舱内气压的控制方法

本文通过可控性分析和可观察性分析指出,现有的舱压控制系统不是状态完全可控制的,因而不是好的方法。本文提出一种新的控制测量方案,它的控制系统是压力变化速率控制系统,它的测量系统是压力测量系统。这个新的方案是状态完全可控和状态完全可观察的,因而是一个好的方案。     

China’s Aviation Industry: a Global Partnership Strategy

This article discusses one of the main strategies which China has implemented to develop its competency in the aviation field. It is strategic for China to boost its aviation industry via international cooperation and several models of involvement into the global aviation value chain with leading aviation industries. As it is depicted as a strategy here, it is not necessary to say that a formal strong national strategy in encouraging exists. Actually, it is clearly a way China’s aero industry takes to develop its competency and business at the context it encounters. From an observer’s perspective, it is indeed a critical strategy. This article describes this strategy via the context, policies, program cases, as well as the evolution of the cooperation models in order to synthesize the strategy.     

红外焦平面阵列相对光谱响应测试系统

由电子41所研制的红外焦平面阵列相对光谱响应测试系统采用单光路标准替代法进行测量，系统组成灵活并可扩展，配合自行研制的图形发生器，偏置，时钟驱动、数据采集子系统，可以满足不同被测器件的需要。     

一种基于先验知识的3D位姿参数识别方法

计算机视觉中用单幅照片来识别三维物体的六个自由度是非常困难的，但是，在知道一些先验知识的情况下，可以对物体的六个自由度进行识别。本文提出一种基于先验知识的三维位举参数识别的方法，使用物体上不共线的三个特征点及目标点来确定物体的位置和姿态，给出了六个参数的解析表达式，在实时处理中可以得到好的效果。     

防代理技术在校园网中的应用

本文分析了某大学校园网网络现状以及网络存在的问题,针对用户大量代理上网导致网速慢的问题,进行了深入的分析,提出了利用限制用户连接数的方法解决代理问题的方案,介绍了防代理技术的原理和具体实施步骤,并对该方案的落实情况和应用效果进行了比较分析,为网络代理问题的解决提供了一个新的思路。     

Integrated Planning and Execution for Autonomous Spacecraft

An autonomous spacecraft must balance long-term and short-term considerations. It must perform purposeful activities that ensure long-term science and engineering goals are achieved and ensure that it maintains positive resource margins. This requires planning in advance to avoid a series of shortsighted decisions that can lead to failure. However, it must also respond in a timely fashion to a somewhat dynamic and unpredictable environment. Thus, in terms of high-level, goal-oriented activity, spacecraft plans must often be modified due to fortuitous events such as early completion of observations and setbacks such as failure to acquire a guidestar for a science observation. This describes an integrated planning and execution architecture that supports continuous modification and updating of a current working plan in light of a changing operating context.     

TUBSAT-N,an ultra low cost global communication nanosatellite system

In the framework of the research project TUBSAT-N (Technical University of Berlin SATellite-Nano) it has been demonstrated that it is possible to achieve ultra low cost space access very quickly. TUBSAT-N and TUBSAT-N1 were launched as a satellite cluster in July 1998 with a convertible Russian military SS-23 SHTIL Rocket from a submarine. This project should prove that nanosatellite technology can be a good solution for a commercial ultra-low cost project.     

Viral attack to Internet banking applications

The PC Bank may be the most timesaving banking innovation since the ATM (Automatic Teller Machine). However, it also brings new possibilities for thieves. This is mainly because we have not completely solved the growing problem of computer viruses and Trojans that can act on our computers against our will. Several methods are used against them, although none can be considered 100% effective. Even more, most personal computers have little or no virus protection, so they are very easy to attack. This can become a problem as nearly all PC banking systems rely on authentication with identification passwords. This system is vulnerable and we will show that it does not provide enough protection for the users that want to make transfer operations from their accounts     

基于飞行品质的飞机控制增稳系统参数估计

提出了一种控制增稳系统参数的设计方法,即利用低阶等效系统和飞行品质边界,通过搜索算法确定满足对应飞行品质的参数集合,再利用多种飞行品质确定的参数集合的交集和数据的插值算法,确定控制增稳系统的控制律参数。通过纵向增稳系统设计仿真表明,所提方法简化了传统设计方法通过性能指标反复选择参数和验证系统飞行品质的过程,为控制增稳系统的设计提供一种简单有效的方法。     

树形结构SVMs多类分类的研究

介绍了SVM方法原理,为了将SVM在解决两类分类问题中的优越性推广至解决多类分类问题,分析构建树方法与SVM结合运用来提高SVM在进行多类分类时的训练效率的方法, 然后构造文本自动分类,实验说明该方法有较高的训练效率,并且所需的训练样本量大大降低。     

ARINC659总线协议同步机制的研究与实现

总线的同步保证了设计能够正常工作,因此在通信系统中有着极其重要的地位。描述了ARINC659（Aeronautical Radio Incorporated,航空无线电组成公司的）总线规范,分析了该协议采用的TDPA（Table Driven Proportional Access,表驱动均衡访问）通信机制,给出了符合协议规范的同步机制设计并得出了相应的设计结果。主要研究ARINC659协议同步机制,希望能对研究总线同步的同行有所帮助,对ARINC659总线的描述也有助于同仁对ARINC航空总线的研究。     

Fluctuation Loss and Diversity Gain for In?Phase Systems with Post?Detection Integration

This paper presents a simple method for determining the losses resulting from detecting only the in-phase component of the complex signal vector returned from a Rayleigh-distributed target. A simple rule is given in terms of the fluctuation loss and integration gain of square-law-detected pulses. The integration improvement for the in-phase channel is given for both slow and fast fluctuating Rayleigh targets. The loss associated with failure to use the quadrature signal component is basic in that it accounts for only one Gaussian sample and, therefore, one degree of freedom. The loss incurred with one square-law-detected return as normally implemented in radar receivers represents two degrees of freedom. It is well known that the system performance improves, approaching that for the constant target, with increasing degrees of freedom of the received data. This paper is an extension of earlier work in that it relates previously computed data to a simple rule.     

