电动自行车调速控制电路的改进

通过对某种调速控制器的剖析及试验,找出了原控制器使用过程中频繁烧坏功率场效应管的原因,斫制出了一 种改进型控制器电路,从根本上解决了原电路存在的问题。文章阐述了改进型电路的设计方法,并给出了电路原理图。     

用Visual Basic设计虚拟PLC软件界面

在使用Visual Basic 6.0开发可编程控制器虚拟软件的过程中,设计软件界面时采用了几种方法,取得了良好的效果。对这些方法的作用、优点和注意事项进行了阐述,并提出了一些可以考虑的其它方法或建议。     

Heuristic approach to some laws for Brownian motion

Csàki and Vincze have shown that for an elementary tied-down random walk, the pair (maximum, instant of maximum) has the same law as (time spent in (0, 1/2), time spent above 1/2). Formal passage to the limit indicates that the former pair has for a Brownian bridge the same law as (local time at 0, duration of positivity). A quadrivariate density of Karatzas and Shreve and an equivalence for Brownian motion with drift follow.     

计算机实时模糊控制一级倒立摆装置

本文通过分析模糊控制中语言控制规则的特点,提出了一种新的带修正因子的控制规则自调整方法,实时控制一级倒立摆装置的实验表明,这种设计方法是简单而且有效的。     

分形在超细微粒粒度测试中的应用

提出了用分形理论来建立微粒布朗运动特征模型的设想,并从理论上阐明了它的有效性。在此基础上进行分析,得到了模型的分形特征和微粒尺寸参数间的关系。结合图象信号处理技术,可从计算的分形维值中获取粒度信息,进而可得到一种超细微粒粒度测试的方法。     

论影视的表现手段

影视的表现手段主要有三个 ,即视觉元素、听觉元素和运动元素。视觉元素由画面与镜头构成 ,听觉元素由对话、音乐和音响构成。运动元素则由节奏和蒙太奇构成。这些元素各有其独特的功能 ,但在服务影视的前提下 ,又是互相联系和互补的     

低温下铁磁体畴壁运动的量子效应

本文用与受迫阻尼谐振子类比的方法，将经典的铁磁体畸壁运动方程量子化，讨论了畴壁的零点起伏，定性地给出了铁磁体畴壁运动量子效应出现的条件，并发现这一条件受多种因素的影响。     

A time-varying weights tuning method of the double EWMA controller

In recent years, the exponential-weighted-moving-average (EWMA) statistic based controllers are popular in semiconductor manufacturing. However, the single EWMA controller is not sufficient for compensating for the wear-out process. Thus, a double EWMA controller was proposed to enhance the capability for controlling the drifting process. In the literatures, in the solution of the double EWMA controller, only the “trade-off” solution weights are used to tune the controller. However, it is a fixed weight tuning method, and it is known that a time-varying weight will produce a superior performance over that of a fixed one (J. Quality Technol. 29 (1997) 184). Therefore, this study aims to develop a heuristic time-varying weights tuning method for the double EWMA controller. The numerical results showed that the proposed time-varying tuning method possesses an improvement of least 10% over that of the fixed weight scheme.     

基于项目驱动的三维动画类课程教学模式探析

文章通过分析传统三维动画类课程教学中存在的问题,提出了基于项目驱动式教学法与三维动画类课程结合的教学模式.以具体的三维动画设计课程为例,深入探讨了项目驱动教学法在三维动画类课程教学中的具体实现过程和项目模块内容的建设.其目的和意义在于探索三维动画类课程新的教学模式,为专业人才的培养开辟一条新的思路.     

An Approximation of Subfractional Brownian Motion

In this article, we obtain an approximation theorem for subfractional Brownian motion with H > 1/2, using martingale differences. The proof involves the tightness and identification of finite dimensional distributions.