多目标跟踪中数据互连的有效算法

该有效算法是为计算联合概率数据互连滤波器(JPDAF)中量测原点的后验概率而开发的。这种算法的遗传平行性使其适应于在多处理机系统中实现。用这种算法把JPDAF中每个量测原点的后验概率分解成两部分。第一部分的计算很普通,而第二部分的计算用本文开发的算法并证明与稳定度有关。分析在一般情况和最坏情况下该算法的计算复杂性。算法分析可使我们得出该算法在一般情况下比其他现有算法更有效。     

全欧数字式移动无线电系统的六种中比特速率编码器的评估

自1982年以来,在欧洲邮政与电信管理联合会(CEPT)的移动通信专家组(GSM)协调下,一种数字式蜂窝状移动无线电系统在欧洲已经在研制之中。在最近的一次协调实验中,已完成了对此系统的六种待选的16kbit/s 语声编码方案输出的试听评价测试。实验包含一个规则脉冲激励编码器,一个多脉冲激励编码器,和四个子带编码器。由 CSELT(意大利)主持了一次实验性会议,在七个不同的实验室里完成其主观测试。为了比较的目的,实验中包含了对正在使用的一种蜂窝式压扩 FM 系统的测试。这六种编译码器 Codec 在主观质量,传输延迟,和实现的难易程度方面进行了比较。在这方面的对比中,没有哪个 Codec 在各方面都好。总之,规则脉冲激励的线性编测预码器(RPE-LPC)能提供最好的语声质量,它有允许的复杂性和延迟,因而被选出供进一步改进。最后,这种 Codec 的一种改进形式,即带有长期预测的规则脉冲激励 LPC(RPE—LPC)编码器被选用于欧洲数字移动系统。     

三封来信促整改 凝心聚力结硕果

正六月的树,葱葱郁郁,闪着绿色的光芒;六月的花,生机勃勃,浸润盛夏的希望;六月的风,柔和温馨,吹来沃野的清香;六月的雨,缠绵多情,挥洒丰收的印象。6月9日,记者迎着一阵阵扑面而来的热浪,来到距离博乐市以东40公里的五师八十一团。树木茂盛,鲜花盛开,芳草碧绿,俨然一帧花红叶茂的水墨长卷绵延于六月的天地之间。在八十一团广场的树荫下,职工李翠兰等人正在休息乘凉,当记者上前问及"三封信"时,他们皆点头示意了解此事。     

海战场态势评估问题的研究

对海战场综合态势进行态势评估和威胁分析是信息融合系统的最高层级,态势评估结果将对指挥员的指挥决策起到非常重要的作用。根据海军作战理论分析了海战场态势的表示方法,并基于模板方法设计了一种战场当前态势与模板数据库中态势进行匹配的算法。该算法特别适用于高层推理如态势或威胁评估。     

Experimental and numerical investigations of interface properties of Ti6Al4V/CP-Ti/Copper composite plate prepared by explosive welding

Explosive welding technique is widely used in many industries. This technique is useful to weld different kinds of metal alloys that are not easily welded by any other welding methods. Interlayer plays an important role to improve the welding quality and control energy loss during the collision process. In this paper, the Ti6Al4V plate was welded with a copper plate in the presence of a commercially pure titanium interlayer. Microstructure details of welded composite plate were observed through optical and scanning electron microscope. Interlayer-base plate interface morphology showed a wavy structure with solid melted regions inside the vortices. Moreover, the energy dispersive spectroscopy analysis in the interlayer-base interface reveals that there are some identified regions of different kinds of chemical equilibrium phases of Cu–Ti, i.e. CuTi, Cu₂Ti, CuTi₂, Cu₄Ti, etc. To study the mechanical properties of composite plates, mechanical tests were conducted, including the tensile test, bending test, shear test and Vickers hardness test. Numerical simulation of explosive welding process was performed with coupled Smooth Particle Hydrodynamic method, Euler and Arbitrary Lagrangian-Eulerian method. The multi-physics process of explosive welding, including detonation, jetting and interface morphology, was observed with simulation. Moreover, simulated plastic strain, temperature and pressure profiles were analysed to understand the welding conditions. Simulated results show that the interlayer base plate interface was created due to the high plastic deformation and localized melting of the parent plates. At the collision point, both alloys behave like fluids, resulting in the formation of a wavy morphology with vortices, which is in good agreement with the experimental results.     

Damage to aircraft composite structures caused by directed energy system: A literature review

This paper presents a comprehensive review of the research studies on direct energy system effect on aircraft composite structures to develop a good understanding of state-of-the-art research and devel-opment in this area. The review begins with the application of composite materials in the aircraft structures and highlights their particular areas of application and limitations. An overview of directed energy system is given. Some of the commonly used systems in this category are discussed and the working principles of laser energy systems are described. The experimental and numerical studies re-ported regarding the aircraft composite structures subject to the effect of directed energy systems, especially the laser systems are reviewed in detail. In particularly, the general effects of laser systems and the relevant damage mechanisms against the composite structures are reported. The review draws attention to the recent research and findings in this field and is expected to guide engineers/researchers in future theoretical, numerical, and experimental studies.     

电子战研究注重海军虚拟现实技术

美国海军研究实验室正在开展利用虚拟现实技术实现电子战仿真的研究,本文对这一称为“海军电子战系统效能分析(ENEWS)”的项目进行了综合介绍,阐述了它的研制目的、系统功能、技术实现原理与工具、系统构成、软件和人机接口设计,并对该项目的开发现状和发展前景作了评述和展望。     

动摇不定的亿万美元舰艇——美国海军SSN-21“海狼“计划

一年前华盛顿防务权威们就已经开始为SSN-21——美国海军建议的21世纪“超级潜艇”——敲起丧钟。原高级众议院武装部队委员会（HASC）助理托尼·巴蒂斯塔要求海军放弃SSN-21计划,回到绘图桌前重新设计更好的舰艇。国会也基本同意巴蒂斯塔和其他评论家的意见。     

未来十年的防御技术

防御系统发展的新趋势是建立战场环境的一种新的处理模式:今后使用能探测和处理一系列所得信号的高集成系统,可对敌人的威胁作出更快、更准确的反应。 新材料和材料处理技术是这类设想的系统的基础。到目前为止仍被看作是相互竞争的技术将被组合在同一设备子系统里。例如,在一衬底上集成硅和砷化镓（GaAs）,将光学和电子信号处理综合在一片组件里。有一种设想是组成一种小型的、高性能多处理机来执行重要