• 한국통신학회논문지
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• 제31권5A호
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• pp.484-492
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• 2006

다중부호 배직교 부호 변조(Multi-code biorthogonal code keying: MBCK)는 배직교(biorthogonal) 부호화기의 출력 코드워드를 합산하여 전송함으로 전송 신호의 크기가 일정하지 않기 때문에 고선형 증폭기의 사용을 요구한다. MBCK의 전송 신호의 크기를 일정하게 유지하도록 만드는 부호화 방안이 제안되어 있는데, 정 진폭 부호화에 사용된 잉여 비트들은 수신기에서 비트오율 성능 개선을 위해 사용될 수 있다. 본 논문에서는 정 진폭 부호화된 MBCK(MBCK with Constant Amplitude Coding:CA-MBCK)의 대역폭 효율을 개선시키기 위해 CA-MBCK와 쌍직교위상변조(Quadrature-Quadrature Phase Shift Keying:$Q^{2}PSK$)를 결합하는 방안을 제안한다. 제안된 시스템은 출력 신호의 크기를 일정하게 유지하며 백색 가우시안 잡음 환경에서 CA-MBCK와 동일한 비트오율 성능을 보이면서도 대역폭 효율은 개선되었다. 또한 CA-MBCK에서 정 진폭 부호화에 사용된 잉여 비트를 이용한 에러정정 알고리즘을 제안된 시스템에 적용하여 비트오율 성능이 개선됨을 모의실험을 통해 제시한다.

• 전자공학회논문지
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• 제52권1호
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• pp.24-31
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• 2015

코드워드의 인자로 M진 위상 편이 방식(M-ary phase shift keying, M-PSK)를 사용하는 차분 코드북은 Long term Evolution (LTE), LTE-Advanced (LTE-A) 그리고 WiMax 시스템 등에 제안된다. 인접하는 무선 채널의 시간 상관 특성에 의해 연속된 선부호화 행렬 내 양자화된 채널 정보는 천천히 변화된다. 이는 전체 무선 채널 공간을 양자화 하지 않고, 시간 상관 특성에 따른 채널 공간 내 일부분만을 양자화하여 피드백하기 때문에 기존과 동일한 크기의 코드북을 구성해도 가상적으로 보다 정확한 채널정보를 양자화할 수 있어 채널 용량이 증가하는 효과를 갖는다. 제안하는 코드북은 constant modulus, complexity reduction, 그리고 nested property와 같은 LTE release-8 코드북 특성을 갖는다. 또한 동 이즉 전송 특성을 갖기 때문에 상대적으로 저렴한 비선형 증폭기를 사용할 수 있어 가격의 제한을 받는 단말기 설계에도 이점을 갖는다. 컴퓨터 시뮬레이션을 통해 제안하는 차분 동 이득 전송 기술은 동일한 피드백 비트 수를 갖는 기존의 LTE-8 코드북보다 향상된 성능을 보인다.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-1
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• pp.29-31
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• 2003

People usually try to take in nutrition component which is necessary for physical growth, developing and maintaining the health through usually balanced dietary life. However in looking over the results of recent national nutrition survey, even if the nation’s average taking in nutrition condition is fairly good, considering the individual cases there has happened a problem about the balance of taking in nutrition due to the wrong dietary life. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.158.1-158.1
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• 2003

We report here the results on N-acetyl-N"-methylamide of oxazolidine (Ac-Oxa-NHMe) calculated using the ab initio molecular orbital method with the self-consistent reaction field (SCRF) theory at the HF level of theory with the 6-31 +G(d) basis set. The displacement of the $\gamma$-$CH_2$ group in proline ring by oxygen atom has affected the structure of proline, cis-trans equilibrium, and rotational barrier. The up-puckered structure is found to be prevalent for the trans conformers of the Oxa amide. (omitted)

• Journal of Advanced Marine Engineering and Technology
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• 제31권5호
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• pp.575-582
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• 2007

In this paper, a 100 Watt high power amplifier has been implemented and performed evaluation, which is operating at UHF band ($470\;{\sim}\;806\;MHz$) for Digital TV repeater. To achieve increase of bandwidth and high power capability, 3-way power combiner and divider of Wilkinson type was adopted. In order to measure the fabricated 100 Watt power amplifier, the estimation technique function which makes equivalent mask was used. As a result of the measurement, the existence of pilot signal is confirmed and the signal transmitted at the rated output power 100 Watt is brought out the flat feature through 6 MHz bandwidth. and it resulted that its value was less than -47 dB at the edge of radiation channel and less than -110 dB at more than 6 MHz position from channel edge.

