• Geophysics and Geophysical Exploration
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• v.25 no.3
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• pp.99-108
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• 2022

Among induced polarization (IP) methods, spectral IP (SIP) uses alternating current as a transmission source to measure amplitudes and phase of complex electrical resistivity at each source frequency, which disperse with respect to source frequencies. The frequency dependence, which can be explained by a relaxation model such as Cole-Cole model or equivalent models, is analyzed to estimate SIP parameters from dispersion curves of complex resistivity employing multi-objective optimization (MOO). The estimation uses a generic algorithm to optimize two objective functions minimizing data misfits of amplitude and phase based on Cole-Cole model, which is most widely used to explain IP relaxation effects. The MOO-based estimation properly recovered Cole-Cole model parameters for synthetic examples but hardly fitted for the real laboratory measures ones, which have relatively smaller values of phases (less than about 10 mrad). Discrepancies between scales for data misfits of amplitude and phase, used as parameters of MOO method, and it is in necessity to employ other methods such as machine learning, which can deal with the discrepancies, to estimate SIP parameters from dispersion curves of complex resistivity.

• Geophysics and Geophysical Exploration
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• v.25 no.4
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• pp.214-216
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• 2022

Distributed acoustic sensing (DAS), an increasingly growing acquisition technique in the oil and gas exploration and seismology fields, has been used to record seismic signals using optical cables as receivers. With the development of imaging methods for DAS data, full waveform inversion (FWI) is been applied to DAS data to obtain high-resolution property models such as P- and S-velocity. However, because the DAS systems measure strain from the phase distortion between two points along optical cables, DAS data must be transformed from strain to particle velocity for FWI algorithms. In this study, a plane-wave FWI algorithm based on the relationship between strain and horizontal particle velocity in the plane-wave assumption is proposed to apply FWI to DAS data. Under the plane-wave assumption, strain equals the horizontal particle velocity, which is scaled by the velocity at the receiver position. This relationship was confirmed using a numerical experiment. Furthermore, 4-layer and modified Marmousi-2 velocity models were used to verify the applicability of the proposed FWI algorithm in various survey environments. The proposed FWI was implemented in land and marine survey environments and provided high-resolution P- and S-velocity models.

• Journal of Soil and Groundwater Environment
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• v.28 no.spc
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• pp.40-54
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• 2023

산업혁명 이후 화석연료의 광범위한 사용, 삼림 벌채, 토지사용의 변화 등과 같은 인위적 활동은 대기 중 온실가스(GHGs, greenhouse gases) 농도를 지속적으로 증가시켜 지구의 기후위기를 유발하였다. 우리나라의 경우 최근 30년 사이 평균 온도가 1.4℃ 상승하였으며, 국제사회의 일원으로 책임을 다하기 위해 2016년 11월 3일 파리협정을 비준하였다. 이에 파리협정의 목표인 산업화 이전 대비 지구 평균온도 상승을 2℃ 아래, 가능한 1.5℃ 아래로 억제하기 위해 2050년까지 CO₂ 순배출량을 0으로 만들어야 하며, 이를 위해 다양한 정책 마련과 함께 경제 및 사회 전반에 걸쳐 많은 노력이 경주되고 있는 실정이다. 탄소중립을 달성하기 위해서는 첫 번째로 GHGs 배출을 줄이고, 두번째로 대기에서 CO₂ 포집을 촉진하기 위해 현재 가동되는 다양한 산업분야의 생산 시스템을 개혁하는 것이 가장 중요한 과제로 고려되고 있다. 그동안 지하수토양 관련 연구분야에서는 지속가능성(sustainability), 복원성(resilience), 녹색성장(green growth) 등과 같은 사회적 요구에 부응하여, 녹색정화(green remediation), 자연 저감(natural attenuation), 탄소포집저장(carbon capture and sequestration), 지열발전등의 기술이 초기단계로 개발이 되고 연구가 되어 왔다. 이러한 기존 연구들은 탄소중립2050의 달성을 위해 고도화되어야하며, 추가적으로 자연 및 인위기원 탄소배출 연구, 토양의 역할을 고려한 저탄소 토지이용 기술, 광물탄산화 등의 연구 및 기술개발이 필요하다고 판단된다. 본 논문에서는 탄소중립2050의 간단한 내용과 함께, 이를 달성하기 위한 지하수토양 분야의 혁신기술 및 선도연구를 소개하였다.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.817-830
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• 2023

