• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.369-370
• /
• 2009

전력선 통신용 접촉식 커플러의 제조 방법 확립과 응용 가능성을 파악하기 위해 440V이하의 저압용 3상 4선식 접촉식 커플러를 설계 및 제조하였다. 60Hz의 교류 전압 신호를 차단하는 캐패시터의 용량이 증가할수록 삽입 손실의 증가하였으며, 68nF의 캐패시터를 적용하여 90~450kHz, 2~30MHz의 전력선통신 주파수 대역에서 최소 삽입 손실 특성을 얻었다. 커플링 트랜스의 권선수 증가는 전자계 결합계수의 상승으로 자기유도 효율이 증가하여 삽입 손실 특성이 증가하였으며. 6턴 이상의 권선수에서는 거의 일정한 삽입 손실 특성을 나타내었다. 설계 완료된 접촉식 커플러를 이용하여 전력선 통신 주파수인 90~450kHz, 2~30MHz 대역에서 $-2\pm1dB$의 삽입 손실 특성을 얻었다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.17 no.1
• /
• pp.21-31
• /
• 2005

In this study, derivation is made of a one-grid source function for the extended Boussinesq equations of Nwogu (1993) in order to generate nonlinear waves internally. The energy velocity approach used in the line source method is verified analytically by the fractional step splitting method. The source function method is verified by generating accurately nonlinear waves as well as linear waves for horizontally one-dimensional cases. It is found that numerical solutions by the source function method are the same as those by the line source method.

• Korean Journal of Plant Tissue Culture
• /
• v.26 no.4
• /
• pp.265-269
• /
• 1999

Transgenic tobacco plants expressing either a sweet potato anionic peroxidase (POD) (swpal) or neutral POD (swpnl) were irradiated by gamma radiation, and the gamma radiation-induced biochemical changes in antioxidant enzymes and plant growth inhibition were investigated at 30 days after treatment. Gamma radiation significantly inhibited the growth of all plants regardless of transgenic or nontransformed plants, showing a dose-dependent inhibition. In high dosage of 50 and 70 Gy, plant heights were severely retarded and new leaves does not emerged. No significant changes in antioxidant enzymes such as POD, superoxide dismutase and catalase were observed in all plants regardless of irradiation dosages ranging from 10 to 50 Gy. These results suggest that sweet potato PODs may be not involved in the protection against the oxidative stress induced by gamma radiation.

• Electric Engineers Magazine
• /
• v.228 no.8
• /
• pp.43-48
• /
• 2001

Wide use of non-linear loads such as personal computers, monitors, laser printers, variable speed drives, UPS systems and other electronic equipment have led to harmonics becoming #1 issue in the electrical industry today. Commercial and Industrial building power distribution systems, designed for the old, linear-style loads especially when found in high densities. Some common power system problems include overloaded neutral conductors, overheated distribution transfOlmers, high neutral-to-ground voltage, poor power factor and distortion of the voltage waveform supplying these loads. The power quality problems, particularly high voltage distortion, have been known to cause equipment downtime due to malfunctions and component failure.

• 한국HCI학회:학술대회논문집
• /
• 2008.02a
• /
• pp.158-162
• /
• 2008

Heart rate has many effect by environment factor and body factor and mind factor. Experimental testing decide to make relaxed condition. so It want to get correct data peoples different time and condition in the day so medical mans think relaxed to low Heart rate. but normal heart different from peoples and time. there was noting standard. so Heart rate is really hard to relaxed heart rate. Heart rate pattern must have long time analysis for good result. if you get relaxed heart rate so you don't need long-time analysis. Relaxed heart pattern used for guidance of auditory impulse public got concentration and solve to stress. it chose MC Square and mozart music. Two kind of auditory impulse analysis to make a relaxed Heart rate and relaxed pattern. way of analysis is HRV and minute of heart bit rate. result It have find Guidance to Relaxed Heart rate.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.29 no.2
• /
• pp.114-121
• /
• 2009

