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- Title
- AN IMPROVED MICROWAVE RADIATIVE TRANSFER MODEL FOR OCEAN EMISSIVITY AT HURRICANE FORCE SURFACE WIND SPEED.
- Creator
-
EL-Nimri, Salem, Jones, Linwood, University of Central Florida
- Abstract / Description
-
An electromagnetic model for predicting the microwave blackbody emission from the ocean surface under the forcing of strong surface winds in hurricanes is being developed. This ocean emissivity model will be incorporated into a larger radiative transfer model used to infer ocean surface wind speed and rain rate in hurricanes from remotely sensed radiometric brightness temperature. The model development is based on measurements obtained with the Stepped Frequency Microwave Radiometer (SFMR),...
Show moreAn electromagnetic model for predicting the microwave blackbody emission from the ocean surface under the forcing of strong surface winds in hurricanes is being developed. This ocean emissivity model will be incorporated into a larger radiative transfer model used to infer ocean surface wind speed and rain rate in hurricanes from remotely sensed radiometric brightness temperature. The model development is based on measurements obtained with the Stepped Frequency Microwave Radiometer (SFMR), which routinely flys on the National Oceanic and Atmospheric Administration's hurricane hunter aircraft. This thesis presents the methods used in the wind speed model development and validation results for wind speeds up to 70 m/sec. The ocean emissivity model relates changes in measured C-band radiometric brightness temperatures to physical changes in the ocean surface. These surface modifications are the result of the drag of surface winds that roughen the sea surface, produce waves, and create white caps and foam from the breaking waves. SFMR brightness temperature measurements from hurricane flights and independent measurements of surface wind speed are used to define empirical relationships between microwave brightness temperature and surface wind speed. The wind speed model employs statistical regression techniques to develop a physics-based ocean emissivity model dependent on geophysical parameters, such as wind speed and sea surface temperature, and observational parameters, such as electromagnetic frequency, electromagnetic polarization, and incidence angle.
Show less - Date Issued
- 2006
- Identifier
- CFE0001312, ucf:47019
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001312
- Title
- AN IMPROVED OCEAN VECTOR WINDS RETRIEVAL APPROACH USING C- AND KU-BAND SCATTEROMETER AND MULTI-FREQUENCY MICROWAVE RADIOMETER MEASUREMENTS.
- Creator
-
Alsweiss, Suleiman, Jones, W. Linwood, University of Central Florida
- Abstract / Description
-
This dissertation will specifically address the issue of improving the quality of satellite scatterometer retrieved ocean surface vector winds (OVW), especially in the presence of strong rain associated with tropical cyclones. A novel active/passive OVW retrieval algorithm is developed that corrects Ku-band scatterometer measurements for rain effects and then uses them to retrieve accurate OVW. The rain correction procedure makes use of independent information available from collocated multi...
Show moreThis dissertation will specifically address the issue of improving the quality of satellite scatterometer retrieved ocean surface vector winds (OVW), especially in the presence of strong rain associated with tropical cyclones. A novel active/passive OVW retrieval algorithm is developed that corrects Ku-band scatterometer measurements for rain effects and then uses them to retrieve accurate OVW. The rain correction procedure makes use of independent information available from collocated multi-frequency passive microwave observations provided by a companion sensor and also from simultaneous C-band scatterometer measurements. The synergy of these active and passive measurements enables improved correction for rain effects, which enhances the utility of Ku-band scatterometer measurements in extreme wind events. The OVW retrieval algorithm is based on the next generation instrument conceptual design for future US scatterometers, i.e. the Dual Frequency Scatterometer (DFS) developed by NASA's Jet Propulsion Laboratory. Under this dissertation research, an end-to-end computer simulation was developed to evaluate the performance of this active/passive technique for retrieving hurricane force winds in the presence of intense rain. High-resolution hurricane wind and precipitation fields were simulated for several scenes of Hurricane Isabel in 2003 using the Weather Research and Forecasting (WRF) Model. Using these numerical weather model environmental fields, active/passive measurements were simulated for instruments proposed for the Global Change Observation Mission- Water Cycle (GCOM-W2) satellite series planned by the Japanese Aerospace Exploration Agency. Further, the quality of the simulation was evaluated using actual hurricane measurements from the Advanced Microwave Scanning Radiometer and SeaWinds scatterometer onboard the Advanced Earth Observing Satellite-II (ADEOS-II). The analysis of these satellite data provided confidence in the capability of the simulation to generate realistic active/passive measurements at the top of the atmosphere. Results are very encouraging, and they show that the new algorithm can retrieve accurate ocean surface wind speeds in realistic hurricane conditions using the rain corrected Ku-band scatterometer measurements. They demonstrate the potential to improve wind measurements in extreme wind events for future wind scatterometry missions such as the proposed GCOM-W2.
Show less - Date Issued
- 2011
- Identifier
- CFE0003757, ucf:48774
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003757
- Title
- AN IMPROVED THERMOREGULATORY MODEL FOR COOLING GARMENT APPLICATIONS WITH TRANSIENT METABOLIC RATES.
- Creator
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Westin, Johan, Kapat, Jayanta, University of Central Florida
- Abstract / Description
-
Current state-of-the-art thermoregulatory models do not predict body temperatures with the accuracies that are required for the development of automatic cooling control in liquid cooling garment (LCG) systems. Automatic cooling control would be beneficial in a variety of space, aviation, military, and industrial environments for optimizing cooling efficiency, for making LCGs as portable and practical as possible, for alleviating the individual from manual cooling control, and for improving...
