• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.34 no.1
• /
• pp.1-10
• /
• 2016

Seoul, a mega city, contains many features of the modern city. When the disaster or emergency occurs in Seoul, the place for shelter is required for evacuation urgently. There are currently the numbers of shelters in Seoul City, which can hold the twice more capacity of population of Seoul. However, the population distribution fluctuation in the day and the night needs to be considered. Therefore, in order to analyze the actual capacity of shelter, it is necessary to consider the dynamic characteristics of population distribution in the metropolitan area. In the study, the substantial accessibility and the capacity of shelters in Seoul were analyzed by the floating population data of the metropolitan area. The accessibility of shelter was investigated through a network analysis that includes the pedestrian road data, while the capacity of shelter was analyzed by the local differences of daytime population distributions. Finally it was possible to identify the vulnerable areas on the basis of the distribution of shelter in the region.

• Journal of Korean Society of Transportation
• /
• v.27 no.5
• /
• pp.29-37
• /
• 2009

As the level of the ambient air quality becomes increasingly important, transportation management strategies tend to incorporate air quality standards into their measure of effectiveness. However, previous research efforts did not pay much attention to the empirical relationships between traffic volume and air quality, potentially due to the lack of data. With this background, this study investigates the relationship using Seoul's existing traffic and air quality monitoring data collected over the period of three years, from 2005 through 2007. In particular, those paired monitoring sites with a distance of less than one kilometer apart were utilized, targeting the emissions of CO, NO, $NO_2$, and $PM_{10}$. As a result, in general the data of two monitoring systems exhibited lower correlations, $NO_2$ showing a relatively higher correlation with traffic volumes than other emissions. In addition, it was found that the degree of correlation can be higher for the data obtained over the morning time period, 6am-9am, and the day after rainy days.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.14 no.1
• /
• pp.103-111
• /
• 2015

The purpose of this study is to estimate the appropriate Demand Responsive Transport (DRT) fare for bus users upon introduction of the system, which is to improve ridership on economically non-profitable routes and to conform to the mobility right of those living in presently non-serviced rural areas. For this, a stated preference (SP) survey was adopted to assess respondents' preferences regarding DRT introduction, while the contingent valuation method (CVM) was used to calculate their willingness to pay (WTP) for DRT services. The analysis results show that, compared to the existing bus services with a 1,000 won bus fare, the value of DRT is considered to be 38.85%, 31.03% and 30.12% higher in terms of overall assessment, usability and convenience, respectively. The results of this study are expected to facilitate the decision making aimed at setting the appropriate DRT fare and implementing a DRT system that meets sustainability requirements.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.402-402
• /
• 2019

최근 기후변화에 따른 용수사용량의 계절별 변화가 나타나고 있다. 따라서, 효율적인 용수 관리에 대한 관심은 배수지 및 송수 시스템의 운영을 넘어 정수장의 운영에서도 그 변화가 나타나고 있다. 수질관리 측면에 다소 집중되었던 정수장 운영의 중요도는 수량을 함께 관리하는 방향으로 변화할 것으로 전망되며, 따라서 취수 단계에서부터 용수 공급의 전 과정을 고려하는 지능형 정수장 관리시스템이 주목받고 있다. 상수도 공급을 위한 정수장의 운영은 크게 원수의 취수 및 도수, 정수처리, 정수된 용수의 저장, 배수 및 급수의 과정으로 구분할 수 있다. 이때, 원수의 취수와 도수, 정수처리 과정에는 상대적으로 긴 시간이 소요되므로, 정수장의 운영 관리자는 이러한 지연시간을 감안해서 배수지의 상태를 예측하여 취수계획을 결정해야 한다. 한편, 정수장 시설을 운영하기 위해서는 전력이 소모되며, 산업전력 단가는 시간대별 변동폭이 큰 것으로 알려져 있다. 따라서, 정수장의 효율적인 운영을 위해서는 용수의 수요예측과 배수지 수위변동, 취수 및 정수설비의 규모 등을 고려하는 동시에, 전력 단가가 낮은 시간대에 설비를 집중적으로 운영할 수 있는 계획을 수립해야 한다. 본 연구에서는 선형계획법(Linear Programming, LP)을 이용하여, 수요예측을 바탕으로 장기취수계획을 수립하기 위한 방안을 세 가지로 구분하였으며, 각각의 장단점을 다음과 같이 예상하였다. 1) 24시간 간격으로 시간당 취수계획을 수립하는 최적화 방안, 2) 24시간의 시간당 취수계획을 1시간 간격으로 수립하는 실시간 최적화 방안, 3) 전체 모의기간 동안의 시간당 취수계획을 한번에 수립하는 최적화 방안. 24시간 간격 최적화는 수립 및 적용이 간단한 반면, 실시간 수요변화를 고려할 수 없어 단위시간(24시간) 후반부의 최적화 효율이 떨어지는 단점이 있다. 1시간 간격의 실시간 최적화는 수요변화를 가장 정확히 반영하는 반면, 최적화 수행 횟수가 증가하는 단점이 있다. 전체 모의기간 최적화는 장기 수요예측을 고려한 탄력적 취수계획을 수립하는 반면, 수요예측의 불확실성에 따른 오차 발생위험이 크다. 본 연구에서는 국내 H 정수장을 대상으로 각각의 최적 취수계획 수립 방안을 정수장 운영의 안정성, 탄력성, 경제성 등을 기준으로 비교, 분석하였다.

