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- Title
- Placement of Mode and Wavelength Converters for Throughput Enhancement in Optical Networks.
- Creator
-
Abdulrahman, Ruaa, Bassiouni, Mostafa, Chatterjee, Mainak, Zou, Changchun, University of Central Florida
- Abstract / Description
-
The success of recent experiments to transport data using combined wavelength division multiplexed (WDM) and mode-division multiplexed (MDM) transmission has generated optimism for the attainment of optical networks with unprecedented bandwidth capacity, exceeding the fundamental Shannon capacity limit attained by WDM alone. Optical mode converters and wavelength converters are devices that can be placed in future optical nodes (routers) to prevent or reduce the connection blocking rate and...
Show moreThe success of recent experiments to transport data using combined wavelength division multiplexed (WDM) and mode-division multiplexed (MDM) transmission has generated optimism for the attainment of optical networks with unprecedented bandwidth capacity, exceeding the fundamental Shannon capacity limit attained by WDM alone. Optical mode converters and wavelength converters are devices that can be placed in future optical nodes (routers) to prevent or reduce the connection blocking rate and consequently increase network throughput. In this thesis, the specific problem of the placement of mode converters (MC) and mode-wavelength converters (MWC) in combined mode and wavelength division multiplexing (MWDM) networks is investigated. Four previously proposed wavelength converter placement heuristics are extended to handle the placement of MC and MWC in MWDM networks. A simple but effective method for the placement of mode and wavelength converters in MWDM networks is proposed based on ranking the nodes with respect to the volume of received connection requests. The results of extensive simulation tests to evaluate the new method and compare its performance with the performance of the other four heuristics are presented. The thesis provides extensive comparison results among the five converter placement methods using different network topologies and under different network loads. The results demonstrate the effectiveness of the new proposed method in achieving lower blocking rates compared to the other more-complex converter placement heuristics.
Show less - Date Issued
- 2014
- Identifier
- CFE0005118, ucf:50756
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005118
- Title
- IMPACT OF LANDSCAPE MANAGEMENT ON HOUSE MICE (MUS MUSCULUS) AND RED IMPORTED FIRE ANTS (SOLENOPSIS INVICTA).
- Creator
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Abelson, Jesse, Jenkins, David, University of Central Florida
- Abstract / Description
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Understanding of mechanisms that limit the abundance and distribution of species is central to ecology. The failure of mechanisms to regulate populations can result in population outbreaks. There have been two outbreaks of house mice in the past decade in central Florida. In my study, I examine the efficacy of landscape management in the form of mowing and plowed soil barriers to limit or prevent outbreaks of house mice in a former agricultural area. House mouse populations were highly...
Show moreUnderstanding of mechanisms that limit the abundance and distribution of species is central to ecology. The failure of mechanisms to regulate populations can result in population outbreaks. There have been two outbreaks of house mice in the past decade in central Florida. In my study, I examine the efficacy of landscape management in the form of mowing and plowed soil barriers to limit or prevent outbreaks of house mice in a former agricultural area. House mouse populations were highly variable, but were unaffected by mowing or plowed soil barriers. Red imported fire ants were ubiquitous in the study area regardless of land management treatments. Control of fire ants did not result in more house mice on treated plots.
Show less - Date Issued
- 2011
- Identifier
- CFE0003590, ucf:48899
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003590
- Title
- Investigating the universality and comprehensive ability of measures to assess the state of workload.
- Creator
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Abich, Julian, Reinerman, Lauren, Lackey, Stephanie, Szalma, James, Taylor, Grant, University of Central Florida
- Abstract / Description
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Measures of workload have been developed on the basis of the various definitions, some are designed to capture the multi-dimensional aspects of a unitary resource pool (Kahneman, 1973) while others are developed on the basis of multiple resource theory (Wickens, 2002). Although many theory based workload measures exist, others have often been constructed to serve the purpose of specific experimental tasks. As a result, it is likely that not every workload measure is reliable and valid for all...
Show moreMeasures of workload have been developed on the basis of the various definitions, some are designed to capture the multi-dimensional aspects of a unitary resource pool (Kahneman, 1973) while others are developed on the basis of multiple resource theory (Wickens, 2002). Although many theory based workload measures exist, others have often been constructed to serve the purpose of specific experimental tasks. As a result, it is likely that not every workload measure is reliable and valid for all tasks, much less each domain. To date, no single measure, systematically tested across experimental tasks, domains, and other measures is considered a universal measure of workload. Most researchers would argue that multiple measures from various categories should be applied to a given task to comprehensively assess workload. The goal for Study 1 to establish task load manipulations for two theoretically different tasks that induce distinct levels of workload assessed by both subjective and performance measures was successful. The results of the subjective responses support standardization and validation of the tasks and demands of that task for investigating workload. After investigating the use of subjective and objective measures of workload to identify a universal and comprehensive measure or set of measures, based on Study 2, it can only be concluded that not one or a set of measures exists. Arguably, it is not to say that one will never be conceived and developed, but at this time, one does not reside in the psychometric catalog. Instead, it appears that a more suitable approach is to customize a set of workload measures based on the task. The novel approach of assessing the sensitivity and comprehensive ability of conjointly utilizing subjective, performance, and physiological workload measures for theoretically different tasks within the same domain contributes to the theory by laying the foundation for improving methodology for researching workload. The applicable contribution of this project is a stepping-stone towards developing complex profiles of workload for use in closed-loop systems, such as human-robot team interaction. Identifying the best combination of workload measures enables human factors practitioners, trainers, and task designers to improve methodology and evaluation of system designs, training requirements, and personnel selection.
Show less - Date Issued
- 2013
- Identifier
- CFE0005119, ucf:50675
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005119
- Title
- Study of Transport Phenomena in Carbon-Based Materials.
- Creator
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Aboelsoud, Walid, Chow, Louis, Kumar, Ranganathan, Deng, Weiwei, Kar, Aravinda, University of Central Florida
- Abstract / Description
-
In air-cooled heat exchangers, air-side thermal resistance is usually the largest compared to conduction and liquid-side thermal resistances. Thus, reducing the air-side thermal resistance with fin-like structures can greatly improve overall cooling performance. The performance of these structures is usually characterized by the rate of heat which can be transferred and the pumping power required. One promising solution is to use a high-thermal-conductivity material with a large surface per...
