程控交换机收号系统模拟的研究

本文提出了一种模拟程控交换机收号系统的有效方法,采用消息驱动收号事件表的思想,运用并发控制技术,实现了在没有话路硬设备的条件下多用户同时拨号在线模拟收号控制的功能。本文提出的收号系统模拟方案已成功应用于某国产中大容量程控交换机的呼叫模拟系统中。     

A parallel hp‐FEM infrastructure for three‐dimensional structural acoustics

This paper describes a parallel three‐dimensional numerical infrastructure for the solution of a wide range of time‐harmonic problems in structural acoustics and vibration. High accuracy and rate of error‐convergence, in the mid‐frequency regime,is achieved by the use of hp‐finite and infinite element approximations. The infrastructure supports parallel computation in both single and multi‐frequency settings. Multi‐frequency solves utilize concurrent factoring of the frequency‐dependent linear algebraic systems and are naturally scalable. Scalability of large‐scale single‐frequency problems is realized by using FETI‐DP—an iterative domain‐decomposition scheme. Numerical examples are presented to cover applications in vibratory response of fluid‐filled elastic structures as well as radiation and scattering from elastic structures submerged in an infinite acoustic medium. We demonstrate both the numerical accuracy as well as parallel scalability of the infrastructure in terms of problem parameters that include wavenumber and number of frequencies, polynomial degree of finite/infinite element approximations as well as the number of processors. Scalability and accuracy is evaluated for both single and multiple frequency sweeps on four high‐performance parallel computing platforms: SGI Altix, SGI Origin, IBM p690 SP and Linux‐cluster. Results show good performance on shared as well as distributed‐memory architecture. Copyright © 2006 John Wiley & Sons, Ltd.     

Research and Development of the Profibus-dp Card Based onWin CE.net

At present, the intelligent protocol chip - ASPC2 to set up the PROFIBUS- DP master station are so often used. In consideration of the price of the project and the advantage of the embedded system,we choose the PROFIBUS - DP protocol card, which is developed by ourselves.And we put it into the embedded system set by Win CE.net + ARM9.It is a totally new trial.Our embed- ded maser station is based on the Microsoft Windows CE. net operating system (OS) and the SAMSUNG SMDK2410…     

Mechanical Properties and Bake Hardening Behaviour of two Cold Rolled Multiphase Sheet Steels subjected to CGL Heat Treatment Simulation

In recent years, multiphase steels have become a material of choice for use in the car manufacturing industry owing to their excellent mechanical properties. It is anticipated that in the years to come these steels will show the highest increase in usage. A particular aspect of their potential is that multiphase steels often show good bake hardening (BH) properties. The main factors that govern the microstructures and the properties of these steels are the chemical composition and the production process parameters. In this work two commercial cold rolled sheet steels with different carbon content were investigated. In order to produce dual phase (DP) steels with a ferrite‐martensite microstructure, the as‐received material was subjected to heat treatment simulating continuous galvanising line (CGL) cycles with an overageing zone before the zinc pot. After a first CGL cycle predominantly ferritic microstructures with small amounts of martensite, pearlite and retained austenite were obtained, which resulted in deviations from typical DP properties, e.g. in the occurrence of discontinuous yielding. A higher line speed led to improved mechanical properties. BH prestrain was varied between 0 and 10%. While only very little bake hardening was observed without prestrain, with increasing prestrain the amount of BH was evolving quickly towards larger values of more than 60 MPa. Generally, the BH values were somewhat larger for higher carbon content. Finally, an optimised CGL cycle was simulated at laboratory scale with changes in the process parameters. Thus, characteristic DP microstructures resulting in desired mechanical properties were obtained. For these optimised conditions, BH₂ values in excess of 60 MPa were achieved for both steels investigated.     

基于现场总线的电动执行机构在电站工程的应用研究

文章通过对Profibus DP总线技术及其应用的综合论述，分析了现场总线电动执行机构的应用优势和需要注意的问题。针对基于Profibus DP总线协议的AUMA一体化电动执行机构，具体阐述了其在浙江国华宁海电站一期工程的硬件构架、上位机组态和操作的实现，从而真正体现基于现场总线技术的电动执行机构的安全性、经济性。     

语音识别中DTW特征匹配的改进算法研究

采用基于动态规划方法的动态时间归正技术DTW(Dynamic Time Warping),可成功解决语音信号特征参数序列比较时时长不等的问题.在基于DTW的特征匹配用改进的动态时间归正方法将模板特征序列和语音特征序列进行匹配的基础上,比较两者之间的失真,得出识别判决的依据.实验表明,改进后的算法在孤立词语音识别中获得了良好性能.     

基于MC9S12DP256的AMT系统的设计

AMT(机械式自动变速器)是在机械式变速器的基础上发展起来的一种自动变速器,文章对其工作原理及结构组成进行了简要介绍,并且完成了以MC9S12DP256微控制器为核心的电子控制单元的硬件系统设计,通过在AMT中应用MC9S12DP256来实现对AMT系统的控制。同时系统中采用Freescale公司的高端驱动芯片MC33289来实现对电磁阀的驱动,系统结合自身CAN模块,选用Philips公司的PCA82C250设置了CAN的接口电路,用于故障码的传输以及与其他系统之间进行CAN通讯。     

基于Matlab的0-1背包问题的动态规划方法求解

背包问题是经典的NP-hard组合优化问题之一,在经济管理、资源分配、投资决策、装载设计等领域有着重要的应用价值。文中用动态规划方法解决0-1背包问题,通过在Matlab6.5环境下对其算法进行测试和与其他方法对比分析,表明应用该方法可节省大量的计算时间,因而具有更高运行效率。     

PLC在玻纤湿法毡卷绕系统中的应用

介绍用西门子可编程控制器S7-314C-2DP与Lenze变频器之间，通过PROFIBUS-DP通讯控制，实现对玻璃纤维湿法薄毡的自动卷绕。详细说明了系统组成、工作原理、张力控制分析及调整，并对软件设计做了简单的介绍。     

一种基于分层回溯的数据库查询优化算法

结合DP算法和回溯法的基本思想，提出了一种新的基于分层回溯的查询优化算法。其在优化简单查询时，可以提供“最优”的方案；对于一些复杂的应用环境，它可以在杖举算法的高复杂性和算法产生方案的质量之间取得一个权衡点，以产生“次优”的优化结果来换取算法的执行效率，大大节省了运行环境的资源。