• Journal of the Korea institute for structural maintenance and inspection
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• 제27권1호
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• pp.9-18
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• 2023

The purpose of this paper is to review the appropriateness of the application method for the value of the damping ratio suggested in the current design standards and evaluation guidelines when evaluating the seismic performance of concrete dams and to suggest improvements. As a result of the study, for the magnitude of the damping ratio in the dynamic elastic analysis, it is necessary to refer to the case of a similar dam in which the magnitude of the earthquake load is similar and the reproducibility of the damping ratio has been verified. Considering this, it is necessary to apply a low damping ratio and consider adding hysteresis damping in case of nonlinear behavior. In addition, since the concrete dam body located on the rock has insignificant radiation attenuation effect, it is not reasonable to increase the damping ratio of the concrete dam body to reflect the radiation damping. Therefore, in order to evaluate the realistic seismic performance of concrete dams, it is necessary to revise the damping ratio-related contents contained in the current dam design standards and evaluation guidelines.

• Geomechanics and Engineering
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• 제31권5호
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• pp.439-452
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• 2022

A forecast of slope behavior during catastrophic events, such as earthquakes is crucial to recognize the risk of slope failure. This paper endeavors to eliminate the significant supposition of predefined slip surfaces in the slope stability analysis, which questions the relevance of simple conventional methods under seismic conditions. To overcome such limitations, a methodology dependent on the slip line hypothesis, which permits an automatic generation of slip surfaces, is embraced to trace the extreme slope face under static and seismic conditions. The effect of earthquakes is considered using the pseudo-static approach. The current outcomes developed from a parametric study endorse a non-linear slope surface as the extreme profile, which is in accordance with the geomorphological aspect of slopes. The proposed methodology is compared with the finite element limit analysis to ensure credibility. Through the design charts obtained from the current investigation, the stability of slopes can be assessed under seismic conditions. It can be observed that the extreme slope profile demands a flat configuration to endure the condition of the limiting equilibrium at a higher level of seismicity. However, a concurrent enhancement in the shear strength of the slope medium suppresses this tendency by offering greater resistance to the seismic inertial forces induced in the medium. Unlike the traditional linear slopes, the extreme slope profiles mostly exhibit a steeper layout over a significant part of the slope height, thus ensuring a more optimized solution to the slope stability problem. Further, the susceptibility of the Longnan slope failure in the Huining-Wudu seismic belt is predicted using the current plasticity approach, which is found to be in close agreement with a case study reported in the literature. Finally, the concept of equivalent single or multi-tiered planar slopes is explored through an example problem, which exhibits the appropriateness of the proposed non-linear slope geometry under actual field conditions.

• Journal of Industrial Convergence
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• 제21권2호
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• pp.103-109
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• 2023

In Korea, software education is implemented from elementary school. As a representative software education tool for elementary schools, various chess games reconstructed based on the rules of Western chess games are being used. On the other hand, Yutnori, one of our traditional games, also includes elements of software education, so research on this is needed. Therefore, in this study, a Yutnori program based on computational thinking using an educational programming language, Entry, and a turtle robot was developed and its validity verified. As a result of the validity verification, the CVR value was higher than 0.7 in the degree of agreement with the subject achievement standard (3 questions), the appropriateness of learning materials (4 questions), and the possibility of class application (3 questions). Therefore, it could be judged that the learning program developed in this study has a high level of agreement with the subject achievement standards, appropriate learning materials, and high possibility of being applied to classes. In order to generalize this content in the future, the effectiveness will need to be verified, and experimental research will be needed to understand this.

• Imaging Science in Dentistry
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• 제53권3호
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• pp.199-207
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• 2023

Purpose: The objective of this study was to evaluate the accuracy and effectiveness of an artificial intelligence (AI) program in identifying dental conditions using panoramic radiographs(PRs), as well as to assess the appropriateness of its treatment recommendations. Materials and Methods: PRs from 100 patients(representing 4497 teeth) with known clinical examination findings were randomly selected from a university database. Three dentomaxillofacial radiologists and the Diagnocat AI software evaluated these PRs. The evaluations were focused on various dental conditions and treatments, including canal filling, caries, cast post and core, dental calculus, fillings, furcation lesions, implants, lack of interproximal tooth contact, open margins, overhangs, periapical lesions, periodontal bone loss, short fillings, voids in root fillings, overfillings, pontics, root fragments, impacted teeth, artificial crowns, missing teeth, and healthy teeth. Results: The AI demonstrated almost perfect agreement (exceeding 0.81) in most of the assessments when compared to the ground truth. The sensitivity was very high (above 0.8) for the evaluation of healthy teeth, artificial crowns, dental calculus, missing teeth, fillings, lack of interproximal contact, periodontal bone loss, and implants. However, the sensitivity was low for the assessment of caries, periapical lesions, pontic voids in the root canal, and overhangs. Conclusion: Despite the limitations of this study, the synthesized data suggest that AI-based decision support systems can serve as a valuable tool in detecting dental conditions, when used with PR for clinical dental applications.