Show moreIn air-cooled heat exchangers, air-side thermal resistance is usually the largest compared to conduction and liquid-side thermal resistances. Thus, reducing the air-side thermal resistance with fin-like structures can greatly improve overall cooling performance. The performance of these structures is usually characterized by the rate of heat which can be transferred and the pumping power required. One promising solution is to use a high-thermal-conductivity material with a large surface per unit volume such as carbon foam. This study presents a method of utilizing V-shape corrugated carbon foam. The air-side heat transfer coefficient and the pressure drop across the foam have been investigated using different V-shape foam geometrical configurations obtained by varying its length and height. Based on design considerations and availability, the foam length has been chosen to be 25.4, 38.1 and 52.1 mm while its height is 4.4, 6.8 and 11.7 mm, resulting in nine different test pieces of foam with different heights and lengths.A total number of 81 experiments were carried out and results show that of the nine V-shape configurations, the foam with the shortest length and tallest height gives the best performance. Experimental results are also compared with the results of prior work using different carbon foam geometries. It is shown that V-shape corrugated carbon foam provides higher heat transfer coefficient and better overall performance.Numerical method is performed next. The effect of the foam length and height on thermal and hydraulic performance is demonstrated and discussed. There is excellent agreement between numerical and experimental results. An analysis is also made to better understand the transport phenomena that occur within the porous matrix. For laminar flow of air, one of the findings is the high heat transfer effectiveness of the foam which means a foam thickness of 1 mm or less is sufficient for heat transfer enhancement for air speed of up to 4 m/s. To demonstrate the feasibility of using carbon foam, an analytical case study of carbon foam heat exchanger was performed and compared to traditional heat exchanger with the same heat load. Results show that a volume saving of up to 55% can be obtained by using carbon foam instead of traditional aluminum fins.Another attractive carbon-based material is the highly oriented pyrolytic graphite (HOPG) which has an in-plane thermal conductivity of about 1700 W/m.K and an out-of-plane k of about 8 W/m.K at room temperature. HOPG is a graphite material with a high degree of preferred crystallographic orientation. HOPG can be very useful in thermal applications when axial conduction is critical and needed to be minimized as in recuperators used in cryocoolers and compact power generation. Also, an analysis of HOPG for micro-channel applications shows that the high in-plane thermal conductivity of HOPG, which is far greater than that of copper and aluminum, allows a taller height for the micro-channel. This translates to an increase in the heat flux removal rate by two to three times.
Show less - Date Issued
- 2013
- Identifier
- CFE0005081, ucf:50732
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005081
- Title
- Task Focused Robotic Imitation Learning.
- Creator
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Abolghasemi, Pooya, Boloni, Ladislau, Sukthankar, Gita, Shah, Mubarak, Willenberg, Bradley, University of Central Florida
- Abstract / Description
-
For many years, successful applications of robotics were the domain of controlled environments, such as industrial assembly lines. Such environments are custom designed for the convenience of the robot and separated from human operators. In recent years, advances in artificial intelligence, in particular, deep learning and computer vision, allowed researchers to successfully demonstrate robots that operate in unstructured environments and directly interact with humans. One of the major...
Show moreFor many years, successful applications of robotics were the domain of controlled environments, such as industrial assembly lines. Such environments are custom designed for the convenience of the robot and separated from human operators. In recent years, advances in artificial intelligence, in particular, deep learning and computer vision, allowed researchers to successfully demonstrate robots that operate in unstructured environments and directly interact with humans. One of the major applications of such robots is in assistive robotics. For instance, a wheelchair mounted robotic arm can help disabled users in the performance of activities of daily living (ADLs) such as feeding and personal grooming. Early systems relied entirely on the control of the human operator, something that is difficult to accomplish by a user with motor and/or cognitive disabilities. In this dissertation, we are describing research results that advance the field of assistive robotics. The overall goal is to improve the ability of the wheelchair / robotic arm assembly to help the user with the performance of the ADLs by requiring only high-level commands from the user. Let us consider an ADL involving the manipulation of an object in the user's home. This task can be naturally decomposed into two components: the movement of the wheelchair in such a way that the manipulator can conveniently grasp the object and the movement of the manipulator itself. This dissertation we provide an approach for addressing the challenge of finding the position appropriate for the required manipulation. We introduce the ease-of-reach score (ERS), a metric that quantifies the preferences for the positioning of the base while taking into consideration the shape and position of obstacles and clutter in the environment. As the brute force computation of ERS is computationally expensive, we propose a machine learning approach to estimate the ERS based on features and characteristics of the obstacles. This dissertation addresses the second component as well, the ability of the robotic arm to manipulate objects. Recent work in end-to-end learning of robotic manipulation had demonstrated that a deep learning-based controller of vision-enabled robotic arms can be thought to manipulate objects from a moderate number of demonstrations. However, the current state of the art systems are limited in robustness to physical and visual disturbances and do not generalize well to new objects. We describe new techniques based on task-focused attention that show significant improvement in the robustness of manipulation and performance in clutter.
Show less - Date Issued
- 2019
- Identifier
- CFE0007771, ucf:52392
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007771
- Title
- Microscopic Assessment of Transportation Emissions on Limited Access Highways.
- Creator
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Abou-Senna, Hatem, Radwan, Ahmed, Abdel-Aty, Mohamed, Al-Deek, Haitham, Cooper, Charles, Johnson, Mark, University of Central Florida
- Abstract / Description
-
On-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have...
