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- Title
- Super Resolution of Wavelet-Encoded Images and Videos.
- Creator
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Atalay, Vildan, Foroosh, Hassan, Bagci, Ulas, Hughes, Charles, Pensky, Marianna, University of Central Florida
- Abstract / Description
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In this dissertation, we address the multiframe super resolution reconstruction problem for wavelet-encoded images and videos. The goal of multiframe super resolution is to obtain one or more high resolution images by fusing a sequence of degraded or aliased low resolution images of the same scene. Since the low resolution images may be unaligned, a registration step is required before super resolution reconstruction. Therefore, we first explore in-band (i.e. in the wavelet-domain) image...
Show moreIn this dissertation, we address the multiframe super resolution reconstruction problem for wavelet-encoded images and videos. The goal of multiframe super resolution is to obtain one or more high resolution images by fusing a sequence of degraded or aliased low resolution images of the same scene. Since the low resolution images may be unaligned, a registration step is required before super resolution reconstruction. Therefore, we first explore in-band (i.e. in the wavelet-domain) image registration; then, investigate super resolution.Our motivation for analyzing the image registration and super resolution problems in the wavelet domain is the growing trend in wavelet-encoded imaging, and wavelet-encoding for image/video compression. Due to drawbacks of widely used discrete cosine transform in image and video compression, a considerable amount of literature is devoted to wavelet-based methods. However, since wavelets are shift-variant, existing methods cannot utilize wavelet subbands efficiently. In order to overcome this drawback, we establish and explore the direct relationship between the subbands under a translational shift, for image registration and super resolution. We then employ our devised in-band methodology, in a motion compensated video compression framework, to demonstrate the effective usage of wavelet subbands.Super resolution can also be used as a post-processing step in video compression in order to decrease the size of the video files to be compressed, with downsampling added as a pre-processing step. Therefore, we present a video compression scheme that utilizes super resolution to reconstruct the high frequency information lost during downsampling. In addition, super resolution is a crucial post-processing step for satellite imagery, due to the fact that it is hard to update imaging devices after a satellite is launched. Thus, we also demonstrate the usage of our devised methods in enhancing resolution of pansharpened multispectral images.
Show less - Date Issued
- 2017
- Identifier
- CFE0006854, ucf:51744
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006854
- Title
- Assessing Interactions between Estuary Water Quality and Terrestrial Land Cover in Hurricane Events with Multi-sensor Remote Sensing.
- Creator
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Mostafiz, Chandan, Chang, Ni-bin, Wanielista, Martin, Kibler, Kelly, University of Central Florida
- Abstract / Description
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Estuaries are environmentally, ecologically and environmentally important places as they act as a meeting place for land, freshwater and marine ecosystems. They are also called nurseries of the sea as they often provide nesting and feeding habitats for many aquatic plants and animals. These estuaries also withstand the worst of some natural disasters, especially hurricanes. The estuaries as well as the harbored ecosystems undergo significant changes in terms of water quality, vegetation cover...
Show moreEstuaries are environmentally, ecologically and environmentally important places as they act as a meeting place for land, freshwater and marine ecosystems. They are also called nurseries of the sea as they often provide nesting and feeding habitats for many aquatic plants and animals. These estuaries also withstand the worst of some natural disasters, especially hurricanes. The estuaries as well as the harbored ecosystems undergo significant changes in terms of water quality, vegetation cover etc. and these components are interrelated. When hurricane makes landfall it is necessary to assess the damages as quickly as possible as restoration and recovery processes are time-sensitive. However, assessment of physical damages through inspection and survey and assessment of chemical and nutrient component changes by laboratory testing are time-consuming processes. This is where remote sensing comes into play. With the help of remote sensing images and regression analysis, it is possible to reconstruct water quality maps of the estuary affected. The damage sustained by the vegetation cover of the adjacent coastal watershed can be assessed using Normalized Difference Vegetation Index (NDVI) The water quality maps together with NDVI maps help observe a dynamic sea-land interaction due to hurricane landfall. The observation of hurricane impacts on a coastal watershed can be further enhanced by use of tasseled cap transformation (TCT). TCT plots provide information on a host of land cover conditions with respect to soil moisture, canopy and vegetation cover. The before and after TCT plots help assess the damage sustained in a hurricane event and also see the progress of recovery. Finally, the use of synthetic images obtained by use of data fusion will help close the gap of low temporal resolution of Landsat satellite and this will create a more robust monitoring system.
Show less - Date Issued
- 2017
- Identifier
- CFE0006900, ucf:51729
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006900
- Title
- Interdiffusion, Crystallography and Mechanical Properties of Nickel Manganese Gallium Alloys.
- Creator
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Zhou, Le, Sohn, Yongho, Heinrich, Helge, Coffey, Kevin, An, Linan, Orlovskaya, Nina, University of Central Florida
- Abstract / Description
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NiMnGa Heusler alloys, functioning as either ferromagnetic shape memory alloys or mangetocaloric materials, have both practical applications and fundamental research value. The functional properties of NiMnGa alloys are closely related to the martensitic transformation from high temperature austenitic phase to low temperature martensitic phase. Alloys can be used for room temperature or high temperature applications, depending on the martensitic transformation temperature, which is...
