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A study of nonlinear dynamics of EEG responses to simulated unmanned vehicle tasks
Title
A study of nonlinear dynamics of EEG responses to simulated unmanned vehicle tasks.
Creator
Xu, Ziqing, Karwowski, Waldemar, Hancock, Peter, Reinerman, Lauren, Mikusinski, Piotr, University of Central Florida
Abstract / Description
In the contemporary world, mental workload becomes higher as technology evolves and task demand becomes overwhelming. The operators of a system are usually required to complete tasks with higher complicity within a shorter period of time. Continuous operation under a high level of mental workload can be a major source of risk and human error, thus put the operator in a hazardous working environment. Therefore, it is necessary to monitor and assess mental workload. In this study, an unmanned...
Show moreIn the contemporary world, mental workload becomes higher as technology evolves and task demand becomes overwhelming. The operators of a system are usually required to complete tasks with higher complicity within a shorter period of time. Continuous operation under a high level of mental workload can be a major source of risk and human error, thus put the operator in a hazardous working environment. Therefore, it is necessary to monitor and assess mental workload. In this study, an unmanned vehicle operation with visual detection tasks was investigated by means of nonlinear analysis of EEG time series. Nonlinear analysis is considered more advantageous compared with traditional power spectrum analysis of EEG. Besides, nonlinear analysis is more capable to capture the nature of EEG data and human performance, which is a process that subjects to constant changes. By examining the nonlinear dynamics of EEG, it is more likely to obtain a deeper understanding of brain activity.The objective of this study is to investigate the mental workload under different task levels through the examination of brain activity via nonlinear dynamics of EEG time series in simulated unmanned ground vehicle visual detection tasks.The experiment was conducted by the team lead by Dr. Lauren Reinerman Jones at Institute for Simulation (&) Training, University of Central Florida. One hundred and fifty subjects participated the experiment to complete four visual detection task scenarios (1) change detection, (2) threat detection task, (3) dual task with different change detection task rates, and (4) dual task with different threat detection task rates. Their EEG was recorded during performing the tasks at nine EEG channels. This study develops a massive data processing program to calculate the largest Lyapunov exponent, correlation dimension of the EEG data. This study also develops the program for performing 0-1 test on the EEG data in Python language environment. The result of this study verifies the existence of chaotic dynamics in EEG time series, reveals the change in brain activity as the effect of changing task demand in more detailed level, and obtains new insights from the psychophysiological mental workload measurement used in the preliminary study. The results of this study verified the existence of the chaotic dynamics in the EEG time series. This study also supported the hypothesis that EEG data exhibits change in the level of nonlinearity corresponding to differed task levels. The nonlinear analysis of EEG time series data is able to discriminate the change in brain activity derived from the changes in task load. All nonlinear dynamics analysis techniques used in this study is able to find the difference of nonlinearity in EEG among task levels, as well as between single task scenario and dual task scenario.
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Date Issued
2019
Identifier
CFE0007558, ucf:52615
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0007558
USING MODELING AND SIMULATION TO EVALUATE DISEASE CONTROL MEASURES
Title
USING MODELING AND SIMULATION TO EVALUATE DISEASE CONTROL MEASURES.
Creator
Atkins, Tracy, Clarke, Thomas, University of Central Florida
Abstract / Description
This dissertation introduced several issues concerning the analysis of diseases by showing how modeling and simulation could be used to assist in creating health policy by estimating the effects of such policies. The first question posed was how would education, vaccination and a combination of these two programs effect the possible outbreak of meningitis on a college campus. After creating a model representative of the transmission dynamics of meningitis and establishing parameter values...
Show moreThis dissertation introduced several issues concerning the analysis of diseases by showing how modeling and simulation could be used to assist in creating health policy by estimating the effects of such policies. The first question posed was how would education, vaccination and a combination of these two programs effect the possible outbreak of meningitis on a college campus. After creating a model representative of the transmission dynamics of meningitis and establishing parameter values characteristic of the University of Central Florida main campus, the results of a deterministic model were presented in several forms. The result of this model was the combination of education and vaccination would eliminate the possibility of an epidemic on our campus. Next, we used simulation to evaluate how quarantine and treatment would affect an outbreak of influenza on the same population. A mathematical model was created specific to influenza on the UCF campus. Numerical results from this model were then presented in tabular and graphical form. The results comparing the simulations for quarantine and treatment show the best course of action would be to enact a quarantine policy on the campus thus reducing the maximum number of infected while increasing the time to reach this peak. Finally, we addressed the issue of performing the analysis stochastically versus deterministically. Additional models were created with the progression of the disease occurring by chance. Statistical analysis was done on the mean of 100 stochastic simulation runs comparing that value to the one deterministic outcome. The results for this analysis were inconclusive, as the results for meningitis were comparable while those for influenza appeared to be different.
