Thematische Bibliographien / One-Way equations

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Auswahl der wissenschaftlichen Literatur zum Thema „One-Way equations“

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Veröffentlicht am 1. Februar 2025

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Zeitschriftenartikel zum Thema "One-Way equations"

Bschorr, Oskar, und Hans-Joachim Raida. „Factorized One-Way Wave Equations“. Acoustics 3, Nr. 4 (09.12.2021): 717–22. http://dx.doi.org/10.3390/acoustics3040045.

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The method used to factorize the longitudinal wave equation has been known for many decades. Using this knowledge, the classical 2nd-order partial differential Equation (PDE) established by Cauchy has been split into two 1st-order PDEs, in alignment with D’Alemberts’s theory, to create forward- and backward-traveling wave results. Therefore, the Cauchy equation has to be regarded as a two-way wave equation, whose inherent directional ambiguity leads to irregular phantom effects in the numerical finite element (FE) and finite difference (FD) calculations. For seismic applications, a huge number of methods have been developed to reduce these disturbances, but none of these attempts have prevailed to date. However, a priori factorization of the longitudinal wave equation for inhomogeneous media eliminates the above-mentioned ambiguity, and the resulting one-way equations provide the definition of the wave propagation direction by the geometric position of the transmitter and receiver.

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Halpern, Laurence, und Lloyd N. Trefethen. „Wide‐angle one‐way wave equations“. Journal of the Acoustical Society of America 84, Nr. 4 (Oktober 1988): 1397–404. http://dx.doi.org/10.1121/1.396586.

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Lee, Myung W., und Sang Y. Suh. „Optimization of one‐way wave equations“. GEOPHYSICS 50, Nr. 10 (Oktober 1985): 1634–37. http://dx.doi.org/10.1190/1.1441853.

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The theory of wave extrapolation is based on the square‐root equation or one‐way equation. The full wave equation represents waves which propagate in both directions. On the contrary, the square‐root equation represents waves propagating in one direction only.

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Towne, Aaron, und Tim Colonius. „One-way spatial integration of hyperbolic equations“. Journal of Computational Physics 300 (November 2015): 844–61. http://dx.doi.org/10.1016/j.jcp.2015.08.015.

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Bschorr, Oskar, und Hans-Joachim Raida. „One-Way Wave Equation Derived from Impedance Theorem“. Acoustics 2, Nr. 1 (10.03.2020): 164–71. http://dx.doi.org/10.3390/acoustics2010012.

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The wave equations for longitudinal and transverse waves being used in seismic calculations are based on the classical force/moment balance. Mathematically, these equations are 2nd order partial differential equations (PDE) and contain two solutions with a forward and a backward propagating wave, therefore also called “Two-way wave equation”. In order to solve this inherent ambiguity many auxiliary equations were developed being summarized under “One-way wave equation”. In this article the impedance theorem is interpreted as a wave equation with a unique solution. This 1st order PDE is mathematically more convenient than the 2nd order PDE. Furthermore the 1st order wave equation being valid for three-dimensional wave propagation in an inhomogeneous continuum is derived.

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Sheinman, Izhak, und Yeoshua Frostig. „Constitutive Equations of Composite Laminated One-Way Panels“. AIAA Journal 38, Nr. 4 (April 2000): 735–37. http://dx.doi.org/10.2514/2.1025.

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Sheinman, Izhak, und Yeoshua Frostig. „Constitutive equations of composite laminated one-way panels“. AIAA Journal 38 (Januar 2000): 735–37. http://dx.doi.org/10.2514/3.14474.

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You, Jiachun, Ru-Shan Wu und Xuewei Liu. „One-way true-amplitude migration using matrix decomposition“. GEOPHYSICS 83, Nr. 5 (01.09.2018): S387—S398. http://dx.doi.org/10.1190/geo2017-0625.1.

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To meet the requirement of true-amplitude migration and address the shortcomings of the classic one-way wave equations on the dynamic imaging, one-way true-amplitude wave equations were developed. Migration methods, based on the Taylor or other series approximation theory, are introduced to solve the one-way true-amplitude wave equations. This leads to the main weakness of one-way true-amplitude migration for imaging the complex or strong velocity — contrast media — the limited imaging angles. To deal with this issue, we apply a matrix decomposition method to accurately calculate the square-root operator and impose the boundary conditions of the one-way true-amplitude wave equations. Our migration method and the conventional one-way true-amplitude Fourier finite-difference (FFD) migration method are used by us to test and compare the imaging performance. The impulse responses in a strong velocity-contrast model prove that our migration method works for larger imaging angles than the one-way true-amplitude FFD method. The amplitude calculations in a strong-lateral velocity variation media with one reflector and in the Marmousi model demonstrate that our migration method provides better amplitude-preserving performance and offers higher structural imaging quality than the one-way true-amplitude FFD method. We also use field data to indicate the imaging enhancement and the feasibility of our method compared with the one-way true-amplitude FFD method. Our one-way true-amplitude migration method using matrix decomposition fully exploits the features of one-way true-amplitude wave equations with less approximation, and it is capable of producing more accurate amplitude estimations and potentially wider imaging angles.

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Bérczes, Attila, J. Ködmön und Attila Pethő. „A one-way function based on norm form equations“. Periodica Mathematica Hungarica 49, Nr. 1 (2004): 1–13. http://dx.doi.org/10.1023/b:mahu.0000040535.45427.38.

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Chen, Jing-bo, und Shu-yuan Du. „Multisymplectic Structures and Discretizations for One-way Wave Equations“. Letters in Mathematical Physics 79, Nr. 2 (15.11.2006): 213–20. http://dx.doi.org/10.1007/s11005-006-0119-x.

