Sendust를 이용한 휴대전화용 전파 흡수체의 개발

최정현,김동일,송재만,정재현,Choi Jung-Hyun,Kim Dong-Il,Song Jae-Man,Jung Jae-Hyun 한국전자파학회 2005 한국전자파학회논문지 Vol.16 No.8

본 논문에서는 시편의 두께와 $Al_2O_3$ 함유량, 분쇄시간에 따른 입자 크기가 Sendust를 이용한 sheet형 전파 흡수체 의 전파 흡수능에 미치는 영향을 조사한 것이다. $Al_2O_3$를 코팅한 전파 흡수체는 코팅하지 않은 전파 흡수체와 비교할 때 흡수 대역이 넓어지고, 분쇄 시간이 증가함에 따라 입자 크기가 작아지고 이로 인해 전파 흡수능이 증가함을 확인하였다. 제작된 전파 흡수체의 두께가 4 mm일 때 946 MHz에서 17.4 dB, 1 mm일 때 1.8 GHz에서 약 5 dB의 전파 흡수능을 나타내었다. In this paper, we fabricated sheet-type EM wave absorbers for mobile phones by using sendusts and tested EM wave absorption of it. The band-width of EM wave absorbers coated with $Al_2O_3$ were larger than non-coated EM wave absorbers. Particle size decreased with increasing milling time, which made the result of increasing of EM wave absorption. The fabricated EM wave absorbers show a reflection coefficient 17.4 dB at 946 MHz for a 4 mm sample and 5 dB at 1.8 GHz for a 1 mm sample.

대퇴네갈래근에 테이핑요법 적용이 근력과 근피로에 미치는 영향

최정현,이재갑,안호정,Choi, Jung-Hyun,Lee, Jae-Kap,Ahn, Ho-Jung 대한물리치료과학회 2008 대한물리치료과학회지 Vol.15 No.4

Background: This study examines the changes in muscular strength and muscle fatigue substances when taping treatment is applied in squat exercise and treadmill exercise, in which quadriceps femoris muscles are used frequently so as to clarify the effects of taping as an aid of exercise ability improvement. Methods: 20 healthy male adults in their 20's participated in the study, in which tapes were put on their quadriceps femoris muscles, and various variables as the indicator of muscular strength and muscle fatigue substances were measured by means of the measuring tool before and after exercises. Results: the following conclusion was drawn up: 1. In exercise using muscular strength of the right knee extension, the reduction of muscular strength after exercise of the taping group showed significant statistical difference from that of the non-taping group. 2. In exercise using muscular strength of the lower limbs, the reduction of blood Glaucos after exercise of the taping group showed significant statistical difference from that of the non-taping group. 3. In exercise using muscular strength of the lower limbs, the value of lactic acid after exercise of the taping group showed significant statistical difference from that of the non-taping group. Conclusion: Therefore, the results of this study demonstrate that the application of taping treatment in sports activity or daily life where quadriceps femoris muscles are used a lot can have positive effects on the improvement of muscular strength and relief of muscle fatigue.

Sn-Pb 솔더를 이용한 경연성 인쇄 회로 기판간의 열압착 본딩

최정현,이종근,윤정원,정승부,Choi, Jung-Hyun,Lee, Jong-Gun,Yoon, Jeong-Won,Jung, Seung-Boo 한국마이크로전자및패키징학회 2010 마이크로전자 및 패키징학회지 Vol.17 No.3

