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Title: Self-assembly of Amyloid Aggregates Simulated with Molecular Dynamics.
Creator: Berhanu, Workalemahu, Masunov, Artem, Kolpashchikov, Dmitry, Ye, Jingdong, Zou, Shengli, Schulte, Alfons, University of Central Florida
Abstract / Description: ABSTRACTAmyloids are highly ordered cross-? sheet aggregates that are associated with many diseases such as Alzheimer's, type II diabetes and prion diseases. Recently a progress has been made in structure elucidation, environmental effects and thermodynamic properties of amyloid aggregates. However, detailed understanding of how mutation, packing polymorphism and small organic molecules influence amyloid structure and dynamics is still lacking. Atomistic modeling of these phenomena with...
Show moreABSTRACTAmyloids are highly ordered cross-? sheet aggregates that are associated with many diseases such as Alzheimer's, type II diabetes and prion diseases. Recently a progress has been made in structure elucidation, environmental effects and thermodynamic properties of amyloid aggregates. However, detailed understanding of how mutation, packing polymorphism and small organic molecules influence amyloid structure and dynamics is still lacking. Atomistic modeling of these phenomena with molecular dynamics (MD) simulations holds a great promise to bridge this gap. This Thesis describes the results of MD simulations, which provide insight into the effects of mutation, packing polymorphism and molecular inhibitors on amyloid peptides aggregation. Chapter 1 discusses the structure of amyloid peptides, diseases associated with amyloid aggregation, mechanism of aggregation and strategies to treat amyloid diseases. Chapter 2 describes the basic principles of molecular dynamic simulation and methods of trajectory analysis used in the Thesis. Chapter 3 presents the results of the study of several all-atom molecular dynamics simulations with explicit solvent, starting from the crystalline fragments of two to ten monomers each. Three different hexapeptides and their analogs produced with single glycine replacement were investigated to study the structural stability, aggregation behavior and thermodynamics of the amyloid oligomers. Chapter 4 presents multiple molecular dynamics (MD) simulation of a pair polymorphic form of five short segments of amyloid peptide. Chapter 5 describes MD study of single-layer oligomers of the full-length insulin with a goal to identify the structural elements that are important for insulin amyloid stability, and to suggest single glycine mutants that may improve formulation. Chapter 6 presents the investigation of the mechanism of the interaction of polyphenols molecules with the protofibrils formed by an amyloidogenic hexapeptide fragment (VQIVYK) of Tau peptide by molecular dynamics simulations in explicit solvent. We analyzed the trajectories of the large (7(&)#215;4) aggregate with and without the polyphenols.Our MD simulations for both the short and full length amyloids revealed adding strands enhances the internal stability of wildtype aggregates. The degree of structural similarity between the oligomers in simulation and the fibril models constructed based on experimental data may explain why adding oligomers shortens the experimentally observed nucleation lag phase of amyloid aggregation. The MM-PBSA free energy calculation revealed nonpolar components of the free energy is more favorable while electrostatic solvation is unfavorable for the sheet to sheet interaction. This explains the acceleration of aggregation by adding nonpolar co-solvents (methanol, tri?uoroethanol, and hexa?uoroisopropanol). Free energy decomposition shows residues situated at the interface were found to make favorable contribution to the peptide -peptide association.The results from the simulations might provide both the valuable insight for amyloid aggregation as well as assist in inhibitor design efforts. First, the simulation of the single glycine mutants at the steric zipper of the short segments of various pathological peptides indicates the intersheet steric zipper is important for amyloid stability. Mutation of the side chains at the dry steric zipper disrupts the sheet to sheet packing, making the aggregation unstable. Thus, designing new peptidomimetic inhibitors able to prevent the fibril formation based on the steric zipper motif of the oligomers, similar to the ones examined in this study may become a viable therapeutic strategy. The various steric zipper microcrystal structures of short amyloid segments could be used as a template to design aggregation inhibitor that can block growth of the aggregates. Modification of the steric zipper structure (structure based design) with a single amino acid changes, shuffling the sequences, N- methylation of peptide amide bonds to suppress hydrogen bonding ability of NH groups or replacement with D amino acid sequence that interact with the parent steric zipper could be used in computational search for the new inhibitors. Second, the polyphenols were found to interact with performed oligomer through hydrogen bonding and induce conformational change creating an altered aggregate. The conformational change disrupts the intermolecular amyloid contact remodeling the amyloid aggregate. The recently reported microcrystal structure of short segments of amyloid peptides with small organic molecules could serve as a pharamcophore for virtual screening of aggregation inhibitor using combined docking and MD simulation with possible enhancement of lead enrichment. Finally, our MD simulation of short segments of amyloids with steric zipper polymorphism showed the stability depends on both sequence and packing arrangements. The hydrophilic polar GNNQQNY and NNQNTF with interface containing large polar and/or aromatic side chains (Q/N) are more stable than steric zipper interfaces made of small or hydrophobic residues (SSTNVG, VQIVYK, and MVGGVV). The larger sheet to sheet interface of the dry steric zipper through polar Q/N rich side chains was found to holds the sheets together better than non Q/N rich short amyloid segments. The packing polymorphism could influence the structure based design of aggregation inhibitor and a combination of different aggregation inhibitors might be required to bind to various morphologic forms of the amyloid peptides.
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Date Issued: 2011
Identifier: CFE0004088, ucf:49131
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004088

Title: The Effects of Presentation Mode and Pace on Learning Immunology with Computer Simulation: A Cognitive Evaluation of a Multimedia Learning Resource.
Creator: Bradley-Radakovich, Kristy, Kincaid, John, Khaled, Annette, McDaniel, Rudy, Greenwood-Ericksen, Adams, University of Central Florida
Abstract / Description: Multimedia learning tools have the potential to benefit instructors and learners as supplemental learning materials. However, when such tools are designed inappropriately, this can increase cognitive taxation and impede learning, rendering the tools ineffective. Guided by the theoretical underpinnings provided by cognitive load theory and the cognitive theory of multimedia learning, this study sought to empirically evaluate the effectiveness of a multimedia simulation tool aimed at teaching...
Show moreMultimedia learning tools have the potential to benefit instructors and learners as supplemental learning materials. However, when such tools are designed inappropriately, this can increase cognitive taxation and impede learning, rendering the tools ineffective. Guided by the theoretical underpinnings provided by cognitive load theory and the cognitive theory of multimedia learning, this study sought to empirically evaluate the effectiveness of a multimedia simulation tool aimed at teaching immunology to novices in an instructional setting. The instructional mode and pace of the tool were manipulated, the three levels of each variable yielding nine experimental groups. The effects of mode and pace on workload and learning scores were observed. The results of this study did not support the theory-driven hypotheses. No significant learning gains were found between the configuration groups, however overall significant learning gains were subsequently found when disregarding mode and pace configuration. Pace was found to influence workload such that fast pace presentations significantly increased workload ratings and a significant interaction of mode and pace was found for workload ratings. The findings suggest that the learning material was too high in intrinsic load and the working memory of the learners too highly taxed for the benefits of applying the design principles to be observed. Results also illustrate a potential exception to the conditions of the design principles when complex terminology is to be presented. Workload findings interpreted in the context of stress adaptation potentially indicate points at which learners at maximum capacity begin to exhibit performance decrements.
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Date Issued: 2011
Identifier: CFE0004090, ucf:49150
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004090

