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 63 for “"Initial guess"”.
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Optimal redesign in the presence of system constraint perturbations
… with perturbed constraints include using the initial guess from the unperturbed problem as the initial guess for the perturbed problem, and using the final solution to the unperturbed problem as the initial guess for the perturbed problem. The estimated solutions can also be used as an initial …
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Galerkin Projections Between Finite Element Spaces
… problem with Newton's method requires an initial guess of the solution on a refined space, which can be found by interpolating the solution from a previous refinement. Improving the accuracy of the representation of the converged solution computed on a coarse mesh for use as an initial …
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Collocation With Nonlinear Programming for Two-Sided Flight Path Optimization
… robust, ambitious problems require a reasonable initial guess of the discretized solution from which the optimizer may converge. A method for generating a good initial guess, requiring no a priori information about the solution, is developed using genetic algorithms. The semi-DCNLP, in …
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System identification techniques and modeling for nonintrusive load diagnostics
… parameter identification programs is that a good initial guess is needed for the iterative optimization routines typically used to find parameter estimates. Two approaches are given to overcome this problem for certain systems. The first extends conventional optimization methods to identify model …
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Lift on a sphere in shear flow near flat channel bed
… Since the iteration method requires a good initial guess, the linear solution of the partial differential equations is used for the initial guess, where the linear solution is the obtained by solving the differential equations without non-linear terms. The computer model developed can …
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Fast Polarizable Force Field Computation in Biomolecular Simulations
… from previous timesteps to calculate an accurate initial guess for iterative methods leads to an energy drift and compromises the volume-preserving property of the integration. Iterative methods with zero initial guess do not lead to perceptible energy drift if a reasonably strict convergence …
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Two-stage path planning approach for designing multiple spacecraft reconfiguration maneuvers and application to SPHERES onboard ISS
… solution approach quickly provides a feasible initial solution by solving a simplified version without differential constraints using a bi-directional Rapidly-exploring Random Tree (RRT) planner. A transition algorithm then augments this guess with feasible dynamics that are propagated from the …
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Optimal strategies for selecting from multiple asteroid interception targets
… found by the PSO algorithm is then used to initialize a much more accurate solution method using NLP. The two optimization techniques are applied in series because of the problem complexity. The PSO algorithm is a stochastic process and can therefore not guarantee optimality and struggles to …
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Non-Destructive Testing of metallic structures based on electromagnetic computational methods
… frequencies. The solver exploited an optimised initial guess to accelerate the EM eddy current computation for probes scanning (over a metallic plate) process. The bi-conjugate gradients stabilised (BICGS) method was utilised in solving the equation of finite-element sparse matrices - matrices …
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The nonlinear differential semblance algorithm for plane waves in layered media
… approximate a global minimizer from a crude initial guess for typical band-limited data.
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An Sn Application of Homotopy Continuation in Neutral Particle Transport
… continuation as a means of providing a better initial guess for difficult problems. We investigate various homotopy formulations for two primary diffcult problems: a thick-diffusive fixed internal source, and a k-eigenvalue problem with high dominance ratio. We also investigate the usefulness …
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ΝΕΕΣ ΜΕΘΟΔΟΙ ΕΠΙΛΥΣΗΣ ΣΥΣΤΗΜΑΤΩΝ ΜΗ ΓΡΑΜΜΙΚΩΝ ΑΛΓΕΒΡΙΚΩΝ Η/ΚΑΙ ΥΠΕΡΒΑΤΙΚΩΝ ΕΞΙΣΩΣΕΩΝ
… SIMPLE COMPUTATION. IT DOES NOT REQUIRE A GOOD INITIAL GUESS OF THE SOLUTION AND IT DOES NOT DIRECTLY NEED FUNCTION EVALUATIONS. A PROOF OF CONVERGENCE IS ALSO GIVEN. NEXT, THE ABOVE METHOD IN GENERALIZED AND A NEW ONE IS DEVELOPED FOR THE NUMERICAL SOLUTION OF SYSTEMS OF NONLINEAR EQUATIONS IN …
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Simulating energy transfer between nanocrystals and organic semiconductors
… learning models on DFT data, a much improved initial guess can be made, greatly accelerating DFT optimizations. Generating and examining this data set also revealed a remarkable degree of structure, that perhaps can be further exploited in the future.
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Improvements in digital image correlation and application in material mechanical test
… matching based method is proposed to provide an initial guess for all points of interest with semi-subpixel level accuracy in cases with small or large translation, deformation, or rotation. The bisection searching strategy is presented to automatically adjust the frame step for varying practical …
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A new computationally facile approximation of electrostatic potential suitable for macromolecules
… of the analytical approximation as an initial guess for traditional numerical methods as a means of improving the convergence of iterative solutions is investigated and found to be quite promising.
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Activity-Scaling SAR with Direct Hybrid Encoding for Signed Expressions for AIoT Applications
… two thresholds. The activity-scaling mode has an initial guess and takes two steps per cycle to approach the sampled input until overshoot. After that, it performs a ternary search to the LSB. The direct hybrid encoding for signed expressions mode places one of the thresholds at the normal binary …
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Numerical solution methods for differential game problems
… a limited convergence space that requires a good initial guess for both the state and less intuitive costate. The decomposition method in which optimal trajectories for each player are iteratively calculated is a direct method that bypasses the need for costate information. Because a linearized …
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Hydrologic data assimilation of multi-resolution microwave radiometer and radar measurements using ensemble smoothing
… already performed in the EnKF which provides the initial guess. It is used to assimilate observed L-band radiobrightness temperatures during the Southern Great Plains Experiment 1997. Estimated surface and root zone soil moisture is evaluated using gravimetric measurements and flux tower …
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Modeling, Discontinuous Galerkin Approximation and Simulation of the 1-D Compressible Navier Stokes Equations
… equations. The first method requires making an initial guess and employs a Newton based solver. The second method is based on a pseudo-transient continuation method. In this method one initializes the dynamic model and integrates forward for a fixed time period to obtain a profile that …
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Rigid Body Constrained Motion Optimization and Control on Lie Groups and Their Tangent Bundles
… equation of mechanics is utilized for generating initial guess trajectories which satisfy path and terminal time constraints. The results contained herein show, for the first time, that direct transcription of trajectory optimization and optimal control problems on Riemannian manifolds may be …
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