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601.
The National Football League (NFL) in the United States expanded to 32 teams in 2002 with the addition of a team in Houston. At that point, the league was realigned into eight divisions, each containing four teams. We describe a branch‐and‐cut algorithm for minimizing the sum of intradivisional travel distances. We consider first the case where any team can be assigned to any division. We also consider imposing restrictions, such as aligning the AFC (American Football Conference) and the NFC (National Football Conference) separately or maintaining traditional rivalries. We show that the alignment chosen by the NFL does not minimize the sum of intradivisional travel distances, but that it is close to optimal for an alignment that aligns the NFC and AFC separately and imposes some additional restrictions. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 683–701, 2003.  相似文献   
602.
This paper considers a two-agent scheduling problem with linear resource-dependent processing times, in which each agent has a set of jobs that compete with that of the other agent for the use of a common processing machine, and each agent aims to minimize the weighted number of its tardy jobs. To meet the due date requirements of the jobs of the two agents, additional amounts of a common resource, which may be in discrete or continuous quantities, can be allocated to the processing of the jobs to compress their processing durations. The actual processing time of a job is a linear function of the amount of the resource allocated to it. The objective is to determine the optimal job sequence and resource allocation strategy so as to minimize the weighted number of tardy jobs of one agent, while keeping the weighted number of tardy jobs of the other agent, and the total resource consumption cost within their respective predetermined limits. It is shown that the problem is -hard in the ordinary sense, and there does not exist a polynomial-time approximation algorithm with performance ratio unless ; however it admits a relaxed fully polynomial time approximation scheme. A proximal bundle algorithm based on Lagrangian relaxation is also presented to solve the problem approximately. To speed up convergence and produce sharp bounds, enhancement strategies including the design of a Tabu search algorithm and integration of a Lagrangian recovery heuristic into the algorithm are devised. Extensive numerical studies are conducted to assess the effectiveness and efficiency of the proposed algorithms.  相似文献   
603.
Accelerated degradation testing (ADT) is usually conducted under deterministic stresses such as constant‐stress, step‐stress, and cyclic‐stress. Based on ADT data, an ADT model is developed to predict reliability under normal (field) operating conditions. In engineering applications, the “standard” approach for reliability prediction assumes that the normal operating conditions are deterministic or simply uses the mean values of the stresses while ignoring their variability. Such an approach may lead to significant prediction errors. In this paper, we extend an ADT model obtained from constant‐stress ADT experiments to predict field reliability by considering the stress variations. A case study is provided to demonstrate the proposed statistical inference procedure. The accuracy of the procedure is verified by simulation using various distributions of field stresses. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006.  相似文献   
604.
Passenger prescreening is a critical component of aviation security systems. This paper introduces the Multilevel Allocation Problem (MAP), which models the screening of passengers and baggage in a multilevel aviation security system. A passenger is screened by one of several classes, each of which corresponds to a set of procedures using security screening devices, where passengers are differentiated by their perceived risk levels. Each class is defined in terms of its fixed cost (the overhead costs), its marginal cost (the additional cost to screen a passenger), and its security level. The objective of MAP is to assign each passenger to a class such that the total security is maximized subject to passenger assignments and budget constraints. This paper shows that MAP is NP‐hard and introduces a Greedy heuristic that obtains approximate solutions to MAP that use no more than two classes. Examples are constructed using data extracted from the Official Airline Guide. Analysis of the examples suggests that fewer security classes for passenger screening may be more effective and that using passenger risk information can lead to more effective security screening strategies. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006  相似文献   
605.
This article explains why Singapore, despite its small size and semi-authoritarian regime, retains one of the best military forces in the Indo-Pacific. It unpacks Singapore’s ability to continuously innovate since the 1960s – technologically, organizationally, and conceptually – and even recently joined the Revolution in Military Affairs bandwagon. Drawing from the broader military innovation studies literature, this article argues evolutionary peacetime military innovation is more likely to occur in a state with a unified civil–military relation and whose military faces a high-level diverse set of threats. This argument explains how the civil–military fusion under the People’s Action Party-led government since Singapore’s founding moment has been providing coherent and consistent strategic guidance, political support, and financial capital, allowing the Singapore Armed Forces to continuously innovate in response to high levels and diversity of threats.  相似文献   
606.
