基于云分类器的液体火箭发动机故障诊断方法

本文首先将液体火箭发动机故障诊断问题转化为故障特征的模式分类问题,然后针对当前模式分类方法难以处理不确定性信息、属性特征空间的划分过硬等缺陷,结合云模型和云变换研究,提出了一种基于云分类器的液体火箭发动机起动过程故障诊断方法。历次试车数据的验证结果表明,该方法能够及时准确识别发动机起动工作过程中的故障模式。     

基于层间嵌入式多级支持向量机的特征选择

针对多故障样本一次性映射之后分类不理想,研究了多级层次式支持向量机,应用UCI数据仿真,结果表明该方法缩短了训练时间、提升了测试准确率、改善了样本的可分类性。由于误差积累,在此基础上,提出了层间嵌入式多级支持向量机,采用Abalone数据仿真,结果表明分类精度有所提高并减少了分类步骤。结合ReliefF算法,对制导设备的故障特征参数进行了选择。     

萤火虫优化的异构集成学习网络入侵检测方法

在网络入侵检测中单独使用一种机器学习方法检测存在盲区,检测精度较低,提出一种基于GSO优化权值的异构集成学习入侵检测算法.在构造基分类器中,通过对样本集的采样和特征集的选择增大各个基分类器样本间的差异性;通过不同学习算法对样本集的学习增强基分类器的差异度,通过加权方式集成得到检测结果.在设计权值时,引入萤火虫优化算法,对各个基分类器的分类结果权值进行优化.在通用数据集和CSE-CIC-IDS2018数据集上的实验,表明提出的方法能够有效提高检测的精度,降低误报率和漏报率.     

基于小波包和支持向量机的舰用发动机故障诊断

舰用发动机是一个复杂的大系统,由于受到海洋恶劣气候的影响,其故障发生的概率大大增加,因此,对舰用发动机故障诊断进行研究具有重大实际意义。以舰用发动机的主泵轴承为例,提出了基于小波包和支持向量机的故障诊断方法。首先采用振动加速度传感器获取轴承的振动信号,然后对采集数据进行多层小波包分解,求各频带信号能量,形成各种故障模式下的特征向量。将形成的故障特征向量训练集输入到支持向量机,通过训练建立诊断分类器,并运用测试数据对建立的诊断分类器进行测试。实验结果表明,该方法可以很好地实现舰用发动机故障诊断效能,具有很好的工程应用前景。     

基于记忆提炼的对比度量增强在线类增量学习图像分类方法

图像分类中类增量学习具有知识灾难性遗忘现象,现有的基于经验回放方法着重考虑的是记忆库的更新和采样方式,忽略了新旧样本之间的特征关系。为此,提出了一种基于记忆提炼的对比度量增强在线类增量学习图像分类方法(cME²),设计了两种新的正负样本对,对旧样本信息进行了加强重复再利用,强化了模型对冗余特征和共性特征的表达能力,基于最近邻均值分类器改善了嵌入空间中的样本分布合理性。最后,通过对比实验和消融实验验证了所提方法的有效性和高效性。     

基于自训练EM算法的半监督文本分类

为了提高计算效率,提出基于自训练的改进EM算法STEM。在每步迭代的E-step中,将中间分类器最有把握对其类别进行预测的未标注样本转移至标注样本集,并应用到M-step中进行下一个中间分类器的训练,从而引入了利用中间结果的自训练机制。文本分类实验表明STEM算法在大部分情况下的分类准确性都高于EM,并通过减少迭代提高了分类器学习的计算效率。     

火箭发动机故障检测的快速增量单分类支持向量机算法

为解决液体火箭发动机故障诊断正负样本不平均问题,以及实现发动机稳态工作段自适应故障检测,建立了基于快速增量单分类支持向量机的异常检测模型。采取特征工程方法,对传感器获得的多变量时间序列进行特征提取。通过增量学习方法,对单分类支持向量机模型进行改进,并应用于液体火箭发动机异常检测,使单分类支持向量机检测模型具备对不同台次、不同工况的自适应性,提高了模型的计算速度。对多台次热试车数据的分析结果表明,该模型十分有效,训练速度快,具备实用价值。     

