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11.
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   
12.
In this article, we study a two‐level lot‐sizing problem with supplier selection (LSS), which is an NP‐hard problem arising in different production planning and supply chain management applications. After presenting various formulations for LSS, and computationally comparing their strengths, we explore the polyhedral structure of one of these formulations. For this formulation, we derive several families of strong valid inequalities, and provide conditions under which they are facet‐defining. We show numerically that incorporating these valid inequalities within a branch‐and‐cut framework leads to significant improvements in computation. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 647–666, 2017  相似文献   
13.
We study the environmental regulation of industrial activities that are organized as projects. Applications arise in construction, ship and aircraft building, and film making, among other industries. Relative to manufacturing, environmental regulation is different in project‐based industries, due to the uniqueness and geographical diversity of projects, and a lack of product takeback programs. Because the amount of waste and pollution generated by project companies can be large, regulators need environmental policies to ensure reduction of waste and pollution. We consider a regulator who attempts to maximize social welfare. We model this problem as a bilevel nonlinear program. The upper level regulator specifies waste reduction targets, which the lower level project companies meet using waste stream reduction and remediation of pollution, while attempting to control their project costs. We find that high waste diversion targets lead to outcomes with little pollution, but excessive project costs and only modest waste stream reduction. Projects that have lower task precedence density, or that have pollutants with different environmental impacts, show larger increases in project cost and time resulting from regulation. We describe a subsidy for waste stream reduction that coordinates the system, and we estimate the value of coordination. We also describe a bonus that encourages truthful reporting by project companies, and evaluate the relative cost and effectiveness of the subsidy and the bonus. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 228–247, 2015  相似文献   
14.
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   
15.
In the last decade, there has been much progress in understanding scheduling problems in which selfish jobs aim to minimize their individual completion time. Most of this work has focused on makespan minimization as social objective. In contrast, we consider as social cost the total weighted completion time, that is, the sum of the agent costs, a standard definition of welfare in economics. In our setting, jobs are processed on restricted uniform parallel machines, where each machine has a speed and is only capable of processing a subset of jobs; a job's cost is its weighted completion time; and each machine sequences its jobs in weighted shortest processing time (WSPT) order. Whereas for the makespan social cost the price of anarchy is not bounded by a constant in most environments, we show that for our minsum social objective the price of anarchy is bounded above by a small constant, independent of the instance. Specifically, we show that the price of anarchy is exactly 2 for the class of unit jobs, unit speed instances where the finite processing time values define the edge set of a forest with the machines as nodes. For the general case of mixed job strategies and restricted uniform machines, we prove that the price of anarchy equals 4. From a classical machine scheduling perspective, our results establish the same constant performance guarantees for WSPT list scheduling. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012  相似文献   
16.
As Canada's military mission in Afghanistan winds down and the country faces several years of fiscal austerity, all of Canada's major political parties are agreed that Canadian defence budgets must stay level or be cut. This comes at a time when the defence department is slated to replace the Canadian Forces’ (CF) major equipment fleets. Canada's defence establishment thus faces some critical decisions. One option is to try to maintain its expeditionary capabilities across all three services: army, navy and air force. Absent substantial new infusions of funds, however, this approach is likely to lead to an overall and largely chaotic reduction of capabilities. Another option is to make some difficult choices as to which expeditionary capabilities to maintain as part of a strategic review of Canada's future military needs. Such an option would ensure that Canada has at least some military capacities which can reliably be devoted to the most demanding international operations, while maintaining those capabilities required for domestic duties and North American defence. Pursuing this option would accord with the new North Atlantic Treaty Organization Strategic Concept and the call for “Smart Defense” within the Alliance. This article assesses the arguments for and against the option of specialising Canada's future defence capabilities and explores scenarios as to what a future CF may look like.  相似文献   
17.
Psychological warfare had been used by the French army in the Indochina War (1946–54), and had spawned a sub-caste of French officers who moulded it and counter-insurgent propaganda into a doctrine known as guerre révolutionnaire (revolutionary war). In Algeria, in 1956, the army established a specialist training centre, the CIPCG, at Arzew on the Algerian coast, to provide courses for all officers arriving ‘in country’. By this, the French command sought to ensure that field officers possessed an approach to pacification and the political dimension to their missions well suited to the terrain and socio-political make-up of Algeria. The real ‘revolutionary war’ zealots were kept away from the directing staff, although some delivered guest lectures. Despite complaints from commanders of field units at losing experienced officers to the CIPCG instructing staff, Arzew students testified that the courses aided them in their missions. Some 10,000 French officers undertook courses at the CIPCG before it was downgraded and then disbanded after Pierre Messmer, a Gaullist, became Minister for the Armed Forces in 1960.  相似文献   
18.
This essay provides an overview of the eras of Mexican cinema followed by an analysis of 10 Spanish-language narco cinematic representations, an overview of the eras of American cinema followed by an analysis of 10 English language narco cinematic representations, and a conclusion that compares and contrasts the Mexican and US narco war cinematic experience. Due to divergent national trajectories – Mexico is engulfed in narco violence and corruption while the United States is not – more differences than similarities exist between these national cinematic genres. Dark spirituality themes are also increasingly evident in more recent narco war films.  相似文献   
19.
Budgetary restrictions resulting from the present international economic crisis have tightened the need to improve efficiency in defense spending, leading to the armed forces having to undertake their duties with fewer resources. Previous reports on the subject have looked into the determining factors and effects of military spending but very few studies have analyzed the determinants for the modernization of the methodology for assessing efficiency. Thus, using a multiple regression statistical model, we have analyzed the appraisal systems in place in 28 countries to identify factors that influence the development of economic assessment of military expenditure. Our findings have revealed three factors that may favor the improvement of appraisal systems with regard to military expenditure: the quality of governance, size of the armed forces, and unemployment levels.  相似文献   
20.
This article analyses the economic impact of the expenditure budget of the Spanish Ministry of Defence (MoD) and its Autonomous Agencies (AA), distinguishing direct, indirect and induced effects. The input–output methodology is used to find intersectoral effects on the rest of the economy. The article quantifies the economic impact in terms of production, gross value added (GVA), employed population, tax revenue, and also in terms of its contribution to the gross domestic product (GDP) of Spain in 2010. The results show that the activity of the MoD and AA generates 1.2% of the country’s GDP and 1.7% of total employment in that year.  相似文献   
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