• Solar Energy
• /
• v.20 no.1
• /
• pp.45-54
• /
• 2000

Five direct/diffuse decomposition models were validated using the eight years data set of direct normal beam insolation measured in Seoul. The comparison has been performed In terms of the widely used statistical indicators such as MBE, RMSE, CV(RMSE), t-Statistic and Degree of Agreement. Result indicates that most of the correlations exhibit a tendency to underestimate the direct normal beam insolation except Bouguer's model. Most of big discrepancies between the measured and the predicted values was mainly shown in near the sunrising and the sunset period. Even though the investigated five models showed fairly large disagreement for the measured values by 34%$\sim$48% of CV(RMSE), Udagawa's correlation which includes the effect of solar altitude variation appears to performs always better in every statistical error tests.

• Journal of Digital Convergence
• /
• v.19 no.2
• /
• pp.365-371
• /
• 2021

In this paper, the writer studies the lighting technology and types used in urban night lighting performance. With the continuous change and innovation of life style in today's society, the multiple functions of the city continue to develop. At present, urban night lighting is not limited to lighting the landscape in the daytime by lighting tools. It uses new digital lighting technology to deduce innovative and constantly changes digital nightscape. In this way, through the integration of urban nighttime lighting and modern digital art, the city's brand image can be improved and its economic development will also be affected. In this way, through the integration of urban nighttime lighting and modern digital art, the city's brand image can be improved and its economic development will also be affected. With the development of innovative lighting technology, urban night scene will provide more rich experience in media design.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2021.06a
• /
• pp.407-407
• /
• 2021

토양수분량은 그 양은 작지만 다양한 수문현상에 관여하는 주요한 수문인자 중 하나이다. 특히, 강우, 유출, 홍수 및 가뭄 등과 직접적인 연관이 있어 국내에서도 그 중요성이 점차 강조되고 있다. 일찍이 해외에서는 토양수분량 위성자료나 관측기기의 검증 및 교정을 위해 다수의 지상 관측소를 운영해왔으며, ISMN(International Soil Moisture Network)과 같은 기관을 통해 자료의 취합 및 품질관리, 배포 등도 활발하게 이루어지고 있다. 최근 국내에서도 최신 관측기기의 도입이나 수자원위성의 개발 등 토양수분량에 관한 연구가 점차 활발하게 이루어지고 있으며, 위성자료와 관측기기의 검증 및 교정을 위한 지상관측소도 점차 확대되고 있는 추세이다. 하지만, 국내 지상관측소는 현재 다양한 기관과 단체에 의해 운영되고 있으며, 품질관리 기준이 통일되어 있지 않아 자료의 접근 및 활용 측면에서 개선이 필요한 실정이다. 이에 한국수자원조사기술원은 국내 환경에 맞는 품질관리 기준을 제시하고, 자료의 접근성 및 활용성 개선의 토대를 마련하고자 품질관리 시스템을 개발하고 있다. 본 연구는 정량화된 품질관리 기준을 바탕으로 spike를 판별하는 알고리즘에 대한 성능평가를 다루고 있으며, 청미천 토양수분량 관측소 2020년 자료에 임의의 튀는 값(spike)을 추가하고, 해당 이상치의 검출여부를 확인하는 방식으로 진행되었다. 각각의 지점자료에서 강우사상 중 하강부, 무강우기간 중 하강부를 1개씩 선정하고, 해당 구간에 positive spike를 추가한 case와 negative spike를 추가한 case를 생성해 강우조건 및 spike 유형에 따른 검출성능 차이를 평가했다. 평가 결과, 강우기간 검출률 84.3%, 무강우기간 검출률 96.3%로 강우조건에 따른 성능차이가 명확하게 나타났으며, positive spike는 91.7%, negative spike는 88.9%로 spike 유형에 따른 검출성능차이는 미미했다. 강우조건과 spike 유형을 동시에 고려했을 때는 무강우기간의 positive spike가 98.2%로 가장 높은 검출률을 보인 반면에 강우기간의 negative spike는 83.3%로 가장 낮은 검출률을 보였다. 알고리즘이 검사시간대를 중심으로 24시간 동안의 토양수분량 변화를 감지하기 때문에 강우기간에 검출성능이 저하되는 것으로 판단되며, 이를 개선하기 위해선 강우사상에 따른 유동적인 window size 조절 알고리즘의 추가가 필요할 것으로 판단된다.

