基于CNN的三相逆变器开路故障诊断及其样本条件分析

为了合理选择样本条件以实现高效的智能化诊断,以及克服智能化方法中传统反向传播(back propagation, BP)网络权值较多、局部信息提取能力不足的问题,对基于卷积神经网络(convolutional neural network, CNN)的开路故障诊断方法进行研究,并以典型的三相两电平逆变器为具体对象,着重分析样本时长、样本数量变化时,CNN方法相较于BP网络方法在网络权值数量、训练稳定性、诊断准确率上的量化优势。结果表明,基于CNN的方法可在权值数量远少于BP网络方法的情况下构建深度更深的诊断模型,并在更短样本时长、更少训练样本数量下实现高效、准确的开路故障诊断。     

加权振动烈度在齿轮箱状态监测中的应用研究

针对齿轮箱运行过程中状态监测的性能特征参量及其评价标准的确定问题,研究以齿轮箱振动烈度为性能特征参量,依照国标GB6075—1985来判定齿轮箱运行状态,提出在特征频率处计算振动烈度,即加权振动烈度,以此作为监测量来判定齿轮箱性能状态,并可以对故障进行初步定位。     

基于比例危险模型的船用柴油机视情维修决策

针对船用柴油机视情维修决策问题,采用威布尔比例危险模型描述了系统状态与故障率之间的关系,利用核主成分分析对协变量进行了去相关和约简处理,以平均费用最小为决策目标,建立了视情维修的最优维修策略模型,并根据设备当前状态信息来判断是否需要进行维修。实例分析表明：该方法有效融合了历史故障信息和运行状态信息,提高了柴油机可用度,降低了维修保障费用。     

卫星对水面航渡阶段潜艇的探测概率分析

利用遥感手段实施对潜探测已对潜艇保持隐蔽性构成了严重威胁。基于对各种类型相关卫星的参数和探测能力的分析,计算出在不同气象条件下、不同出航时间时卫星对远航潜艇的水面航渡阶段的的探测概率。这对分析潜艇远航暴露的原因、制定合理的远航计划都具有一定的参考价值。     

分布式监测系统故障诊断功能模型分析

分布式监测系统长时间的连续监测,累计的数据量非常可观,为了数据实时传输及节省传输成本,对监测的数据现场预处理,采取一定的方法压缩数据量非常必要.目前,针对状态数据传输过程中的数据压缩与传输效率的研究还很少,一般采用黑匣子功能模型或白匣子功能模型,虽然具有减少数据冗余的作用,但是没有考虑数据流本身冗余特性,提出基于数据压缩的分布式监测系统功能模型,提高了通信速度和可靠性,满足了实时传输的要求.     

考虑气象因素的飞机空战能力评估模型

针对指数法评估飞机空战能力的不足,研究了气象环境对飞机作战效能的影响,分析了综合指数模型中飞机操纵性能、态势感知能力、火力性能受不良气象条件的影响,建立了不良气象环境下的飞机系统空战效能评估模型。最后以3种机型的空战能力评估为例进行计算,验证了所建模型是合理、可行的。     

An Empirical Analysis of the Arms Race Between South and North Korea

This study analyses an arms race between South and North Korea over the period 1963–2000. Despite the strategic importance of the Korean Peninsula, the arms race between South and North Korea has rarely been studied. In this study, the South–North arms race is empirically estimated using Richardson’s action–reaction model. The pattern of South–North arms race between the Cold War (1963–1989) and the post‐Cold War eras (1990–2000) as well as the existence of an arms race is examined comparing both countries’ defence spending, number of military personnel and tactical aircraft.     

An analysis of the Washington naval agreements and the economic provisions of arms control theory

During the Cold War, two contending hypotheses dominated theories concerning the economic impact of anus control. The first suggested that when certain prerequisites were fulfilled, arms control agreements served to promote lasting reduction in military spending. The second asserted that instead of promoting savings, arms control encouraged diversion of resources to more advanced and expensive weapons, thus driving defense spending higher. Through the examination of the impact of the Washington Naval Agreements on naval expenditure during the 1920s, this paper provides empirical evidence to support the latter of these competing hypotheses. The United States, Great Britain, and Japan all realized economic savings after signing the Washington Naval Agreements. However, these savings soon eroded as the powers developed more advanced weapons‐systems.     

One Step Forward,Two Steps Back

This article explores the potential impact of U.S. disarmament leadership on the nuclear diplomacy of North Korea and Iran, the “defiant states.” The first part of the article introduces the concept of “interaction capacity,” which measures a state's integration into international society, based on its physical communication systems and its adoption of shared norms. The theory predicts that lower levels of interaction capacity will generate a greater propensity for nuclear defiance, as the affected states reject and try to resist integration pressures. In the second and third parts of the article, this conceptual framework is applied to the cases of North Korea and Iran. The analysis suggests that efforts to reassert U.S. disarmament leadership could increase the alienation of North Korea and Iran, leading to provocation and escalation of nuclear tensions. The final part of the paper explores the policy implications of this analysis for the potentially defunct six-party talks, for hopes of renewed negotiations with Iran, and for the 2010 Review Conference of the Treaty on the Non-Proliferation of Nuclear Weapons.     

水下监测系统中的特殊均匀圆阵特性分析

一种特殊的均匀圆形阵列(SUCA)安装在水下监测系统中的浮体系统上。针对SUCA的特殊性,建立了SUCA的模型,运用模式空间理论推导出其方向图公式,并在此基础上对其半功率波束宽度和无模糊条件进行了研究和分析。通过与均匀圆形阵列(UCA)进行比较,得出结论:SUCA半功率波束宽度略大于UCA,并且其无模糊条件比UCA范围更广。研究表明SUCA的性能与UCA相似,具有工程实用价值。