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ORTHOGONAL POLYNOMIALS AND DETERMINANT FORMULAS OF FUNCTION-VALUED PADE-TYPE APPROXIMATION USING FOR SOLUTION OF INTEGRAL EQUATIONS 被引量:2
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作者 顾传青 潘宝珍 吴蓓蓓 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第6期853-860,共8页
To solve Fredholm integral equations of the second kind, a generalized linear functional is introduced and a new function-valued Padé-type approximation is defined. By means of the power series expansion of the s... To solve Fredholm integral equations of the second kind, a generalized linear functional is introduced and a new function-valued Padé-type approximation is defined. By means of the power series expansion of the solution, this method can construct an approximate solution to solve the given integral equation. On the basis of the orthogonal polynomials, two useful determinant expressions of the numerator polynomial and the denominator polynomial for Padé-type approximation are explicitly given. 展开更多
关键词 generalized linear functional function-valued Padé-type approximation Fredholm integral equation orthogonal polynomial determinant formula
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Rough Integrals Generated by Function Rough Sets 被引量:1
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作者 YU Xiu-qing XU Feng-sheng 《Chinese Quarterly Journal of Mathematics》 CSCD 2011年第2期296-299,共4页
The concepts of the lower approximation integral,the upper approximation integral and rough integrals are given on the basis of function rough sets.Based on these concepts,the relation of the lower approximation integ... The concepts of the lower approximation integral,the upper approximation integral and rough integrals are given on the basis of function rough sets.Based on these concepts,the relation of the lower approximation integrals,the relation of the upper approximation integrals,the relation of rough integrals,and the double median theorem of rough integrals are discussed.Rough integrals have finite contraction characteristic and finite extension characteristic. 展开更多
关键词 function rough sets the lower approximation integral the upper approximation integral rough integrals
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APPROXIMATION OF SINGULAR INTEGRALS BY INTERPOLATING SPLINES
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作者 王建忠 《Acta Mathematica Scientia》 SCIE CSCD 1991年第1期20-31,共12页
In this paper we are mainly concerned with the approximation of the following type of singular Integrals: where w(t)≥0 is a weight function, f(x) a real continuous function on [a, b], satisfying certain smooth condit... In this paper we are mainly concerned with the approximation of the following type of singular Integrals: where w(t)≥0 is a weight function, f(x) a real continuous function on [a, b], satisfying certain smooth conditions, and the integral is of Canchy principal value. 展开更多
关键词 In APPROXIMATION OF SINGULAR integralS BY INTERPOLATING SPLINES
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APPROXIMATION BY INTEGRAL TYPE MEYER-KONIG-ZELLER OPERATORS ON A SIMPLEX
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作者 Xiong Jingyi and Yang Ruyue(Ningxia University, China) 《Analysis in Theory and Applications》 1997年第1期43-50,共8页
Letbe a simplex in The integral type Meyer-Komg-Zeller operators are constructed on the simplex T, and the degree of approximation of these operators for L'-functions is obtained.
关键词 II APPROXIMATION BY integral TYPE MEYER-KONIG-ZELLER OPERATORS ON A SIMPLEX
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RESTRICTED NONLINEAR APPROXIMATION AND SINGULAR SOLUTIONS OF BOUNDARY INTEGRAL EQUATIONS
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作者 Reinhard Hochmuth (Freie Universitat Berlin, Germany) 《Approximation Theory and Its Applications》 2002年第1期1-25,共25页
This paper studies several problems , which are potentially relevant for the construction of adaptive numerical schemes. First, biorthogonal spline wavelets on [0,1] are chosen as a starting point for characterization... This paper studies several problems , which are potentially relevant for the construction of adaptive numerical schemes. First, biorthogonal spline wavelets on [0,1] are chosen as a starting point for characterizations of functions in Besom spaces B(?)(0,1) with 0<σ<∞ and (1+σ)-1<γ<∞. Such function spaces are known to be related to nonlinear approximation. Then so called restricted nonlinear approximation procedures with respect to Sobolev space norms are considered. Besides characterization results Jackson type estimates for various tree-type and tresholding algorithms are investigated. Finally known approximation results for geometry induced singularity functions of boundary integeral equations are combined with the characterization results for restricted nonlinear approximation to show Besov space regularity results. 展开更多
关键词 In RESTRICTED NONLINEAR APPROXIMATION AND SINGULAR SOLUTIONS OF BOUNDARY integral EQUATIONS
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APPROXIMATION OF SPHERICAL MEANS OF MULTIPLE FOURIER INTEGRALS AND FOURIER SERIES ON SET OF FULL MEASURE
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作者 Wang Shiming Zhejiang Institute of Technology, China Math. Section Dept. of Basic Courses Zhejiang Institute of Technology, Hangzhou, 310014, China 《Analysis in Theory and Applications》 1994年第2期17-23,共7页
In this paper we consider the approximation for functions in some subspaces of L^2 by spherical means of their Fourier integrals and Fourier series on set of full measure. Two main theorems are obtained.
