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 39 for “"Dynamic Mode Decomposition"”.
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Wavelet-based Dynamic Mode Decomposition in the Context of Extended Dynamic Mode Decomposition and Koopman Theory
Koopman theory is widely used for data-driven modeling of nonlinear dynamical systems. One of the well-known algorithms that stem from this approach is the Extended Dynamic Mode Decomposition (EDMD), a data-driven algorithm for uncontrolled systems. In this thesis, we will start by discussing the …
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Dynamic mode decomposition with application to optimal control
High-dimensional fluid dynamics systems are central to a variety of modern engineering challenges. Direct numerical simulation of these processes is possible, but the high computational cost of these simulations is always an important consideration. Optimal control of these high-dimensional fluid …
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Optimization Methods for Dynamic Mode Decomposition of Nonlinear Partial Differential Equations
Reduced-order models have long been used to understand the behavior of nonlinear partial differential equations. Naturally, reduced-order modeling techniques come at the price of either computational accuracy or computation time. Optimization techniques are studied to improve either or both of …
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Animal Motion Analysis and Approximation for Robotics
… video, not many researches as of yet are using dynamical system analysis techniques such as dynamic mode decomposition, extended dynamic mode decomposition, or even Koopman method to understand and compare the motion across different species. Thus, the goal of this thesis is to further develop …
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Data-Driven Modeling of Tracked Order Vibration in Turbofan Engine
… no representative and efficient physics-based models with the adequate fidelity to perform vibration predictions in aircraft engines, given various parametric dependencies existing among different attributes such as temperature, pressure, and external conditions. This gap in research is …
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Phase Space Structure of Disequilibrium in the Milky Way
… structures, using a combination of analytic modeling, simulations, and Dynamic Mode Decomposition to study explicitly their formation and evolution in the presence of self gravity. In doing so, we have demonstrated the first application of DMD to collisionless, self-gravitating systems. We …
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Large eddy simulations of premixed turbulent flame dynamics : combustion modeling, validation and analysis
… conditions are some of the key requirements of modem-day combustors. To achieve these objectives, lean premixed flames are generally preferred as they achieve efficient and clean combustion. A drawback of lean premixed combustion, however, is that the flames are more prone to dynamics. The …
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Description of Coherent Structures in the Atmospheric Boundary Layer By Model Reduction of the Surface Pressure
… of these features suggests description by model reduction. To this end, an array of pressure transducers was deployed on the ground at Reese Technology Center in Lubbock, Texas, and the pressure fluctuations were recorded over nearly two diurnal cycles. A program for computation of the …
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A dynamical systems approach to the study of local phenomena in fluid flows
… in the utilization of nonlinear tools from dynamical systems theory. In fluid dynamics, prominent examples are Koopman eigenfunctions (through dynamic mode decomposition) and spectral submanifolds. Due to their immense popularity, both of these techniques have been studied extensively, to …
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Application of Koopman Operator Theory to Legged Locomotion
… from complicated robot systems and harsh contact dynamics have long impeded the effectiveness of optimal control strategies for legged robots. In this work, we present a linearized simple walking model using Koopman Operator Theory, and its usage in Linear Model Predictive Control (L-MPC). Various …
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Intelligent Monitoring of Powerline Vibrations - Sparse Sensing and Predictive Modeling Approach
… and fail to provide real-time insights into the dynamic behavior of conductors. This thesis presents a data-driven framework for real-time monitoring and state estimation of vibration profiles in transmission lines, offering a scalable and intelligent alternative to conventional methods.The …
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Adaptive Stochastic Reduced-Order Modeling for Autonomous Ocean Platforms
… platforms, efficient adaptive reduced-order models (ROMs) are needed. In this thesis, we first review existing approaches and then develop a new adaptive Dynamic Mode Decomposition (DMD)-based, data-driven, reduced-order model framework that provides onboard forecasting and data assimilation …
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Large Eddy Simulation and Analysis of Shear Flows in Complex Geometries
… jet in crossflow). Verification of subgrid scale model is done through comparisons with measurements for a turbulent flow over back step, present cases of counter current shear and film cooling flow. In the first part, a three dimensional stability analysis is conducted for countercurrent shear …
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Unsteady Metric Based Grid Adaptation using Koopman Expansion
… to high-speed applications, demanding precise modelling to characterize their unsteady features accurately. The simulation of unsteady supersonic and hypersonic flows is inherently computationally expensive, requiring a highly refined mesh to capture these unsteady effects. While anisotropic …
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Robust and Data-Driven Uncertainty Quantification Methods as Real-Time Decision Support in Data-Driven Models
The growing complexity and data in modern engineering and physical systems require robust frameworks for real-time decision-making. Data-driven models trained on observational data enable faster predictions but face key challenges—data corruption, bias, limited interpretability, and uncertainty …
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Mathematical Modeling and Dynamic Recovery of Power Systems
Power networks are sophisticated dynamical systems whose stable operation is essential to modern society. We study the swing equation for networks and its linearization (LSEN) as a tool for modeling power systems. Nowadays, phasor measurement units (PMUs) are used across power networks to measure …
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DMD and POD Modal Analysis for Store Separation
… time in this process is the implementation of a mode based reduced order model (ROM) for modeling store separation. The objective of this study was to first identify the leading modes that can best be used to model a store separating from an aircraft. To obtain these modes, two algorithms were …
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Dynamic Estimation of Large-Scale Flow Events in Open Cavity Flows
<p>Flow over an open cavity has a dynamically complex flowfield, generating pressure fluctuations that can amplify shear stress and cause structural damage to the stores within it and the aircraft as a whole. These pressure loads are linked to large-scale resonant shear layer phenomena. …
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Measurement of combustion response to transverse modes at high pressure
… to process these data. Proper orthogonal decomposition and dynamic mode decomposition showed spatial and temporal character of image time slices sorted by descriptive content and frequency, respectively. These analyses both identified significant behavior at the same frequencies as chamber …
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Modeling and Estimation of Motion Over Manifolds with Motion Capture Data
Modeling the dynamics of complex multibody systems, such as those representing the motion of animals, can be accomplished through well-established geometric methods. In these formulations, motions take values in certain types of smooth manifolds which are coordinate-free and intrinsic. However, the …
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