Wide Angle BPM 을 이용한 광도파로열 격자 파장 필터의 해석

박준오,정영철,Park, Jun-O,Jeong, Yeong-Cheol 대한전자공학회 2002 電子工學會論文誌-SD (Semiconductor and devices) Vol.39 No.2

광도파로열 격자(AWG :Arrayed Waveguide Grating) 파장 필터는 전광 네트웍(All Optical Network)을 실현하는 매우 중요한 핵심 소자 중에 하나이다. 광도파로열 격자 파장 필터와 같은 광도파 소자를 해석 및 설계시 수학적인 해석이 필요하며, 가장 대표적인 방법은 BPM(Beam Propagation Method)이다. 본 논문에서는 Paraxial BPM과 Wide Angle BPM을 InP/InGaAsP/InP 광도파로열 격자 파장 필터 해석에 적용시켜 정화도의 차이를 고찰해 보았다. WA-BPM을 구현하기 위하여 저차의 Pade Approximant를 적용하였다. 광도파로열 격자 파장 필터의 SLL(Side Lobe Level)과 삽입손실(Insertion Loss)을 비교하여 분석하였다. 광도파로열 격자 파장 필터를 정확하게 해석 및 설계하기 위해서는 고차의 WA-BPM을 사용해야 함을 확인하였다. The key component to accomplish the WDM all optical network is an Arrayed Waveguide Grating(AWG) wavelength filter Numerical analysis is necessary for design and analysis of optical components like AWG wavelength filter. Beam Propagation Method(BPM) is the most widely-used method. In this paper, we analyze the difference between the paraxial BPM and the WA-BPM when they are applied to the analysis of InP/InGaAsP/InP AWG wavelength filter. The paraxial BPM is based on paraxial approximation, and the WA-BPM is based on the low order Pade approximant. The side lobe level(SLL) and insertion loss calculated from both methods are compared. The high order Pade approximant will to used to more accurate design and analysis of AWG.

뇌간에 발생한 단발성 뇌낭미충증 - 증례보고 -

박준오,정용구,임동준,조태형,이훈갑,이기찬,서중근,Park, Juno,Chung, Young-Gu,Lim, Dong-Jun,Cho, Tae-Hyong,Lee, Hoon-Kap,Lee, Ki-Chan,Suh, Jung-Keun 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.10

Isolated brainstem invlovement of neurocysticercosis is rare. We present the clinical and radiological features of a patient with a solitary cysticercus granuloma in the brainstem confirmed by MRI and CSF ELISA test. Good response was obtained from conservative treatment, using praziquantel. We believe that patients from regions where cysticercosis is endemic, who have no systemic disease, who present with nonprogressive symptoms and signs of brainstem involvement, and display a solitary ring-enhancing mass in the brainstem measuring less than 20mm on neuroimaging may be managed conservatively.

열차하중에 따른 교량 신축부 장대레일 축력 연구

박준오(Park Jun O),김종민(Kim Jong Min),김우진(Kim Woo Jin) 한국철도학회 2006 한국철도학회 학술발표대회논문집 Vol.- No.-

It is widely known that the temperature variation introduces the axial force along a CWR (Continuous Welded Rail) in the railway bridges. Additional axial forces are generated due to many other reasons. These includes the interaction between the bridge girder and the CWR; acceleration or deceleration of the vehicles; support rotation (or deflection) of the girder. Among aforementioned reasons, this study investigates the influence of the support rotation on additional axial forces throughout the numerical study and the field test. Several strains gauges are installed along the CWR and the strains are measured under passing trains. It is expected that the elaborated estimation of the axial force on CWR will be beneficial for future railway maintenance.

경부고속철도 토공부의 자갈도상에 대한 진동특성 연구

박준오(Park Jun-O),강태구(Kang Tae-Ku),홍원표(Hong Won-Pyo) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.5월

The gravel ballast in the ballasted track has the function to not only transfer/scatter the train loads to subgrade through rail and sleeper but also elastically support the train loads. Because track irregularities results inevitably from the repetitive train loads, the track maintenance should be undertaken for correcting them. By analyzing the track maintenance history in the Gyeongbu high speed railway, this study tries to choose the local two spots in the railway in which the repair frequencies are maximum and relative small; to analyze their dynamic characteristics as well as grade; and to compare them with maintenance history. As the dynamic characteristics of track, the vertical displacement and vibrating acceleration of sleeper as well as acceleration of ballast are measured/analyzed. Furthermore, by collecting soil and gravel on the reinforced roadbed and undertaking ballast screening test, the size distributions are compared with grade distribution standards of high speed railway.

