Digital Commons Network^™

Designing Better Symbols: An Attentional Approach To Match Symbols To Performance Goals, Hannah North

Dissertations, Master's Theses and Master's Reports

Effective displays require symbol sets that are customized to specific tasks and performance goals. In order to create such sets, designers must account for the effects of top-down and bottom-up attention. The current work presents a pair of experiments that examined the effects of salience and cueing in a change detection tasks within the flicker paradigm (Rensink, O’Regan and Clark, 1997). Each trial, participants either received no cue or a cue indicating which symbol would be the target. This cueing manipulation isolated top-down effects to the cued condition. Consistent with previous studies (Orchard, 2012; Steelman, Orchard, Fletcher, Cockshell, Williamson & …

Cave Detection Using Seismic Methods At Madison Blue Spring State Park, Madison County, Florida, Charles Breithaupt

Dissertations, Master's Theses and Master's Reports

Locating caves and quantifying their geometries has significant importance in aquifer characterization, sinkhole mitigation, and contaminant transport monitoring. Several geophysical methods have been used for cave detection with limited success, but no reliable solution has been found. New developments in seismic techniques, however, show promising results indicating that cave voids may be more accurately detected.

We evaluated the capability of several seismic techniques to detect caves by collecting new seismic data over a known conduit connected to Madison Blue Spring, in northern Florida. These analyses validated the abilities of diffracted surface waves to detect water-filled caves by viewing these data …

Comparisons Of Seismic Interferometry By Cross Correlation, Deconvolution, And Cross Coherence, Haitao Cao

Dissertations, Master's Theses and Master's Reports

Ambient noise seismic interferometry (ANSI) has been applied widely for geophysical investigations including earthquake tomography, civil engineering and seismic exploration purposes. Comparing this approach with the traditional active seismic survey, the application of ANSI is cost effective, environmentally friendly and easily repeatable. Conventional seismic interferometry by cross correlating wavefields recorded at different receivers has already obtained fruitful results.

Even though the application of seismic interferometry (SI) by cross correlation has been successful, different methods for the processing workflow such as cross coherence and deconvolution have been conducted in an effort to improve the resolution. While these three methods have been …

Vegetation Dynamics And Nitrogen Cycling Responses To Simulated Emerald Ash Borer Infestation In Fraxinus Nigra-Dominated Wetlands Of Upper Michigan, Usa, Joshua Davis

Dissertations, Master's Theses and Master's Reports

Throughout many North American forests, the invasive emerald ash borer (EAB, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)) is a significant threat to biodiversity and ecosystem processes. The fate of Fraxinus nigra Marshall (black ash) is of particular concern, as it is frequently a dominant canopy species across much of its range. A multiyear manipulative study was conducted to investigate the potential impacts of EAB on vegetation dynamics and nitrogen (N) cycling in nine F. nigra-dominated wetlands of Upper Michigan, USA. The effects of early- and late-stage infestations were simulated by girdling (‘Girdle’) or felling (‘Ash-Cut’) all ash stems greater than …

Defect-Deferred Correction Method For The Two-Domain Convection-Dominated Convection-Diffusion Problem, Dilek Erkmen

Dissertations, Master's Theses and Master's Reports

We present a method for solving a fluid-fluid interaction problem (two convection-dominated convection-diusion problems adjoined by an interface), which is a simplifed version of the atmosphere ocean coupling problem. The method resolves some of the issues that can be crucial to the fluid-fluid interaction problems: it is a partitioned time stepping method, yet it is of high order accuracy in both space and time (the two-step algorithm considered in this report provides second order accuracy); it allows for the usage of the legacy codes (which is a common requirement when resolving flows in complex geometries), yet it can be applied …

Enhancement Of Margrave Deconvolution And Q Estimation In Highly Attenuating Media Using The Modified S-Transform, Adnan Djeffal

Dissertations, Master's Theses and Master's Reports

We evaluate the performance of the Margrave deconvolution and spectral ratio methods using the Gabor, S-, and modified S transforms in highly attenuating media, where the quality factor changes with depth dramatically. Our results substantiate that the modified S-transform deconvolution is more robust in terms of generating fewer artifacts and providing better estimates of reflectivities than the Gabor transform. The results also show that using the modified S-transform in the spectral ratio method produces better Q estimates than the S-transform and the Fourier transform that is conventionally used in the spectral ratio method. This improvement in the estimates of reflectivities …

