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        검색결과 71

        61.
        2016.11 KCI 등재 서비스 종료(열람 제한)
        A new prediction scheme has been proposed for the robust teleoperation in a non-visible environment. The positioning error caused by the time delay in the non-visible environment has been compensated for by the Smith predictor and the sensory data have been estimated by the Grey model. The Smith predictor is effective for the compensation of the positioning error caused by the time delay with a precise system model. Therefore the dynamic model of a mobile robot has been used in this research. To minimize the unstable and erroneous states caused by the time delay, the estimated sensor data have been sent to the operator. Through simulations, the possibility of compensating the errors caused by the time delay has been verified using the Smith predictor. Also the estimation reliability of the measurement data has been demonstrated. Robust teleoperations in a non-visible environment have been performed with a mobile robot to avoid the obstacles effective to go to the target position by the proposed prediction scheme which combines the Smith predictor and the Grey model. Even though the human operator is involved in the teleoperation loop, the compensation effects have been clearly demonstrated.
        62.
        2016.03 KCI 등재 서비스 종료(열람 제한)
        In this paper, we propose a new method for improving the accuracy of localizing a robot to find the position of a robot in indoor environment. The proposed method uses visible light for indoor localization with a reference receiver to estimate optical power of individual LED in order to reduce localization errors which are caused by aging of LED components and different optical power for each individual LED, etc. We evaluate the performance of the proposed method by comparing it with the performance of traditional model. In several simulations, probability density functions and cumulative distribution functions of localization errors are also obtained. Results indicate that the proposed method is able to reduce localization errors from 7.3 cm to 1.6 cm with a precision of 95%.
        63.
        2014.12 KCI 등재 서비스 종료(열람 제한)
        대규모 실내 3D 게임 장면에서 차폐 컬링 정보를 미리 계산하는 잠재적 가시 집합(potentially visible set: PVS)은 데이터를 처리하고 저장해야하는 양이 상당히 크지만 많은 부분이 0으로 표현된다. 본 논문에서는 모바일 환경의 3D 게임 장면 트리 구성 중에 PVS 데이터를 ZRLE (zero run length encoding) 방식으로 압축하는 효과적인 하드웨어 압축 구조를 설계한다. 3D 게임 시뮬레이션을 통하여 제안하는 구조의 PVS 데이터 압축 비율, PVS 컬링과 절두체 컬링에 따른 렌더링 속도 (frame per second: FPS)를 분석하였다.
        64.
        2013.10 KCI 등재 서비스 종료(열람 제한)
        Graphene oxide (GO)-titania composites have emerged as an attractive heterogeneous photocatalyst that can enhance the photocatalytic activity of TiO2 nanoparticles owing to their potential interaction of electronic and adsorption natures. Accordingly, TiO2-GO mixtures were synthesized in this study using a simple chemical mixing process, and their heterogeneous photocatalytic activities were investigated to determine the degradation of airborne organic pollutants (benzene, ethyl benzene, and o-xylene (BEX)) under different operational conditions. The Fourier transform infrared spectroscopy results demonstrated the presence of GO for the TiO2-GO composites. The average efficiencies of the TiO2-GO mixtures for the decomposition of each component of BEX determined during the 3-h photocatalytic processes were 26%, 92%, and 96%, respectively, whereas the average efficiencies of the unmodified TiO2 powder were 3%, 8%, and 10%, respectively. Furthermore, the degradation efficiency of the unmodified TiO2 powder for all target compounds decreased during the 3-h photocatalytic processes, suggesting a potential deactivation even during such a short time period. Two operational conditions (air flow entering into the air-cleaning devices and the indoor pollution levels) were found to be important factors for the photocatalytic decomposition of BEX molecules. Taken together, these results show that a TiO2-GO mixture can be applied effectively for the purification of airborne organic pollutants when the operating conditions are optimized.
        65.
        2012.12 KCI 등재 서비스 종료(열람 제한)
        Brown rice grain pigments of black rice have a higher content of bioactive substances such as anti-mutagenic substance than the non-pigmented rice grain. The major anthocyanin pigment contained in black rice was cyanidin-3-glucoside. This study was conducted to establish a rapid analysis method for determining cyanidin-3-glucoside contents in flour and whole rice seeds of black rice using VIS/NIRS technique. A total of 60 black rice samples were used for VIS/NIRS equation model development and validation. The value of coefficient of determination of external validation (r 2 ) and standard error of performance (SEP) in whole rice seed sample were 0.653 and 97.2, respectively. Therefore, the value of it seemed to be difficult to analyze cyanidin-3-glucoside content in whole rice seed samples using VIS/NIRS. However, in rice flour sample, the best accurate equation model was obtained from the partial least square regression (PLS) method. The value of r 2 , SEP and bias were 22.5, 0.922 and -1.45 in the calibration transformed to the N-point smooth of log 1/R signal, 5 factors, respectively. Therefore, the results of our study clearly demonstrate that the VIS/NIRS method would be applicable only for rapid determination of cyanidin-3-glucose content in black rice flour samples.
        66.
