• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.2
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• pp.95-102
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• 2022

It is a study for the evaluation of the stability of the distribution automation system for the expansion of renewable energy. Through the Renewable Energy 3020 Implementation Plan, the government plans to expand new renewable energy and convert it to participatory energy that improves the quality of life of the people by 2030. The government has set a target of 20% of domestic supply energy for renewable energy generation by 2030. It is planning to establish more than 95 percent of its new facilities with clean energy such as solar power and wind power. By expanding the supply of renewable energy, new energy businesses and distributed power industry were fostered, and short-distance, low-voltage, and small-scale power generation were rapidly expanded rather than large-scale power development in the past. Due to this demand, the importance of power distribution facility operation has emerged and the need for distribution automation system is increasing. This paper discusses the development of a power distribution simulator for the performance and function evaluation of power distribution automation systems and presents the results of an interlocking test with the power distribution automation system. In order to introduce an advanced system into the power distribution system, it is necessary to take advantage of the transmission and distribution system. The DNP3.0 protocol is used in the distribution system and the IEC61850 protocol is used in the transmission and distribution system. It was concluded that the functions and performance of operations were satisfied when these two protocols are mixed and used in the distribution automation system.

• Journal of the Korean Institute of Landscape Architecture
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• v.50 no.2
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• pp.116-126
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• 2022

Although the 'Act on Urban Parks and Green Spaces' was revised in 2016 to provide a legal foundation for national urban parks, there was no further discussion or follow-up research for the implementation of national urban parks. This study investigates Korea's park and green space regulations and national urban park cases from across the world. It aims to analyze worldwide cases and set a course for a viable national urban park system in Korea. The importance and characteristics of national urban parks were evident after reviewing the cases of Japan, Sweden, Finland, and Canada, which have national urban park systems, and the United States and Germany, which aid city parks with national budgets. Each country determined the plans and procedures by assessing the scope of government intervention and the government's role. The importance of communication between the state and municipal governments and private sector participation and governance was recognized. A system was also formed in which local governments actively participate in the nomination, establishment, administration, and management of national urban parks. The results of this study are as follows. First, the concept of equitable national development should be implemented to activate the national urban park system. Second, the national urban park should be a land management tool that may be used to balance development and preservation. Third, a specific method of securing, constructing, administering, and operating national urban parks should be supplemented by the current legislative framework amendment. Furthermore, the establishment of a sustainable research institute is needed to comprehensively analyze parks and green space systems and make appropriate decisions.

• Journal of Korean Society of Forest Science
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• v.111 no.2
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• pp.287-301
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• 2022

This study aims to propose a crane-tip control method to intuitively control the end-effector vertically or horizontally for improving the crane work efficiency and to confirm the control performance. To verify the control performance based on experimental variables, a laboratory-scale crane was manufactured using an electric cylinder. Through a forward and reverse kinematics analysis, the crane was configured to output the position coordinates of the current crane-tip and the joint angle at each target point. Furthermore, a method of generating waypoints was used, and a dead band using lateral boundary offset (LBO) was set. Appropriate parameters were selected using bang-bang control, which confirmed that the number of waypoints and LBO radius were associated with positioning error, and the cylinder speed was related to the lead time. With increased number of waypoints and decreased LBO radius, the positioning error and the lead time also decreased as the cylinder speed decreased. Using the proportional control, when the cylinder velocity was changed at every control cycle, the lead time was greatly reduced; however, the actual control pattern was controlled by repeating over and undershoot in a large range. Therefore, proportional control was performed by additionally applying velocity gain that can relatively change the speed of each cylinder. Since the control performed with in a range of 10 mm, it was verified th at th e crane-tip control can be ach ieved with only th e proportional control to which the velocity gain was applied in a control cycle of 20 ms.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.5
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• pp.639-650
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• 2022

