Digital Commons Network^™

Finite Semifields And Their Applications, Shamsa Ali Rashed Al Saedi

Theses

This thesis is concerned with finite semi fields. The objective of this thesis is to give a full description of Knuth orbits of known commutative semi fields. We also describe planar functions corresponding to commutative semi fields. Results are presented by tables. Nuclei of semi fields are studied. Finally we consider applications of semi fields, planar functions and spreads to construction of mutually unbiased bases.

Learning Robust And Discriminative Manifold Representations For Pattern Recognition, Sriram Kumar

Theses

Face and object recognition find applications in domains such as biometrics, surveillance and human computer interaction. An important component in any recognition pipeline is to learn pertinent image representations that will help the system to discriminate one image class from another. These representations enable the system to learn a discriminative function that can classify a wide range of images. In practical situations, the images acquired are often corrupted with occlusions and noise. Thus, a robust and discriminative learning is necessary for good classification performance.

This thesis explores two scenarios where robust and discriminative manifold representations help recognize face and object …

Binary Metal Oxides Based On Fe (Iii) And Ti (Iv) As Efficient Catalysts For Total Oxidation Of Volatile Organic Compound Pollutants, Said Abdullah Sulaiman Almamari

Theses

Fe (III)-modified Titania and Fe (III)-Ti (IV) binary oxides have received much less attention as possible catalysts compared to their parent single-metal oxides, Fe₂O₃ and TiO₂. This could be due to the difficulty of obtaining pure desired monophases. In addition, the effect of different preparative conditions on the textural properties of sol-gel-prepared Ti-Fe mixed oxides was rarely studied. Furthermore, the effect of the composition on the reducibility and the catalytic activity of these composites was never studied. In the present work, Ti-Fe mixed oxides were prepared using a modified sol-gel method and their textural properties …

Securing The Integrity Of The Power Distribution System For Smart Grid Applications, Hosam Yousef Hittini

Theses

The distribution system is one of the main components in a smart grid, readings are transferred from the distribution substations to the control center. Compromising transferred system data will result in drawing wrong conclusions about current operation status at the control center. Which leads to sending wrong operational commands that may result in very serious consequences.

Firstly, we propose a scalable communications architecture for future smart grid distribution systems (i.e. Security Aware Distribution System Architecture - SADSA). The architecture is adaptable to use Wi-Fi or other technologies to transfer smart grid information. The architecture is studied from various angles. Both …

Determination Of Multiple Pesticides Residues In Imported Tea In Uae Using Liquid And Gas Chromatography And Tandem Mass Spectrometry, Sarra Ali Mohammed Hassan Almulla

Theses

An accurate, rapid and reliable method for the simultaneous determination of 48 pesticide residues in United Arab Emirates imported tea (Green and Black) by liquid and gas chromatography coupled with tandem mass spectrometry LC–ESI (+) - MS/MS and GC-EI-MS/MS. Multiple reaction monitoring (MRM) mode was used in which two transitions for each compound for pesticide identification and quantification in the presence of internal standards. Modified quick, easy, cheap, effective, rugged, safe (QuEChERS) method was used for sample clean up and preparation for chromatographic analysis. The performance of the newly developed analytical method was validated in accordance with EU SANCO guidelines …

Numerical Analysis For The Hemodynamics In Unruptured Cerebral Aneurysms, Hashem Mhd Hicham Alargha

Theses

A cerebral aneurysm is a vascular disorder characterized by abnormal focal dilation of a brain artery which is considered as a serious and potentially life-threatening condition. Cerebral aneurysms affect around 2%-5% of adults and they are fatal and can rupture with an overall mortality rate of more than 50%. Through computational fluid dynamics investigation, this study is offering a closer look into the initiation growth and rupture of cerebral aneurysms. Four focus points are studied in this thesis which are sensitivity analysis of blood viscosity in aneurysms, the effect of cerebral aneurysm size on wall stresses and strain, hazard effects …

Achievable Accuracy Of Radiation Dose Measurement For Linear Accelerators Using Different Protocols, Mariam Hamad Al Darmaki

Theses

The aim of radiotherapy treatment is to deliver a specified radiation dose throughout a definite target volume within predetermined levels of accuracy and homogeneity; at the same time ensuring adequate dose sparing of surrounding normal tissue. Radiotherapy is a complex process involving a number of steps and the accuracy of each stage has a direct impact on the treatment outcome. At each stage, comprehensive quality assurance procedures are required to ensure safe and accurate delivery of the prescribed dose.

