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Christopher, Yvonne M.Welfare Dependency and Work Ethic: A Quantitative and Qualitative Assessment
Master of Arts (MA), Wright State University, 2017, Applied Behavioral Science: Criminal Justice and Social Problems
This study examined relationships between work ethic and welfare dependency. The 65-item Multidimensional Work Ethic Profile (MWEP) (Miller, Woehr, & Hudspeth, 2002) and the 28-item MWEP (Meriac, Woehr, Gorman, & Thomas, 2013) with attached socioeconomic surveys were administered to n=338 and n=247 adult subjects, respectively. A negative correlation between the two variables was anticipated, so that as levels of agreement with work ethic increase, reported use of welfare benefits decrease. After running correlation matrices to examine Pearson’s r, hierarchical regressions were conducted, culminating in a model which partially predicts the connection between the variables. Bivariate analyses for the 65-item MWEP data indicated that marital status, age, sex, centrality of work, waste time, delayed gratification, self-reliance, morality/ethics, hard work, and leisure were statistically significantly correlated. Bivariate analyses for the 28-item MWEP data indicated that centrality of work and hard work were statistically significantly correlated. These findings could be used in the design of a comprehensive assessment tool to be utilized at the point of entry into the welfare system.

Committee:

Gary Burns, Ph.D. (Committee Chair); Jacqueline Bergdahl, Ph.D. (Committee Co-Chair); Jonathan Varhola, M.A. (Committee Member)

Subjects:

Behavioral Sciences; Demographics; Labor Economics; Public Policy; Social Research; Social Structure; Social Work; Sociology; Statistics; Welfare

Keywords:

Work ethic; welfare; dependency; labor force; unemployment; disability; SNAP; food stamps; TANF; temporary assistance for needy families; welfare reform

Trombley, MichaelDesign of a Programmable Four-Preset Guitar Pedal
Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering
Many companies in the music industry offer programmable preset guitar pedals. Presets allow musicians to save time and focus on their act by recalling predetermined settings during a performance. A majority of the companies in the music industry offer up to hundreds of presets, but realistically the substantial amount of presets may have a negative effect on the musician’s performance due to time constraints. The main contribution of this thesis is to address the musician by reducing the amount of presets offered in a guitar pedal design. Combining two systems, a digital control and audio processing circuit, will produce a programmable four-preset guitar pedal. Cost and size are design constraints that will also be taken into consideration. The techniques observed in this thesis will benefit the music industry because they can be adapted into other guitar pedal designs. This thesis closes with an evaluation of the final design, feedback from musicians in the community, and suggestions for future improvements.

Committee:

Marian Kazimierczuk, Ph.D. (Advisor); Joe Tritschler, Ph.D. (Committee Member); Yan Zhuang, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Guitar; Music; Microcontroller; Programming; Audio; DSP; Digital Signal Processing; Audio Signal Processing;

Dalwadi, NeelNull Values and Null Vectors of Matrix Pencils and their Applications in Linear System Theory
Master of Science in Engineering (MSEgr), Wright State University, 2017, Electrical Engineering
Considerable literature exists in linear algebra to solve the generalized eigenvalue, eigenvector problem (F - λ G)v = 0 where F, G ∈ ℜ(s × s), are square matrices. However, a number of applications lend themselves to the case where F, G ∈ ℜ(s × t), and st. The existing methods cannot be used for such non-square cases. This research explores structural decomposition of a matrix pencil (F - λ G), s ≠ t to compute finite values of λ for which rank(F - λ G) < min(s,t). Moreover, from the decomposition of the matrix pencil, information about the order of λ at infinity, the Kronecker row and column indices of a matrix pencil can also be extracted. Equally important is the computation of non-zero vectors w ∈ ℜ(1 × s) and v ∈ ℜ(t × 1) corresponding to each finite value of λ, such that w(F - λ G) = 0 and (F - λ G)v = 0. Algorithms are developed for the computation of λ, w, and v using numerically efficient techniques. Proposed algorithms are applied to problems encountered in system theory and illustrated by means of numerical examples.

Committee:

Pradeep Misra, Ph.D. (Advisor); Xiaodong Zhang, Ph.D. (Committee Member); Luther Palmer III, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Mathematics

Keywords:

Null Values; Null Vectors; Eigenvalue; Eigenvector; Generalized Eigenvector; Non square; Matrix Pencil; Non square Matrix Pencil; values; vectors; Kronecker Canonical Form; Indices

