基于上下文的快速自适应运动估计算法

高效的运动估计算法是实时视频编解码技术的研究重点。为降低视频编码中运动估计的高计算复杂度问题,提出了基于上下文的快速自适应运动估计算法。该算法在运动估计过程中引入了次最佳匹配点,并且使用了一种基于平行四边形模式的方向性搜索策略。该算法的基本思想是:在块运动矢量估计过程中,利用前面搜索步中得到的块运动矢量及次最佳匹配点与最佳匹配点之间的位置关系,自适应选择一种平行四边形搜索模式,并确定下一步搜索的方向,进行更精确运动矢量的搜索。实验结果表明,该算法有效降低了视频压缩编码中运动估计的运算复杂度。     

视频编码标准H．264运动矢量搜索算法

高清视频的信息量巨大，传输比较困难。 H．264作为视频压缩的主流标准，可以有效去除视频的冗余信息，提高视频的网络传输能力。针对H．264中运动估计算法耗时严重的问题，提出一种新的X型搜索算法。 X型算法由粗到细地进行搜索，先以X型快速搜索确定运动矢量的可能范围，然后在可能范围内进行局部全搜索，最终确定运动矢量。试验结果表明，X型搜索能够在保证视频质量的情况下大幅度缩短编码时间，有效提高运动估计算法的效率，兼顾了速度与精度，为高清视频的实时传输提供了保障。     

基于DM642的电子稳像算法研究

基于格雷编码位平面匹配算法,给出了该算法实现的原理、优点,介绍了该算法实现的几个步骤:图像预处理,区域运动矢量计算,全局运动矢量计算,运动补偿;依据DM642核心芯片,设计了一个基本DM642的视频处理系统;在基于MATLAB的软硬件环境里,设计了一个仿真系统,给出了仿真系统的各个框图,采用MATLAB语言编写了一个仿真程序,对一段视频进行了处理,在仿真环境下基本实现了实时处理。最后对仿真结果进行了评测,给出了几种测试方法。     

基于活动轮廓和水平集的多帧运动检测

研究了活性轮廓/水平集优化的分割序列的处理方法,建立一种时空模型,把视频分割问题简化为运动参数估计和分割曲面估计交叉的问题,将所得到的对象分割处理模型公式化,再用快速步进法将公式离散化。并对两帧和多帧的处理方法进行了研究,运用实例对两种方法进行了比较,结果表明多帧方法具有较高的有效性。     

低信噪比下融合随机共振的运动目标检测算法

为提高智能视频监控系统中运动目标检测算法在低信噪比条件下的鲁棒性,结合混合高斯背景建模算法和随机共振原理实现一种低信噪比下的运动目标检测算法。算法根据混合高斯背景模型对当前帧生成目标概率灰度图,在本文定义的性能评价函数下,通过向该概率灰度图添加噪声使得评价函数最优化从而达到随机共振,对该随机共振灰度图进行阈值分割得到输出的检测目标。针对昏暗、大雾和红外视频分别进行了实验,证实了本文算法的有效性同时也显示本文算法相对于普通背景差算法性能获得了明显提升。     

Wyner-Ziv系统中MCTI边信息生成算法

Wyner-Ziv视频编码的特点是编码简单、解码复杂,适用于无线通信系统中资源受限的视频编码设备。在Wyner-Ziv视频编码系统中,为获得高质量的解码图像,边信息构造算法起着重要作用。文章首先利用前向和后向运动估计得到最初的运动矢量,然后采用双向运动估计和运动补偿时域插值方法生成边信息,针对边信息中出现的块效应和重叠现象,利用加权重叠块运动补偿技术加以解决。实验结果表明,所提出的加权运动补偿算法要优于已有的双向运动补偿算法,且可获得较理想的边信息重构。     

