灌区小面积地形图的简易测绘

阐述了灌区小面积地形图测绘时消除误差的方法。精度分析表明，该方法完全满足工程需要。     

Orthogonality of inductosyn angle-measuring system error and error-separating technology

0　INTRODUCTIONRoundinductosynhasadvantagesofhighprecision ,goodreliabilityandassemblingconveniently[1,2 ] .Itsangle measuringerrorsincludemainlythefirst orderlong period(36 0°)harmonicerror ,thesecond orderlong periodhar monicerror,thefirst ordershort periodharmonicerrorandthesecond ordershort periodharmonicerror .Aimingata36 0 poleroundinductosyn[4 ] ,Ref.[5 ]putsforwardamethodofhardwarecompensationforthefirst ordershort periodharmonicerrorandthesecond ordershort periodharmonicerror.T…     

一体化跟踪型测角系统的误差分析

为满足系统对位置检测的要求，有利于电机系统的小型化设计，提出了采用感应同步器与单片集成轴角变换器(AD2S80A)构成的跟踪型测角系统同时作为磁极位置检测环节和角度测量系统的一体化方案．分析了感应同步器及跟踪型测角系统误差，推导了由非有效电势产生的零位奇偶跳动导致的一次正弦变化测角误差等误差模型。实验结果证明了分析方法的正确性．     

分层空时码检测算法的研究

分层空时码技术是提高无线信道传输速率的一种十分有效的方法.迫零检测算法和最小均方误差检测算法是分层空时码体制中经常使用的两种检测算法,它们都使用了通常的线性合并置零技术,因此要求接收天线数不小于发射天线数,即要求在接收机上安装较多的天线,从而限制了分层空时码在移动环境下的应用.本文引入分层空时码的最大似然检测算法,突破了前两种算法对接收天线数的限制,并分别针对单路径和多径衰落信道环境,对分层空时码的三种检测算法的性能进行了仿真比较和分析,从而提出了它们各自适合的应用环境.     

Move limits definition in structural optimization with sequential linear programming. Part II: Numerical examples

A variety of numerical methods have been proposed in literature in purpose to deal with the complexity and non-linearity of structural optimization problems. In practical design, sequential linear programming (SLP) is very popular because of its inherent simplicity and because linear solvers (e.g. Simplex) are easily available. However, SLP performance is sensitive to the definition of proper move limits for the design variables which task itself often involves considerable heuristics. This research presents a new SLP algorithm (LESLP) that implements an advanced technique for defining the move limits. The linearization error sequential linear programming (LESLP) algorithm is formulated so to overcome the traditional limitations of the SLP method. In a companion paper [Comput. Struct. 81 (2003) 197] the basics of the LESLP formulation along with a guide to programming are provided.The new algorithm is successfully tested in weight minimisation problems of truss structures with up to hundreds of design variables and thousands of constraints: sizing and configuration problems are considered. Optimization problems of non-truss structures are also presented. The numerical efficiency, advantages and drawbacks of LESLP are discussed and compared to those of other SLP algorithms recently published or implemented in commercial software packages.     

两种标准信号之间的函数变换

用函数变换的方法解决两种标准信号之间的转换，进而阐述了数学在解决实际问题中的应用。     

基于IPSEC的VPN的安全功能要求的设计与分析

《计算机信息系统安全保护等级划分准则》是我国计算机安全产品和系统必须遵循的标准,而CC是一个新的国际性通用标准,设计一个满足CC标准的网络安全产品或系统,目前国内还没有借鉴之处。文章对国际国内的安全标准现状进行了分析比较,研究了将我国的计算机信息系统安全保护等级的要求用CC标准来描述的问题,并对基于IPSEC的VPN的安全功能要求的实现进行了研究。     

Degenerate Two-Phase Incompressible Flow IV: Local Refinement and Domain Decomposition

This is the fourth paper of a series in which we analyze mathematical properties and develop numerical methods for a degenerate elliptic-parabolic partial differential system which describes the flow of two incompressible, immiscible fluids in porous media. In this paper we describe a finite element approximation for this system on locally refined grids. This adaptive approximation is based on a mixed finite element method for the elliptic pressure equation and a Galerkin finite element method for the degenerate parabolic saturation equation. Both discrete stability and sharp a priori error estimates are established for this approximation. Iterative techniques of domain decomposition type for solving it are discussed, and numerical results are presented.     

消除卷积数值计算中的截尾误差的方法

有始无终信号的卷积在用数值计算方法来计算时会带来误差 ,包括截尾误差、近似误差和字长舍入误差 ,其中截尾误差往往较大。适当选取信号的长度 ,可以在相应时间段内消除截尾误差