Khalili, MohsenDistributed Adaptive Fault-Tolerant Control of Nonlinear Uncertain Multi-Agent Systems
Doctor of Philosophy (PhD), Wright State University, 2017, Engineering PhD
The research on distributed multi-agent systems has received increasing attention due to its broad applications in numerous areas, such as unmanned ground and aerial vehicles, smart grid, sensor networks, etc. Since such distributed multi-agent systems need to operate reliably at all time, despite the possible occurrence of faulty behaviors in some agents, the development of fault-tolerant control schemes is a crucial step in achieving reliable and safe operations. The objective of this research is to develop a distributed adaptive fault-tolerant control (FTC) scheme for nonlinear uncertain multi-agent systems under intercommunication graphs with asymmetric weights. Under suitable assumptions, the closed-loop system's stability and leader-follower cooperative tracking properties are rigorously established. First, a distributed adaptive fault-tolerant control method for nonlinear uncertain first-order multi-agent systems is developed. Second, this distributed FTC method is extended to nonlinear uncertain second-order multi-agent systems. Next, adaptive-approximation-based FTC algorithms are developed for two cases of high-order multi-agent systems, i.e., with full-state measurement and with only limited output measurement, respectively. Finally, the distributed adaptive fault-tolerant formation tracking algorithms for first-order multi-agent systems are implemented and demonstrated using Wright State's real-time indoor autonomous robots test environment. The experimental formation tracking results illustrate the effectiveness of the proposed methods.

Committee:

Xiaodong Zhang, Ph.D. (Advisor); Kuldip Rattan, Ph.D. (Committee Member); Pradeep Misra, Ph.D. (Committee Member); Yongcan Cao, Ph.D. (Committee Member); Raul Ordonez, Ph.D. (Committee Member); Mark Mears, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Engineering

Keywords:

Fault-Tolerant Control; Adaptive Control; Multi-Agent Systems; Nonlinear Uncertain Systems; Formation Control; Learning Systems; Cooperative Tracking; Leader-Follower Consensus; Asymmetric Communication Graphs; Fault Diagnosis; Mobile Robots

Balanov, AlekseiWhen Words Are Worse Than Bullets: a Study of Corruption as an Unintended Consequence of Threats of Sanctions
Master of Arts (MA), Wright State University, 2017, International and Comparative Politics
This research contributes to the debates on the efficacy of economic sanctions as a tool of international diplomacy. It focuses on corruption, one of the potential unintended consequences of sanctions. Using multiple regression on a custom cross-sectional time series dataset of more than a thousand observations, this research finds the correlation between threats of sanctions and level of corruption statistically significant. The model suggests each new round of threats translates into a 1.25% increase in corruption for relatively clean states and a 5% increase for already corrupt states. The resulting policy implications are examined in this thesis.

Committee:

Liam Anderson, Ph.D. (Committee Chair); Carlos Costa, Ph.D. (Committee Member); December Green, Ph.D. (Committee Member)

Subjects:

International Relations; Political Science

Keywords:

Corruption; sanctions; threats; unintended; consequences; statistics; quantitative; analysis; cross-country; cross-sectional; time; series

Joshi, Amit KrishnaExploiting Alignments in Linked Data for Compression and Query Answering
Doctor of Philosophy (PhD), Wright State University, 2017, Computer Science and Engineering PhD
Linked data has experienced accelerated growth in recent years due to its interlinking ability across disparate sources, made possible via machine-processable RDF data. Today, a large number of organizations, including governments and news providers, publish data in RDF format, inviting developers to build useful applications through reuse and integration of structured data. This has led to tremendous increase in the amount of RDF data on the web. Although the growth of RDF data can be viewed as a positive sign for semantic web initiatives, it causes performance bottlenecks for RDF data management systems that store and provide access to data. In addition, a growing number of ontologies and vocabularies make retrieving data a challenging task. The aim of this research is to show how alignments in the Linked Data can be exploited to compress and query the linked datasets. First, we introduce two compression techniques that compress RDF datasets through identification and removal of semantic and contextual redundancies in linked data. Logical Linked Data Compression is a lossless compression technique which compresses a dataset by generating a set of new logical rules from the dataset and removing triples that can be inferred from these rules. Contextual Linked Data Compression is a lossy compression technique which compresses datasets by performing schema alignment and instance matching followed by pruning of alignments based on confidence value and subsequent grouping of equivalent terms. Depending on the structure of the dataset, the first technique was able to prune more than 50% of the triples. Second, we propose an Alignment based Linked Open Data Querying System (ALOQUS) that allows users to write query statements using concepts and properties not present in linked datasets and show that querying does not require a thorough understanding of the individual datasets and interconnecting relationships. Finally, we present LinkGen, a multipurpose synthetic Linked Data generator that generates a large amount of repeatable and reproducible RDF data using statistical distribution, and interlinks with real world entities using alignments.

Committee:

Pascal Hitzler , Ph.D. (Advisor); Guozhu Dong, Ph.D. (Committee Member); Krishnaprasad Thirunaraya, Ph.D. (Committee Member); Michelle Cheatham, Ph.D. (Committee Member); Subhashini Ganapathy, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

Linked Data; RDF Compression; Ontology Alignment; Linked Data Querying; Synthetic RDF Generator; SPARQL

Pyles, David T.Effects of the Kinematic Model on Forward-Model Based Spotlight SAR ECM
Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering
Spotlight synthetic aperture radar (SAR) provides a high-resolution remote image formation capability for airborne platforms. SAR image formation processes exploit the amplitude, time, and frequency shifts that occur in the transmitted waveform due to electromagnetic propagation and scattering. These shifts are predictable through the SAR forward model which is dependent on the waveform parameters and emitter flight path. The approach to develop an electronic countermeasure (ECM) system that is founded on the SAR forward model implies that the ECM system should alter the radar’s waveform in a manner that produces the same amplitude, time, and frequency shifts that a real scatterer would produce at a desired location. A collection of such scatterers would be capable of forming a larger collective energy distribution in the final image. However, since the forward model is dependent on the radar platform’s kinematic model, the jamming energy distribution created from a forward-model based ECM system will inherently have some level of sensitivity to kinematic error. This thesis discusses a forward-model based ECM modulation scheme and provides an assessment of its sensitivity through Monte Carlo simulations and an entropy-based image similarity distance.

