• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2949-2957
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• 2020

Fatigue crack growth model has been developed for dissimilar metal weld joints of a piping component under cyclic loading, where in the crack is located at the center of the weld in the circumferential direction. The fracture parameter, Stress Intensity Factor (SIF) has been computed by using principle of superposition as K_H + K_M. K_H is evaluated by assuming that, the complete specimen is made of the material containing the notch location. In second stage, the stress field ahead of the crack tip, accounting for the strength mismatch, the applied load and geometry has been characterized to evaluate SIF (K_M). For each incremental crack depth, stress field ahead of the crack tip has been quantified by using J-integral (elastic), mismatch ratio, plastic interaction factor and stress parallel to the crack surface. The associated constants for evaluation of K_M have been computed by using the quantified stress field with respect to the distance from the crack tip. Net SIF (K_H + K_M) computed, has been used for the crack growth analysis and remaining life prediction by Paris crack growth model. To validate the model, SIF and remaining life has been predicted for a pipe made up of (i) SA312 Type 304LN austenitic stainless steel and SA508 Gr. 3 Cl. 1. Low alloy carbon steel (ii) welded SA312 Type 304LN austenitic stainless-steel pipe. From the studies, it is observed that the model could predict the remaining life of DMWJ piping components with a maximum difference of 15% compared to experimental observations.

• Journal of Digital Convergence
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• v.17 no.2
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• pp.339-345
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• 2019

This study explores the Experiential Theory of John Dewey and Donald Norman's definition of user experiences to analyze the new cultural experience of trying on Hanbok among the young generation. In order to find out the demographic characteristics, the survey was conducted online. An in-depth interview was held among six women in their 20's who were randomly selected to obtain diverse consumer's opinions. According to the interview, rather than recognizing the traditional beauty of Hanbok, the interviewers recognized the aesthetic sensibility of modernized Hanbok. In addition, the uniqueness of wearing Hanbok which has become the non-ordinary culture and the desire to share the experience is analyzed through characteristics such as particularity. In order to develop cultural contents that are highly marketable, consistent analyzation and research of the fluctuating desire of customers are essential since users perceive their experience to be special.

• Tunnel and Underground Space
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• v.26 no.2
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• pp.68-86
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• 2016

Understanding the frictional properties of rock discontinuities is crucial to ensure the stability of underground structures. In particular, the frictional behavior at depth depends on the complex interaction among mechanical, hydraulic, thermal and chemical characteristics and their coupled effects. In this study, a series of shear tests were carried out in a triaxial compression chamber to investigate the shearing behavior of saw-cut granite surface and rough shear surface of synthetic rocks. The test results were analyzed using Coulomb's shear strength criterion. The frictional behavior of saw-cut granite surface showed little variation at different confining, water pressures and temperature conditions, however in case of synthetic rocks, the frictional behavior showed different trend depending on normal stress level. In addition, the variation of stiffness and dilation at different testing conditions were analyzed, and the stiffness and dilation showed little variation at different water pressures and temperature conditions.

• Human Ecology Research
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• v.54 no.2
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• pp.141-154
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• 2016

This study examined the nature of multi-cultural families' housing problems living in South Korea. A qualitative research was conducted through in-depth interviews with immigrant women from three Southeast Asian countries. The subjects of this study were 15 married immigrants from the Philippine, Cambodia, and Vietnam living in Seoul. The major findings were as follows: firstly, reciprocity for the in-between person and environment: the preferred to blend into Korean society instead of making a community based on national origin. Secondly, intention to housing: all participants were passive about moving and the Vietnamese and Cambodians placed more importance on the family community than the Filipinas. Thirdly, meaning of housing and interaction: for the most important area in the house, the Vietnamese and Cambodians stated that rooms were for a couple and treated family space more importantly than Filipinas who pursuit personal comfort. Fourthly, housing adaptation process: adapting to climate difference between home countries and Korea was the biggest difficulty. Fifthly, residential satisfaction/dissatisfaction: mostly satisfied with housing facilities; however, they were dissatisfied with the number of rooms and house size due to a necessity for personal space. In conclusion, ideas implied from native country of married immigrants in multicultural families did not change significantly in preference of the current environment. The needs for an ethnic community was not great, because they seemed able to assimilate positively by living with a Korean husband and relatives. Gradual assimilation through a cultural acculturation process can be considered desirable.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.4
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• pp.248-257
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• 2010

Applicability of the MIKE21 model as a real time coupled tide-surge model is examined prior to the application as an inundation model. Though the model domain contains the whole southern coasts of Korean Peninsula, the results of tide simulations show good agreement with the observed values. Moreover, the coupled tide-surge model simulates water levels well, especially near the sites which typhoon MAEMI(0314) struck, such as at Tongyung, Masan and Pusan. In addition, it is confirmed that the interaction between storm surge and tide is notable where the water depth is small and the tidal range is large, which indicates the necessity of coupled model especially at the southwestern coast.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.347-351
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• 2020

