• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.143-146
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• 2008

For tracing tag locations, a trajectories should be modeled and indexed in radio frequency identification (RFID) systems. The trajectory of a tag can be represented as a line that connects two spatiotemporal locations captured when the tag enters and leaves the vicinity of a reader. If a tag enters but does not leave a reader, its trajectory is represented only as a point captured at entry and we should extend the region of a query to find the tag that remains in a reader. In this paper, we propose an interval data model of tag's trajectory in order to solve the problem. For the interval data model. we propose a new index scheme called the IR-tree(Interval R-tree) and algorithms of insert and split for processing query efficiently. We also evaluate the performance of the proposed index scheme and compare it with the previous indexes.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.2
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• pp.98-104
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• 2008

In April, July, October and December, 2003, we investigated the effects of water temperature, salinity and extinction coefficient on the distribution of phytoplankton communities at 22 stations in Jinju Bay of Korea. Water temperature and salinity showed a wide range of $10.4^{\circ}C-21.8^{\circ}C$ and 4.34-33.21 psu. Extinction coefficients showed a range of 0.09-3.08, above 1 from almost all the areas except in some central areas, especially, showed highest value (>2) in the estuary area. In phytoplankton, a total of 95 species belonging to 51 genera were identified. The predominant species were mainly diatoms throughout the year. Dominant species was Thalassionema nitzschioides, Skeletonema costatum, Thalassiosira sp. in April, S. costatum, Leptocylindrus danicus in July, C. debilis, S. costatum, C. curvisetus, Pseudonitzshia pungens in October, S. costatum, Asterionellopsis glacialis and C. debilis in December. S. costatum was a major dominant species for all the seasons. Considering the results of literature which is about physiological study, S. costatum seems to be euryhaline and eurythermal, and high affinity on the irradiance. Thus, the species might have been spread population in Jinju Bay where is characteristic of wide range of water temperature, salinity and high extinction coefficients.

• Korean Journal of Remote Sensing
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• v.36 no.3
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• pp.425-439
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• 2020

Through the operations of advanced geostationary meteorological satellite such as Himawari-8 and GK2A, higher resolution and frequency of AOD (Aerosol Optical Depth) data have become available. In this study, we analyzed the characteristics of Himawari-8/AHI (Advanced Himawari Imager) aerosol properties using the recent 4 years (2016~2019) of Sun photometer data observed at the five stations(Seoul National University, Yonsei University, Hankuk University of Foreign Studies, Gwangju Institute of Science and Technology, Anmyon island) which is a part of the AERONET (Aerosol Robotic Network). In addition, we analyzed the causes for the AOD differences between Himawari AOD and Sun photometer AOD. The results showed that the two AOD data are very similar regardless of geographic location, in particular, for the clear condition (cloud amount < 3). However, the quality of Himawari AOD data is heavily degraded compared to that of the clear condition, in terms of bias (0.05 : 0.21), correlation (0.74 : 0.64) and RMSE (Root Mean Square Error; 0.21 : 0.51), when cloud amount is increased. In general, the large differences between two AOD data are mainly related to the cloud amount and relative humidity. The Himawari strongly overestimates the AOD at all five stations when cloud amount and relative humidity are large. However, the wind speed, precipitable water, height of cloud base and Angstrom Exponent have been shown to have no effect on the AOD differences irrespective of geographic location and cloud amount. The results suggest that caution is required when using Himawari AOD data in cloudy conditions.

• Journal of the Korean earth science society
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• v.31 no.4
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• pp.322-334
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• 2010

Spatiotemporal characteristics of precipitation in Korea, associated with the weakening of Tropical Cyclones (TCs) around the Korean Peninsula ($32-36^{\circ}N$, $122-132^{\circ}E$) over the last 30 years (1979-2008), were investigated. Weakened TCs are classified as WEC (Weakened to Extratropical Cyclone) and WTD (Weakened to Tropical Depression). In WEC, precipitation was evenly distributed all over the Korean Peninsula and the greater precipitation was recorded in the southern coast. In WTD, the most precipitation was recorded in the southern coast but low precipitation was recorded in the central and inland areas of Korea. The difference of precipitation between WEC and WTD was not statistically significant in Region 2 (Jeollanam-do, Gyeongsangnam-do, southeastern part of Gyeongsangbuk-do, Jeju-do); however, the precipitation resulting from WEC was greater than that resulting from WTD in Region 1 (central area of Korea, Jeollabuk-do, inland of Gyeongsangbuk-do). In WEC, the developed upper-level potential vorticity (PV) and low-level temperature trough shifted to the northwest of TCs approaching Korea. In addition, an upper-level jet stream and strong divergence field were observed to the northeast of the TCs. It was assumed that these meteorological factors had induced baroclinic instability and diabatic process, which created a large precipitation area around the TCs. However, the intense PV, temperature trough, jet stream were not observed in WTD, which created a small precipitation area around the TCs.

