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Doctoral Dissertations

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Full-Text Articles in Physical Sciences and Mathematics

Machine Learning Methods For Activity Detection In Wearable Sensor Data Streams, Roy Adams Jan 2018

Machine Learning Methods For Activity Detection In Wearable Sensor Data Streams, Roy Adams

Doctoral Dissertations

Wearable wireless sensors have the potential for transformative impact on the fields of health and behavioral science. Recent advances in wearable sensor technology have made it possible to simultaneously collect multiple streams of physiological and context data from individuals in natural environments; however, extracting reliable high-level inferences from these raw data streams remains a key data analysis challenge. In this dissertation, we address three challenges that arise when trying to perform activity detection from wearable sensor streams. First, we address the challenge of learning from small amounts of noisy data by proposing a class of conditional random field models for ...


"Voltage-Driven Polyelectrolyte Complexation Inside A Nanopore, Prabhat Tripathi Jan 2018

"Voltage-Driven Polyelectrolyte Complexation Inside A Nanopore, Prabhat Tripathi

Doctoral Dissertations

This thesis investigates how a pair of oppositely charged macromolecules can be driven by an electric field to form a polyelectrolyte complex inside a nanopore. To observe and isolate an individual complex pair, a model protein nanopore, embedded in artificial phospholipid membrane, allowing compartmentalization (cis/trans) is employed. A polyanion in the cis and a polycation in the trans compartments are subjected to electrophoretic capture by the pore. We find that the measured ionic current across the pore has a distinguishable signature of complex formation, which is different from the signature of the passage of individual molecules through the pore ...


Equilibrium Partitioning Of Binary Polymer Mixtures Into Biological Nanopores, Mehmet Alphan Aksoyoglu Jan 2018

Equilibrium Partitioning Of Binary Polymer Mixtures Into Biological Nanopores, Mehmet Alphan Aksoyoglu

Doctoral Dissertations

The cell interior, enclosed by membrane barriers, is a condensed solution of inorganic ions, polymers, carbohydrates, polynucleotides, and a large number of other organic molecules. Within cells, transport of metabolites and biopolymers, such as polynucleotides and proteins, occurs partly through specific transmembrane pores (mesoscopic ion channels) spanning cellular compartments. Examples of such functions are translocation of matrix RNA molecules from cell nucleus through nuclear pore complexes, ejection of viral genome from bacterial virus capsids into host bacterial cells, and translocation of protein factors across toxin channels in biological membranes. All these processes, that occur in the cellular milieu, are mediated ...


Hybrid Black-Box Solar Analytics And Their Privacy Implications, Dong Chen Jan 2018

Hybrid Black-Box Solar Analytics And Their Privacy Implications, Dong Chen

Doctoral Dissertations

The aggregate solar capacity in the U.S. is rising rapidly due to continuing decreases in the cost of solar modules. For example, the installed cost per Watt (W) for residential photovoltaics (PVs) decreased by 6X from 2009 to 2018 (from $8/W to $1.2/W), resulting in the installed aggregate solar capacity increasing 128X from 2009 to 2018 (from 435 megawatts to 55.9 gigawatts). This increasing solar capacity is imposing operational challenges on utilities in balancing electricity's real-time supply and demand, as solar generation is more stochastic and less predictable than aggregate demand.

To address this ...


The Dissociative Chemisorption Of Methane And Its Isotopologues On Metal Surfaces, Han Guo Jan 2018

The Dissociative Chemisorption Of Methane And Its Isotopologues On Metal Surfaces, Han Guo

Doctoral Dissertations

The dissociative chemisorption of small molecules on metal surfaces is an important step in many heterogeneous catalytic processes, and has received considerable scientific attention. In this thesis, a quantum approach based on the reaction path Hamiltonian is used to explore the dissociative chemisorption of methane and its deuterated isotopologues on several metal surfaces.

The theoretical approach is described in Chapter 2. This approach treats all 15 degrees of freedom of the methane molecule, and includes the effects of lattice motion, allowing us to examine the translational and vibrational enhancements, mode- and bond-selectivity and the surface temperature dependence observed in experiments ...


