虚拟仪器的IMU故障诊断系统

虚拟仪器是基于计算机的数字化测量仪器,利用虚拟仪器实现功能模拟,以达到检测故障的目的.针对惯性定位定向系统技术含量高,故障诊断困难的特点,分析了惯性定位定向系统的故障检测原理,利用Labview设计了虚拟仪器,构建了故障诊断系统,通过试验证明该系统能够实现惯性定位定向系统的故障定位.     

基于虚拟仪器的通信设备自动测试系统设计

介绍了基于虚拟仪器的通信设备自动测试系统设计思路及方法, 给出了此类自动测试系统的硬件平台,重点介绍了虚拟仪器在自动测试系统中的应用以及对通信设备自动测试的软件体系结构设计。     

数字示波器网络化校准测试技术研究

在对网络化校准技术深入研究的过程中,对网络化校准系统体系结构与构建、系统应用软件设计等关键技术进行了研究,以此为基础设计了一个网络化示波器校准系统并进行了实际测试分析。     

虚拟仪器与C3I系统检测维修站

简要地介绍了虚拟仪器的体系结构,并探讨了一种基于VXI总线下用基本硬件和图形化编程语言设计虚拟仪器的方法.同时还指出了在当前C3I系统的检测中,迫切地需要淘汰常规的仪器,采用虚拟仪器来进行检测.     

虚拟仪器测试系统简介

本文介绍了虚拟仪器的结构和特点,通过对PCI、PCI、VXI三种不同总线主要性能的比较,指出了基于三种不同总线的虚拟仪器测试系统的特点及应用范围。     

低频UWBSAR辐射校准模型

低频超宽带合成孔径雷达(Ultra Wide Band Synthetic Aperture Radar,UWBSAR)的辐射校准是系统研制和应用过程中必须面对的课题。低频UWBSAR的特点使得常规SAR辐射校准技术不再适用。充分考虑校准参数随频率和方位角的变化,给出适合该系统的辐射校准方法,得到低频UWBSAR图像辐射校准模型。利用该模型,对系统辐射校准误差进行了分析。     

火炮膛压测试系统的环境因子校准技术

放入式电子测压器用来测量火炮膛压,用测压器静态校准的灵敏度直接用于动态压力的测量会给测量结果带来很大误差,为了减小测试环境对测压器的影响,提出了环境因子校准的思想,研制了能模拟火炮膛内高温高压环境的模拟膛压发生器,建立了环境因子校准系统,分析了环境因子校准的必要性,介绍了校准系统的数据处理方法.实炮测试结果表明经过环境因子校准的测压器的测试数据稳定性好,置信度高.     

一种六加速度计无陀螺惯性导航系统安装误差校准方法研究

针对加速度计安装方向和位置向量补偿的问题,理论上推导了一种六加速度计无陀螺惯性导航系统安装误差校准方法,通过重力效应进行加速度计方向向量的校准,通过载体旋转产生的向心加速度进行位置向量的校准,然后利用校准的结果进行加速度计输出补偿,并进行了计算机数字仿真。仿真结果表明,经加速度计安装校准和补偿,系统精度可提高600倍以上,验证了该方法的有效性。     

基于辐照度标准传递的辐亮度校准系统

介绍了一种新型辐亮度校准系统,通过溯源至国家辐照度标准,构建了军用光辐射校准平台。对系统的测量不确定度分析表明,该系统可以满足装备计量保障对测试不确定度比的通用要求,适用于装备专用检测设备的辐亮度校准。     

一种近距离宽带CSAR成像系统通道均衡方法

在传统的外部参考校准方法基础上,提出了一种利用校准金属板成像实现近距离宽带毫米波CSAR三维成像系统中多通道幅度和相位均衡的方法。该方法分为两步完成毫米波天线阵列的幅度和相位校准。首先,采用外部参考的校准方法,利用校准金属板来完成天线阵列的幅度和相位粗校准,然后,借助空间频率内插的波前重构算法完成对校准金属板的三维空间重构,通过三维空间散射数据切面图的自聚焦来修正天线阵列的相位实现相位的精校准。通过搭建的近距离毫米波CSAR三维成像系统,验证了该通道均衡方法的可行性和有效性。     

What Goes Up Must Come Down: Military Expenditure and Civil Wars

Abstract

This paper examines the impact of civil war on military expenditure. We employ two measures of military expenditure: the share of military expenditure in general government expenditure and the logarithm of military expenditures. We would reasonably expect a priori that military expenditure as a share of general government expenditure increases during a civil war and that such increases would taper off over the duration of a civil war. We also explore whether the termination of a civil war induces a decline in the share of military expenditure as a share of the general government expenditure in the short-run. We find evidence the of share of military expenditure increases during a civil war and falls in the year succeeding the end of a civil war, and, in particular, if a war ends in a peace treaty. The level of military expenditures, however, rises during civil wars and does not appear to decline in the short-term after the end of a civil war.     

