• 한국물환경학회지
• /
• 제35권1호
• /
• pp.9-18
• /
• 2019

Recently, it was realized that a significant portion of pollution from urban areas originates from non-point sources such as construction sites, washoff from impervious surfaces, and sewage input from unsewered areas and combined sewer overflows. Especially, Urban stormwater runoff is one of the most extensive cause of the deterioration of the water quality in streams located in urban area. The objective of this study was to investigate runoff characteristics of non-point pollutants source at the urban area in the Suyeong River. Water quality variations were investigated at two points of Suyeong River during a period of 10 rainfall events. Concentration difference of non-point pollution source appeared big by precedent number of days of no rainfall. In addition, Event mean Concentration (EMCs) that well represents runoff characteristics of storm water during rainfall, was calculated, and runoff pollutants loading was also examined. The probability distribution of EMCs of BOD, COD, TOC, T-N, T-P, and TSS were analyzed and the mean values of observed EMC and the median values of estimated EMCs compared through probability distribution. Other objectives of this study were the characterization of discharge from non-point source, the analysis of the pollutant loads and an establishment of a management plan for non-point source of Suyeong River. Also, It was established that the most important thing for the administration of non-point pollution source is to come up with the solution for the reduction of effluent at the beginning.

• Ecology and Resilient Infrastructure
• /
• 제7권4호
• /
• pp.294-299
• /
• 2020

본 연구에서는 팔당 상수원 보호구역내 적정 도로비점오염 저감시설의 계획을 위해 대상 도로구간의 현장조사를 통해서 보호구역내 도로의 특성을 파악하고 이에 적용가능한 도로를 선정하고 시설을 시범적용하여 그 유효성을 검증하였다. 팔당 상수원 보호구역은 도로주변 토양의 배수등급이 높아 침투시설을 지양하고 도로사면을 통한 자연적인 오염원 저감방법을 적용하는 것이 적정하다. 앞으로 도로비점저감시설의 계획 및 설계에서 대상도로의 특성에 대한 분석 후 저감계획을 세우는 것이 적정하며 이는 관련 규정 및 설계 기준에도 반영되어야 할 것이다.

• 한국항공우주학회지
• /
• 제38권10호
• /
• pp.979-984
• /
• 2010

GPS/Galileo 통합 수신기를 사용하는 사용자는 특정 측위 시스템에 대한 의존도를 줄이고, 개선된 성능의 PNT 서비스를 제공받을 수 있을 것으로 예상된다. 그러나 사용자들은 GPS와 Galileo, 두 시스템 간의 서로 다른 시각 척도를 사용함으로써 발생하는 문제(즉, GGTO)를 해결해야만 한다. GGTO는 측위 서비스를 요구하는 항법용 수신기뿐만 아니라 정밀한 시각 서비스를 요구하는 타이밍용 수신기에서도 분석되어야 한다. 본 논문에서는 GPS/Galileo 통합 타이밍용 수신기를 사용할 때에 고려해야 하는 상호운용성 문제를 분석하고, 모의실험을 통해 다양한 가정 하에 시각 측면에서의 성능을 예측하였다. Ashtech 사(社)의 상용 타이밍용 수신기를 사용하여 GPS 실측 데이터를 확보하고, Galileo 데이터를 모사한 후에, 타이밍용 환경에 적합한 실험 시나리오를 구성하여, 시나리오 별시각 측면에서의 성능을 평가하였다.

• Journal of Electrochemical Science and Technology
• /
• 제7권2호
• /
• pp.146-152
• /
• 2016

A combined system with PEMFC and reformer is introduced and optimized for the real use of this kind of system in the future. The hydrogen source to operate the PEMFC system is methanol, which needs two parts of methanol reforming reaction and preferential oxidation (PROX) for the hydrogen fuel process in the combined operation PEMFC system. With the optimized methanol steam reforming condition, we tested PROX reactions in various operation temperature from 170 to 270 ℃ to investigate CO concentration data in the reformed gases. Using these different CO concentration, PEMFC performances are achieved at the combined system. Pt/C and Ru promoted Pt/C were catalysts were used for the anode to compare the stability in CO contained gases. The alloy catalyst of PtRu/C shows higher performance and better resistance to CO than the Pt/C at even high CO amount of 200 ppm, indicating a promotion not only to the activity but also to the CO tolerance. Furthermore, in a system point of view, there is a fluctuation in the PEMFC operation due to the unstable fuel supply. Therefore, we also modified the methanol reforming by a scaled up reactor and pressurization to produce steady operation of PEMFC. The optimized system with the methanol reformer and PEMFC shows a stable performance for a long time, which is providing a valuable data for the PEMFC commercialization.

