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- Title
- A phenomenological study of Black fifth grade students' perceptions of social studies and a discussion with secondary students.
- Creator
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Walker, Irenea, Russell, William, Hewitt, Randall, Hopp, Carolyn, Huff-Corzine, Lin, University of Central Florida
- Abstract / Description
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The problem I address in this study is the lack of Black elementary students' knowledge and interest of the social studies content. Black students who lack a true identity of self, fail to develop into productive citizens. Although previous studies have examined Black students' experiences in secondary social studies classrooms, few have thoroughly examined Black students' experiences in the elementary classrooms. For this study, I analyze Black fifth grade students' perceptions of the social...
Show moreThe problem I address in this study is the lack of Black elementary students' knowledge and interest of the social studies content. Black students who lack a true identity of self, fail to develop into productive citizens. Although previous studies have examined Black students' experiences in secondary social studies classrooms, few have thoroughly examined Black students' experiences in the elementary classrooms. For this study, I analyze Black fifth grade students' perceptions of the social studies content. Identifying these perceptions is imperative so educators can adjust their pedagogical practices based on what they deem as important for educational growth, and the experiences of Black students. Allowing Black students to share their experiences and express their thoughts is conducive to their knowledge and awareness of the subject (Scott, 2017). To grasp an authentic analysis of student understanding educators must start in the primary grades. Previous research highlights that curriculum and instruction fails to align with what students, especially Black students need to be successful in the classroom. Identifying these areas in elementary school will create a smooth transition for students as they advance to the next level.
Show less - Date Issued
- 2018
- Identifier
- CFE0007591, ucf:52547
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007591
- Title
- Analysis of Nucleus Properties of the Enigmatic Comet 29P/Schwassmann-Wachmann 1.
- Creator
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Schambeau, Charles, Fernandez, Yan, Britt, Daniel, Kokoouline, Viatcheslav, Samarasinha, Nalin, University of Central Florida
- Abstract / Description
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We present results from a continuing effort to understand activity drivers for the enigmatic Comet 29P/Schwassmann-Wachmann 1 (SW1). SW1 has been of interest since its discovery almost 100 years ago because of its nearly continuous, quiescent activity beyond the water-sublimation line and its highly variable, outburst activity while receiving a nearly constant insolation due to its low eccentricity orbit. These characteristics make SW1 a useful target for investigating both distant cometary...
Show moreWe present results from a continuing effort to understand activity drivers for the enigmatic Comet 29P/Schwassmann-Wachmann 1 (SW1). SW1 has been of interest since its discovery almost 100 years ago because of its nearly continuous, quiescent activity beyond the water-sublimation line and its highly variable, outburst activity while receiving a nearly constant insolation due to its low eccentricity orbit. These characteristics make SW1 a useful target for investigating both distant cometary activity drivers and also cometary outburst behavior. We approach answering these ques- tions through a detailed analysis of SW1; first by measuring nucleus properties required for a more accurate nucleus thermophysical modeling and second, by applying thermal modeling to replicate its activity. Our project began with an analysis of Spitzer Space Telescope infrared observations of SW1 from 2003. Coma removal techniques when applied to the images provided nucleus photometry measurements. Application of the Near Earth Asteroid Thermal Model (NEATM) to these measured photometry values resulted in an effective nucleus radius of 32.3 (&)#177; 3.1 km and a thermal beaming parameter of 1.14 (&)#177;0.22. These results indicated that SW1 is one of the largest Jupiter Family Comets and also has a relatively smooth overall surface and/or a low thermal inertia. We next placed constraints on the nucleus' spin state through analysis of evolution seen in the coma's morphological structure through two sets of outburst coma observations. The first set analyzed are from the Kitt Peak 2.1-m telescope taken ~2 days after a major outburst in 2008. 3-D Monte Carlo coma modeling showed that the nucleus' spin period is on the order of days and/or the spin pole orientation was along the Earth's directions during observations. The second set are Hubble Space Telescope observations from 1996 taken ~15 hours after a major outburst. Modeling similarly showed a rotation period on the order of days. Due to the observing geometry differing between the 2008 and 1996 observations, we conclude the rotation period lower limit must be on the order of days even if the spin-pole direction was directed along the sub-Earth direction during one set of observations. The nucleus properties measured or constrained by our project were incorporated into a thermophysical model to replicate the quiescent activity via the sublimation of the supervolatile species CO or CO2. A progenitor nucleus was thermally evolved in SW1's current orbit using different plausible nucleus interior compositional and layering schemes. We discuss results of this analysis and additionally possibilities for future thermal modeling efforts.
Show less - Date Issued
- 2018
- Identifier
- CFE0007585, ucf:52548
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007585
- Title
- An Agent Based Model to assess crew temporal variability during U.S. Navy shipboard operations.
- Creator
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Muhs, Kevin, Karwowski, Waldemar, Elshennawy, Ahmad, Hancock, Peter, Sjoden, Glenn, University of Central Florida
- Abstract / Description
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Understanding the factors that affect human performance variability as well as their temporal impacts is an essential element in fully integrating and designing complex, adaptive environments. This understanding is particularly necessary for high stakes, time-critical routines such as those performed during nuclear reactor, air traffic control, and military operations. Over the last three decades significant efforts have emerged to demonstrate and apply a host of techniques to include...
