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经典测量理论条件下强化子分数的方法
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作者 刘育明 《教育测量与评价》 2021年第5期3-10,共8页
在一些教育和心理测量中,除了报告给考生一个总分,教育考试机构通常还向考生报告两个或多个子分数,为考生提供掌握不同内容的能力强弱的诊断性信息,便于考生和教师进行有针对性的学习和教学。但是在教育和心理测验中,子测验的项目一般较... 在一些教育和心理测量中,除了报告给考生一个总分,教育考试机构通常还向考生报告两个或多个子分数,为考生提供掌握不同内容的能力强弱的诊断性信息,便于考生和教师进行有针对性的学习和教学。但是在教育和心理测验中,子测验的项目一般较少,同时各个子测验分数之间、子测验分数与测验总分之间的相关又比较高,因而子测验的信度一般比较低。由此,教育测量学家们提出用同一个测验里的其他子测验的分数或者总分的信息来提高子分数信度的方法,这就是强化子分数。本文介绍Haberman以经典测量理论为基础提出的强化子分数的基本概念,运用模拟数据和R函数介绍强化子分数的方法,包括根据子测验观察分、总分和强化子分数估计子分数的平均误方差减少比、子分数增值,以及强化子分数测量标准误。 展开更多
关键词 经典测量理论 强化子分数 RStudio函数 分数的信度 平均方差减少比 分数增值 强化子分数测量标准
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Stability of finite difference numerical simulations of acoustic logging-while-drilling with different perfectly matched layer schemes 被引量:3
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作者 王华 陶果 +2 位作者 尚学峰 方鑫定 Daniel R Burns 《Applied Geophysics》 SCIE CSCD 2013年第4期384-396,510,511,共15页
In acoustic logging-while-drilling (ALWD) finite difference in time domain (FDTD) simulations, large drill collar occupies, most of the fluid-filled borehole and divides the borehole fluid into two thin fluid colu... In acoustic logging-while-drilling (ALWD) finite difference in time domain (FDTD) simulations, large drill collar occupies, most of the fluid-filled borehole and divides the borehole fluid into two thin fluid columns (radius -27 mm). Fine grids and large computational models are required to model the thin fluid region between the tool and the formation. As a result, small time step and more iterations are needed, which increases the cumulative numerical error. Furthermore, due to high impedance contrast between the drill collar and fluid in the borehole (the difference is 〉30 times), the stability and efficiency of the perfectly matched layer (PML) scheme is critical to simulate complicated wave modes accurately. In this paper, we compared four different PML implementations in a staggered grid finite difference in time domain (FDTD) in the ALWD simulation, including field-splitting PML (SPML), multiaxial PML(M- PML), non-splitting PML (NPML), and complex frequency-shifted PML (CFS-PML). The comparison indicated that NPML and CFS-PML can absorb the guided wave reflection from the computational boundaries more efficiently than SPML and M-PML. For large simulation time, SPML, M-PML, and NPML are numerically unstable. However, the stability of M-PML can be improved further to some extent. Based on the analysis, we proposed that the CFS-PML method is used in FDTD to eliminate the numerical instability and to improve the efficiency of absorption in the PML layers for LWD modeling. The optimal values of CFS-PML parameters in the LWD simulation were investigated based on thousands of 3D simulations. For typical LWD cases, the best maximum value of the quadratic damping profile was obtained using one do. The optimal parameter space for the maximum value of the linear frequency-shifted factor (a0) and the scaling factor (β0) depended on the thickness of the PML layer. For typical formations, if the PML thickness is 10 grid points, the global error can be reduced to 〈1% using the optimal PML parameters, and the error will decrease as the PML thickness increases. 展开更多
关键词 PML schemes FD simulation LWD acoustic
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Calculation of saturation in carbonate reservoirs based on electrical efficiency 被引量:2
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作者 李雄炎 秦瑞宝 +1 位作者 刘春成 毛志强 《Applied Geophysics》 SCIE CSCD 2014年第2期215-222,254,共9页
We derived an equation for saturation in carbonate reservoirs based on the electrical efficiency model in the case of lacking core data. Owing to the complex pore structure and strong heterogeneity in carbonate reserv... We derived an equation for saturation in carbonate reservoirs based on the electrical efficiency model in the case of lacking core data. Owing to the complex pore structure and strong heterogeneity in carbonate reservoirs, the relation between electrical efficiency and water porosity is either complex or linear. We proposed an electrical efficiency equation that accounts for the relation between electrical efficiency and water porosity. We also proposed a power-law relation between electrical efficiency and deep-formation resistivity and analyzed the factors controlling the error in the water saturation computations. We concluded that the calculation accuracy of the electrical efficiency is critical to the application of the saturation equation. The saturation equation was applied to the carbonate reservoirs of three wells in Iraq and Indonesia. For relative rock electrical efficiency error below 0.1, the water saturation absolute error is also below 0.1. Therefore, we infer that the proposed saturation equation generally satisfies the evaluation criteria for carbonate reservoirs. 展开更多
