Physical Sciences and Mathematics Commons^™

Impact Of Hillslope-Scale Organization Of Topography, Soil Moisture, Soil Temperature, And Vegetation On Modeling Surface Microwave Radiation Emission, Alejandro N. Flores, Valeriy Y. Ivanov, Dara Entekhabi, Rafael L. Bras

Geosciences Faculty Publications and Presentations

Microwave radiometry will emerge as an important tool for global remote sensing of near-surface soil moisture in the coming decade. In this modeling study, we find that hillslopescale topography (tens of meters) influences microwave brightness temperatures in a way that produces bias at coarser scales (kilometers). The physics underlying soil moisture remote sensing suggests that the effects of topography on brightness temperature observations are twofold: 1) the spatial distribution of vegetation, moisture, and surface and canopy temperature depends on topography and 2) topography determines the incidence angle and polarization rotation that the observing sensor makes with the local land surface. …

Analytical And Computational Studies Of Magneto-Convection In Solidifying Mushy Layer, Mallikarjunaiah Siddapura Muddamallappa

Theses and Dissertations - UTB/UTPA

Natural convection in solidifying binary media is of great interest due to it's applications in material processing and crystal growth industries. Convective flows between the layers of melt during alloy solidification is known to produce mechanical imperfections such as freckle's. Hence it is important to investigate the criterion for freckling and discover the means of suppressing it. A mushy layer, which has both solid and fluid components and is formed between underlying solid and overlying liquid, is known to produce chimneys, which are narrow, vertical vents, devoid of solid. We consider the problem of magneto-convection in a horizontal mushy layer …

Effects Of Adding An Enhanced Material Instructional Model To A Collaborative Grouping Instructional Strategy In A College Preparatory Chemistry Course, Chinyere Fidelia Shaw-Nnajiofor

Theses and Dissertations - UTB/UTPA

This research study investigated comparable academic achievement outcomes between an experimental group (EG) and a control group (CG) in a college preparatory chemistry course using a mixture of instructional pedagogies. The subjects comprised native and non-native English speakers, often identified as Limited English Proficiency (LEP) students. The study found no statistically significant difference between the pre-test scores of EG and CG students and a significant difference between the post-test scores of students in the experimental group compared to those of the control group. No significant difference was observed when comparing the test scores of the post-tests of the LEP-EG students …

Two-Dimensional Wigner-Ville Transforms And Their Basic Properties, Bheemaiah Veena Shankara Narayana Rao

Theses and Dissertations - UTB/UTPA

This thesis deals with Wigner-Ville transforms and their basic properties. The Wigner-Ville transforms are a non-linear transform which constitute an important tool in nonstationary signal analysis. Wigner-Ville transforms in one dimension and their basic properties are discussed here. Special attention is given to formulation of two dimensional Wigner-Ville transform, its inversion formula and some of their basic properties. Some applications of Wigner-Ville transforms are also briefly discussed.

Integrable Equations With Non-Smooth Solitons, Xianqi Li

Theses and Dissertations - UTB/UTPA

In this thesis, we present a class of integrable equations with non-smooth soliton solutions. In particular, we derive the bi-Hamiltonian structure and Lax pair of the equation pt = bux + \[{u2 — u1)p]x,p = u — uxx, which guarantee its integrability. Another interesting integrable equation we study is (=Jff!i)t = 2uux, which is exactly the first member of the negative KdV hierarchy. Through traveling wave setting arid phase step analysis, we obtain non-smooth soliton solutions of these integrable equations under different boundary condition at infinities. These equations were shown to have peaked soliton (peakon), "W/M-shape" peakon or cusped soliton …

A Dna Approach To The Road-Coloring Problem, Arindam Roy

Theses and Dissertations - UTB/UTPA

The Road-Coloring Problem in graph theory can be stated as follows: Is any irreducible aperiodic directed graph with constant outdegree 2 road-colorable? In other words, does such a graph have a synchronizing instruction? That is to say: can we label (or color) the two outgoing edges at each vertex, one with “b” or blue color and the other with “r” or red color, in such a manner that there will be an instruction in the form of a finite sequence in “b”s and “r”s (example: rrbrbbbr) such that this instruction will lead each vertex to the same “target” vertex? This …