Show moreUnderstanding the factors that affect human performance variability as well as their temporal impacts is an essential element in fully integrating and designing complex, adaptive environments. This understanding is particularly necessary for high stakes, time-critical routines such as those performed during nuclear reactor, air traffic control, and military operations. Over the last three decades significant efforts have emerged to demonstrate and apply a host of techniques to include Discrete Event Simulation, Bayesian Belief Networks, Neural Networks, and a multitude of existing software applications to provide relevant assessments of human task performance and temporal variability. The objective of this research was to design and develop a novel Agent Based Modeling and Simulation (ABMS) methodology to generate a timeline of work and assess impacts of crew temporal variability during U.S. Navy Small Boat Defense operations in littoral waters.The developed ABMS methodology included human performance models for six crew members (agents) as well as a threat craft, and incorporated varying levels of crew capability and task support. AnyLogic ABMS software was used to simultaneously provide detailed measures of individual sailor performance and of system-level emergent behavior. This methodology and these models were adapted and built to assure extensibility across a broad range of U.S. Navy shipboard operations.Application of the developed ABMS methodology effectively demonstrated a way to visualize and quantify impacts/uncertainties of human temporal variability on both workload and crew effectiveness during U.S. Navy shipboard operations.
Show less - Date Issued
- 2018
- Identifier
- CFE0007592, ucf:52549
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007592
- Title
- Influence of Selected Factors on a Counselor's Attention Level to and Counseling Performance with a Virtual Human in a Virtual Counseling Session.
- Creator
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Hart, John, Proctor, Michael, Jentsch, Florian, Li, Daoji, Morie, Jacquelyn, University of Central Florida
- Abstract / Description
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Virtual humans serve as role-players in social skills training environments simulating situational face-to-face conversations. Previous research indicates that virtual humans in instructional roles can increase a learner's engagement and motivation towards the training. Left unaddressed is if the learner is looking at the virtual human as one would in a human-to-human, face-to-face interaction. Using a modified version of the Emergent Leader Immersive Training Environment (ELITE-Lite), this...
Show moreVirtual humans serve as role-players in social skills training environments simulating situational face-to-face conversations. Previous research indicates that virtual humans in instructional roles can increase a learner's engagement and motivation towards the training. Left unaddressed is if the learner is looking at the virtual human as one would in a human-to-human, face-to-face interaction. Using a modified version of the Emergent Leader Immersive Training Environment (ELITE-Lite), this study tracks visual attention and other behavior of 120 counselor trainees counseling a virtual human role-playing counselee. Specific study elements include: (1) the counselor's level of visual attention toward the virtual counselee; (2) how changes to the counselor's viewpoint may influence the counselor's visual focus; and (3) how levels of the virtual human's behavior may influence the counselor's visual focus. Secondary considerations include aspects of learner performance, acceptance of the virtual human, and impacts of age and rank. Result highlights indicate that counselor visual attentional behavior could be separated into two phases: when the virtual human was speaking and when not speaking. When the virtual human is speaking, the counselor's primary visual attention is on the counselee, but is also split toward pre-scripted responses required for the training session. During the non-speaking phase, the counselor's visual focus was on pre-scripted responses required for training. Some of the other findings included that participants did not consider this to be like a conversation with a human, but they indicated acceptance of the virtual human as a partner with the training environment and they considered the simulation to be a useful experience. Additionally, the research indicates behavior may differ due to age or rank. Future study and design considerations for enhancements to social skills training environments are provided.
Show less - Date Issued
- 2018
- Identifier
- CFE0007571, ucf:52572
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007571
- Title
- Quantitative Line Assignment in Optical Emission Spectroscopy.
- Creator
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Chappell, Jessica, Baudelet, Matthieu, Hernandez, Florencio, Campiglia, Andres, Ni, Liqiang, Sigman, Michael, University of Central Florida
- Abstract / Description
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Quantitative elemental analysis using Optical Emission Spectroscopy (OES) starts with a high level of confidence in spectral line assignment from reference databases. Spectral interferences caused by instrumental and line broadening decrease the resolution of OES spectra creating uncertainty in the elemental profile of a sample for the first time. An approach has been developed to quantify spectral interferences for individual line assignment in OES. The algorithm calculates a statistical...
Show moreQuantitative elemental analysis using Optical Emission Spectroscopy (OES) starts with a high level of confidence in spectral line assignment from reference databases. Spectral interferences caused by instrumental and line broadening decrease the resolution of OES spectra creating uncertainty in the elemental profile of a sample for the first time. An approach has been developed to quantify spectral interferences for individual line assignment in OES. The algorithm calculates a statistical interference factor (SIF) that combines a physical understanding of plasma emission with a Bayesian analysis of the OES spectrum. It can be used on a single optical spectrum and still address individual lines. Contrary to current methods, quantification of the uncertainty in elemental profiles of OES, leads to more accurate results, higher reliability and validation of the method. The SIF algorithm was evaluated for Laser-Induced Breakdown Spectroscopy (LIBS) on samples with increasing complexity: from silicon to nickel spiked alumina to NIST standards (600 glass series and nickel-chromium alloy). The influence of the user's knowledge of the sample composition was studied and showed that for the majority of spectral lines this information is not changing the line assignment for simple compositions. Nonetheless, the amount of interference could change with this information, as expected. Variance of the SIF results for NIST glass standard was evaluated by the chi-square hypothesis test of variance showing that the results of the SIF algorithm are very reproducible.
Show less - Date Issued
- 2018
- Identifier
- CFE0007564, ucf:52575
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007564
- Title
- Electrochemical Microsensors for In Situ Monitoring of Chemical Compounds in Engineered and Natural Aquatic Systems.
- Creator
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Church, Jared, Lee, Woo Hyoung, Randall, Andrew, Duranceau, Steven, University of Central Florida
- Abstract / Description
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The adaption of needle-type electrochemical microsensor (or microelectrode) techniques to environmental science and engineering systems has transformed how we understand mass transport in biotic and abiotic processes. Their small tip diameter (5-20(&)#181;m) makes them a unique experimental tool for direct measurements of analytes with high spatial and temporal resolutions, providing a quantitative analysis of flux, diffusion, and reaction rate at a microscale that cannot be obtained using...
