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- Dahlman, Joakim, 1974-
(författare)
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Psychophysiological and Performance Aspects on Motion Sickness
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Motion sickness is not an illness, but rather a natural autonomic response to an unfamiliar or specific stimulus. The bodily responses to motion sickness are highly individual and contextually dependent, making them difficult to predict. The initial autonomic responses are similar to the ones demonstrated when under stress. When under the influence of motion sickness, motivation and ability to perform tasks or duties are limited. However, little is known about how specific cognitive functions are affected. Furthermore, standard mitigation strategies involve medications that induce fatigue or strategies that require cognitive capabilities. Both of them may result in reduced capability to perform assigned tasks or duties. Hence, there is a need for alternative mitigation strategies.The aim of the thesis was to study psychophysiological and performance aspects on motion sickness. The long-term goal is to provide strategies for mitigation and prevention of motion sickness by identifying psychophysiological responses as predictors for both wellbeing and performance. This thesis comprises four studies, in which 91 participants were exposed to two different motion sickness stimuli, either an optokinetic drum or a motion platform. Before the tests, a method for extracting fixations from eye-tracking data was developed as a prerequisite for studying fixations as a possible mitigation strategy for reducing motion sickness. During exposure to stimuli that triggers motion sickness, performance was studied by testing short-term memory and encoding and retrieval. In the final study, the effects of an artificial sound horizon were studied with respect to its potential to subconsciously function as a mitigating source.The results of the measurements of the psychophysiological responses were in accordance with previous research, confirming the ambiguity and high individuality of the responses as well as their contextual dependencies. To study fixations, a centroid mode algorithm proved to be the best way to generate fixations from eye-movement data. In the final study, the effects of the sound horizon were compared to the effects of a non-positioned sound. In the latter condition, both fixation time and the number of fixations increased over time, whereas none of them showed a significant time effect in the sound horizon condition. The fixation time slope was significantly larger in the non-positioned sound condition compared to the sound horizon condition. Number of fixations, heart rate, and skin conductance correlated positively with subjective statements that referred to motion sickness. Among participants that were susceptible to motion sickness symptoms, short-term memory performance was negatively affected. However, no effects of motion sickness on encoding and retrieval were found, regardless of susceptibility.Future studies should continue focusing on autonomic responses and psychological issues of motion sickness. Factors such as motivation, expectancies, and previous experiences play a major and yet relatively unknown role within the motion sickness phenomena.
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- Earl, Robyn, et al.
(författare)
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Visual search strategies of pedestrians with and without visual and cognitive impairments in a shared zone : A proof of concept study
- 2016
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Ingår i: Land use policy. - : Elsevier. - 0264-8377 .- 1873-5754. ; 57, s. 327-334
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Tidskriftsartikel (refereegranskat)abstract
- Shared zones have gained increasing popularity in urban land use and design as a means of incorporating the needs of multiple modes of transport, while at the same time promoting social interaction between users. Interactions within shared zones are based on a set of informal social protocols, communicated via eye contact and social cues. This proof of concept study utilised eye-tracking technology to examine the visual search strategies of individuals, with and without visual and cognitive impairments as they navigated a strategically chosen shared zone. In total 3960 fixations were analysed and the fixations were distributed across the shared zone and a pedestrian crossing. Those with impairments were more likely to fixate on traffic specific areas and objects compared to those without, suggesting that they required more input ascertaining when and where it was safe to perform tasks. However, the duration of fixation was not significantly different for an object whether it was traffic related or not, indicating a global need for increased processing time of the surrounding environment. Shared zones are claimed to increase driver awareness and safety and reduce congestion, but the implications on participation and safety for those with visual and cognitive impairments is yet to be extensively explored.
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- Dukic, Tania, 1975, et al.
(författare)
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Effects of drivers' age and push button locations on visual time off road, steering wheel deviation and safety perception
- 2006
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Ingår i: Ergonomics. - : Informa UK Limited. - 0014-0139 .- 1366-5847. ; 49:1, s. 78-92
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Tidskriftsartikel (refereegranskat)abstract
- The study examined the effects of manual control locations on two groups of randomly selected young and old drivers in relation to visual time off road, steering wheel deviation and safety perception. Measures of visual time off road, steering wheel deviations and safety perception were performed with young and old drivers during real traffic. The results showed an effect of both driver's age and button location on the dependent variables. Older drivers spent longer visual time off road when pushing the buttons and had larger steering wheel deviations. Moreover, the greater the eccentricity between the normal line of sight and the button locations, the longer the visual time off road and the larger the steering wheel deviations. No interaction effect between button location and age was found with regard to visual time off road. Button location had an effect on perceived safety: the further away from the normal line of sight the lower the rating.
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- Falkmer, Torbjörn, et al.
(författare)
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Usability of the SAFEWAY2SCHOOL system in children with cognitive disabilities
- 2014
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Ingår i: European Transport Research Review. - : Springer Berlin/Heidelberg. - 1867-0717 .- 1866-8887. ; 6:2, s. 127-137
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Tidskriftsartikel (refereegranskat)abstract
- SAFEWAY2SCHOOL is a programme based on several systems for the enhancement of school transportation safety for children. The aim of the study was to explore whether children with cognitive disabilities will notice, realise, understand, trust and accept the SAFEWAY2SCHOOL system and act in accordance with its instructions. Methods: Fourteen children with cognitive disabilities and a control group of 23 children were shown five videos of scenarios involving journeys to and from school. During the first viewing visual scanning patterns were recorded with an eye tracking device. After a second viewing the participant was asked ten questions per scenario. Five questions addressed what the children saw on the video, and the remaining five what they would need to know and/or do within the scenario. Additional ratings of trust, likability, acceptability and usability were also collected. Results: Very few differences were found in the visual scanning patterns of children with disabilities compared to children who participated in the control group. Of the 50 questions regarding what children saw or needed to know and/or do, only one significant difference between groups was found. No significant differences were found regarding self-reported ratings of trust, acceptability or usability of the system. Despite some significant differences across five of the 11 likability aspects, ratings were consistently high for both groups. Conclusions: Children with cognitive disabilities proved that the SAFEWAY2SCHOOL system is as useful for them as it was for children in the control group. However, a valid estimation of the full utility of SAFEWAY2SCHOOL requires in situ testing of the system with these children. © 2013 The Author(s).
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- Söderberg, Håkan, 1966, et al.
(författare)
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In video war games, are military personnel's fixation patterns different compared with those of civilians?
- 2012
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Ingår i: The Journal of Defense Modeling and Simulation: Applications, Methodology, Technology. - : Sage Publications. - 1557-380X .- 1548-5129. ; 11:4, s. 329-338
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Tidskriftsartikel (refereegranskat)abstract
- For combat personnel in urban operations, situational awareness is critical and of major importance for a safe and efficient performance. One way to train situational awareness is to adopt video games. Twenty military and 20 civilian subjects played the game “Close Combat: First to Fight” on two different platforms, Xbox and PC, wearing an eye tracker. The purpose was to investigate if the visual search strategies used in a game correspond to live training, and how military-trained personnel search for visual information in a game environment. A total of 27,081 fixations were generated through a centroid mode algorithm and analyzed frame-by-frame, 48% of them from military personnel. Military personnel’s visual search strategies were different from those of civilians. Fixation durations were, however, equally short, that is, about 170 ms, for both groups. Surprisingly, the military-trained personnel’s fixation patterns were less orientated towards tactical objects and areas of interest than the civilians’; the underlying mechanisms remaining unclear. Military training was apparently not advantageous with respect to playing “Close Combat: First to Fight”. Further research within the area of gaming, military training and visual search strategies is warranted.
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