• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.1
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• pp.45-57
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• 2019

The resident characteristics of land-based pollutants were analyzed to manage the pollution sources affecting Suyeong Bay. These characteristics were analyzed using a hydrodynamic model and particle tracking model. Pollutants were represented by particles, and the amount of particles and pollutants was represented proportional. The resident characteristics were analyzed by comparing the amount of pollutant load, resident pollutants, and the ratio of resident pollutants remaining in the bay relative to the incoming load for each the of pollution sources. The order of the pollution sources was as follows, according to the amount of resident pollutants at Suyeong Bay. the Suyeong WasteWater Treatment Plant(WWTP), Nambu WWTP, Suyeong river and so on. The amount of resident pollutants was smaller for small load farther away from the interior of bay. Nambu WWTP had the greatest load among the pollution sources, but it showed the smallest ratio of pollutants remaining in the bay relative to incoming load among the pollution points. The result indicates that pollutants affect sea areas differently according to the characteristics each area and the topographic characteristics of pollution sources.

• Journal of Cadastre & Land InformatiX
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• v.50 no.1
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• pp.231-245
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• 2020

The purpose of this study was to analyze the spatiotemporal characteristics of staying places by deriving the main staying places of the elderly population in Seoul using public transportation card data. For this reason, we used public transportation card data for 7 days from October 12, 2015 to October 18, 2015. As a result of the analysis, 14 places were extracted as the main staying places. It was divided into 5 groups based on the characteristics of the visiting users and concentration time. Most of the staying places showed that the elderly users who lived near the places visited, but in the case of the group where a large number of elderly users visited had relatively wide range of residential distribution. It was possible to confirm that there was a hierarchy. And the concentration time was displayed differently. Most of the staying places' concentration time was between 10 am and 5 pm. However, in the case of Jegi-dong group and Jamsil group had different concentration time. The results of this research provide necessary suggestions for establishing a public transport policy that considers the main stay spaces of the elderly population in Seoul and the stay characteristics of each stay space.

• Digital Contents
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• no.10 s.161
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• pp.88-89
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• 2006

다른 게임 장르에 비해 RPG란 장르는 상대적으로 유저의 평균체류시간이 길다. 이는 RPG의 특성상 FPS나 RTS장르처럼 단판 위주의 게이미 아니라 광활한맵을 이동하면서 사냥과 퀘스트가 끊임없이 반복되기 때문이다. 그러나 같은 RPG라 할지라도 게임마다 특성이 다르기 때문에 평균체류시간은 다르게 나타나고 있다.현재까지 게임마다 평균체류시간이 다르게 나타난다는 것은 잘 알려진 사실이다. 그러나 이에 대한 원인분석이나 체계적인 연구가 부족했던 것 또한 사실. 이는 RPG장르 내 어떤 요인들이 평균체류시간에 영향을 미치는가에 대한 실증분석이 전무한 상태에서 막연한 '감' 에 의한 평가가 대부분이었기 때문이다. 여기서는 지난 5월 30일을 기준으로 게임트릭스에 등록된 86개의 MMORPG중에서 이미 서비스가 종료됐거나 과거 1년 동안 갑작스럼 패치, 업그레이드등으로 데이터 손실이 많았던 게임, 그리고 데이터를 구할 수 없었던 게임들을 제외한 총 51개의 MMORPG를 대상으로 평균체류시간을 분석했다.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.83-88
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• 2011

Holdup characteristics of small bubbles were investigated in a viscous slurry bubble column. The phase holdup of small bubbles was obtained from the knowledge of total bubble(gas) holdup and large bubble holdup, which were measured by mean of static pressure drop method and dual resistivity probe method, respectively. Effects of gas velocity, viscosity of continuous liquid phase and solid fraction in the slurry phase on the small bubble holdup as well as holdups of total bubble(gas) and large bubble in a viscous slurry bubble column. The small bubble holdup increased with increasing gas velocity but decreased with increasing liquid viscosity or solid fraction in the slurry phase. In addition the fraction of small bubble in the total bubble(gas) holdup increased with increasing gas velocity but decreased with increasing liquid viscosity or solid fraction in the slurry phase. It was revealed that the rising velocity of large bubble did not related to the holdup of small bubble in a viscous slurry bubble column.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.67-73
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• 2015

Using a computational fluid dynamics technique, the flow characteristics and particle residence time in a Taylor reactor were studied. Since flow characteristics in a Taylor reactor are dependent on the operating conditions, effects of the inlet flow velocity and reactor rotational speed were investigated. In addition, the particle residence time of $LiNiMnCoO_2$ (NMC), which is a cathode material in lithium-ion battery, is estimated in the Taylor vortex flow (TVF) region. Without considering the complex chemical reaction at the inlet, the effect of Taylor flow was studied. The results show that the particle residence time increases as the rotating speed increased and the flow rate decreased.

