The application of evolutionary algorithm in determining T wave-end

There have been several methods for determining T wave-end. But none of them can overcome the difficulty from multiformity of ECG signal pattern. In this paper, a method for determining T wave-end using evolutionary algorithm (EA) is proposed. In this way, first, every characteristic parameter related to T wave-end is encoded to a string of codes, and adaptation function is constructed with the string of codes. Then choose the individual according to the adaptation function value and do genetic operation (reproduction, crossover and mutation), so as to produce offspring with more adaptation function value. Because of EA's autoadaptation and autoorganization character, it can trace ECG signal type and find the T wave-end automatically. Experiment results show that the error ratio of recognizing T wave-en'd using this method is much smaller than that using existing method.     

EA4T钢冷却过程中脉冲电流对组织与性能的影响

针对EA4T钢车轴淬火过程中心部会析出大量大尺寸先共析铁素体的问题,采用脉冲电流辅助加热方法,研究冷却过程中脉冲电流与先共析铁素体析出的关系。EA4T钢试样加热至900℃保温20min后,以25℃/min冷速冷却,并在冷却过程中通入一定参数的脉冲电流。结果表明,由于脉冲电流辅助加热的热效应,推迟了相变过程中先共析铁素体在奥氏体晶界处的析出。与未通脉冲电流的试样相比,先共析铁素体的含量降低,尺寸减小,试样的强度、伸长率及冲击值有所提高。     

Mobile RFID的安全和隐私问题研究

射频识别技术被广泛应用于物体的自动识别,广泛地部署射频识别的标签会给用户的隐私带来新的安全威胁。目前,射频识别出现一种融合的趋势,阅读器被集成到移动电话中。移动射频识别主要应用于普通终端用户,用户的安全和隐私是最优考虑的问题。论文描述了移动RFID的应用场景和安全及隐私威胁,重点描述了移动环境下特殊的安全和隐私危险及解决移动RFID安全和隐私问题的安全体系构架方案。     

The Performance of the Adaptive Aggregation Mechanism (AAM) Under Mixed Traffic Loads

The adaptive packet aggregation algorithm (AAM) has been shown to have a superior performance over the first-in first-out (FIFO) algorithm in terms of the throughput and delay (Deng and Davis in International conference on wireless communications and signal processing 2013 (WCSP2013), Hangzhou, China, pp 449–504, 2013; 20th IEEE symposium on communications and vehicular technology in the Benelux 2013 (IEEE SCVT 2013), Namur, 2013). In this paper, we will show that when compared with the FIFO and smallest-size first-served algorithms, the AAM algorithm has the best performances in terms of the trade-off between the overhead saving and the average delay under mixed traffic loads in wireless LANs. The simulation results show that the AAM algorithm produces the largest average aggregate packet size.     

变参量Wiggler FEL的三维非线性理论

本文建立了变参量Wiggler自由电子激光放大器的三维自洽非线性理论。考虑电磁波、电子注和Wiggler场三者均在三维空间中变化,忽略电子注的自身场和空间电荷效应,导出了带有变参量双绕螺旋Wiggler场和轴向导引磁场的矩形波导,轴对称电子注自由电子激光器的非线性互作用微分方程组。数值模拟表明:在适当位置逐渐减小Wiggler场的幅值或周期均能有效地提高电子注的能量转换效率。     

铸造铝合金(ZL109)激光表面处理

采用功率为2kW级CO_2连续可调式横流激光光源,对不同涂层的ZL109试样表面进行了激光熔凝的实验研究。     

光学颗粒计数测量技术的理论模型

光学颗粒计数测量技术,以激光器作光源利用高灵敏度光电探测器件逐个测量被测颗粒的散射光,从而获得微米级颗粒的尺寸和数量参数。该技术对微电子、医药、机械工程、石没等许多工业领域具有重要意义。本文拟对该技术所需的理论基础,从物理和数学的角度较全面地加以阐述,从而建立超一套实用化的理论模型。     

激光对牙齿作用的实验研究

本文介绍了牙齿的吸收光谱及不同种类的激光对牙齿的作用。结果表明,较大能量密度的连续波激光,可瞬时气化牙釉质、牙本质等,与此同时还引起牙齿未作用区的龟裂,实验测得取大无龟裂能量密度约为１００Ｊ／ｃｍ＾２,而脉冲激光作用界限明晰,且周边无龟裂。     

新颖的功率半导体器件RSD及其应用

反向开通可控硅二极管是一种近年来发展起来的新型半导体功率开关器件,具有很强的导流能力。在大功率固态化电源应用中,具有很大的优势。本文分析了这种器件的构造及工作机理,并说明其应用。     

DXC 1/0数字交叉连接系统的设计

本文论述了ＤＸＣ１／０数字交叉连接的设计原则,系统结构及主要功能,重点了数字交叉网络的设计。