A two‐echelon inventory‐location problem with service considerations

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     

Approximation algorithms for general one‐warehouse multi‐retailer systems

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     

Optimal design of a novel cylindrical sandwich panel with double arrow auxetic core under air blast loading

The increasing threat of explosions on the battle field and the terrorist action requires the development of more effective blast resistance materials and structures. Curved structure can support the external loads effectively by virtue of their spatial curvature. In review of the excellent energy absorption property of auxetic structure, employing auxetic structure as core material in curved sandwich shows the potential to improve the protection performance. In this study, a novel cylindrical sandwich panel with double arrow auxetic (DAA) core was designed and the numerical model was built by ABAQUS. Due to the complexity of the structure, systematic parameter study and optimal design are conducted. Two cases of optimal design were considered, case1 focuses on reducing the deflection and mass of the structure, while case2 focuses on reducing the deflection and increasing the energy absorption per unit mass. Parameter study and optimal design were conducted based on Latin Hypercube Sampling (LHD) method, artificial neural networks (ANN) metamodel and the nondominated sorting genetic algorithm (NSGA-Ⅱ). The Pareto front was obtained and the cylindrical DAA structure performed much better than its equal solid panel in both blast resistance and energy absorption capacity. Optimization results can be used as a reference for different applications.     

应急净水系统作业性能试验研究

用应急净水系统净化不同水质的原水，以考察其作业性能。结果表明，出水浊度不受原水浊度的影响，且低于1NTU；在试验原水浊度、温度范围内，出水流量较稳定，产水量符合设计要求；出水水质符合生活饮用水卫生标准的要求。     

装备设计中的再制造性指标预计方法

再制造性设计是装备再制造工程的重要组成部分,是实现退役装备易于再制造的可靠保证,再制造性指标预计是再制造性设计的重要内容。探讨了再制造性指标预计的相关概念及其再制造性指标预计程序,并综合提出了几种可行的再制造性指标预计方法,可为装备的再制造性设计提供技术支撑。     

稀薄流气粒两相耦合作用的热力学模型

基于直接模拟Monte Carlo(DSMC)方法,从描述粒子微观运动层次出发,构造高空稀薄环境下气体一颗粒两相双向耦合作用的热力学模型,发展适用于稀薄流过渡区多相复杂流动的DSMC算法.通过算例验证,结果表明,此模型能够较好地反映相间动量和能量传输机制.     

以用户为中心的防空导弹武器系统人机界面设计研究

防空导弹武器系统不断更新换代，复杂功能和简单操作需求的矛盾成为设计过程中普遍存在的问题。为优化防空导弹武器系统人机界面设计，运用人机交互学中以用户为中心的设计和评估理论，对防空导弹武器系统人机界面设计进行研究。将设计过程分为用户与需求分析、设计、评估与改进三个阶段，给出了每个阶段的工作思路以及工作重点。将方法应用于某型防空导弹武器系统人机界面设计，有效地规范了设计流程，提高了设计水平。     

高校图案设计课程创新式教学的探索

本文着重介绍如何通过多种教学手法的创新与探索，从而培养学生对图案设计课程的兴趣，提高学生自主探究问题的能力和创造性思维。同时介绍多媒体技术在图案设计教学中的应用和方法，如何开发学生创新思维的方法和途径，以及多种创新式教学法使用的成效和注意事项。     

军事信息系统作战活动描述方法研究*

针对军事信息系统需求分析需要，探讨了作战活动过程描述、作战节点连接描述、节点状态转换描述和作战活动时序描述的内容和方法。基于该理论和方法，可以准确描述信息化条件下军事人员对军事信息系统的应用需求，实现军事人员与技术人员的有效沟通，为军事信息系统军事需求分析与应用设计的基础。     

组合式空调机组状态监测与故障诊断系统设计

组合式空调机组具有功能段组合灵活、技术参数可选范围大以及对目标环境指标操控性强等优点，广泛应用于导弹和卫星测试环境调控等军事领域。但是机组在运行过程中常出现风机风量不足、加热器加热不均以及除湿能力下降等问题，直接影响着机组性能的发挥。针对上述问题，以某基地某型空调机组为研究对象，设计了一套具有实时监测、在线评估、分段报警和故障诊断等功能的空调机组运行的状态监测与故障诊断系统，重点阐述了该系统的设计思路、硬件组成及软件框架。该系统在提高空调机组的性能监控、故障报警、故障诊断与隔离的能力及故障类型确定、故障部件的快速定位，为相关部门提供维修决策措施等方面具有实际意义。