Data Stream Algorithms For Large Graphs And High Dimensional Data, Hoa Vu Jan 2018

Data Stream Algorithms For Large Graphs And High Dimensional Data, Hoa Vu

Doctoral Dissertations

In contrast to the traditional random access memory computational model where the entire input is available in the working memory, the data stream model only provides sequential access to the input. The data stream model is a natural framework to handle large and dynamic data. In this model, we focus on designing algorithms that use sublinear memory and a small number of passes over the stream. Other desirable properties include fast update time, query time, and post processing time.

In this dissertation, we consider different problems in graph theory, combinatorial optimization, and high dimensional data processing.

The first part of ...


Global Well-Posedness And Scattering For The Defocusing Quintic Nonlinear Schrödinger Equation In Two Dimensions, Xueying Yu Jan 2018

Global Well-Posedness And Scattering For The Defocusing Quintic Nonlinear Schrödinger Equation In Two Dimensions, Xueying Yu

Doctoral Dissertations

In this thesis we consider the Cauchy initial value problem for the defocusing quintic nonlinear Schrödinger equation in two dimensions. We take general data in the critical homogeneous Sobolev space dot H1/2.

We show that if a solution remains bounded in dot H1/2 in its maximal time interval of existence, then the time interval is infinite and the solution scatters.


Spectroscopic Studies Of Gas-Phase Metal Cation Complexes With Alkanes And Ammonia, Muhammad Affawn Ashraf Jan 2018

Spectroscopic Studies Of Gas-Phase Metal Cation Complexes With Alkanes And Ammonia, Muhammad Affawn Ashraf

Doctoral Dissertations

Understanding the non-covalent interaction between metals and small ligands such as methane and ammonia is of key importance because of their industrial and biological applications. However, these interactions are difficult to study and quantify in the bulk phase due to the interaction with neighboring molecules or atoms. Gas phase spectroscopy of mass-selected clusters is a powerful technique that overcomes this challenge by allowing clusters with known composition to be studied in the gas phase. In this thesis, we investigate the interaction between three types of small molecular ligands with metal and metal cluster ions, and answer questions about their geometries ...


Framed Sheaves On A Quadric Surface, Nguyen Thuc Huy Le Jan 2018

Framed Sheaves On A Quadric Surface, Nguyen Thuc Huy Le

Doctoral Dissertations

We study framed sheaves on a smooth quadric surface and conjecture that the moduli of such framed sheaves admits a twistor deformation similar to one studied in the paper "Brill-Noether duality for moduli spaces of sheaves on K3 surfaces" by Markman.


Photofragment Imaging Fast Ion Beams, Michael D. Johnston Jr. Jan 2018

Photofragment Imaging Fast Ion Beams, Michael D. Johnston Jr.

Doctoral Dissertations

Metal-containing ions have been the subject of much research due to their roles in catalytic activation and small cluster chemistries. However, they can be difficult to study both experimentally and theoretically, and new approaches are needed. The goal of the research described here is to characterize the electronic structures and thermodynamics of metal-containing ions using gas-phase spectroscopy experiments performed on a powerful new instrument. Presented in the following chapters are the details of a recently built velocity map imaging mass spectrometer that is capable of imaging the photofragments of trap-cooled (≥7K) ions produced in a versatile ion source. This instrument ...


3d Seismic Attribute Analysis And Machine Learning For Reservoir Characterization In Taranaki Basin, New Zealand, Aamer Alhakeem Jan 2018

3d Seismic Attribute Analysis And Machine Learning For Reservoir Characterization In Taranaki Basin, New Zealand, Aamer Alhakeem

Doctoral Dissertations

"The Kapuni group within the Taranaki Basin in New Zealand is a potential petroleum reservoir. The objective of the study includes building a sequential approach to identify different geological features and facies sequences within the strata, through visualizing the targeted formations by interpreting and correlating the regional geological data, 3D seismic, and well data by following a sequential workflow. First, seismic interpretation is performed targeting the Kapuni group formations, mainly, the Mangahewa C-sand and Kaimiro D-sand. Synthetic seismograms and well ties are conducted for structural maps, horizon slices, isopach, and velocity maps. Well log and morphological analyses are performed for ...