Committee:

Michael A. Saville, Ph.D. (Committee Chair); Brian Rigling, Ph.D. (Committee Member); Steve Gorman, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

electrical engineering; spotlight synthetic aperture radar; SAR

Jackson, Eric AlanTowards a Prediction of Landscape Evolution from Chemical Weathering and Soil Production
Master of Science (MS), Wright State University, 2017, Physics
The time evolution of a periodic landscape under the influence of chemical weathering and physical erosion is computed. The model used incorporates weathering and soil production as a flux limited reaction controlled by groundwater flow. Scaling of the flow rate is obtained from a percolation theoretic treatment. The erosion of the soil material produced by this process is modeled by the diffusion of elevation, as consistent with downslope soil transport proportional to the tangent of the angle of the topography, and application of the equation of continuity to surface soil transport. Three initial topographies are examined over a periods of thousands of years and resulting landforms and soil productivity compared. Differences in productivity between these cases are found to occur primarily within a short time span of hundreds of years. Times for propagation of a disturbance in one layer to another are also obtained.

Committee:

Allen Hunt, Ph.D. (Advisor); Jerry Clark, Ph.D. (Committee Member); Thomas Skinner, Ph.D. (Committee Member)

Subjects:

Environmental Science; Physics

Keywords:

soil production; percolation; erosion; diffusion; landscape evolution; groundwater; solute transport

Gabbard, Ryan DwightIdentifying the Impact of Noise on Anomaly Detection through Functional Near-Infrared Spectroscopy (fNIRS) and Eye-tracking
Master of Science in Biomedical Engineering (MSBME), Wright State University, 2017, Biomedical Engineering
Occupational noise frequently occurs in the work environment in military intelligence, surveillance, and reconnaissance (ISR) operations. This impacts cognitive performance by acting as a stressor, potentially interfering with the analysts’ decision making process. In this study the effects of different noise stimuli on analysts’ performance and workload in anomaly detection were investigated by simulating a noisy work environment. Functional near infrared spectroscopy (fNIRS) was utilized to quantify oxy-hemoglobin (HbO) and deoxy-hemoglobin (HbD) concentration changes in the prefrontal cortex (PFC), as well as behavioral measures which include eye-tracking, reaction time, and accuracy rate. It was found that HbO for some of the channels analyzed were significantly different across noise types (p<0.05). The results indicated that HbO activation for short intermittent noise stimuli was greater in the PFC compared to long intermittent noises. Target transition rates were also significantly higher (p<0.05) for no noise conditions compared to noise filled environments. These approaches using fNIRS in conjunction with an understanding of the impact on human analysts in anomaly detection, could potentially lead to better performance by optimizing work environments.

Committee:

Mary Fendley, Ph.D. (Advisor); Nasser Kashou, Ph.D. (Committee Member); Rik Warren, Ph.D. (Committee Member)

Subjects:

Biomedical Engineering; Neurosciences

Keywords:

functional near-infrared spectroscopy; workload; prefrontal cortex; eye tracking; noise; anomaly detection

Rematska, GiorgiaA Stochastic Petri Net Reverse Engineering Methodology for Deep Understanding of Technical Documents
Doctor of Philosophy (PhD), Wright State University, 2018, Computer Science and Engineering PhD
Systems Reverse Engineering has gained great attention over time and is associated with numerous different research areas. The importance of this research derives from several technological necessities. Security analysis and learning purposes are two of them and can greatly benefit from reverse engineering. More specifically, reverse engineering of technical documents for deeper automatic understanding is a research area where reverse engineering can contribute a lot. In this PhD dissertation we develop a novel reverse engineering methodology for deep understanding of architectural description of digital hardware systems that appear in technical documents. Initially, we offer a survey on reverse engineering of electronic or digital systems. We also provide a classification of the research methods within this field, and a maturity metric is presented to highlight weaknesses and strengths of existing methodologies and systems that are currently available. A technical document (TD) is typically composed by several modalities, like natural language (NL) text, system’s diagrams, tables, math formulas, graphics, pictures, etc. Thus, for automatic deep understanding of technical documents, a synergistic collaboration among these modalities is necessary. Here we will deal with the synergistic collaboration between NL-text and system’s diagrams for a better and deeper understanding of a TD. In particular, a technical document is decomposed into two modalities NL-text and figures of system’s diagrams. Then, the NL-text is processed with a Natural Language text Understanding (NLU) method and text sentences are categorized into five categories, by utilizing a Convolutional Neural Network to classify them accordingly. While, a Diagram-Image-Modeling (DIM) method processes the figures by extracting the system’s diagrams. More specifically, NLU processes the text from the document and determines the associations among the nouns and their interactions, by creating their stochastic Petri-net (SPN) graph model. DIM performs processing/analysis of figures to transform the diagram into a graph model that holds all relevant information appearing in the diagram. Then, we combine (associate) these models in a synergistic way and create a synergistic SPN graph. From this SPN graph we obtain the functional specifications that form the behavior of the system in a form of pseudocode. In parallel we extract a flowchart to enhance the understanding that the reader could have about the pseudocode and the hardware system as a unity.

