Data errors in the computation of free motion

Input data in the computation of free motion (the inertia and stiffness matrices) contain some errors. These errors generate errors of output data (the natural frequency vector, the natural mode vectors). In this paper the relationships between errors of input and output data in the computation of free motion are derived. This analysis is applied to the finite element method. The paper presents program ERROR, which computes the errors of the natural frequencies created by the inertia matrix errors. An example of the influence of the errors of the mass and of the mass moment of inertia on the natural frequencies of a ship hull is presented.     

Tolerating spelling errors during patient validation.

Misspellings, typographical errors, and variant name forms present a considerable problem for a Clinical Information System when validating patient data. Algorithms to correct these types of errors are being used, but they are based either on a study of frequent types of errors associated with general words in an English text rather than types of errors associated with the spelling of names, or on errors that are phonologically based. This paper investigates the types of errors that are specifically associated with the spelling of patient names, and proposes an algorithm that effectively handles such types of errors. This paper also studies the effectiveness of several relaxation techniques and compares them with the one that is being proposed.     

软件代码缺陷分类及其应用

分析现有软件缺陷分类方法,基于对航空型号软件实施代码审查的实际经验,提出较完善的代码缺陷分类,将其应用于某航空型号软件代码审查,发现的缺陷占全部测试所得的75％。给出可以覆盖该缺陷类型的新类型。检验结果表明,该代码缺陷分类可以有效指导代码审查。     

Inherited error in finite element analyses of structures

Mathematicians are quick to point out that round-off and truncation errors induced by the digital computer are only half of the manipulation errors in numerical analyses. The other half are the errors in quantizing the mathematical problem for computer solution: errors inherited for the equation solving process.This paper examines the relevance of inherited errors in structural analyses using the finite element concept and the digital computer. It illustrates error magnitudes using numerical experiments of simple structures. It constructs a theory explaining the errors for these systems. Having identified the most significant controllable computer error source, it describes a process for minimizing its contribution to the inherited error.The paper concludes that orders of magnitude between errors reported by various investigators can be explained by differences in inherited error. The most significant effect of these errors can be identified with inconsistency in problem formulation. These inconsistencies can be eliminated by exploiting the existence of rigid body states in the finite element models. Thereby, solution errors introduced by inherited errors can be reduced to intrinsic errors in parameters defining the geometry, material characteristics, and boundary conditions.     

Detecting Data-flow Errors Based on Petri Nets With Data Operations

In order to guarantee the correctness of business processes, not only control-flow errors but also data-flow errors should be considered. The control-flow errors mainly focus on deadlock, livelock, soundness, and so on. However, there are not too many methods for detecting data-flow errors. This paper defines Petri nets with data operations (PN-DO) that can model the operations on data such as read, write and delete. Based on PN-DO, we define some data-flow errors in this paper. We construct a reachability graph with data operations for each PN-DO, and then propose a method to reduce the reachability graph. Based on the reduced reachability graph, data-flow errors can be detected rapidly. A case study is given to illustrate the effectiveness of our methods.      

中文文本自动校对中的语法错误检查

文章将中文文本的语法错误分为搭配错误和与句型成分相关的错误两大类。分别采用模式匹配的方法和基于句型成分分析的进行检查,这两种方法的结合,可以同时考虑局部和全局的语法限制信息,并且降低了语法检查的复杂度。通过对实验结果的分析和评测,证明文章所述的方法是可行的。     

Hardware-Related Software Errors: Measurement and Analysis

This paper describes an analysis of hardware-related software (HW/SW) errors on an MVS/SP operating system at Stanford University. The analysis procedure demonstrates a methodology for evaluating the interaction between hardware and software as it relates to system reliability. The paper examines the operating system's handling of HW/SW errors and also the effectiveness of recovery management. Nearly 35 percent of all observed software failures were found to be hareware-related. The analysis shows that the operating system is seldom able to diagnose that a software error may be hardware-related. The impact of HW/SW errors on the system is evaluated by measuring the effectiveness of system recovery in containing the propagation of HW/SW errors. The system failure probability for HW/SW errors is close to three times that for software errors in general. The observed HW/SW errors are seen to have a specific pattern, suggesting the possibility of the use of such error patterns for intelligent error prediction and recovery.     

机器人结构参数最优公差及关节最佳运动误差

本文给出了机器人位置和姿态误差的一种矩阵形式.根据矩阵原理,得到一个重要结论:若机器人位姿误差在其工作空间内达到最小,则机器人结构参数误差和关节运动误差矢必须等于位姿误差系数矩阵最小特征值对应的标准正交特征向量。本文还讨论了如何选择结构参数最优公差以及相应的关节最佳运动误差.最后结出了一个六自由度关节型机器人的数值计算。     

直接数字频率合成中幅度量化误差分析

直接数字频率合成中，由于ＲＯＭ的数据位字长有限，因此存放在其中的正弦波幅值有量化误差，这个量化误差将在Ｄ／Ａ输出端产生杂散分量。本文把量化误差看作周期序列，对其在Ｄ／Ａ输出端产生的杂散分量平均功率进行了讨论，并分析了它的频谱特性。     

基于NURBS曲线拟合的图像亚像素边缘提取方法

通过介绍激光扫描测量原理 ,说明准确地从光刀图像中提取光刀边缘位置是影响测量精度的关键因素 .由于噪声的存在 ,使用常见的边缘检测方法 ,在光刀图像中提取同一位置的光刀边缘 ,以及计算光刀中心位置 ,会带来很大的误差 .为了降低误差 ,本论文提出了基于 NURBS曲线拟合的亚像素光刀边缘提取方法 .通过实验 ,说明该方法重复提取的结果比较稳定 ,而且将误差控制在 0 .4个像素以下 ,从而使重复测量的高度误差在 0 .0 8mm以下     