Paleogene-Early Neogene Palynomorphs From The Eastern Equatorial Atlantic And Southeastern Florida, Usa: Biostratigraphy And Paleoenvironmental Implications, Walaa K. Awad Jan 2018

Paleogene-Early Neogene Palynomorphs From The Eastern Equatorial Atlantic And Southeastern Florida, Usa: Biostratigraphy And Paleoenvironmental Implications, Walaa K. Awad

Doctoral Dissertations

"The transition from greenhouse conditions (Paleocene-Eocene Thermal Maximum, PETM) to icehouse conditions (Early Oligocene) is not well documented in tropical-subtropical regions. One hundred and five samples from Ocean Drilling Program (ODP) Site 959 (Hole 959A and Hole 959D) in the Cote d'Ivoire-Ghana Transform Margin, Alo-1 Well in the northern Niger Delta (Anambra) Basin, Nigeria, and W-17001 in southeastern Florida were studied for their palynological contents. Dinoflagellate cysts were mainly utilized for age refinement and to detect subtle changes in paleoenvironment and paleoclimate during the Paleocene-Early Eocene (ODP Hole 959D and Alo-1 Well) and Late Eocene-Early Miocene (ODP Hole 959A ...


Cox-Type Model Validation With Recurrent Event Data, Muna Mohamed Hammuda Jan 2018

Cox-Type Model Validation With Recurrent Event Data, Muna Mohamed Hammuda

Doctoral Dissertations

"Recurrent event data occurs in many disciplines such as actuarial science, biomedical studies, sociology, and environment to name a few. It is therefore important to develop models that describe the dynamic evolution of the event occurrences. One major problem of interest to researchers with these types of data is models for the distribution function of the time between events occurrences, especially in the presence of covariates that play a major role in having a better understanding of time to events.

This work pertains to statistical inference of the regression parameter and the baseline hazard function in a Cox-type model for ...


Disorder At First-Order Classical And Quantum Phase Transitions, Ahmed Khalil Ibrahim Jan 2018

Disorder At First-Order Classical And Quantum Phase Transitions, Ahmed Khalil Ibrahim

Doctoral Dissertations

"This dissertation studies the effects of quenched disorder on classical, quantum and nonequilibrium phase transitions. After a short introduction which covers the basic concepts of phase transitions, finite-size scaling and random disorder, the dissertation focuses on four separate but related projects. First, we investigate the influence of quenched disorder with long-range spatial correlations on the nonequilibrium phase transitions in the contact process. We show that the long-range correlations increase the probability to find rare atypical regions in the sample. This leads to enhanced Griffiths singularities and changes the universality class of the transition.

Project 2 and 3 focus on disorder ...


Fully Differential Study Of Dissociative Capture In P + H₂ Collisions, Basu Ram Lamichhane Jan 2018

Fully Differential Study Of Dissociative Capture In P + H₂ Collisions, Basu Ram Lamichhane

Doctoral Dissertations

"In recent years, the key role of the projectile coherence properties has been studied in several ion-atom scattering processes. These studies strongly suggested that cross sections could be significantly affected by the projectile coherence properties, especially for fast, heavy ions. In the present study, we used such coherence effects as a tool to sensitively analyze the few- body dynamics of the scattering process. To this end, we performed three kinematically complete experiments on fragmentation of H2 by 75 keV proton impacts. A novel approach was used to analyze coherence and interference effects in the observed cross-sections. The idea was ...


On Modeling Quantities For Insurer Solvency Against Catastrophe Under Some Markovian Assumptions, Daniel Jefferson Geiger Jan 2018

On Modeling Quantities For Insurer Solvency Against Catastrophe Under Some Markovian Assumptions, Daniel Jefferson Geiger

Doctoral Dissertations

"Insurance companies sometimes face catastrophic losses, yet they must remain solvent enough to meet the legal obligation of covering all claims. Catastrophes can result in large damages to the policyholders, causing the arrival of numerous claims to insurance companies at once. Furthermore, the severity of an event could impact the time until the next occurrence. An insurer needs certain levels of startup capital to meet all claims, and then must have adequate reserves on a continual basis, even more so when catastrophes occur. This work examines two facets of these matters: for an infinite time horizon, we extend and develop ...


