• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.227-232
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• 2003

As the most precision equipment requiring very strict vibration environment are vulnerable to the surrounding vibration condition, they adapt the passive or active vibration isolation system. When it comes to the passive isolation system, the resonance of the isolation system causes excessive resonance response, and finally results in the degrade the equipment performance. This paper deals with the active control method to control this resonance induced response, and includes the experiment on the active control for controlling the resonance response on the table against the excitation of the same frequency with the natural frequency of the isolation system. The electromagnetic actuator was designed and the control effect was verified by the experiment. The experiment showed that the electromagnetic actuator is effective for controlling the low frequency isolation resonance response of the precision equipment.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.75-80
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• 2020

In this study, we designed car frames for collision analysis using carbon fiber reinforced polymer (CFRP) as the lighter composite material. The impact conditions were 100 percent frontal impact, 40 percent frontal impact, and 90 degrees side impact. The impact analysis measured the maximum stress at velocities of 20km/h and 40km/h for each condition and evaluated the vulnerable points in the car frame. Additional supports have been designed both to improve the weak points in existing vehicle frames, and to be taken into account when new parts are assembled. Our impact analysis compared the results of maximum stress on the car frame with and without the support.

• Journal of Korean Biological Nursing Science
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• v.18 no.3
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• pp.185-191
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• 2016

Purpose: The purpose of this study is to understand the effect of taking calcium/vitamin D supplements and performing Taekkyeon exercises on the frailty of the elderly targeting a vulnerable senior social group. Methods: A total of 124 people aged 65 and older consisting of 60 persons in the experimental group, and 64 persons in the control group participated in this study, and this study is a non-equivalent control group pre/post-test design quasi-experimental study. This study analyzed the homogeneity between the experimental group and the control group using a chi-square test and t-test while analyzing the difference in the degree of frailty and bone density with the practice of Taekkyeon and a calcium agent using t-test and GEE. Results: The study results showed that the frailty and bone density of the experimental group significantly improved. Conclusion: Through this study, it was confirmed that calcium/vitamin D intake and Taekkyeon exercises were an effective intervention which strengthened the elderly's physical condition.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.281-288
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• 2000

Three-dimensional dynamic analysis of underground openings subjected to explosive loadings considering the effects of water saturation is carried out in this study. The problem considered in this study is an unlined circular tunnel subjected to a finite cylindrical charge placed at the center of the proposed tunnel. The surrounding rock mass is assumed to be the limestone with 13.5% of porosity. Two calculations are compared using an identical explosive charge; the first in dry rock of 13.5% porosity, the second in the identical rock, but in a fully saturated condition. It is shown that underground openings in saturated porous medium could be significantly more vulnerable to the potential damages associated with high motions and shear failure than those in dry medium.

• Journal of Korean Association for Spatial Structures
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• v.17 no.2
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• pp.63-70
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• 2017

In Korea, the occurrence frequency of earthquakes has recently increased, compared with the past. So, the various damages for cultural properties due to earthquake can be expected, and especially fortress structure is vulnerable to earthquake. Therefore, the resonable seismic characteristics evaluation is required to secure the safety for fortress structure with the various construction and configuration types. Also, we should consider the various applied load conditions as design variables. To this end, this study classifies fortress structures according to the construction and configuration types, and then applies the discrete element method to model and analyze fortress structures. Finally, the seismic characteristics is evaluated through slip condition due to the analysis results considering the various design variables.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.219-220
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• 2017

Current domestic waterproofing market in Korea mainly uses single-ply waterproofing materials comprised of coatings or waterproof sheets and two or more-ply composite waterproofing methods. In order to evaluate these types of composite waterproofing systems, a new test equipment and method that incorporates various deterioration conditions (joint displacement, chemical exposure, water pressure etc) was developed. In a comparison testing, the results showed that flexible type materials have higher response performance towards joint displacement than the hardened material. Furthermore, the importance of securing the stability of the waterproofing method in the vulnerable over-lap joint areas of waterproofing sheets is emphasized.

• Proceedings of the KIEE Conference
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• 2005.11c
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• pp.44-46
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• 2005

An Electrical facilities of fountain is one of the vulnerable facilities because it is exposed to water. Especially, some children enter the fountain and play in the water in the hot season. For example, death from electrical shock in fountain was reported in domestic and foreign papers. In this paper, we analyzed the riskiness of electrical shock on the basis of a fact-finding survey and comparing the domestic and international standard of electrical facilities in fountains.

• Journal of Korean Society of Rural Planning
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• v.15 no.1
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• pp.15-29
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• 2009

Owing to the industrialization, the urbanization and cultivation abandonment actual condition, the most abandoned farmlands increased. Those results have occurred inefficient land use and destruction of agricultural ecosystem with the secondary succession. The research for the abandoned farmlands of Korea is fundamental phase. Also, the researches to restore abandoned farmlands are something yet to develop and not established the restoration for ecological value of abandoned farmlands. The objective of research revealed the ecological functions of abandoned farmlands and it presented an application plan. The research method divided in the literature and case study. Using abandoned farmlands, Japan government tries to create the ecological parks for the conservation of a vulnerable plant species, dragonfly biotope, environmental education and research, etc. Accordingly, the goal for the abandoned farmlands coulds be set suitably to Korean situation as of Japanese styles which are characterized by man-made biotopes.

• International Journal of Industrial Entomology and Biomaterials
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• v.20 no.2
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• pp.45-59
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• 2010

It is well established fact that under tropical condition, unlike polyvoltines, bivoltines are more vulnerable to various stresses i.e. hot climatic conditions of tropics, poor leaf quality and improper management during summer which are not conducive for bivoltine rearing. Therefore, attempt has been made in this study to develop promising bivoltine breeds tolerant to high temperature and high humidity conditions of the tropics. In the present study, by utilizing temperature tolerant breeds six breeding lines were made and at every generation the 5th instar larvae were exposed to high temperature and high humidity and the survived ones were back crossed with the breeds moderately tolerant to diseases were made to improve the quantitative traits. From F6 generations, alternate rearing in normal temperature and high temperature were conducted. At the end of F12 generation, it was possible to isolate three dumbbell breeds viz., HH8, HH10 and HH12 with improvement in quantitative traits. The methodologies followed for the development are discussed.

• Journal of The Korea Institute of Healthcare Architecture
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• v.27 no.3
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• pp.61-69
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• 2021

Purpose: Senior long-term care facilities are vulnerable to a cluster infection because of frequent physical contact, large group dining, communal living, and room sharing. This study aims to provide architectural improvement plans for a quarantine system in the facilities. Methods: Actual quarantine action data, guidelines from governments and institutes, in-depth interviews with facility staff are analyzed. Results: To prevent a cluster infection in the senior facilities, it is necessary to provide an architectural plan focusing on increasing the number of single rooms and isolation rooms, providing isolation rooms for staff, separation of a soiled room from a clean room, planing an entry vestibule and a visitor's room. Implications: It is important to analyze the existing condition of facilities that had been going through cohort isolation and provide the architectural solution to strengthen infection control.