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Title: Heat Transfer in a Coupled Impingement-Effusion Cooling System.
Creator: Miller, Mark, Kapat, Jayanta, Deng, Weiwei, Gordon, Ali, University of Central Florida
Abstract / Description: The efficiency of air-breathing gas turbine engines improves as the combustion temperature increases. Therefore, modern gas turbines operate at temperatures greater than the melting temperature of hot-gas-path components, and cooling must be introduced in order to maintain mechanical integrity of those components. Two highly effective techniques used in modern designs for this purpose are impingement cooling and use of coolant film on hot-gas-path surface introduced through discrete film or...
Show moreThe efficiency of air-breathing gas turbine engines improves as the combustion temperature increases. Therefore, modern gas turbines operate at temperatures greater than the melting temperature of hot-gas-path components, and cooling must be introduced in order to maintain mechanical integrity of those components. Two highly effective techniques used in modern designs for this purpose are impingement cooling and use of coolant film on hot-gas-path surface introduced through discrete film or effusion holes. In this study, these two mechanisms are coupled into a single prototype cooling system. The heat transfer capability of this system is experimentally determined for a variety of different geometries and coolant flow rates.This study utilizes Temperature Sensitive Paint (TSP) in order to measure temperature distribution over a surface, which allowed for local impingement Nusselt number, film cooling effectiveness, and film cooling heat transfer enhancement profiles to be obtained. In addition to providing quantitative heat transfer data, this method allowed for qualitative investigation of the flow behavior near the test surface. Impinging jet-to-target-plate spacing was varied over a large range, including several tall impingement scenarios outside the published limits. Additionally, both in-line and staggered effusion arrangements were studied, and results for normal injection were compared to full coverage film cooling with inclined- and compound-angle injection. Effects of impingement and effusion cooling were combined to determine the overall cooling effectiveness of the system.It is shown that low impingement heights produce the highest Nusselt number, and that large jet-to-jet spacing reduces coolant flow rate while maintaining moderate to high heat transfer rates. Staggered effusion configurations exhibit superior performance to in-line configurations, as jet interference is reduced and surface area coverage is improved. Coolant to mainstream flow mass flux ratios greater than unity result in jet blow-off and reduced effectiveness. The convective heat transfer coefficient on the film cooled surface is higher than a similar surface without coolant injection due to the generation of turbulence associated with jet-cross flow interaction.
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Date Issued: 2011
Identifier: CFE0004140, ucf:49042
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004140

Title: CO Florida 2012, A MOVES-Based, Near-Road, Screening Model.
Creator: Ritner, Mark, Cooper, Charles, Radwan, Ahmed, Randall, Andrew, University of Central Florida
Abstract / Description: Citizens in the United States are fortunate to have an excellent system of roadways and the affluence with which to afford automobiles. The flexibility of travel on demand for most allows for a variety of lifestyles, assists with conducting business, and contributes to the feeling of freedom that most citizens enjoy. The current vehicle fleet, which is primarily powered by internal combustion engines burning fossil fuels, does however contribute to the deterioration of air quality. This...
Show moreCitizens in the United States are fortunate to have an excellent system of roadways and the affluence with which to afford automobiles. The flexibility of travel on demand for most allows for a variety of lifestyles, assists with conducting business, and contributes to the feeling of freedom that most citizens enjoy. The current vehicle fleet, which is primarily powered by internal combustion engines burning fossil fuels, does however contribute to the deterioration of air quality. This effect is particularly significant in metropolitan areas. Motor vehicle exhausts contain several combustion bi-products that pose harmful effects to the environment and human health, in particular. The United States Environmental Protection Agency (EPA) and the Federal Highway Administration (FHWA) have selected carbon monoxide (CO) as the air pollutant on which it has based its guidelines for assessing potential air quality impacts from roadway construction (EPA 1992).The design of roadway networks must consider traffic flows, Level of Service (LOS), cost, and National Ambient Air Quality Standards (NAAQS) requirements. In light of the environmental standards it is necessary to model to estimate potential future near-road concentrations of CO. This modeling has two aspects, first determining the rate of pollutant emissions, and second determining how those pollutants disperse near the road. Obtaining a precise, realistic estimate of the near-road CO concentrations under a wide variety of weather and traffic patterns is a potentially huge undertaking. With budgetary constraints in mind, the development of a screening model is appropriate. CO Florida 2012 (COFL2012) is such a model that uses conservative assumptions to predict worst-case, near-road CO concentration. Projects that pass a COFL2012 model run do not require additional air quality modeling. Projects that fail a COFL2012 model run, however, may still be viable, but will require additional, detailed modeling and possibly project modifications.COFL2012 uses tables of emission factors (EFs) that were derived from numerous runs of the EPA's MOtor Vehicle Emission Simulator (MOVES2010a), which is indicated as the preferred model for near-road modeling of CO.(EPA 2009) COFL2012 then inputs the EFs, along with assumed link configurations, geographical assumptions, and user-inputted traffic information into input files that are run through CAL3QHC Version 2.0 (CAL3QHC2), the EPA's approved near-road dispersion model (EPA 1995).COFL2012 is a brand new Florida CO screening model, written from scratch. This author has written the computer code for COFL2012 in Visual Basic, using Microsoft Visual Studios 2010. Visual Studios utilizes the .net Framework 4. COFL2012 is easy to learn, quick to operate, and has been written to allow for future updates simply and easily, whenever the EPA releases updates to the databases that feed MOVES2010a.
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Date Issued: 2012
Identifier: CFE0004233, ucf:49011
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004233

