The location-allocation problem for existing facilities uniformly distributed over rectangular regions is treated for the case where the rectilinear norm is used. The new facilities are to be located such that the expected total weighted distance is minimized. Properties of the problem are discussed. A branch and bound algorithm is developed for the exact solution of the problem. Computational results are given for different sized problems. 相似文献
It is well known that a minimal makespan permutation sequence exists for the n × 3 flow shop problem and for the n × m flow shop problem with no inprocess waiting when processing times for both types of problems are positive. It is shown in this paper that when the assumption of positive processing times is relaxed to include nonnegative processing times, optimality of permutation schedules cannot be guaranteed. 相似文献
In a 1973 paper J. D. Esary, A. W. Marshall, and F. Proschan [5] considered a shock model giving rise to various nonparametric classes of life distributions of interest in reliability theory. A number of authors have extended these results in a variety of directions. In this paper, alternative proofs of the increasing failure rate (IFR) and decreasing mean residual life (DMRL) results are given which do not make use of the theory of total positivity. Some bivariate extensions are then obtained using a shock model similar to that originally used by H. W. Block, A. S. Paulson, and R. C. Kohberger [2] to unify various bivariate exponential distributions. 相似文献
Constrained multi-item inventory models have long presented signifcant computational problems. This article presents a general algorithm to obtain simultaneous solutions for order quantities and safety stocks for each line item in an inventory, while satisfying constraints on average inventory investment and reordering workload. Computational experience is presented that demonstrates the algorithm's efficiency in handling large-scale applications. Decision rules for several customer service objectives are developed, with a discussion of the characteristics of the inventory systems in which each objective would be most appropriate. The decision rules are approximations, based on the assumptions commonly used in practice. 相似文献
This article discusses the impact of Complex Humanitarian Emergencies on the delivery of humanitarian aids. Complex emergencies were the results of long-term political and social disputes. Its impact brings about public health crises like epidemics, malnutrition, and even widespread desperation. In fact, there are four aspects of these crises which complicate public health programs: 1) emergencies are long and recurring; 2) access to the most vulnerable population is often restricted; 3) restructuring health systems in complex emergencies can be futile; and 4) complex emergencies often result in mass forced migration. What makes matters worse is the breakdown of health networks which collapse early in complex emergencies, leading to extensive losses of human health resources. Not only that, health facilities and transportation, infrastructure are often decimated in complex emergencies, and regional hospitals, district health posts, laboratories, and primary care outposts are similarly abandoned or destroyed. Moreover, because it is difficult to predict the course of these emergencies, ascertaining the optimal time to intervene and to invest in materials and facilities that could be lost to renewed fighting can be impossible. To solve this problem requires a coordinated effort. It should also focus on resources, early warning systems, preparedness measures, ongoing career training of relief workers, and prepositioning of relief supplies. 相似文献
Strategic Views from the Second Tien The Nuclear Weapons Policies of France, Britain and China. Edited by J.C. Hopkins and W Hu, New Brunswick and London, Transaction Publishers, (1995) ISBN 1-56000-7907. $ 21.95
Multinational Military Forces: Problems and Prospects. By Roger H. Palin. Adelphi Paper 294, 11SS/Oxford University Press (1995) ISBN 0-19-828025-4 ISSN 0567 932X
South Africa in the Global Economy. Edited by Greg Mills, et al. South African Institute of International Affairs, Johannesburg, (1995) ISBN 1-874890-58-7. R. 45.60
The Limits of Air Powen The American Bombing of North Vietnam. By Mark Clodfelter, The Free Press. New York (1989). ISBN 0-02-905990-9. $22.95.
Guy Gibson. By Richard Morris with Colin Dobinson. Viking. London (1994). ISBN 0-670-82878-5. £18.00.
Dambuster: A Life of Guy Gibson VC. By Susan Ottway. Leo Cooper, London (1994). ISBN 0-85052-427. £16-95. 相似文献
This article considers the problem of allocating a fixed budget among alternative air-to-ground weapons. The weapon-budgeting problem is high-dimensional, involving all feasible combinations of aircraft, weapons, and targets. The decision maker's utility function is defined over kills of the various target types, but it is unrealistic to expect him to write down the mathematical formula for this function. The article suggests two procedures for reducing the dimension of the maximization problem and operating without exact knowledge of the utility function. The first procedure uses successive linear approximations to generate the set of “efficient” or undominated weapon allocations. The second procedure applies separability restrictions to the utility function, thereby reducing the overall maximization problem to a sequence of low-dimensional subproblems. 相似文献
America's Secret Power: the CIA in a Democratic Society. By Loch K. Johnson. Oxford University Press, New York (1989), ISBN 0–19–505490–3, $24.95
The Bundeswehr and Western Security. Edited by Stephen F. Szabo. Houndmills, Basingstoke, and Macmillan, London (1990), ISBN 0–333–49880–1, £45.00
Symbolic Defense: the Cultural Significance of the Strategic Defense Initiative. By Edward Tabor Linenthal. University of Illinois Press, Chicago, IL (1989), ISBN 0–252–01619‐X, $19.95
Rethinking European Security. Edited by Furio Cerutti and Rodolfo Ragionieri. Crane Russak, New York (1990), £29.00
Alternative Conventional Defense Postures in the European Theater, Vol. 1: The Military Balance and Domestic Constraints. Edited by Hans Günter Brauch and Robert Kennedy, Crane Russak, New York (1990), £32.00
The Gulf War. Edited by Hanns Maull and Otto Pick. Pinter, London (1989), ISBN 0–86187–763–2, £36.00 相似文献
India and Pakistan are currently engaged in a competition for escalation dominance. While New Delhi is preparing for a limited conventional campaign against Pakistan, Islamabad is pursuing limited nuclear options to deter India. Together, these trends could increase the likelihood of nuclear conflict. India, for example, might conclude that it can launch an invasion without provoking a nuclear reprisal, while Pakistan might believe that it can employ nuclear weapons without triggering a nuclear exchange. Even if war can be avoided, these trends could eventually compel India to develop its own limited nuclear options in an effort to enhance deterrence and gain coercive leverage over Pakistan. 相似文献