执行器故障时变系统的PID迭代容错控制

对存在执行器故障的连续线性时变系统，给出了PID型迭代学习容错控制律的收敛条件。对连续时变故障系统设计了一种PID迭代学习容错控制律，在[λ]范数意义下给出了故障系统PID型迭代容错控制器收敛的充要条件；基于Schur补原理和不等式变换，将容错控制器收敛条件转换成线性矩阵不等式，当迭代学习收敛速度设定时，基于线性矩阵不等式能快速确定最优迭代控制增益，避免了迭代控制增益设置的盲目性。旋转控制系统的数值仿真，验证了PID迭代容错控制器优良的容错性能和跟踪性能。     

解读理查德·帕多万的《比例——科学、哲学、建筑》

英国建筑学家理查德·帕多万所著的《比例——科学、哲学、建筑》是一部探讨建筑比例和科学、哲学的关系的书,其主要目的是对建筑比例本身进行认识论的分析。该文对其进行了简要解读,同时,也提出了几点不足和个人体会。     

重载提升台同步液压系统仿真设计

介绍采用D&C system simulator软件,对重载提升台两只油缸同步液压系统仿真设计。通过对两只液压缸升降过程同步精度(相对位置误差)和速度稳定性进行分析,对存在的问题进行了改进,保证了液压系统运行平稳可靠。     

基于PLC的自动封塑灌装机控制系统设计

为提高系统运行效率,设计自动封塑灌装机控制系统。运用PLC技术和PID调节技术,控制加热棒的温度,同时控制包装薄膜的送给长度,使得该系统运行效率有显著提高;采用HMI来设计系统的操作控制、报警显示、延时设定、温度设定及产量显示界面,同时触摸屏与PLC进行实时通信,以满足用户对功能的需求;最终通过合理选取系统硬件,实现了封塑过程中加热棒温度的实时、可靠控制。     

BP神经网络在开采沉陷相似材料配比中的应用

相似材料模型试验是矿山开采沉陷机理研究的重要研究方法,相似材料配比是实现相似材料模型模拟可靠性的关键因素。由传统试验方法确定相似材料配比费时、费力。综合分析了相似材料选择原则,以中国矿业大学研究制作的相似材料配比表为基础,建立了相似材料配比的BP神经网络模型。以33组试验数据作为训练和测试样本,模型预测的最大相对误差为7.39%。研究表明:所建立BP神经网络模型可基本反映出相似材料抗压、抗拉强度与各材料配比之间的内在影响规律,用该模型进行相似材料配比预测是可行的。     

焦家金矿尾砂固结充填配比优化研究

为解决焦家金矿上向进路充填接顶困难、成本高等技术难题,对现场尾砂固结材料的物理力学性质和化学组成、优化配比以及作用机理进行了分析和研究.结果表明,焦家金矿尾砂固结材料物化性能符合充填需要;推荐一步骤回采进路充填灰砂配比为1∶20,二步骤回采进路先用分级尾砂非胶结充填,顶部0.4～0.5 m用灰砂比1∶10的材料浇顶.     

新型污垢热阻在线监测仪的研制

为了实现对循环水结垢情况的监测,介绍了一种用于监测换热器的新型污垢热阻在线监测仪的设计方案.该监测仪采用高集成度微控制器和设计优良的电路,实现了对多路测量信号的采集处理以及污垢热阻的计算.同时,还可通过控制信号的输出实现对监测换热器系统中水流量及蒸汽温度的改进型数字PID控制.测试表明,该监测仪性能优良,并且对循环水结垢的在线监测起到了很好的效果.     

C60高强混凝土在某工程中的应用

高强混凝土具有强度高、耐久性好、变形小、经济性好等优点。本文以某工程为例,详细介绍了高强混凝土原材料选择,混凝土配合比,混凝土生产,混凝土施工,质量控制等内容。     

Flexible surrogate marker evaluation from several randomized clinical trials with continuous endpoints, using R and SAS

The evaluation of surrogate endpoints is thought to be first studied by Prentice, who presented a definition of a surrogate as well as a set of criteria. These criteria were later supplemented with the so-called proportion explained after notifying some drawbacks in Prentice's approach. Subsequently, the evaluation exercise was framed within a meta-analytic setting, thereby overcoming difficulties that necessarily surround evaluation efforts based on a single trial. The meta-analytic approach for continuous outcomes is briefly reviewed. Advantages and problems are highlighted by means of two case studies, one in schizophrenia and one in ophthalmology, and a simulation study.One of the critical issues for the broad adoption of methodology like the one presented here is the availability of flexible implementations in standard statistical software. Generically applicable SAS macros and R functions are developed and made available to the reader.     

Symmetry Partition Sort

In this paper, we propose a useful replacement for quicksort‐style utility functions. The replacement is called Symmetry Partition Sort, the principle of which is similar to that of Proportion Extend Sort. The main characteristic of the new algorithm is that it always places partially sorted inputs (used as a basis for proportional extensions) at each end of an array when entering the partitioning routine. This is advantageous in speeding up the processing for partitioning. The library function we developed based on the new algorithm is more attractive than the Psort library function introduced in 2004 because of its simple implementation mechanism, clearer source code, and faster operation with a performance guarantee of O(n log n). Increased robustness and adaptivity also make it highly competitive as a library function. Copyright © 2007 John Wiley & Sons, Ltd.