• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.416-416
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• 2022

RCP(Representative concentrate pathways) 기후변화 시나리오에서는 2100년까지 연강 강수량과 강우지속시간이 지속적으로 증가할 것으로 예측하고 있다. 이에 도시지역의 하천 범람 및 내수 침수 예방을 위해 방재성늑목표의 상향조정과 방재 인프라의 설계년수 재조정 등에 대한 논의가 진행되고 있다. 하지만 수재해 예방을 위한 강우설계기준에서는 무강우 지속시간의 설정을 확보할 수 있는 최대 규모의 모집단을 통해 산정하는 방식으로 제시되고 있어 최근 기후변화로 인한 강우특성의 변화가 반영되기에 어려움이 있다. 본 연구에서는 부산광역시 강우자료의 모집단을 10년, 20년, 30년으로 구분하여 자기상관계수(Autocorrelation coefficient, AC) 분석, 변동계수(Coefficient of variation, CV) 분석, 연평균 강우사상 발생 개수(Average annual number of rainfall event, NRE) 분석 방법을 적용하여 비교 분석을 수행하였다. 그 결과, 자기상관계수 분석 방법과 변동계수 분석 방법에서는 모집단의 규모가 클수록 튀는 자료를 상쇄하여 안정적인 결과를 나타내는 반면, 연평균 강우사상 발생 개수를 확인 하였을 때는 대상기간에 큰 영향을 받지 않는 것으로 확인되었다. 또한, 모집단의 규모가 클수록 무강우 지속시간이 길어지는 것으로 분석되어 기후변화로 인한 최근의 강우특성을 반영하기 위해서는 모집단의 규모를 크게 잡는 것이 효과적이지 않을 수 있다는 점을 확인하였다. 이는 강우자료 분석 시 분석방법 및 모집단의 규모를 달리하여 무강우 지속시간을 산정해보고, 설계 목적에 따라 적정한 의사결정이 필요함을 시사한다.

• Journal of Korea Water Resources Association
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• v.56 no.12
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• pp.855-869
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• 2023

Low Impact Development (LID) technology has been attracting attention as a countermeasure to solve frequent flood damage in urban areas. LID involves recovery of the natural circulation system based on infiltration and storage capacity at the site of rainfall runoff, to protect the aquatic ecosystem from the effects of urbanization. Bioretention as an element of LID technology reduces outflow through storage and infiltration of storm water runoff, and minimizes the effects of non-point pollutants. Although LIDs are being studied extensively, the amount of quantitative research on small watersheds with bioretention has been inadequate. In this study, a bioretention model was constructed in a small watershed using Korea-Low Impact Development Model (K-LIDM), which was conducted quantitative hydrologic analysis. We anticipate that the results of the analysis will be used as reference data for future bioretention research related to watershed characteristics, vegetation type, and soil condition.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.21-26
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• 2024

Urban air mobility (UAM) is being considered as an alternative to transportation in urban areas where traffic congestion is increasing. It is judged that it will be difficult to manage the complex UAM operation environment with the existing Air Traffic Service, which is a person-centered service. Therefore, an advanced information processing-based traffic management system for UAM (UATM) is needed. Airspace management is essential to establish a systematic UAM traffic management (UATM) environment. In particular, the establishment of exclusive corridors where UAM aircraft can operate safely can provide opportunities to operate UAM aircraft without violating the minimum flight altitude regulations. This study conducted an empirical analysis using a helicopter of similar size to UAM to establish the cross-track dimension of the corridor for UAM operation. The research results can be used as a guideline when designing UAM corridors.

• Journal of the Korean Institute of Landscape Architecture
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• v.44 no.1
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• pp.107-118
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• 2016

