Lot streaming with supplier–manufacturer coordination

Lot splitting refers to breaking a production lot into smaller sublots during production. Coordinating lot splitting decisions across multiple stages of a production process is a challenging task. Traditional lot splitting and lot streaming models implicitly assume that the entire system is operated and owned by the same firm, or there exists a coordinator who controls the operation of all machines in the system. In this paper, we consider the situation where the machines in a multiple‐stage production process are owned and managed by different companies. Every item in a given production lot has to go through the processing by the supplier's machine, followed by the manufacturer's machine, and so on. We develop and analyze coordination mechanisms that enable different parties in the supply chain to coordinate their lot splitting decisions so as to achieve a systemwide optimum. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

餐厨垃圾热风干燥过程特性及模拟

为了考察不同温度(60～100℃)对2种餐厨垃圾在热风干燥过程中的水分变化规律及动理学特性的影响,利用7个数学模型对餐厨垃圾干燥过程的水分变化规律进行了拟合对比。结果表明:温度是影响干燥的重要因素。干燥温度越高,餐厨垃圾达到平衡含水率所需时间越短;烹饪过程可以改变餐厨垃圾的热阻,增加其活化能;用Page模型和Modified Page模型描述餐厨垃圾热风干燥过程拟合精度最佳;2种餐厨垃圾有效湿分扩散系数分别为1.37×10-9～2.47×10-9,5.14×10-10～2.05×10-9m2/s,活化能分别为13.86,34.05 kJ/mol。     

双色中波红外面目标成像特性差异分析

基于双色中波红外被动热探测过程,分两个阶段建立了面目标的双色中波红外图像形成模型,并对模型进行了仿真实验,得到了双色中波红外面目标图像在灰度值、目标受背景影响和目标背景对比度等3个方面存在的差异,通过实验图像的差异特征验证了这些成像特性差异存在的普遍性,为双色中波红外图像特征提取、融合规则和融合权重确定等提供了理论依据。     

紊流风场下无人机飞行状态多模型估计算法

针对紊流风场环境下飞行速度因模型参数发生变化导致单一固定参数滤波器精度降低的问题,提出了一种无人机飞行状态多模型估计算法.在建立单一固定模型紊流风场有色噪声卡尔曼滤波器的基础上,采用多模型自适应卡尔曼估计,得到飞行速度的最优状态估计.仿真结果表明,多模型估计算法在模型参数发生变化时能有效地减小紊流风场对无人机飞行速度的影响,满足飞行速度控制输入的精度要求.     

熵理论在装备保障指挥组织结构优化中的应用

把熵理论应用于装备保障指挥组织结构的优化设计,并以某军区装备部机关组织结构为例,从量化的角度比较改革前后组织结构的时效熵和质量熵,得出结论:改革后的军区装备部机关组织结构有序度优于改革前机关组织结构有序度。     

基于OSG的弹道导弹火力打击三维仿真研究

OpenSceneGraph(开放场景图,OSG)是当前流行的三维仿真引擎,具有开源可控的优点.利用OSG建立弹道导弹火力打击模型可为开展复杂导弹攻防体系仿真提供支撑.为此,提出一种以导弹发射点和打击点经纬坐标以及弹道高点高度为输入参数的弹道计算模型,并对其三维可视化方法中弹道曲线标绘、导弹尾焰与命中毁伤特效等关键技术进行了研究.仿真结果显示,与STK软件的计算结果相比,本模型的弹道计算误差较小,几乎可以忽略不计,同时可视化效果较为细腻逼真.     

Simulation of the plasticizing behavior of composite modified double-base (CMDB) propellant in grooved calendar based on adaptive grid technology

The frequent occurrence of safety accidents during the calendering process is caused by the flammable and explosive properties of composite modified double-base (CMDB) propellant. Optimization of process parameters with the aid of fluid simulation technology could effectively ensure the safety of the calendering process. To improve the accuracy of the simulation results, material parameters and model structure were corrected based on actual conditions, and adaptive grid technology was applied in the local mesh refinement. In addition, the rheological behavior, motion trajectories and heat transfer mechanisms of CMDB propellant slurry were studied with different gaps, rotational rates and temperatures of two rollers. The results indicated that the refined mesh could significantly improve the contour clarity of boundaries and simulate the characteristics of CMDB propellant slurry reflux movement caused by the convergent flow near the outlet. Compared with the gap, the increased rotational rate of roller could promote the reflux movement and intensify the shear flow of slurry inside the flow region by viscous shear dragging. Meanwhile, under the synergistic effect of contact heat transfer as well as convective heat exchange, heat accumulated near the outlet and diffused along the reflux movement, which led to the countercurrent heat dissipation behavior of CMDB propellant slurry. The plasticizing mechanism of slurry and the safety of calendering under different conditions were explored, which provided theoretical guidance and reference data for the optimization of calendering process conditions. Based on the simulation results, the safety of the CMDB propellant calendering process could be significantly improved with a few tests conducted during a short research and development cycle.     

一种通用仿真支撑系统在模拟器研制中的应用

介绍了一种通用仿真支撑系统MINIS的功能及主要特点,阐述了其建模原理与实现方法,并以一个电站模拟器研制的实例说明了其在仿真软件开发中的应用.     

非线性控制在磁悬浮系统中的应用

用滑模变结构控制原理设计磁悬浮系统非线性控制器，并在磁悬浮球装置上进行了试验，结果证实这种控制器具有完全的鲁棒性、良好的参数适应性，设计方法也有广泛的适用性。悬浮系统的刚度有显著的提高。     

基于FrFT的差分跳频通信LFM干扰抑制算法

针对差分跳频通信系统抗LFM干扰能力不足的问题,利用差分跳频信号和LFM干扰信号调频斜率参数的不同,通过估计采样信号中LFM干扰信号的调频斜率K和旋转阶次α参数,结合分段、参数估计和均值处理提高估计精度,进一步在采样信号的分数阶时频域二维参数平面(α,μ)中利用LFM干扰信号频带外的平面均值替代LFM信号成分,实现对差分跳频通信中LFM干扰信号的抑制。仿真结果表明,该算法可有效抑制差分跳频信号中LFM干扰信号,提高信噪比约11 d B。