Academic literature on the topic 'Operator split'
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Journal articles on the topic "Operator split"
1
Zhao, Jing, and Hang Zhang. "Solving Split Common Fixed-Point Problem of Firmly Quasi-Nonexpansive Mappings without Prior Knowledge of Operators Norms." Abstract and Applied Analysis 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/389689.
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Very recently, Moudafi introduced alternating CQ-algorithms and simultaneous iterative algorithms for the split common fixed-point problem concerned two bounded linear operators. However, to employ Moudafi’s algorithms, one needs to know a prior norm (or at least an estimate of the norm) of the bounded linear operators. To estimate the norm of an operator is very difficult, if it is not an impossible task. It is the purpose of this paper to introduce a viscosity iterative algorithm with a way of selecting the stepsizes such that the implementation of the algorithm does not need any prior information about the operator norms. We prove the strong convergence of the proposed algorithms for split common fixed-point problem governed by the firmly quasi-nonexpansive operators. As a consequence, we obtain strong convergence theorems for split feasibility problem and split common null point problems of maximal monotone operators. Our results improve and extend the corresponding results announced by many others.
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Bandrauk, André D., and Hai Shen. "Higher order exponential split operator method for solving time-dependent Schrödinger equations." Canadian Journal of Chemistry 70, no. 2 (February 1, 1992): 555–59. http://dx.doi.org/10.1139/v92-078.
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A new method of splitting exponential operators is proposed for the exponential form of the operator solution to the time-dependent Schrödinger equation. The method is shown to hold for any desired accuracy in the time increment. A comparison of different algorithms is made as a function of accuracy and computation time. Keywords: splitting operator, Fast Fourier Transform (FFT), Schrödinger equations.
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Gupta, Nishu, Mihai Postolache, Ashish Nandal, and Renu Chugh. "A Cyclic Iterative Algorithm for Multiple-Sets Split Common Fixed Point Problem of Demicontractive Mappings without Prior Knowledge of Operator Norm." Mathematics 9, no. 4 (February 13, 2021): 372. http://dx.doi.org/10.3390/math9040372.
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The aim of this paper is to formulate and analyze a cyclic iterative algorithm in real Hilbert spaces which converges strongly to a common solution of fixed point problem and multiple-sets split common fixed point problem involving demicontractive operators without prior knowledge of operator norm. Significance and range of applicability of our algorithm has been shown by solving the problem of multiple-sets split common null point, multiple-sets split feasibility, multiple-sets split variational inequality, multiple-sets split equilibrium and multiple-sets split monotone variational inclusion.
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Jailoka, Pachara, and Suthep Suantai. "Viscosity approximation methods for split common fixed point problems without prior knowledge of the operator norm." Filomat 34, no. 3 (2020): 761–77. http://dx.doi.org/10.2298/fil2003761j.
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In this work, we study the split common fixed point problem which was first introduced by Censor and Segal [14]. We introduce an algorithm based on the viscosity approximation method without prior knowledge of the operator norm by selecting the stepsizes in the same adaptive way as L?opez et al. [22] for solving the problem for two attracting quasi-nonexpansive operators in real Hilbert spaces. A strong convergence result of the proposed algorithm is established under some suitable conditions. We also modify our algorithm to extend to the class of demicontractive operators and the class of hemicontractive operators, and obtain strong convergence results. Moreover, we apply our main result to other split problems, that is, the split feasibility problem and the split variational inequality problem. Finally, a numerical result is also given to illustrate the convergence behavior of our algorithm.
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Li, Meixia, Xueling Zhou, and Haitao Che. "Mixed Simultaneous Iterative Algorithms for the Extended Multiple-Set Split Equality Common Fixed-Point Problem with Lipschitz Quasi-Pseudocontractive Operators." Mathematical Problems in Engineering 2019 (March 7, 2019): 1–10. http://dx.doi.org/10.1155/2019/3606294.
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In this paper, we study a kind of extended multiple-set split equality common fixed-point problem with Lipschitz quasi-pseudocontractive operators, which is an extension of multiple-set split equality common fixed-point problem with quasi-nonexpansive operator. We propose two mixed simultaneous iterative algorithms, in which the selecting of the stepsize does not need any priori information about the operator norms. Furthermore, we prove that the sequences generated by the mixed simultaneous iterative algorithms converge weakly to the solution of this problem. Some numerical results are shown to illustrate the feasibility and efficiency of the proposed algorithms.
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Yevick, D., W. Bardyszewski, B. Hermansson, and M. Glasner. "Split-operator electric field reflection techniques." IEEE Photonics Technology Letters 3, no. 6 (June 1991): 527–29. http://dx.doi.org/10.1109/68.91023.
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Kitkuan, Duangkamon, Poom Kumam, Vasile Berinde, and Anantachai Padcharoen. "Adaptive algorithm for solving the SCFPP of demicontractive operators without a priori knowledge of operator norms." Analele Universitatii "Ovidius" Constanta - Seria Matematica 27, no. 3 (December 1, 2019): 153–75. http://dx.doi.org/10.2478/auom-2019-0039.
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AbstractIn this paper, we study the split common fixed point problem in Hilbert spaces. We find a common solution of the split common fixed point problem for two demicontractive operators without a priori knowledge of operator norms. A strong convergence theorem is obtained under some additional conditions and numerical examples are included to illustrate the applications in signal compressed sensing and image restoration.
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DATTA, ALAKABHA, and XINMIN ZHANG. "VACUUM STABILITY IN SPLIT SUSY AND LITTLE HIGGS MODELS." International Journal of Modern Physics A 21, no. 11 (April 30, 2006): 2431–45. http://dx.doi.org/10.1142/s0217751x06029521.
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We study the stability of the effective Higgs potential in the split supersymmetry and Little Higgs models. In particular, we study the effects of higher dimensional operators in the effective potential on the Higgs mass predictions. We find that the size and sign of the higher dimensional operators can significantly change the Higgs mass required to maintain vacuum stability in Split SUSY models. In the Little Higgs models the effects of higher dimensional operators can be large because of a relatively lower cutoff scale. Working with a specific model we find that a contribution from the higher dimensional operator with coefficient of O(1) can destabilize the vacuum.
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Čiegis, Raimondas, Aleksas Mirinavičius, and Mindaugas Radziunas. "Comparison of Split Step Solvers for Multidimensional Schrödinger Problems." Computational Methods in Applied Mathematics 13, no. 2 (April 1, 2013): 237–50. http://dx.doi.org/10.1515/cmam-2013-0004.
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Abstract. This paper presents the analysis of the split step solvers for multidimensional Schrödinger problems. The second-order symmetrical splitting techniques are applied. The standard operator splitting is used to split the linear diffraction and reaction/potential processes. The dimension splitting exploits the commuting property of one-dimensional discrete diffraction operators. Alternating Direction Implicit (ADI) and Locally One-Dimensional (LOD) algorithms are constructed and stability is investigated for two- and three-dimensional problems. Compact high-order approximations are applied to discretize diffraction operators. Results of numerical experiments are presented and convergence of finite difference schemes is investigated.