• 한국통신학회논문지
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• 제31권7A호
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• pp.689-695
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• 2006

본 논문에서는 부정확한 채널 추정이 존재하는 상황에서 고차 변조 방식을 포함한 공조 다이버시티 기법의 정확한 비트 에러율 성능을 유도한다. 실험 및 성능 분석 시 채널 환경은 저속 시변 레일리 페이딩 환경을 가정한다. 기본적인 동조 다이버시티의 성능 유도 방식은 Moment Generating Function(MGF)를 이용하여 성능을 구하는 방법을 적용한다. 또한, 본 논문에서는 유용한 채널 추정의 영향을 성능 유도에 적용하기 위하여 기존의 유용한 가우시안 근사화 방식을 사용, 실효 잡음 (effective noise} 성분 및 부가 잡음을 정형화한다. 이 근사화 기법에 근거하여 M-QAM 및 M-PSK을 사용하는 공조 다이버시티에서의 평균 비트 오차율 성능은 신호 대 실효 잡음비의 함수로 계산된다. 모의 실험을 통한 검증 결과, 유도된 성능은 낮은 신호 대 잡음비 구간을 포함한 거의 모든 구간에서 높은 정확도를 갖는 것으로 판명되었다.

• 약학회지
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• 제59권5호
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• pp.222-229
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• 2015

Lithospermi radix, the dried roots of Litospermum erythrorhizon Sieboid et Zuccarini (Boraginaceae), has long been used to treat detoxification and inflammation. In this study, we isolated two main quinoid compounds, ${\beta}$-hydroxyisovalerylshikonin (1) and acetylshikonin (2) from L. erythrorhizon. As acetylshikonin is considered as a marker compound of L. erythrorhizon, a rapid analysis method for the simultaneous determination of quinoid compounds including 2 was also developed by HPLC (High Performance Liquid Chromatography) and validation of this analytical method. By the developed method, two quinoid marker compounds (${\beta}$-hydroxyisovalerylshikonin and acetylshikonin) were successfully quantified in 31 commercial samples which were collected from different regions. The contents were 0.20% (${\beta}$-hydroxyisovalerylshikonin) and 0.22% (acetylshikonin), respectively.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.160.2-160.2
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• 2003

When ginsenoside $R_{b1}$ and $R_{b2}$ were anaerobically incubated with human fecal microflora, these ginsenosides were metabolized to compound K. When ginsenoside $R_{g3}$ was anaerobically incubated with human fecal microflora, the ginsenoside $R_{g3}$ was metabolized it to ginsenoside $R_{h2}$. Among ginsenosides, compound K and 20(S)-ginsenoside $R_h2$ exhibited the most potent cyotoxicity against tumor cells: 50% cytotoxic concentrations of compound K in the media with and without fetal bovine serum (FBS) were 27.1 - 31.6 mM and0.1 - 0.6 mM, and those of 20(S)-ginsenoside $R_h2$ were 37.5 $\rightarrow$ 50 and 0.7 - 7.1 mM mM, respectively. (omitted)

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.200.1-200.1
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• 2003

Cephalotaxus koreana Nakai is an endemic species in Korea. The EtOH extract of leaf and branch from the plant showed potent antitumor activity in Teruhiro's method. The tumor volume inhibition ratio value is 25.2% with 20mg/kg in the BDF1 mouse injected LLC cell. We isolated one flavone, sciadopitysin (1), two flavone O-glycosides, quercetin 3-O-${\beta}$-D-glucuronide 6"-ethyl ester (2), apigenin 7-neohesperidoside (3) in comparison with literatures data. Compounds 1-3 showed stronger antitumor activity than Taxol used as positive control. The inhibition ratio values of compounds 1-3 is 34.9, 31.6, 34.0%, respectively, and Taxol is 27.0 % compared with control group.

• 약학회지
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• 제58권6호
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• pp.387-396
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• 2014

High Caffeinated Energy Drink (HCED) consumption among adolescents has been exponentially increasing. The intake of HCED may cause various side effects. However, studies regarding intake of HCED in adolescents have been rarely implemented in Korea. The purpose of this study was to investigate HCED consumption patterns among adolescents and prevalence of adverse effects from HCED consumption and to compare them between middle and high school students. The self-reported questionnaire with 31 questions was used to evaluate HCED consumption patterns and adverse effects. Among 792 students, 455 who had drunken HCED were included in the analysis. Nine (4.0%) Middle School Students (MSSs) and 11 (4.8%) High School Students (HSSs) responded that they did not know HCED, and 188 (83.6%) MSSs and 221 (96.1%) HSSs had heard that HCED contains high amount of caffeine. Seventy-four (36.8%) MSSs drank their first HCEDs from curiosity and 63 (31.3%) MSSs to stay awake while studying. However, 134 (61.2%) HSSs consumed their first HCEDs to keep awake while studying, and 57 (26.0%) HSSs from curiosity. Twenty-eight (12.5%) MSSs and 46 (20.3%) HSSs had increase in heart rate, 52 (23.2%) MSSs and 83 (36.4%) HSSs insomnia, and 8 (3.6%) MSSs and 18 (7.9%) HSSs hand and facial tremor. As shown in this study, HCED consumption among adolescents in Korea was high. Thus, Korean government should continuously focus its efforts to educate not only children and adolescents but also their parents for HCEDs in order to increase parents' awareness of HCEDs and conduct education regarding HCED intake at home above all.