恒温恒湿试验箱自适应逆控制系统的研究

本文针对恒温恒湿试验箱控制系统的难题,即多变量、非线性、强耦合以及大滞后的控制问题,提出了可行的研究方法和研究方案,并为自适应逆控制系统数学模型的建立设计了合理的实验方案、建模步骤。     

二语习得研究方法:CAS理论的视角

复杂适应系统理论理论为学者们研究语言提供了新的理论框架。本文就是在这一背景下尝试探讨其对研究方法的启示。在研究方法方面,二语研究方法上可以借鉴隐喻的思维方法和基于主体的建模方法。     

最小均方误差准则的自适应天线阵控零技术研究

本文针对基于最小均方误差准则的自适应天线阵方向图的控零技术进行研究。首先介绍了最小均方误差准则的基本理论,然后对基于该准则的自适应天线阵进行理论分析,最后对需要信号和干扰信号的到达方向发生改变以及干扰信号的幅值发生改变的两种情况阵的抗干扰性能。     

短时交通流混沌预测方法的比较

针对传统的应用数学模型方法在短时交通流预测精度和实时性方面存在的问题,提出了将Volterra滤波器自适应预测模型用于短时交通流的实时预测。为提高预测精度,在Volterra滤波系数计算过程中采用归一化最小均方自适应算法进行多次训练。应用该预测模型对几个典型的非线性系统进行预测,验证了算法的准确性。然后再用此方法对微观实测交通流的时间序列进行实证分析。仿真结果表明,该预测模型对实测交通流时间序列具有很好的预测效果,可以满足实时交通流预测的需要。     

基于自适应遗传算法的传感器网络数据融合算法

能源有效性是无线传感器网络(WSN)路由算法设计要考虑的首要问题,数据融合可以通过合并冗余数据而有效地节约能耗.提出了一种基于自适应遗传算法(AGA)的WSN数据融合算法,基于移动代理(MA)对Sink节点发出兴趣代理报文和目标节点发出数据代理报文进行转发.采用AGA求出MA最优路由节点序列,通过把WSN均匀分割为多个大小适当的二维网格,形成AGA的初始群体.仿真结果表明,随着网络规模增大,和局部最近邻优先算法(LCF)相比,该算法有更小的网络能耗和延时.     

Vertical adaptive radiation in ocean Prochlorococcus: Evolutionary implications of the Chl b/a ratio from molecular evidence

Prochlorococcus is a marine cyanobacterium of global significance. Two ecotypes are adapted to either high-light (HL) or low-light (LL) conditions. The ratio between chlorophyll (Chl) a and b is a distinguishing characteristic of these two ecotypes. However, how this ratio evolved in Prochlorococcus during this ecotype differentiation remains unclear. Our analyses reveal that the ancestor of Prochlorococcus was typically low-light adapted. The LL ecotype showed a stagnant evolution, and the HL ecotype was recently diverged. There was an adaptive radiation after directional evolution in the Chl b/a ratio regulation. Recombination in chlorophyllide a oxygenase (CAO) and positive selection on Clp protease contributed to the directional evolution of Prochlorococcus. The recombinant fragments of CAO were correlated with a large group of shared coevolving sites. Evidence of positive selection was found in both subunits of Clp. Chl b/a ratio evolution, as annotated by molecular evidence, appears to be among the crucial reasons that explain how Prochlorococcus has become the dominant photosynthetic organism in the ocean.     

Design of a 6.25 Gbps backplane SerDes with adaptive decision feedback equalization

A 6.25 Gbps SerDes core used in the high speed backplane communication receiver has been designedbased on the OIF-CEI-02.0 standard. To counteract the serious Inter-Symbol-Interference (ISI),the core employed a half-rate four-tap decision feedback equalizer (DFE). The equalizer used the Sign-signleast mean-squared (SS-LMS) algorithm to realize the coefficient adaptation. An automatic gain control(AGC) amplifier with the sign least mean-squared (S-LMS) algorithm has been used to compensatethe transmissio...     

高速光纤传输系统采用全通均衡器进行色散补偿的探讨

在分析了全通光均衡器的时延和色散特性的基础上,讨论了利用全通光均衡器进行色散补偿的原理,提出了评价全通光均衡器性能的参数和要求,介绍了色散补偿效果的评定方法,并给出了测试实例.     

基于小波网络的MQAM数字通信自适应均衡器

首先给出了多维小波网络的结构及其随机梯度学习算法,提出了基于小波网络的MQAM数字通信自适应均衡器.仿真结果表明:该均衡器对于MQAM数字信号非线性信道的均衡,其性能明显优于传统的基于LMS和RLS算法的线性均衡器和基于RLS算法的判决反馈均衡器,且性能稍好于基于BP网络的均衡器.     

CDMA系统中自适应阵列天线的改进算法

为改善调节阵列天线阵元权向量自适应算法的收敛稳定性 ,提出了一个改进算法。该改进算法不仅稳定、简单 ,而且能大大降低误码率。仿真结果对改进算法给予了有力的支持。