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- Title
- Spatial Models with Specific Error Structures.
- Creator
-
Adu, Nathaniel, Richardson, Gary, Mohapatra, Ram, Song, Zixia, Lang, Sheau-Dong, University of Central Florida
- Abstract / Description
-
The purpose of this dissertation is to study the first order autoregressive model in the spatial context with specific error structures. We begin by supposing that the error structure has a long memory in both the i and the j components. Whenever the model parameters alpha and beta equal one, the limiting distribution of the sequence of normalized Fourier coefficients of the spatial process is shown to be a function of a two parameter fractional Brownian sheet. This result is used to find the...
Show moreThe purpose of this dissertation is to study the first order autoregressive model in the spatial context with specific error structures. We begin by supposing that the error structure has a long memory in both the i and the j components. Whenever the model parameters alpha and beta equal one, the limiting distribution of the sequence of normalized Fourier coefficients of the spatial process is shown to be a function of a two parameter fractional Brownian sheet. This result is used to find the limiting distribution of the periodogram ordinate of the spatial process under the null hypothesis that alpha equals one and beta equals one. We then give the limiting distribution of the normalized Fourier coefficients of the spatial process for both a moving average and autoregressive error structure. Two cases of autoregressive errors are considered. The first error model is autoregressive in one component and the second is autoregressive in both components. We show that the normalizing factor needed to ensure convergence in distribution of the sequence of Fourier coefficients is different in the moving average case, and the two autoregressive cases. In other words, the normalizing factor differs in each of these three cases.Finally, a specific case of the functional central limit theorem in the spatial setting is stated and proved. The assumptions made here are placed on the autocovariance functions. We then discuss some specific examples and provide a test statistics based on the periodogram ordinate.
Show less - Date Issued
- 2019
- Identifier
- CFE0007772, ucf:52385
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007772
- Title
- DAMAGE MODELING METHOD FOR TURBINE COMPRESSOR BLADE TUNING.
- Creator
-
Afanasiev, Gennadiy, Nicholson, David, University of Central Florida
- Abstract / Description
-
The thesis presents a method of evaluation for blade damage in Combustion Turbine Compressor Section. This method involves use of multiple domains within a single Finite Element Model to predict the effect of damage on the blade properties. This approach offers significant time and effort savings when compared to traditional evaluation methods of similar problems. It is demonstrated via examples that the "multi-domain" modeling approach yields acceptable accuracy results. The economical...
Show moreThe thesis presents a method of evaluation for blade damage in Combustion Turbine Compressor Section. This method involves use of multiple domains within a single Finite Element Model to predict the effect of damage on the blade properties. This approach offers significant time and effort savings when compared to traditional evaluation methods of similar problems. It is demonstrated via examples that the "multi-domain" modeling approach yields acceptable accuracy results. The economical implications of described method are readily applicable to both the industrial and the aerospace Combustion Turbine fields. It is economically impractical to replace the blade at each damage occurrence. However, the evaluation time involved in making associated decisions can be extensive if traditional methods of evaluation are used. The specific contributions of this study are twofold: 1. Time savings during evaluation 2. Compressor Blades may be returned to service which are otherwise replaced
Show less - Date Issued
- 2004
- Identifier
- CFE0000009, ucf:46099
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000009
- Title
- Rock-a-Buy Baby: Consumerism by New, First-Time Mothers.
- Creator
-
Afflerback, Sara, Grauerholz, Elizabeth, Carter, Shannon, Koontz, Amanda, University of Central Florida
- Abstract / Description
-
Rock-a-Buy Baby: Consumerism by New, First-Time Mothers, is the first known sociological exploration of need-based consumption for babies, despite the baby gear industry being a $6-billion-dollar business (whattoexpect.com). Data stemmed from qualitative, semi-structured interviews with new, first-time mothers (3 months (-) 1 year postpartum) conducted within participants' households. The insights gained from the present study tell us a great deal about the (")needs(") that predominantly...
Show moreRock-a-Buy Baby: Consumerism by New, First-Time Mothers, is the first known sociological exploration of need-based consumption for babies, despite the baby gear industry being a $6-billion-dollar business (whattoexpect.com). Data stemmed from qualitative, semi-structured interviews with new, first-time mothers (3 months (-) 1 year postpartum) conducted within participants' households. The insights gained from the present study tell us a great deal about the (")needs(") that predominantly white, middle-class mothers socially constructed in anticipation of their first child, and the consumptive behaviors used to accomplish these "needs." Respondents had turned to similar resources (other mothers, online forums, consumer reports, books, magazines, etc.) to help them construct (")need(") and formulate decisions among commodities. Provided they were relying on comparable, if not overlapping, bodies of knowledge, mothers' narratives about consumer (")need(") were often congruent. Additionally, the ways expectant mothers accumulated items are ritualized and made tradition. The baby shower and gift registration process (which all of my respondents participated in to some variation) are social constructions; these practices, which are so strongly tied to consumption, also constituted reality for mothers, and inevitably, their babies.
Show less - Date Issued
- 2012
- Identifier
- CFE0004258, ucf:49502
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004258
- Title
- Sunshine and sport in Florida and the West Indies.
- Creator
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Aflalo, Frederick G. (Frederick George), 1870-1918, PALMM (Project)
- Abstract / Description
-
Detailed account of the author's sport fishing trip to Florida and the West Indies during the early 1900's.
