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排序方式: 共有491条查询结果,搜索用时 46 毫秒
51.
本文根据道路灾害事故的发生特点,对城市路桥养护系统的运行模式和资源的合理调用机理进行分析,考虑到事发地点潜在的资源需求概率,建立资源布局的混合整数规划模型.本模型中资源布局方案的调度决策基础是在灾害事故的资源需求不发生变化的条件下,使得每个救助点的资源同时部分地为辖区内现有事故和潜在事故服务,而现有事故的剩余需求由其他救助点派出资源来满足.该模型的目标是解决城市中因同一时间段内发生两起灾害事故而造成路桥破坏导致的救助资源短缺问题,同时避免资源的闲置浪费.最后,通过算例证明,本方法较通常方法对城市总的资源配置量大大减少. 相似文献
52.
区域水资源承载力模糊线性规划模型及应用 总被引:1,自引:0,他引:1
凌和良 《数学的实践与认识》2008,38(24)
首先按照联合国教科文组织提出的资源承载力定义,给出水资源承载力的定义,建立了水资源承载力的模糊线性规划模型,然后运用这模型对江西省的近期水资源承载力问题进行研究,数据结果表明模型的应用是成功的. 相似文献
53.
浙江省是全国岛屿最多的省份,海岛为全省实现“海洋经济大省”起着重要作用。本文在分析浙江省海岛土地利用现状及其特点的基础上,指出开发利用中存在的主要问题,提出了合理开发利用的战略对策。 相似文献
54.
Jeffrey A. Krautkraemer 《Natural Resource Modeling》1988,2(3):421-437
This paper examines the relationship between the rate of discount and the the optimal level of permanently preserved natural environments. A lower rate of discount increases the demand for both preserved environments and capital accumulation. The greater demand for capital indirectly increases the demand for the productive resource inputs found within the natural environments thereby reducing the level of preservation. This indirect effect outweighs the direct effect of the rate of discount on the level of preservation if the elasticity of output with respect to capital is greater that the elasticity of output with respect to the resource input. In general, the asymptotic values of the output elasticities depend upon the rate of discount and so there can be a nonmonotonic relationship between the rate of discount and the optimal level of permanently preserved natural environments. 相似文献
55.
56.
研究带凸资源和恶化效应的单机窗口指派排序问题,其中窗口指的是松弛窗口,凸资源和恶化效应指的是工件的实际加工时间是其开始加工时间的线性函数,是其资源消耗量的凸函数。目标是确定工件的加工顺序,资源分配量以及窗口的开始加工时间和长度使其在总资源消耗费用(与窗口有关的排序费用)有上界限制的条件下,极小化与窗口有关的排序费用(总资源消耗费用)。获得了求解上述问题的最优算法,证明了该问题是多项式时间可解的。 相似文献
57.
The objective of this study is to generate an optimal surgery schedule of elective surgery patients with uncertain surgery operations, which includes uncertainty in surgery durations and the availability of downstream resources such as surgical intensive care unit (SICU) over multi-periods. The stochastic optimization is adapted and the sample average approximation (SAA) method is proposed for obtaining an optimal surgery schedule with respect to minimizing the total cost of patient costs and overtime costs. A computational experiment is presented to evaluate the performance of the proposed method. 相似文献
58.
An exact algorithm for a vehicle routing problem with time windows and multiple use of vehicles 总被引:2,自引:0,他引:2
Nabila Azi Michel Gendreau Jean-Yves Potvin 《European Journal of Operational Research》2010,202(3):756-763
The vehicle routing problem with multiple use of vehicles is a variant of the classical vehicle routing problem. It arises when each vehicle performs several routes during the workday due to strict time limits on route duration (e.g., when perishable goods are transported). The routes are defined over customers with a revenue, a demand and a time window. Given a fixed-size fleet of vehicles, it might not be possible to serve all customers. Thus, the customers must be chosen based on their associated revenue minus the traveling cost to reach them. We introduce a branch-and-price approach to address this problem where lower bounds are computed by solving the linear programming relaxation of a set packing formulation, using column generation. The pricing subproblems are elementary shortest path problems with resource constraints. Computational results are reported on euclidean problems derived from well-known benchmark instances for the vehicle routing problem with time windows. 相似文献
59.
针对网格环境的自治性、动态性、分布性和异构性等特征.提出基于多智能体系统(Mutil Agent System,MAS)博弈协作的资源动态分配和任务调度模型,建立了能够反映供求关系的网格资源调度模型和任务求解算法,证明了资源分配博弈中Nash均衡点的存在性、唯一性和Nash均衡解,该方法能够利用消费者agent的学习和协商能力,考虑和引入消费者的心理行为,使得消费者的资源申请和任务调度具有较高的合理性和有效性.实验结果表明,资源调度算法不但可以有效减少不必要的延迟,而且在响应时间的平滑性、吞吐率及资源利用率方面比传统算法要好,从而使得整个资源的供需合理、负载均衡. 相似文献
60.
B. Bräutigam B. Vogel R. Gellermann 《Isotopes in environmental and health studies》2013,49(3):287-292
Abstract Since the 1960s intensive isotope hydrogeological studies have been carried out in the Finne mountain range between Herrengosserstedt in Thuringia and the River Unstrut near Karsdorf in Saxony-Anhalt. The new railway line Erfurt-Leipzig/Halle, a part of the traffic projects German Union - Railway-No. 8-, will cross this area with two tunnels, each of which is 6 km long. The tunnelling of the Middle Bunter rocks on the west side involves the crossing of an area with deep wells used for drinking water supply. To clarify the hydrodynamic situation in this area, the planning company for railway construction German Union (PB DE) contracted Trischler und Partner to carry out an extensive exploration programme. This programme included not only investigations using the isotopes 2H, 18O, 3H, 13C and 14C, but also single measurements of chlorofluorocarbons (CFC) and a multitude of hydrochemical analyses. Because of stratum related ground water sampling, an aquifer related evaluation of the investigation results was possible. Based on these results a fundamentally new structural-geological model for the investigation area was developed. In addition to its great importance for the tunnel planning, with the new model it will be possible to solve urgent questions concerning the drinking water supply in this region. 相似文献