Show moreOn-road vehicles are a major source of transportation carbon dioxide (CO2) greenhouse gas emissions in all the developed countries, and in many of the developing countries in the world. Similarly, several criteria air pollutants are associated with transportation, e.g., carbon monoxide (CO), nitrogen oxides (NOx), and particulate matter (PM). The need to accurately quantify transportation-related emissions from vehicles is essential. Transportation agencies and researchers in the past have estimated emissions using one average speed and volume on a long stretch of roadway. With MOVES, there is an opportunity for higher precision and accuracy. Integrating a microscopic traffic simulation model (such as VISSIM) with MOVES allows one to obtain precise and accurate emissions estimates. The new United States Environmental Protection Agency (USEPA) mobile source emissions model, MOVES2010a (MOVES) can estimate vehicle emissions on a second-by-second basis creating the opportunity to develop new software (")VIMIS 1.0(") (VISSIM/MOVES Integration Software) to facilitate the integration process. This research presents a microscopic examination of five key transportation parameters (traffic volume, speed, truck percentage, road grade and temperature) on a 10-mile stretch of Interstate 4 (I-4) test bed prototype; an urban limited access highway corridor in Orlando, Florida. The analysis was conducted utilizing VIMIS 1.0 and using an advanced custom design technique; D-Optimality and I-Optimality criteria, to identify active factors and to ensure precision in estimating the regression coefficients as well as the response variable.The analysis of the experiment identified the optimal settings of the key factors and resulted in the development of Micro-TEM (Microscopic Transportation Emissions Meta-Model). The main purpose of Micro-TEM is to serve as a substitute model for predicting transportation emissions on limited access highways to an acceptable degree of accuracy in lieu of running simulations using a traffic model and integrating the results in an emissions model. Furthermore, significant emission rate reductions were observed from the experiment on the modeled corridor especially for speeds between 55 and 60 mph while maintaining up to 80% and 90% of the freeway's capacity. However, vehicle activity characterization in terms of speed was shown to have a significant impact on the emission estimation approach.Four different approaches were further examined to capture the environmental impacts of vehicular operations on the modeled test bed prototype. First, (at the most basic level), emissions were estimated for the entire 10-mile section (")by hand(") using one average traffic volume and average speed. Then, three advanced levels of detail were studied using VISSIM/MOVES to analyze smaller links: average speeds and volumes (AVG), second-by-second link driving schedules (LDS), and second-by-second operating mode distributions (OPMODE). This research analyzed how the various approaches affect predicted emissions of CO, NOx, PM and CO2. The results demonstrated that obtaining accurate and comprehensive operating mode distributions on a second-by-second basis improves emission estimates. Specifically, emission rates were found to be highly sensitive to stop-and-go traffic and the associated driving cycles of acceleration, deceleration, frequent braking/coasting and idling. Using the AVG or LDS approach may overestimate or underestimate emissions, respectively, compared to an operating mode distribution approach.Additionally, model applications and mitigation scenarios were examined on the modeled corridor to evaluate the environmental impacts in terms of vehicular emissions and at the same time validate the developed model (")Micro-TEM("). Mitigation scenarios included the future implementation of managed lanes (ML) along with the general use lanes (GUL) on the I-4 corridor, the currently implemented variable speed limits (VSL) scenario as well as a hypothetical restricted truck lane (RTL) scenario. Results of the mitigation scenarios showed an overall speed improvement on the corridor which resulted in overall reduction in emissions and emission rates when compared to the existing condition (EX) scenario and specifically on link by link basis for the RTL scenario.The proposed emission rate estimation process also can be extended to gridded emissions for ozone modeling, or to localized air quality dispersion modeling, where temporal and spatial resolution of emissions is essential to predict the concentration of pollutants near roadways.
Show less - Date Issued
- 2012
- Identifier
- CFE0004777, ucf:49788
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004777
- Title
- Growth and doping of MoS2 thin films for electronic and optoelectronic applications.
- Creator
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Abouelkhair, Hussain, Peale, Robert, Kaden, William, Stolbov, Sergey, Coffey, Kevin, University of Central Florida
- Abstract / Description
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MoS2 high absorption coefficient, high mobility, mechanical flexibility, and chemical inertness is very promising for many electronic and optoelectronic applications. The growth of high-quality MoS2 by a scalable and doping compatible method is still lacking. Therefore, the suitable dopants for MoS2 are not fully explored yet. This dissertation consists mainly of four main studies. The first study is on the growth of MoS2 thin films by atmospheric pressure chemical vapor deposition. Scanning...
Show moreMoS2 high absorption coefficient, high mobility, mechanical flexibility, and chemical inertness is very promising for many electronic and optoelectronic applications. The growth of high-quality MoS2 by a scalable and doping compatible method is still lacking. Therefore, the suitable dopants for MoS2 are not fully explored yet. This dissertation consists mainly of four main studies. The first study is on the growth of MoS2 thin films by atmospheric pressure chemical vapor deposition. Scanning electron microscope images revealed the growth of microdomes of MoS2 on top of a smooth MoS2 film. These microdomes are very promising as a broadband omnidirectional light trap for light harvesting applications. The second study is on the growth of MoS2 thin films by low pressure chemical vapor deposition (LPCVD). Control of sulfur vapor flow is essential for the growth of a pure phase of MoS2. Turning off sulfur vapor flow during the cooling cycle at 700 (&)#186;C leads to the growth of highly textured MoS2 with a Hall mobility of 20 cm2/Vs. The third study was on the growth of Ti-doped MoS2 thin films by LPCVD. The successful doping was confirmed by Hall effect measurement and secondary ion mass spectrometry (SIMS). Different growth temperatures from 1000 to 700 ? were studied. Ti act as a donor in MoS2. The fourth study is on fluorine-doped SnO2 (FTO) which has many technological applications including solar cells and transistors. FTO was grown by an aqueous-spray-based method. The main objective was to compare the actual against the nominal concentration of fluorine using SIMS. The concentration of fluorine in the grown films is lower than the concentration of fluorine in the aqueous solution.?
Show less - Date Issued
- 2017
- Identifier
- CFE0006847, ucf:51767
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006847
- Title
- Applied Software Tools for Supporting Children with Intellectual Disabilities.
- Creator
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Abualsamid, Ahmad, Hughes, Charles, Dieker, Lisa, Sims, Valerie, Wiegand, Rudolf, University of Central Florida
- Abstract / Description
-
We explored the level of technology utilization in supporting children with cognitive disabilities at schools, speech clinics, and with assistive communication at home. Anecdotal evidence, literature research, and our own survey of special needs educators in Central Florida reveal that use of technology is minimal in classrooms for students with special needs even when scientific research has shown the effectiveness of video modeling in teaching children with special needs new skills and...
Show moreWe explored the level of technology utilization in supporting children with cognitive disabilities at schools, speech clinics, and with assistive communication at home. Anecdotal evidence, literature research, and our own survey of special needs educators in Central Florida reveal that use of technology is minimal in classrooms for students with special needs even when scientific research has shown the effectiveness of video modeling in teaching children with special needs new skills and behaviors. Research also shows that speech and language therapists utilize a manual approach to elicit and analyze language samples from children with special needs. While technology is utilized in augmentative and alternative communication, many caregivers utilize paper-based picture exchange systems, storyboards, and daily schedules when assisting their children with their communication needs. We developed and validated three software frameworks to aid language therapists, teachers, and caregivers in supporting children with cognitive disabilities and related special needs. The Analysis of Social Discourse Framework proposes that language therapists use social media discourse instead of direct elicitation of language samples. The framework presents an easy-to-use approach to analyzing language samples based on natural language processing. We validated the framework by analyzing public social discourse from three unrelated sources. The Applied Interventions for eXceptional-needs (AIX) framework allows classroom teachers to implement and track interventions using easy-to-use smartphone applications. We validated the framework by conducting a sixteen-week pilot case study in a school for students with special needs in Central Florida. The Language Enhancements for eXceptioanl Youth (LEXY) framework allows for the development of a new class of augmentative and alternative communication tools that are based on conversational chatbots that assist children with special needs while utilizing a model of the world curated by their caregivers. We validated the framework by simulating an interaction between a prototype chatbot that we developed, a child with special needs, and the child's caregiver.
