scholarly journals Investigation of the existence domain for Dyakonov surface waves in the Sage computer algebra system

2021 ◽  
Vol 29 (2) ◽  
pp. 114-125
Author(s):  
Oleg K. Kroytor
Keyword(s):  
Surface Waves ◽  
Computer Algebra ◽  
Electromagnetic Waves ◽  
Computer Algebra System ◽  
Computer Experiments ◽  
Dielectric Tensor ◽  
Algebraic Equations ◽  
Existence Of A Solution ◽  
Theoretical Substantiation ◽  
Existence Domain

Surface electromagnetic waves (Dyakonov waves) propagating along a plane interface between an isotropic substance with a constant dielectric constant and an anisotropic crystal, whose dielectric tensor has a symmetry axis directed along the interface, are considered. It is well known that the question of the existence of such surface waves is reduced to the question of the existence of a solution to a certain system of algebraic equations and inequalities. In the present work, this system is investigated in the Sage computer algebra system. The built-in technique of exceptional ideals in Sage made it possible to describe the solution of a system of algebraic equations parametrically using a single parameter, with all the original quantities expressed in terms of this parameter using radicals. The remaining inequalities were only partially investigated analytically. For a complete study of the solvability of the system of equations and inequalities, a symbolic-numerical algorithm is proposed and implemented in Sage, and the results of computer experiments are presented. Based on these results, conclusions were drawn that require further theoretical substantiation.

scholarly journals Diffraction of Electromagnetic Waves on a Waveguide Joint

2018 ◽  
Vol 173 ◽  
pp. 02014 ◽  
Author(s):  
Mikhail Malykh ◽  
Leonid Sevastianov ◽  
Anastasiya Tyutyunnik ◽  
Nikolai Nikolaev
Keyword(s):  
Hilbert Space ◽  
Electromagnetic Field ◽  
Differential Equations ◽  
Helmholtz Equation ◽  
Computer Algebra ◽  
Electromagnetic Waves ◽  
Computer Algebra System ◽  
Infinite System ◽  
Hamiltonian Form ◽  
Helmholtz Equations

In general, the investigation of the electromagnetic field in an inhomogeneous waveguide doesn’t reduce to the study of two independent boundary value problems for the Helmholtz equation. We show how to rewrite the Helmholtz equations in the “Hamiltonian form” to express the connection between these two problems explicitly. The problem of finding monochromatic waves in an arbitrary waveguide is reduced to an infinite system of ordinary differential equations in a properly constructed Hilbert space. The calculations are performed in the computer algebra system Sage.

COMPUTING THE HAUSDORFF DISTANCE BETWEEN CURVED OBJECTS

2008 ◽  
Vol 18 (04) ◽  
pp. 307-320 ◽  
Author(s):  
HELMUT ALT ◽  
LUDMILA SCHARF
Keyword(s):  
Voronoi Diagram ◽  
Computer Algebra ◽  
Hausdorff Distance ◽  
Computer Algebra System ◽  
Shape Recognition ◽  
The Other ◽  
Algebraic Equations ◽  
Algebraic Computing ◽  
Intersection Points ◽  
The One

The Hausdorff distance between two sets of curves is a measure for the similarity of these objects and therefore an interesting feature in shape recognition. If the curves are algebraic computing the Hausdorff distance involves computing the intersection points of the Voronoi edges of the one set with the curves in the other. Since computing the Voronoi diagram of curves is quite difficult we characterize those points algebraically and compute them using the computer algebra system SYNAPS. This paper describes in detail which points have to be considered, by what algebraic equations they are characterized, and how they actually are computed.

Generation of Correlated Logistic-Normal Random Variates for Medical Decision Trees

1998 ◽  
Vol 37 (03) ◽  
pp. 235-238 ◽  
Author(s):  
M. El-Taha ◽  
D. E. Clark
Keyword(s):  
Monte Carlo ◽  
Decision Trees ◽  
Computer Algebra ◽  
Taylor Series ◽  
Computer Algebra System ◽  
Random Variable ◽  
Monte Carlo Analysis ◽  
Normal Random Variable ◽  
Medical Decision ◽  
Theoretical Results

AbstractA Logistic-Normal random variable (Y) is obtained from a Normal random variable (X) by the relation Y = (ex)/(1 + ex). In Monte-Carlo analysis of decision trees, Logistic-Normal random variates may be used to model the branching probabilities. In some cases, the probabilities to be modeled may not be independent, and a method for generating correlated Logistic-Normal random variates would be useful. A technique for generating correlated Normal random variates has been previously described. Using Taylor Series approximations and the algebraic definitions of variance and covariance, we describe methods for estimating the means, variances, and covariances of Normal random variates which, after translation using the above formula, will result in Logistic-Normal random variates having approximately the desired means, variances, and covariances. Multiple simulations of the method using the Mathematica computer algebra system show satisfactory agreement with the theoretical results.

The Maple computer algebra system: A review

1995 ◽  
Vol 10 (3) ◽  
pp. 329-337 ◽  
Author(s):  
John Hutton ◽  
James Hutton
Keyword(s):  
Computer Algebra ◽  
Computer Algebra System ◽  
System A

scholarly journals OPTIMALISASI MOTIVASI DAN PRESTASI BELAJAR MENGGUNAKAN MOODLE BERBANTUAN COMPUTER ALGEBRA SYSTEM (CAS)

2020 ◽  
Vol 9 (1) ◽  
pp. 53
Author(s):  
Kamhar Ngado ◽  
Rosnawati Rosnawati ◽  
Heri Retnawati ◽  
Sri Andayani
Keyword(s):  
Computer Algebra ◽  
Computer Algebra System

scholarly journals Generation of equations for shell models of turbulence in the Maple system

2021 ◽  
Vol 254 ◽  
pp. 02006
Author(s):  
Liubov Feshchenko ◽  
Gleb Vodinchar
Keyword(s):  
Computer Algebra ◽  
Power Law ◽  
Computer Algebra System ◽  
Nonlinear Interactions ◽  
Systems Of Equations ◽  
Shell Models ◽  
Quadratic Invariants ◽  
Automated Compilation ◽  
Shell Models Of Turbulence

The paper describes a technology for the automated compilation of equations for shell models of turbulence in the computer algebra system Maple. A general form of equations for the coefficients of nonlinear interactions is given, which will ensure that the required combination of quadratic invariants and power-law solutions is fulfilled in the model. Described the codes for the Maple system allowing to generate and solve systems of equations for the coefficients. The proposed technology allows you to quickly and accurately generate classes of shell models with the desired properties.

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