Show moreThe adaption of needle-type electrochemical microsensor (or microelectrode) techniques to environmental science and engineering systems has transformed how we understand mass transport in biotic and abiotic processes. Their small tip diameter (5-20(&)#181;m) makes them a unique experimental tool for direct measurements of analytes with high spatial and temporal resolutions, providing a quantitative analysis of flux, diffusion, and reaction rate at a microscale that cannot be obtained using conventional analytical tools. However, their applications have been primarily limited to understanding mass transport dynamics and kinetics in biofilms. With the advancement of sensor fabrication and utilization techniques, their potential applications can surpass conventional biofilm processes. In this dissertation, microsensors were utilized to elucidate mass transport and chemical reactions in multidisciplinary research areas including biological nutrient uptake, oily wastewater treatment, photocatalytic disinfection, and plant disease management, which have not yet explored using this emerging technology. The main objective of this work was to develop novel microsensors and use them for better understanding various natural and engineered aquatic systems. These include; 1) investigating localized photo-aeration and algal-bacterial symbiotic interaction in an advanced algal-bacterial biofilm process for nutrient removal from wastewater, 2) characterizing oil-in-water emulsions for better understanding bilge water emulsion stability, 3) evaluating sun-light driven photocatalytic reactions using a novel MoS2 nanofilm for water disinfection and microcystins-LR removal, 4) developing a zinc ion-selective microsensor and applying them for monitoring the transport of zinc in citrus trees, and 5) integrating heavy metal detection using anodic stripping voltammetry (ASV) in a microelectrode platform for plant applications.
Show less - Date Issued
- 2018
- Identifier
- CFE0007565, ucf:52576
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007565
- Title
- The Power of Play: Creating A Theatre for the Very Young Experience.
- Creator
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Katsadouros, Maria, Listengarten, Julia, StClaire, Sybil, Freeman, Emily, University of Central Florida
- Abstract / Description
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The opportunity to enhance the sense of fulfillment necessary in revolutionizing and liberating a person's daily life, regardless of their age, can be found in the manifestation of play. It is through the acknowledgment of instinct, nature, and discovery that play reveals its power. As a Theatre for the Very Young (TVY) practitioner, I utilize creative play to inspire exploration and innovation among students under the age of six. However, what are the ways in which theatre, specifically TVY,...
Show moreThe opportunity to enhance the sense of fulfillment necessary in revolutionizing and liberating a person's daily life, regardless of their age, can be found in the manifestation of play. It is through the acknowledgment of instinct, nature, and discovery that play reveals its power. As a Theatre for the Very Young (TVY) practitioner, I utilize creative play to inspire exploration and innovation among students under the age of six. However, what are the ways in which theatre, specifically TVY, invites all generations of people to experience the power of play? This thesis documents the three-year development of When Pigs Fly, an original TVY experience that encourages audience members of all ages to engage in creative play through sensation, fellowship and discovery. This study explores the collective creation of When Pigs Fly as developed through research, education, and practice. In highlighting the cognitive and emotional benefits of creative play, this study seeks to legitimize TVY as a valued art form, and invites theatre-makers to utilize the research and practice shared to inspire future endeavors that will shape the outlook of TVY throughout the United States.
Show less - Date Issued
- 2018
- Identifier
- CFE0007405, ucf:52882
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007405
- Title
- Characterization of Anisotropic Mechanical Performance of As-Built Additively Manufactured Metals.
- Creator
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Siddiqui, Sanna, Gordon, Ali, Raghavan, Seetha, Bai, Yuanli, Sohn, Yongho, University of Central Florida
- Abstract / Description
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Additive manufacturing (AM) technologies use a 3D Computer Aided Design (CAD) model to develop a component through a deposition and fusion layer process, allowing for rapid design and geometric flexibility of metal components, for use in the aerospace, energy and biomedical industries. Challenges exist with additive manufacturing that limits its replacement of conventional manufacturing techniques, most especially a comprehensive understanding of the anisotropic behavior of these materials...
Show moreAdditive manufacturing (AM) technologies use a 3D Computer Aided Design (CAD) model to develop a component through a deposition and fusion layer process, allowing for rapid design and geometric flexibility of metal components, for use in the aerospace, energy and biomedical industries. Challenges exist with additive manufacturing that limits its replacement of conventional manufacturing techniques, most especially a comprehensive understanding of the anisotropic behavior of these materials and how it is reflected in observed tensile, torsional and fatigue mechanical responses. As such, there is a need to understand how the build orientation of as-built additively manufactured metals, affects mechanical performance (e.g. monotonic and cyclic behavior, cyclically hardening/softening behavior, plasticity effects on fatigue life etc.); and to use constitutive modeling to both support experimental findings, and provide approximations of expected behavior (e.g. failure surfaces, monotonic and cyclic response, correlations between tensile and fatigue properties), for orientations and experiments not tested, due to the expensive cost associated with AM. A comprehensive framework has been developed to characterize the anisotropic behavior of as-built additively manufactured metals (i.e. Stainless Steel GP1 (SS GP1), similar in chemical composition to Stainless Steel 17-4PH), through a series of mechanical testing, microscopic evaluation and constitutive modeling, which were used to identify a reduced specimen size for characterizing these materials. An analysis of the torsional response of additively manufactured Inconel 718 has been performed to assess the impact of build orientation and as-built conditions on the shearing behavior of this material. Experimental results from DMLS SS GP1 and AM Inconel 718 from literature were used to constitutively model the material responses of these additively manufactured metals. Overall, this framework has been designed to serve as standard, from which build orientation selection can be used to meet specific desired industry requirements.
