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Earthquake Engineering Research - HKU Libraries - The University ...

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554<br />

were observed in the vision-system positional data requiring frequency domain filtering: (1) that<br />

imposed artificially from the reaction floor in the laboratory and (2) that imposed during numerical<br />

differentiation due to time stepping. Using low-pass filtering techniques, reasonable acceleration and<br />

velocity time histories were generated. <strong>The</strong> largest difference in maximum accelerations and velocities<br />

observed was fairly reasonable at 0.06g's and 6 cm/second, respectively.<br />

<strong>The</strong> initial comparison of measurements obtained from the vision-based system and conventional<br />

sensors in this study provides promising results for the use of such systems in future experimental<br />

earthquake research. Further study is required to evaluate the applicability of these types of systems for<br />

capturing seismic motions in 3-dimensions, including the potential effects of occlusions during the<br />

time-variant capture process.<br />

ACKNOWLEDGEMENTS<br />

<strong>The</strong> experimental data from the study of Dr. Roberto Villaverde are greatly appreciated. <strong>The</strong> assistance<br />

of Mr. Charlie Hamilton and Mr. Bob Kajanzy of the Structural <strong>Engineering</strong> Test Hall (SETH) at UC<br />

Irvine is greatly appreciated.<br />

REFERENCES<br />

Cappozzo, A. (1984). "Gait analysis methodology." Human Movement Science. Vol. 3: 27-50.<br />

Faugeras, 0. (1993). Three Dimensional Computer Vision: a Geometric Viewpoint. MIT Press.<br />

Hansen, A.H., Childress, D.S., and Meier, M.R. (2002). "A simple method for determination of gait<br />

events." Journal ofBiomechanics. Vol 35: 135-138.<br />

Heyn, A., Mayagoitia, R.E., Nene, A.V., Veltink, P.H. (1996). "<strong>The</strong> kinematics of the swing phase<br />

obtained from accelerometer and gyroscope measurements." In the Proceedings of the 18 th Annual<br />

International Conference of the IEEE <strong>Engineering</strong> in Medicine and Biology Society. Amsterdam, pp.<br />

463-464.<br />

Kidder, S.M., Abuzzahab, F.S., Hams, G.F. (1996). "A system for the analysis of foot and ankle<br />

kinematics during gait." IEEE Transactions on Rehabilitation <strong>Engineering</strong>. Vol. 4(1): 25-32.<br />

Motion Analysis (2002). http-//www.motionanalysis.cnrn.<br />

Sampath, G., Abu-Faraj, Z.O., Smith, PA. and Harris, G.F. (1998). "Design and development of an<br />

active marker based system for analysis of 3-D pediatric foot and ankle motion." In the Proceedings of<br />

the 2V h Annual International Conference of the IEEE <strong>Engineering</strong> in Medicine and Bioloey Society<br />

Vol 20(5): 2415-2417.<br />

Vicon (2002). http://www.vicon.com.<br />

Villaverde, R., Aguirre, M. and Hamilton, C. (2002). "Roof isolation system implemented with steel<br />

oval elements: exploratory study." Proceedings of the 3 rd World Conference on Structural Control,<br />

Como, Italy. April 7-12.

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