期刊文献+
共找到6,748篇文章
< 1 2 250 >
每页显示 20 50 100
The Analysis of Gauss Radial Basis Functions and Its Application in Locating Olivine on the Moon
1
作者 SONG Shicang SONG Xiaoyuan SONG Shuhan 《应用数学》 北大核心 2026年第1期173-181,共9页
Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the m... Gauss radial basis functions(GRBF)are frequently employed in data fitting and machine learning.Their linear independence property can theoretically guarantee the avoidance of data redundancy.In this paper,one of the main contributions is proving this property using linear algebra instead of profound knowledge.This makes it easy to read and understand this fundamental fact.The proof of linear independence of a set of Gauss functions relies on the constructing method for one-dimensional space and on the deducing method for higher dimensions.Additionally,under the condition of preserving the same moments between the original function and interpolating function,both the interpolating existence and uniqueness are proven for GRBF in one-dimensional space.The final work demonstrates the application of the GRBF method to locate lunar olivine.By combining preprocessed data using GRBF with the removing envelope curve method,a program is created to find the position of lunar olivine based on spectrum data,and the numerical experiment shows that it is an effective scheme. 展开更多
关键词 Gauss function Radial basis function Machine learning Lunar olivine locating Data fitting
在线阅读 下载PDF
DIGITAL PWM OF AC-AC MATRIX CONVERTER BASED ON OUTPUT-VOLTAGE ERROR FUNCTION 被引量:1
2
作者 葛红娟 穆新华 +1 位作者 张绍 周波 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2005年第4期307-311,共5页
Based on the output-voltage error function, a novel time discrete modulation technique is proposed for matrix converters (MCs) and time-discrete difference equations of a MC circuit are derived. Switch states of MC ... Based on the output-voltage error function, a novel time discrete modulation technique is proposed for matrix converters (MCs) and time-discrete difference equations of a MC circuit are derived. Switch states of MC are obtained when the output voltage error function is minimized, thus the optimum combination of switch states is derived for the closed-loop control of MC. Meanwhile, advantages of the least calculation workload, the simple process, and the convenient for implementation are brought while switch states are described as space vectors in the α-β coordination system. Simulation and experimental results demonstrate the validity of the time-discrete modulation technique and the feasibility of the control approach. 展开更多
关键词 matrix converter time-discrete modulation error function switch state
在线阅读 下载PDF
Function fitting for modeling seasonal normalized difference vegetation index time series and early forecasting of soybean yield 被引量:2
3
作者 Alexey Stepanov Konstantin Dubrovin Aleksei Sorokin 《The Crop Journal》 SCIE CSCD 2022年第5期1452-1459,共8页
Forecasting crop yields based on remote sensing data is one of the most important tasks in agriculture.Soybean is the main crop in the Russian Far East.It is desirable to forecast soybean yield as early as possible wh... Forecasting crop yields based on remote sensing data is one of the most important tasks in agriculture.Soybean is the main crop in the Russian Far East.It is desirable to forecast soybean yield as early as possible while maintaining high accuracy.This study aimed to investigate seasonal time series of the normalized difference vegetation index(NDVI) to achieve early forecasting of soybean yield.This research used data from the Moderate Resolution Image Spectroradiometer(MODIS),an arable-land mask obtained from the VEGA-Science web service,and soybean yield data for 2008-2017 for the Jewish Autonomous Region(JAR) districts.Four approximating functions were fitted to model the NDVI time series:Gaussian,double logistic(DL),and quadratic and cubic polynomials.In the period from calendar weeks 22-42(end of May to mid-October),averaged over two districts,the model using the DL function showed the highest accuracy(mean absolute percentage error-4.0%,root mean square error(RMSE)-0.029,P <0.01).The yield forecast accuracy of prediction in the period of weeks 25-30 in JAR municipalities using the parameters of the Gaussian function was higher(P <0.05) than that using the other functions.The mean forecast error for the Gaussian function was 14.9% in week 25(RMSE was0.21 t ha) and 5.1%-12.9% in weeks 26-30(RMSE varied from 0.06 to 0.15 t ha) according to the2013-2017 data.In weeks 31-32,the error was 5.0%-5.4%(RMSE was 0.07 t ha) using the Gaussian parameters and 7.4%-7.7%(RMSE was 0.09-0.11 t ha) for the DL function.When the method was applied to municipal districts of other soy-producing regions of the Russian Far East.RMSE was0.14-0.32 t hain weeks 25-26 and did not exceed 0.20 t hain subsequent weeks. 展开更多
