• 한국통신학회논문지
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• 제25권4A호
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• pp.539-545
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• 2000

본 논문에서는 Radix-4 방식의 64-state, R=1/2, 3비트 연판정 Viterbi 복호기를 설계하고 FLEX10K CPLD 칩으로 제작하였다. Viterbi 복호기 동작을 고속화하기 위해 Viterbi 복호기를 구성하고 있는 모듈인 ACS, BMU, TB 구조를 제시하였다. 실제 ASIC 설계시, CPLD 칩으로 제작한 것 보다 6∼7 배의 속도를 빨리할 수 있으므로 본 연구에서 제시한 40Mb/s급 Viterbi 복호기 구조는 200Mb/s급 무선멀티미디어통신에서 적용할 수 있다.

• 교육녹색환경연구
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• 제9권3호
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• pp.34-40
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• 2010

In this study, vibration characteristics of reinforced concrete slab in large span educational facilities were evaluated. A 21.75m X 14.4m full scale reinforced concrete slab specimen was constructed with pre-flex hybrid beams. Vibrations were generated by three different methods such as free falling method of a 6kg sand bag, a 70kg person walking method and impact method by impulse hammer. Vibrations were generated more than 3 times at single location. Vibration characteristic data were collected by SA390 signal analyzer machine at 5 different locations.

• 한국의류학회지
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• 제21권2호
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• pp.471-481
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• 1997

Denims were treated with neutral cellulase, acid cellulase, stone, and stone-neutral cellulase respectively at different cellulase concentrations varying treatment times in rotary washer. The effect of washing on denim was estimated by the changes in weight, color, back staining, tear strength, flex stiffness, and surface characteristics. Also the comparison of neutral cellulase, acid cellulase, stone, and stone-neutral cellulase washings was studied. Washing removes surface fibers and provides weight loss, color difference, back staining, and a decrease in tear strength and in flex stiffness. Stone-neutral cellulase washing and acid cellulase washing have a larger washing effect than neutral cellulase washing and stone washing.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.438-441
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• 2000

본 논문에서는 Shannon's Limit 보다 근접한 성능을 나타낼 수 있는 Turbo 부호의 기본 이론과 MAP, Log-MAP 복호알고리즘을 정리하고, 이를 바탕으로 VHDL(Very high speed integrated circuit Hardware Description Language)를 이용하여 Log-MAP Turbo 복호기를 ALTERA 사의 FLEX10k100 CPLD(Complex Programmable Logic Device)에 구현하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.226-230
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• 2000

본 논문에서는 CPLD 칩을 이용하여 QPSK 복조기를 구현하고, 그 결과를 검토하였다. 복조기는 비트 동기를 포착하는 STR(Symbol Timing Recovery) loop와 반송파 동기를 포착하는 CPR(Carrier Phase Recovery) loop로 구성된다 STR loop는 DD-Gardner 방식을, CPR loop는 빠른 반송파 포착을 위하여 Decision-Directed 동기화 방식을 이용하여 구현한 결과를 제시하였다. Altera사의 Design Compiler를 이용하여 FLEX10K 칩에 합성한 QPSK 복조기의 속도는 약 2 (Mbps)의 전송속도를 가지며, ASIC으로 구현시에는 CPLD 속도의 5-6배 이상의 고속화가 가능하다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.361-364
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• 2002

In this paper, we consider the problem of CLB based CPLD technology mapping for power minimization in combinational circuit. The problem has been previously proved to be NP-hard, and hence we present an efficient heuristic algorithm for it. The main idea of our algorithm is to exploit the "cut enumeration" and "feasible cluster" technique to generate possible mapping solutions for the sub-circuit rooted at each node. However, for the consideration of both run time and memory space, only a fixed-number of solutions are selected and stored by our algorithm. To facilitate the selection process, a method that correctly calculates the estimated power consumption for each mapped sub-circuit is developed. The experimental results show that our approach is shown a decrease of 30.5% compared with DDMAP and that of 15.63% for TEMPLA in the Power consumption.

• Ocean Systems Engineering
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• 제7권1호
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• pp.53-74
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• 2017

Ship shaped FPSO (Floating Production, Storage and Offloading) units are the most commonly used floating production units to extract hydrocarbons from reservoirs under the seabed. These structures are usually much larger than general cargo ships and have their natural frequency outside the wave frequency range. This results in the response to first order wave forces acting on the hull to be negligible. However, second order difference frequency forces start to significantly impact the motions of the structure. When the difference frequency between wave components matches the roll natural frequency, the structure experiences a significant roll motion which is also termed as second order roll. This paper describes the theory and numerical implementation behind the calculation of second order forces and motions of any general floating structure subjected to waves. The numerical implementation is validated in zero speed case against the commercial code OrcaFlex. The paper also describes in detail the popular approximations used to simplify the computation of second order forces and provides a discussion on the limitations of each approximation.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권3호
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• pp.122-131
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• 2003

In this study, some characteristics of conductive and non-conductive adhesive inter-connections are derived, based on data from literature and own projects. Assembly of flip chip on flex is taken as a carrier. Potential failure mechanisms of adhesive interconnections reported in literature are reviewed. Some methods that can be used to evaluate the quality of adhesive interconnections and to evaluate their aging behavior are given. Possible finite element simulation approaches are introduced and the required critical materials properties are summarized. Response to temperature and moisture, resistance to reflow soldering and resistance to rapid change in temperature and humidity are elaborated. The effect of post cure during accelerated testing is discussed. This study shows that only a combined approach using finite element simulations, and use of appropriate experimental evaluation methods can result in revealing, understanding and quantifying the complex degradation mechanisms of adhesive interconnections during aging.

• Journal of Multimedia Information System
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• 제4권2호
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• pp.93-98
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• 2017

A new cultivation diary system based on environment sensor data and Web 2.0 with Flex is suggested, to improve the previous system using the subjective data of cultivators. The proposed system is designed by applying an object-oriented model called mini-architecture, in order to enhance the reliability of software as well as promote stability to overall system design. The environment sensor data such as temperature and humidity are used to develop the new reliable diary. Also, an active interface based on Web 2.0 and Android as the user GUI are implemented to maximize the convenience while recording the cultivation diary. The result of the performance evaluation shows that the data from sensors has 99.1% of correlation with that of analogue.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.287-288
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• 2007

This paper is for a Real-time Active Control System to operate a boiler. By sensing of flame we wanted to get status of a furnace as many as possible, like load, efficiency, and/or amount of pollutant. These data can be used to make optimal running point by controlling the ratio of air and fuel. So the last object is to make a closed actual control loop from optical head to valve controllers. The first job was to design and to develop a optical data acquisition system. including optical sensor module. And we gathered flame data in variable situations for taking the trend of flame against burning environment. Currently we are developing a general system model, designing some control strategy and testing this active control system.