Ultrasonic guided waves have been widely utilized for long range inspection of structures. Especially, development of array guided waves techniques and its application for long range gas pipe lines(length of from hundreds meters to few km) were getting increased. In this study, focusing algorithm for array guided waves was developed in order to improve long range inspectability and accuracy of the array guided waves techniques for long range inspection of gas pipes, and performance of the developed techniques was verified by experiments using the developed array guided wave system. As a result, S/N ratio of array guided wave signals obtained with the focusing algorithm was increased higher than that of signals without focusing algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.1
• /
• pp.125-130
• /
• 2007

Single-phase is used widely power of field of appliance because can use commercialized power directly without power transform. Specially, because condenser nu-drive style single-phase induction motor efficiency is excellent, and most suitable in embodiment as economical. It is established true that method by crossing self-discipline and method by revolving magnetic field are interpretation of net single-phase induction motor, but method to calculate electric motor inside proper move in existent theory or method is some complex. That arbor in the law of circuit constant that combine equivalent circuit law with numerical analysis law according to development of the latest computer or microprocessor is suggested and does the calculation processing fast and correct. In this paper, measurement wishes to present method that calculate after calculate digital measurement that measures correctly and measures impossible the first and the second leakage reactance and no-load test locked-rotor test, DC test and resistance measurement of stator winding in circuit parameter calculation program that is had for MatLab program individually in single-phase power.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2013.05a
• /
• pp.500-502
• /
• 2013

The metallic underground pipes like as metropolitan water supply pipes and gas pipes have a screening effects for power induction phenomenon. Generally, urban area has more metallic underground facilities than rural areas because of its buildings or population density. So we can expect high screening effects for the power induction in urban areas, and we call it the city screening factor. We had carried out the measuring test in urban and rural area respectively 30 sites to prove the actual effects of city screening factor and we derived the numerical value of city screening effects. But we faced with a difficult question that how we can classify the real urban areas or rural areas correctly. In this paper, we introduce the classification method using density of building in test area to apply the city screening factor reasonably.

• The Journal of the Korea Contents Association
• /
• v.20 no.3
• /
• pp.661-670
• /
• 2020

The purpose of this study was to investigate the incidence of sports injury and trend of incidence pattern of national judo athletes. The research method was analyzed based on the records of all injuries experienced by national judo athletes during training and competition for 9 years from 2008 to 2016. A total of 20,345 sports injuries requiring physical therapy were 10,768 (52.93%) for women, 9,577 (47.07%) for men, lower extremities 9,688 (47.62%), upper limbs 5,807 (28.54%), and trunk 4,850 (23.84%) and knee-related injuries (27.82%) occur more frequently than other injuries. Shoulders, feet and back were more frequent in male athletes, and ankle, neck and hand injuries were more common in female athletes. Using the binomial trend line, the trend of the decrease of sports injuries in each area was shown. However, infrequent injuries such as hands and hips tend to increase gradually. The results of this study are expected to be used as a training program for judo athletes' sports injury and basic data.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.37C no.12
• /
• pp.1211-1221
• /
• 2012

This paper describes separation distance to protect radiocommunication services from the interference of inductive systems using frequencies below 30 MHz for the co-existence between radiocommunication services and inductive systems. For the analysis, the interference scenario model is proposed between inductive system and radiocommunication services. Then the calculation method of protection distance is suggested by comparing the radiation power of inductive system with the allowable interference level of victim services, radiocommunication services, according to the applied propagation model. Also, the protection distance for protecting radiocommunication services in the 30 MHz below is calculated through the interference analysis from RFID(Radio Frequency IDentification) and PDP(Plasma Display Panel) TV based on the suggested method. The proposed calculation method was adopted as ITU-R recommendation in related with resolution 63 at ITU-R SG(Study Group) 1 meeting in June, 2012. It will be available to use for the protection of radiocommunication services from the interference of wireless power transfer system and power line telecommunication system.