Committee:

Nikolaos Bourbakis, Ph.D. (Advisor); Soon Chung, Ph.D. (Committee Member); Bin Wang, Ph.D. (Committee Member); Sukarno Mertoguno, Ph.D. (Committee Member)

Subjects:

Computer Engineering; Computer Science

Keywords:

systems reverse engineering; reverse engineering; technical document; stochastic Petri-net;

Beesetty, PavaniConsequences of TRPM7 kinase inactivation in immune cells
Doctor of Philosophy (PhD), Wright State University, 2018, Biomedical Sciences PhD
The characteristic feature of ubiquitously expressed transient receptor potential melastatin 7 (TRPM7) protein is the presence of a C-terminal atypical kinase domain fused to a cation channel domain. Even though this protein has been implicated in a number of physiological and pathological processes, the mechanisms regulating TRPM7 channel activity are poorly understood. In the present study, regulation of TRPM7 channel by its kinase activity was investigated using the TRPM7 kinase-dead knock-in mouse (KD mouse). These mice have a point mutation Lys1646Arg in the kinase region abrogating the kinase activity. Examining TRPM7 channel activity in KD peritoneal macrophages revealed that TRPM7 kinase activity is not required for channel activity yet may reduce the number of channels functioning in an intact cell. Thus, kinase activity is dispensable for the formation of functional TRPM7 channels, in agreement with previous studies done in overexpression systems. T lymphocytes isolated from KD mice showed reduced blastogenesis, proliferation and cytokine expression upon activation, potentially due to defective up-regulation of Ca2+ and Mg2+ dependent pathways. The up-regulation of the primary calcium entry pathway in activated T cells, the store-operated calcium entry, and calcium elevations in response to T-cell receptor ligation were impaired in KD T cells. TRPM7 protein levels were increased in both WT and KD mouse T cells upon activation. Additionally, KD mice exhibited splenomegaly and increased extramedullary hematopoiesis, along with a modest pre-activation of T cells. The present work provides insights into the physiological role of TRPM7 kinase in regulating its channel activity and immune cell function.

Committee:

J. Ashot Kozak, Ph.D. (Advisor); Gerald M. Alter, Ph.D. (Committee Member); Dan R. Halm, Ph.D. (Committee Member); F. Javier Alvarez-Leefmans, Ph.D. (Committee Member); Kathrin Engisch, Ph.D. (Committee Member)

Subjects:

Immunology; Physiology

Keywords:

blastogenesis; TRPM7; TRPM6; store-operated calcium entry; splenomegaly; interleukin 2

Grugan, Cecilia SpencerDisability Resource Specialists’ Capacity to Adopt Principles and Implement Practices that Qualify as Universal Design at a 4-Year Public Institution
Master of Arts (MA), Wright State University, 2018, Educational Leadership
Due to the continuous growth of diverse student bodies on college campuses, creating accessibility for each unique student needs to be considered. Students who have a disability or disabilities are a substantial part of this growing diverse student body. Since disability resource specialists play a significant role in creating accessibility for such students, they can consider implementing practices that qualify as Universal Design. The purpose of this phenomenological study was to explore where disability resource specialists fall on Lewin’s (1951) continuum of change and Reynold’s (2009) levels of expertise in regards to implementing practices that qualify as Universal Design. Six participants were included in this study out of eight who were invited to participate. Out of those six participants, the study showed that all participants demonstrated a strong presence in the Unfreezing stage of Lewin’s (1951) continuum of change. Also, the study showed that all participants showed a level of knowledge as the second tier to Reynold’s (2009) levels of expertise. Limitations as well as recommendations for future research included recruiting a larger sample of participants to provide greater analysis of the study.

