多准则下反导作战单、多遭遇点预测模型

整个反导射击过程可以简单看作一个基于预测的遭遇点起始的,不断重复、修正的过程。分析遭遇点预测的时间和空间前提,并给出遭遇点预测的3个基本准则;在多准则下建立了单遭遇点预测模型,给出了模型公式中未知量的转化方法;分射击-观察-射击和射击-射击两种情况建立了多准则下多遭遇点预测和优化模型,并给出了拦截弹最晚发射时间的计算方法;就观察时机对遭遇点预测的影响进行了分析与建模。部分研究属于探索性的研究,相关结论对指控模型开发和实施连续反导,从方法和作战理念方面提供了一些参考。     

任意分布随机数的FPGA实现

为了满足数字电路板的随机测试需求,在Simulink/DSP Builder中建立了产生任意分布随机数的模型,并在FPGA上进行了半实物仿真和性能分析,结果表明该模型达到了设计要求,具有实用价值。     

基于FPGA的数字类板件比对测试平台设计

数字类板件的检测包括功能检测和时序检测,由于该类板件输入输出信号路数多、时序复杂,一直是电子系统中测试的难点。给出了一种基于FPGA的测试平台,可在不依赖于计算机的情况下,自动给出被测板件与原板件的逻辑功能和时序关系的比对测试结果,且时序误差可手动设置,并能确定不一致输出的位置和此时输入的测试矢量。该平台已用于某引进装备中数字类板件的比对测试,更换不同测试头也可用于其他板件的测试。     

Timing of information acquisition in a competitive environment

This article investigates the impact of timing on sellers' information acquisition strategies in a duopoly setting. Market uncertainty is captured by a representative consumer who has a private taste for the product's horizontal attribute, and both sellers can acquire this information either before (ex‐ante acquisition) or after (ex‐post acquisition) observing their own product qualities. We identify several conflicting effects of information acquisition that vary significantly in its timing and market characteristics. In the monopoly scenario, information acquisition is unambiguously beneficial and ex‐ante acquisition is the dominant option, because it helps a seller not only design the proper product but also craft better pricing strategy. By contrast, when there is competition, information acquisition eliminates the buffer role of market uncertainty and leads to the fiercest production or pricing competition, which makes the subsequent effects of acquisition detrimental, and a seller's payoff is nonmonotonic in terms of its acquisition cost. Moreover, compared with the ex‐ante information acquisition, ex‐post information acquisition normally generates higher sellers' equilibrium payoffs by postponing the timing of acquisition and maintaining product differentiation. Nonetheless, ex‐post information acquisition also provides the seller with greater acquisition incentive and occasionally makes him worse off than that in the ex‐ante scenario. Thus, in a competitive environment, having the option of information acquisition and flexibility in its timing can be both detrimental and irresistible. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 3–22, 2016     

Nonlinear pricing with consumer satiation

In various scenarios, consumers may become satiated with products, and the degree of satiation is directly associated with their prior experiences. Confronted with consumer satiation, the seller is unable to either identify consumers who have a higher likelihood of being satiated ex ante or distinguish satiated from non‐satiated consumers ex post. Therefore, the seller should address dynamic selling, valuation uncertainty, and quantity decisions, all of which are important operational issues. We consider a two‐period problem in which consumer types are influenced by their prior consumption experiences. Faced with these consumers, the seller intends to optimize quantities and adjust the prices of the products in each period to maximize revenue. We find that the seller may reduce ex ante production quantity as some consumers become satiated. Moreover, the ex ante quantity is first decreasing and then increasing with regard to the satiation rate. Furthermore, two‐period information asymmetries may provide a rationale for upward distortion in quantity when consumer preferences are highly sensitive to first‐period consumption. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 386–400, 2016     

一种有效的距离连接选择度估计方法

距离连接在空间数据库中有着广泛的应用,而距离连接的选择度估计是优化距离查询的基础。通过综合分析和比较了现有的选择度估计技术,提出了一种利用米诃夫斯基和与直方图进行距离连接选择度估计的新方法。实验结果证明该种方法能够有效地进行距离连接选择度估计。     

轴对称静电场不等距多重网格法的研究

研究了不等距多重网格法,可用于区域形状任意和有内电极的实际电子光学系统轴对称电场的计算,特别是对于求解区域大、部分区域电场精度要求高的场合,较好地解决了计算精度与划分网格点数之间的矛盾,可广泛应用于分析设计静电聚焦像管的电子光学系统,以及摄像管电子枪的发射系统等.     

虚拟心脏介入手术系统的血流模拟

虚拟心脏介入手术系统的血流效果模拟是系统中模型模拟的关键。实时而准确的血液流动效果增强了虚拟手术系统的真实感。在分析心血管内的血液流动物理模型的基础上,结合弹性腔模型,采用了改进的粒子系统方法,建立和实现了新的虚拟心脏介入手术系统的血流模型,满足了心脏介入系统的实时性和真实感要求。     

Supplier certification and quality investment in supply chains

Global sourcing has made quality management a more challenging task, and supplier certification has emerged as a solution to overcome suppliers' informational advantage about their product quality. This article analyzes the impact of certification standards on the supplier's investment in quality, when a buyer outsources the production process. Based on our results, deterministic certification may lead to under‐investment in quality improvement technology for efficient suppliers, thereby leading to potential supply chain inefficiency. The introduction of noisy certification may alleviate this under‐investment problem, when the cost of information asymmetry is high. While allowing noisy certification always empowers the buyer to offer a menu to screen among heterogeneous suppliers, the buyer may optimally choose only a limited number of certification standards. Our analysis provides a clear‐cut prediction of the types of certifiers the buyer should use for heterogeneous suppliers, and we identify the conditions under which the supplier benefits from noisy certification. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

Introduction: Symposium on defence economics

This study revisits the relationship between defence spending and economic growth via a Keynesian model in Pakistan using the autoregressive distributive lag bounds testing approach to cointegration. Empirical evidence suggests a stable cointegration relationship between defence spending and economic growth. An increase in defence spending reduces the pace of economic growth confirming the validity of Keynesian hypothesis in this case. Current economic growth is positively linked with economic growth of previous periods while a rise in non-military expenditures boosts economic growth. Interest rate is inversely associated with economic growth. Finally, unidirectional causality running from military spending to economic growth is found.