Design of the signal processor for an ionospheric sounding system

On the basis of the analysis of the system sounding principle, this paper introduced a new type of ionospheric oblique backscattering sound system, which is based on the pseudo- random noise phase modulated pulse compression. According to the high requirements of real-time and a large amount of computation and echo characteristics, a high-speed real-time signal processing system was established and the design of system hardware and software was focused on. The sounding results indicate that the system is equipped to handle the data fast and has a high degree of software features. It is of great significance for the realization of fast, real-time ionospheric sounding means.      

数字信号处理课程多教学模式的探索

针对数字信号处理课程教学中存在的问题，提出如何在注重理论教学的同时，结合实际抓好应用教学的理念。文中从基础学习、提高学习、兴趣学习3个方面采用不同形式的教学模式，使学生从被动学习到主动学习，乃至兴趣学习，旨在提高学生的知识运用能力和独立分析解决问题的能力。     

基于神经网络的自适应滤波研究

自适应信号处理在信号处理中占据主要地位,自适应滤波又是自适应信号处理中的主要应用.目前对自适应滤波的研究主要集中在算法上,但很难在收敛速度、稳定性和跟踪性能上同时取得最佳性能.综合考虑自适应滤波的各种性能,研究基于神经网络的自适应滤波方法,并通过实例应用来证明了该方法的有效性.该研究对拓展自适应滤波方法和神经网络的应用都具有重要的参考价值.     

Universal Distributed Estimation Scheme for a Bandwidth Constrained Ad Hoc Sensor Network

This paper describes a distributed estimation scheme (DES) for a bandwidth constrained ad hoc sensor network.The DES is universal in the sense that operations on all sensors are identical and independent of noise distribution.The scheme requires each sensor to transmit just a 1-bit message per observation.Simulation results show that the scheme achieves much better mean-squares error (MSE) performance than the simplified isotropic universal DES and even outperforms the isotropic universal DES which requires more than twice the bandwidth of this scheme.     

基于matlab的图像版权认证系统的GUI设计

设计了Chirp类图像水印系统的图形用户界面（GUI）．可以很方便地实现Chirp水印的嵌入、鲁棒性测试以及水印检测，系统操作方便，可视效果好，有利于版权认证系统的市场化．     

基于MATLAB与LabVIEW的信号处理分析与研究

针对MATLAB与LabVIEW软件的不同特性,提出利用编程实现和虚拟实验相结合的方式对信号进行处理,并以快速傅里叶变换FFT、信号的滤波,频谱分析为例,说明了这两种软件在信号处理中的特点及优劣性。通过实例表明采用MATLAB与LabVIEW两种软件可以实现动态演示和仿真分析的有机结合,从而可以提高信号处理的快捷性,直观性与可靠性。     

Satellite Image Adaptive Restoration Using Periodic Plus Smooth Image Decomposition and Complex Wavelet Packet Transforms

A satellite image adaptive restoration method was developed that avoids ringing artifacts at the image boundary and retains oriented features. The method combines periodic plus smooth image decomposition with complex wavelet packet transforms. The framework first decomposes a degraded satellite image into the sum of a "periodic component" and a "smooth component". The Bayesian method is then used to estimate the modulation transfer function degradation parameters and the noise. The periodic component is deconvoluted using complex wavelet packet transforms with the deconvolution result of the periodic component then combined with the smooth component to get the final recovered result. Tests show that this strategy effectively avoids ringing artifacts while preserving local image details (especially directional textures) without amplifying the noise. Quantitative comparisons illustrate that the results are comparable with previous methods. Another benefit is that this approach can process large satellite images with parallel processing, which is important for practical use.     

大鼠再生肝8种细胞的PPARγ信号通路相关基因转录谱预示脂类代谢活动

为了解大鼠肝再生中肝细胞、胆管上皮细胞、卵圆细胞、星形细胞、窦内皮细胞、库普弗细胞、陷窝细胞、树突状细胞等8种肝脏细胞的PPARγ信号通路相关基因转录谱及其预示的脂类代谢活动,按本卷2期张丽君[1]等方法分离大鼠再生肝8种细胞,检测它们的PPARγ信号通路基因表达谱,分析其预示的生理活动.结果表明,41个PPARγ信号通路相关基因在大鼠肝再生中发生了有意义的表达变化,其中上调、下调和上/下调的基因为9、9、23个,呈现15种表达相关性.相应细胞的基因数为10、6和1,10、12和2,7、7和0,16、8和3,18、7和1,10、6和1,11、20和0,13、9和4.它们的转录谱预示,胆管上皮细胞和星形细胞的脂肪合成、星形细胞和树突状细胞的胆固醇代谢、8种肝脏细胞的脂肪酸运输和脂肪细胞分化、星形细胞、窦内皮细胞和树突状细胞的脂肪酸氧化和糖异生、胆管上皮细胞和树突状细胞的能量代谢增强.上述结果表明,PPARγ信号通路与大鼠肝再生密切相关.     

突触信号传导的动态饱和模型研究

对一类动态饱和突触神经模型中信号传导性质进行了研究.模型的动态过程采用高阶Milstein随机微分方程解法进行求解,其信号输入输出特性用集平均互相关系数进行衡量.集平均互相关系数的数值分析结果表明,适宜的噪声能够增强信号传导,并且通过调节饱和势比值大小和突触神经群体数目,观测到噪声增强信号传导的非线性现象更加显著.     

Embryo retention,character optimization,and the origin of the extra‐embryonic membranes of the amniotic egg

This study summarizes the data relevant to understanding the appearance of the amniotic egg and provides new analyses to determine the inferences that can be drawn from these data. A survey of the recent literature shows that a consensus exists on the probably primitive absence of extended embryo retention in caecilians, despite recent suggestions to the contrary. The two most recent studies on the evolution of embryo retention in sarcopterygians both suggest that early amniotes lacked extended embryo retention. New analyses of length distribution of random trees suggest that the data on embryo retention do not include a phylogenetic signal, and this implies that character optimization of these data does not yield reliable information on the primitive condition for amniotes. Thus, the study of ancestral features of amniotes will probably have to exploit data from the fossil record.