In areas where large-scale sediment transport occurs, it is important to apply appropriate countermeasure method because the phenomenon tends to accelerate by time duration. Among the various countermeasure methods applied so far, beach nourishment needs to be reviewed as an erosion prevention measure because the erosion pattern is mitigated and environmentally friendly depending on the particle size. In the case of beach nourishment. a detailed review is required to determine the size, range, etc., of an appropriate particle diameter. In this study, we investigated the characteristics of the related topographic change using the change in the particle size of nourishment materials, the application of partial area, and the condition under the coexistence of waves and wind as variables because those factors are hard to be analyzed and interpreted within results and limitation of that the existing numerical models are not able to calculate and result out so that it is required that phenomenon or efforts are reviewed at the same time through physical model experiments, field monitoring and etc. So we attempt to reproduce the tendency of beach erosion and deposition and predict possible phenomena in the future using machine learning techniques for phenomena that it is not able to be interpreted by numerical models. we used the hydraulic experiment results for the training data, and the accuracy of the prediction results according to the change in the training method was simultaneously analyzed. As a result of the study it was found that topographic changes using machine learning tended to be similar to those of previous studies in short-term predictions, but we also found differences in the formation of scour and sandbars.

• Journal of the Korean Society for Library and Information Science
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• v.57 no.3
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• pp.97-117
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• 2023

The purpose of this study is to suggest a mid- to long-term expansion plan to resolve the blind spot and alleviate the imbalance of public library services in Daegu City. The research methods for this purpose included literature review, related laws and statistical data analysis, case study, and opinion survey. As a result, the first service area was set as a total of 14 areas based on administrative districts(Jung-gu, Seo-gu, Nam-gu, and Dalseong-gun each have one, Dong-gu and Buk-gu each have two, and Suseong-gu and Dalseo-gu have three each). Second, the expansion scenario for public libraries in Daegu City was proposed to add 26 libraries by the final target year (2032) based on the trend of national library growth over the past 13 years (2008-2020) and the forecast for the next 10 years (2023-2032). Third, the construction scenarios for each basic local government, excluding the Daegu representative library, are as follows: One library each in Jung-gu, Seo-gu, and Nam-gu; two libraries in Suseong-gu; three libraries in Dalseong-gun; four libraries in Dong-gu; and seven libraries each in Buk-gu and Dalseo-gu. In terms of floor area, it is proposed to add a total of 17 branch libraries with a minimum legal standard of 330-2,499㎡, four central libraries with 2,500-4,999㎡ each, and four central libraries with 5,000-9,999㎡ each. On the premise of these conditions, Daegu City and public libraries should focus on creating an inclusive and open community space, creating a digital platform, strengthening the library operation and cooperation system centered on Daegu representative library, developing collections and specializing services for local hub libraries, enhancing various knowledge information and program services, managing key library indicators and improving social contribution.

• 한국정책학회보
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• v.23 no.3
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• pp.161-198
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• 2014

The various types of improper usages in the process of delivering social services have been increasingly paid to attention in South Korea. This study, relying on empirical data about the various improper behaviors, explore whether the audit activity can reduce the degree of the improper behavior. In order to estimate the impact of the audit, we use the DID(Difference in difference) method, comparing the experimental group with the audit treatment and the control group without it. We control for size(the number of Service personnel and user), types of social service (elderly, disabled, etc.), organizational forms(profit, non-profit), region(metropolitan areas, small-medium cities, rural areas), and the number times of audit (1, 2, and 3 number). Our empirical results show that the audit decreased the ratio of payment violation by about 4.02 percent, the number of violations from providers' improper payment by approximately 5.07 and the number of violations from users' improper payment by approximately 9.59. Further research is required to explore why and how the audit can decrease the improper usage in social service with rigorous theoretical models.

