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Articles 511 - 540 of 1402
Full-Text Articles in Physical Sciences and Mathematics
Assessing And Modeling Community Resilience To Coastal Hazards Using A Bayesian Network, Heng Cai
Assessing And Modeling Community Resilience To Coastal Hazards Using A Bayesian Network, Heng Cai
LSU Doctoral Dissertations
This dissertation presents the assessment and modeling of community resilience to coastal hazards in the Lower Mississippi River Basin (LMRB) in southeastern Louisiana at the census block group scale. The first part is to provide a quantitative method to assess and validate the community resilience index to coastal hazards and identify the relationships between a set of socio-environmental indicators and community resilience. The Resilience Inference Measurement (RIM) model was applied to assess the resilience of the block groups. The resilience index derived was empirically validated through two statistical procedures: K-means cluster analysis of three variables (exposure, damage, and recovery) to …
Succinct Data Structures For Parameterized Pattern Matching And Related Problems, Arnab Ganguly
Succinct Data Structures For Parameterized Pattern Matching And Related Problems, Arnab Ganguly
LSU Doctoral Dissertations
Let T be a fixed text-string of length n and P be a varying pattern-string of length |P| <= n. Both T and P contain characters from a totally ordered alphabet Sigma of size sigma <= n. Suffix tree is the ubiquitous data structure for answering a pattern matching query: report all the positions i in T such that T[i + k - 1] = P[k], 1 <= k <= |P|. Compressed data structures support pattern matching queries, using much lesser space than the suffix tree, mainly by relying on a crucial property of the leaves in the tree. Unfortunately, in many suffix tree variants (such as parameterized suffix tree, order-preserving suffix tree, and 2-dimensional suffix tree), this property does not hold. Consequently, compressed representations of these suffix tree variants have been elusive. We present the first compressed data structures for two important variants of the pattern matching problem: (1) Parameterized Matching -- report a position i in T if T[i + k - 1] = f(P[k]), 1 <= k <= |P|, for a one-to-one function f that renames the characters in P to the characters in T[i,i+|P|-1], and (2) Order-preserving Matching -- report a position i in T if T[i + j - 1] and T[i + k -1] have the same relative order as that of P[j] and P[k], 1 <= j < k <= |P|. For each of these two problems, the existing suffix tree variant requires O(n*log n) bits of space and answers a query in O(|P|*log sigma + occ) time, where occ is the number of starting positions where a match exists. We present data structures that require O(n*log sigma) bits of space and answer a query in O((|P|+occ) poly(log n)) time. As a byproduct, we obtain compressed data structures for a few other variants, as well as introduce two new techniques (of independent interest) for designing compressed data structures for pattern matching.
Numerical Study Of The Periodic Anderson Model With Holstein Phonons For The Description Of Cerium Volume Collapse, Enzhi Li
LSU Doctoral Dissertations
The volume collapse transition of Cerium has intrigued physicists since its discovery several decades ago. Various models and mechanisms have been proposed, the most prominent scenarios are based on the Mott transition and the Kondo volume collapse transition. In this study, we explore the volume collapse by a dynamical mean field theory (DMFT) study of the periodic Anderson model with electron-phonon coupling to the conduction band. This allows us to study the effect of the electron-phonon interaction on the volume collapse. In order to faithfully account for the volume collapse, we also include the effects due to the volume and …
Extraction Of Displacement Fields In Heterogeneous Media Using Optimal Local Basis Functions, Paul Derek Sinz
Extraction Of Displacement Fields In Heterogeneous Media Using Optimal Local Basis Functions, Paul Derek Sinz
LSU Doctoral Dissertations
The Multiscale Spectral Generalized Finite Element Method (MS-GFEM) was developed in recent work by Babuska and Lipton. The method uses optimal local shape functions, optimal in the sense of the Kolmogorov n-width, to approximate solutions to a second order linear elliptic partial differential equation with L-infinity coefficients. In this dissertation an implementation of MS-GFEM over a two subdomain partition of unity is outlined and several numerical experiments are presented. The method is applied to compute local fields inside high contrast particle suspensions. The method's performance is evaluated for various examples with different contrasts between reinforcement particles and matrix material. The …