Title: A Simulation-Based Evaluation Of Efficiency Strategies For A Primary Care Clinic With Unscheduled Visits.
Creator: Bobbie, Afrifah, Karwowski, Waldemar, Thompson, William, Elshennawy, Ahmad, Mikusinski, Piotr, University of Central Florida
Abstract / Description: In the health care industry, there are strategies to remove inefficiencies from the health delivery process called efficiency strategies. This dissertation proposed a simulation model to evaluate the impact of the efficiency strategies on a primary care clinic with unscheduled "walk-in" patient visits. The simulation model captures the complex characteristics of the Orlando Veteran's Affairs Medical Center (VAMC) primary care clinic. This clinic system includes different types of patients,...
Show moreIn the health care industry, there are strategies to remove inefficiencies from the health delivery process called efficiency strategies. This dissertation proposed a simulation model to evaluate the impact of the efficiency strategies on a primary care clinic with unscheduled "walk-in" patient visits. The simulation model captures the complex characteristics of the Orlando Veteran's Affairs Medical Center (VAMC) primary care clinic. This clinic system includes different types of patients, patient paths, and multiple resources that serve them. Added to the problem complexity is the presence of patient no-shows characteristics and unscheduled patient arrivals, a problem which has been until recently, largely neglected. The main objectives of this research were to develop a model that captures the complexities of the Orlando VAMC, evaluate alternative scenarios to work in unscheduled patient visits, and examine the impact of patient flow, appointment scheduling, and capacity management decisions on the performance of the primary care clinic system. The main results show that only a joint policy of appointment scheduling rules and patient flow decisions has a significant impact on the wait time of scheduled patients. It is recommended that in the future the clinic addresses the problem of serving additional walk-in patients from an integrated scheduling and patient flow viewpoint.
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Date Issued: 2016
Identifier: CFE0006443, ucf:51462
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006443

Title: LDMOS Power Transistor Design and Evaluation using 2D and 3D Device Simulation.
Creator: Salih, Aiman, Yuan, Jiann-Shiun, Sundaram, Kalpathy, Kapoor, Vikram, University of Central Florida
Abstract / Description: The benefit of the super-junction (SJ) technique and the use of a floating P layer for low voltage (30 V) laterally double-diffused metal oxide semiconductor (LDMOS) transistors are investigated in this thesis using Sentaurus TCAD simulation software. Optimizations to the SJ LDMOS were attempted such as adding a buffer layer to the device, but simulation and theoretical evidence point out that the benefits of the SJ technique are marginal at the 30 V application. A replacement for the SJ...
Show moreThe benefit of the super-junction (SJ) technique and the use of a floating P layer for low voltage (30 V) laterally double-diffused metal oxide semiconductor (LDMOS) transistors are investigated in this thesis using Sentaurus TCAD simulation software. Optimizations to the SJ LDMOS were attempted such as adding a buffer layer to the device, but simulation and theoretical evidence point out that the benefits of the SJ technique are marginal at the 30 V application. A replacement for the SJ technique was sought, the floating P structure proved to be a good solution at the low voltage range due to its simpler cost effective process and performance gains achieved with optimization. A new idea of combining the floating P layer with shallow trench isolation is simulated yielding a low figure of merit (on state resistance (&)#215; gate charge) of 5.93 m?-nC.
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Date Issued: 2017
Identifier: CFE0006955, ucf:51673
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006955

Title: Designing a Virtual Embedded Scenario-Based Military Simulation Training Program using Educational and Design Instructional Strategies.
Creator: Cook, Christina, Hopp, Carolyn, Gunter, Glenda, Hewitt, Randall, Vitale, Thomas, University of Central Florida
Abstract / Description: The purpose of this dissertation in practice was to develop and implement a new training program for designers of military intelligence simulation scenarios used to train soldiers. The use of education and design instructional strategies assisted in the ability for designers to gain mastery skills in creating realistic, high-fidelity scenarios that are applied in the training process. The use of simulation scenarios to train adult learners has increased significantly with improvements in...
Show moreThe purpose of this dissertation in practice was to develop and implement a new training program for designers of military intelligence simulation scenarios used to train soldiers. The use of education and design instructional strategies assisted in the ability for designers to gain mastery skills in creating realistic, high-fidelity scenarios that are applied in the training process. The use of simulation scenarios to train adult learners has increased significantly with improvements in technology and its fidelity to engage learners in a realistic way. Despite these advances, the lack of effective design, implementation and analysis of military simulation training programs in the military intelligence community has led to a decrease in simulation utilization, as in the case of the organization examined in this problem of practice. The current training program's increasing difficulties with consistent use by military intelligence simulation scenario designers were discovered in the results of a gap analysis conducted in 2014, prompting this design. This simulation design aimed to examine: (1) a research-based design methodology to match training requirements for the designers, (2) formative assessment of performance and (3) a research-based evaluation framework to determine the effectiveness of the new training program. For the organization's training program, a Simulation-Based Embedded Training (SBET) solution using scenarios was conceived based on research grounded in cognitive theory and instructional design considerations for simulations. As a structured framework for how to design and implement an effective and sustained training program, the educational instructional design model, ADDIE, was used. This model allowed for continual flexibility in each phase to evaluate and implement changes iteratively. The instructional model and its techniques were used with fidelity, specifically for training the designers of the simulation system. Industries will continue to increase the use of simulation as advances in technologies offer more realistic, safe, and complex training environments.A detailed strategy was provided specific to the organization using a research-based instructional approach integrated into program requirements set forth by the government. This proposed solution, supported by research in the application of instructional strategies, is specific to this organization; however, the training program design differs from other high-fidelity military simulator training programs through its use of dispersed training to the simulation scenario designers using realistic scenarios to mimic the tasks that the designers themselves must create. The difference in the solution in this dissertation in practice is: 1) that the simulation scenarios are designed without the help of subject matter experts by using the embedded instructional strategies and 2) the design is to the fidelity of realism required for military intelligence training exercises.
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Date Issued: 2018
Identifier: CFE0006990, ucf:51617
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006990

Title: A Simulation-Based Task Analysis using Agent-Based, Discrete Event and System Dynamics simulation.
Creator: Angelopoulou, Anastasia, Karwowski, Waldemar, Kincaid, John, Xanthopoulos, Petros, Hancock, Peter, University of Central Florida
Abstract / Description: Recent advances in technology have increased the need for using simulation models to analyze tasks and obtain human performance data. A variety of task analysis approaches and tools have been proposed and developed over the years. Over 100 task analysis methods have been reported in the literature. However, most of the developed methods and tools allow for representation of the static aspects of the tasks performed by expert system-driven human operators, neglecting aspects of the work...
Show moreRecent advances in technology have increased the need for using simulation models to analyze tasks and obtain human performance data. A variety of task analysis approaches and tools have been proposed and developed over the years. Over 100 task analysis methods have been reported in the literature. However, most of the developed methods and tools allow for representation of the static aspects of the tasks performed by expert system-driven human operators, neglecting aspects of the work environment, i.e. physical layout, and dynamic aspects of the task. The use of simulation can help face the new challenges in the field of task analysis as it allows for simulation of the dynamic aspects of the tasks, the humans performing them, and their locations in the environment. Modeling and/or simulation task analysis tools and techniques have been proven to be effective in task analysis, workload, and human reliability assessment. However, most of the existing task analysis simulation models and tools lack features that allow for consideration of errors, workload, level of operator's expertise and skills, among others. In addition, the current task analysis simulation tools require basic training on the tool to allow for modeling the flow of task analysis process and/or error and workload assessment. The modeling process is usually achieved using drag and drop functionality and, in some cases, programming skills.This research focuses on automating the modeling process and simulating individuals (or groups of individuals) performing tasks in a dynamic work environment in any domain. The main objective of this research is to develop a universal tool that allows for modeling and simulation of task analysis models in a short amount of time with limited need for training or knowledge of modeling and simulation theory. A Universal Task Analysis Simulation Modeling (UTASiMo) tool can be used for automatically generating simulation models that analyze the tasks performed by human operators. UTASiMo is a multi-method modeling and simulation tool developed as a combination of agent-based, discrete event, and system dynamics simulation models. A generic multi-method modeling and simulation framework, named 3M(&)S Framework, as well as the Unified Modeling Language have been used for the design of the conceptual model and the implementation of the simulation tool. UTASiMo-generated models are dynamically created during run-time based on user inputs. The simulation results include estimations of operator workload, task completion time, and probability of human errors based on human operator variability and task structure.
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Date Issued: 2015
Identifier: CFE0006252, ucf:51040
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006252