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Date Issued
2010
Identifier
CFE0003232, ucf:48535
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003232
A Production and Cost Modeling Methodology of 2nd Generation Biofuel in the United States
Title
A Production and Cost Modeling Methodology of 2nd Generation Biofuel in the United States.
Creator
Poole, David, Kincaid, John, Mollaghasemi, Mansooreh, Geiger, Christopher, University of Central Florida
Abstract / Description
The use of biofuels in the United States has increased dramatically in the last few years. The largest source of feedstock for ethanol to date has been corn. However, corn is also a vitally important food crop and is used commonly as feed for cattle and other livestock. To prevent further diversion of an important food crop to production of ethanol, there is great interest in developing commercial-scale technologies to make ethanol from non-food crops, or other suitable plant material. This...
Show moreThe use of biofuels in the United States has increased dramatically in the last few years. The largest source of feedstock for ethanol to date has been corn. However, corn is also a vitally important food crop and is used commonly as feed for cattle and other livestock. To prevent further diversion of an important food crop to production of ethanol, there is great interest in developing commercial-scale technologies to make ethanol from non-food crops, or other suitable plant material. This is commonly referred to as biomass. A review is made of lignocellulosic sources being considered as feedstocks to produce ethanol. Current technologies for pretreatment and hydrolysis of the biomass material are examined and discussed. Production data and cost estimates are culled from the literature, and used to assist in development of mathematical models for evaluation of production ramp-up profiles, and cost estimation. These mathematical models are useful as a planning tool, and provide a methodology to estimate monthly production output and costs for labor, capital, operations and maintenance, feedstock, raw materials, and total cost. Existing credits for ethanol production are also considered and modeled. The production output in liters is modeled as a negative exponential growth curve, with a rate coefficient providing the ability to evaluate slower, or faster, growth in production output and its corresponding effect on monthly cost. The capital and labor costs per unit of product are determined by dividing the monthly debt service and labor costs by that month?s production value. The remaining cost components change at a constant rate in the simulation case studies. This methodology is used to calculate production levels and costs as a function of time for a 25 million gallon per year capacity cellulosic ethanol plant. The parameters of interest are calculated in MATLAB with a deterministic, continuous system simulation model. Simulation results for high, medium, and low cost case studies are included. Assumptions for the model and for each case study are included and some comparisons are made to cost estimates in the literature. While the cost per unit of product decreases and production output increases over time, some reasonable cost values are obtained by the end of the second year for both the low and medium cost case studies. By the end of Year 2, total costs for those case studies are $0.48 per liter and $0.88 per liter, respectively. These cost estimates are well within the reported range of values from the reviewed literature sources. Differing assumptions for calculations made by different sources make a direct cost comparison with the outputs of this modeling methodology extremely difficult. Proposals for reducing costs are introduced. Limitations and shortcomings of the research activity are discussed, along with recommendations for potential future work in improving the simulation model and model verification activities. In summary, the author was not able to find evidence?within the public domain?of any similar modeling and simulation methodology that uses a deterministic, continuous simulation model to evaluate production and costs as a function of time. This methodology is also unique in highlighting the important effect of production ramp-up on monthly costs for capital (debt service) and labor. The resultant simulation model can be used for planning purposes and provides an independent, unbiased estimate of cost as a function of time.
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Date Issued
2012
Identifier
CFE0004424, ucf:49321
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004424
THE INCOMPATIBILITY OF FREEDOM OF THE WILL AND ANTHROPOLOGICAL PHYSICALISM
Title
THE INCOMPATIBILITY OF FREEDOM OF THE WILL AND ANTHROPOLOGICAL PHYSICALISM.
Creator
Gonzalez, Ariel, Rodgers, Travis, University of Central Florida
Abstract / Description
Many contemporary naturalistic philosophers have taken it for granted that a robust theory of free will, one which would afford us with an agency substantial enough to render us morally responsible for our actions, is itself not conceptually compatible with the philosophical theory of naturalism. I attempt to account for why it is that free will (in its most substantial form) cannot be plausibly located within a naturalistic understanding of the world. I consider the issues surrounding an...
Show moreMany contemporary naturalistic philosophers have taken it for granted that a robust theory of free will, one which would afford us with an agency substantial enough to render us morally responsible for our actions, is itself not conceptually compatible with the philosophical theory of naturalism. I attempt to account for why it is that free will (in its most substantial form) cannot be plausibly located within a naturalistic understanding of the world. I consider the issues surrounding an acceptance of a robust theory of free will within a naturalistic framework. Timothy O'Connor's reconciliatory effort in maintaining both a scientifically naturalist understanding of the human person and a full-blooded theory of agent-causal libertarian free will is considered. I conclude that Timothy O'Connor's reconciliatory model cannot be maintained and I reference several conceptual difficulties surrounding the reconciliation of agent-causal libertarian properties with physical properties that haunt the naturalistic libertarian.
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Date Issued
2014
Identifier
CFH0004628, ucf:45292
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFH0004628