关键词 Rock electrical efficiency CARBONATE SATURATION functional relationship error analysis
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测风记录定量诊断方法的研究——等差数列的利用
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作者 凌非 《成都信息工程学院学报》 2001年第1期21-24,共4页
测风记录的误读 ,是由分数误及整数误组成。根据基础理论 ,采用定量诊断方法来分析并纠正其误。结果表明 。
关键词 等差数列 测风记录 分数误 整数
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Design of the Testing System for Jet Elements
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作者 姚晓先 莫波 李亨标 《Journal of Beijing Institute of Technology》 EI CAS 2002年第3期225-228,共4页
To analyze the errors of processing data, the testing principle for jet elements is introduced and the property of testing system is theoretically and experimentally studied. On the basis of the above, the method of p... To analyze the errors of processing data, the testing principle for jet elements is introduced and the property of testing system is theoretically and experimentally studied. On the basis of the above, the method of processing data is presented and the error formulae, which are the functions of the testing system property, are derived. Finally, the methods of reducing the errors are provided. The measured results are in correspondence with the theoretical conclusion. 展开更多
关键词 jet elements error analysis data processing testing method
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Data Analysis and Modeling of Fiber Optic Gyroscope Drift 被引量:16
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作者 缪玲娟 张方生 +1 位作者 沈军 刘伟 《Journal of Beijing Institute of Technology》 EI CAS 2002年第1期50-55,共6页
A data gathering system is designed for the interferometric fiber optic gyroscope (IFOG) of land strapdown inertial system. IFOG is tested and the testing curve is given. The test data of IFOG are analyzed with Allan ... A data gathering system is designed for the interferometric fiber optic gyroscope (IFOG) of land strapdown inertial system. IFOG is tested and the testing curve is given. The test data of IFOG are analyzed with Allan variance method and each error coefficient is identified. Furthermore, a random drift error model for IFOG is built by the method of time series analysis. The conclusion provides supports for improving IFOG design and compensating for errors of IFOG in practice. 展开更多
关键词 fiber optic gyroscope random drift Allan variance MODELING
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A New Class of Biased Linear Estimators in Deficient-rank Linear Models 被引量:1
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作者 归庆明 段清堂 +1 位作者 周巧云 郭建锋 《Chinese Quarterly Journal of Mathematics》 CSCD 2001年第1期71-78,共8页
In this paper, we define a new class of biased linear estimators of the vector of unknown parameters in the deficient_rank linear model based on the spectral decomposition expression of the best linear minimun bias es... In this paper, we define a new class of biased linear estimators of the vector of unknown parameters in the deficient_rank linear model based on the spectral decomposition expression of the best linear minimun bias estimator. Some important properties are discussed. By appropriate choices of bias parameters, we construct many interested and useful biased linear estimators, which are the extension of ordinary biased linear estimators in the full_rank linear model to the deficient_rank linear model. At last, we give a numerical example in geodetic adjustment. 展开更多
关键词 deficient_rank model best linear minimum bias estimator generalized principal components estimator mean squared error condition number
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Rice condition numbers of QR and Cholesky factorizations
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作者 李新秀 聂小兵 《Journal of Southeast University(English Edition)》 EI CAS 2004年第1期130-134,共5页
A condition number is an amplification coefficient due to errors in computing. Thus the theory of condition numbers plays an important role in error analysis. In this paper, following the approach of Rice, condition n... A condition number is an amplification coefficient due to errors in computing. Thus the theory of condition numbers plays an important role in error analysis. In this paper, following the approach of Rice, condition numbers are defined for factors of some matrix factorizations such as the Cholesky factorization of a symmetric positive definite matrix and QR factorization of a general matrix. The condition numbers are derived by a technique of analytic expansion of the factor dependent on one parameter and matrix-vector equation. Condition numbers of the Cholesky and QR factors are different from the ones previously introduced by other authors, but similar to Chang's results. In Cholesky factorization, corresponding with the condition number of the factor matrix L , K _L is a low bound of Stewart's condition number K . 展开更多