Title: MODELING, DESIGN AND EVALUATION OF NETWORKING SYSTEMS AND PROTOCOLS THROUGH SIMULATION.
Creator: Lacks, Daniel, Kocak, Taskin, University of Central Florida
Abstract / Description: Computer modeling and simulation is a practical way to design and test a system without actually having to build it. Simulation has many benefits which apply to many different domains: it reduces costs creating different prototypes for mechanical engineers, increases the safety of chemical engineers exposed to dangerous chemicals, speeds up the time to model physical reactions, and trains soldiers to prepare for battle. The motivation behind this work is to build a common software framework...
Show moreComputer modeling and simulation is a practical way to design and test a system without actually having to build it. Simulation has many benefits which apply to many different domains: it reduces costs creating different prototypes for mechanical engineers, increases the safety of chemical engineers exposed to dangerous chemicals, speeds up the time to model physical reactions, and trains soldiers to prepare for battle. The motivation behind this work is to build a common software framework that can be used to create new networking simulators on top of an HLA-based federation for distributed simulation. The goals are to model and simulate networking architectures and protocols by developing a common underlying simulation infrastructure and to reduce the time a developer has to learn the semantics of message passing and time management to free more time for experimentation and data collection and reporting. This is accomplished by evolving the simulation engine through three different applications that model three different types of network protocols. Computer networking is a good candidate for simulation because of the Internet's rapid growth that has spawned off the need for new protocols and algorithms and the desire for a common infrastructure to model these protocols and algorithms. One simulation, the 3DInterconnect simulator, simulates data transmitting through a hardware k-array n-cube network interconnect. Performance results show that k-array n-cube topologies can sustain higher traffic load than the currently used interconnects. The second simulator, Cluster Leader Logic Algorithm Simulator, simulates an ad-hoc wireless routing protocol that uses a data distribution methodology based on the GPS-QHRA routing protocol. CLL algorithm can realize a maximum of 45% power savings and maximum 25% reduced queuing delay compared to GPS-QHRA. The third simulator simulates a grid resource discovery protocol for helping Virtual Organizations to find resource on a grid network to compute or store data on. Results show that worst-case 99.43% of the discovery messages are able to find a resource provider to use for computation. The simulation engine was then built to perform basic HLA operations. Results show successful HLA functions including creating, joining, and resigning from a federation, time management, and event publication and subscription.
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Date Issued: 2007
Identifier: CFE0001887, ucf:47399
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001887

Title: AN INTERACTIVE DISTRIBUTED SIMULATION FRAMEWORK WITH APPLICATION TO WIRELESS NETWORKS AND INTRUSION DETECTION.
Creator: Kachirski, Oleg, Guha, Ratan, University of Central Florida
Abstract / Description: In this dissertation, we describe the portable, open-source distributed simulation framework (WINDS) targeting simulations of wireless network infrastructures that we have developed. We present the simulation framework which uses modular architecture and apply the framework to studies of mobility pattern effects, routing and intrusion detection mechanisms in simulations of large-scale wireless ad hoc, infrastructure, and totally mobile networks. The distributed simulations within the...
Show moreIn this dissertation, we describe the portable, open-source distributed simulation framework (WINDS) targeting simulations of wireless network infrastructures that we have developed. We present the simulation framework which uses modular architecture and apply the framework to studies of mobility pattern effects, routing and intrusion detection mechanisms in simulations of large-scale wireless ad hoc, infrastructure, and totally mobile networks. The distributed simulations within the framework execute seamlessly and transparently to the user on a symmetric multiprocessor cluster computer or a network of computers with no modifications to the code or user objects. A visual graphical interface precisely depicts simulation object states and interactions throughout the simulation execution, giving the user full control over the simulation in real time. The network configuration is detected by the framework, and communication latency is taken into consideration when dynamically adjusting the simulation clock, allowing the simulation to run on a heterogeneous computing system. The simulation framework is easily extensible to multi-cluster systems and computing grids. An entire simulation system can be constructed in a short time, utilizing user-created and supplied simulation components, including mobile nodes, base stations, routing algorithms, traffic patterns and other objects. These objects are automatically compiled and loaded by the simulation system, and are available for dynamic simulation injection at runtime. Using our distributed simulation framework, we have studied modern intrusion detection systems (IDS) and assessed applicability of existing intrusion detection techniques to wireless networks. We have developed a mobile agent-based IDS targeting mobile wireless networks, and introduced load-balancing optimizations aimed at limited-resource systems to improve intrusion detection performance. Packet-based monitoring agents of our IDS employ a CASE-based reasoner engine that performs fast lookups of network packets in the existing SNORT-based intrusion rule-set. Experiments were performed using the intrusion data from MIT Lincoln Laboratories studies, and executed on a cluster computer utilizing our distributed simulation system.
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Date Issued: 2005
Identifier: CFE0000642, ucf:46545
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000642

Title: MONTE CARLO SIMULATION OF HOLE TRANSPORT AND TERAHERTZ AMPLIFICATION IN MULTILAYER DELTA DOPED SEMICONDUCTOR STRUCTURES.
Creator: Dolguikh, Maxim, Peale, Robert, University of Central Florida
Abstract / Description: Monte Carlo method for the simulation of hole dynamics in degenerate valence subbands of cubic semiconductors is developed. All possible intra- and inter-subband scattering rates are theoretically calculated for Ge, Si, and GaAs. A far-infrared laser concept based on intersubband transitions of holes in p-type periodically delta-doped semiconductor films is studied using numerical Monte-Carlo simulation of hot hole dynamics. The considered device consists of monocrystalline pure Ge layers...
Show moreMonte Carlo method for the simulation of hole dynamics in degenerate valence subbands of cubic semiconductors is developed. All possible intra- and inter-subband scattering rates are theoretically calculated for Ge, Si, and GaAs. A far-infrared laser concept based on intersubband transitions of holes in p-type periodically delta-doped semiconductor films is studied using numerical Monte-Carlo simulation of hot hole dynamics. The considered device consists of monocrystalline pure Ge layers periodically interleaved with delta-doped layers and operates with vertical or in-plane hole transport in the presence of a perpendicular in-plane magnetic field. Inversion population on intersubband transitions arises due to light hole accumulation in E B fields, as in the bulk p-Ge laser. However, the considered structure achieves spatial separation of hole accumulation regions from the doped layers, which reduces ionized-impurity and carrier-carrier scattering for the majority of light holes. This allows remarkable increase of the gain in comparison with bulk p-Ge lasers. Population inversion and gain sufficient for laser operation are expected up to 77 K. Test structures grown by chemical vapor deposition demonstrate feasibility of producing the device with sufficient active thickness to allow quasioptical electrodynamic cavity solutions. The same device structure is considered in GaAs. The case of Si is much more complicated due to strong anisotropy of the valence band. The primary new result for Si is the first consideration of the anisotropy of optical phonon scattering for hot holes.
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Date Issued: 2005
Identifier: CFE0000863, ucf:46672
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000863

