• 한국통신학회논문지
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• 제12권4호
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• pp.335-346
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• 1987

光纖維 內에서 後方散亂을 일으키는 주된 要因은 光纖維 構成物質의 密度 不均一과 코어變化에 의해 發生하는 Rayleigh散亂이다. 이 後方散亂에 의해 發生하는 後方散亂 光電力은 optical time domain reflectometer로 檢出할 수 있다. O.T.D.R. 시스템으로 檢出한 後方散亂 光電力은 光纖維 길이에 따른 電力減衰情報와 光纖維 코어의 直徑變化에 관한 情報들을 포함하고 있다 따라서 本 論文에서는 avalanche photodiode의 飽和狀態를 除去할 수 있는 2$\times$2fiber directional coupler와 S/N比를 增加시키는 gated integrato와 timing control circuit를 첨가하여 O.T.D.R. 시스템을 構成하였으며, 構成한 O.T.D.R 시스템으로 後方散亂 光電力을 檢出하여 光纖維 內 코어의 直徑變化를 測定하였다.

• 미생물학회지
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• 제27권2호
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• pp.139-146
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• 1989

담수상태의 논토양에 처리한 유기인계 살충제 diazinon의분해기작과 그 분해산물에 대하여 조사하였다. 항온조건($30^{\circ}C$)하에서 살균토양에 비하여 비살균토양에서의 diazinon 분해가 보다 빠르게 일어남으로써 담수토양내 diazinon 분해에 미생물의 대사활동이 매우 종요한 것으로 나타났는데, 비살균토양내 diazinon의 반감기는 약 2일이엇고 항온반응 7일만에 95% 이상의 분해가 이루어졌다. 또한 diazinon 분해기간 중 미생물 개체수와 아울러 토양내 monoxygenase 및 esterase 활성의 증가가 이루어졌으며 이는 토양내 diazinon 처리가 이 약제의 분해와 관련된 미생물학적 요인의 생장 또는 활성을 촉진시키고 있음을 보여준다. 이와 관련하여 담수토양내 diazinon 분해산물로서 esterase 작용에 의한 2-isopropyl-6-methyl-4-hydroxy pyrimidine 이외에 monooxygenase에 의한 diazoxon과 hydroxydiazinon, 그리고 sulfotep 등이 mass spectrometry에 의하여 확인되었다.

• 한국통신학회논문지
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• 제8권4호
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• pp.164-171
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• 1983

본 논문에서는 비교적 짧은 계단형 멀티모우드 광섬유를 이용하여 여러 정보의 채널을 전송하는 광멀티플렉싱 기술인 각도분할방식(ADM: Angular Division Multiplexing)에 대해 논하였다. 평면파 입력에 대한 광섬유 내의 모우드 결합과 출력 파워 분포가 계산되었으며 시스템의 혼신도 결정이 제시되었다. 모우드 결합 하에서 광섬유의 길이와 입력조건에 따른 펄스폭이 평면 도파판과 광섬유에 대해 비교, 계산되었다. NA(Numerical Aperture)아래의 입력각에 대한 각도폭은 입력각이 클수록 줄어들었으며 출력은 입력각에 파워가 집중된 환형으로 나타났으며 이는 ADM시스템의 중요한 요인이 되었다.

• 약학회지
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• 제8권3호
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• pp.80-84
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• 1964

The purpose of this investigation is to observe tha variation of vitamin $B_{12}$, nicotinic acid and folic acid contents in relation to the growing years of Panax Ginseng roots. The contents of the vitamins were estiamted microbiologically with Lactobacillus leichmannii, Lactobacillus arabinosus and Streptococcus faecalis, respectively. It is found that the content of vitamin $B_{12}$ in Panax Ginseng roots somewhat increases according to their growing years except 3-year-old roots. It is probable that the lower content in these roots should be due to the cultivating soil. The content of nicotinic acid in all the roots is not significantly different. The result of paper chromatography using the concentrated extract of the roots suggests that there exists some other substance besides nicotinic acid and nicotinamide, of which Rf value is 0.5 in comparison with the Rf 0.75 of nicotinic acid and nicotinamide. It is thought that this substance stimulate the growth of L. arabinosus. The content of folic acid is significantly different. The content level is the highest in the 4-year-old roots and the lowest in the 6-year-old roots.

• The Journal of Asian Finance, Economics and Business
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• 제7권11호
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• pp.779-788
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• 2020

Commercial banks play an important role as the main source of funding in the transition process of Vietnam as a market economy. As a result, enhancing the efficiency and productivity of Vietnamese banks can decrease the lending cost for individuals and enterprises. This study is to measure and analyze the productivity change of Vietnamese banking system in different ownership cohorts and sources of this change during the period of restructuring (2011-2019). The Hicks-Moorsteen total factor productivity index is utilised to measure the productivity change and to identify the sources of this change. For an empirical analysis, the data of 28 Vietnamese commercial banks from 2011 to 2018 is collected from their financial statements including balance sheets and income statements. The results show an increase of Vietnamese bank productivity due to the technological progress. While foreign and joint-venture banks are the most advanced cohort, state-owned banks have the lowest rate of productivity growth. The restructuring program negatively impacts scale efficiency and this measure attributes to a decline in the overall efficiency of the banks. We also found that state-owned commercial banks are the most efficient group in the sense that they can achieve the maximal level of revenue from a given amount of expense.