Title: The Effect of Magnetic Bearing on the Vibration and Friction of a Wind Turbine.
Creator: Vorwaller, Mark, Lin, Kuo-Chi, Raghavan, Seetha, Gou, Jihua, University of Central Florida
Abstract / Description: Demands for sustainable energy have resulted in increased interest in wind turbines. Thus, despite widespread economic difficulties, global installed wind power increased by over 20% in 2011 alone. Recently, magnetic bearing technology has been proposed to improve wind turbine performance by mitigating vibration and reducing frictional losses. While magnetic bearing has been shown to reduce friction in other applications, little data has been presented to establish its effect on vibration and...
Show moreDemands for sustainable energy have resulted in increased interest in wind turbines. Thus, despite widespread economic difficulties, global installed wind power increased by over 20% in 2011 alone. Recently, magnetic bearing technology has been proposed to improve wind turbine performance by mitigating vibration and reducing frictional losses. While magnetic bearing has been shown to reduce friction in other applications, little data has been presented to establish its effect on vibration and friction in wind turbines. Accordingly, this study provides a functional method for experimentally evaluating the effect of a magnetic bearing on the vibration and efficiency characteristics of a wind turbine, along with associated results and conclusions.The magnetic bearing under examination is a passive, concentric ring design. Vibration levels, dominant frequency components, and efficiency results are reported for the bearing as tested in two systems: a precision test fixture, and a small commercially available wind turbine. Data is also presented for a geometrically equivalent ball bearing, providing a benchmark for the magnetic bearing's performance. The magnetic bearing is conclusively shown to reduce frictional losses as predicted by the original hypothesis. However, while reducing vibration in the precision test fixture, the magnetic bearing demonstrates increased vibration in the small wind turbine. This is explained in terms of the stiffness and damping of the passive test bearing. Thus, magnetic bearing technology promises to improve wind turbine performance, provided that application specific stiffness and damping characteristics are considered in the bearing design.
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Date Issued: 2012
Identifier: CFE0004452, ucf:49326
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004452

