View All Items
(41 - 53 of 53)
Pages
- Title
- Boitawl: Soil, Lost and Left.
- Creator
-
Chowdhuri, Bishnupriya, Milanes, Cecilia, Thaxton, Terry, Roney, Lisa, University of Central Florida
- Abstract / Description
-
Boitawl ???? ((")Boi(")- lack, devoid of, (")Tawl(")- bottom/ ground/ foundation), the word in one of the Bengali dialects refers to one without a ground beneath her feet. The thesis, a hybrid collection of prose and verse including narratives and graphic vignettes, flash, fabulist and short stories, prose poems and free verse imagines the inside worlds of such un-settled existences. In the process, the pieces connect migration, memory, childhood and lost towns with fractured humans caught in...
Show moreBoitawl ???? ((")Boi(")- lack, devoid of, (")Tawl(")- bottom/ ground/ foundation), the word in one of the Bengali dialects refers to one without a ground beneath her feet. The thesis, a hybrid collection of prose and verse including narratives and graphic vignettes, flash, fabulist and short stories, prose poems and free verse imagines the inside worlds of such un-settled existences. In the process, the pieces connect migration, memory, childhood and lost towns with fractured humans caught in between(-)to reveal what lies under pillars of desires, the shapes of unsaid longings and recurrent images in their dreams.?
Show less - Date Issued
- 2018
- Identifier
- CFE0007320, ucf:52122
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007320
- Title
- A MULTISCALE MODEL OF THE NEONATAL CIRCULATORY SYSTEM FOLLOWING HYBRID NORWOOD PALLIATION.
- Creator
-
Ceballos, Andres, Kassab, Alain, University of Central Florida
- Abstract / Description
-
Hypoplastic left heart syndrome (HLHS) is a complex cardiac malformation in neonates suffering from congenital heart disease and occurs in nearly 1 per 5000 births. HLHS is uniformly fatal within the first hours or days after birth as the severely malformed anatomies of the left ventricle, mitral and aortic valves, and ascending aorta are not compatible with life. The regularly implemented treatment, the Norwood operation, is a complex open heart procedure that attempts to establish...
Show moreHypoplastic left heart syndrome (HLHS) is a complex cardiac malformation in neonates suffering from congenital heart disease and occurs in nearly 1 per 5000 births. HLHS is uniformly fatal within the first hours or days after birth as the severely malformed anatomies of the left ventricle, mitral and aortic valves, and ascending aorta are not compatible with life. The regularly implemented treatment, the Norwood operation, is a complex open heart procedure that attempts to establish univentricular circulation by removing the atrial septum (communicating the right and left ventricle), reconstructing the malformed aortic arch, and connecting the main pulmonary artery into the reconstructed arch to allow direct perfusion from the right ventricle into the systemic circulation. A relatively new treatment being utilized, the Hybrid Norwood procedure, involves a less invasive strategy to establish univentricular circulation that avoids a cardiopulmonary bypass (heart-lung machine), deliberate cardiac arrest, and circulatory arrest of the patient during the procedure. The resulting systemic-pulmonary circulation is unconventional; blood is pumped simultaneously and in parallel to the systemic and pulmonary arteries after the procedure. Cardiac surgeons are deeply interested in understanding the global and local hemodynamics of this anatomical configuration. To this end, a multiscale model of the entire circulatory system was developed utilizing an electrical lumped parameter model for the peripheral or distal circulation coupled with a 3D Computational Fluid Dynamics (CFD) model to understand the local hemodynamics. The lumped parameter (LP) model is mainly a closed loop circuit comprised of RLC compartments that model cardiac function as well as the viscous drag, flow inertia, and compliance of the different arterial and venous beds in the body. A system of 32 first-order differential equations is formulated and solved for the LP model using a fourth-order adaptive Runge-Kutta solver. The output pressure and flow waveforms obtained from the LP model are imposed as boundary conditions on the CFD model. Coupling of the two models is done through an iterative process where the parameters in the LP model are adjusted to match the CFD solution. The CFD model domain is a representative HLHS anatomy of an infant after undergoing the Hybrid Norwood procedure and is comprised of the neo-aorta, pulmonary roots, aortic arch with branching arteries, and pulmonary arteries. The flow field is solved over several cardiac cycles using an implicit-unsteady RANS equation solver with the k-epsilon turbulence model.
Show less - Date Issued
- 2011
- Identifier
- CFE0004037, ucf:49183
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004037
- Title
- A Hybrid Simulation Framework of Consumer-to-Consumer Ecommerce Space.