关键词 SET Th Pro APPROXIMATION OF SPHERICAL MEANS OF MULTIPLE FOURIER integralS AND FOURIER SERIES ON SET OF FULL MEASURE WANG
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Asymptotic Analysis Methods for Structural Reliability 被引量:3
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作者 Zhao Guofan , Li Yungui Wang Hengdong Professor, Dept. of Civil Engineering, Dalian University of Technology, Dalian 116024 Ph. Doctor, China Academy of Building Research, Beijing 100013 Ph. Doctor, Dept. of Civil Engineering, Dalian University of Technology, Dalian 116024 《China Ocean Engineering》 SCIE EI 1995年第3期303-310,共8页
Applying Laplace asymptotic approximation of integral, asymptotic analysis methods of structural reliability are proposed in generalized and orthogonal random space. Analytic results show that the proposed methods are... Applying Laplace asymptotic approximation of integral, asymptotic analysis methods of structural reliability are proposed in generalized and orthogonal random space. Analytic results show that the proposed methods are simple in calculation and accurate enough for problems of continuous random variables. 展开更多
关键词 STRUCTURE RELIABILITY random variable asymptotic approximation of integral
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LOCAL SALINE APPROXIMATION METHODS FOR SINGULAR PRODUCT INTEGRATION 被引量:1
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作者 C. Dagnino V. Demichelis E. Santi 《Analysis in Theory and Applications》 1996年第3期37-51,共15页
The purpose of this paper is to propose and study local spline approximation methods for singular product integration,for which;i)the precision degree is the highest possible using splint approximation; ii) the nodes ... The purpose of this paper is to propose and study local spline approximation methods for singular product integration,for which;i)the precision degree is the highest possible using splint approximation; ii) the nodes fan be assumed equal to arbitrary points,where the integrand function f is known; iii) the number of the requested evaluations of f at the nodes is low,iv) a satisfactory convergence theory can be proved. 展开更多
关键词 LOCAL SALINE APPROXIMATION METHODS FOR SINGULAR PRODUCT INTEGRATION
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Unsteady Rotative Flow of Non-Newtonian Fluid in an Annular Pipe
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作者 黄军旗 刘慈群 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1995年第4期345-350,共6页
This paper .Studies power law no-Newtonian fluid rotative flow. in an annularpipe. The governing equation is nonlinear one, we linearized the governing equationby assuming that partial factor is at state. With Lapla... This paper .Studies power law no-Newtonian fluid rotative flow. in an annularpipe. The governing equation is nonlinear one, we linearized the governing equationby assuming that partial factor is at state. With Laplace transform we obtain ananalytical solution of the problem In the paper several groups of curves are given.these curves reflect the temporal change law and. spatial distribution of fluid velocity.In addition.we study the effection of power law index on the flow field the resultindicates that when the power law index n < l. the flow velocity is highly sensitive tothe index. and this fact is importanl in related engineering decisions. 展开更多
关键词 non-Newtonian power law fluid. annular pipe rotative flow.integral transform . approximate solution
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Identifying Malaria Hotspots Regions in Ghana Using Bayesian Spatial and Spatiotemporal Models
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作者 Abdul-Karim Iddrisu Dominic Otoo +4 位作者 Gordon Hinneh Yakubu Dekongmene Kanyiri Kanimam Yaaba Samuel Cecilia Kubio Francis Balungnaa Dhari Veriegh 《Infectious Diseases & Immunity》 CSCD 2024年第2期69-78,共10页
Background:Malaria remains a significant public health concern in Ghana,with varying risk levels across different geographical areas.Malaria affects millions of people each year and imposes a substantial burden on the... Background:Malaria remains a significant public health concern in Ghana,with varying risk levels across different geographical areas.Malaria affects millions of people each year and imposes a substantial burden on the health care system and population.Accurate risk estimation and mapping are crucial for effectively allocating resources and implementing targeted interventions to identify regions with disease hotspots.This study aimed to identify regions exhibiting elevated malaria risk so that public health interventions can be implemented,and to identify malaria risk predictors that can be controlled as part of public health interventions for malaria control.Methods:The data on