• Journal of Korean Society for Geospatial Information Science
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• v.25 no.2
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• pp.31-37
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• 2017

Recently, governmental authority and local government are looking for a method of utilizing location information of smart phone for urgent rescue in fire and kidnap situation. Under this background, in this study, a method of rapidly collecting, constructing location determination based Wi-Fi AP data utilizing location information of smart phone and mobile mapping system was suggested in order to construct precise positioning information that could be utilized under urgent situation. By performing compensation work for GPS/INS/DMI through collected outcome, position of collected vehicle was acquired. In addition, source data integrating Wi-Fi information and collected position by coupling based on Wi-Fi AP collector and GPS time was constructed and Wi-Fi radiomap was constructed by removing Wi-Fi signal noise that reduces precise position performance. As a result of performing location determination performance assess ment by selecting 10 test positions by each local government, result value of 25.46cm for total local government average and 27.76m for SD could be obtained. It is considered that this result could be utilized as a technology of being able to supplement or substituting GPS location determination technology that is impossible in plocation determination of mobile communication company's base station (200m~2km) and indoor being used at present.

• Korean Journal of Environment and Ecology
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• v.29 no.3
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• pp.441-453
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• 2015

In this paper, according to the illuminance at night with artificial lighting in downtown Seoul, trees flowering and leaf growth rate was performed as a case study to examine whether there is a difference. The illuminance was measured at 78 points on a total of 26 points, the range of illuminance were divided into three groups considering land use, Group A (plots 1-7) were 4.90 ~ 112.50 lx, Group B (plots 8 to 18) were 0.45 ~ 42.40 lx, group C (plots 19 to 26) were 0.28 ~ 22.10 lx. According to the One-way ANOVA on illuminance difference, the survey groups were classified into three groups. To survey the ratio of the flowering Prunus yedoensis and Rhododendron spp. and to survey the ratio of leaf growth Zelkova serrata, Ginkgo biloba, and Acer palmatum each 30 individuals were investigated. Rhododendron spp. to study the ratio of the flowering and Acer palmatum to study the ratio of leaf growth were determined to be useful as indicator woody species according to the correlation. The higher illuminance of night lighting is, the faster flowering and leaf growth of trees will be by correlation between the mean illuminance of each group and the flowering and leaf growth of trees. In the future, should be made a more detailed study of how much affect to the trees with some impact on the level of light pollution at night lighting.

• Spatial Information Research
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• v.22 no.5
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• pp.65-75
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• 2014

Bus headway plays an important role not only in determining the passenger waiting time and bus service quality, but also in influencing the bus operation cost and passenger demand. Previous research on headway control has considered only an hourly difference in the distribution of ridership between peak and non-peak hours. However, this approach is too simple to help manage ridership demand fluctuations in a short time scale; thus passengers' waiting cost will be generated when ridership demand exceeds the supply of bus services. Moreover, bus ridership demand varies by station location and traffic situation. To address this concern, we propose a headway control algorithm for minimizing the waiting time cost by using Smart Card data. We also provide proof of the convergence of the algorithm to the desired headway allocation using a set of preconditions of political waiting time guarantees and available fleet constraints. For model verification, the data from the No. 143 bus line in Seoul were used. The results show that the total savings in cost totaled approximately 600,000 won per day when we apply the time-value cost of waiting time. Thus, we can expect that cost savings will be more pronounced when the algorithm is applied to larger systems.