• 대한조선학회논문집
• /
• 제51권2호
• /
• pp.122-129
• /
• 2014

Identification of the whipping response out of the combined wave-vibration response of a flexible sea going vessel is one of the most interesting research topic from ship designer's point of view. In order to achieve this goal, a novel methodology based on the wavelet cross-correlation technique was proposed in this paper. The cross-correlation of the wavelet power spectrum averaged across the frequency axis was introduced to check the similarity between the combined wave-vibration response and impulse response. The calculated cross-correlation of the wavelet power spectrum was normalized by the auto-correlation of the each spectrum with zero time lag, eventually providing the cross-correlation coefficient that stays between 0 and 1, precisely indicating the existence of the impulse response buried in the combined wave-vibration response. Additionally, the weight function was introduced while calculating the cross-correlation of the two spectrums in order to filter out the signal of lower frequency so that the accuracy of the similarity check becomes as high as possible. The validity of the proposed methodology was checked through the application to the artificially generated ideal combined wave-vibration signal, together with the more realistic signal obtained by running 3D hydroelasticity program WISH-Flex. The correspondence of the identified whipping instances between the results, one from the proposed method and the other from the calculated slamming modal force, was excellent.

• 한국위성정보통신학회논문지
• /
• 제5권2호
• /
• pp.19-24
• /
• 2010

통신해양기상위성(COMS)은 통신, 해양, 기상 탑재체를 장착하고 3개의 임무를 수행하는 복합 정지궤도 위성이다. COMS는 기상탑재체 MI와 해양 탑재체 GOCI가 관측 후 전송하는 원시 데이터를 지상국에 전송하고 지상국에서 처리된 기상 데이터를 최종 사용자국에 중계하는 기능을 갖는 기상해양자료송수신계(MODCS)가 있다. 여기서 시스템 관점에서 관측 데이터 SD 신호와 중계 신호를 전송하는 L-대역 송신 안테나는 MI 탑재체와 기상탑재체와 함께 COMS 위성의 지구패널에 장착시 안테나 합성 이득을 예측하도록 요구되어진다. 우선 주어진 요구 사항에 대해 L-대역 송신 안테나 설계 및 해석이 수행된다. 설계된 안테나를 지구패널에 장착 후 3가지 다른 해석 방법을 사용하여 합성이득 해석이 수행된다. 얻어진 안테나 이득들은 3가지 다른 해석 방법 사이에 매우 유사한 결과를 제공하는 것을 확인하였으며 최종적으로 0.5 dB 이하의 안테나 이득 열화가 추정되어진다.

• 대한한방소아과학회지
• /
• 제15권2호
• /
• pp.75-83
• /
• 2001

Background and method : The Cervi cornu parvum for children patients have been widely used nowadays: however, there have been no reports about the children patients' conditions and the parents' responses. To investigate these things, the questionnaires were used for the children patients(the ages between 0 and 15) who took the herbal medication combined with Cervix cornu parvum and their parents from January 1, 2000 to June 31 at the Dong-seo oriental Hospital. The chief complaints such as common cold, dyspepsia of using Cervi cornu parvum were divided into five categories and the changes were observed, scoring each stages. Besides, the quantity of taking herbal medication combined with Cervix cornu parvum, the expectancy, the satisfaction, the continual favor were included in the questionnaires. The result : 1. The trackable sample was 53: male infants 34(64.2%), female infants 19(35.8%). There is no differences between genders in the treating results. The treating results were increased after taking herbal medication combined with Cervi cornu parvum 2. When age is grouped by three categories(0-1, 2-6, 7-14 ages), the statistics shows that the treating results have no differences between each group(P>0.05) Regardless of the ages, the treats have correlated.(P<0.05) 3. When each symptoms made treated one case are analyzed, there have been correlations between the taking herbal medication combined with Cervi cornu parvum and recovery.(P<0.05) 4. The treating result have not affected by the expectancy.(P>0.05) Each group(good, moderate, poor) showed the recovery after the treatment.(P<0.05) 5. When the satisfaction divided into three groups(good, moderate, poor) there existed differences between groups.(P<0.05) Especially, the group with high expectancy increased the treatment. 6. About the recognition of herbal medication combined with Cervi cornu parvum is like this: the health refreshment, ordinary taking whenever turning-point of seasons comes, treatment, disbelieving the overdose of herbal medication combined with Cervi cornu parvum, disbelief about the security of the medicine such as fake medicine, mad cow diseases, the imported medicine, ignorance about the way of taking the medicine.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• 제16권4호
• /
• pp.281-292
• /
• 2016