본 연구에서는 Sn-Pb 솔더를 이용한 열압착법을 이용하여 경성 인쇄 회로 기판 (rigid printed circuit board, RPCB)과 연성 인쇄 회로 기판 (flexible printed circuit board, FPCB)간 접합 시의 접합 조건을 최적화하는 연구를 진행하였다. 접합의 주요 변수로는 접합 압력, 온도 및 시간이 있으며 이러한 변수의 변화로 인해 접합부의 접합 형태와 박리 강도에서 많은 차이가 발생하는 것을 확인할 수 있었다. 또한 일정 접합 온도와 시간 조건 ($225^{\circ}C$, 7초)에서 22 N/cm의 최고 박리 강도를 보이며 이후로는 더 이상 박리 강도에서 큰 차이를 보이지 않게 되는데, 이를 박리 시험 시의 F-x (forcedisplacement) curve를 토대로 파괴 에너지를 산출하여 그 차이를 규명하였다. 최적의 접합 조건은 $225^{\circ}C$, 7초로 나타났다. In this paper, we focused on the optimization of bonding conditions for the successful thermo-compression bonding of electrodes between the RPCB and FPCB with Sn-Pb solder. The peel strength was proportionally affected by the bonding conditions, such as pressure, temperature, and time. In order to figure out an optimized bonding condition, fracture energies were calculated through F-x (force-displacement) curves in the peel test. The optimum condition for the thermo-compression bonding of electrodes between the RPCB and FPCB was found to be temperature of $225^{\circ}C$ and time of 7 s, and its peel strength was 22 N/cm.

움직임 벡터 및 보상 블록의 특성을 이용한 움직임 보상된 차영상 CVQ

최정현,이경환,이법기,정원식,김경규,김덕규,Choi, Jung-Hyun,Lee, Kyeong-Hwan,Lee, Bub-Ki,Cheong, Won-Sik,Kim, Kyoung-Kyoo,Kim, Duk-Gyoo 대한전자공학회 2000 電子工學會論文誌-SP (Signal processing) Vol.37 No.2

본 논문에서는, 움직임 벡터와 보상 블록을 이용한 분류기를 제안하고, 이 분류기로써 MCD(motion compensated difference) 블록을 CVQ(classified vector quantization)하는 새로운 MCDI(motion compensated difference image) 부호화 방법을 제안하였다. MCD 블록의 분산은 움직임 벡터의 크기뿐만 아니라 보상 블록의 분산과도 밀접한 관계가 있으므로, 이 특성들을 이용하여, 새로운 분류기를 제안하였다. 제안한 방법은 서브 코드북(sub-codebook)을 선택하는 분류기에 대한 부가 정보가 필요 없으면서, 모의 실험 결과 분류 비트가 필요한 기존의 방법에 비해 제안한 방법이 좋은 성능을 나타내었다. In this paper, we presents a new MCDI(motion compensated difference image) coding method using CVQ(classifled vector quantization) whoes MCD(motion compensated difference) block is classified by proposed classifier using motion vector and compensated block The variance of MCD block is closely related with the magnitude of motion vector as well as the variance of compensated block, so using this property, we propose a new classifier. This scheme has no side information of the classifier what sub-codebook is selected, and simulation results show that the proposed method exhibits a good performance even when compared with a conventional method that requires classification bits.

천웅(天雄)의 포제에 관하여

최정현,정병하,성만준,권동렬,Choi Jung-Hyun,Jung Byung-Ha,Seong Man-Jun,Kwon Dong-Yeul 대한한의학방제학회 2004 大韓韓醫學方劑學會誌 Vol.12 No.1

Aconiti Root(AR), has been used for about 2000 years, since recorded for low grade in 'Shinnongbonchokyung(Divine Husbandman's Herbal Foundation canon)'. It also recorded for Poisonous Drug in 'Myunguibyullok', 'Yaksungron', etc, and they advised when the AR is using for clinical desease it has to be processed. There are more than 13 processing methods, in records that related 39 parts which is recorded in ancient documents. In China, there are no standard of herb that using for clinical, cause of the traditional processing methods was cut since 1960s. In these days, they are using AR that recorded in Aconiti Tuber part of the processing records, in Guangdong and Shantung. In addition, the modification of Processed Aconiti Root(PAR) is also used for goods in Hongkong, Macao, and Southeast Asia. We studied the PAR for enhancing the importance of it, and multiply using. In this study, we search for the history of processing of AR, traditional theories of processing and clinical adaptation.