A material changes its physical and chemical properties through the interaction with radiation and also the neutrons, which is electronically neutral so that the penetration depth is relatively deeper than that of other radioactive way including alpha or beta ray. Therefore, the radiation damage by neutron irradiation has been intensively investigated for a long time with respect to the safety of nuclear power plants. The damage induced by neutron irradiation begins with the creation of point defects in atomic scale in the unit of picoseconds, and their progress pattern can be characterized by microstructural defects, such as dislocation loops and voids. Their morphological characteristics affect the properties of neutron-irradiated materials, therefore, it is very important to predict the microstructure at a given neutron irradiation condition. This paper briefly reviews the evolution of radiation damage induced by neutron irradiation and introduces a phase-field model that can be widely used in predicting the microstructure evolution of irradiated materials.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.10
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• pp.29-33
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• 2010

UV laser micromachining of metallic materials has been used in microelectronic and other industries. This paper shows on experimental investigation of micromachining of copper using a 355nm UV laser with 50ns pulse duration. A finite element model with high strain rate effect is especially suggested to investigate the phenomena which are only dominated by mechanically pressure impact in disregard of thermally heat transfer. In order to consider the strain rate effect, Cowper-Symonds model was used. To analyze the dynamic deformation during a very short processing time, which is nearly about several tens nanoseconds, a commercial Finite Element Analysis (FEA) code, LS-DYNA 3D, was employed for the computational simulation of the UV laser micro machining behavior for thin copper material. From these computational results, depth of the dent (from one to six pulsed) were observed and compared with previous experimental results. This will help us to understand interaction between UV laser beam and material.

• Korean Journal of Childcare and Education
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• v.9 no.5
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• pp.461-488
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• 2013

This study aimed to explore the meanings of fathers' experiences as they participated in educational programs for fathers. In-depth interviews with 3 fathers with children attending elementary school and middle school were implemented to examine their participation experiences in educational programs for fathers and their expectations for educational programs for fathers. The findings of this study showed that fathers wanted opportunities to carry out more active roles with their children instead of passive father roles. They learned interaction with their children and wives through participating in educational programs. The education programs impart a broader perspective and knowledge of father roles, and participation may encourage improvement of their relationships with their children and wives. They felt the importance of father roles in educational programs, which helps a father be a good father. But, they complained about harsh circumstances to participate in educational programs. So educational programs for fathers should be provided to all fathers that are geared to the level and need of each father. Further studies for more revelatory documentation were also suggested.

• Journal of Advanced Navigation Technology
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• v.25 no.1
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• pp.102-107
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• 2021

In the case of long-term hospitalization for young patients, 'Hospital Schools' are operated to pursue school classes and to develop social and emotional abilities for them. However, face-to-face classes at hospital schools have been completely prohibited, and the untact or limited contact environment has been strengthened even for young patients due to the COVID-19 in recent years. Augmented Reality(AR) technology enables the development of experiential content with virtual environments, objects and characters similar to real life. The developed contents should revitalize the imagination of young patients living only in hospitals and allow them to experience, not only acquiring knowledge, but also improving interpersonal skills and sociality. This study is intended to provide diverse adventures and in-depth choice experiences to young patients who are struggling in an environment of untact and limited contact by creating experiential fairy tale contents using AR technology. In addition, long-term hospitalized children will be able to cultivate the will to overcome illness with positive emotions through the augmented reality experience fairy tale content studied and implemented in this study.

• The Journal of the Korea Contents Association
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• v.22 no.6
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• pp.78-91
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• 2022

The importance of emotional intelligence education in the development of children's augmented reality education content is overlooked. Therefore, in-depth research is needed to develop children's emotional intelligence. This study was conducted through theoretical consideration and case analysis. The proposal of this paper is that the augmented reality type for children aged 2 to 7 is suitable for indoor activities with marking recognition technology. To promote an understanding of emotions, a large screen is selected, and emoticon dolls or emoticon books are recommended for learning content. Children aged 7 to 11 are suitable for indoor activities of non-marker recognition technology, and can induce emotional control and emotional recognition through active manipulation. For the learning content, "3D art teaching content" and "Online Classic Musical" are recommended. Children after the age of 11 are suitable for non-marker recognition technology outdoor activities and improve each element of emotional intelligence through interaction with nature and society. For the learning content, 'Forest Play Activity through Art' and 'EQ Theater Play' are recommended. Through this paper, we intend to promote the development of children's augmented reality emotional intelligence education.