A Novel Low Latency, High Resolution And Low Cost Time Synchronization, Ali Aghdaei

Dissertations, Master's Theses and Master's Reports

This report presents a new low latency, high resolution and low cost timing synchro- nization technique for digital receivers. Traditional timing synchronization employs Matched filter to perform cross-correlation operation and estimate Time-of-Arrival (TOA) of the signal. Decreasing the latency of the traditional method through over- sampling leads to a higher complexity and it is not viable. Furthermore, to obtain a high-resolution TOA, an extensive bandwidth is required, which results in high system complexity. The proposed method uses single bit quantization to employ XNOR blocks instead of multiplier and accumulator (MAC) blocks in the traditional method. This substantially decreases complexity incorporating …

The Effect Of Solidification Rate And Solutionizing Quench Rate On The Mechanical Properties And Hardening Response Of Aluminum Alloys: A Quantitative Comparison, Rafael Gil-Figueroa

Dissertations, Master's Theses and Master's Reports

A comparative study of five aluminum alloys was performed to characterize the effect of solidification rate and quench rate on casting microstructure and properties. The alloys were cast in the geometry for Jominy End Quench (JEQ) testing, so as to take advantage of the JEQ test’s ability to give data on multiple quench rates in a single sample and illustrate the quench sensitivity of an alloy. While the Jominy End Quench test has been used in aluminum alloys, the effects of solidification rates have not been assessed in depth. The work done by other studies has either focused on a …

Can Seismic Velocity Stacking Errors Result In The Low-Frequency Shadow?, Umit Serhan Inan

Dissertations, Master's Theses and Master's Reports

The low-frequency shadow is the area on reflection seismic data, underneath gas reservoirs, that exhibits anomalously low frequency. This phenomenon has been related to the highly attenuating nature of the gas reservoir, which could explain the low-frequency shadows observed underneath extremely thick reservoirs, but not the ones underneath thin reservoirs. There are several other mechanisms that could be responsible, however detailed analysis of these possible explanations is yet to be found in the literature.

The main focus of this research is to test the possible contribution of stacking of offset seismic data, namely, their mis-stacking, to the generation of the …

The Integration Of Mobile Technology To Lower The Risk Of Developing Cervical Cancer In Hiv Positive Women, Tugce Kinik

Dissertations, Master's Theses and Master's Reports

Cervical cancer is the most common cancer in HIV positive women in the world [1]. According to epidemiologists, HPV infection alone will not initiate cervical cancer [2]. In addition to high risk HPV types, smoking, long term hormonal contraceptive use, high parity, HIV/AIDS infection, sexual activity before 20 years of age, multiple sexual partners, exposure to sexually transmitted disease, and family history of cervical cancer are other reasons to turn an HPV infection to the cervical cancer [3]. With the increasing global population, cervical cancer cases are expected to increase 46% until 2030 [4]. Effective prevention and control efforts will …

Spring Discharge Modeling: A Case Study In The Comarca Ngäbe-Buglé, Western Panama, Jordan Mayer

Dissertations, Master's Theses and Master's Reports

Contact (seepage) springs are frequently the only source of potable drinking water for the Ngäbe people located in the Comarca Ngäbe-Buglé, Western Panama. Dry season flows drastically diminish and sometimes dry up, greatly affecting locals’ access to clean drinking water. This study uses MODFLOW 2005 to model two aquifer systems. One is a lab-created, idealized system, and the other is a small, steeply-sloping aquifer in the Comarca Ngäbe-Buglé. Modeling the idealized aquifer demonstrated that MODFLOW 2005 has the capacity to model the dewatering of a steeply sloping aquifer. Modeling the field based aquifer demonstrated that a changing climate (increased temperature …

“Modern Day Slavery”- Implications Of A Label, Mary Graw Leary

Scholarly Articles

Over the last decades much progress has been made in the fight against human trafficking. As with any social movement, divisions exists among activists and scholars on the most effective direction to execute social change. Often, these focus on language. One such critical discussion is whether it is appropriate to label human trafficking “Modern Day Slavery.” Although the term has existed for several years, the analogy gained a more full acceptance with its use by President Obama in September 2012 when he described “the injustice, the outrage, of human trafficking which must be called by its true name -- modern …

Bridging The Justice Gap In Family Law: Repurposing Federal Iv-D Funding To Expand Community-Based Legal And Social Services For Parents, Stacy Brustin, Lisa Vollendorf Martin

Scholarly Articles

Parents in family court overwhelmingly proceed pro se; however, in child support courtrooms, government attorneys representing the state child support agency frequently play a pivotal role. These attorneys represent the state’s ostensible interests in ensuring that children are financially supported and in preventing welfare dependence; they do not represent individual parents. The outcomes of child support proceedings have profound, long-term constitutional and financial implications for parents, yet litigants rarely understand their rights or the role of the government.