Title: The Path of Least Resistance: The Failure of Humanitarianism and American Foreign Policy in Sudan.
Creator: MacFarlane, Mark, Walker, Ezekiel, Crepeau, Richard, Herlihy, Kevin, University of Central Florida
Abstract / Description: This thesis examines America's response to civil war, dispossession, and humanitarian disaster in Sudan from the end of the Cold War up until the second Darfur uprising. While the number of scholarly works examining the overall conflict and humanitarian crisis are immense, less has been written in regard to America's foreign policy in Sudan. The contemporary nature of the crisis and dearth of historical analysis does make establishing trends difficult; but recent works suggest a U.S. policy...
Show moreThis thesis examines America's response to civil war, dispossession, and humanitarian disaster in Sudan from the end of the Cold War up until the second Darfur uprising. While the number of scholarly works examining the overall conflict and humanitarian crisis are immense, less has been written in regard to America's foreign policy in Sudan. The contemporary nature of the crisis and dearth of historical analysis does make establishing trends difficult; but recent works suggest a U.S. policy that is ill informed and therefore ineffectual in halting both the conflict and crisis in Sudan. However, contrary to this opinion, the evidence may demonstrate that United States policy, rather than a series of misjudgments or being simply ineffectual, has been more systematic, informed and purposeful. This thesis argues that while the United States wished for peace in Sudan, the historical evidence suggests that the path taken by the United States knowingly prolonged the suffering of millions of Sudanese. Furthermore, American policy makers have entrusted peace in Darfur and in other disparate regions of Sudan, as well as along the newly formed borders with South Sudan, to the National Congress Party (NCP) a regime Congress has labeled untrustworthy and despotic. The bulk of the research used in this examination covered the period from 1989- 2008. However, the independence achieved by the Republic of South Sudan in the summer of 2011 is taken into account in the final analysis of the thesis. The secondary sources both cited and considered for the thesis were substantial; these included academic articles, studies, and texts published over several decades in several related fields of study germane to the thesis topic. While a wide range of primary sources were used, the thesis relied heavily on United States Congressional records from 1989-2008 for analysis. ?
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Date Issued: 2012
Identifier: CFE0004247, ucf:49536
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004247

Title: Decentralized Consensus-based Control Allocation For Some Dynamical Systems.
Creator: Mark, August, Xu, Yunjun, Gou, Jihua, Lin, Kuo-Chi, University of Central Florida
Abstract / Description: In this dissertation, three separate studies, wherein techniques from graph theory and consensus control are used to address control allocation problems, are presented. In the first study, a decentralized allocator is presented for synthetic jet actuators and control surfaces onboard a small unmanned aerial vehicle to cooperatively generate desired aerodynamic moments. First order linear dynamics are assumed for both the synthetic jet actuators and control surfaces. A weighted consensus...
Show moreIn this dissertation, three separate studies, wherein techniques from graph theory and consensus control are used to address control allocation problems, are presented. In the first study, a decentralized allocator is presented for synthetic jet actuators and control surfaces onboard a small unmanned aerial vehicle to cooperatively generate desired aerodynamic moments. First order linear dynamics are assumed for both the synthetic jet actuators and control surfaces. A weighted consensus algorithm with limited feedback is used for the aerodynamic moment contribution allocator considering constraints. In the second study, the same allocation problem as in the first study is considered, but the actuator dynamics are now assumed to behave according to second order nonlinear dynamics. In the third study, a spray allocator is presented for an array of nozzles used to cool a large heated surface in order to address the local disagreement in surface temperature within sprayed sections. Within each study, the stability of each system is proven, and the performance of each allocator is demonstrated via simulations.
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Date Issued: 2019
Identifier: CFE0007496, ucf:52636
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007496

