期刊文献+
共找到237篇文章
< 1 2 12 >
每页显示 20 50 100
Error Analysis of English Pronunciation Acquisition by Chinese Non-English Majors
1
作者 Lin Tao Haiying Liang 《Journal of Contemporary Educational Research》 2024年第2期34-47,共14页
Chinese non-English majors are a large group of English learners.In the process of English pronunciation acquisition,issues such as incomplete phonological knowledge,transfer of mother tongue,and overgeneralization,le... Chinese non-English majors are a large group of English learners.In the process of English pronunciation acquisition,issues such as incomplete phonological knowledge,transfer of mother tongue,and overgeneralization,lead to confusion of phonemes and stress,misunderstanding of syllable structure,and errors of assimilation,drop,and epenthesis.The accuracy of English pronunciation can only be improved by knowing both English and Chinese phonological systems,strengthening the teaching of English phonological knowledge,and adopting various phonological training activities. 展开更多
关键词 English pronunciation acquisition Non-English majors error analysis INVESTIGATION Second language acquisition
下载PDF
Error Analysis of A New Higher Order Boundary Element Method for A Uniform Flow Passing Cylinders
2
作者 SUN Shi-yan CUI Jie BAO Chao-ming 《China Ocean Engineering》 SCIE EI CSCD 2023年第3期369-377,共9页
A higher order boundary element method(HOBEM)is presented for inviscid flow passing cylinders in bounded or unbounded domain.The traditional boundary integral equation is established with respect to the velocity poten... A higher order boundary element method(HOBEM)is presented for inviscid flow passing cylinders in bounded or unbounded domain.The traditional boundary integral equation is established with respect to the velocity potential and its normal derivative.In present work,a new integral equation is derived for the tangential velocity.The boundary is discretized into higher order elements to ensure the continuity of slope at the element nodes.The velocity potential is also expanded with higher order shape functions,in which the unknown coefficients involve the tangential velocity.The expansion then ensures the continuities of the velocity and the slope of the boundary at element nodes.Through extensive comparison of the results for the analytical solution of cylinders,it is shown that the present HOBEM is much more accurate than the conventional BEM. 展开更多
关键词 higher order boundary element method(HOBEM) error analysis integral equations for potential and velocity cylinders
下载PDF
A Brief Study of Second Language Learning Strategies From the Perspective of Error Analysis
3
作者 PAN Yuhua 《Sino-US English Teaching》 2023年第10期385-391,共7页
Language teaching is not a one-way process.It interacts with language learning in an extremely intricate way.To improve language teaching,we need to take the process of language learning into account.This paper tries ... Language teaching is not a one-way process.It interacts with language learning in an extremely intricate way.To improve language teaching,we need to take the process of language learning into account.This paper tries to explore and understand what strategies the second language learners consciously or subconsciously adopt during their language learning process through the analyses of the linguistic errors they commit,so as to provide some insights into language teaching practice. 展开更多
关键词 second language acquisition error analysis learning strategies language teaching
下载PDF
Relationships between Terrain Features and Forecasting Errors of Surface Wind Speeds in a Mesoscale Numerical Weather Prediction Model
4
作者 Wenbo XUE Hui YU +1 位作者 Shengming TANG Wei HUANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第6期1161-1170,共10页
Numerical weather prediction(NWP)models have always presented large forecasting errors of surface wind speeds over regions with complex terrain.In this study,surface wind forecasts from an operational NWP model,the SM... Numerical weather prediction(NWP)models have always presented large forecasting errors of surface wind speeds over regions with complex terrain.In this study,surface wind forecasts from an operational NWP model,the SMS-WARR(Shanghai Meteorological Service-WRF ADAS Rapid Refresh System),are analyzed to quantitatively reveal the relationships between the forecasted surface wind speed errors and terrain features,with the intent of providing clues to better apply the NWP model to complex terrain regions.The terrain features are described by three parameters:the standard deviation of the model grid-scale orography,terrain height error of the model,and slope angle.The results show that the forecast bias has a unimodal distribution with a change in the standard deviation of orography.The minimum ME(the mean value of bias)is 1.2 m s^(-1) when the standard deviation is between 60 and 70 m.A positive correlation exists between bias and terrain height error,with the ME increasing by 10%−30%for every 200 m increase in terrain height error.The ME decreases by 65.6%when slope angle increases from(0.5°−1.5°)to larger than 3.5°for uphill winds but increases by 35.4%when the absolute value of slope angle increases from(0.5°−1.5°)to(2.5°−3.5°)for downhill winds.Several sensitivity experiments are carried out with a model output statistical(MOS)calibration model for surface wind speeds and ME(RMSE)has been reduced by 90%(30%)by introducing terrain parameters,demonstrating the value of this study. 展开更多
