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- Title
- DIALOGIC READING WITH ADOLESCENT MOTHERS.
- Creator
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Abarca, Diana L, Towson, Jacqueline, University of Central Florida
- Abstract / Description
-
The purpose of this study was to evaluate the effectiveness of teaching dialogic reading (DR) strategies to adolescent mothers as measured by DR strategy use during shared book reading with their children. The secondary purpose was to determine the impact of adolescent mothers' implementation of DR strategies on their preschool children's single word vocabulary. A single subject multiple baseline across behaviors research design was implemented with one adolescent mother and her twin boys....
Show moreThe purpose of this study was to evaluate the effectiveness of teaching dialogic reading (DR) strategies to adolescent mothers as measured by DR strategy use during shared book reading with their children. The secondary purpose was to determine the impact of adolescent mothers' implementation of DR strategies on their preschool children's single word vocabulary. A single subject multiple baseline across behaviors research design was implemented with one adolescent mother and her twin boys. Based on visual analysis of graphical representation of the data, it was determined there was a moderate to strong functional relation between educating an adolescent mother on DR and her implementation of DR strategies during shared book reading, depending on the DR strategy. Receptive and expressive scores on the individual book assessments decreased from baseline to intervention. These results provide preliminary evidence that adolescent mothers have the potential to implement new strategies during shared book reading when provided with direct support. Future research with this population should strive towards developing an intervention for adolescent mothers and their children to enhance children's language and literacy development.
Show less - Date Issued
- 2018
- Identifier
- CFH2000277, ucf:45821
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000277
- Title
- A Multiple Case Study Exploring the Relationship Between Engagement in Model-Eliciting Activities and Pre-Service Secondary Mathematics Teachers' Mathematical Knowledge for Teaching Algebra.
- Creator
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Abassian, Aline, Safi, Farshid, Dixon, Juli, Andreasen, Janet, Bush, Sarah, Bostic, Jonathan, University of Central Florida
- Abstract / Description
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The goal of this research study was to explore the nature of the relationship between engagement in model-eliciting activities (MEAs) and pre-service secondary mathematics teachers' (PSMTs') mathematical knowledge for teaching (MKT) algebra. The data collection took place in an undergraduate mathematics education content course for secondary mathematics education majors. In this multiple case study, PSMTs were given a Learning Mathematics for Teaching (LMT) pre-assessment designed to measure...
Show moreThe goal of this research study was to explore the nature of the relationship between engagement in model-eliciting activities (MEAs) and pre-service secondary mathematics teachers' (PSMTs') mathematical knowledge for teaching (MKT) algebra. The data collection took place in an undergraduate mathematics education content course for secondary mathematics education majors. In this multiple case study, PSMTs were given a Learning Mathematics for Teaching (LMT) pre-assessment designed to measure their MKT algebra, and based on those results, three participants were selected with varying levels of knowledge. This was done to ensure varied cases were represented in order to be able to examine and describe multiple perspectives. The three examined cases were Oriana, a PSMT with high MKT, Bianca, a PSMT with medium MKT, and Helaine, a PSMT with low MKT. Over the course of five weeks, the three PSMTs were recorded exploring three MEAs, participated in two interviews, and submitted written reflections. The extensive amount of data collected in this study allowed the researcher to deeply explore the PSMTs' MKT algebra in relation to the given MEAs, with a focus on three specific constructs(-)bridging, trimming, and decompressing(-) based on the Knowledge of Algebra for Teaching (KAT) framework. The results of this study suggest that engaging in MEAs could elicit PSMTs' MKT algebra, and in some cases such tasks were beneficial to their trimming, bridging, and decompressing abilities. Exploring MEAs immersed the PSMTs in generating descriptions, explanations, and constructions, that helped reveal how they interpreted mathematical situations that they encountered. The tasks served as useful tools for PSMTs to have deep discussions and productive discourse on various algebra topics, and make many different mathematical connections in the process.
Show less - Date Issued
- 2018
- Identifier
- CFE0007143, ucf:52305
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007143
- Title
- A Framework for Measuring and Analyzing Customer Satisfaction at Computer Service Company using Lean Six Sigma.
- Creator
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Abboodi, Mohammed, Elshennawy, Ahmad, Rabelo, Luis, Xanthopoulos, Petros, University of Central Florida
- Abstract / Description
-
The computer service industry has been expanding dramatically due to the increase in the number of computing machineries in the last two decades. The entrance of large size companies in the market and the release of online tools that have the ability for diagnosing and troubleshooting hardware and software issues have boosted the competition. In the meantime, many of the small and medium size companies find themselves unable to keep their customers satisfied since their competitors provide...
Show moreThe computer service industry has been expanding dramatically due to the increase in the number of computing machineries in the last two decades. The entrance of large size companies in the market and the release of online tools that have the ability for diagnosing and troubleshooting hardware and software issues have boosted the competition. In the meantime, many of the small and medium size companies find themselves unable to keep their customers satisfied since their competitors provide high quality service with lower cost. The lack of a good measurement system to assess and analyze the satisfaction level with the provided service is the fundamental cause of customer decline. The aim of this study is to construct a robust framework to measure customer satisfaction and highlight the root causes of dissatisfaction in the computer service sector. This framework brings together the key aspects of Six Sigma and SERVQUAL instruments into a structured approach to measure and analyze customer satisfaction with computer services. It deploys the DMAIC problem solving methodology along with the SERVQUAL model, which contributes service dimensions and the Gap Analyze technique. Literature review indicates there have not been enough studies conducted to integrate Lean Six Sigma with SERVQUAL. To explore the effectiveness of the current framework, a computer service company has been selected. The satisfaction levels are calculated and the root causes of dissatisfaction have been identified. With a low overall customer satisfaction level, the company did not fulfill their customer requirements due to five major causes. Eliminating those causes will boost customer satisfaction, reduce the cost of acquiring new customers and improve the company performance in general.
