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71.
72.
随着新航线的开辟和新飞机的投入使用,航空公司的任务量急剧增长,飞行员需求的估计和机组的合理配置变得日益重要。本文基于实际工作需求,提出一类用于评估飞行员数量,并进行机组均衡配置的整数规划模型,为航空公司进行飞行员的数量评估和任务分配提供决策支持。本文在以下两个方面做出改进:1)加入国际长途航线,研究国内短途航线和国际长途航线混合搭配情况下飞行员的配置问题;2)鉴于大型整数规划求解的复杂性,通过评估航空公司所需要的飞行员数量的下界,为决策人员制定中长期规划提供依据。本文通过启发式算法进行飞行员的配置,计算结果接近理论问题的下界,证明了算法的有效性。 相似文献
73.
Orthogonal frequency division multiplexing passive optical network (OFDM-PON) has been considered a promising access solution to meet the variable bandwidth demand. In this paper, a novel scheduling for dynamic bandwidth allocation (DBA) at medium access control (MAC) layer is proposed for uplink transmission of OFDM-PON. In order to utilize the bandwidth efficiently, scheduling in four dimensions is adopted in the proposed DBA algorithm. Four dimensions stand for frequency domains, time domains, modulation formats and power allocations. The algorithm is quite flexible. Simulation results and analysis show that the proposed algorithm can efficiently utilize the OFDM bandwidth and make the system highly energy-efficient. 相似文献
74.
Eva K. Lee Siddhartha Maheshwary Jacquelyn Mason William Glisson 《Annals of Operations Research》2006,148(1):25-53
A simulation and decision support system, RealOpt©, for planning large-scale emergency dispensing clinics to respond to biological threats and infectious disease outbreaks is described. The system allows public health administrators to investigate clinic design and staffing scenarios quickly. RealOpt© incorporates efficient optimization technology seamlessly interfaced with a simulation module. The system's correctness and computational advantage are validated via comparisons against simulation runs of the same model developed on a commercial system. Simulation studies to explore facility layout and staffing scenarios for smallpox vaccination and for an actual anthrax-treatment dispensing exercise and post event analysis are presented. The system produces results consistent with the model built on the commercial system, but requires only a fraction of the computational time. Each smallpox scenario runs within 1 CPU minute on RealOpt©, versus run times of over 5–10 h on the commercial system. The system's fast computational time enables its use in large-scale studies, in particular an anthrax response planning exercise involving a county with 864,000 households. The computational effort required for this exercise was roughly 30 min for all scenarios considered, demonstrating that RealOpt© offers a very promising avenue for pursuing a comprehensive investigation involving a more diverse set of scenarios, and justifying work towards development of a robust system that can be widely deployed for use by state, local, and tribal health practitioners. Using our staff allocation and assignments for the Anthrax field exercise, DeKalb county achieved the highest throughput among all counties that simultaneously conducted the same scale of Anthrax exercise at various locations, with labor usage at or below the other counties. Indeed, DeKalb exceeded the targeted number of households, and it processed 50% more individuals compared to the second place county. None of the other counties achieved the targeted number of households. The external evaluators commented that DeKalb produced the most efficient floor plan (with no path crossing), the most cost-effective dispensing (lowest labor/throughput value), and the smoothest operations (shortest average wait time, average queue length, equalized utilization rate). The study proves that even without historical data, using our system one can plan ahead and be able to wisely estimate the required labor resources. The exercise also revealed many areas that need attention during the operations planning and design of dispensing centers. The type of disaster being confronted (e.g., biological attack, infectious disease outbreak, or a natural disaster) also dictates different design considerations with respect to the dispensing clinic, facility locations, dispensing and backup strategies, and level of security protection. Depending on the situation, backup plans will be different, and the level of security and military personnel, as well as the number of healthcare workers required, will vary. In summary, the study shows that a real-time decision support system is viable through careful design of a stand-alone simulator coupled with powerful tailor-designed optimization solvers. The flexibility of performing empirical tests quickly means the system is amenable for use in training and preparation, and for strategic planning before and during an emergency situation. The system facilitates analysis of “what-if'' scenarios, and serves as an invaluable tool for operational planning and dynamic on-the-fly reconfigurations of large-scale emergency dispensing clinics. It also allows for “virtual field exercises” to be performed on the decision support system, offering insight into operations flow and bottlenecks when mass dispensing is required for a region with a large population. The system, designed in modular form with a flexible implementation, enables future expansion and modification regarding emergency center design with respect to treatment for different biological threats or disease outbreaks. Working with emergency response departments, further fine-tuning and development of the system will be made to address different biological attacks and infectious disease outbreaks, and to ensure its practicality and usability. 相似文献
75.
就具有最简单结构的抽象垄断服务系统的基本特性及其公共损耗的费用分摊问题建立了较为完整的公平性与合理性公理体系.同时,利用边际损耗原则导出了一类满足公理组的费用分摊方法,并将所得结论应用于电力系统有功网损费用分摊问题,从理论上统一了现有的几类主要的分摊方法.分析结论表明:损耗结构分析和费用分摊原则的确定在本质上从属于不同层次的问题.特别地,对不分明损耗而言:它们还是不可分割的统一体.对这一类问题进行描述必须考虑综合运用数学、社会学、经济学和方法论原则. 相似文献
76.
This paper considers the discrete two-hub location problem. We need to choose two hubs from a set of nodes. The remaining nodes are to be connected to one of the two hubs which act as switching points for internodal flows. A configuration which minimizes the total flow cost needs to be found. We show that the problem can be solved in polynomial time when the hub locations are fixed. Since there are at most
ways to choose the hub locations, the two-hub location problem can be solved in polynomial time. We transform the quadratic 0–1 integer program of the single allocation problem in the fixed two-hub system into a linear program and show that all extreme points of the polytope defined by the LP are integral. Also, the problem can be transformed into a minimum cut problem which can be solved efficiently by any polynomial time algorithm. 相似文献
77.
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
78.
运筹学中有很多离散规划问题。其中的线性规划通常用分枝定界法或割平面法,还有图上作业法求解。不论哪种方法工作量都不小,而且效率低;至于非线性规划大都是用动态规划法求解,也很麻烦、耗时。对于大规模问题,不论线性或非线性离散规划,现有解法都受到问题规模的限制;还有资源分配和背包问题至今没有见到解决方法。本文就是为了解决这些问题,提出了相对差分搜索算法。通过5个算例和其它文献中的一些算例计算验证了本法简单、快速、有效和精确,尤其不受问题规模的限制是其最大的优点。 相似文献
79.
本文针对一类设备的最优分配问题,将利润表转化为边际利润表,并建立了相应的寻优方程,通过实例说明,在一定情况下,用改进后的算法比常规算法节省一定的计算工作量. 相似文献
80.
A tabu search procedure for multicommodity location/allocation with balancing requirements 总被引:2,自引:0,他引:2
Teodor G. Crainic Michel Gendreau Patrick Soriano Michel Toulouse 《Annals of Operations Research》1993,41(4):359-383
We propose a tabu search heuristic for the location/allocation problem with balancing requirements. This problem typically arises in the context of the medium term management of a fleet of containers of multiple types, where container depots have to be selected, the assignment of customers to depots has to be established for each type of container, and the interdepot container traffic has to be planned to account for differences in supplies and demands in various zones of the geographical territory served by a container shipping company. It is modeled as a mixed integer program, which combines zero-one location variables and a multicommodity network flow structure. Extensive computational results on a set of benchmark problems and comparisons with an efficient dual ascent procedure are reported. These show that tabu search is a competitive approach for this class of problems. 相似文献