Small And Large Scale Limits Of Multifractal Stochastic Processes With Applications, Jennifer Laurie Sinclair

Doctoral Dissertations

Various classes of multifractal processes, that is processes that display different properties at different scales, are studied. Most of the processes examined in this work exhibit stable trends at small scales and Gaussian trends at large scales, although the opposite can also occur. Many natural phenomena exhibit a fractal structure depending on some scaling factor, such as space or time. Thus, these types of processes have many useful modeling applications, including Biology and Economics. First, generalized tempered stable processes are defined and studied, following the original work on tempered stable processes by Jan Rosinski [16]. Generalized tempered stable processes encompass …

Two-Step Variations For Processes Driven By Fractional Brownian Motion With Application In Testing For Jumps From The High Frequency Data, Shiying Si

Doctoral Dissertations

In this dissertation we introduce the realized two-step variation of stochastic processes and develop its asymptotic theory for processes based on fractional Brownian motion and on more general Gaussian processes with stationary increments. The realized two-step variation is analogous to the realized 1, 1-order bipower variation introduced by Barndorff-Nielsen and Shephard [8] but mathematically is simpler to deal with. The powerful techniques of Wiener/Itˆo/Malliavin calculus for establishing limit laws play a key rule in our proofs. We include some stochastic simulations as an illustration of our theory. As a result of our study, we provide test statistics for testing for …

Hardware-Assisted Secure Computation, Alexander Iliev

Dartmouth College Ph.D Dissertations

The theory community has worked on Secure Multiparty Computation (SMC) for more than two decades, and has produced many protocols for many settings. One common thread in these works is that the protocols cannot use a Trusted Third Party (TTP), even though this is conceptually the simplest and most general solution. Thus, current protocols involve only the direct players---we call such protocols self-reliant. They often use blinded boolean circuits, which has several sources of overhead, some due to the circuit representation and some due to the blinding. However, secure coprocessors like the IBM 4758 have actual security properties similar to …

Classification And Energetics Of The Base-Phosphate Interactions In Rna, Craig L. Zirbel, Judit E. Šponer, Jiri Šponer, Jesse Stombaugh, Neocles B. Leontis

Chemistry Faculty Publications

Structured RNA molecules form complex 3D architectures stabilized by multiple interactions involving the nucleotide base, sugar and phosphate moieties. A significant percentage of the bases in structured RNA molecules in the Protein Data Bank (PDB) hydrogen-bond with phosphates of other nucleotides. By extracting and superimposing base-phosphate (BPh) interactions from a reduced-redundancy subset of 3D structures from the PDB, we identified recurrent phosphate-binding sites on the RNA bases. Quantum chemical calculations were carried out on model systems representing each BPh interaction. The calculations show that the centers of each cluster obtained from the structure superpositions correspond to energy minima on the …

Pinpointing The Extent Of Electronic Delocalization In The Re(I)-To-Tetrazine Charge-Separated Excited State Using Time-Resolved Infrared Spectroscopy, Guifeng Li, Kumar Parimal, Shubham Vyas, Christopher M. Hadad, Amar H. Flood, Ksenija D. Glusac

Chemistry Faculty Publications

Femtosecond mid-IR transient absorption spectroscopy (TRIR) and time-dependent density functional theory (TD-DFT) calculations on Re(CO)(3)Cl(Me(2)BPTZ) [Me(2)BPTZ = 3,6-bis(5-methyl-2-pyridine)-1,2,4,5-tetrazine] are used to demonstrate that the lowest excited state of the complex is a triplet metal-to-ligand charge-transfer ((3)MLCT) state with a lifetime of 225 ps. The short excited-state lifetime is explained by the energy-gap taw. Vibrational cooling of the (3)MLCT state shows up as early-time dynamics (3.6 ps). The structural changes in the excited state are deduced from the frequency shifts in the TRIR vibrational bands. The vibrational frequencies of the CO groups increase upon excitation as a result of decreased back-bonding …

