NON‐LINEARITY IN THE DEFENCE EXPENDITURE – ECONOMIC GROWTH RELATIONSHIP IN TAIWAN

As we enter the 21st Century, technologies originally developed for defense purposes such as computers and satellite communications appear to have become a driving force behind economic growth in the United States. Paradoxically, almost all previous econometric models suggest that the largely defense‐oriented federal industrial R&;D funding that helped create these technologies had no discernible effect on U.S. industrial productivity growth. This paper addresses this paradox by stressing that defense procurement as well as federal R&;D expenditures were targeted to a few narrowly defined manufacturing sub‐sectors that produced high tech weaponry. Analysis employing data from the NBER Manufacturing Productivity Database and the BEA’ s Input Output tables then demonstrates that defense procurement policies did have significant effects on the productivity performance of disaggregated manufacturing industries because of a process of procurement‐driven technological change.     

A stochastic air combat logistics decision model for Blue versus Red opposition

Technologically advanced aircraft rely on robust and responsive logistics systems to ensure a high state of operational readiness. This paper fills a critical gap in the literature for combat models by closely relating effectiveness of the logistics system to determinants of success in combat. We present a stochastic diffusion model of an aerial battle between Blue and Red forces. The number of aircraft of Blue forces aloft and ready to be aloft on combat missions is limited by the maximum number of assigned aircraft, the reliability of aircraft subsystems, and the logistic system's ability to repair and replenish those subsystems. Our parsimonious model can illustrate important trade‐offs between logistics decision variables and operational success.     

近地卫星Ka频段数传链路抗雨衰ACM模式设计

针对近地卫星数传时的信道时变性和严重的Ka频段雨衰现象,采用自适应编码调制（ACM）技术能够充分利用链路资源,相对于传统的固定编码调制方式,进一步提高了链路的数据吞吐量。提出了近地卫星Ka频段数传链路ACM模式设计方法,在降雨环境下建立Ka频段数传链路模型,根据信道状况确定ACM选用模式;采用基于导频符号的最大似然信噪比估计算法结合移动平均的平滑方法实现信道估计,有效地减小了估计值的波动。仿真结果表明,无论晴天还是雨天,采用提出的卫星数传链路ACM模式设计方法,能够在保证系统可靠性的同时获取较高的数据吞吐量。     

Recursive weighted least squares estimation algorithm based on minimum model error principle

Kalman filter is commonly used in data filtering and parameters estimation of nonlinear system,such as projectile's trajectory estimation and control.While there is a drawback that the prior error covariance matrix and filter parameters are difficult to be determined,which may result in filtering divergence.As to the problem that the accuracy of state estimation for nonlinear ballistic model strongly depends on its mathematical model,we improve the weighted least squares method(WLSM)with minimum model error principle.Invariant embedding method is adopted to solve the cost function including the model error.With the knowledge of measurement data and measurement error covariance matrix,we use gradient descent algorithm to determine the weighting matrix of model error.The uncertainty and linearization error of model are recursively estimated by the proposed method,thus achieving an online filtering estimation of the observations.Simulation results indicate that the proposed recursive esti-mation algorithm is insensitive to initial conditions and of good robustness.     

Terror and Internal Migration in Israel

This paper empirically analyses the effect of terror on internal migration between Israeli subdistricts. Using a unique data-set comprising migration flows for the period 1999–2012 and the number of rocket and non-rocket attacks, we test the hypotheses that terror reduces migration into an affected subdistrict and increases migration out of it. According to our results, the effect of terror on migration is asymmetric as we only find evidence for the first hypothesis. This result remains when we use an instrumental variables strategy that corrects for underreporting of the number of rocket attacks. The largest effects of rocket attacks are found for migration into the Southern subdistrict of Ashqelon as well as into other border regions in Northern Israel, while non-rocket attacks also have substantial effects in the more populous centres of Jerusalem and Tel Aviv.     

基于LMS2UKF的主/被动雷达融合算法

在主/被动雷达双传感器目标跟踪背景下,针对IMM算法的计算量大,提出一种基于变结构多模型思想的LMS2UKF分布式融合算法。该算法将LMS算法和UKF滤波算法结合进行矩阵加权融合。与IMM2UKF算法进行仿真比较,结果表明在相同情况下,本算法有较好的稳定性和较好的定位精度。     

外加电位条件下7A52铝合金应力腐蚀开裂敏感性研究

摘要：采用电化学极化手段和慢应变速率拉伸试验,结合扫描电镜观察合金断口形貌,研究了外加电位对7A52铝合金应力腐蚀开裂敏感性的影响。研究结果表明：合金在3．5％NaCl溶液中的应力腐蚀开裂敏感性与外加电位有强烈的相关性,开裂敏感性在外加电位为一0．95V时最低,外加电位起到阴极保护的作用;在外加电位为一1V时有所升高,但仍然低于开路电位条件下的敏感性;在一1．1V时最高,应力腐蚀过程以氢脆为主;在一1．2V时又有所降低,阴极析出的氢以气态逸出而降低应力腐蚀开裂敏感性。     

TIN数字地形模型的通视性算法

数字地形模型的地形通视性分析有着广泛的应用,对TIN地形模型上两点间的通视性算法进行了研究、改进与实现.研究结果表明,视线与三角形相交法算法简单直观,但计算效率太低;改进的视线与边相交法数据结构简单,编程实现容易,适合地形数据结构单一的系统;而投影覆盖检测算法通用性好,适合地形数据结构多样的系统.     

城市居民区地震火灾发生率的推估方法

分析了地震火灾产生的原因及其影响因素,提出了一个城市地震火灾危险性分析的模型,利用民事火灾的统计分析结果,给出了城市地震火灾发生率的公式,在此基础上探讨了地震火灾危险性分析方法,给出了分析实例。     

质量块控制自旋导弹的Lyapunov稳定性分析

给出了质量矩控制导弹的动力学模型及在一定条件下的简化动力学模型;用Lyapunov分析方法给出了动稳定性条件。结果说明,推力和静稳定度越大,越有利于动态稳定;阻力越大越不利于动态稳定。