• The Journal of Engineering Geology
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• v.32 no.4
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• pp.611-625
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• 2022

One of the applications of geomagnetic paleo-secular variation (PSV) is the age dating of archeological remains (i.e., the archeomagnetic dating technique). This application requires the local model of PSV that reflects non-dipole fields with regional differences. Until now, the tentative Korean paleosecular variation (t-KPSV) calculated based on JPSV (SW Japanese PSV) has been applied as a reference curve for individual archeomagnetic directions in Korea. However, it is less reliable due to regional differences in the non-dipole magnetic field. Here, we present PSV curves for AD 1 to 600, corresponding to the Korean Three Kingdoms (including the Proto Three Kingdoms) Period, using the results of archeomagnetic studies in the Korean Peninsula and published research data. Then we compare our PSV with the global geomagnetic prediction model and t-KPSV. A total of 49 reliable archeomagnetic directional data from 16 regions were compiled for our PSV. In detail, each data showed statistical consistency (N > 6, 𝛼₉₅ < 7.8°, and k > 57.8) and had radiocarbon or archeological ages in the range of AD 1 to 600 years with less than ±200 years error range. The compiled PSV for the initial six centuries (KPSV0.6k) showed declination and inclination in the range of 341.7° to 20.1° and 43.5° to 60.3°, respectively. Compared to the t-KPSV, our curve revealed different variation patterns both in declination and inclination. On the other hand, KPSV0.6k and global geomagnetic prediction models (ARCH3K.1, CALS3K.4, and SED3K.1) revealed consistent variation trends during the first six centennials. In particular, the ARCH3K.1 showed the best fitting with our KPSV0.6k. These results indicate that contribution of the non-dipole field to Korea and Japan is quite different, despite their geographical proximity. Moreover, the compilation of archeomagnetic data from the Korea territory is essential to build a reliable PSV curve for an age dating tool. Lastly, we double-check the reliability of our KPSV0.6k by showing a good fitting of newly acquired age-controlled archeomagnetic data on our curve.

• The Journal of Engineering Geology
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• v.32 no.4
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• pp.697-723
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• 2022

Data-driven models to predict groundwater levels 30 days in advance were developed for 12 groundwater monitoring stations in the middle-Jeju watershed, Jeju Island. Stacked long short-term memory (stacked-LSTM), a deep learning technique suitable for time series forecasting, was used for model development. Daily time series data from 2001 to 2022 for precipitation, groundwater usage amount, and groundwater level were considered. Various models were proposed that used different combinations of the input data types and varying lengths of previous time series data for each input variable. A general procedure for deep-learning-based model development is suggested based on consideration of the comparative validation results of the tested models. A model using precipitation, groundwater usage amount, and previous groundwater level data as input variables outperformed any model neglecting one or more of these data categories. Using extended sequences of these past data improved the predictions, possibly owing to the long delay time between precipitation and groundwater recharge, which results from the deep groundwater level in Jeju Island. However, limiting the range of considered groundwater usage data that significantly affected the groundwater level fluctuation (rather than using all the groundwater usage data) improved the performance of the predictive model. The developed models can predict the future groundwater level based on the current amount of precipitation and groundwater use. Therefore, the models provide information on the soundness of the aquifer system, which will help to prepare management plans to maintain appropriate groundwater quantities.

• Journal of Wetlands Research
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• v.24 no.3
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• pp.204-212
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• 2022

The LID technique began to be applied in Korea after 2009, and LID facilities are installed and operated for rainwater management in business districts such as the Ministry of Environment, the Ministry of Land, Infrastructure and Transport, and LH Corporation, public institutions, commercial land, housing, parks, and schools. However, looking at domestic cases, the application cases and operation periods are insufficient compared to those outside the country, so appropriate design standards and measures for operation and maintenance are insufficient. In particular, LID facilities constructed using LID techniques need to maintain the environment inside LID facilities because hydrological and environmental effects are expressed by material circulation and energy flow. The LID facility is designed with the treatment capacity planned for the water circulation target, and the proper maintenance, vegetation, and soil conditions are periodically identified, and the efficiency is maintained as much as possible. In other words, the soil created in LID is a very important design element because LID facilities are expected to have effects such as water pollution reduction, flood reduction, water resource acquisition, and temperature reduction while increasing water storage and penetration capacity through water circulation construction. In order to maintain and manage the functions of LID facilities accurately, the current state of the facilities and the cycle of replacement and maintenance should be accurately known through various quantitative data such as soil contamination, snow removal effects, and vegetation criteria. This study was conducted to investigate the current status of LID facilities installed in Korea from 2009 to 2020, and analyze soil changes through the continuity and current status of LID facilities applied over the past 10 years after collecting soil samples from the soil layer. Through analysis of Saturn, organic matter, hardness, water contents, pH, electrical conductivity, and salt, some vegetation-type LID facilities more than 5 to 7 years after construction showed results corresponding to the lower grade of landscape design. Facilities below the lower level can be recognized as a point of time when maintenance is necessary in a state that may cause problems in soil permeability and vegetation growth. Accordingly, it was found that LID facilities should be managed through soil replacement and replacement.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.27 no.3
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• pp.127-143
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• 2022

