View All Items

Title: Numerical Study of Interfacial flow using Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) Method.
Creator: Haghshenas, Majid, Kumar, Ranganathan, Das, Tuhin, Ahmed, Kareem, Shivamoggi, Bhimsen, University of Central Florida
Abstract / Description: Solving interfacial flows numerically has been a challenge due to the lack of sharpness and the presence of spurious currents at the interface. Two methods, Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) method and Ghost Fluid Method (GFM) have been developed in the finite volume framework and employed in several interfacial flows such as Rayleigh-Taylor instability, rising bubble, impinging droplet and cross-flow oil plume. In the static droplet simulation, A-CLSVOF substantially...
Show moreSolving interfacial flows numerically has been a challenge due to the lack of sharpness and the presence of spurious currents at the interface. Two methods, Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) method and Ghost Fluid Method (GFM) have been developed in the finite volume framework and employed in several interfacial flows such as Rayleigh-Taylor instability, rising bubble, impinging droplet and cross-flow oil plume. In the static droplet simulation, A-CLSVOF substantially reduces the spurious currents. The capillary wave relaxation shows that this method delivers results comparable to those of more rigorous methods such as Front Tracking methods for fine grids. The results for the other interfacial flows also compared well with the experimental results. Next, interfacial forces are implemented by enlisting the finite volume discretization of Ghost Fluid Method. To assess the A-CLSVOF/GFM performance, four cases are studied. In the case of the static droplet in suspension, the combined A-CLSVOF/GFM produces a sharp and accurate pressure jump compared to the traditional CSF (continuum surface force) implementation. For the linear two-layer shear flow, GFM sharp treatment of the viscosity captured the velocity gradient across the interface. For a gaseous bubble rising in a viscous fluid, GFM outperforms CSF by almost 10%. Also, a Decoupled Pressure A-CLSVOF/GFM method (DPM) has been developed which separates pressure into two pressure components, one accounting for interfacial forces such as surface tension and another representing the rest of flow pressure. It is proven that the DPM implementation results in more efficiency in PISO (Pressure Implicit with Splitting of Operators) loop. A two-phase solver is used to study buoyant oil discharge in quiescent and cross-flow ambient. Different modes of breakup including dripping, jetting (axisymmetric and asymmetric) and atomization for cross-flow oil jet are captured.
Show less
Date Issued: 2018
Identifier: CFE0007570, ucf:52582
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007570

Title: Analysis of Dialog Surrounding Animal Testing in Vaccine Research.
Creator: Johnson, Natalie, Scott, Blake, Rounsaville, Angela, Wheeler, Stephanie, University of Central Florida
Abstract / Description: This study analyzed the scholarly discussions surrounding the topic of animal testing for vaccine potency and safety in humans. The primary stakeholders in this discussion are the scientists, medical professionals, and researchers who are involved in animal models and alternative testing methods, specifically related to vaccine development. The debate among these professionals regarding alternative methods, which encompasses any testing approach that does not involve animals, has been...
Show moreThis study analyzed the scholarly discussions surrounding the topic of animal testing for vaccine potency and safety in humans. The primary stakeholders in this discussion are the scientists, medical professionals, and researchers who are involved in animal models and alternative testing methods, specifically related to vaccine development. The debate among these professionals regarding alternative methods, which encompasses any testing approach that does not involve animals, has been analyzed. This project looks at the argument from a historical perspective, which provides background context for the current debate and an understanding of how the current arguments originated. The changing mindset over time of using animals has been explored, as well as conversations and arguments about alternative methods.Research questions and prior questions consider the conversation's historical influences on this present day debate and are answered in this analysis. Persuasive language has been looked at, with a consideration of how it is used both within and outside the research community, as well as the influences the various stakeholders have on one another. The burgeoning field of the rhetoric of health and medicine provides a forum and a community of scholars for a rhetorical analysis such as this one to be discussed and the findings considered for other rhetorical studies. This research design project provides a comprehensive rhetorical analysis that uses the topoi theory and a textual-intertextual analysis as a framework, along with detailed coding of the texts. This project shows the advantages of a combined rhetorical approach that leads to understanding a debate through identifying multiple layers of argument. The findings and its implications for those within rhetoric, the scholarly community, as well as the scientific field are discussed in the final chapter.
Show less
Date Issued: 2017
Identifier: CFE0006609, ucf:51288
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006609

Title: A Delphi Study to Construct a Script Concordance Test for Spiritual and Religious Competence in Counseling.
Creator: Christmas, Christopher, Young, Mark, Hagedorn, William, Bai, Haiyan, Carson, David, University of Central Florida
Abstract / Description: The need to address spiritual and religious issues is well established in the counseling literature and in accreditation standards, however, many graduates counseling students do not feel prepared to address these issues. In the United States, the vast majority of clients consider themselves to be spiritual or religious, so counselors who lack competence in addressing spiritual and religious issues in counseling are likely to offer ineffective or perhaps unethical care to clients. Counselor...
Show moreThe need to address spiritual and religious issues is well established in the counseling literature and in accreditation standards, however, many graduates counseling students do not feel prepared to address these issues. In the United States, the vast majority of clients consider themselves to be spiritual or religious, so counselors who lack competence in addressing spiritual and religious issues in counseling are likely to offer ineffective or perhaps unethical care to clients. Counselor educators must improve education and assessment in this critical specialty area of counseling. Of primary concern is a student's ability to demonstrate spiritual competence in counseling. The 2009 ASERVIC Spiritual Competencies offer the most comprehensive standard of spiritual competence in counseling in any mental health profession, however there is no reliable and standardized assessment that measures demonstrated spiritual competency. Competency can best be measured when the examinee makes choices in a context that is similar or the same as that in which he or she will practice, therefore an effective competency measurement must include client cases. The purpose of this study was to investigate whether a case based assessment for measuring clinical judgment in situations of uncertainty, called a Script Concordance Test, could be constructed by experts using the Delphi Method. This instrument was based on the 2009 ASERVIC Spiritual Competencies as the standard for demonstrated competence. The results of this study indicated that expert practitioners and educators could come to consensus on appropriate cases, appropriate competencies to measure in each case, items to assess competency in each case, and an instrument that included items assessing all 14 of the 2009 Spiritual Competencies. Additionally, the constructed instrument demonstrated excellent test retest reliability and adequate internal reliability.There are several implications for counselor education. First, this study provides evidence that expert practitioners and educators can come to consensus to construct a highly contextual instrument to measures clinical decision making about spiritual competence in counseling. Second, a promising new type of instrument with excellent reliability and strong content validity has been introduced to the field of counselor education. Third, with appropriate assessment, counselor education programs can begin to measure student competence, in terms of clinical judgment, on addressing spiritual and religions issues in counseling over time because this instrument is appropriate for use at different intervals throughout professional development. Fourth, the format of this instrument is also useful for educational purposes and reflective practice. Finally, the theoretical foundations of the Delphi Method and script concordance tests are compatible with one another and with instrument development. The researcher recommends that future studies to construct script concordance tests for other specialty areas of competence employ and refine this method.
Show less
Date Issued: 2013
Identifier: CFE0005149, ucf:50695
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005149