This study investigates the age of the surficial rocks in the Arunta region using Uranium-Lead (U-Pb) geochronological dating. Rock samples were collected at four locations, Cattle-Water Pass (CP 1610), Gough Dam (GD 1622 and GD 1610), and London-Eye (LE 1601), within the Strangways Metamorphic Complex and crushed by selFragging. Subsequently, the zircon grains were imaged using Cathodoluminescence (CL) analysis and the U-Pb (uranium and lead) isotope ratios and the chrono-stratigraphy were measured. The imaged zircon revealed an anomalous heterogeneous crystal structure. Ellipses of the samples at locations GD1601, CP1610, and GD1622 fall below the intercept indicating the ages produced discordant patterns, whereas LE1601 intersects the Concordia curve at two points, implying the occurrence of an event of significant impact. For the rock sample at CP1610, the estimated mean age is 1742.2 ± 9.2 Ma with mean squared weighted deviation (MSWD) = 0.49 and probability of equivalence of 0.90; 1748 ± 15 Ma - MSWD = 1.02 and probability of equivalence of 0.40 for GD1622; and 1784.4 ± 9.1 Ma with MSWD of 1.09 and probability of equivalence of 0.37 for LE1601. But for samples at GD1601, two different age groups with different means occurred: 1) below the global mean (1792.2 ± 32 Ma) estimated at 1738.2 ± 14 Ma with MSWD of 0.109 and probability of equivalence of 0.95 and 2) above it with mean of 1838.22 ± 14 Ma, MSWD of 1.6 and probability of equivalence of 0.95. Analysis of the zircon grains has shown a discrepancy in the age range between 1700 Ma and 1800 Ma compared to the ASO dated to have occurred between 440 and 300 Ma. Moreover, apparent similarity in age of the core and rim means that the mineral crystallized relatively quickly without significant interruptions and effect on the isotopic system. This may have constraint the timing and extent of geological events that might have affected the mineral, such as metamorphism or hydrothermal alteration.

• Korean Journal of Remote Sensing
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• v.39 no.5_2
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• pp.743-754
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• 2023

The global occurrence of myriad natural disasters and incidents, catalyzed by climate change and extreme meteorological conditions, has engendered substantial human and material losses. International organizations such as the International Charter have established an enduring collaborative framework for real-time coordination to provide high-resolution satellite imagery and geospatial information. These resources are instrumental in the management of large-scale disaster scenarios and the expeditious execution of recovery operations. At the national level, the operational deployment of advanced National Earth Observation Satellites, controlled by National Geographic Information Institute, has not only catalyzed the advancement of geospatial data but has also contributed to the provisioning of damage analysis data for significant domestic and international disaster events. This special edition of the National Disaster Management Research Institute delineates the contemporary landscape of major disaster incidents in the year 2023 and elucidates the strategic blueprint of the government's national disaster safety system reform. Additionally, it encapsulates the most recent research accomplishments in the domains of artificial satellite systems, information and communication technology, and spatial information utilization, which are paramount in the institution's disaster situation management and analysis efforts. Furthermore, the publication encompasses the most recent research findings relevant to data collection, processing, and analysis pertaining to disaster cause and damage extent. These findings are especially pertinent to the institute's on-site investigation initiatives and are informed by cutting-edge technologies, including drone-based mapping and LiDAR observation, as evidenced by a case study involving the 2023 landslide damage resulting from concentrated heavy rainfall.

• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1075-1084
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• 2023

Satellite-derived data is collected by observing the Earth and is used in various fields such as national defense, natural disasters, location-based services, infrastructure, environment, energy, marine, and insurance. This study aims to present the virtuous cycle structure of the satellite information data industry and the business ecosystem model of the industry. As a research method, cases were collected and categorized from the following areas: literature, online, application, and content. The results show that the ecosystem model of the satellite information data industry provides an approach to content services in public and commercial areas, and develops various algorithmic technologies to facilitate content production and services at the level of complex general-purpose technologies. Second, in terms of content typology, satellite information data can be subdivided into monitoring content, urban space monitoring content, and satellite information content. Third, the consumption value of satellite content could be subdivided into informational value, environmental, social and governance (ESG) value, educational value, and content value. In order to expand the global content market, Korea will need to focus on creating an ecosystem for the satellite information industry and discovering differentiated content. It will also need to increase the popularization and accessibility of data to the general public and promote the Korean K-Satellite Information Data Industry ecosystem through government support, policy efforts, and policies such as establishing legal systems, increasing investment, and training human resources.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.3
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• pp.182-196
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• 2023

Accurate and timely estimation of crop yields is crucial for various purposes, including global food security planning and agricultural policy development. Remote sensing techniques, particularly using vegetation indices (VIs), have show n promise in monitoring and predicting crop conditions. However, traditional VIs such as the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) have limitations in capturing rapid changes in vegetation photosynthesis and may not accurately represent crop productivity. An alternative vegetation index, the near-infrared reflectance of vegetation (NIRv), has been proposed as a better predictor of crop yield due to its strong correlation with gross primary productivity (GPP) and its ability to untangle confounding effects in canopies. In this study, we investigated the potential of NIRv in estimating crop yield, specifically for corn and soybean crops in major crop-producing regions in 14 states of the United States. Our results demonstrated a significant correlation between the peak value of NIRv and crop yield/area for both corn and soybean. The correlation w as slightly stronger for soybean than for corn. Moreover, most of the target states exhibited a notable relationship between NIRv peak and yield, with consistent slopes across different states. Furthermore, we observed a distinct pattern in the yearly data, where most values were closely clustered together. However, the year 2012 stood out as an outlier in several states, suggesting unique crop conditions during that period. Based on the established relationships between NIRv peak and yield, we predicted crop yield data for 2022 and evaluated the accuracy of the predictions using the Root Mean Square Percentage Error (RMSPE). Our findings indicate the potential of NIRv peak in estimating crop yield at the county level, with varying accuracy across different counties.