Show moreNiMnGa Heusler alloys, functioning as either ferromagnetic shape memory alloys or mangetocaloric materials, have both practical applications and fundamental research value. The functional properties of NiMnGa alloys are closely related to the martensitic transformation from high temperature austenitic phase to low temperature martensitic phase. Alloys can be used for room temperature or high temperature applications, depending on the martensitic transformation temperature, which is compositional sensitive. The microstructure and crystallography of the martensites can be very complex but are crucial to the optimization of the material performance. In this study, for the first time, a combinatorial study by combining solid-to-solid diffusion couples and various characterization techniques was carried out to fundamentally investigate the NiMnGa ternary alloys. Phase equilibria, interdiffusion behavior, microstructural and crystallographic development, and mechanical properties in NiMnGa alloys were systematically examined. Selected diffusion couples between pure Ni, Ni25Mn75 and four ternary off-stoichiometric NiMnGa alloys (i.e., Ni52Mn18Ga30, Ni46Mn30Ga24, Ni52Mn30Ga18, Ni58Mn18Ga24 in atomic percent) were assembled and annealed at 800, 850 and 900 (&)deg;C for 480, 240 and 120 hours, respectively. The microstructure and concentration profiles of the interdiffusion zone were examined by scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Concentration profiles across the interdiffusion zone were further quantified by electron probe micro analysis (EPMA). Detailed microstructure and crystallography of the austenite and martensite were investigated using transmission electron microscopy (TEM). TEM thin foils were prepared by using focused ion beam (FIB) in situ lift out (INLO) technique, which is able to select desired composition from diffusion couples. The mechanical properties, namely reduced elastic modulus and hardness, as a function of composition were assessed via nanoindentation. Solubility values obtained for various phases were mostly consistent with the existing isothermal phase diagrams, but the phase boundary of the ?(Mn) + ? two-phase region was slightly modified. In addition, equilibrium compositions for the ?(Ni) and ?' phases at 900 (&)deg;C were also determined for the respective two-phase regions. Both austenitic and martensitic phases were found at room temperature in each diffusion couple with a clear interphase boundary. The compositions at the interfaces corresponded close to valence electron concentration (e/a) of 7.6, but decreased to lower values when Mn concentration increased to more than 35 at. %. Average effective interdiffusion coefficients for the ? phase over various compositional ranges were determined and reported in the light of temperature-dependence. Ternary interdiffusion coefficients were also determined and examined to assess the ternary diffusional interactions among Ni, Mn and Ga. Ni was observed to interdiffuse the fastest, followed by Mn then Ga. Interdiffusion flux of Ni also has strong influences on the interdiffusion of Mn and Ga with large and negative cross interdiffusion coefficients. The main ternary interdiffusion coefficients exhibited minimum values near 52 at. % Ni concentration. Extensive TEM analyses have been performed for the study of microstructure and crystallography of austenite and martensite from all diffusion couples. Crystallographic variations in martensitic phase, including non-modulated (NM) martensite, modulated (5M or 7M) martensite, were found in the diffusion couples. The 5M and 7M martensites were only found near the interface between austenite and martensite, corresponding to compositions with lower e/a ratio. The NM martensites were found mostly away from the interface region, with high e/a ratios. The tetragonality ratio (c/a) for NM martensite generally increases with e/a ratio, but also depended on the composition. All martensitic microstructure consists of twinned variants with different orientations that were documented using electron diffraction. The twinning relationship along with the c/a ratio was correlated to martensitic transformation temperature. In addition, pre-martensitic state has been clearly observed in the cubic austenitic phase region, with distinctive tweed microstructure originating from the local lattice distortions. Mechanical properties including reduced elastic modulus (Er) and hardness (H) as a function of composition were measured and analyzed by nanoindentation. A decrease of Er and H was observed with Mn or Ni substituting Ga, and Ni substituting Mn for the austenitic phase. However, an opposite trend was found for the martensitic phase. The softening of the elastic constants near the vicinity of martensitic transformation contributed to the sharp decrease in Er and H near the interface region. The measured Er and H had larger scatter for the martensitic phase than those for the austenitic phase. The scatters observed were attributed to the martensitic variants with different orientations. Contribution from the variation in grain orientation or shape memory effect was determined to be small in this investigation.
Show less - Date Issued
- 2016
- Identifier
- CFE0006204, ucf:51108
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006204
- Title
- Community College Faculty with Corporate Leadership Experience and Full Range Leadership Theory.
- Creator
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Hardee, Gloria, Cintron Delgado, Rosa, Owens, J. Thomas, Cox, Thomas, Bowdon, Melody, University of Central Florida
- Abstract / Description
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Community colleges have developed into vital resources for affordable, easy access, high quality education. Community college instructors with previous leader experience possess the credentials needed to teach their curricula and to lead learning experiences in the classroom. Researchers have found that instructors who display transformational leadership qualities can influence student actions, awareness, and learning outcomes. This study was conducted to explore community college faculty who...
Show moreCommunity colleges have developed into vital resources for affordable, easy access, high quality education. Community college instructors with previous leader experience possess the credentials needed to teach their curricula and to lead learning experiences in the classroom. Researchers have found that instructors who display transformational leadership qualities can influence student actions, awareness, and learning outcomes. This study was conducted to explore community college faculty who possess transformational leadership qualities in relation to student extra effort, student perception of instructor effectiveness, and overall satisfaction with the instructor. The conceptual framework is the full range leadership theory which is one of the most broadly used comprehensive leadership theories. The measurement tool used was Avolio and Bass's (2004) Multifactor Leadership Questionnaire (MLQ), which measures nine factors of leadership skills through a quantitative survey. These findings present support for the recognition of the value of transformational leadership in the community college environment. Consistent with the findings of this study, transformational leadership has been viewed as the most revered leadership model in the full range leadership theory. Instructors have the ability to integrate critical components of transformational leadership behaviors to impact the student experience in the classroom, resulting in higher levels of student outcomes of extra effort, effectiveness, and satisfaction. The findings add to the body of literature and provide insight into the leadership skills of community college instructors from previous business experience.
Show less - Date Issued
- 2014
- Identifier
- CFE0005502, ucf:50351
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005502
- Title
- INVESTIGATION OF THERMAL, ELASTIC AND LOAD-BIASED TRANSFORMATION STRAINS IN NITI SHAPE MEMORY ALLOYS.
- Creator
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Qiu, Shipeng, Vaidyanathan, Raj, University of Central Florida
- Abstract / Description
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Polycrystalline NiTi shape memory alloys have the ability to recover their original, pre-deformed shape in the presence of external loads when heated through a solid-solid phase transformation from a lower-symmetry B19' martensite phase to a higher-symmetry B2 austenite phase. The strain associated with a shape memory alloy in an actuator application typically has thermal, elastic and inelastic contributions. The objective of this work was to investigate the aforementioned strains by...
Show morePolycrystalline NiTi shape memory alloys have the ability to recover their original, pre-deformed shape in the presence of external loads when heated through a solid-solid phase transformation from a lower-symmetry B19' martensite phase to a higher-symmetry B2 austenite phase. The strain associated with a shape memory alloy in an actuator application typically has thermal, elastic and inelastic contributions. The objective of this work was to investigate the aforementioned strains by recourse to in situ neutron diffraction experiments during selected combinations of heating, cooling and/or mechanical loading. The primary studies were conducted on polycrystalline Ni49.9Ti50.1 specimens on the Spectrometer for MAterials Research at Temperature and Stress (SMARTS) at Los Alamos National Laboratory. Quantitative information on the phase-specific strain, texture and phase fraction evolution was obtained from the neutron data using Rietveld refinement and single-peak analyses, and compared with macroscopic data from extensometry. First, the lattice strain evolution during heating and cooling in an unloaded sample (i.e., free-recovery experiment) was studied. The lattice strain evolution remained linear with temperature and was not influenced by intergranular stresses, enabling the determination of a thermal expansion tensor that quantified the associated anisotropy due to the symmetry of B19' NiTi. The tensor thus determined was subsequently used to obtain an average coefficient of thermal expansion that was consistent with macroscopic dilatometric measurements and a 30,000 grain polycrystalline self-consistent model. The accommodative nature of B19' NiTi was found to account for macroscopic shape changes lagging (with temperature) the start and finish of the transformation. Second, the elastic response of B19' martensitic NiTi variants during monotonic loading was studied. Emphasis was placed on capturing and quantifying the strain anisotropy which arises from the symmetry of monoclinic martensite and internal stresses resulting from intergranular constraints between individual variants and load re-distribution among variants as the texture evolved during variant reorientation and detwinning. The methodology adopted took into account both tensile and compressive loading given the asymmetric response in the texture evolution. Plane specific elastic moduli were determined from neutron measurements and compared with those determined using a self-consistent polycrystalline deformation model and from recently reported elastic stiffness constants determined via ab initio calculations. The comparison among the three approaches further helped understand the influence of elastic anisotropy, intergranular constraint, and texture evolution on the deformation behavior of polycrystalline B19' NiTi. Connections were additionally made between the assessed elastic properties of martensitic NiTi single crystals (i.e., the single crystal stiffness tensor) and the overall macroscopic response in bulk polycrystalline form. Lastly, the role of upper-cycle temperature, i.e., the maximum temperature reached during thermal cycling, was investigated during load-biased thermal cycling of NiTi shape memory alloys at selected combinations of stress and temperature. Results showed that the upper-cycle temperature, under isobaric conditions, significantly affected the amount of transformation strain and thus the work output available for actuation. With the objective of investigating the underlying microstructural and micromechanical changes due to the influence of the upper-cycle temperature, the texture evolution was systematically analyzed. While the changes in transformation strain were closely related to the evolution in texture of the room temperature martensite, retained martensite in the austenite state could additionally affect the transformation strain. Additionally, multiple thermal cycles were performed under load-biased conditions in both NiTi and NiTiPd alloys, to further assess and understand the role of retained martensite. Dimensional and thermal stabilities of these alloys were correlated with the volume fraction and texture of retained martensite, and the internal strain evolution in these alloys. The role of symmetry, i.e., B19' monoclinic martensite vs. B19 orthorhombic martensite in these alloys was also assessed. This work not only established a methodology to study the thermal and elastic properties of the low symmetry B19' monoclinic martensite, but also provided valuable insight into quantitative micromechanical and microstructural changes responsible for the thermomechanical response of NiTi shape memory alloys. It has immediate implications for optimizing shape memory behavior in the alloys investigated, with extension to high temperature shape memory alloys with ternary and quaternary elemental additions, such as Pd, Pt and Hf. This work was supported by funding from NASAÂÂ's Fundamental Aeronautics Program, Supersonics Project (NNX08AB51A) and NSF (CAREER DMR-0239512). It benefited additionally from the use of the Lujan Neutron Scattering Center at Los Alamos National Laboratory, which is funded by the Office of Basic Energy Sciences (Department of Energy) and is operated by Los Alamos National Security LLC under DOE Contract DE-AC52-06NA25396.