Show less - Date Issued
- 2018
- Identifier
- CFE0006964, ucf:52908
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006964
- Title
- Integrating Multiobjective Optimization with the Six Sigma Methodology for Online Process Control.
- Creator
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Abualsauod, Emad, Geiger, Christopher, Elshennawy, Ahmad, Thompson, William, Moore, Karla, University of Central Florida
- Abstract / Description
-
Over the past two decades, the Define-Measure-Analyze-Improve-Control (DMAIC) framework of the Six Sigma methodology and a host of statistical tools have been brought to bear on process improvement efforts in today's businesses. However, a major challenge of implementing the Six Sigma methodology is maintaining the process improvements and providing real-time performance feedback and control after solutions are implemented, especially in the presence of multiple process performance objectives...
Show moreOver the past two decades, the Define-Measure-Analyze-Improve-Control (DMAIC) framework of the Six Sigma methodology and a host of statistical tools have been brought to bear on process improvement efforts in today's businesses. However, a major challenge of implementing the Six Sigma methodology is maintaining the process improvements and providing real-time performance feedback and control after solutions are implemented, especially in the presence of multiple process performance objectives. The consideration of a multiplicity of objectives in business and process improvement is commonplace and, quite frankly, necessary. However, balancing the collection of objectives is challenging as the objectives are inextricably linked, and, oftentimes, in conflict.Previous studies have reported varied success in enhancing the Six Sigma methodology by integrating optimization methods in order to reduce variability. These studies focus these enhancements primarily within the Improve phase of the Six Sigma methodology, optimizing a single objective. The current research and practice of using the Six Sigma methodology and optimization methods do little to address the real-time feedback and control for online process control in the case of multiple objectives.This research proposes an innovative integrated Six Sigma multiobjective optimization (SSMO) approach for online process control. It integrates the Six Sigma DMAIC framework with a nature-inspired optimization procedure that iteratively perturbs a set of decision variables providing feedback to the online process, eventually converging to a set of tradeoff process configurations that improves and maintains process stability. For proof of concept, the approach is applied to a general business process model (-) a well-known inventory management model (-) that is formally defined and specifies various process costs as objective functions. The proposed SSMO approach and the business process model are programmed and incorporated into a software platform. Computational experiments are performed using both three sigma (3?)-based and six sigma (6?)-based process control, and the results reveal that the proposed SSMO approach performs far better than the traditional approaches in improving the stability of the process. This research investigation shows that the benefits of enhancing the Six Sigma method for multiobjective optimization and for online process control are immense.
Show less - Date Issued
- 2013
- Identifier
- CFE0004968, ucf:49561
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004968
- Title
- Evaluation and Modeling of the Safety of Open Road Tolling System.
- Creator
-
Abuzwidah, Muamer, Abdel-Aty, Mohamed, Radwan, Ahmed, Uddin, Nizam, University of Central Florida
- Abstract / Description
-
The goal of this thesis is to examine the traffic safety impact of upgrading Toll Plazas (TP) to Open Road Tolling (ORT). The ORT could enhance safety but could also pose some traffic safety concerns at Toll plazas. Crashes from eight years were investigated by evaluating the crash data before and after the implementation of the ORT.The study was conducted by using two approaches: 1) a simple before and after study and with a comparison group; 2) a modeling effort to help understand the...
Show moreThe goal of this thesis is to examine the traffic safety impact of upgrading Toll Plazas (TP) to Open Road Tolling (ORT). The ORT could enhance safety but could also pose some traffic safety concerns at Toll plazas. Crashes from eight years were investigated by evaluating the crash data before and after the implementation of the ORT.The study was conducted by using two approaches: 1) a simple before and after study and with a comparison group; 2) a modeling effort to help understand the relationship between the crash frequency and several important factors and circumstances such as injury severity, collision types, average daily traffic (ADT) and Toll plaza characteristics. The study investigated 11 Toll plazas on State Roads 408, 417, 528 and 429 that have been changed to the ORT design. Several maps showing the Toll plazas and identifying the relevant crash locations were generated. Negative Binomial (NB), Log Linear model and two-way contingency table were examined. Two log-linear models with three variables in each model with all possible two-way interactions were developed. Categorical data analysis of the 2009 and 2010 crash dataset was performed. In order to compare the differences in response between the crash frequency and a particular crash-related variable, odds ratios were computed. The effects of crash frequency and crash-related factors were examined, and interactions among them were considered. The results indicated significant relationships between the crash frequency and ADT, crash type and driver age.It is worth mentioning that the expressway network understudy was continuously experiencing constructions throughout the study period. There is indication that ORT reduced the total crash number; also there is indication of changing the crash types and locations; and the majority of crashes occurred at the diverging and merging areas and resulted in more severe crashes. More data may be needed to confirm these results especially after all constructions and upgrades are made.The Implementation of open road tolling, the locations of Toll plazas, Automatic Vehicle Identification (AVI) subscription rate, traffic demand, and plaza geometry all may have a high influence on traffic safety concerns at Toll plazas, as concluded from the negative Binomial Model's results. The changing of sign locations, reducing the speed limit, installing variable message signs, configuring plazas properly, and other considerations may be the solution to overcome the potential safety problems in the vicinity of Toll plazas.The change of design to ORT was proven to be an excellent solution to several traffic operation problems, including reducing congestion and improving traffic flow and capacity at Toll plazas. However, addressing safety concerns at Toll plazas should take priority.
Show less - Date Issued
- 2011
- Identifier
- CFE0004466, ucf:49330
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004466
- Title
- TRAFFIC SAFETY ASSESSMENT OF DIFFERENT TOLL COLLECTION SYSTEMS ON EXPRESSWAYS USING MULTIPLE ANALYTICAL TECHNIQUES.
- Creator
-
Abuzwidah, Muamer, Abdel-Aty, Mohamed, Radwan, Essam, Uddin, Nizam, University of Central Florida
- Abstract / Description
-
Traffic safety has been considered one of the most important issues in the transportation field. Crashes have caused extensive human and economic losses. With the objective of reducing crash occurrence and alleviating crash injury severity, major efforts have been dedicated to reveal the hazardous factors that affect crash occurrence. With these consistent efforts, both fatalities and fatality rates from road traffic crashes in many countries have been steadily declining over the last ten...