- Creator
-
Joledo, Oloruntomi, Rabelo, Luis, Lee, Gene, Elshennawy, Ahmad, Ajayi, Richard, University of Central Florida
- Abstract / Description
-
In the past decade, ecommerce transformed the business models of many organizations. Information Technology leveled the playing field for new participants, who were capable of causing disruptive changes in every industry. (")Web 2.0(") or (")Social Web(") further redefined ways users enlist for services. It is now easy to be influenced to make choices of services based on recommendations of friends and popularity amongst peers. This research proposes a simulation framework to investigate how...
Show moreIn the past decade, ecommerce transformed the business models of many organizations. Information Technology leveled the playing field for new participants, who were capable of causing disruptive changes in every industry. (")Web 2.0(") or (")Social Web(") further redefined ways users enlist for services. It is now easy to be influenced to make choices of services based on recommendations of friends and popularity amongst peers. This research proposes a simulation framework to investigate how actions of stakeholders at this level of complexity affect system performance as well as the dynamics that exist between different models using concepts from the fields of operations engineering, engineering management, and multi-model simulation. Viewing this complex model from a systems perspective calls for the integration of different levels of behaviors. Complex interactions exist among stakeholders, the environment and available technology. The presence of continuous and discrete behaviors coupled with stochastic and deterministic behaviors present challenges for using standalone simulation tools to simulate the business model.We propose a framework that takes into account dynamic system complexity and risk from a hybrid paradigm. The SCOR model is employed to map the business processes and it is implemented using agent based simulation and system dynamics. By combining system dynamics at the strategy level with agent based models of consumer behaviors, an accurate yet efficient representation of the business model that makes for sound basis of decision making can be achieved to maximize stakeholders' utility.
Show less - Date Issued
- 2016
- Identifier
- CFE0006122, ucf:51171
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006122
- Title
- Tailoring Instruction to the individual: Investigating the Utility of Trainee Aptitudes for use in Adaptive Training.
- Creator
-
Landsberg, Carla, Mouloua, Mustapha, Bowers, Clint, Neider, Mark, Van Buskirk, Wendi, University of Central Florida
- Abstract / Description
-
Computer-based training has become more prolific as the military and private businessenterprises search for more efficient ways to deliver training. However, some methods ofcomputer-based training are not more effective than traditional classroom methods. Onetechnique that may be able to approximate the most effective form of training, one-on-onetutoring, is Adaptive Training (AT). AT techniques use instruction that is tailored to the learnerin some way, and can adjust different training...
Show moreComputer-based training has become more prolific as the military and private businessenterprises search for more efficient ways to deliver training. However, some methods ofcomputer-based training are not more effective than traditional classroom methods. Onetechnique that may be able to approximate the most effective form of training, one-on-onetutoring, is Adaptive Training (AT). AT techniques use instruction that is tailored to the learnerin some way, and can adjust different training parameters such as difficulty, feedback, pace, anddelivery mode.There are many ways to adapt training to the learner, and in this study I exploredadapting the feedback provided to trainees based on spatial ability in line with Cognitive LoadTheory (CLT). In line with the CLT expertise reversal effect literature I hypothesized that for aspatial task, higher ability trainees would perform better when they were given less feedback.Alternately, I hypothesized that lower ability trainees would perform better during training whenthey were given more support via feedback. This study also compared two different adaptationapproaches. The first approach, called the ATI approach, adapts feedback based on a premeasuredability. In this case, it was spatial ability. The second approach, called the Hybridapproach adapts initially based on ability, but then based on performance later in training. Ihypothesized that participants who received Hybrid adaptive training would perform better.The study employed a 2(spatial ability; high, low) X 2(feedback; matched, mismatched)X 2 (approach; ATI, Hybrid) between-subjects design in which participants were randomlyassigned to one of the eight conditions. Ninety-two participants completed a submarine-basedperiscope operator task that was visual and spatial in nature. ivThe results of the study did not support the use of CLT-derived adaptation based onspatial ability; contrary to what was hypothesized, higher ability participants who received morefeedback performed better than those who received less. Similarly, lower ability participantswho received less feedback performed better than those who received more. While notsignificant, results suggested there may be some benefit to using the Hybrid approach, but moreresearch is needed to determine the relative effectiveness of this approach.
Show less - Date Issued
- 2015
- Identifier
- CFE0005646, ucf:50191
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005646
- Title
- Cavity-Coupled Plasmonic Systems for Enhanced Light-Matter Interactions.