Show moreCurrent state-of-the-art thermoregulatory models do not predict body temperatures with the accuracies that are required for the development of automatic cooling control in liquid cooling garment (LCG) systems. Automatic cooling control would be beneficial in a variety of space, aviation, military, and industrial environments for optimizing cooling efficiency, for making LCGs as portable and practical as possible, for alleviating the individual from manual cooling control, and for improving thermal comfort and cognitive performance. In this study, we adopt the Fiala thermoregulatory model, which has previously demonstrated state-of-the-art predictive abilities in air environments, for use in LCG environments. We validate the numerical formulation with analytical solutions to the bioheat equation, and find our model to be accurate and stable with a variety of different grid configurations. We then compare the thermoregulatory model's tissue temperature predictions with experimental data where individuals, equipped with an LCG, exercise according to a 700 W rectangular type activity schedule. The root mean square (RMS) deviation between the model response and the mean experimental group response is 0.16°C for the rectal temperature and 0.70°C for the mean skin temperature, which is within state-of-the-art variations. However, with a mean absolute body heat storage error (e_BHS_mean) of 9.7 W·h, the model fails to satisfy the ±6.5 W·h accuracy that is required for the automatic LCG cooling control development. In order to improve model predictions, we modify the blood flow dynamics of the thermoregulatory model. Instead of using step responses to changing requirements, we introduce exponential responses to the muscle blood flow and the vasoconstriction command. We find that such modifications have an insignificant effect on temperature predictions. However, a new vasoconstriction dependency, i.e. the rate of change of hypothalamus temperature weighted by the hypothalamus error signal (DThy·dThy/dt), proves to be an important signal that governs the thermoregulatory response during conditions of simultaneously increasing core and decreasing skin temperatures, which is a common scenario in LCG environments. With the new DThy·dThy/dt dependency in the vasoconstriction command, the e_BHS_mean for the exercise period is reduced by 59% (from 12.9 W·h to 5.2 W·h). Even though the new e_BHS_mean of 5.8 W·h for the total activity schedule is within the target accuracy of ±6.5 W·h, e_BHS fails to stay within the target accuracy during the entire activity schedule. With additional improvements to the central blood pool formulation, the LCG boundary condition, and the agreement between model set-points and actual experimental initial conditions, it seems possible to achieve the strict accuracy that is needed for automatic cooling control development.
Show less - Date Issued
- 2008
- Identifier
- CFE0002460, ucf:47707
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002460
- Title
- AN IMPROVED TIGHT-BINDING MODEL FOR PHOSPHORENE.
- Creator
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DeLello, Kursti, Mucciolo, Eduardo, University of Central Florida
- Abstract / Description
-
The intent of this thesis is to improve upon previously proposed tight-binding models for one dimensional black phosphorus, or phosphorene. Previous models offer only a qualitative analysis of the band structure of phosphorene, and fail to fully realize critical elements in the electronic band structure necessary for transport calculations. In this work we propose an improved tight-binding model for phosphorene by including up to eight nearest-neighbor interactions. The efficacy of the model...
Show moreThe intent of this thesis is to improve upon previously proposed tight-binding models for one dimensional black phosphorus, or phosphorene. Previous models offer only a qualitative analysis of the band structure of phosphorene, and fail to fully realize critical elements in the electronic band structure necessary for transport calculations. In this work we propose an improved tight-binding model for phosphorene by including up to eight nearest-neighbor interactions. The efficacy of the model is verified by comparison with DFT-HSE06 calculations, and the anisotropy of the effective masses in the armchair and zigzag directions is considered.
Show less - Date Issued
- 2016
- Identifier
- CFH2000023, ucf:45597
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000023
- Title
- An Inconclusive Truth: An Evaluation of Speleothem Evidence for Climate Change as a Driver of Ancient Maya Culture Change.
- Creator
-
Goldblatt, Benjamin, Chase, Arlen, Chase, Diane, Callaghan, Michael, University of Central Florida
- Abstract / Description
-
As anthropologists who focus their scholarly attention on the past, archaeologists are interested in examining past changes in human cultures, which can include investigating the role(s) of climatic conditions in shaping them. Paleoclimatology offers the possibility of reconstructing past climates and demonstrating their variability over time, potentially contributing a great deal to archaeology. However, while paleoclimatology may lead to new discoveries about the human past, it may also...
Show moreAs anthropologists who focus their scholarly attention on the past, archaeologists are interested in examining past changes in human cultures, which can include investigating the role(s) of climatic conditions in shaping them. Paleoclimatology offers the possibility of reconstructing past climates and demonstrating their variability over time, potentially contributing a great deal to archaeology. However, while paleoclimatology may lead to new discoveries about the human past, it may also lead to new errors in interpreting it. Cave speleothems are sources of paleoclimatic data that have recently attracted attention in Mesoamerican archaeology, particularly in studies of the Maya region. In order to evaluate past uses of speleothem paleoclimatic records to support archaeological hypotheses, I will describe the strengths and weaknesses of particular datasets, evaluate the arguments that have been advanced for their broad spatial applicability, examine the science behind the spatial variability of precipitation patterns, and consider how the application of speleothem paleoclimatology to Maya archaeology might be improved upon. I hope to make clear that speleothem paleoclimatic records can potentially yield insights into the relationship(s) between Precolumbian climate change and ancient Maya culture change, but must be interpreted with the utmost caution.
Show less - Date Issued
- 2016
- Identifier
- CFE0006311, ucf:51602
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006311
- Title
- An Index to Measure Efficiency of Hospital Networks for Mass Casualty Disasters.
- Creator
-
Bull Torres, Maria, Sepulveda, Jose, Sala-Diakanda, Serge, Geiger, Christopher, Kapucu, Naim, University of Central Florida
- Abstract / Description
-
Disaster events have emphasized the importance of healthcare response activities due to the large number of victims. For instance, Hurricane Katrina in New Orleans, in 2005, and the terrorist attacks in New York City and Washington, D.C., on September 11, 2001, left thousands of wounded people. In those disasters, although hospitals had disaster plans established for more than a decade, their plans were not efficient enough to handle the chaos produced by the hurricane and terrorist attacks....
