On the design of a tandem queue with blocking: Modeling,analysis, and gradient estimation

We demonstrate here how recent advances in the study of discrete-event stochastic systems provide fruitful results for the modeling, analysis, and design of manufacturing systems. We consider a multistage make-to-stock system where outputs from the final stage are used to satisfy customer demands. We address the problem of finding the appropriate trade-off between reduced order waiting time and increased process speeds. Using the idea of infinitesimal perturbation analysis (IPA), we establish a simple procedure where sample-path derivatives can be obtained along an arbitrary sample path. Under suitable conditions, we demonstrate that these derivative estimators are unbiased and strongly consistent and can be used in a classical stochastic optimization scheme to solve the problem. The role of continuity and convexity on the validity of the estimator is also addressed. Although the focus of this article is not to solve for the optimal solution, we provide a theoretical justification for such a pursuit. The approach is appealing as it is numerically stable, easy to implement, and can be extended to other system performance measures. © 1994 John Wiley & Sons, Inc.     

Book Reviews

Iain McCallum, Blood Brothers Hiram and Hudson Maxim: Pioneers of Modern Warfare. London: Chatham, 1999. Pp. 224, 33 illus., 2 maps, biblio., index. £20. ISBN 1–86176–096–5.

Eric Ash, Sir Frederick Sykes and the Air Revolution, 1912–1918. London and Portland, OR: Frank Cass, 1999. Pp.xviii + 268, 20 illus., 3 maps, biblio., index. £42.50/$59.50 (cloth), £18.50/$27.50 (paper). ISBN 0–7146–4828–0 and ‐4382–3.

Azar Gat, Fascist and Liberal Visions of War: Fuller, Liddell Hart, Douhet, and other Modernists. Oxford: Clarendon Press, 1998. Ppviii + 334, biblio., index. £45. ISBN 0–19–820715–8.

David B. Woolner (ed.), The Second Quebec Conference Revisited: Waging War, Formulating Peace: Canada, Great Britain, and the United States in 1944–1945. Basingstoke; London: Macmillan Press, 1998. Pp.xiii + 210, index. £32.50. ISBN 0–333–75970–2.

Jeffrey Grey. Up Top: The Royal Australian Navy and Southeast Asian Conflicts 1955–1972. St Leonards NSW: Allen &; Unwin in association with the Australian War Memorial, 1998. Pp.xx + 380, 110 illus., 12 tables, 23 maps &; diagrams, appendices, notes, biblio., index. NP. ISBN 1–86448–290–7.

Susan L Carruthers, The Media at War. Basingstoke: Macmillan, 2000. Pp.321, biblio., index. £14.99 (paper). ISBN 0–333–69143–1, also available in hardback.

Edward J. Marolda and Robert J. Schneller Jr, Shield and Sword: The United States Navy and the Persian Gulf War. Washington DC: Naval Historical Center, 1998. Pp.xxi + 517, 120 illus., 14 maps, biblio., index. NP. ISBN 0–1604–9476–1.

Marvin Pokrant, Desert Shield at Sea: What the Navy Really Did and Desert Storm at Sea: What the Navy Really Did. Both Westport, CT: Greenwood Press, 1999. Pp.xxiii + 265,9 illus., biblio., index. £44.95. ISBN 0–313–31023–8. Pp.xxiv + 329,12 illus., biblio., index. NP. ISBN 0–313–31024–6.

David Kaularich and Ronald C. Kramer, Crimes of the American Nuclear State: At Home and Abroad. Boston: Northeastern University Press, 1999. Pp.xviii + 195, biblio., index. £42.75. ISBN 1–55553–371‐X.

Stanley Hoffmann, World Disorders: Troubled Peace in the Post‐Cold War Era. Lanham, MD: Rowman &; Littlefield, 1998. Pp.viii+279, notes, index. $29.95. ISBN 0–8476–8574–8.

Lawrence Freedman (ed.), Strategic Coercion: Concepts and Cases. Oxford: Oxford‐University Press, 1998. Pp.400, index. £48. ISBN 0–19–829–349–6.

Stephen J. Cimbala, Coercive Military Strategy. College Station, TX: Texas A&;M University Press, 1998. Pp.229, biblio, index; $39.95. ISBN 0–89096–836–5     

Optimal inventory policy when stockouts alter demand

An inventory model in which future demand is affected by stockouts has been considered recently by B. L. Schwartz. Some generalizations of Schwartz's model are presented in this paper and properties of the optimal policies are determined. In the case of deterministic demand, a set-up cost is included and a mixture of backlogged and nonbacklogged orders is allowed during stockout. It is proved that the optimal policy entails either no stockout or continual stockout, depending on the values of three parameters. For stochastic demand, the effect of stockouts on demand density is postulated, the resulting optimal inventory policy is discussed, and an example involving an exponential density function is then analyzed in detail.     

Analysis of a new vehicle scheduling and location problem

We consider a container terminal discharging containers from a ship and locating them in the terminal yard. Each container has a number of potential locations in the yard where it can be stored. Containers are moved from the ship to the yard using a fleet of vehicles, each of which can carry one container at a time. The problem is to assign each container to a yard location and dispatch vehicles to the containers so as to minimize the time it takes to download all the containers from the ship. We show that the problem is NP‐hard and develop a heuristic algorithm based on formulating the problem as an assignment problem. The effectiveness of the heuristic is analyzed from both worst‐case and computational points of view. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 363–385, 2001     

Countering Insurgent-terrorism: Why Nato Chose The Wrong Historical Foundation For Cimic

History teaches that counterinsurgency and counterterrorism campaigns have never been won through purely military action. Defeating an opponent who avoids open battle, but who uses force to reach his goals, including terrorist action, requires a combination of police, administrative, economic and military measures. As a counterinsurgency campaign should pursue a comprehensive political objective, it requires high levels of civil–military cooperation. However, current NATO doctrine for Civil–Military Cooperation (CIMIC) as it emerged from the 1990s is founded in conventional war-fighting and outdated peacekeeping doctrine. CIMIC's focus is on supporting military objectives rather than enabling the military to make a coherent contribution to political objectives. This makes CIMIC unfit for the Alliance's main operational challenges that have expanded from peace operations on the Balkans to countering insurgent terrorism in Afghanistan. When developing CIMIC, the Alliance obviously neglected the historical lessons from counterinsurgency campaigns.     

A Cryptographic Escrow for Treaty Declarations and Step-by-Step Verification

The verification of arms-control and disarmament agreements requires states to provide declarations, including information on sensitive military sites and assets. There are important cases, however, in which negotiations of these agreements are impeded because states are reluctant to provide any such data, because of concerns about prematurely handing over militarily significant information. To address this challenge, we present a cryptographic escrow that allows a state to make a complete declaration of sites and assets at the outset and commit to its content, but only reveal the sensitive information therein sequentially. Combined with an inspection regime, our escrow allows for step-by-step verification of the correctness and completeness of the initial declaration so that the information release and inspections keep pace with parallel diplomatic and political processes. We apply this approach to the possible denuclearization of North Korea. Such approach can be applied, however, to any agreement requiring the sharing of sensitive information.     

Quantification of contractor risk

This paper presents a quantitative index of the level of risk assumed by a contractor in various contract type situations. The definition includes expression of real world uncertainty and contractor's utility for money. Examples are given for the major contract types and special applications are discussed.