• 전자공학회논문지SC
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• 제47권5호
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• pp.18-23
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• 2010

본 논문은 유발전위(evoked potential) 뇌파인 P300에 기반한 뇌-기계 인터페이스의 실시간 구현을 위한 효율적인 알고리즘을 제안한다. P300 뇌파는 외부 시각 자극이 인간의 의지와 일치할 경우, 100-300ms 부근에서 negative pick를 갖는 특성이 있다. 이러한 특성에 기초하여 P300 뇌파의 포텐셜(potential) 감소를 감지하여 인간의 의도를 역으로 추론할 수 있으며, 이를 뇌-기계 인터페이스에 활용할 수 있다. 연구에서 P300 뇌파는 인간의 두개골 외부에 부착된 전극을 통해 얻어졌으며, 시각적 자극으로는 2차원 알파벳 신호를 사용하였다. P300 뇌파의 포텐셜 감소 검출을 위하여 뇌파 포텐셜을 자극과 연계하여 확률적으로 모델링하였다. 확률적 모델은 피실험자가 의도하는 신호의 모델(target model)과 의도하지 않는 신호의 모델(non-target model)로 구성된다. 이러한 확률적 모델에 기반하여 피실험자의 의도를 추론하기 위해서 최우추정법(maximum likelihood estimation)을 사용하였다. 실험에는 신체 건강한 성인 남자 3명이 참가하였으며, 'A'와 'E' 실험에 대한 피실험자 k의 평균 성공률은 98%, 피실험자 j의 평균 성공률 90%, 그리고 피실험자 h의 성공률은 79.8%였다.

• 환경위생공학
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• 제9권2호
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• pp.1-7
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• 1994

Rainwater was collected in Seoul area from January 1991 to December 1993 (over 3years) and by the analysis of the chemical components contained in rainwater, investigated the components that effect on rainwater pH Through the above studies the following conclusions were obtained. 1) Method for Averaging pH Volume weighted method is considered to be acceptable providing that precipitation is measured at the same time when the samples are taken, without precipitation data a simple averaging method should be the next choice. 2) Annual average rainwater pH was 4.98 in 1991, 4.80 in 1992, 4.67 in 1993, measurement range was 3.6-8.1. 3) In the relationship between rainwater pH and rainfall amounts rainwater pH for light rain(<15mm rainfall) was existent in the wide range(pH 4-7), but for heavy rain was corresponded to the annual average values. 4) Annual frequency of pH was Birrndat the frequency($\gamma $) between the density of the [$H^{+}$] and pH in the rainwater(over 3years ), $NO_{3}^{-}$ was excellent and the obtained results was 0.62 in 1992. Also In the correlation coefficient($\gamma $) according to the pH range $SO_{4}^{2-}, NO_{3}^{-}$, were 0.85 ,0.68 at 3.6 $Cl^-$ was 0.99(1993). At 4.1$NO_{3}^{-}(\gamma=0.48)$ in 1992, SO_4^{2-}($\gamma$=0.54), $NO_{3}^{-}(\gamma$=0.72), $Cl^- (\gamma$=0.49) in 1993. 6) pH values gradually increased with increase in $Ca^{2+}/SO_{4}^{2-}$.

• 정보처리학회논문지A
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• 제12A권6호
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• pp.493-498
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• 2005

P2P 서비스는 인터넷 상에서 서버를 거치지 않고 정보를 찾는 사람과 정보를 가진 사람의 컴퓨터간의 직접적인 연결을 통해 다양한 정보를 공유할 수 있는 방식으로, 파일의 자유로운 교환을 위한 방법으로 많은 인기를 얻고 있다. 그러나 P2P 파일 공유 시스템에서 서비스를 이용하는 모든 사용자들은 동등한 접근 권한으로 자유롭게 여러 사용자들의 공유 파일을 이용할 수 있기 때문에, 자신의 파일에 대한 공유 없이 다른 사용자들의 공유 파일을 다운로드만 하는 "free riding" 문제가 빈번하게 발생하고 있으며, 바이러스나 웜을 포함한 파일을 공유하거나 실제내용과 다른 제목을 가지는 파일을 공유하는 사용자라 하더라도 제한 없이 파일 공유 서비스를 이용할 수 있다. 이에 본 논문에서는 파일 공유서비스를 이용하는 사용자들의 신뢰도를 나타낼 수 있는 평판(Reputation) 정보를 이용하여 빈번한 다운로드를 행하는 "free rider"의 접근을 제한하고, 정상적인 실행이 되지 않는 파일을 공유한 사용자들에 대해서도 다른 사용자들의 공유 파일에 대한 사용을 제한하고자 한다.

• 정보처리학회논문지B
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• 제12B권7호
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• pp.783-788
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• 2005

최근 P2P(Peer-to-Peer) 네트워크를 VOD(Video On Demand) 스트리밍에 적용하는 연구들이 활발히 발표되고 있다. VOD 스트리밍에 관한 기존 연구를 살펴보면, 클라이언트의 새로운 서비스 요청시, 초기 지연을 없애는 전송과 서비스 기각률을 최소화하는 것을 가장 중요한 목표로 삼고 있다. 본 논문은 이들 목표를 달성하기 위해서 P2P 기반의 멀티캐스팅 트리를 이용해서 효과적으로 비디오 스트리밍(streaming)을 제공하는 새로운 방법, 일명 포워드캐스트(ForwardCast)를 제안한다. 제안된 방법은, 새로운 클라이언트는 초기 지연없이(zero-delay) 비디오를 전달받고, 경우에 따라서는 데이터의 앞, 뒤 부분을 동시에 전송받기도 한다. 실험 결과, 포워드캐스트는 기존 연구에 비해서 서버 부하를 증가시키지 않으면서 기각률을 낮출 수 있었다.