• Economic Analysis
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• v.27 no.4
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• pp.1-42
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• 2021

The outlook for Korea's consumer price inflation rate has a profound impact not only on the Bank of Korea's operation of the inflation target system but also on the overall economy, including the bond market and private consumption and investment. This study presents the prediction results of consumer price inflation in Korea for the next three years. To this end, first, model selection is performed based on the out-of-sample predictive power of autoregressive distributed lag (ADL) models, AR models, small-scale vector autoregressive (VAR) models, and large-scale VAR models. Since there are many potential predictors of inflation, a Bayesian variable selection technique was introduced for 12 macro variables, and a precise tuning process was performed to improve predictive power. In the case of the VAR model, the Minnesota prior distribution was applied to solve the dimensional curse problem. Looking at the results of long-term and short-term out-of-sample predictions for the last five years, the ADL model was generally superior to other competing models in both point and distribution prediction. As a result of forecasting through the combination of predictions from the above models, the inflation rate is expected to maintain the current level of around 2% until the second half of 2022, and is expected to drop to around 1% from the first half of 2023.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.2
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• pp.175-186
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• 2023

The buffer materials in disposal hole are exposed to the decay heat from spent nuclear fuels and groundwater inflow through adjacent rockmass. Since understanding of thermal-hydro-mechanical-chemical (T-H-M-C) interaction in buffer material is crucial for predicting their long-term performance and safety of disposal repository, it is necessary to investigate the heating-hydration characteristics and consequent T-H-M-C behavior of the buffer materials under disposal conditions considering geochemical factors. In response, the Korea Atomic Energy Research Institute developed a laboratory-scale 'Lab.THMC' experiment system, which characterizes the T-H-M behavior of buffer materials under different geochemical conditions by analyzing heating-hydration process and stress changes. This technical report introduces the detail design of the Lab.THMC system, summarizes preliminary experimental results, and outlines future research plans.

• Journal of Environmental Impact Assessment
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• v.32 no.2
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• pp.61-71
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• 2023

As differences in the impact of each species on a spatial scale occur, analysis at the landscape scale is necessary to evaluate the impact of a development project. In previous studies, the Incidence Function Model (IFM) based on meta population theory was used to analyze the impact of species on the environment that changes according to urban development. However, since the model was required at least 10 occupied areas, it is difficult to use it for species that are difficult to monitor such as endangered species. Therefore, we proposed the Incidence Function Model (IFM) using species distribution model to fill the species data. In addition, we reviewed whether the developed model can be used in environmental impact assessment. As a result of the analysis, the minimum occupancy of Prionailurus bengalensis on urban development decreased to 56.5% and the possibility of survival to 28.7%. We confirmed that It rapidly decreased from the reference points of 230 and 70habitats through analysis of the meta-population capacity according to the decrease in the number of habitats. These results can be assessing the environment impact of each species on habitat loss. And it can support decision-making on the minimum number and area of habitat for species protection. This study is expected to be used as basic data for environment impact assessment on before and after development projects and mitigation measures plans, thereby increasing the effectiveness of reduction plans.

• Journal of Wetlands Research
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• v.25 no.2
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• pp.83-90
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• 2023

Due to climate change, the occurrence of abnormal rainfall is increasing, and the intensity and scale of damage caused by heavy rain are increasing every year. In addition, as the frequency of heavy rains becomes more frequent, heavy rains often occur continuously, resulting in large flooding damage that has never been seen before in urban area. When near rivers and coastal areas are impermeable areas, the maximum flow increases rapidly as the rainfall intensity increases, so a comprehensive flood risk evaluation is needed considering the characteristics of the basin. In this study, the flood inundation risk evaluation was analyzed by giving scores on evaluation factors as a measure to prevent inundation in subway stations. Through the flood inundation risk evaluation process considering the comprehensive evaluation index, the flood risk evaluation was conducted on five urban railway stations with a large amount of traffic and floating population that had been inundated in the past. It is judged that by comprehensively analyzing this and establishing a inundation risk grade (grade 1 to 4) to establish a flood measure suitable for the risk grade.