Scheduling policies for an antiterrorist surveillance system

This article concerns scheduling policies in a surveillance system aimed at detecting a terrorist attack in time. Terrorist suspects arriving at a public area are subject to continuous monitoring, while a surveillance team takes their biometric signatures and compares them with records stored in a terrorist database. Because the surveillance team can screen only one terrorist suspect at a time, the team faces a dynamic scheduling problem among the suspects. We build a model consisting of an M/G/1 queue with two types of customers—red and white—to study this problem. Both types of customers are impatient but the reneging time distributions are different. The server only receives a reward by serving a red customer and can use the time a customer has spent in the queue to deduce its likely type. In a few special cases, a simple service rule—such as first‐come‐first‐serve—is optimal. We explain why the problem is in general difficult and we develop a heuristic policy motivated by the fact that terrorist attacks tend to be rare events. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009     

Deterrence of Nuclear Terror

Nuclear proliferation, lax security standards in the storage of fissile materials, and international apathy in the prosecution of terrorists make nuclear terror a serious threat to the United States and its allies, yet no doctrine of retaliation has been established. To decrease the probability of terrorist use of nuclear weapons, a doctrine of retaliation—a negligence doctrine—should be considered. If the United States can distinguish whose fissile material was used for a nuclear terror event, a negligence doctrine would prescribe retaliation against that state. Where the proximate cause—terrorists—is unavailable for deterrent retaliation, deterring an accessible mediate cause—a state that has failed to adequately secure its fissile material—is one of a few effective alternatives. In the absence of such a negligence doctrine, the United States and its allies are increasingly vulnerable to a nuclear terror attack and the ensuing negative consequences.     

The Canary in the Nuclear Submarine: Assessing the Nonproliferation Risk of the Naval Nuclear Propulsion Loophole

ABSTRACT

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) allows states to exempt nuclear material from international safeguards for use in nuclear submarine programs. This material, however, could be diverted for nuclear weapons purposes without the knowledge of inspectors, creating a potentially dangerous loophole in the treaty. This article argues that exercising that loophole today would amount to admitting a nuclear weapon program, making it a particularly poor pathway to a weapon for a potential proliferant. Still, if states like Brazil ultimately exempt nuclear material from safeguards for a nuclear submarine effort, they could set a dangerous precedent that makes it easier for others to use the loophole as a route to a nuclear weapon capability. There are several policy options available to mitigate the damage of such a precedent; most promising is the prospect of a voluntary safeguards arrangement that would allow international inspectors to keep an eye on nuclear material even after it has been dedicated to a naval nuclear propulsion program.     

关于学校定位的理性思考

每一所学校的建设与发展,都离不开先进、准确、合理的学校定位。学校定位的准确与否,直接关系着学校办学的前途和命运。学校定位对学校办学行为起着规范、约束和自我评估的作用。能否为自己的学校建设与发展找准定位,是衡量一所学校高层决策水平高低和教学工作水平优劣的重要依据。所以,要准确把握学校定位的含义、依据、内容及特征。     

The 1983 Nuclear Crisis – Lessons for Deterrence Theory and Practice

This article distills insights for the scholarship of deterrence by examining the 1983 nuclear crisis – the moment of maximum danger of the late Cold War. Important contributions notwithstanding, our understanding of this episode still has caveats, and a significant pool of theoretical lessons for strategic studies remain to be learned. Utilizing newly available sources, this article suggests an alternative interpretation of Soviet and US conduct. It argues that the then US deterrence strategy almost produced Soviet nuclear overreaction by nearly turning a NATO exercise into a prelude to a preventive Soviet attack. Building on historical findings, this article offers insights about a mechanism for deterrence effectiveness evaluation, recommends establishing a structure responsible for this endeavor, and introduces a new theoretical term to the strategic studies lexicon – a ‘culminating point of deterrence’.     

Orbix的分布对象计算性能分析

通过一个计数器的分布对象设计及Orbix实现,阐明了先进的分布对象技术标准CORBA的核心概念以及符合CORBA2．0标准的中间件产品Orbix的分布对象设计和实现过程,通过计算比较并分析了Orbix在单机和网络分布环境下实现效率的差异,并提出了用单机模拟网络环境下分布对象实现效率的方法．     

Modeling and analysis of vessel casualties resulting from tanker traffic through narrow waterways

In this paper, we present a physics-based stochastic model to investigate vessel casualties resulting from tanker traffic through a narrow waterway. A state-space model is developed to represent the waterway and the location of vessels at a given time. We first determine the distribution of surface current at a given location of the waterway depending on channel geometry, bottom topography, boundary conditions, and the distribution of wind. Then we determine the distribution of the angular drift for a given vessel travelling at a given location of a waterway. Finally, we incorporate the drift probabilities and random arrival of vessels into a Markov chain model. By analyzing the time-dependent and the steady-state probabilities of the Markov chain, we obtain risk measures such as the probability of casualty at a given location and also the expected number of casualties for a given number of vessels arriving per unit time. Analysis of the Markovian model also yields an analytical result that shows that the expected number of casualties is proportional to square of the tanker arrival rate. We present our methodology on an experimental model of a hypothetical narrow waterway. © 1999 John Wiley & Sons, Inc. Naval Reseach Logistics 46: 871–892, 1999     

The Pattern 1853 rifled musket — Genesis

Abstract

The fragmentary remains of a sixteenth century bronze gun discovered in Kilrenny, Scotland, are discussed. Although the recovered fragments comprise only a small proportion of the gun a consideration both of the findspot and the fragments together can provide a substantial understanding of the weapon when complete. Stylistically, the fragments are suggestive of a continental import intended to augment local production, and analysis suggests a poor choice of alloy on the part of the founder may have contributed to the weapon's destruction. The archaeological and historical landscape in which the fragments were found in turn offers a context in which to analyse the weapon's use and importance.     

铜冶炼炉溜槽上方钢梁温度分布研究

为了对有色冶炼厂房框架钢梁耐火稳定性评估提供条件,根据冶炼铜实际工况建立计算模型,数值研究钢梁温度分布,结果表明:在加热初期,钢梁的平均温度和最高温度不断上升,经历10个升温-降温周期后,钢梁的最高温度稳定在220℃左右。钢梁温度与梁的截面尺寸和形状、梁计算截面位置、溜槽与梁相对位置等众多因素有关。梁与溜槽距离越大,梁截面高度越大,翼缘宽度越小,最高温度与平均温度越低;梁长度大小不影响梁最高温度,但梁长度越大平均温度越低。