• Journal of the Society of Naval Architects of Korea
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• v.57 no.5
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• pp.271-277
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• 2020

Recoverability and vulnerability of navy ships under underwater explosion are critical verification factors in the acquisition phase of navy ships. This paper aims to establish numerical analysis techniques for the underwater explosion of navy ships. Doubly Asymptotic Approach (DAA) Equation of Motion (EOM) of primary shock wave and secondary bubble pulse proposed by Geers-Hunter was introduced. Assuming a non-compressive fluid, reference solution of the DAA EOM of Geers-Hunter using Runge-Kutta method was derived for the secondary bubble pulse phase with an assumed charge conditions. Convergence analyses to determine fluid element size were performed, suggesting that the minimum fluid element size for underwater explosion analysis was 0.1 m. The spherical and cylindrical fluid domains were found to be appropriate for the underwater explosion analyses from the fluid domain shape study. Because the element size of 0.1 m was too small to be applied to the actual navy ships, a very slender beam with the square solid section was selected for the study of fluid domain existence effect. The two underwater explosion models with/without fluid domain provided very similar results in terms of the displacement and stress processes.

• Journal of Internet of Things and Convergence
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• v.7 no.1
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• pp.27-34
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• 2021

Modern society is rapidly developing into the Internet of Things and Big Data, and there are industries that develop even in the Corona era. However, the church is not developing and responding enough to the Corona era, and it is shaking the existence of the church itself. The essence of the church consists of worship, evangelism, education, service, and companionship. In the era of Corona, where non-face-to-face safety is important, the essence does not change, but efforts to embody the essence of the church in a socially responsible manner are needed. This paper discusses the social responsibility of the church in this respect, focusing on the five essential elements of the church. To this end, we examine the essential elements of the church and study the implementation methods suitable for the Corona era.

• Journal of Contemporary Eastern Asia
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• v.20 no.1
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• pp.102-119
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• 2021

Social credit rating in China (SCRC) has been criticized as "dystopian" and "Orwellian," an attempt by the Communist Party to hold onto power by exerting ever greater control over its citizens. To explain such measures, value differences are often invoked, that Chinese value stability and cooperation over privacy and freedom. However, these explanations are oversimplifications that result in ethical impasses. This article argues social credit rating should be understood in terms of the commonly human problem of large-scale cooperation. To do so, this paper relies on a cultural evolutionary framework and is an exercise in interpretive pros hen ethical pluralism, attempting to understand how apparently irresolvable cultural differences stem from common human concerns. Wholesale condemnation of SCRC fails to acknowledge the serious, intractable nature of problems resulting from a lack of trust in China. They take for granted the existence of institutions ensuring largescale, anonymous cooperation characteristic of - but somewhat unique to - Western Educated Industrialized Rich and Democratic (WEIRD) cultures. Because of its history and rapid development, China lacks the institutions necessary to ensure such cooperation, and because of anti-social punishment, social credit rating might be one of the few ways to ensure cooperation at this scale. The point is not to defend social credit rating in general, but to raise the possibility of its defense in China and show one way this would be done.

• The Journal of Asian Finance, Economics and Business
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• v.10 no.2
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• pp.267-280
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• 2023

The relationship between the state and taxation starts from the establishment of the state. The most important element is the concept of "tax compliance". Tax compliance can be considered as the harmony of state-society relations. However, the concept of tax non-compliance occurs when taxpayers do not fulfill their tax-related tasks as required. Tax noncompliance is just one of the costs that occur in tax systems, and is named "tax compliance cost" in the literature. This study focuses on tax compliance costs because tax compliance costs are the ones taxpayers are personally obliged to deal with. For this purpose, the study investigates costs accruing from tax systems, including efficiency, planning, application, and compliance costs. According to the analysis results, it was concluded that the main reason for fraud in the tax systems is high compliance costs and that tax compliance directly impacts social wealth. Besides, the existence of conditions conducive to tax evasion and tax avoidance in a country, short-term tax policies, belief in the unfairness and inequality of tax systems, inadequacy of audits conducted by tax authorities, insufficiency of pressure and deterrence mechanisms, constantly changing legislation, and the attitudes and perceptions regarding the illegitimacy of the government determine tax compliance.

• Smart Structures and Systems
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• v.29 no.1
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• pp.221-235
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• 2022

Manual inspection of steel box girders on long span bridges is time-consuming and labor-intensive. The quality of inspection relies on the subjective judgements of the inspectors. This study proposes an automated approach to detect and segment cracks in high-resolution images. An end-to-end cascaded framework is proposed to first detect the existence of cracks using a deep convolutional neural network (CNN) and then segment the crack using a modified U-Net encoder-decoder architecture. A Naïve Bayes data fusion scheme is proposed to reduce the false positives and false negatives effectively. To generate the binary crack mask, first, the original images are divided into 448 × 448 overlapping image patches where these image patches are classified as cracks versus non-cracks using a deep CNN. Next, a modified U-Net is trained from scratch using only the crack patches for segmentation. A customized loss function that consists of binary cross entropy loss and the Dice loss is introduced to enhance the segmentation performance. Additionally, a Naïve Bayes fusion strategy is employed to integrate the crack score maps from different overlapping crack patches and to decide whether a pixel is crack or not. Comprehensive experiments have demonstrated that the proposed approach achieves an 81.71% mean intersection over union (mIoU) score across 5 different training/test splits, which is 7.29% higher than the baseline reference implemented with the original U-Net.

