• Nuclear Engineering and Technology
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• v.50 no.8
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• pp.1372-1386
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• 2018

Despite recent advances in multi-hazard analysis, the complexity and inherent nature of such problems make quantification of the landslide effect in a probabilistic safety assessment (PSA) of NPPs challenging. Therefore, in this paper, a practical approach was presented for performing an earthquake-induced landslide PSA for NPPs subject to seismic hazard. To demonstrate the effectiveness of the proposed approach, it was applied to Korean typical NPP in Korea as a numerical example. The assessment result revealed the quantitative probabilistic effects of peripheral slope failure and subsequent run-out effect on the risk of core damage frequency (CDF) of a NPP during the earthquake event. Parametric studies were conducted to demonstrate how parameters for slope, and physical relation between the slope and NPP, changed the CDF risk of the NPP. Finally, based on these results, the effective strategies were suggested to mitigate the CDF risk to the NPP resulting from the vulnerabilities inherent in adjacent slopes. The proposed approach can be expected to provide an effective framework for performing the earthquake-induced landslide PSA and decision support to increase NPP safety.

• Archives of Craniofacial Surgery
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• v.22 no.3
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• pp.131-134
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• 2021

Morbihan disease (MD) is a rare condition that involves rosaceous lymphedema or erythematous lymphedema of the middle and upper thirds of the face. It typically affects the periorbital region, forehead, glabella, nose, and cheeks. The etiology of MD remains unclear, and its diagnosis is challenging. MD often tends to be unresponsive to therapies commonly used to treat rosacea, including corticosteroids, isotretinoin, and antibiotics. Surgical treatments have therefore been attempted, but most cases showed unsatisfactory responses. These problems could have resulted from an incorrect recognition and interpretation of the pathophysiology of MD and inaccurate planning of the operation, resulting in recurrence or exacerbation of edema.

• Electronics and Telecommunications Trends
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• v.36 no.3
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• pp.87-96
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• 2021

Quantum computers will be a game-changer in various fields, such as cryptography and new materials. Quantum computer is quite different from the classical computer by using quantum-mechanical phenomena, such as superposition, entanglement, and interference. The main components of a quantum computer can be divided into quantum-algorithm, quantum-classical control interface, and quantum processor. Universal quantum computing, which can be applied in various industries, is expected to have more than millions of qubits with high enough gate accuracy. Currently, It uses general-purpose electronic equipment, which is placed in a rack, at room temperature to make electronic signals that control qubits. However, implementing a universal quantum computer with a low error rate requires a lot of qubits demands the change of the current control system to be an integrated and miniaturized system that can be operated at low temperatures. In this study, we explore the fundamental units of the control system, describe the problems and alternatives of the current control system, and discuss a future quantum control system.

• Journal of The Korean Astronomical Society
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• v.34 no.4
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• pp.191-201
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• 2001

My contribution to these proceedings summarizes a general overview on High Resolution Shock Capturing methods (HRSC) in the field of relativistic hydrodynamics with special emphasis on Riemann solvers. HRSC techniques achieve highly accurate numerical approximations (formally second order or better) in smooth regions of the flow, and capture the motion of unresolved steep gradients without creating spurious oscillations. In the first part I will show how these techniques have been extended to relativistic hydrodynamics, making it possible to explore some challenging astrophysical scenarios. I will review recent literature concerning the main properties of different special relativistic Riemann solvers, and discuss several 1D and 2D test problems which are commonly used to evaluate the performance of numerical methods in relativistic hydrodynamics. In the second part I will illustrate the use of HRSC methods in several astrophysical applications where special and general relativistic hydrodynamical processes play a crucial role.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.8-12
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• 2022

Water loss is one of the typical but challenging problems in water management. To reduced water loss or increase water efficiency, the pilot projects were implemented in the TTD's irrigation area. Modern soil moisture technology and local level water user training were conducted together as a mean to achieve improved water efficiency. In terms of technology, soil moisture sensors and monitoring system were used to estimate crop water requirement to reduce unnecessary irrigation. This was found to save 16.47% of irrigated water and 25.20% of irrigation supply. Further improvement of water efficiency was gained by means of local level water user training in which stakeholders were engaged in the network of communications and co-planning. The lessons learnt from the TTD pilot project was translated into good water management practices at local level.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.808-813
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• 2022

This study presents the problems of data imbalance, varying difficulties across target objects, and small objects in construction object segmentation for far-field monitoring and utilize compound loss functions to address it. Construction site scenes of assembling scaffolds were analyzed to test the effectiveness of compound loss functions for five construction object classes---workers, hardhats, harnesses, straps, hooks. The challenging problem was mitigated by employing a focal and Jaccard loss terms in the original loss function of LinkNet segmentation model. The findings indicates the importance of the loss function design for model performance on construction site scenes for far-field monitoring.

• Annual Conference of KIPS
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• 2021.11a
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• pp.764-767
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• 2021

While Generative Adversarial Networks (GANs) have seen huge success in image synthesis tasks, synthesizing high-quality images from text descriptions is a challenging problem in computer vision. This paper proposes a method named Text-to-Face Generation Using Multi-Scale Gradients for Conditional Generative Adversarial Networks (T2F-MSGGANs) that combines GANs and a natural language processing model to create human faces has features found in the input text. The proposed method addresses two problems of GANs: model collapse and training instability by investigating how gradients at multiple scales can be used to generate high-resolution images. We show that T2F-MSGGANs converge stably and generate good-quality images.

• Annual Conference of KIPS
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• 2021.11a
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• pp.783-786
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• 2021

In recent years, the use of LiDAR sensors is increasing as autonomous driving, robot control, and drones are considered more. Contrary to ordinary cameras, LiDAR sensors make it possible to handle challenging problems by calculating the distance between objects. This crucial characteristic makes more active research on deep learning models dealing with point clouds which are data of LiDAR. In this paper, among the schemes of using the point cloud, the Point-based approach is mainly discussed. Furthermore, future streams and insights can be considered by looking at solving methods and the limitations.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.32-33
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• 2021

The corrosion of the embedded steel rebars and the consequent deterioration of the reinforced concrete structure has become a challenging concern to the construction industries for the fiscal deficit. However, corrosion inhibitors are potential and being widely used for corrosion mitigation to solve such problems. This study has been focused on the mixed type of corrosion inhibitor where one component of the corrosion inhibitor is organic and another one is inorganic material. 0.1 (M) triethanolamine (TEA) and 0.01 (M) sodium hexametaphosphate (SHMP) have been mixed in distilled water to produce the mixed inhibitor. Studies of the steel rebar corrosion in chloride contaminated (3.5 wt.% NaCl) concrete pore (CCCP) solution has been conducted using different concentrations of corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) method is involved to understand the corrosion behaviour of the steel rebars at different exposure durations.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.30-31
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• 2015

PPPs in international development cooperation can be challenging due limited capacities in the country, weaknesses in terms of policy and legislative frameworks, differences in mindsets, values, work ethics and hierarchical structures as well as cultural issues. These can lead to misunderstandings and implementation problems. However, a careful assessment of the situation on the ground, stakeholder analysis and needs assessment can help to identify potential bottlenecks and address capacity constraints that could slowdown operations. A sound understanding of local power dynamics and work practices can help to put in place an exit strategy which will enhance the projects' sustainability. Making sure that goals and objectives are understood in the same way by all partners, establishing an ongoing and respectful dialogue between them, as well as transparent implementation and monitoring mechanisms can also contribute to the PPP's success and increase the likeliness to make a difference in the lives of those in needs.