Show less - Date Issued
- 2014
- Identifier
- CFE0005117, ucf:50751
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005117
- Title
- Ferdinand de Soto: the discoverer of the Mississippi.
- Creator
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Abbott, John S. C. (John Stevens Cabot), PALMM (Project)
- Abstract / Description
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A history of the expeditions and military conquests of Hernando de Soto in South America, Florida, Georgia, and Alabama.
- Date Issued
- 1873
- Identifier
- AAA3226QF00011/15/200108/04/200515837BfamI D0QF, 0392343, FHP C CF 2001-11-15, FCLA url 20020220xOCLC, 49296621, CF00001555, 2555781, ucf:6180
- Format
- E-book
- PURL
- http://purl.flvc.org/fcla/dl/CF00001555.jpg
- Title
- USING GEOGRAPHIC INFORMATION SYSTEMS (GIS) IN SPATIAL ANALYSIS OF MORTUARY PRACTICES IN THE KELLIS 2 CEMETERY, DAKHLEH OASIS, EGYPT.
- Creator
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Abd Elsalam, Heba, Dupras, Tosha, University of Central Florida
- Abstract / Description
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This thesis focuses on the use of geographic information systems (GIS) to examine mortuary practices in the Romano-Byzantine period Kellis 2 cemetery located in the Dakhleh Oasis, Egypt. The first research objective examines the relationship between age, sex and grave substructures of 701 burials in Kellis 2 cemetery. The aim of this research objective was to determine if the presence and style of grave substructures were influenced by sex or age. Although not statistically significant, GIS...
Show moreThis thesis focuses on the use of geographic information systems (GIS) to examine mortuary practices in the Romano-Byzantine period Kellis 2 cemetery located in the Dakhleh Oasis, Egypt. The first research objective examines the relationship between age, sex and grave substructures of 701 burials in Kellis 2 cemetery. The aim of this research objective was to determine if the presence and style of grave substructures were influenced by sex or age. Although not statistically significant, GIS analysis revealed that most of the graves in the Kellis 2 cemetery have no associated substructures, but of those that did have associated substructures,adult male burials were more likely to have a substructure than adult females or juveniles. Moreover, males and females aged from 22 to 50 years were more likely to have an associated substructure than younger and older individuals. In the juvenile age categories, newborns and children aged 1 to 5 years were more likely to have an associated substructure than the other juvenile age categories. This may be related to the second research objective which focused on the spatial relationship between infant and adult burials in the Kellis 2 cemetery. The second objective was to determine if infants were more likely to be buried between two adults, perhaps representing family units. GIS and statistical analysis revealed that the infants in the Kellis 2 cemetery were more likely to be buried closer to each other or to adult females than to adult males. Of those 25 infants buried between two adults most of them were either buried between two adult females, or between an adult male and female. Only three infants were found buried between two males. Interestingly, many of the adult females buried in close proximity with an infant were of child-bearing age. GIS was a very useful tool for examining questions of mortuary practices, particularly in examining spatial relationships between variables recorded for the Kellis 2 cemetery.
Show less - Date Issued
- 2011
- Identifier
- CFE0004082, ucf:49134
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004082
- Title
- Computing a diameter-constrained minimum spanning tree.
- Creator
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Abdalla, Ayman Mahmoud, Deo, Narsingh, Engineering and Computer Science
- Abstract / Description
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University of Central Florida College of Engineering Thesis; In numerous practical applications, it is necessary to find the smallest possible tree with a bounded diameter. A diameter-constrained minimum spanning tree (DCMST) of a given undirected, edge-weighted graph, G, is the smallest-weight spanning tree of all spanning trees of G which contain no path with more than k edges, where k is a given positive integer. The problem of finding a DCMST is NP-complete for all values of k; 4
Show moreUniversity of Central Florida College of Engineering Thesis; In numerous practical applications, it is necessary to find the smallest possible tree with a bounded diameter. A diameter-constrained minimum spanning tree (DCMST) of a given undirected, edge-weighted graph, G, is the smallest-weight spanning tree of all spanning trees of G which contain no path with more than k edges, where k is a given positive integer. The problem of finding a DCMST is NP-complete for all values of k; 4 <= k <= (n - 2), except when all edge-weights are identical. A DCMST is essential for the efficiency of various distributed mutual exclusion algorithms, where it can minimize the number of messages communicated among processors per critical section. It is also useful in linear lightwave networks, where it can minimize interference in the network by limiting the traffic in the network lines. Another practical application requiring a DCMST arises in data compression, where some algorithms compress a file utilizing a data-structure, and decompress a path in the tree to access a record A DCMST helps such algorithm to be fast without sacrificing a lot of storage storage space.
Show less - Date Issued
- 2001
- Identifier
- CFR0002215, ucf:52914
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0002215
- Title
- Setting The Agenda For STEM Literacy In Higher Education: A Content Analysis Of The Chronicle Of Higher Education.
- Creator
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Abdallah, Maya, Cintron Delgado, Rosa, Owens, J. Thomas, Welch, Kerry, Batarseh, Issa, University of Central Florida
- Abstract / Description
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Enhancing achievement in Science, Technology, Engineering, and Mathematics (STEM) is a long-standing national concern. The current national agenda, to instill an (")all hands on deck(") approach to creating a STEM literate citizenry, calls for broadening the scope of inclusion in STEM efforts. A critical population, higher education administrators, faculty, and staff are a valuable resource to advancing this agenda. Under the proposed Agenda Setting Communication Theory (ASCT) model developed...