Title: THEORETICAL TAILORING OF PERFORATED THIN SILVER FILMS FOR AFFINITY SURFACE PLASMON RESONANCE BIOSENSOR APPLICATIONS.
Creator: Gongora Jr., Renan, Zou, Shengli, University of Central Florida
Abstract / Description: Metallic films, in conjunction with biochemical-targeted probes, are expected to provide early diagnosis, targeted therapy and non-invasive monitoring for epidemiology applications. The resonance wavelength peaks, both plasmonic and Wood-Rayleigh Anomalies (WRAs), in the scattering spectra are affected by the metallic architecture. As of today, much research has been devoted to extinction efficiency in the plasmonic region. However, Wood Rayleigh Anomalies (WRAs) typically occur at...
Show moreMetallic films, in conjunction with biochemical-targeted probes, are expected to provide early diagnosis, targeted therapy and non-invasive monitoring for epidemiology applications. The resonance wavelength peaks, both plasmonic and Wood-Rayleigh Anomalies (WRAs), in the scattering spectra are affected by the metallic architecture. As of today, much research has been devoted to extinction efficiency in the plasmonic region. However, Wood Rayleigh Anomalies (WRAs) typically occur at wavelengths associated with the periodic distance of the structures. A significant number of papers have already focused on the plasmonic region of the visible spectrum, but a less explored area of research was presented here; the desired resonance wavelength region was 400-500nm, corresponding to the WRA for the silver film with perforated hole with a periodic distance of 400nm. Simulations obtained from the discrete dipole approximation (DDA) method, show sharp spectral bands (either high or low scattering efficiencies) in both wavelength regions of the visible spectrum simulated from Ag film with cylindrical hole arrays In addition, surprising results were obtained in the parallel scattering spectra,where the electric field is contained in the XY plane, when the angle between the metallic surface and the incident light was adjusted to 14 degrees; a bathochromic shift was observed for the WRA peak suggesting a hybrid resonance mode. Metallic films have the potential to be used in instrumental techniques for use as sensors, i.e. surface plasmon resonance affinity biosensors, but are not limited to such instrumental techniques. Although the research here was aimed towards affinity biosensors, other sensory designs can benefit from the optimized Ag film motifs. The intent of the study was to elucidate metal film motifs, when incorporated into instrumental analysis, allowing the quantification of genetic material in the visible region. Any research group that routinely benefits from quantification of various analytes in solution matrices will also benefit from this study, as there are a bewildering number of instrumental sensory methods and setups available.
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Date Issued: 2014
Identifier: CFH0004538, ucf:45155
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0004538

Title: Eye Movements and Spatial Ability: Influences on Thinking During Analogical Problem Solving.
Creator: Schroeder, Bradford, Sims, Valerie, Szalma, James, Neider, Mark, Gill, Michele, University of Central Florida
Abstract / Description: Classic studies have examined the factors that influence the way in which people can solve difficult (")insight(") problems, which require creative solutions. Recent research has shown that guiding one's eye movements in a pattern spatially congruent with the solution improves the likelihood of formulating a spatial solution. The authors in this line of research argued that guiding eye movements in a pattern spatially equivalent to the solution of the problem yields an embodied cognitive...
Show moreClassic studies have examined the factors that influence the way in which people can solve difficult (")insight(") problems, which require creative solutions. Recent research has shown that guiding one's eye movements in a pattern spatially congruent with the solution improves the likelihood of formulating a spatial solution. The authors in this line of research argued that guiding eye movements in a pattern spatially equivalent to the solution of the problem yields an embodied cognitive benefit that aids problem solving. Specifically, guiding eye movements leads to the generation of a mental representation containing perceptual information that helps a problem solver mentally simulate the problem features, increasing likelihood to generate a solution to the problem. However, evidence from a small but critically relevant area of research supports that this embodied effect may be more simply a creativity-priming effect. The proposed research aimed to disentangle these ideas while addressing other research questions of interest: do embodied problem solving benefits transfer to later problem solving? Do individual differences in spatial ability influence how people solve these problems? The present study combined previously established methodologies in problem solving and analogical problem solving to investigate these research questions. Results of the present work tentatively support the embodied priming effect, mediated by a creativity-priming effect that influences problem solving performance. Both effects emerged after manipulating problem solvers' eye movements. There is also modest support for a link between spatial ability and analogical problem solving, but not initial problem solving. These results are interpreted through the lens of embodied cognitive theory, providing tentative support that guiding eye movements can influence reasoning through an enhancement of creativity.
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Date Issued: 2018
Identifier: CFE0007366, ucf:52079
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007366

Title: The Identification and Segmentation of Astrocytoma Prior to Critical Mass, by means of a Volumetric/Subregion Regression Analysis of Normal and Neoplastic Brain Tissue.
Creator: Higgins, Lyn, Hughes, Charles, Morrow, Patricia Bockelman, Bagci, Ulas, Lisle, Curtis, University of Central Florida
Abstract / Description: As the underlying cause of Glioblastoma Multiforme (GBM) is presently unclear, this research implements a new approach to identifying and segmenting plausible instances of GBM prior to critical mass. Grade-IV Astrocytoma, or GBM, is an aggressive and malignant cancer arising from star-shaped glial cells, or astrocytes, where the astrocytes, functionally, assist in the support and protection of neurons within the central nervous system and spinal cord. Subsequently, our motivation for...
Show moreAs the underlying cause of Glioblastoma Multiforme (GBM) is presently unclear, this research implements a new approach to identifying and segmenting plausible instances of GBM prior to critical mass. Grade-IV Astrocytoma, or GBM, is an aggressive and malignant cancer arising from star-shaped glial cells, or astrocytes, where the astrocytes, functionally, assist in the support and protection of neurons within the central nervous system and spinal cord. Subsequently, our motivation for researching the ability to recognize GBM is that the underlying cause of the mutation is presently unclear, leading to the operative that GBM is only detectable through a combination of MRI and CT brain scans, cooperatively, along with a resection biopsy. Since astrocytoma only becomes evident at critical mass, when the cellular structure of the neoplasm becomes visible within the image, this research seeks to achieve earlier identification and segmentation of the neoplasm by evaluating the malignant area via a volumetric voxel approach to removing noise artifacts and analyzing voxel differentials. In order to investigate neoplasm continuity, a differential approach has been implemented utilizing a multi-polynomial/multi-domain regression algorithm, thus, ultimately, providing a graphical and mathematical analysis of the differentials within critical mass and non-critical mass images. Given these augmentations to MRI and CT image rectifications, we theorize that our approach will improve on astrocytoma recognition and segmentation, along with achieving greater accuracy in diagnostic evaluations of the malignant area.
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Date Issued: 2018
Identifier: CFE0007336, ucf:52111
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007336