关键词 surface wind speed terrain features error analysis MOS calibration model
下载PDF
Convergence analysis for complementary-label learning with kernel ridge regression
5
作者 NIE Wei-lin WANG Cheng XIE Zhong-hua 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第3期533-544,共12页
Complementary-label learning(CLL)aims at finding a classifier via samples with complementary labels.Such data is considered to contain less information than ordinary-label samples.The transition matrix between the tru... Complementary-label learning(CLL)aims at finding a classifier via samples with complementary labels.Such data is considered to contain less information than ordinary-label samples.The transition matrix between the true label and the complementary label,and some loss functions have been developed to handle this problem.In this paper,we show that CLL can be transformed into ordinary classification under some mild conditions,which indicates that the complementary labels can supply enough information in most cases.As an example,an extensive misclassification error analysis was performed for the Kernel Ridge Regression(KRR)method applied to multiple complementary-label learning(MCLL),which demonstrates its superior performance compared to existing approaches. 展开更多
关键词 multiple complementary-label learning partial label learning error analysis reproducing kernel Hilbert spaces
下载PDF
Error Analysis and Compensation of Strapdown Inertial Navigation System 被引量:16
6
作者 刘勤 刘莉 祁载康 《Journal of Beijing Institute of Technology》 EI CAS 2002年第2期117-120,共4页
Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy... Based on error analysis, the influence of error sources on strapdown inertial navigation systems is discussed. And the maximum permissible component tolerances are established. In order to achieve the desired accuracy (defined by circular error probability), the types of appropriate sensors are chosen. The inertial measurement unit (IMU) is composed of those sensors. It is necessary to calibrate the sensors to obtain their error model coefficients of IMU. After calibration tests, the accuracy is calculated by uniform design method and it is proved that the accuracy of IMU is satisfied for the desired goal. 展开更多
关键词 error analysis strapdown inertial navigation system uniform design method calibration test
下载PDF
Instantaneous rotation speed measurement and error analysis for variable speed hydraulic system 被引量:1
7
作者 杨彬 谷立臣 +1 位作者 刘永 王平 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2015年第4期315-321,共7页
In order to monitor the working state of piston motor and measure its instantaneous rotation speed accurately, the measuring principle and method of instantaneous rotation speed based on industrial personal computer a... In order to monitor the working state of piston motor and measure its instantaneous rotation speed accurately, the measuring principle and method of instantaneous rotation speed based on industrial personal computer and data acquisition card are introduced, and the major error source, influence mechanism and processing method of data quantization error are dis- cussed. By means of hybrid programming approach of LabVIEW and MATLAB, the instantaneous rotation speed measurement system for the piston motor in variable speed hydraulic system is designed. The simulation and experimental results show that the designed instantaneous speed measurement system is feasible. Furthermore, the sampling frequency has an important influ- ence on the instantaneous rotation speed measurement of piston motor and higher sampling frequency can lower quantization er- ror and improve measurement accuracy. 展开更多
关键词 variable speed hydraulic system instantaneous rotation speed measurement error analysis hybrid programming
下载PDF
Error Analysis and Error Correction in English Learning
8
作者 罗赟梅 《英语广场(学术研究)》 2012年第2期86-88,共3页
As a field in applied linguistics, error analysis is not only an instrument for language acquisition research but also an auxiliary tool for language teaching. It plays a significant role both in exploring the learnin... As a field in applied linguistics, error analysis is not only an instrument for language acquisition research but also an auxiliary tool for language teaching. It plays a significant role both in exploring the learning rules and improving the teaching of foreign languages. With this information, teachers could adjust their teaching plan and make their teaching more effective. In this paper I present some common errors that my students make in their learning process. Based on these, a further elaboration on how to correct errors, including the attitudes to them, the integrative principles, the concrete methods and techniques for error correction is discussed as well. 展开更多
关键词 errorS CAUSES error analysis CORRECTION
下载PDF
Chebyshev Fitting Way and Error Analysis for Propeller Atlas across Four Quadrants 被引量:20
9
作者 LI Dian-pu, WANG Zong-yi, CHI Hai-hong College of Automation , Harbin Engineering University, Harbin 150001, China 《Journal of Marine Science and Application》 2002年第1期52-59,共8页
