• Geophysics and Geophysical Exploration
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• v.14 no.3
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• pp.254-260
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• 2011

We studied magnitude determination method using high-frequency energy radiation duration to calculate rapidly magnitude of large earthquakes that occurred around Japan. Fourteen earthquakes were analyzed using Korea Meteorological Administration (KMA) data. We calculated duration of high-frequency energy radiation with 2~4 Hz band pass filter at each data and estimated magnitude. As a result, duration becomes longer as magnitude becomes larger and the magnitude estimated using regional earthquake data are similar to that using teleseismic data. Therefore when an earthquake occurs around Japan we will be able to estimate the magnitude in a relatively short time using KMA data and it may be possible to determine if the earthquake is large enough to produce tsunami.

• The Journal of the Korea Contents Association
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• v.9 no.4
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• pp.228-235
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• 2009

As we recognize the health care, test of BMD is increased. There are various methods in BMD, Dual Energy X-ray absorptiometry (DEXA) which has high precision and accuracy, and low medical exposure dose has been widely used. To measure the changes of BMD, the test must be done as same posture at first and follow up study performed a year. we analyze the difference in the hour taken before and after the examination by radiologic technologist, frequency of scout scan, and the amount of the radiation exposure. The hour of the examination and frequency of the scout scan were shorten and the dose of the radiation exposure is reduced. As the numerical value of total subjects is converted into that of one person, the duration for the test was 52 seconds, the frequency for the scout scan 0.79 time, and the dose for the radiation exposure $13{\mu}Sv$. When the health care provider perform the precise and easy methods to minimize changes of posture and the skillful ability to manage the test, useless radiation is decreased.