关键词 Rice condition number Cholesky factorization QR decomposition
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3-D fracture network dynamic simulation based on error analysis in rock mass of dam foundation 被引量:4
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作者 ZHONG Deng-hua WU Han +2 位作者 WU Bin-ping ZHANG Yi-chi YUE Pan 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第4期919-935,共17页
Accurate 3-D fracture network model for rock mass in dam foundation is of vital importance for stability,grouting and seepage analysis of dam foundation.With the aim of reducing deviation between fracture network mode... Accurate 3-D fracture network model for rock mass in dam foundation is of vital importance for stability,grouting and seepage analysis of dam foundation.With the aim of reducing deviation between fracture network model and measured data,a 3-D fracture network dynamic modeling method based on error analysis was proposed.Firstly,errors of four fracture volume density estimation methods(proposed by ODA,KULATILAKE,MAULDON,and SONG)and that of four fracture size estimation methods(proposed by EINSTEIN,SONG and TONON)were respectively compared,and the optimal methods were determined.Additionally,error index representing the deviation between fracture network model and measured data was established with integrated use of fractal dimension and relative absolute error(RAE).On this basis,the downhill simplex method was used to build the dynamic modeling method,which takes the minimum of error index as objective function and dynamically adjusts the fracture density and size parameters to correct the error index.Finally,the 3-D fracture network model could be obtained which meets the requirements.The proposed method was applied for 3-D fractures simulation in Miao Wei hydropower project in China for feasibility verification and the error index reduced from 2.618 to 0.337. 展开更多
关键词 rock mass of dam foundation 3-D fracture network dynamic simulation fractal dimension error analysis relative absolute error(RAE) downhill simplex method
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Geometric Approximation Technique for Minimum Zone Sphericity Error 被引量:1
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作者 何改云 王太勇 +1 位作者 秦旭达 郭晓军 《Transactions of Tianjin University》 EI CAS 2005年第4期274-277,共4页
The mathematical modeling for evaluation of the sphericity error is proposed with minimum radial separation center. To obtain the minimum sphericity error from the form data, a geometric approximation technique was de... The mathematical modeling for evaluation of the sphericity error is proposed with minimum radial separation center. To obtain the minimum sphericity error from the form data, a geometric approximation technique was devised. The technique regarded the least square sphere center as the initial center of the concentric spheres containing all measurement points, and then the center was moved gradually to reduce the radial separation till the minimum radial separation center was got where the constructed concentric spheres conformed to the minimum zone condition. The method was modeled firstly, then the geometric approximation process was analyzed, and finally,the software for data processing was programmed. As evaluation example, five steel balls were measured and the measurement data were processed with the developed program. The average iteration times of the approximation technique is 4.2, and on average the obtained sphericity error is 0. 529μm smaller than the least square solution,with accuracy increased by 7. 696%. 展开更多
关键词 sphericity error minimum zone condition~ data processing form error evaluation
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Improved Cotes Formula and Error Analysis 被引量:1
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作者 DU Yue-peng XIAO Ze-chang 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第3期458-461,共4页
The truncation error of improved Cotes formula is presented in this paper. It also displays an analysis on convergence order of improved Cotes formula. Examples of numerical calculation is given in the end.
