• Journal of Communications and Networks
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• 제11권3호
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• pp.229-239
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• 2009

Orthogonal frequency division multiplexing (OFDM) has been adopted as a standard for various high data rate wireless communication systems due to the spectral bandwidth efficiency, robustness to frequency selective fading channels, etc. However, implementation of the OFDM system entails several difficulties. One of the major drawbacks is the high peak-to-average power ratio (PAPR), which results in intercarrier interference, high out-of-band radiation, and bit error rate performance degradation, mainly due to the nonlinearity of the high power amplifier. This paper reviews the conventional PAPR reduction schemes and their modifications for achieving the low computational complexity required for practical implementation in wireless communication systems.

• 한국실천공학교육학회논문지
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• 제1권1호
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• pp.13-18
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• 2009

본 논문에서는 지역 산업체를 대상으로 공학교육의 실태를 분석하여 수요지향적 공학교육을 위한 개선방안을 마련하고자 한다. 이를 위하여 공학교육 실무인재양성 교육프로그램인 캡스톤디자인, 현장실습, 주문식 인력양성을 주요 주제로 선정하여 서남권 지역산업체 임직원 대상 산학협동 교육프로그램 운영 실태를 조사하였다. 조사 결과, 서남권 지역산업체 대부분이 산학협동 교육프로그램 운영 경험이 미진하였다. 또한, 현장실습 추진 경험이 있는 산업체에서는 향후 추진계획에 유보적 입장을 보인 반면, 캡스톤디자인 경우 참여의사가 다소 있어 산학협동 교육프로그램별로 실행 모델이 마련되어야 할 것이다. 향후 지역전략 산업 기반 수요지향적 공학교육프로그램 운영을 위한 개선 방안을 마련하고자 한다.

• 초등상담연구
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• 제6권1호
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• pp.95-116
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• 2007

This thesis is aimed to understand when and how elementary teachers scold their students and to explore any common psychological factors shown in the process. In order to produce the meaningful results of the research, applied is experience-based analysing method which expectedly leads to discovering psychological cause and effect occurring when school teachers scold students. 11 teachers of elementary school, including me the author, have joined as co-researchers to solve the next two issues and I made guidelines for the analysis. Given that co-researchers are locally scattered, they were grouped into three and in the mean time, analysis on scolding during 4 meeting sessions were made. The results of research problems are as follows. First issue: What common psychological factors exist in when and how teachers scold students? Common factors in 'when' part include three cases: teachers discovering the factors hindering student's desirable growth, noticing the class rules and peaceful communities are broken, or experiencing humiliating remarks and annoying behaviors and In "how' part, on the other hand, teachers speak up in a stronger voice or raise their tone to point out student's wrongdoing and give students a stoic and fierce look. Second issue: What psychological development takes place in scolding? Teachers who participated in this scolding experiment have experienced' feeling responsible and upset'. Feeling responsible is highly likely to be interpreted to result from the idea that teachers supposedly support students to grow into well-functional person in society. Meanwhile, feeling upset or even humiliated is caused by the frustration when they find their authority and dignity Ignored and damaged. The phases teachers go through during the scolding are: recognizing scold-inviting situation-> interpreting clues deserving enough to scold-> being aroused into the feelings-> deciding how to respond-> executing decision-> dealing with emotion. This thesis has distinctive qualities from existing ones in that the research focuses on agonies and conflicts faced with school teachers in class. On top of that, it is noted that this thesis meaningfully enables to realize teachers' psychological mechanism activated from scolding and to provide teachers with opportunities to see themselves more proper perspectives. However, there still remains some reservation since I had rather short period of time to collect data and we, co-researchers, had meeting sessions. To compensate for the possible shortcomings shown in this thesis, further research is expected to be followed to perform a practical analysis.

• 한국전자파학회논문지
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• 제17권6호
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• pp.562-573
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• 2006

직교 주파수 다중 전송 방식 또는 다중 반송파 전송 방식은 첨두대 평균 전력비를 감소하는 것이 요구된다. 또한, 부분 전송열의 부가 전송 문제를 제거하는 것이 필요하다. 따라서, 본 논문에서는 다중 신호로 사용하기 위한 부반송파는 전적으로 첨두대 평균 전력비의 감소에만 사용하는 것으로 한 부분 전송 감소열에 의한 새로운 방식을 제안한다. 즉, 톤 예약 기법에서 사용한 빠른 알고리즘 또는 Convex 최적화 대신에 부분 전송열의 최적화를 약간 수정하여 사용한다. 모의 실험 결과 데이터율 손실이 5 %에서 톤 예약의 반복 횟수를 10으로 하면 제안된 방법 이 M=2, 4, 8(M은 부분 전송 감소열 분할 수)에서 각각 3.2 dB, 3.4 dB, 3.6 dB 개선된다. 그러나, 데이터율 손실이 20 %에서 톤 예약 방법에 비하여 3.4 dB, 3.1 dB, 2.2 dB 떨어진다. 따라서, 데이터율 손실을 적게 할 경우에는 제안된 방법이 M=2에서 톤 예약 방법에 비하여 계산량과 PAPR 저감 능력면에서 우수한 방법이다.