laboratory-confirmed malaria cases from 2015 to 2021 were obtained from the Ghana Health Service and Ghana Statistical Service.We studied the spatial and spatiotemporal patterns of the relative risk of malaria using Bayesian spatial and spatiotemporal models.The malaria risk for each region was mapped to visually identify regions with malaria hotspots.Clustering and heterogeneity of disease risks were established using correlated and uncorrelated structures via the conditional autoregressive and Gaussian models,respectively.Parameter estimates from the marginal posterior distribution were estimated within the Integrated Nested Laplace Approximation using the R software.Results:The spatial model indicated an increased risk of malaria in the North East,Bono East,Ahafo,Central,Upper West,Brong Ahafo,Ashanti,and Eastern regions.The spatiotemporal model results highlighted an elevated malaria risk in the North East,Upper West,Upper East,Savannah,Bono East,Central,Bono,and Ahafo regions.Both spatial and spatiotemporal models identified the North East,Upper West,Bono East,Central,and Ahafo Regions as hotspots for malaria risk.Substantial variations in risk were evident across regions(H=104.9,P<0.001).Although climatic and economic factors influenced malaria infection,statistical significance was not established.Conclusions:Malaria risk was clustered and varied among regions in Ghana.There are many regions in Ghana that are hotspots for malaria risk,and climate and economic factors have no significant influence on malaria risk.This study could provide information on malaria transmission patterns in Ghana,and contribute to enhance the effectiveness of malaria control strategies. 展开更多
关键词 MALARIA Disease hotspot Bayesian modeling Conditional auto-regressive Integrated Nested Laplace Approximation Spatial and spatiotemporal models
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A New Method for Analyzing VOCs Emission from Dry Materials 被引量:4
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作者 ZHANG Tao JIA Li 《Journal of Thermal Science》 SCIE EI CAS CSCD 2008年第3期228-232,共5页
An approximate integral method for volatile compounds emission from plate is presented in this paper. The gas-phase mass transfer resistance was neglected for simplifying computation. Compared to Laplace Transformatio... An approximate integral method for volatile compounds emission from plate is presented in this paper. The gas-phase mass transfer resistance was neglected for simplifying computation. Compared to Laplace Transformation Method, the method suggested is simple, and emission flux, chamber concentration of volatile compounds and concentration distribution of volatile compounds in the material can be determined conveniently. Results of the present method show good agreement with experimental data. The influence of CO, D, K and N on concentration of total volatile organic compounds (TVOC) in the air is also calculated. 展开更多
关键词 approximate integral method emission flux concentration distribution
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Freezing of Water in a Slab with Boundary Conditions of the Third Kind
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作者 Bu-Xuan Wang Ji Ma(Thermal Eng. Dept., Tsinghua Univ., Beijing 100084, China) 《Journal of Thermal Science》 SCIE EI CAS CSCD 1994年第1期15-22,共8页
Predictions for freezing heat transfer in a slab with convective boundary conditions at the cold surfaceare obtained from heat balance integral approximations, which consider conduction as the only modeof heat transfe... Predictions for freezing heat transfer in a slab with convective boundary conditions at the cold surfaceare obtained from heat balance integral approximations, which consider conduction as the only modeof heat transfer in both the solid and liquid and consider durations of precooling and freezing in theheat transfer process. The thermal penetration dimensionless parameter or is presented to distinguishtwO cases of freezing, and analytical results for α≥ 1 are given in this paper. An experimental investigation on freezing of water is reported for comparison with the one-dimensional conduction model toshow that experimental modeling for freezing heat transfer with convective boundary conditions usingPeltter devices is feasible. The comparison also demonstrated that the freezing rate in this case wasdecreased by natural convection in the liquid just as freezing with boundary conditions of the first kindand phase change approximately proceeds linearly with time rather than with square root of time atthe initiation of freezing. 展开更多
关键词 freezing heat transfer connective boundary condition experimental modeling heat balance integral approximation
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