Show moreEnhancing achievement in Science, Technology, Engineering, and Mathematics (STEM) is a long-standing national concern. The current national agenda, to instill an (")all hands on deck(") approach to creating a STEM literate citizenry, calls for broadening the scope of inclusion in STEM efforts. A critical population, higher education administrators, faculty, and staff are a valuable resource to advancing this agenda. Under the proposed Agenda Setting Communication Theory (ASCT) model developed for this study, their level of exposure to needed information is an important indicator of their potential participation in this agenda. As the leading news medium for the higher education community, the Chronicle of Higher Education was examined, through Content Analysis, to identify the frequency of reporting on STEM education from January 2001 to December 2015, to discern the themes in STEM education which appear in the Chronicle of Higher Education from January 2001 to December 2015, and to determine the frequency of reporting on the need for collaboration in STEM education in the Chronicle of Higher Education during that same period. The results of the Content Analysis indicate that there has been a significant increase in the Chronicle's reporting on STEM education in the past five years. Also, matters relating to the recruitment and retention of underrepresented populations were reported on most frequently. Further, reporting on the need for collaboration did not emerge as a primary theme. These results indicate that while the Chronicle is somewhat participating in reflecting aspects of the national STEM education agenda, it is not yet functioning to advance the breadth of that agenda within the higher education community.
Show less - Date Issued
- 2016
- Identifier
- CFE0006239, ucf:51063
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006239
- Title
- ANTENNA-COUPLED TUNNEL DIODES FOR DUAL-BAND MILLIMETER-WAVE/INFRARED FOCAL-PLANE ARRAYS.
- Creator
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Abdel Rahman, Mohamed, Boreman, Glenn, University of Central Florida
- Abstract / Description
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The infrared and millimeter-wave portions of the spectrum both have their advantages for development of imaging systems. Because of the difference in wavelengths, infrared imagers offer inherently high resolution, while millimeter-wave systems have better penetration through atmospheric aerosols such as fog and smoke. Shared-aperture imaging systems employing a common focal-plane array that responds to both wavebands are desirable from the viewpoint of overall size and weight. We have...
Show moreThe infrared and millimeter-wave portions of the spectrum both have their advantages for development of imaging systems. Because of the difference in wavelengths, infrared imagers offer inherently high resolution, while millimeter-wave systems have better penetration through atmospheric aerosols such as fog and smoke. Shared-aperture imaging systems employing a common focal-plane array that responds to both wavebands are desirable from the viewpoint of overall size and weight. We have developed antenna-coupled sensors that respond simultaneously at 30 THz and at 94 GHz, utilizing electron-beam lithography. Slot-antenna designs were found to be particularly suitable for coupling radiation into metal-oxide-metal (MOM) tunnel diodes at both frequencies. The MOM diodes are fabricated in a layered structure of Ni-NiO-Ni, and act as rectifying contacts. With contact areas as low as 120 nm × 120 nm, these diodes have time constants commensurate with rectification at frequencies across the desired millimeter-wave and infrared bands. One challenge in the development of true focal-plane array imagers across this factor-of-300 bandwidth is that the optimum spatial sampling interval on the focal plane is different in both bands. We have demonstrated a focal plane with interleaved infrared and millimeter-wave sensors by fabricating infrared antennas in the ground plane of the millimeter-wave antenna. Measured performance data in both bands are presented for individual antenna-coupled sensors as well as for devices in the dual-band focal-plane-array format.
Show less - Date Issued
- 2004
- Identifier
- CFE0000305, ucf:46309
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000305
- Title
- INFRARED THERMOGRAPHY AND HIGH ACCURACY GPS FOR AUTOMATED ASPHALT CRACK DETECTION.
- Creator
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Abdel-Monem, Tarek, Oloufa, Amr, University of Central Florida
- Abstract / Description
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Roads are major public assets. The USA spends billions of dollars each year on road construction and maintenance. To keep these roads in a healthy condition and for better planning and allocation of maintenance budgets, knowledge of distressed locations is needed. Roads develop cracks when they are subjected to stresses that exceed their designed criteria or their materials properties. Early detection and repair of cracks has proven to be the most cost-effective strategy in limiting the...
Show moreRoads are major public assets. The USA spends billions of dollars each year on road construction and maintenance. To keep these roads in a healthy condition and for better planning and allocation of maintenance budgets, knowledge of distressed locations is needed. Roads develop cracks when they are subjected to stresses that exceed their designed criteria or their materials properties. Early detection and repair of cracks has proven to be the most cost-effective strategy in limiting the damage to roads and reducing expenditures. Various methodologies of crack detection were developed and significant techniques were made in the last few years. One of the most important recent technologies is the infrared thermography, which allows the use of infrared waves for crack detection. Another important technology is the global navigation satellite system (GNSS) which currently includes the GPS and GLONASS constellations. With the help of these systems, accurate location coordinates (longitude, latitude and altitude) up to a few centimeters were located. The objective of this research is to test the combined use of GNSS and infrared thermography in an automated system for the detection of asphalt cracks and their locations. To achieve this goal, two tests have been conducted. The first one, regarding the location tagging, was done using two pairs of GPS receivers which can detect signals from both GPS and GLONASS navigation systems in single and dual frequencies (L1 and L2). Different modes have been set to the receiver and comparison graphs were developed to compare accuracies against modes. The second test involves an infrared camera mounted on a car and moving in speeds approaching highway speed limit. The images obtained from the camera were processed using cracks detection software to analyze cracks properties (length, width, density and severity). It was found that the images that were taken by a moving infrared camera were recognized by crack detection software for moving speeds up to 50 mph. At speeds higher than 50 mph, images were blurred. As for location test, The GLONASS combined by GPS receivers got slightly better results than GPS only in both dual and single frequencies. The GLONASS satellites are not always available in view and when they are there, the number of satellites that can be detected by receiver range from one to three satellites at the most and for only a short period of time. It is recommended that future research be conducted to investigate the effect of using different camera lenses on the clarity of the images obtained as well as the effect of raising the camera level above the pavement surface in such a way that the whole lane width (12 ft.) would be covered in one image. Also the total reliance on GPS only receivers in determining cracks location has proven to be enough for this application.
