[Hyun-seok Oh] 이미지로 세상을 편집하기

오현석(Hyun-seok Oh) (주)월간사진 2024 월간 사진 Vol.671 No.-

와이블 분포를 이용한 에폭시 복합체의 수명시간 예측

오현석,이동규,장인범,박건호,김용주,이준웅 ( Hyun Seok Oh,Dong Kyoo Lee,In Bum Jang,Geon Ho Park,Yong Ju Kim,Joon Ung Lee ) 한국전기전자재료학회 1997 한국전기전자재료학회 추계학술대회논문집 Vol.1997 No.1

최근 국내 분리 고병원성 infectious bursal disease virus의 segment A 유전자 특성

오현석,이진화,권혁무,성환우,Oh, Hyun Seok,Lee, Jin Hwa,Kwon, Hyuk Moo,Sung, Haan Woo 대한수의학회 2011 大韓獸醫學會誌 Vol.51 No.1

Infectious bursal disease virus (IBDV) is a member of the Avibirnavirus genus of the Birnaviridae family which genome consists of two segments (A and B) of double stranded RNA. Segment A gene of KNU08010 isolate, which was isolated from a 15-day-old chicken flock in 2008, was sequenced and compared with other IBDV isolates including SH/92 strain, the first Korean very virulent (vv) IBDV isolate. The amino acid sequences of segment A gene showed that KNU08010 had 99.2% homology with SH92 strain. KNU08010 isolate had specific amino acids A222, I242, I256, I294 and S299 which are highly conserved among vvIBDV strains. Phylogenetic analysis based on the nucleotide sequences of variable region of the VP2 gene of 18 IBDV strains revealed that KNU08010 was grouped with vvIBDVs and was closely related to Korean vvIBDVs isolated from wild birds.

CD 스터드 용접의 해석 및 결함 분석 Part 1 : 공정 모델링과 해석

오현석,유중돈,Oh Hyun-Seok,Yoo Choong-D. 대한용접접합학회 2006 대한용접·접합학회지 Vol.24 No.3

The CD (Capacitor Discharge) stud welding utilizes the arc heat and pressure to attach the stud to the workpiece, which consists of the arc. ignition, arcing and pressure welding stages. In order to predict the dynamic behavior of the CD stud welding process, mechanical and electrical models are employed in this work. While the mechanical model estimates the duration of each stage, the electrical model predicts the voltage and current waveforms using the RLC circuit. Effects of process parameters such as the electric components and spring force are analyzed through simulation. It is found that the contact resistance and gap between the stud and base metal influence the tip fusing and arcing duration. The calculated results showed reasonably good agreements with the experiment results.

CD 스터드 용접의 해석 및 결함 분석 Part 2 : 기공 제어

오현석,유중돈,Oh Hyun-Seok,Yoo Choong-D. 대한용접접합학회 2006 대한용접·접합학회지 Vol.24 No.3

Since the voids occur at the CD stud welds, the mechanism of void formation and void reduction method are investigated in this work. It is speculated that the voids are formed because of high short-circuit current above 1000A. When the simple flow model is used to estimate the void trapping condition, the most voids are trapped at the weld mainly due to fast cooling rate of the CD stud weld. Since it is almost impossible to remove the voids completely, a method is proposed to reduce the void by decreasing the short-circuit current at the end of the arcing time. The experimental results show that the void is reduced by decreasing the short-circuit current to 1000A.

전파 망원경 수신기 전단부용 극저온 22 GHz 대역 저잡음 증폭기 모듈 설계 및 제작

오현석,이경임,양승식,염경환,제도흥,한석태,Oh Hyun-Seok,Lee Kyung-Im,Yang Seong-Sik,Yeom Kyung-Whan,Je Do-Heung,Han Seog-Tae 한국전자파학회 2006 한국전자파학회논문지 Vol.17 No.3