基于概率神经网络的设备故障诊断及仿真分析

针对某些难于建立准确数学模型的复杂系统,用神经网络的方法进行故障诊断有其独特的优越性.首先分析了概率神经网络(PNN)的基本结构及其训练算法,建立了某型航空发动机故障分类的概率神经网络模型,通过对该设备故障进行定性诊断,对比分析了概率神经网络与常用的误差反向传播神经网络(BPNN)分类模型对各类故障的分类效果.仿真表明,基于PNN模型的分类方法在分类速度、精度和泛化能力方面均优于基于BPNN的模型,是一种有效的故障分类方法.     

一种综合使用支持向量机和遗传算法的隐藏图像检测方法

提出了一种新的基于遗传算法和支持向量机的隐藏图像检测方法。用遗传算法进行图像特征选择，采用支持向量机作为分类器，将支持向量机的分类效果作为适应度函数值返回，指导遗传算法搜索最优的特征，移除图像的不相关特征和冗余特征，提高了学习效率。实验结果表明，与仅采用支持向量机分类但未进行特征选择的隐藏检测方法相比，本方法能有效地提升分类器性能。     

一种基于模糊竞争网络的主动声纳目标分类器

提出了一种基于模糊竞争网络的主动声纳目标分类器。该分类器结构简单,学习速度快,仅用少量样本进行训练便可获得良好的推广性能．便于实时学习和应用。通过对模式属于各类别的隶属度的分析,可以知道判决的可靠性,具有较好的应用价值。     

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).     

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.     

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.     

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.     

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.     

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.     

Cyber sheiks and grassroots jihadis: the war in Syria and the devolution of the Bosnian Salafi communities

ABSTRACT

What was the scope of the Bosnian jihadi participation in the war in Syria? Did the Bosnian volunteers tend to join one particular faction? Why did the Bosnian youngsters decide to join the holy war in the Levant? Was this an organized and hierarchical process or was this a grassroots movement? Last, were all the Salafis in Bosnia supportive of this dynamic or did this process cause internal frictions? These are some of the questions that this research will try to answer.     

Country survey XVI the defence sector in the economy of a declining superpower: Soviet Union and Russia, 1965-2001

The Soviet Union was able to develop a large military-industrial complex and become the world's second superpower despite deficiencies in its centrally planned economy because defence was given high priority status and special planning, rationing and administrative mechanisms were used to attain national security objectives. However, in the period 1976-85 the effectiveness of priority protection diminished and defence institutions experienced more of the problems typical of the shortage economic system. The heavy defence burden also created growing difficulties for the civilian economy. The attempts by the Gorbachev government to reform the defence sector and improve defence-economic relationships during perestroika (1985-91) uniformly failed. For most of the transition period, the Russian military-industrial complex has been adversely affected by its low priority status, cuts in defence spending, instability of the hybrid politico-economic system, and negative growth of the economy. The armed forces and defence industry have been reduced in size and their outputs of military services and equipment have fallen to low levels. Nevertheless, the Russian armed forces still have over one million troops, significant stocks of sophisticated conventional weapons, and a large nuclear arsenal. The government of President Putin has raised the priority of the defence sector, increased real defence spending, and adopted ambitious plans to revive Russian military power. It is likely, though, that tight resource constraints will hamper efforts to reform the armed forces and to upgrade weapons. By 2010 Russia will be an important, but not dominant, military power in Eurasia.     

Traffickers,terrorists, and a ‘new security challenge’: Russian counternarcotics strategy and the Federal Service for the Control of the Drugs Trade

The collapse of the Soviet Union precipitated the massive expansion of drug use and trade in Russia. The country now has one of the largest populations of injecting drug users in the world and has become the largest single-country market for Afghan heroin. In 2003 the Federal Service for the Control of the Drugs Trade was created to coordinate a comprehensive counternarcotics strategy appropriate to the scale of this threat. The service continues to face a number of challenges in its early stages of development. However, it has made considerable advances in improving responses to large-scale organised crime and in building international cooperation.