Title: Real-time SIL Emulation Architecture for Cooperative Automated Vehicles.
Creator: Gupta, Nitish, Pourmohammadi Fallah, Yaser, Rahnavard, Nazanin, Vosoughi, Azadeh, University of Central Florida
Abstract / Description: This thesis presents a robust, flexible and real-time architecture for Software-in-the-Loop (SIL) testing of connected vehicle safety applications. Emerging connected and automated vehicles (CAV) use sensing, communication and computing technologies in the design of a host of new safety applications. Testing and verification of these applications is a major concern for the automotive industry. The CAV safety applications work by sharing their state and movement information over wireless...
Show moreThis thesis presents a robust, flexible and real-time architecture for Software-in-the-Loop (SIL) testing of connected vehicle safety applications. Emerging connected and automated vehicles (CAV) use sensing, communication and computing technologies in the design of a host of new safety applications. Testing and verification of these applications is a major concern for the automotive industry. The CAV safety applications work by sharing their state and movement information over wireless communication links. Vehicular communication has fueled the development of various Cooperative Vehicle Safety (CVS) applications. Development of safety applications for CAV requires testing in many different scenarios. However, the recreation of test scenarios for evaluating safety applications is a very challenging task. This is mainly due to the randomness in communication, difficulty in recreating vehicle movements precisely, and safety concerns for certain scenarios. We propose to develop a standalone Remote Vehicle Emulator (RVE) that can reproduce V2V messages of remote vehicles from simulations or from previous tests, while also emulating the over the air behavior of multiple communicating nodes. This is expected to significantly accelerate the development cycle. RVE is a unique and easily configurable emulation cum simulation setup to allow Software in the Loop (SIL) testing of connected vehicle applications in a realistic and safe manner. It will help in tailoring numerous test scenarios, expediting algorithm development and validation as well as increase the probability of finding failure modes. This, in turn, will help improve the quality of safety applications while saving testing time and reducing cost.The RVE architecture consists of two modules, the Mobility Generator, and the Communication emulator. Both of these modules consist of a sequence of events that are handled based on the type of testing to be carried out. The communication emulator simulates the behavior of MAC layer while also considering the channel model to increase the probability of successful transmission. It then produces over the air messages that resemble the output of multiple nodes transmitting, including corrupted messages due to collisions. The algorithm that goes inside the emulator has been optimized so as to minimize the communication latency and make this a realistic and real-time safety testing tool. Finally, we provide a multi-metric experimental evaluation wherein we verified the simulation results with an identically configured ns3 simulator. With the aim to improve the quality of testing of CVS applications, this unique architecture would serve as a fundamental design for the future of CVS application testing.
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Date Issued: 2018
Identifier: CFE0007185, ucf:52280
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007185

Title: Experimental study and modeling of mechanical micro-machining of particle reinforced heterogeneous materials.
Creator: Liu, Jian, Xu, Chengying, An, Linan, Gordon, Ali, Bai, Yuanli, Gong, Xun, University of Central Florida
Abstract / Description: This study focuses on developing explicit analytical and numerical process models for mechanical micro-machining of heterogeneous materials. These models are used to select suitable process parameters for preparing and micro-machining of these advanced materials. The material system studied in this research is Magnesium Metal Matrix Composites (Mg-MMCs) reinforced with nano-sized and micro-sized silicon carbide (SiC) particles.This research is motivated by increasing demands of miniaturized...
Show moreThis study focuses on developing explicit analytical and numerical process models for mechanical micro-machining of heterogeneous materials. These models are used to select suitable process parameters for preparing and micro-machining of these advanced materials. The material system studied in this research is Magnesium Metal Matrix Composites (Mg-MMCs) reinforced with nano-sized and micro-sized silicon carbide (SiC) particles.This research is motivated by increasing demands of miniaturized components with high mechanical performance in various industries. Mg-MMCs become one of the best candidates due to its light weight, high strength, and high creep/wear resistance. However, the improved strength and abrasive nature of the reinforcements bring great challenges for the subsequent micro-machining process.Systematic experimental investigations on the machinability of Mg-MMCs reinforced with SiC nano-particles have been conducted. The nanocomposites containing 5 Vol.%, 10 Vol.% and 15 Vol.% reinforcements, as well as pure magnesium, are studied by using the Design of Experiment (DOE) method. Cutting forces, surface morphology and surface roughness are characterized to understand the machinability of the four materials. Based on response surface methodology (RSM) design, experimental models and related contour plots have been developed to build a connection between different materials properties and cutting parameters. Those models can be used to predict the cutting force, the surface roughness, and then optimize the machining process.An analytical cutting force model has been developed to predict cutting forces of Mg-MMCs reinforced with nano-sized SiC particles in the micro-milling process. This model is different from previous ones by encompassing the behaviors of reinforcement nanoparticles in three cutting scenarios, i.e., shearing, ploughing and elastic recovery. By using the enhanced yield strength in the cutting force model, three major strengthening factors are incorporated, including load-bearing effect, enhanced dislocation density strengthening effect and Orowan strengthening effect. In this way, the particle size and volume fraction, as significant factors affecting the cutting forces, are explicitly considered. In order to validate the model, various cutting conditions using different size end mills (100 (&)#181;m and 1 mm dia.) have been conducted on Mg-MMCs with volume fraction from 0 (pure magnesium) to 15 Vol.%. The simulated cutting forces show a good agreement with the experimental data. The proposed model can predict the major force amplitude variations and force profile changes as functions of the nanoparticles' volume fraction. Next, a systematic evaluation of six ductile fracture models has been conducted to identify the most suitable fracture criterion for micro-scale cutting simulations. The evaluated fracture models include constant fracture strain, Johnson-Cook, Johnson-Cook coupling criterion, Wilkins, modified Cockcroft-Latham, and Bao-Wierzbicki fracture criterion. By means of a user material subroutine (VUMAT), these fracture models are implemented into a Finite Element (FE) orthogonal cutting model in ABAQUS/Explicit platform. The local parameters (stress, strain, fracture factor, velocity fields) and global variables (chip morphology, cutting forces, temperature, shear angle, and machined surface integrity) are evaluated. Results indicate that by coupling with the damage evolution, the capability of Johnson-Cook and Bao-Wierzbicki can be further extended to predict accurate chip morphology. Bao-Wierzbiki-based coupling model provides the best simulation results in this study. The micro-cutting performance of MMCs materials has also been studied by using FE modeling method. A 2-D FE micro-cutting model has been constructed. Firstly, homogenized material properties are employed to evaluate the effect of particles' volume fraction. Secondly, micro-structures of the two-phase material are modeled in FE cutting models. The effects of the existing micro-sized and nano-sized ceramic particles on micro-cutting performance are carefully evaluated in two case studies. Results show that by using the homogenized material properties based on Johnson-Cook plasticity and fracture model with damage evolution, the micro-cutting performance of nano-reinforced Mg-MMCs can be predicted. Crack generation for SiC particle reinforced MMCs is different from their homogeneous counterparts; the effect of micro-sized particles is different from the one of nano-sized particles.In summary, through this research, a better understanding of the unique cutting mechanism for particle reinforced heterogeneous materials has been obtained. The effect of reinforcements on micro-cutting performance is obtained, which will help material engineers tailor suitable material properties for special mechanical design, associated manufacturing method and application needs. Moreover, the proposed analytical and numerical models provide a guideline to optimize process parameters for preparing and micro-machining of heterogeneous MMCs materials. This will eventually facilitate the automation of MMCs' machining process and realize high-efficiency, high-quality, and low-cost manufacturing of composite materials.
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Date Issued: 2012
Identifier: CFE0004570, ucf:49196
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004570