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Dissertationen zum Thema "One-Way equations"

Garay, Jose. „Asynchronous Optimized Schwarz Methods for Partial Differential Equations in Rectangular Domains“. Diss., Temple University Libraries, 2018. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/510451.

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Mathematics
Ph.D.
Asynchronous iterative algorithms are parallel iterative algorithms in which communications and iterations are not synchronized among processors. Thus, as soon as a processing unit finishes its own calculations, it starts the next cycle with the latest data received during a previous cycle, without waiting for any other processing unit to complete its own calculation. These algorithms increase the number of updates in some processors (as compared to the synchronous case) but suppress most idle times. This usually results in a reduction of the (execution) time to achieve convergence. Optimized Schwarz methods (OSM) are domain decomposition methods in which the transmission conditions between subdomains contain operators of the form \linebreak $\partial/\partial \nu +\Lambda$, where $\partial/\partial \nu$ is the outward normal derivative and $\Lambda$ is an optimized local approximation of the global Steklov-Poincar\'e operator. There is more than one family of transmission conditions that can be used for a given partial differential equation (e.g., the $OO0$ and $OO2$ families), each of these families containing a particular approximation of the Steklov-Poincar\'e operator. These transmission conditions have some parameters that are tuned to obtain a fast convergence rate. Optimized Schwarz methods are fast in terms of iteration count and can be implemented asynchronously. In this thesis we analyze the convergence behavior of the synchronous and asynchronous implementation of OSM applied to solve partial differential equations with a shifted Laplacian operator in bounded rectangular domains. We analyze two cases. In the first case we have a shift that can be either positive, negative or zero, a one-way domain decomposition and transmission conditions of the $OO2$ family. In the second case we have Poisson's equation, a domain decomposition with cross-points and $OO0$ transmission conditions. In both cases we reformulate the equations defining the problem into a fixed point iteration that is suitable for our analysis, then derive convergence proofs and analyze how the convergence rate varies with the number of subdomains, the amount of overlap, and the values of the parameters introduced in the transmission conditions. Additionally, we find the optimal values of the parameters and present some numerical experiments for the second case illustrating our theoretical results. To our knowledge this is the first time that a convergence analysis of optimized Schwarz is presented for bounded subdomains with multiple subdomains and arbitrary overlap. The analysis presented in this thesis also applies to problems with more general domains which can be decomposed as a union of rectangles.
Temple University--Theses

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Ruello, Maëlys. „Méthodes de propagation de type One-Way pour les équations de Navier-Stokes : vers le calcul des perturbations optimales“. Electronic Thesis or Diss., Toulouse, ISAE, 2024. http://www.theses.fr/2024ESAE0061.

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Les approches One-Way sont des méthodes de simulation numérique des phénomènes de propagation d’ondes dans une direction privilégiée, qui permettent de palier le défaut (suivi d’un seul mode) des méthodes modales tout en garantissant un coût de calcul faible par rapport à une simulation directe. Bien que ces méthodes soient utilisées depuis plus de cinquante ans dans divers domaines comme l’électromagnétisme et la géophysique, leur application en mécanique des fluides est plus récente avec les travaux pionniers de T. Colonius et A. Towne en 2015.Cette thèse possédait un double objectif. Dans un premier temps, il s’agissait de développer des méthodes de simulation de type One-Way dans le cadre des équations de Navier-Stokes en réalisant une extension de la méthodologie proposée dans les travaux de thèse de C. Rudel pour les équations d'Euler. Dans un second temps, elles ont été exploitées pour concevoir un outil numérique dans le but de calculer la perturbation optimale d’un écoulement. L’ensemble de ces développements a été éprouvé sur différentes problématiques représentatives et en considérant des situations de complexité croissante. En particulier, le cas d’un conduit partiellement revêtu d’un liner acoustique en présence d’une instabilité de surface a été traité à l’aide d’une approche de type méthode de décomposition de domaine basée sur les solveurs One-Way et comparé à la fois à des données expérimentales et des résultats issus d’autres solveurs numériques. De plus, la capacité des approches One-Way à propager des instabilités de couches limites et leur éventuel couplage a été observée. Enfin, un algorithme de calcul de perturbations optimales, basé sur une méthode adjointe, a été utilisé pour déterminer entre autres le forçage optimal et la réponse associée d'un écoulement de couche limite bidimensionnelle à Mach 4.5
One-Way approaches are numerical simulation methods for wave propagation phenomena in a preferred direction, which overcome the limitation (single-mode tracking) of modal methods while ensuring a low computational cost compared to a direct simulation. Although these methods have been used for over fifty years in various fields such as electromagnetism and geophysics, their application in fluid mechanics is more recent, with pioneering work by T. Colonius and A. Towne in 2015.This thesis had a dual objective. Firstly, it aimed to develop One-Way type simulation methods for the Navier-Stokes equations, by extending the methodology proposed in C. Rudel's thesis work for the Euler equations. Subsequently, these methods were used to develop a numerical tool for calculating optimal flow disturbance. All these developments have been tested on a number of representative problems, considering situations of increasing complexity. In particular, the case of a partially lined duct, in the presence of a surface instability, was treated using a domain decomposition method based on One-Way solvers, and compared with both experimental data and results from other numerical solvers. Additionally, the ability of One-Way approaches to propagate boundary layer instabilities and their possible coupling was observed. Finally, an algorithm for computing optimal perturbations, based on an adjoint method, was used to determine, among other things, the optimal forcing and associated response of a two-dimensional boundary layer flow at Mach 4.5

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Michalkovič, Aleksejus. „Netiesinės algebrinės lygčių sistemos sprendinių skaičiaus analizė“. Master's thesis, Lithuanian Academic Libraries Network (LABT), 2010. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2010~D_20100813_142631-54742.

