星际探测太阳帆行星和太阳借力轨道全局优化

以太阳帆在20年内飞行至距离太阳200 AU以远进行星际探测为目标,研究太阳帆通过行星借力和太阳借力的轨道全局优化问题。建立太阳帆时间最优转移轨道数学模型,分析行星借力和太阳借力的约束条件,并用这些约束条件构造目标函数,从而将轨道优化的四点边值问题转化为求解无约束条件下的多变量优化问题。通过选取合理的约束权重,采用遗传算法获得大范围的粗略解,代入到序列二次规划算法中获得高精度解。仿真结果表明,虽然太阳帆通过太阳借力已获得相当大的加速度,但加上木星借力仍然可以节省相当多的飞行时间。提出的轨道优化思路,可以为太阳系逃逸任务轨道初步设计提供参考。     

基于熵权决策的灭火救援方案优选方法

针对灭火救援方案优选中属性信息的模糊特性,提出了一种基于熵权决策的多属性灭火救援方案优选方法。该方法模型充分挖掘了待选方案的固有信息,采用熵权和专家评判相结合的方式,确定了一个综合考虑主客观因素的评价权重,进而通过确定熵权系数对待选方案进行排序优选,避免了决策者的主观偏好和意向,使决策更加科学化。实例研究表明:该方法模型的决策结果相对比较合理、客观、可靠,具有较强的实用价值,可为消防指挥员进行指挥决策提供参考,同时也为模糊多属性决策问题提供了一条新的解决途径。     

创造观的哲学认识论基础

人类认识的本质是一种观念的建构,它包括反映性认识和价值性认识。相应地,创造活动的本质就是改变已有的观念建构,它包括反映性创造和价值性创造。     

Mimetic and normative isomorphism in the establishment and maintenance of independent air forces

Why do countries have air forces? Organizational alternatives, such as maintaining separate air arms for the army and navy, have become quite rare. The conventional narrative advanced by advocates of independent air forces stress that the primacy of airpower in modern warfare mandates centralized control of most military aviation. In this view, political–military uncertainty has driven mimetic isomorphism – pressure on national governments to organize as others organize so as to fight or deter war just as effectively. However, working from a set of 56 countries that were politically independent within a few years of the establishment of the first ever independent air force (the Royal Air Force) in 1918, and continuing through nearly the present, there is no clear pattern of external military pressure prompting this particular reorganization. Rather, from anecdotal evidence, the cause has more likely been normative isomorphism – a professional craving to look as others look to foster political or personal legitimacy. For whatever reason, though, choices of structures tend to lead to specific choices of policies. Thus, the result suggests that defense ministries looking for more effective or less costly organizational schemas may reasonably consider alternatives to the tripartite army–navy–air force structure.     

基于感兴趣区域及LOD模型的图像压缩算法研究

感兴趣区域ROI(Region of Interesting)模型和层次细节LOD(Level of detail)模型是静止图像压缩及网络传输技术中两个重要模型.采用基于认知心理学的图像感兴趣区域提取模型,通过显著图法自动地得到与人眼视觉较吻合的ROI区域,并使ROI区域获得比背景区域更好的图像效果.同时通过将图像网格化,并在图像网格上进行B样条细分小波变换,实现了图像在不同分辨率下LOD压缩算法.     

直升机低空突防中威胁因素的作用距离

分析了武装直升机在实施低空突防时的主要威胁来源.通过对雷达探测原理和低空条件下雷达受到的限制分析及其威胁作用距离计算,阐明了低空探测时常规雷达的不足,介绍了目前新的低空电磁探测方式;通过红外探测、噪声探测的原理和特点研究,表明了这两种方式在直升机低空突防威胁中的重要性,计算了其作用距离;讨论了上述三种方式作用距离,计算结果可以为航迹规划中参考轨迹和安全走廊的确定提供了参考.     

Estimating the probability of a diffusing target encountering a stationary sensor

The problem addressed is that of estimating the probability of a moving particle (called the target) avoiding detection by a stationary sensor to time t. The target follows a diffusion path and is constrained to remain within a square region R. The detecting sensor is fixed at the center of A. Two expressions for this probability are given. The first results from an approximation to the exact solution of the diffusion equation and the second from experimentation with a Monte Carlo simulation of the diffusion process.     

导弹发射车抗毁伤能力分析与评估技术研究综述

现代战争日趋透明给导弹发射车战场生存带来了严峻挑战。围绕发射车的抗毁伤能力分析和评估技术,分析了发射车面临的毁伤威胁和毁伤作用机理,从抗毁伤能力评估应用的角度阐述了冲击波、动能、热和电磁四种毁伤类型的研究现状,提出了不同毁伤类型在抗毁伤能力分析和评估中的应用方向;基于易损性分析空间理论,总结了装备易损性分析的发展历程,认为从物理空间到性能空间的逻辑传递关系是现阶段发射车易损性分析的核心所在,并从物理判据、性能判据和分级标准介绍了易损性判据的研究动态,提出了发射车易损性判据的关键;明确阐述了发射车抗毁伤能力的研究概念和分析方法面临的主要问题,研究结论可以为导弹发射车抗毁伤能力分析和评估相关研究提供参考。     

掠海地效翼船——21世纪的新型海上高速运输运载工具

介绍了一种新型海上高速运载工具——地效翼船的过去和现状,特别是其在俄罗斯的发展.分析了地效翼船的性能及技术特点,并讨论了它的商业用途和军事用途.     

Learning and costs in airframe production: A multiple-output production function approach

This article examines the influence of both production rate and learning on airframe program costs. A dynamic multiple-output production model is developed and is used to observe the cost impact of changes in production rate and learning. Several simulations are performed to demonstrate the sensitivity of the optimal time path of cost to changes in the model parameters. The model is applied by estimating parameters from the F102 airframe program.