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  Subjects -> MATHEMATICS (Total: 867 journals)
    - APPLIED MATHEMATICS (69 journals)
    - GEOMETRY AND TOPOLOGY (19 journals)
    - MATHEMATICS (645 journals)
    - MATHEMATICS (GENERAL) (40 journals)
    - NUMERICAL ANALYSIS (19 journals)
    - PROBABILITIES AND MATH STATISTICS (75 journals)

MATHEMATICS (645 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 538 Journals sorted alphabetically
Abakós     Open Access   (Followers: 3)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 2)
Academic Voices : A Multidisciplinary Journal     Open Access   (Followers: 2)
Accounting Perspectives     Full-text available via subscription   (Followers: 6)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 16)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 4)
ACM Transactions on Mathematical Software (TOMS)     Hybrid Journal   (Followers: 6)
ACS Applied Materials & Interfaces     Full-text available via subscription   (Followers: 21)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1)
Acta Mathematica     Hybrid Journal   (Followers: 10)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 5)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 5)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15)
Advances in Decision Sciences     Open Access   (Followers: 4)
Advances in Difference Equations     Open Access   (Followers: 1)
Advances in Fixed Point Theory     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 1)
Advances in Materials Sciences     Open Access   (Followers: 16)
Advances in Mathematical Physics     Open Access   (Followers: 6)
Advances in Mathematics     Full-text available via subscription   (Followers: 10)
Advances in Numerical Analysis     Open Access   (Followers: 4)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Pure and Applied Mathematics     Hybrid Journal   (Followers: 5)
Advances in Pure Mathematics     Open Access   (Followers: 4)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2)
African Journal of Educational Studies in Mathematics and Sciences     Full-text available via subscription   (Followers: 5)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 4)
Afrika Matematika     Hybrid Journal   (Followers: 1)
Air, Soil & Water Research     Open Access   (Followers: 7)
AKSIOMA Journal of Mathematics Education     Open Access   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 2)
Algebra Colloquium     Hybrid Journal   (Followers: 4)
Algebra Universalis     Hybrid Journal   (Followers: 2)
Algorithmic Operations Research     Full-text available via subscription   (Followers: 5)
Algorithms     Open Access   (Followers: 9)
Algorithms Research     Open Access   (Followers: 1)
American Journal of Biostatistics     Open Access   (Followers: 9)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 3)
American Journal of Mathematical Analysis     Open Access  
American Journal of Mathematics     Full-text available via subscription   (Followers: 7)
American Journal of Operations Research     Open Access   (Followers: 5)
American Mathematical Monthly     Full-text available via subscription   (Followers: 6)
An International Journal of Optimization and Control: Theories & Applications     Open Access   (Followers: 7)
Analele Universitatii Ovidius Constanta - Seria Matematica     Open Access   (Followers: 1)
Analysis     Hybrid Journal   (Followers: 2)
Analysis and Applications     Hybrid Journal   (Followers: 1)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 4)
Analysis Mathematica     Full-text available via subscription  
Annales Mathematicae Silesianae     Open Access  
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annales UMCS, Mathematica     Open Access   (Followers: 1)
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica     Open Access  
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Discrete Mathematics     Full-text available via subscription   (Followers: 6)
Annals of Mathematics     Full-text available via subscription  
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of the Alexandru Ioan Cuza University - Mathematics     Open Access  
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1)
Annals of West University of Timisoara - Mathematics     Open Access  
Annuaire du Collège de France     Open Access   (Followers: 5)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applications of Mathematics     Hybrid Journal   (Followers: 1)
Applied Categorical Structures     Hybrid Journal   (Followers: 2)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Mathematics     Open Access   (Followers: 3)
Applied Mathematics     Open Access   (Followers: 4)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 4)
Applied Mathematics - A Journal of Chinese Universities     Hybrid Journal  
Applied Mathematics Letters     Full-text available via subscription   (Followers: 1)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1)
Applied Network Science     Open Access  
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arab Journal of Mathematical Sciences     Open Access   (Followers: 2)
Arabian Journal of Mathematics     Open Access   (Followers: 2)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 1)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
Arnold Mathematical Journal     Hybrid Journal   (Followers: 1)
Artificial Satellites : The Journal of Space Research Centre of Polish Academy of Sciences     Open Access   (Followers: 17)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asian Journal of Algebra     Open Access   (Followers: 1)
Asian Journal of Current Engineering & Maths     Open Access  
Asian-European Journal of Mathematics     Hybrid Journal   (Followers: 2)
Australian Mathematics Teacher, The     Full-text available via subscription   (Followers: 7)
Australian Primary Mathematics Classroom     Full-text available via subscription   (Followers: 2)
Australian Senior Mathematics Journal     Full-text available via subscription   (Followers: 1)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Axioms     Open Access  
