• Korean Journal of Remote Sensing
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• v.39 no.5_1
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• pp.621-635
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• 2023

The assessment of structural condition is a crucial process for evaluating its usability and determining the diagnostic cycle. The currently employed manpower-based methods suffer from issues related to safety, efficiency, and objectivity. To address these concerns, research based on deep learning using images is being conducted. However, acquiring structural damage data is challenging, making it difficult to construct a substantial amount of training data, thus limiting the effectiveness of deep learning-based condition assessment. In this study, we propose a foundation model-based 2-step structural damage analysis to overcome the lack of training data in image-based structural condition assessments. We subdivided the elements of structural condition assessment into instantiation and quantification. In the quantification step, we applied a foundation model for image segmentation. Our method demonstrated a 10%-point increase in mean intersection over union compared to conventional image segmentation techniques, with a notable 40%-point improvement in the case of rebar exposure. We anticipate that our proposed approach will enhance performance in domains where acquiring training data is challenging.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.1
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• pp.97-111
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• 2024

Developing countries and small local governments face financial constraints, limiting the adoption of their own bus information systems. However, despite poor social infrastructure and low income levels, developing countries have a high smartphone penetration rate, and the distribution and usage of online content and social media are widespread. Smartphones, equipped with GPS sensors, cameras, and other location-based information collection capabilities, can replace expensive on-site terminals. This study aims to replace expensive on-site terminals with smartphones, develop a center system based on cloud servers, and establish an extensible Open BIS (Bus Information System) service and platform that can be applied anywhere. The goal is to formulate a business model in the process.

• Convergence Security Journal
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• v.24 no.2
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• pp.133-140
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• 2024

The spread of Direct-to-Consumer (DTC) genetic testing, where users request tests directly, has been increasing. With growing demand, certification systems have been implemented to grant testing qualifications to non-medical institutions, and the scope of tests has been expanded. However, unlike cases in less regulated foreign countries, disease-related tests are still excluded from the domestic regulations. The existing de-identification method does not adequately ensure the uniqueness and familial sharing of genomic information, limiting its practical utility. Therefore, this study proposes the application of fully homomorphic encryption in the analysis process to guarantee the usefulness of genomic information while minimizing the risk of leakage. Additionally, to safeguard the individual's right to self-determination, a privacy preservation model based on Opt-out is suggested. This aims to balance genomic information protection with maintainability of usability, ensuring the availability of information in line with the user's preferences.

• Journal of the Korean Society of Radiology
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• v.82 no.3
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• pp.541-550
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• 2021

The below-the-knee arterial tree is the thinnest of all the leg vessels and is an important path for blood flow to the foot. Hence, lesions including stenosis, especially obstruction, may lead to critical limb ischemia which represents the most severe clinical manifestation of peripheral arterial disease. It is characterized by the presence of ischemic rest pain, ischemic lesions, or gangrene attributable to the objectively proven arterial occlusive disease. Typically, the atherosclerotic disease process involving the below-the-knee arterial tree is diffuse in the majority of patients. The cornerstone of therapy is vascular reconstruction and limb salvage. Revascularization should be attempted whenever technically possible, without delay, in patients presenting critical limb ischemia and when the clinical status is not hopelessly non-ambulatory. Therefore, endovascular treatment can become the gold standard for the full range of patients including below-the-knee, limiting the clinical role of the classically trained surgeons.

• Journal of Wind Energy
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• v.14 no.4
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• pp.50-56
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• 2023

With the abnormal weather phenomena caused by global warming, the frequency and intensity of lightning strikes are increasing, and lightning accidents are becoming one of the biggest causes of failures and accidents in offshore wind turbines. In order to secure generator operation reliability, effective and practical measures are needed to reduce lightning damage. Because offshore wind turbines are tall structures installed at sea, the possibility of direct lightning strikes is very high compared to other structures, and the role of surge protection devices to minimize damage to the electrical and electronic circuits inside the wind turbine is very important. In this study, a varistor, which is a key element for a class 1 surge protection device for direct lightning protection, was developed. The current density was improved by changing the varistor composition, and the distance between the electrode located on the varistor surface and the edge of the varistor was optimized through a simulation program to improve the fabrication process. Considering the combined effects of heat distribution, electric field distribution, and current density on the optimized varistor surface, silver electrodes were formed with a gap of 0.5 mm. The varistor developed in this study was confirmed to have an energy tolerance of 10/350 ㎲, 50kA, which is a representative direct lightning current waveform, and good protection characteristics with a limiting voltage of 2 kV or less.

• Composites Research
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• v.37 no.3
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• pp.226-231
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• 2024

Coal ash has been used as a sand replacement in the construction industry. Due to the use of bituminous coal as a result of anthracite depletion, and quicklime as an air purifier in the desulfurization process, pop-out defects have recently occurred in concrete using coal ash, severely limiting the recycling of coal ash into concrete. In this study, the components that cause the pop-out problem of the coal ash filled concrete were identified and a pretreatment method to fully expand the expansive components in advance was proposed as a solution to this problem. By treating water twice for 10 min, allowing the CaO mixed in the coal ash to fully expand, the problems of pop-out and reduced compressive strength of the concrete were overcome. The cost and time efficient water treatment method proposed in this study is expected to promote the recycling of coal ash into concrete.

