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 97 for “"ROMS"”.
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Stabilization of POD-ROMs
… describes several approaches for stabilizing POD-ROMs (that is, reduced order models based on basis functions derived from the proper orthogonal decomposition) for both the CDR (convection-diffusion-reaction) equation and the NSEs (Navier-Stokes equations). Stabilization is necessary because …
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Modelling Benguela niños using the regional oceanic modeling system (ROMS)
… could the Regional Oceanic Modelling System (ROMS) reproduce the seasonal cycle of the equatorial Atlantic? Secondly, what is the nature of the link between remote forcing in the western equatorial Atlantic and Benguela Niños/Niñas? Thirdly, what is the impact of these events on the equatorial …
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3-D Modeling of Nearshore Circulation Using ROMS-SWAN: Model Upgrades and Evaluation
<p>Regional Ocean Modeling System (ROMS v 3.0), a three dimensional numerical model, was recently modified for shallow water applications by including wave induced radiation stresses provided through coupling with a wave propagation model (e.g., SWAN, REF/DIF). The coupled model has been applied to …
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Intelligent Planning and Assimilation of AUV-Obtained Measurements Within a ROMS-Based Ocean Modeling System
… systems (bouys, profilers, etc.) cannot. A ROMS-based data assimilation method was developed that intelligently plans for and integrates AUV measurements with the goal of minimizing model standard deviation. An algorithm developed for this system is first described that optimizes paths for …
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Building A Mean-state Of Oceanographic Properties (Temperature And Salinity) For The Kwazulu-natal Bight Using The Roms Model: A Contribution Towards Marine Protected Areas Analysis
… study uses a 30-year, high-resolution, regional ROMS simulation to build a climatology representative of the mean-state of the Bight. The model is also used to investigate the seasonal and annual variability as well as the influence of the Agulhas Current on the shelf. The Bight was cooler and …
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Reduced-Order Atmospheric Density Modeling for LEO Satellite Orbital Reentry Prediction
… Reduced-order atmospheric density Models (ROMs) have shown potential to provide good predictive performance at a significantly lower computational cost, by propagating a low-dimensional representation of the atmospheric density state instead of the entire density state. In this thesis, ROMs …
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Data-Driven Variational Multiscale Reduced Order Modeling of Turbulent Flows
… is significantly more accurate than standard ROMs. Furthermore, we propose a new hybrid ROM framework for the numerical simulation of fluid flows. This hybrid framework incorporates two closure modeling strategies: (i) A structural closure modeling component that involves the recently proposed …
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Optimal reservoir management using adaptive reduced-order models
… dimensional space. Example cases demonstrate ROMs ability to reduce the computational costs by 0(100) while providing close overall agreement to FOM for instances with significant difference in boundary conditions (well placements and controls). ROMs are potentially perfect alternatives to …
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A Search for Low-Amplitude Variability Among Population I Main Sequence Stars
… thousands of stars, the Robust Median Statistic (RoMS) is proven more effective for finding low-amplitude variables than the traditional error curve approach. A reputable computer program called DAOPHOT was used to perform PSF fitting, whereas programs, CLUSTER and RoMS, were created to carry out …
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Filter Based Stabilization Methods for Reduced Order Models of Convection-Dominated Systems
… to design new regularized reduced order models (ROMs) for under-resolved simulations of unsteady, nonlinear, convection-dominated systems. The new ROMs proposed are variable delta filtering applied to the evolve-filter-relax ROM (V-EFR ROM), variable delta filtering applied to the Leray ROM, and …
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Optimization methods for parameter identifications in settings with only partial knowledge
… a framework for training Reduced-Order Models (ROMs) with Physics-Informed Neural Ordinary Differential Equations (PINODE). In particular, a classic technique of collocation points is adapted to transfer knowledge from a known equation to a model that approximates solutions of that equation. The …
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Model order reduction in the frequency domain via spectral proper orthogonal decomposition
… space and time. However, reduced-order models (ROMs) using SPOD modes have not yet been developed. Hence, in this study we investigate the potential of a novel approach utilizing SPOD modes to construct the lower-dimensional subspace for ROMs. Upon the discrete-time Fourier-transform (DFT) of …
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Reduced order modeling of convection-dominated flows, dimensionality reduction and stabilization
… stability and accuracy of the projection based ROMs on the learned manifold a posteriori. We extend the eigenvalue reassignment method of stabilization of linear time-invariant ROMs, to the more general case of linear time-varying systems. Through a post-processing step, the ROMs are controlled …
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Numerical Analysis for Data-Driven Reduced Order Model Closures
… and numerical aspects of reduced order models (ROMs). In an under-resolved regime, the classical Galerkin reduced order model (G-ROM) fails to yield accurate approximations. Thus, we propose a new ROM, the data-driven variational multiscale ROM (DD-VMS-ROM) built by adding a closure term to the …
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Model Reduction of Nonlinear Fire Dynamics Models
… improving wildland fire reduced-order models (ROMs), creating new ROM techniques for nonlinear systems, and preserving optimality when discretizing a continuous-time ROM. Currently, proper orthogonal decomposition (POD) is being used to reduce wildland fire-spread models with limited success. …
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A numerical investigation of the influence of monsoonal wind reversals over the East African coastal ocean
… using the Regional Ocean Modelling System (ROMS) ROMS is forced with the Comprehensive Ocean Atmosphere Data Sets (COADS) while the initial and lateral boundary conditions are derived from the World Ocean Atlas The domain area of the model study is constrained by 10•S to 15'N and 3S"E to …
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Environmental influences on banana shrimps of the Sofala Bank, Mozambique Channel
… nested, coastal, Regional Ocean Modeling System (ROMS) of the Sofala Bank is developed. In general, the model agrees well with available observations and literature. The ROMS outputs and self-organizing map analysis indicate that the shelf circulation, structure and river plumes are strongly …
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The biomechanical analysis of the hand in rheumatoid arthritis patients with MCP arthroplasty
… Data were processed to give maximum, minimum and ROMs of flexion/extension and abduction/adduction at all MCPs during four movements: pinch grip, key grip, fist clench and hand spread. Results showed ROM was decreased by ageing, further by RA, and further again by replacement surgery. MCP surgery …
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Frequency-Domain Learning of Dynamical Systems From Time-Domain Data
… measurements to construct reduced order models (ROMs), a small scale model that well approximates the true system, directly from input/output data. Frequency domain data-driven methods, which require access to values (and in some cases to derivatives) of the transfer function, have been very …
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Functional level modeling of digital devices
… various devices which include counters, RAMs, ROMs, microprocessor peripheral chips and CPUs. Processors modeled include the Intel 8080, the Zilog Z80 (single chip CPUs) and the Bendix BDX930 (MSI).
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