• Journal of the Daesoon Academy of Sciences
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• v.47
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• pp.39-63
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• 2023

Modern medical science tends to categorize addiction as a kind of disease, but a Taoist world-view would not consider addiction to be a disease. Taoists do not have a concept of addiction as an eternal substance. Within the Taoist world-view, human beings are meant to live in harmony with the transformative cycles of nature. Human beings achieve self-realization through balancing themselves with nature. This is what is meant by Self-Realization in Harmony with Nature. There is no disease known as addiction when one's life is in harmony with nature. There are two main principles in the Taoist medical worldview. First, is the theory of correspondences. This theory of correspondences is the foundational to Taoism's value-neutral world-view wherein humans are seen as working together with Heaven and Earth in correlative relationships to create harmonious societies. Second, is the principle of harmony and balance in the Universe. One creature can be in harmony with other creatures and learn to appreciate the interconnectedness of all living beings. Survival of the forest is vital to the survival of natural harmony, balance, morality, and environment. The vitality of the human body depends on the movement of Qi energy. According to the principles of Korean traditional medicine, all human problems stem from the mind. There is no madness, no illness, no tempting fate, and even no death outside of what stems from the mind. Within the human body, there are two principles behind energy systems: harmony and balance. When human beings achieve the state of homeostasis, they obtain Qi flows which are associated with the various organs. In doing so, they can always maintain a healthy state of life in accordance with the cosmic rhythm. Taoist philosophy contains advice that prevents addiction. Empty your mind of all thought. Let your heart be peaceful. Finally, all worries are washed away by the cosmic wave.

• Geophysics and Geophysical Exploration
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• v.8 no.4
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• pp.270-279
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• 2005

Under the research project supported by Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT), we have conducted the development of GPR systems for landmine detection. Until 2005, we have finished development of two prototype GPR systems, namely ALIS (Advanced Landmine Imaging System) and SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar). ALIS is a novel landmine detection sensor system combined with a metal detector and GPR. This is a hand-held equipment, which has a sensor position tracking system, and can visualize the sensor output in real time. In order to achieve the sensor tracking system, ALIS needs only one CCD camera attached on the sensor handle. The CCD image is superimposed with the GPR and metal detector signal, and the detection and identification of buried targets is quite easy and reliable. Field evaluation test of ALIS was conducted in December 2004 in Afghanistan, and we demonstrated that it can detect buried antipersonnel landmines, and can also discriminate metal fragments from landmines. SAR-GPR (Synthetic Aperture Radar-Ground Penetrating Radar) is a machine mounted sensor system composed of B GPR and a metal detector. The GPR employs an array antenna for advanced signal processing for better subsurface imaging. SAR-GPR combined with synthetic aperture radar algorithm, can suppress clutter and can image buried objects in strongly inhomogeneous material. SAR-GPR is a stepped frequency radar system, whose RF component is a newly developed compact vector network analyzers. The size of the system is 30cm x 30cm x 30 cm, composed from six Vivaldi antennas and three vector network analyzers. The weight of the system is 17 kg, and it can be mounted on a robotic arm on a small unmanned vehicle. The field test of this system was carried out in March 2005 in Japan.

• Journal of Science Education
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• v.42 no.1
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• pp.27-48
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• 2018

The purposes of this study are to derive suggestions and implications to improve the continuity of Korean Science & Practical Arts (Technology Home Economics) curricula through international comparative analysis with focus on the science curricula or standards in five countries (Canada, New Zealand, Singapore, the United States, Korea). Original documents of the national curriculums or standards of each country collected from NCIC comparatively analyzed the big concepts of the 'system' and 'energy' based on features of related components of curriculum contents, vertical, and lateral connectivity. The results indicated that the big concepts of systems and energy were used internationally to consider the curriculum continuity. In most countries, the big concept of system was used as a framework to integrate science with technology or other contents. In particular, it was also utilized to strengthen vertical and lateral connectivity in earth science and space science contents area. In the comparison of countries for the system as the big concept, New Zealand focused interrelationship between system and human activities, systems' interaction, levels and features of system concept for the linkage between grades and subjects on the basis of level. In the case of Canada and Singapore, science and technology are combined to strengthen contents' connection. However, the revised 2015 curriculum has a lack of continuity and sequence because the concepts of system and energy were concentrated on a specific grade and contents' area. The curriculum was not developed systematically for multiple grades according to their levels. In conclusion, Korean science curriculum requires sufficient understanding of students' learning and research on learning progressions and curriculum continuity. In addition, it is very important to constitute the curriculum based on the vertical and lateral connectivity in order to improve science education and to foster students' key competencies and abilities.