Show less - Date Issued
- 2005
- Identifier
- CFE0000668, ucf:46534
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000668
- Title
- ELECTIMIZE: A NEW EVOLUTIONARY ALGORITHM FOR OPTIMIZATION WITH APPLICATIONS IN CONSTRUCTION ENGINEERING.
- Creator
-
Abdel-Raheem, Mohamed, Khalafallah, Ahmed, University of Central Florida
- Abstract / Description
-
Optimization is considered an essential step in reinforcing the efficiency of performance and economic feasibility of construction projects. In the past few decades, evolutionary algorithms (EAs) have been widely utilized to solve various types of construction-related optimization problems due to their efficiency in finding good solutions in relatively short time periods. However, in many cases, these existing evolutionary algorithms failed to identify the optimal solution to several...
Show moreOptimization is considered an essential step in reinforcing the efficiency of performance and economic feasibility of construction projects. In the past few decades, evolutionary algorithms (EAs) have been widely utilized to solve various types of construction-related optimization problems due to their efficiency in finding good solutions in relatively short time periods. However, in many cases, these existing evolutionary algorithms failed to identify the optimal solution to several optimization problems. As such, it is deemed necessary to develop new approaches in order to help identify better-quality solutions. This doctoral research presents the development of a new evolutionary algorithm, named "Electimize," that is based on the simulation of the flow of electric current in the branches of an electric circuit. The main motive in this research is to provide the construction industry with a robust optimization tool that overcomes some of the shortcomings of existing EAs. In solving optimization problems using Electimize, a number of wires (solution strings) composed of a number of segments are fabricated randomly. Each segment corresponds to a decision variable in the objective function. The wires are virtually connected in parallel to a source of an electricity to represent an electric circuit. The electric current passing through each wire is calculated by substituting the values of the segments in the objective function. The quality of the wire is based on its global resistance, which is calculated using Ohm's law. The main objectives of this research are to 1) develop an optimization methodology that is capable of evaluating the quality of decision variable values in the solution string independently; 2) devise internal optimization mechanisms that would enable the algorithm to extensively search the solution space and avoid its convergence toward local optima; and 3) provide the construction industry with a reliable optimization tool that is capable of solving different classes of NP-hard optimization problems. First, internal processes are designed, modeled, and tested to enable the individual assessment of the quality of each decision variable value available in the solution space. The main principle in assessing the quality of each decision variable value individually is to use the segment resistance (local resistance) as an indicator of the quality. This is accomplished by conducting a sensitivity analysis to record the change in the resistance of a control wire, when a certain decision variable value is substituted into the corresponding segment of the control wire. The calculated local resistances of all segments of a wire are then normalized to ensure that their summation is equal to the global wire resistance and no violation is made of Kirchhoff's rule. A benchmark NP-hard cash flow management problem from the literature is attempted to test and validate the performance of the developed approach. Not only was Electimize able to identify the optimal solution for the problem, but also it identified ten alternative optimal solutions, outperforming the existing algorithms. Second, the internal processes for the sensitivity analysis are designed to allow for extensive search of the solution space through the generation of new wires. Every time a decision variable value is substituted in the control wire to assess its quality, a new wire that might have a better quality is generated. To further test the capabilities of Electimize in searching the solution space, Electimize was applied to a multimodal 9-city travelling salesman problem (TSP) that had been previously designed and solved mathematically. The problem has 27 alternative optimal solutions. Electimize succeeded to identify 21 of the 27 alternative optimal solutions in a limited time period. Moreover, Electimize was applied to a 16-city benchmark TSP (Ulysses16) and was able to identify the optimal tour and its alternative. Further, additional parameters are incorporated to 1) allow for the extensive search of the solution space, 2) prevent the convergence towards local optima, and 3) increase the rate of convergence towards the global optima. These parameters are classified into two categories: 1) resistance related parameters, and 2) solution exploration parameters. The resistance related parameters are: a) the conductor resistivity, b) its cross-sectional area, and c) the length of each segment. The main role of this set of parameters is to provide the algorithm with additional gauging parameters to help guide it towards the global optima. The solution exploration parameters included a) the heat factor, and b) the criterion of selecting the control wire. The main role of this set of parameters is to allow for an extensive search of the solution space in order to facilitate the identification all the available alternative optimal solutions; prevent the premature convergence towards local optima; and increase the rate of convergence towards the global optima. Two TSP instances (Bayg29 and ATT48) are attempted and the results obtained illustrate that Electimize outperforms other EAs with respect to the quality of solutions obtained. Third, to test the capabilities of Electimize as a reliable optimization tool in construction optimization problems, three benchmark NP-hard construction optimization problems are attempted. The first problem is the cash flow management problem, as mentioned earlier. The second problem is the time cost tradeoff problem (TCTP) and is used as an example of static optimization. The third problem is a site layout planning problem (SLPP), and represents dynamic optimization. When Electimize was applied to the TCTP, it succeeded to identify the optimal solution of the problem in a single iteration using thirty solution strings, compared to hundreds of iterations and solution strings that were used by EAs to solve the same problem. Electimize was also successful in solving the SLPP and outperformed the existing algorithm used to solve the problem by identifying a better optimal solution. The main contributions of this research are 1) developing a new approach and algorithm for optimization based on the simulation of the phenomenon of electrical conduction, 2) devising processes that enable assessing the quality of decision variable values independently, 3) formulating methodologies that allow for the extensive search of the solution space and identification of alternative optimal solutions, and 4) providing a robust optimization tool for decision makers and construction planners.
Show less - Date Issued
- 2011
- Identifier
- CFE0003954, ucf:48698
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003954
- Title
- ENTIRE LOAD EFFICIENCY AND DYNAMIC PERFORMANCE IMPROVEMENTS FOR DC-DC CONVERTERS.
