• Journal of Astronomy and Space Sciences
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• 제35권3호
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• pp.185-193
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• 2018

Jang Bogo Station (JBS), the second Korean Antarctic research station, was established in Terra Nova Bay, Antarctica ($74.62^{\circ}S$ $164.22^{\circ}E$) in February 2014 in order to expand the Korea Polar Research Institute (KOPRI) research capabilities. One of the main research areas at JBS is space environmental research. The goal of the research is to better understand the general characteristics of the polar region ionosphere and thermosphere and their responses to solar wind and the magnetosphere. Ground-based observations at JBS for upper atmospheric wind and temperature measurements using the Fabry-Perot Interferometer (FPI) began in March 2014. Ionospheric radar (VIPIR) measurements have been collected since 2015 to monitor the state of the polar ionosphere for electron density height profiles, horizontal density gradients, and ion drifts. To investigate the magnetosphere and geomagnetic field variations, a search-coil magnetometer and vector magnetometer were installed in 2017 and 2018, respectively. Since JBS is positioned in an ideal location for auroral observations, we installed an auroral all-sky imager with a color sensor in January 2018 to study substorms as well as auroras. In addition to these observations, we are also operating a proton auroral imager, airglow imager, global positioning system total electron content (GPS TEC)/scintillation monitor, and neutron monitor in collaboration with other institutes. In this article, we briefly introduce the observational activities performed at JBS and the preliminary results of these observations.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제23권7호
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• pp.786-792
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• 2019

Currently, various kinds of contents using smart phone's location information are developed and provided to users. The market size of the location-based service industry utilizing location information is also increasing every year and the majority of smart phone users occupy university students and most of the university students are using their owns smart phones, and they are the biggest users of location-based services and the main target of location information collection. In this paper, we conduct to a survey how university students understand about location information. Based on the results of the survey, we will deeply examine which one is needed to improve understanding of university students' location information collection and usage and what should be considered for the development of the location-based service industry and education of location information and then we propose some helpful suggestion.

• Korean Journal of Remote Sensing
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• 제34권6_2호
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• pp.1165-1178
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• 2018

Collapse of an Antarctic ice shelf and its flow velocity changes has the potential to reduce the restraining stress to the seaward flow of the Antarctic Ice Sheet, which can cause sea level rising. In this study, variations in ice velocity from 2000 to 2017 for the Nansen Ice Shelf in East Antarctica that experienced a large-scale collapse in April 2016 were analyzed using Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-8 Operational Land Imager (OLI) images. To extract ice velocity, image matching based on orientation correlation was applied to the image pairs of blue, green, red, near-infrared, panchromatic, and the first principal component image of the Landsat multispectral data, from which the results were combined. The Landsat multispectral image matching produced reliable ice velocities for at least 14% wider area on the Nansen Ice Shelf than for the case of using single band (i.e., panchromatic) image matching. The ice velocities derived from the Landsat multispectral image matching have the error of $2.1m\;a^{-1}$ compared to the in situ Global Positioning System (GPS) observation data. The region adjacent to the Drygalski Ice Tongue showed the fastest increase in ice velocity between 2000 and 2017. The ice velocity along the central flow line of the Nansen Ice Shelf was stable before 2010 (${\sim}228m\;a^{-1}$). In 2011-2012, when a rift began to develop near the ice front, the ice flow was accelerated (${\sim}255m\;a^{-1}$) but the velocity was only about 11% faster than 2010. Since 2014, the massive rift had been fully developed, and the ice velocity of the upper region of the rift slightly decreased (${\sim}225m\;a^{-1}$) and stabilized. This means that the development of the rift and the resulting collapse of the ice front had little effect on the ice velocity of the Nansen Ice Shelf.

• Journal of Veterinary Clinics
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• 제33권5호
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• pp.278-285
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• 2016

Epidemiological studies have shown the association between transportation of live animals and the potential transmission of infectious disease between premises. This finding was also observed in the 2014-2015 foot-and-mouth disease (FMD) outbreak in Korea. Furthermore, slaughterhouses played a key role in the global spread of the FMD virus during the epidemic. In this context, in-depth knowledge of the structure of direct and indirect contact between slaughterhouses is paramount for understanding the dynamics of FMD transmission. But the social network structure of vehicle movements to slaughterhouses in Korea remains unclear. Hence, the aim of this study was to configure a social network topology of vehicle movements between slaughterhouses for a better understanding of how they are potentially connected, and to explore whether FMD outbreaks can be explained by the network properties constructed in the study. We created five monthly directed networks based on the frequency and chronology of on- and off-slaughterhouse vehicle movements. For the monthly network, a node represented a slaughterhouse, and an edge (or link) denoted vehicle movement between two slaughterhouses. Movement data were retrieved from the national Korean Animal Health Integrated System (KAHIS) database, which tracks the routes of individual vehicle movements using a global positioning system (GPS). Electronic registration of livestock movements has been a mandatory requirement since 2013 to ensure traceability of such movements. For each of the five studied networks, the network structures were characterized by small-world properties, with a short mean distance, a high clustering coefficient, and a short diameter. In addition, a strongly connected component was observed in each of the created networks, and this giant component included 94.4% to 100% of all network nodes. The characteristic hub-and-spoke type of structure was not identified. Such a structural vulnerability in the network suggests that once an infectious disease (such as FMD) is introduced in a random slaughterhouse within the cohesive component, it can spread to every other slaughterhouse in the component. From an epidemiological perspective, for disease management, empirically derived small-world networks could inform decision-makers on the higher potential for a large FMD epidemic within the livestock industry, and could provide insights into the rapid-transmission dynamics of the disease across long distances, despite a standstill of animal movements during the epidemic, given a single incursion of infection in any slaughterhouse in the country.

