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661.
We consider the nonpermutation flow shop problem with release dates, with the objective of minimizing the sum of the weighted completion times on the final machine. Since the problem is NP‐hard, we focus on the analysis of the performance of several approximation algorithms, all of which are related to the classical Weighted Shortest Processing Time Among Available Jobs heuristic. In particular, we perform a probabilistic analysis and prove that two online heuristics and one offline heuristic are asymptotically optimal. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.  相似文献   
662.
663.
We present two frameworks for designing random search methods for discrete simulation optimization. One of our frameworks is very broad (in that it includes many random search methods), whereas the other one considers a special class of random search methods called point‐based methods, that move iteratively between points within the feasible region. Our frameworks involve averaging, in that all decisions that require estimates of the objective function values at various feasible solutions are based on the averages of all observations collected at these solutions so far. Also, the methods are adaptive in that they can use information gathered in previous iterations to decide how simulation effort is expended in the current iteration. We show that the methods within our frameworks are almost surely globally convergent under mild conditions. Thus, the generality of our frameworks and associated convergence guarantees makes the frameworks useful to algorithm developers wishing to design efficient and rigorous procedures for simulation optimization. We also present two variants of the simulated annealing (SA) algorithm and provide their convergence analysis as example application of our point‐based framework. Finally, we provide numerical results that demonstrate the empirical effectiveness of averaging and adaptivity in the context of SA. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012  相似文献   
664.
This paper addresses a two‐machine open shop scheduling problem, in which the machines are not continuously available for processing. The processing of an operation affected by a non‐availability interval can be interrupted and resumed later. The objective is to minimize the makespan. We present two polynomial‐time approximation schemes, one of which handles the problem with one non‐availability interval on each machine and the other for the problem with several non‐availability intervals on one of the machines. Problems with a more general structure of the non‐availability intervals are not approximable in polynomial time within a constant factor, unless . © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006  相似文献   
665.
This article examines the relationship between the White House and the US Military Assistance Command, Vietnam (MACV) during President Richard M. Nixon's administration. It argues that dysfunctional civil-military relations between 1969 and 1972 undermined the implementation of a sound military strategy during the United States' withdrawal from South Vietnam as Nixon attempted to achieve ‘peace with honor’ during the Vietnam War's final campaigns. By 1972, the relationship between the White House and MACV headquarters had reached the nadir of civil-military relations during the Southeast Asian conflict and had served to undercut the United States' ability to effectively disengage from a long and bitterly contested war.  相似文献   
666.
This article analyses the evolution of permanent fortifications in Europe between 1870 and 1914. Despite the introduction in the 1880s of high explosive shells, intensive construction continued until the eve of war. Fortifications figured prominently in armaments budgets and in offensive as well as defensive strategic planning, while their design changed radically. Nonetheless, the pattern of development worked against the Central Powers. Austria-Hungary concentrated against Italy at the expense of the Balkans and Galicia; Germany concentrated on Alsace-Lorraine, neglecting the east until 1912. Whereas France modernised its eastern fortresses, Belgium did little, enticing Germany into the envelopment strategy that would draw Britain into the First World War.  相似文献   
667.
668.
Since the end of the Cold War, India's strategic horizons have moved beyond its traditional preoccupations in South Asia. India is developing a strategic role in East Asia in particular. At the same time India's strategic thinking has undergone a revolution, as the country that prided itself on non-alignment has moved closer to the West. But India's culture, history and geography still fundamentally shape its worldview. In engaging with East Asia, India is guided by a mosaic of strategic objectives about extending its sphere of influence, developing a multipolar regional system and balancing against China. The interplay of these objectives will frame India's role in East Asia in coming years.  相似文献   
669.
The books under review here, by Robert F. Hannigan, John A. Thompson, Trygve Throntveit, and Adam Tooze, offer an interpretation of Wilsonian internationalism and what happened to it in the 1920s. For Tooze and Hannigan, Wilsonianism was primarily a project to attain American predominance in the world. For Throntveit, Wilsonian internationalism constituted a pragmatic yet radical effort to end competitive power politics. Thompson disagrees with these arguments and asserts that the key to understanding US policy lay in how US leaders conceptualized American power. Thompson’s interpretation is especially compelling in explaining why the United States failed to engage itself more assertively in international affairs in the 1920s – a failure Tooze suggests undermined the viability of the postwar international system.  相似文献   
670.
Theories of group, and individual, motivation to fight have shown little real advancement since World War II. The lively debate between the proponents of ‘primary group’ and ideological theories has tended to preclude any other analysis. The debate has continued to generalise from the experience of the Wehrmacht and its cohesion in the face of appalling destruction. In this article I suggest that the theoretical underpinnings of the debate have revolved around one particular, and somewhat unrecognised, concept of the mind. Work on combat motivation owes a substantial debt to Freudian ideas concerning the unconscious and group psychology. Both sides of the ideology/primary group debate use Freudian ideas, often without realising it, and these concepts shape the various positions taken. Only by acknowledging and examining this underpinning can the debate move forward and produce a more general theory of combat motivation and group conflict with wider application.  相似文献   
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