Title: Numerical Simulation of Electrolyte-Supported Planar Button Solid Oxide Fuel Cell.
Creator: Aman, Amjad, Orlovskaya, Nina, Xu, Yunjun, Das, Tuhin, University of Central Florida
Abstract / Description: Solid Oxide Fuel Cells are fuel cells that operate at high temperatures usually in the range of 600oC to 1000oC and employ solid ceramics as the electrolyte. In Solid Oxide Fuel Cells oxygen ions (O2-) are the ionic charge carriers. Solid Oxide Fuel Cells are known for their higher electrical efficiency of about 50-60% [1] compared to other types of fuel cells and are considered very suitable in stationary power generation applications. It is very important to study the effects of different...
Show moreSolid Oxide Fuel Cells are fuel cells that operate at high temperatures usually in the range of 600oC to 1000oC and employ solid ceramics as the electrolyte. In Solid Oxide Fuel Cells oxygen ions (O2-) are the ionic charge carriers. Solid Oxide Fuel Cells are known for their higher electrical efficiency of about 50-60% [1] compared to other types of fuel cells and are considered very suitable in stationary power generation applications. It is very important to study the effects of different parameters on the performance of Solid Oxide Fuel Cells and for this purpose the experimental or numerical simulation method can be adopted as the research method of choice. Numerical simulation involves constructing a mathematical model of the Solid Oxide Fuel Cell and use of specifically designed software programs that allows the user to manipulate the model to evaluate the system performance under various configurations and in real time. A model is only usable when it is validated with experimental results. Once it is validated, numerical simulation can give accurate, consistent and efficient results. Modeling allows testing and development of new materials, fuels, geometries, operating conditions without disrupting the existing system configuration. In addition, it is possible to measure internal variables which are experimentally difficult or impossible to measure and study the effects of different operating parameters on power generated, efficiency, current density, maximum temperatures reached, stresses caused by temperature gradients and effects of thermal expansion for electrolytes, electrodes and interconnects.Since Solid Oxide Fuel Cell simulation involves a large number of parameters and complicated equations, mostly Partial Differential Equations, the situation calls for a sophisticated simulation technique and hence a Finite Element Method (FEM) multiphysics approach will be employed. This can provide three-dimensional localized information inside the fuel cell. For this thesis, COMSOL Multiphysics(&)#174; version 4.2a will be used for simulation purposes because it has a Batteries (&) Fuel Cells module, the ability to incorporate custom Partial Differential Equations and the ability to integrate with and utilize the capabilities of other tools like MATLAB(&)#174;, Pro/Engineer(&)#174;, SolidWorks(&)#174;. Fuel Cells can be modeled at the system or stack or cell or the electrode level. This thesis will study Solid Oxide Fuel Cell modeling at the cell level. Once the model can be validated against experimental data for the cell level, then modeling at higher levels can be accomplished in the future. Here the research focus is on Solid Oxide Fuel Cells that use hydrogen as the fuel. The study focuses on solid oxide fuel cells that use 3-layered, 4-layered and 6-layered electrolytes using pure YSZ or pure SCSZ or a combination of layers of YSZ and SCSZ. A major part of this research will be to compare SOFC performance of the different configurations of these electrolytes. The cathode and anode material used are (La0.6Sr0.4)0.95-0.99Co0.2Fe0.8O3 and Ni-YSZ respectively.
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Date Issued: 2012
Identifier: CFE0004349, ucf:49431
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004349

Title: COMPUTER TECHNOLOGYIN THE DESIGN PROCESS.
Creator: Montague, Gregory, Scott, Bert, University of Central Florida
Abstract / Description: This is a study of computer technologyÃ‚Â's impact on the theatrical design process. The tools of communication provided by technology were studied, and an analysis was conducted in the classroom of Digital Rendering, Digital Rendering Videos, and 3d CADD. After-wards, these tools were applied to an actual production of West Side Story where, with the addition of 3d light simulation software, the tools were used to communicate the design ideas from the lighting designer...
Show moreThis is a study of computer technologyÃ‚Â's impact on the theatrical design process. The tools of communication provided by technology were studied, and an analysis was conducted in the classroom of Digital Rendering, Digital Rendering Videos, and 3d CADD. After-wards, these tools were applied to an actual production of West Side Story where, with the addition of 3d light simulation software, the tools were used to communicate the design ideas from the lighting designer to the director. The goal of this process was to provide a Ã‚Â"real to lifeÃ‚Â" virtual representation of the show to the director with the least amount of confusion. An additional goal was to test the limits and functions of the software; trying to learn all the benefits that could be provided to the process of mounting a theatrical production.
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Date Issued: 2010
Identifier: CFE0003032, ucf:48365
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003032

