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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

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

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

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

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

Yang, JianpingSynthesis and Characterizations of Lithium Aluminum Titanium Phosphate (Li1+xAlxTi2-x(PO4)3) Solid Electrolytes for All-Solid-State Li-ion Batteries
Master of Science in Materials Science and Engineering (MSMSE), Wright State University, 2017, Materials Science and Engineering
New-generation low-emission transportation systems demand high-performance lithium ion (Li-ion) batteries with high safety insurance at broad operable temperatures. Highly conductive solid electrolyte is one of the key components for such applications. The objective of this thesis is to synthesize and characterize aluminum doped lithium titanium phosphate, i.e. Li1+xAlxTi2-x(PO4)3 (LATP), one of the solid-state electrolytes for potential applications to all solid-state lithium-ion batteries. In this research, sol-gel method and one step solid-state reaction approaches were explored and critical processes were optimized towards maximizing lithium ion conductivities at room temperature. The impacts of the processing conditions on the structures, morphologies, compositions of the LATP products, and lithium ion conductions were presented. Particle growth kinetics and lithium ion conduction mechanism were briefly discussed. The highest conductivities of LATPs achieved via the sol-gel and solid-state synthesis are 1.24E-04 S/cm and 1.86E-04 S/cm, respectively, exhibiting the feasibilities of applying them to all-solid-state Li-ion batteries.

Committee:

Hong Huang, Ph.D. (Advisor); Allen Jackson, Ph.D. (Committee Member); Raghavan Srinivasan, Ph.D. (Committee Member)

Subjects:

Materials Science

Keywords:

materials science

Alsabri, Sami Gamaleddin F.Usage of Extracellular Microvesicles as Novel and Promising Therapeutic Tool in Wound Healing
Master of Science (MS), Wright State University, 2017, Pharmacology and Toxicology
Introduction Extracellular Microvesicles (EMVs) can carry genetic messages and biologically active proteins throughout tissues and the body. Because of their transport capabilities, EMVs play an important role both diseased and healthy conditions. For example, EMVs play an important regenerative role in many damaged tissues. In the current studies, we examine the role of EMVs in epithelial wound healing. The potential use of EMVs as drug delivery vehicles has gained considerable scientific interest because they can be delivered in circulation, can be targeted to specific areas/cells, and can pass natural barriers. In the current work, we investigate the potential of EMVs or EMVs loaded with growth factors as a tool to enhance cell migration in order to accelerate epithelial wound healing. Material and Methods Spontaneously immortalized skin keratinocyte and macrophage cells were stressed for 48 h by serum free media to enhance the release of the EMVs from keratinocytes (KMVs) and macrophages (MMV). The EMVs from both cell lines were isolated and collected using a centrifugation process. Specifically, the collected serum free media were centrifuged at 4 °C (500 × g for 10 minutes followed by 2,000 × g for 20 minute). The supernatant was then centrifuged at 24,000 × g for 2 hours to isolate EMVs. EMVs were “loaded” with growth factors by incubating them for 1.5 h at room temperature with PDGF, TGF-ß, VEGF, and FGF (25ng/ml per each). These “loaded” EMVs were then ultra-centrifuged at 176,000 x g for 3 h to re-pellet the loaded microveiscles derived from keratinocytes KMVs (LKMVs) or macrophages MMVs (LMMVs). In order to evaluate the role of microvesicles on cutaneous wound healing, we chose the in vitro wound scratch assay to evaluate the cell migration rate and the wound healing percent after adding of KMVs, LKMVs, MMVs, and LMMVs separately to Epidermal keratinocytes culture. Epidermal keratinocytes were plated into 6 well plates, and wound scratch was made using 10 µl pipette tip. The model was visualized by 10 x magnification power of EVOS XL Core Cell Imaging System and analyzed using Mat lab software to measure wound area. MTT assay was used to evaluate the proliferative effect of KMVs, LKMVs, MMVs, and LMMVs on Epidermal keratinocytes. The loading was confirmed by using BioPlex Pro cytokine assays. Results after 72 h, the wound area in the EMVs (KMVs & MMVs) and LEMVs (LKMVs & LMMVs) treated groups showed a significant decrease in wound area and a remarkable ability to repair the wound area as compared with the control group (P < 0.0001). The percent of wound healing was almost three times more in KMVs and MMVs treated groups (57.85 % ±3.13, 69.84 % ± 4.87, respectively), and four times in LKMVs and LMMVs treated groups (80.10% ±3.50, 90.87% ±2.00, respectively) when compared to the control groups (21.74 % ± 2.389) (P < 0.0001). Furthermore, the migration rate in the presence of KMVs and MMVs (0.008810 ± 0. 0006856, 0.01085 ±0.0007964 mm2/h, respectively) and LKMVs and LMMVs (0.01470 ± 0.0009428, 0.01767 ±0.001163 mm2/h, respectively) were enhanced when compared to the control group (0. 003820 ± 0. 0003760 mm2/h). Conclusion EMVs and Loaded EMVs have a potential regenerative effect in wound healing, which promotes and enhances cell migration and proliferation, resulting in accelerated wound closure. Based on these finding, we suggest that EMVs are a novel and promising therapeutic tool for epithelial wound healing.