Show less - Date Issued
- 2018
- Identifier
- CFE0007097, ucf:52883
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007097
- Title
- Econometric Modeling Analysis of Public Transit Ridership: Application for Orlando Region.
- Creator
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Rahman, Moshiur, Eluru, Naveen, Abdel-Aty, Mohamed, Yasmin, Shamsunnahar, Uddin, Nizam, University of Central Florida
- Abstract / Description
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Policy makers are considering several alternatives to counter the negative externalities of personal vehicle dependence. Towards this end, public transit investments are critical in growing urban regions such as Orlando, Florida. Transit system managers and planners mostly rely on statistical models to identify the factors that affect ridership as well as quantifying the magnitude of the impact on the society. These models provide vital feedback to agencies on the benefits of public transit...
Show morePolicy makers are considering several alternatives to counter the negative externalities of personal vehicle dependence. Towards this end, public transit investments are critical in growing urban regions such as Orlando, Florida. Transit system managers and planners mostly rely on statistical models to identify the factors that affect ridership as well as quantifying the magnitude of the impact on the society. These models provide vital feedback to agencies on the benefits of public transit investments which in turn act as lessons to improve the investment process. We contribute to public transit literature by addressing several methodological challenges for transit ridership modeling. Frist, we examine the impact of new transit investments (such as an addition of commuter rail to an urban region) on existing transit infrastructure (such as the traditional bus service already present in the urban region). The process of evaluating the impact of new investments on existing public transit requires a comprehensive analysis of the before and after measures of public transit usage in the region. Second, we accommodate for the presence of common unobserved factors associated with spatial factors by developing a spatial panel model using stop level public transit boarding and alighting data. Third, we contribute to literature on transit ridership by considering daily boarding and alighting data from a recently launched commuter rail system (SunRail). The model system developed will allow us to predict ridership for existing stations in the future as well as potential ridership for future expansion sites. Fourth, we accommodate for potential endogeneity between bus headway and ridership by proposing a simultaneous model system of headway and ridership. Finally, a cost benefit analysis exercise is conducted for examining the impact of Sunrail on the region.
Show less - Date Issued
- 2018
- Identifier
- CFE0007583, ucf:52577
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007583
- Title
- Electrospray and Superlens Effect of Microdroplets for Laser-Assisted Nanomanufacturing.
- Creator
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Castillo Orozco, Eduardo, Kumar, Ranganathan, Mansy, Hansen, Peles, Yoav, University of Central Florida
- Abstract / Description
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Nanoparticles of various materials are known to exhibit excellent mechanical, chemical, electrical, and optical properties. However, it is difficult to deposit and transform nanoparticles into large two-dimensional and three-dimensional structures, such as thin films and discrete arrays. Electrospray technology and laser heating enable the deposition of these nanoparticles through the dual role of microdroplets as nanoparticle carriers and superlenses. The main goals of this dissertation are...
Show moreNanoparticles of various materials are known to exhibit excellent mechanical, chemical, electrical, and optical properties. However, it is difficult to deposit and transform nanoparticles into large two-dimensional and three-dimensional structures, such as thin films and discrete arrays. Electrospray technology and laser heating enable the deposition of these nanoparticles through the dual role of microdroplets as nanoparticle carriers and superlenses. The main goals of this dissertation are to delineate the electrospray modes, to achieve subwavelength focusing, and to enable a process for the deposition of nanoparticles into microlayers and discrete nanodots (a nanodot is a cluster of nanoparticles) on rigid and flexible substrates. This additive manufacturing process is based on the electrospray generation of water microdroplets that carry nanoparticles onto a substrate and the laser sintering of these nanoparticles. The process involves injecting nanoparticles (contained inside electric field-driven water microdroplets) into a hollow laser beam. The laser beam heats the droplets, causing the water to evaporate and the nanoparticles to sinter and form deposit of material on the substrate.The electrohydrodynamic inkjet printing of nanoparticle suspensions has been accomplished by the operation of an electrospray in microdripping mode and it allows the deposition of monodisperse microdroplets containing nanoparticles into discrete nanodot arrays, narrow lines, and thin films. For flow rates with low Reynolds number, the mode changes from dripping to microdripping mode, and then to a planar oscillating microdripping mode as the electric capillary number, Cae increases. The microdripping mode which is important for depositing discrete array of nanodots is found to occur in a narrow range, 2 ? Cae ? 2.5. The effect of the physical properties on the droplet size and frequency of droplet formation is more precisely described by the relative influence of the electric, gravity, viscous, and capillary forces. A scaling analysis is derived from a fundamental force balance and has yielded a parameter based on the electric capillary number, capillary number, and Bond number. Results for different nanoparticle suspensions with a wide range of physical properties show that the normalized radius of droplet, can be correlated using this parameter in both dripping and microdripping modes. The same parameter also correlates the normalized frequency of droplet formation, Nd* as an increasing function in the microdripping mode. Viscosity affects the shape of the cone by resisting its deformation and thus promoting a stable microdripping mode. Reduction in surface tension decreases the droplet size in the electrospray modes. However, the capillary size and electrical conductivity have minimal effect on the size of the ejected droplets. Electrical conductivity affects the transition between microdripping and oscillating microdripping modes. Based on this analysis, it is possible to design the electrospray to produce uniform monodisperse droplets by manipulating the voltage at the electrode, for any desired nanoparticle concentration of a suspension to be sintered on a substrate. For the fabrication of nanodots, a laser beam of wavelength ? = 1064 nm was focused to a diameter smaller than its wavelength. When the microdroplets did not carry nanoparticles, the subwavelength focusing of the laser yielded nanoholes smaller than its wavelength. Results show that tiny features with high resolution can be created by loading microdroplets with nanoparticles and squeezing the laser beam to subwavelength regions. Nanodots of silicon and germanium with diameters between 100 - 500 nm have been deposited on a silicon substrate. This study demonstrates an interdisciplinary mechanism to achieve subwavelength focusing in a laser process. In this process, the microdroplets serve as both a nanoparticle carrier and a superlens that focuses a laser beam to subwavelength diameters up to ? /10, thus overcoming the diffraction limit. The microdroplets are generated from a suspension of nanoparticles using an electrospray technique and the superlens characteristic of these microdroplets is attributed to three optical phenomena such as Maxwell's fish eye lens or L(&)#252;neberg lens, evanescent waves by laser scattering, and evanescent waves by the total internal reflection principle. A microfluidic cooling effect can also contribute to creating subwavelength features. In summary, this work describes a new laser-assisted additive manufacturing process for the fabrication of nanodots and microlayers using nanoparticles of different materials. In this process, microdroplets from an electrospray are used as nanoparticle carriers and superlenses to focus the laser to a diameter smaller than its wavelength. While this process is demonstrated to produce subwavelength holes and nanodots, the process is scalable to produce narrow lines and thin films of semiconductor materials by an additive manufacturing technique. This process extends the application of infrared lasers to the production of nanostructures and nanofeatures, and, therefore, provides a novel technology for nanomanufacturing.
