• Tunnel and Underground Space
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• 제33권6호
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• pp.445-471
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• 2023

Long-term safety over millennia is the top priority consideration in the construction of disposal sites. However, ensuring the mechanical stability of deep geological repositories for spent fuel, a.k.a. radwaste, disposal during construction and operation is also crucial for safe operation of the repository. Imposing restrictions or limitations on tunnel support and lining materials such as shotcrete, concrete, grouting, which might compromise the sealing performance of backfill and buffer materials which are essential elements for the long-term safety of disposal sites, presents a highly challenging task for rock engineers and tunnelling experts. In this study, as part of an extensive exploration to aid in the proper selection of disposal sites, the anticipation of constructing a deep geological repository at a depth of 500 meters in an unknown state has been carried out. Through a review of 2D and 3D numerical analyses, the study aimed to explore the range of properties that ensure stability. Preliminary findings identified the potential range of rock properties that secure the stability of central and disposal tunnels, while the stability of the vertical tunnel network was confirmed through 3D analysis, outlining fundamental rock conditions necessary for the construction of disposal sites.

• Journal of Cadastre & Land InformatiX
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• 제54권1호
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• pp.19-32
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• 2024

This study examined the feasibility of image-based surveys by detecting objects in facilities and agricultural land using the YOLO algorithm based on drone images and comparing them with the land category by law. As a result of detecting objects through the YOLO algorithm, buildings showed a performance of detecting objects corresponding to 96.3% of the buildings provided in the existing digital map. In addition, the YOLO algorithm developed in this study detected 136 additional buildings that were not located in the digital map. Plastic greenhouses detected a total of 297 objects, but the detection rate was low for some plastic greenhouses for fruit trees. Also, agricultural land had the lowest detection rate. This result is because agricultural land has a larger area and irregular shape than buildings, so the accuracy is lower than buildings due to the inconsistency of training data. Therefore, segmentation detection, rather than box-shaped detection, is likely to be more effective for agricultural fields. Comparing the detected objects with the land category by law, it was analyzed that some buildings exist in agricultural and forest areas where it is difficult to locate buildings. It seems that it is necessary to link with administrative information to understand that these buildings are used illegally. Therefore, at the current level, it is possible to objectively determine the existence of buildings in fields where it is difficult to locate buildings.

• Journal of Korean Library and Information Science Society
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• 제54권4호
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• pp.415-436
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• 2023

In this study, we aimed to examine the level of implementation of the second comprehensive plan for promoting academic libraries (2019-2023) by analyzing key statistics of academic libraries and gathering perceptions from library staff. We analyzed the changes in major statistical indicators of libraries over the past five years. Additionally, we surveyed library staff to understand their overall perceptions of the plan and their attitudes towards the 17 sub-tasks outlined in it. The analysis of 369 survey responses revealed several key findings. Firstly, most respondents comprehended the plan well and frequently utilized it for developing their libraries' development and implementation plans. Secondly, the IPA results indicated that regardless of the type of university, there should be a continuous focus on facility improvement, teaching-learning support, and expanding access to academic resources. Efforts to develop library policies and strengthen human and financial resources were identified as crucial. Thirdly, four-year universities particularly emphasized the importance of expanding access to international academic resources compared to junior colleges. Conversely, junior colleges perceived foundational skill-building programs and inclusive services as more significant than four-year universities. The application of the IPA diagonal model revealed that the performance levels of all sub-tasks were lower than their perceived importance levels, suggesting the need for strategies to enhance effectiveness in future comprehensive plan formulation.