Originally, the goal of state child support enforcement efforts was to recapture the costs of welfare expenditures. In 1990, two-thirds of cases …

“Mitigate From Day One”: Why Effective Defense Advocates Do Not Prioritize Liberty Over Life In Death Penalty Cases, Jesse Cheng

Social and Cultural Sciences Faculty Research and Publications

No abstract provided.

Single Particle-Inductively Coupled Plasma-Mass Spectrometry Technology Development For Metallic Nanoparticle Characterization In Complex Matrices, Yongbo Dan

Doctoral Dissertations

"As the rapid growing of nanotechnology, the release of engineered nanoparticles (ENPs) into the environment is inevitable. After entering the real environment, ENPs tend to react with different components of the ecosystem (e.g. water, soil, air, plants) and make their characterization difficult. Analyzing ENPs in these complex matrices still remains as a grand challenge. ENPs characterization is normally the first step of risk assessment. Current analytical techniques have shown some limitations in revealing the unique characteristics of ENPs in complex matrices and reliable analytical techniques are in urgent need. Single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) is an emerging …

Wetting Kinetics In Forced Spreading, Amer Mohammad Al-Shareef

Doctoral Dissertations

"Under dynamic conditions, the dynamic contact angle (the angle that the liquid makes with the solid) of a liquid on a solid surface varies dramatically with substrate velocity from its equilibrium value. Experimental data of the dynamic contact angles for polydimethylsiloxane (PDMS or silicone oil) under air on a glass substrate coated with teflon, for water under PDMS, for solutions of the polymer polyethylene oxide (PEO) under air, for solutions of PEO under PDMS, were obtained to simulate and understand the systems of brine or brine containing a polymer displacing viscous crude. A variety of solid substrates were used other …

The Role Of Pre-Existing Basement Fabrics In The Initiation Of Continental Rifting: The Okavango Rift Zone, Botswana, Angelica Alvarez Naranjo

Doctoral Dissertations

"Integrated geophysical, remote sensing, and field investigations of the Okavango Rift Zone (ORZ), Botswana indicate that a feedback between optimum-oriented basement structures and fluid flow influence the nucleation and growth of continental rifts in their incipient stages. The ORZ, the youngest rift of the East African Rift System, occurs within a Proterozoic inter-cratonic suture zone - the NE-trending Precambrian Damara/Ghanzi-Chobe orogenic belts. The Pleistocene to Holocene ORZ forms a ~450 km long and ~100 km wide half-graben bounded by NE-trending normal faults. Basement units within the Damara/Ghanzi-Chobe orogenic belts exhibit a well-developed NE-trending linear fabric (045-065) defined by parallel limbs …

Novel Design And Manufacturing Strategies For Portable Air-Breathing Proton Exchange Membrane Fuel Cells, Sriram Praneeth Isanaka

Doctoral Dissertations

"The purpose of this dissertation is to study the importance of design novelty and advanced manufacturing and assembly practices towards portable air-breathing proton exchange membrane fuel cells. Traditional proton exchange membrane fuel cell designs have always been based on prismatic shapes and expensive materials like graphite and steel. The novel design strategies theorized as part of this research though have led to the creation of working prototypes with unconventional form factors, materials and manufacturing methods. The benefits include improved reactant flow characteristics, superior power densities, reduced cost, and simplified manufacturing and assembly complexity as compared to conventional proton exchange membrane …

Modeling And Evaluation Of Moisture Diffusion In Polymer Composite Materials, Zhen Huo

