망막전위도검사에서 ERG-Jet 단극전극과 Burian-Allen 양극전극의 파형 비교

박지현,이호경,박성준,김윤화,Jihyun Park,MD,Hokyung Lee,MD,Sung Joon Park,MD,Yoon Hwa Kim 대한안과학회 2010 대한안과학회지 Vol.51 No.9

Purpose: To compare electroretinogram (ERG) waveforms acquired using an ERG-jet electrode and a Burian-Allen electrode. Methods: ERGs were recorded with an ERG-jet electrode and a Burian-Allen electrode from both eyes of 29 volunteers. Three consecutive recordings were obtained with both electrodes from the left eye of another 6 volunteers. Peak-to-trough amplitudes and peak implicit times were compared between both eyes, and between the 2 types of electrodes. Interpersonal and intrapersonal variation were also compared. Results: The differences in amplitude and implicit time between the right and left eyes were not influenced by the type of electrode. The amplitude of the ERG acquired using the Burian-Allen electrode, however, showed significant differences between both eyes, contrary to the amplitude acquired using the ERG-jet electrode. ERG recordings obtained using the ERG-jet electrode generally showed higher amplitude, shorter implicit time, and less interpersonal and intrapersonal variation than ERG recordings obtained using the Burian-Allen electrode. Conclusions: In this application, the ERG-jet ERG electrode appeared to be superior to the Burian-Allen electrode in terms of both usefulness and consistency. J Korean Ophthalmol Soc 2010;51(9):1217-1223

키워드 통계 분석을 활용한 중국의 교육 연구 동향 분석 ― 13차 5개년(2016~2020) 규획 기간을 중심으로

박지현 ( Park¸ Jihyun ),김민정 ( Kim¸ Minjeong ),노규형 ( Rho¸ Kyoohyoung ) 한국중국학회 2021 중국학보 Vol.97 No.-

본 연구는 13차 5개년(2016~2020) 규획 기간에 중국 학술저널에 발표된 교육 관련 논문을 中國知網(cnki.net)에서 ‘교육이론과 교육관리’ 주제를 중심으로 전수 추출해 그 키워드의 연도별 분포 상황과 변화 추이 등을 분석하고 교육 정책과 수용 간의 관계 양상을 논한 것이다. 데이터 분석의 대상이 된 전체 논문 수는 17,833개이고, 그 논문들에 1번 이상 출현한 키워드는 총 22,646개로 각 키워드의 출현빈도 수를 산출해서 데이터 분석을 수행하였다. Python 3.8.5 환경에서 작업했으며 자료의 시각화에는 微詞雲(https://www.weiciyun.com/) 생성기와 Matplotlib 3.3.2를 이용하였다. This study extracted all China’s education-related papers published in Chinese academic journals during the 13th Five-Year Plan period (2016-2020) from cnki.net (China National Knowledge Infrastructure, 中國知網), focusing on the subjects of Education Theory and Education Management. We then analyzed the year-by-year distribution of the keywords and their change trends, examining the relationship between China’s education policy and its acceptance. The total number of papers subject to data analysis was 17,833, with 22,646 keywords appearing in those papers more than once. Data analysis was performed by calculating the frequency of appearance of each keyword. The Python 3.8.5 version was used, and the Mini Tag Cloud (微詞雲, https://www.weiciyun.com) generator and Matplotlib 3.3.2 were employed for the data visualization.

