• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1869-1880
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• 2021

Korean Journal of Remote Sensing (KJRS), leading the field of remote sensing and GIS in South Korea for over 37 years, has published interdisciplinary research papers. In this study, we performed the topic modeling based on Latent Dirichlet Allocation (LDA), a probabilistic generative model, to identify the research topics and trends using 1) the whole articles, and 2) specific articles related to natural and environmental disasters published in KJRS by analyzing titles, keywords, and abstracts. The results of LDA showed that 4 topics('Polar', 'Hydrosphere', 'Geosphere', and 'Atmosphere') were identified in the whole articles and the topic of 'Polar' was dominant among them (linear slope=3.51 × 10^-3, p<0.05) over time. For the specific articles related to natural and environmental disasters, the optimal number of topics were 7 ('Marine pollution', 'Air pollution', 'Volcano', 'Wildfire', 'Flood', 'Drought', and 'Heavy rain') and the topic of 'Air pollution' was dominant (linear slope=2.61 × 10^-3, p<0.05) over time. The results from this study provide the history and insight into natural and environmental disasters in KRJS with multidisciplinary researchers.

• Economic and Environmental Geology
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• v.54 no.3
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• pp.353-364
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• 2021

Since the mid-twentieth century, geology has gradually evolved as an interdisciplinary context in South Korea. The journal of Economic and Environmental Geology (EEG) has a long history of over 52 years and published interdisciplinary articles based on geology. In this study, we performed a literature review using topic modeling based on Latent Dirichlet Allocation (LDA), an unsupervised machine learning model, to identify geological topics, historical trends (classic topics and emerging topics), and association by analyzing titles, keywords, and abstracts of 2,571 publications in EEG during 1968-2020. The results showed that 8 topics ('petrology and geochemistry', 'hydrology and hydrogeology', 'economic geology', 'volcanology', 'soil contaminant and remediation', 'general and structural geology', 'geophysics and geophysical exploration', and 'clay mineral') were identified in the EEG. Before 1994, classic topics ('economic geology', 'volcanology', and 'general and structure geology') were dominant research trends. After 1994, emerging topics ('hydrology and hydrogeology', 'soil contaminant and remediation', 'clay mineral') have arisen, and its portion has gradually increased. The result of association analysis showed that EEG tends to be more comprehensive based on 'economic geology'. Our results provide understanding of how geological research topics branch out and merge with other fields using a useful literature review tool for geological research in South Korea.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.627-642
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• 2022

The world's long reliance on fossil fuels (e.g., oil, coal, and natural gas) is severely changing its environment and climate. Energy research has focused on developing hydrogen as the most promising energy carrier and a key technology for sustainable energy development. Hydrogen can be classified as gray, blue, green, and otherwise according to the raw materials and methods used for production and processing. For the development of hydrogen energy, geologists are attempting to identify the mechanism of abiotic hydrogen generation by serpentinization or hydrothermal alteration. Teams in the United States, France, and Australia have researched laboratory-scale hydrogen production through water-rock interactions under various conditions, whereas there has been almost no research on abiotic hydrogen in South Korea. This paper reviews the current state of international research on hydrothermal alteration and offers suggestions for future investigations of abiotic hydrogen production in South Korea.

• Journal of Satellite, Information and Communications
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• v.8 no.3
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• pp.41-46
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• 2013

In this paper, we present the compatibility study results including the frequency sharing criteria between new allocation to maritime mobile satellite service and Earth exploration satellite service in the 7/8 GHz. The transmitting Earths station of MMSS in the 8025 - 8400 MHz band would make harmful interference to the receiving Earth station of EESS operating in the same frequency band. In order to ensure the compatibility with EESS, the separation distance is provided as a frequency sharing criteria. The republic of Korea has a plan to launch the geostationary satellite around 2017 and EESS Earth station will be operated in 8025 - 8400 MHz band. Therefore, we calculate the interference levels and separation distance using the system parameters of two Earth station systems. As results of the study, the separation distances for LOS path and Non-LOS path due to the geographical characteristics are shown around 471 km and 200 km, respectively.

• Spatial Information Research
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• v.19 no.6
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• pp.101-109
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• 2011

Climate change affects all components of the global environment system and, in turn, all components mutually interact and affect climate change through non-linear feedback processes. It is thus necessary to study the interaction between the climate and the environment, in order to comprehensively understand and predict climate and environment change. However, current relevant systems are limited to particular areas and do not sufficiently support the mutual linking of research studies. Therefore, this study develops prototype a GIS based integrated DB management system for supporting the climate and environment data storage, management and distribution. The integrated DB management system was developed using VB.NET languages and ArcObjects component. First, considering the demands of climate environment experts, the study areas are selected and the methods of data management and utilization were defined. In addition, a location-based GIS DB was created in order to aid in understanding climate change through visual representation. Finally, the integrated DB management system provides an efficient data management and distribution data and it creates synergistic effect on climate and environment study. It also contributes significantly to the comprehensive diagnosis and prediction of climate change and environment systems.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.403-411
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• 2010