- Date Issued
- 1907
- Identifier
- DP0006275
- Format
- E-book
- PURL
- http://purl.flvc.org/ucf/fd/DP0006275
- Title
- A Study of the Influence of the Restorative Justice Model on Out-of-School Suspensions in a Large Urban School District.
- Creator
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Agard, Brian, Johnson, Jerry, Doherty, Walter, Baldwin, Lee, Larsen, James, University of Central Florida
- Abstract / Description
-
The purpose of this quantitative study was to investigate whether the Restorative Justice model influenced the number of days that students were suspended out-of-school or the number of out-of-school suspension incidents. In addition, the researcher analyzed whether the Restorative Justice model had different impacts for the subgroups of students qualifying for free and reduced lunch (FRL), English Learners (EL), students qualifying for exceptional student education services (ESE), and three...
Show moreThe purpose of this quantitative study was to investigate whether the Restorative Justice model influenced the number of days that students were suspended out-of-school or the number of out-of-school suspension incidents. In addition, the researcher analyzed whether the Restorative Justice model had different impacts for the subgroups of students qualifying for free and reduced lunch (FRL), English Learners (EL), students qualifying for exceptional student education services (ESE), and three ethnic subgroups (White, Black, and Hispanic) in an urban school district in Central Florida for the sixth-, seventh-, and eighth-grade students for the seven school years from 2010-2011 to 2016-2017. Primary data analysis strategies were descriptive statistics and visual analyses utilizing an interrupted time series design. The findings can be helpful in informing decision makers if the Restorative Justice model is having a positive influence on decreasing out-of-school suspension incidents and/or out-of-school suspension days.
Show less - Date Issued
- 2018
- Identifier
- CFE0007144, ucf:52325
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007144
- Title
- PREPARATION AND CHARACTERISATION OF STABILIZED NAFION/PHOSPHOTUNGSTIC ACID COMPOSITE MEMBRANES FOR PROTON EXCHANGE MEMBRANE FUEL CELL (PEMFC) AUTOMOBILE ENGINES.
- Creator
-
Agarwal, Rohit, Fenton, James, University of Central Florida
- Abstract / Description
-
Membrane durability is one of the limiting factors for proton exchange membrane fuel cell (PEMFC) commercialisation by limiting the lifetime of the membrane via electrochemical / mechanical / thermal degradation. Lower internal humidity in the membrane at high temperature (>100 oC) and low relative humidity (25-50 %RH) operating conditions leads to increased resistance, lowering of performance and higher degradation rate. One of the promising candidates is composite proton exchange membranes ...
Show moreMembrane durability is one of the limiting factors for proton exchange membrane fuel cell (PEMFC) commercialisation by limiting the lifetime of the membrane via electrochemical / mechanical / thermal degradation. Lower internal humidity in the membrane at high temperature (>100 oC) and low relative humidity (25-50 %RH) operating conditions leads to increased resistance, lowering of performance and higher degradation rate. One of the promising candidates is composite proton exchange membranes (CPEMs) which have heteropoly acid (HPA) e.g. Phosphotungstic acid (PTA) doped throughout the Nafion® matrix. HPA is primarily responsible for carrying intrinsic water which reduces the external water dependence. The role of relative humidity during membrane casting was studied using surface analysis tools such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Thermo-gravimetric analysis (TGA), and Scanning electron microscopy (SEM) / Energy dispersive spectrometer (EDS). Membrane casting at lower relative humidity (30% approx.) results in finer size, and better PTA incorporation in the composite membrane. The effect of increase in PTA concentration in the Nafion matrix was studied with regards to conductivity, performance and durability. In-plane conductivity measurements were performed at 80 oC and 120 oC. During theses measurements, relative humidity was varied from 20% to 100% RH. Membrane conductivity invariably increases on increasing the relative humidity or operating temperature of the cell. Membrane conductivity increases with increasing PTA content from 3% to 25% PTA but never reaches the conductivity of membrane with 0% PTA. Possible explanation might be the role of cesium in PTA stabilisation process. Cesium forms a complex compound with PTA inside host matrix, rendering the PTA incapable of holding water. In plane conductivity measurements only measure surface conductivity, hence another reason might be the existence of a PTA skin on the membrane surface which is not truly representative of the whole membrane. XRD revealed that the structure of the composite membrane changes significantly on addition of PTA. Membrane with 3% PTA has structure similar to Nafion® and does not exhibit the characteristic 25o and 35o 2Ө peaks while membrane with 15% PTA and 25% PTA have strong characteristic PTA peaks. Also the membrane structure with 25% PTA matches well with that of PTA.6H2O. By applying the Scherer formula, PTA particle size was calculated from Full width half maximum (FWHM) studies at 17o 2Ө peak of the membranes. Particles coalesce on increasing the PTA concentration in the membrane leading to larger particles but still all particles were in nanometer range. Also the FWHM of membranes decreased at 17o 2Ө peak on increasing the PTA concentration, leading to higher crystallinity in the membrane. Structure analysis by FTIR indicated increase in PTA signature intensity dips, as the PTA concentration in membrane increases from 0-25%. Also by FTIR studies, it was found that some PTA is lost during the processing step as shown by comparison of as cast and protonated spectra. Possible reasoning might be that some amount of PTA does not gets cesium stabilized which gets leached away during processing. TGA studies were performed which showed no signs of early thermal degradation (temperature >300 oC); hence the assumption that all membranes are thermally robust for intended fuel cell applications. The membranes with different amounts of PTA were then catalyst coated and tested for 100-hour at open circuit voltage (OCV), 30% RH and 90 oC. By increasing the PTA in the host Nafion® matrix, the percent change in fuel crossover decreases, percent change in ECA increases, cathode fluoride emission rate decreases, and percent change in OCV decreases after the 100 hour test. Possible reasons for decreasing percentage of fuel crossover might be the increased internal humidity of the membrane due to increasing PTA incorporation. It is reported that during higher relative humidity operation, there is decrease in fuel crossover rate. Increasing ECA percentage loss might be due to the fact that HPA in the membrane can get adsorbed on the catalyst sites, rendering the sites inactive for redox reaction. Decrease in cathode fluorine emission rate (FER) might be due to the fact that there is more water available internally in the membrane as compared to Nafion®. It is reported that at higher relative humidity, FER decreases. ECA and crossover both contribute to the OCV losses. Higher component of OCV is crossover loss, which results in mixed potentials. Hence decreasing percentage of crossover might be the reason behind the decreasing OCV loss. Initial performance of fuel cell increases with increasing PTA concentration, but after the 100 hour test, higher PTA membrane exhibited highest performance loss. Increasing initial fuel cell performance can be due to the lowering of resistance due to PTA addition. Increasing ECA losses might be responsible for the increasing performance losses on adding more PTA to host membrane.
