数字式稳态频率特性测试仪设计

通用频率特性测试仪在使用中存在两个问题：一是与计算机接口困难,二是稳态测试和暂态测试相互影响导致测试结果不准确。在微处理器控制下,数字分频器和锁相环提供精确的点频激励源,程控数据采集电路处理响应信号。根据这一原理构成的数字式稳态频率特性测试仪较好地解决了上述问题。     

基于DCT的帧内视频编码器的缓存控制技术

提出一种基于ＤＣＴ的帧内视频编码器的缓存控制技术。它根据视频图像各种子块的比例及其相应的Ｒ－Ｑ曲线确定量化因子，通过再编码，调整子块Ｒ－Ｑ曲线的拟合参数使其自适应视频图像的场景变化。同时本文提出了一个简单有效的图像子块分类方法，分类结果基本上与根据编码子块所需比特数分类子块的结果相一致。此法用于缓存控制的额外计算量小，并能扩展应用于Ｈ．２６１、ＭＰＥＧ等视频编码标准中。模拟结果表明，此法在视频序列的场景发生变化时，再编码次数少，输出码率恒定。     

Research on fuze microswitch based on corona discharge effect

Abnormal voltages such as electrostatic, constant current, and strong electromagnetic signals can erro-neously trigger operation of MEMS pyrotechnics and control systems in a fuze, which may result in casualties. This study designs a solid-state micro-scale switch by combining the corona gas discharge theory of asymmetric electric fields and Peek's Law. The MEMS switch can be transferred from "off" to"on" through the gas breakdown between the corona electrodes. In the model, one of the two electrodes is spherical and the other flat, so a non-uniform electric field is formed around the electrodes. The theoretical work is as follows. First, the relation among the radius of curvature of the spherical electrode, the discharge gap, and the air breakdown voltage is obtained; to meet the low voltage (30-60 V) required to drive the MEMS switch, the radius of curvature of the spherical electrode needs to be 10-50 μm and the discharge gap between the two electrodes needs to be 9-11 μm. Second, the optimal ratio ε is introduced to parameterize the model. Finally, the corona discharge structural parameters are determined by comparing the theoretical and electric field simulation results. The switch is then fabricated via MEMS processing. A hardware test platform is built and the performing chip tested. It is found that when the electrode gap is 9 μm, the electrostatic voltage is at least 37.3 V, with an error of 2.6% between the actual and theoretical air breakdown voltages. When the electrode gap is 11 μm, the electrostatic voltage is at least 42.3 V, with an error of 10.5% between the actual and theoretical air breakdown voltages. Both cases meet the design requirements.     

两种基于 DCT 变换的数字水印算法分析

本文介绍了多媒体数字水印的概念，对当前的技术现状进行了简单的综述，重点研究了两种ＤＣＴ 域上的数字水印算法的检测过程，在此基础上对两者的性能和特点进行了分析，并且进行了实验仿真验证。     

某型导弹智能维修训练系统设计

智能维修训练系统是智能教学训练系统在故障维修领域的应用。以某型导弹武器系统为对象阐述了智能维修训练系统的设计和实现,研究了该系统的总体结构以及知识表示、学生模型、推理机制、仿真环境的实现方法。     

子波域中图象数据的矢量量化

介绍了子波变换的基本理论及特点,并用它对图象进行三层分解。矢量量化优于标量量化。它已成功地应用于图象的数据压缩。文中应用失显量化法量化图象于波域数据,取得较满意的压缩效果。     

某导弹武器系统故障诊断专家系统研究

研究了某导弹武器系统故障诊断专家系统的知识表示、推理机制、知识获取等功能模块。     

The nexus between military expenditures and economic growth in the BRICS and the US: an empirical note

This empirical note re-examines the causal linkages between military expenditures and economic growth for the BRICS countries (Brazil, Russia, India, China, and South Africa) and that for the USA during the period 1988–2012. Results of Granger causality tests show that military expenditures influence economic growth in the USA, economic growth influences military expenditures in both Brazil and India, a feedback between military expenditures and economic growth in Russia, and no causal relation exists between military expenditures and economic growth in China and South Africa. The findings of this study can provide important policy implications for the BRICS countries and also for the USA.