- Creator
-
Vazquez-Guardado, Abraham, Chanda, Debashis, Christodoulides, Demetrios, Abouraddy, Ayman, Moharam, Jim, Leuenberger, Michael, University of Central Florida
- Abstract / Description
-
Light-matter interaction is a pivotal effect that involves the synergetic interplay of electromag- netic fields with fundamental particles. In this regard localized surface plasmons (LSP) arise from coherent interaction of the electromagnetic field with the collective oscillation of free electrons in confined sub-wavelength environments. Their most attractive properties are strong field en- hancements at the near field, highly inhomogeneous, peculiar temporal and spatial distributions and...
Show moreLight-matter interaction is a pivotal effect that involves the synergetic interplay of electromag- netic fields with fundamental particles. In this regard localized surface plasmons (LSP) arise from coherent interaction of the electromagnetic field with the collective oscillation of free electrons in confined sub-wavelength environments. Their most attractive properties are strong field en- hancements at the near field, highly inhomogeneous, peculiar temporal and spatial distributions and unique polarization properties. LSP systems also offer a unique playground for fundamental electromagnetic physics where micro-scale systemic properties can be studied in the macro-scale. These important properties and opportunities are brought up in this work where I study hybrid cavity-coupled plasmonic systems in which the weak plasmonic element is far-field coupled with the photonic cavity by properly tuning its phase. In this work I preset the fundamental understand- ing of such a complex systems from the multi-resonance interaction picture along experimental demonstration. Using this platform and its intricate near fields I further demonstrate a novel mech- anism to generate superchiral light: a field polarization property that adds a degree of freedom to light-matter interactions at the nanoscale exploited in advanced sensing applications and surface effect processes. Finally, the detection of non-chiral analytes, such as proteins, neurotransmit- ters or nanoparticles, and more complex chiral analytes, such as proteins and its conformation states, amino acids or chiral molecules at low concentrations is demonstrated in several biosensing applications. The accompanied experiential demonstrations were accomplished using the nanoim- printing technique, which places the cavity-coupled hybrid plasmonic system as a unique platform towards realistic applications not limited by expensive lithographic techniques.
Show less - Date Issued
- 2018
- Identifier
- CFE0007418, ucf:52708
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007418
- Title
- Understanding How, Where and How much Freight Flows Using 2012 Commodity Flow Survey Data.
- Creator
-
Keya, Nowreen, Eluru, Naveen, Abdel-Aty, Mohamed, Anowar, Sabreena, Uddin, Nizam, University of Central Florida
- Abstract / Description
-
In recent years, with increased economic globalization, growing e-commerce and internet based shopping, freight movement patterns are undergoing a transformative change. The shipment size distribution is moving towards a higher share of smaller size shipments affecting transportation mode and vehicle type requirements. In addition, freight transportation mode is closely affected by the destination location (and its attributes). In our dissertation, we contribute to freight research by...
Show moreIn recent years, with increased economic globalization, growing e-commerce and internet based shopping, freight movement patterns are undergoing a transformative change. The shipment size distribution is moving towards a higher share of smaller size shipments affecting transportation mode and vehicle type requirements. In addition, freight transportation mode is closely affected by the destination location (and its attributes). In our dissertation, we contribute to freight research by developing a comprehensive framework to examine the how, where and how much freight flows in US. Specifically, we study the following dimensions of freight flow: (1) transportation mode, (2) mode and shipment weight choice and (3) mode and destination choice. For analyzing mode choice, an advanced discrete freight mode choice model- a hybrid utility-regret based model system has been estimated while accommodating for shipper level unobserved heterogeneity. To demonstrate the applicability of the proposed model system, detailed policy analyses examining the implementation of vehicle fleet automation and rerouting of freight movements away from a region were considered. While shipment weight could be considered as an explanatory variable in modeling mode choice (or vice-versa), it is more likely that the decision of mode and shipment choice is a simultaneous process. This joint decision is investigated both simultaneously employing a closed form copula structure and sequentially employing latent segmentation based sequence model. For destination choice, we investigated the connection between shipping mode and destination choice of shipment in a latent segmentation based sequential form. The analysis for the dissertation is conducted using 2012 Commodity Flow Survey (CFS) data.
Show less - Date Issued
- 2018
- Identifier
- CFE0007574, ucf:52569
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007574
- Title
- Heterogeneous Reconfigurable Fabrics for In-circuit Training and Evaluation of Neuromorphic Architectures.