An Empirical Investigation Of Filter Attribute Selection Techniques For Software Quality Classification, Kehan Gao, Taghi M. Khoshgoftaar, Huanjing Wang

Computer Science Faculty Publications

Attribute selection is an important activity in data preprocessing for software quality modeling and other data mining problems. The software quality models have been used to improve the fault detection process. Finding faulty components in a software system during early stages of software development process can lead to a more reliable final product and can reduce development and maintenance costs. It has been shown in some studies that prediction accuracy of the models improves when irrelevant and redundant features are removed from the original data set. In this study, we investigated four filter attribute selection techniques, Automatic Hybrid Search (AHS), …

Mechanisms For Temporal Change In Phytoplankton Composition In San Luis Obispo Bay California, Marc T. Tognazzini

Master's Theses

Coastal topography and more specifically, the impact of local hydrography can significantly influence phytoplankton dynamics along the California coast. In San Luis Obispo Bay California, the local hydrography is influenced by the presence of a lee and proposed upwelling shadow in the northwest corner of the bay. These conditions allow for periods of unperturbed phytoplankton growth creating phytoplankton incubation areas. Phytoplankton dynamics including accumulation, advection, and composition were examined in San Luis Obispo Bay California from January to June 2004 using all the primary techniques of ocean monitoring encompassed in the coastal module of the Global Ocean Observing System. These …

A Study For Scalable Directory In Parallel File Systems, Yang Wu

All Theses

One of the challenges that the design of parallel file system for
HPC(High Performance Computing) has to face today is maintaining the
scalability to handle the I/O generated by parallel applications that
involve accessing directories containing a large number of entries and
performing hundreds of thousands of operations per second. Currently,
highly concurrent access to large directories is poorly supported in
parallel file systems. As a result, it is important to build a
scalable directory service for parallel file systems to support
efficient concurrent access to larger directories.
In this thesis we demonstrate a scalable directory service designed
for parallel …

A Spectroscopic Analysis Of V505 Persei And The Origin Of The Lithium Dip, Patrick Baugh

All Theses

We study the observed Li Dip in stellar clusters and field stars, testing Rotationally Induced Mixing (RIM) by measuring Li abundances in a middle-aged (1.1±0.15 Gyr), metal poor ([Fe/H]=-0.15±0.03), short period binary, V505 Per, finding Li abundances of Log N(Li)=2.67±0.1 and 2.42±0.2 from the primary and secondary components, respectively. These abundances are significantly higher than observed abundances from single stars of similar metallicity and ZAMS T_eff; as shown by comparison with NGC 752, and suggest that RIM may be a primary cause of the Li Dip.

Sparse Representations In Power Systems Signals, Jack Cooper

All Theses

This thesis seeks to detect transient disturbances in power system signals in a sparse framework. To this end, an overcomplete wavelet packet dictionary and damped sinusoid dictionary are considered, and for each dictionary Matching Pursuit is compared with Basis Pursuit. Previous work in developing waveform dictionary theory and sparse representation is reviewed, and simulations are run on a test signal in both noisy and noiseless environments. The solutions are viewed as time-frequency plane tilings to compare the accuracy and sparsity of these algorithms in properly resolving optimal representations of the disturbances. The advantages and disadvantages of each combination of dictionary …

Accurate Tracking Of Objects Using Level Sets, Nalin Senthamil

All Theses

Our current work presents an approach to tackle the challenging task of tracking objects in Internet videos taken from large web repositories such as YouTube. Such videos more often than not, are captured by users using their personal hand-held cameras and cellphones and hence suffer from problems such as poor quality, camera jitter and unconstrained lighting and environmental settings. Also, it has been observed that events being recorded by such videos usually contain objects moving in an unconstrained fashion. Hence, tracking objects in Internet videos is a very challenging task in the field of computer vision since there is no …

Phenomenological Investigation Of The Effectiveness Of A Cooperative Problem-Based Laboratory And A Metacognitive Problem-Solving Exercise, Todd Gatlin

