• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.4
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• pp.489-496
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• 2019

This paper is a study on the evaluation of loss factor of damping treatment materials to reduce the noise and vibration for panels of railway vehicles and automobiles. In order to determine the modal parameters of damping materials, beam excitation tests were carried out using different type PVC coated aluminum and steel base beam specimens. The specimens were excited from 10 Hz to 1000 Hz frequency range using sinusoidal force, and transfer mobility data were measured by using an accelerometer. The loss factors were determined by using integrated program, based on theories of Half Power Method, Minimum Tangent Error Method, Minimum Angle Error Method and Phase Change Method, which enable to evaluate the parameters using modal circle fit and least squares error method. In the case of lower loss factor and data of linear characteristics, any method could be applied for evaluation of parameters, however the case of higher loss factor or data including non-linear characteristics, the minimum angle error method could reduce the loss factor evaluation. The obtained dynamic properties of the coating material could be used for application of Finite Element Method analyzing the noise control effects of complex structures such as carbody or under-floor boxes of rolling stock. The damping material will be very useful to control the structural noise, because the obtained modal loss factors of each mode show very good effect on over $2^{nd}$ mode frequency range.

• Journal of the Korean GEO-environmental Society
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• v.20 no.1
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• pp.67-74
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• 2019

Frost heave is one of the representative engineering characteristics in cold regions. In South Korea, which is located in seasonal frost area, structural damage caused by frost heave and thaw happens and the need for research on the frost heave is increasing. In this paper, newly developed transparent temperature-controllable cell is used to focus on the frost heave. Frost susceptible artificial soil is used to analyze water intake rate which is one of the important factors in frost susceptibility criteria. Frost heave rate and water intake rate have similar behavior after heave by freezing of pore water converges. O-ring installed in the upper pedestal to measure water intake rate generates side friction between the inner wall of the freezing cell and O-ring, thereby hindering frost heave. Therefore, the frost susceptibility criteria using the water intake rate is not reliable. It is appropriate to use frost heave rate which has similar behavior with water intake rate. Frost heave tests were performed under two different specimen heights. Overburden pressure, temperature gradient and dry unit weight were set under similar state. Based on laboratory testing results, frost heave is independent on the specimen height.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.13-19
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• 2019

After the Fukushima nuclear accident, a new power supply using a lithium polymer battery has been proposed the first time in the world as the safety of the emergency battery facility has been required. It is required to have the safety of the rack system in which the battery device is installed in order to apply the proposed technology to the field. Therefore, the purpose of this study is to evaluate the seismic performance of string and rack frame for lithium-polymer battery devices developed for the first time in the world to satisfy 72 hours capacity. (1) The natural frequency of the unit rack system was 9 Hz, and the natural frequency before and after the earthquake load did not change. This means that the connection between members is secured against the design earthquake load. (2) he vibration reduction effect by string design was about 20%. (3) As a result of the seismic performance test under OBE and SSE conditions, the rack frame system was confirmed to be safe. Therefore, the proposed rack system can be applied to the nuclear power plant because the rack system has been verified structural safety to the required seismic forces.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.485-496
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• 2019

The current study examined the latent mean analysis and path analysis comparison between male and female groups in the structural relationships among parent-child conversation, peer attachment, satisfaction in teacher at a community child care center, ego-resiliency, self-esteem, and career identity in adolescents who attend a community child care center. For this purpose, 438 adolescents who participated in the 4th(2017) questionnaire in the 2nd child panel of the community child care center were used. From the analysis results, first, peer attachment and satisfaction in teacher at a community child care center increased ego-resiliency and career identity, but parent-child conversation did not predict ego-resiliency and career identity. Peer attachment and satisfaction in teacher at a community child care center was fully mediated by ego-resiliency and self-esteem to career identity. Second, in the latent mean analysis, male students showed significantly higher latent mean values in ego-resiliency and self-esteem than female students, while female students showed significantly higher latent mean values in parent-child conversation than male students. Third, multi-group analysis revealed different paths to career identity between the genders. Peer attachment can buffer the effect of ego-resiliency and self-esteem on career identity of male students, but satisfaction in teacher at a community child care center buffers more on the ego-resiliency of female students. The results of this study suggest that social support for enhancing ego-resiliency and self-esteem is needed to encourage career identity, and that gender needs to be considered.

• Management & Information Systems Review
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• v.37 no.4
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• pp.257-270
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• 2018

Although healing is now developing an interest in extending tourism, there have been few studies in this area. Especially late-night tour is closely related to healing experience, but there are little researches that help us understand healing in late-night tour. This study was conducted to examine the relationships among late-night scapes(light aesthetics, sharing mood, culture uniqueness), healing experience(stress reduce and psychological happiness), attitude toward late-night tour. We collected data involving various late-night tourist, and used 198 respondents to analyze these data using LISREL structural modeling. Light aesthetics and sharing mood had positive effects on stress remove, but Culture uniqueness didn't have a signigicant effect on stress remove, unlikely the prediction. And all late-night shape had positive effects on psychological happiness. Also we tested the effects of the healing experience(stress remove and psychological happiness) on attitude. In the final section, we discussed several limitations of our study and suggested directions for future research. We concluded with a discussion of managerial implications, including the potential to advance understanding late-night tourist and implying an enhanced ability to satisfy target consumers of late-night tour.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.2
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• pp.93-106
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• 2021