수중 주파수 선택적 채널에서 블록 인터리빙 기법을 적용한 길쌈부호화 기법의 성능

박지현,윤종락,Park, Jihyun,Yoon, Jong Rak 한국음향학회 2019 韓國音響學會誌 Vol.38 No.2

본 논문은 수중 주파수 선택적 채널에서 블록 인터리빙 기법을 적용한 길쌈부호기법의 통신성능을 평가하였다. 블록 인터리빙은 디지털 데이터 열을 확산 분산하고 재배치하는 기법으로 주파수 선택적 채널에서 연집오류(burst error)의 집중을 분산시켜 성능을 향상하게 시키는 기법으로 블록 인터리빙 기법이 적용되고 있다. 수조 실험에서 블록 인터리빙이 적용된 길쌈부호의 성능을 평가한 결과 주파수 비 선택적 채널에서 블록 인터리빙을 적용한 길쌈부호의 성능의 차이가 없었다. 하지만 주파수 선택적 채널에서는 블록 인터리빙이 적용된 길쌈부호가 길쌈부호보다 2 dB 이득이 발생하였으며, 이로 인해 수중 음향 통신 성능향상에 기여함을 확인하였다. In this paper, we evaluate the communication performance of convolutional code with block interleaving in a frequency-selective channel. Block interleaving is a technique for spreading and rearranging digital data streams. A block interleaving technique is applied to improve the performance by dispersing the concentration of burst errors in a frequency-selective channel. As a result of evaluating the performance of the convolutional code with block interleaving in the water tank experiment, There was no difference in the performance of convolutional codes using block interleaving in a frequency-selective channel. However, in the frequency-selective channel, the convolutional code with block interleaving has a gain of 2dB, and it is confirmed that the underwater acoustic communication performance is improved.

공압 gripper를 적용한 해양 건설 ROV 시스템 개발

박지현,황요섭,Park, Jihyun,Hwang, Yoseop 한국정보통신학회 2022 한국정보통신학회논문지 Vol.26 No.11

The safety of marine construction workers and marine pollution problems are occurring due to large-scale offshore construction. In particular, underwater construction work in the sea has a higher risk than other work, so it is necessary to apply an unmanned alternative system that considers the safety of the workers. In this paper, the ROV system for offshore construction has been developed for underwater unmanned work. A monitoring system was developed for position control through the control of underwater propellants, pneumatic gripper, and monitoring of underwater work. As a result of the performance evaluation, the underwater movement speed of the ROV was evaluated to be 0.89 m/s, and it was confirmed that the maximum load of the pneumatic gripper was 80 kg. In addition, the network bandwidth required for underwater ROV control and underwater video streaming was evaluated to be more than 300Mbps, wired communication at 92.7 ~ 95.0Mbit/s at 205m, and wireless communication at 78.3 ~ 84.8Mbit/s.

시·공간 변동 수중음향 채널에서 CAZAC 코드를 적용한 반송파 주파수 옵셋 보상 기법의 성능평가

박지현,배민자,김종주,윤종락,Park, Jihyun,Bae, Minja,Kim, Jongju,Yoon, Jong Rak 한국정보통신학회 2016 한국정보통신학회논문지 Vol.20 No.7

수중 음향 다중경로 채널에서 수중음향 통신 시스템의 성능은 채널의 시변적 경계면 상태 변동에 의해 영향을 받는다. 이러한 채널에서 시공간적 변동에 의해 송신 신호와 수신 신호의 위상과 주파수가 일치하지 않아 반송 주파수 옵셋이 발생되고 위상편이키잉 방식의 수중음향통신시스템의 성능을 저하시킨다. 본 논문에서는 수중 음향 통신 채널의 시 공간적 변동 채널에서 위상 코드를 적용한 반송 주파수 옵셋 보상 추정 기법의 성능을 평가하였다. 위상 코드는 주파수 옵셋을 추정하고 보상하기 위한 코드로 CAZAC를 적용하였으며, 실내 수조에서 성능을 평가하였다. QPSK 시스템에 위상코드를 적용한 결과는 적용하지 않은 경우보다 약 4-6배 비트오류율이 개선되었다. In underwater acoustic multipath channel, a performance of underwater acoustic (UWA) communication systems is affected by dynamic variation of boundary and high temporal and spatial variability of the channel conditions. Time and spatial variations of UWA channel induce a carrier frequency offset (CFO) since a phase and a frequency of received signal mismatch with a transmitting signal. Therefore, a performance of a phase shift keying underwater acoustic communication system is degraded. In this study, we have analyzed a performance of CFO estimation and compensation using a phase code in time and spatial variation channel. A constant amplitude zero autocorrelation (CAZAC) signal is applied as a phase code signal and its performance is evaluated in water tank. The bit error rate of a quadrature phase shift keying (QPSK) system with a phase code is improved about 4 to 10 times better than that without a phase code.