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Ristow, Dietrich, and Thomas Rühl. "Fourier finite‐difference migration." GEOPHYSICS 59, no. 12 (December 1994): 1882–93. http://dx.doi.org/10.1190/1.1443575.
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Many existing migration schemes cannot simultaneously handle the two most important problems of migration: imaging of steep dips and imaging in media with arbitrary velocity variations in all directions. For example, phase‐shift (ω, k) migration is accurate for nearly all dips but it is limited to very simple velocity functions. On the other hand, finite‐difference schemes based on one‐way wave equations consider arbitrary velocity functions but they attenuate steeply dipping events. We propose a new hybrid migration method, named “Fourier finite‐difference migration,” wherein the downward‐continuation operator is split into two downward‐continuation operators: one operator is a phase‐shift operator for a chosen constant background velocity, and the other operator is an optimized finite‐difference operator for the varying component of the velocity function. If there is no variation of velocity, then only a phase‐shift operator will be applied automatically. On the other hand, if there is a strong variation of velocity, then the phase‐shift component is suppressed and the optimized finite‐difference operator will be fully applied. The cascaded application of phase‐shift and finite‐difference operators shows a better maximum dip‐angle behavior than the split‐step Fourier migration operator. Depending on the macro velocity model, the Fourier finite‐difference migration even shows an improved performance compared to conventional finite‐difference migration with one downward‐continuation step. Finite‐difference migration with two downward‐continuation steps is required to reach the same migration performance, but this is achieved with about 20 percent higher computation costs. The new cascaded operator of the Fourier finite‐difference migration can be applied to arbitrary velocity functions and allows an accurate migration of steeply dipping reflectors in a complex macro velocity model. The dip limitation of the cascaded operator depends on the variation of the velocity field and, hence, is velocity‐adaptive.
Dissertations / Theses on the topic "Operator split"
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Braga, João Philipe Macedo. "Técnica Split Operator em Coordenadas Generalizadas." reponame:Repositório Institucional da UFC, 2010. http://www.repositorio.ufc.br/handle/riufc/7721.
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BRAGA, João Philipe Macedo. Técnica split operator em coordenadas generalizadas. 2010. 84 f. Dissertação (Mestrado em Física) - Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2010.Submitted by francisco lima (admir@ufc.br) on 2014-03-18T12:27:21Z No. of bitstreams: 1 2010_dis_jpmbraga.pdf: 953031 bytes, checksum: 788517c406c012d339bc8fe1d2fb7079 (MD5)
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Quantum mechanics plays a fundamental role in the description and understanding of the natural phenomena. Actually, the phenomena that take place in atomic and subatomic scale can not be well explained without the quantum mechanics approach. Furthermore, there are a lot of phenomena in macroscopic scale that reveals the quantum behavior of nature. In this sense, we can say that quantum mechanics is fundamental for the understanding of all natural phenomena. In Quantum Mechanics the state of a particle is mathematically described by the wave function Ψ(r,t) and its time evolution is governed by time-dependent Schrödinger equation. Thus, we can state that the fundamental problem of quantum mechanics is to solve the Schrödinger Equation in an arbitrary situation. In this work, we study a numerical technique to solve the time-dependent and time-independent Schrödinger Equation known as Split Operator technique. This aproach uses approximations for the exponencial of sum of operators that do not commute in order to implement the time-evolution operator. It makes possible to reduce the solution of the Schrödinger equation to a successive processes of multiplication and solution of tridiagonal system of linear equations. It can be easily performed using a computer. The technique was studied in detail using cartesian coordinates, and we also explained how to use the technique with periodic or finite boundary conditions. We make use this technique to study the behavior of an electron subjected to a random potential. In this situation we face the Anderson Localization phenomena. Furthermore, we developed the Split Operator technique using generalized coordinates, and studied the problem of an electron confined to a cylinder surface. It was verified that the numerical results agree with the analytical ones. So we can conclude that the Split Operator technique using generalized coordinates produce reliable results.
A mecânica quântica desempenha um papel fundamental na descrição e entendimento dos fenômenos naturais. De fato, os fenômenos que ocorrem em uma escala muito pequena (atômica ou sub-atômica) não podem ser corretamente explicados fora do contexto da mecânica quântica. Além disso, existem muitos fenômenos em escala macroscópica que revelam o comportamento quântico da natureza. Nesse sentido, podemos dizer que a mecânica quântica é a base de todo nosso atual conhecimento sobre os fenômenos naturais. O estado de uma partícula em quântica é descrito matematicamente pela sua função de onda Ψ(r,t) e a evolução temporal de Ψ(r,t) é governada pela Equação de Schrödinger dependente do tempo. Dessa forma, podemos enunciar que o problema fundamental da mecânica quântica consiste em solucionar a Equação de Schrödinger numa situação arbitrária. Neste trabalho, estudamos uma técnica numérica de solução da Equação de Schrödinger dependente ou independente do tempo conhecida como Split Operator. Essa técnica utiliza formas aproximadas para a exponencial da soma de operadores que não comutam para implementar o operador evolução temporal, permitindo reduzir o processo de solução da Equação de Schrödinger a sucessivos processos de simples multiplicação e de solução de sistemas de equações lineares tridiagonais, que podem ser facilmente realizados por um computador. O formalismo da técnica em coordenadas cartesianas foi estudado em detalhes, onde mostramos como aplicá-lo para sistemas com condições de com torno periódicas ou com condições de contorno finitas. Utilizamos essa forma da técnica para estudar o comportamento de um elétron confinado numa região de energia potencial aleatória, onde nos deparamos com o fenômeno de Localização de Anderson. Além disso, desenvolvemos a técnica Split Operator em coordenadas generalizadas, aplicando-a para estudar o problema de um elétron confinado na superfície de um cilindro. Os resultados obtidos numericamente concordam muito bem com os resultados obtidos analiticamente, mostrando que a técnica Split Operator em coordenadas generalizadas nos leva a resultados confiáveis.