Title: A Generic Framework For Multi-Method Modeling and Simulation of Complex Systems Using Discrete Event, System Dynamics and Agent Based Approaches.
Creator: Mykoniatis, Konstantinos, Karwowski, Waldemar, Kincaid, John, Xanthopoulos, Petros, Akbas, Ilhan, University of Central Florida
Abstract / Description: Decisions about Modeling and Simulation (M(&)S) of Complex Systems (CS) need to be evaluated prior to implementation. Discrete Event (DE), System Dynamics (SD), and Agent Based (AB) are three different M(&)S approaches widely applied to enhance decision-making of complex systems. However, single type M(&)S approaches can face serious challenges in representing the overall multidimensional nature of CS and may result in the design of oversimplified models excluding important factors....
Show moreDecisions about Modeling and Simulation (M(&)S) of Complex Systems (CS) need to be evaluated prior to implementation. Discrete Event (DE), System Dynamics (SD), and Agent Based (AB) are three different M(&)S approaches widely applied to enhance decision-making of complex systems. However, single type M(&)S approaches can face serious challenges in representing the overall multidimensional nature of CS and may result in the design of oversimplified models excluding important factors. Conceptual frameworks are necessary to offer useful guidance for combining and/or integrating different M(&)S approaches. Although several hybrid M(&)S frameworks have been described and are currently deployed, there is limited guidance on when, why and how to combine, and/or integrate DE, SD, and AB approaches. The existing hybrid frameworks focus more on how to deal with specific problems rather than to provide a generic way of applicability to various problem situations.The main aim of this research is to develop a generic framework for Multi-Method Modeling and Simulation of CS, which provides a practical guideline to integrated deployment or combination of DE, SD, and AB M(&)S methods. The key contributions of this dissertation include: (1) a meta-analysis literature review that identifies criteria and generic types of interaction relationships that are served as a basis for the development of a multi-method modeling and simulation framework; (2) a methodology and a framework that guide the user through the development of multi-method simulation models to solve CS problems; (3) an algorithm that recommends appropriate M(&)S method(s) based on the user selected criteria for user defined objective(s); (4) the implementation and evaluation of multi method simulation models based on the framework's recommendation in diverse domains; and (5) the comparison of multi-method simulation models created by following the multi-method modeling and simulation framework.It is anticipated that this research will inspire and motivate students, researchers, practitioners and decision makers engaged in M(&)S to become aware of the benefits of the cross-fertilization of the three key M(&)S methods.
Show less
Date Issued: 2015
Identifier: CFE0005980, ucf:50762
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005980

Title: An Unsupervised Consensus Control Chart Pattern Recognition Framework.
Creator: Haghtalab, Siavash, Xanthopoulos, Petros, Pazour, Jennifer, Rabelo, Luis, University of Central Florida
Abstract / Description: Early identification and detection of abnormal time series patterns is vital for a number of manufacturing.Slide shifts and alterations of time series patterns might be indicative of some anomalyin the production process, such as machinery malfunction. Usually due to the continuous flow of data monitoring of manufacturing processes requires automated Control Chart Pattern Recognition(CCPR) algorithms. The majority of CCPR literature consists of supervised classification algorithms. Less...
Show moreEarly identification and detection of abnormal time series patterns is vital for a number of manufacturing.Slide shifts and alterations of time series patterns might be indicative of some anomalyin the production process, such as machinery malfunction. Usually due to the continuous flow of data monitoring of manufacturing processes requires automated Control Chart Pattern Recognition(CCPR) algorithms. The majority of CCPR literature consists of supervised classification algorithms. Less studies consider unsupervised versions of the problem. Despite the profound advantageof unsupervised methodology for less manual data labeling their use is limited due to thefact that their performance is not robust enough for practical purposes. In this study we propose the use of a consensus clustering framework. Computational results show robust behavior compared to individual clustering algorithms.
Show less
Date Issued: 2014
Identifier: CFE0005178, ucf:50670
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005178