The Seoul metropolitan government announced an open design competition for reconfiguring the annex building of the National Tax Service Building site on Sejong-daero as a space for citizens to commemorate the 70th anniversary of Korea's liberation. The site, built during the Japanese colonial period, has been in use ever since. This study, as one of the entries for the competition, described the strategy and design contents by drawing the concept and main points of the design through an analysis of the historical context of the site. As the guidelines instructed to consider the value of the Sejong-daero area and the cultural heritage through a comprehensive analysis, this study specified the site as a place connecting the past, present and future. Since the foundation of the Joseon dynasty, the Korean Empire and the Japanese colonial period, Sejong-daero has been a main site for important events and activities along with the change of the city structure. Jungdong, to the rear of the site, was a place for adopting new culture during the beginnings of modern Korea, while adjacent places like Duksugung, the Anglican church, and the Seoul City Council building have also been historic urban landscapes of the historical layers of time as the city has changed. When Gojong announced the Korean Empire, the city structure was remodeled with this site as the center along with Sogong-ro, Wongudan and so forth. In this study, public interest stated in the guidelines was focused and the relevance of the road and the plaza was considered from the view of an historic urban landscape by a comprehensive analysis with Sejong-daero as the center. The restoration of public interest was to be drawn as the concept of the object site by considering the current status and the change around the site and Jungdong at the rear. Returning the site to the public is ambiguous with the relevance of the restoration of public interest and as the symbol of the idea of the Korean Empire by Gojong's announcement. The object site, having the characteristic of being returned to the public, must ensure public interest and therefore the design strategy has been established with the keywords of openness, connection and void. As a result of a review of the alternatives, a plan for a square has an 8% slope, just as the original site does, and provides ramps for convenient access for all, including the disabled and the elderly, and is connected to the grounds adjacent. No construction is allowed at the terrace square of the Anglican church level and the main square connected to the pedestrian street, so a variety of modern city utilization can be done. The value of the site at which this design is aimed shall be given back to the public with the concepts of modern democracy, independence, and the vision of Gojong by reinterpreting the space from a modern viewpoint. This study focused on the processes of establishing a main concept and strategy rather than the content of the design details, and the suggestion is meaningful in that the design for the object site with historic backgrounds and the layers of time can continue to be grown.

• Journal of Korean Society of Transportation
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• v.26 no.3
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• pp.233-243
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• 2008

Recognition for the importance and roles of public transportation is increasing because of traffic problems in many cities. In spite of this paradigm change, previous researches related with public transportation trip assignment have limits in some aspects. Especially, in case of multimodal public transportation networks, many characters should be considered such as transfers. operational time schedules, waiting time and travel cost. After metropolitan integrated transfer discount system was carried out, transfer trips are increasing among traffic modes and this takes the variation of users' route choices. Moreover, the advent of high-technology public transportation card called smart card, public transportation users' travel information can be recorded automatically and this gives many researchers new analytical methodology for multimodal public transportation networks. In this paper, it is suggested that the methodology for establishment of brand new multimodal public transportation networks based on computer programming methods using transportation card data. First, we propose the building method of integrated transportation networks based on bus and urban railroad stations in order to make full use of travel information from transportation card data. Second, it is offered how to connect the broken transfer links by computer-based programming techniques. This is very helpful to solve the transfer problems that existing transportation networks have. Lastly, we give the methodology for users' paths finding and network establishment among multi-modes in multimodal public transportation networks. By using proposed methodology in this research, it becomes easy to build multimodal public transportation networks with existing bus and urban railroad station coordinates. Also, without extra works including transfer links connection, it is possible to make large-scaled multimodal public transportation networks. In the end, this study can contribute to solve users' paths finding problem among multi-modes which is regarded as an unsolved issue in existing transportation networks.

• Journal of Korean Society of Transportation
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• v.19 no.4
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• pp.35-47
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• 2001

Traffic represents one of the largest sources of primary air pollutants in urban area. As a consequence. numerous abatement strategies are being pursued to decrease the ambient concentration of pollutants. A characteristic of most of the these strategies is a requirement for accurate data on both the quantity and spatial distribution of emissions to air in the form of an atmospheric emission inventory database. In the case of traffic pollution, such an inventory must be compiled using activity statistics and emission factors for vehicle types. The majority of inventories are compiled using passive data from either surveys or transportation models and by their very nature tend to be out-of-date by the time they are compiled. The study of current trends are towards integrating urban traffic control systems and assessments of the environmental effects of motor vehicles. In this study, a methodology of motor vehicle emission calculation by using real-time traffic data was studied. A methodology for estimating emissions of CO at a test area in Seoul. Traffic data, which are required on a street-by-street basis, is obtained from induction loops of traffic control system. It was calculated speed-related mass of CO emission from traffic tail pipe of data from traffic system, and parameters are considered, volume, composition, average velocity, link length. And, the result was compared with that of a method of emission calculation by VKT(Vehicle Kilometer Travelled) of vehicles of category.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.3
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• pp.1-14
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• 2008