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Braga, JoÃo Philipe Macedo. "TÃcnica Split Operator em Coordenadas Generalizadas." Universidade Federal do CearÃ, 2010. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=5493.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoA mecÃnica quÃntica desempenha um papel fundamental na descriÃÃo e entendimento dos fenÃmenos naturais. De fato, os fenÃmenos que ocorrem em uma escala muito pequena (atÃmica ou sub-atÃmica) nÃo podem ser corretamente explicados fora do contexto da mecÃnica quÃntica. AlÃm disso, existem muitos fenÃmenos em escala macroscÃpica que revelam o comportamento quÃntico da natureza. Nesse sentido, podemos dizer que a mecÃnica quÃntica à a base de todo nosso atual conhecimento sobre os fenÃmenos naturais. O estado de uma partÃcula em quÃntica à descrito matematicamente pela sua funÃÃo de onda Ψ(r,t) e a evoluÃÃo temporal de Ψ(r,t) à governada pela EquaÃÃo de SchrÃdinger dependente do tempo. Dessa forma, podemos enunciar que o problema fundamental da mecÃnica quÃntica consiste em solucionar a EquaÃÃo de SchrÃdinger numa situaÃÃo arbitrÃria. Neste trabalho, estudamos uma tÃcnica numÃrica de soluÃÃo da EquaÃÃo de SchrÃdinger dependente ou independente do tempo conhecida como Split Operator. Essa tÃcnica utiliza formas aproximadas para a exponencial da soma de operadores que nÃo comutam para implementar o operador evoluÃÃo temporal, permitindo reduzir o processo de soluÃÃo da EquaÃÃo de SchrÃdinger a sucessivos processos de simples multiplicaÃÃo e de soluÃÃo de sistemas de equaÃÃes lineares tridiagonais, que podem ser facilmente realizados por um computador. O formalismo da tÃcnica em coordenadas cartesianas foi estudado em detalhes, onde mostramos como aplicÃ-lo para sistemas com condiÃÃes de com torno periÃdicas ou com condiÃÃes de contorno finitas. Utilizamos essa forma da tÃcnica para estudar o comportamento de um elÃtron confinado numa regiÃo de energia potencial aleatÃria, onde nos deparamos com o fenÃmeno de LocalizaÃÃo de Anderson. AlÃm disso, desenvolvemos a tÃcnica Split Operator em coordenadas generalizadas, aplicando-a para estudar o problema de um elÃtron confinado na superfÃcie de um cilindro. Os resultados obtidos numericamente concordam muito bem com os resultados obtidos analiticamente, mostrando que a tÃcnica Split Operator em coordenadas generalizadas nos leva a resultados confiÃveis.
Quantum mechanics plays a fundamental role in the description and understanding of the natural phenomena. Actually, the phenomena that take place in atomic and subatomic scale can not be well explained without the quantum mechanics approach. Furthermore, there are a lot of phenomena in macroscopic scale that reveals the quantum behavior of nature. In this sense, we can say that quantum mechanics is fundamental for the understanding of all natural phenomena. In Quantum Mechanics the state of a particle is mathematically described by the wave function Ψ(r,t) and its time evolution is governed by time-dependent SchrÃdinger equation. Thus, we can state that the fundamental problem of quantum mechanics is to solve the SchrÃdinger Equation in an arbitrary situation. In this work, we study a numerical technique to solve the time-dependent and time-independent SchrÃdinger Equation known as Split Operator technique. This aproach uses approximations for the exponencial of sum of operators that do not commute in order to implement the time-evolution operator. It makes possible to reduce the solution of the SchrÃdinger equation to a successive processes of multiplication and solution of tridiagonal system of linear equations. It can be easily performed using a computer. The technique was studied in detail using cartesian coordinates, and we also explained how to use the technique with periodic or finite boundary conditions. We make use this technique to study the behavior of an electron subjected to a random potential. In this situation we face the Anderson Localization phenomena. Furthermore, we developed the Split Operator technique using generalized coordinates, and studied the problem of an electron confined to a cylinder surface. It was verified that the numerical results agree with the analytical ones. So we can conclude that the Split Operator technique using generalized coordinates produce reliable results.
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Silva, Francisco Wellery Nunes. "Transporte eletrônico em semicondutores porosos baseado na equação de Schrodinger dependente do tempo." reponame:Repositório Institucional da UFC, 2012. http://www.repositorio.ufc.br/handle/riufc/11710.
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SILVA, Francisco Wellery Nunes. Transporte eletrônico em semicondutores porosos baseado na equação de Schrodinger dependente do tempo. 2012. 77 f. Dissertação (Mestrado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2012.Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-04-23T21:11:22Z No. of bitstreams: 1 2012_dis_fwnsilva.pdf: 12829801 bytes, checksum: 1fca3d2dc15fc07961d7231c6087fe50 (MD5)
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We propose in this work a theoretical study, of the properties of a electronic pulse, injected under a external bias, on a porous silicon layer, so that we could define fundamentally the shape of T X V and R X V curves, where T is the transmission coefficient and R is the reflection coefficient of the wave packet, trough the porous region. With this, we could make a simple calculation and obtain information about the electrical current in this material, using the very simple model I=Q/t, where we defined the time of transmission, as the time interval necessary for the electronic pulse to be consumed completely. This kind of approach is already known in the literature, propose by Lebedev and co-workers (1998). Using the definition of charge carrier mobility, we obtained information about it, since the principal aim of this work is the electronic transport in this kind of material, that despite a strong research on porous silicon, since the beginning of the nineties, the transport properties still remains a relatively unexplored area. The major incentive for this study is due to the strong possibility of application of this material in new optoelectronic devices such as LEDs. Along the development of this dissertation, we applied well known techniques for the computational modelling such as effective mass theory, for example, associated with methods like the periodic boundary conditions, and the absorbing boundary conditions. Treating of a quantum system, we begin all the work solving the time dependent Schröedinger equation. To do this task, we have used the numerical method known as Split-Operator, in order to obtain the solutions for this equation. Initially, the calculations in this dissertation where based in an isotropic effective mass, in order to optimise the calculation parameters. After this, we made calculations using an anisotropic effective mass for the different valleys of silicon. All these things leads us to believe that this work have a great importance regarding the contribution to the understanding of transport in electronic systems based on porous silicon, to maintain for some time the applications of this kind of material that was so revolutionary in the twentieth.
Neste trabalho, propomos um uma pesquisa teórica onde estudamos as propriedades de um pulso eletrônico em uma camada de silício poroso, injetado sob uma certa voltagem externa V. Desta forma, podemos definir fundamentalmente a forma das curvas T X V e R X V, onde T é o coeficiente de transmissão e R é o coeficiente de reflexão do pacote de onda através da região porosa. Aliado a estes dados, podemos fazer um cálculo simples e obter informações a respeito da corrente elétrica que atravessa o material, utilizando o modelo I=Q/t, onde definimos o tempo como o intervalo necessário para que o pulso seja consumido completamente, como proposto por Lebedev e colaboradores (1998). Utilizando a definição para mobilidade de portadores de carga, obtivemos informações sobre a mesma, pois este trabalho foca-se principalmente no estudo do transporte eletrônico neste tipo de material poroso, que apesar de um estudo intenso em silício poroso desde o início da década de noventa, as propriedades de transporte ainda permanecem um pouco inexploradas. O principal incentivo para que estudemos este material é devido à grande possibilidade da criação de dispositivos em opto-eletrônica tais como LEDs (Light Emissor Diode). Ao longo do desenvolvimento, empregamos técnicas já bem conhecidas para a modelagem de semicondutores, como a teoria da massa efetiva, por exemplo, associadas a técnicas de modelagem computacional, como o emprego de condições periódicas de contorno e condições de contorno absorvente. Por se tratar de um sistema quântico, tudo parte da solução da equação de Schrödinger dependente do tempo, e para executar esta tarefa fizemos uso de um método numérico conhecido como Split-Operator. Assim obtemos as soluções para a equação. Inicialmente, os cálculos realizados neste trabalho foram baseados em uma massa efetiva isotrópica, a fim de otimizar os parâmetros de cálculo, e só em seguida foram feitos cálculos baseando-se em massa efetiva anisotrópica para os diversos vales do silício poroso. Tudo isto nos leva a crer que este trabalho possui uma grande importância no que diz respeito à contribuição para o entendimento do transporte eletrônico em sistemas baseados em silício poroso, de forma a manter por mais algum tempo a aplicação deste tipo de material que foi tão revolucionário no século XX.