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Vienas iš svarbiausių šiuolaikinės kriptografijos uždavinių yra saugių vienkrypčių funkcijų paieška. Dabartiniai mokslininkai skiria šiam klausimui ypatingą demėsį. Šiame darbe yra nagrinėjama viena iš naujausių vienkrypčių funkcijų – matricinio laipsnio funkcija. Ši funkcija yra panaudota netiesinės algebrinės lygčių sistemos sudarymui. Pagrindinis demėsys darbe yra skirtas šios lygčių sistemos analizei bei jos praktiniam taikymui. Nustatysime ar matricinio laipsnio funkcija gali būti panaudota kriptografijoje. Taip pat nustatysime lygčių sistemos sprendinių skaičiaus priklausomybę nuo jos parametrų: matricų eilės m bei grupės Z_p parametro p.
Since the introduction of Diffie-Hellman key agreement protocol in 1976 computer technology has made a giant step forward. Nowadays there is not much time left before quantum computers will be in every home. However it was theoretically proven that discrete logarithm problem which is the basis for Diffie-Hellman protocol could be solved in polynomial time using such computers. Such possibility would make D-H protocol insecure. Thus cryptologists are searching for different ways to improve the security of the protocol by using hard problems. One of the ways to do so is to introduce secure one-way functions (OWF). In this paper a new kind of OWF called the matrix power function will be analyzed. Professor Eligijus Sakalauskas introduced this function in 2007 and later used this function to construct a Diffie-Hellman type key agreement protocol using square matrices. This protocol is not only based on matrix power function but also on commutative matrices which are defined in finite fields or rings. Thus an algebraic non-linear system of equations is formed. The security of this system will be analyzed. It will be shown that we can use matrix power function in cryptography. We will also be analyzing how does the solution of the system depend on system parameters: the order of matrices and a parameter p which defines a finite group Z_p. We will also briefly discuss the usage of this system in real life and the algebraic properties of the suggested OWF.

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Pedersen, Ørjan. „One-way wave-equation migration for wide-angle propagation in anisotropic media“. Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11338.

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Seismic depth migration is a major component in the search for hydrocarbons. As new prospects for oil and gas often are found in areas with challenging subsurface structures, more advanced methods to find and evaluate these prospects are needed. One-way wave-equation migration provides an appealing approach to be used to create an image of the subsurface. The characteristics of wave propagation can be described through the dispersion relation, relating the vertical and horizontal phase-slowness. In the first part of this thesis, simple and accurate phase-slowness approximations valid for wide-angle propagation in a VTI media are derived. Information from the subsurface might be increased by recording converted wave reflections in addition to pressure waves. The second part of this thesis provides the development of a set of new one-way propagators for imaging steeply dipping and complex structures using converted and pressure waves in a VTI medium. Reliable amplitude information from one-way methods is useful as hydrocarbon indicators in structural imaging and for migration velocity analysis. In the third part of this thesis, a flux-normalized wavefield decomposition is used as a starting point to develop one-way propagators with improved amplitudes. In new exploration areas, salt structures are important examples of subsurface complexity. This poses a challenge for one-way migration methods due to large velocity contrasts between salt and the surrounding sediments. A novel approach using one-way migration operators combined with a lateral windowing construction to limit the impact of errors introduced by large velocity contrasts is developed

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Kasturiratna, Dhanuja. „Assessing the Distributional Assumptions in One-Way Regression Model“. Bowling Green State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1148479945.

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Altaie, Huda. „Nouvelle technique de grilles imbriquées pour les équations de Saint-Venant 2D“. Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4220/document.