Committee:

Richard Simman, M.D. (Advisor); Debra Mayes, Ph.D. (Advisor); Ulas Sunar , Ph.D. (Committee Member); Terry Oroszi, Ed.D. (Committee Member)

Subjects:

Pharmacology

Keywords:

Wound Closure; Extracellular Microvesicles; Growth Factors; Wound Scratch; Cell Migration

Koya, Bharath KumarSched-ITS: An Interactive Tutoring System to Teach CPU Scheduling Concepts in an Operating Systems Course
Master of Science (MS), Wright State University, 2017, Computer Science
Operating systems is an essential course in computer science curriculum, which helps students to develop a mental model of how computer operating systems work. The internal mechanisms and processes of an operating system (OS) are often complex, non-deterministic and intangible which makes them difficult for students to understand. One such concept is central processing unit (CPU) scheduling. CPU scheduling forms the basis of the multiprogramming in an OS. In practice, OS courses involve classroom lectures describing high-level abstractions of the concepts, and students complete programming assignments to apply the material in a more concrete way. Depending on the programming assignments, this approach may leave students with only a theoretical understanding of OS ideas, which may be different from the actual way these concepts are implemented in an OS. What many students require is a practical knowledge of OS implementation to supplement the high-level presentations of concepts taught in class or presented in a textbook. To bridge the gap between the operating system theory and practical implementation, this research describes the development of an interactive simulation to present the theories involved in CPU scheduling in visualizations and simulations. This thesis discusses a prototype interactive tutoring system (ITS) named as Sched-ITS. The tool covers all the important algorithms of CPU scheduling such as first-come, first-serve (FCFS), round robin (RR), shortest job first (SJF), shortest remaining time first (SRTF), priority with pre-emption, and priority without pre-emption. Sched-ITS also provides graphical visualization of how context switches occur during CPU scheduling in a real operating system. Sched-ITS makes use of the JavaFX framework for visualization and Perf-tool for tracing an OS’s scheduling activities. It presents scheduling activities of background processes as well as pre-defined or user-defined processes. Sched-ITS can display scheduling order changes for different algorithms for the same set of processes in a Linux operating system.

Committee:

Adam R. Bryant, Ph.D. (Committee Chair); Mateen M. Rizki, Ph.D. (Committee Member); Yong Pei, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

CPU Scheduling Visualization; Linux Scheduler Visualization; Perf tool; Scheduler Trace Points; JavaFx

Ratliff-Rang, Christine AnnetteThe Hypercapnic Ventilatory Response and Behavior in Ca2+-Activated K+ (BK) Channel Knock Out Mice And T-Cell Death-Associated Gene 8 (TDAG8) Receptor Knock Out Mice
Master of Science (MS), Wright State University, 2017, Physiology and Neuroscience
Some acid sensing areas in the brain control the expression of breathing and anxiety/fear including the locus coeruleus (LC) (Redmond & Huang, 1979) and the nucleus tractus solitarius (NTS). It has been found that knocking out T-cell death-associated gene 8 (TDAG8), a chemosensor, attenuates CO2 induced fear phenotypes in mice. However their hypercapnic ventilatory response (HCVR) has not yet been looked at. Also, BK channels are large-conductance, calcium-activated potassium channels that are activated by increases in concentration of intracellular calcium ions. It has been found that BK KO rats have an increase in their HCVR (Patrone et al., 2014) however their CO2 induced anxiety/fear has not been looked at yet. In this thesis, we found that the BK channel is involved in the HCVR in mice and that the CO2 induced anxiety/fear pathway and the HCVR pathway are separate pathways in the BK and the TDAG8 mice.