A Graph-Based Taxonomic Intelligent Tutoring System Utilizingbloom’S Taxonomy And Item-Response Theoretic Assessment, Dennis Gordon Castleberry Ii
A Graph-Based Taxonomic Intelligent Tutoring System Utilizingbloom’S Taxonomy And Item-Response Theoretic Assessment, Dennis Gordon Castleberry Ii
LSU Doctoral Dissertations
This dissertation details an intelligent tutoring system which aims to raise student trait abilities across concepts and levels of Blooms taxonomy within an educational program. The system utilizes Item Response Theory, a probabilistic theory of assessment which accounts for item discrimination, difficulty, and probability of guessing in its assessment of student trait ability. A modification to Item Response Theory which accounts for question dependencies is used to assess the probability that a student will answer a given question correctly given prior responses on the dependency questions. It also draws from theories of memory and forgetting present in the ACT-R model …
Branch And Stem Growth As Affected By Loss Of Leaf Area On Selected Branches In Loblolly Pine, Shannon Dumo Kidombo
Branch And Stem Growth As Affected By Loss Of Leaf Area On Selected Branches In Loblolly Pine, Shannon Dumo Kidombo
LSU Doctoral Dissertations
Leaf area and crown dynamics control how trees grow through their supply of carbohydrates and growth regulators, and their influence on tree mechanical stability. The influence of leaf area and crown dynamics to tree growth was investigated by testing the interdependence between leaf area, branch, and stem growth on young loblolly pine trees. The objectives were to (1) determine the influence of current and previous year’s leaf area on elongation of branches; (2) describe and test a unique way of quantitatively measuring the effect of neighbor branches on net growth of a target branch; (3) quantify the growth impact of …
Exact Numerical Study Of Disordered Systems, Conrad Wilson Moore
Exact Numerical Study Of Disordered Systems, Conrad Wilson Moore
LSU Doctoral Dissertations
This thesis presents work on the development of new techniques to study the problem of localization in various models of disordered systems with the goal of being able to extend these model calculations to real materials where these various mechanisms of disorder can all be present. I consider the Anderson Model with diagonal, off-diagonal disorder, multiple bands and superconductivity is included at the level of a Bogoliubov - De Gennes mean field (superconductivity is considered by adding the symmetries of the Bogoliubov - De Gennes Hamiltonian on top of the disordered lattice Hamiltonian). The localization of electrons is studied with …
Revisions To Rainfall Intensity Algorithms In Przm5.0 To Improve Estimates Of Off-Field Runoff, Eroded Sediment And Pesticide Mass, Tammara Levey Estes
Revisions To Rainfall Intensity Algorithms In Przm5.0 To Improve Estimates Of Off-Field Runoff, Eroded Sediment And Pesticide Mass, Tammara Levey Estes
LSU Doctoral Dissertations
The Environmental Protection Agency (EPA) model Pesticide Root Zone Model, version 5.0 (PRZM5.0) is used to estimate off-field loadings of pesticide concentrations in runoff and eroded sediment. Climate change has resulted in an increase in rainfall intensity patterns for much of the United States. This change impacts off-field runoff and eroded sediment as well as off-field pesticide loads from agricultural fields. Thus, the PRZM5.0 EPA “lookup” table for runoff curve numbers and the internal algorithm for eroded sediment estimation have become outdated since both temporal and geographical conditions have changed. This research presents (1) a revised method for estimating runoff …
Moduli Spaces Of Flat Gsp-Bundles, Neal David Livesay
Moduli Spaces Of Flat Gsp-Bundles, Neal David Livesay
LSU Doctoral Dissertations
A classical problem in the theory of differential equations is the classification of first-order singular differential operators up to gauge equivalence. A related algebro-geometric problem involves the construction of moduli spaces of meromorphic connections. In 2001, P. Boalch constructed well-behaved moduli spaces in the case that each of the singularities are diagonalizable. In a recent series of papers, C. Bremer and D. Sage developed a new approach to the study of the local behavior of meromorphic connections using a geometric variant of fundamental strata, a tool originally introduced by C. Bushnell for the study of p-adic representation theory. Not only …