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Gonzalez, Csaszar Eduardo. "Analysis of optical propagation in isotropic nonlinear devices by the finite element method." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244741.
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Silva, Francisco Wellery Nunes. "Transporte eletrÃnico em semicondutores porosos baseado na equaÃÃo de Schrodinger dependente do tempo." Universidade Federal do CearÃ, 2012. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7337.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoNeste trabalho, propomos um uma pesquisa teÃrica onde estudamos as propriedades de um pulso eletrÃnico em uma camada de silÃcio poroso, injetado sob uma certa voltagem externa V. Desta forma, podemos definir fundamentalmente a forma das curvas T X V e R X V, onde T à o coeficiente de transmissÃo e R à o coeficiente de reflexÃo do pacote de onda atravÃs da regiÃo porosa. Aliado a estes dados, podemos fazer um cÃlculo simples e obter informaÃÃes a respeito da corrente elÃtrica que atravessa o material, utilizando o modelo I=Q/t, onde definimos o tempo como o intervalo necessÃrio para que o pulso seja consumido completamente, como proposto por Lebedev e colaboradores (1998). Utilizando a definiÃÃo para mobilidade de portadores de carga, obtivemos informaÃÃes sobre a mesma, pois este trabalho foca-se principalmente no estudo do transporte eletrÃnico neste tipo de material poroso, que apesar de um estudo intenso em silÃcio poroso desde o inÃcio da dÃcada de noventa, as propriedades de transporte ainda permanecem um pouco inexploradas. O principal incentivo para que estudemos este material à devido à grande possibilidade da criaÃÃo de dispositivos em opto-eletrÃnica tais como LEDs (Light Emissor Diode). Ao longo do desenvolvimento, empregamos tÃcnicas jà bem conhecidas para a modelagem de semicondutores, como a teoria da massa efetiva, por exemplo, associadas a tÃcnicas de modelagem computacional, como o emprego de condiÃÃes periÃdicas de contorno e condiÃÃes de contorno absorvente. Por se tratar de um sistema quÃntico, tudo parte da soluÃÃo da equaÃÃo de SchrÃdinger dependente do tempo, e para executar esta tarefa fizemos uso de um mÃtodo numÃrico conhecido como Split-Operator. Assim obtemos as soluÃÃes para a equaÃÃo. Inicialmente, os cÃlculos realizados neste trabalho foram baseados em uma massa efetiva isotrÃpica, a fim de otimizar os parÃmetros de cÃlculo, e sà em seguida foram feitos cÃlculos baseando-se em massa efetiva anisotrÃpica para os diversos vales do silÃcio poroso. Tudo isto nos leva a crer que este trabalho possui uma grande importÃncia no que diz respeito à contribuiÃÃo para o entendimento do transporte eletrÃnico em sistemas baseados em silÃcio poroso, de forma a manter por mais algum tempo a aplicaÃÃo deste tipo de material que foi tÃo revolucionÃrio no sÃculo XX.
We propose in this work a theoretical study, of the properties of a electronic pulse, injected under a external bias, on a porous silicon layer, so that we could define fundamentally the shape of T X V and R X V curves, where T is the transmission coefficient and R is the reflection coefficient of the wave packet, trough the porous region. With this, we could make a simple calculation and obtain information about the electrical current in this material, using the very simple model I=Q/t, where we defined the time of transmission, as the time interval necessary for the electronic pulse to be consumed completely. This kind of approach is already known in the literature, propose by Lebedev and co-workers (1998). Using the definition of charge carrier mobility, we obtained information about it, since the principal aim of this work is the electronic transport in this kind of material, that despite a strong research on porous silicon, since the beginning of the nineties, the transport properties still remains a relatively unexplored area. The major incentive for this study is due to the strong possibility of application of this material in new optoelectronic devices such as LEDs. Along the development of this dissertation, we applied well known techniques for the computational modelling such as effective mass theory, for example, associated with methods like the periodic boundary conditions, and the absorbing boundary conditions. Treating of a quantum system, we begin all the work solving the time dependent SchrÃedinger equation. To do this task, we have used the numerical method known as Split-Operator, in order to obtain the solutions for this equation. Initially, the calculations in this dissertation where based in an isotropic effective mass, in order to optimise the calculation parameters. After this, we made calculations using an anisotropic effective mass for the different valleys of silicon. All these things leads us to believe that this work have a great importance regarding the contribution to the understanding of transport in electronic systems based on porous silicon, to maintain for some time the applications of this kind of material that was so revolutionary in the twentieth.
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Keller, Wolfgang Verfasser], and Volker [Gutachter] [Kaibel. "Tightening the Chvátal and split operator via low-codimensional lineality spaces / Wolfgang Keller ; Gutachter: Volker Kaibel." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2019. http://d-nb.info/1220036455/34.
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Keller, Wolfgang [Verfasser], and Volker [Gutachter] Kaibel. "Tightening the Chvátal and split operator via low-codimensional lineality spaces / Wolfgang Keller ; Gutachter: Volker Kaibel." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2019. http://d-nb.info/1220036455/34.
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Perea-Estrada, Hugo. "Development, Verification, and Evaluation of a Solute Transport Model in Surface Irrigation." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1322%5F1%5Fm.pdf&type=application/pdf.
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Bezerra, Anibal Thiago. "Modelagem computacional de estruturas de poços quânticos semicondutores para dispositivos optoeletrônicos e spintrônicos." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/4969.
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Previous issue date: 2014-01-29Universidade Federal de Sao Carlos
In the present thesis, we realize a computational modeling of semiconductor structures based on multiple quantum wells with filter barriers and on quantum wells with semiconductor diluted magnetic layers. We numerically solve the time-dependent Schrödinger s equation within the effective mass approximation, using the Split Operator method. Through the time evolved wave functions we access the dynamics quantities as the light assisted couplings of the states, in which the light is described by the inclusion of an oscillating electric field in the Hamiltonian. Then we determine the probabilities of absorption, oscillator strengths of the intersubband transitions induced by the light. Moreover we analyze the transmission probabilities and, in special, the system s photocurrent. The eigenstates and the eigenfunctions of the stationary states are also obtained within the method by simply making an imaginary time evolution. In the first work, the photocurrent of a multiple quantum well structure with filter barriers modulating the continuum above the wells was analyzed as a function of the applied bias. We find out an interesting dependence of the photocurrent with the applied field, as a differential negative photoconductance controlled by the field. We attribute this negative conductance to the interaction between the localized and extended states in the continuum, expressed by anticrossings between these states and the enhancement of the photocurrent at the crossings by the Landau-Zener-Stückelberg-Majorama like transitions. In the second work, it was evaluated the spin polarized photocurrent arising from quantum well s structures of GaMnAs, under light, electric and magnetic fields of few teslas. The study shows the existence of spectral domains in the THz ranges for which the proposed structure is strongly spin selective. For such photon frequencies, the photocurrent is spin polarized and the application of the external electric field reverts the polarization s signal. This behavior suggests the possibility of conveniently simple switching mechanisms. The physics underlying these results is studied and understood in terms of the spin-dependent coupling strengths emerging from the particular potential profiles of the heterostructures. We present two additional works related to the main ones. In the first additional one, we evaluated the dark current of the multiple quantum well structure with and without filter barriers. For doing this, we add totally the transmission probability through the structure in the Levine s model for the dark current. We observe that dark current is considerably reduced for the structure with the filter barriers when compared to the structure without these barriers. In the second additional work, we calculate the photocurrent in a ZnMnSe structure. We observe the generation of a spin polarized photocurrent controlled by the external electric field, as in the case of the GaMnAs structures.