Show less - Date Issued
- 2008
- Identifier
- CFE0002486, ucf:47677
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002486
- Title
- Seismic Response of Moment Resisting Frames Coupled with Rocking Walls.
- Creator
-
Aghagholizadeh, Mehrdad, Makris, Nicos, Catbas, Necati, Mackie, Kevin, Kauffman, Jeffrey L., University of Central Florida
- Abstract / Description
-
This study investigates the inelastic response of yielding structures coupled with rocking walls. This topic is of major significance in the design of tall moment-resisting buildings, since during recent major earthquakes several tall, moment-resisting frames that had been designed in an accordance to the existing seismic code provisions, exhibited a weak-story failure. Utilization of this structural system can help reducing maximum story drifts, prevents weak story failure and minimize...
Show moreThis study investigates the inelastic response of yielding structures coupled with rocking walls. This topic is of major significance in the design of tall moment-resisting buildings, since during recent major earthquakes several tall, moment-resisting frames that had been designed in an accordance to the existing seismic code provisions, exhibited a weak-story failure. Utilization of this structural system can help reducing maximum story drifts, prevents weak story failure and minimize residual deformation of the structure. This study first examines different configurations of both stepping rocking walls and pinned rocking walls that have been reported in the literature.Next, effect of additional vertical tendons or vertical damping devices in maximum response of the system is investigated. This research first derives the nonlinear equations of motion of a yieldingoscillator coupled with a rocking wall and the dependability of the one-degree of freedom idealization is validated against the nonlinear time-history response analysis of a 9-story moment-resisting frame coupled with a rocking wall. This research finally concludes that, stepping wall suppresses peak and permanent displacements, with the heavier wall being most effective. In contrast, the pinned rocking wall increases in general the peak inelastic displacements and the permanent displacements. While, the coupling of weak building frames with rocking walls is an efficient strategy that controls inelastic deformations by enforcing a uniform interstory-drift distribution, therefore, avoiding mid-story failures, the study shows that even for medium-rise buildings the effect of vertical tendons on the inelastic structural response is marginal, except for increasing the vertical reactions at the pivoting points of the rocking wall. Additionally, The SDOF idealization presented in this study compares satisfactory with finite-element analysis of a 9-story steel SAC building coupled with a stepping rocking wall; therefore, the SDOF idealization can be used with confidence for preliminary analysis and design.
Show less - Date Issued
- 2018
- Identifier
- CFE0007301, ucf:52157
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007301
- Title
- DETERMINANTS OF PRODUCTIVITY IN HOSPITAL-BASED RURAL HEALTH CLINICS: A GROWTH CURVE MODELING APPROACH.
- Creator
-
Agiro, Abiy, Wan, Thomas, University of Central Florida
- Abstract / Description
-
The Patient Protection and Affordable Care Act of 2010 expanded rural Medicaid and Medicare coverage. However, different vehicles of delivering care (e.g., hospitals, health clinics, etc.) have differing organizational capacity that may or may not enable them to overcome the challenges of expanded provision. Consequently, this research employed structural contingency and organizational performance models to investigate the impact of organizational factors on productivity growth, while...
Show moreThe Patient Protection and Affordable Care Act of 2010 expanded rural Medicaid and Medicare coverage. However, different vehicles of delivering care (e.g., hospitals, health clinics, etc.) have differing organizational capacity that may or may not enable them to overcome the challenges of expanded provision. Consequently, this research employed structural contingency and organizational performance models to investigate the impact of organizational factors on productivity growth, while recognizing that contextual factors also affect the delivery of care. Latent growth curve modeling was used to study a national panel of 708 U.S. hospital-based Rural Health Clinics for the years 2005 to 2008. Productivity was measured through dynamic slacks-based data envelopment analyses. Unconditional and conditional linear growth curve models were fitted to data. Findings revealed that 1) hospital-based clinics with higher baseline levels of productivity in 2005 had a slower rate of growth in productivity for the years 2006 to 2008, 2) hospital-based clinics with physicians had significantly higher productivity, 3) hospital-based clinics in urban focused areas had significantly higher productivity, 4) newer hospital-based clinics had significantly higher productivity, and 5) prospective payment system was negatively related to the rate of change in productivity growth. Organizational and contextual factors included in this study significantly explained initial differences in productivity but were unable to explain productivity growth.Future research could improve the study by 1) including additional explanatory variables, such as the use of technology and disease management programs, 2) adjusting productivity measures by case mix measures, and 3) conducting truncated panel data regression with Monte Carlo simulation.