본 논문에서는 pHEMT(pseudo-morphic High Electron Mobility Transistor)로 구성된 저잡음 증폭기 MMIC(Monolithic Microwave Integrated Circuit)를 이용하여 극저온에서 동작하는 전파 망원경 수신기 전단부용 22 GH2 대역 저잡음 증폭기 모듈을 설계, 제작하였다. pHEMT MMIC 선정에는, 극저온에서의 동작이 입증된 pHEMT 공정을 사용하여 제작된 저잡음 증폭기 MMIC를 선택하였다. 선정된 2개의 MMIC는 박막(thin film) 세라믹 기판에 장착하여 모듈화 하였다. 모듈화 시 하우징(housing)과 캐리어(carrier) 사이의 간극을 제거하고 전파 흡수체를 사용하여 불필요한 구조에 의한 발진을 제거하였다. 또한 커넥터와 기판 사이의 부정합으로 나타나는 잡음 및 이득의 열화를 리본 조정을 통해 개선시켜 상온에서 최적의 성능을 가지도록 했다. 제작된 증폭기 모듈은 상온에서 $21.5{\sim}23.5GHz$ 대역 내 이득 $35dB{\pm}1dB$, 잡음지수 $2.37{\sim}2.57dB$를 보였다. 제작된 증폭기는 헬륨 냉각기를 이용하여 $15^{\circ}K$로 냉각 후 측정 결과, 대역 내에서 이득 35 dB 이상, 잡음온도 $28{\sim}37^{\circ}K$를 얻었다. In this paper, the cryogenically cooled low noise amplifier module for radio telescope receiver front-end using pHE-MT MMIC is designed and fabricated. In the selection of MMIC, the MMIC fabricated with the pHEMTS providing successful cryogenic operation are chosen. They are mounted in the housing using the thin film substrate. In the design of the housing, the absorber and the elimination of the gap between the carrier and the housing as well removed the unnecessary oscillations by its structure. The mismatch is improved by ribbon-tuning to provide the best performance at room temperature. The fabricated module shows the gain of $35dB{\pm}1dB$ and the noise figure of $2.37{\sim}2.57dB$ at room temperature over $21.5{\sim}23.5GHz$. In the cryogenic temperature of $15^{\circ}K$ cooled by He gas, the measured gain was above 35 dB and flatness ${\pm}2dB$ and the noise temperatures of $28{\sim}37^{\circ}K$.

엑시톤 억제층 두께에 따른 유기 광기전력 소자의 특성

오현석,이준웅,Oh, Hyun-Seok,Lee, Joon-Ung 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.12

Photovoltaic effects in organic solar cell were studied in a cell configuration of ITO/PEDOT:PSS/CuPc(20 nm)/$C_{60}$(40 nm)/BCP/Al(150 nm) at room temperature. Here, the BCP layer works as an exciton blocking layer. The exciton blocking layer must transport electrons from the acceptor layer to the metal cathode with minimal increase in the total cell series resistance and should absorb damage during cathode deposition. Therefore, a proper thickness of the exciton blocking layer is required for an optimized photovoltaic cell. Several thicknesses of BCP were made between $C_{60}$ and Al. And we obtained characteristic parameters such as short-circuit current, open-circuit voltage, and power conversion efficiency of the device under the illumination of AM 1.5.

쿼드팩을 이용한 소형 Ka 대역 송수신(T/R) 모듈의 설계 및 제작

오현석(Hyun-Seok Oh),염경환(Kyung-Whan Yeom),정민길(Min-Kil Chong),나형기(Hyung-Gi Na),이상주(Sang-Joo Lee),이기원(Ki-Won Lee),남병창(Byung Chang Nam) 한국전자파학회 2011 한국전자파학회논문지 Vol.22 No.3