Na presente tese, realizamos a modelagem computacional de estruturas semicondutoras baseadas em poços quânticos múltiplos com barreiras de filtro e em poços quânticos com camadas de material semicondutor magnético diluído. Para tanto, resolvemos numericamente a equação de Schrödinger dependente do tempo na aproximação de massa efetiva, por meio da evolução temporal das funções de onda do sistema, utilizando o chamado método do Split- Operator. Com as funções de onda evoluídas no tempo temos acesso às variáveis dinâmicas do sistema, como os acoplamentos entre os estados pela presença de luz, descrita na forma de um campo elétrico oscilante. Determinamos assim as probabilidades de absorção, forças de oscilador das transições intersubbandas geradas por essa excitação com luz, as probabilidades de transmissão através da estrutura e, em especial, o espectro de fotocorrente proveniente desses sistemas semicondutores. As autofunções e as autoenergias dos estados estacionários dos sistemas são obtidas pelo mesmo método realizando a evolução em tempo imaginário. No primeiro trabalho, a fotocorrente da estrutura de poços quânticos múltiplos com barreiras de filtro foi analisada em função do campo elétrico aplicado à estrutura. Foi encontrada uma dependência da fotocorrente com o campo elétrico bastante interessante, na forma de uma fotocondutância negativa controlada pelo campo elétrico aplicado à heteroestrutura. Atribuímos essa condutância negativa à interação entre estados localizados e estendidos no continuo se manifestando na forma de anticrossings e o aumento da fotocorrente para os valores de campo elétrico nos quais ocorrem esses crossings foi associado a transições de dois níveis do tipo Landau-Zener-Stückelberg-Majorama. No segundo trabalho, foi calculada a fotocorrente polarizada em spin de estruturas de poços quânticos de GaMnAs, na presença de um campo elétrico varável e um campo magnético de poucos teslas. O estudo mostrou a existência de domínios espectrais na região de THz do espectro eletromagnético, para os quais as estruturas propostas são altamente seletivas em spin. Para tais frequências, encontramos que a fotocorrente é polarizada em spin e a aplicação do campo elétrico é capaz de reverter forma muito eficiente o sinal da polarização. O comportamento observado sugere a possibilidade de mecanismos simples de controle sobre a fotocorrente e a Física por trás de tais efeitos foi entendida em termos dos acoplamentos dependentes de spin dos estados da estrutura, emergentes do perfil de potencial particular das heteroestruturas. Apresentamos dois trabalhos adicionais diretamente relacionados aos trabalhos principais. No primeiro trabalho, calculamos a corrente de escuro proveniente da estrutura de poços quânticos múltiplos com e sem barreiras de filtro, adicionando de forma integral a probabilidade de transmissão através da estrutura no modelo de Levine que determina essa corrente. Observamos que a presença das barreiras de filtro diminui significativamente a corrente de escuro dessa estrutura no regime de altos valores de campo elétrico. No segundo trabalho adicional, foi calculada a fotocorrente de uma estrutura de PQ com camada DMS, composta por ZnMnSe. Observamos a possibilidade de controle da polarização de spin com o campo elétrico, assim como no caso da estrutura composta de GaMnAs.
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Harb, Mahdi. "Microscopie de fonction d’onde électronique." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10150/document.
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Ce travail de thèse consiste à visualiser sur un détecteur sensible en position les oscillations spatiales des électrons lents (~ meV) émis par photoionisation au seuil en présence d’un champ électrique extérieur. La figure d’interférence obtenue représente quantiquement le module carré de la fonction d’onde électronique. Ce travail fondamental nous permet d’avoir accès à la dynamique électronique quelques µm autour de l’atome et donc de mettre en évidence plusieurs mécanismes quantiques (champ coulombien, interaction électron/électron..) se déroulant à l’échelle atomique. Malgré la présence d’un cœur électronique quoique limité dans Li, nous avons réussi, expérimentalement et pour la première fois, à visualiser la fonction d’onde associée aux états Stark quasi-discrets couplés au continuum d’ionisation. En outre, à l’aide des simulations quantiques de propagation du paquet d’ondes, basées sur la méthode de « Split-operator », nous avons réalisé une étude complète sur les atomes H, Li et Cs tout en dévoilant les effets significatifs des résonances Stark. Un très bon accord, sur et hors résonances, a été obtenu entre les résultats simulés et les résultats expérimentaux. Par ailleurs, nous avons développé un modèle analytique généralisable permettant de comprendre profondément le fonctionnement d’un spectromètre de VMI. Ce modèle repose sur l’approximation paraxiale, il est basé sur un calcul d’optique matricielle en faisant une analogie entre la trajectoire électronique et le rayon lumineux. Un excellent accord a été obtenu entre les prédictions du modèle et les résultats expérimentauxThis work of thesis aims to visualize, on a position sensitive detector, the spatial oscillations of slow electrons (~meV) emitted by a threshold photoionization in the presence of an external electric field. The interference figure obtained represents the square magnitude of electronic wavefunction. This fundamental work allows us to have access to the electronic dynamics and thus to highlight several quantum mechanisms that occur at the atomic scale (field Coulomb, electron/electron interaction..). Despite the presence an electronic core in Li atom, we have succeeded, experimentally and for the first time, to visualize the wave function associated with the quasi-discrete Stark states coupled to the ionization continuum. Besides, using simulations of wave packet propagation, based on the "Split-operator” method, we have conducted a comprehensive study of the H, Li and Cs atoms while revealing the significant effects of the Stark resonances. A very good agreement, on and off resonances, was obtained between simulated and experimental results. In addition, we have developed a generalized analytical model to understand deeply the function of VMI spectrometer. This model is based on the paraxial approximation; it is based on matrix optics calculation by making an analogy between the electronic trajectory and the light beam. An excellent agreement was obtained between the model predictions and the experimental results
Books on the topic "Operator split"
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Chŏn, Hong-t'aek. Nam-Pukhan kyŏngje t'onghap yŏn'gu: Pukhan kyŏngje ŭi hansijŏk pulli unyŏng pangan = A study of inter-Korean economic integration : temporary split operation of North Korean economy. Sŏul T'ŭkpyŏlsi: KDI, 2012.