- Creator
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Abdel-Rahman, Osama, Batarseh, Issa, University of Central Florida
- Abstract / Description
-
The scope of this work can be summarized by three main aspects of DC-DC power converters. The first aspect is soft switching topologies to improve conversion efficiency for On-Board Converters or Point of load (POL) converters, the second aspect is load adaptive control techniques to improve all load efficiency for battery powered DC-DC converters that are applied to mobile devices, and the third aspect is dynamic performance improvement techniques to improve load transient in voltage...
Show moreThe scope of this work can be summarized by three main aspects of DC-DC power converters. The first aspect is soft switching topologies to improve conversion efficiency for On-Board Converters or Point of load (POL) converters, the second aspect is load adaptive control techniques to improve all load efficiency for battery powered DC-DC converters that are applied to mobile devices, and the third aspect is dynamic performance improvement techniques to improve load transient in voltage regulators. Topologies and control techniques for DC-DC converters are presented after reviewing loads powering requirements and steady-state and transients design challenges.
Show less - Date Issued
- 2007
- Identifier
- CFE0001625, ucf:47186
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001625
- Title
- Investigating Social Capital and Political Action in the Middle East.
- Creator
-
Abdel-Wahab, Amr, Morales, Waltraud, Fine, Terri, Houghton, David, University of Central Florida
- Abstract / Description
-
This study addresses the relationship between social capital and political action in the Middle East. The research uncovers indicators of how social capital correlates with democratic action. Using data from the 2005 World Values Survey, the examination centers on indicators of trust and membership in civic organizations and how they relate to political action in the region. The paper concludes with discussion of how trust-building and reciprocity can be interpreted within the political...
Show moreThis study addresses the relationship between social capital and political action in the Middle East. The research uncovers indicators of how social capital correlates with democratic action. Using data from the 2005 World Values Survey, the examination centers on indicators of trust and membership in civic organizations and how they relate to political action in the region. The paper concludes with discussion of how trust-building and reciprocity can be interpreted within the political context of the Middle East, and how the relevance of social capital will be an unavoidable consideration in the transition away from autocracy in the region, especially when considering recent events.
Show less - Date Issued
- 2011
- Identifier
- CFE0004083, ucf:49137
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004083
- Title
- Experimental and numerical investigation of a novel adsorption bed design for cooling applications.
- Creator
-
Abdelhady, Ramy, Chow, Louis, Mansy, Hansen, Das, Tuhin, Duranceau, Steven, University of Central Florida
- Abstract / Description
-
A global challenge is to develop environmentally friendly, affordable, compact and sustainable technologies to provide heating and cooling power. Adsorption cooling (AC) technology is one of the most promising ways to solve the environmental issues and cut down the energy consumption related to the traditional air conditioning and refrigeration systems. However, AC systems still suffer from poor heat and mass transfer inside the adsorption bed, which is the main obstacle to commercialization...
Show moreA global challenge is to develop environmentally friendly, affordable, compact and sustainable technologies to provide heating and cooling power. Adsorption cooling (AC) technology is one of the most promising ways to solve the environmental issues and cut down the energy consumption related to the traditional air conditioning and refrigeration systems. However, AC systems still suffer from poor heat and mass transfer inside the adsorption bed, which is the main obstacle to commercialization of adsorption cooling units. The main goal of this study is designing an efficient adsorption cooling cycle. In this research work, an in-depth scaling analysis of heat and mass transfer in an adsorption packed bed has been performed to identify and quantify how the effective thermal diffusivity of an adsorption bed and the surface diffusion rate of an adsorbate in a nanoporous adsorbent affect the specific cooling power of an adsorption cooling system. The main goal of this study is to derive new scaling parameters that can be used to specify the optimal bed dimensions and select the appropriate adsorbate/adsorbent pair to achieve the maximum cooling power. As the choice of a suitable working pair is critical for an adsorption cooling cycle, an experimental setup is designed and built to measure the adsorption kinetics and isotherms of any working pair accurately. This setup is also able to measure the dynamic performance of an adsorption bed. The equilibrium uptakes of Fuji silica-gels Type-RD and RD-2060 (manufactured by Fuji Silysia, Japan), which are commonly used in adsorption cooling systems, are measured experimentally. Based on the adsorption rate and the adsorbent temperature measured simultaneously, a new approach is proposed to measure the surface diffusivity in the temperature and pressure ranges typical of those during the operating conditions of adsorption cooling systems. In addition, the experimental measurements from the lab-scale adsorption bed are used to validate the numerical models that are commonly used for estimating the SCP of AC cycle. By using the scaling parameters driven from the scaling analysis, a newly designed packed bed for use in AC systems is proposed and evaluated in this research. The proposed design consists of repeated packed bed cells (modules). Each module is an open-cell aluminum foam packed with silica gel to enhance the overall thermal conductivity of the bed from 0.198 to 5.8 W/m.K. the experimental test rig is used to evaluate the performance on the new adsorption bed. The effect of pores per inch (PPI) of the foam, silica-gel particle size, bed height and adsorption isotherm of different types of silica gel on the bed performance are investigated.
Show less - Date Issued
- 2019
- Identifier
- CFE0007422, ucf:52702
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007422
- Title
- Dynamic Behavior and Performance of Different Types of Multi-Effect Desalination Plants.
- Creator
-
Abdelkareem, Mohamed, Chow, Louis, Mansy, Hansen, Das, Tuhin, Duranceau, Steven, University of Central Florida
- Abstract / Description
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Water and energy are two of the most vital resources for the socio-economic development and sustenance of humanity on earth. Desalination of seawater has been practiced for some decades and is a well-established means of water supply. However, this process consumes large amounts of energy and the global energy supply is also faced with some challenges. In this research, multi-effect desalination (MED) has been selected due to lower cost, lower operating temperature and efficient in terms of...