• Ecology and Resilient Infrastructure
• /
• v.7 no.4
• /
• pp.227-237
• /
• 2020

Microclimatic data were measured, and the human thermal sensation was analyzed at 10 local climate zones based on the major land cover classification to investigate the thermal environment of urban areas during summer nighttime. From the results, the green infrastructure areas (GNIAs) showed an average air temperature of 1.6℃ and up to 2.4℃ lower air temperature than the gray infrastructure areas (GYIAs), and the GNIAs showed an average relative humidity of 9.0% and up to 15.0% higher relative humidity. The wind speed of the GNIAs and GYIAs had minimal difference and showed no significance at all locations, except for the forest location, which had the lowest wind speed owing to the influence of trees. The local winds and the surface roughness, which was determined based on the heights of buildings and trees, appeared to be the main factors that influenced wind speed. At the mean radiant temperature, the forest location showed the maximum value, owing to the influence of trees. Except at the forest location, the GNIAs showed an average decrease of 5.5℃ compared to GYIAs. The main factor that influenced the mean radiant temperature was the sky view factor. In the analysis of the human thermal sensation, the GNIAs showed a "neutral" thermal perception level that was neither hot nor cold, and the GYIAs showed a "slightly warm" level, which was a level higher than those of the GNIAs. The GNIAs showed a 3.2℃ decrease compared to the GYIAs, except at the highest forest location, which indicated a half-level improvement in the human thermal environment.

• Ecology and Resilient Infrastructure
• /
• v.3 no.1
• /
• pp.46-53
• /
• 2016

This study was conducted to analyze the effect of the different land covers of an urban park (Hyowon park) in downtown Suwon on the urban thermal variations during a hot summer. The effect of the air temperature reduction in the urban park was 4.4%-4.5% for the downtown residence (Maetan-dong). This value was about 0.8% lower than that of the outskirts residence (Sanggwanggyo-dong). The daily mean temperature, daily maximum temperature, summer day and heat wave frequency were measured under the different land covers (cement-block, grass, pine-grass, shading area and mixed forest) showed these values generally decreased under natural land cover types. Daily minimum temperature and tropical night frequency didn't seem to correlate with the land cover types. Means of thermal comfort indices (wet bulb globe temperature, heat index and discomfort index) in the shading area, mixed forest and the pine-grass types were lower than those of cement block and grass types. However the levels of those indices were equal to 'very high' or 'caution' levels in the afternoon (13:00-15:00). In the morning (06:00-08:00), thermal comfort indices of the urban park didn't correlate with land cover types. Therefore, to reduce heat stress and to improve the thermal comfort in urban parks, an increase in the area of natural land cover such as grass, forest and open spaces is required.

• Journal of Environmental Impact Assessment
• /
• v.29 no.3
• /
• pp.182-197
• /
• 2020

This study investigated the home range and characteristics of activities to contribute to the improvement of management techniques and the successful promotion of management policies of invasive nutria, which is a representative invasive species of South Korea. Six individuals were captivated for the study. Remote radio tracking on three of them was carried out followed by the analysis of the results. The average home range of the follow-up individuals were confirmed to be 0.043 ㎢ at MCP 95%, 0.085 ㎢ at K 95%. It was 0.018 ㎢ at K 50%, which is the core space. In 95% MCP, males exhibited the home range with 0.058 ㎢, showed wider home range 0.046 ㎢ than females who showed 0.012 ㎢, and showed a wider home range 0.015 ㎢ more at night than during the day. As a result of comparing the results of this study with the case studies of overseas studies, it is determined that the magnitude of the derived home range is the result of a stable habitat in which the procurement of food resources is smooth and human interference is limited. The daily moved distance of males was larger than that of females, with a maximum moved distance of 1,278 m per day. Activity at the study site is high from around sunset to around 6 A.M., 10 P.M., 7 P.M., 1 A.M., and 5 A.M., and high around sunrise and low during the daytime such as 2 P.M., which reflected the propensity of nocturnal animals to act. The results of this study on the home range and activity in nutria can be used as useful data forimproving the management of invasive alien species for the installation and operation of traps, the spatial setting of controlled areas, and the calculation of the amount ofresources together with a basic understanding of nutria's behaviors in South Korea.