• Archives of Plastic Surgery
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• 제39권3호
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• pp.238-243
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• 2012

Background : The publication rate of presentations at medical international meetings has ranged from 11% to 78% with an average of 45%. To date, there are no studies about the final rate of publications at scientific meetings associated with plastic surgery from Korea. The present authors investigated the publication rate among the presentations at meetings associated with plastic surgery. Methods : The titles and authors of the abstracts from oral and poster presentations were collected from the program books of the Congress of the Korean Society of Plastic and Reconstructive Surgeons (CKSPRS) for 2005 to 2007 (58th-63rd). All of the abstracts presented were searched for using PubMed, KoreaMed, KMbase, and Google Scholar. The titles, key words from the titles, and the authors' names were then entered in database programs. The parameters reviewed included the publication rate, type of presentation including running time, affiliation, subspecialty, time to publication, and publication journal. Results : A total of 1,176 abstracts presented at the CKSPRS from 2005 to 2007 were evaluated. 38.7% of the abstracts, of which oral presentations accounted for 41.0% and poster presentations 34.8%, were published as full papers. The mean time to publication was 15.04 months. Among journals of publication, the Journal of the Korean Society of Plastic and Reconstructive Surgeons was most used. Conclusions : Brilliant ideas and innovative approaches are being discussed at CKSPRS. The 38.7% publication rate found from this research appeared a bit lower than the average rate of medical meetings. If these valuable presentations are not available as full papers, the research would be a waste of time and effort.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 추계종합학술대회
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• pp.520-524
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• 1999

임팩트이온화율은 낮은 전자에너지에서는 이방성이지만, 임팩트이온화가 자주 발생하는 높은 에너지 영역에서는 등방성이 된다. 본 연구에서는 300K와 77K에서의 임팩트이온화율을 계산하기 위하여 의사포텐셜 방법으로 구한 full 에너지 밴드 구조와 페르미의 황금법칙 군 사용하였다. 계산된 임팩트이온화율은 수정된 Keldysh공식을 사용하여 표현되었다. GaAs 임팩트이온화 모델의 타당성을 고찰하기 위해 Monte Carlo simulator를 제작하여 300K와 77K에서의 임팩트이온화 계수를 구하여 비교하였다 시뮬레이션 결과, 300K에서 임팩트이온화 과정의 이방성특성이 관찰되었지만, 77K에서는 거의 임팩트이온화 계수가 일정함을 입증하였다. 특히, 77K에서 <110>방향을 따라 적용된 전계에서는 이방성특성이 나타남을 입증하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.3887-3907
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• 2015

This paper introduces a full duplex single secondary user multiple-input multiple-output (FD-SSU-MIMO) cognitive radio network, where secondary user (SU) opportunistically accesses the authorized spectrum unoccupied by primary user (PU) and transmits data based on FD-MIMO mode. Then we study the network achievable average sum-rate maximization problem under sum transmit power budget constraint at SU communication nodes. In order to solve the trade-off problem between SU's sensing time and data transmission time based on opportunistic spectrum access (OSA) and the power allocation problem based on FD-MIMO transmit mode, we propose a simple trisection algorithm to obtain the optimal sensing time and apply an alternating optimization (AO) algorithm to tackle the FD-MIMO based network achievable sum-rate maximization problem. Simulation results show that our proposed sensing time optimization and AO-based optimal power allocation strategies obtain a higher achievable average sum-rate than sequential convex approximations for matrix-variable programming (SCAMP)-based power allocation for the FD transmission mode, as well as equal power allocation for the half duplex (HD) transmission mode.

• ETRI Journal
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• 제46권3호
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• pp.446-460
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• 2024

In this paper, we mathematically investigate a downlink non-orthogonal multiple access (NOMA) system for short-packet communications (SPC) in which the near users are used as full-duplex (FD) relays to forward intended signals from the source to a far user. In addition, partial relay selection is employed to enhance the performance of the FD relays under the impact of imperfect interference cancellation. At the far user, selection combining (SC) or maximal ratio combining (MRC) is employed to combine the signals received from the source and the selected FD relay. The analytical expressions for the average block error rate (BLER) of two users over flat Rayleigh fading channels are derived. Furthermore, closed-form asymptotic expressions of the average BLERs at the near and far users in high signal-to-noise ratio (SNR) regimes are obtained. The numerical results show that the analytical BLERs of the near user and far user closely match the simulation results.

• ETRI Journal
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• 제42권1호
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• pp.17-25
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• 2020

Multiple-input multiple-output systems can achieve a full sum rate (SR) via full duplex (FD). However, its performance is degraded by self-interference (SI) that occurs between the transmitter and receiver at the same node and thus is constrained by error floors. Conversely, half duplex (HD) can avoid the SI albeit at lower spectral efficiency, and the slope of its error curve is determined by the diversity order. In this study, a link selection scheme based on switching between FD and HD is examined as a simple method to improve the bit error rate (BER) performance of FD systems. In the proposed link selection algorithm, either FD or HD is selected based on the received minimum distance and signal-to-interference plus noise ratio. Simulation results indicate that the proposed hybrid FD/HD switching system offers significant BER performance improvement when compared with that of the conventional FD and FD based on only the received minimum distance under the same fixed SR. Under relatively sufficient SI cancellation, it is demonstrated to outperform the HD with a diversity advantage in low and medium signal-to-noise ratio region.

