双机械臂协调：以运动学为基础的模型分析与动态补偿控制方法

本文建立了双机械臂协调系统的主从式控制的非结构模型，并针对两臂具有相同特性和不同特性这两种情形作了稳定性分析，提出特性校正的方法，本文还利用内模原理设计出动态补偿器来克服标定约束的不确定性对系统控制品质的影响，最后给出了实验结果。     

Dynamic elastic-plastic behaviour of whipping pipes: experiments and theoretical model

This paper is concerned with the problem of pipe whip, the dynamic response of a high pressure piping system subjected to an end force as the result of a pipe break which releases a jet of fluid from the broken section. Both experimental and theoretical results are presented concerning the dynamic elastic-plastic behaviour of cantilever pipes subjected to a transverse force pulse at the free end. Comparisons between experimental data and theoretical predictions are made for mild-steel pipes with outer diameter-to-thickness ratios of 19.5, 28 and 32. It is demonstrated that, for these geometries, the whipping pipes display three characteristically different responses, viz. elastic, plastic hardening behaviour for thick pipes, elastic, plastic hardening-softening behaviour for moderately thick pipes and elastic, plastic hardening-softening-collapse behaviour for thinner pipes. The experimental data taken from a series of high-speed films are compared with the predictions of the instantaneous shapes of the whipping pipes derived from both a rigid, perfectly-plastic, large deflection, dynamic beam model and a more comprehensive model which incorporates the effects of elasticity and plastic hardening and softening, the details of which are presented in the paper.     

动态交通分配中一类转换率系统的稳定性

在假设交通很拥挤同时交通的转换率与路径费用成正比的前提下，构建了一个动态的转换率模型．为了获取转换率系统的全局渐近稳定，提出了一个普遍适用的Lyapunov函数方法，与此同时通过线性矩阵不等式方法，得到了保证转换率系统全局渐近稳定的充分条件．     

动态矩阵控制系统稳定域的根轨迹分析

本文使用根轨迹技术从理论上分析了纯滞后工业过程参数变化对系统稳定性的影响,得到了一个与设计参数有关的稳定域,从而为设计参数自动整定提供了参考。     

Multiobjective dynamic load-dispatching method for optimal operation of power systems

A new practical method is proposed which gives a quasi-optimal solution of the dynamic load-dispatching problem formulated by a multiconstraint multiobjective optimization problem. Here, the multiple constraints are rate reserve constraints and power flow ones, and the multiple objectives are fuel cost and CO₂ emission. The proposed method is an integration of the following three techniques: (1) “Group Dispatch Scheme,” which is developed by the authors, is used to satisfy a violated constraint easily. This scheme consists of three steps. The first step is to classify all generators into two groups. One is the group which should be more loaded to satisfy the violated constraint, and the other is the should-be less loaded group. The second step is to add some load to the former group, and to subtract the same load from the latter. The third step is to dispatch each group load to each groups generators, respectively; (2) the dynamic load-dispatching algorithm is used which provides, in practical time, quasi-optimal generation trajectories; (3) the conventional weighting parametric method is used to obtain a Pareto optimal solution of multiobjective problems. The effectiveness of the method is clarified by a computer simulation on the actual power system of Kansai Electric Power Company.     

液压激振系统的检测与控制

本文阐述一种用于控制液压激振装置加载力和加载频率的机液电系统。简要叙述液压激振器的基本原理和特点。分析了双闭环控制回路。重点介绍激振力和激振频率的检测和处理技术。     

34CrMoV结构钢动态再结晶行为研究

应用Gleeble-1500热模拟实验机进行等温压缩试验,研究了变形工艺参数对34CrMoV结构钢动态再结晶行为的影响.结果表明,其流变应力随变形温度升高而降低,随应变速率提高而增大;随着应变速率的降低,应变量的增加和变形温度的升高,动态再结晶速度加快且奥氏体晶粒得到细化.     

组态软件在应用中的功能扩展

在DDE动态数据交换基础上,采用本地以太网UDP用户数据报协议,解决了组态王不支持网络变量从本机输出的问题,完善了系统功能。     

Binary rewriting and call interception for efficient runtime protection against buffer overflows

Buffer overflow vulnerabilities are one of the most commonly and widely exploited security vulnerabilities in programs. Most existing solutions for avoiding buffer overflows are either inadequate, inefficient or incompatible with existing code. In this paper, we present a novel approach for transparent and efficient runtime protection against buffer overflows. The approach is implemented by two tools: Type Information Extractor and Depositor (TIED) and LibsafePlus. TIED is first used on a binary executable or shared library file to extract type information from the debugging information inserted in the file by the compiler and reinsert it in the file as a data structure available at runtime. LibsafePlus is a shared library that is preloaded when the program is run. LibsafePlus intercepts unsafe C library calls such as strcpy and uses the type information made available by TIED at runtime to determine whether it would be ‘safe’ to carry out the operation. With our simple design we are able to protect most applications with a performance overhead of less than 10%. Copyright © 2006 John Wiley & Sons, Ltd.     

Radiosity with Well Distributed Ray Sets

In this paper we present a new radiosity algorithm, based on the notion of a well distributed ray set (WDRS). A WDRS is a set of rays, connecting mutually visible points and patches, that forms an approximate representation of the radiosity operator and the radiosity distribution. We propose an algorithm that constructs an optimal WDRS for a given accuracy and mesh. The construction is based on discrete importance sampling as in previously proposed stochastic radiosity algorithms, and on quasi Monte Carlo sampling. Quasi Monte Carlo sampling leads to faster convergence rates and the fact that the sampling is deterministic makes it possible to represent the well distributed ray set very efficiently in computer memory. Like previously proposed stochastic radiosity algorithms, the new algorithm is well suited for computing the radiance distribution in very complex diffuse scenes, when it is not feasible to explicitly compute and store form factors as in classical radiosity algorithms. Experiments show that the new algorithm is often more efficient than previously proposed Monte Carlo radiosity algorithms by half an order of magnitude and more.