Title: Structure-preserving finite difference methods for linearly damped differential equations.
Creator: Bhatt, Ashish, Moore, Brian, Choudhury, Sudipto, Gurel, Basak, Kauffman, Jeffrey L., University of Central Florida
Abstract / Description: Differential equations (DEs) model a variety of physical phenomena in science and engineering. Many physical phenomena involve conservative or dissipative forces, which manifest themselves as qualitative properties of DEs that govern these phenomena. Since only a few and simplistic models are known to have exact solutions, approximate solution techniques, such as numerical integration, are used to reveal important insights about solution behavior and properties of these models. Numerical...
Show moreDifferential equations (DEs) model a variety of physical phenomena in science and engineering. Many physical phenomena involve conservative or dissipative forces, which manifest themselves as qualitative properties of DEs that govern these phenomena. Since only a few and simplistic models are known to have exact solutions, approximate solution techniques, such as numerical integration, are used to reveal important insights about solution behavior and properties of these models. Numerical integrators generally result in undesirable quantitative and qualitative errors . Standard numerical integrators aim to reduce quantitative errors, whereas geometric (numerical) integrators aim to reduce or eliminate qualitative errors, as well, in order to improve the accuracy of numerical solutions. It is now widely recognized that geometric (or structure-preserving) integrators are advantageous compared to non-geometric integrators for DEs, especially for long time integration.Geometric integrators for conservative DEs have been proposed, analyzed, and investigated extensively in the literature. The motif of this thesis is to extend the idea of structure preservation to linearly damped DEs. More specifically, we develop, analyze, and implement geometric integrators for linearly damped ordinary and partial differential equations (ODEs and PDEs) that possess conformal invariants, which are qualitative properties that decay exponentially along any solution of the DE as the system evolves over time. In particular, we derive restrictions on the coefficient functions of exponential Runge-Kutta (ERK) numerical methods for preservation of certain conformal invariants of linearly damped ODEs. An important class of these methods is shown to preserve the damping rate of solutions of damped linear ODEs. Linearly stability and order of accuracy for some specific cases of ERK methods are investigated. Geometric integrators for PDEs are designed using structure-preserving ERK methods in space, time, or both. These integrators for PDEs are also shown to preserve additional structure in certain special cases. Numerical experiments illustrate higher order accuracy and structure preservation properties of various ERK based methods, demonstrating clear advantages over non-structure-preserving methods, as well as usefulness for solving a wide range of DEs.
Show less
Date Issued: 2016
Identifier: CFE0006832, ucf:51763
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006832

Title: Buidling Lax Integrable Variable-Coefficient Generalizations to Integrable PDEs and Exact Solutions to Nonlinear PDEs.
Creator: Russo, Matthew, Choudhury, Sudipto, Moore, Brian, Schober, Constance, Christodoulides, Demetrios, University of Central Florida
Abstract / Description: This dissertation is composed of two parts. In Part I a technique based on extended Lax Pairs isfirst considered to derive variable-coefficient generalizations of various Lax-integrable NLPDE hierarchies recently introduced in the literature. It is demonstrated that the technique yields Lax- or S-integrable nonlinear partial differential equations (PDEs) with both time- and space-dependent coefficients which are thus more general than almost all cases considered earlier via other methods such...
Show moreThis dissertation is composed of two parts. In Part I a technique based on extended Lax Pairs isfirst considered to derive variable-coefficient generalizations of various Lax-integrable NLPDE hierarchies recently introduced in the literature. It is demonstrated that the technique yields Lax- or S-integrable nonlinear partial differential equations (PDEs) with both time- and space-dependent coefficients which are thus more general than almost all cases considered earlier via other methods such as the Painleve Test, Bell Polynomials, and various similarity methods. However, this technique, although operationally effective, has the significant disadvantage that, for any integrable system with spatiotemporally varying coefficients, one must 'guess' a generalization of the structure of the known Lax Pair for the corresponding system with constant coefficients. Motivated by the somewhat arbitrary nature of the above procedure, we present a generalization to the well known Estabrook-Wahlquist prolongation technique which provides a systematic procedure for the derivation of the Lax representation. In order to obtain a nontrivial Lax representation we must impose differential constraints on the variable coefficients present in the nlpde. The resulting constraints determine a class of equations which represent generalizations to a previously known integrable constant coefficient nlpde. We demonstrate the effectiveness of this technique by deriving variable-coefficient generalizations to the nonlinear Schrodinger (NLS) equation, derivative NLS equation, PT-symmetric NLS, fifth-order KdV, and three equations in the MKdV hierarchy. In Part II of this dissertation, we introduce three types of singular manifold methods which have been successfully used in the literature to derive exact solutions to many nonlinear PDEs extending over a wide range of applications. The singular manifold methods considered are: truncated Painleve analysis, Invariant Painleve analysis, and a generalized Hirota expansion method. We then consider the KdV and KP-II equations as instructive examples before using each method to derive nontrivial solutions to a microstructure PDE and two generalized Pochhammer-Chree equations.
Show less
Date Issued: 2016
Identifier: CFE0006173, ucf:51144
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006173

Title: Synthesis and Characterization of Core-Shell Zinc Silica Nanoparticles and Zinc Silica Nanogels for Agricultural Applications.
Creator: Berroth, Megan, Santra, Swadeshmukul, Moore, Sean, Jewett, Travis, University of Central Florida
Abstract / Description: Plant pathogens are a serious problem facing the agricultural industry today. Current methodologies use copper based biocides as the main form of defense. Unfortunately this can lead to damaging environmental effects and increased rates of antimicrobial resistance. In this study, antimicrobial activity of multiple alternative zinc-based nanoformulations were tested against three important plant pathogens: Xanthomonas alfalfae, Pseudomonas syringae, and Clavobacter michiganensis. Xanthomonas...
Show morePlant pathogens are a serious problem facing the agricultural industry today. Current methodologies use copper based biocides as the main form of defense. Unfortunately this can lead to damaging environmental effects and increased rates of antimicrobial resistance. In this study, antimicrobial activity of multiple alternative zinc-based nanoformulations were tested against three important plant pathogens: Xanthomonas alfalfae, Pseudomonas syringae, and Clavobacter michiganensis. Xanthomonas sub species cause Citrus canker, a devastating disease that affects millions of citrus trees worldwide while the latter two affect tomato crops. Materials synthesis was completed and the resulting nanoformulations were characterized by Atomic Absorption Spectroscopy, Scanning Electron Microscopy, High Resolution Transmission Electron Microscopy, and X-Ray Photoelectron Spectroscopy. The antimicrobial efficacy of the newly synthesized formulas and two commercially available products, Kocide 3000 (DuPont) and Nordox (Brandt), were determined by Minimum Inhibitory Concentration Assays followed by Bacterial Viability Assays. The subsequent data demonstrated a marketed difference in the way the antimicrobial agents acted upon the bacterial species. The core-shell zinc silica nanoparticles (C-SZnSiNP) proved to be ineffective, while the zinc silica nanogel (ZnSiNG) was as successful at killing the bacteria as the commercial products. This shows promise for a new alternative material with zinc at the forefront of the fight against plant pathogens.
Show less
Date Issued: 2015
Identifier: CFE0006209, ucf:51099
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006209