Title: Providing Cultural Balance for Young Americans.
Creator: Nichols, Mark, Listengarten, Julia, Rusnock, Joseph, Scott, Bert, University of Central Florida
Abstract / Description: Children today are increasingly being introduced to tablets and other personal electronic devices at very young ages. Due in part to this, the entertainment industry now has a near ubiquitous presence in America compared to cultural arts. Its influence on the development of children is almost impossible to ignore. My thesis will study an approach to engaging young people by way of location-based projects that synthesize two or more art forms (e.g. theatre arts, literary arts, visual arts) in...
Show moreChildren today are increasingly being introduced to tablets and other personal electronic devices at very young ages. Due in part to this, the entertainment industry now has a near ubiquitous presence in America compared to cultural arts. Its influence on the development of children is almost impossible to ignore. My thesis will study an approach to engaging young people by way of location-based projects that synthesize two or more art forms (e.g. theatre arts, literary arts, visual arts) in order to provide a unified effort for cultural arts and also provide balance to the influences of entertainment. Incorporating research, interviews with people instrumental in the creation of this approach, and analysis of the data, I intend to answer several essential research questions: What are the pros and cons of creating and/or operating these collaborative cultural arts facilities? Are recently created collaborative cultural arts centers, nationally and internationally (e.g. ImaginOn in Charlotte, NC) successfully addressing the imbalance of cultural influence and if so, in what way? What are the conditions and steps required to create a collaborative cultural arts facility and replicate a model similar to Charlotte's ImaginOn in other cities in the United States?
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Date Issued: 2015
Identifier: CFE0006047, ucf:50965
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006047

Title: Deposition Thickness Modeling and Parameter Identification for Spray Assisted Vacuum Filtration Process in Additive Manufacturing.
Creator: Mark, August, Xu, Yunjun, Gou, Jihua, Lin, Kuo-Chi, University of Central Florida
Abstract / Description: To enhance mechanical and/or electrical properties of composite materials used in additive manufacturing, nanoparticles are often time deposited to form nanocomposite layers. To customize the mechanical and/or electrical properties, the thickness of such nanocomposite layers must be precisely controlled. A thickness model of filter cakes created through a spray assisted vacuum filtration is presented in this paper, to enable the development of advanced thickness controllers. The mass transfer...
Show moreTo enhance mechanical and/or electrical properties of composite materials used in additive manufacturing, nanoparticles are often time deposited to form nanocomposite layers. To customize the mechanical and/or electrical properties, the thickness of such nanocomposite layers must be precisely controlled. A thickness model of filter cakes created through a spray assisted vacuum filtration is presented in this paper, to enable the development of advanced thickness controllers. The mass transfer dynamics in the spray atomization and vacuum filtration are studied for the mass of solid particles and mass of water in differential areas, and then the thickness of a filter cake is derived. A two-loop nonlinear constrained optimization approach is used to identify the unknown parameters in the model. Experiments involving depositing carbon nanofibers in a sheet of paper are used to measure the ability of the model to mimic the filtration process.
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Date Issued: 2015
Identifier: CFE0005974, ucf:50788
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005974

Title: A New Path Planning Guidance Law For Improved Impact Time Control of Missiles and Precision Munitions.
Creator: Snyder, Mark, Qu, Zhihua, Haralambous, Michael, Xu, Yunjun, University of Central Florida
Abstract / Description: A new missile guidance law is proposed for the control of impact time which provides an improved time-to-go calculation by removing error due to trajectory curvature and also provides a family of trajectories for trajectory planning purposes. Unlike conventional optimal guidance laws, the proposed law is non explicit in time-to-go and the linearization of the engagement kinematics in order to gain a closed form solution is not necessary.
Date Issued: 2016
Identifier: CFE0006398, ucf:51506
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006398

