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 9 of 9 for “"Invariant Models"”.
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Model Reduction Using Semidefinite Programming
… thesis model reduction methods for linear time invariant systems are investigated. The reduced models are computed using semidefinite programming. Two ways of imposing the stability constraint are considered. However, both approaches add a positivity constraint to the program. The input to the …
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Spatiotemporal systems: gradual variations, identification, adaptation and robustness
… designed based on local linear spatiotemporally invariant (LSTI) approximants. We show that the l_infinity to l_infinity performance of global LSTV systems cannot be much worse than the worst frozen spatially and temporally l_infinity to l_infinity performance, given that the rates of variation …
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Symmetry and Other Structures: Topics in Nonparametric Regression
… key idea is to generalise sparsity, multi-index models, and other non-linear lower dimensional patterns in f in terms of transformations of the covariate space: Ψ_f ⊆ {Bijections ψ∶X→X} (1) for which f ○ ψ = f for all ψ ∈ Ψ_f . Functions that satisfy this property have Symmetry: in the same way …
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Parameterised verification of randomised distributed systems using state-based models
… we consider the application of network invariants and explicit induction to the parameterised verification of state-based models of randomised distributed systems. We demonstrate the use of network invariants by constructing invariant models for non-probabilistic and probabilistic forms …
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Disorder-Free Localization
… we introduce a family of simple translationally invariant models of fermions locally coupled to spins, which have a disorder-free mechanism for localization. This mechanism is due to a local Z$_{2}$ gauge symmetry and we uncover the connection to lattice gauge theories. We diagnose the …
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Locally Tuneable Quantum Hamiltonians with Neutral Atoms in Optical Lattices
… versatile quantum simulators of quantum lattice models with many applications. While they have successfully realised many translationally invariant models, the ability to locally tune all local Hamiltonian parameters remains an outstanding goal that would enable the simulation of a wider range of …
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Nonlinear Observers for Aircraft Maneuvering in Wind
… leveraging the fact that the system dynamics are invariant under the action of a Lie group. By using a moving frame to construct invariant observer mappings, both the design process and stability analysis are simplified. In cases where the system's nonlinearities comprise the Lie group's action, …
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Model Order Reduction Based on Semidefinite Programming
… thesis is complexity reduction of linear time-invariant models. The complexity in such systems is measured by the number of differential equations forming the dynamical system. This number is called the order of the system. Order reduction is typically used as a tool to model complex systems, …
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Scaling of entanglement entropy in some condensed matter systems
… of entanglement entropy in 2+1 dimensional scale invariant systems. Chapter 5 studies the bulk-boundary correspondence in 3 + 1 dimensional topological phases and its entanglement entropy. In chapter 2, we investigate the reduced density matrices for a model of free fermions on a two-leg ladder …