Show less - Date Issued
- 2011
- Identifier
- CFE0003912, ucf:48753
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003912
- Title
- COLLEGE STUDENTS' WELL BEING: THE ROLE OF PARENT-COLLEGE STUDENT EXPECTATION DISCREPANCIES AND COMMUNICATION.
- Creator
-
Agliata, Allison, Renk, Kimberly, University of Central Florida
- Abstract / Description
-
Parental influence on college students' well being is underestimated frequently in the developmental literature. College students often set social and academic goals according to their perception of what their parents expect from them. The discrepancy between college students' performance and their perceptions of parents' expectations can impact their quality of life. The purpose of this study was to examine various parent-college student expectation discrepancies and communication levels as...
Show moreParental influence on college students' well being is underestimated frequently in the developmental literature. College students often set social and academic goals according to their perception of what their parents expect from them. The discrepancy between college students' performance and their perceptions of parents' expectations can impact their quality of life. The purpose of this study was to examine various parent-college student expectation discrepancies and communication levels as predictors for college students' psychological well being. Results revealed that college students reported experiencing higher levels of anger, depression, and anxiety and lower levels of self-esteem and college adjustment when higher expectation-performance discrepancies were present. Results also indicated that a higher perceived level of communication, particularly by the college student, served as a predictor of distress and was related to lower levels of affective distress and higher levels of self-esteem and college adjustment. Such findings underscore the importance of teaching assertive communication skills to college students and their parents as a means of diminishing the deleterious effects of perceiving one another inaccurately.
Show less - Date Issued
- 2005
- Identifier
- CFE0000556, ucf:46424
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000556
- Title
- ASSESSING MALE BODY IMAGE: DEVELOPMENT AND VALIDATION OF THE APPEARANCE INVENTORY FOR MEN (AIM).
- Creator
-
Agliata, Daniel, Dunn, Stacey, University of Central Florida
- Abstract / Description
-
Despite evidence suggesting that appearance dissatisfaction among men is on the rise, a void in appropriate forms of body image assessment for males remains. The current study reviews the literature on male body image, identifying the shortcomings and limitations of prior research, and introduces a psychometrically sound, male-specific body image assessment. An initial item-generation study was used to poll 253 males to inquire about their concerns, emotions, behaviors, and related body image...
Show moreDespite evidence suggesting that appearance dissatisfaction among men is on the rise, a void in appropriate forms of body image assessment for males remains. The current study reviews the literature on male body image, identifying the shortcomings and limitations of prior research, and introduces a psychometrically sound, male-specific body image assessment. An initial item-generation study was used to poll 253 males to inquire about their concerns, emotions, behaviors, and related body image topics to be sorted and synthesized into items for scale inclusion. The newly developed Appearance Inventory for Men (AIM) was then administered to 330 males and submitted to exploratory factor analyses, revealing a relatively stable three-factor structure. Weight-Focus (WF), Muscle Focus (MF), and Appearance Motivation (AM) factors emerged, all with good internal consistency and convergent, discriminant, and construct validity. Two additional psychometrically sound subscales were included in the final AIM that assess body area satisfaction for men (Key Attributes of Muscularity; KAM) and the common Strategies for Appearance Management (SAM). Future research and clinical implications are discussed, as are the directions for continued validation of this unique, yet much needed male-specific body image assessment tool.
Show less - Date Issued
- 2005
- Identifier
- CFE0000564, ucf:46430
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000564
- Title
- Expression of Trichoderma reesei (&)#223;-Mannanase in Tobacco Chloroplasts and its Utilization in Lignocellulosic Woody Biomass Hydrolysis.
- Creator
-
Agrawal, Pankaj, Daniell, Henry, Kolattukudy, Pappachan, Self, William, University of Central Florida
- Abstract / Description
-
Lignocellulosic ethanol offers a promising alternative to conventional fossil fuels. One among the major limitations in the lignocellulosic biomass hydrolysis is unavailability of efficient and environmentally biomass degrading technologies. Plant-based production of these enzymes on large scale offers a cost effective solution. Cellulases, hemicellulases including mannanases and other accessory enzymes are required for conversion of lignocellulosic biomass into fermentable sugars. ?...