Mitigation Of Environmental Hazards Of Sulfide Mineral Flotation With An Insight Into Froth Stability And Flotation Performance, Muhammad Badar Hayat Jan 2018

Mitigation Of Environmental Hazards Of Sulfide Mineral Flotation With An Insight Into Froth Stability And Flotation Performance, Muhammad Badar Hayat

Doctoral Dissertations

"Today's major challenges facing the flotation of sulfide minerals involve constant variability in the ore composition; environmental concerns; water scarcity and inefficient plant performance. The present work addresses these challenges faced by the flotation process of complex sulfide ore of Mississippi Valley type with an insight into the froth stability and the flotation performance. The first project in this study was aimed at finding the optimum conditions for the bulk flotation of galena (PbS) and chalcopyrite (CuFeS₂) through Response Surface Methodology (RSM). In the second project, an attempt was made to replace toxic sodium cyanide (NaCN) with the biodegradable ...


Electrodeposited Semiconductor Nanostructures & Epitaxial Thin Films For Flexible Electronics, Naveen Kumar Mahenderkar Jan 2018

Electrodeposited Semiconductor Nanostructures & Epitaxial Thin Films For Flexible Electronics, Naveen Kumar Mahenderkar

Doctoral Dissertations

"Single-crystal Si is the bedrock of semiconductor devices due to the high crystalline perfection which minimizes electron-hole recombination, and the dense native silicon oxide which minimizes surface states. To expand the palette of electronic materials beyond planar Si, an inexpensive source of highly ordered material is needed that can serve as an inert substrate for the epitaxial growth of grain boundary-free semiconductors, photonic materials, and superconductors. There is also a need for a simple, inexpensive, and scalable fabrication technique for the growth of semiconductor nanostructures and thin films. This dissertation focuses on the fabrication of semiconducting nanowires (polycrystalline Ge & epitaxial ...


Aerogels For Energy Storage Applications: From Shape Memory Materials To Thermites And Explosives, Suraj Donthula Jan 2018

Aerogels For Energy Storage Applications: From Shape Memory Materials To Thermites And Explosives, Suraj Donthula

Doctoral Dissertations

"Aerogels are three dimensional highly porous solid objects that provide density reduction compared to dense objects. Those materials can have applications in different classes of energy storage and the two types that are focused in this dissertation are mechanical energy and thermal energy storage. Shape memory materials can store and recover elastic deformation energy when triggered by an external stimulus such as temperature. To incorporate those properties, shape memory polymeric aerogels (SMPA) were synthesized from a rigid isocyanurate containing triisocyanate (N3300 A) and four short oligomeric derivatives of ethylene glycol: H(OCH2CH2)nOH (1 ≤ n ≤ 4 ...


Machine Learning Techniques Implementation In Power Optimization, Data Processing, And Bio-Medical Applications, Khalid Khairullah Mezied Al-Jabery Jan 2018

Machine Learning Techniques Implementation In Power Optimization, Data Processing, And Bio-Medical Applications, Khalid Khairullah Mezied Al-Jabery

Doctoral Dissertations

"The rapid progress and development in machine-learning algorithms becomes a key factor in determining the future of humanity. These algorithms and techniques were utilized to solve a wide spectrum of problems extended from data mining and knowledge discovery to unsupervised learning and optimization. This dissertation consists of two study areas. The first area investigates the use of reinforcement learning and adaptive critic design algorithms in the field of power grid control. The second area in this dissertation, consisting of three papers, focuses on developing and applying clustering algorithms on biomedical data. The first paper presents a novel modelling approach for ...