Baltic International Yearbook of Cognition, Logic and Communication     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
BIBECHANA     Open Access  
BIT Numerical Mathematics     Hybrid Journal  
BoEM - Boletim online de Educação Matemática     Open Access  
Boletim Cearense de Educação e História da Matemática     Open Access  
Boletim de Educação Matemática     Open Access  
Boletín de la Sociedad Matemática Mexicana     Hybrid Journal  
Bollettino dell'Unione Matematica Italiana     Full-text available via subscription   (Followers: 1)
British Journal of Mathematical and Statistical Psychology     Full-text available via subscription   (Followers: 21)
Bruno Pini Mathematical Analysis Seminar     Open Access  
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 7)
Bulletin des Sciences Mathamatiques     Full-text available via subscription   (Followers: 4)
Bulletin of Dnipropetrovsk University. Series : Communications in Mathematical Modeling and Differential Equations Theory     Open Access   (Followers: 1)
Bulletin of Mathematical Sciences     Open Access   (Followers: 1)
Bulletin of the Brazilian Mathematical Society, New Series     Hybrid Journal  
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3)
Bulletin of the Malaysian Mathematical Sciences Society     Hybrid Journal  
Calculus of Variations and Partial Differential Equations     Hybrid Journal  
Canadian Journal of Science, Mathematics and Technology Education     Hybrid Journal   (Followers: 17)
Carpathian Mathematical Publications     Open Access   (Followers: 1)
Catalysis in Industry     Hybrid Journal   (Followers: 1)
CEAS Space Journal     Hybrid Journal  
CHANCE     Hybrid Journal   (Followers: 5)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
ChemSusChem     Hybrid Journal   (Followers: 7)
Chinese Annals of Mathematics, Series B     Hybrid Journal  
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Mathematics     Open Access  
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Cogent Mathematics     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Collectanea Mathematica     Hybrid Journal  
College Mathematics Journal     Full-text available via subscription   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Commentarii Mathematici Helvetici     Hybrid Journal   (Followers: 1)
Communications in Contemporary Mathematics     Hybrid Journal  
Communications in Mathematical Physics     Hybrid Journal   (Followers: 1)
Communications On Pure & Applied Mathematics     Hybrid Journal   (Followers: 3)
Complex Analysis and its Synergies     Open Access   (Followers: 2)
Complex Variables and Elliptic Equations: An International Journal     Hybrid Journal  
Complexus     Full-text available via subscription  
Composite Materials Series     Full-text available via subscription   (Followers: 9)
Comptes Rendus Mathematique     Full-text available via subscription   (Followers: 1)
Computational and Applied Mathematics     Hybrid Journal   (Followers: 2)
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 2)
Computational Complexity     Hybrid Journal   (Followers: 4)
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 4)
Computational Methods and Function Theory     Hybrid Journal  
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Concrete Operators     Open Access   (Followers: 4)
Confluentes Mathematici     Hybrid Journal  
COSMOS     Hybrid Journal  
Cryptography and Communications     Hybrid Journal   (Followers: 12)
Cuadernos de Investigación y Formación en Educación Matemática     Open Access  
Cubo. A Mathematical Journal     Open Access  
Czechoslovak Mathematical Journal     Hybrid Journal   (Followers: 1)
Demographic Research     Open Access   (Followers: 11)
Demonstratio Mathematica     Open Access  
Dependence Modeling     Open Access  
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 28)
Developments in Clay Science     Full-text available via subscription   (Followers: 1)
Developments in Mineral Processing     Full-text available via subscription   (Followers: 3)
Dhaka University Journal of Science     Open Access  
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 2)
Discrete Mathematics     Hybrid Journal   (Followers: 7)
Discrete Mathematics & Theoretical Computer Science     Open Access  
Discrete Mathematics, Algorithms and Applications     Hybrid Journal   (Followers: 2)
Discussiones Mathematicae Graph Theory     Open Access   (Followers: 1)
Doklady Mathematics     Hybrid Journal  
Duke Mathematical Journal     Full-text available via subscription   (Followers: 1)
Edited Series on Advances in Nonlinear Science and Complexity     Full-text available via subscription  
Electronic Journal of Graph Theory and Applications     Open Access   (Followers: 2)
Electronic Notes in Discrete Mathematics     Full-text available via subscription   (Followers: 2)
Elemente der Mathematik     Full-text available via subscription   (Followers: 3)
Energy for Sustainable Development     Hybrid Journal   (Followers: 9)
Enseñanza de las Ciencias : Revista de Investigación y Experiencias Didácticas     Open Access  
Ensino da Matemática em Debate     Open Access  
Entropy     Open Access   (Followers: 4)
ESAIM: Control Optimisation and Calculus of Variations     Full-text available via subscription   (Followers: 1)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 4)
European Journal of Mathematics     Hybrid Journal   (Followers: 1)
European Scientific Journal     Open Access   (Followers: 2)
Experimental Mathematics     Hybrid Journal   (Followers: 3)
Expositiones Mathematicae     Hybrid Journal   (Followers: 2)
Facta Universitatis, Series : Mathematics and Informatics     Open Access  
Fasciculi Mathematici     Open Access  
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 4)
Fixed Point Theory and Applications     Open Access   (Followers: 1)
Formalized Mathematics     Open Access   (Followers: 2)
Foundations and Trends® in Econometrics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 | Last