Show moreLignocellulosic ethanol offers a promising alternative to conventional fossil fuels. One among the major limitations in the lignocellulosic biomass hydrolysis is unavailability of efficient and environmentally biomass degrading technologies. Plant-based production of these enzymes on large scale offers a cost effective solution. Cellulases, hemicellulases including mannanases and other accessory enzymes are required for conversion of lignocellulosic biomass into fermentable sugars. ?-mannanase catalyzes endo-hydrolysis of the mannan backbone, a major constituent of woody biomass. In this study, man1 gene encoding ?-mannanase was isolated from Trichoderma reesei and expressed via the chloroplast genome. PCR and Southern hybridization analysis confirmed the site-specific transgene integration into the tobacco chloroplast genomes and homoplasmy. Transplastomic plants were fertile and set viable seeds. Germination of seeds showed inheritance of transgenes into the progeny without Mendelian segregation. Expression of the endo-?-mannanase gene for the first time in plants facilitated its characterization for use in enhanced lignocellulosic biomass hydrolysis. Gel diffusion assay for endo-?-mannanase showed the zone of clearance confirming functionality of chloroplast-derived mannanase. Endo-?-mannanase expression levels reached up to 25 units per gram of leaf (fresh weight). Chloroplast-derived mannanase had higher temperature stability (40 (&)deg;C to 70 (&)deg;C) and wider pH optima (pH 3.0 to 7.0) than E.coli enzyme extracts. Plant crude extracts showed 6-7 fold higher enzyme activity than E.coli extracts due to the formation of disulfide bonds in chloroplasts, thereby facilitating their direct utilization in enzyme cocktails without any purification. Chloroplast-derived mannanase when added to the enzyme cocktail containing a combination of different enzymes yielded 20% more glucose equivalents from pinewood than the cocktail without mannanase. Our results demonstrate that chloroplast-derived mannanase is an important component of enzymatic cocktail for woody biomass hydrolysis and should provide a cost-effective solution for its diverse applications in the paper, oil, pharmaceutical, coffee and detergent industries.
Show less - Date Issued
- 2011
- Identifier
- CFE0004467, ucf:49309
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004467
- Title
- TWO CONCEPTIONS OF THE MIND.
- Creator
-
Aguda, Benjamin, Gallagher, Shaun, University of Central Florida
- Abstract / Description
-
Since the cognitive revolution during the last century the mind has been conceived of as being computer-like. Like a computer, the brain was assumed to be a physical structure (hardware) upon which a computational mind (software) was built. The mind was seen as a collection of independent programs which each have their own specific tasks, or modules. These modules took sensory input "data" and transduced it into language-like representations which were used in mental computations. Recently, a...
Show moreSince the cognitive revolution during the last century the mind has been conceived of as being computer-like. Like a computer, the brain was assumed to be a physical structure (hardware) upon which a computational mind (software) was built. The mind was seen as a collection of independent programs which each have their own specific tasks, or modules. These modules took sensory input "data" and transduced it into language-like representations which were used in mental computations. Recently, a new conception of the mind has developed, grounded cognition. According to this model, sensory stimulus is saved in the original format in which it was received and recalled using association mechanisms. Rather than representations being language-like they are instead multimodal. The manipulation of these multimodal representations requires processing distributed throughout the brain. A new holistic model for mental architecture has developed in which the concerted activity of the brain's modal systems produces functional systems which are intimately codependent with one another. The purpose of this thesis is to explore both the modular and multimodal theories of mental architecture. Each will be described in detail along with their supporting paradigms, cognitivism and grounded cognition. After my expositions I will offer support for my own position regarding these two theories before suggesting avenues for future research.
Show less - Date Issued
- 2011
- Identifier
- CFH0003784, ucf:44765
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0003784
- Title
- REAL ESTATE LAW:THE AMERICAN DREAM TRANSFIGURED INTO THE AMERICAN MORTGAGE CRISIS.
- Creator
-
Aguiar, Maricruz, Naccarato-Fromang, Gina, University of Central Florida
- Abstract / Description
-
Real Estate law is the body of rules and regulations with legal codes that concern ownership, development and transactions. Real Estate has grown to be one of the main contributors to the nation's financial system. For decades, the housing market has been such an integral part of the economy. Unfortunately, in the beginning of the twenty-first century lax regulatory oversight led the nation to an economic collapse. Indeed, federal, state and local governments have become heavily involved in...
Show moreReal Estate law is the body of rules and regulations with legal codes that concern ownership, development and transactions. Real Estate has grown to be one of the main contributors to the nation's financial system. For decades, the housing market has been such an integral part of the economy. Unfortunately, in the beginning of the twenty-first century lax regulatory oversight led the nation to an economic collapse. Indeed, federal, state and local governments have become heavily involved in solving the downward spiral in the economy. This research focuses on the mortgage crisis in order to show how Real Estate law can in fact, restore the economy when the government has a balance between regulations and market discipline. The intent of this thesis was to study the occurrence of the mortgage crisis, the regulatory authorities and the legal effects of the housing market. Through the analysis of case law and statutes, data, previous recessions, and economic indicators, this thesis examines the key factors in our legal system that should drive reform in our economy. Results suggested that greater efforts to a regulatory structure generate a secure financial system. Thus, the purpose of this thesis is not only to solve our current mortgage crisis but also to mitigate or prevent future crises.
Show less - Date Issued
- 2012
- Identifier
- CFH0004215, ucf:44927
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004215
- Title
- AN INVESTIGATION OF THE EFFECTIVENESS OF COMPUTER-ASSISTED BIOFEEDBACK FOR STUDENTS DIAGNOSED AS HAVING AUTISM SPECTRUM DISORDER: THE RELATIONSHIP BETWEEN THE USE OF COMPUTER-ASSISTED BIOFEEDBACK AND ON-TASK BEHAVIOR.
- Creator
-
Aguinaga, Nancy, Cross, Lee, University of Central Florida
- Abstract / Description
-
Using a single-subject multiple baseline design across participants, this study examined the impact of computer-assisted biofeedback to promote engagement of students diagnosed as having autism spectrum disorder. The study was conducted in a public school classroom setting. Specifically the on-task behavior during an individualized academic activity was investigated. Three 9-10 year old children participated in the study. In the baseline phase, data was collected on speed to engagement and...