Show moreDisaster events have emphasized the importance of healthcare response activities due to the large number of victims. For instance, Hurricane Katrina in New Orleans, in 2005, and the terrorist attacks in New York City and Washington, D.C., on September 11, 2001, left thousands of wounded people. In those disasters, although hospitals had disaster plans established for more than a decade, their plans were not efficient enough to handle the chaos produced by the hurricane and terrorist attacks. Thus, the Joint Commission on Accreditation of Healthcare Organizations (JCAHO) suggested collaborative planning among hospitals that provide services to a contiguous geographic area during mass casualty disasters. However, the JCAHO does not specify a methodology to determine which hospitals should be included into these cooperative plans. As a result, the problem of selecting the right hospitals to include in exercises and drills at the county level is a common topic in the current preparedness stages. This study proposes an efficiency index to determine the efficient response of cooperative-networks among hospitals before an occurrence of mass casualty disaster. The index built in this research combines operations research techniques, and the prediction of this index used statistical analysis. The consecutive application of three different techniques: network optimization, data envelopment analysis (DEA), and regression analysis allowed to obtain a regression equation to predict efficiency in predefined hospital networks for mass casualty disasters. In order to apply the proposed methodology for creating an efficiency index, we selected the Orlando area, and we defined three disaster sizes. Then, we designed networks considering two perspectives, hub-hospital and hub-disaster networks. In both optimization network models the objective function pursued to: reduce the travel distance and the emergency department (ED) waiting time in hospitals, increase the number of services offered by hospitals in the network, and offer specialized assistance to children. The hospital network optimization generated information for 75 hospital networks in Orlando. The DEA analyzed these 75 hospital networks, or decision making units (DMU's), to estimate their comparative efficiency. Two DEAs were performed in this study. As an output variable for each DMU, the DEA-1 considered the number of survivors allocated in less than a 40 miles range. As the input variables, the DEA-1 included: (i) The number of beds available in the network; (ii) The number of hospitals available in the network; and (iii) The number of services offered by hospitals in the network. This DEA-1 allowed the assignment of an efficiency value to each of the 75 hospital networks. As output variables for each DMU, the DEA-2 considered the number of survivors allocated in less than a 40 miles range and an index for ED waiting time in the network. The input variables included in DEA-2 are (i) The number of beds available in the network; (ii) The number of hospitals available in the network; and (iii) The number of services offered by hospitals in the network. These DEA allowed the assignment of an efficiency value to each of the 75 hospital networks. This efficiency index should allow emergency planners and hospital managers to assess which hospitals should be associated in a cooperative network in order to transfer survivors. Furthermore, JCAHO could use this index to evaluate the cooperating emergency hospitals' plans.However, DEA is a complex methodology that requires significant data gathering and handling. Thus, we studied whether a simpler regression analysis would substantially yield the same results. DEA-1 can be predicted using two regression analyses, which concluded that the average distances between hospitals and the disaster locations, and the size of the disaster explain the efficiency of the hospital network. DEA-2 can be predicted using three regressions, which included size of the disaster, number of hospitals, average distance, and average ED waiting time, as predictors of hospital network efficiency. The models generated for DEA-1 and DEA-2 had a mean absolute percent error (MAPE) around 10%. Thus, the indexes developed through the regression analysis make easier the estimation of the efficiency in predefined hospital networks, generating suitable predictors of the efficiency as determined by the DEA analysis. In conclusion, network optimization, DEA, and regressions analyses can be combined to create an index of efficiency to measure the performance of predefined-hospital networks in a mass casualty disaster, validating the hypothesis of this research.Although the methodology can be applied to any county or city, the regressions proposed for predicting the efficiency of hospital network estimated by DEA can be applied only if the city studied has the same characteristics of the Orlando area. These conditions include the following: (i) networks must have a rate of services lager than 0.76; (ii) the number of survivors must be less than 47% of the bed capacity EDs of the area studied; (iii) all hospitals in the network must have ED and they must be located in less than 48 miles range from the disaster sites, and (iv) EDs should not have more than 60 minutes of waiting time.The proposed methodology, in special the efficiency index, support the operational objectives of the 2012 ESF#8 for Florida State to handle risk and response capabilities conducting and participating in training and exercises to test and improve plans and procedures in the health response.
Show less - Date Issued
- 2012
- Identifier
- CFE0004524, ucf:49290
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004524
- Title
- An Industrial Audiological Approach to Design and Construction of Enclosures for Control of Noise.
- Creator
-
Smart, Dale G., Mullin, Thomas A., Social Sciences
- Abstract / Description
-
Florida Technological University College of Social Sciences Thesis
- Date Issued
- 1975
- Identifier
- CFR0011993, ucf:53084
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0011993
- Title
- AN INQUIRY INTO DISCOURSE CHOICES AS INDICATORS OF GENDER ATTITUDES IN A NON-PROFIT CONSERVATIVE CHRISTIAN BUSINESS.
- Creator
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Kruger, Dawn, Marinara, Martha, University of Central Florida
- Abstract / Description
-
This paper is an inquiry into the discourse styles of men and women who work together in a conservative Protestant Christian business. Many conservative Protestant Christian churches teach that the Bible forbids women from holding positions of authority over men. Yet in the communications department of this particular business, women fill the top three management positions, supervising a mixed-gender staff of 15. Research has shown that men and women subconsciously use language markers that...