The proposed scheme is based on the modified perturb and observe (P&O) algorithm combined with the sliding mode technique. A modified P&O algorithm based sliding mode controller is developed to study the effects of partial shade, temperature, and insolation on the performance of maximum power point tracking (MPPT) used in photovoltaic (PV) systems. Under partially shaded conditions and temperature, the energy conversion efficiency of a PV array is very low, leading to significant power losses. Consequently, increasing efficiency by means of MPPT is particularly important. Conventional techniques are easy to implement but produce oscillations at MPP. The proposed method is applied to a model to simulate the performance of the PV system for solar energy usage, which is compared to the conventional methods under non-uniform insolation improving the PV system utilization efficiency and allowing optimization of the system performance. The modified perturb and observe sliding mode controller successfully overcomes the issues presented by non-uniform conditions and tracks the global MPP. Compared to MPPT techniques, the proposed technique is more efficient; it produces less oscillation at MPP in the steady state, and provides more precise tracking.

• Journal of Astronomy and Space Sciences
• /
• 제32권4호
• /
• pp.403-409
• /
• 2015

The Quasi-Zenith Satellite System (QZSS), a dedicated regional Japanese satellite system currently under development, was designed to complement the performance of the Global Positioning System (GPS). The high elevation angle of the QZSS satellite is expected to enhance the effectiveness of GPS in urban environments. Thus, the work described in this paper, aimed to investigate the effect of QZSS on GPS performance, by processing the GPS and QZSS measurements recorded at the Bohyunsan reference station in South Korea. We used these data, to evaluate the satellite visibility, carrier-to-noise density (C/No), performance of single point positioning, and Dilution of Precision (DOP). The QZSS satellite is currently available over South Korea for 19 hours at an elevation angle of more than 10 degrees. The results showed that the impact of the QZSS on users' vertical positioning is greatest when the satellite is above 80 degrees of elevation. As for Precise Point Positioning (PPP) performance, the combined GPS/QZSS kinematic PPP was found to improve the positioning accuracy compared to the GPS only kinematic PPP.

• Radiation Oncology Journal
• /
• 제1권1호
• /
• pp.103-109
• /
• 1983

47 out of 56 cases of intact uterine cervix cancer treated by radiation at the Hanyang University Hospital were followed 18 months or more after treatment. (7 patients died before 18 months, 2 cases lost to follow-up). Age distribution reveal 5 cases in 30's, 18 cases in 40's, 17 cases in 50's, 7 cases in 60's. Histologically, all cases were squamous cell type except one case of adenocarcinoma. 1. 45 cases were treated by combined external Co-60 irradiation and intracavitary irradiation by Cs-137 small sources. 1 case was treated by external irradiation only, and 1 case by intracavitary only. 2. Rectal injuries were observed in 13 cased (27.6%), 4 cases in Grade 1, 8 cased in Grade 2 and 1 cases in Grade 3 which needed surgical management. 3. Average intervals of rectal injury following treatment was 9.2 months varying from 5 to 15 months. 4. Relation between rectal injury and point A dose reveal 6 cases between 7000-7999 rad and 6 cases between 8000-8999 rad and 1 case above 9000 rad. Even though there is no direct relation between point A dose and rectal injury, it is expected that rectal injury increases as point A dose increase. 5. In the normal condition, rectal injury can't be attributed to one major cause. Radiation dose, small source distribution, general condition of patients, local anatomy of the individual patient, history of PID and previous surgery, all play complex roles.