• Journal of Korea Water Resources Association
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• v.53 no.7
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• pp.493-505
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• 2020

The rainfall-runoff model has been generally adopted to obtain a consistent runoff sequence with the use of the long-term ground-gauged based precipitation data. The Thiessen polygon is a commonly applied approach for estimating the mean areal rainfall from the ground-gauged precipitation by assigning weight based on the relative areas delineated by a polygon. However, spatial bias is likely to increase due to a sparse network of the rain gauge. This study aims to generate continuous runoff sequences with the mean areal rainfall obtained from radar rainfall estimates through a PRMS rainfall-runoff model. Here, the systematic error of radar rainfall is corrected by applying the G/R Ratio. The results showed that the estimated runoff using the corrected radar rainfall estimates are largely similar and comparable to that of the Thiessen. More importantly, one can expect that the mean areal rainfall obtained from the radar rainfall estimates are more desirable than that of the ground in terms of representing rainfall patterns in space, which in turn leads to significant improvement in the estimation of runoff.

• (The) Research of the performance art and culture
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• no.18
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• pp.379-412
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• 2009

According to "Jinjak-yigwe(進爵儀軌)", a special banquet was held at Yungyungdang(演慶堂, a kind of royal theatre) to celebrate the 40th birthday of Queen Soonwon(純元王后) in 1828. This banquet is famous for the presentation of nineteen new Jungjae(呈才) repertoires that the Crown Prince Hyomyung(孝明) created. In order to explore the theoretical basis for the reproduction and presentation of Yungyungdang(演慶堂) Jinjak(進爵, a type of royal banquets), in this article, the imagination and experience of the presentation of Yungyungdang Jinjak are pursued, while focussing on audience's reception. In Yungyungdang Jinjak, King Soonjo(純祖), Queen Soonwon and the prince were the special audience; they participated in the procedure of Ye(禮, etiquette of ceremony) and also were considered as the characters of certain repertoire of Jungjae. Hyomyung arranged the spectacles from the myths of Taoist gods and immortal hermits, as well as historic episodes of the past emperors' elegant tastes of music. These mythic and historic images lead the audience toward the imagination and experience on the transcendental world. Hyomyung, managing the administration as the representative of King Soonjo, tried to show absolute royal authority through the splendid performances of Yungyungdang Jinjak, so as to overcome the politicaly difficult situation. He set up the sacred world for his father King Soonjo, distinct from the secular ordinary world, and emphasized his position as the bridge between the two sides. He expressed his filial duty through the devotion of performing arts to display absolute royal authority.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.100-100
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• 2017

하천에 유입된 오염물질의 2차원 혼합거동은 하천 주흐름에 의한 이송현상과 유속 성분의 수심평균 값에 대한 공간적 편차로부터 야기되는 분산현상으로 설명 할 수 있다. 이는 3차원 이송확산 방정식으로부터 수심 적분된 2차원 이송-분산 방정식으로 수학적 유도가 가능하며, 수심방향으로 적분하는 과정에서 발생되는 농도의 분산항은 Taylor Dispersion 개념에 기초하여 종방향 및 횡방향의 2차원 분산계수로 표현된다. Fischer(1978)는 연직방향 유속분포로부터 2차원 분산계수를 추정하는 해석해를 수학적으로 유도하였으나, 실제 하천에서 정밀한 연직방향 유속분포를 계측하는 것은 많은 비용 및 노동력을 초래한다. 따라서 선행 연구자들은 2차원 혼합모형의 분산계수를 산정하고자 실험적 방법으로써 추적자실험을 수행하였다. 추적자실험은 추적자 물질을 수체에 주입한 후 농도의 변화를 관측함으로써 추적자물질이 하천에서 이송 및 분산되는 과정을 이해하는데 유용하다. 기존의 추적자실험은 고정된 위치에서 농도를 계측하여 시계열적인 농도의 변화를 관측한 후, 오염운 동결가정을 통해 종,횡방향 분산계수의 산정이 가능하지만, 오염물질 농도의 공간적 분포를 얻기에는 한계가 있다. 본 연구에서는 기존의 추적자실험법의 한계를 극복하고자 형광물질을 이용한 추적자실험을 수행함과 동시에 드론에 장착된 디지털카메라를 이용하여 항공영상을 취득 및 분석하여, 하천에 주입된 형광물질의 농도분포를 시공간적으로 추출하는 기법을 개발하고, 이를 바탕으로 오염물질의 2차원 혼합거동을 분석하였다. 본 실험은 한국건설기술연구원의 안동하천실험센터의 A3실험수로에서 수행되었으며, 실험수로는 평균 하폭 5 m, 평균 수심 0.44 m, 유량 $0.96m^3/s$의 실제 소규모 하천과 유사한 축척을 가지고 있다. 추적자물질은 Rhodamine WT 용액이 사용되었으며, 실험수로 내 설치된 15개의 형광광도계(YSI-600OMS)를 이용하여 농도를 측정하였다. 항공영상의 취득을 위해 이용된 드론은 DJI-Phantom 3 Professional 이며, 3840x2160의 해상도로 초당 30 frame의 동영상으로 취득되었다. 영상의 정합 및 좌표화를 위해 RTK-GPS를 이용하여 12개의 지상 기준점의 좌표를 취득한 후, 사영변환을 통해 영상좌표를 지상좌표로 변환하였다. 영상의 픽셀값을 농도장으로 변환하기 위해 각 RGB 밴드의 픽셀값을 통계적으로 분석하여 농도장으로 변환하였으며, 영상으로부터 얻은 농도장은 형광광도계에 의해 실측된 농도와 결정계수 0.9이상의 수준으로 정확도를 나타냈다.

