The reliability of multicomponent systems subject to cannibalization

A reliability model for multicomponent multistate systems is presented. This is a generalization of a model previously studied by Hirsch, Meisner, and Boll. In the earlier model, when a failure occurs for which no replacement spare is available, the locations using the same type of part as that having failed are “cannibalized” so as to allocate the shortages to locations where they are least detrimental to system performance. Here, we permit certain restrictions to be imposed upon the cannibalization procedure, and develop effective techniques for relating the probability laws governing the level of system performance to the system structure, cannibalization policy, kit of spare parts, and part reliabilities.     

Optimal control of continuous-time terminal-value birth-and-death processes and airline overbooking

Consider a continuous-time airline overbooking problem that relates to a single-leg flight and a single service class with a stationary fare. Passengers may cancel their reservations at any time and receive a full refund. Therefore fares can be thought of as being paid at flight time. At that time, the airline bumps passengers in excess of flight capacity and pays a penalty for so doing. The wflight-time revenue, that is, fares received less bumping penalties paid, is quasiconcave in the number of reservations at that time. We model the reservations process as a continuous-time terminal-value birth-and-death process. A more general model than is necessary for an airline reservations system is considered, in which the airline controls both the reservation acceptance (birth) and the cancellation (death) rates. In current practice airlines do not control cancellation rates (though other industries do exercise such control, e.g., hotels) and control reservation acceptance rates by declining reservation requests. The more general model might be applied to other targeting applications, such as steering a vehicle through space toward a target location. For the general model a piecewise-constant booking-limit policy is optimal; that is, at all times the airline accepts reservation requests up to a booking limit if the current number of reservations is less than that booking limit, and declines reservation requests otherwise. When the airline is allowed to decline all reservation requests, as is the case in practice, the booking-limit optimal policy defined by using the greatest optimal booking limit at all times is piecewise constant. Moreover, these booking limits fall toward flight time. © 1996 John Wiley & Sons, Inc.     

Learning to Fight and Fighting to Learn: Practitioners and the Role of Unit Publications in VIII Fighter Command 1943–1944

A military cannot hope to improve in wartime if it cannot learn. Ideally, in wartime, formal learning ceases and the application of knowledge begins. But this is optimistic. In 1942, USAAF Eighth Air Force assumed it had the means necessary for victory. In reality, its technique and technology were only potentially – rather than actually – effective. What remained was to create the practice of daylight bombing – to learn. This article (1) recovers a wartime learning process that created new knowledge, (2) tests existing tacit hypotheses in military adaptation research, and (3) offers additional theoretical foundation to explain how knowledge is created in wartime     

British Policy on Total Maritime Warfare and the Anti-Shipping Campaign in the Mediterranean, 1940–1944

During World War II, the British ran a sustained anti-shipping campaign against Axis merchant and supply traffic in the Mediterranean. Although the effects of this on the land war in North Africa have been the subject of much debate, little attention has been paid to the nature and prosecution of the campaign itself. This article analyses the changes in British attitudes and policy towards attacking merchant shipping prior to and throughout the campaign. It then goes on to examine the conduct of the campaign itself and compare it with other British efforts elsewhere during the war. It concludes that the anti-shipping campaign in the Mediterranean was a unique combined arms offensive for the British, and a major evolution in their attitudes and policy towards maritime total war.     

Rent‐seeking models of international competition: An experimental investigation*

This paper experimentally tests a number of hypotheses that follow from models of international competition that are based on Tullock style rent‐seeking models. Specifically, we designed and performed experiments to see how variations in the degree of publicness in the prize as well as changes in the values assigned to the prize affect alliances in terms of individual nation contributions, total contributions, burden sharing, and the likelihood of winning the prize. While there was substantial variation in individual behavior, the results of the experiments generally conform to the theoretical predictions of the rent‐seeking model of international competition and alliances.