• Journal of Korea Water Resources Association
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• v.49 no.9
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• pp.799-807
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• 2016

The aim of this study is to determine and propose the by-pass rainwater sewer system in order to reduce the urban floodplain from the locality heavy rain every year during the dry season and the sinkholes in the city as well as the shortage of groundwaters due to extreme hot weather condition and urban heat island phenomenon. Heavy rain occurs more than the years of heavy rainfall probability, comparison between the place where uses the existing pipes and connect the sewer system with by-pass rain permeability and without expanding sewer pipe replacement at intersection of Gangnam station 3.07 ha at Gangnam-gu, Seoul Metropolitan area, it indicates that average of 27 million KRW (44%) maintenance cost savings and maintain existing sewer system without any other countermeasures. For the city flooded reduction, by-pass rainwater permeable rainwater pipe multiplying the probability the number of years during summer season and increase the water flow capacity during spring and fall when a small amount of rain that, it also contribute to the total amount of underground water secured through the by-pass penetration.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.253-263
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• 2016

Chrysanthemum production would benefit from crop growth simulations, which would support decision-making in crop management. Chrysanthemum is a typical short day plant of which floral initiation and development is sensitive to photoperiod. We developed a model to predict phenological development and leaf appearance of chrysanthemum (cv. Baekseon) using daylength (including civil twilight period), air temperature, and management options like light interruption and ethylene treatment as predictor variables. Chrysanthemum development stage (DVS) was divided into juvenile (DVS=1.0), juvenile to budding (DVS=1.33), and budding to flowering (DVS=2.0) phases for which different strategies and variables were used to predict the development toward the end of each phenophase. The juvenile phase was assumed to be completed at a certain leaf number which was estimated as 15.5 and increased by ethylene application to the mother plant before cutting and the transplanted plant after cutting. After juvenile phase, development rate (DVR) before budding and flowering were calculated from temperature and day length response functions, and budding and flowering were completed when the integrated DVR reached 1.33 and 2.0, respectively. In addition the model assumed that leaf appearance terminates just before budding. This model predicted budding date, flowering date, and leaf appearance with acceptable accuracy and precision not only for the calibration data set but also for the validation data set which are independent of the calibration data set.

• Economic and Environmental Geology
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• v.31 no.3
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• pp.215-222
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• 1998

The radon (Rn-222) potential of metropolitan subway stations and soils in Seoul city were delineated using alpha-track filter and EDA-200 radon detectors, respectively. The uranium (U) and thorium (Th) contents were also determined using a Multi Channel Analyzer to identify the sources of radon gas. The average U concentrations in Seoul varies according to basement rock types. For example, there is $9.40{\pm}10.11ppm$ in the Precambrian metasedimentary rock (PM), $9.08{\pm}2.85ppm$ in the Jurassic Kwanaksan granite (JK) and $4.94{\pm}1.43ppm$ in the Jurassic Seoul granite (JS). Uranium contents in soil samples are $10.30{\pm}4.74ppm$ in JK, $10.10{\pm}7.43ppm$ in PM and $6.69{\pm}3.95ppm$ in JS and these closely reflect the content of uraniferous minerals. The levels of soil radon are $604{\pm}273pCi/L$ in JK, $502{\pm}275$ in JS and $262{\pm}211pCi/L$ in PM. The soil radon concentrations are shown to reflect soil permeability and porosity rather than their U contents. The mean indoor radon contents in subway stations are $1.50{\pm}0.62pCi/L$ on the 4th line, $1.41{\pm}0.95pCi/L$ on the 3rd line, $0.84{\pm}0.13pCi/L$ on the 1st line and $0.80{\pm}0.25pCi/L$ on the 2nd line. The subway stations located in the JK have the highest average radon concentration with $2.04{\pm}0.65pCi/L$, where levels of $1.57{\pm}0.81pCi/L$ occur in the JS and $0.80{\pm}0.23pCi/L$ in the PM. The highest radon levels of 4.1 pCi/L occur mainly in Keongbokkung station on the 3rd line and these exceed 4 pCi/L of the US EPA action level.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.737-744
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• 2016

Seoul Metropolitan Area has been changed by fierce internal migration during the last several decades. To determine the regional structure, we analyzed the in-and-out migration pattern and main factors affecting the intense of mobility. The migration within metropolitan city and province shows that in Seoul, Songpa and Dobong Gu gained a large population, in Incheon, Namdong Gu experienced a huge population influx, and in Gyeonggi Province, Hwasung, Yongin and Paju city gained a great population. In Seongnam, Suwon city lost a lot of population. These population gains and losses came from mainly residential redevelopment projects in the metropolitan city and new land development projects in Gyeonggi Province. The main factors affecting the intense of mobility diverse from city characters. In central type cities, house price gets the more population influx. In job-housing balanced cities, total income growth rate, housing supply rate and roads cause in-migration. In bed-town type cities, the increase of housing supply rate and parks increase the population. In suburban type cities, business density, housing supply rate, housing, subway station number and educational facilities increase population from outside the city. So, we have to prepare more detailed urban and housing policy responses.