Show moreTraffic safety has been considered one of the most important issues in the transportation field. Crashes have caused extensive human and economic losses. With the objective of reducing crash occurrence and alleviating crash injury severity, major efforts have been dedicated to reveal the hazardous factors that affect crash occurrence. With these consistent efforts, both fatalities and fatality rates from road traffic crashes in many countries have been steadily declining over the last ten years. Nevertheless, according to the World Health Organization, the world still lost 1.24 million lives from road traffic crashes in the year of 2013. And without action, traffic crashes on the roads network are predicted to result in deaths of around 1.9 million people, and up to 50 million more people suffer non-fatal injuries annually, with many incurring a disability as a result of their injury by the year 2020. To meet the transportation needs, the use of expressways (toll roads) has risen dramatically in many countries in the past decade. In fact, freeways and expressways are considered an important part of any successful transportation system. These facilities carry the majority of daily trips on the transportation network. Although expressways offer high level of service, and are considered the safest among other types of roads, traditional toll collection systems may have both safety and operational challenges. The traditional toll plazas still experience many crashes, many of which are severe. Therefore, it becomes more important to evaluate the traffic safety impacts of using different tolling systems. The main focus of the research in this dissertation is to provide an up-to-date safety impact of using different toll collection systems, as well as providing safety guidelines for these facilities to promote safety and enhance mobility on expressways. In this study, an extensive data collection was conducted that included one hundred mainline toll plazas located on approximately 750 miles of expressways in Florida. Multiple sources of data available online maintained by Florida Department of Transportation were utilized to identify traffic, geometric and geographic characteristics of the locations as well as investigating and determination of the most complete and accurate data. Different methods of observational before-after and Cross-Sectional techniques were used to evaluate the safety effectiveness of applying different treatments on expressways. The Before-After method includes Na(&)#239;ve Before-After, Before-After with Comparison Group, and Before-After with Empirical Bayesian. A set of Safety Performance Functions (SPFs) which predict crash frequency as a function of explanatory variables were developed at the aggregate level using crash data and the corresponding exposure and risk factors. Results of the aggregate traffic safety analysis can be used to identify the hazardous locations (hot spots) such as traditional toll plazas, and also to predict crash frequency for untreated sites in the after period in the Before-After with EB method or derive Crash Modification Factors (CMF) for the treatment using the Cross-Sectional method. This type of analysis is usually used to improve geometric characteristics and mainly focus on discovering the risk factors that are related to the total crash frequency, specific crash type, and/or different crash severity levels. Both simple SPFs (with traffic volume only as an explanatory variable) and full SPFs (with traffic volume and additional explanatory variable(s)) were used to estimate the CMFs and only CMFs with lower standard error were recommended.The results of this study proved that safety effectiveness was significantly improved across all locations that were upgraded from Traditional Mainline Toll Plazas (TMTP) to the Hybrid Mainline Toll Plazas (HMTP) system. This treatment significantly reduced total, Fatal-and-Injury (F+I), and Rear-End crashes by 47, 46 and 65 percent, respectively. Moreover, this study examined the traffic safety impact of using different designs, and diverge-and-merge areas of the HMTP. This design combines either express Open Road Tolling (ORT) lanes on the mainline and separate traditional toll collection to the side (design-1), or traditional toll collection on the mainline and separate ORT lanes to the side (design-2). It was also proven that there is a significant difference between these designs, and there is an indication that design-1 is safer and the majority of crashes occurred at diverge-and-merge areas before and after these facilities. However, design-2 could be a good temporary design at locations that have low prepaid transponder (Electronic Toll Collection (ETC)) users. In other words, it is dependent upon the percentage of the ETC users. As this percentage increases, more traffic will need to diverge and merge; thus, this design becomes riskier. In addition, the results indicated significant relationships between the crash frequency and toll plaza types, annual average daily traffic, and drivers' age. The analysis showed that the conversion from TMTP to the All-Electronic Toll Collection (AETC) system resulted in an average reduction of 77, 76, and 67 percent for total, F+I, and Property Damage Only (PDO) crashes, respectively; for rear end and Lane Change Related (LCR) crashes the average reductions were 81 and 75 percent, respectively. The conversion from HMTP to AETC system enhanced traffic safety by reducing crashes by an average of 23, 29 and 19 percent for total, F+I, and PDO crashes; also, for rear end and LCR crashes, the average reductions were 15 and 21 percent, respectively. Based on these results, the use of AETC system changed toll plazas from the highest risk sections on Expressways to be similar to regular segments. Therefore, it can be concluded that the use of AETC system was proven to be an excellent solution to several traffic operations as well as environmental and economic problems. For those agencies that cannot adopt the HMTP and the AETC systems, improving traffic safety at traditional toll plazas should take a priority.This study also evaluates the safety effectiveness of the implementation of High-Occupancy Toll lanes (HOT Lanes) as well as adding roadway lighting to expressways. The results showed that there were no significant impact of the implementation of HOT lanes on the roadway segment as a whole (HOT and Regular Lanes combined). But there was a significant difference between the regular lanes and the HOT lanes at the same roadway segment; the crash count increased at the regular lanes and decreased at the HOT lanes. It was found that the total and F+I crashes were reduced at the HOT lanes by an average of 25 and 45 percent, respectively. This may be attributable to the fact that the HOT lanes became a highway within a highway. Moreover adding roadway lighting has significantly improved traffic safety on the expressways by reducing the night crashes by approximately 35 percent.Overall, the proposed analyses of the safety effectiveness of using different toll collection systems are useful in providing expressway authorities with detailed information on where countermeasures must be implemented. This study provided for the first time an up-to-date safety impact of using different toll collection systems, also developed safety guidelines for these systems which would be useful for practitioners and roadway users.
Show less - Date Issued
- 2014
- Identifier
- CFE0005751, ucf:50100
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005751
- Title
- DESIGN AND PERFORMANCE EVALUATION OF AN INTEGRATED MINIATURE SINGLE STAGE CENTRIFUGAL COMPRESSOR AND PERMANENT MAGNET SYNCHRONOUS MOTOR.