关键词 numerical integration algebraic accuracy truncation error convergence order
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Quantifying the attribution of model bias in simulating summer hot days in China with IAP AGCM 4.1 被引量:4
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作者 LIN Zhao-Hui YU Zheng +1 位作者 ZHANG He WU Cheng-Lai 《Atmospheric and Oceanic Science Letters》 CSCD 2016年第6期436-442,共7页
Using lAP AGCM simulation results for the period 1961-2005, summer hot days in China were calculated and then compared with observations. Generally, the spatial pattern of hot days is reasonably reproduced, with more ... Using lAP AGCM simulation results for the period 1961-2005, summer hot days in China were calculated and then compared with observations. Generally, the spatial pattern of hot days is reasonably reproduced, with more hot days found in northern China, the Yangtze and Huaihe River basin, the Chuan-Yu region, and southern Xinjiang. However, the model tends to overestimate the number of hot days in the above-mentioned regions, particularly in the Yangtze and Huaihe River basin where the simulated summer-mean hot days is 13 days more than observed when averaged over the whole region, and the maximum overestimation of hot days can reach 23 days in the region. Analysis of the probability distribution of daily maximum temperature (Trnax) suggests that the warm bias in the model-simulated Tmax contributes largely to the overestimation of hot days in the model. Furthermore, the discrepancy in the simulated variance of the Tmax distribution also plays a non- negligible role in the overestimation of hot days. Indeed, the latter can even account for 22% of the total bias of simulated hot days in August in the Yangtze and Huaihe River basin. The quantification of model bias from the mean value and variability can provide more information for further model improvement. 展开更多
关键词 Hot days variance inprobability distribution bias attribution modelevaluation IAP AGCM
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The Convergence of 1-Periodic Branched Continued Fraction of the Special Form in Parabolic Regions
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作者 Dmytro I. Bodnar Mariia M. Bubniak 《Journal of Mathematics and System Science》 2014年第4期269-274,共6页
Branched continued fractions are one of the multidimensional generalization of the continued fractions. Branched continued fractions with not equivalent variables are an analog of the regular C-fractions for multiple ... Branched continued fractions are one of the multidimensional generalization of the continued fractions. Branched continued fractions with not equivalent variables are an analog of the regular C-fractions for multiple power series. We consider 1-periodic branched continued fraction of the special form which is an analog fraction with not equivalent variables if the values of that variables are fixed. We establish an analog of the parabola theorem for that fraction and estimate truncation error bounds for that fractions at some restrictions. We also propose to use weight coefficients for obtaining different parabolic regions for the same fraction without any additional restriction for first element. 展开更多
关键词 Continued fractions 1-periodic branched continued fraction of special form CONVERGENCE uniform convergence truncation error bounds.
