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George Joffé 《Small Wars & Insurgencies》2016,27(1):1-21
Although the Islamic State in Iraq and al-Sham (ISIS) is seen as a novel manifestation of Islamic extremism, it is in fact the latest, albeit perhaps the most effective, of a long line of revivalist movements in the Islamic and the Arab worlds. Its motivations – hisba and jihad – differ little from its predecessors and its ambitions – to create a state organised in accordance with the precepts of the Islamic caliphate – reflect a long-standing Islamic ambition. It differs, of course, in terms of the sophistication of its political and military strategies, which mirror the contemporary complexities of the world in which it operates, but its objectives recall long-standing Islamic ideals, even if articulated in radically brutal and extremist ways. More importantly, perhaps, ISIS or Da’ish, to give it its Arabic sobriquet, reflects the enormous degree of resentment inside the Middle East at the ways in which Western powers have intervened in regional affairs over recent years, particularly their support for regimes and economic systems there that have betrayed, in the popular imaginary, the essential principles of social justice that lie at the root of Islamic vision of ideal social order. Indeed, in many respects, its analysis of the world in which it operates and of the objectives it seeks differ little in essence from those any other resistance and rejectionist movement, whether religious or sectarian. More specifically, it has been the sectarian conflict that resulted from the reversal of political order in Iraq as a result of the 2003 American-led invasion that has driven the success of the movement in capturing widespread Sunni support. Whether it can manage the complexities of the administration of a state remains open to question. 相似文献
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卡尔曼滤波算法的几何解释 总被引:5,自引:0,他引:5
对低维卡尔曼滤波算法作了几何解释 ,这种解释对卡尔曼滤波有一种直观的理解 ,使人们对卡尔曼滤波有更本质的认识。 相似文献
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An important aspect of supply chain management is dealing with demand and supply uncertainty. The uncertainty of future supply can be reduced if a company is able to obtain advance capacity information (ACI) about future supply/production capacity availability from its supplier. We address a periodic‐review inventory system under stochastic demand and stochastic limited supply, for which ACI is available. We show that the optimal ordering policy is a state‐dependent base‐stock policy characterized by a base‐stock level that is a function of ACI. We establish a link with inventory models that use advance demand information (ADI) by developing a capacitated inventory system with ADI, and we show that equivalence can only be set under a very specific and restrictive assumption, implying that ADI insights will not necessarily hold in the ACI environment. Our numerical results reveal several managerial insights. In particular, we show that ACI is most beneficial when there is sufficient flexibility to react to anticipated demand and supply capacity mismatches. Further, most of the benefits can be achieved with only limited future visibility. We also show that the system parameters affecting the value of ACI interact in a complex way and therefore need to be considered in an integrated manner. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011 相似文献
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This study presents power‐of‐two policies for a serial inventory system with constant demand rate and incremental quantity discounts at the most upstream stage. It is shown that an optimal solution is nested and follows a zero‐inventory ordering policy. To prove the effectiveness of power‐of‐two policies, a lower bound on the optimal cost is obtained. A policy that has a cost within 6% of the lower bound is developed for a fixed base planning period. For a variable base planning period, a 98% effective policy is provided. An extension is included for a system with price dependent holding costs. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
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Cedric de Coning 《Contemporary Security Policy》2017,38(1):145-160
When the United Nations (UN) Security Council needs to authorize a peace enforcement operation in Africa, its partner of choice is the African Union (AU). Africa has developed significant peace operations capacity over the past decade. In addition to deploying eight AU operations, Africa now contributes 50% of all UN peacekeepers. African stability operations, like its mission in Somalia, are often described as peace enforcement operations. In this article, I question whether it is accurate to categorize African stability operations as peace enforcement? I answer the question by considering what the criteria are that are used to differentiate between peace enforcement and peacekeeping operations in the UN context. I then use the peace enforcement criteria to assess whether AU stabilization operations would qualify as peace enforcement operations. In conclusion, I consider the implications of the findings for the strategic partnership between the AU and the UN. 相似文献
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Linnéa Gelot 《Contemporary Security Policy》2017,38(1):161-173
This article explores how the protection of civilians is being militarized by African policymakers and diplomats. I draw on practice approaches to analyze what social groups are doing when they claim to “protect civilians.” I show how innovative protection mechanisms can be seen as a function of officials and diplomats coping with the changing circumstances of increasingly militarized politics in Africa. Specifically, accountability mechanisms for unintended and intended civilian harm by African security operations have originated in connection with this development. I argue that these are results of anchoring practices, which means that everyday informal interactions in one context become linked to another context. I argue that these emerging accountability mechanisms represent a new combination of practices, with the potential of changing the routine activities and mutual learning between policymakers and diplomats. 相似文献
27.
Goodness C. Aye Mehmet Balcilar Rangan Gupta Reneé van Eyden 《Defence and Peace Economics》2014,25(6):619-633
This paper contributes to the growing literature on the milex-growth nexus, by providing a case study of South Africa and considering the possibility of structural breaks by applying newly developed econometric methods. Using full sample bootstrap Granger non-causality tests, no Granger causal link is found between military expenditure and GDP for 1951–2010, but parameter instability tests show the estimated VARs to be unstable. Using a bootstrap rolling window estimation procedure, however, finds evidence of bidirectional Granger causality in various subsamples. This implies standard Granger non-causality tests, which neither account for structural breaks nor time variation may be invalid. 相似文献
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