Committee:

Carol Patitu, Ph.D. (Advisor); Suzanne Franco, Ed.D. (Committee Member); Stephanie Krah, Ph.D. (Committee Member)

Subjects:

Communication; Community College Education; Community Colleges; Curricula; Curriculum Development; Design; Education; Education Policy; Educational Evaluation; Educational Leadership; Educational Theory; Engineering; English As A Second Language; Experiments; Instructional Design; Intellectual Property; Labor Relations; Management; Mass Communications; Mental Health; Minority and Ethnic Groups; Multicultural Education; Occupational Health; Occupational Therapy; Personal Relationships; Public Administration; Public Health; Public Health Education; Public Policy; Reading Instruction; Recreation; Rehabilitation; Robotics; Robots; School Administration; Secondary Education; Special Education; Speech Therapy; Systems Design; Teacher Education; Transportation

Keywords:

Universal Design; Accommodations; Accessibility; Organizational Change; Proactive Practices; Disability; Disability Resource Specialists; Disability Services; Higher Education; Student Affairs

Haman, Kayla MarieLead in tap water from the City of Dayton, Ohio
Master of Science (MS), Wright State University, 2018, Earth and Environmental Sciences
Lead (Pb) in public tap water is a national health concern and is the main pathway of human exposure to Pb. The City of Dayton has verified Pb pipelines and homes with Pb plumbing; thus, residents are at risk to Pb leaching into their tap water. I sampled water from 130 residential and 24 public water taps and measured Pb and copper (Cu). Five percent of samples exceeded the action level for Pb (> 15 µg/L) and none exceeded the action level for Cu. The City of Dayton’s lead pipeline map identifies potential Pb exposure from Pb distribution pipes. However, the samples that exceeded Pb action level were from the first draw, indicating Pb-bearing plumbing and fixtures within Dayton homes drives Pb concentrations in my dataset. Most of the samples that exceeded action level were from homes assessed below Dayton’s median household value and built before 1986.

Committee:

Chad Hammerschmidt, Ph.D. (Advisor); Silvia Newell, Ph.D. (Committee Member); Robert Ritzi, Ph.D. (Committee Member)

Subjects:

Public Health

Keywords:

lead; tap water; public health; lead and copper rule

Goodman, Caitlin Elizabeth A Novel Method to Analyze DNA Breaks and Repair in Human Cells
Master of Science (MS), Wright State University, 2018, Biochemistry and Molecular Biology
Microsatellites repeat sequences are prone to forming non-canonical DNA structures and mutations. These areas of the genome can undergo expansions and contractions and are responsible for a variety of inherited neurological and neuromuscular disorders. Hairpin structures formed by trinucleotide repeats can lead to replication fork stalling, and fork collapse causing DNA double strand breaks. Various mechanisms are involved in processing microsatellites including mismatch repair, base excision repair, and crossover junction endonuclease cleavage. These processes, which are supposed to protect the genome, could also be the culprits which are causing mutations. In order to test and study this hypothesis, the use of a two color marker gene assay to detect DNA double strand breaks at trinucleotide repeats, was used to detect replication fork stalling, and collapse in presence or absence of replication stress. An important mechanism for the restart of a stalled replication fork involves crossover junction endonucleases, which cleave obstacles that prevent passage of the replication fork. This process is led by MUS81 and its associates EME1 and EME2, which form complexes to process these secondary structures allowing the replication fork to progress. My results indicate distinct roles for MUS81-EME1 and MUS81-EME2 complexes in the maintenance of genome stability.

Committee:

Michael Leffak, Ph.D. (Advisor); Michael Markey, Ph.D. (Committee Member); Weiwen Long, Ph.D. (Committee Member)

Subjects:

Biochemistry; Molecular Biology

Keywords:

Microsatellite; DNA; Double strand break; DSB; CTG; expanded microsatellite; MUS81; EME1; EME2; CTG CAG; crossover junction endonuclease; trinucleotide repeat; replication stress; hairpin; secondary structure

Boehm, Robert C.The role of substrate mechanics in nanotoxicity mediated by endocytosis
Master of Science (MS), Wright State University, 2017, Pharmacology and Toxicology
Presented in this work is the development of a novel variable modulus, porous PDMS-membrane based ALI cell culture model to assess cell growth under tissue matched stiffness conditions, tight-junction formation, and response to nanoparticle (NP) exposures. Using Sylgard 184 and 527 polydimethylsiloxane (PDMS) and corn syrup emulsions, produced 5 micron thick, highly porous membranes. Membranes spanning 1 kPa-1000 kPa have been achieved, modeling both healthy and fibrotic physiological lung tissue stiffness respectively. Scaffold microstructure and mechanics, cellular proliferation and viability under submerged and ALI conditions, were assessed. The viability was assessed using a Guava 12HT flow cytometer with Viacount reagent. Submerged exposure to 30 nm tannic acid stabilized gold or zinc oxide will be conducted for 8, 24, and 48 hours at 0, 1, 5, 10, 20, and 100 µg/ml. Inductively coupled plasma-mass spectrometry (ICP-MS) will be performed on the apical supernatants. A model system capable of capturing the unique mechanics and membrane properties found at the alveolar-endothelial interface could better predict toxicity, safe levels of exposure, and provide a rapid-means to assess new materials, pharmacologics, or potentially hazard chemicals.