Recently, many attempts to run numerical ocean models in cloud computing environments have been tried actively. A cloud computing environment can be an effective means to implement numerical ocean models requiring a large-scale resource or quickly preparing modeling environment for global or large-scale grids. Many commercial and private cloud computing systems provide technologies such as virtualization, high-performance CPUs and instances, ether-net based high-performance-networking, and remote direct memory access for High Performance Computing (HPC). These new features facilitate ocean modeling experimentation on commercial cloud computing systems. Many scientists and engineers expect cloud computing to become mainstream in the near future. Analysis of the performance and features of commercial cloud services for numerical modeling is essential in order to select appropriate systems as this can help to minimize execution time and the amount of resources utilized. The effect of cache memory is large in the processing structure of the ocean numerical model, which processes input/output of data in a multidimensional array structure, and the speed of the network is important due to the communication characteristics through which a large amount of data moves. In this study, the performance of the Regional Ocean Modeling System (ROMS), the High Performance Linpack (HPL) benchmarking software package, and STREAM, the memory benchmark were evaluated and compared on commercial cloud systems to provide information for the transition of other ocean models into cloud computing. Through analysis of actual performance data and configuration settings obtained from virtualization-based commercial clouds, we evaluated the efficiency of the computer resources for the various model grid sizes in the virtualization-based cloud systems. We found that cache hierarchy and capacity are crucial in the performance of ROMS using huge memory. The memory latency time is also important in the performance. Increasing the number of cores to reduce the running time for numerical modeling is more effective with large grid sizes than with small grid sizes. Our analysis results will be helpful as a reference for constructing the best computing system in the cloud to minimize time and cost for numerical ocean modeling.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.694-709
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• 2021

Purpose: In this study, earthquake-induced landslide risk assessment was conducted to provide basic data for efficient and preemptive damage prevention by selecting the erosion control work before the earthquake and the prediction and restoration priorities of the damaged area after the earthquake. Method: The study analyzed the previous studies abroad to examine the evaluation methodology and to derive the evaluation factors, and examine the utilization of the landslide hazard map currently used in Korea. In addition, the earthquake-induced landslide hazard map was also established on a pilot basis based on the fault zone and epicenter of Pohang using seismic attenuation. Result: The earthquake-induced landslide risk assessment study showed that China ranked 44%, Italy 16%, the U.S. 15%, Japan 10%, and Taiwan 8%. As for the evaluation method, the statistical model was the most common at 59%, and the physical model was found at 23%. The factors frequently used in the statistical model were altitude, distance from the fault, gradient, slope aspect, country rock, and topographic curvature. Since Korea's landslide hazard map reflects topography, geology, and forest floor conditions, it has been shown that it is reasonable to evaluate the risk of earthquake-induced landslides using it. As a result of evaluating the risk of landslides based on the fault zone and epicenter in the Pohang area, the risk grade was changed to reflect the impact of the earthquake. Conclusion: It is effective to use the landslide hazard map to evaluate the risk of earthquake-induced landslides at the regional scale. The risk map based on the fault zone is effective when used in the selection of a target site for preventive erosion control work to prevent damage from earthquake-induced landslides. In addition, the risk map based on the epicenter can be used for efficient follow-up management in order to prioritize damage prevention measures, such as to investigate the current status of landslide damage after an earthquake, or to restore the damaged area.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.864-881
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• 2021