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Study on fast calibration of a ULA's gain and phase error 被引量:3
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作者 ZHU Guang-ping SUN Hui ZHANG Ming-hui 《Journal of Marine Science and Application》 2007年第2期64-69,共6页
Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound so... Array calibration is important in engineering practice. In this paper, fast calibration methods for a ULA's gain and phase errors both in far and near fields are proposed. In the far field, using a single sound source without exact orientation, this method horizontally rotates the array exactly once, performs eigen value decomposition for the covariance matrix of received data, then computes the gain and phase error according to the formulas. In the near field, using the same single sound source, it is necessary to rotate the array horizontally at most three times, build equations according to geometric relations, then solve them. Using the formula proposed in this paper, spherical waves are modified into plane waves. Then eigen values decomposition is performed. These two calibration methods were shown to be valid by simulation and are fast, accurate and easy to use. Finally, an analysis of factors influencing estimation precision is given. 展开更多
关键词 ULA single sound source gain and phase error eigen values decomposition
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Prediction of early-stage hepatocellular carcinoma using Onco Scan chromosomal copy number aberration data 被引量:2
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作者 Ming-Chin Yu Chao-Wei Lee +5 位作者 Yun-Shien Lee Jang-Hau Lian Chia-Lung Tsai Yi-Ping Liu Chun-Hsing Wu Chi-Neu Tsai 《World Journal of Gastroenterology》 SCIE CAS 2017年第44期7818-7829,共12页
AIM To identify chromosomal copy number aberrations(CNAs) in early-stage hepatocellular carcinoma(HCC) and analyze whether they are correlated with patient prognosis.METHODS One hundred and twenty patients with early-... AIM To identify chromosomal copy number aberrations(CNAs) in early-stage hepatocellular carcinoma(HCC) and analyze whether they are correlated with patient prognosis.METHODS One hundred and twenty patients with early-stage HCC were enrolled in our study, with the collection of formalin fixed, paraffin-embedded(FFPE) specimens and clinicopathological data. Tumor areas were marked by certified pathologists on a hematoxylin and eosinstained slide, and cancer and adjacent non-cancerous tissues underwent extraction of DNA, which was analyzed with the Affymetrix Onco Scan platform to assess CNAs and loss of heterozygosity(LOH). Ten individuals with nonmalignant disease were used as the control group. Another cohort consisting of 40 patients with stage Ⅰ/Ⅱ HCC were enrolled to analyze gene expression and to correlate findings with the Onco Scan data.RESULTS Copy number amplifications occurred at chromosomes 1 q21.1-q44 and 8 q12.3-24.3 and deletions were found at 4 q13.1-q35.2, 8 p 23.2-21.1, 16 q23.3-24.3, and 17 p13.3-12, while LOH commonly occurred at 1 p32.3, 3 p21.31, 8 p23.2-21.1, 16 q22.1-24.3, and 17 p 13.3-11 in early-stage HCC. Using Cox regression analysis, we also found that a higher percentage of genome change(≥ 60%) was an independent factor for worse prognosis in early-stage HCC(P = 0.031). Among the 875 genes in the Onco Scan Gene Chip, six were independent predictors of worse disease-free survival, of which three were amplified(MYC, ELAC2, and SYK) and three were deleted(GAK, MECOM, and WRN). Further, patients with HCC who exhibited ≥ 3 CNAs involving these six genes have worse outcomes compared to those who had < 3 CNAs(P < 0.001). Similarly, Asian patients with stage I HCC from The Cancer Genome Atlas harboring CNAs with these genes were also predicted to have poorer outcomes.CONCLUSION Patients with early-stage HCC and increased genome change or CNAs involving MYC, ELAC2, SYK, GAK, MECOM, or WRN are at risk for poorer outcome after resection. 展开更多
关键词 Early-stage hepatocellular carcinoma Copy number aberration Prognosis Onco Scan Molecular inversion probe
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A New Multi-sensor Data Fusion Algorithm Based on EMD-MMSE 被引量:2
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作者 张琦 阙沛文 +1 位作者 陈天璐 黄晶 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第2期153-158,共6页
A new multi-sensor data fusion algorithm based on EMD-MMSE was proposed.Empirical mode decomposition(EMD)is used to extract the noise of every time series for estimating the variance of the noise.Then minimum mean squ... A new multi-sensor data fusion algorithm based on EMD-MMSE was proposed.Empirical mode decomposition(EMD)is used to extract the noise of every time series for estimating the variance of the noise.Then minimum mean square error(MMSE)estimator is used to calculate the weights of the corresponding series.Finally,the fused signal is the weighted addition of all these series.The experiments in lab testified the efficiency of this method.In addition,the comparison in fusion time and fusion results with existing fusion method based on wavelet and average technique shows the advantage of this method greatly. 展开更多