In general, segment lining tunnel refers to a tunnel formed by connecting precast concrete segments as a ring and connecting such rings to each other in the longitudinal direction of the tunnel. As the structural properties of the segment lining is highly dependent on the behavior of the segment joints, thus correct modelling of joint behavior is crucial to understand and design the segment tunnel lining. When the tunnel is subjected to ground loads, the segment joint behaves like a hinge that resists rotation, and when the induced moment exceeds a certain limit of the rotation then it may enter into non-linear field. In understanding the effect of the segment joint on the lining behavior, a moment-rotation relationship of the segment joint was explored based on the Japanese practice and Janssen's approach commonly used in the actual design. This study also presents a method to determine the rotational stiffness of joint refer to the bearing strength. The rotation of the segment joint was estimated in virtual design conditions based on the existing models and the proposed method. And the sectional force of the segment lining and joint were calculated along with the estimated rotation. As the rotation at the segment joint increases, the joint contact area decreases, so the designer have to verify the segment joint for bearing strength as well. This paper suggests a consistent method to determine the rotational stiffness and bearing strength of joints.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.3
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• pp.258-273
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• 2019

Bilbao, Spain, made a mark as a example of the regional revitalization by culture and tourism. Korean Government have a perspective that culture and tourism could be an alternative to the regional crisis of manufacturing in 2018. The main purpose of this study is to analyze the locational specificity and the revival strategies for the regional development of Bilbao in a structural context. This could provide implications to the regional crisis of Korea. The main results are summarized as follows. Firstly, the local government of Bilbao has taken an active role, using not only its political and financial autonomy but also its locational advantage as an important nodal region of transnational trade networks in Europe. Secondly, Bilbao was able to sustain its regional revitalization initiatives for a long period by facilitating public-private partnership system. Finally, despite the effectiveness of the mega project and place marketing, low job security and the polarization of the service sector have emerged as a problem at the same time. Still, the deindustrialization of Bilbao could be possible due to the various services including knowledge-based services and financial services as well as culture and tourism.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.159-170
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• 2021

As the main purpose of R&D changes from the center of knowledge creation to the center of economic value creation through technology transfer and commercialization, public technologies can also secure economic feasibility as well as make a social contribution. Korea has been focusing on fostering core human resources who can lead the commercialization of basic and original research results by launching the 'Support project for exploring startups linked with public technology-based markets' since 2015 in order to promote public technology startup. This study is based on the results of a survey for the purpose of analyzing the performance of this project. In addition, this study derived four factors related to the I-corps project performance from the results of this survey and verified the relationship between these factors through structural equation model analysis. In summary, it was confirmed that 'Application Level' and 'Business Model,' which are positively affected directly from 'Entrepreneurship Learning,' have positive effects on 'Financial Resources'. Furthermore, the indirect effect of 'Entrepreneurship Learning' on 'Financial Resources' was verified. In particular, the high level of impact of 'Entrepreneurship Learning' on 'Application Level,' and the impact of 'Application Level' on 'Business Model' and 'Financial Resources' were also positive.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.133-137
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• 2011

In this study, illite was size-reduced using a wet-ball-milling treatment to improve its dispersion. Changes in illite particle size, size distribution, and dispersion characteristics after varying the treatment period were investigated. And the dispersion and dispersion stability of illite solution after 2 h wet ball milling treatment with different pH conditions were also evaluated. The illite particle size significantly decreased as the treatment time increased and the size reduction effect of wet ball milling deteriorated above 2 h treatment time. In addition, illite particle size was more evenly distributed as the treatment time increased. X-ray diffraction (XRD) analysis showed that no crystal structural changes of illite were induced, but the characteristic peak of illite the weaker due to the size reduction and exfoliation, as the treatment time increased. Zeta potential analysis showed that the illite dispersion improved, as the treatment time increased. The illite wet-ball-mill treated at pH 2 had the lowest dispersion stability. Illite dispersion and dispersion stability increased as pH increased, due to the increase in surface ionization. Hence, the results showed that as the treatment time increased, the illite particle size decreased, and dispersion and dispersion stability improved due to the increase in surface energy and repulsion force between particles.

• Korean journal of psychology:General
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• v.36 no.2
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• pp.241-270
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• 2017

In this study we investigated the structural relationship between the Big Five personality traits which is a pretrauma characteristic, posttraumatic cognition, rumination, posttraumatic growth(PTG), and posttraumatic stress disorder(PTSD) symptoms. The participants were 1,000 adults who experienced traumatic event. For statistical analysis we set the research model with the Big Five personality traits affecting deliberate rumination through posttraumatic cognition and intrusive rumination. Competing model was set without the path from intrusive rumination to deliberate rumination. The results indicated that rumination and posttraumatic cognition did not mediate the relationship between extraversion, agreeableness, conscientiousness and PTG, PTSD symptoms. Second, there was a mediating effect of intrusive rumination between openness to experience and PTSD symptoms. Moreover, the pathway to intrusive rumination, deliberate rumination, and PTG from openness to experience was also significant. Third, the pathway to posttraumatic cognition, event-related rumination, and both PTSD symptoms and PTG from neuroticism was significant. These results support the cognitive process of PTG model In the end we discussed the implication and limitations of the study.