• The Journal of the Acoustical Society of Korea
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• v.24 no.7
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• pp.371-378
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• 2005

The objective or this paper is to measure the in-plane vibration intensity of a beam with a damped end that means the magnitude and direction of vibration power. Three experimental methods have been implemented to measure the in-plane vibration intensity over the beam. The first method is the accelerometer array method using two accelerometers. The second method is the frequency response function method using the only one accelerometer. The third method is the reference accelerometer method using a fixed reference accelerometer and another moving accelerometer. Those methods have been used to measure the spatial distribution of in-plane vibration intensity over the beam. The results obtained with those methods have been compared with each other. The results have been compared with an input power. It showed that the frequency response function method and the reference accelerometer method as well as the accelerometer array method can be effectively used to measure the in-plane vibration intensity in beams.

• Journal of Advanced Navigation Technology
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• v.24 no.2
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• pp.128-133
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• 2020

In this study, an 1-dimensional positioning method using iterative linear regression for path loss expression is proposed. In the proposed method, received signal strengths (RSS) measured in several locations and distances between the measuring locat ions obtained by dead reckoning are used to derive a linear regression for the path loss from the transmitting beacon. In the proposed method, for the distance between the transmitting beacon and a target measuring location, several tentative values are assumed. For each tentative value, a linear regression is obtained. Among the linear regression expressions, the one closest to the known reference RSS value is selected and used to derive the distance to the target location. Test results show that the proposed method is more accurate than path loss model.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.179-185
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• 2020

Recently, in order to improve the performance of the Earthquake Early Warning System (EEWS) and to supplement the effects of earthquake disaster prevention in epicenters or near epicenters, development of on-site EEWS has been attempted. Unlike the national EEWS, which is used for earthquake disaster prevention by using seismic observation networks for earthquake research and observation, on-site EEWS aims at earthquake disaster prevention and therefore requires efficient design and evaluation in terms of performance and cost. At present, Korea lacks the necessary core technologies and operational know-how, including the use of existing EEWS design criteria and evaluation methods for the development of On-Site EEWS as well as EEWS. This study proposes hardware and software design directions and performance evaluation items and methods for seismic data collection, data processing, and analysis for localization of On-Site EEWS based on the seismic accelerometer requirements of the Seismic and Volcanic Disaster Response Act.