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Les écoulements en eau peu profonde se rencontrent dans de nombreuses situations d’intérêts : écoulements de rivières et dans les lacs, mais aussi dans les mers et océans (courants de marée, tsunami, etc.). Ils sont modélisés par un système d’équations aux dérivées partielles, où les inconnues sont la vitesse de l’écoulement et la hauteur d’eau. On peut supposer que la composante verticale de la vitesse est petite devant les composantes horizontales et que ces dernières sont indépendantes de la profondeur. Le modèle est alors donné par les équations de shallow water (SWEs). Cette thèse se concentre sur la conception d’une nouvelle technique d’interaction de plusieurs grilles imbriquées pour modèle en eau peu profonde en utilisant des méthodes numériques. La première partie de cette thèse comprend, La dérivation complète de ces équations à partir des équations de Navier- Stokes est expliquée. Etudier le développement et l’évaluation des méthodes numériques en utilisant des méthodes de différences finies et plusieurs exemples numériques sont appliqués utilisant la condition initiale du niveau gaussien pour 2DSWEs. Dans la deuxième partie de la thèse, nous sommes intéressés à proposer une nouvelle technique d’interaction de plusieurs grilles imbriquées pour résoudre les modèles océaniques en utilisant quatre choix des opérateurs de restriction avec des résultats de haute précision. Notre travail s’est concentré sur la résolution numérique de SWE par grilles imbriquées. A chaque niveau de résolution, nous avons utilisé une méthode classique de différences finies sur une grille C d’Arakawa, avec un schéma de leapfrog complété par un filtre d’Asselin. Afin de pouvoir affiner les calculs dans les régions perturbées et de les alléger dans les zones calmes, nous avons considéré plusieurs niveaux de résolution en utilisant des grilles imbriquées. Ceci permet d’augmenter considérablement le rapport performance de la méthode, à condition de régler efficacement les interactions (spatiales et temporelles) entre les grilles. Dans la troisième partie de cette thèse, plusieurs exemples numéériques sont testés pour 2DSWE avec imbriqués 3:1 et 5:1. Finalement, la quatrième partie de ce travail, certaines applications de grilles imbriquées pour le modèle tsunami sont présentées
Most flows in the rivers, seas, and ocean are shallow water flow in which the horizontal length andvelocity scales are much larger than the vertical ones. The mathematical formulation of these flows, so called shallow water equations (SWEs). These equations are a system of hyperbolic partial differentialequations and they are effective for many physical phenomena in the oceans, coastal regions, riversand canals. This thesis focuses on the design of a new two-way interaction technique for multiple nested grids 2DSWEs using the numerical methods. The first part of this thesis includes, proposing several ways to develop the derivation of shallow water model. The complete derivation of this system from Navier-Stokes equations is explained. Studying the development and evaluation of numerical methods by suggesting new spatial and temporal discretization techniques in a standard C-grid using an explicit finite difference method in space and leapfrog with Robert-Asselin filter in time which are effective for modeling in oceanic and atmospheric flows. Several numerical examples for this model using Gaussian level initial condition are implemented in order to validate the efficiency of the proposed method. In the second part of our work, we are interested to propose a new two-way interaction technique for multiple nested grids to solve ocean models using four choices of higher restriction operators (update schemes) for the free surface elevation and velocities with high accuracy results. Our work focused on the numerical resolution of SWEs by nested grids. At each level of resolution, we used explicit finite differences methods on Arakawa C-grid. In order to be able to refine the calculations in troubled regions and move them into quiet areas, we have considered several levels of resolution using nested grids. This makes it possible to considerably increase the performance ratio of the method, provided that the interactions (spatial and temporal) between the grids are effectively controlled. In the third part of this thesis, several numerical examples are tested to show and verify twoway interaction technique for multiple nested grids of shallow water models can works efficiently over different periods of time with nesting 3:1 and 5:1 at multiple levels. Some examples for multiple nested grids of the tsunami model with nesting 5:1 using moving boundary conditions are tested in the fourth part of this work

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Doc, Jean-Baptiste. „Approximations unidirectionnelles de la propagation acoustique en guide d'ondes irrégulier : application à l'acoustique urbaine“. Thesis, Le Mans, 2012. http://www.theses.fr/2012LEMA1032/document.

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L'environnement urbain est le siège de fortes nuisances sonores notamment générées par les moyens de transport. Afin de lutter contre ces nuisances, la réglementation européenne impose la réalisation de cartographies de bruit. Dans ce contexte, des travaux fondamentaux sont menés autour de la propagation d'ondes acoustiques basses fréquences en milieu urbain. Différents travaux de recherche récents portent sur la mise en œuvre de méthodes ondulatoires pour la propagation d'ondes acoustiques dans de tels milieux. Le coût numérique de ces méthodes limite cependant leur utilisation dans un contexte d'ingénierie. L'objectif de ces travaux de thèse porte sur l'approximation unidirectionnelle de la propagation des ondes, appliquée à l'acoustique urbaine. Cette approximation permet d'apporter des simplifications à l'équation d'onde afin de limiter le temps de calcul lors de sa résolution. La particularité de ce travail de thèse réside dans la prise en compte des variations, continues ou discontinues, de la largeur des rues. Deux formalismes sont utilisés : l'équation parabolique et une approche multimodale. L'approche multimodale sert de support à une étude théorique sur les mécanismes de couplages de modes dans des guides d'ondes irréguliers bidimensionnels. Pour cela, le champ de pression est décomposé en fonction du sens de propagation des ondes à la manière d'une série de Bremmer. La contribution particulière de l'approximation unidirectionnelle est étudiée en fonction des paramètres géométriques du guide d'ondes, ce qui permet de mieux cerner les limites de validité de cette approximation. L'utilisation de l'équation parabolique a pour but une application à l'acoustique urbaine. Une transformation de coordonnées est associée à l'équation parabolique grand angle afin de prendre en compte l'effet de la variation de la section du guide d'ondes. Une méthode de résolution est alors spécifiquement développée et permet une évaluation précise du champ de pression. D'autre part, une méthode de résolution de l'équation parabolique grand angle tridimensionnelle est adaptée à la modélisation de la propagation acoustique en milieu urbain. Cette méthode permet de tenir compte des variations brusques ou continues de la largeur de la rue. Une comparaison avec des mesures sur maquette de rue à échelle réduite permet de mettre en avant les possibilités de la méthode
The urban environment is the seat of loud noise generated by means of transportation. To fight against these nuisances, European legislation requires the achievement of noise maps. In this context, fundamental work is carried around the propagation of acoustic low-frequency waves in urban areas. Several recent research focuses on the implementation of wave methods for acoustic wave propagation in such environments. The computational cost of these methods, however, limits their use in the context of engineering. The objective of this thesis focuses on the one-way approximation of wave propagation, applied to urban acoustics. This approximation allows to make simplifications on the wave equation in order to limit the computation time. The particularity of this thesis lies in the consideration of variations, continuous or discontinuous, of the width of streets. Two formalisms are used: parabolic equation and a multimodal approach. The multimodal approach provides support for a theoretical study on the mode-coupling mechanisms in two-dimensional irregular waveguides. For this, the pressure field is decomposed according to the direction of wave propagation in the manner of a Bremmer series. The specific contribution of the one-way approximation is studied as a function of the geometric parameters of the waveguide, which helps identify the limits of validity of this approximation. Use of the parabolic equation is intended for application to urban acoustic. A coordinate transformation is associated with the wide-angle parabolic-equation in order to take into account the variation effect of the waveguide section. A resolution method is developed specifically and allows an accurate assessment of the pressure field. On the other hand, a solving method of the three-dimensional parabolic-equation is suitable for the modeling of acoustic propagation in urban areas. This method takes into account sudden or continuous variations of the street width. A comparison with measurements on scaled model of street allows to highlight the possibilities of the method

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Bücher zum Thema "One-Way equations"

Lee, Myung W. Finite-difference migration by optimized one-way equations. [Reston, Va.?]: U.S. Dept. of the Interior, Geological Survey, 1985.