Search For Long-Lived, Massive Particles Decaying Into Dimuon Vertices In Pp Collisions At 13 Tev With The Atlas Detector At The Lhc, Nathan Bernard Jan 2018

Search For Long-Lived, Massive Particles Decaying Into Dimuon Vertices In Pp Collisions At 13 Tev With The Atlas Detector At The Lhc, Nathan Bernard

Doctoral Dissertations

A search for long-lived, massive particles decaying into dimuon pairs, in 32.9 fb-1 of data analyzed from the ATLAS detector is presented. Two signal models are considered: GGM SUSY, where the long lived particle mass is between 300-1000 GeV, and the dark photon model, where the ZD mass is between 20-60 GeV. An excess over the predicted background is observed in the GGM channel, however the angular/kinematic distributions of the excess vertices are consistent with a detec- tor/conditions related issue. A modified selection is used for the GGM channel which increases the signal sensitivity. 95 ...


A Study Of High Performance Multiple Precision Arithmetic On Graphics Processing Units, Niall Emmart Jan 2018

A Study Of High Performance Multiple Precision Arithmetic On Graphics Processing Units, Niall Emmart

Doctoral Dissertations

Multiple precision (MP) arithmetic is a core building block of a wide variety of algorithms in computational mathematics and computer science. In mathematics MP is used in computational number theory, geometric computation, experimental mathematics, and in some random matrix problems. In computer science, MP arithmetic is primarily used in cryptographic algorithms: securing communications, digital signatures, and code breaking. In most of these application areas, the factor that limits performance is the MP arithmetic. The focus of our research is to build and analyze highly optimized libraries that allow the MP operations to be offloaded from the CPU to the GPU ...


On The Performance Of Adaptive Bitrate Streaming And Parallel Cloud Applications, Cong Wang Jan 2018

On The Performance Of Adaptive Bitrate Streaming And Parallel Cloud Applications, Cong Wang

Doctoral Dissertations

As shown in recent studies, video streaming is by far the biggest category of backbone Internet traffic in the US. As a measure to reduce the cost of highly over-provisioned physical infrastructures while remaining the quality of video services, many streaming service providers started to use cloud services, where physical resources can be dynamically allocated based on current demand.

In this dissertation, we seek to evaluate and improve the performance for both Adaptive Bitrate (ABR) video streaming and cloud applications. First, we present a set of measurement studies for ABR streaming applications. Using the data from the application, network, and ...


Vibrated Squares As Equilibrium And Active Matter, Lee Askew Walsh Jan 2018

Vibrated Squares As Equilibrium And Active Matter, Lee Askew Walsh

Doctoral Dissertations

We study the effects of particle shape and self-propulsion on the collective behaviors of a two-dimensional granular fluid, using an experimental system of hard square grains. We energize the system by vibration, which, depending on particle shape, induces either isotropic diffusion or persistent self-propulsion in the particles. We use specially designed grains as a model system to study (i) the equilibrium packing of hard squares in two dimensions, (ii) the dynamics of athermal self-propelled particles, and (iii) the melting kinetics of an unconfined granular crystallite.

The first study concerns the phase diagram of a two-dimensional fluid of hard squares, which ...


Eccentricity Modulation Of Precessional Variation In The Earth’S Climate Response To Astronomical Forcing: A Solution To The 41-Kyr Mystery, Rajarshi Roychowdhury Jan 2018

Eccentricity Modulation Of Precessional Variation In The Earth’S Climate Response To Astronomical Forcing: A Solution To The 41-Kyr Mystery, Rajarshi Roychowdhury

Doctoral Dissertations

The 41,000-year variability of Earth’s glacial cycles during the late Pliocene-early Pleistocene is usually attributed to variations in Earth’s obliquity (axial tilt). However, a satisfactory explanation for the lack of precessional variation in marine d18O records, a proxy for ocean temperature and ice-volume, remains contested. Here, a physically based climate model is used to show that the climatic effect of precession is muted in global isotope records due to two different mechanisms, with each dominating as a function of eccentricity. At low eccentricities (e0.019), the time-integrated summer insolation and number of positive degree-days impacting ...