- Creator
-
Mohammadizand, Ramtin, DeMara, Ronald, Lin, Mingjie, Sundaram, Kalpathy, Fan, Deliang, Wu, Annie, University of Central Florida
- Abstract / Description
-
A heterogeneous device technology reconfigurable logic fabric is proposed which leverages the cooperating advantages of distinct magnetic random access memory (MRAM)-based look-up tables (LUTs) to realize sequential logic circuits, along with conventional SRAM-based LUTs to realize combinational logic paths. The resulting Hybrid Spin/Charge FPGA (HSC-FPGA) using magnetic tunnel junction (MTJ) devices within this topology demonstrates commensurate reductions in area and power consumption over...
Show moreA heterogeneous device technology reconfigurable logic fabric is proposed which leverages the cooperating advantages of distinct magnetic random access memory (MRAM)-based look-up tables (LUTs) to realize sequential logic circuits, along with conventional SRAM-based LUTs to realize combinational logic paths. The resulting Hybrid Spin/Charge FPGA (HSC-FPGA) using magnetic tunnel junction (MTJ) devices within this topology demonstrates commensurate reductions in area and power consumption over fabrics having LUTs constructed with either individual technology alone. Herein, a hierarchical top-down design approach is used to develop the HSC(&)#173; FPGA starting from the configurable logic block (CLB) and slice structures down to LUT circuits and the corresponding device fabrication paradigms. This facilitates a novel architectural approach to reduce leakage energy, minimize communication occurrence and energy cost by eliminating unnecessary data transfer, and support auto-tuning for resilience. Furthermore, HSC-FPGA enables new advantages of technology co-design which trades off alternative mappings between emerging devices and transistors at runtime by allowing dynamic remapping to adaptively leverage the intrinsic computing features of each device technology. HSC-FPGA offers a platform for fine-grained Logic-In-Memory architectures and runtime adaptive hardware.An orthogonal dimension of fabric heterogeneity is also non-determinism enabled by either low(&)#173; voltage CMOS or probabilistic emerging devices. It can be realized using probabilistic devices within a reconfigurable network to blend deterministic and probabilistic computational models. Herein, consider the probabilistic spin logic p-bit device as a fabric element comprising a crossbar(&)#173; structured weighted array. The programmability of the resistive network interconnecting p-bit devices can be achieved by modifying the resistive states of the array's weighted connections. Thus, the programmable weighted array forms a CLB-scale macro co-processing element with bitstream programmability. This allows field programmability for a wide range of classification problems and recognition tasks to allow fluid mappings of probabilistic and deterministic computing approaches. In particular, a Deep Belief Network (DBN) is implemented in the field using recurrent layers of co-processing elements to form an n(&)#215; m1(&)#215;m2(&)#215;...(&)#215;mi weighted array as a configurable hardware circuit with an n-input layer followed by i?1 hidden layers. As neuromorphic architectures using post-CMOS devices increase in capability and network size, the utility and benefits of reconfigurable fabrics of neuromorphic modules can be anticipated to continue to accelerate.
Show less - Date Issued
- 2019
- Identifier
- CFE0007502, ucf:52643
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007502
- Title
- Computational Fluid Dynamics Study of Thromboembolism as a Function of Shunt Size and Placement in the Hybrid Norwood Palliative Treatment of Hypoplastic Left Heart Syndrome.
- Creator
-
Seligson, John, Kassab, Alain, DeCampli, William, Mansy, Hansen, University of Central Florida
- Abstract / Description
-
The Hybrid Norwood procedure has emerged as a promising alternative palliative first stage treatment for infants with Hypoplastic Left Heart Syndrome (HLHS). The procedure is done to provide necessary blood flow to the pulmonary and systemic regions of the body. The procedure can affect hemodynamic conditions to be pro-thrombotic, and thrombus particles can form and release from the vessel walls and enter the flow. Assuming these particles are formed and released from the shunt surface, a...
Show moreThe Hybrid Norwood procedure has emerged as a promising alternative palliative first stage treatment for infants with Hypoplastic Left Heart Syndrome (HLHS). The procedure is done to provide necessary blood flow to the pulmonary and systemic regions of the body. The procedure can affect hemodynamic conditions to be pro-thrombotic, and thrombus particles can form and release from the vessel walls and enter the flow. Assuming these particles are formed and released from the shunt surface, a Computational Fluid Dynamics (CFD) model can be used to mimic the patient's vasculature geometry and predict the occurrence of embolization to the carotid or coronary arteries, as well as the other major arteries surrounding the heart. This study used a time dependent, multi-scale CFD analysis on patient-specific geometry to determine the statistical probability of thrombus particles exiting each major artery. The geometries explored were of a nominal and patient specific nature. Cases of 90% and 0% stenosis at the aortic arch were analyzed, including shunt diameters of 3mm, 3.5mm, and 4mm. Three different placements of the shunt were explored as well. The intent of this study was to suggest best methods of surgical planning in the Hybrid Norwood procedure by providing supporting data for optimal stroke and myocardial infarction prevention.
