• 한국위성정보통신학회논문지
• /
• 제12권3호
• /
• pp.108-113
• /
• 2017

일반적으로 Operator on Board로 불리는 OBCP (On-Board Control Procedure)는 기존 탑재소프트웨어를 변경하지 않으면서 동적으로 지상 또는 온보드에서 명령과 로직이 포함된 특정 프로시저를 로딩, 언로딩 및 실행 할 수 있으며, OBCP를 통해 기존 위성의 제한된 자율성 및 강인성을 증대 시킬 수 있다. 탑재소프트웨어의 OBCP의 핵심은 OBCP 엔진이며, OBCP 엔진은 스크립트 기반의 프로시저를 해석 및 실행 할 수 있는 인터프리터 형태로 구현되어 있으며 내부적으로 가상머신을 가지고 있다. 탑재소프트웨어팀에서는 2010년부터 내부적으로 OBCP에 대해서 계속 연구를 수행하였으며 ERC32 프로세서 기반의 Java KVM, RTCS/C 및 KKOMA와 같은 자체 OBCP 엔진을 개발하였다. 최근에는 ESA OBCP 표준에 대한 연구를 계속 진행하고 있으며 LEON2-FT/AT697F 프로세서 기반에서 Lua와 MicroPython을 이용한 OBCP 엔진 연구를 진행하고 있다. 본 논문에서는 현재 가장 활발히 사용되고 있는 오픈소스 기반의 Lua를 탑재소프트웨어의 OBCP 엔진으로 사용하기 위하여 VxWorks 기반의 AT697F 프로세서에서의 설계 및 구현 방법에 대해서 기술하며, 시뮬레이터와 실제 하드웨어의 테스트 결과와 함께 성능 비교 분석을 수행한다.

• Journal of Radiation Protection and Research
• /
• 제25권4호
• /
• pp.191-195
• /
• 2000

현재 서울대학교병원에서 진행중인 연구의 일환으로 혈관 내 방사선치료 시 시술자의 방사선피폭 정도 및 위험성에 대해 알아보고자 연구를 시행하였다. 심장혈관 폐색으로 연구에 포함되어 방사선치료른 시행 받은 42명의 환자 중 측정이 완벽한 34명의 자료를 토대로 분석을 시행하였다. 혈관내 방사선치료는 관상동맥성형술 직후 풍선도자법을 이용하여 대상 동맥의 중막에 17 Gy를 조사하였다. 사용된 동위원소는 $^{188}Re$이었으며 GM측정기로 각기 다른 8점에서 피폭선량을 측정하였다. 환자의 심장부위에서 10cm, 40cm 떨어진 지점을 시술자의 최대피폭량, 전신피폭량의 기준으로 삼았다. 치료선량의 중앙값은 111.6 mCi이었고 중앙치료시간은 576초였다. 환자 심장부위에서 l0cm, 40cm 지점의 평균 피폭 선량율은 0.43 mSv/hr, 0.30 mSv/hr 이었고, 각 지점에서의 시술 당 평균 피폭 선량은 0.07 mSv, 0.05 mSv 이었다. 이 수치는 ICRP-60나 과학기술부 고시에서 권고하고 있는 한계 피폭선량보다 훨씬 적은 값으로 현재 저울대학교병원에서 시행하고 있는 혈관내 방사선 치료법은 방사선방어 면에서 매우 안전한 방법임을 확인할 수 있었다.

• Journal of Korean Neurosurgical Society
• /
• 제40권1호
• /
• pp.16-21
• /
• 2006

Objective : Young neurosurgeons need to focus on the mortality and morbidity of aneurysmal neck clipping to develop a personal experience with an initial series. Methods : Total 88 aneurysms from 75 patients who underwent neck clipping by the same operator from 2001 to 2004 were reviewed. Patients were divided into three groups : first year [Group I], second year [Group II], and third year [Group III] in each group. Location of aneurysm, age, Fisher grade, Hunter-Hess grade [H-H grade], postoperative Glasgow outcome scale [GOS], and complications related to surgical procedures were evaluated with Chi-square and logistic regression analyses. Results : Fourteen patients had complications related to surgery [18.7%]. The major causes of mortality and morbidity related to surgery were cerebral infarction, hemorrhage and brain swelling due to intraoperative rupture, brain retraction and vasospasm. Among the 4 cases of mortality were 2 patients in Group I, 1 patient in Group II and 1 patient in Group III, and location of aneurysms were 2 internal carotid artery[ICA] and 2 posterior communicating artery[PCoA] aneurysms. There were 4 morbidity and new neurological deficits in Group I, 4 in Group II and 2 in Group III. Although mortality and morbidity during the learning curve had a statistical significance in H-H grade, age [>60 years old], and aneurysm location [especially ICA aneurysm] as variables, mortality mainly occurred in ICA and PCoA aneurysms. Conclusion : Experienced supervision or endovascular approach should be considered for the treatment of ICA and PCoA aneurysms during the learning curve.