Purpose: This study aims is to provide a total care solution preventing disaster based on Big Data and AI technology and to service safety considered by individual situations and various risk characteristics. The purpose is to suggest a method that customized comprehensive index services to prevent and respond to safety accidents for calculating the living safety index that quantitatively represent individual safety levels in relation to daily life safety. Method: In this study, we use method of mixing AHP(Analysis Hierarchy Process) and Likert Scale that extracted from consensus formation model of the expert group. We organize evaluation items that can evaluate life safety prevention services into risk indicators, vulnerability indicators, and prevention indicators. And We made up AHP hierarchical structure according to the AHP decision methodology and proposed a method to calculate relative weights between evaluation criteria through pairwise comparison of each level item. In addition, in consideration of the expansion of life safety prevention services in the future, the Likert scale is used instead of the AHP pair comparison and the weights between individual services are calculated. Result: We obtain result that is weights for life safety prevention services and reflected them in the individual risk index calculated through the artificial intelligence prediction model of life safety prevention services, so the comprehensive index was calculated. Conclusion: In order to apply the implemented model, a test environment consisting of a life safety prevention service app and platform was built, and the efficacy of the function was evaluated based on the user scenario. Through this, the life safety index presented in this study was confirmed to support the golden time for diagnosis, response and prevention of safety risks by comprehensively indication the user's current safety level.

• Ecology and Resilient Infrastructure
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• v.9 no.1
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• pp.68-76
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• 2022

In this study, the Habitat Suitability Index (HSI) was calculated in the Miho stream of the Geum river system, and the environmental ecological flow by point was evaluated. Two points (St.3 and St.8) representing the up and downstream of Miho Stream were selected, in order to calculate the Habitat Suitability Index, the depth and velocity at point where each species is appeared were investigated. The Habitat Suitability Index (HSI) was calculated by the Washington Department of Fish and Wildlife (WDFW) method using the number collected by water depth and velocity section and the results of the flow rate survey. Two target species were selected in this study; dominant species and swimming species sensitive to flow. In the case of a single species of Zacco platypus, the water depth was 0.1 - 0.5 m and the velocity was 0.2 - 0.5 m/s. For species of swimming fish, the water depth was 0.2 - 0.5 m and the velocity was 0.2 - 0.5 m/s. The discharge-Weighted Useable Area (WUA) relationship curve and habitat suitability distribution were simulated at the Miho Stream points St.3 and St.8. At the upstream St.3 of Miho Stream, the optimal discharge was simulated as 4.0 m³/s for swimming fishes and 2.7 m³/s for Zacco platypus. At the downstream point of St.8, species of swimming fish were simulated as 8.8 m³/s and Zacco platypus was simulated as 7.6 m³/s. In both points, the optimal discharge of swimming fish was over estimated. This is a result that the Habitat Suitability Index for swimming fish requires a faster flow rate than the habitat conditions of the Zacco platypus. In the calculation of the minimum discharge, the discharge of Zacco platypus is smaller and is evaluated to provide more Weighted Useable Area. In the case of swimming fishes, narrow range of depth and velocity increases the required discharge and relatively decreases the Weighted Useable Area. Therefore, when calculating the Habitat Suitability Index for swimming fishes, it is more advantageous to calculate the index including the habitat of all fish species than to narrow the range.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.2
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• pp.34-43
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• 2022