• Nuclear Engineering and Technology
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• 제56권3호
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• pp.803-811
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• 2024

Nuclear accidents such as Fukushima Daiichi have highlighted the potential of passive safety systems to replace or complement active safety systems as part of the overall prevention and/or mitigation strategies. In addition, passive systems are key features of Small Modular Reactors (SMRs), for which they are becoming almost unavoidable and are part of the basic design of many reactors available in today's nuclear market. Nevertheless, their potential to significantly increase the safety of nuclear power plants still needs to be strengthened, in particular the ability of computer codes to determine their performance and reliability in industrial applications and support the safety demonstration. The PASTELS project (September 2020-February 2024), funded by the European Commission "Euratom H2020" programme, is devoted to the study of passive systems relying on natural circulation. The project focuses on two types, namely the SAfety COndenser (SACO) for the evacuation of the core residual power and the Containment Wall Condenser (CWC) for the reduction of heat and pressure in the containment vessel in case of accident. A specific design for each of these systems is being investigated in the project. Firstly, a straight vertical pool type of SACO has been implemented on the Framatome's PKL loop at Erlangen. It represents a tube bundle type heat exchanger that transfers heat from the secondary circuit to the water pool in which it is immersed by condensing the vapour generated in the steam generator. Secondly, the project relies on the CWC installed on the PASI test loop at LUT University in Finland. This facility reproduces the thermal-hydraulic behaviour of a Passive Containment Cooling System (PCCS) mainly composed of a CWC, a heat exchanger in the containment vessel connected to a water tank at atmospheric pressure outside the vessel which represents the ultimate heat sink. Several activities are carried out within the framework of the project. Different tests are conducted on these integral test facilities to produce new and relevant experimental data allowing to better characterize the physical behaviours and the performances of these systems for various thermo-hydraulic conditions. These test programmes are simulated by different codes acting at different scales, mainly system and CFD codes. New "system/CFD" coupling approaches are also considered to evaluate their potential to benefit both from the accuracy of CFD in regions where local 3D effects are dominant and system codes whose computational speed, robustness and general level of physical validation are particularly appreciated in industrial studies. In parallel, the project includes the study of single and two-phase natural circulation loops through a bibliographical study and the simulations of the PERSEO and HERO-2 experimental facilities. After a synthetic presentation of the project and its objectives, this article provides the reader with findings related to the physical analysis of the test results obtained on the PKL and PASI installations as well an overall evaluation of the capability of the different numerical tools to simulate passive systems.

• Journal of the Society of Disaster Information
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• 제20권1호
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• pp.40-46
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• 2024

Purpose: In this study, in order to ensure the evacuation safety of plant facilities, we analyze the relationship between the height of smoke removal boundary walls, the presence or absence of smoke removal equipment, and evacuation safety. Method: Using fire and evacuation simulations, evacuation safety was analyzed through changes in the height of the smoke removal boundary wall, air supply volume and exhaust volume according to vertical dista. Result: In the case of visible drawings, if only 0.6m of boundary wall is used, the time below 5m reaches the shortest, and 1.2m of boundary width is 20% longer than when using smoke removal facilities. In the case of temperature, 1.2m is 20% longer than 0.6m when only the boundary width is used without smoke removal facilities. Conclusion: It was found that increasing the length of the smoke removal boundary wall could affect visibility, and installing a smoke removal facility would affect temperature. Therefore, it is determined that an appropriate smoke removal plan and smoke removal equipment should be installed in consideration of the process characteristics.

• Journal of Space Technology and Applications
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• 제3권4호
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• pp.333-341
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• 2023

This study aims to develop technology for testing and verifying the space radiation environment of miniature space components using the facilities of the domestic 100 MeV proton accelerator and the Space Component Test Facility at the Space Testing Center. As advancements in space development progress, high-performance satellites increasingly rely on densely integrated circuits, particularly in core components components like memory. The application of semiconductor components in essential devices such as solar panels, optical sensors, and opto-electronics is also on the rise. To apply these technologies in space, it is imperative to undergo space environment testing, with the most critical aspect being the evaluation and testing of space components in high-energy radiation environments. Therefore, the Space Testing Center at the Korea testing laboratory has developed a radiation testing device for memory components and conducted radiation impact assessment tests using it. The investigation was carried out using 100 MeV protons at a low flux level achievable at the Gyeongju Proton Accelerator. Through these tests, single event upsets observed in memory semiconductor components were confirmed.