This project will aim to determine the currently achievable accuracy and reproducibility of radiotherapy dosimetry and assess the current recommendations for …

Thermal Analysis For The Purpose Of Fault Diagnosis Of Commercial Proton Exchange Membrane Fuel Cells (Pemfc), Reem Izzeldin Elsadig Salim

Theses

The world's awareness towards the amount of destruction that our extensive and ignorant lifestyles in the past few decades have imposed on the environment is growing day after day. This resulted in an increased governmental and research interest towards the development and use of green technology. Fuel Cells are one of the green technologies that received a major share of research interest in the past decade.

However, despite their promising features, Fuel Cell systems still lack a solid fault diagnosis and predictive maintenance study. There are numerous faults that have to be detected and diagnosed on a fuel cell power …

Some Algebraic Aspect And Applications Of A Family Of Functions Over Finite Fields, Shaima Ahmed Thabet

Theses

We study two families of functions over finite fields; the Multivalued Threshold

Functions and the Multivariate Polynomials. Recent advances made in our Conception and our understanding of Boolean Threshold Functions and Multivariate Threshold Functions have considerably increased the importance of the role that they Play in our days in areas like cryptography, circuit complexity, learning theory, social choice, quantum complexity, and in many other areas. Theoretical aspects of Bovid and Gauche who gave an algebraic first studied threshold functions Approach of Boolean Threshold Functions using group ring theory. We will present some algebraic properties of Boolean threshold functions. For the …

Study Of The Seasonal And Interannual Variability Of Phytoplankton Bloom In Arabian Gulf Using Modisdata, Malik Mutasim Malik Gasim

Theses

The Arabian Gulf is a semi enclosed large water body that experiences seasonal

variations and reversal of it water currents flow circulation. The Gulf waters are characterized by having high primary productivity and strong phytoplankton blooms at particular seasons within the year. Phytoplankton is a base of the food chain for marine species, providing an essential food resource for aquatic life. Marine phytoplankton affects the diversity of any marine ecosystem and drives its functioning and is strongly correlated with fishery yields. The primary

objectives of this research study are to answer key research questions related to phytoplankton blooms in the …

Biometrics-Based Dynamic Authentication For Secure Services, Saif Mohammed Saeed Abdulla Al Aryani

Theses

This thesis proposes a secure authentication protocol against physical session hijacking attacks. In client/server technology, users establish sessions to access the services offered by the servers. However, using physical session hijacking attacks, malicious users may physically take control of ongoing sessions. Malicious users also can establish sessions with servers using stolen passwords. In both cases, the server will be communicating with the wrong user who pretends to be the real user. The goal of this authentication protocol is to continuously and dynamically ensure that during an ongoing session the current session’s user is himself the real person that is known …

Killing Two Birds With One Stone: The Concurrent Development Of The Novel Alignment Free Tree Building Method, Scrawkov-Phy, And The Extensible Phyloinformatics Utility, Emu-Phy., J. Nick Fisk

Theses

Many components of phylogenetic inference belong to the most computationally challenging and complex domain of problems. To further escalate the challenge, the genomics revolution has exponentially increased the amount of data available for analysis. This, combined with the foundational nature of phylogenetic analysis, has prompted the development of novel methods for managing and analyzing phylogenomic data, as well as improving or intelligently utilizing current ones. In this study, a novel alignment tree building algorithm using Quasi-Hidden Markov Models (QHMMs), Scrawkov-Phy, is introduced. Additionally, exploratory work in the design and implementation of an extensible phyloinformatics tool, EMU-Phy, is described. Lastly, features …

