利用非线性自适应技术检测微弱的瞬时信号

本文根据局部流形理论,提出了一类非线性自适应预测滤波模型。仿真结果显示,本文提出的自适应预测滤波模型具有很强的非线性近似能力,可以检测淹没在超混沌或杂波环境中的瞬时信号。     

SAR图像组合分割算法

由于存在乘性斑点噪声的影响,给SAR图像分割造成很大困难,本文研究利用最大似然区域增长分割算法,提出区域增长前引入自适应边缘检测,图像分割性能获得较大提高.介绍了我们研究的分割性能优异的模拟退火分割算法,提出了分割性能接近模拟退火并且在SAR图像分割中比较实用的模拟退火和最大似然混合分割算法,并给出了这些分割算法的分割性能比较,以及在实际分割SAR图像时应当如何选择分割算法.     

Layered Video and Differentiated Coding for Adaptive QoS in Mixed Wired-Satellite Networks

Mobile networks are becoming nothing but a way to allow ubiquitous access to multimedia services. To allow efficient use of resources, new systems provide flexible bandwidth and different error protection techniques to match channel behavior. As the backbone network is increasingly becoming based on packet techniques and in particular on IP and related transport protocols, end to end service quality must be analyzed considering both the fixed and the mobile part. Source scalability may help in coping with a mixed and heterogeneous environment. In this work we present some results of a transmission chain comprising a scalable MPEG-2 coder, an IP network and a radio access exploiting the availability of satellites. It is shown that for a given target rate, differentiated coding can be exploited to achieve decodability and good quality at a channel SNR much lower that single layer streams. This revised version was published online in July 2006 with corrections to the Cover Date.     

自适应RBF神经网络在CDMA移动通信上行链路功率控制中的应用研究

提出了一种自适应RBF神经网络功率控制方案。详细研究了该网络在DS-CDMA通信中，进行上行链路闭环功率控制(基于信扰比(SIR))的应用理论，给出了该网络参数的计算方法。最后用计算机仿真法模拟出该控制器的运行性能。结果表明基于SIR的自适应RBF神经网络功率控制器能自适应地调整移动台的发射功率，使基站接收信号的信扰比始终非常接近于一个常数，且有比定步长功率控制更小的SIR跟踪误差，从而可以降低接收信号的中断概率、提高信道容量。     

设计IIR数字滤波器的遗传优化算法

提出了ＩＩＲ数字滤波器设计的遗传优化法。这是一种模拟自然遗传和达尔文进化理论的随机并行优化算法。首先，详细描述了遗传算法并给出了计算步骤，然后将遗传算法用于ＩＩＲ数字滤波器的优化设计，最后给出了模拟计算结果。     

Comparisons of pharynx, source, formant, and pressure characteristics in operatic and musical theatre singing

Belting, a vocal technique typically cultivated in musical theatre singing, differs timbrally from operatic singing in many interesting respects. The underlying phonatory differences have not been previously investigated in detail. Yet, belting is frequently associated with disturbances of voice function. Articulatory and phonatory characteristics are investigated in a female subject who is a professional singer (co-author JL) trained in both the operatic and belting styles and in an intermediate vocal technique (“mixed”). This article presents data obtained from this subject by video-fiberoptic observation of the pharynx, inverse filtering of airflow, and measurement of subglottal pressure. The results reveal that belting was characterized by very high subglottal pressures and sound levels, and apparently also by a comparatively high degree of glottal adduction. Comparisons with other investigations of related aspects of belting and operatic singing support the assumption that the data obtained from our subject are representative for these vocal techniques.     

Low-Power Adaptive Biased Integrated Amplifiers

In this paper the author will present the working principle and the applications of a novel adaptive biasing topology, designed to decrease the stand-by power dissipation without affecting the transient performance of low-power amplifiers. The proposed circuit, whose principle and circuit topology can be implemented both in CMOS and in bipolar standard technologies, gives a biasing current whose value depends on the applied input differential voltage and can be set according to the requested transient performance constraints. The adaptive architecture can be utilized in the design of high-efficient low-power operational amplifiers, for the biasing of both the input stage (where the input source current is dynamically increased) and the output stage (where the output current can be controlled and limited). These amplifiers show a very good behaviour, evaluated in terms of two efficiency factors, if compared with those of other adaptive solutions and class-AB topologies, proposed in the literature. Simulation results and also measurements on a chip prototype, fabricated in a standard CMOS technology, are finally presented.     

电子直线加速器磁控管频率稳定的自适应线性神经元方法

 电子直线加速器电子束能量的稳定与否取决于功率源工作频率的稳定性,磁控管在短时间内的散谱和轻微跳谱造成稳频系统的控制精度下降,最后电子束的扫描均匀度下降。引入自适应线性神经元方法(ADALINE)和噪声对消技术以消除对工作频率长期稳定性的影响,从而保证了电子束的扫描均匀度。     

红外图像序列小目标检测预处理技术

文中就如何复杂背景条件下低信噪比的小目标检测概率问题展开了讨论，提出了用空间高通滤的方法改善图像质量，达以抑制背景噪声，增强小目标的目的，并交坑通滤波和中值滤波做了一个简单的比较，随后采用分层投票表决法对目标进行检测，取得了良好效果。     

在线滤波技术在光纤马赫-德尔交叉复用器中的应用

为构造出与理想梯形滤波器接近的滤波形状，在单级光纤马赫-德尔交叉复用器的基础上，引入在线滤波技术；通过增加干涉级数和调整2对干涉臂的干涉长度和耦合器的耦合比，实现了逼近宽带陡沿的滤波输出。通过与梯形滤波器傅里叶展开式的比较，计算得到了器件的最佳参数，器件的滤波性能以及温度稳定性相对于单级结构得到了明显提高。根据理论计算，成功制作出通道间隔为50GHz的样品器件。其输出为-0.5dB，带宽大于0.185nm，相邻通道隔离度大于30dB，满足了DWDM系统指标要求。