Empirically Tuning Hpc Kernels With Ifko, Md Majedul Haque Sujon
Empirically Tuning Hpc Kernels With Ifko, Md Majedul Haque Sujon
LSU Doctoral Dissertations
iFKO (iterative Floating point Kernel Optimizer) is an open-source iterative empirical compilation framework which can be used to tune high performance computing (HPC) kernels. The goal of our research is to advance iterative empirical compilation to the degree that the performance it can achieve is comparable to that delivered by painstaking hand tuning in assembly. This will allow many HPC researchers to spend precious development time on higher level aspects of tuning such as parallelization, as well as enabling computational scientists to develop new algorithms that demand new high performance kernels. At present, algorithms that cannot use hand-tuned performance libraries …
Quaternary River Erosion, Provenance, And Climate Variability In The Nw Himalaya And Vietnam, Tara Nicole Jonell
Quaternary River Erosion, Provenance, And Climate Variability In The Nw Himalaya And Vietnam, Tara Nicole Jonell
LSU Doctoral Dissertations
The influence of Quaternary climate variation on sediment generation, storage, and transport in two mountainous Asian river basin was examined in the largest tributary to the upper Indus River in the Himalayan rain shadow, the Zanskar River basin (~15,000 km2), and the smaller, subtropical Song Gianh basin (<3,500 km2) of central Vietnam. Spatial patterns of erosion in the Zanskar River Basin were established to quantify the dominant controls on Quaternary sedimentation in the Himalayan rain shadow on the edge of the Tibetan Plateau. Glacial erosion and precipitation along the High Himalaya together dominate sediment production and transport …
Design, Synthesis, Characterization And Evaluation Of Near Infrared Bodipy Dyes For Various Applications, Qianli Meng
Design, Synthesis, Characterization And Evaluation Of Near Infrared Bodipy Dyes For Various Applications, Qianli Meng
LSU Doctoral Dissertations
4,4-Difluoro-4-bora-3a,4a-diaza-5-indacene (BODIPY) have drawn a large number of research attention, for its numerous useful application in the fields of material and biology. Small modification of this well-known fluophore has been shown to optimize its photophysical and chemical properties. This work mainly focuses on functionalization of BODIPY cores with halogenated atoms, particularly iodine, and their subsequent post-functionalization reactions, mainly cross-coupling reaction and substitutions, for various further applications. Chapter 1 of this dissertation gives a general overview of BODIPYs including their synthetic strategies, post-functionalization, and how BODIPYs are utilized in many biological applications. Chapter 2 mainly focuses on the synthesis and characterization …
Ex-Companions Of Supernovae Progenitors, Zhichao Xue
Ex-Companions Of Supernovae Progenitors, Zhichao Xue
LSU Doctoral Dissertations
Supernovae (SNe) are titanic explosions that end the life of stars. Fast expanding ejecta can create brightness that is comparable to the entire luminosity of the host galaxy for weeks. Eventually, the ejecta run into the ambient medium, creating the so-called supernova remnant (SNR) that fades away in ~ 10,000 years. SNe come from two completely different mechanisms. The Type Ia SNe (SNIa) are powered by thermonuclear runaway when a white dwarf (WD) in a binary system accretes enough mass from a companion star. The Core Collapse supernovae (CCSNe) are massive stars that run out of fuel at the end …
Condition Of Birds In Amazonian Rainforest Fragments And Second-Growth Forests, Angelica Maria Hernandez Palma
Condition Of Birds In Amazonian Rainforest Fragments And Second-Growth Forests, Angelica Maria Hernandez Palma
LSU Doctoral Dissertations
Deforestation modifies otherwise intact expanses of forest into small, isolated fragments. In addition to fragmentation, deforestation also creates abrupt forest edges and large areas of regenerating vegetation where land is abandoned after clearing. Understanding how changes in the landscape affect the physical condition of birds is crucial for managing populations in human-modified landscapes. Here I use the biomarkers feather growth rate and feather quality (ptilochronology), fluctuating asymmetry (FA), and stress hormones from feathers (CORT), to estimate the physical condition of Amazonian understory birds living in forest fragments, second-growth forests, and continuous forests. Feather CORT revealed how fragmentation disrupts interspecific interactions; …