Title: Re-Conceptualizing Compassion Fatigue: A Confirmatory Factor Analysis.
Creator: Marks, Madeline, Bowers, Clint, Beidel, Deborah, Jentsch, Florian, University of Central Florida
Abstract / Description: Those who are not directly in danger themselves can and do experience negative effects, sometimes at higher rates than those directly exposed. These individuals who experience indirect exposure are often those who work in (")helping(") professions. Helping professionals include psychologists, physicians, nurses, social workers, and first responders, among others. Joinson (1992) described a phenomenon unique to helping professionals, which was termed compassion fatigue. Compassion fatigue...
Show moreThose who are not directly in danger themselves can and do experience negative effects, sometimes at higher rates than those directly exposed. These individuals who experience indirect exposure are often those who work in (")helping(") professions. Helping professionals include psychologists, physicians, nurses, social workers, and first responders, among others. Joinson (1992) described a phenomenon unique to helping professionals, which was termed compassion fatigue. Compassion fatigue describes these negative affects experienced by helping professionals as a cumulative process. These negative changes can be related to mood and/or a transformation in cognitions. Further, these changes are the result of the empathy and emotionally intense contact with people who experienced a traumatic event, which results in maladaptive psychological consequences that influence the ability to perform the role of a (")helper(") (Bride, Robinson, Yegidis, (&) Figley, 2004; Figley, 1995; McCann (&) Pearlman, 1990; McHolm, 2006; Pearlman (&) Saakvitne, 1995; Stamm, 1995). To measure compassion fatigue, the Professional Quality of Life Scale (Stamm, 2005, 2010) has emerged as the most widely used assessment of compassion fatigue. However, not enough theoretical information and psychometric data on the ProQOL exist to support compassion fatigue as the construct to explain the experiences of those in helping professions. The present study examines the most widely used measure of compassion fatigue, the Professional Quality of Life Scale (ProQOL-5; Stamm, 2010). Specifically, the current study examines the factor validity of the ProQOL-5 using confirmatory factor analysis. In light of the lack of model fit, the construct of compassion fatigue offers a unique and worthy view of the negative consequences of helping others. As a result, the current study proposes a novel approach to clarify a method for measurement and clear-up conceptual overlaps between related constructs. This novel method uses the framework of the information processing model of Whiting (1969).
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Date Issued: 2016
Identifier: CFE0006475, ucf:51434
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006475

Title: Microscopic Assessment of Transportation Emissions on Limited Access Highways.
Creator: Abou-Senna, Hatem, Radwan, Ahmed, Abdel-Aty, Mohamed, Al-Deek, Haitham, Cooper, Charles, Johnson, Mark, University of Central Florida
Abstract / Description: On-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have...
Show moreOn-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have estimated emissions using one average speed and volume on a long stretch of roadway. With MOVES, there is an opportunity for higher precision and accuracy. Integrating a microscopic traffic simulation model (such as VISSIM) with MOVES allows one to obtain precise and accurate emissions estimates. The new United States Environmental Protection Agency (USEPA) mobile source emissions model, MOVES2010a (MOVES) can estimate vehicle emissions on a second-by-second basis creating the opportunity to develop new software (")VIMIS 1.0(") (VISSIM/MOVES Integration Software) to facilitate the integration process. This research presents a microscopic examination of five key transportation parameters (traffic volume, speed, truck percentage, road grade and temperature) on a 10-mile stretch of Interstate 4 (I-4) test bed prototype; an urban limited access highway corridor in Orlando, Florida. The analysis was conducted utilizing VIMIS 1.0 and using an advanced custom design technique; D-Optimality and I-Optimality criteria, to identify active factors and to ensure precision in estimating the regression coefficients as well as the response variable.The analysis of the experiment identified the optimal settings of the key factors and resulted in the development of Micro-TEM (Microscopic Transportation Emissions Meta-Model). The main purpose of Micro-TEM is to serve as a substitute model for predicting transportation emissions on limited access highways to an acceptable degree of accuracy in lieu of running simulations using a traffic model and integrating the results in an emissions model. Furthermore, significant emission rate reductions were observed from the experiment on the modeled corridor especially for speeds between 55 and 60 mph while maintaining up to 80% and 90% of the freeway's capacity. However, vehicle activity characterization in terms of speed was shown to have a significant impact on the emission estimation approach.Four different approaches were further examined to capture the environmental impacts of vehicular operations on the modeled test bed prototype. First, (at the most basic level), emissions were estimated for the entire 10-mile section (")by hand(") using one average traffic volume and average speed. Then, three advanced levels of detail were studied using VISSIM/MOVES to analyze smaller links: average speeds and volumes (AVG), second-by-second link driving schedules (LDS), and second-by-second operating mode distributions (OPMODE). This research analyzed how the various approaches affect predicted emissions of CO, NOx, PM and CO2. The results demonstrated that obtaining accurate and comprehensive operating mode distributions on a second-by-second basis improves emission estimates. Specifically, emission rates were found to be highly sensitive to stop-and-go traffic and the associated driving cycles of acceleration, deceleration, frequent braking/coasting and idling. Using the AVG or LDS approach may overestimate or underestimate emissions, respectively, compared to an operating mode distribution approach.Additionally, model applications and mitigation scenarios were examined on the modeled corridor to evaluate the environmental impacts in terms of vehicular emissions and at the same time validate the developed model (")Micro-TEM("). Mitigation scenarios included the future implementation of managed lanes (ML) along with the general use lanes (GUL) on the I-4 corridor, the currently implemented variable speed limits (VSL) scenario as well as a hypothetical restricted truck lane (RTL) scenario. Results of the mitigation scenarios showed an overall speed improvement on the corridor which resulted in overall reduction in emissions and emission rates when compared to the existing condition (EX) scenario and specifically on link by link basis for the RTL scenario.The proposed emission rate estimation process also can be extended to gridded emissions for ozone modeling, or to localized air quality dispersion modeling, where temporal and spatial resolution of emissions is essential to predict the concentration of pollutants near roadways.
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Date Issued: 2012
Identifier: CFE0004777, ucf:49788
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004777

