• Journal of Digital Convergence
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• v.16 no.7
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• pp.429-439
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• 2018

The objective of the study was to analyze difference in cognitive function according to social isolation level in elderly Korean. The author classified the social isolation into the structural isolation and contact isolation. Structural isolation corresponded to the no spouse or no children and the contact isolation corresponded to the absence of contact with children, friends or social association. Author conducted multivariate regression analysis with the elderly people aged 65 years or older from the 5th wave of the Korean Longitudinal Study of Ageing data. Number of sample was 3,971. It was confirmed that the level of cognitive function was lower according to level of social isolation. It was also confirmed that friends/neighborhood isolation, and social activity isolation showed significant relationships with cognitive functions. Based on the results, author suggested that to protect the elderly from negative effects of social isolation, we needed the policy to promote elderly's the participation in social activity. The study to analyze the factors related to social isolation was also needed.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1509_1510
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• 2009

This paper presents the design and simulation results of ohmic contact RF MEMS silicon switch with a high isolation at high frequencies along with the position of a contact part, initial off-state and intermediate off-state including the state where a contact part is placed right over a signal line of coplanar waveguide (CPW). The ohmic contact part is connected with comb drives made of high resistivity single crystalline silicon. The released contact part is $30{\mu}m$ apart from the edge of signal line on the glass substrate along the lateral direction (x-direction) at initial off-state. The electrostatic force of the comb electrode creates the x-directional movement thus initial state is converted to the intermediate off-state. The initial off-state of the switch results in isolations of -31 dB, -24 dB and reflections of -0.45 dB, -0.67 dB at 50 GHz and 110 GHz, respectively. It shows the isolation degradation when the contact part moves right over the signal line of CPW like an initial off-state of a conventional MEMS switch. The isolations and reflections are -31 dB, -24 dB and -0.50 dB, -1.31 dB at 50 GHz and 110 GHz, respectively at the intermediate off-state.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.953-956
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• 2005

Low voltage actuation and high isolation characteristics are key features to be solved in electrostatic RF switch design. Since these parameters in the conventional parallel plate MEMS switch design are in trade-off relation, both requirements cannot be met simultaneously. In vertical comb design, however, the actuation voltage is independent to the vertical separation distance between the contact electrodes. Then, we can design the large separation distance between contact electrodes to get high isolation. We have designed an RF MEMS switch which has -40dB isolation at 5 GHz and 6 V operation voltages. The characteristics of the fabricated switch are being evaluate.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.177-182
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• 2007

This paper presents the see-saw type RF MEMS switch based on a single crystalline silicon structure with narrow gap vertical comb. Low actuation voltage and high isolation are key features to be solved in electrostatic RF MEMS switch design. Since these parameters in conventional parallel plate RF MEMS switch designs are in trade-off relationship, both requirements cannot be met simultaneously. In the vertical comb design, however, the actuation voltage is independent of the vertical separation distance between the contact electrodes. Therefore, the large separation gap between contact electrodes is implemented to achieve high isolation. We have designed and fabricated RF MEMS switch which has 46dB isolation at 5GHz, 0.9dB insertion loss at 5GHz and 40V actuation voltage.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.76.1-76.1
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• 2010

Furnace를 이용한 $POCl_3$ 확산 공정은 실리콘 태양전지 제작과정에서 일반적으로 이용되는 에미터 층 형성 공정이다. 하지만, 확산 공정을 통해 P-N Junction을 형성할 경우 전면과 후면의 contact현상이 발생하게 되고 이를 제거하기 위해 Edge isolation 공정을 거치게 된다. 최근에는 레이저로 V 모양의 홈을 형성하는 방법이 이용되고 있다. 본 연구에서는 p-type 실리콘 웨이퍼 기판에 insulating barrier를 형성하여 edge isolation 공정을 없앤 Non-edge isolation공정을 제시한다. Non p-type 실리콘 웨이퍼에 insulating barrier를 형성한다. Insulating barrier가 형성된 BOE용액과 KOH에서의 견딤성 실험을 진행 하였다. 이후, p-type 단결정 실리콘 태양전지의 확산 공정을 진행하여 Non edge isolation 공정을 진행한 경우와 laser를 이용한 edge isolation 공정을 진행한 태양전지를 제작하여 특성을 비교하였다.

• Journal of Preventive Medicine and Public Health
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• v.48 no.6
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• pp.277-279
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• 2015

Contact monitoring is an essential component of the public health response to a Middle East respiratory syndrome coronavirus outbreak, and is required for an effective quarantine to contain the epidemic. The timeliness of a quarantine is associated with its effectiveness. This paper provides a conceptual framework to describe the process of contact monitoring, and proposes a new measure called the "timely quarantined proportion" as a tool to assess the adequacy of a public health response.