Show less - Date Issued
- 2010
- Identifier
- CFE0003362, ucf:48440
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003362
- Title
- A NON-ISOLATED HALF BRIDGE BUCK-BASED CONVERTER FOR VRM APPLICATION AND SMALL SIGNAL MODELING OF A NON-CONVENTIONAL TWO PHASE BUCK.
- Creator
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Batarseh, Majd, Batarseh, Issa, University of Central Florida
- Abstract / Description
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The challenges imposed on Voltage Regulator Modules (VRM) become difficult to be achieved with the conventional multiphase buck converter commonly used on PC motherboards. For faster data transfer, a decrease in the output voltage is needed. This decrease causes small duty cycle that is accompanied by critical problems which impairs the efficiency. Therefore, these problems need to be addressed. Transformer-based non-isolated topologies are not new approaches to extend the duty cycle and...
Show moreThe challenges imposed on Voltage Regulator Modules (VRM) become difficult to be achieved with the conventional multiphase buck converter commonly used on PC motherboards. For faster data transfer, a decrease in the output voltage is needed. This decrease causes small duty cycle that is accompanied by critical problems which impairs the efficiency. Therefore, these problems need to be addressed. Transformer-based non-isolated topologies are not new approaches to extend the duty cycle and avoid the associated drawbacks. High leakage, several added components and complicated driving and control schemes are some of the trade-offs to expand the duty cycle. The objective of this work is to present a new dc-dc buck-based topology, which extends the duty cycle with minimum drawbacks by adding two transformers that can be integrated to decrease the size and two switches with zero voltage switching (ZVS). Another issue addressed in this thesis is deriving a small signal model for a two-input two-phase buck converter as an introduction to a new evolving field of multi-input converters.
Show less - Date Issued
- 2006
- Identifier
- CFE0001513, ucf:47130
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001513
- Title
- MECHANISMS OF LIFETIME IMPROVEMENT IN THERMAL BARRIER COATINGS WITH HF AND/OR Y MODIFICATION OF CMSX-4 SUPERALLOY SUBSTRATES.
- Creator
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Liu, Jing, Sohn, Yong ho, University of Central Florida
- Abstract / Description
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In modern turbine engines for propulsion and energy generation, thermal barrier coating (TBCs) protect hot-section blades and vanes, and play a critical role in enhancing reliability, durability and operation efficiency. In this study, thermal cyclic lifetime and microstructural degradation of electron beam physical vapor deposited (EB-PVD) Yttria Stabilized Zirconia (YSZ) with (Ni,Pt)Al bond coat and Hf- and/or Y- modified CMSX-4 superalloy substrates were examined. Thermal cyclic lifetime...
Show moreIn modern turbine engines for propulsion and energy generation, thermal barrier coating (TBCs) protect hot-section blades and vanes, and play a critical role in enhancing reliability, durability and operation efficiency. In this study, thermal cyclic lifetime and microstructural degradation of electron beam physical vapor deposited (EB-PVD) Yttria Stabilized Zirconia (YSZ) with (Ni,Pt)Al bond coat and Hf- and/or Y- modified CMSX-4 superalloy substrates were examined. Thermal cyclic lifetime of TBCs was measured using a furnace thermal cycle test that consisted of 10-minute heat-up, 50-minute dwell at 1135C, and 10-minute forced-air-quench. TBC lifetime was observed to improve from 600 cycles to over 3200 cycles with appropriated Hf- and/or Y alloying of CMSX-4 superalloys. This significant improvement in TBC lifetime is the highest reported lifetime in literature with similar testing parameters. Beneficial role of reactive element (RE) on the durability of TBCS were systematically investigated in this study. Photostimulated luminescence spectroscopy (PL) was employed to non-destructively measure the residual stress within the TGO scale as a function of thermal cycling. Extensive microstructural analysis with emphasis on the YSZ/TGO interface, TGO scale, TGO/bond coat interface was carried out by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and scanning electron microscopy (STEM) as a funcion of thermal cycling including after the spallation failure. Focused ion beam in-situ lift-out (FIB-INLO) technique was employed to prepare site-specific TEM specimens. X-ray diffraction (XRD) and secondary ion mass spectroscopy (SIMS) were also employed for phase identification and interfacial chemical analysis. While undulation of TGO/bond coat interface (e.g., rumpling and ratcheting) was observed to be the main mechanism of degradation for the TBCs on baseline CMSX-4, the same interface remained relatively flat (e.g., suppressed rumpling and ratcheting) for durable TBCs on Hf- and/or Y-modified CMSX-4. The fracture paths changed from the YSZ/TGO interface to the TGO/bond coat interface when rumpling was suppressed. The geometrical incompatibility between the undulated TGO and EB-PVD YSZ lead to the failure at the YSZ/TGO interface for TBCs with baseline CMSX-4. The magnitude of copressive residual stress within the TGO scale measured by PL gradually decreased as a function of thermal cycling for TBCs with baseline CMSX-4 superalloy substrates. This gradual decrease corrsponds well to the undulation of the TGO scale that may lead to relaxation of the compressive residual stress within the TGO scale. For TBCs with Hf- and/or Y-modified CMSX-4 superalloy substrates, the magnitude of compressive residual stress within the TGO scale remained relatively constant throughout the thermal cycling, although PL corresponding to the stress-relief caused by localized cracks at the TGO/bond coat interface and within the TGO scale was observed frequently starting 50% of lifetime. A slightly smaller parabolic growth constant and grain size of the TGO scale was observed for TBCs with Hf- and/or Y- modified CMSX-4. Small monoclinic HfO2 precipitates were observed to decorate grain boundaries and the triple pointes within the alpha-Al2O3 scale for TBCs with Hf- and/or Y-modified CMSX-4 substrates. Segregation of Hf/Hf4+ at the TGO/bond coat interfaces was also observed for TBCs with Hf- and/or Y-modified CMSX-4 superalloys substrates. Adherent and pore-free YSZ/TGO interface was observed for TBCs with Hf- and/or Y-modified CMSX-4, while a significant amount of decohesion at the YSZ/TGO interface was observed for TBCs with baseline CMSX-4. The beta-NiAl(B2) phase in the (Ni,Pt)Al bond coat was observed to partially transform into gama prime-Ni3Al (L12) phase due to depletion of Al in the bond coat during oxidation. More importantly, the remaining beta-NiAl phase transformed into L10 martensitic phase upon cooling even though there was no significant difference in these phase transformations for all TBCs. Results from these microstructural observations are documented to elucidate mechanisms that suppress the rumpling of the TGO/bond coat interface, which is responsible for superior performance of EB-PVD TBCs with (Ni,Pt)Al bond coat and Hf- and/or Y-modified CMXS-4 superalloy.