Show less - Date Issued
- 2017
- Identifier
- CFE0006655, ucf:51232
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006655
- Title
- A Case Study Evaluation of Quality Standards and Online Faculty Development.
- Creator
-
O'Brien, Erin, Gunter, Glenda, Hartshorne, Richard, Thompson, Kelvin, Vitale, Thomas, Haggerty, Dorothy, University of Central Florida
- Abstract / Description
-
This dissertation in practice was designed to provide an evaluation case study of two institutions, one college and one university, in the field of online learning and quality assurance. The writer evaluated these two institutions of higher learning to discover what online teaching criteria are required and what quality assurance processes are being used to assess the quality of the institutions' online courses. An analysis of the data revealed that both institutions were at the appropriate...
Show moreThis dissertation in practice was designed to provide an evaluation case study of two institutions, one college and one university, in the field of online learning and quality assurance. The writer evaluated these two institutions of higher learning to discover what online teaching criteria are required and what quality assurance processes are being used to assess the quality of the institutions' online courses. An analysis of the data revealed that both institutions were at the appropriate stage of development, support, training and quality assurance measures for their sizes, online populations and for the length of time they have been involved in online learning. Findings revealed that both institutions had a quality assurance process in place that is appropriate to their location, population and faculty. There is much to be learned by examining the two different credentialing and quality assurance approaches to online teaching and learning that these two different institutions employ for anyone interested in improving their institutions' processes.
Show less - Date Issued
- 2015
- Identifier
- CFE0005855, ucf:50919
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005855
- Title
- An Anthropological Study of Eating Perspectives, Meal Composition, and Food Choices Among Diverse Student Populations.
- Creator
-
Daws, Chelsea, Matejowsky, Ty, Williams, Lana, Geiger, Vance, University of Central Florida
- Abstract / Description
-
My thesis explores the factors that shape or reinforce international college students' perceptions of food. This research not only examines how cultural values affect individual nutrition and maintenance of eating behaviors, it also addresses the extent to which accessibility impacts eating behaviors. Notably, the research endeavor uses the concept of dietary habitus as an underlying directive mechanism for study. This study finds that most students experience a reduction in their fruit and...
Show moreMy thesis explores the factors that shape or reinforce international college students' perceptions of food. This research not only examines how cultural values affect individual nutrition and maintenance of eating behaviors, it also addresses the extent to which accessibility impacts eating behaviors. Notably, the research endeavor uses the concept of dietary habitus as an underlying directive mechanism for study. This study finds that most students experience a reduction in their fruit and vegetable intake. Another finding suggests that international students eat healthier and are more structured in comparison to domestic students if they hybridize their dietary habitus. Research findings also suggest that most participants perceive food on campus to be both equally healthy and unhealthy, with limited accessibility to national cuisines and affordable healthy foods.
Show less - Date Issued
- 2017
- Identifier
- CFE0006581, ucf:51348
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006581
- Title
- A COUPLED CFD-LUMPED PARAMETER MODEL OF THE HUMAN CIRCULATION: ELUCIDATING THE HEMODYNAMICS OF THE HYBRID NORWOOD PALLIATIVE TREATMENT AND EFFECTS OF THE REVERSE BLALOCK-TAUSSIG SHUNT PLACEMENT AND DIAMETER.
- Creator
-
Ceballos, Andres, Kassab, Alain, Bai, Yuanli, Deng, Weiwei, DeCampli, William, Divo, Eduardo, University of Central Florida
- Abstract / Description
-
The Hybrid Norwood (HN) is a relatively new first stage procedure for neonates with Hypoplastic Left Heart Syndrome (HLHS), in which a sustainable univentricular circulation is established in a less invasive manner than with the standard procedure. A computational multiscale model of such HLHS circulation following the HN procedure was used to obtain detailed hemodynamics. Implementation of a reverse-BT shunt (RBTS), a synthetic bypass from the main pulmonary to the innominate artery placed...