• KOREAN JOURNAL OF CROP SCIENCE
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• 제54권2호
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• pp.192-197
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• 2009

This study was conducted to investigate the effect of site-specific variable fertilization following digital fertility map generated from soil analysis on rice growth and yield. The site-specific application of fertilizer was implemented by using rice transplanter equipped with side dressing applicator and global positioning system (GPS). Coefficient of variation (C.V.) of soil nitrogen content was reduced after the experiment, and spatial variation of semivariogram was reduced. Rice growth from tillering to ripening stage, plant height, tiller and panicle number increased at site-specific variable fertilization treatment, and coefficient variation (C.V.) of each growth characteristics was lower than those of conventional fertilization treatment. As a result, fertility in the rice field was more uniform become of site-specific fertilizer application. Head rice yield of site-specific application plot increased by 9% (i.e., to from 450 kg/10a to 492 kg/10a of the control plot) and its CV was significantly reduced to 3.5 compared to 7.8 of the control plot. In addition, there was no significant difference in amylose, protein contents and whiteness of milled rice, but its CV was reduced.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• 제33권2호
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• pp.83-94
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• 2015

Recently, the necessity of spatial data in unaccessible area was challenged to set up various plans and policies for preparing the unification and the cooperative projects between South-North Korea. Therefore, this paper planned to evaluate the possibility of adopting the error tolerance in Geometric correction for 1/5,000 digital topographic mapping, using the PLEIADES images and the TerraSAR GCPs (Ground Control Points). The geometric correction was performed by changing the number and placement of GCPs by GPS (Global Positioning System) surveying, as the optimal placement of 5 GCPs were selected considering the geometric stability and steady rate. The positional accuracy evaluated by the TerraSAR GCPs, which were selected by optimal placement of GCPs. The RMSE in control points were X=±0.64m, Y=±0.46m, Z=±0.28m. While the result of geometric correction for PLEIADES images confirmed that the RMSE in control points were X=±0.34m, Y=±0.27m, Z=±0.11m, the RMSE in check points were X=±0.50m, Y=±0.30m, Z=±0.66m. Through this study, we believe if spatial data can integrate with the PLEIADES images and the optimal TerraSAR GCPs, it will be able to obtain the high-precision spatial data for adopting the regulation of 1/5,000 digital topographic map, which adjusts the computation as well as the error bound.

• Journal of the Korean earth science society
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• 제26권7호
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• pp.691-697
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• 2005

Recently, the development of accurate gravity-meter and GPS make it possible to obtain high resolution gravity data. Though gravity data interpretation like modeling and inversion has significantly improved, gravity data processing itself has improved very little. Conventional gravity data processing removes gravity effects due to mass and height difference between base and measurement level. But, it would be a biased density model when some or whole part of anomalous bodies exist above the base level. We attempted to make a multiquadric surface of the survey area from topography with DEM (Digital Elevation Map) data. Then we constituted rectangular blocks which reflect real topography of the survey area by the multiquadric surface. Thus, we were able to carry out 3-D inversions which include information of topography. We named this technique, 3-D Gravity Terrain Inversion (3DGTI). The model test showed that the inversion model from 3DGTI made better results than conventional methods. Furthermore, the 3-dimensional model from the 3DGTI method could maintain topography and as a result, it showed more realistic geologic model. This method was also applied on real field data in Masan-Changwon area. Granitic intrusion is an important geologic characteristic in this area. This method showed more critical geological boundaries than other conventional methods. Therefore, we concluded that in the case of various rocks and rugged terrain, this new method will make better model than convention ones.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제19권5호
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• pp.70-81
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• 2020

Point-by-point data, which is abundantly collected by vehicles with embedded GPS (Global Positioning System), generate useful information. These data facilitate decisions by transportation jurisdictions, and private vendors can monitor and investigate micro-scale driver behavior, traffic flow, and roadway movements. The information is applied to develop app-based route guidance and business models. Of these, speed data play a vital role in developing key parameters and applying agent-based information and services. Nevertheless, link speed values require different levels of physical storage and fidelity, depending on both collecting and reporting intervals. Given these circumstances, this study aimed to establish an appropriate collection interval to efficiently utilize Space Mean Speed information by vehicles with embedded GPS. We conducted a comparison of Probe-vehicle data and Image-based vehicle data to understand PE(Percentage Error). According to the study results, the PE of the Probe-vehicle data showed a 95% confidence level within an 8-second interval, which was chosen as the appropriate collection interval for Probe-vehicle data. It is our hope that the developed guidelines facilitate C-ITS, and autonomous driving service providers will use more reliable Space Mean Speed data to develop better related C-ITS and autonomous driving services.

