Xinyi Guan¹, Shaoqiang Tang^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.29, No.1, pp. 1-1, 2024, DOI:10.32604/icces.2024.010869

Abstract Inheriting a convergence difficulty explained by the Kolmogorov N-width [1], the advection-diffusion equation is not effectively solved by the Proper Generalized Decomposition [2] (PGD) method. In this paper, we propose a new strategy: Proper Generalized Decomposition with Coordinate Transformation (CT-PGD). Converting the mixed hyperbolic-parabolic equation to a parabolic one, it resumes the efficiency of convergence for advection-dominant problems. Combining PGD with CT-PGD, we solve advection-diffusion equation by much fewer degrees of freedom, hence improve the efficiency. The advection-dominant regime and diffusion-dominant regime are quantitatively classified by a threshold, computed numerically. Moreover, we find that appropriate More >

Peng Geng^1,*, Annan Yang², Yan Liu³

Journal on Artificial Intelligence, Vol.6, pp. 43-52, 2024, DOI:10.32604/jai.2024.047642 - 28 March 2024

Abstract This article presents a real-time localization method for Unmanned Aerial Vehicles (UAVs) based on continuous image processing. The proposed method employs the Scale Invariant Feature Transform (SIFT) algorithm to identify key points in multi-scale space and generate descriptor vectors to match identical objects across multiple images. These corresponding points in the image provide pixel positions, which can be combined with transformation equations, allow for the calculation of the UAV’s actual ground position. Additionally, the physical coordinates of matching points in the image can be obtained, corresponding to the UAV’s physical coordinates. The method achieves real-time More >

Tongming Qu¹, Shaocheng Di², Y. T. Feng^1,3,*, Min Wang⁴, Tingting Zhao³, Mengqi Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.128, No.1, pp. 129-144, 2021, DOI:10.32604/cmes.2021.016172 - 28 June 2021

Abstract This study presents an AI-based constitutive modelling framework wherein the prediction model directly learns from triaxial testing data by combining discrete element modelling (DEM) and deep learning. A constitutive learning strategy is proposed based on the generally accepted frame-indifference assumption in constructing material constitutive models. The low-dimensional principal stress-strain sequence pairs, measured from discrete element modelling of triaxial testing, are used to train recurrent neural networks, and then the predicted principal stress sequence is augmented to other high-dimensional or general stress tensor via coordinate transformation. Through detailed hyperparameter investigations, it is found that long short-term More >

Gen Xu, Danhe Chen, Xiang Zhang, Wenhe Liao^*

CMES-Computer Modeling in Engineering & Sciences, Vol.125, No.2, pp. 865-878, 2020, DOI:10.32604/cmes.2020.012844 - 12 October 2020

Abstract For the on-orbit flight missions, the model of orbit prediction is critical for the tasks with high accuracy requirement and limited computing resources of spacecraft. The precession-nutation model, as the main part of extended orbit prediction, affects the efficiency and accuracy of on-board operation. In this paper, the previous research about the conversion between the Geocentric Celestial Reference System and International Terrestrial Reference System is briefly summarized, and a practical concise precession-nutation model is proposed for coordinate transformation computation based on Celestial Intermediate Pole (CIP). The idea that simplifying the CIP-based model with interpolation method… More >

Jialuan He^1,2, Zirui Xing², Rong Hu², Jing Qiu^3,*, Shen Su^3,*, Yuhan Chai³, Yue Wu⁴

CMC-Computers, Materials & Continua, Vol.60, No.2, pp. 527-544, 2019, DOI:10.32604/cmc.2019.05586

Abstract Wireless broadband communication is widely used in maneuver command communications systems in many fields, such as military operations, counter-terrorism and disaster relief. How to reasonably formulate the directional antenna coverage strategy according to the mobile terminal dynamic distribution and guide the directional antenna dynamic coverage becomes a practical research topic. In many applications, a temporary wireless boardband base station is required to support wireless signal communications between many terminals from nearby vehicles and staffs. It is therefore important to efficiently set directional antenna while ensuring large enough coverage over dynamically distributed terminals. The wireless broadband More >

J.D. Turner¹ , A. Alnaqeb¹, A. Bani Younes¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.3, pp. 257-268, 2016, DOI:10.3970/cmes.2016.111.257

Abstract A singularity-free perturbation solution is presented for inverting the Cartesian to Geodetic transformation. Conventional approaches for inverting the transformation use the natural ellipsoidal coordinates, this work explores the use of the satellite ground-track vector as the differential correction variable. The geodetic latitude is recovered by well-known elementary means. A high-accuracy highperformance 3D vector-valued continued fraction iteration is constructed. Rapid convergence is achieved because the starting guess for the ground-track vector provides a maximum error of 30 m for the satellite height above the Earth's surface, throughout the LEO-GEO range of applications. As a result, a More >

Sang-Ri Yi¹, Boyoung Kim², Jun Won Kang^2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.2, pp. 77-104, 2015, DOI:10.3970/cmes.2015.106.077

Abstract This study is concerned with the development of new mixed unsplitfield perfectly matched layers (PMLs) for the simulation of plane electromagnetic waves in heterogeneous unbounded domains. To formulate the unsplit-field PML, a complex coordinate transformation is introduced to Maxwell's equations in the frequency domain. The transformed equations are converted back to the time domain via the inverse Fourier transform, to arrive at governing equations for transient electromagnetic waves within the PML-truncated computational domain. A mixed finite element method is used to solve the PML-endowed Maxwell equations. The developed PML method is relatively simple and straightforward More >

M.L. Xie¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.14, No.3, pp. 85-90, 2010, DOI:10.3970/icces.2010.014.085

Abstract Various basis function based on Fourier-Chebyshev Petrov-Galerkin spectral method is described for computation of temporal linear stability in a circular jet. Basis functions presented here are exponentially mapped Chebyshev functions. There is a linear dependence between the components of the vector field according to the perturbation continuum equation. Therefore, there are only two degrees of freedom. According to the principle of permutation and combination, the basis function has three basic forms, i.e., the radial, azimuthal or axial component is free. The results show that three eigenvalues for various cases are consistent, but the basis function More >

Xie Ming-Liang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.14, No.2, pp. 57-62, 2010, DOI:10.3970/icces.2010.014.057

Abstract Various basis function based on Fourier-Chebyshev Petrov-Galerkin spectral method is described for computation of temporal linear stability in a circular jet. Basis functions presented here are exponentially mapped Chebyshev functions. There is a linear dependence between the components of the vector field according to the perturbation continuum equation. Therefore, there are only two degrees of freedom. According to the principle of permutation and combination, the basis function has three basic forms, i.e., the radial, azimuthal or axial component is free. The results show that three eigenvalues for various cases are consistent, but the basis function More >

Xie Ming-Liang^1,2, Zhou Huai-Chun¹, Chan Tat-Leung³

CMES-Computer Modeling in Engineering & Sciences, Vol.46, No.3, pp. 271-290, 2009, DOI:10.3970/cmes.2009.046.271

Abstract A Fourier-Chebyshev Petrov-Galerkin spectral method is described for computation of temporal linear stability in a circular jet. Basis functions presented here are exponentially mapped Chebyshev functions. They satisfy the pole condition exactly at the origin, and can be used to expand vector functions efficiently by using the solenoidal condition. The mathematical formulation is presented in detail focusing on the analyticity of solenoidal vector field used for the approximation of the flow. The scheme provides spectral accuracy in the present cases studied and the numerical results are in agreement with former works. More >