국방 무기체계 소프트웨어 신뢰성 향상을 위한 소프트웨어 동적 결함 분석

박지현,최병주,Park, Jihyun,Choi, Byoungju 한국정보처리학회 2018 정보처리학회논문지. 소프트웨어 및 데이터 공학 Vol.7 No.7

국방 무기체계에서의 소프트웨어 비중이 증가하고 있으며 구조도 점차 복잡해지고 있어, 이에 따른 신뢰성 검증이 매우 중요하다. 특히 무기체계 시스템을 구성하는 소프트웨어 구성 요소 들의 상호 작용에 따라 발생하는 결함은 정적 시험 및 코드 실행률 점검 수준의 동적 시험만으로는 예방하기가 어렵다. 본 논문에서는 소프트웨어의 동적 결함 유형을 분류 개발한다. 미 국방부 무기체계에 사용하는 오픈 소스 소프트웨어(OSS)에서 보고된 이슈 분석을 통하여 본 논문에서 분류한 동적 결함이 실제로 발생하며, 이들은 대체로 통합 이후 발생하는 결함이며, 재현이 어렵고, 결함 원인 파악이 어려웠음을 보인다. 이 분석 결과를 기반으로 무기체계 신뢰성 검증을 위하여 소프트웨어 통합 시험 개선의 중요성을 도출한다. The importance of software in military weapon systems is increasing, and the software structure is becoming more complicated. We therefore must thoroughly verify its reliability. In particular, the defects from the interaction of the software components that make up the weapon system are difficult to prevent only with static testing and code coverage level dynamic testing. In this paper, we classify dynamic software defect types and analyze the issues reported in the Open Source Software (OSS) used in the US department of defense weapon systems. The dynamic defects classified in this paper usually occur after integration, and it is difficult to reproduce and identify the cause. Based on this analysis, we come to the point that the software integration test must be enhanced in order to verify the reliability of the weapon system.

선천성 코눈물관폐쇄에서 코눈물관내 실리콘관삽입술의 수술성공률에 영향을 미치는 요인

박지현,이용주,김성주,장재우,Jihyun Park,Yong Ju Lee,Sung Joo Kim,Jae Woo Jang 대한안과학회 2011 대한안과학회지 Vol.52 No.3

Purpose: To determine the factors affecting the outcome of silicone intubation for congenital nasolacrimal duct obstruction. Methods: A total of 233 eyes of 200 children that received silicone intubation were enrolled in a retrospective study. Results: The overall success of silicone intubation was 193 of 233 eyes (82.8%). There was no significant difference in success rate between age groups. Tube retention time did not affect the success rates. Immediate tube dislocation as early as within 2 weeks did not lower the success rates (81.5%). Success rates were significantly lowered by persistent epiphora at the point of tube removal (p < 0.001). Conclusions: The outcome of silicone intubation is determined by symptomatic improvement, which is not affected by tube retention time. Unplanned early tube dislocation may not affect the outcome of silicone intubation unless symptoms are persistent, and sufficient tube retention time does not ensure the success if symptoms are persistent. J Korean Ophthalmol Soc 2011;52(3):266-271

면역기능이 정상인 재발성 전안부 포도막염환자에서 거대세포바이러스의 임상적 중요성

박지현,정재림,이성호,홍영재,Jihyun Park,Jae Lim Chung,Sung Ho Lee,Young Jae Hong 대한안과학회 2010 대한안과학회지 Vol.51 No.9

