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Real-Time FNIRS Investigation of Discrete and Continuous Cognitive Demands During Dual-Task WalkingRahman, Tabassum Tahmina 13 September 2019 (has links)
Younger adults who are walking and doing additional tasks at the same time may not
realize if their performance suffers, putting some at greater risk for injury and impairment during
certain tasks. This thesis has addressed this confound by developing a divided attention paradigm
focusing on discrete and continuous demand manipulations. The work assessed in motorcognitive processing changes with cerebral and behavioral monitoring of over-ground walking
with or without cognitive tasks. Participants (n = 19, 18-35 years, 13 females) were asked to
walk at their usual pace [usual walking condition (SM)], walk at their usual pace while
performing a cognitive task [dual-task condition (DT)] as well as conduct a cognitive task while
standing [single cognitive condition (SC)]. All participants conducted two discrete [simple
response time (SRT) & go-no-go (GNG)] and two continuous cognitive tasks [N-back (NBK) &
double number sequence (DNS)] of increasing demand.
The study revealed significant brain and behavior interactions during the most demanding
continuous cognitive task, the DNS. The findings demonstrated lower accuracy rates, slower
walk speeds as well as greater cerebral oxygenation in DNS DT in comparison to single task
conditions. With increasing cognitive demands and tasks, there were longer response times, as
well as lower accuracy rates. The behavioral findings were qualified by marginally significant
interactions in a 2 x 4 RM ANOVA between SC-DT task and demand for accuracy rate [F (3,
54) = 2.66, p = 0.06, η2 =.13], significant interactions in response time [F (2, 36) = 4.1, p =
0.026, η2 =.18] as well as significant SM-DT task and demand findings for walk speed [F (3, 54)
=5.3, p = 0.003, η2 =.23]. The 2 x 2 x 4 RM ANOVA revealed significant HbO2 interactions
between walking tasks (single and dual), hemisphere and demand [F (3, 54) = 5.730, p = 0.002,
η2 =.24] in the DNS only.
The data suggests that greater demand manipulations with continuous cognitive tasks
may be sensitive to both prefrontal cortex (PFC) and behavioral assessments in younger adults
(YA). Further validation of the discrete-continuous demand paradigm in motor studies may
provide a basis for cognitive assessment with applications in motor learning, cognitive training,
aging and more.
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Movement sensor using image correlation on a multicore platformLind, Christoffer, Green, Jonas, Ingvarsson, Thomas January 2012 (has links)
The purpose of this study was to investigate the possibility to measure speed of a vehicle usingimage correlation. It was identified that a new solution of measuring the speed of a vehicle, astoday’s solution does not give the True Speed Over Ground, would open up possibilities of highprecision driving applications. It was also the intention to evaluate the performance of theproposed algorithm on a multicore platform. The study was commissioned by HalmstadUniversity.The investigation of image correlation as a method to measure speed of a vehicle was conductedby applying the proposed algorithm on a sequence of images. The result was compared toreference points in the image sequence to confirm the accuracy. The performance of the multicoreplatform was measured by counting the clock cycles it took to perform one measurement cycle ofthe algorithm.It was found out that using image correlation to measure speed has a positional accuracy of closeto a half percent. The results also revealed that one measurement cycle of the algorithm could beperformed in close to half a millisecond and the achieved parallel utilization of the multicoreplatform was close to eighty-seven percent.It was concluded that the algorithm performed well within the limit of acceptance. A conclusionabout the performance was that low execution time of a measurement cycle makes it possible toexecute the algorithm at a frequency of eighteen hundred Hertz. With a frequency that high, incombination with the camera settings proposed in the thesis, the algorithm would be able tomeasure speeds close to one thousand one hundred kilometers per hour.The authors recommend that future work should be focused on investigating the cameraparameters to be able to optimize both the memory and computational requirements of theapplication. It is also recommended to look closer at the algorithm and the possibilities ofdetecting transversal and angular changes as it would open up for other application areas,requiring more than just the speed.
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