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Visual discomfort is the adverse sensations, such as headaches and eyestrain, encountered on viewing certain stimuli. These sensations can arise under certain viewing conditions, such as stereoscopic viewing and prolonged reading of text patterns. Also, discomfort can occur as a result of viewing stimuli with certain spatial properties, including stripes and filtered noise patterns of particular spatial frequency. This thesis is an exploration of the stimulus properties causing discomfort, within the framework of two theoretical explanations. Both of the explanations relate to the stimuli being difficult for the visual system to process. The first is concerned with discomfort being the result of inefficient neural processing. Neural activity requires energy to process information, and stimuli that demand a lot of energy to be processed might be uncomfortable. The second explanation revolves around uncomfortable stimuli not being effective in driving the accommodative (focussing) response. Accommodation relies on the stimulus as a cue to drive the response effectively - an uninformative cue might result in discomfort from an uncertain accommodative response. The following research investigates both these possibilities using a combination of psychophysical experimentation, questionnaire-based surveys on non-clinical populations, and computational modelling. The implications of the work for clinical populations are also discussed.

This study was conducted to measure the reliability of fatigue measures in an intermittent overhead work task. Fatigue measures included several EMG based parameters and subjective discomfort ratings through use of the Borg CR-10 scale. This study was part of a larger existing study that simulates overhead work in an automobile manufacturing plant. Ten participants used a drill tool to perform an overhead tapping task for one hour at a height relative to individual anthropometry. Reliability indexes, including Intraclass Correlation Coefficients, Standard Errors of Measurement, and Coefficients of Variation were determined for each fatigue measure for each of three shoulder muscles (anterior deltoid, middle deltoid, and trapezius). High reliability implies repeatable results, and precise and credible methods. Conversely, measurement error and subject variability can lead to low reliability of measures. The results indicated that ratings of perceived discomfort (RPD) parameters (slope and final rating) showed relatively high reliability. Intercepts for mean power frequency (MnPF), median power frequency (MdPF), and root means square (RMS) also showed very high reliability. Actual slopes for MnPF, MdPF, and RMS showed low reliability overall, and normalizing slopes did not necessarily improve reliability. Taking the absolute value of slopes led to a noticeable increase in reliability. RPD slope did not correlate with any of the EMG slopes. The high reliability of RPD parameters allows for its inexpensive application to the industrial setting for similar overhead tasks. The reliability of EMG intercepts implies consistent methods; however the reliability of overall EMG trends is suspect if the slope is not reliable. Some EMG slope parameters show promise; however, more research is needed to determine if these parameters are reliable for complex tasks. / Master of Science

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / Revisión por pares

The following study aims to understand the effects Acceptance and Commitment Therapy, or ACT, has on individuals who have experienced discomfort through exposure to aversive stimuli. Experiencing discomfort is a natural part of human life. Each person has their own class of responses to respond to discomfort. A typical response may include avoiding an object, person, or situation that had made the person uncomfortable in the past. Batten, Follette, and Aban (2001) found that women who experienced childhood sexual abuse and scored high in experiential avoidance where more likely to engage in high risk sexual behaviors. Avoiding discomfort can have serious repercussions. ACT has been a proven therapy to treat anxiety, gambling, PTSD, eating disorders among other disorders. Previous studies show the effectiveness of ACT on treating discomfort (Cohrane, Barnes-Holmes, & Barnes-Holmes, 2008; Hayes, Bissett, Korn, Zettle, Rosenfarb, Cooper, & Grundt, 1999; Luciano, et al., 2010). This study extends the findings and further supports the utility of ACT to treat discomfort through a laboratory study. This study exposes participants to “disgusting” stimuli to evoke disgust and discomfort. A brief ACT session is administered to half the participants which is compared to a control task which includes a distraction/avoidance task. Findings from this study suggest the utility of ACT to increase tolerance to discomfort.

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This research effort focused on ascertaining the headlamp technology (of the eleven specified) that minimized the amount of discomfort glare and maximized the visibility of three types of pavement marking materials used in the study. Two baseline conditions, halogen low beam (HLB) and high-intensity discharge (HID) were measured both individually and in combination with three levels of UV-A. In addition, three other headlamp configurations were evaluated. Discomfort glare was measured subjectively for each headlamp configuration. Pavement marking visibility was directly measured via pavement marking detection distances. Thirty participants representing three age groups participated in this study: young (18-25 years old), middle (40-50 years old), and older (60 years and older). The headlamp technology and the pavement marking material needed to be beneficial for all age groups as all would potentially use the new technology if it were implemented in vehicles and roadways in the future. Participants evaluated discomfort glare at both a far and close distance using the nine-point DeBoer scale and evaluated pavement marking visibility by indicating when they could see the first and last pavement markings in each of the three sections. Overall, it was found that the HID configurations (HID, Middle UV-A + HID, High UV-A + HID) with a sharp cut-off beam pattern provided the least amount of discomfort glare. In contrast, the halogen configurations (HLB, Hybrid UV-A + HLB, Middle UV-A + HLB, High UV-A + HLB) and high output halogen with a straight-ahead beam pattern provided the longest detection distances. Two of the pavement markings: a two part liquid system (developed by 3M) and a fluorescent paint provided longer detection distances than a thermoplastic marking. / Master of Science