움직임 벡터의 통계적 특성을 이용한 고속 움직임 추정

최정현,박대규,이경환,이법기,김덕규,Choi, Jung-Hyun,Park, Dae-Gyue,Lee, Kyeong-Hwan,Lee, Bub-Ki,Kim, Duk-Gyoo 대한전자공학회 2000 電子工學會論文誌-SP (Signal processing) Vol.37 No.2

고속 움직임 추정 방법들에서는, 움직임 추정 오차는 최적 탐색점에서 멀어질수록 단조 증가한다는 성질을 이용하여, 계산량을 줄인다 본 논문에서는 먼저, 참조 탐색점들의 MAE (mean absolute error) 차가 클 때에, 대부분의 움직임 벡터는 작은 MAE의 참조 탐색점 방향에서 나타난다는 통계적 특성을 조사하였다 그러므로, 이 특성을 이용하여 탐색점 수를 줄일 수 있는 고속 움직임 추정 방법을 제안한다 모의 실험 결과, 기존의 고속 움직임 추정 방법들에 비해서는 비슷한 성능을 유지하면서 계산량을 줄일 수 있었다. In Fast motion estimaion algorithms, they reduce the computational complexity using the assumption that the matching error increases monotonically as the search moves away from the global minimum error In this paper, we first investigate the statistical characteristics of motion vector that the motion vector mostly occures on the side of small MAE (mean absolute error) between the reference search points when the MAE difference of them is large Therefore, we propose a fast motion estimation algorithm using this property and can reduce the number of search points The computer simulation result shows that the proposed method reduces computational complexity compared with conventional fast algorithms.

키예프 루시의 "통일성"에 대하여

최정현 ( Jung Hyun Choi ) 한국러시아문학회 2012 러시아어문학 연구논집 Vol.39 No.-

팔당호 수질관리 정책의 효과 분석

최정현(Jung Hyun Choi),하주현(Joo Hyun Ha),박석순(Seok Soon Park) 大韓環境工學會 2008 대한환경공학회지 Vol.30 No.12

이 논문에서는 팔당호에 행해진 수질관리 정책의 효과를 분석하기 위하여 계절 맨-켄달 경향분석법(Seasonal Mann-Kendall Trend Analysis)을 사용한 새로운 접근법으로 팔당호로 유입되는 주요 지류중 하나인 경안천의 수질을 정책 전과 후로 나누어 비교 분석하였다. 1992년부터 2005년까지 월별로 측정된 BOD, COD, 총인 및 총질소의 자료들을 이용하여 1998년 한강특별대책 시행 전과 후의 켄달 기울기(Kendall slope)를 비교하였고, 그 결과 한강특별대책이 경안천 하류의 수질 개선에는 효과가 있었으나 상류의 수질 개선에는 큰 효과를 거두지 못하였음을 밝혀냈다. 이러한 결과는 이전에 행해진 경안천 수질 관련 연구들의 결과와 잘 일치하는 것으로 보아, 이 연구에서 사용된 수질의 장기 경향 분석을 통한 정책의 효과를 판단하는 접근법은 앞으로 유용하게 사용되어 질 수 있으리라 판단된다. A new approach based on the Seasonal Mann-Kendall Trend Analysis, was presented in this paper, in order to estimate effect of water quality management policy in Kyoungan Stream which is one of major tributaries into the Lake Paldang. The estimation was undertaken by comparing water quality trend slopes before and after implementation of the policy. The monthly water quality data of Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Nitrogen (TN) and Total Phosphorus (TP) measured from 1992 to 2005, were analyzed to determine the Kendall slopes before and after the Han River special policy implemented at 1998. The results indicated that the 1998 special policy would be effective in water quality improvement not at upstream but at downstream. This result agrees well with the previous water quality studies at Kyoungan stream. It was suggested that the presented approach could be an useful tool to estimate effect of a water quality management policy.

