A two-phase procedure for allotting geostationary orbital locations to communications satellites

We consider the problem of allotting locations in the geostationary orbit to communication satellites, subject to angle of elevation and electromagnetic interference constraints. An optimization framework is used as a means of finding feasible allotment plans. Specifically, we present a two-phase solution procedure for the satellite location problem (SLP). The objective in SLP is to allot geostationary orbital locations to satellites so as to minimize the sum of the absolute differences between the locations prescribed for the satellites and corresponding specified desired locations. We describe two heuristics, an ordering procedure and a k-permutation algorithm, that are used in tandem to find solutions to SLP. Solutions to a worldwide example problem with 183 satellites serving 208 service areas are summarized.     

CHOOSING GENOCIDE: ECONOMIC PERSPECTIVES ON THE DISTURBING RATIONALITY OF RACE MURDER

An economic theory of genocide is presented with application to Rwanda‐1994. The theory considers ‘macro’ conditions under which an authority group chooses genocide and ‘micro’ conditions that facilitate the spread of genocide. From the macro perspective, a bargaining model highlights four rational explanations for an authority’s choice of genocide: prevention of loss of power, indivisibility, elimination of a persistent rival, and political bias. From the micro perspective, an evolutionary game model shows how supporters of genocide gain the upper hand in group dynamics over resisters and bystanders. The theory and application suggest that the conditions for genocide are not exceptional.     

End of the cycle: assessing ETA’s strategies of terrorism

ABSTRACT

In May 2018, the Basque insurgent group Euskadi Ta Askatasuna (ETA) officially disbanded after a 60-year struggle. This inquiry assesses ETA’s violent campaigns using recent conceptual and theoretical advancements from the field of terrorism studies. Three conclusions concerning the group’s strategies of terrorism are advanced. First, ETA regularly targeted civilians to achieve goals other than coercing the Government of Spain; these objectives included outbidding rival separatist groups and spoiling negotiation processes. Second, ETA’s most rapid period of organizational growth occurred as the result of an aggressive terrorist campaign, demonstrating that civilian targeting can serve as a stimulus to rebel group recruitment. Finally, while terrorism did not advance ETA’s primary political objective of creating an independent Basque state, it did enable the group to assume a leading position within the radical Basque separatist movement, helping extend ETA’s lifespan and making the group an embedded actor within the contentious political processes surrounding the question of Basque self-determination. Collectively, these conclusions support recent theoretical findings arguing that non-state terrorism often enables insurgent groups to prolong their lifespans while paradoxically making it more difficult for them to advance their long-term political objectives.     

A note on minimizing the expected makespan in flowshops subject to breakdowns

Consider a two machine flow shop and n jobs. The processing time of job j on machine i is equal to the random variable X_ij One of the two machines is subject to breakdown and repair. The objective is to find the schedule that minimizes the expected makespan. Two results are shown. First, ifP(X_2j ≧ X_1j) = 1 for all j and the random variables X₁₁, X₁₂,…, X_1n are likelihood ratio ordered, then the SEPT sequence minimizes the expected makespan when machine 2 is subject to an arbitrary breakdown process; if P(X_1j≧X_2j) = 1 and X₂₁, X₂₂,….,X_2n are likelihood ratio ordered, then the LEPT sequence minimizes the expected makespan when machine 1 is subject to an arbitrary breakdown process. A generalization is presented for flow shops with m machines. Second, consider the case where X_1j and X_2j are i.i.d. exponentially distributed with rate λ_j. The SEPT sequence minimizes the expected makespan when machine 2 is subject to an arbitrary breakdown process and the LEPT sequence is optimal when machine 1 is subject to an arbitrary breakdown process. © 1995 John Wiley & Sons, Inc.     

Warranty reserving

This paper considers a problem of warranty reserving, namely, the current practice of setting aside part of a product revenue to meet future claims arising from the warranty. We define a Compound Poisson stochastic model for warranty claims and reserve and obtain, using a sample paths technique, the long-run probability distribution of a warranty reserves, managed under alternative warranties and reserve policies.     

Guerrillas and bandits in the Serranía de Ronda, 1810–1812

The Spanish Guerrilla (1808–1812) which has given its name to ideologically motivated insurgencies is usually portrayed as a patriotic uprising against the French occupation forces of Napoleon. It was that, in part, but also many other things besides. This case study illustrates its overlap and convergence with banditry but also with social unrest turned into uprisings directed by poor Spaniards against their creditors, as in the storming of Ronda by insurgents in 1810. From the propaganda of the day to the subsequent Spanish patriotic historiography, there has been a tendency to exaggerate the amplitude of events and also the damage that was done to the French forces and the casualty figures inflicted on them.     

ON RATIONAL CHOICE THEORY AND THE STUDY OF TERRORISM

When rational choice theory is applied to the study of terrorism, it is important that attention be given to the derived principles of constrained utility maximization. Particularly useful is the Slutsky equation, which rigorously analyzes the quantity response in one activity to a price change in another. By directing attention to assumptions and/or information about compensated cross price elasticities, expenditure shares, and income elasticities, the Slutsky equation can provide critical guidance in both theoretical and empirical analysis.     

Convergence of the bounded fixed charge programming problem

Calculating the solution for a mixed integer linear programming problem has been problematic for any sizable dimension because of the time required. Accordingly, an improved method for the fixed charge problem is presented here. The method is a modification of a bounding technique first suggested by Balinski, and it exploits fully the ratio of costio-use, first described by Cooper and Drebes. It exploits those local properties which have global application so that enumeration is confined to those relatively few combinations which cannot be evaluated otherwise.