融合GMM及SVM的特定音频事件高精度识别方法

针对特定音频事件识别中持续时间特别短的音频事件漏检概率高、识别速度较慢的问题,提出一种融合高斯混合模型（GMM）及支持向量机（SVM）的特定音频事件识别算法. 该方法利用GMM的统计分布描述能力和SVM的推广泛化能力,将GMM和SVM分别识别的结果进行融合处理,以手枪、步枪、机关枪等10类以上枪声为实验数据,无需针对每种枪声生成相应的识别模板,仅需训练生成2个识别模板. 实验结果表明,识别准确率达到92.71%. 该方法模板数量少,不需要多次训练,算法复杂度较低,不仅便于应用而且可大幅提升识别效率.      

Laser intensity induced transparency in atom-molecular transition process

We propose a new transparency mechanism, which is based on photoassociation （PA） laser intensity induced transitional frequency shift for ultracold cesium molecules formed in PA scheme. The PA laser intensity is supposed to change before the atommolecule resonance. Thus, a remarkable transparent effect for PA laser is expected to appear in the vicinity of original resonant transitional line, where the variation of PA laser intensity induces the shift of the excited molecular levels. The mechanism is different from electromagnetically induced transparency effect and interesting for further research on the scattering length for cesium atomic condensate.     

EMG oscillator model-based energy kernel method for characterizing muscle intrinsic property under isometric contraction

This paper presents a new method for estimating the isometric contraction force and the characterization of muscle’s intrinsic property.The method,called the energy kernel method,starts with converting the electromyography(EMG)signal into planar phase portraits,on which the elliptic distribution of the state points is named as the energy kernel,while that formed by the noise signal is called the noise kernel.Based on such stochastic features of the phase portraits,we approximate the EMG signal within a rectangular window as a harmonic oscillator(EMG oscillator).The study establishes the relationship between the energy of control signal(EMG)and that of output signal(force/power),and a characteristic energy is proposed to estimate the muscle force.On the other hand,the natural frequencies of the noise and the EMG signal can be attained with the energy kernel and noise kernel.In this way,the direct signal–noise recognition and separation can be accomplished.The results show that the representativeness of the characteristic energy toward the force is satisfactory,and the method is very robust since it combines the advantages of both RMS and MPF.Moreover,the natural frequency of the EMG oscillator is not governed by the MU firing rate of a specific muscle,indicating that this frequency correlates with the intrinsic property of muscle.The physical meanings of the model provide new insights into the understanding of EMG.     

用于跳频分量搜索的环形拓扑粒子群算法

在分析粒子群局域最优模型和拓扑结构影响的基础上,提出采用环形拓扑的粒子群算法对跳频信号分量进行搜索.通过粒子之间的信息交互程度控制,实现了粒子在分量时频中心的自动聚集,克服了应用匹配追踪和传统多峰粒子群优化算法对跳频信号自适应分解时存在终止条件难以确定和需要先验知识的问题.     

普通群体与近交群体的对比分析

对普通群体与近交群体的有关概念、性质、影响因素、基因型频率的动态趋势以及随机交配率与随机交配指数对基因型频率的影响进行分析.结果表明:普通交配与近交的概念不同;随机交配率与随机交配指数性质不同;普通群体3种基因型频率在世代间的动态逐渐趋于平衡,近交群体3种基因型频率的动态趋于近交系数等于1的状态;随机交配率与基因型频率呈曲线相关,近交系数与基因型频率呈直线相关.     

基于空时分组码与卷积码级联编码的单载波频域均衡技术研究

研究了空时分组码(STBC)与卷积码的级联编码,通过卷积码的纠错能力,进一步降低了系统的误码率,使系统同时获得了满分集增益和较大的编码增益.仿真结果显示,基于级联编码的单载波频域均衡技术的系统性能有较大的改善.     

热源强迫对大气长波调整的可能影响

为了研究热源强迫对大气长波调整的作用,利用考虑热源强迫和涡动耗散的β通道准地转正压位涡方程,通过数值计算的方法,揭示了热源强迫及热源强迫下基流和初始场对长波调整的可能影响。结果表明:除了非线性作用和基流的纬向非均匀性外,热源强迫也是长波调整的机制之一。在有热源强迫时,初始波动和热源强迫在纬向结构上的差异是长波出现调整的关键因子。强迫的纬向非均匀性有利于调整的出现,但调整对强迫的经向非均匀性不敏感。基流较大或较小时,都不利于调整现象的发生;而较大的基流切变能够加速调整的出现。热源强迫相同时,初始波动的振幅越小,流场演变越快,波动出现调整的时间就越早;当振幅取较大值时,则情况相反。     

变频器输入电抗器及直流滤波电容器的设计

在工业生产中,变频器的应用日益广泛。为提高变频器运行的稳定性和可靠性,需为变频器配备合适的电抗器及整流滤波电容器。从电抗器和整流滤波电容器的工作原理入手,阐述了变频调速系统中输入交流电抗器、直流电抗器和整流滤波电容器的作用、适用场合,给出了它们的设计方法,并利用MATLAB软件仿真验证设计的实效性。     

光拍频法测光速实验的改进方法探讨

光拍频法测光速是一种通过测量光拍的速度进而间接测量光速的方法.详细分析光拍频法测光速实验的实验原理和过程,在对实验方法中主要面临的问题和困难进行分析的基础上,忠实原有实验原理,提出了较为科学合理的实验改进意见和构想.     

基于模糊控制分布式变频恒温供暖系统

介绍的是一种运用模糊控制手段实现恒温供暖的自动控制系统,同时又可以根据不同热用户的需求,实现室内温度的手动控制。该系统应用温度传感器采集室内温度与设定温度之间的差值,作为输入信号,通过PLC控制变频泵转速,同时该系统还可以通过手动调节变频泵转速,根据热用户的需求手动调节室内温度。