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 21 for “"direct optimization"”.
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Direct optimization of 3D dose distributions using collimator rotation
… is achieved by developing and implementing a direct aperture optimization (DAO) platform where the multileaf collimator (MLC) is rotated between each aperture. The approach is referred to as rotating aperture optimization (RAO). A series of tests is performed to evaluate how a final optimized …
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Algorithmic and implementation aspects of on-line calibration of Dynamic Traffic Assignment
… The classical statespace formulation and 2) The direct optimization formulation. Extended Kalman Filter (EKF) is presented and validated under the state-space formulation. Pattern Search (PS), Conjugate Gradient Method (CG) and Gradient Descent (GD) are presented and validated under the direct …
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Interactive computer graphics in non-linear optimization.
… interactive computer graphics and non-linear optimization. The potential contribution of interactive computer graphics in nonlinear optimization is then evaluated from the points of view of model formulation and solution, and the requirements of an interactive system for realizing this …
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Learning to Trade Off Performance and Safety in Mixed Autonomy Traffic
… AVs, which have recently seen potential for direct optimization of singular system objectives, such as traffic smoothing and emission reduction, and introduces a reinforcement learning-based methodological framework to facilitate a study of the trade offs between performance and safety at a …
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Novel Inverse Airfoil Design Utilizing Parametric Equations
… A common way to think about airfoil design is optimization, the process of taking an airfoil and modifying it to improve its performance. The classic design goal is to minimize drag subject to required lift and thickness values to meet aerodynamic and structural constraints. This is typically …
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Evaluation of Radiobiological Effects in Intensity Modulated Proton Therapy : New Strategies for Inverse Treatment Planning
… which now allows simultaneous multi-field optimization of the biological effect in a reasonable time. With these methods, unfavourable RBE effects can be identified and compensated for by direct optimization of the product of RBE and dose, which is demonstrated for several clinical …
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Global Optimization of Transmitter Placement for Indoor Wireless Communication Systems
The DIRECT (DIviding RECTangles) algorithm JONESJOTi, a variant of Lipschitzian methods for bound constrained global optimization, has been applied to the optimal transmitter placement for indoor wireless systems. Power coverage and BER (bit error rate) are considered as two criteria for optimizing …
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The Integration of State Space into the Dynamic Synthesis/Design and Operational/Control Optimization of a PEMFC System
A typical approach to the synthesis/design optimization of energy systems is to only use steady state operation and high efficiency (or low total life cycle cost) at full load as the basis for the synthesis/design. Transient operation is a secondary task to be solved by system and control engineers …
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Automated Process Planning for Five-Axis Point Milling of Sculptured Surfaces
… process planning was carefully planned out, with optimization and improvements in the following areas: Firstly, a new representation scheme for the accessible posture range of a cutter at a surface point, called boundary posture chain, is proposed. With this new formation, the accessible posture …
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Improved collocation methods with application to direct trajectory optimization
… control problems. These methods are used in direct optimization methods where the original optimal control problem formulation is converted to a nonlinear programming problem. This conversion is performed by first discretizing the solution time history using parameters to represent discrete …
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Integer optimization methods for machine learning
In this thesis, we propose new mixed integer optimization (MIO) methods to ad- dress problems in machine learning. The first part develops methods for supervised bipartite ranking, which arises in prioritization tasks in diverse domains such as information retrieval, recommender systems, natural …
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Design and Optimization of Nanoplasmonic Waveguide Devices
… originally developed for microwave circuit optimization, can enable the efficient design of nanoplasmonic waveguide devices which satisfy a set of desired specifications. Space mapping utilizes a physics-based coarse model to approximate a fine model accurately describing a device. Here the …
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Phylogenetic Systematics and Evolution within the Family Scincidae
… colonizations from Africa to the New World. Direct Optimization (DO) is compared with traditional alignment methods, and multilocus maximum likelihood and Bayesian methods are used to date divergence times within the group. Results show that DO consistently finds more optimal tree topologies …
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Optimal pumping policy for a public supply wellfield using computational neural network with decision-making methodology
… flow equations, was embedded into a linear optimization program, and an objective function that quantified both risk and supply was solved for using different weight preferences. The resulting Pareto frontier served as the basis for multiobjective and conflict resolution analyses. The CNN …
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I. Kinetic Modeling of Surface Reactions II. Computational Design of Organic Semiconductors
… space, and then we examine the potential of direct optimization to maximize the TADF rate. Second, we investigate the role of ISC in enhancing the efficiencies of TTA upconverters. We present computational evidence that the limit-breaking TTA efficiencies of certain annihilators might be …
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Phylogeny of the Polyneopterous Insects With Emphasis on Plecoptera: Molecular and Morpological Evidence
… Mantophasmatodea. Our results also suggest the Direct Optimization (formerly Optimization Alignment) produces alignments that are more predictable across the parameter landscape than alignment via CLUSTAL X, as measured by congruence among independent data partitions. Dense taxon sampling and …
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A Non-Parametric Framework for Value-Based Individualized Treatment Rule Estimation
… interpretable ITRs using decision trees with a direct optimization purity measure proposed for each type of outcome. An interpretable ITR framework is developed for a typical univariate, continuous outcome with a binary treatment, extended to a risk constrained optimizer, and additionally …
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River network scaling: optimality and anisotropy
… of an overall network is the result of direct optimization. Global constraint optimality is the truly controversial variety. I show that the success of global constraint theories is likely due to the optimization algorithm employed rather than to the optimality constraint itself. There …
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Probabilistic optimization of vibrational systems under stochastic excitation containing extreme forcing events
… involving the solution of a low-dimensional optimization problem. The method is also assessed in higher-dimensional problems involving linear elastic rods coupled to a nonlinear energy harvester. In the second part of this thesis, we consider the problem of mechanical systems excited by …
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Evolution and phylogeny of basal winged insects with emphasis on mayflies (Ephemeroptera)
<p>Ephemeroptera (mayflies) is a monophyletic group of semi-aquatic pterygote insects, comprising 3083 species, 376 genera, and 37 described families and are present on all continents, excluding Antarctica, being associated with freshwater and brackish water habitats. The order is unique among …
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