Purpose: This study aimed to identify various infectious causes in unilateral recurrent hypertensive anterior uveitis in immunocompetent individuals. Methods: Twenty eyes of 20 patients diagnosed with recurrent hypertensive anterior uveitis, who had negative systemic uveitis lab results, were enrolled. Polymerase chain reaction (PCR) was performed in the aqueous humor and peripheral blood specimens to detect the following infectious agents: cytomegalovirus (CMV), herpes simplex virus-1 (HSV-1), varicella zoster virus (VZV), toxoplasma. Results: The mean age of 20 patients was 41.8 ± 15.9 year (19-77 year), and 14 (70%) patients were male. CMV was positive in 7 eyes (35%) and was detected only in aqueous humor. HSV-1 was positive in 5 (25%) eyes; only in aqueous humor in 2 eyes, only in blood in 1 eye, and in both specimens in 2 eyes. Only 1 (5%) eye was positive for toxoplasma in the aqueous humor. Conclusions: This study demonstrated that CMV might be another major infectious cause in recurrent hypertensive anterior uveitis in immunocompetent patients. If CMV is detected, it might be reasonable to add appropriate antiviral agents, rather than treating only with immunosuppresive and hypotensive drugs. J Korean Ophthalmol Soc 2010;51(9):1245-1249

동양적 문화가치를 기반으로 한 미래 모바일 디자인의 개념모델 연구

박지현(PARK Jihyun),이순종(LEE Soonjong),정성모(CHUNG Sungmo),윤수현(Yoon Suhyun),채승진(CHAE Sungzin) 한국디자인학회 2006 한국디자인학회 학술발표대회 논문집 Vol.- No.-

원통형 처리 용기를 이용한 후추의 광펄스 살균 효과

박지현 ( Jihyun Park ),이광민 ( Gwangmin Lee ),김진원 ( Jin Won Kim ),이경미 ( Gyeong Mi Lee ),신정규 ( Jung-kue Shin ) 한국산업식품공학회 2018 산업 식품공학 Vol.22 No.3

비가열 살균 기술 중 하나인 광펄스 기술을 이용하여 후추에 존재하는 미생물의 사멸 효과를 원통형 처리 용기를 이용하여 검토하였다. 후추에 존재하는 미생물의 오염도는 일반세균은 약 2.0-4.0×10⁶ CFU/g, Bacillus cereus는 약 3.0-5.0×10³ CFU/g이었다. 펄스 수 5 pps, 광원과 처리용기 사이의 거리 4 cm의 동일한 조건에서 빛의 세기를 달리하여 처리하였을 경우 빛의 세기가 강할수록 사멸정도는 증가하였으며, 빛의 세기 1,000 V에서 흑후추의 경우 일반세균은 0.55 log, B. cereus는 0.6 log, 백후추의 경우 일반세균은 0.7 log, B. cereus는 0.6 log의 사멸효과를 보였다. 펄스 수를 달리하였을 경우에는 펄스수가 증가할수록 높은 사멸율을 보였으며, 광원과 처리 용기사이의 거리에 따른 사멸효과를 거리가 짧을수록 사멸율은 증가하였다. 입자의 크기에 따른 사멸 효과는 입자의 크기가 클수록 살균효과가 높은 것으로 나타났다. 후춧가루의 살균에 있어 광펄스 기술은 처리 조건에 따라 40-80%정도의 사멸율을 나타내어 후춧가루의 비가열 살균 기술로서의 적용 가능성을 볼 수 있었다. In this study, the effect of intense pulsed light (IPL) treatment in a tube-shaped treatment chamber on microbial inactivation in powdered pepper was investigated. Untreated samples showed a degree of contamination of 2.0-4.0×10⁶ CFU/g total aerobic bacteria, and 3.0-5.0×10⁵ CFU/g Bacillus cereus. The microorganisms found in powdered pepper decreased with exposure to increasing light intensity, pulse number and treatment time. At 1,000 V, the total aerobic bacteria in powdered black pepper was reduced by 0.55 log, and in and powdered white pepper by 0.6 log cycle, and B. cereus was reduced 0.7 log in black pepper and 0.6 log cycle in white pepper. The microbial inactivation rate increased with the increase in the distance between the light source and the treatment chamber during IPL treatment. The sterilization rate of powdered pepper using IPL was 40-80%, indicating that the IPL sterilization method may find potential applications for powder foods.