Committee:

Christopher Wyatt, Ph.D. (Committee Co-Chair); Adrian Corbett, Ph.D. (Committee Co-Chair); Larry Ream, Ph.D. (Committee Member)

Subjects:

Behavioral Sciences; Biology; Biomedical Research; Neurosciences

Keywords:

Neuroscience; BK channel; TDAG8

Chunchu, Vinay KumarLayout Implementation of A 10-Bit 1.2 GS/s Digital-to-Analog Converter In 90nm CMOS
Master of Science in Electrical Engineering (MSEE), Wright State University, 2017, Electrical Engineering
Digital-to-analog converters are the interface circuits between digital and analog domains. They are used in data communication applications and different sorts of applications where transformation amongst digital and analog signals is needed. High-speed data converters are needed to match the bandwidth demands of the present-day communication systems. This thesis presents the layout implementation of a 10-bit current steering DAC with a sampling rate of about 1.2 GS/s using CMOS 90 nm technology. Current steering DAC topology is used in high-speed applications. The DAC in this thesis is designed using a segmented architecture in which 4 LSB current cells are binary weighted and 6 MSB current cells are thermometer encoded. The issues with the mixed signal layout were discussed. The schematic design does not consider the effect of parasitic resistance and capacitance whereas the layout does. The performance of the schematic and layout designs of the sub-circuits was compared. Post layout simulations of the implemented current steering DAC were performed in Cadence with 1.2 GHz clock and 55.07 MHz input signal. The simulations show that the DAC is functional and comparisons between the layout and schematic were presented.

Committee:

Saiyu Ren, Ph.D. (Advisor); Raymond E. Siferd, Ph.D. (Committee Member); Marian K. Kazimierczuk, Ph.D. (Committee Member); Yan Zhuang, Ph.D. (Committee Member)

Subjects:

Electrical Engineering

Keywords:

electrical engineering

Billa, Anka BabuDevelopment of an Ultra-Portable Non-Contact Wound Measurement System
Master of Science (MS), Wright State University, 2017, Computer Science
Continuous monitoring of changes in wound size is key to correctly predict whether wounds will heal readily with conventional treatment or require more aggressive treatment strategies. Unfortunately, existing wound measurement solutions don’t meet the clinical demand due to their limitations in accuracy, operating complexity and time, acquisition and operation cost, or reproducibility, resulting in unnecessarily lengthy recovery or extra treatment procedures, incurring an excessively high financial cost, and in many cases extended usage of addictive painkillers. In this thesis, we proposed and developed a low cost, a portable non-contact solution that combines multi-spectral imaging and a portfolio of imaging processing technologies to enable automatic and instantaneous wound identification and measurements. It provides full measurements of a wound: surface area, perimeter, length, and width, without requiring the calibration process as other existing photogrammetry or laser solutions. We have developed a prototype system that illustrates our image and wound analysis capabilities using off-shelf sensor units for capturing images. Our system is capable of identifying emulated wounds in any part of human body surface automatically and highlights them on a customized GUI instantly. Image processing engine running in background analyze and computes wound dimensions with an accuracy of 95%. Our experiment results indicated that the system is reliable, consistent, accurate and reproducible. This research has recently been selected to the 2017 I-Corps@Ohio program, a statewide program to assist faculty and graduate students from Ohio universities and colleges in validating the market potential of their technologies and assisting with launching startup companies.

Committee:

Yong Pei, Ph.D. (Advisor); Mateen Rizki, Ph.D. (Committee Member); Krishnaprasad Thirunarayan, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

Wound Dimensions Measurement; Distance between camera and object; Image Processing; Stereo Image pair Disparity; Feature based Matching

Zhang, HanshuProcessing global properties in Scene Categorization
Master of Science (MS), Wright State University, 2017, Human Factors and Industrial/Organizational Psychology MS
The current research examined the role of global properties in human observers' scene perception. In Experiment 1, comparisons of four global properties ("natural", "manmade", "open", and "closed") were collected online from a wide range of subjective choices. These answers were analyzed in a pairwise comparison model to generate four standardized reference ranking scales describing the extent to which characteristics can describe scene global properties. In Experiment 2, scene images selected from the reference scales were used to test human's performance in processing global properties conjunctively. Cognitive modeling indicated that human observers were more efficient in categorizing scene images as "natural and open" but less efficient in classifying scene images as "manmade or closed" than the predicted baseline.