Show moreThis paper is an inquiry into the discourse styles of men and women who work together in a conservative Protestant Christian business. Many conservative Protestant Christian churches teach that the Bible forbids women from holding positions of authority over men. Yet in the communications department of this particular business, women fill the top three management positions, supervising a mixed-gender staff of 15. Research has shown that men and women subconsciously use language markers that indicate personal attitudes toward the same and the opposite genders. This research project draws on that information while it analyzes the oral and electronic discourse of the communications staff. The purpose of this study is to observe whether or not the traditional teachings of conservative Protestant Christian churches has influenced the attitudes of these men and women with regard to women in positions of authority over men in a Christian business. Two staff meetings and a lunchroom conversation were audio taped and transcribed to note oral discourse patterns. One hundred and eleven emails were examined to mark patterns of written discourse. This data was then evaluated against published research in the area of gendered discourse markers. The results indicate that two of the three women in leadership positions over men were comfortable with their positions of authority, but the third woman's discourse patterns showed signs of insecurity. Furthermore, the men in the department did not indicate signs that they seek to exercise power over women, nor did they show signs of difficulty in submitting to the authority of the women. The women staff members, however, showed definite indications of being insecure in a mixed group, and of being meekly subordinate to anyone in authority over them. These results, while helpful, are not definitive in that they do not account for the possibility of other influencing factors, such as personality types, job roles and expectations, age differences, or church teachings on meekness and submission to authority. However, the results of this research indicate that some conservative Christian men are ready for and able to embrace the concept of having women in positions of authority over them, even in a Christian environment, and a few conservative, Christian women are ready to step into those positions. Also from this research it could be concluded that, on the average, conservative women struggle more with the shift of authority than men do. More research would need to be done to address that question fully.
Show less - Date Issued
- 2005
- Identifier
- CFE0000631, ucf:52852
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000631
- Title
- An Integrated Design for Six Sigma-Based Framework To Align Strategy, New Process Development, and Customer Requirements In The Airlines Industry.
- Creator
-
Alghamdi, Mohammed, Elshennawy, Ahmad, Rabelo, Luis, Lee, Gene, Ahmad, Ali, University of Central Florida
- Abstract / Description
-
When organizations create new strategy maps, key new processes are often identified. This is important for organizations to stay competitive in the global marketplace. This document describes the development, implementation, and validation of a framework that properly aligns and links an organization's strategy and new process development. The proposed framework integrates the Balanced Scorecard management system (BSC) and the Design for Six Sigma (DFSS) methodology, leveraging their...
Show moreWhen organizations create new strategy maps, key new processes are often identified. This is important for organizations to stay competitive in the global marketplace. This document describes the development, implementation, and validation of a framework that properly aligns and links an organization's strategy and new process development. The proposed framework integrates the Balanced Scorecard management system (BSC) and the Design for Six Sigma (DFSS) methodology, leveraging their strengths, overcoming weaknesses, and identifying lessons learned to help bridge the gap between strategy development and execution. The critical-to-quality conceptual model is used as an integrative component for the framework. Literature search has resulted in little or no research into the development of similar frameworks. To demonstrate and evaluate the effectiveness of the framework in a real-world environment, a case study is carried out and implemented successfully. As the case study progressed, cycle time as a performance indicator was estimated and showed progression towards the targeted strategic objective. The developed framework helps decision-makers seamlessly transit from a strategic position to process development linking strategic objectives to the critical-to-quality features. This comprehensive framework can help move organizations from where they currently are to where they want to be, laying the background needed for customer satisfaction and breakthrough performance.
Show less - Date Issued
- 2016
- Identifier
- CFE0006246, ucf:51079
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006246
- Title
- An Integrated Framework for Automated Data Collection and Processing for Discrete Event Simulation Models.
- Creator
-
Rodriguez, Carlos, Kincaid, John, Karwowski, Waldemar, O'Neal, Thomas, Kaup, David, Mouloua, Mustapha, University of Central Florida
- Abstract / Description
-
Discrete Events Simulation (DES) is a powerful tool of modeling and analysis used in different disciplines. DES models require data in order to determine the different parameters that drive the simulations. The literature about DES input data management indicates that the preparation of necessary input data is often a highly manual process, which causes inefficiencies, significant time consumption and a negative user experience.The focus of this research investigation is addressing the manual...
Show moreDiscrete Events Simulation (DES) is a powerful tool of modeling and analysis used in different disciplines. DES models require data in order to determine the different parameters that drive the simulations. The literature about DES input data management indicates that the preparation of necessary input data is often a highly manual process, which causes inefficiencies, significant time consumption and a negative user experience.The focus of this research investigation is addressing the manual data collection and processing (MDCAP) problem prevalent in DES projects. This research investigation presents an integrated framework to solve the MDCAP problem by classifying the data needed for DES projects into three generic classes. Such classification permits automating and streamlining the preparation of the data, allowing DES modelers to collect, update, visualize, fit, validate, tally and test data in real-time, by performing intuitive actions. In addition to the proposed theoretical framework, this project introduces an innovative user interface that was programmed based on the ideas of the proposed framework. The interface is called DESI, which stands for Discrete Event Simulation Inputs.The proposed integrated framework to automate DES input data preparation was evaluated against benchmark measures presented in the literature in order to show its positive impact in DES input data management. This research investigation demonstrates that the proposed framework, instantiated by the DESI interface, addresses current gaps in the field, reduces the time devoted to input data management within DES projects and advances the state-of-the-art in DES input data management automation.
Show less - Date Issued
- 2015
- Identifier
- CFE0005878, ucf:50861
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005878
- Title
- An Integrated Hydrodynamic-Marsh Model with Applications in Fluvial, Marine, and Mixed Estuarine Systems.
- Creator
-
Alizad, Karim, Hagen, Scott, Medeiros, Stephen, Wang, Dingbao, Weishampel, John, University of Central Florida
- Abstract / Description
-
Coastal wetlands experience fluctuating productivity when subjected to various stressors. One of the most impactful stressors is sea level rise (SLR) associated with global warming. Research has shown that under SLR, salt marshes may not have time to establish an equilibrium with sea level and may migrate landward or become open water. Salt marsh systems play an important role in the coastal ecosystem by providing intertidal habitats and food for birds, fish, crabs, mussels, and other animals...
