20 research outputs found

    A family of high-order multistep methods with vanished phase-lag and its derivatives for the numerical solution of the Schrödinger equation

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    AbstractMany simulation algorithms (chemical reaction systems, differential systems arising from the modelling of transient behaviour in the process industries etc.) contain the numerical solution of systems of differential equations. For the efficient solution of the above mentioned problems, linear multistep methods or Runge–Kutta single-step methods are used. For the simulation of chemical procedures the radial Schrödinger equation is used frequently. In the present paper we will study a class of linear multistep methods. More specifically, the purpose of this paper is to develop an efficient algorithm for the approximate solution of the radial Schrödinger equation and related problems. This algorithm belongs in the category of the multistep methods. In order to produce an efficient multistep method the phase-lag property and its derivatives are used. Hence the main result of this paper is the development of an efficient multistep method for the numerical solution of systems of ordinary differential equations with oscillating or periodical solutions. The reason of their efficiency, as the analysis proved, is that the phase-lag and its derivatives are eliminated. Another reason of the efficiency of the new obtained methods is that they have high algebraic orde

    エネルギー関数を持つ発展方程式に対する幾何学的数値計算法

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    学位の種別: 課程博士審査委員会委員 : (主査)東京大学教授 松尾 宇泰, 東京大学教授 中島 研吾, 東京大学准教授 鈴木 秀幸, 東京大学准教授 長尾 大道, 東京大学准教授 齋藤 宣一University of Tokyo(東京大学

    Mathematical Modeling with Differential Equations in Physics, Chemistry, Biology, and Economics

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    This volume was conceived as a Special Issue of the MDPI journal Mathematics to illustrate and show relevant applications of differential equations in different fields, coherently with the latest trends in applied mathematics research. All the articles that were submitted for publication are valuable, interesting, and original. The readers will certainly appreciate the heterogeneity of the 10 papers included in this book and will discover how helpful all the kinds of differential equations are in a wide range of disciplines. We are confident that this book will be inspirational for young scholars as well

    Some procedures for the construction of high-order exponentially fitted Runge–Kutta–Nyström methods of explicit type

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    This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2018) Abstract The construction of high-order exponentially fitted Runge–Kutta–Nyström (EFRKN) methods of explicit type for the numerical solution of oscillatory differential systems is analyzed. Based on two basic symmetric and symplectic EFRKN methods of reference we present two procedures for constructing high-order explicit methods. The first procedure is based on composition methods and it allows the construction of high-order explicit EFRKN methods which are symmetric and symplectic. The second proced... Title of program: SVI-IIEXPOreferee.for and SVI-IIvarreferee.for Catalogue Id: AEOO_v1_0 Nature of problem Some models in astronomy and astrophysics, quantum mechanics and nuclear physics lead to second-order oscillatory differential systems. The solution of these oscillatory models requires accurate and efficient numerical methods. The codes SVI-IIEXPOreferee.for and SVI-IIvarreferee.for were developed for this purpose. Versions of this program held in the CPC repository in Mendeley Data AEOO_v1_0; SVI-IIEXPOreferee.for and SVI-IIvarreferee.for; 10.1016/j.cpc.2012.12.01

    Mathematical modelling of cancer invasion and metastatic spread

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    Metastatic spread—the dissemination of cancer cells from a primary tumour with subsequent re-colonisation at secondary sites in the body—causes around 90% of cancer-related deaths. Mathematical modelling may provide a complementary approach to help understand the complex mechanisms underlying metastasis. In particular, the spatiotemporal evolution of individual cancer cells during the so-called invasion-metastasis cascade—i.e. during cancer cell invasion, intravasation, vascular travel, extravasation and metastatic growth—is an aspect not yet explored through existing mathematical models. In this thesis, such a spatially explicit hybrid multi-organ metastasis modelling framework is developed. It describes the invasive growth dynamics of individual cancer cells both at a primary site and at potential secondary metastatic sites in the body, as well as their transport from the primary to the secondary sites. Throughout, the interactions between the cancer cells, matrix-degrading enzymes (MDEs) and the extracellular matrix (ECM) are accounted for. Furthermore, the individual-based framework models phenotypic variation by distinguishing between cancer cells of an epithelial-like, a mesenchymal-like and a mixed phenotype. It also describes permanent and transient mutations between these cell phenotypes in the form of epithelial-mesenchymal transition (EMT) and its reverse process mesenchymal-epithelial transition (MET). Both of these mechanisms are implemented at the biologically appropriate locations of the invasion-metastasis cascade. Finally, cancer cell dormancy and death at the metastatic sites are considered to model the frequently observed maladaptation of metastasised cancer cells to their new microenvironments. To investigate the EMT-process further, an additional three-dimensional discrete-continuum model of EMT- and MET-dependent cancer cell invasion is developed. It consists of a hybrid system of partial and stochastic differential equations that describe the evolution of epithelial-like and mesenchymal-like cancer cells, again under the consideration of MDE concentrations and the ECM density. Using inverse parameter estimation and sensitivity analysis, this model is calibrated to an in vitro organotypic assay experiment that examines the invasion of HSC-3 cancer cells

    MS FT-2-2 7 Orthogonal polynomials and quadrature: Theory, computation, and applications

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    Quadrature rules find many applications in science and engineering. Their analysis is a classical area of applied mathematics and continues to attract considerable attention. This seminar brings together speakers with expertise in a large variety of quadrature rules. It is the aim of the seminar to provide an overview of recent developments in the analysis of quadrature rules. The computation of error estimates and novel applications also are described

    Generalized averaged Gaussian quadrature and applications

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    A simple numerical method for constructing the optimal generalized averaged Gaussian quadrature formulas will be presented. These formulas exist in many cases in which real positive GaussKronrod formulas do not exist, and can be used as an adequate alternative in order to estimate the error of a Gaussian rule. We also investigate the conditions under which the optimal averaged Gaussian quadrature formulas and their truncated variants are internal
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