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Lee, Myung W. Finite-difference migration by optimized one-way equations. [Reston, Va.?]: U.S. Dept. of the Interior, Geological Survey, 1985.

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Lee, Myung W. Finite-difference migration by optimized one-way equations. [Reston, Va.?]: U.S. Dept. of the Interior, Geological Survey, 1985.

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Lee, Myung W. Finite-difference migration by optimized one-way equations. [Reston, Va.?]: U.S. Dept. of the Interior, Geological Survey, 1985.

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Y, Suh Sang, und Geological Survey (U.S.), Hrsg. Finite-difference migration by optimized one-way equations. [Reston, Va.?]: U.S. Dept. of the Interior, Geological Survey, 1985.

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Trefethen, Lloyd N. Well-posedness of one-way wave equations and absorbing boundary conditions. Hampton, Va: Institute for Computer Applications in Science and Engineering, NASA Langley Research Center, 1985.

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Isett, Philip. A Main Lemma for Continuous Solutions. Princeton University Press, 2017. http://dx.doi.org/10.23943/princeton/9780691174822.003.0005.

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This chapter introduces the Main Lemma that implies the existence of continuous solutions. According to this lemma, there exist constants K and C such that the following holds: Let ϵ‎ > 0, and suppose that (v, p, R) are uniformly continuous solutions to the Euler-Reynolds equations on ℝ x ³, with v uniformly bounded⁷ and suppR ⊆ I x ³ for some time interval. The Main Lemma implies the following theorem: There exist continuous solutions (v, p) to the Euler equations that are nontrivial and have compact support in time. To establish this theorem, one repeatedly applies the Main Lemma to produce a sequence of solutions to the Euler-Reynolds equations. To make sure the solutions constructed in this way are nontrivial and compactly supported, the lemma is applied with e(t) chosen to be any sequence of non-negative functions whose supports are all contained in some finite time interval.

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Ignatyev, Alexander V. DEVELOPMENT OF THE FINITE ELEMENT METHOD IN THE FORM OF THE CLASSICAL MIXED BUILDING MECHANICS METHOD. Thesis for the degree of Doctor of Technical Sciences. Volgograd State Technical University, 2023. http://dx.doi.org/10.12731/dissertation-ignatievav.

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The dissertation states: 1. The main provisions of the theory of the finite element method in the form of a classical mixed method. 2. Methods for obtaining physical and mathematical models of finite elements with mixed unknowns in the main system. 3. Construction of resolving equations based on the obtained mathematical models of finite elements and development of algorithms for their solution. 4. Algorithms for solving problematic problems: accounting for FE displacements as a rigid whole, accounting for rigid inclusions and holes. 5. Features of physical and mathematical models of problems of dynamics and stability of structures and the calculation algorithms that implement them. 6. Physical and mathematical models of reduction methods for lowering the order of large systems of frequency resolving equations. 7. Physical and mathematical models and algorithms for solving geometrically nonlinear problems and problems of calculating structurally nonlinear systems with one-way connections.

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Deruelle, Nathalie, und Jean-Philippe Uzan. The law of gravitation. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198786399.003.0011.

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This chapter embarks on the study of Newton’s law of gravitation. It first discusses gravitational mass and inertial mass, a measure of the ‘resistance’ of the point particle to an applied force. The numerical value of the inertial mass of a body can in principle be obtained from collision experiments by assigning to a reference body a unit inertial mass of one kilogram or, more rigorously, one ‘inertial kilogram’. Next, the chapter considers the ratio of gravitational and inertial masses. It considers that, in the absence of friction, all objects, no matter what their inertial mass, or the nature of their constituents, or the internal energy or cohesive forces of their constituents, fall in the same way in an external gravitational field. Finally, this chapter studies Newton’s gravitational force and field, as well as the Poisson equation and the gravitational Lagrangian.

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Buchteile zum Thema "One-Way equations"

Durran, Dale R. „Beyond the One-Way Wave Equation“. In Texts in Applied Mathematics, 107–71. New York, NY: Springer New York, 1999. http://dx.doi.org/10.1007/978-1-4757-3081-4_3.

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Butscher, Werner. „The Solution of the Seismic One Way Equation on Parallel Computers“. In Lecture Notes in Chemistry, 305–12. Berlin, Heidelberg: Springer Berlin Heidelberg, 1986. http://dx.doi.org/10.1007/978-3-642-51060-1_15.

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Castro, Pablo F., Pedro R. D’Argenio, Ramiro Demasi und Luciano Putruele. „Playing Against Fair Adversaries in Stochastic Games with Total Rewards“. In Computer Aided Verification, 48–69. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-13188-2_3.