Title: Measuring Player Perceptions of Freedom and Control in Modded and Unmodded Versions of Bethesda's Skyrim: A Qualitative Play Study.
Creator: Kretzschmar, Mark, Salter, Anastasia, Stanfill, Mel, Janz, Bruce, Postigo, Hector, University of Central Florida
Abstract / Description: This interdisciplinary dissertation explores perceptions of control in modded and unmodded versions of Bethesda's sandbox video game Skyrim. Sandbox games are known for greater choice options that suggest greater perceptions of control for gamers. Sandbox games also generally encourage the use of user-generated creations called modifications (mods) that users can download to personalize their games. While we need philosophy to understand and define control as a concept, we also need...
Show moreThis interdisciplinary dissertation explores perceptions of control in modded and unmodded versions of Bethesda's sandbox video game Skyrim. Sandbox games are known for greater choice options that suggest greater perceptions of control for gamers. Sandbox games also generally encourage the use of user-generated creations called modifications (mods) that users can download to personalize their games. While we need philosophy to understand and define control as a concept, we also need psychology to understand how users perceive control in media studies. At present, qualitative academic research that measures gamer perceptions of control is non-existent as is research on how users articulate their experiences with mods. Interviews were conducted with twenty-seven individuals who identified as gamers to analyze these perceptions of control in a game like Skyrim. The first chapter is introductory and outlines key terms for the dissertation as well as the play study's methodology. The second chapter examines philosophical and psychological perceptions of control that correspond with negative freedom (freedom from) and positive freedom (freedom to). While no game can promise radical free will because they have been programmed in advance, the information here may be used to demonstrate how perceptions of control might influence game design. The third chapter continues this exploration of perceived control through genre analysis, revealing the relationship between greater perceptions of control and mod support in sandbox video games. The fourth chapter presents the first two findings from the play study that demonstrate how mods influence player perceptions of control. The fifth chapter reveals how gamers of the play study discuss their perceptions of control video games in their own words with an emphasis on positive and negative freedom and generic conventions. The final chapter provides challenges for game design and scholarly qualitative analysis for future research based on findings in the play study.
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Date Issued: 2019
Identifier: CFE0007479, ucf:52673
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007479

