• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.97-103
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• 2002

Vibration isolation technology using an air spring and laminated rubber bearing is widely used because it has excellent vibration isolation characteristics. In the part of that, we usually make use of the self-damped air suing. It is occupied two chambers, restrictor, diaphragm and load plate. Two chambers contain compressed air and the volume of chambers and the area of load plate give a definition of stiffness and load. The restrictor and the volume ratio of two chambers give a definition of damping ratio. The conventional model of restrictor is made of one orifice and it causes turbulent flow in the orifice at the region of large deflection. The stillness of air suing is larger and the damping is lower in the region of large deflection. In the multi-orifice case, the stiffness is similar to air spring with one orifice but damping ratio is larger than conventional air spring. And damping ratio is smaller than conventional air suing in small deflection region. Deflection is small in the region of high frequency so small damping is better than large damping. As a result, we can reduce the storage stiffness of air suing in the wide region of deflection and increase the damping ratio in the region of large deflection. After this, we will try to and the relation of Reynolds Number and Flow Resistance then we are going to make another restrictor for air spring to improve damping ratio and stiffness.

• 대한예방한의학회지
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• 제20권2호
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• pp.53-67
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• 2016

Objectives : The aim of this study was to explore the academic failure experiences of Korean Medicine Students. The academic failure in a medical school is defined as the situation the student who have academic failure need to repeat their academic year again. Methods : Data were collected through in-depth individual interviews from April to May 2016 and analyzed through Colaizzi's phenomenological methodology. The participants were interviewed twice, for 30minutes to 60minutes per interview. Results : Eight theme-clusters of were identified from 21 themes. The theme-clusters were 'Dream of university life and freedom', 'Meeting Stranger academic field and growing study stress', 'Difficulty of self-management', 'Weak supporting system', 'Feeling of guilty, sense of isolation and decreasing in self-esteem', 'The experience during the vacation after the academic failure', 'The experience of returning to school' and 'Self growing through hard experience'. Conclusions : Understanding of academic failure experience of Korean Medicine Students is an important approach to counsel them and an important way to reach a good model of education at a medical college.

• Smart Structures and Systems
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• 제8권2호
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• pp.173-190
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• 2011

As a practical and effective seismic resisting technology, the base isolation system has seen extensive applications in buildings and bridges. However, a few problems associated with conventional lead-rubber bearings have been identified after historical strong earthquakes, e.g., excessive permanent deformations of bearings and potential unseating of bridge decks. Recently the applications of shape memory alloys (SMA) have received growing interest in the area of seismic response mitigation. As a result, a variety of SMA-based base isolators have been developed. These novel isolators often lead to minimal permanent deformations due to the self-centering feature of SMA materials. However, a rational design approach is still missing because of the fact that conventional design method cannot be directly applied to these novel devices. In light of this limitation, a displacement-based design approach for highway bridges with SMA isolators is proposed in this paper. Nonlinear response spectra, derived from typical hysteretic models for SMA, are employed in the design procedure. SMA isolators and bridge piers are designed according to the prescribed performance objectives. A prototype reinforced concrete (RC) highway bridge is designed using the proposed design approach. Nonlinear dynamic analyses for different seismic intensity levels are carried out using a computer program called "OpenSees". The efficacy of the displacement-based design approach is validated by numerical simulations. Results indicate that a properly designed RC highway bridge with novel SMA isolators may achieve minor damage and minimal residual deformations under frequent and rare earthquakes. Nonlinear static analysis is also carried out to investigate the failure mechanism and the self-centering ability of the designed highway bridge.

• 한국학교ㆍ지역보건교육학회지
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• 제11권1호
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• pp.117-134
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• 2010

Background & Objectives: Recently, problems such as in-school violence of teenagers, gang fight, habitual drinking, smoking, running away from home and group isolation can be regarded as the most fundamental causes of teenagers' deviation. It is said that such fundamental causes are originated from their home, the base for the psychological and behavioral development. Methods: In this study, the data for 3,188 students studying in the 3rd grade at middle school, which have been obtained from the second year survey for the panel of the 2nd grade students in 2004 by to Korea Youth Panel Survey, have been used for the analysis of the study. Results: According to the result of the study, there seems to be no difference between two genders for differences of average values. Regarding the analysis of correlation coefficients between such related variables as domestic violence, self-control, self-worth, self-trust and family relationship (sociability), and teenagers' deviation, When variables increase, teenagers' deviation decreases. Regarding the relationship between domestic violence and teenagers' deviation, physical violence is more related than lingual violence. The relationship between self-control and teenagers' deviation is the highest. By studying the deviation of teenagers exposed to domestic violence and carrying out the regression analysis, physical violence influences, teenagers' deviation was greater. As self-control, self-worth and family relationship(sociability) increase, teenagers' deviation decreases. Regarding the analytic results of this study, the experience of domestic violence seems to influence teenagers' deviation greatly. Among various types of domestic violence, physical violence is analyzed to influence teenagers' deviation greatly. Self-control, self-worth and family relationship(sociability) increase, teenagers' deviation decreases. Conclusions: In order to prevent teenagers' deviation and decrease the second conviction rate, it is necessary to provide a method of decreasing the domestic violence. It is necessary for schools and local communities to provide social support for teenagers.

