A fuzzy diagnosis approach using dynamic fault trees

By incorporating digraph models, fault trees and fuzzy inference mechanisms in a unified framework, a novel approach for fault diagnosis is developed in this work. To relieve the on-line computation load, the fault origins considered in diagnosis are limited to the basic events in the cut sets of a given fault tree. The symptom occurrence order associated with each root cause is derived from system digraph with the qualitative simulation techniques. The implied candidate patterns are enumerated according to two proposed theorems and then encoded in the inference system with IF-THEN rules. The simulation results show that the proposed approach is not only feasible but also capable of identifying the most likely cause(s) of a hazardous event at the earliest possible time.     

准噶尔盆地不整合结构的地球物理响应及油气成藏意义

准噶尔盆地自成盆期以来经历了多期次构造运动,形成数个不整合。这些不整合在剖面上可分为5种类型,它们在地震上具有明显的反射特征。在纵向上,不整合分为3层结构,每层结构发育着多种岩石类型,它们在测井曲线组合上具各自不同的响应。不整合纵向的分层结构构成油气运移的双重通道,同时为油气聚集提供良好的储集空间和圈闭条件。尽管不整合的成藏条件有共同之处,但由于形成各类不整合时的应力强度、应力作用方式及地层变形程度等存在差异,导致不同类型的不整合还具有各自不同的油气成藏模式。      

应用人工神经网络优化五点法水平井井网

水平井直井联合布井方式越来越多地应用到油田的实际开发中，但是井网的选择与优化方面的研究比较少，特别是没有根据不同开发阶段变化的生产动态对水平井井网进行优化。应用人工神经网络技术，在进行数值模拟计算的基础上，制作样本并训练网络，可预测任意面积、任意水平井长度下的五点法水平井井网在不同开发阶段的生产动态，优化出不同生产时间和不同井网面积条件下最优井网穿透比，即生产10a时最优井网穿透比为0．55～0．8。与数值模拟结果进行对比，最大误差在1％以内，表明这种方法既快速简便又具有较高的精确性，可以有效地指导五点法水平井井网优化设计。     

提花织物意匠和纹板CAM系统

CAM系统的研制是从国情出发,保持传统产品特点和工艺要求,能适应多品种多规格的需要,有使用方便和通用性强的优点,并且在小样彩色图案的输入和识别处理、意匠过程中顺势间丝、影光、泥地处理等难题上有突破性发展,达到了实用要求。     

认真创建服务型企业拓展老水电厂发展空间——湖北省白莲河水力发电厂发展问题的思考

根据对白莲河电厂历史的与现状的分析,提出该厂应当由生产型向服务型转变,在服务中提高职工素质,拓展老水电厂的发展空间.     

鄂尔多斯西缘前陆盆地巨厚黄土地区地震采集技术

鄂尔多斯西缘前陆盆地表层地质地貌极其复杂，有巨厚黄土区、黄土-沙漠区及山前砾石-黄土区，独特的黄土地貌使得地震采集面临着诸多技术难题。根据以往巨厚黄土地区地震采集经验，采用多种方法系统地开展黄土表层结构精细调查，深入研究黄土地球物理特征及激发因素与表层黄土结构之间的关系，优选激发井位和井深，确保了激发效果；采用小道距、三线小线距、高密度空间采样技术，获得了高信噪比、高分辨率地震资料。研究表明，巨厚黄土地区地震采集时应优选激发井位和岩性，合理选择激发井深；坚持多深井组合激发、单井药量不宜过大总药量要大两项基本原则；采用高密度采样技术，提高采集资料的覆盖次数和信噪比。图10表1参15     

一种基于稳健匹配准则的视频文本跟踪方法

本文首先根据文本中各个字符的颜色相似的特性,确定已知文本块的文本的颜色,利用文本的颜色信息二值化文本图像以得到文本块中的字符数、字符的尺寸和间距;其次,根据视频图像的大小和视频的播放速度确定搜索窗口的大小,并利用文本的运动信息来预测搜索窗口的位置;第三,根据在相邻两帧中具有相同内容文本的颜色相似的特性,提出了一个可以解决脉冲噪声和部分缺损或遮挡问题的稳健匹配准则来跟踪文本块;最后,确定跟踪输出的文本的颜色、尺寸和运动方式。本文方法可以很好地跟踪平移、缩小或放大、旋转、淡入淡出和部分被遮挡的水平或倾斜排列的文本,并且可以记录文本平移、旋转和缩放的速度。     

Construction of a control system for disturbance rejection using a dual observer

A well‐known control system which can reduce the adverse effects of disturbances is a disturbance observer. However, in many cases of mechanical systems, system disturbances which do not satisfy the matching condition may be imposed. Therefore, it may be difficult to reduce the adverse effects of the disturbances by the traditional disturbance observer. In this paper, a method of control system synthesis for disturbance rejection using a dual observer is proposed. This method is based on the zeroing induced by the disturbance localization problem. This problem may be solved by dividing the state space into observable subspace and unobservable subspace. As compared with an H_∞ controller based on perfect observation, the usefulness of the proposed control system for disturbance rejection is demonstrated by numerical simulations for a two‐mass spring system. © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 50–60, 2002; DOI 10.1002/eej.1138     

Lateral space-charge effects on ballistic electron transport across graded heterojunctions

Hot electron transport across graded compound semiconductor heterojunctions has been explored using a two-dimensional formulation of the self-consistent ensemble Monte Carlo method. The Al_xGa_1-xAs/GaAs heterojunction imbedded into a vertical field effect transistor with two ohmic contacts (source, drain) and two lateral Schottky gates has been used as an example. Lateral space charges modulated by the gates are shown to control ballistic injection of electrons over the heterojunction under steady state conditions. The transient response to a gate pulse is found to be determined by carrier transit from the heavily doped source contact region into the channel. A conceptual one-dimensional section model is used to explain the Monte Carlo results.     

自干扰抵消盲空时DS-CDMA信号检测技术

针对传统单用户检测器存在远近效应和性能下界问题,近年来提出的一系列最大SINR准则盲空时RAKE接收机,可以较好地合并期望用户的多径分量,同时抑制多址干扰用户能量.本文对这类接收机进行了进一步的研究,提出了一种自干扰抵消方法,更有效地克服了单用户检测器存在的性能下界以及远近效应问题.仿真结果验证了本文方法的有效性.