• 한국환경과학회지
• /
• 제25권3호
• /
• pp.439-446
• /
• 2016

Domestic sewerage treatment plant is operated by activated sludge method and its modified method by using microorganism. In most cases, a method of using microorganism is directly controlled by the operator based on individual judgment through factors of DO, pH and ORP. In addition, under aerobic condition in bioreactor, energy consumption including excessive air injection is learned to be somewhat plenty. In order to solve this problem, in most of the process, improvement of internal recycling and activated environmental factor of microorganism were researched extensively. However, as factors are changed depending on various conditions, it is not sufficient as an indicator of judgment. As such, a research on operation of bioreactor that measures metabolic change in short time by directly measuring activated condition of microorganism using NADH fluorometer is required in reality.It is considered that the method like this could supplement problem of energy consumption being occurred in the existing treatment method and operational optimization of bioreactor would be enabled by controlling optimal air volume. Therefore, in this study, in order to obtain optimal operational indicator of bioreactor, proper air volume control test was performed and through batch test and site evaluation, possibility of NADH sensor being utilized as operational control indicator of bioreactor is intended to be analyzed. In order to compare with measured value, DO, ORP that are operational control indicator of existing bioreactor were used. As MLSS concentration was increased through batch test, NADH value was increased and site evaluation also showed similar tendency to batch test. Resultantly, it could be confirmed that changing level of NADH fluorometer was a sensor that could measure bioreactor condition effectively and optimized scale of bioreactor is considered to be utilized.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
• /
• pp.348-350
• /
• 1997

Because of internal voids ininsulators give rise to partial discharge(PD), which cause local breakdown and even entire insulation breakdown. Treeing due to PD is one of the main causes of breakdown of the insulating materials and reduction of the insulation life. Therefore the necessity for establishing a method to diagnose the aging of insulation materials and to predict the breakdown of insulation has become important. From this viewpoint, our studies diagnose insulation degradation using the method of computer sensing system, which has the advantages of PD and acoustic emission(AE) sensing system. To use advantages of these two methods can be used effectively to search for treeing location and PD in some materials. In analysis method of degradation. We analyzed the PD pulse and AE pulses by regression analysis, compared to these obtained the correlation coefficient and determination coefficient by T-distribution and saw that PD and AE pulses show a similar pattern on the whole. Finally using statically operator such as the center of gravity(G), the gradient of the discharge distribution(C), we have analyzed for the prediction of life which we can be obtained the time, occurred of many pulse of small discharge amplitude.

• 한국정보통신학회논문지
• /
• 제9권3호
• /
• pp.498-503
• /
• 2005

Turbine Load Set Motor장치는 노후화 된 화력 발전소에서 출력 부하를 결정하는 중요한 장치로서, Motor를 가변하면서 발전 출력 부하를 조정하게 된다. 이러한 종래 발전시스템에서는 Set Up Range를 운영자가 수동으로 조작한 Set Up값에 따라 Motor를 회전시키게 되며, Motor를 포함한 내부적 동작에 의해서 발전 출력 부하 결정이 이루어지게 된다. 따라서 본 논문에서는 수동적으로 출력부하를 작동되는 Turbine Motor Drive Unit를 대처할 수 있는 Digital Drive Unit 장치를 개발하여 기존 Turbine Load Set Motor 성능을 지닐 수 있는 장비를 구현한다. 또한 구현한 Digital Drive Unit을 바탕으로 발전 출력 부하를 결정하는 기본 기능을 기존 Motor Drive Unit과 연결하여 작동될 수 있도록 제어 알고리즘 구현과 구현된 제어 시스템을 통해 기존 Turbine Load Set Motor Drive와 연결 가능성을 확인한다.

• Journal of Radiation Protection and Research
• /
• 제14권1호
• /
• pp.34-45
• /
• 1989