• Nuclear Engineering and Technology
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• 제31권6호
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• pp.66-82
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• 1999

The national long-term R&D program, updated in 1997, requires Korea Atomic Energy Research Institute(KAERI) to complete by the year 2006 the basic design of Korea Advanced Liquid Metal Reactor(KALIMER), along with supporting R&D work, with the capability of resolving the issue of spent fuel storage as well as with significantly enhanced safety. KALIMER is a 150 MWe pool-type sodium cooled prototype reactor that uses metallic fuel. The conceptual design is currently under way to establish a self-consistent design meeting a set of major safety design requirements for accident prevention. Some of the current emphasis includes those for inherent and passive means of negative reactivity insertion and decay heat removal, high shutdown reliability, prevention of and protection from sodium chemical reaction, and high seismic margin, among others. All of these requirements affect the reactor design significantly and involve extensive supporting R&D programs. This paper summarizes some of the results of conceptual engineering and design analyses performed for the safety of HAMMER in the area of inherent safety, passive decay heat removal, sodium water reaction, and seismic isolation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.187-190
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• 1999

This study is intended to present the properites of planting concrete using the light-weight aggregate and crushed aggregate. According to the result of experiment, the concrete using orchid stone shows a better performance in voids volume, unit weight, absorbtion, thermal conductivity and pH, which are helpful for planting and heat isolation. Therefore, if planting concrete used with orchid stone are utilized to be the planting base on the building's roof, it will be effective to reduced the cost of construction and heating due to the redution of building's self weight and heat isolation effection.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2002년도 종합학술발표회 논문집 Vol.12 No.1
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• pp.177-181
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• 2002

In this paper, the cancellation or suppression of the feedback interference from Tx antenna using the same frequency is studied. The major problems on the wireless communication system using the same frequency or on-frequency repeater (OFR) are the coupling and isolation between Rx and Tx antenna. In order to increase the isolation between Rx and Tx antenna and to Prevent the self-oscillation of the receiver system, this paper is verified the possibility of the application of interference cancellation system and proposed the design method of the OFR using interference cancellation system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권5호
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• pp.999-1012
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• 2011

This paper proposes an algorithm that enables mobile nodes to implement self-regulated movements in mobile ad-hoc networks (MANETs). It is important for mobile nodes to maintain a certain level of network-based stability by harmonizing these nodes' movements autonomously due to their limited transmission range and dynamic topology. Entropy methods based on relative position are suggested, as a means for mobile nodes to regulate their local movements. Simulations show that an early warning mechanism is suitable to maintain movement-based stability. Isolation can be reduced by 99%, with an increased network cost of 12% higher power consumption, using the proposed algorithm.

• 한국컴퓨터산업교육학회:학술대회논문집
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• 한국컴퓨터산업교육학회 2003년도 제4회 종합학술대회 논문집
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• pp.67-70
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• 2003

In this paper, propose a new structure of MOFET(Metal-Oxide-Semiconductor Field Effect Transistor) which is widely application for semiconductor technologies. Eleminate the latch-up effect caused by closed devices when conpose a electronic circuit using proposed devices. In this device have a completely isolation structure, and advantage of leakage current elimination. Each independent devices are isolated by trench-well and oxide layer of SOI substrate. Using trench gate and self aligned techniques reduces parasitic capacitance between gate and source, drain. In this paper, we proposed the new structure of SOI MOSFET which has completely isolation and contains trench gate electrodes and SOI wafers. It is simulated by MEDICI that is device simulator.

• 한국환경농학회지
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• 제34권3호
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• pp.238-243
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• 2015

BACKGROUND: Yeasts associated with fleabane flowers were identified using isolation methods previously applied in yeast biotechnology. A culture-based approach was required for isolation of many yeast strains associated with fleabane. METHODS AND RESULTS: We spread homogenized fleabane flowers onto GPY medium containing chloramphenicol, streptomycin, Triton X-100, and L-sorbose. We isolated 79 yeast strains from the flowers of wild fleabane, and identified the yeasts via phylogenetic analysis of isolates from agar plates. The yeast species included 39 isolates of Aureobasidium pullulans, 17 of the genus Candida, 14 of the genus Rhodosporidium, 6 of the genus Cryptococcus, and 3 of the genus Rhodotorula. CONCLUSION: Yeast isolates associated with fleabane flowers included A. pullulans (39 isolates) and other yeast species (40 isolates). Such yeast isolates may have biotechnological potential.