• 한국CDE학회논문집
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• 제16권3호
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• pp.236-245
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• 2011

Many researchers have recently studied multi-level formulation strategies to solve the MDO problems and they basically distributed the coupling compatibilities across all disciplines, while single-level formulations concentrate all the controls at the system-level. In addition, approximation techniques became remedies for computationally expensive analyses and simulations. This paper studies comparisons of the MDO methods with respect to computing performance considering both conventional sequential and modem distributed/parallel processing environments. The comparisons show Individual Disciplinary Feasible (IDF) formulation is the most efficient for sequential processing and IDF with approximation (IDFa) is the most efficient for parallel processing. Results incorporating to popular design examples show this finding. The author suggests design engineers should firstly choose IDF formulation to solve MDO problems because of its simplicity of implementation and not-bad performance. A single drawback of IDF is requiring more memory for local design variables and coupling variables. Adding cheap memories can save engineers valuable time and effort for complicated multi-level formulations and let them free out of no solution headache of Multi-Disciplinary Analysis (MDA) of the Multi-Disciplinary Feasible (MDF) formulation.

• 한국통신학회:학술대회논문집
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• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
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• pp.549-549
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• 2006

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 1999년도 추계 기술심포지움 논문집
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• pp.33-36
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• 1999

In this paper, we proposed a simultaneous switching noise(SSN) reduction technique in muti-layer beards(MLB) for high-speed digital applications and analyzed them using the Finite Difference Time Domain(FDTD) method. The new method by conductive dielectric substrates reduces SSN couplings and resonances, significantly, which cause series malfunctions in the modem high-speed digital applications.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2011년도 추계학술발표대회
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• pp.595-598
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• 2011

초음파를 이용한 통신은 지상 통신에 비해 작은 대역폭을 사용하기 때문에 하나의 통신 주파수를 사용하거나 그 이상의 주파수를 사용한다. 또 수중 통신의 대역폭이 작기 때문에 사용 주파수가 다른 모뎀을 사용하더라도 서로 간섭이 발생되는 경우가 있어 통신을 할 수 없게 된다. 본 연구에서는 한 시스템에서 사용 주파수가 다른 모뎀을 사용할 때 서로간의 주파수 충돌을 회피함으로써 네트워크상에서 통신을 보장하는 미들웨어를 연구하고자 한다.

• 한국통신학회논문지
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• 제25권9A호
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• pp.1332-1339
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• 2000

본 논문에서는 MCNS(Multimedia Cable N$\xi$twork System)의 DOCSIS(Data Over Cable Service Interface S Specification) 표준안의 물리계층을 지원하는 비대칭형 기저대역 모댐 ASIC 칩의 아키텍쳐와 설계에 대해 기술한다. 구현한 모뎀 칩은 크게 QPSK/16-QAM 방식의 상향 스트림용 송신부와 64/256-QAM 방식의 하향 스트림용 수신부로 구성되어 있으며, 심볼 타이밍 복구회로, 반송파 복구회로. MMA(Multi Modulus Algorithm)와 LMS(Least Mean Square) 알고리즘을 적용한 결정 궤환 구조의 블라인드 등화기를 포함한다. 구현한 모뎀 칩은 64/256-QAM 변복조 방식에서 각각 48Mbps, 64Mbps의 데이터 전송률을 지원하고, 심볼 전송률은 기존의 QAM 수신기들보다 빠른 8MBaud를 갖는다. 구현한 칩은 $0.35\mu\textrm{m}$ 표준 셀(Standard Cell) 라이브러리를 사용하여 논리합성을 수행하였으며, 총 게이트 수는 약 29만 게이트이며, 현재 ASIC 칩으후 제작중이다.

• 교육시설 논문지
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• 제19권1호
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• pp.3-12
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• 2012

The opportunity provided for design method and strategy of community space for secondary school through the experience of public library and gallery, is the purpose of this paper. Community space is an important issue in school architecture as it seeks to revive the public area in educational building and to renew the open space as a multi-entertainment space. The latest works of school, however, which are evaluated as well reflected the reality of educational patterns, are still deficient in that communicational elements in school are underdeveloped and inadequate. The cases of this paper, which are grown up as entertainment library and multi-purpose cultural space such as Seattle Public Library, Sendai Mediatech, Tate Modem Gallery, and Kunsthaus, are suitable to offer the method of the creation of community space for school. This paper reviews an assessment of its success in community space for school architecture with multi-entertainment-purpose library and cultural space connected open space and concludes with the establishment of design method for future school; extraction of the factors contributing to development of community space in school and proposal of design method; implementation of school renewal with library and gallery plus open space for the creation of identity considering both of study and play.