Show moreCoastal wetlands experience fluctuating productivity when subjected to various stressors. One of the most impactful stressors is sea level rise (SLR) associated with global warming. Research has shown that under SLR, salt marshes may not have time to establish an equilibrium with sea level and may migrate landward or become open water. Salt marsh systems play an important role in the coastal ecosystem by providing intertidal habitats and food for birds, fish, crabs, mussels, and other animals. They also protect shorelines by dissipating flow and damping wave energy through an increase in drag forces. Due to the serious consequences of losing coastal wetlands, evaluating the potential future changes in their structure and distribution is necessary in order for coastal resource managers to make informed decisions. The objective of this study was to develop a spatially-explicit model by connecting a hydrodynamic model and a parametric marsh model and using it to assess the dynamic effects of SLR on salt marsh systems within three National Estuarine Research Reserves (NERRs) in the Northern Gulf of Mexico. Coastal salt marsh systems are an excellent example of complex interrelations between physics and biology, and the resulting benefits to humanity. In order to investigate salt marsh productivity under projected SLR scenarios, a depth integrated hydrodynamic model was coupled to a parametric marsh model to capture the dynamic feedback loop between physics and biology. The hydrodynamic model calculates mean high water (MHW) and mean low water (MLW) within the river and tidal creeks by harmonic analysis of computed tidal constituents. The responses of MHW and MLW to SLR are nonlinear due to localized changes in the salt marsh platform elevation and biomass productivity (which influences bottom friction). Spatially-varying MHW and MLW are utilized in a two-dimensional application of the parametric Marsh Equilibrium Model to capture the effects of the hydrodynamics on biomass productivity and salt marsh accretion, where accretion rates are dependent on the spatial distribution of sediment deposition in the marsh. This model accounts both organic (decomposition of in-situ biomass) and inorganic (allochthonous) marsh platform accretion and the effects of spatial and temporal biomass density changes on tidal flows. The coupled hydro-marsh model, herein referred to as HYDRO-MEM, leverages an optimized coupling time step at which the two models exchange information and update the solution to capture the system's response to projected linear and non-linear SLR rates.Including accurate marsh table elevations into the model is crucial to obtain meaningful biomass productivity projections. A lidar-derived Digital Elevation Model (DEM) was corrected by incorporating Real Time Kinematic (RTK) surveying elevation data. Additionally, salt marshes continually adapt in an effort to reach an equilibrium within the ideal range of relative SLR and depth of inundation. The inputs to the model, specifically topography and bottom roughness coefficient, are updated using the biomass productivity results at each coupling time step to capture the interaction between the marsh and hydrodynamic models.The coupled model was tested and validated in the Timucuan marsh system, located in northeastern Florida by computing projected biomass productivity and marsh platform elevation under two SLR scenarios. The HYDRO-MEM model coupling protocol was assessed using a sensitivity study of the influence of coupling time step on the biomass productivity results with a comparison to results generated using the MEM approach only. Subsequently, the dynamic effects of SLR were investigated on salt marsh productivity within the three National Estuarine Research Reserves (NERRs) (Apalachicola, FL, Grand Bay, MS, and Weeks Bay, AL) in the Northern Gulf of Mexico (NGOM). These three NERRS are fluvial, marine and mixed estuarine systems, respectively. Each NERR has its own unique characteristics that influence the salt marsh ecosystems. The HYDRO-MEM model was used to assess the effects of four projections of low (0.2 m), intermediate-low (0.5 m), intermediate-high (1.2 m) and high (2.0 m) SLR on salt marsh productivity for the year 2100 for the fluvial dominated Apalachicola estuary, the marine dominated Grand Bay estuary, and the mixed Weeks Bay estuary. The results showed increased productivity under the low SLR scenario and decreased productivity under the intermediate-low, intermediate-high, and high SLR. In the intermediate-high and high SLR scenarios, most of the salt marshes drowned (converted to open water) or migrated to higher topography. These research presented herein advanced the spatial modeling and understanding of dynamic SLR effects on coastal wetland vulnerability. This tool can be used in any estuarine system to project salt marsh productivity and accretion under sea level change scenarios to better predict possible responses to projected SLR scenarios. The findings are not only beneficial to the scientific community, but also are useful to restoration, planning, and monitoring activities in the NERRs. Finally, the research outcomes can help policy makers and coastal managers to choose suitable approaches to meet the specific needs and address the vulnerabilities of these three estuaries, as well as other wetland systems in the NGOM and marsh systems anywhere in the world.
Show less - Date Issued
- 2016
- Identifier
- CFE0006523, ucf:51360
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006523
- Title
- AN INTEGRATED HYDROLOGY/HYDRAULIC AND WATER QUALITY MODEL FOR WATERSHED-SCALE SIMULATIONS.
- Creator
-
Wang, Cheng, Yeh, Gour-Tsyh, University of Central Florida
- Abstract / Description
-
This dissertation presents the design of an integrated watershed model, WASH123D version 3.0, a first principle, physics-based watershed-scale model of integrated hydrology/hydraulics and water quality transport. This numerical model is comprised of three modules: (1) a one-dimensional (1-D) simulation module that is capable of simulating separated and coupled fluid flow, sediment transport and reaction-based water quality transport in river/stream/canal networks and through control...