Title: The Hermeneutics of the Hard Drive: Using Narratology, Natural Language Processing, and Knowledge Management to Improve the Effectiveness of the Digital Forensic Process.
Creator: Pollitt, Mark, Applen, John, Bowdon, Melody, Dombrowski, Paul, Craiger, John, University of Central Florida
Abstract / Description: In order to protect the safety of our citizens and to ensure a civil society, we ask our law enforcement, judiciary and intelligence agencies, under the rule of law, to seek probative information which can be acted upon for the common good. This information may be used in court to prosecute criminals or it can be used to conduct offensive or defensive operations to protect our national security. As the citizens of the world store more and more information in digital form, and as they live an...
Show moreIn order to protect the safety of our citizens and to ensure a civil society, we ask our law enforcement, judiciary and intelligence agencies, under the rule of law, to seek probative information which can be acted upon for the common good. This information may be used in court to prosecute criminals or it can be used to conduct offensive or defensive operations to protect our national security. As the citizens of the world store more and more information in digital form, and as they live an ever-greater portion of their lives online, law enforcement, the judiciary and the Intelligence Community will continue to struggle with finding, extracting and understanding the data stored on computers. But this trend affords greater opportunity for law enforcement. This dissertation describes how several disparate approaches: knowledge management, content analysis, narratology, and natural language processing, can be combined in an interdisciplinary way to positively impact the growing difficulty of developing useful, actionable intelligence from the ever-increasing corpus of digital evidence. After exploring how these techniques might apply to the digital forensic process, I will suggest two new theoretical constructs, the Hermeneutic Theory of Digital Forensics and the Narrative Theory of Digital Forensics, linking existing theories of forensic science, knowledge management, content analysis, narratology, and natural language processing together in order to identify and extract narratives from digital evidence. An experimental approach will be described and prototyped. The results of these experiments demonstrate the potential of natural language processing techniques to digital forensics.
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Date Issued: 2013
Identifier: CFE0005112, ucf:50749
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005112

Title: Ultrafast Laser Material Processing For Photonic Applications.
Creator: Ramme, Mark, Richardson, Martin, Fathpour, Sasan, Sundaram, Kalpathy, Kar, Aravinda, University of Central Florida
Abstract / Description: Femtosecond Laser Direct Writing (FLDW) is a viable technique for producing photonic devices in bulk materials. This novel manufacturing technique is versatile due to its full 3D fabrication capability. Typically, the only requirement for this process is that the base material must be transparent to the laser wavelength. The modification process itself is based on non-linear energy absorption of laser light within the focal volume of the incident beam.This thesis addresses the feasibility of...
Show moreFemtosecond Laser Direct Writing (FLDW) is a viable technique for producing photonic devices in bulk materials. This novel manufacturing technique is versatile due to its full 3D fabrication capability. Typically, the only requirement for this process is that the base material must be transparent to the laser wavelength. The modification process itself is based on non-linear energy absorption of laser light within the focal volume of the incident beam.This thesis addresses the feasibility of this technique for introducing photonic structures into novel dielectric materials. Additionally, this work provides a deeper understanding of the light-matter interaction mechanism occurring at high pulse repetition rates. A novel structure on the sample surface in the form of nano-fibers was observed when the bulk material was irradiated with high repetition rate pulse trains.To utilize the advantages of the FLDW technique even further, a transfer of the technology from dielectric to semiconductor materials is investigated. However, this demands detailed insight of the absorption and modification processes themselves. Experiments and the results suggested that non-linear absorption, specifically avalanche ionization, is the limiting factor inhibiting the application of FLDW to bulk semiconductors with today's laser sources.
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Date Issued: 2013
Identifier: CFE0004914, ucf:49626
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004914

Title: Design, Fabrication, and Interrogation of Integrated Wireless SAW Temperature Sensors.
Creator: Gallagher, Mark, Malocha, Donald, Richie, Samuel, Weeks, Arthur, Youngquist, Robert, Delfyett, Peter, University of Central Florida
Abstract / Description: Wireless surface acoustic wave (SAW) sensors offer unique advantages over other sensor technologies because of their inherent ability to operate in harsh environments and completely passive operation, providing a reliable, maintenance-free life cycle. For certain SAW sensor applications the challenge is building a wirelessly interrogatable device with the same lifetime as the SAW substrate. The design of these application intensive sensors is complicated by the degradation of device bond...
Show moreWireless surface acoustic wave (SAW) sensors offer unique advantages over other sensor technologies because of their inherent ability to operate in harsh environments and completely passive operation, providing a reliable, maintenance-free life cycle. For certain SAW sensor applications the challenge is building a wirelessly interrogatable device with the same lifetime as the SAW substrate. The design of these application intensive sensors is complicated by the degradation of device bond wires, die adhesive, and antenna substrate. In an effort to maximize the benefits of the platform, this dissertation demonstrates wafer-level integrated SAW sensors that directly connect the thin film SAW to a thick film on-wafer antenna. Fully integrated device embodiments are presented that operate over a wide range of temperatures using different fabrication techniques, substrates, and coding principles.
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Date Issued: 2015
Identifier: CFE0005795, ucf:50047
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005795