All Theses

Problem-solving has been described by many as the most important goal of chemistry teaching and learning. Solving real problems requires not only cognitive abilities but also a regulation of those abilities-metacognition. In fact, metacognition is recognized as having considerable impact on problem-solving success and learning. Recent research focused on the development of interventions designed to enhance the use of metacognition. The main objective of this study was to determine 'how' and 'why' two interventions were effective in increasing students' metacognitive use, and problem-solving abilities. Therefore, this study represents the qualitative portion of a sequential explanatory mixed-methods study; Qualitative evidence was …

Analysis Of The Neutral Wind Profiles From The Hex Ii Experiment, Tyler Scott

All Theses

The HEX II sounding rocket experiment was carried out on February 14, 2007, during active geomagnetic conditions. Three rockets released trimethyl aluminum (TMA) chemical tracer trails to measure the neutral winds. Three neutral wind profiles obtained from the upleg trails are presented. The profiles are characterized by a strong wind peak around 113 km altitude in the northwestward direction. Below the peak, the winds exhibit strong shear and a smaller wind peak at around 103 km in the southeastward direction. The wind magnitudes are too strong to be attributed to tidal forcing. Above 120 km the winds are consistently to …

Portfolio Selection Problem Under Uncertainty And Risk, Dimitri Nowak

All Theses

The purpose of this research is the investigation of a portfolio problem in an uncertain environment. Given possible investments with random performance depending on uncertain environmental settings the objective is to establish a methodology for construction of a portfolio which is non-dominated with respect to second order stochastic dominance and whose return distribution is preferable for a least risk decision maker.

Deploying And Maintaining A Campus Grid At Clemson University, Dru Sepulveda

All Theses

Many institutions have all the tools needed to create a local grid that aggregates commodity compute resources into an accessible grid service, while simultaneously maintaining user satisfaction and system security. In this thesis, the author presents a three-tiered strategy used at Clemson University to deploy and maintain a grid infrastructure by making resources available to both local and federated remote users for scientific research. Using this approach virtually no compute cycles are wasted. Usage trends and power consumption statistics collected from the Clemson campus grid are used as a reference for best-practices. The loosely-coupled components that comprise the campus grid …

Synthesis Of Polymers Featuring Novel Diphosphines, Eleanor Tennyson

All Theses

This report details the synthesis of functionalized platinum-based metallopolymers featuring m-terphenyl-scaffolded and light-harvesting phosphine ligands. Substituents placed on both the phosphine and pendant alkynyl units can enhance the optical activity of the metallopolymers depending on their inherent properties. The presence of the platinum metal atom can be exploited to increase conductivity of the molecule and promises to be a unique and valuable modification for polymers to be used in light emitting diodes and photovoltaics. Light-harvesting phosphines prepared in the course of the metallopolymer development have also been used to prepare luminescent polyelectrolytes that prove valuable for well-defined composite film formation …

Topology Control Using Joint Power And Beam-Width Control In Hybrid Rf/Fso Mesh Networks, Osama Awwad

Dissertations

Most wireless networks are deployed strictly in the radio frequency (RF) domain, since RF channels provide natural support for radial broadcast operations. However, the downside of RF channels is that they introduce many limiting externalities that make providing scalable quality of service (QoS) support difficult, if not intractable. These well-known technical challenges include bandwidth scarcity, lack of security, high interference, and high bit error rates.

Faced with such daunting obstacles to QoS, the use of Free Space Optics (FSO) for wireless communications has been proposed in which it has the potential to support higher link data rates compared to present …

On Efficient Mutual Nearest Neighbor Query Processing In Spatial Databases, Yunjun Gao, Baihua Zheng, Gencai Chen, Qing Li

Research Collection School Of Computing and Information Systems

This paper studies a new form of nearest neighbor queries in spatial databases, namely, mutual nearest neighbour (MNN) search. Given a set D of objects and a query object q, an MNN query returns from D, the set of objects that are among the k₁ (≥ 1) nearest neighbors (NNs) of q; meanwhile, have q as one of their k₂(≥ 1) NNs. Although MNN queries are useful in many applications involving decision making, data mining, and pattern recognition, it cannot be efficiently handled by existing spatial query processing approaches. In this paper, we present …

Game Action Based Power Management For Multiplayer Online Game, Bhojan Anand, A. L. Ananda, Mun Choon Chan, Long Thanh Le, Rajesh Krishna Balan

