tend to produce a positive sum game among the interacting parties. In contrast, the deterrence system is based on "threats" and tends to produce a negative sum game interaction.     

QUANTITATIVE RESTRICTIONS ON THE FLOW OF NARCOTICS: SUPPLY AND DEMAND RESTRAINTS IN A NORTH–SOUTH MACRO‐MODEL

This paper constructs a macroeconomic model of North–South interaction where the flow of narcotics from the South to the North is restricted. The economic effects are akin to quantitative restrictions in trade policy. Two alternative policy scenarios will be considered. One involves reducing the supply of drugs at the source, accompanied by aid. Supply‐side restrictions have negative aggregate supply‐side effects in the producing region, because of the monopoly rents generated from that type of control. This makes them a second‐best policy, particularly if the accompanying aid is not used for poverty alleviation and fails to expand domestic aggregate demand. Alternatively, demand side restrictions will be found to be superior.