Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Ronald Matthews. Vita. Includes bibliographical references. Also available from UMI.

Thesis (Ph. D.)--Purdue University, 2005. / Vita. Includes bibliographical references (p. 167-170). Also available online via the Purdue University website (http://docs.lib.purdue.edu/).

Thesis (M.S.)--Naval Postgraduate School, 2006. / "December 2006." Includes bibliographical references (p. 47-48). Also available online from the Web site of the Naval Postgraduate School (http://www.nps.edu).

Thesis (MScIng)--University of Stellenbosch, 2006. / Bibliography. Also available via the Internet.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains x, 87 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 81-82).

Thesis (Ph. D.)--West Virginia University, 2009. / Title from document title page. Document formatted into pages; contains xv, 194 p. : ill. (some col.), col. maps. Includes abstract. Includes bibliographical references (p. 180-188).

Thesis (PhD) - Swinburne University of Technology, School of Engineering and Science, 2009. / A thesis submitted in accordance with the regulations for the degree of Doctor of Philosophy, School of Engineering and Science, Swinburne University of Technology, 2009. Typescript. Includes bibliographical references (p. 315-330)

Both mental workload and inhibitory control have previously been found to relate to road traffic collisions and these factors are also believed to be highly dependent on the prefrontal cortex. Driving simulators create a safe environment in which to manipulate these factors and examine human behaviours. However, the validity of simulators is often called in to question and previous simulator validation research has a number of common methodological issues. As such, there were two main aims of this thesis. The first was to examine the efficacy of functional near infrared spectroscopy in measuring changes in prefrontal cortex activation as a result of mental workload and inhibitory control manipulations in simulated driving scenarios. The second aim was to examine the similarities and differences in driving behaviour, eye movements and prefrontal cortex activation in real and simulated driving environments. In Experiment One mental workload was examined using a simulated driving task which used different road types to manipulate workload in a medium fidelity driving simulator. Results showed changes in subjective workload ratings with changes in road types, with dual carriageway roads having the lowest mental workload followed by A-roads, city centre routes and suburb roads, which had the highest workload demands. Increases in mental workload were accompanied by reductions in speed and mean fixation duration and increases in accelerations, horizontal spread of search, skin conductance responses and the concentration of oxygenated haemoglobin in the prefrontal cortex. In Experiments Two and Three, inhibitory control was examined in both a high and medium fidelity simulator. Inhibition was manipulated by using different hazard types and by changing the role of the participant to active or passive. Results showed changes in prefrontal cortex activation with changes in hazard type in the high fidelity simulator. Although the same pattern of results was found in the medium fidelity simulator the magnitude of change was lower and results were not statistically significant. Subjective ratings of risk and mental workload also showed an increased magnitude of change from everyday to hazardous driving in the high fidelity simulator suggesting that it may be a more useful tool for comparing hazardous scenarios than the medium fidelity simulator. Results also revealed greater activation for active than passive participants for oxygenated haemoglobin. In Experiment Four, driving behaviour and eye movements were compared between real world and simulated driving at both high and medium fidelities using the same road definitions as in Experiment One. Results showed that participants had reduced speeds and spread of search and increased accelerations and mean fixation durations in the car. However, changes in driving behaviours and eye movements in all environments were consistent with the patterns seen in Experiment One. More specifically, there were increases in acceleration and spread of search and reductions in speed and fixation duration with increased mental workload. These results demonstrate relative validity for both simulators. Behavioural equivalence was found between the high and medium fidelity simulator for all eye movement and speed measures and two (right and absolute) of the five acceleration signatures. Finally, Experiment Five compared the similarities and differences in driver behaviour and prefrontal cortex activation as measured using functional near infrared spectroscopy in on-road and high fidelity simulated driving. Results showed reduced speed and increased acceleration in the car compared to the simulator but as with Experiments One and Four there were increases in acceleration and reductions in speed with increased workload in both environments, showing support for relative validity for driver behaviour measures. Prefrontal cortex activation did not show meaningful patterns of activation in either environments or across changes in road types. It was concluded that functional near infrared spectroscopy is a valuable neuroimaging technique that can be used to detect mental workload changes and prefrontal cortex responses to hazardous situations in controlled, simulated environments. However, it is currently not an effective technique for determining these changes in mental workload in real world driving where experimental control is reduced. With respect to simulator validation, driver behaviour and eye movements differ numerically between on-road and simulated driving but show the same direction of change with changes in road demands. As such, there is relative validity for both medium and high fidelity simulated driving and behavioural equivalence between the two levels of simulator fidelity.