• Korean Journal of Remote Sensing
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• v.23 no.6
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• pp.507-520
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• 2007

Satellite passive microwave(PM) sensors have been observing polar sea ice concentration(SIC), ice temperature, and snow depth since 1970s. Among them SIC is playing an important role in the various studies as it is considered the first factor for the monitoring of global climate and environment changes. Verification and correction of PM SIC is essential for this purpose. In this study, we calculated SIC from KOMPSAT-1 EOC images obtained from Arctic sea ice edges from July to August 2005 and compared with SSM/I SIC calculated from NASA Team(NT) algorithm. When we have no consideration of sea ice types, EOC and SSM/I NT SIC showed low correlation coefficient of 0.574. This is because there are differences in spatial resolution and observing time between two sensors, and the temporal and spatial variation of sea ice was high in summer Arctic ice edge. For the verification of SSM/I NT SIC according to sea ice types, we divided sea ice into land-fast ice, pack ice, and drift ice from EOC images, and compared them with SSM/I NT SIC corresponding to each ice type. The concentration of land-fast ice between EOC and SSM/I SIC were calculated very similarly to each other with the mean difference of 0.38%. This is because the temporal and spatial variation of land-fast ice is small, and the snow condition on the ice surface is relatively dry. In case of pack ice, there were lots of ice ridge and new ice that are known to be underestimated by NT algorithm. SSM/I NT SIC were lower than EOC SIC by 19.63% in average. In drift ice, SSM/I NT SIC showed 20.17% higher than EOC SIC in average. The sea ice with high concentration could be included inside the wide IFOV of SSM/I because the drift ice was located near the edge of pack ice. It is also suggested that SSM/I NT SIC overestimated the drift ice covered by wet snow.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.6
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• pp.96-105
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• 2010

This study identified the dynamic process of sandbar and vegetation distribution of the sandbar on the Tan-cheon River. The study area is located in the lower reaches of the Tan-cheon River that has been managed as an Ecosystem Reserve Area since 2002. For the study, the geomorphological process was analyzed through mapping analysis using a satellite image followed by analysis of the vegetation distribution through an on-site survey. The major findings were as follows : First, In the fluvial geomorphic process, various kinds of sandbars were developed in 1990s, the morphologic characteristics changing continuously. Second, In the distribution of vegetation on the sandbar, the sandbar shore was covered with bare sand substrate or intermittent annual vegetation because of the periodic fluctuation of the water-level due to intensive disturbances. Third, In the relationship between the sandbar formation and vegetation, four types of sandbars were classified: channel-shore stable bar, channel-shore unstable bar, mid-channel stable bar and mid-channel unstable bar, according to the fluvial disturbance & vegetation process. The study verifies that the vegetation distribution is reciprocally related to the geomorphological process. Accordingly, it is meaningful in the selection of plant species and the planting area of the sand bar. However, it is limited to the planting guidelines on river restoration projects. More diverse on-site experimental studies should be conducted.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.99-105
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• 2014

Since traffic accidents account for the highest proportion of the artificial disasters which occur in urban areas along with fire, more scientific an analysis on the causes of traffic accidents and various prevention measures against traffic accidents are needed. In this study, the research selected Jinju-si, which belongs to local small and medium-sized cities as a research target to analyze the characteristics of temporal and spacial distribution of traffic accidents by associating the data of traffic accidents, occurred in 2013 with the causes of traffic accidents and location information that includes occurrence time and seasonal features. It subsequently examines the spatial correlation between traffic accidents and the characteristics of urban space development according to the plans of land using. As a result, the characteristics of accident distribution according to the types of accidents reveal that side right-angle collisions (car versus car) and pedestrian-crossing accident (car versus man) showed the highest clustering in the density analysis and average nearest neighbor analysis. In particular, traffic accidents occurred the most on roads which connect urban central commercial areas, high-density residential areas, and industrial areas. In addition, human damage in damage conditions, clear day in weather condition, dry condition in the road condition, and three-way intersection in the road way showed the highest clustering.