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Schechter, Elizabeth. Self-Consciousness and "Split" Brains. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198809654.001.0001.
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The largest fiber tract in the human brain is the corpus callosum, which connects the two cerebral hemispheres. A number of surgeries severing this structure were performed on adults in the United States in the second half of the twentieth century. After they are surgically separated from each other in this way, a “split-brain” subject’s hemispheres begin to operate unusually independently of each other in the realms of perception, cognition, and the control of action—almost as if each had a mind of its own. But can a mere hemisphere really see? Speak? Feel? Know what it has done? The split-brain cases raise questions of psychological identity: How many subjects of experience are there within a split-brain subject? How many persons? How many minds? Under experimental conditions, split-brain subjects often act as though they were animated by two distinct conscious beings, evoking the duality intuition. On the other hand, a split-brain subject seems like one of us—not like two of us sharing one body. Split-brain subjects thus also evoke the unity intuition.This book is devoted to reconciling these two apparently opposing intuitions. The key to doing so are facts about the way self-consciousness operates in split-brain subjects. A split-brain subject is composed of two conscious psychological beings that fail to recognize each other’s existence and indeed cannot distinguish themselves from each other. Instead, each must first-personally identify with the split-brain subject as a whole, and in so doing, the two make themselves into one person.
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Schechter, Elizabeth. Dual Intentional Agency. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198809654.003.0003.
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This chapter defends the 2-agents claim, according to which the two hemispheres of a split-brain subject are associated with distinct intentional agents. The empirical basis of this claim is that, while both hemispheres are the source or site of intentions, the capacity to integrate them in practical reasoning no longer operates interhemispherically after split-brain surgery. As a result, the right hemisphere-associated agent, R, and the left hemisphere-associated agent, L, enjoy intentional autonomy from each other. Although the positive case for the 2-agents claim is grounded mainly in experimental findings, the claim is not contradicted by what we know of split-brain subjects’ ordinary behavior, that is, the way they act outside of experimental conditions.
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Schechter, Elizabeth. Objection from Sub-Cortical Structures. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198809654.003.0005.
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This chapter explains and responds to the major objection to the duality claims, the objection from sub-cortical structures. What gives rise to the duality intuition is that, after split-brain surgery, mental state interaction appears to operate oddly indirectly—when the mental states in question are in opposite hemispheres. Nonetheless, interhemispheric mental interaction is not entirely indirect, that is, not exclusively mediated by sensation/perception and re/action. According to the objection from sub-cortical structures, remaining direct interhemispheric interaction is substantial enough to support the 1-thinker claim over the 2-thinkers claim. I argue instead that remaining direct interhemispheric interaction is not so substantial, and that what remaining direct interhemispheric interaction there is remains consistent with the 2-thinkers claim that the rest of the data support. R and L are thus not discrete but still distinct thinkers.
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Trevor C, Hartley. Civil Jurisdiction and Judgments in Europe. Oxford University Press, 2017. http://dx.doi.org/10.1093/law/9780198729006.001.0001.
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This book offers comprehensive coverage and analysis of the relationship between the three instruments governing civil jurisdiction and judgments in Europe: the Brussels Regulation, the Lugano Convention, and the Hague Choice of Court Convention. The text provides a practical explanation of how the instruments operate, focusing on real-life litigation problems, and including extensive reference to the case-law of the Court of Justice of the European Union. The work is specifically designed for ease of navigation and is split into four parts. Part I offers an introduction to the features and scope of each of the instruments. Part II goes on to examine the issue of jurisdiction whilst Part III tackles recognition and enforcement. Finally, Part IV addresses procedural and systematic problems. A detailed table of contents and extensive cross-referencing throughout make it simple to home in on the relevant sections.
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Salton, Herman T. Dangerous Diplomacy. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780198733591.001.0001.
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This book assesses the role of the UN Secretariat in the Rwandan genocide. With the help of new sources, including the personal diaries and private papers of the late Sir Marrack Goulding, it situates the Rwanda operation within the context of bureaucratic friction existing at Headquarters in the early 1990s between the Department of Political Affairs (DPA) and the Department of Peacekeeping Operations (DPKO). The book argues that these units clashed not only over resources (a classic symptom of bureaucratic pathology) but also over the scope of peacekeeping and the role of the Secretary-General (SG) within it. This rivalry also reflected a split between a strong-willed SG determined to leave his mark on international affairs and to use his ‘political’ department independently of states, and Washington and the politico-military apparatus of the Pentagon, which in Somalia, Rwanda, Bosnia, and Haiti found itself increasingly at odds with Boutros-Ghali. Although the book looks at how this bureaucratic and power-political confrontation impacted on the Rwanda mission, it identifies the conceptual reasons for the DPA–DPKO split in the grey area that separates peacebuilding and peacekeeping. The difficulty of distinguishing these two key UN functions, coupled with the creative tension between SGs and states, explains why six decades after the birth of the UN, it has still not been possible to demarcate the exact roles of DPA and DPKO. Far from being dull and irrelevant, the book concludes that the UN bureaucracy is an intriguing barometer of the role of the Secretary-General in world politics.
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Perliger, Arie. Terrorism Networks. Edited by Jennifer Nicoll Victor, Alexander H. Montgomery, and Mark Lubell. Oxford University Press, 2016. http://dx.doi.org/10.1093/oxfordhb/9780190228217.013.28.
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A recent development in the field of terrorism studies is the growing understanding that analytical frameworks that focus on in-group social processes are highly effective in improving our understanding of the inner dynamics of terrorist groups. Many students of terrorism have begun to challenge some fundamental conventions regarding the way terrorist groups emerge and operate and the relations between members’ roles and profiles. Less attention has been given to the potential contribution of network science to understanding the relations between terrorist groups, as well as the factors shaping polities’ responses to terrorism. This chapter fills these gaps by explaining how network science can increase understanding of how terrorist groups compete, cooperate, and merge or split, as well as the dilemmas involved in responses to terrorism, which mostly involve coordination and cooperation on the international and national levels among various levels of government and agencies.
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Ellis-Evans, Aneurin. The Kingdom of Priam. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198831983.001.0001.
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This book is a regional history of Lesbos and the Troad from the seventh century BC to the first century AD which examines the extent to which this geographical region became politically, economically, and culturally integrated over this extended timeframe. The case studies in each chapter examine the various human and geographical factors which promoted regional integration, but also consider the political and identity-based considerations which limited integration and curtailed co-operation in particular areas. It is argued that this produced a situation in which an economically well-integrated region nevertheless remained politically fragmented and was only capable of unified action at moments of crisis. The book is split into two halves, with the first examining both the human and geographical factors which contributed to regional integration in the Troad and the politics of this process and the second examining the insular identity of Lesbos, the extent to which it was integrated into the mainland, and the consequences of this integration for the internal dynamic of the island. Cross-cutting these regional dynamics are the various imperial systems (Persian, Athenian, Macedonian, Attalid, Roman) which ruled this region and shaped its internal dynamics both through direct interventions in regional politics and through the pressures and incentives which these imperial systems created for local communities.