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AbstractWe investigate zero-sum turn-based two-player stochastic games in which the objective of one player is to maximize the amount of rewards obtained during a play, while the other aims at minimizing it. We focus on games in which the minimizer plays in a fair way. We believe that these kinds of games enjoy interesting applications in software verification, where the maximizer plays the role of a system intending to maximize the number of “milestones” achieved, and the minimizer represents the behavior of some uncooperative but yet fair environment. Normally, to study total reward properties, games are requested to be stopping (i.e., they reach a terminal state with probability 1). We relax the property to request that the game is stopping only under a fair minimizing player. We prove that these games are determined, i.e., each state of the game has a value defined. Furthermore, we show that both players have memoryless and deterministic optimal strategies, and the game value can be computed by approximating the greatest-fixed point of a set of functional equations. We implemented our approach in a prototype tool, and evaluated it on an illustrating example and an Unmanned Aerial Vehicle case study.

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Pleshkevich, Alexander, Dmitry Vishnevsky, Vadim Lisitsa und Vadim Levchenko. „Parallel Algorithm for One-Way Wave Equation Based Migration for Seismic Imaging“. In Communications in Computer and Information Science, 125–35. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-030-05807-4_11.

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Lytaev, Mikhail S. „Numerical Approximation of the One-Way Helmholtz Equation Using the Differential Evolution Method“. In Computational Science – ICCS 2022, 205–18. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-08751-6_15.

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Lytaev, Mikhail S. „Chebyshev-Type Rational Approximations of the One-Way Helmholtz Equation for Solving a Class of Wave Propagation Problems“. In Computational Science – ICCS 2021, 422–35. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-77961-0_35.

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„Acoustic Two-Way and One-Way Wave Equations“. In Elastic Wave Field Extrapolation, 75–114. Elsevier, 1989. http://dx.doi.org/10.1016/b978-0-444-88472-5.50008-4.

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„Elastic Two-Way and One-Way Wave Equations“. In Elastic Wave Field Extrapolation, 115–57. Elsevier, 1989. http://dx.doi.org/10.1016/b978-0-444-88472-5.50009-6.

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„Tables“. In Heun’s Differential Equations, herausgegeben von A. Ronveaux, 318–21. Oxford University PressOxford, 1995. http://dx.doi.org/10.1093/oso/9780198596950.003.0031.

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Abstract The classification scheme of the hypergeometric class of differential equations. The s-rank multisymbols are given in the boxes; each box represents one type of equation. The boldface arrows between the boxes indicate specialization processes such that in each step to the right the s-rank of one of the singularities of the differential equation is lowered by one-half and the number of irreducible parameters is reduced by one. The lightface arrows indicate confluence processes in which two singularities coalesce and the parameters in the differential equation vary in such a way that the final result does not contain infinite quantities. The s-rank of the singularity resulting from the coalescence is the sum of the s-ranks of the two coalescing singularities. The confluence process decreases the number of irreducible parameters by one. As the table shows, many equations can be reached by different paths from more general ones.

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Zaslavsky, George M. „Chaos and Foundation of Statistical Mechanics“. In Hamiltonian Chaos and Fractional Dynamics, 341–56. Oxford University PressOxford, 2004. http://dx.doi.org/10.1093/oso/9780198526049.003.0022.

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Abstract This is a chapter dedicated to a very special topic of theoretical physics and statistical mechanics: the role of chaos in the foundation of laws of statistical mechanics. Any kind of a physical object, particle, or field can be described by the corresponding equations, Newton equation, Maxwell equations, etc. These equations are reversible in time and fully deterministic, i.e. there exists a unique solution (trajectory) at any time instant t > 0 if some initial conditions are given at t = 0. How, when, and why can an ensemble of a large number of such objects be described in a statistical or probabilistic way, with time irreversible equations, growth of entropy, relaxation to the equilibrium, and other features of the kinetics? The question implies two sides of the problem: one formal and one real.

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Konferenzberichte zum Thema "One-Way equations"

Bleistein, N., und Y. Zhang. „Asymptotically True-amplitude One-way Wave Equations in t“. In 70th EAGE Conference and Exhibition - Workshops and Fieldtrips. European Association of Geoscientists & Engineers, 2008. http://dx.doi.org/10.3997/2214-4609.20147685.

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Chesney, David R., und John M. Kremer. „Generalized Equations for Sprag One-Way Clutch Analysis and Design“. In International Congress & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1998. http://dx.doi.org/10.4271/981092.

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Chesney, David R., und John M. Kremer. „Generalized Equations for Roller One-Way Clutch Analysis and Design“. In SAE International Congress and Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1997. http://dx.doi.org/10.4271/970682.

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Dong, Liangguo, Zhongyi Fan, Hongzhi Wang und Benxin Chi. „Correlation-based reflection waveform inversion by one-way wave equations“. In SEG 2017 Workshop: Full-waveform Inversion and Beyond, Beijing, China, 20-22 November 2017. Society of Exploration Geophysicists, 2017. http://dx.doi.org/10.1190/fwi2017-003.

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Towne, Aaron, und Tim Colonius. „Continued development of the one-way Euler equations: application to jets“. In 20th AIAA/CEAS Aeroacoustics Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2014. http://dx.doi.org/10.2514/6.2014-2903.

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Bleistein, N., Y. Zhang und G. Zhang. „True amplitude one‐way wave equations near smooth caustics: an example“. In SEG Technical Program Expanded Abstracts 2005. Society of Exploration Geophysicists, 2005. http://dx.doi.org/10.1190/1.2148200.

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Cheng Liao, Xuan-Ming Zhong, Jian Fang und Wei Chen. „A Local Absorbing Boundary Condition Based on the One-way Wave Equations“. In 2006 IEEE Antennas and Propagation Society International Symposium. IEEE, 2006. http://dx.doi.org/10.1109/aps.2006.1711168.

