基于CH365型接口和MCX314As型运动控制器的PCI总线运动控制卡设计

以CH365型PCI总线接口和MCX314As型运动控制器为核心硬件,自主研发了基于运动控制器的PCI总线运动控制卡,该控制卡能够实现4轴位置、速度和S曲线的加减速控制,具有直线、圆弧、位模式插补功能及自动原位搜寻功能,同时具有4路信号输入和8路通用输出.     

Wood inspection with non-supervised clustering

Abstract. The appearance of sawn timber has huge natural variations that the human inspector easily compensates for mentally when determining the types of defects and the grade of each board. However, for automatic wood inspection systems these variations are a major source for complication. This makes it difficult to use textbook methodologies for visual inspection. These methodologies generally aim at systems that are trained in a supervised manner with samples of defects and good material, but selecting and labeling the samples is an error-prone process that limits the accuracy that can be achieved. We present a non-supervised clustering-based approach for detecting and recognizing defects in lumber boards. A key idea is to employ a self-organizing map (SOM) for discriminating between sound wood and defects. Human involvement needed for training is minimal. The approach has been tested with color images of lumber boards, and the achieved false detection and error escape rates are low. The approach also provides a self-intuitive visual user interface. Received: 16 December 2000 / Accepted: 8 December 2001 Correspondence to: O. Silvén     

An anti-plane crack perpendicular to the weak/micro-discontinuous interface in a bi-FGM structure with exponential and linear non-homogeneities

Treated was an anti-plane crack perpendicular to the interface of an exponential-type FGM strip bonded to another linear-type FGM substrate with infinite thickness. Through Fourier integral transform, the problem was reduced as a Cauchy singular integral equation, which was further solved numerically by the Lobatto–Chebyshev collocation method. Based on the numerical solution, the effects of the geometrical and physical parameters on the stress intensity factor (SIF) were analyzed and the following conclusions were obtained: (a) A notable discrepancy between the interface-perpendicular crack and the interfacial one is that, to reduce the weak-discontinuity of interface or to make the interface micro-discontinuous will not necessarily decrease the SIF of the former, but will surely decrease that of the latter. (b) When a crack tip is situated very near to the interface (or free surface), its SIF will be high and totally dominated by the interface (or free surface). (c) To increase the stiffness of the FGM on one side of the interface is beneficial to preventing the crack on the other side from growing toward the interface. Besides, some practical suggestions were further given for material design in the field of composites.     

高精度智能转速测量模板的设计

介绍了一种利用高性能的16位单片机80C196KC进行转速实时高精度的测量方法，阐述了如何通过CAN总线实现与微机通讯；详细描述了硬件电路的设计，并给出了软件程序框图。     

Modeling and performance analysis of IP access interface in optical transmission networks with packet switching

The article analyzes the influence of the Internet Protocol (IP) access interface on the packet loss probability and delay times in the optical packet switched network. The network and node model have been proposed, and the structure of the IP access interface, including assembler and holder, have been included in the analysis. It has been shown that the increase of the maximum optical packet sizes, as well as use of the holding feature as contention resolution mechanism, decrease the packet loss probability, but introduce delays at the optical network access points. Modeling and analysis were based on the discrete event simulation assuming self-similar traffic sources. IP packet lengths were modeled using empirical data. This work has been conducted while the author was affiliated with the Telecommunication Laboratory, Swiss Federal Institute of Technology (EPFL-STI-ITOP-TCOM), Lausanne, Switzerland     

码分多址（CDMA）技术和公用空中接口综述

本文主要讨论数字移动通信中扩频码分多址技术，阐明了ＣＤＭＡ体制的优越之外，分析了ＣＤＭＡ的关键技术，全面介绍了ＣＤＭＡ系统设计的基本原则和ＩＳ－９５－Ａ空中接口标准的含义。     

气泡－水相界面上传质过程的自相似分析解

应用自相似方法求解气泡－水相界上的传质问题，并获得了计算相界面上传质量的表达式。     

液相对流对固液界面稳定性的影响

以模型合金丁二腈－乙醇的强制性晶体生长为基础，利用自行研制的液相对流驱动装置，详细考查了液相自然对流及强迫对流作用下，模型合金平界面失稳的动态生长过程，证实了液相的流动加快了液相温度与浓度分布的均匀化，从而增强了液／固界面的稳定性。并且随流动速度的增加，界面稳定性提高。