• 한국안전학회지
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• 제12권2호
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• pp.70-79
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• 1997

This paper presents a study on the fuzzy linguistic variable based approach for safety assessment of human body in ELF electromagnetic field considering power system states. To cope with the demand in modern industry, the power system becomes larger in scale, higher in voltage. The advent of high voltage system has increased the relative importance of field effects. The analysis of ELF electromagnetic field based on Quasi-Static Method is introduced while the power system is included to model the expected and/or unexpected uncertainty caused by the load fluctuation and parameter changes. In order to analyze the power system, Monte Carlo simulation method and contingency analysis method are adopted in normal state and alert state, respectively. In the safety assessment of human body, the approach based on fuzzy linguistic variable is employed to overcome the shortcomings resulting from a crisp set concept. The suggested scheme is applied to a sample system(modified IEEE 14 bus system) to validate the usefulness.

• 한국전자파학회논문지
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• 제23권2호
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• pp.251-257
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• 2012

인체 통신이란 사람의 몸통이나 피부를 전송 매질로 하여 데이터를 송수신하는 통신 방식을 의미한다. 본 논문에서는 인체 피부 표면에 닿아 있는 자유 공간을 전송 매체로 하여 데이터를 전달하는 전송 방식에 대하여, 10~30 MHz 주파수 범위에서 5 MHz 간격으로 5개의 주파수에 대하여 송수신부 사이의 전기장 분포에 대하여 수치 해석하였다. 채널 손실 계산은 총 29종의 조직으로 구성되어 있는 한국형 남성 표준 인체 모델에 상용의 툴을 사용하여 실행하였다. 계산 주파수에 따른 인체 조직의 도전율과 비유전율을 해석 파라미터로 입력하여 송수신부로 간주되는 손등 위에서 전기장 분포를 계산하였다. 손등에 부착된 송신기에 의한 전자파비(比)흡수율(SAR: Specific Absorbtion Rate) 값을 계산한 후, 국제비전리복사방호위원회(ICNIRP: International Commission on Non-Ionizing Radiation Protection) 인체 보호 기준과 비교하였다. 또한, 수치 해석으로 구한 전기장을 선(線)적분하여 인접한 극판들 사이의 전압들을 계산하였고, 송신부와 수신부의 전압의 비(比)를 채널 손실로 정의하였다. 수치 해석 결과, 10~30 MHz 주파수 대역에서 채널 손실의 범위는 약 ($75{\pm}1$) dB로 주파수에 따른 채널 손실의 변화가 크지 않았다.

• 한국안전학회지
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• 제36권4호
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• pp.20-28
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• 2021

With an increase in the commercialization of electricity, and the development of advanced and large electric devices and various wireless radio wave services, concerns over the effects of electromagnetic fields on human health have increased. Accordingly, the World Health Organization encouraged the development of international standards by establishing the 'International Electromagnetic Fields Project' in 1996 based on studies on the harmful effects of electromagnetic fields on the human body. Moreover, the National Institute of Environmental Health Sciences (NIEHS) classified electromagnetic fields as possible carcinogens under Group 2B category, even though they have been found to have a weak correlation with those effects on human health. Mid-to-large-sized electric facilities used at industrial sites mostly adopt a commercial frequency of 60 Hz, and workers handling these facilities are exposed to such extremely low frequency (ELF) fields for a long time. A previous study suggested that exposure to ELF electromagnetic fields with frequency ranges from 0 to 300 Hz, even for a short time, at densities higher than 100 μT may have harmful effects on human body as it affects the activation of nerve cells in the central nervous system by inducing an electric field and current and stimulating muscles and the nervous system in the body. Such studies, however, focused on home appliances used by ordinary people, and research on facilities utilizing high-capacity current and operated by workers at industrial sites is lacking. Therefore, in this study, a 3000 kilowatt generator, which is a high-capacity electric facility employed at industrial sites, was investigated, and the size of the magnetic fields generated during its no-load and high-load operations per distance to produce a map was measured to reveal spots deemed hazardous according to domestic and international exposure standards. The findings of this study is expected to alleviate workers' anxiety about the harmful effects of magnetic fields on their body and to minimize the level of exposure during operations.

• Journal of Magnetics
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• 제19권2호
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• pp.174-180
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• 2014

In this paper, a new and simple method is proposed to quickly estimate the induced electric field in the human child exposed to a 100 kHz-10 MHz magnetic field, for the sake of electromagnetic field (EMF) safety assessment. The quasi-static finite-difference time-domain (FDTD) method is used to calculate the induced electric fields in high resolution 3D human child models with various body size parameters, in order to derive the correction factor for the estimation equation. The calculations are repeated for various frequencies and incident angles of the magnetic field. Based on these calculation results, a new and simple estimation equation for the 99th percentile value of the body electric field is derived that depends on the body size parameters, and the incident magnetic field. The estimation errors were equal to or less than 5.1%, for all cases considered.

