• 전기학회논문지
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• 제60권2호
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• pp.370-375
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• 2011

In this paper, we propose an antenna module with high isolation between Tx and Rx in RFID reader module. The proposed module consists of a quadrafilar antenna and a directional coupler with a switchable dummy load to improve the directivity. The proposed module achieves the isolation higher than 20 dB between Tx and Rx. To show the validity of the proposed scheme, we have performed the measurement of tagging range and multi-tagging ability. The experiment results show that the detecting range and multi-tagging ability are enhanced by 81% and 200%, respectively.

• 대한전자공학회논문지TC
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• 제43권6호
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• pp.46-52
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• 2006

본 논문에서는 70-nm metamorphic high electron mobility transistor (MHEMT)와 W-band 마이크로 머시닝 링 커플러를 이용하여 낮은 변환손실 및 높은 격리특성의 94 GHz MMIC 믹서를 설계 및 제작하였다. 놀은 LO-RF 격리도 특성을 얻기 위하여 마이크로 머시닝 링 커플러를 사용한 새로운 3차원 구조의 resistive 믹서 구조를 제안하였다. 제작된 93 GHz MMIC 믹서는 94 GHz에서 8.9 dB의 낮은 변환 손실과 29.3 dB의 높은 LO-RF 격리돈 특성을 나타내었다. 본 논문에서 제안된 믹서는 기존의 보고된 W-band 대역 믹서와 비교하여 양호한 변환 손실 뿐 만 아니라 우수한 LO-RF 격리도 특성을 나타내었다.

• 한국공간구조학회논문집
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• 제12권2호
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• pp.99-108
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• 2012

정밀한 공정을 요구하는 반도체 및 TFT-LCD와 같은 첨단 기술산업 공장의 미진동 문제는 제품의 성능에 영향을 주는 주요한 인자로서 정밀기기 및 부품의 제조공정에 있어서 중요시 되어왔다. 본 논문에서는 이러한 첨단시설물의 미진동 문제를 해결하기 위하여 기초면진시스템의 미진동제어성능을 검토하였다. 이를 위하여, 기차에서 유발되는 인공지반운동을 생성하여 시간이력해석을 수행하였고 3층 예제구조물을 사용하였다. 수치해석을 통하여 수동 기초면진 및 스마트 면진시스템의 미진동제어성능을 고정기초구조물과 비교하였다. 그 결과 스마트 면진시스템이 미진동제어에 있어서 우수한 제어성능을 나타내는 것을 확인하였다.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.810-818
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• 2011

This paper analyzed the suitability about the isolation performance criteria which was based on human impedance and effect of current in IEC 60479-1 on the safety of human being was examined. The method of evaluation by megger and DC voltmeter was analyzed. The differences of isolation performance according to design of high-voltage system were analyzed. The factors which affect the insulation performance were analyzed for HFCV, EV, HEV, etc. through analysis of the isolation performance evaluation method. Finally, design for improved isolation performance was proposed.

• 한국전자파학회논문지
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• 제21권8호
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• pp.865-871
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• 2010

본 논문에서는 PMP에 적용 가능한 소형의 듀얼 밴드(IEEE 802.11b: 2.4~2.5 GHz, 11a: 5.15~5.825 GHz) 이중 대역 MIMO 안테나를 제안하였다. 제안된 안테나는 2 GHz 대역에서 동작하는 PIFA(평면형 역 F형 안테나)와 5 GHz 대역에서 동작하는 루프(loop) 안테나로 구성되었다. 두 포트의 안테나는 각각 PIFA와 루프로 구성되어져 있으며, 상호 간의 격리도(isolation)를 높이기 위하여 편파 방향과 최대 방사 방향이 서로 수직이 되도록 그라운드 가장자리에 직교(orthogonal) 구조로 배치하였다. 또한, 상관도(correlation) 저감과 더욱 높은 격리도를 얻기 위해, 2 GHz 동작 주파수 대역에서 두 포트의 PIFA가 $\lambda_g$/4 길이의 선(connecting line)으로 연결되어 있으며, 5 GHz 동작 주파수 대역에서는 그라운드 뒷면에 두 루프 안테나 사이를 연결하는 사다리꼴의 평면(connecting plane)을 이용하였다. 듀얼 밴드 MIMO 안테나는 WLAN 대역에서 충분한 이득을 가지며, PMP(Portable Media Player)에 적용 가능한 소형의 안테나로 설계되었다.

• 대한영양사협회학술지
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• 제19권2호
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• pp.159-172
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• 2013

Food is an essential component of good health and a high quality of life. This is especially true for the elderly, where health and quality of life can vary due to eating issues. This study attempts to measure the satisfaction with food-related life in the elderly of South Korea, while examining differences in social support, depression, isolation, and life satisfaction based on the level of satisfaction with food-related life. Data collection was conducted using one-on-one surveys from December 2011 to January 2012. A total of 390 elderly (aged 65 and over) who live in Korea participated in this study. The results showed that the satisfaction with food-related life was high (3.52 out of 5). The elderly who had company during a meal or a meal preparer showed a higher satisfaction with their food-related life. Social support was high (5.32 out of 7) and the feelings of isolation were low (3.85 out of 5). The average satisfaction with life was 4.42 out of 7, indicating a fair satisfaction with life, while the average depression score was relatively low (8.77 out of 26). In general, the elderly with a higher satisfaction with food-related life had a higher social support and overall satisfaction with their life. On the other hand, the elderly with a lower satisfaction with food-related life generally reported higher levels of depression and isolation. A positive correlation was observed between satisfaction with food-related life, social support, and satisfaction of life, while a negative correlation was found between satisfaction with food-related life, isolation, and depression. The results of this study indicate that managing the satisfaction with food-related life is an important component of mental health in the elderly.

