On learning transient,auto-tunings of learnable bandwidth and lead step in iterative learning control

The learning transient and tracking accuracy of phase lead compensation iterative learning control are determined by its three parameters: learning gain, system learnable bandwidth and lead step. Because of the model inaccuracy, the learnable bandwidth is often chosen as a conservative value, which often degrades the learning performance. In this article, the learning transient is analysed and the tuning of learnable bandwidth and lead step are developed to achieve good learning transient and tracking accuracy simultaneously. The attractive properties include that the less dependence on system model and that the tracking error during this process keeps at a very low level. Experimental results on an industrial robot are presented to verify the tuning process.     

Effects of actuator and sensor bandwidths in intelligent cruise control of autonomous vehicles. Part II: performance

We analyse disturbance rejection for a platoon of vehicles with intelligent cruise control, both for the spatially discrete model and the continuum model with open and periodic boundary conditions. By explicitly calculating the eigenmodes for both the discrete and the continuum models, we derive the dynamic response of an individual discrete mode, as well as the response of a single vehicle to disturbances generated through either boundary vehicles or vehicles within the platoon. It is shown that if the biasing is small then the n-mode truncated continuum model and the spatially discrete model predict same qualitative responses to disturbances for the lower order modes. In the case of periodic boundary conditions, the two types of models predict quantitatively the same responses to disturbances for a range of feedback gains.     

隧道中无线信道的相干带宽研究分析

为了研究井巷内无线信道的相干带宽,在射线跟踪模型的基础上,推导关于频率差的相关系数公式,在推导的公式中,载波频率、传播距离、天线位置是影响信道相干带宽的重要参数,通过仿真分别分析了上述参数对信道相干带宽的影响。得出结论：井下巷道内的相干带宽与频率成正比,与传播距离成反比。     

天线引导数据对伺服跟踪的影响分析

针对目前在天线跟踪系统中普遍采用的数字引导工作方式,结合设计实例详细分析了数字引导方法在引导数据传输率等方面对系统跟踪精度造成的影响.最后结合工程实践,给出了几种减小或消除此类影响的方法,对提高伺服系统的跟踪精度有较大作用.     

Carrier‐sense‐assisted adaptive learning MAC protocols for distributed wireless LANs

A Carrier‐sense‐assisted adaptive learning MAC protocol for wireless LANs, capable of operating efficiently in bursty traffic wireless networks with unreliable channel feedback, is introduced. According to the proposed protocol, the mobile station that is granted permission to transmit is selected by means of learning automata. At each station, the learning automaton takes into account the network feedback information in order to update the choice probability of each mobile station. The proposed protocol utilizes carrier sensing in order to reduce the collisions that are caused by different decisions at the various mobile stations due to the unreliable channel feedback. Simulation results show satisfactory performance of the proposed protocol compared to similar MAC protocols. Copyright © 2005 John Wiley & Sons, Ltd.     

H robust stabilizability

In this paper, we improve on the results of robust stabilizability obtained by Kimura. We do this in a constructive way by using an H^∞-approach, and exhibit an upper bound for the order of robust controllers.     

高增益四级运放频率补偿技术

为改善四级运放不易稳定和单位增益带宽较窄的特性,提出一种新的四级运放频率补偿技术.采用多路嵌套式密勒补偿技术,实现左半平面零点和右半平面零点分离,并通过额外增加一条前馈通路产生左半平面零点,抵消了一个极点,简化了四级运放的频率补偿问题.通过将次极点向高频的推移以及次极点和单位增益带宽比例大小的合理设计,不仅保证了运放的稳定,同时增大了运放的单位增益带宽.经台积电(TSMC)0.25μm互补金属氧化物半导体(CMOS)混合信号工艺仿真和流片测试结果显示,该四级运放仅消耗0.842mW功耗,0.150mm2的芯片面积,在3.6V电源电压下具有60.15°的相位裕度,2.42MHz的单位增益带宽,大于150dB的直流增益.     

Plug-in Selection of the Number of Frequencies in Regression Estimates of the Memory Parameter of a Long-memory Time Series

We consider the problem of selecting the number of frequencies, m , in a log-periodogram regression estimator of the memory parameter d of a Gaussian long-memory time series. It is known that under certain conditions the optimal m , minimizing the mean squared error of the corresponding estimator of d , is given by m ^(opt)= Cn ^4/5, where n is the sample size and C is a constant. In practice, C would be unknown since it depends on the properties of the spectral density near zero frequency. In this paper, we propose an estimator of C based again on a log-periodogram regression and derive its consistency. We also derive an asymptotically valid confidence interval for d when the number of frequencies used in the regression is deterministic and proportional to n ^4/5. In this case, squared bias cannot be neglected since it is of the same order as the variance. In a Monte Carlo study, we examine the performance of the plug-in estimator of d , in which m is obtained by using the estimator of C in the formula for m ^(opt) above. We also study the performance of a bias-corrected version of the plug-in estimator of d . Comparisons with the choice m = n ^1/2 frequencies, as originally suggested by Geweke and Porter-Hudak (The estimation and application of long memory time series models. Journal of Time Ser. Anal. 4 (1983), 221–37), are provided.     

高分辨率单脉冲测量雷达接收机的设计

根据某些测量雷达提出的较高分辨率的要求，详细介绍高分辨率单脉冲测量雷达接收系统的理论分析和方案论证，并给出具体的实施方案。     

费用非对称通信网络上的群播路由算法

文中考虑了费用非对称通信网络上的群播路由问题,提出了一种接近最小成本的启发式算法--NEW-GM算法.该算法以FMPH(Fast Minimum Path Cost HouriStic)为基础,可以有效的降低成本.数值实验表明:这种算法是有效的,且所获得问题解的总费用几乎总是小于或等于由GTM算法所获得的解的总费用.NEW-GM算法的时间复杂度与GTM算法的相同,为O(p3n2).