Mass transit information should contribute many benefits to users. Especially transportation information technology is developing highly with information technology in Korea recently. Hereafter it is expected to provide customized transportation information to users individually with the advent of ubiquitous age in earnest. This public transportation information service can be realized by path finding algorithms in public transportation networks including travel and transfer attributes. In this research, multi objectives such as travel time, transfer time, and number of transfer and so on are constructed with the primary facts influencing users. Moreover, the method reducing user's path finding alternatives arbitrarily is proposed by selecting the best alternative which provides maximum utility to users among non dominated paths. Therefore, the ultimate goal of this study proposes a multi objective shortest paths finding algorithm which can take into account multiple user classes in a transit network with multiple travel modes. The proposed algorithm is demonstrated based on the two case studies - a small toy network and the large-scaled Seoul Metropolitan subway network.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.31-44
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• 2004

The study of Estimation model for the short-term travel time prediction. There is a different solution which has predicted the link travel time to solve this problem. By using this solution, the link travel time is predicted based on link conditions from time to time. The predicated link travel time is used to search the shortest path. Before providing a dynamic shortest path finding, the prediction model should be verified. To verify the prediction model, three models such as Kalman filtering, Stochastic Process, ARIMA. The ARIMA model should adjust optimal parameters according to the traffic conditions. It requires a frequent adjustment process of finding optimal parameters. As a result of these characteristics, It is difficult to use the ARIMA model as a prediction. Kalman Filtering model has a distinguished prediction capability. It is due to the modification of travel time predictive errors in the gaining matrix. As a result of these characteristics, the Kalman Filtering model is likely to have a non-accumulative errors in prediction. Stochastic Process model uses the historical patterns of travel time conditions on links. It if favorably comparable with the other models in the sense of the recurrent travel time condition prediction. As a result, for the travel time estimation, Kalman filtering model is the better estimation model for the short-term estimation, stochastic process is the better for the long-term estimation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.45-52
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• 2004

There are many cities installing ITS(Intelligent Transportation Systems) and running TMC(Trafnc Management Center) to improve mobility and safety of roadway transportation by providing roadway information to drivers. There are many devices in ITS which collect real-time traffic data. We can obtain many valuable traffic data from the devices. But it's impossible to avoid missing traffic data for many reasons such as roadway condition, adversary weather, communication shutdown and problems of the devices itself. We couldn't do any secondary process such as travel time forecasting and other transportation related research due to the missing data. If we use the traffic data to produce AADT and DHV, essential data in roadway planning and design, We might get skewed data that could make big loss. Therefore, He study have explored some imputation techniques such as heuristic methods, regression model, EM algorithm and time-series analysis for the missing traffic volume data using some evaluating indices such as MAPE, RMSE, and Inequality coefficient. We could get the best result from time-series model generating 5.0$\%$, 0.03 and 110 as MAPE, Inequality coefficient and RMSE, respectively. Other techniques produce a little different results, but the results were very encouraging.

• Journal of Korean Society of Transportation
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• v.20 no.1
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• pp.7-18
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• 2002

To activate public transportation service, Bucheon City built Bus Information System based on Beacon type, and operates it for no.22 line. This research analyzes an effect of BIS operations, and mainly it analyzes far reliability evaluation of bus arrival time information and passenger satisfaction about BIS. As results of reliability evaluation of arrival time information service, it is proven to be practically inappropriate to use as arrival time data because it is not only travel time between each bus stop but also previous travel time history data. In order to improve this matter, neural network model was evaluated as the most outstanding one as result of experiment in applying current arrival time Prediction model. This research cannot help limiting for evaluation of operation effect in Bucheon City because there is no Bus Information System based on GPS type in Korea. For the future ITS model city, in the case of building ITS model city based on GPS type, it is possible to compare two systems relatively. In addition to that, fur the consideration of reliability of bus arrival time information, it is required to develop Predictable model and research factors that affect to bus operation.