首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   226篇
  免费   44篇
  国内免费   8篇
  2022年   3篇
  2021年   1篇
  2020年   4篇
  2019年   6篇
  2018年   2篇
  2017年   5篇
  2016年   8篇
  2015年   9篇
  2014年   13篇
  2013年   11篇
  2012年   14篇
  2011年   13篇
  2010年   14篇
  2009年   20篇
  2008年   19篇
  2007年   23篇
  2006年   22篇
  2005年   13篇
  2004年   17篇
  2003年   7篇
  2002年   8篇
  2001年   7篇
  2000年   6篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
  1996年   6篇
  1995年   5篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   3篇
  1990年   4篇
  1989年   2篇
排序方式: 共有278条查询结果,搜索用时 15 毫秒
61.
r个物品分配到n个盒子中,在不同的条件下会有不同的分法数。本文讨论了不同条件下,分法数的计算方法。  相似文献   
62.
针对互补问题提出了一种无SLC限制的内点算法,仅要求线性函数F(x)=Hx q中的F是一个P*(τ)函数,不需要满足范数Lipschitz条件.并对该算法的全局收敛性做了证明。  相似文献   
63.
公安派出所应在辖区内进行消防监督检查是法定职能之一,也是加强社会消防安全监督检查,提高社会防御火灾事故能力,全面实现消防工作社会化的一条有效途径,它对弥补消防监督警力不足有着重要意义。分析目前派出所消防监督管理工作面临的问题,提出了改进和加强派出所消防监督管理工作的措施。  相似文献   
64.
消防部队基层干部面临个体需求与现实满足存在较大差距时出现的心理问题,受个体与周围环境因素的影响。面对心理问题,在重视部队传统教育的基础上,大胆借鉴现代企业管理经验和理念,充分利用压力的正效应,结合物质鼓励和精神激励,合理疏导,妥善处理。  相似文献   
65.
卫星数传调度模型研究   总被引:4,自引:2,他引:2       下载免费PDF全文
卫星数传调度问题是一个具有多时间窗口、多资源约束的优化问题。针对该问题,建立了卫星数传需求模型、任务模型和调度模型。在建模过程中,采用了框架模型形式,把问题中的主要约束封闭于每个数传任务中,这在降低调度模型复杂度的同时,也降低了调度算法设计难度。还提出了调度算法设计思想,并设计了一基于灵活度的调度算法。仿真表明,所建立的模型及算法对解决卫星数传调度问题是可行的。  相似文献   
66.
Many logistics systems operate in a decentralized way, while most optimization models assume a centralized planner. One example of a decentralized system is in some sea cargo companies: sales agents, who share ship capacity on a network, independently accept cargo from their location and contribute to the revenue of the system. The central headquarters does not directly control the agents' decisions but can influence them through system design and incentives. In this paper, we model the firm's problem to determine the best capacity allocation to the agents such that system revenue is maximized. In the special case of a single‐route, we formulate the problem as a mixed integer program incorporating the optimal agent behavior. For the NP‐hard multiple‐route case, we propose several heuristics for the problem. Computational experiments show that the decentralized system generally performs worse when network capacity is tight and that the heuristics perform reasonably well. We show that the decentralized system may perform arbitrarily worse than the centralized system when the number of locations goes to infinity, although the choice of sales incentive impacts the performance. We develop an upper bound for the decentralized system, where the bound gives insight on the performance of the heuristics in large systems. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007  相似文献   
67.
本文引入带权的 Sobolev 空间,讨论了奇型线性问题:(?)((?)u)/((?)t)-1/x~(?)(x~aa(x)u′)′=f(t,x) (x,t)∈1×J(?)/((?)x)u(t,0)=u(t,1)=0 t∈Ju(0,x)=φ(x) x∈I式中 I=(0,1),J=[0,T],0<α<3的有限元方法,并在适当条件下,给出了最佳估计:‖u_(?)-u‖_(0,2,a)≤ch~2{‖φ‖_(2,2,a)+[integral 0 to t (‖u‖~2_(2,2,a)+‖u_(?)‖~2_(2,2,a)dt]~(1/2)}‖u_(?)-u‖_(1,2,a)≤ch~2{‖φ‖_(2,2,a)+[integral 0 to t (‖u‖~2_(2,2,a)+‖u_(?)‖~2_(2,2,a)dt]~(1/2)}  相似文献   
68.
In this article, we introduce the capacitated warehouse location model with risk pooling (CLMRP), which captures the interdependence between capacity issues and the inventory management at the warehouses. The CLMRP models a logistics system in which a single plant ships one type of product to a set of retailers, each with an uncertain demand. Warehouses serve as the direct intermediary between the plant and the retailers for the shipment of the product and also retain safety stock to provide appropriate service levels to the retailers. The CLMRP minimizes the sum of the fixed facility location, transportation, and inventory carrying costs. The model simultaneously determines warehouse locations, shipment sizes from the plant to the warehouses, the working inventory, and safety stock levels at the warehouses and the assignment of retailers to the warehouses. The costs at each warehouse exhibit initially economies of scale and then an exponential increase due to the capacity limitations. We show that this problem can be formulated as a nonlinear integer program in which the objective function is neither concave nor convex. A Lagrangian relaxation solution algorithm is proposed. The Lagrangian subproblem is also a nonlinear integer program. An efficient algorithm is developed for the linear relaxation of this subproblem. The Lagrangian relaxation algorithm provides near‐optimal solutions with reasonable computational requirements for large problem instances. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008  相似文献   
69.
We study a single batching machine scheduling problem with transportation and deterioration considerations arising from steel production. A set of jobs are transported, one at a time, by a vehicle from a holding area to the single batching machine. The machine can process several jobs simultaneously as a batch. The processing time of a job will increase if the duration from the time leaving the holding area to the start of its processing exceeds a given threshold. The time needed to process a batch is the longest of the job processing times in the batch. The problem is to determine the job sequence for transportation and the job batching for processing so as to minimize the makespan and the number of batches. We study four variations (P1, P2, P3, P4) of the problem with different treatments of the two criteria. We prove that all the four variations are strongly NP‐hard and further develop polynomial time algorithms for their special cases. For each of the first three variations, we propose a heuristic algorithm and analyze its worst‐case performance. For P4, which is to find the Pareto frontier, we provide a heuristic algorithm and an exact algorithm based on branch and bound. Computational experiments show that all the heuristic algorithms perform well on randomly generated problem instances, and the exact algorithm for P4 can obtain Pareto optimal schedules for small‐scale instances. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 269–285, 2014  相似文献   
70.
We consider the burglar problem in which a burglar can either retire or choose among different types of burglaries, with each type having its own success probability and reward distribution. Some general structural results are established and, in the case of exponentially distributed reward distributions, a solution technique is presented. The burglar problem's relationship to a stochastic knapsack problem with a random exponentially distributed knapsack capacity is shown. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 359–364, 2014  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号