Spirituality & Young Adults Work Performance, Kirstijan Hrdzic

Theses

Young adults are facing though time adapting to their workplace environment. This results with reduced work performance. In order to find intrinsic motivation for their work, practicing spirituality is one of the possible solutions. The purpose of this study was to investigate the relationship between spirituality and young adults’ work performance. A survey was administered online asking young working adults in the Zagreb area to complete a 37 items questionnaire. The first part of questionnaire contained items that tested perceived daily spirituality experience, while the second part of questionnaire contained items pertaining to task work performance, contextual work performance and …

Clearance Analysis Of 3d Printed Assemblies Using Fused Filament Extrusion, Kshitij Luthria

Theses

3D Printing technologies have been around for the better part of 30 years now, and researchers today have a reasonably good understanding of how the different processes work. A focus for the next era of 3D printing will likely be to gain a deeper understanding of how these processes can be used in unique applications. One such unique application that can potentially change the way conventional manufacturing works involves 3D printing of assemblies. By printing assemblies ‘in-situ’, multiple assembly steps can be by-passed, thus increasing efficiency and decreasing costs. This research specifically seeks to develop an understanding of how clearances …

Dynamics And Power Generation Potential From A Tethered Kite Moving In A Horizontal Flightpath, Glenn Romo Gavi

Theses

Tethered-wing power systems are a viable possibility for collecting energy from stronger, more consistent winds found in the upper regions of the atmosphere where conventional wind turbines are incapable of reaching. To date, all of the tethered-wing systems fly with the tether oriented down-wind of the ground attachment point. Examined here are the dynamics and performance of a novel system where the tether is oriented both upwind and downwind of the ground attachment point during normal operation of the device. Certain prototypes built by Makani and Ampyx Power are considered to have motions analogous to the motions of the blade …

An Artificial Neural Networks Based Temperature Prediction Framework For Network-On-Chip Based Multicore Platform, Sandeep Aswath Narayana

Theses

Continuous improvement in silicon process technologies has made possible the integration of hundreds of cores on a single chip. However, power and heat have become dominant constraints in designing these massive multicore chips causing issues with reliability, timing variations and reduced lifetime of the chips. Dynamic Thermal Management (DTM) is a solution to avoid high temperatures on the die. Typical DTM schemes only address core level thermal issues. However, the Network-on-chip (NoC) paradigm, which has emerged as an enabling methodology for integrating hundreds to thousands of cores on the same die can contribute significantly to the thermal issues. Moreover, the …

Shape Representation Using The Helmholtz Equation, Laura A. Rolston

Theses

Image classification uses a learning procedure to predict class labels based on quantitative characteristics of an image. Typical approaches involve first extracting features from a set of labeled images and using a subset of those images and their features as a "training set" to train a classifier. The classifier is then applied to the test images to predict their labels. In this thesis, we focus on shape classification and propose new features to be used for classifying binary images. Specifically, we propose new features based on the hitting time distribution of a Brownian motion process defined on the shape.

It …

Opto-Mechanical Design Of Synchrotron Radiation-Based Far-Infrared Spectroscopic Ellipsometer With Strong Magnetic-Field, Ahmad Abbas Chaudhry

Theses

The objective of this dissertation is to present opto-mechanical design of a synchrotron radiation based far-infrared spectroscopic ellipsometer with a strong external magnetic-field capability. Since high magnetic field has enabled major breakthrough in science such instrument will be highly important to the field of condensed matter physics and characterization of advanced electronic materials. This instrument will be installed at the multi-User facility with the most advanced synchrotron light source: Natonal Synchrotron Source (NSLS-II) at Brookhaven National Laboratory (BNL).The proposed here instrument is capable to measure full Mueller matrix spectroscopic ellipsometry spectra in high magnetic fields of up to 9 Tesla. …

Effects Of Human Development On Aeolian Sediment Transport Rates Within An Adjacent Undeveloped Backshore Enclave, Kayla L. Kaplan

