武器握把舒适度量化研究

以手枪的握持舒适度试验为依据，分析影响握把舒适度的因素，提取舒适度量化特征点，并在试验结果的基础上，给出舒适度量化特征值。     

The one‐warehouse multiretailer problem with an order‐up‐to level inventory policy

We consider a two‐level system in which a warehouse manages the inventories of multiple retailers. Each retailer employs an order‐up‐to level inventory policy over T periods and faces an external demand which is dynamic and known. A retailer's inventory should be raised to its maximum limit when replenished. The problem is to jointly decide on replenishment times and quantities of warehouse and retailers so as to minimize the total costs in the system. Unlike the case in the single level lot‐sizing problem, we cannot assume that the initial inventory will be zero without loss of generality. We propose a strong mixed integer program formulation for the problem with zero and nonzero initial inventories at the warehouse. The strong formulation for the zero initial inventory case has only T binary variables and represents the convex hull of the feasible region of the problem when there is only one retailer. Computational results with a state‐of‐the art solver reveal that our formulations are very effective in solving large‐size instances to optimality. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

对流层散射双向时间比对中对流层斜延迟估计

为精确估计对流层散射双向时间比对系统中对流层斜延迟,分析了估计卫星信号对流层斜延迟的Hopfield天顶延迟模型及CFA2.2映射函数模型并对其进行修正,从而适用于对流层散射斜延迟的精确估计。根据北纬35°~37°范围内的三个测站2010—2012三年的气象数据,验证Hopfield模型精度范围小于35 mm,并将三个测站按相互之间基线距离的不同分为三组比对站,利用2012年的气象数据,计算在不同入射角下一年的对流层散射斜延迟,并得出最大斜延迟对应的年积日和入射角。结果表明,三组比对站的最大单向散射斜延迟为21.82~35.45 m。在双向比对抵消90%的情况下,时间延迟为7.3 ns~11.7 ns;相互抵消95%时,时间延迟为3.6 ns~5.9 ns。     

An optimal critical level policy for inventory systems with two demand classes

Traditional inventory systems treat all demands of a given item equally. This approach is optimal if the penalty costs of all customers are the same, but it is not optimal if the penalty costs are different for different customer classes. Then, demands of customers with high penalty costs must be filled before demands of customers with low penalty costs. A commonly used inventory policy for dealing with demands with different penalty costs is the critical level inventory policy. Under this policy demands with low penalty costs are filled as long as inventory is above a certain critical level. If the inventory reaches the critical level, only demands with high penalty costs are filled and demands with low penalty costs are backordered. In this article, we consider a critical level policy for a periodic review inventory system with two demand classes. Because traditional approaches cannot be used to find the optimal parameters of the policy, we use a multidimensional Markov chain to model the inventory system. We use a sample path approach to prove several properties of this inventory system. Although the cost function is not convex, we can build on these properties to develop an optimization approach that finds the optimal solution. We also present some numerical results. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

Why internal conflict deteriorates state capacity? Evidence from Colombian municipalities

Previous work has documented a negative correlation between internal conflict and state capacity. We attempt to shed light on mechanisms that underlie this relationship, using data for Colombian municipalities. We rely on identifying heterogeneous effects of different types of violent events on state capacity, taking advantage of variability across municipalities in the prevalence of specific manifestations of conflict and their intensity. Our findings suggest that events making civilians feel targeted affect the state’s capacity to collect taxes, while those reflecting a stronger military capacity of illegal armies, in particular their large-scale attacks, affect the state’s capacity to provide public goods.     

带有可信度因子的直觉模糊近似推理方法

针对基于相似度的直觉模糊近似推理问题,提出一种基于加权相似度量的直觉模糊推理方法。首先定义一种新的直觉模糊相似度度量公式,加入权重参数解决各维特征分配不均匀的问题,弥补了现有直觉模糊相似度量的缺陷。然后构建基于直觉模糊产生式规则的直觉模糊近似推理模型,加入可信度因子解决了随机性引起的信息不确定问题,同时给出模型的推理算法和计算步骤。最后通过实例验证了该方法的实用性和有效性,其在意图识别、目标识别等信息融合领域有良好的应用前景。     

指挥信息系统需求体系框架

需求工程是指挥信息系统整个开发周期中的第一步,正确且全面地确认系统的需求是成功开发指控系统的关键.指挥信息系统需求体系框架是从需求开发的内容上规范需求工程技术在指挥信息系统需求开发中的应用.从需求的本义出发,在分析总结IEEE、INCOSE以及OMG等研究机构关于需求内涵与分类的研究基础上,本着与C4ISR/DOD AF一致的原则,结合近年我军指挥信息系统需求开发的实践经验,提出了指挥信息系统需求体系框架.     

用卷积神经网络分类最大稳定极值区域实现汉字区域定位

获取对应笔画级连通区的最大稳定极值区域,实施形态学闭操作融合相距较近的最大稳定极值区域,融合后最大稳定极值区域对应的单个汉字区域;利用灰度共生矩阵描述最大稳定极值矩形区域的纹理信息,将其作为卷积神经网络的输入,卷积神经网络对最大稳定极值区域进行分类,过滤非汉字部分;利用最大稳定极值区域颜色直方图的Bhattacharyya距离等特征对最大稳定极值区域进行聚类,同一类最大稳定极值区域组合得到汉字文本候选区域;再次利用卷积神经网络对候选文本区域进行分类,过滤非文本部分,剩余的就是定位到的汉字文本区域。实验结果表明,该算法对于汉字区域定位具有良好的效果。     

基于MATLAB的TDMA/CSMA混合协议仿真分析

TDMA(时分多址)和CSMA(载波侦听)是两种常见的Ad Hoc网络多址接入方式,两种方法各有利弊。TDMA避免了节点之间的冲突,但是平均时延随着网络规模的扩大而急剧增长,当某节点在给定的时隙内没有发送请求时,会产生空时隙,造成资源浪费;CSMA采用竞争的方式,当网络规模扩大时,节点的碰撞概率很大,信道利用率降低。根据两者的特点,提出了TDMA/CSMA混合多址接入协议,采用固定分配和动态分配相结合的方式,进一步提高网络吞吐量、降低平均时延,并通过MATLAB软件对协议进行仿真建模,验证其性能。     

基于TRL的技术成熟度模型及评估研究

研究以色列区域导弹防御系统的发展动因、进展、影响与趋势,重点分析了以色列近程、中程、远程导弹防御系统的技术和能力,探讨了以色列区域导弹防御系统的影响及发展趋势。