科氏流量计信号相位差测量新算法

对科氏流量计信号进行处理时,传统相位差测量算法存在较大误差。为更好地抑制频谱泄露,提高相位差测量精度,在传统DTFT算法的基础上,通过矩形窗和汉宁窗卷积运算构造出一种新窗——RHC窗。计及负频率成分的影响,提出了一种基于RHC窗的DTFT相位差测量新算法。详细阐述了新算法的原理,并与传统DTFT算法进行了对比仿真,验证了新算法的有效性。     

大气对流层气体组分随高度变化的理论预期

利用大气对流层温度随高度变化的规律,采用局部平衡的多分子混合模型,从理论上论证了对流层气体组分随高度变化的规律,发现大气各主要成分体积分数、分子平均摩尔质量均随高度线性变化,并拟合数值计算结果得到了相关参数。氧气的相对体积分数随高度明显下降,而氮气的相对体积分数却明显上升;但是相比于温度随高度的变化,大气分子平均摩尔质量的改变可以忽略。该理论比以往其他模型预测大气压强随高度变化规律具有更自然、更接近实际的优势。     

气候条件对城市火灾的影响规律

选取样本城市各项火灾数据和气象参数数据,对样本数据进行筛选计算,通过对两者的一元相关性进行研究,得出火灾概率和典型气象参数之间的关系。     

边境地区群体性事件预警指标体系构建研究

科学、可行的指标体系是群体性事件预警的核心。在坚持完备性与最小性原则、科学性与可行性原则、敏感性与动态性原则、全局性与针对性原则的前提下,利用层次分析法、专家调查法,构建了以边境地区经济、社会保障、公共安全维护、民族与宗教、边民心理状况以及周边环境六大因素为支撑的边境地区群体性事件预警指标内容,并形成了6个一级指标,12个二级指标,44个三级指标的边境地区群体性事件预警指标体系。     

A NEW STANDARD FOR PREEMPTIVE MILITARY ACTION AGAINST WMD THREATS

International law clearly requires an imminent threat of attack as a justification for the preemptive use of military force. However, the standard definition of an imminent threat was derived centuries before the development of nuclear, chemical, or biological weapons or ballistic missiles and other delivery systems that can reach their targets in a matter of minutes. Any use of force to alleviate threats posed by weapons of mass destruction (WMD) prior to tactical warning of the actual launch of such weapons falls into the legally and ethically controversial category of “anticipatory self-defense,” leaving decision makers potentially liable to prosecution for war crimes. Effective and ethical enforcement of nonproliferation therefore demands a standard for imminence of threat broad enough to allow military action as a last resort but sufficiently restrictive to prohibit indiscriminate action against suspected WMD programs. Following a critical review of selected literature and cases on preemption, the author proposes a new standard for preemptive military action: the existence of operational WMD, or a clandestine program to develop WMD, in contravention of international law. The author discusses the implications of this new proposed standard, which at the time of writing would permit preemptive attack against WMD-armed terrorist groups but prohibit it against all states except Iran and possibly North Korea.     

Contents and Author Index,Volume 20, 2013

The United States has multiple nuclear detection initiatives to secure against a terrorist nuclear attack, including the Container Security Initiative, installation of radiation detectors at U.S. border points of entry, and establishment of the Domestic Nuclear Detection Office (DNDO). The current nuclear detection system architecture falls short of being able to reliably catch fissile nuclear material in transit, specifically shielded Highly Enriched Uranium (HEU) and Plutonium (Pu), both within the US and abroad. Checkpoints at border crossings can be circumvented, and no adequate system is under development to deter the transport of fissile materials. Using nuclear link-budget calculations, we show why a network relying primarily on handhelds, fixed detectors, and portals is not sufficient. We examine the technical, economic, and operational feasibility of a comprehensive national network incorporating in-vehicle detectors to reliably detect and deter the transport of fissile material inside the vehicle itself.     

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.     

远距离支援压制干扰实施及结果评定方法

远距离支援干扰在现代战争中发挥着重要的作用。为分析远距离支援干扰实施及对被试雷达性能影响,首先根据中心极限定理,推导了靶场试验中检飞航次数的数学模型,然后研究了基于干信比的干扰机飞行航路设计原则,最后通过仿真分析,给出了试验样本数与发现概率和置信区间的关系,讨论了不同航路点上到达被试雷达的干信比和对被试雷达性能的影响,解决了靶场抗干扰试验中试验样本数及试验航路设计等方面问题。     

一种宽带梳状线电调滤波器的设计

提出了一种宽带梳妆线电调滤波器的设计方法,采用四阶变容管加载终端短路式,滤波器输入端配有单级自偏中放电路,在带内起伏较小且在频率低端的损耗也较小。经过测试表明,该滤波器的工作频段为668.6 MHz~1 300 MHz,插损小于6 dB,3 dB带宽小于5%,矩形系数为5时,阻带抑制为45 dB。     

海天背景下舰船可见光图像目标区域定位方法

针对行均值法用于海天背景下舰船目标区域定位可靠性不高、容易受到舰船目标大小和海天背景复杂程度影响的不足,提出一种基于图像行灰度熵的舰船目标区域定位方法。该方法在分析海天背景下舰船目标可见光图像成像特点基础上,结合信息熵理论给出了图像灰度熵及行灰度熵的概念,利用图像行灰度熵描述图像在行方向上的灰度变化程度,选用滑动区间方差搜索策略得到图像行灰度熵曲线的突变区间,从而实现舰船目标区域定位,最后通过实际图像进行了实验验证。实验结果表明,该方法能对舰船目标所在区域有效定位,其准确性及鲁棒性均优于行均值法。