In recent years increased emphasis has been placed on improving seat comfort in automobiles. This is partly due to research showing that prolonged driving is associated with increased risk of musculoskeletal disorders, but largely because driver comfort is now viewed as an increasingly important aspect of the competitive marketing of vehicles. Driving is firmly cemented as a major part of most people s daily life across the world and people are now spending more time in their vehicles than ever before. As urban congestion continues to rise, commuting distances and durations will progressively increase, subjecting drivers to the risks of long duration driving more often. Consequently the automotive industry has invested in designing seats that perform better under increased usage durations and ergonomics has played a vital role in the design of new seats. However, the ability to design a successful seat relies heavily on the capacity to accurately evaluate the comfort of a vehicle seat and one major issue that has been highlighted with the current state of automotive ergonomics research is the standardisation of comfort evaluation techniques. This research aimed to tackle these issues by investigating the effects of long duration driving on discomfort and the range factors associated with driver discomfort. Furthermore, the ultimate goal of this research was develop and evaluate a novel objective measure of driver discomfort that focused on driver seat fidgets and movements (SFMs) with the aim of standardising discomfort evaluation within the automotive industry. Three laboratory studies and one field observation were conducted to address these aims whereby subjective and objective evaluations of discomfort were conducted during long term driving (ranging from 60 - 140 minutes). The results determined that a measure of driver SFMs can be effectively implemented into long duration driving trials to evaluate the effects of long term driving and vibration exposure on driver discomfort and subsequently used to make accurate predictions of overall discomfort. Large positive correlations have been determined between measures of SFMs and subjective ratings of overall discomfort (r2 > 0.9, P < 0.05) and the SFM method has been successfully repeated under a range of driving conditions. Driver seat fidget and movement (SFM) frequency is shown to significantly increase congruently with subjective ratings over the duration of a long term drive as drivers seek to cope with increased discomfort. It is proposed that drivers will record movements in the vehicle seat when discomfort reaches a threshold that is consciously or unconsciously perceived and as the duration of driving accrues, drivers will reach this threshold with increased frequency. A measure of both SFM frequency and total accumulative SFMs have been shown to accurately predict discomfort ratings and provides the basis for discomfort evaluations to be made via remote monitoring, removing the need for subjective assessment. During a long term drive, there becomes a point upon which improvements in seat design become ineffective as extended duration driving will result in discomfort regardless of how well the seat has been designed. It was shown that drivers will move in the vehicle seat to cope with increased discomfort and in addition, another method of combatting the negative effects of long term driving was investigated. Subjective and objective evaluation determined that breaks from driving will reduce discomfort both immediately and upon completion of a long term drive. Furthermore, these benefits were increased when drivers left the vehicle seat as discomfort was reset when drivers took a 10 minute walk. Walking during a break from driving can be considered the ultimate SFM. Drivers are recommended to plan breaks from driving when conducting a long duration journey in order to minimise discomfort and when taking a break, drivers should take a walk rather than remain seated in the vehicle.

The role of internal audit has changed during the past few years. Today, internal auditors are central players in organizations’ corporate governance structure. However, previous studies show that there is a gap between internal auditors’ own perception of their role compared to their stakeholders’. The wide scope of internal auditors’ role risks placing internal auditors in a situation of conflict, where consulting services threaten their provision of assurance services. In order to provide clarification to the role, this thesis studies how internal auditors become comfortable in their role, as both assurance and consulting providers and what concerns internal auditors face in their work. In order to fulfill the aim following research question is asked: How do internal auditors become comfortable in their role within risk management? Ten internal auditors were interviewed in order to make a contribution in the field of internal audit. The findings suggest that both assurance and consulting services are needed in order for internal auditors to feel they add value to the organization and hence, become comfortable in their role. Internal auditors’ comfort is many times dependent on fulfilling their stakeholders’ needs, however, staying in the scope of their role was shown to be more important.