基于模糊C-划分和3D小波变换的视频编码方法

在传统矢量量化的基础上,引入噪声模型的影响,结合模糊数学理论,提出了一种基于模糊C-划分的混合噪声模型的矢量量化方法,并将其应用到视频编码中。文中视频编码方法采用了运动补偿与3D小波变换相结合。主要对基于模糊C-划分的混合噪声模型的矢量量化进行了分析。实验结果表明,该方法在视频压缩中具有良好的效果。     

一种改进的扩展旋转矢量姿态算法

在分析扩展旋转矢量姿态算法的基础上,基于典型圆锥运动理论以及迭代算法的思想推导了一种面向四子样的改进扩展旋转矢量优化算法.给出了较为详细的算法推导过程和具体公式.为检验改进算法的有效性,先后采用传统的四元数法、扩展旋转矢量法以及改进算法,对载体的典型圆锥运动进行了计算机仿真研究.结果表明,该优化算法不仅改变了捷联惯性导航系统中陀螺子样的利用方式,而且提高了系统旋转矢量的计算精度以及姿态算法的实时性.     

联合特征累积分析的压缩域运动对象检测

依据H.264压缩域中能够反映景物运动变化的MV和DCT系数特征,本文提出了一种多特征联合累积分析的压缩域运动对象检测方法。该方法对压缩码流中各宏块的运动信息进行时空域滤波,并使用雅克比矩阵描述全局运动参数和宏块MV之间的关系,简化参数求解过程,通过比较局部运动和全局运动之间的差异初步检测运动对象;选取宏块周围可靠的运动特征用于宏块DCT系数能量的投影累积,并通过熵能原理在压缩域中选取各个宏块的自适应阈值,检测运动对象的边缘及纹理显著区域;通过一定的逻辑准则将MV和DCT系数的检测结果结合起来,最终检测出视频中运动对象。实验结果表明,本文算法可准确地检测压缩视频中的运动对象,且检测结果具有较高的查全率和查准率。     

基于单应轨迹的视频实时稳像算法

针对视频稳像中实时任务的需求特点,提出一种基于单应轨迹的视频稳像算法。估计序列图像帧间的单应变换,并将该变换作用于图像窗口的4个角点,从而对每帧图像产生4个短的单应轨迹以代表视频短时间内的运动。利用关联卡尔曼滤波器以一种连续方式对不同帧的单应轨迹进行平滑。对图像合成采用包括性和相似约束以提高结果视频的可观性质量。该算法以在线方式工作,消除了缓存输入图像帧导致的延迟,具备不依赖于复杂的3D重建和长距离特征跟踪的优点,并有效避免了单应模型表达视频运动模型的误差积累问题。实验表明该算法能够有效对包含2D和较复杂3D场景的视频进行稳像,并且能够达到实时处理速度。     

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.     

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。     

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.     

Does Intent equal Capability? Al-Qaeda and Weapons of Mass Destruction

The prospect of terrorists deploying weapons of mass destruction (WMD) is often referred to as the foremost danger to American national security. This danger has become more realistic because of al-Qaeda's expanding global network and the expressed willingness to kill thousands of civilians. In the past four years, numerous media reports have documented the group's ongoing quest for WMD capabilities; many reports have detailed al-Qaeda members’ attempts to manufacture or obtain certain chemical, biological, radiological, and nuclear (CBRN) agents to use in WMD against targets in the West and the Middle East. Yet the question remains: Does al-Qaeda's current WMD capability match its actual intent? While most studies of the group have focused on its explicit desire for WMD, allegations of CBRN acquisition, and the killing potential of specific CBRN agents, few open-source studies have closely examined the evolution of al-Qaeda's consideration of WMD and, most notably, the merit of actual CBRN production instructions as depicted and disseminated in the group's own literature and manuals. The following report will examine the history of al-Qaeda's interest in CBRN agents, the evolution of the network's attitude toward these weapons, and the internal debate within the organization concerning acquisition and use of WMD. More so, the following research will assess the validity of actual CBRN production instructions and capabilities as displayed and disseminated in al-Qaeda's own literature and websites.     