Committee:

Saber Hussain, Ph.D. (Advisor); Mark Nelson, Ph.D. (Committee Member); Terry Oroszi, Ed.D. (Committee Member)

Subjects:

Toxicology

Keywords:

PDMS; Modulus; toxicology; A549

Mao, DavinBistatic SAR Polar Format Image Formation: Distortion Correction and Scene Size Limits
Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering
The polar format algorithm (PFA) for bistatic synthetic aperture radar (SAR) image formation offers the compromise between image quality and computational complexity afforded by PFA, while enabling the geometric flexibility of a bistatic collection scenario. The use of the far-field approximation (FFA), which enables the use of the two-dimensional (2D) fast Fourier transform (FFT) in PFA, introduces spatially-varying distortion and defocus effects causing geometric warping and blurring in the resulting image. In this thesis, the residual phase errors due to the FFA are analyzed by decomposing the residual phase errors in the time dimension into their constant, linear, and quadratic Taylor series components. Based on the analysis, a 2D interpolation-based distortion correction technique is developed, and accurate scene size limits are derived for the corrected image to mitigate the effects of defocus. The phase error analysis is conducted with respect to arbitrary transmitter and receiver trajectories, and examples are demonstrated for both the ideal linear and ideal circular flight geometries using a point target scene simulation.

Committee:

Brian Rigling, Ph.D. (Advisor); Michael Saville, Ph.D. (Committee Member); Joshua Ash, Ph.D. (Committee Member)

Subjects:

Electrical Engineering; Remote Sensing

Keywords:

bistatic radar, synthetic aperture radar, polar format algorithm, distortion, defocus, scene size limits

Sangle, Sagar DilipDesign and Testing of Scalable 3D-Printed Cellular Structures Optimized for Energy Absorption
Master of Science in Mechanical Engineering (MSME), Wright State University, 2017, Mechanical Engineering
Sandwich panel structures are widely used due to their high compressive and flexural stiffness and strength-to-weight ratios, good vibration damping, and low through-thickness thermal conductivity. These structures consist of solid face sheets and low-density cellular core structures that are often based upon honeycomb topologies. Interest in additive manufacturing (AM), popularly known as 3D printing (3DP), has rapidly grown in past few years. The 3DP method is a layer-by-layer approach for the fabrication of 3D objects. Hence, it is very easy to fabricate complex structures with complex internal features that cannot be manufactured by any other fabrication processes. Due to the recent advancement of 3DP processes, the core lattice configurations can be redesigned to improve certain properties such as specific energy absorption capabilities. This thesis investigates the load-displacement behavior of 3D printable lattice core structures of five different configurations and rank them according to their specific energy absorption under quasi-static loads. The five different configurations are body centered cubic (bcc) diamonds without vertical struts; bcc diamonds with vertical alternate struts, tetras, tetrahedrons, and pyramids. First, both elastic and elastic-plastic finite element analysis (FEA) approach was used to find optimum cell dimension for each configuration. Cell size and strut diameter were varied for each configuration, the energy absorption during compression were calculated, and the optimum dimension was identified for each configuration. Next, the optimized designs were printed using acrylonitrile butadiene styrene (ABS) polymer to evaluate their compression behavior. Fused deposition modeling based Stratasys uPrint printer was used for printing the samples. After printing the samples, all five designs of lattice structures were subjected to compression load and their load-displacement behavior were analyzed and compared. From both FEA calculations and experimental results, the five configurations can be placed as tetrahedrons, pyramids, tetras, BCC diamonds with struts, and diamonds without struts, the first one having the highest and the last one having the lowest energy absorption capabilities. A detailed discussion on the FEA modeling, sample fabrication, and testing of different configurations is presented in the thesis report.

Committee:

Raghavan Srinivasan, Ph.D. (Committee Co-Chair); Ahsan Mian, Ph.D. (Committee Co-Chair); Joy Gockel, Ph.D. (Committee Member)

Subjects:

Mechanical Engineering

Keywords:

Lattice structures; energy absorption; 3D printing; additive manufacturing; compression testing; finite element analysis

Robinson, Jace D.A Model for Seasonal Dynamic Networks
Master of Science (MS), Wright State University, 2018, Computer Science
Sociotechnological and geospatial processes exhibit time varying structure that make insight discovery challenging. This paper presents statistical model of systems with seasonal dynamics, modeled as a dynamic network, to address this challenge. It assumes the probability of edge formations depend on a type assigned to incident nodes and the current time. Time dependencies are modeled by unique seasonal processes. The model is studied on several synthetic and real datasets. Superior fidelity of this model on seasonal datasets compared to existing network models, while being able to remain equally accurate for networks with randomly changing structure, is shown. The model is found to be twice as accurate at predicting future edge counts over competing models on New York City taxi trips, U.S. airline flights, and email communication within the Enron company. An anomaly detection use case for the model is shown for NYC traffic dynamics and email communications between Enron employees.

