基于交会角的多站交叉定位融合算法及误差仿真

交叉定位是一种利用多站角度信息进行解算获得目标距离信息的方法,利用双站即可完成对目标的三维定位,但此时的误差分布特性和定位精度较差。在多站系统中,可以利用目标的冗余信息进行数据融合,以改善雷达交叉定位系统中交叉定位误差分布特性和定位精度,提出了基于交会角的多站交叉定位融合算法,仿真结果给出了融合前后的定位误差分布图。与以往的方法相比,此方法计算量小,实时性较好。     

基于几何位置的JTIDS定位误差建模与分析

JTIDS中信息源与用户的相对几何位置对定位精度有较大影响,为了获得定位误差随几何位置的变化规律,从JTIDS的多点时差测距交叉定位方法出发,采用误差传递理论,研究了用户与定位源几何位置与定位误差的关系,推导出基于几何位置的JTIDS定位误差模型,并以该模型为依据分析了定位误差的变化规律,最后用误差椭圆的形式将结论进行了直观描述。仿真结果表明:所建立的模型能较好反映定位误差分布特性,所得结论为JTIDS端机工作时选择定位源提供了参考。     

无源雷达的二维定位精度分析和图形描述

为了分析无源雷达三站时差定位技术的定位精度,综合考虑了目标水平面位置和高度以及测量站站址对定位精度的影响,在三维空间直角坐标系下建立定位精度模型,通过计算机仿真分别采用相对定位误差和椭圆概率误差表示法描述定位误差分布.仿真结果表明,所建模型正确、有效,两种表示法能从不同角度描述定位误差的空间分布,两者反映出的分布信息可...     

双基阵声纳系统水下目标被动定位精度分析

研究了基于双基阵的被动定位方法,论述了仅利用方位测量信息的纯方位定位原理,推导出了定位误差的几何分布关系式及定位精度达到最高的测向线交会角大小,分析了测向误差及站址误差对定位精度的影响,对定位误差与基线、目标方位的关系作了较细致的分析,同时给出了整个探测区域的GDOP分布图,得出了满足一定定位精度要求的交会角范围.该问...     

基于改进QPSO-NN的冗余机械臂逆运动学算法

针对某种冗余机械臂逆运动学求解的问题,提出了一种基于改进量子粒子群神经网络的求解算法。以冗余机械臂末端位姿为输入,经神经网络求得其逆解;针对神经网络输出结果误差较大的问题,把神经网络求初值加入初始化的粒子群中,通过基于Metropolis准则改进量子粒子群算法,避免了量子粒子群算法的早熟现象;以关节坐标经正向运动学求得的末端位姿和期望位姿的误差为适应度函数,对机械臂关节坐标迭代寻优。仿真结果表明该方法结合了神经网络算法的快速性和改进量子粒子群算法的精确性,满足求冗余机械臂逆运动学问题的速度和精度要求。     

运动矢径对AUV协同定位精度影响的仿真

针对在基于运动矢径的自主水下航行器(AUV)协同定位算法中运动矢径对定位精度的影响进行了仿真分析.利用扩展卡尔曼滤波设计了AUV协同定位算法,通过设定不同的运动矢径对该协同定位算法进行仿真,分析研究了运动矢径的变化对定位精度的影响.仿真结果表明,该定位算法受运动矢径的影响,增大运动矢径会使滤波误差波动变大,降低定位精度.     

误差配准在两种纯距离定位算法的应用比较

组网雷达系统中,由于观测信息量的增加,对目标存在多种定位算法。很多情形下,误差配准公式是基于某一定位算法推导而来,误差配准的结果也相应的用来提高此定位算法的定位精度。定位算法的复杂程度不同导致基于此算法推导误差配准公式难度不一致,不同定位算法的定位精度也不尽相同。因此,对两种多距离定位算法的定位精度、误差配准推导难易程度进行了理论分析和仿真计算,给出了定位精度的解析表达式和仿真结果。利用表达式简单的定位算法推导基于最小二乘的误差配准公式,并将误差配准结果反馈给定位精度高的定位算法,以最大程度提高误差配准结果的应用效果,减轻计算复杂度,提高信息的利用度。     