Show moreThis dissertation presents the design of an integrated watershed model, WASH123D version 3.0, a first principle, physics-based watershed-scale model of integrated hydrology/hydraulics and water quality transport. This numerical model is comprised of three modules: (1) a one-dimensional (1-D) simulation module that is capable of simulating separated and coupled fluid flow, sediment transport and reaction-based water quality transport in river/stream/canal networks and through control structures; (2) a two-dimensional (2-D) simulation module, capable of simulating separated and coupled fluid flow, sediment transport, and reactive biogeochemical transport and transformation in two-dimensional overland flow systems; and (3) a three-dimensional (3-D) simulation module, capable of simulating separated and coupled fluid flow and reactive geochemical transport and transformation in three-dimensional variably saturated subsurface systems. The Saint Venant equation and its simplified versions, diffusion wave and kinematic wave forms, are employed for surface fluid flow simulations and the modified Richards equation is applied for subsurface flow simulation. The reaction-based advection-dispersion equation is used as the governing equation for water quality transport. Several physically and mathematically based numerical options are provided to solve these governing equations for different application purposes. The surface-subsurface water interactions are considered in the flow module and simulated on the basis of continuity of interface. In the transport simulations, fast/equilibrium reactions are decoupled from slow/kinetic reactions by the decomposition of reaction networks; this enables robust numerical integrations of the governing equation. Kinetic variables are adopted as primary dependent variables rather than biogeochemical species to reduce the number of transport equations and simplify the reaction terms. In each time step, hydrologic/hydraulic variables are solved in the flow module; kinetic variables are then solved in the transport module. This is followed by solving the reactive chemical system node by node to yield concentrations of all species. Application examples are presented to demonstrate the design capability of the model. This model may be of interest to environmental scientists, engineers and decision makers as a comprehensive assessment tool to reliably predict the fluid flow as well as sediment and contaminant transport on watershed scales so as to evaluate the efficacy and impact of alternative watershed management and remediation techniques prior to incurring expense in the field.
Show less - Date Issued
- 2009
- Identifier
- CFE0002947, ucf:47955
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002947
- Title
- AN INTEGRATED MODEL OF WORK CLIMATE.
- Creator
-
Kuenzi, Maribeth, Schminke, Marshall, University of Central Florida
- Abstract / Description
-
Management scholars have become increasingly interested in the role of organizational context. As part of this trend, research on work climates has thrived. This contemporary climate research differs from traditional approaches by concentrating on facet-specific climate types like service or innovation, rather than general, global conceptualizations of climate. Consequently, the climate literature has become fragmented and disorderly. I seek to remedy this in my dissertation. Specifically, I...
Show moreManagement scholars have become increasingly interested in the role of organizational context. As part of this trend, research on work climates has thrived. This contemporary climate research differs from traditional approaches by concentrating on facet-specific climate types like service or innovation, rather than general, global conceptualizations of climate. Consequently, the climate literature has become fragmented and disorderly. I seek to remedy this in my dissertation. Specifically, I propose and test an integrated model of work climate that examines both molar and facet-specific climates. Chapter 1 is a review of the organizational work climate literature. This review seeks to review, reorganize, and reintegrate the climate literature. In addition, this review brought to light an issue that hinders the integration of the climate literatures: the literature does not contain a quality instrument for assessing the general characteristics of the molar work climate of an organization. In Chapter 2, I develop a theoretically-driven measure of work climate by drawing on the competing values framework (Quinn & Rohrbaugh, 1983). Preliminary results from three studies suggest that the proposed four-component model of molar work climate appears to be viable. The results indicate the instrument has internal reliability. Further, the results demonstrate discriminant, convergent, and criterion-related validity. In Chapter 3, I propose and test an integrated model of work climate by drawing on bandwidth-fidelity theory (Cronbach & Gleser, 1957). I predict that facet-specific climates will be more strongly related to specific outcomes and molar climates will be more strongly related to global outcomes. Further, I suggest weaker, indirect relationships between molar climate and specific outcomes and between facet-specific climates and global outcomes. The results indicate support for my predictions.
Show less - Date Issued
- 2008
- Identifier
- CFE0002032, ucf:47576
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002032
- Title
- An intelligent editor for natural language processing of unrestricted text.
- Creator
-
Glinos, Demetrios George, Gomez, Fernando, Arts and Sciences
- Abstract / Description
-
University of Central Florida College of Arts and Sciences Thesis; The understanding of natural language by computational methods has been a continuing and elusive problem in artificial intelligence. In recent years there has been a resurgence in natural language processing research. Much of this work has been on empirical or corpus-based methods which use a data-driven approach to train systems on large amounts of real language data. Using corpus-based methods, the performance of part-of...
Show moreUniversity of Central Florida College of Arts and Sciences Thesis; The understanding of natural language by computational methods has been a continuing and elusive problem in artificial intelligence. In recent years there has been a resurgence in natural language processing research. Much of this work has been on empirical or corpus-based methods which use a data-driven approach to train systems on large amounts of real language data. Using corpus-based methods, the performance of part-of-speech (POS) taggers, which assign to the individual words of a sentence their appropriate part of speech category (e.g., noun, verb, preposition), now rivals human performance levels, achieving accuracies exceeding 95%. Such taggers have proved useful as preprocessors for such tasks as parsing, speech synthesis, and information retrieval. Parsing remains, however, a difficult problem, even with the benefit of POS tagging. Moveover, as sentence length increases, there is a corresponding combinatorial explosing of alternative possible parses. Consider the following sentence from a New York Times online article: After Salinas was arrested for murder in 1995 and lawyers for the bank had begun monitoring his accounts, his personal banker in New York quietly advised Salinas' wife to move the money elsewhere, apparently without the consent of the legal department. To facilitate the parsing and other tasks, we would like to decompose this sentence into the following three shorter sentences which, taken together, convey the same meaning as the original: 1. Salinas was arrested for murder in 1995. 2. Lawyers for the bank had begun monitoring his accounts. 3. His personal banker in New York quietly advised Salinas' wife to move the money elsewhere, apparently without the consent of the legal department. This study investigates the development of heuristics for decomposing such long sentences into sets of shorter sentences without affecting the meaning of the original sentences. Without parsing or semantic analysis, heuristic rules were developed based on: (1) the output of a POS tagger (Brill's tagger); (2) the punctuation contained in the input sentences; and (3) the words themselves. The heuristic algorithms were implemented in an intelligent editor program which first augmented the POS tags and assigned tags to punctuation, and then tested the rules against a corpus of 25 New York Times online articles containing approximately 1,200 sentences and over 32,000 words, with good results. Recommendations are made for improving the algorithms and for continuing this line of research.
