Approximation algorithms for capacitated stochastic inventory systems with setup costs

We develop the first approximation algorithm with worst‐case performance guarantee for capacitated stochastic periodic‐review inventory systems with setup costs. The structure of the optimal control policy for such systems is extremely complicated, and indeed, only some partial characterization is available. Thus, finding provably near‐optimal control policies has been an open challenge. In this article, we construct computationally efficient approximate optimal policies for these systems whose demands can be nonstationary and/or correlated over time, and show that these policies have a worst‐case performance guarantee of 4. We demonstrate through extensive numerical studies that the policies empirically perform well, and they are significantly better than the theoretical worst‐case guarantees. We also extend the analyses and results to the case with batch ordering constraints, where the order size has to be an integer multiple of a base load. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 304–319, 2014     

Some comparisons of residual life of coherent systems with exchangeable components

Most of the research, on the study of the reliability properties of technical systems, assume that the components of the system operate independently. However, in real life situation, it is more reasonable to assume that there is dependency among the components of the system. In this article, we give sufficient conditions based on the signature and the joint distribution of component lifetimes to obtain stochastic ordering results for coherent and mixed systems with exchangeable components. Some stochastic orders on dynamic (or conditional) signature of coherent systems are also provided. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 549–556, 2014     

Experiment and simulation of launching process of a small-diameter steel cartridge case

In order to explore the rules of the deformation force during the launching of a small-diameter steel cartridge, the semi-closed bomb test method is used to test the greatest strains on chamber outer wall under the different chamber pressures. The pressure curves of cartridge chamber are measured in experiment, and the tensile test data of cartridge are loaded into the numerical calculation to compare with the experimental data. The conclusion was obtained that the calculated results match better with the experimental results by considering strain rate bilinear kinematic hardening material constitutive model. The forces on the various parts of the cartridge during launching and their deformation rules are achieved, in which the equivalent plastic strain decreases and the cylinder ring withstands the maximum equivalent stress when the cartridge case clings to the bore from the mouth to the bottom.     

基于DDS的虚拟信号发生器LabVIEW程序设计

针对传统信号发生器存在的成本高、功能单一、电子线路复杂等缺点,设计了一种基于频率合成技术的虚拟任意信号发生器。通过动态链接库(DLL)与下位机设备DDS-3X25进行通信,基于"模块化"和事件结构的设计思想,用LabVIEW编程实现了基本波形、任意波形、噪声叠加、波形数据载入、波形数据量化转换和线性插值等程序模块。实验结果表明,该设计不仅能产生纯净和叠加噪声的正弦波、方波、三角波和锯齿波等基本波形,而且可以输出手绘的任意波形,验证了设计的有效性。     

基于系统动力学的协同决策模型性能分析

为探索信息化作战中指挥控制关键因素,提出改进作战指挥体制的对策措施,采用系统动力学理论,对协同决策的结构、参与者和信息反馈关系等关键因素进行了分析,在此基础上构建了基于系统动力学的协同决策模型并进行了模拟仿真。结果表明,增加指挥控制机构之间的信息共享可以有效提升协同决策的效率,为建立协同决策指挥控制体制提供了借鉴意义。     

Dynamic institutionalization: the foundations of Japan’s radioactive problem

Many have suggested that the true purpose behind Japan’s development of a closed nuclear-fuel cycle is to maintain the technical potential to develop nuclear weapons. However, closer examination of the development of Japan’s nuclear industry shows that, although Japan possesses advanced nuclear technologies, there has been no deliberate strategy to create a nuclear-weapon option. There is no “nuclear hedge.” To illustrate this point, this article presents a framework called “dynamic institutionalization” to explain the origins of Japan’s nuclear policies and the different sets of institutionalized pressures and constraints that have perpetuated these policies over time. Japan’s continued development of closed fuel-cycle technologies is primarily driven by domestic politics and the lack of a permanent spent-fuel management solution. On the other hand, Japan’s institutionalized nuclear forbearance is driven by the calculation that, as long as US extended deterrence remains credible, Japan’s security is best guaranteed through reliance on the US nuclear umbrella. By analytically untangling the policy of closed fuel-cycle development from the rationale for nuclear forbearance, this article provides a more nuanced view of the relationships between the domestic and international variables shaping Japan’s nuclear policies.     

Machine scheduling with pickup and delivery

The coordination of production, supply, and distribution is an important issue in logistics and operations management. This paper develops and analyzes a single‐machine scheduling model that incorporates the scheduling of jobs and the pickup and delivery arrangements of the materials and finished jobs. In this model, there is a capacitated pickup and delivery vehicle that travels between the machine and the storage area, and the objective is to minimize the makespan of the schedule. The problem is strongly NP‐hard in general but is solvable in polynomial time when the job processing sequence is predetermined. An efficient heuristic is developed for the general problem. The effectiveness of the heuristic is studied both analytically and computationally. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005.     

基于PON技术的多站雷达数字光纤传输系统设计

提出一种多站雷达体系雷达数据光纤传输系统的方案设计和实现方法。与传统雷达使用的光纤传输系统不同,而是采用技术较新的基于无源光网络PON的实时数据通信系统,这是无源光网络技术在多传感器实时通信领域的首次应用。在系统设计中利用先进的光电子和在编程技术,实现了点对多点雷达数据光纤传输,提高了信号传输质量,同时系统具有动态接入和扩容的能力。     

射频识别系统的多目标识别-反碰撞算法

对多目标识别技术的二进制搜索算法、时隙ALOHA算法进行了剖析,并对ALOHA算法用概率论和数理统计的方法进行了深入的理论分析,得出要根据所设计的射频识别系统的特点合理采用各种算法方可得到良好的效果.该算法的实现对提高高速公路上自动收费系统、人员和物流管理等各领域的工作效率具有一定的指导意义.     

水下航行器动力定位下的运动轨迹设计与仿真

对远程低速水下航行器在动力定位系统作用下的运动进行了研究.远程低速水下航行器由于航程远必须采用GPS全球导航定位系统进行导航,于是水下航行器就必须具有动力定位的能力,使之可以在需要GPS导航的时候上浮到近水面,导航完成后再下潜回航行深度.在建立水下航行器运动数学模型及进行推力分配的基础上,对远程低速水下航行器的典型运动轨迹进行了仿真,并对仿真结果进行了分析.