Show less - Date Issued
- 2007
- Identifier
- CFE0001872, ucf:47382
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001872
- Title
- EXPRESSION OF CHOLERA TOXIN B SUBUNIT-ROTAVIRUS NSP4 ENTEROTOXIN FUSION PROTEIN IN TRANSGENIC CHLOROPLASTS.
- Creator
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Kalluri, Anila, Daniell, Henry, University of Central Florida
- Abstract / Description
-
Rotavirus, the major cause of life-threatening infantile gastroenteritis, is a member of the Reoviridae family and is considered to be the single most important cause of virus-based severe diarrheal illness in infants and young children particularly 6 months to 2 years of age in industrialized and developing countries. Infection in infants and young children is often accompanied by severe life threatening diarrhea, most commonly following primary infection. Diarrhea is the major cause of...
Show moreRotavirus, the major cause of life-threatening infantile gastroenteritis, is a member of the Reoviridae family and is considered to be the single most important cause of virus-based severe diarrheal illness in infants and young children particularly 6 months to 2 years of age in industrialized and developing countries. Infection in infants and young children is often accompanied by severe life threatening diarrhea, most commonly following primary infection. Diarrhea is the major cause of death among children around the world. Responsible for 4 to 6 million deaths per year according to the World Health Organization (WHO), diarrhea is especially dangerous for infants and young children. Globally, it is estimated that 1.4 billion episodes of diarrhea occur in children less than five years of age annually. In the United States alone, rotavirus causes more than 3 million cases of childhood diarrhea each year, leading to an estimated 55,000 to 100,000 hospitalizations and 20 to 100 deaths. And is a major cause of mortality for children in developing countries with approximately one million deaths annually. Rotaviruses belong to the family Reoviridae and are spherical 70-nm particles. The virus genome contains 11 segments of double-stranded RNA, each encoding a viral capsid or nonstructural protein. The identification of a rotavirus nonstructural protein gene (NSP4) encoding a peptide, which functions both as a viral enterotoxin and as a factor involved in the acquisition of host cell membrane during virus budding from cells, provides a new approach for mucosal immunization. Protein expression through chloroplast transformation system offers a number of advantages like high level of transgene expression, transgene containment via maternal inheritance, lack of gene silencing and position effect due to site specific gene integration and also the possibility of multi gene engineering in single transformation event. It is also an environmentally friendly approach due to effective gene containment and lack of transgene expression in pollen. To achieve an enhanced immune response to rotavirus infection, a fusion gene encoding the cholera toxin B subunit linked to rotavirus enterotoxin 90 aa protein (CTB-NSP490) was introduced into transgenic chloroplast and was transformed into chloroplast genome of Nicotiana tabacum by homologous recombination. The chloroplast integration of CTB-NSP4(90) fusion gene was confirmed in transgenic tobacco plants by PCR analysis. Southern blot analysis further confirmed site specific gene integration and homoplasmy. Immunoblot analysis of transformed chloroplast confirmed the expression of CTBNSP490 fusion protein both in monomeric and pentameric forms that retained the binding affinity to the enterocytes GM1 ganglioside receptor. Expression levels of CTB-NSP4 protein was quantified by GM1 ganglioside binding ELISA assay; mature leaves expressed CTB-NSP4 fusion protein to upto 2.45 % in total soluble protein, 100-400 fold higher than nuclear expression which was only 0.006%-0.026%. Antibody titration and virus challenge experiments will be performed in mice at Loma Linda University to evaluate the antigenic and protective properties of the chloroplast derived CTB-NSP4 fusion protein.
Show less - Date Issued
- 2005
- Identifier
- CFE0000655, ucf:46540
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000655
- Title
- STRUCTURAL TRANSITION DURING FIBRILLOGENESIS OF AMYLOID ? PEPTIDE.
- Creator
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Sidrak, George, Tatulian, Suren, University of Central Florida
- Abstract / Description
-
Alzheimer's Disease (AD) is a neurodegenerative disease marked by progressive neuronal cell death, leading to dementia. AD is the most common disease that results in dementia and largely affects the elderly, with five million people in the United States diagnosed with the disease as of 2015 and approximately 35 million people worldwide. Diseases resulting in dementia cost the US healthcare system an estimated $172 billion in 2010 and that cost is expected to increase as the population ages...
Show moreAlzheimer's Disease (AD) is a neurodegenerative disease marked by progressive neuronal cell death, leading to dementia. AD is the most common disease that results in dementia and largely affects the elderly, with five million people in the United States diagnosed with the disease as of 2015 and approximately 35 million people worldwide. Diseases resulting in dementia cost the US healthcare system an estimated $172 billion in 2010 and that cost is expected to increase as the population ages and as diagnostic techniques improve so that more people are treated (Holtzman, 2011). The disease was first reported by psychiatrist Alois Alzheimer at the onset of the 20th century, when one of his patients "suffered memory loss, disorientation, hallucinations and delusions and died at the age of 55," then was found to have severe brain atrophy post-mortem (Cipriani, Dolciotti, Picchi, & Bonuccelli, 2011). There are palliative treatments available that marginally slow disease progression but there is currently no cure for the disease (Awasthi, Singh, Pandey, & Dwivedi, 2016). More research is needed to develop effective therapeutic strategies to combat the disease. Currently, AD cytotoxicity is believed to be caused by increased amyloid ? (A?) peptide plaque deposition in the brain, as described by the amyloid cascade hypothesis (Barage & Sonawane, 2015). The current understanding is that oligomers of A? peptide lead to neuronal death through multiple mechanisms, most notably hyper-phosphorylation of the tau protein. Having a better understanding of the structural changes in the fibrillization process of A? will provide a broader insight into mechanisms of cell death and open new possibilities for pharmacological treatments, which is what this research intends to provide.
Show less - Date Issued
- 2017
- Identifier
- CFH2000178, ucf:45994
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000178
- Title
- EMBEDDED MAGNETICS FOR POWER SYSTEM ON CHIP (PSOC).
