An MX/G/1 queueing system with disasters and repairs under a multiple adapted vacation policy

We consider a queueing system with batch Poisson arrivals subject to disasters which occur independently according to a Poisson process but affect the system only when the server is busy, in which case the system is cleared of all customers. Following a disaster that affects the system, the server initiates a repair period during which arriving customers accumulate without receiving service. The server operates under a Multiple Adapted Vacation policy. The stationary regime of this process is analyzed using the supplementary variables method. We obtain the probability generating function of the number of customers in the system, the fraction of customers who complete service, and the Laplace transform of the system time of a typical customer in stationarity. The stability condition for the system and the Laplace transform of the time between two consecutive disasters affecting the system is obtained by analyzing an embedded Markov renewal process. The statistical characteristics of the batches that complete service without being affected by disasters and those of the partially served batches are also derived. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 171–189, 2015     

多准则下反导作战单、多遭遇点预测模型

整个反导射击过程可以简单看作一个基于预测的遭遇点起始的,不断重复、修正的过程。分析遭遇点预测的时间和空间前提,并给出遭遇点预测的3个基本准则;在多准则下建立了单遭遇点预测模型,给出了模型公式中未知量的转化方法;分射击-观察-射击和射击-射击两种情况建立了多准则下多遭遇点预测和优化模型,并给出了拦截弹最晚发射时间的计算方法;就观察时机对遭遇点预测的影响进行了分析与建模。部分研究属于探索性的研究,相关结论对指控模型开发和实施连续反导,从方法和作战理念方面提供了一些参考。     

微波脉冲对硅基双极型晶体管的损伤特性

利用微波脉冲注入实验平台,对硅基双极型晶体管低噪声放大器进行了损伤效应实验。在微波脉冲对硅基双极型晶体管低噪声放大器损伤的失效分析中,当低噪声放大器增益下降大于10d B时,发现硅基双极型晶体管出现了永久损伤。通过对比测量硅基双极型晶体管损伤前后的电特性以及利用扫描电子显微镜观测损伤后晶体管的微观特性发现:硅基双极型晶体管被微波脉冲损伤后,基区的硅材料烧蚀导致发射结和集电结短路,不再具有PN结特性,导致器件失效。     

适用于海底观测网络的恒流远供系统可靠性分析方法

以水下单元的短路/开路故障模式为基础,提出一种分析缆系海底观测网络恒流远供系统可靠性的方法。根据系统供电和结构特性,将系统分成不同的供电链路和链路段。详细研究处于不同位置的各种水下单元发生故障时,对链路和观测设备的供电状态的影响。归纳导致系统和各链路无法正常导通、观测设备无法得到供电的状态情况,分析不同故障状态发生的概率,进而得出求解系统、供电链路与供电设备的供电可靠度的方法。通过算例分析,进一步梳理了3种供电可靠性的共性规律,说明在设计和建设恒流远供系统时,应综合考量这3种供电可靠性。     

基于正交试验法的冗余捷联惯组故障诊断实验方法研究

冗余捷联惯组是运载火箭控制系统的重要设备,需要对其进行故障检测和隔离以保证系统正常工作,所应用的故障检测算法需要进行有效性评估。由于惯组器件配置和故障形式的多样性,所有故障情形进行逐一测试不可能的,因此提出利用正交试验法安排实验,对广义似然比故障检测算法进行性能检测。试验结果表明应用正交试验实现了故障情形的良好覆盖性,有效减少了试验次数,并且从测试数据中验证了故障检测算法的有效性。     

面向通信信号调制识别的半监督生成对抗网络框架

针对只有少量标签数据的弱监督条件下现有调制信号识别模型准确率较低的问题,提出基于生成对抗网络的半监督学习框架。该方法通过对通信信号进行冗余空域变换,使其在适应生成对抗网络模型的同时保留丰富的信号相邻特征;通过梯度惩罚Wasserstein生成对抗网络的引入,构建适宜电磁信号处理的半监督学习框架,实现对无标签信号样本的有效利用。为了验证所提算法的有效性,在RADIOML 2016.04C数据集上进行测试。实验结果表明,该方法在半监督条件下能训练出高效的分类器,获得优异的调制识别结果。     

基于MADM组合赋权的防空武器系统机动能力评估

针对防空武器系统机动能力评估问题不确定多属性决策的特点,提出一种基于MADM组合赋权的武器系统机动能力评估方法。构建了防空武器系统机动能力评估指标体系,给出了指标权重不相容情况下如何寻找并剔除疵点权重的方法。在此基础上,建立了一种基于区间估计解决武器系统机动能力评估问题的数学模型。最后通过实例分析验证,该方法评估结果准确,能有效减小误差,对指挥员科学决策具有一定的参考价值。     

Understanding the ‘failure’ of the Séléka rebellion

This paper examines the downfall of the Séléka rebellion, which staged a coup in the Central African Republic in March 2013. The coup plunged the country into violence and chaos, and there has been an uneasy quest for peace ever since. This article explains why the leader of the rebellion lost control over his troops and was finally pushed by regional actors to leave power. The article concludes that the Séléka rebellion was already fragile and, together with the poor leadership demonstrated by the coalition leader, the rebellion was unable to hold on to power.     

Is the Indian Nuclear Tiger Changing Its Stripes?

Sixteen years after stepping out of the nuclear closet, India's nuclear posture, some of its operational practices, and hardware developments are beginning to mimic those of the original five nuclear weapon states. Several proliferation scholars in the United States contend that India's national security managers are poised to repeat the worst mistakes of the superpowers’ Cold War nuclear competition, with negative consequences for deterrence, crisis, and stability in South Asia and the Asia-Pacific region. This article takes a contrarian view. It dissects the best available data to show why the alarmist view is overstated. It argues that not only are the alarmists’ claims unsupported by evidence, their interpretation of the skeletal and often contradictory data threatens to construct the very threat they prophesize.     

脉冲微分方程边值问题的全局分支与多解性

研究非线性脉冲微分方程边值问题,应用分歧技巧,得到非线性脉冲微分方程边值问题多个解的存在性结果.