• 약학회지
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• 제28권5호
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• pp.293-297
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• 1984

The pKa' of tranylcypromine was determined by potentiometric titration and ultraviolet spectrophotometric method and found to be 8.08 and 8.15, respectively. The Papp of tranylcypromine between n-heptane and aqueous buffer solution was measured to be 0.90 at pH 7.48 and 4.50 for Pm. The pKa' of tranylcypromine obtained by means of the partition method was 8.13.

• Journal of information and communication convergence engineering
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• 제5권4호
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• pp.324-327
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• 2007

In this paper, the p-n junction depth with nondestructive method by using scanning electron microscopy (SEM) is determined and conformed. By measuring the critical short circuit current on the p-n junction which induced by electron beam and calculating generation range, the diffusion depth can be obtained. It can be seen that values destructively measured by constant angle lapping and nondestructively by this study almost concur. As this result, it is purposed that diffusion depth of p-n junction can be easily measured by nondestruction. This nondestructive method can be recommended highly to the industrial analysis.

• Journal of applied mathematics & informatics
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• 제29권3_4호
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• pp.847-858
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• 2011

We make use of the simplified Hirota's bilinear method with computer symbolic computation to study a variety of coupled potential KdV (pKdV) equations. Each coupled equation is completely integrable and gives multiple soliton solutions and multiple singular soliton solutions. The phase shifts for all coupled pKdV equations are identical whereas the coefficients of the obtained solitons are not identical. The four coupled pKdV equations are resonance free.

• 제어로봇시스템학회논문지
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• 제12권12호
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• pp.1173-1177
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• 2006

Using an inner P controller, a tuning rule useful for processes with wide ratios of time delay over time constant is proposed. Internal model control method and pole assignment method are utilized. It can be used for processes with wide range of the ratio of time delay to time constant without incovenience to choose different tuning rules.

• Toxicological Research
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• 제18권1호
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• pp.59-64
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• 2002

Substantial evidences have been accumulated about the hormone-like effects of exogenous substances such as pesticides and industrial chemicals during past years. The effects of these substances on the endocrine system are believed to be either enhancing or reducing of various endocrine action. It is necessary to identify putative causal agents by the batter system and to assess their ability to disrupt the endocrine system. A variety of in vitro and In vivo approaches have been used to determine the androgenic effects of environmental chemicals. To establish the method for assessment of the putative endocrine disruptors with androgenic activity, we carried out the cell proliferation assay by MTS method after treatment with the various concentration of testosterone in LNCaP cells (human prostatic cancer cell line) and also observed the expression of androgen-related genes by quantitative RT-PCR. In the cell proliferation assay, the results showed that the grouth of LNCaP cells increased within level of at least 10pM testosterone. We measured by quantitative RT-PCR method on the effects of testosterone on mRNA expression of androgen receptor (AR), prostate-specific antigen (PSA), bone morphogenetic protein (BMP) and BMP receptor (BMPR) In LNCaP cells. The results demonstrated that mRNA expression of PSA and BMPR-IB was observed differently within level of at least 0.01 pM testosterone compared with non-treated control. These observations suggest that the detection of PSA and BMPR-IB mRNA by the quantitative RT-PCR in LNCaP cells is very sensitive method to identify the endocrine disruptors to have the androgenic effects.

• 한국환경과학회지
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• 제4권5호
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• pp.469-479
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• 1995

The increase of population and industrial activities had brought into eutrophication in the Nakdong river. A remarkable acceleration of eutrophication brought about serious problems for water supply. Therefore, for the purpose of conservation of water quality in the Nakdong river it is necessary to control nutrients. MBOD method was use to evaluate algal growth limiting factor and algal growth potential in the Nakdong river from June to August 1994. The modified biochemical oxygen demand(MBOD) depends on the amount of available inorganic nutrient and organic substrate during 5 day incubation in the dark at 2$0^{\circ}C$. The MBOD assay depends on inorganic nutrients such as P and N as well as reduced carbon and called the MBOD, the MBOD-P, and the MBOD-N, respectively. The results of bioassay by MBOD(Modified BOD) method showed that the MBOD, MBOD-P and MBOD-N value were found to be in the ranges of 3.8~96.0 mg$O_2$/l, 5.6~94.0 mg$O_2$/l and 42.0~220 mg$O_2$/l, respectively. And the the bioassay value was found to be the highest in Koryong area and the lowest in Waekwan area throughout the Nakdong river. The variations of MBOD-P and MBOD-N value showed similar tendencies to the variations of phosphorus and nitrogen value, respectively. By MBOD method, the relationships of MBOD, MBOD-P and MBOD-N value were MBOD ≒ MBOD-P 《 MBOD-N. The MBOD value was nearly equal to the MBOD-P value, and the MBOD-N value was 3 to 20 times more than the MBOD-P value, approximately. Therefore, in the Nakdong river, phosphorus was the limiting factor for algal growth during summer season. The algal growth potential as the concentration of chlorophyll-a in the summer was maximum 5 times more than standing crop as it.