Asymptotic Formulae For Restricted Unimodal Sequences, Richard Alexander Frnka
Asymptotic Formulae For Restricted Unimodal Sequences, Richard Alexander Frnka
LSU Doctoral Dissertations
Additive enumeration problems, such as counting the number of integer partitions, lie at the intersection of various branches of mathematics including combinatorics, number theory, and analysis. Extending partitions to integer unimodal sequences has also yielded interesting combinatorial results and asymptotic formulae, which form the subject of this thesis. Much like the important work of Hardy and Ramanujan proving the asymptotic formula for the partition function, Auluck and Wright gave similar formulas for unimodal sequences. Following the circle method of Wright, we provide the asymptotic expansion for unimodal sequences with odd parts. This is then generalized to a two-parameter family of …
Fluorescent Probe Interrogation Of A Cytoprotective Cancer-Linked Oxidoreductase In Two-Dimensional Human Cell Cultures And Solid Tumor Mimics, Bijeta Prasai
LSU Doctoral Dissertations
Fluorescence molecular imaging is an emerging field with potential to aid in optically guided surgery for cancer treatment. To overcome the drawbacks of always-on fluorescent probes, such as indocyanine green, activatable fluorescent probes are being developed that allow high signal-to-background imaging for better discrimination of cancerous cells from normal cells. For activation, turn-on fluorescent probes rely on the presence of biomarkers such as antibodies, cell-surface receptors or enzymes that are highly specific to tumor cells. hNQO1 (human NAD(P)H: quinone oxidoreductase isoenzyme 1) is considered as one of such cancer-associated biomarkers that are present intracellularly in cancers of multiple origins. It …
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 …
Resonant Interactions In Strong Field Laser Physics, Seth Jacob Camp
Resonant Interactions In Strong Field Laser Physics, Seth Jacob Camp
LSU Doctoral Dissertations
We present a theoretical study of the influence of resonant enhancement on high harmonic generation for harmonics near the ionization threshold of helium and argon atoms. This is done by solving the time-dependent Schrodinger equation (TDSE) for the interaction between an atom and a driving laser pulse. By varying parameters of the driving laser pulse, we are able to identify the enhancement of harmonics resulting from multiphoton resonances between the ground state and Stark-shifted excited states of the atom. In this way, spectral and temporal signatures of resonant enhancement are identified and highlighted. We also study trajectory dynamics in HHG. …
Molecularly Imprinted Polymers For Enantiomer Separations And Biomolecular Sensors, Britney Lyn Hebert
Molecularly Imprinted Polymers For Enantiomer Separations And Biomolecular Sensors, Britney Lyn Hebert
LSU Doctoral Dissertations
Molecularly Imprinted Polymers (MIPs) encompass a wide range of applications by changing the different components, e.g. the template, crosslinker or functional monomers. Of interest among these different applications are separations and sensors. Separations by MIPs traditionally use a chiral pure template but in some cases that chiral pure template may not be available for imprinting. Using chiral (N-α-bismethacyloyl-L-alanine) and achiral (N,O-bisacrylamide ethanolamine) crosslinkers we investigated imprinting of scalemic and racemic template mixtures of Boc-tyrosine enantiomers. The achiral and chiral crosslinkers yielded similar results for the partial separation of enantiomers by scalemic imprinted polymers because separation and recognition are not dependent …
Synthesis And Characterization Of Polyhalogenated Boron Dipyrromethenes And Carboranylbisthiophene Oligomers, Ning Zhao
LSU Doctoral Dissertations
Chapter 1 of this dissertation shows a brief overview of fundamental concepts and classic synthetic routes of BODIPY dyes. The synthetic strategies and various application (e.g. PDT sensitizers and fluorescent indicators) of halogenated BODIPYs are also presented in this chapter. Chapters 2-4 describe the synthesis of three new polyhalogenated BODIPY platforms and their regioselective functionalization. Such new platforms provide new methodologies for producing both symmetric and asymmetric BODIPYs. Pd(0)-catalyzed cross-couplings and aromatic substitution reactions were applied to investigate the reactivity and regioselectivity of different halogen groups on the BODIPY platforms. The studies showed that the reactivity order of the halogens …
