A Novel Stochastic Blind Adaptive Muitiuser Detector for CDMA Systems for CDMA Systems~

Blind adaptive multiuser detector has become a research hotspot in recent years due to a num-ber of advantages, but many blind adaptive algorithms involve low convergence rate. This paper presents a novel stochastic blind adaptive multiuser detector without requiring training sequences,which needs only two system parameters: the signature sequence of the desired user i, si and the variance of the additive white Gauasian noise (AWGN) ,σ^2. Simulation results show that by rea-sonably choosing time varying step size, the proposed detector can not only improve the conver-gence rate, but also reduce the limiting NSE (Normalized Squared Error) values, so it can effec-tively increase the performance of the system.     

基于信息理论的舰船噪声盲分离算法

目前水声信号处理方法大多基于信号和环境的特定统计假设 ,使用限制较大。当模型假设不成立时 ,会严重影响信号处理效果。本文导出了基于信息理论的舰船噪声盲分离算法。该算法利用当信号相互独立时的信息理论特性 (互信息量最小或熵最大 )作为分离准则 ,逐步学习确定分离矩阵。算法无需输入信号和混合矩阵的任何先验知识 ,实验仿真证明了算法的有效性。     

空间转动可变电镜图象的消卷

本文用漂白技术和提取衬度传递函数的方法,分别制作相位滤波器和振幅滤波器,对带有空间转动可变高分辨电子显微图象进行处理,明显地提高了图象的分辨率。     

内蒙古捕食性盲蝽及国内新纪录记述：半翅目：盲蝽科

记载了内蒙古捕食性或主要以捕食为生的盲蝽科昆虫２１种，隶属于２亚科６属，其中吸血盲蝽Ｈｙｐｓｅｌｏｅｃｕｓａｍｐｌｕｓ（Ｋｕｌｉｋ），小束颈盲蝽Ｐｉｌｏｐｈｏｒｕｓｃｌａｖａｔｕｓ（Ｌｉｎｎｅ），丝光束颈盲蝽Ｐ．ｌｕｃｉｄｕｓＬｉｎｎａｖｏｒｉ，显角微刺盲蝽Ｃａｍｐｙｌｏｍｍａｖｅｒｂａｓｃｉ（Ｍｅｙｅｒ—Ｄｕｅｒ）及环角微刺盲蝽Ｃ．ａｎｎｕｌｉｃｏｒｎｉｓ（Ｓｉｇｎｏｒｅｔ）等５种为中国新纪录天敌昆虫．     

对一个无证书部分盲签名方案的分析与改进

对汤鹏志等提出的一种无证书部分盲签名方案进行了密码分析,指出方案中签名请求者可以非法修改协商信息.为了有效抵抗篡改协商信息攻击,提出了一种改进的无证书部分盲签名方案.在随机预言机模型下证明了改进方案对无证书密码体制的两类敌手的自适应选择消息和身份攻击是存在性不可伪造的,其安全性可以归约为k-CAA问题和ICDH问题.     

一种单通道的周期性信号盲分离算法

提出一种针对周期性源信号的单通道盲源分离方法,该方法首先利用希尔伯特变换将单通道的混合信号表示为复数形式后,并用交叉互验技术来估计谐波分量的阶数,然后通过人工蜂群算法优化用于估计基频的代价函数以获得源数、基频及其谐波长度,最后由一种自适应滤波算法来估算源信号的幅值,从而实现了盲源分离的目的.仿真实验结果表明了该方法思路的可行性,且可达到"全盲"的要求.     

A novel artificial noise aided security scheme to resist blind source separation attacks

In this paper, we discuss the physical layer security from a new angle of view and propose a novel approach to resist some attacks in signal processing perspective. The scenario considered in this paper is that the eavesdropper has the similar channel performance compared to the legitimate receiver. We design the optimal artificial noise （AN） to resist the attacks of the eavesdropper who uses the blind source separation （BSS） technology to reconstruct the secret information. For speech signals, the optimal AN is obtained by minimizing the maximum of the correlation coefficients between the source signal and the received signals at Eve and the correlation coefficients between the source signal and separated results of BSS. For binary phase shift keying （BPSK） signals, we maximize the minimum bit error rates （BERs） of the separated signals and the obtained signals at Eve. Moreover, we consider the AN design from the point of breaking the BSS conditions, and propose a method by changing the correlation coefficient randomly. The simulation results show that the AN we proposed has better performance than that of the white Gaussian AN to resist the BSS attacks for both speech signals and the BPSK signals.     

基于自然梯度算法及其改进算法的盲源分离

自然梯度算法是盲源分离的重要方法,本文在介绍分析自然梯度算法基础上,将共轭梯度和自然梯度相结合改进了自然梯度算法的学习规则,通过两种算法的比较表明,基于共轭梯度改进的算法在性能和分离效果上都优于自然梯度算法。     

小波消噪和盲源分离在转子故障信号分析中的应用方法

针对转子振动信号不可避免地受噪声污染问题,提出了一种基于小波消噪和盲源分离相结合的信号分析方法.该方法首先利用小波滤波器对测试信号进行消噪处理,再利用信号的二阶统计量(SOS)来分离盲源信号.仿真和实验结果表明, 相对于直接对测试信号进行盲源分离的方法,本方法可更有效地提取出转子振动的本质信号特征.