• International Journal of Advanced Culture Technology
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• v.10 no.2
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• pp.86-91
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• 2022

The purpose of this study is to study the tragic world perception that appears in Kim Sung-han's novels 'Frogs' and 'Five Minutes'. The main emotion that emerges in his novels in the 1950s is non-polarity. His novels "Frogs" and "Five Minutes" satirically express the relationship between God and humans, and the human figure in comparison to animals In the 1950s, in Korean society, individual lives were distorted in postwar situations, and the relationship between individuals and society was inconsistent. Kim Sung-han wanted to create new ethical and social values through novels. In "Five Minutes" and "Frog," Kim Sung-han expresses and criticizes the crisis in Korea's post-war society as a tragic reality that God has no ability. In the novel, Kim Sung-han criticizes the degenerate reality of humans without God and criticizes the slave grit of humans who cling to God. After all, what he wants to say in the novel is the perception of human free will and existence. In the two novels, the author talks about a tragic world perception that denies the realm of God, but finds out that there is no other world to live a new life that denies God.

• Smart Structures and Systems
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• v.30 no.4
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• pp.385-395
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• 2022

Detecting cracks on a concrete structure is crucial for structural maintenance, a crack being an indicator of possible damage. Conventional crack detection methods which include visual inspection and non-destructive equipment, are typically limited to a small region and require time-consuming processes. Recently, to reduce the human intervention in the inspections, various researchers have sought computer vision-based crack analyses: One class is filter-based methods, which effectively transforms the image to detect crack edges. The other class is using deep-learning algorithms. For example, convolutional neural networks have shown high precision in identifying cracks in an image. However, when the objective is to classify not only the existence of crack but also the types of cracks, only a few studies have been reported, limiting their practical use. Thus, the presented study develops an image processing procedure that detects cracks and classifies crack types; whether the image contains a crazing-type, single crack, or multiple cracks. The properties and steps in the algorithm have been developed using field-obtained images. Subsequently, the algorithm is validated from additional 227 images obtained from an open database. For test datasets, the proposed algorithm showed accuracy of 92.8% in average. In summary, the developed algorithm can precisely classify crazing-type images, while some single crack images may misclassify into multiple cracks, yielding conservative results. As a result, the successful results of the presented study show potentials of using vision-based technologies for providing crack information with reduced human intervention.

• Journal of applied mathematics & informatics
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• v.41 no.3
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• pp.511-524
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• 2023

An L(p₁, p₂, p₃, . . . , p_m)-labeling of a graph G is an assignment of non-negative integers, called as labels, to the vertices such that the vertices at distance i should have at least pi as their label difference. If p₁ = 4, p₂ = 3, p₃ = 2, p₄ = 1, then it is called a L(4, 3, 2, 1)-labeling which is widely studied in the literature. A L(4, 3, 2, 1)-path coloring of graphs, is a labeling g : V (G) → Z⁺ such that there exists at least one path P between every pair of vertices in which the labeling restricted to this path is a L(4, 3, 2, 1)-labeling. This concept was defined and results for some simple graphs were obtained by the same authors in an earlier article. In this article, we study the concept of L(4, 3, 2, 1)-path coloring for complete bipartite graphs, 2-edge connected split graph, Cartesian product and join of two graphs and prove an existence theorem for the same.

• Communications for Statistical Applications and Methods
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• v.29 no.2
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• pp.251-261
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• 2022

As AI has a wide range of influence on human social life, issues of transparency and ethics of AI are emerging. In particular, it is widely known that due to the existence of historical bias in data against ethics or regulatory frameworks for fairness, trained AI models based on such biased data could also impose bias or unfairness against a certain sensitive group (e.g., non-white, women). Demographic disparities due to AI, which refer to socially unacceptable bias that an AI model favors certain groups (e.g., white, men) over other groups (e.g., black, women), have been observed frequently in many applications of AI and many studies have been done recently to develop AI algorithms which remove or alleviate such demographic disparities in trained AI models. In this paper, we consider a problem of using the information in the sensitive variable for fair prediction when using the sensitive variable as a part of input variables is prohibitive by laws or regulations to avoid unfairness. As a way of reflecting the information in the sensitive variable to prediction, we consider a two-stage procedure. First, the sensitive variable is fully included in the learning phase to have a prediction model depending on the sensitive variable, and then an imputed sensitive variable is used in the prediction phase. The aim of this paper is to evaluate this procedure by analyzing several benchmark datasets. We illustrate that using an imputed sensitive variable is helpful to improve prediction accuracies without hampering the degree of fairness much.

• The Korean Journal of Physiology and Pharmacology
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• v.27 no.2
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• pp.187-196
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• 2023

Transient receptor potential canonical (TRPC) channels are non-selective calcium-permeable cation channels. It is suggested that TRPC4β is regulated by phospholipase C (PLC) signaling and is especially maintained by phosphatidylinositol 4,5-bisphosphate (PIP₂). In this study, we present the regulation mechanism of the TRPC4 channel with PIP₂ hydrolysis which is mediated by a channel-bound PLCδ1 but not by the G_qPCR signaling pathway. Our electrophysiological recordings demonstrate that the Ca²⁺ via an open TRPC4 channel activates PLCδ1 in the physiological range, and it causes the decrease of current amplitude. The existence of PLCδ1 accelerated PIP₂ depletion when the channel was activated by an agonist. Interestingly, PLCδ1 mutants which have lost the ability to regulate PIP₂ level failed to reduce the TRPC4 current amplitude. Our results demonstrate that TRPC4 self-regulates its activity by allowing Ca²⁺ ions into the cell and promoting the PIP₂ hydrolyzing activity of PLCδ1.