Show moreUsing a single-subject multiple baseline design across participants, this study examined the impact of computer-assisted biofeedback to promote engagement of students diagnosed as having autism spectrum disorder. The study was conducted in a public school classroom setting. Specifically the on-task behavior during an individualized academic activity was investigated. Three 9-10 year old children participated in the study. In the baseline phase, data was collected on speed to engagement and percentage of time on-task during an academic activity. A 15-second momentary time sampling procedure was used for a 5 minute session each day of the week for a five week period to measure the participant's engagement. In the intervention phase, the participants completed a three to four minute computer-assisted biofeedback session prior to the academic activity and collection of data on engagement. In addition, data were collected on performance level of the academic activity. Data were also collected on educator and parent perception of generalization of self-regulation of behavior. The data suggest: (a) speed to engagement increased when using a computer-assisted biofeedback program for all participants; (b) time on-task improved over baseline conditions for all participants; (c) academic achievement was impacted by computer-assisted biofeedback for one participant; and (d) educators perceived a generalization of self-regulation of behavior, while parents did not indicate any generalization of self-regulation of behavior occurred in the home environment.
Show less - Date Issued
- 2006
- Identifier
- CFE0001260, ucf:46888
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001260
- Title
- RESILIENCY IN ADOLESCENT COLLEGE STUDENTS.
- Creator
-
Ahern, Nancy, Byers, Jacqueline, University of Central Florida
- Abstract / Description
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The construct of resilience has gained considerable attention over the last four decades since researchers observed that children and youth could cope and adapt in spite of adversity. Resilience involves a dynamic process involving an interaction between both risk and protective processes, internal and external to the individual, that can modify the effects of an adverse life event. Adolescence is considered to be a period of vulnerability for most individuals as they often partake in high...
Show moreThe construct of resilience has gained considerable attention over the last four decades since researchers observed that children and youth could cope and adapt in spite of adversity. Resilience involves a dynamic process involving an interaction between both risk and protective processes, internal and external to the individual, that can modify the effects of an adverse life event. Adolescence is considered to be a period of vulnerability for most individuals as they often partake in high risk behaviors. Further, those individuals who are in their early college years are faced with the developmental challenges of this life phase which can be complicated by a variety of stresses. Investigating resilience in college students is of great importance as these adolescents may incur additional stress as they make the transition to adulthood. Empirical evidence indicates that resilience is dynamic, developmental in nature, and interactive with one's environment. A variety of variables have been studied to clarify the concept of resilience in adolescents, yet there continues to be inconsistent findings. Although there is an abundance of literature regarding adolescent resilience, little is known about this process in the healthy well-adjusted adolescent college student. Additionally there are inconsistencies in reported findings about whether resilience is a healthy state. There is also evidence in the literature that contradictions exist regarding the effect of social support on this process. After review of the psychometric properties of existing instruments, the Resilience Scale was determined to have the best reliability and validity use for the study of resilience in the adolescent population. An exploratory model testing design was used to explore the relationships among a set of variables, including personal characteristics, levels of stress, high risk behaviors, and levels of resilience in adolescents ages 18 to 20 years. Institutional Review Board approval was obtained prior to data collection. The study participants attended a community college and met the sample selection criteria. A convenience sampling plan was used. Recruitment of participants followed the college protocol for contacting professors teaching general education classes during the planned data collection time. The study measures included a demographic questionnaire, two perceived stress visual analog scales, the Health Behaviors Questionnaire, and the Resilience Scale. Descriptive statistics were computed for all variables for the total sample (n=166) and recoding performed as needed by the instruments. Model testing was performed using correlations, hierarchical multiple regression, and path analysis to identify the strongest predictive variables. The strongest predictive model was personal characteristics and Health Behaviors Questionnaire Emotional Risk to the visual analog scale Stress in General (R2 = .519, F = 3.13, p = .000). This model was used for path analysis and the significant variables were ethnicity (standardized beta coefficients of .165, p = .036) and Health Behaviors Questionnaire Emotional Risk (standardized beta coefficients of .567, p = .000). These findings are important for health care providers to use as a basis for driving interventions to optimize resilience and reduce stress in adolescents. Further research should focus on ways to enhance coping and adaptation in an effort to reduce emotional risks which potentially increase stress in similar populations. Research regarding resilience and stress can further be expanded to the study of additional populations at risk, including adults and others such as nursing students, war veterans, and disaster victims.
Show less - Date Issued
- 2007
- Identifier
- CFE0001627, ucf:47177
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001627
- Title
- DESIGN FOR AUDITORY DISPLAYS: IDENTIFYING TEMPORAL AND SPATIAL INFORMATION CONVEYANCE PRINCIPLES.
- Creator
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Ahmad, Ali, Stanney, Kay, University of Central Florida
- Abstract / Description
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Designing auditory interfaces is a challenge for current human-systems developers. This is largely due to a lack of theoretical guidance for directing how best to use sounds in today's visually-rich graphical user interfaces. This dissertation provided a framework for guiding the design of audio interfaces to enhance human-systems performance. This doctoral research involved reviewing the literature on conveying temporal and spatial information using audio, using this knowledge to build...