• ETRI Journal
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• 제36권2호
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• pp.206-213
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• 2014

This paper presents a novel 90 GHz band 16-quadrature amplitude modulation (16-QAM) orthogonal frequency-division multiplexing (OFDM) communication system. The system can deliver 6 Gbps through six channels with a bandwidth of 3 GHz. Each channel occupies 500 MHz and delivers 1 Gbps using 16-QAM OFDM. To implement the system, a low-noise amplifier and an RF up/down conversion fourth-harmonically pumped mixer are implemented using a $0.1-{\mu}m$ gallium arsenide pseudomorphic high-electron-mobility transistor process. A polarization-division duplex architecture is used for full-duplex communication. In a digital modem, OFDM with 256-point fast Fourier transform and (255, 239) Reed-Solomon forward error correction codecs are used. The modem can compensate for a carrier-frequency offset of up to 50 ppm and a symbol rate offset of up to 1 ppm. Experiment results show that the system can achieve a bit error rate of $10^{-5}$ at a signal-to-noise ratio of about 19.8 dB.

• 한국실내디자인학회논문집
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• 제14권5호
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• pp.52-61
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• 2005

Ecological traces appearing in contemporary architecture are based on modern architecture and most aspects on the contemporary architecture are related with the successive trend or break of the modern architecture. The concept of environment in the modern age has established clear destination, as it has been considered as nature. The architecture under a mechanical world view in the modem age has sustained the opposing connection with nature as environment. However, there have been architects maintaining the sympathy with nature in that vortex. This trend has been regarded as same context as ecological architecture and estimated to the outpost of ecological characteristics appearing in the contemporary architecture. This study is to make it clear that the ecological manifestation in the contemporary architecture is based on the ecology in the modem architecture through considering ecological ideals of architects in the modern architecture and considering space composition and structural properties in the modern architecture of ecological paradigm. The scope of this study contains spacial analysis, design strategy, and design types of organic architecture in nature, which has appeared from the modern age. First, the division into period is carried out according to the organic tendency of non-mainstream in the modern architecture: Arts and Crafts Movement, Art Nouveau, Sezession, Expressionism, Organic Architecture, Regionalism, Internationalism. Therefore, this study is significant to be on the search for a start to suggest ecological point of view to architectural space in modern architecture and is search organic characteristics for ecological characteristics in modern architecture; organic relation, thermal buffer space, regionalism, multi-layer, energy efficiency.

• 한국통신학회논문지
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• 제28권4B호
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• pp.257-269
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• 2003

S-DMT는 새롭게 부각되고 있는 ADSL 시스템의 전송 방법으로 상향 채널에 적용할 수 있는 케이블 모뎀 기술로서 고속의 멀티미디어 통신을 가능하게 한다. 본 논문에서는 S-DMT의 송수신 동작 과정을 분석하고 케이블 상향 채널을 잘 반영할 수 있는 $\varepsilon$-복합 임펄스 모델을 적용하여 S-DMT의 비트 에러 확률을 유도하였다. 이 분석 결과는 모의 실험 결과와 잘 일치함을 보인다. 또한 16,32,64 QAM 에 대한 S-DMT의 Eb/No 이득 성능을 기존의 TDMA 방식과 비교하였다.

• 조명전기설비학회논문지
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• 제21권1호
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• pp.148-156
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• 2007

본 논문은 원거리 및 직선구간에 동작되어지는 Stocker 시스템에 대해 설명하고 있다. 파티클 발생을 줄이기 위해 Stocker의 전원은 비접촉 전원장치를 사용한다. 기존 비접촉 전원장치보다 회로구성과 토폴로지를 간략화 하였다. 이를 바탕으로 시제품을 제작하여 상용화에 가능함을 보이고자 한다. 비접촉 전원장치 전체 제어 시스템의 구조는 1차측 전원공급장치와 2차측 전원공급장치간 상호 정보를 광모뎀 통신과 TMS320F243을 사용한 구조이며, 비접촉 전원장치와 출력제어를 위해 주파수 제어를 사용하였다. 본 논문에서는 광모뎀 통신을 사용함으로써 크레인의 이동부(2차측 전원공급장치)와 고정부(1차측 전원공급장치)간 1:1통신으로 제어되는 상용화 Stocker 시스템에 적용하였으며, 향후, Stocker 시스템의 멀티 Crane의 동작을 위해 비접촉 전원장치의 고정부와 이동부간 1:다수가 제어 가능하게 하는 연구가 이루어져야 할 것으로 생각된다.