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11.
Emmanuel Terkimbi Akov 《African Security Review》2017,26(3):288-307
The resource debate is easily discerned as part of the ongoing history of farmer–herdsman conflict in the North Central region of Nigeria. Scarcity theorists are adept at linking scarcity with the onset of livelihood conflict while on the other hand resource abundance pundits insist it is profusion and not scarcity that impels conflict. This article traverses these wrangles and proceeds to downplay the resource polemic altogether. It is proposed that the resource debate, despite its profoundness, presents a narrow reading of farmer–herdsman clashes in Nigeria’s North Central region. It is suggested that a number of other factors, including elite land grabbing, ethno-religious identity construction, weak state capabilities, the citizenship question, corrupt traditional institutions, the lack of an effective land tenure system and a widespread culture of impunity, make for better readings of the conflict. Owing to the negative impacts of the conflict on state and society, it is recommended that the state in Nigeria should commit itself to addressing the citizenship question, strengthening the capabilities of security institutions, extirpating the culture of impunity and revaluing its policy on land redistribution. 相似文献
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Natural resources have been blamed for inducing slow growth and sparking civil conflicts and violence. This paper first develops a model to account for the hazard of armed civil conflicts as a manifestation of the natural resource curse, which is mediated by the quality of both economic and political institutions. We then use recently published data on institutional quality and natural resource rents to measure the potential impact of the resource curse on violent civil conflicts using a panel of data for over 100 countries in the period 1970–2010. Our model explicitly accounts for the role of good economic and political institutions in deterring the recourse to violence as well as the extent to which they might weaken the resource rents effect. 相似文献
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We consider the problem of scheduling a set of n jobs on a single batch machine, where several jobs can be processed simultaneously. Each job j has a processing time pj and a size sj. All jobs are available for processing at time 0. The batch machine has a capacity D. Several jobs can be batched together and processed simultaneously, provided that the total size of the jobs in the batch does not exceed D. The processing time of a batch is the largest processing time among all jobs in the batch. There is a single vehicle available for delivery of the finished products to the customer, and the vehicle has capacity K. We assume that K = rD, where and r is an integer. The travel time of the vehicle is T; that is, T is the time from the manufacturer to the customer. Our goal is to find a schedule of the jobs and a delivery plan so that the service span is minimized, where the service span is the time that the last job is delivered to the customer. We show that if the jobs have identical sizes, then we can find a schedule and delivery plan in time such that the service span is minimum. If the jobs have identical processing times, then we can find a schedule and delivery plan in time such that the service span is asymptotically at most 11/9 times the optimal service span. When the jobs have arbitrary processing times and arbitrary sizes, then we can find a schedule and delivery plan in time such that the service span is asymptotically at most twice the optimal service span. We also derive upper bounds of the absolute worst‐case ratios in both cases. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 470–482, 2015 相似文献
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Sheldon M. Ross 《海军后勤学研究》2015,62(8):659-663
There are n customers that need to be served. Customer i will only wait in queue for an exponentially distributed time with rate λi before departing the system. The service time of customer i has distribution Fi, and on completion of service of customer i a positive reward ri is earned. There is a single server and the problem is to choose, after each service completion, which currently in queue customer to serve next so as to maximize the expected total return. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 659–663, 2015 相似文献
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郭文永 《中国人民武装警察部队学院学报》2014,(7):94-96
阐述了边消警文献信息资源保障体系建设的内涵和建设原则,从资源体系建设、服务体系建设、网络平台建设和保障体系建设等四方面对边消警文献信息资源保障体系建设的内容进行了探讨. 相似文献
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In scheduling problems with two competing agents, each one of the agents has his own set of jobs to be processed and his own objective function, and both share a common processor. In the single‐machine problem studied in this article, the goal is to find a joint schedule that minimizes the total deviation of the job completion times of the first agent from a common due‐date, subject to an upper bound on the maximum deviation of job completion times of the second agent. The problem is shown to be NP‐hard even for a nonrestrictive due‐date, and a pseudopolynomial dynamic program is introduced and tested numerically. For the case of a restrictive due‐date (a sufficiently small due‐date that may restrict the number of early jobs), a faster pseudopolynomial dynamic program is presented. We also study the multiagent case, which is proved to be strongly NP‐hard. A simple heuristic for this case is introduced, which is tested numerically against a lower bound, obtained by extending the dynamic programming algorithm. © 2013 Wiley Periodicals, Inc. Naval Research Logistics 61: 1–16, 2014 相似文献
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We consider the problem of scheduling a set of jobs on a single machine subject to random breakdowns. We focus on the preemptive‐repeat model, which addresses the situation where, if a machine breaks down during the processing of a job, the work done on the job prior to the breakdown is lost and the job will have to be started from the beginning again when the machine resumes its work. We allow that (i) the uptimes and downtimes of the machine follow general probability distributions, (ii) the breakdown process of the machine depends upon the job being processed, (iii) the processing times of the jobs are random variables following arbitrary distributions, and (iv) after a breakdown, the processing time of a job may either remain a same but unknown amount, or be resampled according to its probability distribution. We first derive the optimal policy for a class of problems under the criterion to maximize the expected discounted reward earned from completing all jobs. The result is then applied to further obtain the optimal policies for other due date‐related criteria. We also discuss a method to compute the moments and probability distributions of job completion times by using their Laplace transforms, which can convert a general stochastic scheduling problem to its deterministic equivalent. The weighted squared flowtime problem and the maintenance checkup and repair problem are analyzed as applications. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004 相似文献