Show moreDesigning auditory interfaces is a challenge for current human-systems developers. This is largely due to a lack of theoretical guidance for directing how best to use sounds in today's visually-rich graphical user interfaces. This dissertation provided a framework for guiding the design of audio interfaces to enhance human-systems performance. This doctoral research involved reviewing the literature on conveying temporal and spatial information using audio, using this knowledge to build three theoretical models to aid the design of auditory interfaces, and empirically validating select components of the models. The three models included an audio integration model that outlines an end-to-end process for adding sounds to interactive interfaces, a temporal audio model that provides a framework for guiding the timing for integration of these sounds to meet human performance objectives, and a spatial audio model that provides a framework for adding spatialization cues to interface sounds. Each model is coupled with a set of design guidelines theorized from the literature, thus combined, the developed models put forward a structured process for integrating sounds in interactive interfaces. The developed models were subjected to a three phase validation process that included review by Subject Matter Experts (SMEs) to assess the face validity of the developed models and two empirical studies. For the SME review, which assessed the utility of the developed models and identified opportunities for improvement, a panel of three audio experts was selected to respond to a Strengths, Weaknesses, Opportunities, and Threats (SWOT) validation questionnaire. Based on the SWOT analysis, the main strengths of the models included that they provide a systematic approach to auditory display design and that they integrate a wide variety of knowledge sources in a concise manner. The main weaknesses of the models included the lack of a structured process for amending the models with new principles, some branches were not considered parallel or completely distinct, and lack of guidance on selecting interface sounds. The main opportunity identified by the experts was the ability of the models to provide a seminal body of knowledge that can be used for building and validating auditory display designs. The main threats identified by the experts were that users may not know where to start and end with each model, the models may not provide comprehensive coverage of all uses of auditory displays, and the models may act as a restrictive influence on designers or they may be used inappropriately. Based on the SWOT analysis results, several changes were made to the models prior to the empirical studies. Two empirical evaluation studies were conducted to test the theorized design principles derived from the revised models. The first study focused on assessing the utility of audio cues to train a temporal pacing task and the second study combined both temporal (i.e., pace) and spatial audio information, with a focus on examining integration issues. In the pace study, there were four different auditory conditions used for training pace: 1) a metronome, 2) non-spatial auditory earcons, 3) a spatialized auditory earcon, and 4) no audio cues for pace training. Sixty-eight people participated in the study. A pre- post between subjects experimental design was used, with eight training trials. The measure used for assessing pace performance was the average deviation from a predetermined desired pace. The results demonstrated that a metronome was not effective in training participants to maintain a desired pace, while, spatial and non-spatial earcons were effective strategies for pace training. Moreover, an examination of post-training performance as compared to pre-training suggested some transfer of learning. Design guidelines were extracted for integrating auditory cues for pace training tasks in virtual environments. In the second empirical study, combined temporal (pacing) and spatial (location of entities within the environment) information were presented. There were three different spatialization conditions used: 1) high fidelity using subjective selection of a "best-fit" head related transfer function, 2) low fidelity using a generalized head-related transfer function, and 3) no spatialization. A pre- post between subjects experimental design was used, with eight training trials. The performance measures were average deviation from desired pace and time and accuracy to complete the task. The results of the second study demonstrated that temporal, non-spatial auditory cues were effective in influencing pace while other cues were present. On the other hand, spatialized auditory cues did not result in significantly faster task completion. Based on these results, a set of design guidelines was proposed that can be used to direct the integration of spatial and temporal auditory cues for supporting training tasks in virtual environments. Taken together, the developed models and the associated guidelines provided a theoretical foundation from which to direct user-centered design of auditory interfaces.
Show less - Date Issued
- 2007
- Identifier
- CFE0001719, ucf:47317
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001719
- Title
- Blockchain-Driven Secure and Transparent Audit Logs.
- Creator
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Ahmad, Ashar, Mohaisen, David, Awad, Amro, Zhang, Wei, Posey, Clay, University of Central Florida
- Abstract / Description
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In enterprise business applications, large volumes of data are generated daily, encoding business logic and transactions. Those applications are governed by various compliance requirements, making it essential to provide audit logs to store, track, and attribute data changes. In traditional audit log systems, logs are collected and stored in a centralized medium, making them prone to various forms of attacks and manipulations, including physical access and remote vulnerability exploitation...