During the Cold War, the spread and fear of communism furnished the overarching ideological rationale for American foreign policy and for the deployment of United States military forces and resources. Subscribing to the domino theory and its potential impact on Southeast Asia, the Johnson Administration committed the United States to the Vietnam War. Following the September 11, 2001 attacks on the United States, and the commencement of the Global War on Terrorism, Washington once again set a national agenda rooted in a simplistic analysis reminiscent of Vietnam and the domino theory. Ignorant of Iraq’s mammoth sectarian, historical, ethnic, and global strategic complexities, the Bush Administration launched Operation Iraqi Freedom (OIF). The absence of critical analysis, contrarian viewpoints, and sound judgment characterized the US policy and strategy for both the Vietnam War and OIF, exhibiting the lack of moral courage that the national security enterprise seeks, but seldom attains. Faced with this challenge, this article draws attention to the ethical lessons we can learn from the dissent of William Fulbright and Andrew Bacevich.  相似文献   
607.
China’s rapid economic growth is facilitating massive increases in its military spending and causing increased security concerns in Asia and the Western Pacific. But there is uncertainty over how large China’s military spending is relative to other countries, or how fast it is growing in real terms. We address this issue by deriving a relative military cost price index based on the relative unit costs of inputs. We find that China’s real military spending is much larger than suggested by exchange rate comparisons, and even larger than standard purchasing power parity comparisons. We also find, however, that the real growth of China’s military spending has been smaller than conventionally thought. This is due to rapidly growing wages in China and the large share of personnel in China’s military budget.  相似文献   
608.
We investigate a single‐machine scheduling problem for which both the job processing times and due windows are decision variables to be determined by the decision maker. The job processing times are controllable as a linear or convex function of the amount of a common continuously divisible resource allocated to the jobs, where the resource allocated to the jobs can be used in discrete or continuous quantities. We use the common flow allowances due window assignment method to assign due windows to the jobs. We consider two performance criteria: (i) the total weighted number of early and tardy jobs plus the weighted due window assignment cost, and (ii) the resource consumption cost. For each resource consumption function, the objective is to minimize the first criterion, while keeping the value of the second criterion no greater than a given limit. We analyze the computational complexity, devise pseudo‐polynomial dynamic programming solution algorithms, and provide fully polynomial‐time approximation schemes and an enhanced volume algorithm to find high‐quality solutions quickly for the considered problems. We conduct extensive numerical studies to assess the performance of the algorithms. The computational results show that the proposed algorithms are very efficient in finding optimal or near‐optimal solutions. © 2017 Wiley Periodicals, Inc. Naval Research Logistics, 64: 41–63, 2017  相似文献   
609.
In this article, we consider a single machine scheduling problem, in which identical jobs are split into batches of bounded sizes. For each batch, it is allowed to produce less jobs than a given upper bound, that is, some jobs in a batch can be rejected, in which case a penalty is paid for each rejected job. The objective function is the sum of several components, including the sum of the completion times, total delivery cost, and total rejection cost. We reduce this problem to a min‐cost flow problem with a convex quadratic function and adapt Tamir's algorithm for its solution. © 2017 Wiley Periodicals, Inc. Naval Research Logistics 64: 217–224, 2017  相似文献   
610.
This contribution reflects on the state of strategic studies today and the criticism it has received in recent years, as being outdated and irrelevant. The authors formulate some premises for reinvigorating this field of inquiry by widening its scope and research agenda to do more justice to the wide variety of actors, perspectives and practices observable in the enterprise of strategy in our contemporary globalised world.  相似文献   
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