Show less - Date Issued
- 2018
- Identifier
- CFE0007563, ucf:52579
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007563
- Title
- A Review and Selective Analysis of 3D Display Technologies for Anatomical Education.
- Creator
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Hackett, Matthew, Proctor, Michael, Allen, Christine, Wiegand, Rudolf, Sims, Valerie, University of Central Florida
- Abstract / Description
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The study of anatomy is complex and difficult for students in both graduate and undergraduate education. Researchers have attempted to improve anatomical education with the inclusion of three-dimensional visualization, with the prevailing finding that 3D is beneficial to students. However, there is limited research on the relative efficacy of different 3D modalities, including monoscopic, stereoscopic, and autostereoscopic displays. This study analyzes educational performance, confidence,...
Show moreThe study of anatomy is complex and difficult for students in both graduate and undergraduate education. Researchers have attempted to improve anatomical education with the inclusion of three-dimensional visualization, with the prevailing finding that 3D is beneficial to students. However, there is limited research on the relative efficacy of different 3D modalities, including monoscopic, stereoscopic, and autostereoscopic displays. This study analyzes educational performance, confidence, cognitive load, visual-spatial ability, and technology acceptance in participants using autostereoscopic 3D visualization (holograms), monoscopic 3D visualization (3DPDFs), and a control visualization (2D printed images). Participants were randomized into three treatment groups: holograms (n=60), 3DPDFs (n=60), and printed images (n=59). Participants completed a pre-test followed by a self-study period using the treatment visualization. Immediately following the study period, participants completed the NASA TLX cognitive load instrument, a technology acceptance instrument, visual-spatial ability instruments, a confidence instrument, and a post-test. Post-test results showed the hologram treatment group (Mdn=80.0) performed significantly better than both 3DPDF (Mdn=66.7, p=.008) and printed images (Mdn=66.7, p=.007). Participants in the hologram and 3DPDF treatment groups reported lower cognitive load compared to the printed image treatment (p (<) .01). Participants also responded more positively towards the holograms than printed images (p (<) .001). Overall, the holograms demonstrated significant learning improvement over printed images and monoscopic 3DPDF models. This finding suggests additional depth cues from holographic visualization, notably head-motion parallax and stereopsis, provide substantial benefit towards understanding spatial anatomy. The reduction in cognitive load suggests monoscopic and autostereoscopic 3D may utilize the visual system more efficiently than printed images, thereby reducing mental effort during the learning process. Finally, participants reported positive perceptions of holograms suggesting implementation of holographic displays would be met with enthusiasm from student populations. These findings highlight the need for additional studies regarding the effect of novel 3D technologies on learning performance.
Show less - Date Issued
- 2018
- Identifier
- CFE0007569, ucf:52571
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007569
- Title
- Comparison of a modified and traditional rapid infiltration basin for treatment and control of nutrients in wastewater effluent.
- Creator
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Cormier, Jessica, Duranceau, Steven, Wang, Dingbao, Sadmani, A H M Anwar, University of Central Florida
- Abstract / Description
-
Rapid infiltration basins (RIB) have been historically used in Florida for groundwater recharge, effluent disposal, or a combination of both. However, this technique has proven ineffective in providing nitrogen control unless the RIB is modified in some manner. In this study, a traditional RIB was compared to a modified RIB constructed with manufactured biosorption activated media (BAM) to evaluate nitrate removal from reclaimed water. The RIBs are used for reclaimed and excess storm water...