Theses

Sandy backshore enclaves are created where shorefront buildings are lost during high magnitude storms. Subsequent foredune growth in these enclaves is critical to providing protection to landward development. Conditions for foredune growth and sediment flux within an enclave can be influenced by the presence of adjacent buildings. The objectives of this research are to assess the following questions: what is the nature of sediment flux on a beach within an enclave, what are the potential constraints to transport on a beach within an enclave and, are natural processes alone able to sustain a foredune in an enclave. A field investigation …

Computational And Experimental Determination Of The Hydrodynamics In A Stirred Unbaffled Vessel Provided With Angle-Mounted Axial Impellers, Ji Ma

Theses

In most industrial applications, stirred tanks and reactors are typically provided with baffles to improve their mixing characteristics. However, in a number of pharmaceutical production facilities unbaffled vessels are commonly used. The absence of baffles is preferred in such cases because it reduces the potential for contamination and makes cleaning the vessel between batches easier. However, the lack of baffles also has a negative impact on the system’s hydrodynamics since it often results in poor mixing of the batch, especially if the impeller is centrally placed, since the liquid in such a system is subject to a strong tangential flow, …

A Study Of Kinematics And Kinetics In Time-Constrained Arm Movements, Oyindamola Owoeye

Theses

Several studies such as the equilibrium point hypothesis (EPH) purport that the motor signals that descend from the brain instead of encoding muscle torques, influence an existing relationship between muscle torque and body configuration.

In the present study, the possibility of torque depending explicitly on position was tested using a task in which subjects (N=5) moved a simulated weightless frictionless mass through a small (<8 degree) elbow extension in order to move a cursor on a screen to a target location. Each subject completed 720 trials. On ~10% of trials the simulated mass was increased unknown to the subject. The relationship between the cursor’s position and the torque applied to the system was held constant even when the simulated mass was increased. Thus, any change in torque produced was neither due the subjects’ perception of the mass nor due to their perception of the cursor. The time at which the subjects torque changed direction was seen to be significantly different (p<0.005) during trials which the mass changed. This change in torque is concluded to be position-dependent. However the possibility of this being a merely mechanical effect could not be ruled out by due to poor EMG collection.

A post-hoc analysis of different position-dependent motor control models, was done. Particularly, an exponential spring model, a linear spring model, and a linear spring with relative damping model were each tested to see how well …

Triplex Dna Receptor-Gold Nanoparticle Conjugates For Detection Of Oxidized Dna Base, Qingyu Xing

Theses

Oxidations of DNA nucleobases are believed to be one of the sources of aging and some age-dependent disease, such as cancer. Human body have various mechanisms to repair damaged DNA and base-excision-repair is one mechanism for removing those oxidized nucleobases. This mechanism processes in the cells by cutting the oxidized nucleobases from deoxyribose and letting them excrete though urine. Detection of those abnormal nucleobases in urine has been suggested as a convenient way of early cancer diagnosis. 5-OHU (5-hydroxyuracil), the oxidation product of cytosine, is one of those abnormal nucleobases and it potentially forms base pairs with all four DNA …

Realization Of Dynamixel Servo Plant Parameters To Improve Admittance Control For A Compliant Human-Robot Interaction, Ahmad Zahid Rao

Theses

In theory, admittance control offers a very effective method of implementing smooth human-robot interaction. It allows the user’s applied force to control the movement of a powerful robot as if the robot were a small, passive mass. However, the real-world application of admittance control faces limitation posed by the dynamics of servo motors, the accuracy of the force sensors, and the computation speed of processors.