- Creator
-
ACHARYA, DIPJYOTI, Kapat, Jayanta, University of Central Florida
- Abstract / Description
-
An attempt has been made in this present work to design, fabricate and performance evaluate an integrated single stage centrifugal compressor and permanent magnet synchronous motor which is a key component of the reverse brayton cycle cryocooler. An off the shelf compressor the driven and electric motor the driver was not available commercially to suffice the requirements of the reverse brayton cryocooler. The integrated compressor-motor system was designed and tested with air...
Show moreAn attempt has been made in this present work to design, fabricate and performance evaluate an integrated single stage centrifugal compressor and permanent magnet synchronous motor which is a key component of the reverse brayton cycle cryocooler. An off the shelf compressor the driven and electric motor the driver was not available commercially to suffice the requirements of the reverse brayton cryocooler. The integrated compressor-motor system was designed and tested with air as the working fluid at mass flow rate of 7.3 grams per sec, with a compression ratio of 1.58 and driven by a 2 KW permanent magnet synchronous motor at a design speed of 108,000 rpm. A permanent magnet synchronous motor rotor was designed to operate to operate over 200,000 rpm at 77 Kelvin temperature. It involved iterative processes involving structural, thermal and rotordynamic analysis of the rotor. Selection of high speed ceramic ball bearings, their mounting, fit and pre-load played prominent role. Attempts were made to resolve misalignment issues for the compressor motor system, which had severe impact on the rotordynamic performance of the system and therefore losses at high speeds , . A custom designed flexible coupler was designed and fabricated to run the compressor motor system. An integrated compressor motor system was an innovative design to resolve considerably several factors which hinder a high operational speed. Elimination of the coupler, reduction of number of bearings in the system and usage of fewer components on the rotor to increase the stiffness were distinct features of the integrated system. Several custom designed test-rigs were built which involved precision translation stages and angle brackets. Motor control software, an emulator, a DSP and a custom designed motor controller was assembled to run the motor. A cooling system was specially designed to cool the stator rotor system. A pre-loading structure was fabricated to adequately pre-load the bearings. Flow measurement instruments such as mass flow meter, pressure transducers and thermocouples were used at several locations on the test rig to monitor the flow. An adjustable inlet guide vane was designed to control the tip clearance of the impeller.
Show less - Date Issued
- 2006
- Identifier
- CFE0001207, ucf:46955
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001207
- Title
- Modeling Autocorrelation and Sample Weights in Panel Data: A Monte Carlo Simulation Study.
- Creator
-
Acharya, Parul, Sivo, Stephen, Hahs-Vaughn, Debbie, Witta, Eleanor, Butler, Malcolm, University of Central Florida
- Abstract / Description
-
This dissertation investigates the interactive or joint influence of autocorrelative processes (autoregressive-AR, moving average-MA, and autoregressive moving average-ARMA) and sample weights present in a longitudinal panel data set. Specifically, to what extent are the sample estimates influenced when autocorrelation (which is usually present in a panel data having correlated observations and errors) and sample weights (complex sample design feature used in longitudinal data having multi...
Show moreThis dissertation investigates the interactive or joint influence of autocorrelative processes (autoregressive-AR, moving average-MA, and autoregressive moving average-ARMA) and sample weights present in a longitudinal panel data set. Specifically, to what extent are the sample estimates influenced when autocorrelation (which is usually present in a panel data having correlated observations and errors) and sample weights (complex sample design feature used in longitudinal data having multi-stage sampling design) are modeled versus when they are not modeled or either one of them is taken into account. The current study utilized a Monte Carlo simulation design to vary the type and magnitude of autocorrelative processes and sample weights as factors incorporated in growth or latent curve models to evaluate the effect on sample latent curve estimates (mean intercept, mean slope, intercept variance, slope variance, and intercept slope correlation). Various latent curve models with weights or without weights were specified with an autocorrelative process and then fitted to data sets having either the AR, MA or ARMA process. The relevance and practical importance of the simulation results were ascertained by testing the joint influence of autocorrelation and weights on the Early Childhood Longitudinal Study for Kindergartens (ECLS-K) data set which is a panel data set having complex sample design features. The results indicate that autocorrelative processes and weights interact with each other as sources of error to a statistically significant degree. Accounting for just the autocorrelative process without weights or utilizing weights while ignoring the autocorrelative process may lead to bias in the sample estimates particularly in large-scale datasets in which these two sources of error are inherently embedded. The mean intercept and mean slope of latent curve models without weights was consistently underestimated when fitted to data sets having AR, MA or ARMA process. On the other hand, the intercept variance, intercept slope, and intercept slope correlation were overestimated for latent curve models with weights. However, these three estimates were not accurate as the standard errors associated with them were high. In addition, fit indices, AR and MA estimates, parsimony of the model, behavior of sample latent curve estimates, and interaction effects between autocorrelative processes and sample weights should be assessed for all the models before a particular model is deemed as most appropriate. If the AR estimate is high and MA estimate is low for a LCAR model than the other models that are fitted to a data set having sample weights and the fit indices are in the acceptable cut-off range, then the data set has a higher likelihood of having an AR process between the observations. If the MA estimate is high and AR estimate is low for a LCMA model than the other models that are fitted to a data set having sample weights and the fit indices are in the acceptable cut-off range, then the data set has a higher likelihood of having an MA process between the observations. If both AR and MA estimates are high for a LCARMA model than the other models that are fitted to a data set having sample weights and the fit indices are in the acceptable cut-off range, then the data set has a higher likelihood of having an ARMA process between the observations. The results from the current study recommends that biases from both autocorrelation and sample weights needs to be simultaneously modeled to obtain accurate estimates. The type of autocorrelation (AR, MA or ARMA), magnitude of autocorrelation, and sample weights influences the behavior of estimates and all the three facets should be carefully considered to correctly interpret the estimates especially in the context of measuring growth or change in the variable(s) of interest over time in large-scale longitudinal panel data sets.
Show less - Date Issued
- 2015
- Identifier
- CFE0005914, ucf:50850
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005914
- Title
- From Excited Charge Dynamics to Cluster Diffusion: Development and Application of Techniques Beyond DFT and KMC.
- Creator
-
Acharya, Shree Ram, Rahman, Talat, Chow, Lee, Stolbov, Sergey, Wu, Annie, University of Central Florida
- Abstract / Description
-
This dissertation focuses on developing reliable and accurate computational techniques which enable the examination of static and dynamic properties of various activated phenomena using deterministic and stochastic approaches. To explore ultrafast electron dynamics in materials with strong electron-electron correlation, under the influence of a laser pulse, an ab initio electronic structure method based on time-dependent density functional theory (TDDFT) in combination with dynamical mean...
