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This article is concerned with choosing a mix of weapons, subject to constraints, when the targets to be attacked are known imprecisely. It is shown that the correct method for optimizing the mix of weapons involves a pair of nested optimization problems (two-stage optimization). Two methods for optimizing the expected utility of a mix are discussed. The first involves a simultaneous attack model, in which it is implicitly assumed that all weapons are used at once. The second involves a sequential attack model, in which targets appear in random order and are attacked one at a time. Particular attention is given to the question of the appropriate mix of general-purpose and special-purpose weapons.  相似文献   
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On 22 September 1979 two optical sensors on U.S. satellite Vela 6911 detected a double-flash of light that appeared characteristic of an atmospheric nuclear explosion conducted over the southern Atlantic or Indian Ocean. It became known as the Vela Incident, Event 747, or Alert 747. An anomaly between the amplitude of the two signals during the second pulse led a U.S. government expert panel established to assess the event to conclude in mid-1980 that a more likely explanation was the impact of a small meteoroid on the satellite, the debris from which reflected sunlight into the sensors' field of view. No model was presented to support the contention, and a similar anomaly—known as background modulation—was a given for the second pulse of all confirmed explosions detected by Vela, though beginning later. Nonetheless, this event has remained the subject of intense debate. This article reviews the evidence and presents an updated analysis of the original Vela signal based on recently declassified literature and on modern knowledge of interplanetary dust and hyper velocity impact. Given the geometry of the satellite, and that the bulk of the surface comprised solar panels, much of the debris from any collision would be carried away from the sensors' field of view. Thus, a meteoroid collision appears much less likely than previously assumed. The double flash is instead consistent with a nuclear explosion, albeit detected by an aged satellite for which background modulation was abnormal and/or commenced earlier, also seen in post-event SYSTEM tests. A companion paper to be published in 2018 presents radionuclide and hydroacoustic evidence supporting the conclusion that the Vela Incident was a nuclear weapon test explosion.  相似文献   
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In this paper we consider the discrete time/resource trade-off problem in project networks. Given a project network consisting of nodes (activities) and arcs (technological precedence relations), in which the duration of the activities is a discrete, nonincreasing function of the amount of a single renewable resource committed to it, the discrete time/resource trade-off problem minimizes the project makespan subject to precedence constraints and a single renewable resource constraint. For each activity, a work content is specified such that all execution modes (duration/resource requirement pairs) for performing the activity are allowed as long as the product of the duration and the resource requirement is at least as large as the specified work content. We present a tabu search procedure which is based on a decomposition of the problem into a mode assignment phase and a resource-constrained project scheduling phase with fixed mode assignments. Extensive computational experience, including a comparison with other local search methods, is reported. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 553–578, 1998  相似文献   
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武警学院边消警部队政治工作专业的研究生教学要抓好的问题是:选准苗子,严格把好研究生的入学关;做好教学的各项准备工作,严格把好教学关;注意各方协调,齐抓共管,把好对研究生的管理关;不断加强研究生教学的硬件建设,把好保障关;坚持各项政策标准和原则,把好研究生毕业质量关。  相似文献   
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Within the EU France devotes to defence the largest financial and human resources although it is not the richest country, nor has it the largest population or labour force. The cost of nuclear weapons accounts for only a small fraction of this abnormally high French defence effort. If France had restructured its military capabilities at the same rate as its principal Allies during the 1985–1994 period, then French defence outlays would be about 20% less than at present. The fundamental reasons for France's excess defence outlay comprise virtual total dependence on French sources for equipment, produced in very small numbers; a military presence outside of Europe; and too many personnel. These deficiencies, and the consequent absence hitherto of a “peace dividend”, indicate a failure to identify the country's real strategic requirements, and a lack of will to reorganise efficiently French defence. The recently announced reform towards an all‐professional force is unlikely to achieve the potential and desirable improvement in cost‐effectiveness.  相似文献   
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The Christian resistance to the Arab invasion of Spain in 711 tends to be glossed over as a sideshow in what is usually presented as the inexorable progress of the conquest. This reflects the bias of our meagre sources, which mostly take the Arab perspective. Nevertheless, with close consideration and careful handling of these sources, we can draw from them an impression of a persistent insurgency that presented a real problem to the Islamic authorities and induced them to take both political and military countermeasures. This paper suggests how the resistance formed, its organization and tactics, and why the Arabs were unable to suppress it.  相似文献   
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Following the emergence of a communist regime in South Yemen and the multiplication of subversive movements in the United Kingdom's Gulf protectorates, British policymakers genuinely feared the spread of communism throughout southern Arabia. Defeating the People's Front for the Liberation for the Occupied Arabian Gulf (PFLOAG) insurgency in Oman's Dhofar province was considered central to preventing such an outcome. In their pursuit of victory, British officers overthrew the sultan of Oman, escalated the war by conducting attacks in South Yemen, and, ultimately, appealed to Islam as a means of rallying support against communism. However, lessons learned in previous counterinsurgencies (Malaya, Kenya, and Borneo) proved of only limited value in Oman's physical and cultural environment. Unfortunately, none of these measures worked as anticipated. Only Iran's direct military intervention and the dramatic growth of Oman's financial resources after the 1973 oil crisis provided the resources to conduct large-scale offensive operations. Even so, victory was only achieved in 1975 because the rebellion's leaders unwisely attempted to oppose the Anglo–Omani offensives conventionally.  相似文献   
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Budgetary pressures have driven a steady expansion of armaments collaboration projects internationally. This has also been the case in Europe where it is estimated that currently one-fifth of European procurement budgets are spent on collaborative weapons systems and the European Defence Agency has the long-term objective of increasing this figure by over 50%. The purpose of this article is to assess whether collaborative armaments projects can offer the benefits frequently attributed to them. To this end, the study examines the five combat aircraft projects that European states have collaboratively undertaken since the 1950s.  相似文献   
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