This research investigates the limitations on achieving compliant passive behavior when using state-of-the-art actuators, sensors and processors. The work involves characterizing the dynamic behavior of the servo motors, development of improved differential equations representing admittance …

Comparison Of Muscle Synergies Elicited From Transcranial Meganetic Stimulation (Tms) And Voluntary Movements, Yifei Wei

Theses

A key question in motor control is the redundancy of musculoskeletal elements involved. This problem refers to as the degree of freedom problem. The Muscle Synergy Hypothesis is one of the hypotheses that aim to resolve the problem which defines that a muscle synergy is a combination of a small set of muscles activated at different levels, serving as a building block that constructs motor behaviors. A recent study (Overduin et al. 2012) demonstrated that muscle synergies decomposed by Nonnegative Matrix Factorization (NMF) from EMG patterns evoked by intra-cortical microsimulation (ICMS) in the monkey remarkably matched ones observed in naturalistic …

Iterative Methods For Stochastic Variational Inequalities, Xiangnan Zhang

Theses

In this work, we consider stochastic variational inequalities arising from a certain class of equilibrium problems with uncertainties. Uncertainties in the models are introduced through data that are known through their probabilistic distributions. We consider several extragradient methods for the solutions of the variational inequalities and compare their relative efficiency and eectiveness through thorough numerical comparisons. Several applications such as trac equilibrium, environmental games, and oligopolistic market equilibrium are considered.

Online Novelty Detection System: One-Class Classification Of Systemic Operation, Ryan M. Bowen

Theses

Presented is an Online Novelty Detection System (ONDS) that uses Gaussian Mixture Models (GMMs) and one-class classification techniques to identify novel information from multivariate times-series data. Multiple data preprocessing methods are explored and features vectors formed from frequency components obtained by the Fast Fourier Transform (FFT) and Welch's method of estimating Power Spectral Density (PSD). The number of features are reduced by using bandpower schemes and Principal Component Analysis (PCA). The Expectation Maximization (EM) algorithm is used to learn parameters for GMMs on feature vectors collected from only normal operational conditions. One-class classification is achieved by thresholding likelihood values relative …

Respecting Anatomically Rigid Regions In Nonrigid Registration, Eric J. Spangler

Theses

Medical image registration has received considerable attention in the medical imaging and computer vision communities because of the variety of ways in which it can potentially improve patient care. This application of image registration aligns images of regions of the human body for comparing images of the same patient at different times, for example, when assessing differences in a disease over time; comparing images of the same anatomical structure across different patients, for example, to understand patient variability; and comparing images of the same patient from different modalities that provide complementary information, for example, CT and PET to assess cancer. …

Geochemical Investigation Of Anomalous Arsenic Enrichment In The Santiago Peak Volcanics Of Southern California, Elizabeth C. Johnston

Theses

Arsenic (As) is enriched in the Santiago Peak Volcanics (SPV) that crop out at Black Mountain Open Space Park in San Diego, CA. Thus, the Black Mountain SPV present an excellent opportunity to investigate As enrichment in ancient volcanic arc systems as a result of deep earth subduction zone processes. Through targeted field study of this unit, we aim to (1) confirm the volcanic arc provenance of rocks cropping out at Black Mountain, (2) investigate As enrichment in relation to volcanic arc processes, and (3) propose a model for As occurrence in the SPV. Our findings indicate Black Mountain SPV …

Real-Time Characterisation Of Dynamic Laser Fields, Thomas Butler

Theses

Many modern technologies rely on laser devices, in areas such as communications, sensing, and imaging. Examination and research into the fundamental operational dynamics of lasers, and characterisation of laser performance, are a crucial tool in ensuring the quality and effectiveness of laser-based applications. The development of characterisation tools is an important part of improving upon existing technologies and advancing the next generation of devices.

In this work, a real-time multiheterodyne detection technique is developed which allows for the study of dynamically varying pulse trains formed by optical frequency combs.

Secure Storage Via Information Dispersal Across Network Overlays, Reece G. Johnston

Theses

In this paper, we describe a secure distributed storage model to be used especially with untrusted devices, most notably cloud storage devices. The model does so through a peer-to-peer overlay and storage protocol designed to run on existing networked systems. We utilize a structured overlay that is organized in a layered, hierarchical manner based on the underlying network structure. These layers are used as storage sites for pieces of data near the layer at which that data is needed. This data is generated and distributed via a technique called an information dispersal algorithm (IDA) which utilizes an erasure code such …