- Creator
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Lu, Jian, Shen, Z. John, University of Central Florida
- Abstract / Description
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A novel concept of on-chip bondwire inductors and transformers with ferrite epoxy glob coating is proposed, offering a cost effective approach to realize power systems on chip (PSoC) or System-in-Package (PSiP). The concept has been investigated both experimentally and with finite element modeling. Improvement in total inductance is demonstrated for multi-turn bondwire inductors over single bondwire inductors. The inductance and Q factor can be further boosted with coupled multi-turn inductor...
Show moreA novel concept of on-chip bondwire inductors and transformers with ferrite epoxy glob coating is proposed, offering a cost effective approach to realize power systems on chip (PSoC) or System-in-Package (PSiP). The concept has been investigated both experimentally and with finite element modeling. Improvement in total inductance is demonstrated for multi-turn bondwire inductors over single bondwire inductors. The inductance and Q factor can be further boosted with coupled multi-turn inductor concept. Transformer parameters including self- and mutual inductance, and coupling factors are extracted from both modeled and measured S-parameters. More importantly, the bondwire magnetic components can be easily integrated into SoC manufacturing processes with minimal changes to the layout, and open enormous possibilities for realizing cost-effective, high current, high efficiency PSoC's or PSiP's. The design guidelines for single bondwire inductors as well as multi-turn inductors are discussed step by step in several chapters. Not only is the innovated concept for bondwire inductor with ferrite ink presented, but also the practical implementation and design rules are given. With all the well defined steps, people who want to use these bondwire inductors with ferrite ink in their PSoC research or products will find it as simple as using commercial inductors. Last but not least, the PSoC concept using a bondwire inductor is demonstrated by building the prototype of dc-dc buck converter IC as well as the whole package. IC and the whole function block are tested and presented in this work.
Show less - Date Issued
- 2009
- Identifier
- CFE0002952, ucf:47953
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002952
- Title
- PHASE-SHIFTING HAAR WAVELETS FOR IMAGE-BASED RENDERING APPLICATIONS.
- Creator
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Alnasser, Mais, Foroosh, Hassan, University of Central Florida
- Abstract / Description
-
In this thesis, we establish the underlying research background necessary for tackling the problem of phase-shifting in the wavelet transform domain. Solving this problem is the key to reducing the redundancy and huge storage requirement in Image-Based Rendering (IBR) applications, which utilize wavelets. Image-based methods for rendering of dynamic glossy objects do not truly scale to all possible frequencies and high sampling rates without trading storage, glossiness, or computational time,...
Show moreIn this thesis, we establish the underlying research background necessary for tackling the problem of phase-shifting in the wavelet transform domain. Solving this problem is the key to reducing the redundancy and huge storage requirement in Image-Based Rendering (IBR) applications, which utilize wavelets. Image-based methods for rendering of dynamic glossy objects do not truly scale to all possible frequencies and high sampling rates without trading storage, glossiness, or computational time, while varying both lighting and viewpoint. This is due to the fact that current approaches are limited to precomputed radiance transfer (PRT), which is prohibitively expensive in terms of memory requirements when both lighting and viewpoint variation are required together with high sampling rates for high frequency lighting of glossy material. At the root of the above problem is the lack of a closed-form run-time solution to the nontrivial problem of rotating wavelets, which we solve in this thesis. We specifically target Haar wavelets, which provide the most efficient solution to solving the tripleproduct integral, which in turn is fundamental to solving the environment lighting problem. The problem is divided into three main steps, each of which provides several key theoretical contributions. First, we derive closed-form expressions for linear phase-shifting in the Haar domain for one-dimensional signals, which can be generalized to N-dimensional signals due to separability. Second, we derive closed-form expressions for linear phase-shifting for two-dimensional signals that are projected using the non-separable Haar transform. For both cases, we show that the coefficients of the shifted data can be computed solely by using the coefficients of the original data. We also derive closed-form expressions for non-integer shifts, which has not been reported before. As an application example of these results, we apply the new formulae to image shifting, rotation and interpolation, and demonstrate the superiority of the proposed solutions to existing methods. In the third step, we establish a solution for non-linear phase-shifting of two-dimensional non-separable Haar-transformed signals, which is directly applicable to the original problem of image-based rendering. Our solution is the first attempt to provide an analytic solution to the difficult problem of rotating wavelets in the transform domain.
Show less - Date Issued
- 2008
- Identifier
- CFE0002214, ucf:47882
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002214
- Title
- Effects of Allotropic Transformations on Interdiffusion Behavior in Binary Systems.
- Creator
-
Ewh, Ashley, Sohn, Yongho, Suryanarayana, Challapalli, Coffey, Kevin, University of Central Florida
- Abstract / Description
-
Diffusion plays a significant role in most materials systems by controlling microstructural development. Consequently, the overall properties of a material can be largely dependent upon diffusion. This study investigated the interdiffusion behavior of three binary systems, namely, Mo-Zr, Fe-Mo, and Fe-Zr. The main interest in these particular metals is for application in nuclear fuel assemblies. Nuclear fuel plates generally consist of two main components which are the fuel and the cladding....
Show moreDiffusion plays a significant role in most materials systems by controlling microstructural development. Consequently, the overall properties of a material can be largely dependent upon diffusion. This study investigated the interdiffusion behavior of three binary systems, namely, Mo-Zr, Fe-Mo, and Fe-Zr. The main interest in these particular metals is for application in nuclear fuel assemblies. Nuclear fuel plates generally consist of two main components which are the fuel and the cladding. Due to diffusional interactions that can occur between these two components, a third is sometimes added between the fuel and cladding to serve as a diffusion barrier layer. Fe, Mo, and Zr can act as either cladding or barrier layer constituents and both Mo and Zr also serve as alloying additions in uranium based metallic fuels. Therefore, a fundamental understanding of the diffusional interactions in these systems is critical in predicting the performance and lifetime of these fuels. In order to study this diffusion behavior, a series of solid-to-solid diffusion couples were assembled between Fe, Mo, and Zr. These couples were then diffusion annealed isothermally for various predetermined times over a range of temperatures, including some both above and below the allotropic transformation temperatures for Fe and Zr. Following the diffusion anneal, the couples were water quenched, cross-sectioned, and prepared for microstructural and compositional characterization. A combination of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and electron probe microanalysis (EPMA) were used to obtain micrographs showing the microstructure and to collect compositional data for identifying intermediate phases and determining concentration profiles across the interdiffusion zone.Based on this characterization, the phases that developed in the diffusion zones were identified. In the Mo-Zr system, a large Zr solid solution layer developed in the couples annealed at and above 850(&)deg;C and a thin (~1-2 ?m) layer of Mo2Zr formed in all couples. Growth constants and concentration dependent interdiffusion coefficients were calculated for the Mo2Zr and Zr solid solution phases, respectively. In the Fe-Mo system, both the ?-Fe2Mo and ?-Fe7Mo6 phases were observed in couples annealed at 900(&)deg;C and below while ?-Fe7Mo6 and ?-Fe solid solution layers were observed in couples annealed above 900(&)deg;C. The relevant growth constants and activation energies for growth were calculated. In the Fe-Zr system, the couple annealed at 750(&)deg;C developed an FeZr2 and an FeZr3 layer while the couple annealed at 850(&)deg;C developed an Fe2Zr and Fe23Zr6 layer in the diffusion zone. The results of this analysis were then compared to available information from literature and the corresponding binary phase diagrams for each system. The results are discussed with respect to the effects of the allotropic transformations of Fe and Zr on the interdiffusion behavior in these systems.