• 국제초고층학회논문집
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• 제6권3호
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• pp.227-235
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• 2017

This paper describes some of the challenges for structural design of a mid-story seismic isolated high-rise building, which is located near Tokyo station, completed in 2015. The building is a mixed-use complex and encompasses three volumes: one substructure including basement and lower floors, and a pair of seismic isolated superstructures on the substructure. One is a 136.5m high Main Tower (office use), and the other is a 98.5 m high South Tower (hotel use). The seismic isolation systems are arranged in the $3^{rd}$ floor of the Main Tower and $5^{th}$ floor of the South Tower, so that we call this isolation system as the mid-story seismic isolation. The primary goal of the structural design of this building was to secure high seismic safety against the largest earthquake expected in Tokyo. We adopted optimal seismic isolation equipment simulated by dynamic analysis to minimize building damage. On the other hand, wind-induced vibration of a seismic isolated high-rise building tends to be excited. To reduce the vibration, the following strategies were adopted respectively. In the Main Tower with a large wind receiving area, we adopted a mechanism that locks oil dampers at the isolation level during strong wind. In the South Tower, two tuned mass dampers (TMDs) are installed at the top of the building to control the vibration. In addition, our paper will also report the building performance evaluated for wind and seismic observation after completion of the building. In 2016, an earthquake of seismic intensity 3 (JMA scale) occurred twice in Tokyo. The acceleration reduction rate of the seismic isolation level due to these earthquakes was approximately 30 to 60%. These are also verified by dynamic analysis using observed acceleration data. Also, in April 2016, a strong wind exceeding the speed of 25m/s occurred in Tokyo. On the basis of the record at the strong wind, we confirmed that the locking mechanism of oil damper worked as designed.

• 한국정보통신학회논문지
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• 제16권1호
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• pp.127-132
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• 2012

본 논문에서는, 초고집적 MOSFET를 위한 향상된 얕은 트랜치 접합 격리에서 높은 임계전압을 위한 활성영역 부분의 제안된 구조의 가장자리 효과를 시뮬레이션 하였다. 얕은 접합 격리는 트랜지스터와 트랜지스터 사이에서 전기적 격리를 하기 때문에 쌍보형-모스 기술에서 중요한 공정 요소이다. 시뮬레이션 결과, 얕은 트랜치 접합 격리 구조가 수동적인 전기적 기능 일지라도, 소자의 크기가 감소됨에 따라서, 초대규모 집적회로 공정의 응용에서 제안된 얕은 트랜치 격리 구조에서 전기적 특성의 영향은 전위차, 전계와 포화 임계 전압에서 높게 나타났다.

• Smart Structures and Systems
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• 제20권3호
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• pp.303-309
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• 2017

Structural control through seismic isolation using elastomeric rubber bearing, which is also known as High Damping Rubber Bearing (HDRB), has seen an increase in use to provide protective from earthquake, especially for new buildings in earthquake zones. Besides, HDRB has also been used in structural rehabilitation of older yet significant buildings, such as museums and palaces. However, the present design approach applied in normal practice has often resulted in dissimilar HDRB dimension requirement between structural designers and bearing manufacturers mainly due to ineffective communication. Therefore, in order to ease the design process, most HDRB manufacturers have come up with catalogs that list all necessary and relevant product lines specifically for structural engineers to choose from. In fact, these catalogs contain physical dimension, compression property, shear characteristic, and most importantly, the total rubber thickness. Nonetheless, other complicated issues, such as the relationship between target isolation period and displacement demand (which determines the total rubber thickness), are omitted due to cul-de-sac fixing of these values in the catalogs. As such, this paper presents a formula, which is derived and extended from the present design approach, in order to offer a simple guideline for engineers to estimate the required HDRB size. This improved design formula successfully minimizes the discrepancies stumbled upon among structural designers, builders, and rubber bearing manufacturers in terms of variation order issue at the designing stage because manufacturer of isolator is always the last to be appointed in most projects.

• 한국소음진동공학회논문집
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• 제23권4호
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• pp.332-337
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• 2013

This paper presents a subsequent research work on the roller design of IRB(isolation roller bearing) seismic isolation device presented in Part 1 by focusing on heat treatment. The hardness and friction factor are very important factors of material and after-treatment process selection. Normally, roller bearing consists of roller and retainer. The roller gets high pressure constantly, while the retainer gets tensile and compressive stress. Therefore, sensitive material selection and heat treatment of each part is quite important. In this experimental evaluation, carbon steel, chrome special steel and others are employed and their characteristics after heat treatment are identified. Each material is prepared by refining high frequency heat treatment. The friction factor and static load capacity of manufactured material are experimentally identified and destructive test of material is processed. Optimal material and heat treatment conditions for IRB roller bearing are determined based on experiment results.