Design, Synthesis And Biological Applications Of Polypeptoids And Boron Dipyrromethenes, Sunting Xuan
Design, Synthesis And Biological Applications Of Polypeptoids And Boron Dipyrromethenes, Sunting Xuan
LSU Doctoral Dissertations
The dissertation is about the design, synthesis and biological applications of polypeptoids and boron dipyrromethenes (BODIPYs). The dissertation is divided into seven chapters reporting various aspects of the background to my field of study and the results obtained during my PhD program. Chapter 1 is a concise overview of the fundamental concepts of polypeptoids and hydrogels, as well as their recent developments on synthetic strategies, property investigations, and biological applications in different fields. Chapter 2 presents the design, synthesis and potential application as tissue engineering scaffold of thermoreversible ABC polypeptoid hydrogels. A series of ABC copolypeptoids were synthesized and their …
A Novel Recurrent Convolutional Neural Network For Ocean And Weather Forecasting, Robert James Firth
A Novel Recurrent Convolutional Neural Network For Ocean And Weather Forecasting, Robert James Firth
LSU Doctoral Dissertations
Numerical weather prediction is a computationally expensive task that requires not only the numerical solution to a complex set of non-linear partial differential equations, but also the creation of a parameterization scheme to estimate sub-grid scale phenomenon. The proposed method is an alternative approach to developing a mesoscale meteorological model – a modified recurrent convolutional neural network that learns to simulate the solution to these equations. Along with an appropriate time integration scheme and learning algorithm, this method can be used to create multi-day forecasts for a large region. The learning method presented is an extended form of Backpropagation Through …
Scanning Probe Investigations Of Multidentate Thiol And Spatially Confined Porphyrin Nanoassemblies Using Nanoscale Lithography, Xianglin Zhai Zhai
Scanning Probe Investigations Of Multidentate Thiol And Spatially Confined Porphyrin Nanoassemblies Using Nanoscale Lithography, Xianglin Zhai Zhai
LSU Doctoral Dissertations
Approaches to prepare spatially selective surfaces were developed in this dissertation for constructing nanopatterns of organic thin film materials. Nanoscale surface patterns were prepared using immersion particle lithography and scanning probe lithography combined with organothiol chemistry. Organic thin films and nanomaterials can be patterned with tunable periodicities and designed shapes by selecting the diameter of mesospheres used as surface masks or scanning probe lithography, respectively. The surface platforms of well-defined nanopatterns are ideal for high resolution investigations using scanning probe microscopy (SPM). Local measurements of surface properties and conductive properties combined with nanolithography were accomplished at the molecular level. Sample …
On Properties Of Matroid Connectivity, Simon Pfeil
On Properties Of Matroid Connectivity, Simon Pfeil
LSU Doctoral Dissertations
Highly connected matroids are consistently useful in the analysis of matroid structure. Round matroids, in particular, were instrumental in the proof of Rota's conjecture. Chapter 2 concerns a class of matroids with similar properties to those of round matroids. We provide many useful characterizations of these matroids, and determine explicitly their regular members. Tutte proved that a 3-connected matroid with every element in a 3-element circuit and a 3-element cocircuit is either a whirl or the cycle matroid of a wheel. This result led to the proof of the 3-connected splitter theorem. More recently, Miller proved that matroids of sufficient …
Properties Of Polynomial Identity Quantized Weyl Algebras, Jesse S. F. Levitt
Properties Of Polynomial Identity Quantized Weyl Algebras, Jesse S. F. Levitt
LSU Doctoral Dissertations
In this work on Polynomial Identity (PI) quantized Weyl algebras we begin with a brief survey of Poisson geometry and quantum cluster algebras, before using these as tools to classify the possible centers of such algebras in two different ways. In doing so we explicitly calculate the formulas of the discriminants of these algebras in terms of a general class of central polynomial subalgebras. From this we can classify all members of this family of algebras free over their centers while proving that their discriminants have the properties of effectiveness and local domination. Applying these results to the family of …