A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomial fitting results and its error analysis are given. Because it’s difficult generally to get a propel... A Chebyshev fitting way for a propeller atlas across four quadrants is discussed. As an example, Chebyshev polynomial fitting results and its error analysis are given. Because it’s difficult generally to get a propeller atlas across four quadrants, a way is used to construct an alternative with higher accuracy based on the properties. As an application example, an alternative for the propeller property of a Deep Submergence Vehicle across four quadrants is given practically and a simulation model of the four quadrants propeller for dynamic condition is set up. The model lays a foundation for DSV full operating-condition movement simulation. A lot of simulation work shows that the results are very close to the practical data and, therefore, are effective. 展开更多
关键词 PROPELLER four quadrants property dynamic simulation ATLAS Chebyshev polynomial DSV alternative property error analysis
下载PDF
Analysis of Error for a Rotating Strap-down Inertial Navigation System with Fibro Gyro 被引量:6
10
作者 奔粤阳 柴永利 +1 位作者 高伟 孙枫 《Journal of Marine Science and Application》 2010年第4期419-424,共6页
The error equation of a rotating inertial navigation system was introduced. The effect of the system's main error source (constant drift of gyro and zero bias of accelerometer) under rotating conditions for the sy... The error equation of a rotating inertial navigation system was introduced. The effect of the system's main error source (constant drift of gyro and zero bias of accelerometer) under rotating conditions for the system was analyzed. Validity of theoretical analysis was shown via simulation, and that provides a theoretical foundation for a rotating strap-down inertial navigation system during actual experimentation and application. 展开更多
关键词 fibro gyro rotating strap-down inertial navigation error analysis
下载PDF
Error Analysis of Three Degree-of-Freedom Changeable Parallel Measuring Mechanism 被引量:7
11
作者 CHENG Gang GE Shi-rong WANG Yong 《Journal of China University of Mining and Technology》 EI 2007年第1期101-104,共4页
A three degree-of-freedom (DOF) planar changeable parallel mechanism is designed by means of control of different drive parameters. This mechanism possesses the characteristics of two kinds of parallel mechanism. Base... A three degree-of-freedom (DOF) planar changeable parallel mechanism is designed by means of control of different drive parameters. This mechanism possesses the characteristics of two kinds of parallel mechanism. Based on its topologic structure, a coordinate system for position analysis is set-up and the forward kinematic solutions are analyzed. It was found that the parallel mechanism is partially decoupled. The relationship between original errors and position-stance error of moving platform is built according to the complete differential-coefficient theory. Then we present a special example with theory values and errors to evaluate the error model, and numerical error solutions are gained. The investigations concentrating on mechanism errors and actuator errors show that the mechanism errors have more influences on the position-stance of the moving platform. It is demonstrated that improving manufacturing and assembly techniques can greatly reduce the moving platform error. The small change in position-stance error in different kinematic positions proves that the error-compensation of software can improve considerably the precision of parallel mechanism. 展开更多
关键词 parallel mechanism changeable measuring mechanism kinematics forward analysis error model error analysis
下载PDF
An analysis on the error structure and mechanism of soil moisture and ocean salinity remotely sensed sea surface salinity products 被引量:3
12
作者 CHEN Jian ZHANG Ren +3 位作者 WANG Huizan AN Yuzhu WANG Luhua WANG Gongjie 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2014年第1期48-55,共8页
For the application of soil moisture and ocean salinity(SMOS) remotely sensed sea surface salinity(SSS) products,SMOS SSS global maps and error characteristics have been investigated based on quality control infor... For the application of soil moisture and ocean salinity(SMOS) remotely sensed sea surface salinity(SSS) products,SMOS SSS global maps and error characteristics have been investigated based on quality control information.The results show that the errors of SMOS SSS products are distributed zonally,i.e.,relatively small in the tropical oceans,but much greater in the southern oceans in the Southern Hemisphere(negative bias) and along the southern,northern and some other oceanic margins(positive or negative bias).The physical elements responsible for these errors include wind,temperature,and coastal terrain and so on.Errors in the southern oceans are due to the bias in an SSS retrieval algorithm caused by the coexisting high wind speed and low temperature; errors along the oceanic margins are due to the bias in a brightness temperature(TB) reconstruction caused by the high contrast between L-band emissivities from ice or land and from ocean; in addition,some other systematic errors are due to the bias in TB observation caused by a radio frequency interference and a radiometer receivers drift,etc.The findings will contribute to the scientific correction and appropriate application of the SMOS SSS products. 展开更多