Show moreThis dissertation focuses on developing reliable and accurate computational techniques which enable the examination of static and dynamic properties of various activated phenomena using deterministic and stochastic approaches. To explore ultrafast electron dynamics in materials with strong electron-electron correlation, under the influence of a laser pulse, an ab initio electronic structure method based on time-dependent density functional theory (TDDFT) in combination with dynamical mean field theory (DMFT) is developed and applied to: 1) single-band Hubbard model; 2) multi-band metal Ni; and 3) multi-band insulator MnO. The ultrafast demagnetization in Ni reveal the importance of memory and correlation effects, leading to much better agreement with experimental data than previously obtained, while for MnO the main channels of charge response are identified. Furthermore, an analytical form of the exchange-correlation kernel is obtained for future applications, saving tremendous computational cost. In another project, size-dependent temporal and spatial evolution of homo- and hetero-epitaxial adatom islands on fcc(111) transition metals surfaces are investigated using the self-learning kinetic Monte Carlo (SLKMC) method that explores long-time dynamics unbiased by apriori selected diffusion processes. Novel multi-atom diffusion processes are revealed. Trends in the diffusion coefficients point to the relative role of adatom lateral interaction and island-substrate binding energy in determining island diffusivity. Moreover, analysis of the large data-base of the activation energy barriers generated for multitude of diffusion processes for variety of systems allows extraction of a set of descriptors that in turn generate predictive models for energy barrier evaluation. Finally, the kinetics of the industrially important methanol partial oxidation reaction on a model nanocatalyst is explored using KMC supplemented by DFT energetics. Calculated thermodynamics explores the active surface sites for reaction components including different intermediates and energetics of competing probable reaction pathways, while kinetic study attends to the selectivity of products and its variation with external factors.
Show less - Date Issued
- 2018
- Identifier
- CFE0006965, ucf:52910
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006965
- Title
- INTERNATIONAL CONTRACTS: A QUANTITATIVE ANALYSIS OF TRANSNATIONAL CONTRACT FORMATION.
- Creator
-
Ackerman, David, Browm, Cynthia, University of Central Florida
- Abstract / Description
-
Globalization is the promise of the future, and it presents, quite literally, a world of opportunities not available in the past. International collaborations in science, research, and business now enjoy increased probabilities of success, in part, because of the advance in technology and the possibility of instantaneous communications. The convenience, simplicity and affordability of technology are helping to make the world accessible to almost everyone. With new availability of...
Show moreGlobalization is the promise of the future, and it presents, quite literally, a world of opportunities not available in the past. International collaborations in science, research, and business now enjoy increased probabilities of success, in part, because of the advance in technology and the possibility of instantaneous communications. The convenience, simplicity and affordability of technology are helping to make the world accessible to almost everyone. With new availability of international concerns and the growth of global partnerships in all areas of interest, an increased need arises for agreements that memorialize collaborators' commitments, responsibilities and obligations. There is a corresponding concern that the agreements be enforceable across national and international lines should anything go wrong. There is no collaboration, partnership or venture that will not be touched in some way by the law. Whose law governs and how rules and regulations of different nations will be applied are of escalating concern. Empirically examining the state of international contract law is the overarching focus of my research. Adopting a research methodology involving both quantitative and qualitative techniques, I am investigating whether any consistency exists between attorneys of different practice sectors (academic, government, corporate and private) considering choice of law, enforcement of contract provisions, and the inclusion of preventative measures of international contracts. My results contribute to the future success of international collaborations of all concerns by empirically identifying the need for increased education on various dispute resolution options, as well as the effect cultural awareness has on the drafting of international contracts.
Show less - Date Issued
- 2011
- Identifier
- CFH0003845, ucf:44686
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0003845
- Title
- SOCIAL WORK STUDENTS' COMFORT WITHGAY AND LESBIAN FAMILIES.
- Creator
-
Ackerman, Jennifer, School of Social Work, Dr. Ana Leon, University of Central Florida
- Abstract / Description
-
Despite recent advancements in legislation and policies regarding gay and lesbian Americans, negative attitudes and perceptions toward this population still exist. Anecdotal information from social work classroom interactions suggests that biases against gays and lesbian families may exist among those being trained as helping professionals. This study examined social work student comfort with gay and lesbian families. The researcher used an exploratory-descriptive research design, with a...
Show moreDespite recent advancements in legislation and policies regarding gay and lesbian Americans, negative attitudes and perceptions toward this population still exist. Anecdotal information from social work classroom interactions suggests that biases against gays and lesbian families may exist among those being trained as helping professionals. This study examined social work student comfort with gay and lesbian families. The researcher used an exploratory-descriptive research design, with a sample of 85 Bachelors level social work students (BSW) and Masters level social work students (MSW) who completed the 52 item online questionnaire related to gay and lesbian parenting. The findings from the research suggest the presence of a statistically significant relationship between students' attitudes towards gays and lesbians and students' comfort level with same sex parents. The researcher discusses the significance of the study and the implications for social work practice and education.
Show less - Date Issued
- 2013
- Identifier
- CFH0004344, ucf:45019
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004344
- Title
- The relationship among post-traumatic growth, religious commitment, and optimism in adult Liberian former refugees and internally displaced persons traumatized by war-related events.
- Creator
-
Acquaye, Hannah, Jones, Dayle, Robinson, Edward, Van Horn, Stacy, Sivo, Stephen, University of Central Florida
- Abstract / Description
-
One of the myriad consequences of war is displacement and refugee-ism. People become refugees when they no longer feel safe in their country of origin. Before, during, and after the journey towards safety, refugees and internally displaced persons (IDPs) endure several challenging circumstances which stretch their normal abilities to cope. In their efforts to cope, these people report several mental health challenges like sleeplessness, hypervigilance, anxiety, and depression. The reported...