산모의 직업활동이 태아, 신생아 및 분만방법에 미치는 영향

최정현(Jung-Hyun Choi),장재선(Jae-Seon Jang),김성철(Sung-Chul Kim) 한국콘텐츠학회 2012 한국콘텐츠학회논문지 Vol.12 No.1

2010년 1월에서 2010년 12월까지 경기도 광명 소재 산부인과에서 초진에서부터 분만까지 동일 병원에서 실시한 산모 중 37주 이후에 정상 분만한 141명(비직업인군 73명과 직업군 68명)을 대상으로 태아, 신생아체중 및 분만방법을 산모의 직업여부에 따라 비교 분석하여 보았으며, 다음과 같은 결과를 얻었다. 1. 임신후 37주 기간의 산모체중 및 평균임신기간은 통계적인 차이는 없었다. 2. 37주시 태아체중은 비직업군은 평균 2.90±0.27 kg, 저체중아 비율은 2.75%, 직업군에서는 평균 2.76±0.28 kg, 저체중아 비율은 10.3%로 나타나 비직업군에서 37주 태아체중이 유의하게 높게 나타났다(p<0.05). 3. 신생아체중은 비직업군은 평균 3.42±0.43 kg, 직업군은 3.18±0.35 kg으로 비직업군의 신생아체중이 유의하게 높게 나타났다(p<0.05). 4. 분만방법은 비직업군에서 제왕절개수술이 32.9%, 직업군에서는 16.2%로 비직업군에서 통계적으로 유의하게 많게 나타났다(p<0.05). This study compared and analyzed fetus, newborn infant, and delivery methode of 141 women who received medical service from the first examination to the delivery in an obstetrics and gynecology specialized hospital located in Gwangmyeong, Gyeonggi-do from Jan. 2010 to Dec. 2010 and had a regular delivery after 37 weeks of pregnancy (73 non-employed and 68 employed women), depending on employment state of the subjects. The following are the results derived from the study. 1. The weight of the mothers after 37 weeks of pregnancy and the average gestational age was no statistical difference depending on the employment state. 2. In 37 weeks, the average fetal weight in the non-employed group was 2.90±0.27 kg and the rate of small for gestational age infants was 2.75%. Meanwhile, the average fetal weight in the employed group was 2.76±0.28 kg and the rate of small for gestational age infants was shown to be 10.3%. It is known that the fetal weight of the non-employed group was significantly higher for 37 weeks of pregnancy (p<0.05). 3. The newborn infant weight of the non-employed group was 3.42±0.43 kg in average while that of the employed group was 3.18±0.35 kg. It is known that the newborn infant weight of the non-employed group was significantly higher (p<0.05). 4. In terms of delivery method, cesarean constituted 32.9% in the non-employed group while constituting 16.2% for the employed group. It is known that cesarean was shown to be significantly higher among the non-employed group (p<0.05).

뇌허혈 유발 후 전침자극이 전뇌세포사 중 Bax와 Caspase-3 발현 변화에 미치는 영향 연구

최정현 ( Jung Hyun Choi ),민경옥 ( Kyoung Ok Min ),김순희 ( Soon Hee Kim ),김동일 ( Dong Il Kim ),이상빈 ( Sang Bin Lee ),안호정 ( Ho Jung An ),김지성 ( Ji Sung Kim ),최완석 ( Wan Suk Choi ),김보경 ( Bo Kyoung Kim ),송치원 ( Chi W 대한한방신경정신과학회 2010 동의신경정신과학회지 Vol.21 No.1

Objectives: The study aims to look into how the application of EA(Electro-acupuncture) in the initial step of ischemic brain injury affects the changes in Bax and Caspase-3 expression among forebrain apoptosis. Methods: It caused GI by using common carotid artery occlusion and conducted the test by dividing into the no applied EA group after 6 hours and 12 hours, the LI 4 EA group that applied EA to LI 4, and GV 20 EA group that was applied to GV 20. After that, the following results were obtained by comparing Bax and Caspase-3 expression, which were apoptosis-related factors, with its application time through immunohistochemical staining after extracting brain of each group. Results: According to each group`s Bax expression by the application time, the order of expression increase after 6 hours is shown to be the no applied EA group, LI 4 group, and GV 20 group. The stimulation after 12 hours was most lowly expressed in the GV 20 group, and the no applied EA group and LI 4 group showed similar level. Conclusions: EA stimulation in the initial step after ischemia seems to affect positively Bax and Caspase-3 expression that are index of forebrain apoptosis.