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Bleistein, Norman, Yu Zhang und Guanquan Zhang. „Asymptotically true‐amplitude one‐way wave equations int: modeling, migration and inversion“. In SEG Technical Program Expanded Abstracts 2008. Society of Exploration Geophysicists, 2008. http://dx.doi.org/10.1190/1.3059340.

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Kamal, Omar, Georgios Rigas, Matthew T. Lakebrink und Tim Colonius. „Application of the One-Way Navier-Stokes (OWNS) Equations to Hypersonic Boundary Layers“. In AIAA AVIATION 2020 FORUM. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2020. http://dx.doi.org/10.2514/6.2020-2986.

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Bleistein, N., Y. Zhang und G. Zhang. „Uniform Asymptotic Expansions Near Smooth Caustics for True-Amplitude One-Way Wave Equations“. In 67th EAGE Conference & Exhibition. European Association of Geoscientists & Engineers, 2005. http://dx.doi.org/10.3997/2214-4609-pdb.1.g030.

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Berichte der Organisationen zum Thema "One-Way equations"

Ostashev, Vladimir, Michael Muhlestein und D. Wilson. Extra-wide-angle parabolic equations in motionless and moving media. Engineer Research and Development Center (U.S.), September 2021. http://dx.doi.org/10.21079/11681/42043.

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Wide-angle parabolic equations (WAPEs) play an important role in physics. They are derived by an expansion of a square-root pseudo-differential operator in one-way wave equations, and then solved by finite-difference techniques. In the present paper, a different approach is suggested. The starting point is an extra-wide-angle parabolic equation (EWAPE) valid for small variations of the refractive index of a medium. This equation is written in an integral form, solved by a perturbation technique, and transformed to the spectral domain. The resulting split-step spectral algorithm for the EWAPE accounts for the propagation angles up to 90° with respect to the nominal direction. This EWAPE is also generalized to large variations in the refractive index. It is shown that WAPEs known in the literature are particular cases of the two EWAPEs. This provides an alternative derivation of the WAPEs, enables a better understanding of the underlying physics and ranges of their applicability, and opens an opportunity for innovative algorithms. Sound propagation in both motionless and moving media is considered. The split-step spectral algorithm is particularly useful in the latter case since complicated partial derivatives of the sound pressure and medium velocity reduce to wave vectors (essentially, propagation angles) in the spectral domain.

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Fieseler, Kelsey, und Timothy Jacobs. PR-457-14201-R04 Variable NG Composition Effects on LB 2SC Integral Engines. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), September 2018. http://dx.doi.org/10.55274/r0011525.

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The overall goal of this project is to improve upon existing engine control strategies of large bore, fuel-lean natural gas engines in order to increase efficiency and maintain emissions compliance during variable fuel composition events. This will be done by simulating the effects of variable fuels in a natural gas engine, and if necessary, develop engine control methods. Phase III builds upon the work of previous phases by implementing detailed cylinder-level geometry, increasing the number of alkane species in the laminar flame speed and ignition delay solutions, and incorporating a prechamber model into the full-scale engine simulation of a Cooper-Bessemer GMWH-10C. The piston motion and port profiles were calculated from known engine geometry as a way to simulate cylinder compression and expansion as well as cylinder scavenging. The species considered were increased from binary mixtures of methane and ethane to quinary mixtures of methane, ethane, propane, butane, and pentane in order to capture the effects of heavier hydrocarbons. The laminar flame speed and ignition delay equations were developed using the same method utilized in the previous phase, but the laminar flame speed was implemented differently. Two predictive combustion simulations were developed in GT-Power. The first simplifies the combustion chambers into just one open chamber. The second includes the actual cylinder volumes: two small prechambers attached to the main chambers. Both of these models were tuned and validated against experimental data.

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Pessino, Carola, Nadir Altinok und Cristian Chagalj. Allocative Efficiency of Government Spending for Growth in Latin American Countries. Inter-American Development Bank, Juni 2022. http://dx.doi.org/10.18235/0004310.

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There is scant empirical economic research regarding the way that Latin American governments efficiently allocate their spending across different functions to achieve higher growth. While most papers restrict their analysis to the size of government, much less is known about the composition of spending and its implications for long-term growth. This paper sheds light on how allocating expenditures to investment in quality human and physical capital, and avoiding waste on inefficient expenditures, enhance growth in Latin America. This paper uses a novel dataset on physical and human capital and detailed public spending that includes -for the first time- Latin American countries, which is categorized by a cross-classification that provides the breakdown of government expenditure, both, by economic and by functional heads. The database covers 42 countries of the OECD and LAC between 1985 and 2017. There are five main results. First, the estimated growth equations show significant positive effects of the factors of production on growth and plausible convergence rates (about 2 percent). The estimated effect of the physical investment rate is positive and significant with a long-run elasticity of 1.2. Second, while the addition of years of education as a proxy for human capital tends to have no effect on growth, the addition of a new variable that measures quality-adjusted years of schooling as a proxy for human capital turns out to have a positive and significant effect across all specifications with a long-run elasticity of 1.1. However, if public spending on education (excluding infrastructure spending) is added to the factor specification, growth is not affected. This is mainly because, once quality is considered, spending more on teacher salaries has no effect on student outcomes. Therefore, the key is to increase quality, not just school performance or education spending. Third, both physical and human capital are equally important for growth: the effect of increasing one standard deviation of physical capital or human capital statistically has the same impact on economic growth. Fourth, increasing public investment spending (holding public spending constant) is positive and significant for growth (a 1% increase in public investment would increase the long-term GDP per capita by about 0.3 percent), in addition to the effect of the private investment rate. However, the effect of public spending on payroll, pensions and subsidies does not contribute to economic growth. Fifth, the overall effect of the size of public spending on economic growth is negative in most specifications. An increase in the size of government by about 1 percentage point would decrease 4.1 percent the long-run GDP per capita, but the more effective the government is, the less harmful the size of government is for long-term growth.