Journal Cover Computational Mathematics and Modeling
  [SJR: 0.191]   [H-I: 9]   [8 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1573-837X - ISSN (Online) 1046-283X
   Published by Springer-Verlag Homepage  [2329 journals]
  • Modeling the Relaxation of Oscillations in an Electrolyzer with a Free
           Boundary
    • Authors: F. A. Anikeev; S. V. Anpilov; F. S. Zaitsev; N. P. Savenkova; A. V. Kalmykov
      Pages: 185 - 194
      Abstract: Numerical methods for modeling the behavior of an industrial aluminum electrolyzer are investigated and developed. Solving a prototype problem that brings out the specific features of aluminum electrolysis, we compare two approaches to investigating the relaxation of oscillations in an electrolyzer with a free boundary between the phases. The first approach is the classical finite-difference method while the second approach uses smoothed particle hydrodynamics (SPH). The SPH method had not been applied previously to model aluminum electrolysis and it required development in this context. In particular, a new algorithm was proposed for one of the SPH subproblems that allowed for the dependence of acceleration on the velocity. The computational characteristics and the accuracy of the two methods are compared for the relaxation of free interface oscillations. The strengths and weaknesses of the two methods are discussed, as well as their potential for applications. It is shown that SPH is applicable to more realistic three-dimensional problems, such as real-time feedback control of aluminum electrolysis that can ensure online prevention of the onset of MHD instability.
      PubDate: 2017-04-01
      DOI: 10.1007/s10598-017-9356-3
      Issue No: Vol. 28, No. 2 (2017)
       
  • Generalization of the Optical Theorem to the Case of Excitation of a Local
           Obstacle by a Multipole
    • Authors: Yu. A. Eremin
      Abstract: The optical theorem is generalized to the case of excitation of a local body by a multipole. To compute the extinction cross-section, it is sufficient to find the derivatives of the scattered field at the single point where the multipole is located. The relationship obtained in this article makes it possible to test software modules developed for studying wave diffraction on transparent bodies.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9354-5
       
  • A Method for the Recovery of Suface Waves From Seismic Data
    • Authors: Yang Jianxun
      Abstract: A new method for seismic data processing is considered. Surface traveling waves are recovered from these data and wave-dependent coefficients are determined. The results of the proposed method are consistent with the results reported by other Chinese researchers [4, 5].
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9361-6
       