Show moreWater and energy are two of the most vital resources for the socio-economic development and sustenance of humanity on earth. Desalination of seawater has been practiced for some decades and is a well-established means of water supply. However, this process consumes large amounts of energy and the global energy supply is also faced with some challenges. In this research, multi-effect desalination (MED) has been selected due to lower cost, lower operating temperature and efficient in terms of primary energy and electricity consumption compared to other thermal desalination systems. The motivation for this research is to address thermo-economics and dynamic behavior of different MED feed configurations with/without vapor compression (VC). A new formulation for the steady-state models was developed to simulate different MED systems. Adding a thermal vapor compressor (TVC) or mechanical vapor compression (MVC) unit to the MED system is also studied to show the advantage of this type of integration. For MED-TVC systems, results indicate that the parallel cross feed (PCF) configuration has better performance characteristics than other configurations. A similar study of MED-MVC systems indicates that the PCF and forward feed (FF) configurations require less work to achieve equal distillate production. Reducing the steam temperature supplied by the MVC unit leads to an increase in second law efficiency and a decrease in specific power consumption (SPC) and total water price. Following the fact that the MED may be exposed to fluctuations (disturbances) in input parameters during operation. Therefore, there is a requirement to analyze their transient behavior. In the current study, the dynamic model is developed based on solving the basic conservation equations of mass, energy, and salt. In the case of heat source disturbance, MED plants operating in the backward feed (BF) may be exposed to shut down due to flooding in the first effect. For all applied disturbances, the change in the brine level is the slowest compared to the changes in vapor temperature, and brine and vapor flow rates. For MED-TVC, it is recommended to limit the seawater cooling flow rate reduction to under 12% of the steady-state value to avoid dryout in the evaporators. A reduction in the motive steam flow rate and cooling seawater temperature of more than 20% and 35% of steady-state values, respectively, may lead to flooding in evaporators and plant shutdown. Simultaneous combinations of two different disturbances with opposing effects have only a modest effect on plant operation and they can be used to control and mitigate the flooding/drying effects caused by the disturbances. For the MED-MVC, the compressor work reduction could lead to plant shutdown, while a reduction in the seawater temperature will lead to a reduction in plant production and an increase in SPC.
Show less - Date Issued
- 2019
- Identifier
- CFE0007423, ucf:52735
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007423
- Title
- Size, Charge and Dose Dependent In-vitro Kinetics of Polystyrene Nanoparticles.
- Creator
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Abdellatif, Yasmine, Gesquiere, Andre, Kang, Hyeran, Rajaraman, Swaminathan, University of Central Florida
- Abstract / Description
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The aim of the study described herein is to quantify the in-vitro kinetics of internalization of polystyrene nanoparticles (PS NPs) by cells. We used different charges, sizes and doses of fluorescently labelled PS NPs. Nanoparticles were characterized with UV-Vis, Fluorescence emission Dynamic Light Scattering (DLS) and Zeta potential for knowing their absorption, fluorescence spectra, size, charge, respectively. Additionally, cell viability was tested to know the toxicity of PS NPs. The...
Show moreThe aim of the study described herein is to quantify the in-vitro kinetics of internalization of polystyrene nanoparticles (PS NPs) by cells. We used different charges, sizes and doses of fluorescently labelled PS NPs. Nanoparticles were characterized with UV-Vis, Fluorescence emission Dynamic Light Scattering (DLS) and Zeta potential for knowing their absorption, fluorescence spectra, size, charge, respectively. Additionally, cell viability was tested to know the toxicity of PS NPs. The quantitative uptake, the kinetics profile and rate of uptake were studied by using a new in-vitro fluorescence assay. This was achieved quantitatively and qualitatively by fluorescent plate reader and confocal imaging, respectively. It was found that the amine PS NPs are higher in cytotoxicity than the carboxy PS NPs due to the proton sponge phenomenon. It was observed that the fraction uptake of PS NPs changes by changing the physiochemical properties as charge, size (&) dose. The fraction uptake of neutral and amine PS NPs was higher than that of carboxy PS NPs. For the neutral PS NPs, the uptake depends on the macropinocytosis. For the amine PS NPs, the uptake depends on the electrostatic interaction and the rapid regeneration of new binding sites. Regarding the dose of PS NPs, for the amine PS NPs, it was found that the concentrations lower and higher than 5nM had lower fraction uptake, because the 5nM achieved the balance between the available number of binding sites and the rapid regeneration of new binding sites. For the kinetics profile of the amine and carboxy PS NPs, by comparing both of them, it was observed that the rate of uptake of applied doses lower than 5nM was different, but higher than 5nM was similar. However, for the neutral Ps NPs, they exhibit a steady state of rate of uptake in between the amine and carboxy PS NPs. Also, it was confirmed by the confocal images that as the concentration of amine PS NPs increase, the stress on the cells increase, leading to the cell death. These results were aligned with the results obtained from the cytotoxicity test.
Show less - Date Issued
- 2018
- Identifier
- CFE0007386, ucf:52744
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007386
- Title
- TIMP-1 ACTIVATES A UNIQUE CARDIAC STEM CELL POPULATION, CD63+ve/C-KIT+ve, THEREBY ENHANCING CARDIAC DIFFERENTIATION, AND PROTECTS THE HEART FROM ADVERSE CARDIAC REMODELING FOLLOWING MYOCARDIAL INFARCTION.
- Creator
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Abdelli, Latifa, Singla, Dinender, Cheng, Zixi, Parthasarathy, Sampath, Jewett, Mollie, University of Central Florida
- Abstract / Description
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We previously demonstrated that embryonic stem (ES) cells over-expressing tissue inhibitor of metalloproteinase-1 (TIMP-1) have increased potential to engraft and differentiate into cardiac myocytes following transplantation into the infarcted heart. However, the ability of TIMP-1 to activate endogenous stem cells and enhance their differentiation into cardiac regenerative cell types is still unknown. We postulate that TIMP-1 may additionally activate a stem cell population that enhances...