Doctoral Dissertations

"Fiber-reinforced polymer composites have extensive applications due to their high specific strength, improved product performance, low maintenance and design flexibility. However, moisture absorbed by polymer composites during the service life plays a detrimental role in both the integrity and durability of composite structure. It is essential to understand the moisture diffusion behavior and induced damage in polymer matrix composites under varying hygrothermal conditions. In Part I, the moisture diffusion characteristics in hybrid composites using moisture concentration-dependent diffusion method have been investigated. Also, a multi-stage diffusion model was proposed to explain the deviation of moisture diffusion behavior for sandwich composites from …

Microwave Material Characterization Of Alkali-Silica Reaction (Asr) Gel In Cementitious Materials, Ashkan Hashemi

Doctoral Dissertations

"Since alkali-silica reaction (ASR) was recognized as a durability challenge in cement-based materials over 70 years ago, numerous methods have been utilized to prevent, detect, and mitigate this issue. However, quantifying the amount of produced ASR byproducts (i.e., ASR gel) in-service is still of great interest in the infrastructure industry. The overarching objective of this dissertation is to bring a new understanding to the fundamentals of ASR formation from a microwave dielectric property characterization point-of-view, and more importantly, to investigate the potential for devising a microwave nondestructive testing approach for ASR gel detection and evaluation. To this end, a comprehensive …

Scale-Up Investigation And Hydrodynamics Study Of Gas-Solid Fluidized Bed Reactor Using Advanced Non-Invasive Measurement Techniques, Abdelsalam Efhaima

Doctoral Dissertations

"This research focuses on validating our newly developed mechanistic scale-up methodology for hydrodynamics similarity of gas-solid fluidized bed reactors (FBRs) by implementing our advanced non-invasive measurement techniques which are gamma ray computed tomography (CT) and radioactive particle tracking (RPT) that measure local hydrodynamic parameters. Experiments were carried out in two fluidized beds of 14 cm and 44 cm in diameter using air as the gas phase and particles of different materials. Since in these reactors the gas dynamic dictates the bed hydrodynamics, the new mechanistic scale-up methodology is based on maintaining similar or closer time averaged radial profiles of gas …

Design, Fabrication, Operation And Aspen Simulation Of Oil Shale Pyrolysis And Biomass Gasification Process Using A Moving Bed Downdraft Reactor, Hassan Golpour

Doctoral Dissertations

"Energy is the major facilitator of the modern life. Every developed and developing economy requires access to advanced sources of energy to support its growth and prosperity. Declining worldwide crude oil reserves and increasing energy needs has focused attention on developing existing unconventional fossil fuels like oil shale and renewable resources such as biomass. Sustainable, renewable and reliable resources of domestically produced biomass comparing to wind and solar energy is a sensible motivation to establish a small-scale power plant using biomass as feed to supply electricity demand and heat for rural development. The work in Paper I focuses on the …

Adaptive Filters For Sparse System Identification, Jianming Liu

Doctoral Dissertations

"Sparse system identification has attracted much attention in the field of adaptive algorithms, and the adaptive filters for sparse system identification are studied. Firstly, a new family of proportionate normalized least mean square (PNLMS) adaptive algorithms that improve the performance of identifying block-sparse systems is proposed. The main proposed algorithm, called block-sparse PNLMS (BS-PNLMS), is based on the optimization of a mixed ℓ_2,1 norm of the adaptive filter's coefficients. A block-sparse improved PNLMS (BS-IPNLMS) is also derived for both sparse and dispersive impulse responses. Meanwhile, the proposed block-sparse proportionate idea has been extended to both the proportionate affine projection …

Synthesis And Functionalization Of A Triaryldiamine-Base Photoconductive/Photorefractive Composite, And Its Application To Aberrated Image Restoration, Yichen Liang

Doctoral Dissertations

"Organic photorefractive (PR) composites have recently emerged as an important class of materials for applications including high-density data storage, optical communication, and biomedical imaging. In an effort to further improve their performance, this study focused on the utilization of functionalized semiconductor nanocrystals to photosensitize triaryamine (TPD)-based PR composites, as well as the application of TPD-based PR composites in the restoration of aberrated optical information. A novel approach to functionalize CdSe quantum dot (QCdSe) was firstly introduced where the sulfonated triarydiamine (STPD) was used as charge-transporting ligand to passivate QCdSe. TPD-based photoconductive and PR composites were photosensitized with the STPD-passivated QCdSe …

On The Spheroidal Graphite Growth And The Austenite Solidification In Ductile Irons, Jingjing Qing

Doctoral Dissertations

"Evolutions of austenite and nodular/spheroidal graphite particles during solidifications of ductile irons were experimentally investigated. Spheroidal graphite particle and austenite dendrite were found nucleated independently in liquid. Austenite dendrite engulfed the spheroidal graphite particles after contact and an austenite shell formed around a spheroidal graphite particle. The graphite diameter at which the austenite shell closed around nodule was determined. Statistically determined graphite size distributions indicated multiple graphite nucleation events during solidification.