This study compared the characteristics of cultural heritage in China and Vietnam, which have developed in the relationship of mutual geopolitical and cultural influence in history, and the following conclusions were made. First, the definition of cultural heritage in China and Vietnam has similar meanings in both countries. In the case of cultural heritage classification, both countries introduced the legal concept of intangible cultural heritage through UNESCO, and have similarities in terms of intangible cultural heritage. Second, while China has separate laws for managing tangible and intangible cultural heritages, Vietnam integrally manages the two types of cultural heritages under a single law. Vietnam has a slower introduction of the concept of cultural heritage than China, but it shows high integration in terms of system. Third, cultural heritages in both China and Vietnam are graded, which is applied differently depending on the type of heritage. The designation method has a similarity in which the two countries have a vertical structure and pass through steps. By restoring the value of heritage and complementing integrity through such a step-by-step review, balanced development across the country is being sought through tourism to enjoy heritage and create economic effects. Fourth, it was confirmed that the cultural heritage management organization has a central government management agency in both countries, but in China, the authority of local governments is higher than that of Vietnam. In addition, unlike Vietnam, where tangible and intangible cultural heritage are managed by an integrated institution, China had a separate institution in charge of intangible cultural heritage. Fifth, China is establishing a conservation management policy focusing on sustainability that harmonizes the protection and utilization of heritage. Vietnam is making efforts to integrate the contents and spirit of the agreement into laws, programs, and projects related to cultural heritage, especially intangible heritage and economic and social as a whole. However, it is still dependent on the influence of international organizations. Sixth, China and Vietnam are now paying attention to intangible heritage recently introduced, breaking away from the cultural heritage protection policy centered on tangible heritage. In addition, they aim to unite the people through cultural heritage and achieve the nation's unified policy goals. The two countries need to use intangible heritage as an efficient means of preserving local communities or regions. A cultural heritage preservation network should be established for each subject that can integrate the components of intangible heritage into one unit to lay the foundation for the enjoyment of the people. This study has limitations as a research stage comparing the cultural heritage system and preservation management status in China and Vietnam, and the characteristic comparison of cultural heritage policies by type remains a future research task.

• Analyses & Alternatives
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• v.6 no.1
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• pp.115-162
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• 2022

The Rules of the Workers' Party of Korea (WPK), revised at the eighth Party Congress in 2021, reflect the Kim Jong Un regime's changes in strategic lines and ideological justifications on North Korea's socialism and communism, and its recent stances against the external environment. Moreover, they contain critical changes in the party's organizational system encompassing the central and the provinces. This study explores the organizational changes of the "monolithic guidance system of the party core" stipulated by the new party rules in January 2021, based on the analysis of the entire nine revised rules of the WPK since 1945. In the 2021 Party Congress, the Kim Jong Un regime, which officially came to power after the fourth Party Conference in 2012, has institutionalized the monolithic guidance system centered on the party core, or the head of state, Kim Jong Un. The newly set leadership and execution system, which reorganized party, government, and military organizational structure and accompanied the relevant personnel changes, was derived from the attempts for reinstating the Kim Jong Un regime as a more normalized party-state structure before its 10th year in power in April 2022. The "monolithic leadership system of the party core" established a system of "organizational leadership" through the organization of the Central Committee, directed by the Party Head, or General Secretary. The institutionalization of the new system resulted from the ten-year development of the revival of the party-state structure, which compromised the status of the military and reconfirmed the party's control of the military. This study explains the new system from the perspectives of both institutionalization and top-down unity, shedding light on the new party-military-government relations of the Kim Jong Un regime. The analysis contributes to a better understanding and forecasting of the Kim Jong Un regime's governance, which currently strengthens the monolithic leadership system as a crisis management system in the face of the "triple hardships" of sanctions, Covid and disaster.

• Industry Promotion Research
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• v.7 no.3
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• pp.27-42
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• 2022

Local education autonomy aims to improve the quality of life of local residents and to realize education considering local characteristics. For this purpose, it is necessary to strengthen the competency of local education administrative officials. This study intends to derive the competency of level 6 public officials who should play a central role in local education administrative officials, and to devise the subjects cluster and subjects of the long-term education program. The purpose of this study is to prepare a basic plan so that the education program for level 6 educational administrative officials can be developed in the future. For this study, an expert panel was composed of 20 people including education administrative officials and education program development experts. In addition, the Delphi survey was conducted three times to obtain opinions on the competency of level 6 educational administrative officials and the subjects cluster and subjects of the long-term education program. For the competency of level 6 educational administrative officials, the validity of the survey data was evaluated in the Delphi 1st survey and the validity of the revised data in the 2nd Delphi survey was conducted. And for the subjects cluster and subjects of the long-term education program for level 6 educational administrative officials, the validity of basic data was evaluated in the Delphi 2nd survey and the validity of the revised data in the 3rd Delphi survey was conducted. As a result, the competencies of level 6 educational administrative officials were extracted into nine competencies including coordination and integration competencies. And the long-term education program for level 6 educational administrative officials was developed with 13 subjects cluster and 43 subjects. And the relationship model between the competency of level 6 educational administrative officials and the subjects cluster and subjects of the long-term education program was derived. Based on the results of this study, it was proposed to operate a flexible curriculum for a long-term education program. In addition, the necessity of establishing a system that can reflect the educational training results in the actual educational field was suggested.