关键词 NDVI function fitting Early prediction YIELD SOYBEAN
在线阅读 下载PDF
Probability density function and estimation for error of digitized map coordinates in GIS 被引量:1
4
作者 童小华 刘大杰 《Journal of Central South University of Technology》 SCIE EI CAS 2004年第1期69-74,共6页
Traditionally, it is widely accepted that measurement error usually obeys the normal distribution. However, in this paper a new idea is proposed that the error in digitized data which is a major derived data source in... Traditionally, it is widely accepted that measurement error usually obeys the normal distribution. However, in this paper a new idea is proposed that the error in digitized data which is a major derived data source in GIS does not obey the normal distribution but the p-norm distribution with a determinate parameter. Assuming that the error is random and has the same statistical properties, the probability density function of the normal distribution, Laplace distribution and p-norm distribution are derived based on the arithmetic mean axiom, median axiom and p-median axiom, which means that the normal distribution is only one of these distributions but not the least one. Based on this ideal distribution fitness tests such as Skewness and Kurtosis coefficient test, Pearson chi-square chi(2) test and Kolmogorov test for digitized data are conducted. The results show that the error in map digitization obeys the p-norm distribution whose parameter is close to 1.60. A least p-norm estimation and the least square estimation of digitized data are further analyzed, showing that the least p-norm adjustment is better than the least square adjustment for digitized data processing in GIS. 展开更多
关键词 probability density function distribution fitness test least p-norm estimation
在线阅读 下载PDF
The Error Compensation of Inclinometer Based on Polynomial Fitting 被引量:1
5
作者 Xiaofei Zhang Dong Li 《Advances in Aerospace Science and Technology》 2021年第1期1-8,共8页
In order to</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> reduce the influence of nonlinear </span><span... In order to</span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> reduce the influence of nonlinear </span><span style="font-family:Verdana;">characteristic</span><span style="font-family:Verdana;"> and temperature on the measuring accuracy of </span><span style="font-family:Verdana;">inclinometer</span><span style="font-family:Verdana;">, the application of </span><span style="font-family:Verdana;">polynomial</span><span style="font-family:Verdana;"> fitting principle to compensate </span><span style="font-family:Verdana;">the</span><span style="font-family:Verdana;"> measuring error of </span><span style="font-family:Verdana;">inclinometer</span><span style="font-family:Verdana;"> is studied. According to the analysis of the experimental data of inclinometer, a polynomial model of the nonlinear error and the measured value is constructed, and then the relation between the coefficient of the polynomial model and the temperature is obtained by fitting, and </span><span style="font-family:Verdana;">finally</span><span style="font-family:Verdana;"> the function of the measurement error of inclinometer on the measured inclination and temperature is obtained. The results show that this method is feasible and effective, which can not only reduce the influence of </span><span style="font-family:Verdana;">temperature,</span><span style="font-family:Verdana;"> but also correct its nonlinear error. 展开更多
关键词 Polynomial fitting INCLINOMETER error Compensation
在线阅读 下载PDF
A Two-step Estimation Method of Troposphere Delay with Consideration of Mapping Function Errors 被引量:13
6
作者 Haopeng FAN Zhongmiao SUN +1 位作者 Liping ZHANG Xiaogang LIU 《Journal of Geodesy and Geoinformation Science》 2020年第1期76-84,共9页