Committee:

Joseph Houpt, Ph.D. (Advisor); Assaf Harel, Ph.D. (Committee Member); Scott Watamaniuk, Ph.D. (Committee Member)

Subjects:

Psychology

Keywords:

psychology

Kim, Dae WookData-Driven Network-Centric Threat Assessment
Doctor of Philosophy (PhD), Wright State University, 2017, Computer Science and Engineering PhD
As the Internet has grown increasingly popular as a communication and information sharing platform, it has given rise to two major types of Internet security threats related to two primary entities: end-users and network services. First, information leakages from networks can reveal sensitive information about end-users. Second, end-users systems can be compromised through attacks on network services, such as scanning-and-exploit attacks, spamming, drive-by downloads, and fake anti-virus software. Designing threat assessments to detect these threats is, therefore, of great importance, and a number of the detection systems have been proposed. However, these existing threat assessment systems face significant challenges in terms of i) behavioral diversity, ii) data heterogeneity, and iii) large data volume. To address the challenges of the two major threat types, this dissertation offers three unique contributions. First, we built a new system to identify network users via Domain Name System (DNS) traffic, which is one of the most important behavior-based tracking methods for addressing privacy threats. The goal of our system is to boost the effectiveness of existing user identification systems by designing effective fingerprint patterns based on semantically limited DNS queries that are missed by existing tracking efforts. Second, we built a novel system to detect fake anti-virus (AV) attacks, which represent an active trend in the distribution of Internet-based malware. Our system aims to boost the effectiveness of existing fake AV attack detection by detecting fake AV attacks in three challenging scenarios: i) fake AV webpages that require user interaction to install malware, instead of using malicious content to run automatic exploitation without users consent (e.g., shellcode); ii) fake AV webpages designed to impersonate real webpages using a few representative elements, such as the names and icons of anti-virus products from authentic anti-virus webpages; and iii) fake AV webpages that offer up-to-date solutions (e.g.,product versions and threat names) to emerging threats. Finally, we built a novel system to detect malicious online social network (OSN) accounts that participate in online promotion events. The goal of our work is to boost the effectiveness of existing detection methods, such as spammer detection and fraud detection. To achieve our goal, our framework that systematically integrates features that characterize malicious OSN accounts based on three of their characteristics: their general behaviors, their recharging patterns, and their currency usage, and then leverages statistical classifier for detection.

Committee:

Junjie Zhang, Ph.D. (Advisor); Adam Robert Bryant, Ph.D. (Committee Member); Bin Wang, Ph.D. (Committee Member); Xuetao Wei, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

network security; fake anti-virus software; intrusion detection; web document analysis; statistical classification; Domain Name System; behavioral fingerprints; privacy; online social networks; virtual currency; malicious accounts

Kasrani, ImenDevelopment of a Performance Assessment System for Language Learning
Master of Science (MS), Wright State University, 2017, Computer Science
Recent advances in computer-assisted, language-speaking, learning/training technology have demonstrated its promising potential to improve the outcome of language learning in early education, special education, English as a Second Language (ESL), and foreign language. The growing number of readily available mobile app-based solutions help encourage interest in learning to speak a foreign language, but their effectiveness is limited due to their lack of objective assessment and performance feedback resembling expert judgment. For example, it has been recognized that, in early education, students learn best with one-on-one instructions. Unfortunately, teachers do not have the time, and it is challenging to extend the learning to the home without the assistance of an independent learning/training tool. In this thesis research, our objective is to develop an effective and practical solution that will help people to learn and practice a new language independently at low cost. We have explored the use of real-time speech recognition, language translation, text synthesis, artificial intelligence (AI), and language intelligibility assessment technologies to develop a learning/training system that provides automatic assessment and instantaneous feedback of language-speaking performance in order to achieve an independent-learning workflow. Furthermore, we have designed and implemented a successful prototype system that demonstrates the feasibility and effectiveness of such a computer-assisted independent learning/training solution. This prototype can be easily used on a computer, tablet, smartphone, and other portable devices, and provides a new learning experience that is augmented and enhanced by objective assessment and significant feedback in order to improve the language-speaking proficiency of its user. Additionally, it may be used for real-time translation to support conversation across different languages. Our experimental results demonstrate that the proposed system can sufficiently analyze the intelligibility of one’s speaking, accurately identify mispronounced words, and define a feedback that localizes and highlights errors for continuous practice toward perfection.

Committee:

Yong Pei, Ph.D. (Advisor); Mateen Rizki, Ph.D. (Committee Member); Paul Bender, Ph.D. (Committee Member); Anna Lyon, Ed.D. (Committee Member)

Subjects:

Computer Science

Keywords:

Performance Assessment; Language Learning; Speech Recognition

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