Title: Implementation of Refining Statements in OpenJML and Verification of Higher Order Methods with Model Program Specifications.
Creator: Gurramkonda, Sai Chandesh, Leavens, Gary, Turgut, Damla, Jha, Sumit Kumar, University of Central Florida
Abstract / Description: The Java Modeling Language (JML) describes the functional behavior of Java classes and methods using pre- and postconditions. However, standard pre- and postcondition specifications cannot verify calls to higher order methods (HOMs). JML uses model program specifications to reason about HOMs. This thesis describes the implementation of model programs in the OpenJML tool. The implementation includes parsing, type checking, and matching of model program specifications against the code.
Date Issued: 2017
Identifier: CFE0006743, ucf:51831
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006743

Title: Bio-inspired, Varying Manifold Based Method with Enhanced Initial Guess Strategies for Single Vehicle's Optimal Trajectory Planning.
Creator: Li, Ni, Xu, Yunjun, Lin, Kuo-Chi, Bai, Yuanli, Behal, Aman, University of Central Florida
Abstract / Description: Trajectory planning is important in many applications involving unmanned aerial vehicles, underwater vehicles, spacecraft, and industrial manipulators. It is still a challenging task to rapidly find an optimal trajectory while taking into account dynamic and environmental constraints. In this dissertation, a unified, varying manifold based optimal trajectory planning method inspired by several predator-prey relationships is investigated to tackle this challenging problem. Biological species,...
Show moreTrajectory planning is important in many applications involving unmanned aerial vehicles, underwater vehicles, spacecraft, and industrial manipulators. It is still a challenging task to rapidly find an optimal trajectory while taking into account dynamic and environmental constraints. In this dissertation, a unified, varying manifold based optimal trajectory planning method inspired by several predator-prey relationships is investigated to tackle this challenging problem. Biological species, such as hoverflies, ants, and bats, have developed many efficient hunting strategies. It is hypothesized that these types of predators only move along paths in a carefully selected manifold based on the prey's motion in some of their hunting activities. Inspired by these studies, the predator-prey relationships are organized into a unified form and incorporated into the trajectory optimization formulation, which can reduce the computational cost in solving nonlinear constrained optimal trajectory planning problems. Specifically, three motion strategies are studied in this dissertation: motion camouflage, constant absolute target direction, and local pursuit. Necessary conditions based on the speed and obstacle avoidance constraints are derived. Strategies to tune initial guesses are proposed based on these necessary conditions to enhance the convergence rate and reduce the computational cost of the motion camouflage inspired strategy. The following simulations have been conducted to show the advantages of the proposed methods: a supersonic aircraft minimum-time-to-climb problem, a ground robot obstacle avoidance problem, and a micro air vehicle minimum time trajectory problem. The results show that the proposed methods can find the optimal solution with higher success rate and faster convergent speed as compared with some other popular methods. Among these three motion strategies, the method based on the local pursuit strategy has a relatively higher success rate when compared to the other two.In addition, the optimal trajectory planning method is embedded into a receding horizon framework with unknown parameters updated in each planning horizon using an Extended Kalman Filter.
Show less
Date Issued: 2013
Identifier: CFE0005023, ucf:49986
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005023

Title: Numerical Simulations for the Flow of Rocket Exhaust Through a Granular Medium.
Creator: Kraakmo, Kristina, Moore, Brian, Brennan, Joseph, Rollins, David, University of Central Florida
Abstract / Description: Physical lab experiments have shown that the pressure caused by an impinging jet on a granular bed has the potential to form craters. This poses a danger to landing success and nearby spacecraft for future rocket missions. Current numerical simulations for this process do not accurately reproduce experimental results. Our goal is to produce improved simulations to more accurately and efficiently model the changes in pressure as gas flows through a porous medium. A two-dimensional model in...
Show morePhysical lab experiments have shown that the pressure caused by an impinging jet on a granular bed has the potential to form craters. This poses a danger to landing success and nearby spacecraft for future rocket missions. Current numerical simulations for this process do not accurately reproduce experimental results. Our goal is to produce improved simulations to more accurately and efficiently model the changes in pressure as gas flows through a porous medium. A two-dimensional model in space known as the nonlinear Porous Medium Equation as it is derived from Darcy's law is used. An Alternating-Direction Implicit (ADI) temporal scheme is presented and implemented which reduces our multidimensional problem into a series of one-dimensional problems. We take advantage of explicit approximations for the nonlinear terms using extrapolation formulas derived from Taylor-series, which increases efficiency when compared to other common methods. We couple our ADI temporal scheme with different spatial discretizations including a second-order Finite Difference (FD) method, a fourth-order Orthogonal Spline Collocation (OSC) method, and an Nth-order Chebyshev Spectral method. Accuracy and runtime are compared among the three methods for comparison in a linear analogue of our problem. We see the best results for accuracy when using an ADI-Spectral method in the linear case, but discuss possibilities for increased efficiency using an ADI-OSC scheme. Nonlinear results are presented using the ADI-Spectral method and the ADI-FD method.
Show less
Date Issued: 2013
Identifier: CFE0005017, ucf:49998
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005017