Detection threshold selection for tracking performance optimization

A technique for the evaluation of the track loss probability and the estimation error during track maintenance in clutter has been developed recently by the authors. This work overcomes the limitation of an earlier technique that does not handle the transient process of tracking divergence. Track loss, being a “runaway” phenomenon, clearly requires transient evaluation capability. The new technique provides, without the need for expensive Monte Carlo simulations, the probability that a hack is maintained in the presence of all sources of uncertainty encountered In a tracking process. This technique is of a hybrid nature; it involves explicit probabilistic accounting of both the continuous and the discrete uncertainties. Here it is demonstrated how this technique can be used for the selection of the detection threshold to optimize the overall performance of a detection-trading system     

Radar Waveform Selection-A Simplified Approach

Radar measurement and resolution performance, as well as target detection in clutter, depend largely on the transmitted waveform. This explains the sizable effort that has gone into studies of radar waveforms, including attempts at the synthesis of optimum waveforms. This paper shows that, despite the unlimited variety of radar signals, waveform selection is a straightforward process. There are only four classes of waveforms, each with distinct resolution properties. When the target environment is analyzed for a particular application, it is rather evident which of these classes will fit the situation best. Choice of the specific waveform within the selected class then is merely a matter of practical implementation. Although the facts used in developing the unified theory of this paper are not new, it is demonstrated that these facts can be combined into an extremely simple theory of waveform design. Much of today's work is guided by past approaches to a particular problem, and when a design is completed there may be a question as to how close to the optimum it is. The theory presented here permits a systematic approach to waveform selection, with the important benefit that the designer knows exactly where and how much he may have deviated from the best design, and why this was done.     

一种新的最小维修优化数学模型的建立

论述了可靠性模型在维修决策中的作用。在传统维修模型维修费用的基础上 ,建立了一般及考虑维修时间的新的最小维修优化模型。该模型是对传统的维修模型的扩充和发展 ,此法对维修性理论的发展和维修实践活动有一定的参考作用。     

基于多普勒变化率的机载单站短基线测距方法

已有的分析表明,通过对多普勒频移变化率方程的近似处理即能实现仅基于多普勒频移测量的机载单站测距。在此基础上,本文进一步研究了在机载单站探测平台上,利用一个短基线二单元阵列实现实时测算载机与目标间径向距离的方法,其中所需解决的最主要问题是对时差值的测算。研究表明,只需将路程差看成是基线长度的投影,并等效成是在径向方向上载机以径向速度移动所产生的,即能获得可使测距结果和理论值相吻合的时差值。     

关于湍流问题的注记

指出N-S方程是研究湍流所遵循的基本方程, Reynolds方程反映了在湍流中随机性与确定性共存;Burgers-KdV方程与湍流机理无关, 不能作为湍流研究的“新方程”      

TiO2-有机硅热控涂层对空间聚合材料的防护

在原子氧 (AO)地面模拟设备中对空间材料Kapton及TiO2 有机硅热控涂层进行原子氧剥蚀效应试验。用LAMBDA 9分光度计、光电子能谱 (XPS)、红外光谱 (FTIR)和扫描电镜 (SEM )研究了原子氧 (AO)对Kapton侵蚀机理及对其表面涂覆的TiO2 有机硅热控涂层的防护作用进行了表征。AO对Kapton表现了较严重的侵蚀作用 ,而所施用的TiO2 有机硅热控涂层的表面形貌则变化甚少 ,实验表明 ,该涂层对AO辐照有较强的防护效果、较好的空间稳定性和热控性能。     

基于DSP和准同步算法的谐波监视控制器的研制

设计了一种多功能谐波监视控制器,该控制器基于DSP芯片TMS320C6713进行软硬件设计,采样运用准同步采样法.该控制器具有根据现场谐波污染状况进行滤波器投切功能,同时还可以通过监视器对现场移动物体侵入进行报警,具有良好的实际应用价值.     

Integrated track maintenance for the PMHT via the hysteresis model

Unlike other tracking algorithms the probabilistic multi-hypothesis tracker (PMHT) assumes that the true source of each measurement is an independent realisation of a random process. Given knowledge of the prior probability of this assignment variable, data association is performed independently for each measurement. When the assignment prior is unknown, it can be estimated provided that it is either time independent, or fixed over the batch. This paper presents a new extension of the PMHT, which incorporates a randomly evolving Bayesian hyperparameter for the assignment process. This extension is referred to as the PMHT with hysteresis. The state of the hyperparameter reflects each model's contribution to the mixture, and thus can be used to quantify the significance of mixture components. The paper demonstrates how this can be used as a method for automated track maintenance in clutter. The performance benefit gained over the standard PMHT is demonstrated using simulations and real sensor data