The Molecular Basis Of Caspase-9 Inactivation By Pka And C-Abl Kinases, Banyuhay Paningbatan Serrano Jan 2018

The Molecular Basis Of Caspase-9 Inactivation By Pka And C-Abl Kinases, Banyuhay Paningbatan Serrano

Doctoral Dissertations

Caspases are the cysteine proteases that facilitate the fundamental pathway of programmed cell death or apoptosis. The activation and function of these powerful enzymes are tightly regulated to ensure the faithful execution of apoptosis and prevent untimely cell death. Many deadly human diseases such as cancer, neurodegeneration and autoimmune disorders have been associated with defective activation and faulty regulation of caspases. As such, caspases are considered as attractive drug targets, which when properly controlled, can lead to effective therapeutics for apoptosis-related diseases. Thus, comprehensive investigations of the structure, function and regulation of caspases are necessary to understand the complex mechanisms ...


Effects Of Floral Phytochemicals On Growth And Evolution Of A Parasite Of Bumble Bees, Evan Palmer-Young Jan 2018

Effects Of Floral Phytochemicals On Growth And Evolution Of A Parasite Of Bumble Bees, Evan Palmer-Young

Doctoral Dissertations

Background: Nectar and pollen are rich in phytochemicals, some of which can reduce disease in pollinators, including agriculturally important honey and bumble bees. Floral phytochemicals could influence the ecological and evolutionary relationships between plants, their pollinators, and parasites that cause pollinator disease. Antiparasitic effects of phytochemicals could be exploited to ameliorate pollinator disease and decline, and thereby sustain pollinator-dependent agricultural production. However, prior studies showed variable effects of phytochemicals on infection in live bees, where differences in bee genotype, abiotic conditions, and parasite strain could influence results.

Approach: I used cell cultures of the intestinal trypanosome parasite of bumble bees ...


Polymeric Peptide Mimics For Protein Delivery, Coralie Backlund Jan 2018

Polymeric Peptide Mimics For Protein Delivery, Coralie Backlund

Doctoral Dissertations

The plasma membrane is a major obstacle in the development and use of biomacromolecules for intracellular applications. Consequently, proteins with intracellular targets represent an enormous, yet under studied avenue for therapeutics. Extended research has aimed at facilitating intracellular delivery of exogenous proteins using protein transduction domains (PTDs), which allow transport of bioactive molecules into cells. Synthetic polymers, inspired by PTDs, provide a well-controlled platform to vary molecular architecture for structure activity relationship studies. Specifically, this thesis focuses on the use of ring-opening metathesis, a facile and efficient polymerization technique, through which we can vary structural parameters to optimize delivery of ...


Transfer Learning With Mixtures Of Manifolds, Thomas Boucher Jan 2018

Transfer Learning With Mixtures Of Manifolds, Thomas Boucher

Doctoral Dissertations

Advances in scientific instrumentation technology have increased the speed of data acquisition and the precision of sampling, creating an abundance of high-dimensional data sets. The ability to combine these disparate data sets and to transfer information between them is critical to accurate scientific analysis. Many modern-day instruments can record data at many thousands of channels, far greater than the actual degrees of freedom in the sample data. This makes manifold learning, a class of methods that exploit the observation that high-dimensional data tend to lie on lower-dimensional manifolds, especially well-suited to this transfer learning task.

Existing manifold-based transfer learning methods ...


Emergent Phenomena In Quantum Critical Systems, Kun Chen Jan 2018

Emergent Phenomena In Quantum Critical Systems, Kun Chen

Doctoral Dissertations

A quantum critical point (QCP) is a point in the phase diagram of quantum matter where a continuous phase transition takes place at zero temperature. Low-dimensional quantum critical systems are strongly correlated, therefore hosting nontrivial emergent phenomena. In this thesis, we first address two decades-old problems on quantum critical dynamics. We then reveal two novel emergent phenomena of quantum critical impurity problems. In the first part of the thesis, we address the linear response dynamics of the $(2+1)$-dimensional $O(2)$ quantum critical universality class, which can be realized in the ultracold bosonic system near the superfluid (SF) to ...