Research Collection School Of Computing and Information Systems

Current mobile devices embrace a wide range of functionalities including high speed network support, hardware accelerated 3D graphics, and multimedia capabilities. These capabilities have boosted the interest for enabling multiplayer online games (MOG) support on such devices. However, the lack of similar growth in battery technology limits the usability of these devices for MOGs. In this paper, we present energy conservation techniques for highly interactive MOGs. These are games, such as first-person shooters, where crisp user interaction is paramount to the overall game experience. Hence, conserving energy while preserving crisp user interaction becomes a critical consideration in this domain. We …

Room Temperature Tunable Energy Transfer Systems In Different Solvents, Zhonghua Guo

Electronic Theses and Dissertations

The focus of this thesis is on d⁸ and d¹⁰ metal-metal interactions, e.g. weak bonding in homometallic and heterometallic systems in liquid solutions, the tunability of luminescent energy due to the variation of metal-metal interaction strength in different solvents and different concentrations, as well as energy transfer from the luminescent energy tunable d⁸ and d¹⁰ metal ions clusters as donor ions to the lanthanide ions as acceptor ions at room temperature. First, energy transfer has been studied between dicyanoaurate(I) luminescent nanocluster donor ions and Eu³⁺ and Tb³⁺ acceptor ions in aqueous solutions. The emission …

Multilayer Image Inpainting Approach Based On Neural Networks, Quan Wang, Zhaoxia Wang, Che Sau Chang, Ting Yang

Research Collection School Of Computing and Information Systems

This paper describes an image inpainting approach based on the self-organizing map for dividing an image into several layers, assigning each damaged pixel to one layer, and then restoring these damaged pixels by the information of their respective layer. These inpainted layers are then fused together to provide the final inpainting results. This approach takes advantage of the neural network's ability of imitating human's brain to separate objects of an image into different layers for inpainting. The approach is promising as clearly demonstrated by the results in this paper.

Solar Variability And Climate Processes: The Influence Of Fluctuating Solar Spectral Irradiance On Differential Surface Heating As A Function Of Soil Geochemistry And Radiation Absorption Characteristics, Susan Wahl

Theses and Dissertations

The influence of solar variability on climate has received increasing attention. Much of the research has dealt with fluctuating ultraviolet radiation and its effects in the stratosphere; decadal signatures in cloud cover and their relationship to cosmic rays; and correlations of surface air temperature with various proxies (e.g., sunspot numbers; 10Be from ice cores and marine sediments). Much of the research has focused on changing solar radiation within the upper atmosphere and the propagating effects into the troposphere. However, there is a missing component involving differential surface heating as a function of soil composition and corresponding spectral radiation absorption properties …

Holocene History Of The East Antarctic Ice Sheet Environmental Magnetic Record From Mac. Robertson Land, Kenneth R. Kacperowski Jr.

Theses, Dissertations and Culminating Projects

A 24-m jumbo-piston core containing a 14 ka Holocene-Late Pleistocene sedimentary record was collected from Mac.Robertson Land during United States Antarctic Program cruise NBP01-01. This study uses environmental magnetism to trace the Holocene history of the East Antarctic Ice Sheet (EAIS), which is generally thought of as stable since it is grounded above sea level. Magnetic analyses are used to identify periods of terrigenous sedimentation from the EAIS, for example ice rafted debris layers or meltwater pulses. Terrigenous material contains magnetic minerals, which we expect to stand out from the dominantly biosiliceous sediment deposited along the East Antarctic Margin. Magnetic …

Countable Groups As Fundamental Groups Of Compacta In Four-Dimensional Euclidean Space, Ziga Virk

Doctoral Dissertations

This dissertation addresses the question of realization of countable groups as funda- mental groups of continuum. In first chapter we discuss classical realizations in the category of CW complexes. We introduce Eilenberg-Maclane spaces and their topological properties. The second chapter provides recent developments on realization question such as those of Shelah, Keesling, ... The third chapter proves the realization theorem for countable groups. The re- sulting space is compact path connected, connected subspace of four dimensional Euclidean space.