空心圆柱试样真三轴仪应力路径的控制

介绍了新研制的空心圆柱试样真三轴仪内外腔加载压力独立控制的机电液光一体化电液伺服加载装置,以及由步进电机独立控制沿试样轴向方向的载荷和为实现主应力旋转在试样端面上施加设定的控制扭矩的加载装置。采用卡尔曼滤波及预报递推控制算法,克服步进电机加载系统与电液伺服加载装置响应速度不一致的问题,从而在连续加载试验中,使尽可能多的离散点遵循设定的加载应力路径。     

非线性系统模糊神经网络直接自适应控制

提出一种基于模糊神经网络的自适应控制方法。由模糊神经网络构成非线性预测器，利用使预测输出等于参考输出，生成实时控制信号。对自适应算法进行了理论分析，结合实例进行了仿真。     

时滞离散非线性系统基于NN预测的准滑模控制

研究一类具有输入滞后的离散非线性系统的准滑模控制问题。根据滑模控制原理和神经网络的逼近能力,提出了一种基于神经网络预测的准滑模控制器设计方法,给出了神经网络预测器的自适应算法。通过理论分析和仿真结果,证明了神经网络预测器的自适应算法是收敛的,闭环准滑模控制系统是稳定的,跟踪误差可收敛到零的一个领域内。     

带有扰动补偿的永磁同步电机自适应预测控制

为保证永磁同步电机(PMSM)控制系统的稳定性和鲁棒性,提出一种基于小波神经网络的自适应Smith预测控制器(WNNSPC),通过对模型误差的补偿,消除模型不确定性的影响,保证了预测输出的准确性,同时针对电机运行中突加负载等的扰动,采用小波神经网络进行前馈补偿,有效抑制了各类扰动对系统的影响,而且具有良好的动、静态品质。仿真结果证明了提出方法的有效性。     

Geographically distributed real-time digital simulations using linear prediction

Real-time (RT) simulator is a powerful tool for analyzing operational and control algorithms in electric power systems engineering. For understanding the dynamic and transient behavior of a power systems, significant RT computation capabilities are essential. A single unit of RT simulator has limited simulation capabilities. The most common way of augmenting simulation capability is using a bank of locally connected RT simulators. However, creating a large-sized bank of RT simulators involves significant financial investments and hence may not be feasible at all research facilities. Power and energy systems research facilities that use RT simulators are at diverse physical locations. In addition to RT simulators, research facilities around the world house an array of facilities with unique power, energy, and control systems for innovative research. To leverage these unique research facilities, geographically distributed RT simulation based on Wide Area Network (WAN) is required. Typical RT simulators perform simulations with time-steps in the order of milliseconds to microseconds, whereas data latency for communication on WAN may be as high as a few hundred milliseconds. Such communication latency between RT simulators may lead to inaccuracies and instabilities in geographically distributed RT simulations. In this paper, the effect of communication latency on geographically distributed RT simulation is discussed and analyzed. In order to reduce the effect of the communication latency, a Real-Time Predictor (RTP), based on linear curve fitting is developed and integrated into the distributed RT simulation environment. Two geographically distributed digital RT simulators are used to perform dynamic simulations of an electric power system with a fixed communication latency and the predictor. Empirical results demonstrate the effects of communication latency on the simulation and the performance of the RTP to improve the accuracy of simulations.     

Applied Nonparametric Statistical Methods

In the analysis of spatial data, it is common to predict a spatial exceedance and its associated exceedance region. This is scientifically important, because unusual events tend to strongly affect the environment. We use classes of loss functions based on image metrics (e.g., Baddeley's loss function) to predict the spatial-exceedance region. We then propose a joint loss to predict a spatial quantile and its exceedance region. The optimal predictor is obtained by minimizing the posterior expected loss given the process parameters, which we achieve by simulated annealing. Various predictors are compared through simulation. This methodology is applied to a spatial data set of temperature change over the Americas.     

The relationship between in-treatment abstinence and post-treatment abstinence in a smoking cessation treatment.

Previous research has indicated that abstinence early in a smoking cessation program is predictive of successful posttreatment abstinence. However, it has not been established whether or not this effect is independent of other in-treatment abstinence patterns. In this paper the relationship between three potentially important aspects of in-treatment smoking abstinence and posttreatment smoking abstinence are examined: early abstinence, extended abstinence, and end-of-treatment abstinence. We examined the relationship between smoking behavior measured each weekday over 70 visits (approximately 14 weeks) of a contingency management smoking cessation program and at a follow-up visit 6 months after study entry (3 months after the scheduled end of treatment). Ninety-five of 102 participants were successfully followed-up. Seven of these 95 participants were confirmed abstinent. Early abstinence, defined as abstinence during the first 10 treatment visits, was significantly and independently related to follow-up abstinence (OR = 56.67 [7.29–440.63]). Extended abstinence and end-of-treatment abstinence were related to follow-up abstinence, but not independent of early abstinence based on multiple regression models. Inclusion of a variety of demographic and environmental characteristics did not significantly alter this relationship. Thus, consistent with the previous literature, the establishment of early abstinence appears to be crucial to establishing longer-term abstinence, independent of other in-treatment abstinence patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

用于图像预测编码的预测器的设计及应用

设计并实现了一个用于图像预测编码的预测器。在图像压缩中,预测器是影响整个图像压缩比以及图像质量的关键环节。为了提高预测器的性能,本文结合了线性与非线性预测器的设计方法,首先对图像像素及其邻域像素之间的相关性估计值进行统计计算,确定该预测器的最佳阶数为四阶,接下来以预测差值的最小均方差标准和差值图像的期望值恒为零的约束为前提,同时对邻域模板的平坦程度加以分类,统计分析各类图像得出大量实验数据,最终设计出性能较好的四阶预测器。由于该预测器应用于星载图像的压缩,其预测系数在设计时兼备了便于硬件实现的特点。     

基于Smith预估器的单片机温控系统的实现

用1台单片机及相应的部件组成电阻炉炉温自动控制系统,采用Smith预估器克服系统较大的滞后性,给出了详细的系统结构图和程序流程图.     

Contributions of congruent pitch motion cue to human activity in manual control

The contribution of pitch motion cues to the performance of human pilots in compensatory tracking task are evaluated from pairs of uniquely planned experiments on a motion based research simulator, which allow separation of the visual responses from combined motion-visual responses. Analytical time series human pilot models of the least squares structure are evaluated from the input-output data and the results are discussed in terms of familiar parameters of pilot models and predictor operator. Beneficial contributions of pitch motion cues and subject differences are presented.