基于动网格的翼型设计优化

针对传统基于代理模型的翼型优化的缺陷,提出采用基于动网格的翼型优化;针对基本Hicks-Henne方法后缘不光滑情况进行了改进;采用自编程序实现动网格生成,通过集成商业软件Pointwise和CFD计算软件Fluent完成边界条件生成和流场解算,并实现上述程序和软件间的数据交互和自动化,整个优化流程在iSIGHT平台下执行,优化算例表明基于动网格的翼型优化方法能大幅提高翼型性能,节省大量的重复性操作,增加优化结果的鲁棒性和可信度,是翼型优化中的一种有效方法。     

GETTING BETTER ALL THE TIME

Detect and Deter: Can Countries Verify the Nuclear Test Ban?, by Ola Dahlman, Jenifer Mackby, Svein Mykkeltveit, and Hein Haak. Springer, 2011. 279 pages, $129.     

Building the next nuclear community

This viewpoint takes stock of the changes in the strategic nuclear landscape in recent decades and reflects on its consequences on the policy community. It finds that the number and scope of issues have expanded considerably; they have manifested themselves in many more regions of the world; and they have become deeply politicized and polarized. The consequences have been twofold: the nuclear policy field has seen the development of an increasingly diverse expert community composed of highly specialized functionalists and regionalists, and it has become ever more divided into two entirely separate ideological camps—one that believes in deterrence, the other in disarmament. The stove-piping of expertise and the widening gap between deterrence and disarmament ideologies are immensely problematic because, in different ways, they stand in the way of the emergence of a better and safer nuclear future. Looking ahead, it is critical to “bust the silos of expertise” and to build bridges between the deterrence and disarmament ideological camps. Only such a community-building effort will help solve today’s and tomorrow’s nuclear challenges.     

INCAPACITATING BIOCHEMICAL WEAPONS

Military interest in incapacitating biochemical weapons has grown in recent years as advances in science and technology have appeared to offer the promise of new “non-lethal” weapons useful for a variety of politically and militarily challenging situations. There is, in fact, a long and unfulfilled history of attempts to develop such weapons. It is clear that advances are opening up a range of possibilities for future biological and chemical weapons more generally. The treaties prohibiting biological and chemical weapons make no distinction between lethal and “non-lethal” weapons—all are equally prohibited. Indeed, a sharp and technically meaningful distinction between lethal and “non-lethal” biological and chemical weapons is beyond the capability of science to make. Thus, interest in incapacitating biochemical weapons, and efforts on the part of various states to develop them, pose a significant challenge to the treaty regimes, to the norms against biological and chemical warfare that they embody, and, ultimately, to the essential protections that they provide. Preventing a new generation of biological and chemical weapons from emerging will take concerted efforts and action at the local, national, and international levels.     

基于TCP Veno算法的异构网络边界代理改进机制研究

针对在异构网络环境下无线网络的特点使TCP性能下降的问题,借鉴TCP Veno算法原理,提出基于网络状况评估的拥塞控制的性能增强代理改进工作机制,动态评估当前网络的状况,调整预应答发送窗口的阈值,提高性能增强代理在较大差异网络下的传输控制效能．基于NS-2的网络仿真测试对算法进行了验证,结果显示改进后的工作机制在丢包率较大的异构网络中性能有明显提升．     

分级智能化的武器平台——无人平台体系结构解析

通过对现有机器人体系结构的总结,结合任务需求和当前技术发展水平,构造了一种人机智能紧耦合的无人平台系统结构.该结构分为7层,具有3种导航模式,6种控制方式,能够实现从主从遥控到全自主不同智能层次的无人平台构建,为无人平台的设计提供了工程指导,并为无人平台的应用提供了方向.     

动态液-液旋流分离器油滴运动轨迹模拟

针对动态液-液旋流分离器油、水两相过程,从流体力学基本方程出发,采用雷诺应力模型、QUICK差分格式和SIMPLE算法模拟分析动态液-液旋流分离器内的流场;并以此为基础,采用离散相模型和多相流模型,模拟油、水两相分离过程和油滴运动轨迹.模拟结果表明:油滴粒径决定其在旋流分离器中的运动轨迹、速度及分离特性,大粒径油滴更易于向中心聚集形成油芯,油芯的形状与油滴的大小直接相关;动态液-液旋流分离器的主要分离过程在转筒内完成,油相分离效率随着油滴粒径的增大而提高.     

改进的Fisher准则及其在语音聚类中的应用

针对传统的Fisher准则在聚类分析方面的不足,提出了一种新的修正的Fisher准则。通过重新定义类内方差,得出最大Fisher值与最佳聚类数目的对应关系,从而预测出最佳聚类数目。通过对语音库中语音段落的说话者组成结构进行分析,证明了修正后的Fisher准则能有效地优化聚类分析,并显著提高了说话者组成结构分析结果的精度。应用基于修正后的Fisher准则的LBG聚类算法,能为语音操控系统中无监督的说话人自适应提供更可靠的说话人模板库。     

水面舰艇编队空中威胁扇面角预测模型

针对水面舰艇编队空中威胁扇面角的预测问题,分析了影响空中威胁扇面角大小的主要因素。以具有航路规划能力的远程反舰导弹为对象,从航空兵及远程反舰导弹的作战使用特点和装备性能限制着手,建立了计算威胁扇面角的数学模型。通过仿真分析,得出了主要参数对威胁扇面角的影响规律,为水面舰艇编队对空防御兵力的配置提供了依据。     

基于虚拟飞行仿真的导弹控制系统设计

根据风洞虚拟飞行仿真系统的特点以及试验要求,设计了用于风洞虚拟飞行仿真的模型导弹的俯仰、偏航和滚转通道控制系统。导弹俯仰通道采用了迎角指令控制的三回路闭环控制结构,滚转通道采用了滚转姿态角指令控制的两回路闭环控制结构,而偏航通道采用液压驱动机构来开环控制侧滑角。利用极点配置法设计了俯仰和滚转通道的控制增益。最后通过数字仿真对所设计的控制系统进行了仿真验证。从数字仿真结果可以看出,无论是时域还是频域,所设计的俯仰和滚转通道闭环控制系统均能满足风洞虚拟飞行仿真的要求。