Title: PATCHWORK CULTURE: QUILT TACTICS AND DIGITEXTUALITY.
Creator: Barrett Ferrier, Michelle, Saper, Craig, University of Central Florida
Abstract / Description: Embedded in the quilt top, the fabric patches are relays, time pathways to stories and memories of their former owners. Through the quilts, the voices of the past survive. The stories trace a path of connection between oral traditions, storytelling, the invention of meaning, and the preservation of cultural memory. The theory and method described herein use the quilt patchwork metaphor as the basis for a web interface for designing and modeling knowledge-based graphical, narrative, and...
Show moreEmbedded in the quilt top, the fabric patches are relays, time pathways to stories and memories of their former owners. Through the quilts, the voices of the past survive. The stories trace a path of connection between oral traditions, storytelling, the invention of meaning, and the preservation of cultural memory. The theory and method described herein use the quilt patchwork metaphor as the basis for a web interface for designing and modeling knowledge-based graphical, narrative, and multimedia data. More specifically, the method comprises a digital storytelling and knowledge management tool that allows one or more users to create, save, store, and visually map or model digital stories. The method creates a digital network of a community's stories for digital ethnography work. Digital patches that represent the gateway to the stories of an individual are pieced together into a larger quilt design, creating a visual space that yields the voices of its creators at the click of a mouse. Through this narrative mapping, users are able to deal with complexity, ambiguity, density, and information overload. The method takes the traditional quilt use and appropriates it into a digital apparatus so that the user is connected to multiple points of view that can be dynamically tried out and compared. The hypertextual quilting method fulfills the definition of a deconstructive hypertext and emancipatory social science research methodologies by creating a collaborative, polyvocal interface where users have access to the code, content and conduits to rewrite culture's history with subaltern voices. In this digital place of intertextuality, stories are juxtaposed with images in a montage that denies the authority of a single voice and refuses fixed meaning. In dialogue, contestation, and play, the digitextuality of the Digital Story Quilt provides a praxis for critical theory. The Digital Story Quilt method concerns itself with questions of identity, the processes through which these identities are developed, the mechanics of processes of privilege and marginalization and the possibility of political action through narrative performance against these processes.
Show less
Date Issued: 2007
Identifier: CFE0001659, ucf:47239
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001659

Title: THE NATURE OF AND IMPORTANCE OF ART CRITICISM AND ITS EDUCATIONAL APPLICATIONS IN K-12 CLASSROOMS.
Creator: Blackmon, Tia, Brewer, Thomas, University of Central Florida
Abstract / Description: This thesis will critically examine the importance, purpose, methods, and applications of art criticism. Initial background information on types of critical judgment will lay the foundation to understanding the different methods of art criticism. While the articles and journals read on criticism vary in style and method they all have the goal to become a basic framework for examining the form and content of works of art. My goal of this thesis will be to take researched methods of criticism...
Show moreThis thesis will critically examine the importance, purpose, methods, and applications of art criticism. Initial background information on types of critical judgment will lay the foundation to understanding the different methods of art criticism. While the articles and journals read on criticism vary in style and method they all have the goal to become a basic framework for examining the form and content of works of art. My goal of this thesis will be to take researched methods of criticism and create my own methods of criticism to be used in the K-12 art education classroom. The body of my research will examine the following methods of criticism (1) Feldman Method, (2) Broudy Method, (3) Lankford Method, (4) Anderson Method, (5) Feminist Conversation Method, (6) Modernism, and (7) Postmodernism. My research will seek to understand the nature of and importance of art criticism and its educational applications for K-12 art classrooms. In conjunction with the examination of these methods and their corresponding stages, I will be able to synthesize three methods of criticism to be used in the classroom: formalist, expressivist, and instrumentalist.
Show less
Date Issued: 2015
Identifier: CFH0004863, ucf:45465
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004863

Title: Multi-scale fluid-structure interaction model analysis of patient-specific geometry for optimization of lvad outflow graft implantation: an investigation aimed at reducing stroke risk.
Creator: Prather, Ray, Kassab, Alain, Mansy, Hansen, Bai, Yuanli, Divo, Eduardo, DeCampli, William, University of Central Florida
Abstract / Description: A Left Ventricular Assist Device (LVAD), is a mechanical pump capable of(&)nbsp;providing circulatory myocardium relief when used as bridge-to-transplantation by reducing the workload of a failing heart, with the additional bonus of allowing for cardiac recovery when used as destination therapy. The newer generations of continuous flow VADs are essentially axial or radial flow pumps, and while these devices are capable their efficiency depends upon fluid composition and flow field patterns....
Show moreA Left Ventricular Assist Device (LVAD), is a mechanical pump capable of(&)nbsp;providing circulatory myocardium relief when used as bridge-to-transplantation by reducing the workload of a failing heart, with the additional bonus of allowing for cardiac recovery when used as destination therapy. The newer generations of continuous flow VADs are essentially axial or radial flow pumps, and while these devices are capable their efficiency depends upon fluid composition and flow field patterns. The most devastating complication of VAD therapy is caused by embolization of thrombi formed within the LVAD or inside the heart into the brain leading to stroke. Anticoagulation management and improved LVADs design has reduced stroke incidence, however, investigators have recently reported the incidence of thromboembolic cerebral events is still significant and ranges from 14% to 47% over a period of 6-12 months. Blood clots may cause obstruction of critical vessels, such as cerebral arteries, reducing brain oxygenation and resulting in devastating consequences like major neurocognitive malfunction and complications which can be fatal.The hypothesis that incidence of stroke can be significantly reduced by adjusting the VAD outflow cannula implantation to direct dislodged thrombi away from the cerebral vessels has been recently supported by a series of steady flow computations assuming rigid vessel walls for the vasculature. Such studies have shown as much as a 50% reduction in embolization rates depending on outflow cannula implantation. In this study, a pulsatile fully compliant vessel wall model is developed to further establish this hypothesis. A time-dependent multi-scale Eulerian Computational Fluid Dynamics (CFD) analysis of patient-specific geometry models of the VAD-bed vasculature is coupled with a 3D Finite Element Analysis (FEA) of the mechanical response of the vascular walls to establish the VAD assisted hemodynamics. A Lagrangian particle tracking algorithm is used to determine the embolization rates of thrombi emanating from the cannula or other possible thrombogenic locations such as the aortic root. This multiscale Eulerian-Lagrangian pulsatile fluid-structure coupled paradigm allows for a fully realistic model of the hemodynamics of interest. The patient-specific geometries obtained from CT scan are implemented into the numerical domain in two modes. In the 3D CFD portion of the problem, the geometry accounts solely for the flow volume where the fluid is modelled as constant density and non-Newtonian under laminar pulsatile flow conditions. The blood-thrombus ensemble in treated as a two-phase flow, handled by an Eulerian-Lagrangian coupled scheme to solve the flow field and track particle transport. Thrombi are modelled as constant density spherical particles. Particle interactions are limited to particle-to-wall and particle-to-fluid, while particle-to-particle interaction are neglected for statistical purposes. On the other hand, with the help of Computer Aided Design (CAD) software a patient-specific aortic wall geometry with variable wall thickness is brought into the numerical domain. FEA is applied to determine the aortic wall cyclic displacement under hydrodynamic loads. To properly account for wall deformation, the arterial wall tissue incorporates a hyperelastic material model based on the anisotropic Holzapfel model for arteries. This paradigm is referred to as Fluid Structure Interaction (FSI) and allows structural analysis in conjunction with flow investigation to further monitor pathological flow patterns. The FSI model is driven by time dependent flow and pressure boundary conditions imposed at the boundaries of the 3D computational domain through a 50 degree of freedom 0D lumped parameter model (LPM) electric circuit analog of the peripheral VAD-assisted circulation.Results are presented for a simple vessel model of the ascending aorta to validate the anisotropic fiber orientation implementation. Arterial wall dilation is measured between 5-20% in the range reported in literature. Hemodynamics of the VAD assisted flow in a patient-derived geometry computed using rigid vessels walls are compared to those for a linearly elastic vessel wall model and a hyperelastic anisotropic vessel wall model. Moreover, the thromboembolization rates are presented and compared for pulsatile hemodynamics in rigid and compliant wall models. Pulsatile flow solutions for embolization probabilities corroborate the hypothesis that tailoring the LVAD cannula implantation configuration can significantly reduce thromboembolization rates, and this is consistent with indications from previous steady-flow calculations.
Show less
Date Issued: 2018
Identifier: CFE0007077, ucf:52017
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007077