基于线性数据融合的双椭圆定位模型优化算法

为了充分利用分离式台声源声纳定位系统的冗余测量信息,提高系统的定位精度,提出了基于线性数据融合的双椭圆定位模型优化算法。并通过数值仿真,对不同条件下的定位误差几何分布曲线图(GDOP)进行了研究。仿真结果表明,大部分探测范围内,两个声源之间距离的变化和时间测量误差对定位性能影响较小,而角度测量误差对该算法的定位精度影响较大。与仅利用距离信息进行定位的方法相比较,采用数据融合的优化手段,可以充分利用定位系统的冗余信息,有效地降低了系统的定位误差,探测盲区的定位性能也得到明显改善。仿真结果和性能分析为解决远距离探潜定位优化问题提供了理论依据。     

空间多距离定位极值问题分析

针对空间多站无源定位极值问题,以时差定位原理为研究对象,重点对多距离定位极值进行算法推导,深入分析多站定位的最优精度问题;并以定位极值理论为依据,结合较为全面的仿真案例验证,分析不同误差影响因素下时差定位精度的分布规律;研究表明,多站布站方式是影响空间定位的重要因素之一,为实际工程应用的多站定位算法设计和优化提供了技术支持.     

基于灰狼算法的机器人多关节综合运动轨迹优化

针对机械臂运动需满足高效率和低冲击的问题,在分析机械臂轨迹规划流程的基础上,选取了机械臂末端运动轨迹的六个关键路径点,并基于灰狼算法以时间、平滑度为目标对机械臂运动轨迹进行了优化,获得pareto最优解集。对六自由度机器人的仿真结果表明:将灰狼算法与机械臂的轨迹优化结合能得到比较好的仿真结果,理论上实现了在运动过程中抑制振动,为解决该问题提供了新的方法。     

Helping hands: civil–military cooperation and Italy's military operation abroad

In the Post-Bipolar Era the growing complexity of the military operations requires a new approach for the resolution of international crises. Since the end of the Cold War, peace support operations (PSO) have become the mainstay and principal occupation of most Western armies. At the same time, Italy has been one of the most important actors in such an area. The article focuses on the cooperation between military and civil components (a process called CIMIC) as a key variable in the Italian PSOs. We will analyse in detail the main lessons learned from past military interventions as well as the general context in which new tendencies are taking place. The maintaining of a minimum security frame becomes essential to fulfil activities ‘collateral’ to the mission: reconstructing services and infrastructure, food distribution, water and medication, law and order, de-mining, training of local forces, and supporting local institutions. These are the main tasks to obtain thrust and support from the population.     

Terrorism,insurgency, kidnapping,and security in Africa's energy sector

Energy continues to serve as the bedrock of modern economies and the main driver of modern society. For Africa, the production and supply of energy resources such as crude oil, natural gas, uranium, coal, biomass, biofuels and other renewables are an important source of employment, rents, taxes, royalties and profits. This sector brings in several tens of billions of dollars of revenue annually. The production and delivery of such resources, however, depend on critical infrastructures such as pipelines, refineries, processing plants, terminals, rigs, electrical energy pylons, substations, pump stations, vessels, and tankers. These infrastructures have been attacked by terrorists, insurgents, vandals and saboteurs, all of whom see them as targets against which to register their grievances and extract concessions from the state. This paper is a chronological account of some of the documented incidents of terrorism, insurgency, kidnapping, destruction, sabotage, and human casualties suffered in the oil and gas sectors in Africa between 1999 and 2012. It is based on data extracted from the databases of the RAND Database of World Terrorism Incidents and the University of Maryland's Global Terrorism Database (GTD).     

The UK,interrogation and Iraq, 2003–2008

The UK’s interrogation operations during the conflict in Iraq (2003–2008) are often portrayed by the media as involving significant amounts of mistreatment. This article demonstrates that these practices are not necessarily representative of the UK’s interrogation operations across this conflict. In doing so it contributes to the limited literature on the practice of interrogation and on the UK’s combat operations in Iraq. The UK’s interrogation capability, and therefore its intelligence-gathering capability, is shown to have rested primarily with the military’s Joint Forward Interrogation Team (JFIT). The JFIT suffered from limitations to the number, training and experience of its interrogators and interpreters. It is argued that maintaining a permanent, higher level of preparedness for interrogation by the British armed forces is desirable.     