  • Analytical and Numerical Solutions of Oscillating Flow at a Trapezoidal
           Pressurewaveform
    • Authors: M. Abdulhameed; R. Roslan; D. Vieru; S. Shafie
      Abstract: This study aimed to develop a mathematical model of an unsteady Burgers’ fluid in a circular cylinder with a trapezoidal pressure waveform described by an infinite Fourier series. An analytical solution was obtained for the governing equation using the Bessel transform method together with similarity arguments. The validity of the solution was verified using a numerical inversion method based on Stehfest’s method. Limiting cases were considered to examine the fluid flow performance of different fluids. Our results show that the Newtonian and Oldroyd-B fluids performed similar velocity time variation for the trapezoidal waveform of oscillating motion, whereas the velocity time variation was different for Maxwell and Burger’s fluids. Moreover, it is evident that the material constant of a Burgers’ fluid is another important factor that affects flow performance in an oscillating flow.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9357-2
       
  • A New Approach to n th Order Fuzzy Differential Equations
    • Authors: S. Tapaswini; S. Chakraverty; T. Allahviranloo
      Abstract: This paper proposes a new method based on fuzzy center and radius for solving n th order fuzzy differential equations. First, the fuzzy differential equation is solved in term of fuzzy center and then this solution is used to find the radius of the fuzzy solution. Finally using the solution of fuzzy center and radius, one obtains the solution of the governing fuzzy differential equation. The proposed method is illustrated by considering three cases with numerical examples along with one application problem of vibration. Results obtained are also compared with solutions by existing methods and are found to be in good agreement.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9364-3
       
  • Numerical Method for the Inverse Boundary-Value Problem of the Heat
           Equation
    • Authors: V. I. Dmitriev; L. V. Stolyarov
      Abstract: The article considers the inverse boundary-value problem of heat conduction which involves determining the time distribution of temperature on the boundary given the spatial distribution of the temperature at the final time instant. The problem is reduced to an integral equation of the first kind with a symmetrical kernel. The integral equation is solved by a special iterative method. Test examples demonstrate convergence and stability of the proposed method.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9352-7
       
  • A Numerical Method for Low-Frequency Electromagnetic Fields in a
           Nonhomogeneous Medium in the Case of H-Polarization
    • Authors: I. S. Barashkov; V. I. Dmitriev
      Abstract: We consider finite-difference modeling of the electromagnetic field in a nonhomogeneous medium in the case of H-polarization. At the interior grid points, the finite-difference approximation binds five neighboring values of the grid functions, which correspond to the five diagonals of the linear algebraic system matrix. The matrix is banded. The linear algebraic system is solved by decomposing the matrix into a product of an upper-triangular matrix and a lower-triangular matrix. The algorithm is implemented for complex matrices using double-precision arithmetic. We show how to use the grid function values obtained by solving the linear algebraic system to find the magnetic field at the corner point of the conductivity discontinuity boundary. Calculation of the field at the corner point of the conductivity discontinuity boundary is an independent difficult problem of mathematical modeling of electromagnetic fields in nonhomogeneous media that deserves special attention. An equation is obtained for the field value at the corner point of the boundary. The numerical results obtained for the electromagnetic field in a complex nonhomogeneous medium confirm the validity of this equation.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9362-5
       
  • Temperature Dependence of the Elastic Modulus in Three-Dimensional
           Generalized Thermoelasticity with Dual-Phase-Lag Effects
    • Authors: N. Sarkar
      Abstract: A three-dimensional problem for a homogeneous isotropic thermoelastic half-space solids with temperature-dependent mechanical properties subject to a time-dependent heat sources on the boundary of the half-space which is traction free is considered in the context of the generalized thermoelasticity with dual-phase-lag effects. The normal mode analysis and eigenvalue approach techniques are used to solve the resulting non-dimensional coupled field equations. Numerical results for the temperature, thermal stresses and displacement distributions are represented graphically and discussed. A comparison is made with the result obtained in the absence of the temperature dependent elastic modulus. Various problems of generalized thermoelasticity and conventional coupled dynamical thermoelasticity are deduced as special cases of our problem.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9358-1
       