• Korean Circulation Journal
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• v.54 no.6
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• pp.295-310
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• 2024

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 has led to a global health crisis with substantial mortality and morbidity. To combat the COVID-19 pandemic, various vaccines have been developed, but unexpected serious adverse events including vaccine-induced thrombotic thrombocytopenia, carditis, and thromboembolic events have been reported and became a huddle for COVID-19 vaccination. Vaccine-related myocarditis (VRM) is a rare but significant adverse event associated primarily with mRNA vaccines. This review explores the incidence, risk factors, clinical presentation, pathogenesis, management strategies, and outcomes associated with VRM. The incidence of VRM is notably higher in male adolescents and young adults, especially after the second dose of mRNA vaccines. The pathogenesis appears to involve an immune-mediated process, but the precise mechanism remains mostly unknown so far. Most studies have suggested that VRM is mild and self-limiting, and responds well to conventional treatment. However, a recent nationwide study in Korea warns that severe cases, including fulminant myocarditis or death, are not uncommon in patients with COVID-19 VRM. The long-term cardiovascular consequences of VRM have not been well understood and warrant further investigation. This review also briefly addresses the critical balance between the substantial benefits of COVID-19 vaccination and the rare risks of VRM in the coming endemic era. It emphasizes the need for continued surveillance, research to understand the underlying mechanisms, and strategies to mitigate risk. Filling these knowledge gaps would be vital to refining vaccination recommendations and improving patient care in the evolving COVID-19 pandemic landscape.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1584-1602
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• 2024

It is vital to output the required electrical power following various task requirements when the space reactor power supply is operating in orbit. The dynamic performance of the closed Brayton cycle thermoelectric conversion system is initially studied and analyzed. Based on this, a load tracking power regulation method is developed for the liquid metal cooled space reactor power system, which takes into account the inlet temperature of the lithium on the hot side of the intermediate heat exchanger, the filling quantity of helium and xenon, and the input amount of the heat pipe radiator module. After comparing several methods, a power regulation method with fast response speed and strong system stability is obtained. Under various changes in power output, the dynamic response characteristics of the ultra-small liquid metal lithium-cooled space reactor concept scheme are analyzed. The transient operation process of 70 % load power shows that core power variation is within 30 % and core coolant temperature can operate at the set safety temperature. The second loop's helium-xenon working fluid has a 65K temperature change range and a 25 % filling quantity. The lithium at the radiator loop outlet changes by less than ±7 K, and the system's main key parameters change as expected, indicating safety. The core system uses less power during 30 % load power transient operation. According to the response characteristics of various system parameters, under low power operation conditions, the lithium working fluid temperature of the radiator circuit and the high-temperature heat pipe operation temperature are limiting conditions for low-power operation, and multiple system parameters must be coordinated to ensure that the radiator system does not condense the lithium working fluid and the heat pipe.

• The Korean Journal of Applied Statistics
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• v.37 no.4
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• pp.445-453
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• 2024

For Markov processes whose stationary probabilities are difficult to obtain in the analytical form, approximate solutions can be considered using numerical methods such as a matrix operation method or an iterative calculation method. In this paper we perform the study to verify the accuracy of a numerical iteration formula which calculate the stationary probabilities of Markov chains or processes. Especially, the convergence and accuracy of the numerical method are investigated by using Markov models for system availability. We compare the values of the system availability based on the numerical calculation and those based on the complicated but analytical solutions. We also calculate the iteration numbers necessary for the convergence of the numerical solutions. The accuracy and usefulness of the numerical iterative calculation method can be ascertained through this study.

• Journal of Christian Education in Korea
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• v.63
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• pp.317-345
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• 2020

The dissolution and reconstruction of the male-centered social structure is being requested, but the Korean church still call on women and understand women's roles by limiting them based on traditional 'normal family ideology' and matherhood discourse. However, considering women's various aspects of life, life cycle, and individuality, confining women to existing biological maternal discourse is not suitable to help women grow as subjective leaders and contribute to society. The Korean church needs to find a new curriculum that encourages women to form subjective beliefs. In the life of Christian women of the period of port-opening, we can examine the process of the Korean Christian women establishing the subjectivity of the challenges of Protestant theology, which included stereotypes, gender division of labor, and matherhood discourse. Korean Christian women shared the oppressive experiences of traditional patriarchy after passing silent and receptive perceptions, forming a subjective perception of their injustice and seeking liberation. And it was able to act as a subject of faith by forming a procedural and constructive awareness within a sympathetic and relational community. The Korean church should reconstruct the Christian women's curriculum by reflecting on the curriculum that women formed themselves over 100 years ago.