• Land and Housing Review
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• 제15권3호
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• pp.79-95
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• 2024

Over the past decade, urban regeneration projects have been actively promoted nationwide in South Korea, leading to the establishment of numerous community facilities aimed at fostering community engagement and revitalization. Recently, the need for diagnostic tools to provide appropriate support and guidance for the sustainable operation of these facilities has been increasingly emphasized. However, a comprehensive manual or nationwide standard approach remains lacking. As such, this study aims to propose evaluation criteria and their application methods for the periodic operational assessment of those facilities. First, through a review of previous studies, candidate indicators were identified. After that, preliminary indicators and frameworks were determined through expert consultations, followed by surveys conducted with 65 experts to finalize the evaluation indicators. The survey results highlighted the importance of 'Value Creation (VC)' and 'Operation Management (OM)' as key aspects of facility evaluation. In assessing VC, key factors include enhancing community vitality, strengthening local capacity, providing tailored functions for the community, and contributing to the local economy. In constructing OM, the focus lies on operational system, financial management, operational personnel, and economic viability and sustainability. This study proposes an evaluation framework that includes the final evaluation indicators and available data sources for each indicator, and a pilot test was conducted to verify its applicability. Moreover, the study suggests directions for utilizing the evaluation criteria and methods for applying indicators tailored to the characteristics of individual facilities.

• Journal of Korea Port Economic Association
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• 제40권2호
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• pp.191-204
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• 2024

In this study, AHP-based production management job training was developed for MPE companies in the aviation logistics industry. The AHP model was designed with upper and lower classes. Purchase management competency, material management competency, process management competency, and SCM competency were selected as factors of the upper class of production management job training. Lower class evaluation factors were selected for each upper class. As a result of AHP analysis, the relative importance of the upper class evaluation factors was found in the order of SCM competency (0.322), process management competency (0.314), material management competency (0.201), and purchase management competency (0.163). Among the upper classes, it was analyzed that the importance of SCM competency and process management competency was high. The final priority of evaluation factors for the development of the production management curriculum of MPE companies in the aviation logistics industry was analyzed as follows. First, supply chain performance management, which is the lower layer of SCM competency, was analyzed as the top priority factor, and the priorities of evaluation factors were derived such as facility preservation management, which is the lower layer of SCM competency, supply chain production operation, which is the lower layer of SCM competency, process quality management, which is the lower layer of SCM competency, supply chain transportation management, and supply chain supply plan, which are the lower layers of SCM competency

• The Journal of Bigdata
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• 제8권2호
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• pp.73-82
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• 2023

With 78% of current fisheries workers being elderly, there's a pressing need to address labor shortages. Consequently, active research on smart aquaculture technologies, centered on object detection and tracking algorithms, is underway. These technologies allow for fish size analysis and behavior pattern forecasting, facilitating the development of real-time monitoring and automated systems. Our study utilized video data from cameras outside aquaculture facilities and implemented fish detection and tracking algorithms. We aimed to tackle high maintenance costs due to underwater conditions and camera corrosion from ammonia and pH levels. We evaluated the performance of a real-time system using YOLOv7 for fish detection and the SORT algorithm for movement tracking. YOLOv7 results demonstrated a trade-off between Recall and Precision, minimizing false detections from lighting, water currents, and shadows. Effective tracking was ascertained through re-identification. This research holds promise for enhancing smart aquaculture's operational efficiency and improving fishery facility management.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• 제23권4호
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• pp.37-53
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• 2024

This study selected bicycle road hazard detection factors for mobile IoT sensor device operation and developed service application plans. Twelve bicycle road hazard detection factors were derived through a focused group interview, and a fuzzy AHP-based importance analysis was conducted on 30 road and transportation experts. As a result, 'damage to pavement' (1st overall) and 'environmental obstacle' (2nd) with low visibility but a high risk of accidents were selected the most. The factors in terms of facility management, such as 'disconnected route occurrence' (4th), 'artificial obstacle' (5th), 'effective width' (6th), and 'poor drainage' (7th), were selected as the upper and middle areas. Factors that are not direct accident-inducing factors, such as 'loss of road markings' (11th) and 'free space width' (12th), were selected the least. Based on this, a plan was presented to apply the bicycle road hazard detection service and a service operation strategy according to real-time performance. Nevertheless, follow-up studies, such as human behavioral analysis based on bicycle operators, analysis according to the bicycle road type, service demonstration, and pilot operation, will be needed to develop safe bicycle road management is expected.