Committee:

Derek Doran, Ph.D. (Committee Chair); Tanvi Banerjee, Ph.D. (Committee Member); Fred Garber, Ph.D. (Committee Member)

Subjects:

Artificial Intelligence; Computer Science; Information Science

Keywords:

Stochastic Blockmodel; Dynamic Networks; Seasonal Time Series; Kalman Filter

Brower, Cheyna KatherineToo Long and Too Boring: The Effects of Survey Length and Interest on Careless Responding
Master of Science (MS), Wright State University, 2018, Human Factors and Industrial/Organizational Psychology MS
Careless responding (CR), also called insufficient effort responding (IER), occurs when survey participants respond to items without regard to item content. The presence of careless responding threatens the validity of inferences made from self-report data (Huang et al., 2012; Huang et al., 2015). This study examines the effects of two proposed causes of careless responding (Mead & Craig, 2012): questionnaire length and participant disinterest. Specifically, I hypothesized that (a) questionnaire length is positively related to careless responding, (b) participant interest is negatively related to careless responding, and (c) questionnaire length has a weaker relationship with careless responding among participants who are interested in the questionnaire content than among participants who are uninterested in the questionnaire content. Analyses using a sample of 316 undergraduate students, who were randomly assigned to either a long survey or short survey condition, provided partial support for the three hypotheses tested. I found significant mean differences (d = 0.29 to 0.42) in careless responding that indicated a lower prevalence of careless responding in the short survey condition than the long survey condition. I found significant negative correlations (r = -.12 to -.21) indicating that interest has a negative relationship with careless responding. Additionally, interest moderated the relationship between questionnaire length and careless responding such that participants with low interest in the long survey condition display significantly more careless responding as measured by the infrequency scale than those in the short survey condition. These findings have important theoretical and practical implications for researchers and practitioners that use self-report surveys.

Committee:

Nathan Bowling, Ph.D. (Committee Chair); Gary Burns, Ph.D. (Committee Member); David LaHuis, Ph.D. (Committee Member)

Subjects:

Personality; Personality Psychology; Psychological Tests; Psychology

Keywords:

careless responding; insufficient effort responding; self-report surveys; survey length; questionnaire length; interest

Ali, Ali HasanModifying Some Iterative Methods for Solving Quadratic Eigenvalue Problems
Master of Science (MS), Wright State University, 2017, Mathematics
In this thesis, we are investigating the solutions λ of a typical quadratic eigenvalue problem (QEP). Indeed, solutions λ of a QEP of the form Q(λ)=λ2M+λD+S that satisfy Q(λ)=0, can be obtained iteratively and without linearizing the problem. However, many iterative methods can only find some of the solutions λ. Therefore, we are going to modify a method based on Newton iterations in order to find all of the solutions λ, that are known also as the eigenvalues of the QEP. In addition, we will investigate how the proposed method compares with standard iterative methods from the literature. Moreover, we will provide a method for finding an upper bound for the number of the eigenvalues of the QEP, and apply this in our method for the purpose of finding all solutions λ.

Committee:

Sara Pollock, Ph.D. (Advisor); Yuqing Chen, Ph.D. (Committee Member); Weifu Fang, Ph.D. (Committee Member)

Subjects:

Applied Mathematics; Mathematics

Keywords:

Quadratic Eigenvalue problem; Matrix Polynomial Problem; Nonlinear Eigenvalue Problem; Newton Iteration; Generalized Eigenvalue Problem; Newton Maehly Method; Newton Maehly Iteration; Newton Correction; QEP; NLEP; NLEVP; MPP; GEP

Brackett, Nathaniel Incorporation of Indeno[2,1-c]fluorenes into Polymers via Nucleophilic Aromatic Substitution
Master of Science (MS), Wright State University, 2017, Chemistry
A difluoro indeno[2,1-c]fluorene monomer was synthesized by a four-step process. The first compound synthesized by a two-step process was 2,5- bis(ethoxycarbonyl)-3,4-di(4-fluorophenyl)cyclopentadienone. The next two compounds synthesized were diethyl 2,3-bis(fluorophenyl)-5-hexylterephthalate and 2,3- bis(fluorophenyl)-5-hexylterephthalic acid. The final step involved an intramolecular Friedel-Crafts acylation of the terephthalic acid derivative to form 3,10-difluoro-5,8- dioxo-5,8-dihydro-6-hexylindeno[2,1-c]fluorene. The difluoro monomer was reacted in a series of nucleophilic aromatic substitution (NAS) polymerization reactions with bisphenol-A in N-methyl-pyrrolidone (NMP) in an attempt to form novel poly(ether ether ketone ketone)s containing the indeno[2,1-c]fluorene structure. Analysis of the product by NMR and TLC showed the reaction was unsuccessful and the difluoro monomer did not undergo significant fluorine displacement. A series of model reactions in NMP and dimethyl sulfoxide (DMSO) also confirmed that the monomer did not undergo fluorine displacement under polymerization conditions. In addition, the synthesis of diethyl 5,6- diphenyl-2,3-bis(2-thienyl)terephthalate and 2,8-dibromo-5,11-bis(4-bromophenyl)- indeno[1,2-b]fluorene-6,12-dione were carried out.