Show moreRapid infiltration basins (RIB) have been historically used in Florida for groundwater recharge, effluent disposal, or a combination of both. However, this technique has proven ineffective in providing nitrogen control unless the RIB is modified in some manner. In this study, a traditional RIB was compared to a modified RIB constructed with manufactured biosorption activated media (BAM) to evaluate nitrate removal from reclaimed water. The RIBs are used for reclaimed and excess storm water disposal. Few, if any, studies have been published where BAM-modified RIBs have been used for this purpose. In this work, a mixture of clay, tire crumb, and sand (CTS) was selected to serve as the BAM material (Bold and Gold(TM) CTS media). Each RIB was constructed with two feet of either sand or BAM, covering more than 43,600 square feet of surface area. The BAM-modified RIB had an initial 90 pounds per cubic-foot in-place density, and the density of the control RIB approximated about 94 pounds per cubic-foot. Over an eight-month period, loadings to the BAM RIB and control RIB approximated 5.4 million gallons (MG) per acre each. Water samples, collected from lysimeters installed below the 2-foot of sand or BAM materials, were gathered monthly during 2017 (except for September and October due to the impacts of hurricane Irma); these samples were analyzed for water quality to determine nitrate removal. Soil moisture and weather data were also collected over the study period. This study demonstrated the nitrate removal effectiveness of a field-scale BAM-modified RIB as compared to a traditional field-scale sand-based RIB. Results suggest that BAM removed 30 percent more nitrates than the Control (78% and 47%, respectively) under the conditions of the study. Furthermore, BAM removed higher percentages of TN (31%) and TP (62%) than the Control (12% and 28%, respectively).
Show less - Date Issued
- 2018
- Identifier
- CFE0007566, ucf:52583
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007566
- Title
- Behavioral and disease ecology of Gopher Tortoises (Gopherus polyphemus) post exclusion and relocation with a novel approach to homing determination.
- Creator
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Napier, Johnathan, Savage, Anna, Moore, Sean, Vonkalm, Laurence, Fedorka, Kenneth, University of Central Florida
- Abstract / Description
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In the wake of human expansion, relocations and the loss of habitat can be stressful to an organism, plausibly leading to population declines. The gopher tortoise (Gopherus polyphemus) is a keystone species that constructs burrows it shares with 362 commensal species. Frequent exclusions and relocations and long generation times have contributed to G. polyphemus being State-designated as Threatened in Florida. Prior studies have indicated that G. polyphemus may possess homing behavior and...
Show moreIn the wake of human expansion, relocations and the loss of habitat can be stressful to an organism, plausibly leading to population declines. The gopher tortoise (Gopherus polyphemus) is a keystone species that constructs burrows it shares with 362 commensal species. Frequent exclusions and relocations and long generation times have contributed to G. polyphemus being State-designated as Threatened in Florida. Prior studies have indicated that G. polyphemus may possess homing behavior and thus be able to counteract stressors due to relocation and exclusion. I radiotracked a cohort of G. polyphemus for 11 months following excavation, relocation, and exclusion due to a pipeline construction project. In conjunction with analyzing G. polyphemus movement patterns post-release, I developed novel statistical methodologies with broad application for movement analysis and compared them to traditional analyses. I evaluated habitat usage, burrowing behavior, movements, growth, and disease signs among control versus relocated and excluded individuals and among sexes and size classes, forming predictors for behavior and disease risk. I found statistical support that my new methodology is superior to previous statistical tests for movement analyses. I also found that G. polyphemus engages in homing behavior, but only in males. Behavioral differences were also found between the sexes with respect to burrowing behavior. Overall health, disease prevalence, and immune response were unaffected by relocation and exclusion, nor were they statistically correlated. Signs were unreliable as etiological agents, outperformed by serological detection. I determined that the Sabal Trail pipeline as a potential stressor did not affect movement behavior, homing, nor the disease/immune profile of G. polyphemus in this study.
Show less - Date Issued
- 2018
- Identifier
- CFE0007581, ucf:52581
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007581
- Title
- Numerical Study of Interfacial flow using Algebraic Coupled Level Set-Volume of Fluid (A-CLSVOF) Method.
- Creator
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Haghshenas, Majid, Kumar, Ranganathan, Das, Tuhin, Ahmed, Kareem, Shivamoggi, Bhimsen, University of Central Florida
- Abstract / Description
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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 Driver Behavior Modeling in Connected Vehicle Safety Systems Through High Fidelity Simulation.
- Creator
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Jamialahmadi, Ahmad, Pourmohammadi Fallah, Yaser, Rahnavard, Nazanin, Chatterjee, Mainak, University of Central Florida
- Abstract / Description
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A critical aspect of connected vehicle safety analysis is understanding the impact of human behavior on the overall performance of the safety system. Given the variation in human driving behavior and the expectancy for high levels of performance, it is crucial for these systems to be flexible to various driving characteristics. However, design, testing, and evaluation of these active safety systems remain a challenging task, exacerbated by the lack of behavioral data and practical test...
Show moreA critical aspect of connected vehicle safety analysis is understanding the impact of human behavior on the overall performance of the safety system. Given the variation in human driving behavior and the expectancy for high levels of performance, it is crucial for these systems to be flexible to various driving characteristics. However, design, testing, and evaluation of these active safety systems remain a challenging task, exacerbated by the lack of behavioral data and practical test platforms. Additionally, the need for the operation of these systems in critical and dangerous situations makes the burden of their evaluation very costly and time-consuming. As an alternative option, researchers attempt to use simulation platforms to study and evaluate their algorithms. In this work, we introduce a high fidelity simulation platform, designed for a hybrid transportation system involving both human-driven and automated vehicles. We decompose the human driving task and offer a modular approach in simulating a large-scale traffic scenario, making it feasible for extensive studying of automated and active safety systems. Furthermore, we propose a human-interpretable driver model represented as a closed-loop feedback controller. For this model, we analyze a large driving dataset to extract expressive parameters that would best describe different driving characteristics. Finally, we recreate a similarly dense traffic scenario within our simulator and conduct a thorough analysis of different human-specific and system-specific factors and study their effect on the performance and safety of the traffic network.
Show less - Date Issued
- 2018
- Identifier
- CFE0007573, ucf:52578
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007573
- Title
- Help me be healthy: Perceptions of social support in an online weight loss program.