关键词 data fusion empirical mode decomposition (EMD) minimum mean square error (MMSE) multisensor system
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Error Analysis on Corrector Formula for Rectangular Rule 被引量:1
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作者 XIAO Ze-chang DU Yue-peng 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2008年第2期270-275,共6页
This paper presents truncation errors among Corrector Formula for left Rectangular rule and Corrector Formula for middle Rectangular rule respectively. It also displays an analysis on convergence order of compound cor... This paper presents truncation errors among Corrector Formula for left Rectangular rule and Corrector Formula for middle Rectangular rule respectively. It also displays an analysis on convergence order of compound corrector formulas for rectangular rule. Examples of numerical calculation have validated theoretical analysis. 展开更多
关键词 numerical integration algebraic accuracy corrector formula truncation error convergence order
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Two Unconditional Stable Schemes for Simulation of Heat Equation on Manifold Using DEC
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作者 谢正 《Communications in Theoretical Physics》 SCIE CAS CSCD 2011年第2期321-324,共4页
To predict the heat diffusion in a given region over time, it is often necessary to find the numerical solution for heat equation. However, the computational domain of classical numerical methods are limited to fiat s... To predict the heat diffusion in a given region over time, it is often necessary to find the numerical solution for heat equation. However, the computational domain of classical numerical methods are limited to fiat spacetime. With the techniques of discrete differential calculus, we propose two unconditional stable numerical schemes for simulation heat equation on space manifold and time. The analysis of their stability and error is accomplished by the use of maximum principle. 展开更多
关键词 discrete exterior calculus discrete manifold heat equation
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Research on new software compensation method of static and quasi-static errors for precision motion controller
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作者 REN Kun FU Jian-zhong CHEN Zi-chen 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第12期1938-1943,共6页
To reduce mechanical vibrations induced by big errors compensation, a new software compensation method based on an improved digital differential analyzer (DDA) interpolator for static and quasi-static errors of machin... To reduce mechanical vibrations induced by big errors compensation, a new software compensation method based on an improved digital differential analyzer (DDA) interpolator for static and quasi-static errors of machine tools is proposed. Based on principle of traditional DDA interpolator, a DDA interpolator is divided into command generator and command analyzer. There are three types of errors, considering the difference of positions between compensation points and interpolation segments. According to the classification, errors are distributed evenly in data processing and compensated to certain interpolation segments in machining. On-line implementation results show that the proposed approach greatly improves positioning accuracy of computer numerical control (CNC) machine tools. 展开更多
关键词 Static and quasi-static errors Positioning and machining accuracy Digital differential analyzer (DDA) interoolator
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New Calibration Technology for Safety Valves of Utility Boiler 被引量:5
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作者 张传虎 刘琨 《Electricity》 2001年第4期44-49,共6页
Butterfly spring-relief valve, a crucial safety attachment of pressure vessel, is used to prevent pressuresystem from exceeding allowable limit value. Safe, expeditious and accurate calibration of safety valves is con... Butterfly spring-relief valve, a crucial safety attachment of pressure vessel, is used to prevent pressuresystem from exceeding allowable limit value. Safe, expeditious and accurate calibration of safety valves is consequentlyof vital importance to safe and economic operation of generating units. NSH CALIBRATOR could complete, not only theon-line performance and parameter tests of safety valves within two to five seconds with opening pressure of safetyvalves and steam medium pressure automatically recorded, but also could complete the on-line adjustment of safetyvalves verified unqualified. It saves energy consumption, decreases noise pollution and improves accuracy and efficiencyof safety valve calibration.[ 展开更多
关键词 on-line calibrator butterfly spring-relief valve error analysis data processing performancecharacteristics analysis
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