Radar pulse interleaving for multi‐target tracking

In a multifunction radar, the maximum number of targets that can be managed or tracked is an important performance measure. Interleaving algorithms developed to operate radars exploit the dead‐times between the transmitted and the received pulses to allocate new tracking tasks that might involve transmitting or receiving pulses, thus increasing the capacity of the system. The problem of interleaving N targets involves a search among N! possibilities, and suboptimal solutions are usually employed to satisfy the real‐time constraints of the radar system. In this paper, we present new tight 0–1 integer programming models for the radar pulse interleaving problem and develop effective solution methods based on Lagrangian relaxation techniques. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

高比重钨合金的烧结成形与组织性能研究

采用液相烧结成形工艺制备了90W-Ni-Fe合金棒,通过分析烧结态钨合金的组织形貌和力学性能,观察合金的断口组织形貌,研究了烧结工艺对高比重钨合金组织性能的影响,认为减少W-W界面,增加W-W界面的结合强度,是提高烧结态钨合金力学性能的有效途径。     

基于模糊推理的机动目标自适应多模型跟踪算法

针对当前空中来袭目标的主要特点,运用模糊理论和多模型理论探索空中机动目标跟踪问题,并设计了一种模糊自适应多模型(FAMM)目标跟踪算法,该算法采用五个基本模型,以加速度估值作为模糊推理系统的输入,经模糊推理融合得到系统状态和方差的估计值以及下一时刻的滤波模型(最多三个).经Monte Carlo仿真研究,与IMM算法相比较,该算法不仅在目标弱机动或不机动条件下,而且在复杂机动时能更稳定、精确地跟踪目标,较好地满足了海上对空防御作战中跟踪机动目标的需求.     

考虑相位噪声影响的单阵元被动合成阵列算法

考虑到现有单阵元被动合成阵列算法对阵元的运动模型假设过于理想且对相位噪声的适应能力不足,首先,提出一种适用于阵元任意机动方式的单阵元被动合成阵列通用算法,进而通过相位噪声模型分析,给出最大相参时间及有效合成阵元数的选取方法,重建了合成阵列的流形矢量,得到了与相位噪声模型相匹配的改进算法.然后,在相位噪声影响条件下,推导了单阵元被动合成阵列波达方向的理论估计方差下限.仿真分析表明,较未考虑相位噪声影响的算法,改进算法能够有效提高相位噪声影响下的单阵元被动合成阵列测向精度.     

HLA的雷达目标跟踪算法验证系统

构建了一个基于HLA的雷达目标跟踪分布式仿真系统。采用组件设计思想,实现目标跟踪组件和滤波组件,并将这两套组件嵌入到目标跟踪分布式仿真系统中。实践结果表明:基于组件思想构建的目标跟踪和滤波算法能够很好嵌入到分布式雷达目标跟踪系统中,从而为跟踪算法的合理选择、算法参数的优化设计,以及实际系统的研制提供有力支撑。     

高斯马尔可夫融合算法在卡尔曼滤波中的应用

针对目前常用的按标量、对角阵、矩阵加权融合方法过程较复杂,计算负担较重的问题,结合三维目标跟踪模型提出一种高斯马尔可夫融合方法来融合卡尔曼滤波估计值,不需要计算局部稳态滤波误差互协方差,只需要知道传感器的观测噪声方差就可以了。计算方法和操作相对简单,省略了很多繁琐步骤也能达到不错的滤波融合效果,通过仿真证明了此方法的可行性和高效性。     

The Shi Lang,a vehicle for regional change?

In a succession of disclosures over the summer of 2011, the People's Republic of China acknowledged the near completion of its first aircraft carrier and the initiation of a carrier building program. These revelations have come at a time of increased tension in the South China Sea on top of the wider worries in the region concerning China's overly assertive stance and the pace of its military modernization. This perspective will examine why the status of the vessel and the program have now been made public, in addition to surveying the wider implications this upgrade to Chinese maritime capabilities will have on the stability of the region over the coming years. However, this paper concludes that there is, at present, no reason for the sensationalism nor the threat‐mongering seen in many media outlets, of late. Hastily drawn conclusions based primarily on realpolitik fail to understand the nuances of this issue.     

基于任务的连续出动舰载机航空保障重调度研究

对舰载机和各种保障资源进行调度是提高舰载机航空保障效率、保证舰载机所承担作战任务顺利完成的有效手段。为了克服以往研究中没有考虑作战任务变更对舰载机航空保障调度的影响,使用重调度的理论与方法研究了基于任务的连续出动舰载机航空保障重调度问题,建立了连续出动舰载机航空保障重调度模型。采用免疫算法对模型进行求解,可以避免模型的解空间可能出现组合爆炸问题。最后通过一个实例表明该模型可以很好的应对由作战任务变更所引起的重调度问起,算法求解速度满足作战需求,从而验证了模型的准确性及算法的有效性。     

Influence of magnetically constricted arc traverse speed (MCATS) on tensile properties and microstructural characteristics of welded Inconel 718 alloy sheets

The magnetically constricted arc technique was implemented to mitigate the heat input related metal-lurgical problems in Gas Tungsten Arc Welding (GTAW) of Inconel 718 alloy particularly Nb segregation and subsequent laves phase evolution in fusion zone. This paper reports the direct effect of magnetically constricted arc traverse speed (MCATS) on bead profile, tensile properties and microstructural evolution of Inconel 718 alloy sheets joined by Gas Tungsten Constricted Arc Welding (GTCAW) process. The mechanism amenable for the microstructural modification and corresponding influence on the tensile properties of joints is investigated both in qualitative and quantitative manner related to the mechanics of arc constriction and pulsing. It is correlated to the solidification conditions during welding. The relationship between MCATS and Arc Constriction Current (ACC) was derived. Its interaction effect on the magnetic arc constriction and joint performance was analysed. Results showed that the joints fabricated using CATS of 70 mm/min exhibited superior tensile properties (98.39% of base metal strength with 31.50% elongation). It is attributed to the grain refinement in fusion zone microstructure leading to the evolution of finer, discrete laves phase in interdendritic areas.     

一种适于DSPs实现的BPSK载波同步方法

提出了全数字接收机中一种软件实现的BPSK载波同步方法 ,并给出了性能分析 ,适合于在存储空间和实时性都有要求的背景下的应用。该方法充分利用软件实现的优势 ,克服了传统方法的一些弱点 ,适合于在数字信号处理器 (DSPs)上实现