• Journal of Cadastre & Land InformatiX
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• v.49 no.1
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• pp.157-179
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• 2019

The Seoul's 2030 Youth-Housing has been regarded as the only option to procure rental housing sites in downtown Seoul. But its supply did not catch up with the initial expectation, and the criticism that it may disrupt the current zoning system of the city has persisted. Consequently, the 2030 Youth-Housing policy has undergone amendments for six times within the last three years, and the significant changes in its guideline also have been made within the last one year. The study, in this context, tries to figure out the tendencies of those changes made in the guidelines so far by analyzing the aspects of the parcels allowable for Youth-Housing as well as the areas allowable for up-zoning. In the process, the propositional logic is to be adopted to draw the scope of the buildable areas for Youth-Housing. For this, the study refines the raw GIS data, inputs the values for each proposition, and proceeds the logical operation to judge every parcel of the city to discern whether it is eligible for a buildable site and/or for up-zoning for Youth-Housing. It is seen that: 1) the buildable sites rather evenly distribute around the peripheral subway-station areas while more concentrating on the quasi-residential and commercial areas; and 2) the areas eligible for up-zoning have the tendency to concentrate more on quasi-residential areas than others.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.6
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• pp.48-57
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• 2020

This study was aimed to determine the history of Son keechung laurel tree, which is designated and managed as Seoul Metropolitan Government Monument No. 5. Sohn keechung's victory in the marathon at the 1936 Berlin Olympics served as an opportunity to encourage great pride and national spirit for the Korean people's national spirit who had spent their painful days under Japanese colonial rule. The seedlings that Son keechung received at the time are currently growing at Son Keechung Sports Park on the hill in Manri-dong, west of Seoul Station, and are Quercus palustris. That variety of Tree is native to the United States. The 11th Berlin Olympics, held in 1936, is a golden opportunity for Hitler to show off the history and cultural excellence of the German race, so it does not make sense to award victors an American giant oak instead of the German oak tree. The Seoul Metropolitan Government and various media outlets made a fait accompli due to Hitler's simple mistake. However, this study revealed that the laurel that Son received was the Quercus robur, based on the articles of the Korean newspaper, the German daily newspaper, and the recently introduced article of Der Spiegel, a leading German weekly magazine. Based on these circumstances, I would like to suggest that the originally awarded Quercus robur be planted in Son keechung Memorial Park and that the newly discovered history be notified on the Seoul Metropolitan Government website and various records.

• Information Systems Review
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• v.22 no.1
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• pp.147-165
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• 2020

The sharing economy service is now spreading in various fields such as accommodation, cars and bicycles. In particular, bicycle-sharing service have become very popular around the world, and since September 2015, Seoul has been providing a bicycle-sharing service called 'Ttareungi'. However, the number of bicycles is unbalanced among rental stations continuously according to the user's bicycle use. In order to solve these problems, we employed social network analysis using Ttareungi data in Seoul, Korea. We analyzed degree centrality, closeness centrality, betweenness centrality and k-core. As a result, the degree centrality was found to be closely linked with bus or subway transfer center. Closeness centrality was found to be in an unbalanced departure and arrival frequency or poor public transport proximity. Betweenness centrality means where the frequency of departure and arrival occurs frequently. Finally, the k-core analysis showed that Mapo-gu was the most important group by time zone. Therefore, the results of this study may contribute to the planning of relocation and additional installation of bike rental station in Seoul.