Late Medieval Lance Use: Mounted Combat and Martial Arts in Western Europe from the 14th to the 16th Century

Despite the lance’s status and the amount of attention the couched lance has received in historiography, study of its martial art has been neglected. The various lance types and techniques used by western European cavalry have only recently begun to receive scholarly attention. Additionally, Medieval European lance use has too often been studied in isolation, without an adequate understanding of the idiosyncratic and asymmetrical dynamics of mounted combat. Although the charge with the couched lance was a valid tactic, it was only one of many. Light and heavy lances were used in one hand or two to trip, block, unhorse, and wrestle. These techniques were governed by the harsh laws of distance, speed, impact, iron, and asymmetry. By utilizing the surviving Fechtbücher and several Peninsular and Near Eastern sources, a brief foray into the diverse techniques of lance use and their purposes has been attempted here.     

A model for geographically distributed combat interactions of swarming naval and air forces

This article describes the Distributed Interaction Campaign Model (DICM), an exploratory campaign analysis tool and asset allocation decision‐aid for managing geographically distributed and swarming naval and air forces. The model is capable of fast operation, while accounting for uncertainty in an opponent's plan. It is intended for use by commanders and analysts who have limited time for model runs, or a finite budget. The model is purpose‐built for the Pentagon's Office of Net Assessment, and supports analysis of the following questions: What happens when swarms of geographically distributed naval and air forces engage each other and what are the key elements of the opponents’ force to attack? Are there changes to force structure that make a force more effective, and what impacts will disruptions in enemy command and control and wide‐area surveillance have? Which insights are to be gained by fast exploratory mathematical/computational campaign analysis to augment and replace expensive and time‐consuming simulations? An illustrative example of model use is described in a simple test scenario. © 2016 Wiley Periodicals, Inc. Naval Research Logistics 63: 562–576, 2016     

Thomas Firth and Sons – Steelmakers to the Arms Industries. Part 2: Heavy Armaments

Firth’s were the first of the Sheffield steel makers to enter the field armaments. Their involvement with Colt has been outlined in an article in the journal of the Colt Collectors Association in America and their activities as steelmakers to the small-arms industries has been covered in a previous issue of this Journal. This article gives a brief overview of their involvement as manufacturers in the field of heavy armaments, being the first to make all-steel guns and their evolving role in the use of steel for ordnance, culminating in the displacement of wrought iron by the adoption of steel for ordnance manufacture by the Royal Gun Factory in the 1880s. It also highlights their development of stainless steel in this context.     

Reviews

Douglas S. Derrer, We Are All the Target: A Handbook of Terrorism Avoidance and Hostage Survival. Annapolis, MD: US Naval Institute Press, 1992. Pp. x+135, notes, index. $14.95. ISBN 01–55750–150–5

Ian Knight, Zulu: Isandlwana and Rorke's Drift, 22–23 January 1879. London: Windrow & Greene, 1992. Pp.136, 150 illus., incl 8 colour plates, maps, biblio. £35. ISBN 1–872004–23–7

Ian Knight, By the Orders of the Great White Queen: Campaigning in Zululand through the Eyes of the British Soldiers, 1879. London: Greenhill Books and Novato: Presidio Press, 1992. Pp. 272, 17 illus., 1 map. £18.95. ISBN 1–85367–122–3

Manfried Rauchensteiner and Erwin A. Schmidl (eds.), Formen des Krieges: vom Mittelalter zum ‘Low‐intensity’ Conflict’. Graz : Verlag Styria, 1991. Pp.208. DM35. ISBN 3–22–12139–7

Harold J. Kearsley, Maritime Power and the Twenty‐First Century. Dartmouth: Dartmouth Publishing Company, Limited, 1992. Pp.xv + 203, 13 diagrams, index. £32.50. ISBN 1–85521–288–9