Show less - Date Issued
- 2012
- Identifier
- CFE0004374, ucf:49422
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004374
- Title
- DETERMINANTS OF CHLOROPLAST GENE EXPRESSION AND APPLICATIONS OF CHLOROPLAST TRANSFORMATION IN LACTUCA SATIVA AND NICOTIANA TABACUM.
- Creator
-
Ruhlman, Tracey, Daniell, Henry, University of Central Florida
- Abstract / Description
-
Genetic modification of plastids in the model plant tobacco (Nicotiana tabacum) has demonstrated that numerous foreign gene products can accumulate to high levels in this setting. Plastid biotechnology is maturing to encompass the improvement of food and feed species and the production of biopharmaceutical proteins for oral delivery necessitating development of stable transplastomic edible plants. In the interest of establishing an edible platform we have investigated the use of native and...
Show moreGenetic modification of plastids in the model plant tobacco (Nicotiana tabacum) has demonstrated that numerous foreign gene products can accumulate to high levels in this setting. Plastid biotechnology is maturing to encompass the improvement of food and feed species and the production of biopharmaceutical proteins for oral delivery necessitating development of stable transplastomic edible plants. In the interest of establishing an edible platform we have investigated the use of native and foreign regulatory elements in relation to foreign gene expression in plastids. Multiple sequence alignments of intergenic regions for 20 species of angiosperm showed that despite 95% identity in the coding region, identity in the psbA upstream region is 59% across all taxa examined, other gene coding regions displayed sequence identity of 80-97%, whereas the non-coding regions were 45-79% suggesting that our physical data can be extrapolated beyond the model presented. We found that by exchanging psbA untranslated regions (UTRs) between N. tabacum and lettuce (Lactuca sativa), the expression of the CTB-proinsulin (CTB-Pins) monocistronic transcript declined by 84% and foreign protein accumulation was reduced by as much as 97% in mature leaves. Polyribosome association assays suggest that ribosome-free transgenic transcripts are stabilized where the native UTR is employed. RNA EMSA revealed that binding proteins interacted with psbA 5' UTRs in a species specific manner and the half life of the L. sativa 5'UTR-CTB-Pins mRNA was reduced by 3.7 fold in N. tabacum stromal extracts. Our data indicate that the use of species-specific regulatory elements could lead to establishment of reproducible plastid transformation in desirable target species such as L. sativa. Using transplastomic L. sativa for oral delivery of bioencapsulated CTB-Pins we delayed the onset of diabetes in NOD mice when retinyl acetate supplement was provided compared to untouched mice. In this 30 week study we monitored blood glucose levels and evaluated the in vitro suppressive capacity of regulatory T cells isolated from diabetic mice. Whether delay or prevention was achieved appeared to be a function of antigen dose as high dose resulted in a nine week delay of onset while low dose reduced the incidence of diabetes by 36%. In addition we have evaluated metabolic engineering in the N. tabacum model where we generated cis-genic lines expressing nucleus-encoded methionine pathway enzymes in plastids. Transplastomic expression of Cystathionine gamma-Synthase led to a three-fold increase in enzyme activity and a doubling of methionine content in leaves without a deleterious phenotype. In exploring molecular mechanisms supporting gene expression in plastids and applying transplastomic technology to real human problems this work seeks address the potential of plastid biotechnology for improvement of commodity crops and production of biopharmaceuticals.
Show less - Date Issued
- 2009
- Identifier
- CFE0002687, ucf:48236
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002687
- Title
- Phase Transformations and Microstructural Evolution in the U-10 wt.% Mo Alloy with Various Zr Additions at 900C and 650C.
- Creator
-
Eriksson, Nicholas, Sohn, Yongho, Challapalli, Suryanarayana, Coffey, Kevin, University of Central Florida
- Abstract / Description
-
The Reduced Enrichment for Research and Test Reactor (RERTR) now known as the Material Minimization and Management Reactor Control program (MMMRC) seeks to replace the use of highly enriched uranium (HEU) fuels used in research and test nuclear reactors around the world. The low enriched uranium (LEU) fuels must have fissionable uranium densities comparable to the HEU fuels. After extensive investigation by various researchers around the world, the U-Mo alloys were selected as a promising...
Show moreThe Reduced Enrichment for Research and Test Reactor (RERTR) now known as the Material Minimization and Management Reactor Control program (MMMRC) seeks to replace the use of highly enriched uranium (HEU) fuels used in research and test nuclear reactors around the world. The low enriched uranium (LEU) fuels must have fissionable uranium densities comparable to the HEU fuels. After extensive investigation by various researchers around the world, the U-Mo alloys were selected as a promising candidate. The Mo alloyed with U allows for the stabilization of the face-centered cubic ?-U phase, which demonstrated favorable irradiation behavior. However, deleterious diffusional interaction between the fuel and the cladding, typically Al-base alloy, remain a challenge to overcome for application of U-Mo alloys as the LEU fuel. Zr has been identified as a potential diffusion barrier between monolithic U-10 wt.% Mo (U10Mo) metallic fuel and AA6061 cladding alloys for the development of a LEU fuel system. However, interdiffusion and reaction between the Zr barrier and U10Mo fuel can produce phases such as Mo2Zr, and promote the destabilization of ?-U phase into ?'-U (U2Mo) and ?-U. In order to better understand this phenomenon, this study examined the phases that are present in the U10Mo alloys with varying Zr concentration, 0, 0.5, 1.0, 2.0, 5.0, 10.0, 20.0 wt.% at room temperature after heat treatment at 900(&)deg;C for 168 hours and 650(&)deg;C for 3 hours. These two temperatures are relevant to fuel plate fabrication process of homogenization and hot-rolling, respectively. Scanning electron microscopy and X-ray diffraction were employed to identify and quantitatively document the constituent phases and microstructure to elucidate the nature of phase transformations. For U10Mo alloys containing less than 1.0 wt.% Zr, there was no significant formation of Mo2Zr after 900?C homogenization and subsequent heat treatment at 650?C for 3 hours. The ?-U phase also remained stable correspondingly for these alloys containing less than 1.0 wt.% Zr. For U10Mo alloys containing 2 wt.% or more Zr, a significant amount of Mo2Zr formation was observed after 900?C homogenization and subsequent heat treatment at 650?C for 3 hours. For these alloys, destabilization of ?-U into ?'-U (U2Mo), UZr2 and ?-U was observed. The alloy containing 20 wt.% Zr, however, did not demonstrate ?-U decomposition even though Mo2Zr was observed after heat treatments. The formation of Mo2Zr effectively reduced the stability of the metastable ?-U phase by depleting the ?-stabilizing Mo. The destabilization of ?-U phase into the ?-U phase is not favorable due to anisotropic and poor irradiation behavior of ?-U phase. Therefore the formation of Mo2Zr at the interface between U10Mo fuel and Zr diffusion barrier must be carefully controlled during the fabrication of monolithic LEU fuel system for successful implementation.
Show less - Date Issued
- 2015
- Identifier
- CFE0005943, ucf:50812
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005943
- Title
- Signal processing with Fourier analysis, novel algorithms and applications.