Essentials of understanding the geochemical evolution and geophysical processes in Earth's system are macroscopic properties and atomistic (and electronic) structures of Earth materials. Recent advances in quantum calculations based on the density functional theory allow us to unveil the previously unknown details of local atomic structures in diverse silicates in Earth's interior. Here, we report the O K-edge ELNES (energy-loss near-edge structure; ELNES) spectra and PLDOS (partial local density of states) for oxygen atoms in ${\alpha}$-quartz and stishovite using the quantum calculations based on FP-LAPW (full potential linearized augmented plane wave). The calculated O K-edge ELNES spectrum of ${\alpha}$-quartz shows a strong peak at ~538 eV due to comer-sharing oxygen linking two $SiO_4$ tetrahedra and that for stishovite shows two distinct peaks at ~537 and ~543 eV corresponding to edge-sharing oxygen linking $SiO_6$ octahedra. The significant differences in spectral features of O K-edge ELNES spectra suggest that the O K-edge features can be useful indicator to distinguish various oxygen sites in diverse crystal and amorphous silicates in the Earth's interior.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2000.11a
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• pp.233-236
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• 2000

산업발달과 더불어 급속한 속도로 오염되고 있는 환경문제는 날로 두드려져 그린하우스 효과, 산성비 등의 출현과 더불어 세계 곳곳의 기후이변을 야기하였다. 그 원인은 지구상에서 빠른 산업화 및 과학화로 인하여 화석연료의 과다사용과 그 매연으로 인한 지구환경의 불균형을 초래하였기 때문이며, 지구온난화는 그 좋은 예라고 할 수 있다. 따라서 지구환경 보전문제로서 새로운 유독성 오염물질의 처리기술이 요구되며 에너지 고갈을 대비한 비에너지 소비성 분해기술의 확보가 시급한 실정이다. 그러므로 태양에너지와 같은 무공해 에너지원을 driving force 로 활용하여 유독성 오염물질을 상온에서 완전 분해하여 전혀 무해한 물질로 분해하는 시스템의 개발은 필수적이다.(중략)

• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.293-306
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• 1999

Solar activities ejecting high energy particles influence satellites and satellite communications as well as perturb geomagnetic fields. To understand space environments near the Earth being influenced by the Sun, we must study about the magnetosphere, the ionosphere, and the atmosphere beforehand. To study this issue, we investigate some ionospheric models, atmospheric models and geomagnetic field models : IRI(International Reference Ionosphere), PIM(Parameterized Ionospheric Model) and IGRF(International Geomagnetic Reference Field). We develop the models and build a web site to serve IRI, PIM and IGRF model on the internet so that one can easily get information of daily and global ionospheric and geomagnetic variations.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.359-366
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• 2008

전 세계적으로 기후변화와 환경변화로 인한 재난, 재해의 발생 빈도가 빈번해지고 규모가 커지면서 지구시스템의 변화를 이해, 감시, 예측하기 위한 지구관측(Earth Observation)관련 국제협력이 강화되고 있다. 이에 지구관측에 필수적인 원격탐사 자료를 이용한 공중모니터링의 중요성이 매우 커지고 있다. 이와 같은 상황에서 이 논문은 국내외 공중모니터링 관련 해외 협력체계 및 연구 현황을 살펴본 후, 국내의 공중모니터링 체계의 발전방향에 대하여 연구 및 기술적 측면, 조직 및 제도적 측면, 전략적 측면에서 논의하였다. 이 연구의 결과는 체계적인 공중모니터링 방안 수립에 대한 토대를 제공하고 향후 국내 전지구관측시스템(Global Earth Observation System of Systems) 구축을 위한 기초적 자료로 사용될 수 있을 것으로 기대된다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.276-290
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• 2023

Several efforts in Korea are currently underway with the goal of commercializing autonomous vehicles. Hence, various studies are emerging on autonomous vehicles that drive safely and quickly according to operating guidelines. The current study examines the path search of an autonomous vehicle from a microscopic viewpoint and tries to prove the efficiency required by learning the lane change of an autonomous vehicle through Deep Q-Learning. A SUMO was used to achieve this purpose. The scenario was set to start with a random lane at the starting point and make a right turn through a lane change to the third lane at the destination. As a result of the study, the analysis was divided into simulation-based lane change and simulation-based lane change applied with Deep Q-Learning. The average traffic speed was improved by about 40% in the case of simulation with Deep Q-Learning applied, compared to the case without application, and the average waiting time was reduced by about 2 seconds and the average queue length by about 2.3 vehicles.