  • Localization of the Activity Source in the Inverse Problem of
           Magnetoencephalography
    • Authors: T. V. Zakharova; P. I. Karpov; V. M. Bugaevskii
      Abstract: The article discusses the development of noninvasive preoperative methods for the localization of eloquent areas in the human brain. The accuracy with which such areas are localized directly determines the outcome of surgery. An analytical formula is derived for the solution of the forward problem that computes the magnetic field on the surface of the head from the known location and orientation of a current dipole in the low-frequency approximation in the spherical model. The inverse problem is also solved, reconstructing the location and orientation of the source given the magnetic field on the surface of the head. Qualitative analysis of the ellipsoidal model is carried out.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9353-6
       
  • Efficient Local Image Descriptors
    • Authors: A. A. Lukianitsa
      Abstract: We consider descriptors in polar and log-polar coordinates that produce compact description of the image near interest points. These descriptors may be used to establish one-to-one correspondence between points in two images. Algorithms to compute these descriptors are described and the results of a numerical experiment comparing them with SIFT and SURF descriptors are reported. The numerical experiment suggests that the proposed descriptors are highly efficient for finding conjugate points in two images.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9360-7
       
  • Application of Mixed Quadrature Rule on Electromagnetic Field Problems
    • Authors: S. R. Jena; D. Nayak; M. M. Acharya
      Abstract: This paper is concerned with the problem of determining the approximate solution of real definite integrals by means of the mixed quadrature rule, which has been implemented with the quasi-type singular integral of electromagnetic field problems. The main advantage of the proposed numerical integration method over electromagnetic field problems is its efficiency, less functional evaluation and simple applicability. Five test numerical examples are provided to compare the accuracy with other researchers.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9363-4
       
  • Search for an Analytical Solution in the Three-Dimensional
           Gross–Pitaevskii Equation
    • Authors: V. S. Laponin; N. P. Savenkova
      Abstract: The Gross–Pitaevskii equation is at the core of the mathematical problem of the propagation of a Bose–Einstein condensate (BEC). In this article, we look for an analytical soliton solution in the three-dimensional Gross–Pitaevskii equation. We compare our analytical solution with the various numerical soliton solutions (dark solitons, light solitons, reflected solitons) reported by many researchers for the case of BEC interacting with an external potential (an obstacle, a magnetic trap, etc.). Our analytical solution can be applied to find both the main and the reflected soliton solution.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9359-0
       
  • Conservative Difference Scheme for Maxwell Equations Describing a
           Nonstationary Nonlinear Response of Matter in a Semi-Classical
           Approximation
    • Authors: D. Yu. Zagurskii; I. G. Zakharova; V. A. Trofimov
      Abstract: A conservative difference scheme is constructed for the system of equations that describe, in the semi-classical approximation, resonance and nonresonance interaction of an electromagnetic pulse with matter. The conservativity of the scheme is proved. A cascade mechanism for the excitation of high energy levels in the medium under the impact of a narrow-spectrum electromagnetic pulse is demonstrated. In the cascade mechanism, if the spectrum does not contain a pulse of sufficiently high frequencies to trigger direct transitions from the ground state to high excited states, the molecules of the medium may still reach the high states through a series of successive transitions between nearer lying energy levels. This may lead to the appearance in the transmitted pulse of higher frequencies than those observed in the incident pulse. For a medium whose length is comparable with the spatial extent of the pulse, distortion of the transmitted pulse spectrum is observed. The absolute phase of the small-period pulse substantially affects the transformation of the pulse spectrum during the transmission through the matter. If the matter contains several close energy levels, the corresponding transition rates will depend on the absolute phase of the field. We demonstrate and explain the generation of the third harmonic during the interaction of the electromagnetic pulse with the medium due to the nonstationary and nonlinear character of the response.
      PubDate: 2017-03-20
      DOI: 10.1007/s10598-017-9355-4
       
  • Equality of OLS and Aitken Estimators
    • Authors: A. G. Belov
      Abstract: We investigate the properties of multiple linear regression estimators obtained by the Ordinary Least Squares method (OLS) and the Generalized Least Squares method (GLS, Aitken estimator) assuming substantially different errors in input data. We illustrate the mechanism that leads to fallacious conclusions about the quality of OLS and Aitken estimators based on visual graphical analysis of experimental data. Numerical simulation and comparative analysis of the estimators is carried out for simple and parabolic regression models.
      PubDate: 2016-12-19
      DOI: 10.1007/s10598-016-9346-x
       