关键词 soil moisture and ocean salinity SMOS remotely sensed sea surface salinity error analysis
下载PDF
Error Analysis of Adsorption Isotherm Models for Acid Dyes onto Bamboo Derived Activated Carbon 被引量:2
13
作者 L.S.Chan W.H.Cheung +1 位作者 S.J.Allen G.McKay 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2012年第3期535-542,共8页
High surface area activated carbons were produced by thermal activation of waste bamboo scaffolding with phosphoric acid.Single component equilibrium dye adsorption was conducted on the carbons produced and compared w... High surface area activated carbons were produced by thermal activation of waste bamboo scaffolding with phosphoric acid.Single component equilibrium dye adsorption was conducted on the carbons produced and compared with a commercially available carbon.Two acid dyes with different molecular sizes,namely Acid Yellow 117(AY117) and Acid Blue 25(AB25),were used to evaluate the adsorption capacity of the produced carbons.It was found that the dye with smaller molecular size,AB 25,was readily adsorbed onto the produced carbon,nearly three times higher than a commercially available carbon,while the larger size dye,AY117,showed little adsorption.The experimental data were analyzed using isotherm equations including Langmuir,Freundlich,Tempkin,Toth,Redlich-Peterson and Sips equations.The equilibrium data were then analyzed using five different non-linear error analysis methods. 展开更多
关键词 ADSORPTION activated carbon acid dye equilibrium isotherm error analysis BAMBOO
下载PDF
3-D fracture network dynamic simulation based on error analysis in rock mass of dam foundation 被引量:4
14
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
下载PDF
Attractive Multistep Reproducing Kernel Approach for Solving Stiffness Differential Systems of Ordinary Differential Equations and Some Error Analysis 被引量:1
15
作者 Radwan Abu-Gdairi Shatha Hasan +2 位作者 Shrideh Al-Omari Mohammad Al-Smadi Shaher Momani 《Computer Modeling in Engineering & Sciences》 SCIE EI 2022年第1期299-313,共15页
In this paper,an efficient multi-step scheme is presented based on reproducing kernel Hilbert space(RKHS)theory for solving ordinary stiff differential systems.The solution methodology depends on reproducing kernel fu... In this paper,an efficient multi-step scheme is presented based on reproducing kernel Hilbert space(RKHS)theory for solving ordinary stiff differential systems.The solution methodology depends on reproducing kernel functions to obtain analytic solutions in a uniform formfor a rapidly convergent series in the posed Sobolev space.Using the Gram-Schmidt orthogonality process,complete orthogonal essential functions are obtained in a compact field to encompass Fourier series expansion with the help of kernel properties reproduction.Consequently,by applying the standard RKHS method to each subinterval,approximate solutions that converge uniformly to the exact solutions are obtained.For this purpose,several numerical examples are tested to show proposed algorithm’s superiority,simplicity,and efficiency.The gained results indicate that themulti-step RKHSmethod is suitable for solving linear and nonlinear stiffness systems over an extensive duration and giving highly accurate outcomes. 展开更多
关键词 Multi-step approach reproducing kernel Hilbert space method stiffness system error analysis numerical solution
下载PDF
Convergence ball and error analysis of Ostrowski-Traub’s method 被引量:1
16
作者 BI Wei-hong WU Qing-biao REN Hong-min 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2010年第3期374-378,共5页
Under the hypotheses that the second-order and third-order derivatives of a function are bounded, an estimate of the radius of the convergence ball of Ostrowski-Traub's method is obtained. An error analysis is given ... Under the hypotheses that the second-order and third-order derivatives of a function are bounded, an estimate of the radius of the convergence ball of Ostrowski-Traub's method is obtained. An error analysis is given which matches the convergence order of the method. Finally, two examples are provided to show applications of our theorem. 展开更多
关键词 Ostrowski-Traub's method nonlinear equation convergence ball estimate of radius error analysis
下载PDF
Error Analysis of FLC Experimental Data at Warm/Hot Stamping Conditions 被引量:1
17
作者 ZHUANG Weimin ZHANG Mengxi CHEN Yanhong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第4期730-737,共8页
Forming limit curves(FLCs) are commonly used for evaluating the formability of sheet metals. However, it is difficult to obtain the FLCs with desirable accuracy by experiments due to that the friction effects are no... Forming limit curves(FLCs) are commonly used for evaluating the formability of sheet metals. However, it is difficult to obtain the FLCs with desirable accuracy by experiments due to that the friction effects are non-negligible under warm/hot stamping conditions. To investigate the experimental errors, experiments for obtaining the FLCs of the AA5754 are conducted at 250℃. Then, FE models are created and validated on the basis of experimental results. A number of FE simulations are carried out for FLC test-pieces and punches with different geometry configurations and varying friction coefficients between the test-piece and the punch. The errors for all the test conditions are predicted and analyzed. Particular attention of error analysis is paid to two special cases, namely, the biaxial FLC test and the uniaxial FLC test. The failure location and the variation of the error with respect to the friction coefficient are studied as well. The results obtained from the FLC tests and the above analyses show that, for the biaxial tension state, the friction coefficient should be controlled within 0.15 to avoid significant shifting of the necking location away from the center of the punch; for the uniaxial tension state, the friction coefficient should be controlled within 0.1 to guarantee the validity of the data collected from FLC tests. The conclusions summarized are beneficial for obtaining accurate FLCs under warm/hot stamping conditions. 展开更多