Show moreWe previously demonstrated that embryonic stem (ES) cells over-expressing tissue inhibitor of metalloproteinase-1 (TIMP-1) have increased potential to engraft and differentiate into cardiac myocytes following transplantation into the infarcted heart. However, the ability of TIMP-1 to activate endogenous stem cells and enhance their differentiation into cardiac regenerative cell types is still unknown. We postulate that TIMP-1 may additionally activate a stem cell population that enhances cardiac cell type differentiation in the infarcted myocardium. To prove this hypothesis, we isolated c-kit+ve cells from four weeks old C57BL/6 mice and cultured them in vitro in presence of ES conditioned media (ESCM), ES-TIMP-1-CM or TIMP-1. Our immunostaining data validate the existence of a novel CD63+ve/c-kit+ve cells. When treated with TIMP-1, these cells showed significantly (p(<)0.05) increased proliferation and differentiation into cardiac myocytes, vascular smooth muscle cells, and endothelial cells. Western blot analysis revealed significantly (p(<)0.05) increased expression of CD63, phosphorylated and total ?-catenin proteins. Furthermore, our RT-PCR data showed increased cardiac gene expression (GATA-4, Mef2C, and Nkx-2.5) when compared to ESCM and control cells. Based on the in vitro findings, we investigated the effect of intramyocardial delivery of TIMP-1 on endogenous CD63+ve/c-kit+ve cells following myocardial infarction (MI). C57BL/6 and TIMP-1 KO mice underwent coronary artery ligation followed by intramyocardial delivery of 20(&)#181;l of culture media (CC), ESCM, ES-TIMP-1-CM or TIMP-1. Subsequent immunohistochemistry analysis demonstrated the presence of a CD63+ve/c-kit+ve cell population within the peri-infarct area and confirmed intramyocardial delivery of ES-TIMP-1-CM or TIMP-1 significantly (p(<)0.05) enhanced their proliferation. Percentage of CD63+ve/c-kit+ve cells was significantly (p(<)0.05) lower in TIMP-1 KO mice compared to C57BL/6 animals. RT-PCR analysis revealed TIMP-1 KO animals expressed significantly less CD63 and TIMP-1 mRNAs compared to C57BL/6 mice. Activated CD63+ve/c-kit+ve cells were also able to differentiate into major cardiac cell types as previously shown in vitro. The differentiation potential of these cells was however higher in C57BL/6 mice compared to TIMP-1 KO mice. We also demonstrate that CD63+ve/c-kit+ve cells differentiation is regulated by CD63/?-catenin pathway in vivo. Additionally, we provide evidence that TIMP-1 protects the heart from adverse cardiac remodeling through inhibition of cardiac apoptosis and fibrosis leading to significantly (p(<)0.05) improved contractile function. Collectively, our data show TIMP-1 plays a dual protective role in the MI heart. It activates a unique stem cell population, CD63+ve/c-kit+ve, which proliferates and differentiates into functional myocytes, smooth muscle cells and endothelial cells mediated through CD63/?-catenin pathway. TIMP-1 also protects the heart from adverse cardiac remodeling. Increased cardiac regeneration and inhibition of adverse cardiac remodeling consequently lead to restored cardiac function. ?
Show less - Date Issued
- 2015
- Identifier
- CFE0005750, ucf:50108
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005750
- Title
- Biomass density based adjustment of LiDAR-derived digital elevation models: a machine learning approach.
- Creator
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Abdelwahab, Khalid, Medeiros, Stephen, Mayo, Talea, Wahl, Thomas, University of Central Florida
- Abstract / Description
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Salt marshes are valued for providing protective and non-protective ecosystem services. Accurate digital elevation models (DEMs) in salt marshes are crucial for modeling storm surges and determining the initial DEM elevations for modelling marsh evolution. Due to high biomass density, lidar DEMs in coastal wetlands are seldom reliable. In an aim to reduce lidar-derived DEM error, several multilinear regression and random forest models were developed and tested to estimate biomass density in...
Show moreSalt marshes are valued for providing protective and non-protective ecosystem services. Accurate digital elevation models (DEMs) in salt marshes are crucial for modeling storm surges and determining the initial DEM elevations for modelling marsh evolution. Due to high biomass density, lidar DEMs in coastal wetlands are seldom reliable. In an aim to reduce lidar-derived DEM error, several multilinear regression and random forest models were developed and tested to estimate biomass density in the salt marshes near Saint Marks Lighthouse in Crawfordville, Florida. Between summer of 2017 and spring of 2018, two field trips were conducted to acquire true elevation and biomass density measures. Lidar point cloud data were combined with vegetation monitoring imagery acquired from Sentinel-2 and Landsat Thematic Mapper (LTM) satellites, and 64 field biomass density samples were used as target variables for developing the models. Biomass density classes were assigned to each biomass sample using a quartile approach. Moreover, 346 in-situ elevation measures were used to calculate the lidar DEM errors. The best model was then used to estimate biomass densities at all 346 locations. Finally, an adjusted DEM was produced by deducting the quartile-based adjustment values from the original lidar DEM. A random forest regression model achieved the highest pseudo R2 value of 0.94 for predicting biomass density in g/m2. The adjusted DEM based on the estimated biomass densities reduced the root mean squared error of the original DEM from 0.38 m to 0.18 m while decreasing the raw mean error from 0.33 m to 0.14 m, improving both measures by 54% and 58%, respectively.
Show less - Date Issued
- 2019
- Identifier
- CFE0007594, ucf:52535
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007594
- Title
- SELF DESIGNING PATTERN RECOGNITION SYSTEM EMPLOYING MULTISTAGE CLASSIFICATION.
- Creator
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ABDELWAHAB, MANAL MAHMOUD, Mikhael, Wasfy, University of Central Florida
- Abstract / Description
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Recently, pattern recognition/classification has received a considerable attention in diverse engineering fields such as biomedical imaging, speaker identification, fingerprint recognition, etc. In most of these applications, it is desirable to maintain the classification accuracy in the presence of corrupted and/or incomplete data. The quality of a given classification technique is measured by the computational complexity, execution time of algorithms, and the number of patterns that can be...