• 한국안전학회지
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• 제14권3호
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• pp.54-62
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• 1999

This paper presents a study on the safety assessment of human body for electromagnetic field at unbalanced power system. The 3-phase load flow algorithm uses Newton-Raphson method based on Taylor series expansion of power flow equations in rectangular coordinates. The use of such a method can result in a solution with good convergence characteristics. In the safety assessment of human body, the approach based on fuzzy linguistic variable is employed to overcome the shortcomings resulting from a crisp set concept. The suggested scheme is applied to a 24bus system to validate the usefulness. The results for an unbalanced power system are compared with the results for a balanced power system.

• 스마트미디어저널
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• 제5권3호
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• pp.49-53
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• 2016

인체 전자기장 신호를 검출하여 동작 인식에 이용하는 비접촉방식의 방법은 시간과 공간의 제약이 기존의 시스템보다 덜하므로 관련 연구들이 진행 중에 있다. 본 논문에서는 비접촉방식의 인체전기장 신호를 검출할 수 있는 하드웨어를 구현하여 이를 디지털 파형화 하여 인식률을 높일 수 있는 회로시스템을 설계하였다. 차동 증폭회로의 구현과 비교기를 연동한 디지털 파형화를 위한 회로 시스템을 시뮬레이션과 결합하여 PCB화한 후/ 설계된 전체 회로 시스템에 대한 특성평가를 수행하였다.

• 한국안전학회지
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• 제8권3호
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• pp.34-43
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• 1993

This paper presents a study on the characteristics and safety criteria for human body in ELF (Extremely Low Frequency : 50-60Hz) electric and magnetic fields. Many researches for ELF electric and magnetic fields, which are developed in the past, are studied and analyzed In this paper. In order to estabilish the safety criteria for human body in the field, the field intensity, induced current and voltage are calculated by the electrostatic field approach which is far simpler than the electromagnetic field one based on Maxwell equation. The method is applied to the 345 KV transmission line system In operation and 765 KV system under consideration. According to the results, the maximum value of field intensity, 6.8627KV/m, is evaluated at the location which is 14m away from transmission line. As the safety criteria value by the abroad researches asserting that the human can detect the Induced current in 6KV/m and above, 5KV/m and 7KV/m are recommended at residence area and nonresidence area, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 E
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• pp.1648-1650
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• 1997

The effects of power frequency electric and magnetic fields have been a source of concern for many years. Electromagnetic fields can pose a theat to both signal system of electrified railways and human body around railways. It is believed that, though the electromagnetic fields do no serious harm to human health, they do induce biological effects. This paper estimates the electromagnetic fields near Kyeongbu high speed railways with numerical data. The charge simulation method and surface charge method are used to calculate the electric field of 2 dimensional power distribution lines and rails and magnetic field is calculated on the base of Biot-Sarart's law.

• 조명전기설비학회논문지
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• 제27권2호
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• pp.110-119
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• 2013

As the technologies such as middle-range resonant WPT (wireless power transfer) advance that utilizes medium and low-frequency magnetic field, the importance of safety of such magnetic field is growing. The research on the effect of electromagnetic field on the human body has been mainly done on the GHz range of mobile phones, or 50~60Hz range of electric power systems. However, there has been relatively few works on the 100kHz~10MHz range used in the resonant wireless power transfer. Since there is a difference in the limiting value of magnetic field between widely used ICNIRP EMF guideline and IEEE C95.1 standard, there can be possible confusion when establishing EMF (Electromagnetic Field) standard on the wireless power transfer device in the future. In this paper, the induced current in the human body, which is the basic restriction of the EMF guideline, is calculated using Quasi-static FDTD method when 3D high-resolution human model is exposed to the 100kHz~10MHz magnetic field. Using this result, the feasibility of the magnetic field reference level in the ICNIRP guideline is analyzed.

• 한국전자파학회논문지
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• 제20권6호
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• pp.503-508
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• 2009

전자파의 사용 범위가 확대되고 각 분야에서의 활용도가 높아짐에 따라 인체에 대한 영향이 증가하여 이에 대한 많은 연구가 이루어지고 있다. 하지만 인체의 영향 연구나 인체 보호 기준이 단말기에 의한 영향은 SAR(Specific Absorption Ratio)의 연구 및 표준 활동이 활발하나 단파(high frequency) 대역에 의한 인체 유도 전류에 대한 연구는 미흡한 편이다. 본 연구에서는 근거리장에서 단파 대역 RFID 리더 안테나에 의한 인체에 유도되는 전류를 측정하고 이를 등가화 할 수 있는 수직 교차 루프 형태의 인체 등가 모형을 제시하여 인체의 유도 전류량과 비교하였다.