본 논문에서는 Ka 대역 위상 배열 레이더용 송수신(T/R: Transmit/Receive) 모듈의 설계 및 제작을 보였다. Ka 대역 송수신 모듈 구성 시 Ka 대역의 특수성을 고려하여 5비트(bit) 위상천이기와 5 비트 30 ㏈ 디지털 가변감쇠기를 송수신 공통으로 사용하였으며, 서큘레이터는 T/R 모듈 외부에 부착되는 형태로 구성하였다. 단위 안테나당 송신 출력은 1 W 이상 잡음 지수는 8 ㏈ 미만으로 설정하였으며, 설계된 T/R 모듈의 RF부의 크기는 5 ㎜×4 ㎜×57 ㎜로 소형화를 달성하였다. 설계된 T/R 모듈을 구현하기 위하여 T/R 모듈에 소요되는 개별 ㎜IC 검증후 단위 T/R 모듈을 검증하는 방법을 사용하였다. 제작된 T/R 모듈은 설계 시 예측한 바와 같이 단위 T/R 모듈의 입력 5 ㏈m에서 출력 30 ㏈m 이상을 보였으며, 수신부는 잡음 지수 8 ㏈ 미만, 이득 20 ㏈ 이상을 얻었다. In this paper, the design and fabrication of a transmit/receive(T/R) module for Ka-band phased array radar is presented. A 5bit digital phase shifter and digital attenuator were used in co㎜on for both transmitter and receiver considering unique Ka-band characteristic. The circulator was excluded in the T/R module and was placed outside T/R module. The transmitting power per element antenna is designed to be about 1 W and the noise figure is designed to be below 8 ㏈. The designed T/R module RF part has a compact size of 5 ㎜×4 ㎜×57 ㎜. In order to implement the T/R module, ㎜ICs used in T/R module was separately assessed before assembly of the designed T/R module. The transmitter of the fabricated T/R module shows about 1 W at 5 ㏈m unit module input power and the receiver shows a gain of about 20 ㏈ and a noise figure of below 8 ㏈ as expected in the design stage.

비식별 데이터의 재식별 위험성에 관한 연구

오현석(Oh Hyun Seok),용우석(Yong Woo Seok),강동현(Kang Dong Hyun),이원석(Lee Won Seok) 한국IT서비스학회 2018 한국IT서비스학회 학술대회 논문집 Vol.2018 No.-

최근 기업이나 정부 등 다양한 출처로부터 개인정보 데이터의 수집 및 분석이 늘어나는 추세이다. 특히 빅데이터 기반의 마이닝 또는 머신러닝 모델을 통한 활용 범위가 확장 됨에 따라 개인정보 데이터 유통에 대한 관심이 높아지고 있다. 이러한 배경에서 개인정보 유출을 막는 것은 매우 어려운 문제이지만, 개인정보보호 측면에서 필수적으로 해결이 필요하다. 이에 따라 데이터 유통 시 원본데이터의 특정 속성들을 삭제, 범주화/일반화 등의 방법으로 비식별화한 뒤  -익명성과 같은 프라이버시 모델을 적용하여 재식별 가능성을 최소화하는 것이 바람직하다. 하지만 기존 프라이버시 모델들을 준식별자에 의존한 연결 공격 외에 민감 속성에 의한 연결 공격에 대한 한계가 존재한다. 본 논문에서는 이러한  -익명성 모델이 가지는 취약점에 대해 보다 안전한 재식별 가능성 분석 모델을 제안하고, 그 효용성을 실제 개인정보 데이터에 기반한 실험을 통해 검증하였다.

리테일테인먼트에 따라 구매특성과 구매효용이 구매의도에 미치는 영향

오현석(Hyun Seok Oh),전홍식(Hong sik J. Cheon) 한국유통과학회 2019 한국유통과학회 학술대회 논문집 Vol.2019 No.-

Purpose - The development of technologies lead the volume of sale on online market increase but an off-line shopping center is still a core component in the omni-channel strategy. It is generally thought that high-level retailtainment on brick and mortar store affects purchase intentions positively, but some previous studies dispute that and have reported that retailtainment does not affect purchase intentions. So we have studied the additional factors effect - the nature of purchase and utility - with retailtainment. Research design, data, and methodology - There are 8 treatment groups which were assigned by the method of retailtainment (high vs. low), nature of purchase (essential vs. non-essential), and utility (acquisition vs. transaction). A total of 240 subjects (office workers = 163, 68%; undergraduates = 77, 32%; average age = 30s; female =39%) were divided into groups and exposed to one of the eight scenarios. Participant’s purchase intention was the dependent, and ANOVA and L-matrix were used to analyze for main and interactive effects between factors. Results - First, the main effect and interactive effect between retailtainment and the nature of purchase are significant. We also found that the contrast between essential and non-essential at low-level retailtainment is higher than that of high-level retailtainment. Second, in the case of retailtainment and utility, transaction utility under high-level retailtainment affects purchase intentions positively. Third, between the nature of the purchase and utility, the main effect of the nature of purchase and the interactive effect is significant, but the main effect of utility is not significant. In the case of non-essential goods, the purchase intention was high when transaction utility was provided but in the case of essential goods, acquisition utility increased purchase intentions. Finally, when transaction utility is given, purchase intentions of essential goods increase under low retailtainment, and