Show moreRecently, pattern recognition/classification has received a considerable attention in diverse engineering fields such as biomedical imaging, speaker identification, fingerprint recognition, etc. In most of these applications, it is desirable to maintain the classification accuracy in the presence of corrupted and/or incomplete data. The quality of a given classification technique is measured by the computational complexity, execution time of algorithms, and the number of patterns that can be classified correctly despite any distortion. Some classification techniques that are introduced in the literature are described in Chapter one.In this dissertation, a pattern recognition approach that can be designed to have evolutionary learning by developing the features and selecting the criteria that are best suited for the recognition problem under consideration is proposed. Chapter two presents some of the features used in developing the set of criteria employed by the system to recognize different types of signals. It also presents some of the preprocessing techniques used by the system. The system operates in two modes, namely, the learning (training) mode, and the running mode. In the learning mode, the original and preprocessed signals are projected into different transform domains. The technique automatically tests many criteria over the range of parameters for each criterion. A large number of criteria are developed from the features extracted from these domains. The optimum set of criteria, satisfying specific conditions, is selected. This set of criteria is employed by the system to recognize the original or noisy signals in the running mode. The modes of operation and the classification structures employed by the system are described in details in Chapter three.The proposed pattern recognition system is capable of recognizing an enormously large number of patterns by virtue of the fact that it analyzes the signal in different domains and explores the distinguishing characteristics in each of these domains. In other words, this approach uses available information and extracts more characteristics from the signals, for classification purposes, by projecting the signal in different domains. Some experimental results are given in Chapter four showing the effect of using mathematical transforms in conjunction with preprocessing techniques on the classification accuracy. A comparison between some of the classification approaches, in terms of classification rate in case of distortion, is also given.A sample of experimental implementations is presented in chapter 5 and chapter 6 to illustrate the performance of the proposed pattern recognition system. Preliminary results given confirm the superior performance of the proposed technique relative to the single transform neural network and multi-input neural network approaches for image classification in the presence of additive noise.
Show less - Date Issued
- 2004
- Identifier
- CFE0000020, ucf:46077
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000020
- Title
- NOVEL FACIAL IMAGE RECOGNITION TECHNIQUES EMPLOYINGPRINCIPAL COMPONENT ANALYSIS.
- Creator
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ABDELWAHAB, MOATAZ, Mikhael, Wasfy, University of Central Florida
- Abstract / Description
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Recently, pattern recognition/classification has received considerable attention in diverse engineering fields such as biomedical imaging, speaker identification, fingerprint recognition, and face recognition, etc. This study contributes novel techniques for facial image recognition based on the Two dimensional principal component analysis in the transform domain. These algorithms reduce the storage requirements by an order of magnitude and the computational complexity by a factor of 2 while...
Show moreRecently, pattern recognition/classification has received considerable attention in diverse engineering fields such as biomedical imaging, speaker identification, fingerprint recognition, and face recognition, etc. This study contributes novel techniques for facial image recognition based on the Two dimensional principal component analysis in the transform domain. These algorithms reduce the storage requirements by an order of magnitude and the computational complexity by a factor of 2 while maintaining the excellent recognition accuracy of the recently reported methods. The proposed recognition systems employ different structures, multicriteria and multitransform. In addition, principal component analysis in the transform domain in conjunction with vector quantization is developed which result in further improvement in the recognition accuracy and dimensionality reduction. Experimental results confirm the excellent properties of the proposed algorithms.
Show less - Date Issued
- 2007
- Identifier
- CFE0001977, ucf:47465
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001977
- Title
- High Average Power Nanosecond Pulsed Tm:Fiber Laser for Pumping an Optical Parametric Oscillator.
- Creator
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Abdulfattah, Ali, Richardson, Martin, Shah, Lawrence, Delfyett, Peter, University of Central Florida
- Abstract / Description
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Thulium-doped fiber lasers operating with wavelengths in the vicinity of 2 (&)#181;m are useful for several emerging applications including generating mid-IR light via nonlinear frequency conversion. In this study we describe the design and construction of a thulium fiber laser system comprising a master oscillator and a power amplifier. The first stage is a Q-switched, thulium-doped photonic crystal fiber oscillator utilizing an acousto-optic modulator to produce 65-80 nanosecond pulses. A...
Show moreThulium-doped fiber lasers operating with wavelengths in the vicinity of 2 (&)#181;m are useful for several emerging applications including generating mid-IR light via nonlinear frequency conversion. In this study we describe the design and construction of a thulium fiber laser system comprising a master oscillator and a power amplifier. The first stage is a Q-switched, thulium-doped photonic crystal fiber oscillator utilizing an acousto-optic modulator to produce 65-80 nanosecond pulses. A diffraction grating in the cavity provides wavelength tunability from 1.8 (-) 2?m. The oscillator produced up to 3 W of average power and 150 (&)#181;J pulse energies, corresponding to 2.3 kW peak powers. The amplifier stage consists of a large mode area, thulium-doped, step-index fiber seeded with powers up to 2 W from the oscillator. An output energy of 700 (&)#181;J with 81 ns pulse width, was achieved at a wavelength of 1.9 (&)#181;m. The effect of the fiber holder temperature on the amplifier performance relative to output pulse energy and seed wavelength was also studied. As a part of this thesis, a methodology has been developed to thoroughly characterize Tm:fiber amplifier performance. This has been the subject of prior work by several research groups, however, this work explicitly focuses on the precise characterization of absorbed pump power, pump bleaching, and extracted amplified energy for a range of input seeds power, pulse energy, and wavelength in order to better understand amplifier performance.
Show less - Date Issued
- 2016
- Identifier
- CFE0006240, ucf:51065
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006240