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Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model, Andrew L. Hicks
Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model, Andrew L. Hicks
LSU Doctoral Dissertations
This thesis gives an analysis of modeling and numerical issues in the Landau-de Gennes (LdG) model of nematic liquid crystals (LCs) with cholesteric effects. We derive various time-step restrictions for a (weighted) $L^2$ gradient flow scheme to be energy decreasing. Furthermore, we prove a mesh size restriction, for finite element discretizations, that is critical to avoid spurious numerical artifacts in discrete minimizers that is not well-known in the LC literature, particularly when simulating cholesteric LCs that exhibit ``twist''. Furthermore, we perform a computational exploration of the model and present several numerical simulations in 3-D, on both slab geometries and spherical …
Framework For Algorithmically Optimizing Longitudinal Health Outcomes: Examples In Cancer Radiotherapy And Occupational Radiation Protection, Lydia Joyce Wilson
Framework For Algorithmically Optimizing Longitudinal Health Outcomes: Examples In Cancer Radiotherapy And Occupational Radiation Protection, Lydia Joyce Wilson
LSU Doctoral Dissertations
Background: Advancements in the treatment of non-infectious disease have enabled survival rates to steadily increase in recent decades (e.g., diabetes, heart disease, and cancer). Epidemiological studies have revealed that the treatments for these diseases can have life-threatening and/or life–altering effects. Thus, realizing the full beneficial potential of advanced treatments necessitates new tools to algorithmically consider all major components of the health outcome, including benefit and detriment. The goal of this dissertation was to develop a framework for improving projected health outcomes following planned radiation exposures in consideration of all beneficial and detrimental, early and late, and fatal and non-fatal …
Maintaining High Performance Across All Problem Sizes And Parallel Scales Using Microkernel-Based Linear Algebra, Md Rakib Hasan
Maintaining High Performance Across All Problem Sizes And Parallel Scales Using Microkernel-Based Linear Algebra, Md Rakib Hasan
LSU Doctoral Dissertations
Linear algebra underlies a large proportion of computational problems. With the continuous increase of scale on modern hardware, performance of small sized linear algebra has become increasingly important. To overcome the shortcomings of conventional approaches, we employ a new approach using a microkernel framework provided by ATLAS to improve the performance of a few linear algebra routines for all problem sizes. Our initial research consists of improving the performance of parallel LU factorization in ATLAS for which we were able to achieve up to 2.07x and 2.66x speedup for small problems, up to 91% and 87% of theoretical peak performance …
Reformulations For Control Systems And Optimization Problems With Impulses, Jacob Blanton
Reformulations For Control Systems And Optimization Problems With Impulses, Jacob Blanton
LSU Doctoral Dissertations
This dissertation studies two different techniques for analyzing control systems whose dynamics include impulses, or more specifically, are measure-driven. In such systems, the state trajectories will have discontinuities corresponding to the atoms of the Borel measure driving the dynamics, and these discontinuities require further definition in order for the control system to be treated with the broad range of results available to non-impulsive systems. Both techniques considered involve a reparameterization of the system variables including state, time, and controls. The first method is that of the graph completion, which provides an explicit reparameterization of the time and state variables. The …
Advances In Quantum Optical Metrology And The Establishment Of An Invisible Quantum Tripwire, Steven Blane Mccracken
Advances In Quantum Optical Metrology And The Establishment Of An Invisible Quantum Tripwire, Steven Blane Mccracken
LSU Doctoral Dissertations
This thesis presents a summary of the foundation and background of the field of quantum optics, and an analysis of some recent discoveries in various fields of which I have aided in furthering investigative research and advancement through publications. Such topics include numerical optimization of generalized quantum states used in phase sensitive quantum metrology, an analysis of object detection through the use of quantum interferometry in the presence of lossy conditions, and the use of the latter technique to propose an invisible quantum tripwire. First is a collaborative effort to numerically optimize quantum optical states for quantum metrological applications. We …
The Impact Of Overfitting And Overgeneralization On The Classification Accuracy In Data Mining, Huy Nguyen Anh Pham
The Impact Of Overfitting And Overgeneralization On The Classification Accuracy In Data Mining, Huy Nguyen Anh Pham
LSU Doctoral Dissertations
Current classification approaches usually do not try to achieve a balance between fitting and generalization when they infer models from training data. Such approaches ignore the possibility of different penalty costs for the false-positive, false-negative, and unclassifiable types. Thus, their performances may not be optimal or may even be coincidental. This dissertation analyzes the above issues in depth. It also proposes two new approaches called the Homogeneity-Based Algorithm (HBA) and the Convexity-Based Algorithm (CBA) to address these issues. These new approaches aim at optimally balancing the data fitting and generalization behaviors of models when some traditional classification approaches are used. …
Experimental Design, Synthesis And Application Of Molecular Micelle Modified Polymeric Nanoparticles For Drug Delivery Systems And Free Radical Detection, Gabriela M. Ganea Visser
Experimental Design, Synthesis And Application Of Molecular Micelle Modified Polymeric Nanoparticles For Drug Delivery Systems And Free Radical Detection, Gabriela M. Ganea Visser
LSU Doctoral Dissertations
Biodegradable and biocompatible polymeric nanoparticles such as poly (lactide-co-glycolide) (PLGA) nanoparticles have been extensively studied as drug delivery systems for a variety of pharmaceutical agents. Nanoparticle surface properties are primarily determined by the emulsifiers used in the synthesis process, which have a significant impact on nanoparticle physico-chemical and biological properties. Anionic amino acid – based molecular micelles were used in the emulsification process to prepare monodisperse, small (below 100 nm) PLGA nanoparticles with a well defined spherical shape. Such molecular micelle – modified nanoparticles were used as drug carriers for delivery of antioxidants. Thymoquinone is a natural antioxidant, and an …