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.
Results
Showing 1 to 20 of 24 for “"Iterative Solver"”.
-
Multi-scale problems: an improved non-intrusive algorithm that enhances FEA platforms with the generalized finite element method; An improved preconditioned conjugate gradient solver for hierarchical generalized finite element systems of equations
… SGFEM gl systems of equations makes feasible iterative schemes that solve SGFEM gl linear system of equations. The reduced memory requirements of iterative solvers over direct solvers, combined with improved speed, make larger-scale simulations possible. An iterative solver called the …
-
Domain decomposition and high order discretization of elliptic partial differential equations
… and their solutions using either direct or iterative methods are topics of continuing research. The recent advent of parallel computer architectures has resulted in a search for good parallel algorithms to solve such systems, which in turn has led to a recent burgeoning of research into …
-
Optimally Navigating a Piecewise-deterministic World
… it navigates a domain. We present an efficient iterative solver to recover the mode-dependent value functions and optimal policies for this problem. The second proposes a model of optimal foraging in a continuous domain while subject to predation. We present numerical experiments to demonstrate …
-
Auto-tuning on the macro scale : high level algorithmic auto-tuning for scientific applications
… algorithmic choices (such as whether to use an iterative solver or a direct solver). We present and analyze four novel auto-tuning systems that incorporate several techniques that fall along a spectrum from the low-level to the high-level: i) a multiplatform, auto-tuning parallel code generation …
-
Use of Machine Learning for Automated Convergence of Numerical Iterative Schemes
… occurs when a sequence of increasingly refined iterative solutions approaches a value consistent with the modeled phenomenon. Approximations using iterative schemes need to satisfy convergence criteria, such as reaching a specific error tolerance or number of iterations. The schemes often bypass …
-
Parallel computation in efficient non-linear finite element analysis with applications to soft-ground tunneling project
… existing finite element software with direct or iterative solver methods.
-
Integral Equation Methodologies for the Signal Integrity Analysis of PCB and Interconnect Structures in Layered Media From DC to Multi-Ghz Frequencies
… introduced is a three-dimensional dynamic field solver for the analysis of interconnect structures with electrodynamic properties that cannot be quantified accurately using transmission line theory. To date, the development of electrodynamic integral equation solvers that can handle realistic …
-
Finite element analysis of 3D electric machine problems
… solve the singular system directly by using an iterative solver. Another is to regularize the singular matrix with tree-cotree splitting. An algorithm of finding the minimum spanning tree is given. The two solutions have different effects on the convergence of iterative solvers, which is …
-
The Buffered Block Forward Backward technique for solving electromagnetic wave scattering problems
… cannot be solved by direct inversion and iterative methods are employed instead. Various iterative techniques for solving the matrix equation are presented including stationary methods such as the ”forwardbackward” technique, as well its matrix-block version. A novel iterative solver …
-
Solution of large scale elastic problems with the boundary element method : applications to infrasound and micro-seismicity generated by wind turbines
… box fast and memory efficient boundary element solver for general multi-domain static as well as harmonic problems based on the hierarchical matrix methodology combined with the algebraic low rank approximation technique, known as Adaptive Cross Approximation (ACA), is proposed. For the …
-
Shape and Topology Optimization for electro-mechanical energy converters
… to treat the vector case. Secondly, an iterative solver is designed so as to solve efficiently the large-scale linear systems arising from the design problem. Third, the design improvement capabilities are extended by developing an integrated and unified formalism for simultaneous shape …
-
Joint Equalization and Decoding via Convex Optimization
… and some hard-disk drives have started using iterative decoding. Despite progress in the area of reduced-complexity detection and decoding algorithms, there has been some resistance to the deployment of turbo-equalization (TE) structures (with iterative detectors/decoders) in …
-
Study of High Harmonic Fast Waves Interactions in the Scrape off Layer of NSTX-U
… profile is obtained using a non-linear iterative solver with proper mesh refinement conditions. Furthermore, this work focuses on investigating the effect of the SOL plasma density profile on the fast-wave propagation at different antenna phasing. The simulation results show that the …
-
A Study of Techniques to Solve the Disparate Mesh Size Problem With an Application to Sinuous Antennas
… matrix. Since the FMM algorithm relies on iterative solvers to solve the matrix equation, the fast in FMM becomes a misnomer if the iterative solver converges very slowly or not at all. The sinuous antenna embodies the disparate mesh size problem, so if any of the recent fast algorithms in …
-
A Mesh Objective Algorithm for Modeling Mode-I Cracks Using a Standard Finite Element Formulation
… the stress components without the need for an iterative solver for both linear and nonlinear softening. Next, a computationally efficient crack tracking algorithm is implemented to preclude the misalignment of the stress field. The tracking algorithm uses the crack orientation predicted from …
-
Statistical Preconditioning and Quantitative Imaging for Electrical Impedance Tomography
… squares problems, and if the problems are large, iterative solvers are typically the method of choice, with the Krylov subspace methods a frequently used family of iterative schemes. In the case of nonlinear least squares problems, local linearization is an additional step that must be completed …
-
Nodal Reordering Strategies to Improve Preconditioning for Finite Element Systems
… of partial differential equation models) iterative methods and, in particular, efficient preconditioners need to be developed. In this study, we consider application of incomplete LU (ILU) preconditioners for finite element models to partial differential equations. Since finite elements …
-
NEW COMPUTATIONAL METHODS FOR OPTIMAL CONTROL OF PARTIAL DIFFERENTIAL EQUATIONS
… a new strategy that leads to a robust multigrid solver is employed to define the coarse grid operator. Numerical simulations are provided to illustrate the efficiency of the proposed method, which shows to be computationally more efficient than the popular full approximation storage (FAS) …
-
Phenomena in the Solar Corona: characteristic structure and dynamic evolution
… was fully understood, it was used to test a DEM solver and quantify the ‘goodness-of-fit’ that could be achieved. This allowed the imitations of the DEM method to be understood. As the model parameter space was altered, a number of changes in the resulting synthetic DEMs were observed. In most …
-
Recycling Krylov Subspaces and Preconditioners
… to analyze further. We use recycling BiCG in the Iterative Rational Krylov Algorithm (IRKA) for interpolatory model reduction and in the VMC algorithm. For a model reduction problem, we show up to 70% savings in iterations, and we also demonstrate that solving the problem without recycling leads …
Page 1 of 2