基于改进模糊综合评判法的告警器能力评估

针对模糊综合评判法在告警器评估时的有效评估问题,对评估过程的指标赋权、隶属度、信息集合算子进行了研究,提出了一种改进的适合告警器的模糊综合评判方法。该方法根据最小二乘原理和离差函数,把目标规划方法应用到组合赋权之中,充分考虑了权重的主客观因素;建立了基于隶属云的评估模型,用隶属云代替隶属函数,保留了隶属度的随机特性;提出了将密度加权平均(Density Weighted Average,DWA)算子用到信息集结中,充分利用了所有的评估信息。通过对某型机载雷达告警器的有效评估,表明了该方法的合理性。     

面向飞参数据处理应用的数据平滑算法对比

对飞参原始记录数据进行预处理是有效利用飞参数据的基础。介绍了三种典型数据平滑算法的原理,建立仿真航线,并以飞参经度和纬度通道数据为例,对三种平滑算法的处理效果进行了对比研究。结果表明,当误差服从正态分布以及广义正态分布时,通过选取适当参数,Vondrak算法相对于滑动平均和加权局部多项式回归算法具有明显优势,从而为飞参原始记录数据的预处理算法选择提供了参考。     

Assessing the value of demand sharing in supply chains

We consider the problem of assessing the value of demand sharing in a multistage supply chain in which the retailer observes stationary autoregressive moving average demand with Gaussian white noise (shocks). Similar to previous research, we assume each supply chain player constructs its best linear forecast of the leadtime demand and uses it to determine the order quantity via a periodic review myopic order‐up‐to policy. We demonstrate how a typical supply chain player can determine the extent of its available information in the presence of demand sharing by studying the properties of the moving average polynomials of adjacent supply chain players. The retailer's demand is driven by the random shocks appearing in the autoregressive moving average representation for its demand. Under the assumptions we will make in this article, to the retailer, knowing the shock information is equivalent to knowing the demand process (assuming that the model parameters are also known). Thus (in the event of sharing) the retailer's demand sequence and shock sequence would contain the same information to the retailer's supplier. We will show that, once we consider the dynamics of demand propagation further up the chain, it may be that a player's demand and shock sequences will contain different levels of information for an upstream player. Hence, we study how a player can determine its available information under demand sharing, and use this information to forecast leadtime demand. We characterize the value of demand sharing for a typical supply chain player. Furthermore, we show conditions under which (i) it is equivalent to no sharing, (ii) it is equivalent to full information shock sharing, and (iii) it is intermediate in value to the two previously described arrangements. Although it follows from existing literature that demand sharing is equivalent to full information shock sharing between a retailer and supplier, we demonstrate and characterize when this result does not generalize to upstream supply chain players. We then show that demand propagates through a supply chain where any player may share nothing, its demand, or its full information shocks (FIS) with an adjacent upstream player as quasi‐ARMA in—quasi‐ARMA out. We also provide a convenient form for the propagation of demand in a supply chain that will lend itself to future research applications. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 515–531, 2014     

非平稳高斯序列最大值的几乎处处中心极限定理

在较弱的条件下,研究了一类非平稳高斯序列的几乎处处中心极限定理.设{Xa,n≥1}为一非平稳高斯序列,记其协方差为rij=Cov(Xi,Xj).假设该序列满足如下条件:对充分大的n,若存在0<α<1当|i-j|>nα时,rijlog|j-i|(l0glog|j-i|)1+ε一致有界.在这一条件下,通过利用概率极限理论,...     

基于OPENGL的面目标平均相对毁伤计算方法

目前,均匀面目标平均相对毁伤的计算无论是解析法还是模拟法都采用了将面目标离散化的思想,存在着离散方法困难、计算精度差等特点.基于OpenGL像素颜色混合机制,提出了直接用像素点对面目标进行离散的方法,并结合Monte-Carlo模拟方法实现了对均匀面目标平均相对毁伤的计算,给出了算法的实现步骤,通过计算实例对计算结果进行了分析.实验结果表明,此方法是计算均匀面目标平均相对毁伤一种快速有效的方法.     

大气对流层气体组分随高度变化的理论预期

利用大气对流层温度随高度变化的规律,采用局部平衡的多分子混合模型,从理论上论证了对流层气体组分随高度变化的规律,发现大气各主要成分体积分数、分子平均摩尔质量均随高度线性变化,并拟合数值计算结果得到了相关参数。氧气的相对体积分数随高度明显下降,而氮气的相对体积分数却明显上升;但是相比于温度随高度的变化,大气分子平均摩尔质量的改变可以忽略。该理论比以往其他模型预测大气压强随高度变化规律具有更自然、更接近实际的优势。     

微波超视距条件下舰船目标RCS分层计算方法

针对微波超视距条件下海面舰船目标的散射特性,提出了一种舰船目标雷达散射截面(RCS)的分层计算方法.首先,研究并给出了随机摆动状态下舰船目标各局部散射体的非相干叠加条件;在此基础上,提出了微波超视距条件下舰船目标RCS的计算流程,针对目标的几何建模、模型划分、遮挡面判定、平均RCS计算等进行了详细阐述;最后,以某型舰船...     

虚拟战场中坦克的快速碰撞检测算法

为了使虚拟战场中的坦克仿真运动有较高的真实性,必须处理坦克与场景中的物体及地形的碰撞问题。提出了碰撞检测的简化包围盒算法及地形匹配算法,分别解决这两种碰撞问题。在地形匹配算法中,依据地形平均曲率划定地形范围,地形平缓的地带采用两点匹配法,变化较为剧烈的地带采用三点匹配法。这两种简化的处理方法降低了系统的计算要求,满足了系统仿真的真实性需求。     

The impact of exponential smoothing forecasts on the bullwhip effect

An important phenomenon often observed in supply chain management, known as the bullwhip effect, implies that demand variability increases as one moves up the supply chain, i.e., as one moves away from customer demand. In this paper we quantify this effect for simple, two‐stage, supply chains consisting of a single retailer and a single manufacturer. We demonstrate that the use of an exponential smoothing forecast by the retailer can cause the bullwhip effect and contrast these results with the increase in variability due to the use of a moving average forecast. We consider two types of demand processes, a correlated demand process and a demand process with a linear trend. We then discuss several important managerial insights that can be drawn from this research. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 269–286, 2000     

分兵集火、凡船皆战——浅析美军“分布式杀伤”概念

通过梳理美军"分布式杀伤"概念的提出背景、提出过程、内涵意义,阐述了"分布式杀伤"的三条制胜之道,即符合海战客观环境、符合科技进步方向、符合战争演变趋势。此外,文章还分析了"分布式杀伤"实际执行过程中的几大难点和缺陷,包括指挥控制问题、舰船能力问题、成本和后勤补给问题、防御有效性问题。