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Patberg, Markus. Constituent Power in the European Union. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198845218.001.0001.
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The European Union (EU) has been through almost two decades of near-constant constitutional crisis. The failure of the Constitutional Treaty was followed in quick succession by the struggles about the Lisbon Treaty, the Eurozone emergency, Brexit, and, recently, Corona-crisis-induced conflicts about financial solidarity. Over the course of these events, it has become clear that the EU’s constitutional development largely evades popular control. At the same time, the EU faces increasing politicization from below. While Eurosceptic forces seek to ‘take back control’ at the national level, pro-European citizens challenge the role of the states as the ‘masters of the treaties’. They reclaim what—in their view—has been illegitimately withheld from them: the right to shape the EU polity. This book advances the argument that these developments prompt the need for a theory of constituent power in the EU. The reason why European integration eludes citizen control and meets with growing discontent is that it allows constituted powers to operate as de facto constituent powers. Starting from claims to founding authority articulated in public narratives, the book explores competing models of constituent power in the EU—regional cosmopolitanism, demoi-cracy, split popular sovereignty, and destituent power—revealing their respective strengths and weaknesses. Rationally reconstructing established democratic practices of EU constitutional politics, it develops a new theory of constituent power in the EU. Addressing questions of the adequate conceptualization, allocation, agency, and institutionalization of constituent power, the book opens up the prospect of a more democratic mode of European integration.
Book chapters on the topic "Operator split"
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Martı́n, Antonio J. Calderón, and Diouf Mame Cheikh. "Strongly Split Poisson Algebras." In Non-Associative and Non-Commutative Algebra and Operator Theory, 165–74. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-32902-4_11.
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Ehrhardt, Torsten, and Karla Rost. "Restricted inversion of split-Bezoutians." In The Diversity and Beauty of Applied Operator Theory, 207–46. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-75996-8_12.
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Bosquetti, D., and J. Sánchez-Dehesa. "The Split-Operator Technique in Acoustical Physics." In IUTAM Symposium on Diffraction and Scattering in Fluid Mechanics and Elasticity, 107–14. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-017-0087-0_12.
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Blow, K. J. "System Analysis Using the Split Operator Method." In Optical Solitons, 127–40. Berlin, Heidelberg: Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/3-540-36141-3_6.
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König, C. "Operator Split for Three Dimensional Mass Transport Equation." In Computational Methods in Water Resources X, 309–16. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-010-9204-3_38.
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Heinig, Georg, and Karla Rost. "Split Algorithms for Centrosymmetric Toeplitz-plus-Hankel Matrices with Arbitrary Rank Profile." In The Extended Field of Operator Theory, 129–46. Basel: Birkhäuser Basel, 2006. http://dx.doi.org/10.1007/978-3-7643-7980-3_7.
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Hansen, Jan P., Thierry Matthey, and Tor Sørevik. "A Parallel Split Operator Method for the Time Dependent Schrödinger Equation." In Recent Advances in Parallel Virtual Machine and Message Passing Interface, 503–10. Berlin, Heidelberg: Springer Berlin Heidelberg, 2003. http://dx.doi.org/10.1007/978-3-540-39924-7_67.
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Gusev, Alexander, Vladimir Gerdt, Michail Kaschiev, Vitaly Rostovtsev, Valentin Samoylov, Tatyana Tupikova, Yoshio Uwano, and Sergue Vinitsky. "Symbolic-Numerical Algorithm for Solving the Time-Dependent Schrödinger Equation by Split-Operator Method." In Computer Algebra in Scientific Computing, 244–58. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/11555964_21.
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Golden, Leslie M. "Linear Operators." In Never Split Tens!, 23–26. Cham: Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-63486-9_4.
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Kołaczek, Damian, Bartłomiej J. Spisak, and Maciej Wołoszyn. "P $$\hbar $$ ase-Space Approach to Time Evolution of Quantum States in Confined Systems. The Spectral Split-Operator Method." In Advances in Intelligent Systems and Computing, 307–20. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-18058-4_24.
Full textConference papers on the topic "Operator split"
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Schwer, Douglas, and William Green, Jr. "Split-operator methods for computing steady-state reacting flow-fields." In 15th AIAA Computational Fluid Dynamics Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2001. http://dx.doi.org/10.2514/6.2001-2635.
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Xin-gang Ren, Zhi-xiang Huang, Xian-liang Wu, Si-long Lu, Yi-cai Mei, Hong-mei Du, and Lei Wu. "A split-operator method to simulate the left hand materials." In 2011 Cross Strait Quad-Regional Radio Science and Wireless Technology Conference (CSQRWC). IEEE, 2011. http://dx.doi.org/10.1109/csqrwc.2011.6036924.
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Su, Qichang C., S. Mandel, S. Menon, and R. Grobe. "Split operator solution of the time-dependent Maxwell's equations for random scatterers." In International Workshop on Photonics and Imaging in Biology and Medicine, edited by Qingming Luo, Britton Chance, and Valery V. Tuchin. SPIE, 2002. http://dx.doi.org/10.1117/12.462558.
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DeVries, Paul L. "Application of the Split Operator Fourier Transform method to the solution of the nonlinear Schrödinger equation." In AIP Conference Proceedings Volume 160. AIP, 1987. http://dx.doi.org/10.1063/1.36847.
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LoRe, Anthony, Paul Stoller, and Robert Hauser. "Maximizing Energy Revenues: Providing the Best Incentive to the Contract Operator." In 14th Annual North American Waste-to-Energy Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/nawtec14-3184.
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Communities that own waste-to-energy (WTE) facilities rely heavily on the revenues generated by their facility to help pay for the costs to finance, operate and maintain these facilities. The two primary revenue streams are tipping fees and energy sales, generally in the form of electricity. While communities often retain all of the tipping fee revenue, revenue from the sale of energy is nearly always shared with the contract operator. In some cases the shared energy revenues include both capacity and electricity payments. The basis of this strategy is to offer the contract operator an added incentive to maximize this revenue stream through more efficient operation and, in the case of capacity payments, to meet certain capacity commitment criteria required by the energy purchaser. This strategy recognizes that the contract operator has some degree of control over the factors that affect energy production. Under most existing service agreements, which date back to the 1980s, energy revenues are shared on a 90/10 basis, with 90 percent going to the community. Now that many of these service agreements are coming up for renewal or are expiring, communities will need to revisit how best to share energy revenues with the contract operator in order to maximize the total revenues retained by the community. This paper analyzes several different approaches to sharing energy revenues in light of the operational experience gained over the past 20 plus years and concludes that, while energy revenue sharing is still in the best interest of the community, the widely employed strategy of a 90/10 split may not offer the best incentive, and therefore may not lead to the maximization of energy revenues to the community.
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Reiss, Robert, Bo Qian, and Win Aung. "Eigenvalues for Moderately Damped Linear Systems Determined by Eigensensitivity Analysis." In ASME 1990 Design Technical Conferences. American Society of Mechanical Engineers, 1990. http://dx.doi.org/10.1115/detc1990-0079.