Mapping function errors are usually not taken into consideration, when space geodetic data observed by VLBI, GNSS and some other techniques are utilized to estimate troposphere delay, which could, however, probably br... Mapping function errors are usually not taken into consideration, when space geodetic data observed by VLBI, GNSS and some other techniques are utilized to estimate troposphere delay, which could, however, probably bring non-ignorable errors to solutions. After analyzing the variation of mapping function errors with elevation angles based on several-year meteorological data, this paper constructed a model of this error and then proposed a two-step estimation method of troposphere delay with consideration of mapping function errors. The experimental results indicate that the method put forward by this paper could reduce the slant path delay residuals efficiently and improve the estimation accuracy of wet tropospheric delay to some extent. 展开更多
关键词 TROPOSPHERIC DELAY mapping function errorS Very Long BASELINE Interferometry parameter weighted adjustment European CENTRE for Medium-Range Weather Forecasts
在线阅读 下载PDF
Large Scattered Data Fitting Based on Radial Basis Functions 被引量:2
7
作者 FENG Ren-zhong XU Liang 《Computer Aided Drafting,Design and Manufacturing》 2007年第1期66-72,共7页
Solving large radial basis function (RBF) interpolation problem with non-customized methods is computationally expensive and the matrices that occur are typically badly conditioned. In order to avoid these difficult... Solving large radial basis function (RBF) interpolation problem with non-customized methods is computationally expensive and the matrices that occur are typically badly conditioned. In order to avoid these difficulties, we present a fitting based on radial basis functions satisfying side conditions by least squares, although compared with interpolation the method loses some accuracy, it reduces the computational cost largely. Since the fitting accuracy and the non-singularity of coefficient matrix in normal equation are relevant to the uniformity of chosen centers of the fitted RBE we present a choice method of uniform centers. Numerical results confirm the fitting efficiency. 展开更多
关键词 scattered data radial basis functions interpolation least squares fitting uniform centers
在线阅读 下载PDF
The Application of Multiquadric Function Fitting to Borehole Strain Time Series Data Processing 被引量:1
8
作者 Peng Zhao Zhang Lei +1 位作者 Chen Zhiyao Lv Pingji 《Earthquake Research in China》 CSCD 2017年第2期239-246,共8页
Based on the existing continuous borehole strain observation,the multiquadric function fitting method was used to deal with time series data. The impact of difference kernel function parameters was discussed to obtain... Based on the existing continuous borehole strain observation,the multiquadric function fitting method was used to deal with time series data. The impact of difference kernel function parameters was discussed to obtain a valuable fitting result,from which the physical connotation of the original data and its possible applications were analyzed.Meanwhile,a brief comparison was made between the results of multiquadric function fitting and polynomial fitting. 展开更多
关键词 Multiquadric function fitting Kernel function Borehole strain time series
在线阅读 下载PDF
Generalized gap functions and error bounds for generalized variational inequalities
9
作者 胡艳红 宋文 Xie-ping DING 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2009年第3期313-321,共9页
We consider some classes of generalized gap functions for two kinds of generalized variational inequality problems. We obtain error bounds for the underlying variational inequalities using the generalized gap function... We consider some classes of generalized gap functions for two kinds of generalized variational inequality problems. We obtain error bounds for the underlying variational inequalities using the generalized gap functions under the condition that the involved mapping F is g-strongly monotone with respect to the solution, but not necessarily continuous differentiable, even not locally Lipschitz. 展开更多
关键词 variational inequality gap functions error bounds
在线阅读 下载PDF
Error Bound for the Generalized Complementarity Problem with Analytic Functions
10
作者 Hong-Chun Sun School of Sciences, Linyi University, Linyi 276005, PRC 《International Journal of Automation and computing》 EI 2012年第3期288-291,共4页
In this paper, we consider the global error bound for the generalized complementarity problem (GCP) with analytic functions. Based on the new technique, we establish computable global error bound under milder conditio... In this paper, we consider the global error bound for the generalized complementarity problem (GCP) with analytic functions. Based on the new technique, we establish computable global error bound under milder conditions, which refines the previously known results. 展开更多
关键词 Generalized complementarity problem (GCP) error bound analytic functions R0-function Lipschitz continuity.