Remembering and forgetting Mirambo: Histories of war in modern Africa

ABSTRACT

While the study of organised violence is considered essential to understanding the history of the West, and accordingly imbued with various layers of meaning and remembrance, war is widely regarded as inimical to the modern nation in Africa and stable development more broadly. Using examples drawn from primarily from East Africa, this paper considers the ways in which warfare in the deeper (‘precolonial’) past has been framed and envisioned in recent decades, in particular by governments whose own roots lie in revolutionary armed struggle and who began life as guerrilla movements. While in some cases particular elements of the deeper past were indeed mobilised in pursuit of contemporary political goals, in many other scenarios histories of precolonial violence were beheld as problematic and unworthy of remembrance. This paper highlights the paradox and ambiguity which has attended the memory of key aspects of Africa’s deeper past.     

A1 Qaeda and the radical Islamic challenge to western strategy

The September 11 global crisis prompted by the attacks on the World Trade Center and the Pentagon raises major questions concerning the nature and trajectory of terrorism in the post-Cold War global order. Hitherto, terrorism has been largely debated by analysts at the level of nation states. Terrorist and insurgent movements have also been largely anchored in nationalist and ethnic power bases even when they have sought to mobilise a transnational ideological appeal on religious or class grounds. There have been a few exceptions to this pattern such as the alliance between the German Baader-Meinhof group and the Japanese Red Army Faction, but even such international alliances as this did not, until at least the 1980s, presage anything like a global terrorist network necessitating a global strategic response. This study examines terrorism and global strategic responses.     

Tacit support for terrorism: The rapprochement between the USSR and Palestinian guerrilla organizations following the 1967 war

This article demonstrates the inconsistent and wavering Soviet attitude towards national liberation movements in general and the Palestinian organizations in particular. Until the late 1960s, the Soviets viewed these organizations with suspicion, hesitating to engage in political dialogue with them. However, in the 1970s, political and military events in the region, as well as modifications in the Kremlin's Cold War strategies, led to a general shift towards the Middle East in Soviet foreign policy. Soviet leaders showed increased willingness to provide certain Palestinian organizations with arms with which to conduct terrorist activities against Israeli, pro-Israeli, Jewish and Western targets. The article explores the complex relations between Palestinian organizations and the USSR in the field of international terror. The study also exposes and analyzes the nature and content of Soviet–Palestinian arms dialogues and transactions. It provides clear evidence that Soviet policymakers and other luminaries were fully informed of, and sometimes directly involved in, these transactions and dialogues at the highest levels.     

SIM—LISP:一个通信网络管理专家系统外壳的设计与实现

本文介绍了笔者为开发名为OONMES的网络管理专家系统所实现的一个简单专家系统工具SIM-LISP。SIM-LISP是一个用C/C++语言来实现的模拟LISP语言的可调用函数集,它短小精巧,速度快,可以完成针对网管专家系统的事实或规则知识的表示、匹配、合一和推理等基本操作,并有与知识对象的连接功能,是网管专家系统内核实现的支撑环境。     

Helping hands: external support for the KNU insurgency in Burma

This article analyses to what extent the Burmese KNU insurgency made use of external support from states, refugees, and diasporas. Based on extensive fieldwork it is concluded that support from neighbouring states and refugees has for years kept the Karen rebellion alive. Western countries perceived forms of resistance to the illegitimate Burmese regime as just and have therefore played a crucial role in the continuation of conflict in Karen State. It is important that policymakers and donors as well as executing organizations continue to reflect critically on the way they exercise their work.     

Al Qaida on the US invasion of Afghanistan in their own words

This article consists of selected translations from captured interviews and dairies of Al Qaida members. The time period covered is from mid-2001 to early 2002 and concerns their operations in Afghanistan. The material clearly conveys a range of emotion, from confident to despondent, as well as efforts to contest the US actions. The first several pages give the reader context and some possible “lessons learned,” but the story(ies) are best told by the Al Qaida members themselves. All names are pseudonyms.     

基于GTST-DMLD-ESD的装备RMS建模仿真

装备的RMS是装备的重要设计参数,是影响战备完好和保障能力的关键因素.引入GTST-DMLD作为主要建模工具,建立起装备系统的RMS描述模型,以ESD为补充和扩展,对维修过程进行建模.并以GTST-DMLD-ESD模型作为装备RMS仿真的核心,对装备RMS仿真模型的总体框架进行了研究,并对各模块进行了较为详细的探讨.