Impact of inspection errors on the formulation of a multi-objective optimization process targeting model under inspection sampling plan

The literature on inspection systems has demonstrated that such systems are error prone. Such systems exhibit type I and type II errors. Type I error is classifying a conforming item as non-conforming while type II error is classifying a non-conforming item as conforming. The errors may arise from the measurement system or the inspectors. It is essential to assess the impact of the inspection errors on the optimal parameters and objective functions of process targeting models. The purpose of this paper is to assess the impact of the inspection errors on the optimal parameters and objectives functions values of Duffuaa and El-Ga’aly multi-objectives optimization model recently developed for process targeting (2013a). In order to accomplish the objectives of the paper, Duffuaa and El-Ga’aly multi-objective optimization model is extended by introducing the measurement errors in the inspection system and penalties to mitigate the effect of the errors. The results of the extended model is compared with the previous model and employed to studying the impact of the errors on the values of objective function and the optimal process parameters in a multi-objectives environment. The results indicated that inspection errors have significant impact on the profit and uniformity objectives.     

基于LSTM和N-gram的ESL文章的语法错误自动纠正方法

针对英语文章语法错误自动纠正(Grammatical Error Correction,GEC)问题中的冠词和介词错误,该文提出一种基于LSTM(Long Short-Term Memory,长短时记忆)的序列标注GEC方法;针对名词单复数错误、动词形式错误和主谓不一致错误,因其混淆集为开放集合,该文提出一种基于ESL(English as Second Lauguage)和新闻语料的N-gram投票策略的GEC方法。该文方法在2013年CoNLL的GEC数据上实验的整体F₁值为33.87%,超过第一名UIUC的F₁值31.20%。其中,冠词错误纠正的F₁值为38.05%,超过UIUC冠词错误纠正的F₁值33.40%,介词错误的纠正F₁为28.89%,超过UIUC的介词错误纠正F₁值7.22%。     

三维STL模型的快速成型关键技术研究

介绍了三维STL模型描述文件中存在的缺陷,分析了产生这些缺陷的原因,结合实际生产应用中的经验提出了对STL模型文件进行修复的实际可行的修补方法,给出了相关的计算机程序。     

Array errors active calibration algorithm based on instrumental sensors

The array mutual coupling,gain-phase errors and sensor position errors would significantly degrade the performance of high-resolution direction of arrival (DOA) estimation algorithms.Aiming at the combined influences of the above three array errors,a kind of active calibration algorithm is presented with the help of instrumental sensors in this paper.Firstly,the integrated effects of the three array errors are shown to be equivalent to angularly dependent gain-phase errors.Then,a non-linear least square (LS...     

基于辅助阵元的阵列误差有源校正算法

阵列互耦、幅相误差和阵元位置误差的综合影响会严重影响超分辨率算法的性能,为此,针对上述3种阵列误差的综合影响,给出了一类基于辅助阵元的有源校正算法.首先,将3种阵列误差的综合影响等效为一种依赖方位变化的幅相误差,并通过一种基于辅助阵元的自校正方法得到了关于3种阵列误差的非线性最小二乘优化模型;然后,针对阵列误差矩阵可能出现的不同模型,给出了相应的求解算法;接着,针对算法的参数估计唯一性给出了较为细致的分析,并对算法做了进一步改进;最后,通过仿真实验验证了新算法的有效性.     

量化误差对直线位姿估计精度影响的研究

针对直线位姿估计问题分析了量化误差的传播特性，并以闭式解的形式建立了位姿估计结果受图像量化误差影响的数学模型．同时，在分析量化误差传播特性的基础上，给出了直线的选线方法．最后，确定了最优直线配置，提高了位姿估计精度．     

A software for evaluating local accuracy in the fourier transform

With the evolution of computers toward ever increasing computing speed, the numerical algorithms implemented on such computers are more and more complex, and require a very great number of computations. The numerical errors inherent in floating-point arithmetic of the computer generate errors in the results which may be fairly great. In this paper we propose a software based on the Perturbation Method for estimating the local accuracy in the Fast Fourier Transform, both in the case of exact data (computing errors alone) and in the case of experimental data (data errors and computing errors).     

STL错误的手工修复方法研究

STL文件的错误会给后续处理带来很多不便。目前的自动修复算法和程序都只能修复部分简单的错误,无法满足实际的需要。对于含有复杂错误或有特殊处理要求的文件,仍需要通过用户交互来进行手工修复。文章在检查文件错误的基础上,提出了STL错误的手工修复方法,并开发了相应软件,通过实例验证了手工修复的必要性和有效性。     

装配机器人位姿误差分析

本文运用微分平移和微分回转变换概念,按照概率方法分析机器人关节误差对装配机器人位姿误差的影响。给出了计算最大位姿误差的关系式和手部位姿误差的模型。     

无线传感器网络时间同步概率误差研究*

研究WSNTS(无线传感器网络时间同步)误差,旨在分析影响WSNTS误差的因素,揭示WSNTS误差的分布规律。在分析了传统的NTP时间同步策略的基础上建立了WSNTS误差的数学模型,给出了单跳WSNTS误差分布规律（正态分布）,同时还给出了多跳WSNTS误差的随机过程模型及其均值和方差,并给出了多跳WSNTS误差的上、下限曲线。仿真实验证明这些结果是正确的。