Committee:

William Feld, Ph.D. (Advisor); Eric Fossum, Ph.D. (Committee Member); Kenneth Turnbull, Ph.D. (Committee Member)

Subjects:

Chemistry

Keywords:

chemistry

Merrell, Thomas WilliamEvaluation of Consumer Drone Control Interface
Master of Science in Industrial and Human Factors Engineering (MSIHE) , Wright State University, 2018, Industrial and Human Factors Engineering
The development and use of consumer grade drones is becoming a larger part of our society for many different applications. There has been a great amount of discussion and constant review of proper operation of consumer drones including proper methods of control. In turn, regulation of such devices has been inconsistent. This study aims to better understand the effects of the three primary control interface methods (line of sight, video aided, and first-person view) on flight performance, situational awareness, and perceived mental workload of the operator. Secondarily, this study aims to provide design recommendations for future interfaces. This study shows that the first-person view control interface results in a longer flight time around a course, higher mental workload, and lower situational awareness when compared to line-of-sight and video aided control. The use of line-of-sight control performed superiorly in all areas, and the video-aided interface was very close behind.

Committee:

Subhashini Ganapthy, Ph.D. (Advisor); Mary Fendley, Ph.D. (Committee Member); Sasanka Prabhala, Ph.D. (Committee Member)

Subjects:

Engineering; Industrial Engineering; Neurosciences

Keywords:

usability; mental workload; situational awareness; consumer drone; interface design

Douglas, DanMao Zedong and Xi Jinping: A Trait Analysis
Master of Arts (MA), Wright State University, 2017, International and Comparative Politics
This study uses Margaret Hermann’s Leadership Trait Analysis (LTA) to compare Mao Zedong and Xi Jinping and see if they have the same style. Through a content analysis of a leader’s speeches, researchers can gain insight into a leader’s motivation for obtaining office and power. In the course of this research, 167 speeches by Mao, and 79 Speeches by Xi were inputted into the content analysis program Profiler+ (Hermann, 2003). The analysis showed that Mao and Xi have some similarities in their LTA results, but the differences in their scores indicate different approaches to leadership. An analysis of the context of a sample of speeches indicated that Mao was more likely to break society into groups and to be distrustful of others than Xi. The research concludes, Mao was a revolutionary and Xi is a bureaucrat and they utilize different leadership styles in response to their environments.

Committee:

Laura Luehrmann, Ph. D. (Committee Chair); Judson Murray, Ph. D. (Committee Member); Vaughn Shannon, Ph. D. (Committee Member)

Subjects:

Political Science

Keywords:

Leadership Studies; Leadership Trait Analysis; China; Mao Zedong; Xi Jinping; Chinese Communist Party; Speeches; Political Psychology

Douglas, Billy MichaelExplaining Nuclear Rollback: Examining the Cessation of Nuclear Weaponization in Argentina and Brazil from 1964 – 1994
Master of Arts (MA), Wright State University, 2018, International and Comparative Politics
Seventy years after the first use of nuclear weapons in World War II, the proliferation of these apocalyptic munitions remains a key policy issue on the international stage. The available literature on nuclear proliferation suggests a strong correlation between the threat of rival a state seeking nuclear weapons and a state’s own decision to pursue its own nuclear weapons. Regional rivals Argentina and Brazil both initiated nuclear weapons programs and were also developing nuclear delivery systems; however, these countries were able to step out of this dyadic proliferation spiral and renounced their nuclear weapons programs. Often assumed a success of the burgeoning nonproliferation regime embodied by the Nuclear Non-Proliferation Treaty, some scholars view Argentina and Brazil as boldly resistant to the aggressive posture of the extra-regional regime. Which International Relations (IR) theory is best suited to explain the proliferation outcomes of Argentina and Brazil? More specifically, were Argentina and Brazil’s nuclear proliferation decisions driven more by security, norms, or domestic politics? A case study of this dyad will be done using process tracing to determine which theory best supports the nuclear re-posturing of each country.

Committee:

Liam Anderson, Ph.D. (Committee Chair); Carlos Costa, Ph.D. (Committee Member); Vaughn Shannon, Ph.D. (Committee Member)

Subjects:

International Relations; Political Science

Keywords:

Argentina; Brazil; Nuclear; Weapon; weaponization; WMD;

Alsaeed, KalelDetermination of the Shape of a Flattening Filter Free (FFF) Radiation Beam When Modified by a Physical Wedge
Master of Science (MS), Wright State University, 2017, Physics
The determination of a flattening filter free (FFF) beam profile when the collimator is intentionally modified to incorporate a physical wedge. Specifically, radiation beam profiles change shape when a metallic wedge is placed in the path of the beam. Examination of this unknown is necessary to ascertain whether a physical wedge is clinically beneficial for applications involving FFF beams. The aim of this study is to determine if the radiation profile of a flattening filter free beam having a physical wedge is comparable to a beam with a flattening filter, with the same wedge inserted. This research involves measurement of relative dose along the wedged plane. A commercially available particle accelerator was used for this study, which was capable of producing 6 MV bremsstrahlung x-rays. Only beams operating at 6 MV were considered for the investigation. The results indicate that Wedged profiles are similar in many respects when a FFF beam uses the same physical wedge designed for flattening filter beams. Differences in wedged profiles between the FFF and FF beams are discussed.

Committee:

Brent Foy, Ph.D. (Advisor); Sarah Tebbens, Ph.D. (Committee Member); Michael Gossman, M.S. (Committee Member)

Subjects:

Physics

Keywords:

Wedge; FFF beam; FF beam; using wedge with FFF beam

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