Show moreIn enterprise business applications, large volumes of data are generated daily, encoding business logic and transactions. Those applications are governed by various compliance requirements, making it essential to provide audit logs to store, track, and attribute data changes. In traditional audit log systems, logs are collected and stored in a centralized medium, making them prone to various forms of attacks and manipulations, including physical access and remote vulnerability exploitation attacks, and eventually allowing for unauthorized data modification, threatening the guarantees of audit logs. Moreover, such systems, and given their centralized nature, are characterized by a single point of failure. To harden the security of audit logs in enterprise business applications, in this work we explore the design space of blockchain-driven secure and transparent audit logs. We highlight the possibility of ensuring stronger security and functional properties by a generic blockchain system for audit logs, realize this generic design through BlockAudit, which addresses both security and functional requirements, optimize BlockAudit through multi-layered design in BlockTrail, and explore the design space further by assessing the functional and security properties the consensus algorithms through comprehensive evaluations. The first component of this work is BlockAudit, a design blueprint that enumerates structural, functional, and security requirements for blockchain-based audit logs. BlockAudit uses a consensus-driven approach to replicate audit logs across multiple application peers to prevent the single-point-of-failure. BlockAudit also uses the Practical Byzantine Fault Tolerance (PBFT) protocol to achieve consensus over the state of the audit log data. We evaluate the performance of BlockAudit using event-driven simulations, abstracted from IBM Hyperledger. Through the performance evaluation of BlockAudit, we pinpoint a need for high scalability and high throughput. We achieve those requirements by exploring various design optimizations to the flat structure of BlockAudit inspired by real-world application characteristics. Namely, enterprise business applications often operate across non-overlapping geographical hierarchies including cities, counties, states, and federations. Leveraging that, we applied a similar transformation to BlockAudit to fragment the flat blockchain system into layers of codependent hierarchies, capable of processing transactions in parallel. Our hierarchical design, called BlockTrail, reduced the storage and search complexity for blockchains substantially while increasing the throughput and scalability of the audit log system. We prototyped BlockTrail on a custom-built blockchain simulator and analyzed its performance under varying transactions and network sizes demonstrating its advantages over BlockAudit. A recurring limitation in both BlockAudit and BlockTrail is the use of the PBFT consensus protocol, which has high complexity and low scalability features. Moreover, the performance of our proposed designs was only evaluated in computer simulations, which sidestepped the complexities of the real-world blockchain system. To address those shortcomings, we created a generic cloud-based blockchain testbed capable of executing five well-known consensus algorithms including Proof-of-Work, Proof-of-Stake, Proof-of-Elapsed Time, Clique, and PBFT. For each consensus protocol, we instrumented our auditing system with various benchmarks to measure the latency, throughput, and scalability, highlighting the trade-off between the different protocols.
Show less - Date Issued
- 2019
- Identifier
- CFE0007773, ucf:52375
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007773
- Title
- ESTIMATION OF OCEANIC RAINFALL USING PASSIVE AND ACTIVE MEASUREMENTS FROM SEAWINDS SPACEBORNE MICROWAVE SENSOR.
- Creator
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Ahmad, Khalil, Jones, Linwood, University of Central Florida
- Abstract / Description
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The Ku band microwave remote sensor, SeaWinds, was developed at the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL). Two identical SeaWinds instruments were launched into space. The first was flown onboard NASA QuikSCAT satellite which has been orbiting the Earth since June 1999, and the second instrument flew onboard the Japanese Advanced Earth Observing Satellite II (ADEOS-II) from December 2002 till October 2003 when an irrecoverable solar panel failure...
Show moreThe Ku band microwave remote sensor, SeaWinds, was developed at the National Aeronautics and Space Administration (NASA) Jet Propulsion Laboratory (JPL). Two identical SeaWinds instruments were launched into space. The first was flown onboard NASA QuikSCAT satellite which has been orbiting the Earth since June 1999, and the second instrument flew onboard the Japanese Advanced Earth Observing Satellite II (ADEOS-II) from December 2002 till October 2003 when an irrecoverable solar panel failure caused a premature end to the ADEOS-II satellite mission. SeaWinds operates at a frequency of 13.4 GHz, and was originally designed to measure the speed and direction of the ocean surface wind vector by relating the normalized radar backscatter measurements to the near surface wind vector through a geophysical model function (GMF). In addition to the backscatter measurement capability, SeaWinds simultaneously measures the polarized radiometric emission from the surface and atmosphere, utilizing a ground signal processing algorithm known as the QuikSCAT / SeaWinds Radiometer (QRad / SRad). This dissertation presents the development and validation of a mathematical inversion algorithm that combines the simultaneous active radar backscatter and the passive microwave brightness temperatures observed by the SeaWinds sensor to retrieve the oceanic rainfall. The retrieval algorithm is statistically based, and has been developed using collocated measurements from SeaWinds, the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) rain rates, and Numerical Weather Prediction (NWP) wind fields from the National Centers for Environmental Prediction (NCEP). The oceanic rain is retrieved on a spacecraft wind vector cell (WVC) measurement grid that has a spatial resolution of 25 km. To evaluate the accuracy of the retrievals, examples of the passive-only, as well as the combined active / passive rain estimates from SeaWinds are presented, and comparisons are made with the standard TRMM rain data products. Results demonstrate that SeaWinds rain measurements are in good agreement with the independent microwave rain observations obtained from TMI. Further, by applying a threshold on the retrieved rain rates, SeaWinds rain estimates can be utilized as a rain flag. In order to evaluate the performance of the SeaWinds flag, comparisons are made with the Impact based Multidimensional Histogram (IMUDH) rain flag developed by JPL. Results emphasize the powerful rain detection capabilities of the SeaWinds retrieval algorithm. Due to its broad swath coverage, SeaWinds affords additional independent sampling of the oceanic rainfall, which may contribute to the future NASA's Precipitation Measurement Mission (PMM) objectives of improving the global sampling of oceanic rain within 3 hour windows. Also, since SeaWinds is the only sensor onboard QuikSCAT, the SeaWinds rain estimates can be used to improve the flagging of rain-contaminated oceanic wind vector retrievals. The passive-only rainfall retrieval algorithm (QRad / SRad) has been implemented by JPL as part of the level 2B (L2B) science data product, and can be obtained from the Physical Oceanography Distributed Data Archive (PO.DAAC).
Show less - Date Issued
- 2007
- Identifier
- CFE0001969, ucf:47441
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001969