• 대한전자공학회논문지TC
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• 제46권4호
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• pp.70-76
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• 2009

본 논문에서는 ABAB 형 준직교 시공간 부호(Quasi-Orthogonal Space-Time Block Code; QOSTBC)에 사용되는 전처리 과정을 설계하는 조건을 제안하였다. 본 논문에서 제안한 설계 조건은 최대 다이버시티 및 최대 전송율(Full Diversity and Full Rate; FDFR), 단일 심볼 복호 능력, 향상된 부호 이득을 얻을 수 있는 방법을 제공한다. 또한 본 논문에서는 제안된 설계 조건을 이용하여 개선된 ABAB 형 QOSTBC를 설계하였다. 이 QOSTBC는 기존에 Dalton이 제안했던 ABAB 형 QOSTBC 부호 보다 뛰어난 성능을 가질 뿐 아니라, 동일하게 FDFR을 충족하며, PAM 신호 성좌가 사용되는 경우, 단일 심볼 복호가 가능하다.

• Journal of Preventive Medicine and Public Health
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• 제42권5호
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• pp.293-297
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• 2009

Objectives : To evaluate the impact of the workplace smoking ban in South Korea, where the male smoking rate is high (57%), on smoking behavior and secondhand smoke exposure. Methods : A workplace smoking ban legislation implemented in April 2003 requires offices, meeting rooms, and lobbies located in larger than 3,000 square meter buildings (or 2,000 square meter multipurpose buildings) should be smoke free. A representative cross-sectional survey, the third wave (2005) of health supplements in the National Health Nutrition Survey of South Korea, was used to measure the impact of the 2003 workplace smoking ban implementation on smoking behavior. It contained 3,122 observations of adults 20 to 65 years old (excluding selfemployed and non-working populations). A multivariate statistical model was used. The self-reported workplace smoking ban policy (full workplace ban, partial workplace ban, and no workplace ban) was used as the key measure. Results : A full workplace smoking ban reduced the current smoking rate by 6.4 percentage points among all workers and also decreased the average daily consumption among smokers by 3.7 cigarettes relative to no smoking ban. Secondhand smoke showed a dramatic decrease of 86 percent (= -1.74/2.03)from the sample mean for full workplace ban. However, public anti-smoking campaign did not show any significant impact on smoking behavior. Conclusions : The full workplace ban policy is effective in South Korea. Male group showed bigger impact of smoking ban policy than female group. The public antismoking campaign did not show any effectiveness.

• 디지털융복합연구
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• 제10권4호
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• pp.207-215
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• 2012

본 논문에서는 무선 모바일 애드 혹 네트워크상에서 스트리밍 미디어 서비스 향상을 위한 프록시 기반 캐싱 최적화 기법을 제안한다. 제안된 기법은 WLAN상에서 미디어 서버와 노드들 간의 통신을 위해 프록시를 사용하며, 프록시는 무선 엑세스 포인터 근처에 설치한다. 그리고 캐싱 최적화가 수행되도록 NFCO(non-full cache optimization)과 CFO(cache full optimization)기법을 제안한다. NFCO와 CFO는 프록시에서 스트리밍이 수행될 때 캐시의 성능을 최적화하기 위해 사용된다. 제안된 기법의 성능을 알아보기 위하여 본 논문에서는 제안된 기법과 서버-중심 스트리밍 기법, 그리고 전송율 왜곡 스트리밍 기법과의 성능을 비교 분석하였다. 그 결과 제안된 기법이 서버-중심 스트리밍 기법과 전송율 왜곡 스트리밍 기법에 비해서 최적화 성능이 우수함을 알게 되었다.

• 한국통신학회논문지
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• 제30권4A호
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• pp.282-287
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• 2005

송신다이버시티 시스템에 사용되는 시공간 블록부호(space time block code)는 송신안테나가 2개보다 많은 경우 최대 전송률과 최대 다이버시티 이득을 동시에 제공할 수 없다. 송신안테나가 4개인 경우 최대 전송률을 제공하면서 간섭을 최소화하는 준직교성 블록부호가 있다. 최근에는 준직교성에 의해 발생하는 블록부호의 간섭을 제거하는 단순상관제거 알고리즘이 제안되어 최대전송률과 최대 다이버시티 이득을 얻을 수 있게 되었다. 본 논문에서는 신호의 전송전력을 다르게 할당하고 수신단에서의 빼기 연산에 의한 간단한 간섭제거로 잡음 증가 없이 성능을 개선하는 복호화 과정을 제안한다.

• 한국통신학회논문지
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• 제9권1호
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• pp.1-10
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• 1984

時分割多重化方式에 의한 Telemetry用 PCM encoder를 塔載型遠幅測定에 適合하도록 國産化開發硏究를 追究하였다. Program switch에 의하여 選擇되는 PCM encoder의 analog人力채널은 0~64word/frame($\pm$5V full scale), discrete人力은 0~30bit(5V$\pm$1V or 0V$\pm$1V dc)이며 bit rate는 70 및 140Kbit/sec, 分解能力은 8~12bit/word를 選擇할 수 있다. 그리고 filtered output code는 5次Bessel型LPF($f_{c}$=100kHz)를 통한 NRZ-L 및 Bi$\phi$=S이며 PCM encoder의 시스템誤差는 full scale에 대하여 最大 $\pm$0.2%이다.