RF 소자의 표면탄성파 공진에 대한 광학적 측정

박준오(Park, Jun-Oh),장원권(Jang, Won-Kweon) 한국산학기술학회 2010 한국산학기술학회논문지 Vol.11 No.9

표면탄성파를 이용한 RF소자의 성능을 단순히 작동 유무로만 평가할 수 있는 전기적인 성능 평가방법과 달 리 위치에 따른 표면탄성파의 형성 정도를 실시간으로 검사할 수 있는 광학적 방법을 제시하였다. 광학적 방법을 이 용한 표면 탄성파의 측정 조건과 한계를 제시하였고 간섭 및 회절 현상을 이용하여 RF신호의 입력 유무에 따른 광학 적 해석을 하였다. 단일 모드 레이저를 이용하여 중심 주파수가 105MHz인 중계기 필터의 동작을 실험적으로 측정하 고 이론적으로 분석하였다. 본 논문에서는 다기능 서비스를 제공하는 복합 주파수 RF 모듈의 고품질화를 위한 방법 으로 표면탄성파의 에너지 분포를 시각화하고 실시간으로 평가할 수 있는 광학적 방법을 제시하였다. Unlike the electric method capable of checking only product defect, the real time optical metrology is suggested for measuring and visualizing vibration with respect to position of surface acoustic wave in RF device. The measuring limits and conditions for surface acoustic wave is given, and the interference and diffraction due to RF signal are analyzed by optical interpretation. A single mode laser and a 105MHz-center-frequency repeater filter were employed for experiments and theoretical analysis. In this paper, the optical metrology providing visual energy distribution and real time inspection for surface acoustic wave is proposed for development of high quality multi-service and multi-frequency RF module.

3차원 모델링 데이터 가시화 효율성 향상방안에 관한 연구

박준오(Park Jun oh),안응식(Ahn Eung Sik),이윤(Lee Yun) 대한공간정보학회 2010 한국지형공간정보학회 학술대회 Vol.2010 No.3

최근 3차원 기술의 발전으로 도시를 구성하는 시설물을 3차원으로 가시화하고 관리하는 기술이 주목받고 있다. 3차원 도시 시설물 관리를 위해서는 3차원 시설물(건물) 데이터의 효율적 가시화 기술이 필수적이다. 본 연구에서는 3차원 데이터 가시화 기술을 GIS 시스템에 적용하여 성능을 확인하였다. 정점(Vertex)·텍스처(Texture)버퍼(Buffer), 텍스처 LOD(Level of Detail) 설정 기술을 활용하여 시스템의 성능을 시험한 결과 가시화 속도가 약 15배 정도 향상되었다. 본 연구에서 제시한 기술은 대용량 고품질 3차원 모델링 데이터의 서비스를 위한 기반 기술로 활용할 수 있다는데 의의가 있다.

온도에 의한 고속선 교량의 신축변위 거동 분석

박준오(Park Jun-O),진남희(Jin Nam-Hee),우용근(Woo Yong-Keun) 한국철도학회 2009 한국철도학회 학술발표대회논문집 Vol.2009 No.11월

The amount of longitudinal displacement of a ballasted track bridge is affected by temperature as well as span length of bridge, axial force of continuous welded rail, fastening force of rail fastening device and type of shoe, etc. This longitudinal displacement of a bridge changes the density of ballast at the end of a bridge, and finally causes the track irregularities like longitudinal level of rail. This study analyzes the effect of temperature on the longitudinal displacement of Gyeongbu high speed railway bridges. Among the health monitoring system in Gyeongbu high speed line, longitudinal displacement meters and thermometers have been installed in 2 prestressed box girder bridges which have different span lengths. By comparing the longitudinal displacements of these bridges with daily and long termly ambient air temperature changes from the long term measured data, the effects of temperature change on bridge expansion are analyzed and the times when maximum expansion or contraction happens are identified.

철도교 상시계측시스템용 검교정기 제작 및 시험

박준오(Park Joon-Oh),이준석(Lee Jun S.),최일윤(Choi Il-Yoon) 한국철도학회 2002 한국철도학회 학술발표대회논문집 Vol.- No.-

Calibration of the health monitoring system is considered in this study. For this, brief introduction on the realtime monitoring system, installed in some of the Korea Highspeed Railway bridges, is made and specifications of the calibrators are outlined. Calibration method is next explained for each sensor and detailed procedures are illustrated. Calibration results will be published elsewhere and modification of the gauge factors will also be investigated in detail.

