The assessment of physical activity is of great interest to the public and to researchers. One of the most popular and objective methods of assessing physical activity is using motion sensors such as pedometers and accelerometers. The purpose of this study was to assess the accuracy and reliability of step counting and energy expenditure estimation of two popular electronic pedometers and one accelerometer during running. In all step-counting trials, actual step counts were determined using a hand tally counter. Twenty subjects (18-40 years) were asked to volunteer to participate in the study. During the initial assessment subjects ran at five, six, seven, and eight miles per hour on a motor driven treadmill for ten minutes at each speed. While running they wore two pedometers and an accelerometer while oxygen consumption was measured. In the second assessment, all subjects ran a timed, self-paced mile around a 200-meter track while wearing all three activity monitors. In the third assessment, thirteen subjects ran at five, six, seven and eight miles per hour on a motor driven treadmill for three minutes at each speed to assess the step counting reliability of the devices. The three devices were accurate to within 1% at all speeds on the treadmill and on the self-paced track run. In addition, all three devices were reliable (r = 0.80). Caloric expenditure estimation accuracy the NL-2000 was ± 21% when expressed in both net and gross kcals. The Digi-walker was f 22% when assumed to be net kcals and ± 45% when assumed to be gross kcals. The Actigraph was accurate to ± 49% in terms of net calories. The results of the current study have shown that these devices are accurate and reliable for step counting at speeds between five and eight mph. However, their ability to assess caloric expenditure is not accurate at the same speeds. In conclusion, the application of these devices to runners is limited to highly accurate and reliable step counters. / School of Physical Education, Sport, and Exercise Science

The purpose of this study was to examine the differences between international certification standards for ice hockey helmets. The American Society for Testing and Materials (ASTM), Canadian Standards Association (CSA) and International Organization Standards (ISO) protocols were compared. Only the impact testing methods at ambient temperatures were examined. Four helmet models, currently available to consumers, were used for testing. No significant differences (p $<$ 0.05) were found between the standards in a rank order comparison. Further analysis of differences, with peak linear accelerations separated by impact locations showed significant differences (p $<$ 0.05) between all standards, at five of the six defined impact sites, with no differences being found between standards at the rear site. Post-hoc pairwise multiple comparisons also showed significant performance differences (p $<$ 0.05) between helmet models.

Graduation date: 1953

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 94-96). / xv, 96 leaves, bound ill. 29 cm

"Work carried out by the author between March 1953 and January 1957 as a member of the Biophysics Group of the Physics Department of the University of Adelaide."--Pref. / "December 1957." / Includes bibliographical references (leaves 131-135) / vii, 135 leaves : ill. ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1957

"February 1955." / Includes bibliographical references (leaves 118-122) / 122 leaves : ill. ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Object of this project has been the establishment of a crystallographic laboratory sufficiently complete to enable a crystal structure analysis to proceed from the initial inspection of the crystal to the final presentation of electron density data in a two dimensional projection form. Parabanic acid was selected for the first analysis. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics, 1955

The EPID (electronic portal imaging device) was designed for in vivo imaging of patients during radiotherapy treatment. The ability of EPIDs to promptly acquire two dimensional data, lends them to be considered for use in quality assurance of the linac. This thesis set out to investigate the possibility of using a radionuclide, technetium 99 m (Tc99m), to produce a flood field for the calibration of an EPID, because using a beam calibrated EPID to measure the beam is self-referential. The difference in relative response between the energy spectrum of a 6MV beam and the Tc99m was investigated using EGSNRC DoseXYZ Monte Carlo Modelling. The relative output ratio was calculated to be less than 1.6%. The dose response of the EPID with respect to dose rate was checked using different activities of Tc99m and found to be linear. The flatness from a phantom was calculated, with a model in MATLAB, for a range of heights, overlaps, thickness, and deformations, to find the optimum balances between signal strength and flatness. This model was checked for accuracy using diagnostic radiographic film. The culmination of the energy response, linearity and the calculated flatness is a flood field taken with a flood phantom on the EPID with low signal strength. To get a signal to noise ratio of 3% the mean of over 2000 flood field images were used. This accuracy was not adequate for clinical use but the averaging of pixels it is accurate enough for QA.

Thesis (M.S.)--Edinboro University of Pennsylvania, 2007. / Typescript, photocopy. Includes bibliographical references (l. 16-17).

Mémoire (M.P.M.O.)--Université du Québec à Chicoutimi, 1990. / Document électronique également accessible en format PDF. CaQCU

Thesis (M.B.A.)--University of Hong Kong, 1995. / Includes bibliographical references (leaf 76).