Title: Through the Eyes of First-Year College Students: The Importance of Trust in the Development of Effective Advising Relationships.
Creator: Lemon, Mark, Cintron Delgado, Rosa, Boyd, Tammy, Owens, James, Beverly, Monifa, Laureano Fuentes, Gloria, University of Central Florida
Abstract / Description: This research was conducted to better understand how first-year college students make sense of the role of trust in the development of the relationship with their academic advisors and how they characterize the conditions that enhance or hinder trust in this relationship. An extensive literature review was conducted, identifying relevant scholarship concerning trust and academic advising--the history, philosophy, and professionalization of the field. Also, a brief section on distrust was...
Show moreThis research was conducted to better understand how first-year college students make sense of the role of trust in the development of the relationship with their academic advisors and how they characterize the conditions that enhance or hinder trust in this relationship. An extensive literature review was conducted, identifying relevant scholarship concerning trust and academic advising--the history, philosophy, and professionalization of the field. Also, a brief section on distrust was presented to offer balance in the trust literature and to support the Lewicki, McAllister, (&) Bies' (1998) theoretical framework that guided this research endeavor. Moreover, a profile of the traditional, first-year college student was introduced, as this distinct population was asked to participate in this study and to share their unique lived experiences, detailing the relationships they have developed with their academic advisors. A phenomenological research design was employed, collecting participant data via in-depth interviews, an advisor/trust orientation exercise, and member checking. After these data were collected, the Moustakas (1994) four-step approach to data analysis was utilized as a means of data reduction. Eight traditional, first-year college students participated in this research endeavor, and all indicated that the role of trust was important in the development of the relationship with their academic advisors. Also, they isolated four trust characteristics that may enhance trust in their advising relationships: initiative, knowledge/expertise, kindness, and reliability. Likewise, the inverse of these named trust facets may hinder trust in their advising relationships. These new discoveries offer powerful insights for advancing the field of collegiate level academic advising.
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Date Issued: 2013
Identifier: CFE0005022, ucf:49984
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005022

Title: Analysis of the Congruency between Educational Choices and Community College Student Degree Aspirations.
Creator: Quathamer, Mark, Owens, J. Thomas, Cintron Delgado, Rosa, Cox, Thomas, Marshall, Nancy, LAMB, ROBERT, University of Central Florida
Abstract / Description: This research explored variables that influence community college student degree aspirations and students purpose for enrolling and pursuing specific degree types. The study was conducted using secondary data for students pursuing Associate in Arts, Associate in Science, and Bachelor of Applied Science degrees at a single community college. A logistic regression test was used to test graduate and baccalaureate degree aspirations of the entire sample of students and separately by degree type....
Show moreThis research explored variables that influence community college student degree aspirations and students purpose for enrolling and pursuing specific degree types. The study was conducted using secondary data for students pursuing Associate in Arts, Associate in Science, and Bachelor of Applied Science degrees at a single community college. A logistic regression test was used to test graduate and baccalaureate degree aspirations of the entire sample of students and separately by degree type. Significant predictors of degree aspirations included age, gender, credits enrolled in, participation in student groups, academic course planning, receipt of scholarship, and college GPA. In general, community college students had high degree aspirations. Younger students tended to be on the collegiate transfer track and older students tended to want to pursue baccalaureate degrees locally. In addition to having high degree aspirations, a large proportion of students attended the college for occupational purposes and created intermediate and long-term goals related to their academic aspirations. The findings of the research confirm findings of previous studies on college student degree aspirations, and add to the understanding of variables contribute to students' educational goals. Recommendations for practice and future research are presented.
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Date Issued: 2014
Identifier: CFE0005539, ucf:50327
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005539

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