Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 115 for “"Integrators"”.
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Geometric Integrators for Hamiltonian PDEs
… symplectic form, and derive novel symplectic integrators of arbitrary order exploiting the particular structure of AL where the standard techniques fail.</p> <p>To facilitate the construction of scalable, parallelizeable implementations, we have developed an extension class library for PETSc …
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Exponential integrators: tensor structured problems and applications
… such systems involves using exponential integrators. In general, these kinds of schemes do not require the solution of (non)linear systems but rather the action of the matrix exponential and of some specific exponential-like functions (known in the literature as φ-functions). In this PhD …
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Multi-Symplectic Integrators for Nonlinear Wave Equations
<p>Symplectic (area-preserving) integrators for Hamiltonian ordinary differential equations have shown to be robust, efficient and accurate in long-term calculations. In this thesis, we show how symplectic integrators have a natural generalization to Hamiltonian PDEs by introducing the concept of …
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Exponential Integrators for the Incompressible Navier-Stokes Equations
… grow linearly with problem size. Exponential integrators, used typically to solve systems of ODEs, utilize matrix vector products of the exponential of the Jacobian on a vector. For large systems, this product can be approximated efficiently by Krylov subspace methods. However, in contrast to …
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Development and application of time-temperature integrators to thermal food processing
… and development into a range of time-temperature integrators (TTIs) for the measurement of process values for food heat treatments. The TTIs are based on the first order thermal degradation of bacterial \(\alpha\)-amylases. Two new TTIs are described, one for mild pasteurisation treatments of a …
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How to develop and deploy system integrators within component-focused engineering organizations
… company can effectively introduce system integrators in their organization. To this end, the question of how to analytically identify the necessary skills and characteristics of an ideal system integrator will be addressed. In this thesis, it is assumed that a company is currently …
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Developing a boundary object model to analyze communication interfaces : applications for system integrators
Physical information is transferred between technical systems through wires, beams, and other physical attributes, while more intangible information is typically transferred between communities of people through artifacts such as documents, e-mails, etc. This research attempts to characterize these …
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Study of Vortex Ring Dynamics in the Nonlinear Schrödinger Equation Utilizing GPU-Accelerated High-Order Compact Numerical Integrators
<p>We numerically study the dynamics and interactions of vortex rings in the nonlinear Schrödinger equation (NLSE). Single ring dynamics for both bright and dark vortex rings are explored including their traverse velocity, stability, and perturbations resulting in quadrupole oscillations. …
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No ‘off’ switch (but not being all things to all people at all times): Extreme integrators’ use of avatar-mediated connectivity
… of connectivity by exploring how ‘extreme integrators’—those who exhibit minimal distinction and high overlap between ‘work’ and ‘play’ aspects of their life—regulate, moderate and otherwise manage their regular and relatively high volume of communication media messages. Of particular …
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Solving the N-body problem in astrophysics
… part of this Thesis, I develop new symplectic integrators which provide a solution for the N-body problem. The integrators decompose the N-body problem into a superposition of two-body problems, which are integrable. Since they are symplectic, the integrators conserve all Poincaré invariants …
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Study and analysis of best practices for the development of systems engineers at a multi-national organization
… * Define the role and need of systems engineers/integrators within a large organization. * Analyze the system engineering procedures and availability of systems engineers/integrators to fill the need within multiple business units of a large multinational corporation and recommend best practices …
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Canonical integration methods for Hamiltonian dynamical systems
… structure) that call for special numerical integrators, namely canonical methods. Recent research in this aspect have shown that canonical numerical integrators may be needed for Hamiltonian systems. In this thesis, we explore possibilities for the construction of integrators that preserve …
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Multi-rate time integration on overset meshes
… in resolution, standard explicit time integrators limit the maximum allowable timestep across the entire simulation domain to that of the finest mesh, per the well-known Courant-Friedrichs-Lewy (CFL) condition. What therefore results is a potentially high amount of computational work …
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Polynomial-Based Methods for Time-Integration
… and approximation theory to construct new integrators. This strategy allows us to trivially satisfy order conditions and easily construct a range of implicit or explicit integrators with properties such as parallelism and high-order of accuracy. The breadth of our framework is made possible …
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Longer Time Steps for Molecular Dynamics
… also holds for multiple time stepping (MTS) integrators which evaluate different parts of the force at different frequencies. This work is an attempt to construct MTS integrators which are stable for long time steps. This has been done by applying a seminal idea that appeared in [GASSS98]: …
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Development and Acceleration of Parallel Chemical Transport Models
… in addition to modifications to KPP allowing KPP integrators to interface with GEOS-Chem. A variety of different numerical integrators are tested on GEOS-Chem, demonstrating that KPP provided chemical integrators produce more accurate solutions in a given amount of time than the original GEOS-Chem …
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Explicit, Multi-Map Symplectic Integrator for Three -Body Classical Trajectory Studies in Hyperspherical Coordinates
Symplectic integrators are well known for preserving the phase space volume in Hamiltonian dynamics and are particularly suited for problems that require long integration times. There is a general operator splitting method for developing explicit symplectic integration algorithms to any arbitrary …
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Explicit, multi-map symplectic integrator for three-body classical trajectory studies in hyperspherical coordinates
Symplectic integrators are well known for preserving the phase space volume in Hamiltonian dynamics and are particularly suited for problems that require long integration times. There is a general operator splitting method for developing explicit symplectic integration algorithms to any arbitrary …
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Industrial Upgrading and China’s Electric Vehicle and Wind Turbine Industries
… a variant cascade effect that Chinese sub-system integrators tend to provide more standardised products and the relationship between the system integrators and the sub-system integrators is not as deep as the case in the Europe. The Chinese government’s industrial policies to support the upgrade …
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