原文传递
THE DISPLACEMENT FUNCTION OF QUASI-CONFORMING ELEMENT AND ITS NODE ERROR
11
作者 HE Dong-sheng(何东升) +1 位作者 TANG Li-min(唐立民) 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2002年第2期127-137,共11页
Based on the strain formulation of the quasi-conforming finite element, displacement functions are constructed which have definite physical meaning, and a conclusion can be obtained that the coefficients of the consta... Based on the strain formulation of the quasi-conforming finite element, displacement functions are constructed which have definite physical meaning, and a conclusion can be obtained that the coefficients of the constant and the linear strain are uniquely determined, and the quasi-conforming finite element method is convergent to constant strain. There are different methods for constructing the rigid displacement items, and different methods correspond to different order node errors, and this is different from ordinary displacement method finite element. 展开更多
关键词 quasi-conforming element displacement function error analysis finite element method 9-parameter triangular plate element
在线阅读 下载PDF
RESIDUAL A POSTERIORI ERROR ESTIMATE TWO-GRID METHODS FOR THE STEADY (NAVIER-STOKES) EQUATION WITH STREAM FUNCTION FORM
12
作者 任春风 马逸尘 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第5期546-559,共14页
Residual based on a posteriori error estimates for conforming finite element solutions of incompressible Navier-Stokes equations with stream function form which were computed with seven recently proposed two-level met... Residual based on a posteriori error estimates for conforming finite element solutions of incompressible Navier-Stokes equations with stream function form which were computed with seven recently proposed two-level method were derived. The posteriori error estimates contained additional terms in comparison to the error estimates for the solution obtained by the standard finite element method. The importance of these additional terms in the error estimates was investigated by studying their asymptotic behavior. For optimal scaled meshes, these bounds are not of higher order than of convergence of discrete solution. 展开更多
关键词 two-level method Navier-Stokes equation residual a posteriori error estimate finite element method stream function form
在线阅读 下载PDF
Application of Complementary Error Function to the Transition Zone of Myopic Ablation Shapes in Refractive Surgery
13
作者 Guang-Ming Dai 《Journal of Applied Mathematics and Physics》 2017年第8期1521-1528,共8页
In refractive surgery, the cubic spline fit for the transition zone breaks down for myopia and myopic meridians in mixed astigmatism as in many cases the cubic spline function runs into negative values. In this paper,... In refractive surgery, the cubic spline fit for the transition zone breaks down for myopia and myopic meridians in mixed astigmatism as in many cases the cubic spline function runs into negative values. In this paper, the complementary error function is proposed instead of the cubic spline function as the transition zone function, due to the availability of analytical expression of its derivatives and the nonnegativity fact. It is shown that with the use of the complementary error function, transition zones for all refractive types work correctly. 展开更多
关键词 error function COMPLEMENTARY error function VISION CORRECTION Refractive Surgery Treatment Algorithm
在线阅读 下载PDF
Generalised Error Functions from the Kerr Metric
14
作者 唐文林 罗子人 刘润球 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第3期12-16,共5页
Motivated by the effort to understand the mathematical structure underlying the Teukolsky equations in a Kerr metric background, a homogeneous integral equation related to the prolate spheroidal function is studied. F... Motivated by the effort to understand the mathematical structure underlying the Teukolsky equations in a Kerr metric background, a homogeneous integral equation related to the prolate spheroidal function is studied. From the consideration of the Fredholm determinant of the integral equation, a family of generalized error function is defined, with which the Fredholm determinant of the sinc kernel is also evaluated. An analytic solution of a special ease of the fifth Painlev~ transcendent is then worked out explicitly. 展开更多
关键词 of IS exp in Generalised error functions from the Kerr Metric from
原文传递
Gap Functions and Error Bounds for Set-Valued Vector Quasi Variational Inequality Problems
15
作者 Rachana Gupta Aparna Mehra 《Applied Mathematics》 2017年第12期1903-1917,共15页
One of the classical approaches in the analysis of a variational inequality problem is to transform it into an equivalent optimization problem via the notion of gap function. The gap functions are useful tools in deri... One of the classical approaches in the analysis of a variational inequality problem is to transform it into an equivalent optimization problem via the notion of gap function. The gap functions are useful tools in deriving the error bounds which provide an estimated distance between a specific point and the exact solution of variational inequality problem. In this paper, we follow a similar approach for set-valued vector quasi variational inequality problems and define the gap functions based on scalarization scheme as well as the one with no scalar parameter. The error bounds results are obtained under fixed point symmetric and locally α-Holder assumptions on the set-valued map describing the domain of solution space of a set-valued vector quasi variational inequality problem. 展开更多
关键词 SET-VALUED VECTOR QUASI Variational Inequality Problem GAP function Regularized GAP function error Bounds Fixed Point Symmetric MAP α-Holder MAP
在线阅读 下载PDF
Some Properties on the Error-Sum Function of Alternating Sylvester Series 被引量:1
16
作者 Huiping Jing Luming Shen 《Advances in Pure Mathematics》 2012年第6期459-463,共5页
The error-sum function of alternating Sylvester series is introduced. Some elementary properties of this function are studied. Also, the hausdorff dimension of the graph of such function is determined.