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Kayo, Genku, und Nobue Suzuki. Measurement of air change behaviour at Finnish apartment rooms. Department of the Built Environment, 2023. http://dx.doi.org/10.54337/aau541579038.

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While the expectation for natural ventilation is increasing under the context of COVID-19, fresh air at residential houses in Finland is basically guaranteed by mechanical ventilation systems. It means that natural ventilation is not considered as an available potential of ventilation in Finnish building regulation. Even if the mechanical ventilation system handles the air quality, the natural ventilation by window opening is expected to be a supportive measure. However, there is not enough measured data about how much air change is fulfilled by window opening. The article describes the evaluation of fresh air accessibility by window openings at six Finnish apartments. To understand the behaviour of air change, CO2 mass balance equation model was applied. The results of summer season clarified that the actual number of air changes are 085 to 1.54 times per hour with one-side opening. The CO2 mass balance model for apartments, which is a kind of tracer gas decay method, is an effective way to estimate the actual number of air changes without preventing occupants’ daily living. Since some buildings, such as residential, school, churches, are affected by the moisture problems, the management of moisture behaviour by both natural and mechanical ventilation is essential.

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HEFNER, Robert. IHSAN ETHICS AND POLITICAL REVITALIZATION Appreciating Muqtedar Khan’s Islam and Good Governance. IIIT, Oktober 2020. http://dx.doi.org/10.47816/01.001.20.

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Ours is an age of pervasive political turbulence, and the scale of the challenge requires new thinking on politics as well as public ethics for our world. In Western countries, the specter of Islamophobia, alt-right populism, along with racialized violence has shaken public confidence in long-secure assumptions rooted in democracy, diversity, and citizenship. The tragic denouement of so many of the Arab uprisings together with the ascendance of apocalyptic extremists like Daesh and Boko Haram have caused an even greater sense of alarm in large parts of the Muslim-majority world. It is against this backdrop that M.A. Muqtedar Khan has written a book of breathtaking range and ethical beauty. The author explores the history and sociology of the Muslim world, both classic and contemporary. He does so, however, not merely to chronicle the phases of its development, but to explore just why the message of compassion, mercy, and ethical beauty so prominent in the Quran and Sunna of the Prophet came over time to be displaced by a narrow legalism that emphasized jurisprudence, punishment, and social control. In the modern era, Western Orientalists and Islamists alike have pushed the juridification and interpretive reification of Islamic ethical traditions even further. Each group has asserted that the essence of Islam lies in jurisprudence (fiqh), and both have tended to imagine this legal heritage on the model of Western positive law, according to which law is authorized, codified, and enforced by a leviathan state. “Reification of Shariah and equating of Islam and Shariah has a rather emaciating effect on Islam,” Khan rightly argues. It leads its proponents to overlook “the depth and heights of Islamic faith, mysticism, philosophy or even emotions such as divine love (Muhabba)” (13). As the sociologist of Islamic law, Sami Zubaida, has similarly observed, in all these developments one sees evidence, not of a traditionalist reassertion of Muslim values, but a “triumph of Western models” of religion and state (Zubaida 2003:135). To counteract these impoverishing trends, Khan presents a far-reaching analysis that “seeks to move away from the now failed vision of Islamic states without demanding radical secularization” (2). He does so by positioning himself squarely within the ethical and mystical legacy of the Qur’an and traditions of the Prophet. As the book’s title makes clear, the key to this effort of religious recovery is “the cosmology of Ihsan and the worldview of Al-Tasawwuf, the science of Islamic mysticism” (1-2). For Islamist activists whose models of Islam have more to do with contemporary identity politics than a deep reading of Islamic traditions, Khan’s foregrounding of Ihsan may seem unfamiliar or baffling. But one of the many achievements of this book is the skill with which it plumbs the depth of scripture, classical commentaries, and tasawwuf practices to recover and confirm the ethic that lies at their heart. “The Quran promises that God is with those who do beautiful things,” the author reminds us (Khan 2019:1). The concept of Ihsan appears 191 times in 175 verses in the Quran (110). The concept is given its richest elaboration, Khan explains, in the famous hadith of the Angel Gabriel. This tradition recounts that when Gabriel appeared before the Prophet he asked, “What is Ihsan?” Both Gabriel’s question and the Prophet’s response make clear that Ihsan is an ideal at the center of the Qur’an and Sunna of the Prophet, and that it enjoins “perfection, goodness, to better, to do beautiful things and to do righteous deeds” (3). It is this cosmological ethic that Khan argues must be restored and implemented “to develop a political philosophy … that emphasizes love over law” (2). In its expansive exploration of Islamic ethics and civilization, Khan’s Islam and Good Governance will remind some readers of the late Shahab Ahmed’s remarkable book, What is Islam? The Importance of Being Islamic (Ahmed 2016). Both are works of impressive range and spiritual depth. But whereas Ahmed stood in the humanities wing of Islamic studies, Khan is an intellectual polymath who moves easily across the Islamic sciences, social theory, and comparative politics. He brings the full weight of his effort to conclusion with policy recommendations for how “to combine Sufism with political theory” (6), and to do so in a way that recommends specific “Islamic principles that encourage good governance, and politics in pursuit of goodness” (8).

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