Biomass Gasification For Electricity Generation: An Integrated Approach For Development Of Forest Residue-Based Projects In Rural India, Anand Mishra
LSU Doctoral Dissertations
Biomass gasification is generally regarded as a promising technology for various advanced application in energy production. Biomass is the only carbon-based sustainable option among the renewable energy sources. This study is focused on fostering biomass gasification for electricity generation sector in India. The study addresses four broad aspects of biomass gasification for electricity generation - feedstock properties and gasification technology, policy and regulatory framework governing the sector, financial evaluation of electricity generation from biomass gasification, and feedstock supply. The study is divided in four chapters, each of which addresses one aspect of electricity generation through biomass gasification. Based on literature, …
Spectral Properties Of Photonic Crystals: Bloch Waves And Band Gaps, Robert Paul Viator Jr
Spectral Properties Of Photonic Crystals: Bloch Waves And Band Gaps, Robert Paul Viator Jr
LSU Doctoral Dissertations
The author of this dissertation studies the spectral properties of high-contrast photonic crystals, i.e. periodic electromagnetic waveguides made of two materials (a connected phase and included phase) whose electromagnetic material properties are in large contrast. A spectral analysis of 2nd-order divergence-form partial differential operators (with a coupling constant k) is provided. A result of this analysis is a uniformly convergent power series representation of Bloch-wave eigenvalues in terms of the coupling constant k in the high-contrast limit k -> infinity. An explicit radius of convergence for this power series is obtained, and can be written explicitly in terms of the …
Tip-Enhanced Laser Ablation Sample Transfer For Mass Spectrometry, Chinthaka Aravinda Seneviratne
Tip-Enhanced Laser Ablation Sample Transfer For Mass Spectrometry, Chinthaka Aravinda Seneviratne
LSU Doctoral Dissertations
In this research, atomic force microscope tip-enhanced laser ablation mass spectrometry (AFM TELA-MS), an ambient sub-micrometer scale sampling method for offline MS was developed. AFM TELA was used to transfer molecules from thin films to a suspended silver wire for off-line mass spectrometry using laser desorption ionization (LDI) and matrix-assisted laser desorption ionization (MALDI). An AFM with a 30 nm radius gold-coated silicon tip was used to image the sample and to hold the tip 15 nm from the surface for material removal using a pulsed Nd:YAG laser, which provides output at wavelengths of 532 nm in the visible, 1064 …
Thin Films Of Semiconducting Polymers And Block Copolymers By Surface-Initiated Polymerization, Sang Gil Youm
Thin Films Of Semiconducting Polymers And Block Copolymers By Surface-Initiated Polymerization, Sang Gil Youm
LSU Doctoral Dissertations
The ability to control nanoscale morphology and molecular organization in organic semiconducting polymer thin films is an important prerequisite for enhancing the efficiency of organic thin-film devices, including organic light-emitting and photovoltaic devices. The current “top-down” paradigm for making such devices is based on utilizing solution-based processing (e.g. spin-casting) of soluble semiconducting polymers. This approach typically provides only modest control over nanoscale molecular organization and polymer chain alignment. A promising alternative to using solutions of pre-synthesized semiconducting polymers pursues instead a “bottom-up” approach to prepare surface-grafted semiconducting polymer thin films by surface-initiated polymerization of small-molecule monomers. This dissertation mainly focuses …
Ecological-Hydrological Feedback In Forested Wetlands, Scott Thomas Allen
Ecological-Hydrological Feedback In Forested Wetlands, Scott Thomas Allen
LSU Doctoral Dissertations
In forested wetlands, the biotic and abiotic consequences of water level variability is not well understood. The effects of flooding on carbon and water exchanges are important knowledge gaps where progress could benefit management of natural resources and predicting of changes in surface geophysical cycles. Two specific needs are a better understanding of (1) wetland tree responses to hydrologic variations, and (2) the effects of the forest and associated tree stressors on surface energy and water fluxes. Objectives were to determine effects of flooding on evaporation rates and energy dynamics, tree water use and growth responses to river-floodplain connectivity and …