关键词 ALTERNATING SYLVESTER SERIES error-Sum function HAUSDORFF Dimension
在线阅读 下载PDF
Partial Functional Linear Models with ARCH Errors
17
作者 Yafei Wang Tianfa Xie Zhongzhan Zhang 《Open Journal of Statistics》 2018年第2期345-361,共17页
In this paper, the estimation of the parameters in partial functional linear models with ARCH(p) errors is discussed. With employing the functional principle component, a hybrid estimating method is suggested. The asy... In this paper, the estimation of the parameters in partial functional linear models with ARCH(p) errors is discussed. With employing the functional principle component, a hybrid estimating method is suggested. The asymptotic normality of the proposed estimators for both the linear parameter in the mean model and the parameter in the ARCH error model is obtained, and the convergence rate of the slope function estimate is established. Besides, some simulations and a real data analysis are conducted for illustration, and it is shown that the proposed method performs well with a finite sample. 展开更多
关键词 ASYMPTOTIC NORMALITY ARCH(p) errorS functionAL Principal Components Convergence Rate Least ABSOLUTE Deviation
在线阅读 下载PDF
Evaluation of Generalized Error Function via Fast-Converging Power Series
18
作者 Serdar Beji 《Advances in Pure Mathematics》 2024年第6期495-514,共20页
A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power... A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power series expansion developed in resolving the so-called Grandi’s paradox. Comparisons with accurate tabulated values for well-known cases such as the error function are presented using the expansions truncated at various orders. 展开更多
关键词 Generalized error function Gamma function Grandi’s Paradox Fast-Converging Power Series
在线阅读 下载PDF
OPTIMAL ERROR BOUNDS FOR THE CUBIC SPLINE INTERPOLATION OF LOWER SMOOTH FUNCTIONS(1)
19
作者 Ye Maodong Zhejiang University,China 《Analysis in Theory and Applications》 1993年第4期46-54,共9页
In this paper,the kernel of the cubic spline interpolation is given.An optimal error bound for the cu- bic spline interpolation of lower smooth functions is obtained.
关键词 AS OPTIMAL error BOUNDS FOR THE CUBIC SPLINE INTERPOLATION OF LOWER SMOOTH functionS 十义 义人
在线阅读 下载PDF
Auxiliary error and probability density function based neuro-fuzzy model and its application in batch processes
20
作者 贾立 袁凯 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第12期2013-2019,共7页
This paper focuses on resolving the identification problem of a neuro-fuzzy model(NFM) applied in batch processes. A hybrid learning algorithm is introduced to identify the proposed NFM with the idea of auxiliary erro... This paper focuses on resolving the identification problem of a neuro-fuzzy model(NFM) applied in batch processes. A hybrid learning algorithm is introduced to identify the proposed NFM with the idea of auxiliary error model and the identification principle based on the probability density function(PDF). The main contribution is that the NFM parameter updating approach is transformed into the shape control for the PDF of modeling error. More specifically, a virtual adaptive control system is constructed with the aid of the auxiliary error model and then the PDF shape control idea is used to tune NFM parameters so that the PDF of modeling error is controlled to follow a targeted PDF, which is in Gaussian or uniform distribution. Examples are used to validate the applicability of the proposed method and comparisons are made with the minimum mean square error based approaches. 展开更多
关键词 Batch process Auxiliary error model Probability density function Neuro-fuzzy model
在线阅读 下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部