失去润滑条件下弧齿锥齿轮传动系统瞬态温度场Simulink仿真分析

根据传热学理论和热网络法,以某型直升机尾减速器弧齿锥齿轮传动系统为研究对象,建立了其温度场Simulink仿真计算模型。基于该模型,计算获得该传动系统正常润滑条件下的稳态温度场,并以它作为初始条件计算分析该传动系统失去润滑条件下的瞬态温度场,为预测该弧齿锥齿轮传动系统在失去润滑条件下的干运转生存能力提供理论依据。     

弹载惯性测量系统抗高过载技术

在现代高技术条件下的局部战争中,为了提高火炮的射程、打击精度和反应速度,发展制导炮弹系统就成为必然的选择.弹体姿态测量系统是制导系统的重要组成部分,解决其在炮弹发射高过载恶劣环境下的生存问题就成为研究的关键之一.提出了主要抗高过载手段,并对弹体姿态测量系统的抗高过载性能进行了Ansys软件仿真、马歇特试验以及实弹飞行试验.最后得到结论,所给出的抗高过载方案在降低高过载对弹体姿态测量系统的影响方面,可以发挥良好的作用.     

防空兵网络化作战指挥控制方式

信息化条件下防空兵作战依托防空兵指挥信息系统,已经将防空兵各个作战要素联结到了一起,初步具备了网络化作战的雏形.而恰当的指挥控制方式是实施高效防空兵网络化作战的关键问题之一.首先剖析了防空兵网络化作战给指挥控制带来的新特点,而后构建了防空兵网络化作战指挥控制方式的概念模型,在此基础上提出了适应防空兵网络化作战的指挥控制方式是自适应指挥控制方式.并研究了防空兵网络化作战实施自适应指挥控制方式的必要性、可行性、内在机理以及实现的途径.     

基于HLA的防区外空面导弹攻防对抗仿真

针对HLA/RTI在接口规范、对象模型模板等关键技术建立分布式仿真平台的复杂性,提出了利用数字武器开发平台进行开发的方法,构建防区外空面导弹攻防对抗系统体系结构,实现了该体系结构联邦成员划分、设计联邦/仿真对象模型表等HLA仿真关键技术,并采用面向对象建模与仿真技术建立了各联邦成员的数学模型.该仿真结果表明,各联邦成员的数学模型与底层支撑环境能够相互分离,仿真模型具有良好的交互性和互操作性,可通过添加或删除联邦成员仿真不同的复杂战场想定,并可作为验证不同算例的仿真平台.     

基于区间数理论的空战目标威胁评估

针对空战目标威胁评估问题,提出了一种新的基于区间数理论的评估方法。在分析了现有的目标威胁评估方法中距离威胁模型存在不足的基础上,提出了改进的距离威胁模型。给出了区间数特征向量法求解威胁指标权重的计算步骤,建立了基于区间数理论的空战目标威胁评估的数学模型。最后给出了仿真算例,仿真结果表明该方法是合理和有效的。     

雷达侦察比幅测向系统干扰技术

重点分析了比幅测向系统的原理,在此基础上提出对其进行"主动反侦察"干扰的方法,推导了受到干扰下比幅测向系统的测量结果公式,讨论了不同条件下的干扰效果,并通过仿真进行验证。     

Component importance for linear consecutive‐ k ‐Out‐of‐ n and m ‐Consecutive‐ k ‐Out‐of‐ n systems with exchangeable components

Measuring the relative importance of components in a mechanical system is useful for various purposes. In this article, we study Birnbaum and Barlow‐Proschan importance measures for two frequently studied system designs: linear consecutive k ‐out‐of‐ n and m ‐consecutive‐ k ‐out‐of‐ n systems. We obtain explicit expressions for the component importance measures for systems consisting of exchangeable components. We illustrate the results for a system whose components have a Lomax type lifetime distribution. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

Nonparametric bayesian lifetime data analysis using dirichlet process lognormal mixture model

We propose a nonparametric Bayesian lifetime data analysis method using the Dirichlet process mixture model with a lognormal kernel. A simulation‐based algorithm that implements the Gibbs sampling is developed to fit the Dirichlet process lognormal mixture (DPLNM) model using rightly censored failure time data. Five examples are used to illustrate the proposed method, and the DPLNM model is compared to the Dirichlet process Weibull mixture (DPWM) model. Results indicate that the DPLNM model is capable of estimating different lifetime distributions. The DPLNM model outperforms the DPWM model in all the examples, and the DPLNM model shows promising potential to be applied to analyze failure time data when an appropriate parametric model for the data cannot be specified. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

Why did Sudan Lose a small war in Southern Sudan?

ABSTRACT

When on the wrong end of an asymmetry in the projection of hard power, weaker sides countenance the grim arithmetic of avoiding direct and massed confrontations. Invariably, insurgents have over the ages tended to employ indirect tactical methods to render their stronger opponents ineffective. Ultimately – interest asymmetry, regime type, asymmetries of strategy, and external intervention – combine in a complex interplay and pattern, to militate against a strong side. In Sudan, these factors interacted throughout the civil wars to produce regional autonomy and finally an independent South Sudan in 2011. Similar strategic logic had confronted many large African states battling insurgencies in Ethiopia, Angola, Nigeria, Zaire, and apartheid-era South Africa. Oftentimes, weakening public resolve has caused these governments to accommodate, capitulate or withdraw even if they try not to blink. Notwithstanding the regime type, it can be concluded that the majority of strong actors are prone to fail in a protracted, asymmetric conflict. Hence, the notion of linking victory in counterinsurgency to the degree of openness (democratic polyarchies); or closeness (totalitarianism) – is still valid but highly contestable in the case of Africa’s large dysfunctional states.     

基于CPU-GPU混合计算平台的RNA二级结构预测算法并行化研究

RNA二级结构预测是生物信息学领域重要的研究方向,基于最小自由能模型的Zuker算法是目前该领域最典型使用最广泛的算法之一。本文基于CPU GPU的混合计算平台实现了对Zuker算法的并行和加速。根据CPU和GPU计算性能的差异,通过合理的任务分配策略,实现二者之间的并行协作计算和处理单元间的负载平衡;针对CPU和GPU的不同硬件特性,对Zuker算法在CPU和GPU上的实现分别采取了不同的并行优化方法,提高了混合加速系统的计算性能。实验结果表明,CPU处理单元在混合系统中承担了14%以上的计算任务,与传统的多核CPU并行方案相比,采用混合并行加速方法可获得15.93的全局加速比;与最优的单纯GPU加速方案相比,可获得16%的性能提升,并且该混合计算方案可用于对其它生物信息学序列分析应用的并行和加速。