Show less - Date Issued
- 1999
- Identifier
- CFR0008181, ucf:53055
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0008181
- Title
- AN INTERACTIVE DISTRIBUTED SIMULATION FRAMEWORK WITH APPLICATION TO WIRELESS NETWORKS AND INTRUSION DETECTION.
- Creator
-
Kachirski, Oleg, Guha, Ratan, University of Central Florida
- Abstract / Description
-
In this dissertation, we describe the portable, open-source distributed simulation framework (WINDS) targeting simulations of wireless network infrastructures that we have developed. We present the simulation framework which uses modular architecture and apply the framework to studies of mobility pattern effects, routing and intrusion detection mechanisms in simulations of large-scale wireless ad hoc, infrastructure, and totally mobile networks. The distributed simulations within the...
Show moreIn this dissertation, we describe the portable, open-source distributed simulation framework (WINDS) targeting simulations of wireless network infrastructures that we have developed. We present the simulation framework which uses modular architecture and apply the framework to studies of mobility pattern effects, routing and intrusion detection mechanisms in simulations of large-scale wireless ad hoc, infrastructure, and totally mobile networks. The distributed simulations within the framework execute seamlessly and transparently to the user on a symmetric multiprocessor cluster computer or a network of computers with no modifications to the code or user objects. A visual graphical interface precisely depicts simulation object states and interactions throughout the simulation execution, giving the user full control over the simulation in real time. The network configuration is detected by the framework, and communication latency is taken into consideration when dynamically adjusting the simulation clock, allowing the simulation to run on a heterogeneous computing system. The simulation framework is easily extensible to multi-cluster systems and computing grids. An entire simulation system can be constructed in a short time, utilizing user-created and supplied simulation components, including mobile nodes, base stations, routing algorithms, traffic patterns and other objects. These objects are automatically compiled and loaded by the simulation system, and are available for dynamic simulation injection at runtime. Using our distributed simulation framework, we have studied modern intrusion detection systems (IDS) and assessed applicability of existing intrusion detection techniques to wireless networks. We have developed a mobile agent-based IDS targeting mobile wireless networks, and introduced load-balancing optimizations aimed at limited-resource systems to improve intrusion detection performance. Packet-based monitoring agents of our IDS employ a CASE-based reasoner engine that performs fast lookups of network packets in the existing SNORT-based intrusion rule-set. Experiments were performed using the intrusion data from MIT Lincoln Laboratories studies, and executed on a cluster computer utilizing our distributed simulation system.
Show less - Date Issued
- 2005
- Identifier
- CFE0000642, ucf:46545
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000642
- Title
- AN INTERACTIVE FRAMEWORK FOR MESHLESS METHODS ANALYSIS IN COMPUTATIONAL MECHANICS AND THERMOFLUIDS.
- Creator
-
Gerace, Salvadore, Kassab, Alain, University of Central Florida
- Abstract / Description
-
In recent history, the area of physics-based engineering simulation has seen rapid increases in both computer workstation performance as well as common model complexity, both driven largely in part by advances in memory density and availability of clusters and multi-core processors. While the increase in computation time due to model complexity has been largely offset by the increased performance of modern workstations, the increase in model setup time due to model complexity has continued to...
Show moreIn recent history, the area of physics-based engineering simulation has seen rapid increases in both computer workstation performance as well as common model complexity, both driven largely in part by advances in memory density and availability of clusters and multi-core processors. While the increase in computation time due to model complexity has been largely offset by the increased performance of modern workstations, the increase in model setup time due to model complexity has continued to rise. As such, the major time requirement for solving an engineering model has transitioned from computation time to problem setup time. This is due to the fact that developing the required mesh for complex geometry can be an extremely complicated and time consuming task. Consequently, new solution techniques which are capable of reducing the required amount of human interaction are desirable. The subject of this thesis is the development of a novel meshless method that promises to eliminate the need for structured meshes, and thus, the need for complicated meshing procedures. Although the savings gain due to eliminating the meshing process would be more than sufficient to warrant further study, the proposed method is also capable of reducing the computation time and memory footprint compared to similar models solved using more traditional finite element, finite difference, finite volume, or boundary element methods. In particular, this thesis will outline the development of an interactive, meshless, physically accurate modeling environment that provides an extensible framework which can be applied to a multitude of governing equations encountered in computational mechanics and thermofluids. Additionally, through the development of tailored preprocessing routines, efficiency and accuracy of the proposed meshless algorithms can be tested in a more realistic and flexible environment. Examples are provided in the areas of elasticity, heat transfer and computational fluid dynamics.
Show less - Date Issued
- 2007
- Identifier
- CFE0001913, ucf:47484
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001913
- Title
- AN INTERSECTIONAL COMPARISON OF FEMALE AGENCY IN TONI MORRISON'S SULA AND WANG ANYI'S SONG OF EVERLASTING SORROW.
- Creator
-
Lynton, Jordan, Bell, Kathleen, University of Central Florida
- Abstract / Description
-
The opportunities created by the end of the Mao Era and legislature promoting the rights of African Americans and women in the mid-twentieth century allowed women of both cultures to break further into the literary scene and negotiate their own sense of agency through their work. Although Western feminism also grew rapidly throughout this period, its ethnocentric centering of gender prevented it from being a reliable lens with which to analyze the work of Chinese and African American women...
