The present paper proves that if（x） ∈ C[0,1], changes its sign exactly l times at 0 〈 y1〈 y2 … 〈 y1 〈 1 in （0, 1）, then there exists a pn（x） ∈ Пn（＋）, such that ｜f（x）- p（x）/pn（x）｜≤ Cωφ（f,n^...The present paper proves that if（x） ∈ C[0,1], changes its sign exactly l times at 0 〈 y1〈 y2 … 〈 y1 〈 1 in （0, 1）, then there exists a pn（x） ∈ Пn（＋）, such that ｜f（x）- p（x）/pn（x）｜≤ Cωφ（f,n^（-1/2））, where ρ（x） is defined by ρ（x）={^lПi=1（x-yi）,if f （x）≥0 for x ∈（y1,1）, {-^lПi=1（x-yi）,if f （x）〈0 for x ∈（y1,1）, which improves and generalizes the result of .展开更多
The magnetohydrodynamics （MHD） Falkner-Skan flow of the Maxwell fluid is studied. Suitable transform reduces the partial differential equation into a nonlinear three order boundary value problem over a semi-infinite...The magnetohydrodynamics （MHD） Falkner-Skan flow of the Maxwell fluid is studied. Suitable transform reduces the partial differential equation into a nonlinear three order boundary value problem over a semi-infinite interval. An efficient approach based on the rational Chebyshev collocation method is performed to find the solution to the proposed boundary value problem. The rational Chebyshev collocation method is equipped with the orthogonal rational Chebyshev function which solves the problem on the semi-infinite domain without truncating it to a finite domain. The obtained results are presented through the illustrative graphs and tables which demonstrate the affectivity, stability, and convergence of the rational Chebyshev collocation method. To check the accuracy of the obtained results, a numerical method is applied for solving the problem. The variations of various embedded parameters into the problem are examined.展开更多
<div style="text-align:justify;"> As a generalized sensor, the RPC model with its accuracy equally matches the physical sensor model. Moreover, the accurate positioning combining with the flexibility i...<div style="text-align:justify;"> As a generalized sensor, the RPC model with its accuracy equally matches the physical sensor model. Moreover, the accurate positioning combining with the flexibility in application leads the RPC model to be the priority in photogrammetry processing. Generally, the RPC model is calculated through a control grid. Different RPC parameters solving methods and the operation efficiency all serve as variables in the accuracy of the model. In this paper, the ridge estimation iterative method, spectrum correction iteration, and conjugate gradient method are employed to solve RPC parameters;the accuracy and efficiency of three solving methods are analyzed and compared. The results show that ridge estimation iterative method and spectrum correction iteration have obvious advantages in accuracy. The ridge estimation iterative method has fewer iteration times and time con-sumption, and spectrum correction iteration has more stable precision. </div>展开更多
基金Supported in part by National Natural Science Foundations of China under the grant number 10471130
文摘The present paper proves that if（x） ∈ C[0,1], changes its sign exactly l times at 0 〈 y1〈 y2 … 〈 y1 〈 1 in （0, 1）, then there exists a pn（x） ∈ Пn（＋）, such that ｜f（x）- p（x）/pn（x）｜≤ Cωφ（f,n^（-1/2））, where ρ（x） is defined by ρ（x）={^lПi=1（x-yi）,if f （x）≥0 for x ∈（y1,1）, {-^lПi=1（x-yi）,if f （x）〈0 for x ∈（y1,1）, which improves and generalizes the result of .
基金supported by the Imam Khomeini International University of Iran(No.751166-1392)the Deanship of Scientific Research(DSR)in King Abdulaziz University of Saudi Arabia
文摘The magnetohydrodynamics （MHD） Falkner-Skan flow of the Maxwell fluid is studied. Suitable transform reduces the partial differential equation into a nonlinear three order boundary value problem over a semi-infinite interval. An efficient approach based on the rational Chebyshev collocation method is performed to find the solution to the proposed boundary value problem. The rational Chebyshev collocation method is equipped with the orthogonal rational Chebyshev function which solves the problem on the semi-infinite domain without truncating it to a finite domain. The obtained results are presented through the illustrative graphs and tables which demonstrate the affectivity, stability, and convergence of the rational Chebyshev collocation method. To check the accuracy of the obtained results, a numerical method is applied for solving the problem. The variations of various embedded parameters into the problem are examined.
文摘<div style="text-align:justify;"> As a generalized sensor, the RPC model with its accuracy equally matches the physical sensor model. Moreover, the accurate positioning combining with the flexibility in application leads the RPC model to be the priority in photogrammetry processing. Generally, the RPC model is calculated through a control grid. Different RPC parameters solving methods and the operation efficiency all serve as variables in the accuracy of the model. In this paper, the ridge estimation iterative method, spectrum correction iteration, and conjugate gradient method are employed to solve RPC parameters;the accuracy and efficiency of three solving methods are analyzed and compared. The results show that ridge estimation iterative method and spectrum correction iteration have obvious advantages in accuracy. The ridge estimation iterative method has fewer iteration times and time con-sumption, and spectrum correction iteration has more stable precision. </div>