Title: A New Methodology for Evaluating the Effectiveness of Bus Rapid Transit Strategies.
Creator: Alomari, Ahmad, Al-Deek, Haitham, Eluru, Naveen, Tatari, Omer, Maboudou, Edgard, University of Central Florida
Abstract / Description: Over the last few years, public transportation has become more desirable as capacity of existing roadways failed to keep up with rapidly increasing traffic demand. Buses are one of the most common modes of public transportation with low impact on network capacity, especially in small and congested urban areas. However, the use of regularly scheduled buses as the main public transport mode can become useless with the presence of traffic congestion and dense construction areas. In cases like...
Show moreOver the last few years, public transportation has become more desirable as capacity of existing roadways failed to keep up with rapidly increasing traffic demand. Buses are one of the most common modes of public transportation with low impact on network capacity, especially in small and congested urban areas. However, the use of regularly scheduled buses as the main public transport mode can become useless with the presence of traffic congestion and dense construction areas. In cases like these, innovative solutions, such as bus rapid transit (BRT), can provide an increased level of service without having to resort to other, more expensive modes, such as light rail transit (LRT) and metro systems (subways). Transit signal priority (TSP), which provides priority to approaching buses at signalized intersections by extending the green or truncating the red, can also increase the performance of the bus service.Understanding the combined impact of TSP and BRT on network traffic operations can be complex. Although TSP has been implemented worldwide, none of the previous studies have examined in depth the effects of using conditional and unconditional TSP strategies with a BRT system. The objective of this research is to evaluate the effectiveness of BRT without TSP, then with conditional or unconditional TSP strategies. The micro-simulation software VISSIM was used to compare different TSP and BRT scenarios. These simulation scenarios include the base scenario (before implementation of the TSP and BRT systems), Unconditional TSP (TSP activates for all buses), Conditional TSP 3 minutes behind (TSP only activates for buses that are 3 minutes or more behind schedule), Conditional TSP 5 minutes behind (only activates for buses 5 minutes or more behind schedule), BRT with no TSP, BRT with Unconditional TSP, BRT with Conditional TSP 3 minutes behind, and BRT with Conditional TSP 5 minutes behind.The VISSIM simulation model was developed, calibrated and validated using a variety of data that was collected in the field. These data included geometric data, (number of lanes, intersection geometries, etc.); traffic data (average daily traffic volumes at major intersections, turning movement percentages at intersections, heavy vehicle percentages, bus passenger data, etc.); and traffic control data (signal types, timings and phasings, split history, etc.). Using this field data ensured the simulation model was sufficient for modeling the test corridor. From this model, the main performance parameters (for all vehicles and for buses only) for through movements in both directions (eastbound and westbound) along the corridor were analyzed for the various BRT/TSP scenarios. These parameters included average travel times, average speed profiles, average delays, and average number of stops. As part of a holistic approach, the effects of BRT and TSP on crossing street delay were also evaluated. Simulation results showed that TSP and BRT scenarios were effective in reducing travel times (up to 26 %) and delays (up to 64%), as well as increasing the speed (up to 47%), compared to the base scenario. The most effective scenarios were achieved by combining BRT and TSP. Results also showed that BRT with Conditional TSP 3 minutes behind significantly improved travel times (17 (-) 26%), average speed (30 (-) 39%), and average total delay per vehicle (11 (-) 32%) for the main corridor through movements compared with the base scenario, with only minor effects on crossing street delays. BRT with Unconditional TSP resulted in significant crossing street delays, especially at major intersections with high traffic demand, which indicates that this scenario is impractical for implementation in the corridor. Additionally, BRT with Conditional TSP 3 minutes behind had better travel time savings than BRT with Conditional TSP 5 minutes behind for both travel directions, making this the most beneficial scenario.This research provided an innovative approach by using nested sets (hierarchical design) of TSP and BRT combination scenarios. Coupled with microscopic simulation, nested sets in the hierarchical design are used to evaluate the effectiveness of BRT without TSP, then with conditional or unconditional TSP strategies. The robust methodology developed in this research can be applied to any corridor to understand the combined TSP and BRT effects on traffic performance. Presenting the results in an organized fashion like this can be helpful in decision making. This research investigated the effects of BRT along I-Drive corridor (before and after conditions) at the intersection level. Intersection analysis demonstrated based on real life data for the before and after the construction of BRT using the Highway Capacity SoftwareTM (HCS2010) that was built based on the Highway Capacity Manual (HCM 2010) procedures for urban streets and signalized intersections. The performance measure used in this analysis is the level of service (LOS) criteria which depends on the control delay (seconds per vehicle) for each approach and for the entire intersection. The results show that implementing BRT did not change the LOS. However, the control delay has improved at most of the intersections' approaches. The majority of intersections operated with an overall LOS "C" or better except for Kirkman Road intersection (T2) with LOS "E" because it has the highest traffic volumes before and after BRT construction.This research also used regression analysis to observe the effect of the tested scenarios analyzed in VISSIM software compared to the No TSP (-) No BRT base model for all vehicles and for buses only. The developed regression model can predict the effect of each scenario on each studied Measures of Performance (MOE). Minitab statistical software was used to conduct this multiple regression analysis. The developed models with real life data input are able to predict how proposed enhancements change the studied MOEs. The BRT models presented in this research can be used for further sensitivity analysis on a larger regional network in the upcoming regional expansion of the transit system in Central Florida. Since this research demonstrated the operational functionality and effectiveness of BRT and TSP systems in this critical corridor in Central Florida, these systems' accomplishments can be expanded throughout the state of Florida to provide greater benefits to transit passengers. Furthermore, to demonstrate the methodology developed in this research, it is applied to a test corridor along International Drive (I-Drive) in Orlando, Florida. This corridor is key for regional economic prosperity of Central Florida and the novel approach developed in this dissertation can be expanded to other transit systems.
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Date Issued: 2015
Identifier: CFE0005918, ucf:50848
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005918

Title: Data-Driven Simulation Modeling of Construction and Infrastructure Operations Using Process Knowledge Discovery.
Creator: Akhavian, Reza, Behzadan, Amir, Oloufa, Amr, Yun, Hae-Bum, Sukthankar, Gita, Zheng, Qipeng, University of Central Florida
Abstract / Description: Within the architecture, engineering, and construction (AEC) domain, simulation modeling is mainly used to facilitate decision-making by enabling the assessment of different operational plans and resource arrangements, that are otherwise difficult (if not impossible), expensive, or time consuming to be evaluated in real world settings. The accuracy of such models directly affects their reliability to serve as a basis for important decisions such as project completion time estimation and...
Show moreWithin the architecture, engineering, and construction (AEC) domain, simulation modeling is mainly used to facilitate decision-making by enabling the assessment of different operational plans and resource arrangements, that are otherwise difficult (if not impossible), expensive, or time consuming to be evaluated in real world settings. The accuracy of such models directly affects their reliability to serve as a basis for important decisions such as project completion time estimation and resource allocation. Compared to other industries, this is particularly important in construction and infrastructure projects due to the high resource costs and the societal impacts of these projects. Discrete event simulation (DES) is a decision making tool that can benefit the process of design, control, and management of construction operations. Despite recent advancements, most DES models used in construction are created during the early planning and design stage when the lack of factual information from the project prohibits the use of realistic data in simulation modeling. The resulting models, therefore, are often built using rigid (subjective) assumptions and design parameters (e.g. precedence logic, activity durations). In all such cases and in the absence of an inclusive methodology to incorporate real field data as the project evolves, modelers rely on information from previous projects (a.k.a. secondary data), expert judgments, and subjective assumptions to generate simulations to predict future performance. These and similar shortcomings have to a large extent limited the use of traditional DES tools to preliminary studies and long-term planning of construction projects.In the realm of the business process management, process mining as a relatively new research domain seeks to automatically discover a process model by observing activity records and extracting information about processes. The research presented in this Ph.D. Dissertation was in part inspired by the prospect of construction process mining using sensory data collected from field agents. This enabled the extraction of operational knowledge necessary to generate and maintain the fidelity of simulation models. A preliminary study was conducted to demonstrate the feasibility and applicability of data-driven knowledge-based simulation modeling with focus on data collection using wireless sensor network (WSN) and rule-based taxonomy of activities. The resulting knowledge-based simulation models performed very well in properly predicting key performance measures of real construction systems. Next, a pervasive mobile data collection and mining technique was adopted and an activity recognition framework for construction equipment and worker tasks was developed. Data was collected using smartphone accelerometers and gyroscopes from construction entities to generate significant statistical time- and frequency-domain features. The extracted features served as the input of different types of machine learning algorithms that were applied to various construction activities. The trained predictive algorithms were then used to extract activity durations and calculate probability distributions to be fused into corresponding DES models. Results indicated that the generated data-driven knowledge-based simulation models outperform static models created based upon engineering assumptions and estimations with regard to compatibility of performance measure outputs to reality.
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Date Issued: 2015
Identifier: CFE0006023, ucf:51014
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006023

