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401.
分析了螺旋轮式管道检测机器人驱动系统的组成和原理,给出了管道机器人驱动电动机的控制策略,并设计了电动机的控制系统.根据机器人的运动参数分析管道状况,研究了驱动电动机的控制过程,为下一步精确控制管道机器人的驱动电动枳嵌供了参考. 相似文献
402.
We study the problem of designing a two‐echelon spare parts inventory system consisting of a central plant and a number of service centers each serving a set of customers with stochastic demand. Processing and storage capacities at both levels of facilities are limited. The manufacturing process is modeled as a queuing system at the plant. The goal is to optimize the base‐stock levels at both echelons, the location of service centers, and the allocation of customers to centers simultaneously, subject to service constraints. A mixed integer nonlinear programming model (MINLP) is formulated to minimize the total expected cost of the system. The problem is NP‐hard and a Lagrangian heuristic is proposed. We present computational results and discuss the trade‐off between cost and service. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009 相似文献
403.
Free riding in a multichannel supply chain occurs when one retail channel engages in the customer service activities necessary to sell a product, while another channel benefits from those activities by making the final sale. Although free riding is, in general, considered to have a negative impact on supply chain performance, certain recent industry practices suggest an opposite view: a manufacturer may purposely induce free riding by setting up a high‐cost, customer service‐oriented direct store to allow consumers to experience the product, anticipating their purchase at a retail store. This article examines how the free riding phenomenon affects a manufacturer's supply chain structure decision when there are fixed plus incremental variable costs for operating the direct store. We consider factors such as the effort required to find and buy the product at a retail store after visiting the direct store, the existence of competing products in the market, and the extent of consumer need to obtain direct‐store service. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
404.
Logistical planning problems are complicated in practice because planners have to deal with the challenges of demand planning and supply replenishment, while taking into account the issues of (i) inventory perishability and storage charges, (ii) management of backlog and/or lost sales, and (iii) cost saving opportunities due to economies of scale in order replenishment and transportation. It is therefore not surprising that many logistical planning problems are computationally difficult, and finding a good solution to these problems necessitates the development of many ad hoc algorithmic procedures to address various features of the planning problems. In this article, we identify simple conditions and structural properties associated with these logistical planning problems in which the warehouse is managed as a cross‐docking facility. Despite the nonlinear cost structures in the problems, we show that a solution that is within ε‐optimality can be obtained by solving a related piece‐wise linear concave cost multi‐commodity network flow problem. An immediate consequence of this result is that certain classes of logistical planning problems can be approximated by a factor of (1 + ε) in polynomial time. This significantly improves upon the results found in literature for these classes of problems. We also show that the piece‐wise linear concave cost network flow problem can be approximated to within a logarithmic factor via a large scale linear programming relaxation. We use polymatroidal constraints to capture the piece‐wise concavity feature of the cost functions. This gives rise to a unified and generic LP‐based approach for a large class of complicated logistical planning problems. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009 相似文献
405.
406.
诚信对于提升整个社会道德水平,促进经济社会发展,具有重要的作用,对新疆大学生这一群体更有着重要的意义。本文对新疆大学生诚信观进行问卷调查,通过对调查数据的统计分析,发现大学生表现出新的诚信观,并提出了树立大学生正确诚信观的对策。 相似文献
407.
一种基于ANSYS的舰船静电场分析方法 总被引:1,自引:0,他引:1
基于ANSYS有限元软件,建立了舰船的3-D有限元模型。利用TREFFTZ方法对舰船模型进行了分析,得到了舰船在周围海水中形成的静电场分布状况。对比仿真结果与实验结果,验证了基于ANSYS的舰船静电场分析方法的正确性和有效性,并对仿真的电场云图进行了分析,所获得的结果为消除舰船静电场奠定了基础。 相似文献
408.
本文基于我国RFID技术发展、标准及应用现状,研究我国物联网发展对RFID技术发展的影响,提出了在完善标准、发展超高频技术、物联网试点应用等方面开展应用研究的建议。 相似文献
409.
1998~2008年,是我国国防科技工业取得辉煌成就的10年,也是国防科技成果推广转化工作取得较快发展的10年,本文简要概括了10年来成果推广转化工作情况,并对新时期成果推广转化工作提出了建议。 相似文献
410.
针对目前雷达模拟器不能满足雷达组网系统调试与模拟测试需求的问题,在分析雷达组网系统测试信息源功能需求的基础上,采用纯软件的实现方法,从体系结构、功能模块和信息流3个方面对系统进行了详细的设计,讨论分析了具体技术实现中的几个关键问题,给出了具体的仿真实例。系统测试结果验证了设计的合理性,该设计满足了雷达组网系统测试对目标和雷达控制灵活性等多方面的需求。 相似文献