• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.201-203
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• 2009

This paper presents the real time stray current monitoring techniques on the DC railway system. These techniques are two types. The first one is the rail potential measurement technique between running rail and earthing mats on the important locations such as substation, station, and so on. And the second one is measurement technique of stray current through substation earthing mats and from collection mats, and continuous monitoring of return currents through the running rails. We need to apply these techniques on DC railway system to monitor stray current periodically and maintain the system properly.

• Journal of Environmental Health Sciences
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• v.46 no.1
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• pp.103-109
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• 2020

Objectives: Using as a sleep evaluation tool the Pittsburgh Sleep Quality Index (PSQI), this paper studied the effects of earthing on the amount and quality of sleep by examining a patient population of people who used and did not use earthing mats and a group of general healthy people. Methods: From September to November 2019, 30 patients who voluntarily used an earthing mat, 40 patients who did not use an earthing mat, and 40 healthy people who did not use an earthing mat were selected. A questionnaire applying the PSQI (Pittsburgh Sleep Quality Index) after being translated into Korean was distributed starting November 29, 2019 to 110 subjects. Out of them, 101 subjects who completed the questionnaire were examined. All statistics used SPSS 25.0. Results: The first overall score showed that all three groups had problems sleeping, with five points or more, but the general population had better sleep quality than the patient group. It also showed that the using matgroup had better quality of sleep than the ones that did not use the earthing mat In addition, the analysis of the third group through the variance analysis showed significance at >0.05 for the general population and the patient group. Based on this, a multi-comparison analysis of the third group showed significantly less than 0.05 in patients who do not use an earthing mat compared to the public. First of all, there are no statistically significant differences between the three groups in subjective sleep quality, sleep latency, and sleep time, but an analysis of multiple comparison analysis with the general population group showed that the quality of sleep was worse compared to those that used the mat. In addition, sleep efficiency, sleep disorder, sleeping pills, and daytime dysfunction were found to be less than >0.05 in the three groups. Conclusions: These results suggest that if you ground your body to Earth during sleep, the secretion of cortisol will decrease night levels, sync more with the natural 24-hour circulation rhythm profile, and that when you sleep, sleep is better and pain and stress are associated with the study. While the preceding study cannot confirm that contact with the ground affects the quality of sleep, it suggests that it is relevant as shown in this paper.