关键词 forming limit curve(FLC) error analysis warm/hot stamping finite element analysis
下载PDF
Error modeling and analysis of inclinometer based on digital accelerometer 被引量:1
18
作者 白渚铨 张晓明 刘俊 《Journal of Measurement Science and Instrumentation》 CAS 2013年第4期321-324,共4页
Measuring accuracy of inclinometer based on accelerometer is mainly influenced by the adopted accelerometer sensor.To improve the measuring accuracy of the inclinometer,the structure of the measuring system is given a... Measuring accuracy of inclinometer based on accelerometer is mainly influenced by the adopted accelerometer sensor.To improve the measuring accuracy of the inclinometer,the structure of the measuring system is given and measuring principle is analyzed,and the error model is established in this paper.Furthermore,the model is verified by simulation and experiment,which not only gives the smallest errors of the measured pitch and roll,but also lays foundation for sensor selection,error analysis and error compensation.The results show that the error model is of practical value. 展开更多
关键词 INCLINOMETER ACCELEROMETER error modeling error analysis
下载PDF
In-situ strain measurement and error analysis of arc welding with 2D digital image correlation 被引量:1
19
作者 Huang Honghao Hu Minghua +2 位作者 Xu Aijie Song Yulin Chen Huabin 《China Welding》 CAS 2022年第3期17-23,共7页
The deformation and residual stress generated by the welding process can seriously affect the use of components.As a result,it is very important to understand the evolution of stress and strain during the welding proc... The deformation and residual stress generated by the welding process can seriously affect the use of components.As a result,it is very important to understand the evolution of stress and strain during the welding process.The strain measurement method based on digital image correlation(DIC)is an excellent method to detect welding strain and residual stress.The out-of-plane translation and out-of-plane rotation introduce errors to the two-dimensional DIC.In this paper,the causes of errors are analyzed theoretically,and the formulas of errors caused by the out-of-plane displacement and the out-of-plane rotation are derived.The out-of-plane translation experiment and the out-of-plane rotation experiment were carried out to verify the theory,and the experimental results are consistent with the theoretical analysis results.The error caused by the out-of-plane translation can be reduced by increasing the object distance;the error caused by the out-of-plane rotation is greatly affected by the rotation angle. 展开更多
关键词 arc welding digital image correlation strain measurement error analysis
下载PDF
NOVEL METHOD FOR ERROR ANALYSIS AND SELF-CALIBRATION OF LASER TRACKING MIRROR MECHANISM 被引量:2
20
作者 OUYANG Jianfei LIU Wanli +2 位作者 QU Xinghua YAN Yonggang WANG Zhankui 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2008年第4期1-6,共6页
Laser tracking system (LTS) is an advanced device for large size 3D coordinates measuring with the advantages of broad range, high speed and high accuracy. However, its measuring accuracy is highly dominated by the ... Laser tracking system (LTS) is an advanced device for large size 3D coordinates measuring with the advantages of broad range, high speed and high accuracy. However, its measuring accuracy is highly dominated by the geometric errors of the tracking mirror mechanism. Proper calibration of LTS is essential prior to the use of it for metrology. A kinematics model that describes not only the motion but also the geometric variations of LTS is developed. Through error analysis of the proposed model, it is claimed that gimbals axis misalignments and tracking mirror center off-set are the key contributors to measuring errors of LTS. A self-calibration method is presented of calibrating LTS with planar constraints. Various calibration strategies utilizing single-plane and multiple-plane constraints are proposed for different situations. For each calibration strategy, issues about the error parameter estimation of LTS are exploded to find out in which conditions these parameters can be uniquely estimated. Moreover, these conditions reveal the applicability of the planar constraints to LTS self-calibration. Intensive studies have been made to check validity of the theoretical results. The results show that the measuring accuracy of LTS has increased by 5 times since this technique for calibration is used. 展开更多
关键词 Laser tracking error analysis Self-calibration Planar constraints Tracking mirror
下载PDF
上一页 1 2 12 下一页 到第
使用帮助 返回顶部