Title: Assessing the effectiveness of online focus groups versus in-person focus groups.
Creator: Richard, Brendan, Sivo, Stephen, Boote, David, Witta, Eleanor, Ford, Robert, Murphy, Jamie, University of Central Florida
Abstract / Description: Increasingly researchers are turning to online focus groups as a qualitative research method, yet rigorous methodological studies regarding the quantity, quality and diversity of the data generated relative to traditional in-person focus groups are limited. This study experimentally tests the idea generation capabilities of online text-based focus groups versus traditional in-person focus groups using sustainability in the hospitality industry as the idea generation topic. Participants were...
Show moreIncreasingly researchers are turning to online focus groups as a qualitative research method, yet rigorous methodological studies regarding the quantity, quality and diversity of the data generated relative to traditional in-person focus groups are limited. This study experimentally tests the idea generation capabilities of online text-based focus groups versus traditional in-person focus groups using sustainability in the hospitality industry as the idea generation topic. Participants were purposively sampled from the hospitality program at a large Southeastern university and randomly assigned into one of two treatment groups: online text-based or traditional in-person focus groups. The in-person focus groups resulted in a larger word count, and a higher number of ideas generated, although both in-person and online generated an equivalent number of unique ideas. The online focus group generated a comparable average quality of ideas and number of good ideas. There was a high degree of overlap in themes generated by both groups. The results show that online focus groups are capable of generating a comparable level of idea quantity, quality and diversity relative to in-person focus groups.
Show less
Date Issued: 2018
Identifier: CFE0007086, ucf:51945
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007086

Title: A hermeneutic study of secondary English Language Arts teacher candidates' writing instruction experiences in ESOL methods courses.
Creator: Bello, Paula, Olan, Elsie, Nutta, Joyce, Hopp, Carolyn, Mihai, Florin, University of Central Florida
Abstract / Description: The purpose of this hermeneutic study was to understand, describe and interpret secondary English Language Arts (ELA) teacher candidates'(TC) experiences with writing instruction while attending English for Speakers of Other Languages (ESOL) methods courses. The study included a purposeful convenience sample of 15 (fifteen) secondary ELA teacher candidates' (TC) attending 4 (four) different sections in 2 (two) ESOL methods courses. TCs were invited to participate in inquiry driven activities...
Show moreThe purpose of this hermeneutic study was to understand, describe and interpret secondary English Language Arts (ELA) teacher candidates'(TC) experiences with writing instruction while attending English for Speakers of Other Languages (ESOL) methods courses. The study included a purposeful convenience sample of 15 (fifteen) secondary ELA teacher candidates' (TC) attending 4 (four) different sections in 2 (two) ESOL methods courses. TCs were invited to participate in inquiry driven activities including written reflections in response to a literacy questionnaire, oral interviews responding to open-ended questions and focus/work groups' discussions, which allowed them to reflect about their past and present literacy and learning experiences and become reflexive about the application of knowledge and practices in their future classrooms. The phenomenological hermeneutic qualitative design granted the researcher insight into participants' literacy and learning experiences as lived in relationship with their contexts, in a specific place and time.Colaizzi's (1978) seven-stages data analysis procedure, enabled the analysis and thorough description of TCs' experiences with writing instruction along their schooling and teacher education career. The following thematic categorization of participants' experiences was outlined: a)- TCs' experiences with instruction received and knowledge developed in teacher education programs, b)- TCs' recognition of good and bad practices in educational settings, including planning accommodations in general education classrooms, c)- TCs' experiences with ELs in authentic settings, d)- TCs' awareness process of ELs in schools, and e)- TCs' experiences with and about writing instruction to teach ELs.Further in depth data analysis guided the researcher into the interpretation of the fundamental structure of the phenomenon of teacher education experiences with writing instruction. TCs' experiences, drawn from different learning settings (including methods and content courses and field practicum), were articulated thanks to their participation in inquiry based learning activities. This breath of experiences specifically informed TCs' writing instruction experiences while attending ESOL methods courses. TCs' reflective and reflexive stances position them at the center of the educational phenomenon, in which TCs develop from facilitators of classroom communication to facilitators of learning processes and intercultural mediators.The phenomenon of TCs' lived experiences with writing instruction while attending ESOL methods courses, and by extension, content area courses and field practicum, needs to be analyzed, described and interpreted in order to develop practices conducive to inform the curricular development of teacher education programs and courses, to better prepare TCs to teach every learner develop knowledge and literacy, paying special attention to ELs'proficiency in English as a second language (ESL).?
Show less
Date Issued: 2016
Identifier: CFE0006681, ucf:51904
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006681