Show moreThe Hybrid Norwood (HN) is a relatively new first stage procedure for neonates with Hypoplastic Left Heart Syndrome (HLHS), in which a sustainable univentricular circulation is established in a less invasive manner than with the standard procedure. A computational multiscale model of such HLHS circulation following the HN procedure was used to obtain detailed hemodynamics. Implementation of a reverse-BT shunt (RBTS), a synthetic bypass from the main pulmonary to the innominate artery placed to counteract aortic arch stenosis, and its effects on local and global hemodynamics were studied.A synthetic and a 3D reconstructed, patient derived anatomy after the HN procedure were utilized, with varying degrees of distal arch obstruction, or stenosis, (nominal and 90% reduction in lumen) and varying RBTS diameters (3.0, 3.5, 4.0 mm). A closed lumped parameter model (LPM) for the peripheral or distal circulation coupled to a 3D Computational Fluid Dynamics (CFD) model that allows detailed description of the local hemodynamics was created for each anatomy. The implementation of the RBTS in any of the chosen diameters under severe stenosis resulted in a restoration of arterial perfusion to near-nominal levels. Shunt flow velocity, vorticity, and overall wall shear stress levels are inverse functions of shunt diameter, while shunt perfusion and systemic oxygen delivery correlates positively with diameter. No correlation of shunt diameter with helicity was recorded.In the setting of the hybrid Norwood circulation, our results suggest: (1) the 4.0mm RBTS may be more thrombogenic when implemented in the absence of severe arch stenosis and (2) the 3.0mm and 3.5mm RBTS may be a more suitable alternative, with preference to the latter since it provides similar hemodynamics at lower levels of wall shear stress.
Show less - Date Issued
- 2015
- Identifier
- CFE0005772, ucf:50068
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005772
- Title
- An Investigation of Online Tools and Teaching, Social, and Cognitive Presence in a Large Hybrid Online Class.
- Creator
-
Rath, Victoria, Gunter, Glenda, Boote, David, Holt, Larry, Hornik, Steven, University of Central Florida
- Abstract / Description
-
The purpose of this research study was to explore the impact of specific Web 2.0 tools on students' experience of teaching, social, and cognitive presence and motivation when enrolled in a very large hybrid course. With online course enrollments continuing to grow at a higher rate than traditional enrollments in higher education (Allen (&) Seaman, 2011) and universities increasing class sizes as a way to meet this demand with fewer fiscal resources, it is imperative to find ways to keep...
Show moreThe purpose of this research study was to explore the impact of specific Web 2.0 tools on students' experience of teaching, social, and cognitive presence and motivation when enrolled in a very large hybrid course. With online course enrollments continuing to grow at a higher rate than traditional enrollments in higher education (Allen (&) Seaman, 2011) and universities increasing class sizes as a way to meet this demand with fewer fiscal resources, it is imperative to find ways to keep students engaged and motivated when enrolled in very large classes. This study used the Community of Inquiry framework (Garrison, Anderson (&) Archer, 2000) to examine the effect of specific Web 2.0 tools (asynchronous discussion, streaming lectures, multimedia lecture demonstrations, Twitter, and the Second Life virtual world) on teaching, social, and cognitive presence and motivation. The sample population for this study (n = 567) consisted of undergraduate students enrolled in a very large hybrid accounting course in the fall of 2010 at the University of Central Florida. The total enrollment for the course was 943 students. Students could attend face-to-face (f2f) class sessions in a large lecture room that seated 285 students or they could view a streaming video capture of the lectures online. Students were not required to attend the f2f class sessions and could complete the course entirely online.Data were analyzed using one-way analysis of variances (ANOVA), and results of the statistical analyses indicated that students who frequently used the Web 2.0 tools had statistically significant higher mean motivation scores than students who did not use the tools as frequently. Additionally, students who frequently attended the f2f sessions had statistically significant higher mean social presence scores compared to students who attended sometimes or not at all. Attending the f2f sessions, however, did not result in higher mean scores of teaching or cognitive presence.When examined for the impact of the specific Web 2.0 tools, analysis of the ANOVA results indicated that students who used the discussion, streaming lectures, multimedia lecture demonstrations, and Twitter all of the time had significantly higher mean scores of teaching, social, and cognitive presence compared to those students who used the tools less frequently. Further research should be conducted on large hybrid and online courses in different content areas and on those that use different types of learning approaches.
Show less - Date Issued
- 2012
- Identifier
- CFE0004638, ucf:49890
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004638
- 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