• Journal of Korea Entertainment Industry Association
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• 제13권6호
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• pp.297-306
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• 2019

The purpose of this study was to develop a scale for measuring obsessive compulsive and to verify structural validity from students participating in physical education class. The procedure for this purpose was firstly conducted through an open questionnaire, followed by item search and appropriateness assessment, then analyzing the reliability of the final version based on the preliminary criterion and checking the construct validity. After analyzing the factors of the criticism, We collected the data and analyzed the items and the factors from 387 respondents. The subjects were social obsession (4 items), psychological obsession (3 items) and physical obsession (3 items) The final determinant of the 10 factors was completed. We conducted A multivariate analysis on the determinants of gender and class satisfaction to confirm the external relationship review. The reliability of the scale developed in this study showed not only a high level of confidence from .856 to .907, but also reasonized and proved to be an obsessional scale for physical education for the promotion of life care. These measures can be used as a data for measuring physical education compulsion in class.

• (The) Research of the performance art and culture
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• 제43호
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• pp.405-440
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• 2021

The members of the holding group 'YangjuByeolsandae-nori' (National Important Intangible Cultural Heritage) were divided into two groups in 2010. This means that the internal groupwhich has been going on since the previous period exploded. The subject of the researchis to deal with thedisruption. The first purpose of the research is to record the cause·deployment·ending of the 'YangjuByeolsandaeTalnori'. The second purpose of the research is to reviewthe appropriateness of the administrative measures taken by the Cultural Heritage Administrationin intervention. The thirdpurpose of the research the Cultural Heritage Administration's contribution to the establishment of principles to cope with group disruption. The fourth purpose of the researchis to serve as a reference to the resolution of the disruption of other preservation groups. The result of the research suggests that the administration should recognize that the conflict of the ownership over the group must be resolved in order to boost the overall success of the project, and must establish and respond to the principles. The content is a reconstruction of the explanation. To deal with divisions is also considered to be a field of study. The research which deals directly with the main researcher's problems is put forward in hopes of contributing to the study and contributing to society.

• Journal of the Korean Geotechnical Society
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• 제25권10호
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• pp.41-53
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• 2009

In order to analyze the influence of particle shape on evolution of particle crushing and characteristic of shear behavior of granular soil, direct shear test was simulated by using DEM (Discrete Element Method). Six particle shapes were generated by clump and cluster model built in PFC (Particle Flow Code). The results of direct shear test for six particle shapes were compared and analyzed with those for circular particle shape. The results of numerical tests showed a good agreement with those of experimental tests, thus the appropriateness of numerical modelling set in this study was proved. As for particle shape, more angular and rougher particle induced larger internal friction angle and more particle crushing than relatively round and smooth particle. When particles were crushed, crushing was concentrated on the shear band adjacent to the shear plane. Finally, it can be concluded that the numerical models suggested in this study can be used extensively for other studies concerning the shear behavior of granular soil including soil crushing.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제28권3A호
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• pp.407-415
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• 2008

Hydration reaction of Free-CaO is thought to be the main reason of expansion failure of slag. A lot of research institutions are conducting studies on solutions to this problem, and moreover it has been carried out how to make use of aggregates for concrete. While studies covering wide rage of blast furnace slag have been accomplished in the country, studies on steelmaking slag are insufficient. Therefore, this study aimed at analyzing basic physical properties of electric arc furnace oxidizing slag, which is the main material, and furthermore it focused on how to make use of aggregates for concrete examining chemical mechanism, which can be put to practical use. To address this issue, components of electric arc furnace oxidizing slag were analyzed with measurement of physical properties, followed by long-term strength and detailed durability analysis, which can evaluate the appropriateness of application of cement concrete. Besides the environmental conservation and recycling which can be obtained by application of industry byproducts, commercializing of electric arc furnace oxidizing slag as fine aggregates for cement concrete are expected.

• KSCE Journal of Civil and Environmental Engineering Research
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• 제30권4D호
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• pp.403-411
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• 2010

Nowadays, Light railway system is attracted public attention as solution for metropolitan traffic congestion. But it is difficult to decide an appropriate light railway system. It is especially hard in the Seoul metropolitan to decide an appropriate system, because there are many factors that must considered. So we research application status of light railway system that is scheduled or promoted in the Korea and the foreign nations. And we selected systems by types of city. In this paper, we divided into 6 types of city through factor analysis and cluster. And we considered various factor such as technology, transportation, environment etc that used previous research and feasibility study. To determine the priority among the factors, AHP(Analytic Hierarchy Process) was applied as a method for multi-standard decision method.

• The Journal of Sustainable Design and Educational Environment Research
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• 제22권3호
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• pp.14-29
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• 2023

This study aims to elucidate the content and format of school safety standards to clarify the roles and responsibilities of schools in realizing school safety. Toward this end, difficulties in operating school safety standards at various sites were classified into four small groups with a total of 26 educational administrators, superintendents, and researchers to listen to the opinions of experts in the field and analyze related data. As a result, we comprehensively analyzed in-depth interviews with the respondents who are working at provincial offices of education regarding the proposed school safety standards. We also analyzed the necessity of developing these standards and examining the appropriateness of their content and format. Results were derived from four aspects, including the field applicability of such standards. The study draws the following conclusions. First, it focuses on setting the direction for the development of school safety standards. Second, it highlights the exploration of the system and content of these standards. Third, it pertains to the preparation of a draft of these standards.