Title: Predicting Gun Ownership in America: Birth Cohort, Political Views, and Attitudes Towards Gun Control Legislation.
Creator: Adams, Jared, Gay, David, Donley, Amy, Corzine, Harold, University of Central Florida
Abstract / Description: With mass shootings occurring with frightening regularity, research into gun ownership behavior is becoming increasingly important for public policy creation and public safety. While extant research tells us that firearm ownership is woven deep into the historical fabric of American culture, scholarship has yet to fully explore predictors for gun ownership. Employing 2015 Pew Research Center political survey data, this study examines the predictive effects of birth cohort, political ideology,...
Show moreWith mass shootings occurring with frightening regularity, research into gun ownership behavior is becoming increasingly important for public policy creation and public safety. While extant research tells us that firearm ownership is woven deep into the historical fabric of American culture, scholarship has yet to fully explore predictors for gun ownership. Employing 2015 Pew Research Center political survey data, this study examines the predictive effects of birth cohort, political ideology, and attitudes towards gun control legislation on gun ownership, with and without controls, using hierarchical binary logistic regression models. The presented models examine three separate cohorts: The Millennials, Generation X, and the Baby Boomers. Findings reveal that Millennials, liberal political ideology, attitudes which stress the importance of controlling, as opposed to protecting, gun ownership are significantly less likely to own a firearm. Furthermore, gender, household income, population density, southern residency, and race were also found to significantly influence gun ownership. Implications, limitations, and recommendations for future research are also discussed. While this research cannot perfectly predict individual gun ownership, it does effectively highlight several important facts to consider. From the fog of media speculation, political grandstanding, and overly simplistic and unwarranted assumptions, the results of this study bring into full view the inherent complexity of American gun ownership.
Show less
Date Issued: 2017
Identifier: CFE0006706, ucf:51913
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006706

Title: Fluid Dynamics Modeling and Sound Analysis of a Bileaflet Mechanical Heart Valve.
Creator: Khalili, Fardin, Mansy, Hansen, Kassab, Alain, Steward, Robert, Zaurin, Ricardo, University of Central Florida
Abstract / Description: Cardiovascular disease (CVD) is one of the main causes of death in the world. Some CVD involve severe heart valve disease that require valve replacement. There are more than 300,000 heart valves implanted worldwide, and about 85,000 heart valve replacements in the US. Approximately half of these valves are mechanical. Artificial valves may dysfunction leading to adverse hemodynamic conditions. Understanding the normal and abnormal valve function is important as it help improve valve designs....
Show moreCardiovascular disease (CVD) is one of the main causes of death in the world. Some CVD involve severe heart valve disease that require valve replacement. There are more than 300,000 heart valves implanted worldwide, and about 85,000 heart valve replacements in the US. Approximately half of these valves are mechanical. Artificial valves may dysfunction leading to adverse hemodynamic conditions. Understanding the normal and abnormal valve function is important as it help improve valve designs. Modeling of heart valve hemodynamics using computational fluid dynamics (CFD) provides a comprehensive analysis of flow, which can potentially help explain clinical observations and support therapeutic decision-making. This detailed information might not be accessible with in-vivo measurements. On the other hand, finite element analysis (FEA), is an efficient way to analyze the interactions of blood flow with blood vessel and tissue layers. In this project both CFD and FEA simulations were performed to investigate the flow-induced sound generation and propagation of sound waves through a tissue-like material. This method is based on mapping the transient pressure (force) fluctuations on the vessel wall and solving for the structural vibrations in the frequency domain. These vibrations would then be detected as sound on the epidermal surface. Advantages of the methods used in the current study include: (a) capability of providing accurate solution with a faster solution time; (b) inclusion of the fluid(-)structure interaction between blood flow and the arterial wall; and (c) accurately capturing some of the spectral features of the velocity fluctuation measured over the epidermal surface.
Show less
Date Issued: 2018
Identifier: CFE0007029, ucf:52038
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007029

Title: DESIGN OF HIGH EFFICIENCY BRUSHLESS PERMANENT MAGNET MACHINES AND DRIVER SYSTEM.
Creator: He, Chengyuan, Wei, Lei, Sundaram, Kalpathy, Zhou, Qun, Jin, Yier, Zou, Shengli, University of Central Florida
Abstract / Description: The dissertation is concerned with the design of high-efficiency permanent magnet synchronous machinery and the control system. The dissertation first talks about the basic concept of the permanent magnet synchronous motor (PMSM) design and the mathematics design model of the advanced design method. The advantage of the design method is that it can increase the high load capacity at no cost of increasing the total machine size. After that, the control method of the PMSM and Permanent magnet...
Show moreThe dissertation is concerned with the design of high-efficiency permanent magnet synchronous machinery and the control system. The dissertation first talks about the basic concept of the permanent magnet synchronous motor (PMSM) design and the mathematics design model of the advanced design method. The advantage of the design method is that it can increase the high load capacity at no cost of increasing the total machine size. After that, the control method of the PMSM and Permanent magnet synchronous generator (PMSG) is introduced. The design, simulation, and test of a permanent magnet brushless DC (BLDC) motor for electric impact wrench and new mechanical structure are first presented based on the design method. Finite element analysis based on the Maxwell 2D is built to optimize the design and the control board is designed using Altium Designer. Both the motor and control board have been fabricated and tested to verify the design. The electrical and mechanical design are combined, and it provides an analytical IPMBLDC design method and an innovative and reasonable mechanical dynamical calculation method for the impact wrench system, which can be used in whole system design of other functional electric tools. A 2kw high-efficiency alternator system and its control board system are also designed, analyzed and fabricated applying to the truck auxiliary power unit (APU). The alternator system has two stages. The first stage is that the alternator three-phase outputs are connected to the three-phase active rectifier to get 48V DC. An advanced Sliding Mode Observer (SMO) is used to get an alternator position. The buck is used for the second stage to get 14V DC output. The whole system efficiency is much higher than the traditional system using induction motor.
Show less
Date Issued: 2018
Identifier: CFE0007334, ucf:52135
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007334