- Creator
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Davies, Brittany, Sandoval, Jennifer, Neuberger, Lindsay, Hastings, Sally, University of Central Florida
- Abstract / Description
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As technology changes, so do the ways in which we receive information, provide information and interact with one another. The exchange of social support is increasingly mediated by technology in the realm of health, nutrition, and fitness (Dahl, et al 2015; Wright et al 2011). Commercial weight loss and healthy lifestyle initiatives such as the Beachbody programs incorporate social media and web applications to reach a broader consumer base with individualized programming options. The present...
Show moreAs technology changes, so do the ways in which we receive information, provide information and interact with one another. The exchange of social support is increasingly mediated by technology in the realm of health, nutrition, and fitness (Dahl, et al 2015; Wright et al 2011). Commercial weight loss and healthy lifestyle initiatives such as the Beachbody programs incorporate social media and web applications to reach a broader consumer base with individualized programming options. The present study, guided by optimal matching theory and the helper theory principle, employed online participant-observation and in-depth, semi-structured interviews with Beachbody coaches and participants to investigate how these individuals perceived social support to be enacted in these programs as well as the perceived benefits and challenges of participating in these online groups. The interview transcripts were coded using thematic analysis to identify significant topics based on Owen's (1984) process of identifying recurrence, repetition, and forcefulness. Major benefits for participants included accountability, around the clock access to feedback, and access to a wide range of information. Noted challenges included the lack of personal connection and a need to maintain face-to-face relationships, difficulty sustaining motivation, and financial concerns. Cultivating a genuine feeling of community to facilitate open discussion and sharing was often inconsistent and a challenge to maintain throughout the duration of the program. This study aims to expand our understanding of social support in the context of online fitness and nutrition programs with potential to guide further research in technology-mediated support and how it may affect health. By broadening our understanding of the benefits of online support and how individuals have overcome its challenges in this context, it may help provide direction for the development of future research and similar online health initiatives.
Show less - Date Issued
- 2018
- Identifier
- CFE0007567, ucf:52574
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007567
- Title
- Vibration Reduction of Mistuned Bladed Disks via Piezoelectric-Based Resonance Frequency Detuning.
- Creator
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Lopp, Garrett, Kauffman, Jeffrey L., Das, Tuhin, Xu, Yunjun, University of Central Florida
- Abstract / Description
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Recent trends in turbomachinery blade technology have led to increased use of monolithically constructed bladed disks (blisks). Although offering a wealth of performance benefits, this construction removes the blade-attachment interface present in the conventional design, thus unintentionally removing a source of friction-based damping needed to counteract large vibrations during resonance passages. This issue is further exacerbated in the presence of blade mistuning that arises from small...
Show moreRecent trends in turbomachinery blade technology have led to increased use of monolithically constructed bladed disks (blisks). Although offering a wealth of performance benefits, this construction removes the blade-attachment interface present in the conventional design, thus unintentionally removing a source of friction-based damping needed to counteract large vibrations during resonance passages. This issue is further exacerbated in the presence of blade mistuning that arises from small imperfections from otherwise identical blades and are unavoidable as they originate from manufacturing tolerances and operational wear over the lifespan of the engine. Mistuning is known to induce vibration localization with large vibration amplitudes that render blades susceptible to failure induced by high-cycle fatigue. The resonance frequency detuning (RFD) method reduces vibration associated with resonance crossings by selectively altering the blades' structural response. This method utilizes the variable stiffness properties of piezoelectric materials to switch between available stiffness states at some optimal time as the excitation frequency sweeps through a resonance. For a single-degree-of-freedom (SDOF) system, RFD performance is well defined. This research provides the framework to extend RFD to more realistic applications when the SDOF assumption breaks down, such as in cases of blade mistuning. Mistuning is inherently random; thus, a Monte Carlo analysis performed on a computationally cheap lumped-parameter model provides insight into RFD performance for various test parameters. Application of a genetic algorithm reduces the computational expense required to identify the optimal set of stiffness-state switches. This research also develops a low-order blisk model with blade-mounted piezoelectric patches as a tractable first step to apply RFD to more realistic systems. Application of a multi-objective optimization algorithm produces Pareto fronts that aid in the selection of the optimized patch parameters. Experimental tests utilizing the academic blisk with the optimized patches provides validation.
Show less - Date Issued
- 2018
- Identifier
- CFE0007488, ucf:52639
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007488
- Title
- Exploring a Three-Dimensional Narrative Medium: The Theme Park as "De Sprookjessprokkelaar," The Gatherer and Teller of Stories.
- Creator
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Baker, Carissa, McDaniel, Rudy, Salter, Anastasia, Underberg-Goode, Natalie, Hover, Moniek, Dickson, Duncan, University of Central Florida
- Abstract / Description
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This dissertation examines the pervasiveness of storytelling in theme parks and establishes the theme park as a distinct narrative medium. It traces the characteristics of theme park storytelling, how it has changed over time, and what makes the medium unique. This was accomplished using a mixed methods approach drawing data from interviews with creative professionals, archival research, fieldwork, and an analysis of more than eight hundred narrative attractions.The survey of narrative...