- Creator
-
Syed, Alam, Foroosh, Hassan, Sun, Qiyu, Bagci, Ulas, Rahnavard, Nazanin, Atia, George, Katsevich, Alexander, University of Central Florida
- Abstract / Description
-
Fourier analysis is the study of the way general functions may be represented or approximatedby sums of simpler trigonometric functions, also analogously known as sinusoidal modeling. Theoriginal idea of Fourier had a profound impact on mathematical analysis, physics, and engineeringbecause it diagonalizes time-invariant convolution operators. In the past signal processing was atopic that stayed almost exclusively in electrical engineering, where only the experts could cancelnoise, compress...
Show moreFourier analysis is the study of the way general functions may be represented or approximatedby sums of simpler trigonometric functions, also analogously known as sinusoidal modeling. Theoriginal idea of Fourier had a profound impact on mathematical analysis, physics, and engineeringbecause it diagonalizes time-invariant convolution operators. In the past signal processing was atopic that stayed almost exclusively in electrical engineering, where only the experts could cancelnoise, compress and reconstruct signals. Nowadays it is almost ubiquitous, as everyone now dealswith modern digital signals.Medical imaging, wireless communications and power systems of the future will experience moredata processing conditions and wider range of applications requirements than the systems of today.Such systems will require more powerful, efficient and flexible signal processing algorithms thatare well designed to handle such needs. No matter how advanced our hardware technology becomeswe will still need intelligent and efficient algorithms to address the growing demands in signalprocessing. In this thesis, we investigate novel techniques to solve a suite of four fundamentalproblems in signal processing that have a wide range of applications. The relevant equations, literatureof signal processing applications, analysis and final numerical algorithms/methods to solvethem using Fourier analysis are discussed for different applications in the electrical engineering /computer science. The first four chapters cover the following topics of central importance in thefield of signal processing: Fast Phasor Estimation using Adaptive Signal Processing (Chapter 2) Frequency Estimation from Nonuniform Samples (Chapter 3) 2D Polar and 3D Spherical Polar Nonuniform Discrete Fourier Transform (Chapter 4)iv Robust 3D registration using Spherical Polar Discrete Fourier Transform and Spherical Harmonics(Chapter 5)Even though each of these four methods discussed may seem completely disparate, the underlyingmotivation for more efficient processing by exploiting the Fourier domain signal structureremains the same. The main contribution of this thesis is the innovation in the analysis, synthesis, discretization of certain well-known problems like phasor estimation, frequency estimation, computations of a particular non-uniform Fourier transform and signal registration on the transformed domain. We conduct propositions and evaluations of certain applications relevant algorithms suchas, frequency estimation algorithm using non-uniform sampling, polar and spherical polar Fourier transform. The techniques proposed are also useful in the field of computer vision and medical imaging. From a practical perspective, the proposed algorithms are shown to improve the existing solutions in the respective fields where they are applied/evaluated. The formulation and final proposition is shown to have a variety of benefits. Future work with potentials in medical imaging, directional wavelets, volume rendering, video/3D object classifications, high dimensional registration are also discussed in the final chapter. Finally, in the spirit of reproducible research, we release the implementation of these algorithms to the public using Github.
Show less - Date Issued
- 2017
- Identifier
- CFE0006803, ucf:51775
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006803
- Title
- Scientific transformations: a philosophical and historical analysis of cosmology from Copernicus to Newton.
- Creator
-
Castillo, Manuel-Albert, Jones, Donald, Dandrow, Edward, Garbayo, Luciana, University of Central Florida
- Abstract / Description
-
The purpose of this thesis is to show a transformation around the scientific revolution from the sixteenth to seventeenth centuries against a Whig approach in which it still lingers in the history of science. I find the transformations of modern science through the cosmological models of Nicholas Copernicus, Johannes Kepler, Galileo Galilei and Isaac Newton. Since of the enormous content, I shall only pay particular attention to Copernicus and Newton in which the emerging sciences transformed...
Show moreThe purpose of this thesis is to show a transformation around the scientific revolution from the sixteenth to seventeenth centuries against a Whig approach in which it still lingers in the history of science. I find the transformations of modern science through the cosmological models of Nicholas Copernicus, Johannes Kepler, Galileo Galilei and Isaac Newton. Since of the enormous content, I shall only pay particular attention to Copernicus and Newton in which the emerging sciences transformed the cosmos on what Alexandre Koyr(&)#233; calls from a (")closed world to infinite universe(").As an interdisciplinary approach, I used the methods and inquiries from philosophy and history to explain the cosmological transformation in the sciences. The first part deals on the philosophic content of Michel Foucault and Thomas Kuhn which help to provide insight though their systematic thoughts are incompatible. The second part deals in the historic contents from Copernicus' doctrine, De revolutionibus, to Newton's mechanics, Principia. My ultimate outcome is to demonstrate the multi-perspective dimension of knowledge in which interdisciplinary studies shows transformation of the sciences and its effects on history
Show less - Date Issued
- 2017
- Identifier
- CFE0006862, ucf:51738
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006862
- Title
- "The Best Thing Sociology Can Do": The Transformative Potential of a Community Action and Involvement Course.
- Creator
-
Savage, Brenda, Mustaine, Elizabeth, Grauerholz, Liz, Carter, Shannon, Sweet, Stephen, University of Central Florida
- Abstract / Description
-
This research explores the transformative potential of a Community Action and Involvement course, an undergraduate sociological elective taught at a large southeastern university, to develop or support undergraduates' sense of personal agency and provide the resources necessary for them to engage in the work of social change. The research is rooted in both Bourdieu's conceptualization of habitus and the work of Carmen Mills (2008) on the simultaneous existence of a reproductive and...
Show moreThis research explores the transformative potential of a Community Action and Involvement course, an undergraduate sociological elective taught at a large southeastern university, to develop or support undergraduates' sense of personal agency and provide the resources necessary for them to engage in the work of social change. The research is rooted in both Bourdieu's conceptualization of habitus and the work of Carmen Mills (2008) on the simultaneous existence of a reproductive and transformative habitus within students. This is a mixed methods study, which includes the analysis of pre- and post-course survey data and over 800 student writings collected during the course to uncover student attitudes and behaviors regarding social change. Results suggest that many of the 47 students credited the course with their increased optimism and confidence in their own potential to change things in society; additionally, they felt they gained tools they needed to cause social change. Further, in relation to the theorization of the dialectic of the reproductive/transformative habitus, complexities emerged as indicators, including desire, feelings, beliefs, and actions, were uncovered, thus complicating the attempt to understand if the students in the class were exhibiting a reproductive or a transformative habitus. This research, though limited to the outcomes of a single course contributes to the understanding of both the need for and the student response to action-oriented sociology courses; it also suggests pedagogical aspects that students might find helpful in such classes. Finally, this study opens the door for further research into the effect of social location on undergraduates' outlook on society and their ability to cause change, as well as additional testing of the theorization of the reproductive/transformative habitus.
Show less - Date Issued
- 2017
- Identifier
- CFE0006790, ucf:51828
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006790
- Title
- Planning and Control of Swarm Motion as Continua.