        2012.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The objective of this study was to develop models for the predict of the milk properties (fat, protein, SNF, lactose, MUN) of unhomogenized milk using the visible and near-infrared (NIR) spectroscopic technique. A total of 180 milk samples were collected from dairy farms. To determine optimal measurement temperature, the temperatures of the milk samples were kept at three levels (5℃, 20℃, and 40℃). A spectrophotometer was used to measure the reflectance spectra of the milk samples. Multilinear-regression (MLR) models with stepwise method were developed for the selection of the optimal wavelength. The preprocessing methods were used to minimize the spectroscopic noise, and the partial-least-square (PLS) models were developed to prediction of the milk properties of the unhomogenized milk. The PLS results showed that there was a good correlation between the predicted and measured milk properties of the samples at 40℃ and at 400∼2,500 nm. The optimal-wavelength range of fat and protein were 1,600∼1,800 nm, and normalization improved the prediction performance. The SNF and lactose were optimized at 1,600∼1,900 nm, and the MUN at 600∼800 nm. The best preprocessing method for SNF, lactose, and MUN turned out to be smoothing, MSC, and second derivative. The Correlation coefficients between the predicted and measured fat, protein, SNF, lactose, and MUN were 0.98, 0.90, 0.82, 0.75, and 0.61, respectively. The study results indicate that the models can be used to assess milk quality.
        67.
        2008.11 KCI 등재 서비스 종료(열람 제한)
        Enhancing with non-metallic elemental nitrogen(N) is one of several methods that have been proposed to modify the electronic properties of bulk titanium dioxide(TiO2), in order to make TiO2 effective under visible-light irradiation. Accordingly, current study evaluated the feasibility of applying visible-light-induced TiO2 enhanced with N element to cleanse aromatic compounds, focusing on xylene isomers at indoor air quality(IAQ) levels. The N-enhanced TiO2 was prepared by applying two popular processes, and they were coated by applying two well-known methods. For three o-, m-, and p-xylene, the two coating methods exhibited different photocatalytic oxidation(PCO) efficiencies. Similarly, the two N-doping processes showed different PCO efficiencies. For all three stream flow rates(SFRs), the degradation efficiencies were similar between o-xylene and m,p-xylene. The degradation efficiencies of all target compounds increased as the SFR decreased. The degradation efficiencies determined via a PCO system with N-enhanced visible-light induced TiO2 was somewhat lower than that with ultraviolet(UV)-light induced unmodified TiO2, which was reported by previous studies. Nevertheless, it is noteworthy that PCO efficiencies increased up to 94% for o-xylene and 97% for the m,p-xylene under lower SFR(0.5 L min-1). Consequently, it is suggested that with appropriate SFR conditions, the visible-light-assisted photocatalytic systems could also become important tools for improving IAQ.
        68.
        2005.12 KCI 등재 서비스 종료(열람 제한)
        벼 영양진단에서 중요한 성분인 생체잎의 질소함량을 NIRS를 이용하여 신속하고 정확하게 분석하기 위해 최적의 검량식 작성에 관한 일련의 시험을 실시한 결과는 다음과 같다. 벼 생체엽 질소함량 검량식의 결정계수는 익산, 정읍, 부안지역이 각각 0.879, 0.858, 0.819였다. Outlier를 제거한 후 검량식을 다시 작성한 결과 0.896, 0.878, 0.88~% 로 각각 0.017, 0.02, 0.061씩 향상되었다. Merge 기능을 이용하여 검량식을 합병한 후 검량식을 다시 작성한 결과 0.971로 정확도가 더욱 향상되었다. 벼 생체엽의 질소함량 검량식에 의한 분석값과 습식분석 평균값의 차이는 0.001~% 를 나타냈다. 이와 같은 결과로서 건조와 분쇄과정을 생략하기 때문에 시료의 변질을 막을 수 있고 시간과 비용을 줄일 수 있는 벼 생잎의 질소농도 측정이 근적외분석기술에 의해 가능할 것으로 판단되었다.
        70.
        1991.09 KCI 등재 서비스 종료(열람 제한)
        In order to grow InGaAsP epitaxial layer on GaAs by LPE, an accurate phase diagram for In-Ga-As-P quarternary compounds is required. But the short wavelength InGaAsP/GaAs phase diagram for full wavelength range was not yet reported. In this study, therefore, a theoretical calculation has been carried out by using thermodynamic's equation for InGaAsP/GaAs in order to get the relation between the mole fraction of the sloute and solid phase compounds. And the calculation being compared with the dta of Kawanishi et. al, the result has been shown that his phase diagram obtained by the calculation can apply to growing InGaAsP/GaAs by LPE.
        71.
        1986.12 KCI 등재 서비스 종료(열람 제한)
        벼의 엽색은 시비시기를 결정하는데 주요한 인자로써 가시부 영역에서 해석하고, 이들 엽색을 지배하는 광합성색소는 T.L.C.로 분리하여 검토하였다. 1. 벼의 엽색은 413, 432, 453nm(청색부)와 662nm(적색부)에서 흡광되였고, 그 중에서 최대흡광은 432, 662 nm 이었다. 2. 양흡광도비(청색부/적색부)는 벼 생태형간에는 근 차이는 없었으나. 비료간에는 비료양이 증가할수록 적었다. 3. 양흡광도비와 엽색도 및 엽록소함량과는 부의 유의상관이 인정되었다. 4. 광합성색소 조성비율은 출수기에서는 녹색계통색소, 출수후 30일에는 황색계통색소의 조성비율이 각각 컸다. 5. 벼 생태형별 광합성색소율 Chl. a의 조성비율은 출수기에는 다수계품종이 일반계품종보다 컸고, 출수후 30일에는 일반계품종이 다수계품종보다 컸으나, carotene는 그 반대이었다.
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