Show moreThe opportunities created by the end of the Mao Era and legislature promoting the rights of African Americans and women in the mid-twentieth century allowed women of both cultures to break further into the literary scene and negotiate their own sense of agency through their work. Although Western feminism also grew rapidly throughout this period, its ethnocentric centering of gender prevented it from being a reliable lens with which to analyze the work of Chinese and African American women who experienced issues of race, class, and gender simultaneously. This caused Western feminists to evaluate the work of Chinese and African American women from a perspective of privilege and misrepresented the cultural, social, and political influences that impacted their agency. Thus, this paper seeks to evaluate the effectiveness of the intersectional paradigm as a comparative lens with which to analyze the construction of female characters in mid-twentieth century Chinese and African American fiction in place of a Western feminist lens. To this effect, it will apply the intersectional lens to Toni Morrison's Sula (1973) and Wang Anyi's Song of Everlasting Sorrow (2008) specifically, to determine how this research paradigm can be used to reveal the identities the female protagonists construct and their opportunities for agency. This paper hopes to increase discourse on the applications of intersectionality in literature as a tool for better understanding the literature of women of color.
Show less - Date Issued
- 2013
- Identifier
- CFH0004436, ucf:45124
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004436
- Title
- AN INTERVAL BASED APPROACH TO MODEL INPUT UNCERTAINTY IN DISCRETE-EVENT SIMULATION.
- Creator
-
Batarseh, Ola, Wang, Yan, University of Central Florida
- Abstract / Description
-
The objective of this research is to increase the robustness of discrete-event simulation (DES) when input uncertainties associated models and parameters are present. Input uncertainties in simulation have different sources, including lack of data, conflicting information and beliefs, lack of introspection, measurement errors, and lack of information about dependency. A reliable solution is obtained from a simulation mechanism that accounts for these uncertainty components in simulation. An...
Show moreThe objective of this research is to increase the robustness of discrete-event simulation (DES) when input uncertainties associated models and parameters are present. Input uncertainties in simulation have different sources, including lack of data, conflicting information and beliefs, lack of introspection, measurement errors, and lack of information about dependency. A reliable solution is obtained from a simulation mechanism that accounts for these uncertainty components in simulation. An interval-based simulation (IBS) mechanism based on imprecise probabilities is proposed, where the statistical distribution parameters in simulation are intervals instead of precise real numbers. This approach incorporates variability and uncertainty in systems. In this research, a standard procedure to estimate interval parameters of probability distributions is developed based on the measurement of simulation robustness. New mechanisms based on the inverse transform to generate interval random variates are proposed. A generic approach to specify the required replication length to achieve a desired level of robustness is derived. Furthermore, three simulation clock advancement approaches in the interval-based simulation are investigated. A library of Java-based IBS toolkits that simulates queueing systems is developed to demonstrate the new proposed reliable simulation. New interval statistics for interval data analysis are proposed to support decision making. To assess the performance of the IBS, we developed an interval-based metamodel for automated material handling systems, which generates interval performance measures that are more reliable and computationally more efficient than traditional DES simulation results.
Show less - Date Issued
- 2010
- Identifier
- CFE0003343, ucf:48441
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003343
- Title
- AN INTRODUCTION TO HELLMANN-FEYNMAN THEORY.
- Creator
-
Wallace, David, Ismail, Mourad, University of Central Florida
- Abstract / Description
-
The Hellmann-Feynman theorem is presented together with certain allied theorems. The origin of the Hellmann-Feynman theorem in quantum physical chemistry is described. The theorem is stated with proof and with discussion of applicability and reliability. Some adaptations of the theorem to the study of the variation of zeros of special functions and orthogonal polynomials are surveyed. Possible extensions are discussed.
- Date Issued
- 2005
- Identifier
- CFE0000403, ucf:46349
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000403
- Title
- An Introductory Study of The Dynamics of Autorotation for Wind Energy Harvesting.
- Creator
-
Salih, Bilal, Das, Tuhin, Kassab, Alain, Kauffman, Jeffrey, University of Central Florida
- Abstract / Description
-
Wind turbines have been used for decades to harvest wind energy. They are suitable only to work on close to ground, and have several drawbacks that are related to the availability of the wind and the amount of extracted power compared with the cost of construction. On the other hand, there is an abundant wind power that is available at high altitudes. The wind jet streams at high elevations 8 ? 12 kms are pervasive and persistent, and can potentially produce immense wind energy. Even at...
Show moreWind turbines have been used for decades to harvest wind energy. They are suitable only to work on close to ground, and have several drawbacks that are related to the availability of the wind and the amount of extracted power compared with the cost of construction. On the other hand, there is an abundant wind power that is available at high altitudes. The wind jet streams at high elevations 8 ? 12 kms are pervasive and persistent, and can potentially produce immense wind energy. Even at moderate elevations of 4 ? 5 kms, wind power densities are much higher than on ground and more consistent. Consequently, in this thesis research, we investigate the topic of harvesting energy from high altitudes. First, we provide a comprehensive review of two existing theoretical methods that are proposed for airborne wind energy harvesting, the tethered airfoil, and the static autogyro. The latter approach has inherent advantages that warrant further investigation. Autorotation is a well-known phenomenon where a rotor sustains its angular velocity and maintains significant lift in the presence of strong aerodynamic forces and torques generated by interaction with a strong wind field. Autorotation has been researched in the context of free descent of helicopters but has not been considered for energy harvesting. Existing models have mainly focused on statics analysis. In this research, we propose a simple dynamic model of the Autogyro, with the goal of ultimately realizing an Autorotation Energy System (AES). The focus of our work is to provide a preliminary dynamic analysis of autorotation, which is largely absent in current literature, to explore the possibility of using autorotation for designing a multipurpose system that can simultaneously fly at high altitudes and generate energy from the wind. The proposed preliminary dynamic model is used to generate a simulation platform, which is used to explore the autogyros rudimentary maneuvers. Extensive simulation results are provided to evaluate the dynamic performance of AES. Energy harvesting analyses and results are also presented. It is expected that the results will guide the choice of actuations and control that will be necessary for generating combined autorotation and powered flights that would be net energy generating or energy efficient. The research will be relevant for both tethered and untethered AES and could also be incorporated into multi-rotor based UAVs such as quadrotors.
Show less - Date Issued
- 2014
- Identifier
- CFE0005245, ucf:50597
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005245