Structures in a graphite nodule varied depending on the growth stages of the nodule in ductile iron. Curved graphene layers appearing as faceted growth ledges swept circumferentially around the …

Fully Differential Study Of Projectile Coherence Effects In Ionization Of Molecular Hydrogen And Atomic Helium, Thusitha Priyantha Arthanayaka

Doctoral Dissertations

"It has been well established, that projectile coherent properties are important for the study of atomic fragmentation processes. Recent studies of ionization of molecular hydrogen had demonstrated that measured double differential cross sections (DDCS) are very sensitive to the coherent length of the projectile. These measurements have been performed with varied coherence length of the projectiles by controlling the geometry of the collimating slits, which are placed before the target. Later, fully differential cross sections (FDCS) for a coherent and an incoherent projectile beam has been study for the same collision system and the results confirmed the important role of …

Modeling And Control Of Fuel Cell-Battery Hybrid Energy Sources, Nima Lotfi

Doctoral Dissertations

"Environmental, political, and availability concerns regarding fossil fuels in recent decades have garnered substantial research and development in the area of alternative energy systems. Among various alternative energy systems, fuel cells and batteries have attracted significant attention both in academia and industry considering their superior performances and numerous advantages. In this dissertation, the modeling and control of these two electrochemical sources as the main constituents of fuel cell-battery hybrid energy sources are studied with ultimate goals of improving their performance, reducing their development and operational costs and consequently, easing their widespread commercialization. More specifically, Paper I provides a comprehensive background …

Methodology Investigations For Shear Wave Splitting Analysis, Fansheng Kong

Doctoral Dissertations

"Over the past several decades, shear wave splitting analyses have been increasingly utilized to delineate mantle structure and probe mantle dynamics. However, the reported splitting parameters (fast polarization orientations and splitting times) are frequently inconsistent among different studies, partially due to the different techniques used to estimate the splitting parameters. Here the study conduct research on methodology investigations for shear wave splitting analysis, which are composed of two sub-topics, i.e., a systematic comparison of the transverse minimization (TM) and the splitting intensity (SI) techniques and applicability of the multiple-event stacking technique (MES). Numerical experiments are conducted using both synthetic and …

Modeling Explosive Lensing On A Cylindrical Body In Air: A First Step Towards Sealing An Underwater Offshore Oil Spill, Phillip R. Mulligan

Doctoral Dissertations

"In 2010, the British Petroleum (BP) Deepwater Horizon accident leaked oil into the Gulf of Mexico for 87 days. A fast response method that can seal an oil pipe and stop the release of oil is needed in order to prevent future oil leaks from turning into ecological and financial disasters. Explosives can serve this need.

This research examined how a circular implosive discontinuous explosive lens interacts with a cylindrical surface. The following research was designed to study the applicability of the Method this author developed to predict the peak pressure from multiple shockwaves converging on a centrally located cylinder. …

Low-Complexity Iterative Receiver Algorithms For Multiple-Input Multiple-Output Underwater Wireless Communications, Weimin Duan

Doctoral Dissertations

"This dissertation proposes three low-complexity iterative receiver algorithms for multiple-input multiple-output (MIMO) underwater acoustic (UWA) communications. First is a bidirectional soft-decision feedback Turbo equalizer (Bi-SDFE) which harvests the time-reverse diversity in severe multipath MIMO channels. The Bi-SDFE outperforms the original soft-decision feedback Turbo equalizer (SDFE) while keeping its total computational complexity similar to that of the SDFE. Second, this dissertation proposes an efficient direct adaptation Turbo equalizer for MIMO UWA communications. Benefiting from the usage of soft-decision reference symbols for parameter adaptation as well as the iterative processing inside the adaptive equalizer, the proposed algorithm is efficient in four aspects: …