• Journal of Advanced Navigation Technology
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• v.23 no.5
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• pp.380-385
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• 2019

This paper is concerned with departure passengers' dwell time analysis using real system data. Previous researches emphasize the importance of dwell time analysis from perspective of airport terminal planning and non-aeronautical revenue. However, short-term airport operation using passengers' dwell time is considered impossible due to absence of passengers' behavior data. Recently, in accordance with the wave of smart airport, world leading airports are systematically collecting passenger data. So there is high possibility of analyzing passengers' dwell time with the data stacked in the airport database. We conducted dwell time analysis using data from Incheon Int'l airport. In order to handle passenger data, we adapted clustering algorithm which is one of data mining techniques. As a clustering result, passengers are divided into 3 clusters. One is the cluster for passengers whose dwell time is relatively short and who tend to spend longer time in the airside. Another is the cluster for passengers who have near 3 hours dwell time. The other is the cluster for passengers whose total dwell time is extremely long.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.12 s.138
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• pp.1644-1654
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• 2004

As globalization has been accelerating in recent years, more people have opportunities to live abroad for an extended period of time, which is known to have strong influence on consumers. The main purposes of this study were to examine if and how sojourning experience could bring changes to people in general and in clothing styles with focus on Korean adults. The researchers conducted in-depth interviews on a total of thirty-six women and twenty-one men who lived in foreign countries more than two years and have been back in Korea longer than one year. The major results indicated that in addition to personalities, age, length of stay, activities during stay, gender, and cultural distances played important roles in bringing long-term changes on people. Re-established self-identity, changes in values, and openness toward diversity were major common changes observed in the interviewees. In addition, they became educated consumers with good knowledge of diverse brands and prices, and emphasized value as opposed to price. Changes in clothing styles were noted mainly among women. They placed high importance on having their own style, coordination and appropriateness, which were consistent with the general changes. Influences of different cultures were also noted.

• Journal of Korean Society of Forest Science
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• v.86 no.1
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• pp.69-79
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• 1997

The purpose of this study is to acquire essential data to reduce the amount of woody debris resulted from the debris flow. This research examined topographic characteristics of the channelbed affecting generation, movement and storage of woody debris and woody characteristics related to number, sizes, shapes, decay, storage direction to mountainous stream. 1. The number of woody debris had a tendency to increase in proportion to stream width, but it was hardly affected by longitudinal gradient of stream. Especially, the greater amount of woody debris was stored at wide section of the stream with compound channel, and it was found in deposits of channelbed rather than in the present channel. 2. Total woody debris over 10cm in diameter and over 2m in length was 402 units and storage number was 35.3 units per 100m of stream. Average diameter of breast height and length were 14cm and 4m, respectively. The woody debris appeared shorter in length and greater in diameter at down-stream than up-stream. 3. Since woody debris met sediments and bed-materials of great roughness in moving, the greater amount of woody debris without root was found in up-stream and down-stream, but deformed woody debris was discovered in upper stream. Decay of woody debris was more severe in down-stream and woody debris on rotting process was found down-stream. 4. Storage direction of woody debris was mainly parallel to center line of stream, and rate of parallel and perpendicularity was 276 and 126 units, respectively. But, as woody debris storing to the perpendicular direction was unstable, the traveling debris could easily be stored. Therefore, some counterplan was required to prevent the traveling woody debris. 5. Tree species of woody debris was mainly larch, which occupied about two third of total woody debris(256 units). The woody debris of larch is easy to move due to hitting of channelbed materials or lower channelbed fluctuation because the lower part of larch is weaker than its upper part. Therefore, the section of the tree species planting in the riparian vegetation needs much more carefulness.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.1-19
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• 2023

Bikes have recently emerged as an alternative to carbon neutrality. To understand the demand for public bikes, we endeavored to estimate travel frequency of public bike by considering the intermediate stops. Using the GPS trajectory data of 'Ttareungyi', a public bike service in Seoul, we identified a stay point and estimated travel frequency reflecting population, land use, and physical characteristics. Application of map matching and a stay point detection algorithm revealed that stay point appeared in about 12.1% of the total trips. Compared to a trip without stay point, the trip with stay point has a longer average travel distance and travel time and a higher occurrence rate during off-peak hours. According to visualization analysis, the stay points are mainly found in parks, leisure facilities, and business facilities. To consider the stay point, the unit of analysis was set as a hexagonal grid rather than the existing rental station base. Travel frequency considering the stay point were analyzed using the Zero-Inflated Negative Binomial (ZINB) model. Results of our analysis revealed that the travel frequency were higher in bike infrastructure where the safety of bike users was secured, such as 'Bikepath' and 'Bike and pedestrian path'. Also, public bikes play a role as first & last mile means of access to public transportation. The measure of travel frequency was also observed to increase in life and employment centers. Considering the results of this analysis, securing safety facilities and space for users should be given priority when planning any additional expansion of bike infrastructure. Moreover, there is a necessity to establish a plan to supply bike infrastructure facilities linked to public transportation, especially the subway.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.77-79
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• 2001

본 연구에서는 전기분해에 의한 양식장 배출수중의 유기물질 및 암모니아를 전류밀도, 전극간격에 따른 제거 특성을 살펴보았다. 전극간격 및 전류밀도에 따른 제거효율은 전극간격이 가까울수록, 전류밀도가 클수록 제거효율은 증가하였다 유기물질은 107.5A/$m^2$의 전류밀도에서 반응기 체류시간 8분동안 98.5%, 암모니아는 전류밀도를 107.15A/$m^2$로 유지하고, 간격을 변화시키면서 반응기 체류시간 120sec동안 암모니아의 제거율을 보면 92.6%의 제거효율을 나타내었다.