• Journal of the Korean Association of Geographic Information Studies
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• 제15권1호
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• pp.197-210
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• 2012

The KOrea Multi-Purpose SATellite(KOMPSAT)-2 has a capability to provide a cross-track stereo imagery using two different orbits for generating various spatial information. However, in order to fully realize the potential of the KOMPSAT-2 stereo imagery in terms of mapping, various tests are necessary. The purpose of this study is to evaluate the possibility of mapping using the KOMPSAT-2 stereo imagery. For this, digital plotting was conducted based on the stereoscopic images. Also the Digital Elevation Model(DEM) and an ortho-image were generated using digital plotting results. An accuracy of digital plotting, DEM, and ortho-image were evaluated by comparing with the existing data. Consequently, we found that horizontal and vertical error of the modeling results based on the Rational Polynomial Coefficient(RPC) was less than 1.5 meters compared with the Global Positioning System(GPS) survey results. The maximum difference of vertical direction between the plotted results in this study and the existing digital map on the scale of 1/5,000 was more than 5 meters according as the topographical characteristics. Although there were some irregular parallax on the images, we realized that it was possible to interpret and plot at least seventy percent of the layer which was required the digital map on the scale of 1/5,000. Also an accuracy of DEM, which was generated based on the digital plotting, was compared with the existing LiDAR DEM. We found that the ortho-images, which were generated using the extracted DEM in this study, sufficiently satisfied with the requirement of the geometric accuracy for an ortho-image map on the scale of 1/5,000.

• Proceedings of the Korea Water Resources Association Conference
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• 한국수자원학회 2012년도 학술발표회
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• pp.691-695
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• 2012

수위표의 영점에서 수면까지의 높이로 정의되는 해발수위는 유량 및 유사량 등과 같은 관련 수문자료를 생산하는데 기본이 되는 자료이며, 하천 및 수공구조물의 설계 등에 기초자료로 이용될 뿐만 아니라 수자원의 효율적인 관리 및 수문순환 해석을 위한 가장 중요한 기초자료로서 국가 차원의 올바른 수자원 계획과 정책을 수립하는데 널리 활용된다. 이와 같이 해발수위자료의 이용 분야가 다양하고 그 자체로서도 중요한 의미를 가지는 점을 고려할 때 무엇보다도 중요한 것은 자료의 품질이 확보되어야 하는 것이다. 그러나 영점표고검정수준점 및 기준 수위표의 설치 이후 오랜 시간이 경과됨에 따라 노후화와 수위관측소 주변의 환경변화가 발생하게 되어 자료의 정확도가 매우 낮아지고 있다. 본 연구에서는 해발수위 자료의 품질향상을 위해 수위관측소의 영점표고검정수준점 및 수위표 영점표고에 대하여 수준측량 및 RTK(Real Time Kinematic) GPS(Global Positioning System) 측량을 병행하여 수행하였으며, 조사측량된 값을 활용하여 기존에 측량된 영점표고검정수준점 및 수위표 영점표고에 대한 검토를 수행하였다. 금강 및 삽교천 수계에 위치한 50개 수위관측소 대하여 기존 측량값과 비교 검토한 결과 영점표고검정수준점은 0.10m 이하(54.0%), 0.10m 초과 ~ 0.50m 이하(26.0%), 0.50m 초과 ~ 1.00m 이하(6.0%), 1.00m초과 ~ 1.50m 이하(2.0%), 1.50m 초과 ~ 2.00m 이하(2.0%), 2.00m 초과 ~ 3.00m 이하(4.0%), 3.00m 초과(6.0%)의 값을 나타냈으며, 수위표 영점표고는 0.10m 이하(50.0%), 0.10m 초과 ~ 0.50m 이하(32.0%), 0.50m 초과 ~ 1.00m 이하(10.0%), 1.00m초과 ~ 1.50m 이하(2.0%), 1.50m 초과 ~ 2.00m 이하(2.0%), 2.00m 초과 ~ 3.00m 이하(2.0%), 3.00m 초과(2.0%)의 값을 가졌다. 이와 같이 기존과 금회 측량자료를 비교 검토한 결과 대부분이 안정적으로 유지되고 있으나 일부 수위관측소에서 변동량이 크게 발생한 원인은 영점표고검정수준점의 노후화, 기준 수위표의 교체 및 위치 변동, 인위적인 하천공사 등으로 인하여 발생한 것으로 판단된다.