This thesis contributes to the reliability and aging studies of supercapacitors for more efficient use in EV/HEV applications. This thesis demonstrates the effect of aging/failure in supercapacitor cells and module cells using accelerated tests employed to expedite the aging process. The tests, as explained below were categorized based on operational and environmental aging factors associated with supercapacitor failure in EV/HEV applications to; • Investigate supercapacitor cell performance at high temperature and constant voltage individual conditions, and also simultaneously (known as calendar test) • Investigate the effect of voltage balancing/equalization circuits on supercapacitor module cells’ performance during constant current cycling tests under certain environmental and electrical factors • Investigate supercapacitor module cells’ cycling performance in a lab-scale designed electrical DC programmable motor load system that emulates supercapacitor operational conditions in an EV/HEV application. The aging behaviors characterized by the three factors mentioned above are quantified in this thesis through the periodic monitoring of their electrical and electrochemical state of health with Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, and Constant Current characterization tests. These tests help identity aging modes in supercapacitors, and it was observed that regardless of their aging factors; an increase in ESR and decrease of capacitance was determined. Although this information is required, the results from Electrochemical Impedance Spectroscopy (EIS) tests revealed more details distinctive to each aging factor. From this distinction, the aging mechanisms in relation to the aging factors, which causes the deterioration in the supercapacitor electrical performance, are identified and summarized as the following: 1. Loss of contact within supercapacitor electrode, given rise to the contact resistance due to the presence of high temperature as the main aging factor 2. Change of supercapacitor porous electrode emulating a charge transfer reaction thereby increasing its distributed resistance, caused by the effect of high voltage or cycling Mathematical models in the form of electrical equivalent circuits (EECs) distinctive of their aging factors are generated from EIS electrochemical behaviors to easily describe aging behaviors in supercapacitors. The EEC models developed using impedance modeling generated an initial model from dormant cells, which transitioned to aging models distinctive of their aging factors as soon as a 100% increase in ESR and/or an 80% decrease in capacitance is observed. The proposed EEC models were validated to show the dynamic interaction between aging of the supercapacitor cells on their electrical performance in both frequency and time domains. In summary, the EEC models encompass this thesis objective and as such considered the main contribution of this research work.

Malaysia has a worrying road fatality rate compared to many other countries, and the high number of registered motorcycles (vulnerable road users) in the country is one of its most distinctive characteristics. However there has previously been limited experimental research on driving conducted in Malaysia. This thesis aimed to investigate Malaysian drivers’ ability to perceive other road users (cars and motorcycles) and how they make judgments about the safety of pulling out at junctions. Malaysian drivers’ performance in these tasks was compared with UK drivers (Chapter Two). Various studies were also conducted to investigate how different factors affect drivers’ perception and judgment, such as time of day and use of headlights (Chapter Three), a honking sound (Chapter Four), motion and speed (Chapter Five). Chapter Six went on to investigate drivers’ ability to judge the intention of other road users. This series of experiments has provided new insights about the perception and judgment of Malaysian drivers. Possibly due to the higher exposure to motorcycles, Malaysians have a better ability to detect approaching motorcycles than UK drivers though they are also more likely to judge that it was safe to pull out at junctions. In addition, the number of incorrect judgments made by Malaysian drivers about the safety of pulling out is a concern especially where a collision would happen based on the decision. Moreover, switching on headlights increased drivers’ ability to perceive other vehicles during night time but not necessarily during day time. However, switching on headlights decreased the likelihood of drivers judging that it was safe to pull out in front of motorcycles regardless of time of day. The results also suggested that a honking sound did not facilitate the ability to perceive other vehicles, but did decrease drivers’ tendency to judge that it was safe to pull out. Lastly, it was shown that it is important to provide reliable signals in order to improve road safety. In dynamic video stimuli, signalling is more informative for judging the intention of approaching cars than motorcycles, which could lead to poor judgment making about approaching motorcycles at junctions.