프랑스의 1300 MWe 급(級) 표준(標準) P'4형 PWR 원전(原電)의 일차냉각재상실사고(一次冷却材喪失事故)(LOCA)시(時) 원전(原電) 주제어가내(主制御家內) 운전원(運轉員)에 대한 고사선(故射線) 피습선량(被濕線量)을 계산하여 주제어실(主制御室)의 체류안전성(滯留安全性)을 평가(評價)하였다. 본(本) 평가(評價)에서 사용(使用)된 제가정(諸假定)은 프랑스의 표준안전성분석보고서(漂準安全性分析報告書)에 따랐다. 본(本) 평가(評價)를 위하여 LOCA 사고시(事故時) 원자로건물외(原子爐建物外)로 방출(放出)되는 방사핵종(放射核種)의 방사능(放射能), 주제어실(主制御室)에서의 체적인자(體積因子) 및 제어실내(制御室內) 운전원(運轉員)의 전신(全身) 및 갑상선(甲狀膳) 피폭선량(被爆線量)을 사고발생후(事故發生後) 30일까지 전산(電算)할 수 있는 간단한 전산(電算)프로그램, COREX를 개발(開發)하였다. 본(本) 연구(硏究)에서 얻어진 계산결과(計算結果)는 대체적으로 프랑스의 EDF(불란서 전력주식회사(電力株式會社) 에서 제안(提案)한 결과(結果)와 대체적으로 잘 일치(一致)하였으나, 전신외부피폭선량(全身外部被爆線量)의 값은 일부(一部) 체적인자(體積因子) 값의 차이로 인(因)하여 일부 편차(偏差)를 보였다.

• Asian Journal of Atmospheric Environment
• /
• 제2권1호
• /
• pp.34-46
• /
• 2008

Emissions inputs for use in air quality modeling of Korea were generated with the emissions inventory data from the National Institute of Environmental Research (NIER), maintained under the Clean Air Policy Support System (CAPSS) database. Source Classification Codes (SCC) in the Korea emissions inventory were adapted to use with the U.S. EPA's Sparse Matrix Operator Kernel Emissions (SMOKE) by finding the best-matching SMOKE default SCCs for the chemical speciation and temporal allocation. A set of 19 surrogate spatial allocation factors for South Korea were developed utilizing the Multi-scale Integrated Modeling System (MIMS) Spatial Allocator and Korean GIS databases. The mobile and area source emissions data, after temporal allocation, show typical sinusoidal diurnal variations with high peaks during daytime, while point source emissions show weak diurnal variations. The model-ready emissions are speciated for the carbon bond version 4 (CB-4) chemical mechanism. Volatile organic carbon (VOC) emissions from painting related industries in area source category significantly contribute to TOL (Toluene) and XYL (Xylene) emissions. ETH (Ethylene) emissions are largely contributed from point industrial incineration facilities and various mobile sources. On the other hand, a large portion of OLE (Olefin) emissions are speciated from mobile sources in addition to those contributed by the polypropylene industry in point source. It was found that FORM (Formaldehyde) is mostly emitted from petroleum industry and heavy duty diesel vehicles. Chemical speciation of PM2.5 emissions shows that PEC (primary fine elemental carbon) and POA (primary fine organic aerosol) are the most abundant species from diesel and gasoline vehicles. To reduce uncertainties in processing the Korea emission inventory due to the mapping of Korean SCCs to those of U.S., it would be practical to develop and use domestic source profiles for the top 10 SCCs for area and point sources and top 5 SCCs for on-road mobile sources when VOC emissions from the sources are more than 90% of the total.

• 한국해양공학회지
• /
• 제29권2호
• /
• pp.191-198
• /
• 2015

In this study, we proposed a new type of dual-buoy wave energy converter (WEC) exploiting multi-resonance and analyzed the experimental results from a model test in a 2-D wave flume. A dual-buoy WEC using multi-resonance has two advantages: high efficiency at the resonant frequencies and the potential to extend the frequency range available to extract wave power from the WEC. The suggested WEC was composed of an outer buoy and an inner buoy sliding vertically inside the outer buoy. As the power take-off device, a linear electric generator (LEG) consisting of permanent magnets and coils fixed at each buoy was adopted. Electricity was produced by the relative heave motion between the two buoys. To search for the optimal shape of a dual-buoy WEC, we conducted experiments on the heave motion of a two-body system in regular waves without an LEG installed. Model tests with six combinations of experimental models were conducted in order to find the motion characteristics of a dual-buoy WEC. It was found that model 2, which included a ring-shaped appendage to move the resonant frequency of the outer buoy toward a high value, showed a higher relative heave response amplitude operator (RAO) curve than model 1. In addition, the double-peak shape of the heave RAO curve shown for model 2 indicated the extension of the frequency range for extracting wave power in irregular waves.

• 전기학회논문지
• /
• 제65권8호
• /
• pp.1326-1333
• /
• 2016

It is important to clear the fault and prevent resulting in damage to power system. Although the frequency of generator internal fault is relatively low, it can lead to incalculable damage to power system as well as generator. Especially, loss of field on generator can cause the generator to lose synchronism for a short time if it is not removed promptly. Therefore, it is needed to conduct research on loss of field relay for detecting or clearing the loss of field. However, the setting of the relay may vary in generator operator or engineer, and the relay is not coordinated well with other elements associated with loss of field. In this paper, we address specifically the coordination of positive offset mho loss of field relay which is one of the protection schemes for loss of field. Computer simulations are performed by using ElectroMagnetic Transients Program-Restructured Version (EMTP-RV) based on actual data.