Title: Making Waves, Mixing Colors, and Using Mirrors: The Self-Regulated Learning Support Features and Procedural Rhetoric of Three Whole-Body Educational Games.
Creator: Johnson, Emily, McDaniel, Rudy, Vie, Stephanie, Applen, John, Pigg, Stacey, Lindgren, Robb, University of Central Florida
Abstract / Description: This dissertation investigates the question, (")How can the procedural rhetoric of three whole-body educational games improve the understanding of self-regulated learning with digital technology?(") It explores three whole-body educational games (WBEGs) using a quantitative study, a case study, and analyses of their procedural rhetoric to better understand the roles these types of games can have in teaching digital literacy and self-regulated learning (SRL) skills. The three WBEGs, Waves,...
Show moreThis dissertation investigates the question, (")How can the procedural rhetoric of three whole-body educational games improve the understanding of self-regulated learning with digital technology?(") It explores three whole-body educational games (WBEGs) using a quantitative study, a case study, and analyses of their procedural rhetoric to better understand the roles these types of games can have in teaching digital literacy and self-regulated learning (SRL) skills. The three WBEGs, Waves, Color Mixer, and Light and Mirrors, are each intended to teach science concepts to players. These games are similarly structured in that they all invite players to immerse themselves in the game by standing on the (")screen(") (the games project images on the floor). The WBEGs differ from traditional console video games because they receive input from players via motion-sensing technology, requiring players to make large movements with their bodies to influence elements within the game. This study explains SRL as a complex combination of internal (mental) behavior, external (observable) behavior, and interpersonal (social) behavior, identifying within three WBEGs the presence of elements supporting the SRL behaviors of goal setting, strategy planning, collaboration, progress monitoring, feedback, and reflection. These findings inform the understanding of SRL by revealing that each game includes a different combination of SRL-supporting elements that encourage the use of SRL skills in different ways. SRL scaffolding features are those elements within a WBEG that guide players to use certain SRL strategies, helping and supporting their efforts much like construction scaffolding supports a building as it is being erected. This dissertation also utilizes analyses of procedural rhetoric to investigate the techniques reinforced by the underlying structure of these three WBEGs in an effort to further the understanding of digital literacy in education and sociocultural contexts. All three WBEGs appear to emphasize player agency and collaboration. Waves and Light and Mirrors encourage player strategy, while Color Mixer rewards speed and rote knowledge. These reinforced techniques perpetuate the underlying cultural values of accuracy, collaboration, problem-solving, autonomy, and scaffolding. This study discusses these values in the contexts of education and society.
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Date Issued: 2015
Identifier: CFE0005959, ucf:50799
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005959

Title: Microscopic Safety Evaluation and Prediction for Special Expressway Facilities.
Creator: Wang, Ling, Abdel-Aty, Mohamed, Radwan, Essam, Eluru, Naveen, Lee, JaeYoung, Uddin, Nizam, University of Central Florida
Abstract / Description: Expressways are of great importance and serve as the backbone of a roadway system. One of the reasons why expressways increase travel speeds and provide high level of services is that limited access is provided to permit vehicles to enter or exit expressways. Entering and exiting of vehicles are accomplished through interchanges, which consist of several ramps, thus the spacing between ramps is important. A weaving segment might form when an on-ramp is closely followed by an off-ramp. The...
Show moreExpressways are of great importance and serve as the backbone of a roadway system. One of the reasons why expressways increase travel speeds and provide high level of services is that limited access is provided to permit vehicles to enter or exit expressways. Entering and exiting of vehicles are accomplished through interchanges, which consist of several ramps, thus the spacing between ramps is important. A weaving segment might form when an on-ramp is closely followed by an off-ramp. The geometric design of ramps and the traffic behavior of weaving segments are different from other expressway segments. These differences result in distinct safety mechanisms of these two expressway special facilities. Hence, the safety of these two facilities needs to be addressed.The majority of previous traffic safety studies on expressway special facilities are based on highly aggregated traffic data, e.g., Annual Average Daily Traffic (AADT). This highly aggregated traffic data cannot represent traffic conditions at the time of crashes and also cannot be used in the study of weather and temporal impact on crash occurrence. One way to solve this problem is microscopic safety evaluation and prediction through hourly crash prediction and real-time safety analysis. An hourly crash study averages one or several hours' traffic data in a year and also aggregates crash frequencies in the corresponding hour(s). Then it applies predictive models to determine the statistical relationship between crashes and hourly traffic flow characteristics, such as traffic volume. Real-time safety analysis enables us to predict crash risk and distinguish crashes from non-crashes in the next few minutes using the current traffic, weather, and other conditions.There are four types of crash contributing factors: traffic, geometry, weather, and driver. Among these, traffic parameters have been utilized in all previous microscopic safety studies. On the other hand, the other three factors' impact on microscopic safety has not been widely analyzed. The geometric factors' influence on safety are generally excluded by previous researchers using the matched-case-control method, because the majority of previous microscopic safety studies are on mainlines, where the geometric design of a segment does not change much and geometry does not have a significant effect on safety. Not enough studies have adopted weather factors in microscopic safety analysis because of the limited availability of weather data. The impact of drivers on safety has also not been widely considered since driver information is hard to be obtained. This study explores the relationship between crashes and the four contributing factors. Weather data are obtained from airport weather stations and crash reports which record weather and roadway surface conditions for crashes. Meanwhile, land-use and trip generation parameters serve as surrogates for drivers' behavior.Several methods are used to explore and quantify the impact of these factors. Random forests are used in discovering important and significant explanatory variables, which play significant roles in determining traffic safety, by ranking their importance. Meanwhile, in order to prevent high correlation between independent variables, Pearson correlation tests are carried out before model estimations. Only the variables which are not highly correlated are selected. Then, the selected variables are put in logistic regression models and Poisson-lognormal models to respectively estimate crash risk and crash frequency for special expressway facilities. Meanwhile, in case of correlation among observations in the same segment, a multilevel modeling structure has been implemented. Furthermore, a data mining technique(-)Support Vector Machine (SVM)(-)is used to distinguish crash from non-crash observations. Once the crash mechanisms for special expressway facilities are found, we are able to provide valuable information on how to manage roadway facilities to improve the traffic safety of special facilities. This study adopts Active Traffic Management (ATM) strategies, including Ramp Metering (RM) and Variable Speed Limit (VSL), in order to enhance the safety of a congested weaving segment. RM regulates the entering vehicle volume by adjusts metering rate, and VSL is able to provide smoother mainline traffic by changing the mainline speed limits. The ATM strategies are carried out in microscopic simulation VISSIM through the Component Object Model (COM) interface. The results shows that the crash risk and conflict count of the studies weaving segment have been significantly reduced because of ATM.Furthermore, the mechanisms of traffic conflicts, a surrogate safety measurement, are explored for weaving segments using microscopic simulation. The weaving segment conflict prediction model is compared with its crash prediction model. The results show that there are similarity and differences between conflict and crash mechanisms. Finally, potential relevant applications beyond the scope of this research but worth investigation in the future are also discussed in this dissertation.
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Date Issued: 2016
Identifier: CFE0006414, ucf:51480
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006414

simulation (47)	+ -
Simulation (43)	+ -
modeling (10)	+ -
System Dynamics (8)	+ -
Driving Simulator (7)	+ -

VISSIM (7)	+ -
training (7)	+ -
Modeling (6)	+ -
virtual reality (5)	+ -
Heat Transfer (4)	+ -
Modeling and Simulation (4)	+ -
Numerical Simulation (4)	+ -
Training (4)	+ -
driving simulator (4)	+ -
modeling and simulation (4)	+ -
simulations (4)	+ -
Discrete Event Simulation (3)	+ -
Performance (3)	+ -
Presence (3)	+ -
Simulator (3)	+ -
Traffic Safety (3)	+ -
Traffic Simulation (3)	+ -
Virtual Environment (3)	+ -
discrete event simulation (3)	+ -
interoperability (3)	+ -
learning (3)	+ -
traffic safety (3)	+ -
video games (3)	+ -
workload (3)	+ -
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Honors Collection (11)	+ -

English (278)	+ -
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University of Central Florida (273)	+ -
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Proctor, Michael (20)	+ -
Rabelo, Luis (18)	+ -
Radwan, Essam (16)	+ -

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