基于两个频点的水声信号盲源分离

实际水声环境中声纳接收到的信号是卷积混合信号。文章中将两个频点盲源分离原理应用到水声信号的盲源分离中，从而有效克服信号频域解卷积过程中的排序和幅度不确定性。仿真实验结果表明该方法对水声卷积混合信号具有良好的分离效果?文章中进一步研究了水声信号在不同信噪比条件下，基于两个频点盲源分离方法的分离性能。     

Control of Variation by Reward Probability.

Two bar-press experiments with rats tested the rule that reducing expectation of reward increases the variation from which reward selects. Experiment 1 used a discrete-trial random-interval schedule, with trials signaled by light or sound. One signal always ended with reward; the other signal ended with reward less often. The 2 signals were randomly mixed. Bar-press duration (how long the bar was held down) varied more during the signal with the lower probability of reward. Experiment 2 closely resembled Experiment 1 but used a random-ratio schedule rather than a random-interval schedule. Again, bar-press duration varied more during the signal with the lower probability of reward. The results support the rule--the first well-controlled comparisons to do so. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A new second-order method for blind signal separation from dynamic mixtures

This paper presents a new approach to separate colored stationary signals mixed by convolutive channels. A cost function is proposed by employing linear constraint to the demixing vectors. The linear constraint is shown to be sufficient for avoiding trivial solution. The minimization of the cost function is performed using the Lagrangian method. Simulation results demonstrate the performance of the algorithm.     

随机信号偶然符合计数率公式的推导

推导了ｍ个随机信号中有ｋ个发生偶然符合的计数率计算公式,并结合实例说明了其应用。     

人工蜂群算法优化支持向量机的分类研究

为了提高支持向量机分类准确率,采用人工蜂群算法对支持向量机参数进行优化,并将该优化方法应用于小麦完好粒、霉变粒和发芽粒三类麦粒的识别。使用小波变换分解信号能量作为特征向量,以分类错误率的倒数作为适应度函数,利用人工蜂群算法对支持向量机的惩罚因子和核函数宽度参数进行优化,优化SVM方法对小麦完好粒、霉变粒和发芽粒的分类正确率达到86%以上。实验结果表明,该研究有较强的实用价值,为SVM性能优化提供了一种新的方法。     

Auditory signals in military aircraft: ergonomics principles versus practice

The complete ensembles of auditory signals in selected USAF aircraft (the F-4D, F-15, two models of the F-16, the C-5, and the C-141) are described and evaluated. Human factors research related to the design of speech and non-speech auditory signals is reviewed. Major findings are: that auditory signals are not well standardised among the aircraft, even between those with similar combat roles; that a relatively large number of non-speech auditory signals are used, which may make it difficult for the aircrew to recall the meanings of all the signals; that some non-speech signals are sufficiently similar that they may be confused, particularly in high workload and stressful conditions; and that the criticality of the warnings is not reliably indicated by any characteristic of the signals. Four problem areas requiring further research are discussed: reduction of signal loudness, enhancement of the distinctiveness and masking resistance of non-speech signals, effects of concurrent warning signals on aircrew performance, and additional uses of auditory information.     

一种易于电路实现的鲁棒盲神经网络波束形成器

绝大多数通讯信号都具有周期平稳信号特性。利用信号的周期平稳特性可以进行真正的盲自适应波束形成,因而受到了广泛关注。鲁棒ＣＡＢ（Ｒ－ＣＡＢ）算法就是其中的一种,但其中涉及矩阵求逆,运算量很大。波束形成属于多维信号处理问题,阵列中阵元数的增加导致运算量成几何级数增加。文中提出了一种盲神经网络波束形成算法。由于神经网络具有网状计算结构的特点,故该方法不仅避免了矩阵求逆运算,同时更便于实时实现。该方法还利用对角加载技术,从而加快了收敛速度,保证了算法的鲁棒性。仿真实验表明其性能优越,易于电路实现     

采用神经网络控制的超精密平面定位

设计了一种基于激光莫尔信号的超精密平面定位装置,该装置可实现高精度位置检测及X-Y-θ 三自由度的全自动精密平面定位。激光莫尔信号传感器为相位相差 180°的两组衍射光栅,构成差动光栅技术,可有效提高位置检测信号灵敏度及定位精度。针对系统存在非线性,精确控制模型难以建立的缺陷,提出基于 RBF 神经网络的精密定位控制,其控制响应快、稳定性好、鲁棒性强,可有效改善控制质量,提高定位速度。实验结果表明,基于激光莫尔信号的精密定位装置可获得亚微米级的平面定位精度。     

高血压患者脉博信号的采集与频谱分析

根据人体脉博信号的特点,提出了一种对脉搏声信号进行检测和数据采集的方法。讨论了脉搏声信号采集和处理过程中各参数之间的关系及应选取的指标,介绍了脉搏信号的一种频域分析方法——功率谱分析,获得了两种脉搏信号的功率谱图。取检测对象１０８例,其中通过对６５例高血压患者、４３例健康人作为对照组的脉象信号的功率谱计算,发现高血压患者脉搏功率谱高频部分的能量分布较健康人发生了明显的变化,并从人体生理病理学的角度分析了变化的可能原因。得出了对高血压疾病的临床诊断有参考价值的结论     

基于局部投影和提升小波的混沌信号降噪

根据信号和噪声的不同特性,提出了一种基于局部投影和提升小波的混沌信号降噪方法。该方法利用提升小波变换得到实际混沌信号的近似系数,对其进行相空间重构,与实际混沌信号的重构相空间进行比较,来选取局部投影的邻域,在局部邻域内进行奇异谱分析,利用代表吸引子的主分量来重构混沌信号。通过对Lorenz模型和月太阳黑子进行仿真分析,证实了提出方法对混沌信号降噪的有效性。