• Earthquakes and Structures
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• v.18 no.4
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• pp.467-480
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• 2020

Concrete rectangular liquid storage tanks are widely used, but there are many cases of damage in previous earthquakes. Nonlinear fluid-structure interaction (FSI) is considered, Mooney-Rivlin material is used for rubber bearing, nonlinear contact is used for sliding bearing, numerical calculation models of no-isolation, rubber isolation, sliding isolation and hybrid isolation concrete rectangular liquid storage tanks are established; dynamic responses of different structures are compared to verify the effectiveness of isolation methods; and influences of earthquake amplitude, bidirectional earthquake and far-field long-period earthquake on dynamic responses are investigated. Results show that for liquid sloshing wave height, rubber isolation cause amplification effect, while sliding isolation and hybrid isolation have reduction effect; displacement of rubber isolation structure is much larger than that of sliding isolation with limiting-devices and hybrid isolation structure; when PGA is larger, wall cracking probability of no-isolation structure becomes larger, and probability of liquid sloshing wave height and structure displacement of rubber isolation structure exceeds the limit is also larger; under bidirectional earthquake, occurrence probabilities that liquid sloshing wave height and structure displacement of rubber isolation structure exceed the limit will be increased; besides, far-field long-period earthquake mainly influences structure displacement and liquid sloshing wave height. On the whole, control effect of sliding isolation is the best, followed by hybrid isolation, and rubber isolation is the worst.

• Biomedical Science Letters
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• v.18 no.3
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• pp.324-327
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• 2012

Acanthamoeba is a free-living amoeba that causes human infections, and recently the incidence of amoebic keratitis has increased among contact lens wearers. In order to investigate Acanthamoeba contamination of contact lens storage cases, a short survey was performed on 57 contact lens wearers, and Acanthamoeba was found in one contact lens storage case. To diagnose Acanthamoeba, the 18s small subunit ribosomal DNA (18s rDNA) gene was amplified by polymerase chain reaction (PCR), and subsequently, the isolate was identified as A. lugdunensis. This species was originally isolated from a freshwater pool in France, and was reported recently to be a cause of amoebic keratitis. This observation indicates the need for a large survey to investigate the extent of Acanthamoeba contamination, and suggests that contact lens wearers be aware of the importance of hygiene and of the implications of Acanthamoeba infection.

• Earthquakes and Structures
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• v.15 no.5
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• pp.513-528
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• 2018

A typical viable technique to decrease the seismic response of liquid storage tanks is to isolate them at the base. Base-isolation systems are an efficient and feasible solution to reduce the vulnerability of structures in high seismic risk zones. Nevertheless, when liquid storage tanks are under long-period shaking, the base-isolation systems could have different impacts. These kinds of earthquakes can damage the tanks readily. Hence, the seismic behaviour and vibration of cylindrical liquid storage tanks, subjected to earthquakes, is of paramount importance, and it is investigated in this paper. The Finite Element Method is used to evaluate seismic response in addition to the reduction of excessive liquid sloshing in the tank when subjected to the long-period ground motion. The non-linear stress-strain behaviour pertaining to polymers and rubbers is implemented while non-linear contact elements are employed to describe the 3-D surface-to-surface contact. Therefore, Nonlinear Procedures are used to investigate the fluid-structure interactions (FSI) between liquid and the tank wall while there is incompressible liquid. Part I, examines the effect of the flexibility of the isolation system and the tank aspect ratio (height to radius) on the tank wall radial displacements of the tank wall and the liquid sloshing heights. Maximum stress and base shear force for various aspect ratios and different base-isolators, which are subjected to three seismic conditions, will be discussed in Part II. It is shown that the composite-base isolator is much more effective than other isolators due to its high flexibility and strength combined. Moreover, the base isolators may decrease the maximum level pertaining to radial displacement.

• Journal of the Korean Home Economics Association
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• v.40 no.3
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• pp.21-40
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• 2002

The aim of this interdisciplinary study is to understand the relationship between the social behavior patterns and space elements, specially micro-housing sociological point of view. It analyzed korean typical floorplans in the apartment housing, focused on the 4-criteria contact or isolation between the individual persons, communication between the generations, hierarchy of the gender and socialization with neighbourhood. It determinate concrete space elements involved correspondent factors with users' social behavior. By reviewing those factors found, it is suggested also the planning concept, that response users' social orientation. As the practical alternatives, some prototypes have been developed not only for improvement of housing plans, but also for resonable housing supply and sustainable usage.