- Creator
-
Rastgoftar, Hossein, Jayasuriya, Suhada, Das, Tuhin, Xu, Chengying, Qu, Zhihua, Simaan, Marwan, University of Central Florida
- Abstract / Description
-
In this thesis, new algorithms for formation control of multi agent systems (MAS) based on continuum mechanics principles will be investigated. For this purpose agents of the MAS are treated as particles in a continuum, evolving in an n-D space, whose desired configuration is required to satisfy an admissible deformation function. Considered is a specific class of mappings that is called homogenous where the Jacobian of the mapping is only a function of time and is not spatially varying. The...
Show moreIn this thesis, new algorithms for formation control of multi agent systems (MAS) based on continuum mechanics principles will be investigated. For this purpose agents of the MAS are treated as particles in a continuum, evolving in an n-D space, whose desired configuration is required to satisfy an admissible deformation function. Considered is a specific class of mappings that is called homogenous where the Jacobian of the mapping is only a function of time and is not spatially varying. The primary objectives of this thesis are to develop the necessary theory and its validation via simulation on a mobile-agent based swarm test bed that includes two primary tasks: 1) homogenous transformation of MAS and 2) deployment of a random distribution of agents on to a desired configuration. Developed will be a framework based on homogenous transformations for the evolution of a MAS in an n-D space (n=1, 2, and 3), under two scenarios: 1) no inter-agent communication (predefined motion plan); and 2) local inter-agent communication. Additionally, homogenous transformations based on communication protocols will be used to deploy an arbitrary distribution of a MAS on to a desired curve. Homogenous transformation with no communication: A homogenous transformation of a MAS, evolving in an R^n space, under zero inter agent communication is first considered. Here the homogenous mapping, is characterized by an n x n Jacobian matrix Q(t) and an n x 1 rigid body displacement vector D(t), that are based on positions of n+1 agents of the MAS, called leader agents. The designed Jacobian Q(t) and rigid body displacement vector D(t) are passed onto rest of the agents of the MAS, called followers, who will then use that information to update their positions under a pre-defined motion plan. Consequently, the motion of MAS will evolve as a homogenous transformation of the initial configuration without explicit communication among agents. Homogenous Transformation under Local Communication: We develop a framework for homogenous transformation of MAS, evolving in R^n, under a local inter agent communication topology. Here we assume that some agents are the leaders, that are transformed homogenously in an n-D space. In addition, every follower agent of the MAS communicates with some local agents to update its position, in order to grasp the homogenous mapping that is prescribed by the leader agents. We show that some distance ratios that are assigned based on initial formation, if preserved, lead to asymptotic convergence of the initial formation to a final formation under a homogenous mapping.Deployment of a Random Distribution on a Desired Manifold: Deployment of agents of a MAS, moving in a plane, on to a desired curve, is a task that is considered as an application of the proposed approach. In particular, a 2-D MAS evolution problem is considered as two 1-D MAS evolution problems, where x or y coordinates of the position of all agents are modeled as points confined to move on a straight line. Then, for every coordinate of MAS evolution, bulk motion is controlled by two agents considered leaders that move independently, with rest of the follower agents motions evolving through each follower agent communicating with two adjacent agents.
Show less - Date Issued
- 2013
- Identifier
- CFE0004915, ucf:49640
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004915
- Title
- Theoretical Study of Laser Beam Quality and Pulse Shaping by Volume Bragg Gratings.
- Creator
-
Kaim, Sergiy, Zeldovich, Boris, Flitsiyan, Elena, Leuenberger, Michael, Likamwa, Patrick, University of Central Florida
- Abstract / Description
-
The theory of stretching and compressing of short light pulses by the chirped volume Bragg gratings (CBG) is reviewed based on spectral decomposition of short pulses and on the wavelength-dependent coupled wave equations. The analytic theory of diffraction efficiency of a CBG with constant chirp and approximate theory of time delay dispersion are presented. Based on those, we performed comparison of the approximate analytic results with the exact numeric coupled-wave modeling. We also study...
Show moreThe theory of stretching and compressing of short light pulses by the chirped volume Bragg gratings (CBG) is reviewed based on spectral decomposition of short pulses and on the wavelength-dependent coupled wave equations. The analytic theory of diffraction efficiency of a CBG with constant chirp and approximate theory of time delay dispersion are presented. Based on those, we performed comparison of the approximate analytic results with the exact numeric coupled-wave modeling. We also study theoretically various definitions of laser beam width in a given cross-section. Quality of the beam is characterized by the dimensionless beam propagation products (?x???_x)?? , which are different for each of the 21 definitions. We study six particular beams and introduce an axially-symmetric self-MFT (mathematical Fourier transform) function, which may be useful for the description of diffraction-quality beams. Furthermore, we discuss various saturation curves and their influence on the amplitudes of recorded gratings. Special attention is given to multiplexed volume Bragg gratings (VBG) aimed at recording of several gratings in the same volume. The best shape of a saturation curve for production of the strongest gratings is found to be the threshold-type curve. Both one-photon and two-photon absorption mechanism of recording are investigated. Finally, by means of the simulation software we investigate forced airflow cooling of a VBG heated by a laser beam. Two combinations of a setup are considered, and a number of temperature distributions and thermal deformations are obtained for different rates of airflows. Simulation results are compared to the experimental data, and show good mutual agreement.
Show less - Date Issued
- 2015
- Identifier
- CFE0005638, ucf:50210
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005638
- Title
- A Real Option Dynamic Decision (RODD) Framework for Operational Innovations.
- Creator
-
Onkham, Wilawan, Rabelo, Luis, O'Neal, Thomas, Pazour, Jennifer, Yazici, Hulya Julie, University of Central Florida
- Abstract / Description
-
Changing the business operations and adopting new operational innovations, have become key features for a business solution approach. However, there are challenges for developing innovative operations due to a lack of the proper decision analysis tools, lack of understanding the impacts transition will have on operational models, and the time limits of the innovation life cycle. The cases of business failure in operational innovation (i.e. Eastman Kodak Company and Borders Group Inc.,)...
Show moreChanging the business operations and adopting new operational innovations, have become key features for a business solution approach. However, there are challenges for developing innovative operations due to a lack of the proper decision analysis tools, lack of understanding the impacts transition will have on operational models, and the time limits of the innovation life cycle. The cases of business failure in operational innovation (i.e. Eastman Kodak Company and Borders Group Inc.,) support the need for an investment decision framework. This research aims to develop a Real Option Dynamic Decision (RODD) framework for decision making, to support decision makers for operational innovation investments. This development will help the business/organization to recognize the need for change in operations, and quickly respond to market threats and customer needs. The RODD framework is developed by integrating a strategic investment method (Real Options Analysis), management transition evaluation (Matrix of Change), competitiveness evaluation (Lotka-Volterra), and dynamic behavior modeling (System Dynamics Modeling) to analyze the feasibility of the transformation, and to assess return on investment of new operation schemes. Two case studies are used: United Parcel Service of America, Inc., and Firefighting Operations to validate the RODD framework. The results show that the benefits of this decision-making framework are (1) to provide increased flexibility, improved predictions, and more information to decision makers; (2) to assess the value alternative option with regards to uncertainty and competitiveness; (3) to reduce complexity; and (4) to gain a new understanding of operational innovations.
Show less - Date Issued
- 2013
- Identifier
- CFE0005039, ucf:50002
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005039