철도교 상시계측시스템의 교정 및 교정상수 설정에 관한 연구

박준오(Joon-Oh Park),이준석(Jun S. Lee),최일윤(ll-Yoon Choi),민경주(Kyung-Ju Min) 한국철도학회 2002 철도저널 Vol.5 No.3

A health monitoring system becomes a useful tool to obtain information on long term behavior of the important railway structures such as very long span and special type bridges. The health monitoring system not only gives the direct measurement data of the railway bridges but also provides the basic data on the maintenance of the structures. Therefore, periodic calibrations of the health monitoring system will be a necessary step toward precise and accurate assessment of the railway bridges. In this study, the calibration and gauge factor readjustment process made for the health monitoring system installed in the railroad bridges is reviewed and some findings are explained in detail: specifically, the calibrators made for this purpose are illustrated and the regression processes of the calibration on long-term displacement using water level sensor, longitudinal displacement using LVDT sensor, instantaneous displacement using LVDT sensors and accelerometer are described in full length. Based on the regression results, it was found that the gauge factors need to be readjusted according to the regression equation but, since the deviation or shift is not serious so far, long-term observation on each sensor is also recommended. Future work will be concentrated on the long-term analysis of each sensor and on the database creation so that the assessment of the structures is possible

대절토부 사면의 패널식 옹벽보강에 따른 안정성 검토

최동욱,박준오,김대현,Dong-wook Choi,Jun-o Park,Daehyeon Kim 한국지반신소재학회 2024 한국지반신소재학회 논문집 Vol.23 No.2

대절토사면 안정성 확보를 위한 보강공법에 대한 다양한 신기술, 신공법이 적용되고 있지만 현장 지반정수 고려에 대한 설계적 한계가 존재하여 실제 시공 시 설계와 현장 지반 조건이 상이한 결과가 발생하고 있다. 본 연구대상지역인 여수시 일원에 있는 옹벽의 경우 5단계 옹벽 시공예정중이나, 현재 2단계 시공완료 시점에서 옹벽 상부의 균열, 옹벽전면의 침하 및 우수 유출등이 확인되었다. 1, 2단계 옹벽 시공 완료후, 발생된 옹벽 상부의 균열 및 침하와 옹벽 전면의 우수 유출에 대한 문제점을 발견하고 기존 안정성 검토의 결과를 재검토하고자 하였다. 기존 설계단계에서 붕적층에 대한 명확한 검토가 이루어지지 않아 지하수 유출로 인한 문제임을 확인하였으며, 이에 지하수위 조건을 보수적으로 반영하고자 옹벽 최상부에 지하수위선을 위치시켜 사면에 대한 안정성검토를 수행하였다. 검토결과, 우기시 안전율은 1.31로 기준안전율 1.3을 상회하는 결과를 확인하였으나, 지진시 안전율이 1.12로 기준안전율 1.3을 만족하지 못하는 것으로 확인되었다. 이에 기존 1, 2단 시공된 옹벽은 그라우팅을 이용한 마이크로 파일과 같은 보강공법을 적용하고, 붕적층에 대한 명확한 검토 수행수 추가 공사가 이루어져야할 것으로 사료된다. Various innovative technologies and methods are being applied to ensure the stability of steep rock slopes. However, there are design limitations concerning site ground conditions, leading to discrepancies between the designed and actual ground conditions during construction. In the case of the retaining wall in Yeosu, where the study area is located, although the construction of a 5-stage retaining wall is planned, at the current completion of the second stage, cracks on the upper part of the wall, settlement in the front of the wall, and seepage have been observed. After the completion of stages one and two, issues regarding cracks and settlement on the upper part of the wall and seepage in the front of the wall were discovered. Thus, there was a need to reevaluate the results of the existing stability assessment. It was confirmed that the issue was due to groundwater leakage, attributed to the lack of clear assessment of the colluvial soil layer during the initial design stage. Therefore, to conservatively reflect groundwater level conditions, a groundwater level contour was positioned at the top of the wall to conduct a slope stability assessment. The assessment results indicated that the safety factor during the rainy season exceeded the required value of 1.3, with a calculated safety factor of 1.31. However, during seismic events, the safety factor was determined to be 1.12, falling short of the required safety factor of 1.3. Therefore, it is suggested that the existing retaining walls constructed during stages one and two undergo reinforcement using methods such as micro-piles with grouting, and additional work should be carried out to ensure a clear assessment of the colluvial soil layer.