Show moreThis dissertation examines the pervasiveness of storytelling in theme parks and establishes the theme park as a distinct narrative medium. It traces the characteristics of theme park storytelling, how it has changed over time, and what makes the medium unique. This was accomplished using a mixed methods approach drawing data from interviews with creative professionals, archival research, fieldwork, and an analysis of more than eight hundred narrative attractions.The survey of narrative attractions revealed the most common narrative expressions to be dark rides and stage shows. Source material tends to be cultural tales (legends, fairy tales) or intellectual properties (generally films). Throughout major periods and world regions, setting, scenes, and visual storytelling are the most ubiquitous narrative devices. Three dozen techniques and technologies are detailed in this project. Significant impetuses for narrative change over time are the advent of technologies, formalization of the industry, explicit discourse on storytelling, formation of design philosophies, and general convergence of media. There are at least a half dozen key distinctions in theme park narratives compared with other mediums: dimensionality, scale, communality, brevity, a combinatory aspect, and a reiterative nature. Also significant is that creative professionals view themselves as storytellers, purposefully design with narrative systems, embed them in spaces, and participate in public dialogue surrounding narrative and design principles.This study was initiated to expand the literature on emerging media and narratives within the Texts and Technology approach and to fill a gap in the scholarship, as designer standpoint is rarely considered in analysis. This is the first large-scale study of storytelling in the global theme park industry. It uses underrepresented creative voices as participants and recognizes their contributions as storytellers. Finally, the project lays the groundwork for future inquiries into theme parks as storytellers and spatial narrative mediums.
Show less - Date Issued
- 2018
- Identifier
- CFE0006973, ucf:51626
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006973
- Title
- Dynamic Hotspot Identification for Limited Access Facilities using Temporal Traffic Data.
- Creator
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Al Amili, Samer, Abdel-Aty, Mohamed, Radwan, Essam, Eluru, Naveen, Lee, JaeYoung, Wang, Chung-Ching, University of Central Florida
- Abstract / Description
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Crash frequency analysis is the most critical tool to investigate traffic safety problems. Therefore, an accurate crash analysis must be conducted. Since traffic continually fluctuates over time and this effects potential of crash occurrence, shorter time periods and less aggregated traffic factors (shorter intervals than AADT) need to be used. In this dissertation, several methodologies have been conducted to elevate the accuracy of crash prediction. The performance of using less aggregated...
Show moreCrash frequency analysis is the most critical tool to investigate traffic safety problems. Therefore, an accurate crash analysis must be conducted. Since traffic continually fluctuates over time and this effects potential of crash occurrence, shorter time periods and less aggregated traffic factors (shorter intervals than AADT) need to be used. In this dissertation, several methodologies have been conducted to elevate the accuracy of crash prediction. The performance of using less aggregated traffic data in modeling crash frequency was explored for weekdays and weekends. Four-time periods for weekdays and two time periods for weekends, with four intervals (5, 15, 30, and 60 minutes). The comparison between AADT based models and short-term period models showed that short-term period models perform better. As a shorter traffic interval than AADT considered, two difficulties began. Firstly, the number of zero observations increased. Secondly, the repetition of the same roadway characteristics arose. To reduce the number of zero observations, only segments with one or more crashes were used in the modeling process. To eliminate the effect of the repetition in the data, random effect was applied. The results recommend adopting segments with only one or more crashes, as they give a more valid prediction and less error.Zero-inflated negative binomial (ZINB) and hurdle negative binomial (HNB) models were examined in addition to the negative binomial for both weekdays and weekends. Different implementations of random effects were applied. Using the random effect either on the count part, on the zero part, or a pair of uncorrelated (or correlated) random effects for both parts of the model. Additionally, the adaptive Gaussian Quadrature, with five quadrature points, was used to increase accuracy. The results reveal that the model which considered the random effect in both parts performed better than other models, and ZINB performed better than HNB.
Show less - Date Issued
- 2018
- Identifier
- CFE0006966, ucf:51682
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006966
- Title
- A Single Case Study on the Influence of Feedback on the Instructional Quality of a Preservice Elementary Teacher in Mathematics: The Instructional Quality Assessment Toolkit as a Resource.
- Creator
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Campbell Sutherland, Makini, Dixon, Juli, Safi, Farshid, Hoffman, Elizabeth, Andreasen, Janet, Childs, Kristopher, University of Central Florida
- Abstract / Description
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The purpose of this single case study was to determine if a preservice elementary teacher's instruction would be influenced by feedback on mathematics lessons. The focus of the research was on the use of the Instructional Quality Assessment (IQA) (Boston 2012) toolkit as an integral part in the feedback process. The IQA toolkit provides number ratings as well as qualitative descriptive ratings of various aspects of the mathematics lesson, defined under two constructs, or groups, labeled...
Show moreThe purpose of this single case study was to determine if a preservice elementary teacher's instruction would be influenced by feedback on mathematics lessons. The focus of the research was on the use of the Instructional Quality Assessment (IQA) (Boston 2012) toolkit as an integral part in the feedback process. The IQA toolkit provides number ratings as well as qualitative descriptive ratings of various aspects of the mathematics lesson, defined under two constructs, or groups, labeled Academic Rigor and Accountable Talk. The researcher evaluated a preservice teacher's instruction on three occasions and facilitated feedback sessions following those observation sessions, integrating the number ratings of the IQA toolkit with the qualitative descriptions of expectations. It was found that there was an increase in ratings for both constructs of Academic Rigor and Accountable Talk over the period of three feedback cycles. There was a difference in how the students were facilitated in instruction over the three observations. The teacher became more aware of some of her behaviors in the classroom that contributed to the type of instruction given to students.In reviewing the literature, there was limited evidence of the use of the IQA toolkit for the iterative process of teaching, feedback, and teaching informed by feedback. This research is therefore useful in expanding the use of the IQA toolkit for feedback purposes. Preservice teachers as well as in-service teachers can benefit from feedback focused on mathematics teaching that makes them more aware of their strengths and weaknesses so they are able to adjust instruction based on the feedback received.
Show less - Date Issued
- 2018
- Identifier
- CFE0006983, ucf:51679
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006983