Show moreOne of the myriad consequences of war is displacement and refugee-ism. People become refugees when they no longer feel safe in their country of origin. Before, during, and after the journey towards safety, refugees and internally displaced persons (IDPs) endure several challenging circumstances which stretch their normal abilities to cope. In their efforts to cope, these people report several mental health challenges like sleeplessness, hypervigilance, anxiety, and depression. The reported mental health challenges are normal in this population; however, when they persist, they result in posttraumatic stress disorder. Surprisingly, some also report obtaining psychological growth due to their challenging circumstances. To examine the interplay of posttraumatic stress disorder and psychological growth in this population, the study was grounded on the cognitive theory of trauma and the broaden-and-build theory of positive emotions. Thus, the relationship among posttraumatic growth, religious commitment, and optimism within adult Liberian former refugees and IDPs traumatized by war-related events became the focus of the investigation. The grounding theories provided four hypotheses that explored the relationship among the constructs, as well as seven exploratory research questions that identified differences among participants. Through purposeful and snowball sampling methods, five hundred participants were selected as the sample; 444 returned the study package. Participants were adult Liberian former refugees and IDPs who could read and understand English at the 8th grade level, and who lived in Monrovia. Participants completed six instruments (-) the Posttraumatic Growth Inventory, the Religious Commitment Inventory, the Revised Life Orientation Test, the War Trauma Screening Index, the Posttraumatic Stress Disorder Checklist for DSM-5, and demographic questionnaire. Results of the study indicated that there was a statistically significant correlation between impact of war-related events and posttraumatic stress disorder, with alterations in arousal and reactivity obtaining the strongest correlation. However, the presence of posttraumatic stress disorder for the Liberian sample could be attributed to the recent reaction to the Ebola virus which re-traumatized adult Liberian former refugees and IDPs. Furthermore, there was a statistically significant relationship between all factors of posttraumatic stress disorder and all factors of posttraumatic growth. The relationship between factors of religious commitment and factors of posttraumatic stress disorder was statistically significant for some posttraumatic stress disorder factors and not significant for others. Similarly, relationship between optimism and posttraumatic stress disorder was statistically significant for some and not significant for others. Finally, a structural equation model was conducted to identify latent variables affecting the relationship. Results indicated, as per the hypothesized model, that war events predicted trauma, which in turn predicted posttraumatic growth. However, even though religiousness and optimism could each predict posttraumatic growth, optimism, more than religiousness provided errors that co-varied with errors of trauma, indicating that with the presence of optimism, a person could move from trauma towards growth. Review of related literature situated the current study in the mental health discourse, especially in providing a voice for mental health on the African continent. Detailed methodology was provided, as were results of findings. Finally, summary, conclusions, and recommendations were provided for both mental health workers, counselor educators, and researchers.
Show less - Date Issued
- 2016
- Identifier
- CFE0006241, ucf:51077
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006241
- Title
- THE ACADEMIC ACHIEVEMENT OF AFRICAN-AMERICAN STUDENTS IN ORANGE COUNTY PUBLIC HIGH SCHOOLS.
- Creator
-
Adams, Athena, Taylor, Rosemarye, University of Central Florida
- Abstract / Description
-
The study was conducted to determine the disparity between the academic achievement of African American students and the academic achievement of white American students in the state of Florida, and more specifically, in five high schools in Orange County Public Schools. The term "African American" included all students who self-identified as that race upon enrollment into an Orange County public school. The study included male and female African American students from different socio-economic...
Show moreThe study was conducted to determine the disparity between the academic achievement of African American students and the academic achievement of white American students in the state of Florida, and more specifically, in five high schools in Orange County Public Schools. The term "African American" included all students who self-identified as that race upon enrollment into an Orange County public school. The study included male and female African American students from different socio-economic levels. The term "differences in academic achievement" is most commonly referred to as "achievement gap." Additionally, this study sought to determine the relationship, if any, in the achievement of African American students' academic achievement in five high schools in Orange County Public Schools, Orlando, Florida. In addition, the purpose was to identify differences in achievement level based upon the school attended, gender, socio-economic levels, class size, and qualifications of the teachers. The methods and procedures used to determine if there was an achievement gap between African-American and white American high school students was to review: (a) gain in African-American students on the reading portion of the Florida Comprehensive Assessment Test, from the 2003-2004 administration to the 2004-2005 administration in five Orange County public high schools, (b) difference between African-American students' 2004-2005 reading portion of the Florida Comprehensive Assessment Test percentage at proficient (level 3 and above) and white American students in five public high schools in Orange, (c) the relationship between African-American students' 2004-2005 reading portion of the Florida Comprehensive Assessment Test percent at proficient (level 3 and above) and the school poverty rate in all public high schools in Orange County, (d) the characteristics of schools making gains in reading. There were four conclusions based on the review of literature, as well as the data collected from the five high schools. Under the provision and penalties attached to the No Child Left Behind legislation, there was a noticeable gap in achievement between African-American students and their white American counterparts in each of the examined schools over a two year time period. In schools with a greater percentage of white students, African-American students, overall, performed at a higher level. The achievement gap was narrower and the percent at proficient and above was higher for all students in schools where white students represented a greater percentage of the students. In schools with a lower percentage of students on free and/or reduced lunch, the percent of students reading at proficient or above was higher and the achievement gap was less between African-American students and their white counterparts. Furthermore, the data indicated that as the percent of students on free and reduced lunch at a given school increases, the rate of those reading at proficient and above for African-American students was lower. In schools with a wide array of diversity, students overall have higher achievement scores. Based on the data in the study, the school with the highest rate of student proficient and above, was the school with the greatest diversity population of students.
Show less - Date Issued
- 2008
- Identifier
- CFE0002148, ucf:47511
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002148
- Title
- SOCIAL MEDIA AND ITS EFFECT ON PRIVACY.
- Creator
-
Adams, Brittney, Flammia, Madelyn, University of Central Florida
- Abstract / Description
-
While research has been conducted on social media, few comparisons have been made in regards to the privacy issues that exist within the most common social media networks, such as Facebook, Google Plus, and Twitter. Most research has concentrated on technical issues with the networks and on the effects of social media in fields such as medicine, law, and science. Although the effects on these fields are beneficial to the people related to them, few studies have shown how everyday users are...
Show moreWhile research has been conducted on social media, few comparisons have been made in regards to the privacy issues that exist within the most common social media networks, such as Facebook, Google Plus, and Twitter. Most research has concentrated on technical issues with the networks and on the effects of social media in fields such as medicine, law, and science. Although the effects on these fields are beneficial to the people related to them, few studies have shown how everyday users are affected by the use of social media. Social media networks affect the privacy of users because the networks control what happens to user contact information, posts, and other delicate disclosures that users make on those networks. Social media networks also have the ability to sync with phone and tablet applications. Because the use of these applications requires additional contact information from users, social media networks are entrusted with keeping user information secure. This paper analyzes newspaper articles, magazine articles, and research papers pertaining to social media to determine what effects social media has on the user's privacy and how much trust should be placed in social media networks such as Facebook. It provides a comprehensive view of the most used social media networks in 2012 and offers methods and suggestions for users to help protect themselves against privacy invasion.
Show less - Date Issued
- 2012
- Identifier
- CFH0004242, ucf:44895
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004242