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Abstract A new method is presented to determine approximate closed-form solutions for the complex-valued frequencies of moderately damped linearly elastic structures. The approach is equally applicable to finite degree of freedom systems and distributed parameter systems. The damping operator is split into two components, the first of which uncouples the quadratic eigenvalue equation, and the eigenvalues are expressed as a power series in the second component of the damping operator. Specific numerical examples include both finite degree of freedom and distributed parameter systems. It is shown that for moderate damping, that is, when the second component of the damping operator is small, but not negligible, the series solution truncated after quadratic terms provides an excellent approximation to the true eigenvalues.
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Silva, Ygor, João Almeida, Gabriel Macedo, and Anibal Bezerra. "Estudo das propriedades óticas de células solares de banda intermediária utilizando o método Split Operator." In MOL2NET 2018, International Conference on Multidisciplinary Sciences, 4th edition. Basel, Switzerland: MDPI, 2018. http://dx.doi.org/10.3390/mol2net-04-05774.
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Barnett, Julian, Richard Wilkinson, Alan Kirkham, and Keith Armstrong. "Under Pressure Operations on Dense Phase CO2 Pipelines: Issues for the Operator." In 2014 10th International Pipeline Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/ipc2014-33309.
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National Grid, in the United Kingdom (UK), has extensive experience in the management and execution of under pressure operations on its natural gas pipelines. These under pressure operations include welding, ‘hot tap’ and ‘stopple’ operations, and the installation of sleeve repairs. National Grid Carbon is pursuing plans to develop a pipeline network in the Humber and North Yorkshire areas of the UK to transport dense phase Carbon Dioxide (CO2) from major industrial emitters in the area to saline aquifers off the Yorkshire coast. One of the issues that needed to be resolved is the requirement to modify and/or repair dense phase CO2 pipeline system. Existing under pressure experience and procedures for natural gas systems have been proven to be applicable for gaseous phase CO2 pipelines; however, dense phase CO2 pipeline systems require further consideration due to their higher pressures and different phase behaviour. Consequently, there is a need to develop procedures and define requirements for dense phase CO2 pipelines. This development required an experimental programme of under pressure welding trials using a flow loop to simulate real dense phase CO2 pipeline operating conditions. This paper describes the experiments which involved: • Heat decay trials which demonstrated that the practical limitation for under pressure welding on dense phase CO2 systems will be maintaining a sufficient level of heat to achieve the cooling time from 250 °C to 150 °C (T250–150) above the generally accepted 40 second limit. • A successful welding qualification trial with a welded full encirclement split sleeve arrangement. The work found that for the same pipe wall thickness, flow velocity and pressure, dense phase CO2 has the fastest cooling time when compared with gaseous phase CO2 and natural gas. The major practical conclusion of the study is that for dense phase CO2 pipelines with a wall thickness of 19.0 mm or above, safe and practical under pressure welding is possible in accordance with the existing National Grid specification (i.e. T/SP/P/9) up to a flow velocity of around 0.9 m/s. The paper also outlines the work conducted into the use of the Manual Phased Array (MPA) inspection technique on under pressure welding applications. Finally, the paper identifies and considers the additional development work needed to ensure that a comprehensive suite of under pressure operations and procedures are available for the pipeline operator.
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Lorini, Emiliano, and Francois Schwarzentruber. "Multi-Agent Belief Base Revision." In Thirtieth International Joint Conference on Artificial Intelligence {IJCAI-21}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/ijcai.2021/270.
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We present a generalization of belief base revision to the multi-agent case. In our approach agents have belief bases containing both propositional beliefs and higher-order beliefs about their own beliefs and other agents’ beliefs. Moreover, their belief bases are split in two parts: the mutable part, whose elements may change under belief revision, and the core part, whose elements do not change. We study a belief revision operator inspired by the notion of screened revision. We provide complexity results of model checking for our approach as well as an optimal model checking algorithm. Moreover, we study complexity of epistemic planning formulated in the context of our framework.
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Sou, Akira, Kosuke Hayashi, and Tsuyoshi Nakajima. "Evaluation of Volume Tracking Algorithms for Gas-Liquid Two-Phase Flows." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45164.
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Qualitative and quantitative evaluations of volume tracking algorithms such as DA, FLAIR, MARS, CIP and VTEMC were conducted. Wide variety of two-dimensional test problems including (1) a circle transported in simple translation and rotational field, (2) a bubble rising in 45° slanted gravity field, (3) zigzag motion of a bubble in a vertical channel, and (4) a bubble rising in a stagnant liquid in axissymmetric cylindrical coordinate were chosen in the present study. As a result of these tests, the superiority of the cell-centered piecewise linear algorithm with the divergence treatment in operator split and especially with embedded micro cells was confirmed. Applicability of these algorithms to three-dimensional problems has to be examined in the future works.
Reports on the topic "Operator split"
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Chen, X., J. M. Connors, and C. H. Tong. A flexible method to calculate the distributions of discretization errors in operator-split codes with stochastic noise in problem data. Office of Scientific and Technical Information (OSTI), January 2014. http://dx.doi.org/10.2172/1119920.
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Ostashev, Vladimir, Michael Muhlestein, and 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.
Full textAbstract:
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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Dell G. F. and S. Lee. Split tune operation of a hybrid booster lattice ?x = 3.820, ?y = 4.830. Office of Scientific and Technical Information (OSTI), June 1986. http://dx.doi.org/10.2172/1150421.
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Williams, Michael, Marcial Lamera, Aleksander Bauranov, Carole Voulgaris, and Anurag Pande. Safety Considerations for All Road Users on Edge Lane Roads. Mineta Transportation Institute, March 2021. http://dx.doi.org/10.31979/mti.2021.1925.
Full textAbstract:
Edge lane roads (ELRs), also known as advisory bike lanes or advisory shoulders, are a type of shared street where two-way motor vehicle (MV) traffic shares a single center lane, and edge lanes on either side are preferentially reserved for vulnerable road users (VRUs). This work comprises a literature review, an investigation of ELRs’ operational characteristics and potential road user interactions via simulation, and a study of crash data from existing American and Australian ELRs. The simulation evaluated the impact of various factors (e.g., speed, volume, directional split, etc.) on ELR operation. Results lay the foundation for a siting criterion. Current American siting guidance relies only upon daily traffic volume and speed—an approach that inaccurately models an ELR’s safety. To evaluate the safety of existing ELRs, crash data were collected from ELR installations in the US and Australia. For US installations, Empirical Bayes (EB) analysis resulted in an aggregate CMF of .56 for 11 installations observed over 8 years while serving more than 60 million vehicle trips. The data from the Australian State of Queensland involved rural one-lane, low-volume, higher-speed roads, functionally equivalent to ELRs. As motor vehicle volume grows, these roads are widened to two-lane facilities. While the authors observed low mean crash rates on the one-lane roads, analysis of recently converted (from one-lane to two-lane) facilities showed that several experienced fewer crashes than expected after conversion to two-lane roads.