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.267-273
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• 2020

With the strong growth of social networking sites such as Facebook in recent years, the potential of exploiting customers on Facebook is increasing. Presently, trading activities on Facebook is rapidly developing. Therefore, businesses have become increasingly competitive when selling products on Facebook, so as to retain customers as well as to satisfy customer, which is of paramount importance. This study was conducted to assess the factors affecting the satisfaction of individual customers in Vietnam when buying goods on Facebook. This study uses multivariate analysis techniques (Confirmatory Factor Analysis, Structural Equation Modeling) to determine the factors affecting customer satisfaction when buying goods on Facebook. Research results from 268 individual customers in Vietnam indicated trust and convenience are the two important factors related to customer satisfaction when buying goods on Facebook. Customer satisfaction is the result of consumer experience throughout the different stages of purchase. The more the shopping experience, the more the customers are satisfied when buying products. The price and products do not affect customer satisfaction (prices are easy to compare and products are easily understood on the Internet; hence, these two factors are not considered as determinants of customer satisfaction). Furthermore, this study provides recommendations to improve customer satisfaction.

• 미생물학회지
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• 제27권3호
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• pp.285-290
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• 1989

한국에서 분리한 비유황 광합성 세균 Rhodospirillum rubrm KS-301 생장에 대하여 논 잡초제로 널리 쓰이는 butachlor(제품명 Machete)의 영향을 본 것이다. 실제 논에서 사용되고 있는 농노인 $10^{-3}$에서도 균의 생장은 이루어졌고 $10^{-2}$M의 농도에서 억제되어 다른 생물체보다 높은 저항력을 가지는 것으로 나타났다. 더욱이 pyruvate를 탄소원으로 하여 질소고정 상태로 배양했을 때 butachlor를 처리한 실험군에서 미약하나마 오히려 생장이 촉진되었다. (1%). 전자현미경으로 내부막조직을 관찰한 결과 Rhodospirillum rubrum의 전형적인 vesicular type이 tubular type으로 변형된 것으로 보아 제초제의 흡수가 간접 확인되었다. 또한 pH가 알칼리 조건일 때 질소고정상태에서 균생장에 대한 제초제의 저해력이 떨어지는 것으로 나타났다.

• 대한인간공학회지
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• 제16권2호
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• pp.39-59
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• 1997

With a view to providing basic data for designing male's and female's clothes, healthy males and females(five each) were exposed to three different environmental temperature($20{\pm}1.0^{\circ}C$, $28{\pm}1.0^{\circ}C$, $32{\pm}1.0^{\circ}C$) in the nude. Their adaptation of skin temperature, physiological responses( rectal temperature, blood pressure, pulse rates) and psychological reactions(thermal, comfort and perceptive sweaty sensations) were analyzed as follows; The subjects's skin temperature had a similar look of adaptation, but the stability of skin temperature differed at tha $20{\pm}1.0^{\circ}C$ and at the $28{\pm}1.0^{\circ}C$ Males had higher skin temperature at three environmental temperatures, but females showed a higher temperature change at the $20{\pm}1.0^{\circ}C$ and $28{\pm}1.0^{\circ}C$ and males at the$32{\pm}1.0^{\circ}C$ Thus females were more resistant to the cold, while males were more resistant to the heat. As environmental temperature increased, rectal temperature and pulse rates also grew up. Females turned higher in rectal temperature and lower in blood pressure, but both sexes had a normal range of physiological reactions. Even though three environmental temperatures were same changes in thermal sensation at $28{\pm}1.0^{\circ}C$and in perceptive sweat sensation at $32{\pm}1.0^{\circ}C$, two sexes had the same response in comfort sensation at the three environmental temperatures.

• Steel and Composite Structures
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• 제12권3호
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• pp.231-248
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• 2012

This research aims to investigate the structural behavior of concentrically braced frames after element loss by performing nonlinear static and dynamic analyses such as Time History Analysis (THA), Pushdown Analysis (PDA), Vertical Incremental Dynamic Analyses (VIDA) and Performance-Based Analysis (PBA). Such analyses are to assess the potential and capacity of this structural system for occurrence of progressive collapse. Besides, by determining the Failure Overload Factors (FOFs) and associated failure modes, it is possible to relate the results of various types of analysis in order to save the analysis time and effort. Analysis results showed that while VIDA and PBA according to FEMA 356 are mostly similar in detecting failure mode and FOFs, the Pushdown Overload Factors (PDOFs) differ from others at most to the rate of 23%. Furthermore, by sensitivity analysis it was observed that among the investigated structures, the eight-story frame had the most FOF. Finally, in this research the trend of FOF and the FOF to critical member capacity ratio for the plane split-X braced frames were introduced as a function of the number of frame stories.

• 한국통신학회논문지
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• 제13권1호
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• pp.85-93
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• 1988

원거리 통신망의 디지탈화가 급격히 이루어지고 있다. 이들 디지털 시스템에는 경제성을 고려하여 비틀어 꼰 금속도체쌍을 다중화시켜 사용한다. 이와 같이 다중화된 케이블 뭉치를 사용하는 관계로 전송신호 상호간에 누화간섭이 발생한다. 따라서 본 논문에서는 다중쌍 내 전송신호가 누화간섭을 계산하는 방법을 연구해서 누화간섭전력에 대한 시스템의 전송오차마진을 분석했다. 마지막으로 1.544Mb/s와 2.048Mb/s PCM 시스템의 상호누화잡음훼손도를 계산해서 동일 케이블내 혼용 방법을 제시하였다.