  • L ∞ -Error Analysis for Parabolic Quasi-Variational Inequalities Related
           to Impulse Control Problems
    • Authors: Mohamed El Amine Bencheikh Le Hocine; Mohamed Haiour
      Abstract: This paper deals with the numerical analysis of the problem of parabolic quasi-variational inequalities related to impulse control problems. An optimal L ∞ -convergence of a piecewise linear finite element method is established using the concept of subsolution.
      PubDate: 2016-12-17
      DOI: 10.1007/s10598-016-9349-7
       
  • A Coupled Method for Solving a Class of Time Fractional
           Convection-Diffusion Equations with Variable Coefficients
    • Authors: Ali Taghavi; Afshin Babaei; Alireza Mohammadpour
      Abstract: In this article, a coupled method based on the Laplace and differential transformations is applied to solve a class of time fractional convection-diffusion equations. The fractional derivatives are described in the Caputo sense. The method consists of implementing the Laplace transformation at first, then performing the differential transform method (DTM) on the resulting equations. Several examples are given to validate the proposed method.
      PubDate: 2016-12-17
      DOI: 10.1007/s10598-016-9350-1
       
  • Existence of Universal Functions for the Class of Linear k -Valued
           Functions with Moderate k
    • Authors: A. A. Voronenko; N. K. Voronova; V. P. Il’yutko
      Abstract: The article describes the construction of discrete functions which, by some of their values, specify (generate) arbitrary linear functions. The cases of prime and sufficiently large composite k have been considered previously. In the present study we finally solve the problem of existence of such functions for almost all k and n variables. The proof of the probabilistic upper bound and the general approach are due to A. A. Voronenko. The proof for small k has been developed by N. K. Voronova. The proof for k from 21 to 48 is the result of indispensable cooperation of V. P. Il’yutko and A. A. Voronenko.
      PubDate: 2016-12-17
      DOI: 10.1007/s10598-016-9347-9
       
  • Many Exact Solutions for a Higher-Order Nonlinear Schrödinger Equation
           with Non-Kerr Terms Describing the Propagation of Femtosecond Optical
           Pulses in Nonlinear Optical Fibers
    • Authors: Elsayed M. E. Zayed; Yasser A. Amer
      Abstract: In this article, we apply two powerful methods, namely the first integral method and a direct algebraic method for constructing many exact solutions for the higher-order nonlinear Schrödinger equation with non-Kerr terms that describes the propagation of femtosecond optical pulses in nonlinear optical fibers. Using a simple transformation, we reduce the given equation to a nonlinear ordinary differential equation (ODE). Various solutions of the resulting nonlinear ODE are obtained by using the above two methods. A comparison between our recent results and the well-known results is given.
      PubDate: 2016-12-17
      DOI: 10.1007/s10598-016-9351-0
       
  • A Control Problem with a Partially Known Initial Condition
    • Abstract: We consider a linear control problem with a partially known initial condition. Kalman’s observability theory of linear controlled system is applied to derive constructive sufficient conditions under which the control process to attain a terminal set M can be decomposed into the following stages: first collect information on system output, then apply this information to reconstruct the system’s initial state, and finally proceed with active control to attain the terminal set M.
      PubDate: 2016-12-16
      DOI: 10.1007/s10598-016-9341-2
       
  • Testing the First Order Accurate Godunov Method on Some Prototype and
           Applied Problems
    • Abstract: The Godunov method of first order accuracy continues to attract the attention of researchers both because of its simple implementation and its sufficiently high numerical accuracy subject to relatively modest resource requirements. However, it is necessary to constantly verify that the method indeed produces acceptable accuracy. We test the method on a number of one- and two-dimensional prototype problems and compare the results with analytical and numerical solutions obtained by higher accuracy schemes. The results for the method tested are quite acceptable. We also compare the solutions of applied problems on flows in supersonic, freely expanding jets and on supersonic flow past blunt bodies. The results for these problems are also positive.
      PubDate: 2016-12-16
      DOI: 10.1007/s10598-016-9342-1
       
 
 
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