Title: Analysis, Design and Efficiency Optimization of Power Converters for Renewable Energy Applications.
Creator: Chen, Xi, Batarseh, Issa, Zhou, Qun, Mikhael, Wasfy, Sun, Wei, Kutkut, Nasser, University of Central Florida
Abstract / Description: DC-DC power converters are widely used in renewable energy-based power generation systems due to the constant demand of high-power density and high-power conversion efficiency. DC-DC converters can be classified into non-isolated and isolated topologies. For non-isolated topologies, they are typically derived from buck, boost, buck-boost or forth order (such as Cuk, Sepic and Zeta) converters and they usually have relatively higher conversion efficiency than isolated topologies. However, with...
Show moreDC-DC power converters are widely used in renewable energy-based power generation systems due to the constant demand of high-power density and high-power conversion efficiency. DC-DC converters can be classified into non-isolated and isolated topologies. For non-isolated topologies, they are typically derived from buck, boost, buck-boost or forth order (such as Cuk, Sepic and Zeta) converters and they usually have relatively higher conversion efficiency than isolated topologies. However, with the applications where the isolation is required, either these topologies should be modified, or alternative topologies are needed. Among various isolated DC-DC converters, the LLC resonant converter is an attractive selection due to its soft switching, isolation, wide gain range, high reliability, high power density and high conversion efficiency.In low power applications, such as battery chargers and solar microinverters, increasing the switching frequency can reduce the size of passive components and reduce the current ripple and root-mean-square (RMS) current, resulting in higher power density and lower conduction loss. However, switching losses, gate driving loss and electromagnetic interference (EMI) may increase as a consequence of higher switching frequency. Therefore, switching frequency modulation, components optimization and soft switching techniques have been proposed to overcome these issues and achieve a tradeoff to reach the maximum conversion efficiency.This dissertation can be divided into two categories: the first part is focusing on the well-known non-isolated bidirectional cascaded-buck-boost converter, and the second part is concentrating on the isolated dual-input single resonant tank LLC converter. Several optimization approaches have been presented to improve the efficiency, power density and reliability of the power converters. In the first part, an adaptive switching frequency modulation technique has been proposed based on the precise loss model in this dissertation to increase the efficiency of the cascaded-buck-boost converter. In adaptive switching frequency modulation technique, the optimal switching frequency for the cascaded-buck-boost converter is adaptively selected to achieve the minimum total power loss. In addition, due to the major power losses coming from the inductor, a new low profile nanocrystalline inductor filled with copper foil has been designed to significantly reduce the core loss and winding loss. To further improve the efficiency of the cascaded-buck-boost converter, the adaptive switching frequency modulation technique has been applied on the converter with designed nanocrystalline inductor, in which the peak efficiency of the converter can break the 99% bottleneck.In the second part, a novel dual-input DC-DC converter is developed according to the LLC resonant topology. This design concept minimizes the circuit components by allowing single resonant tank to interface with multiple input sources. Based on different applications, the circuit configuration for the dual-input LLC converter will be a little different. In order to improve the efficiency of the dual-input LLC converter, the semi-active rectifiers have been used on the transformer secondary side to replace the low-side bridge diodes. In this case, higher magnetizing inductance can be selected while maintaining the same voltage gain. Besides, a burst-mode control strategy has been proposed to improve the light load and very light load efficiency of the dual- input LLC converter. This control strategy is able to be readily implemented on any power converter since it can be achieved directly through firmware and no circuit modification is needed in implementation of this strategy.
Show less
Date Issued: 2019
Identifier: CFE0007612, ucf:52531
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007612

Finite Element Method (6)	+ -
finite element method (4)	+ -
mixed methods research (4)	+ -
Mixed Methods (3)	+ -
Modeling (3)	+ -

meshless methods (3)	+ -
mixed methods (3)	+ -
quantitative methods (3)	+ -
Computational Fluid Dynamics (2)	+ -
Content Analysis (2)	+ -
Fast/ Equilibrium Reactions (2)	+ -
Fully-implicit (2)	+ -
Heat transfer (2)	+ -
Highway Safety Manual (2)	+ -
Kinetic-Variable (2)	+ -
Lagrangian-Eulerian approach (2)	+ -
Machine Learning (2)	+ -
Meshless Methods (2)	+ -
Mixed-Methods (2)	+ -
Operator-splitting (2)	+ -
Predictor-corrector (2)	+ -
Reactive Chemical Transport (2)	+ -
Simulation (2)	+ -
Slow/Kinetic Reactions (2)	+ -
boundary element method (2)	+ -
hedonic method (2)	+ -
high school (2)	+ -
intervention (2)	+ -
qualitative methods (2)	+ -
teaching methods (2)	+ -

ETD Collection (102)	+ -
Honors Collection (11)	+ -

University of Central Florida (112)	+ -
Kassab, Alain (12)	+ -
Divo, Eduardo (5)	+ -
Moore, Brian (5)	+ -
Bai, Haiyan (4)	+ -

Behal, Aman (4)	+ -
Georgiopoulos, Michael (4)	+ -
Hagen, Scott (4)	+ -
Kumar, Ranganathan (4)	+ -
Mohapatra, Ram (4)	+ -
Anagnostopoulos, Georgios (3)	+ -
Chopra, Manoj (3)	+ -
Choudhury, Sudipto (3)	+ -
Corzine, Harold (3)	+ -
Dixon, Juli (3)	+ -
Eluru, Naveen (3)	+ -
Hopp, Carolyn (3)	+ -
Leavens, Gary (3)	+ -
Rabelo, Luis (3)	+ -
Stanley, Kenneth (3)	+ -
Xanthopoulos, Petros (3)	+ -
Yuan, Jiann-Shiun (3)	+ -
Abdel-Aty, Mohamed (2)	+ -
Bai, Yuanli (2)	+ -
Boote, David (2)	+ -
Butler, Malcolm (2)	+ -
Caputo, Michael (2)	+ -
Chen, Xi (2)	+ -
Doherty, Walter (2)	+ -
Elshennawy, Ahmad (2)	+ -

Search In

Pages

Pages

Sort Results By:

Narrow results by:

Topical Subject

Collection

Type of Resource

Language

Creator

Format

Owner