• Title/Summary/Keyword: 근사적 분산

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Real-Time Video Quality Assessment of Video Communication Systems (비디오 통신 시스템의 실시간 비디오 품질 측정 방법)

  • Kim, Byoung-Yong;Lee, Seon-Oh;Jung, Kwang-Su;Sim, Dong-Gyu;Lee, Soo-Youn
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.46 no.3
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    • pp.75-88
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    • 2009
  • This paper presents a video quality assessment method based on quality degradation factors of real-time multimedia streaming services. The video quality degradation is caused by video source compression and network states. In this paper, we propose a blocky metric on an image domain to measure quality degradation by video compression. In this paper, the proposed boundary strength index for the blocky metric is defined by ratio of the variation of two pixel values adjacent to $8{\times}8$ block boundary and the average variation at several pixels adjacent to the two boundary pixels. On the other hand, unnatural image movement caused by network performance deterioration such as jitter and delay factors can be observed. In this paper, a temporal-Jerkiness measurement method is proposed by computing statistics of luminance differences between consecutive frames and play-time intervals between frames. The proposed final Perceptual Video Quality Metric (PVQM) is proposed by consolidating both blocking strength and temporal-jerkiness. To evaluate performance of the proposed algorithm, the accuracy of the proposed algorithm is compared with Difference of Mean Opinion Score (DMOS) based on human visual system.

Analysis of Steady and Unsteady Flow Around a Ship Using a Higher-Order Boundary Element Method (고차경계요소법에 의한 선체주위 유동해석)

  • Sa-Y. Hong;Hang-S. Choi
    • Journal of the Society of Naval Architects of Korea
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    • v.32 no.1
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    • pp.42-57
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    • 1995
  • An efficient and accurate scheme has been constructed by taking advantages of the hi-quadratic spline scheme and the higher-order boundary element method selectively depending on computation domains. Boundary surfaces are represented by 8-node boundary elements to describe curved surfaces of a ship and its neighboring free surface more accurately. The variation of the velocity potential complies with the characteristics of the 8-node element on the body surface. But on the free surface, it is assumed to follow that of the hi-quadratic spline scheme. By which, the free surface solution is free from numerical damping and has better numerical dispersion property. As numerical examples, steady and unsteady Neumann-Kelvin problems are considered. Numerical results for a submerged spheroid, Series 60($C_B=0.6$) and a modified support the proposed method. Finally, a new upstream radiation condition is derived using a wave equation operator in order to deal with problems for subcritical reduced frequency. The relevance of this operator has been confirmed in the case of unsteady Kelvin source potential.

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Evaluation of an Enzyme-Linked Imrnunosorbent Assay for the Detection of Aflatoxin $B_1$ from the Imported Cereals (수입곡물 중의 Alfatoxin $B_1$ 검출을 위한 효소면역측정법의 평가)

  • 손동화;박애란;이인원
    • Microbiology and Biotechnology Letters
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    • v.20 no.3
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    • pp.355-361
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    • 1992
  • In order to evaluate an enzyme-linked immunosorbent assay(ELISA) for practical use in detecting aflatoxin $B_1(AFB_1)$ from cereals, we compared $AFB_1$ concentrations of samples contaminated artificially or naturally that were quantitated by the ELISA with those spiked or quantitated by HPLC. Cotton seed meals(19 items), rape seed meals(ll), soybean meals(9), and corns(3) imported from foreign countries were used as sample cereals. The standard curves of each cereal class showed that 1-100 ng/g of $AFB_1$ from cereals could be assayed by the ELISA. When artificially contaminated cereals were assayed by ELISA, the average recovery of AFB! from samples spiked to 3 ng/g and more was 138%(68-193%), although that spiked to 1 ng/g was somewhat high(268%). The average C.V. of recovery was 7.0%(0-22.2%). When naturally contaminated cereals were assayed, the concentrations of $AFB_1$ below 10 ng/g especially from rape seed meals quantitated by ELISA were much lower than those determined by HPLC. However, the concentrations of 10 ng/g and more from samples, except a few extraordinary samples. quantitated by ELISA were similar to those determined by HPLC, especially in case of cotton seed meals whose average recovery (ELISA/HPLC) was 153%. In conclusion, the ELISA was elucidated such as a practical tool to detect $AFB_1$ of 10 ng/g and more from cereals.

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A Goodness of Fit and Validity Study of the Korean Radiological Technologists' Core Job Com petency Model (방사선사 핵심 직무역량 모델의 적합성 및 타당성 검증)

  • Lim, Chang-Seon;Cho, A Ra;Hur, Yera;Choi, Seong-Youl
    • Journal of radiological science and technology
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    • v.40 no.3
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    • pp.469-484
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    • 2017
  • Radiological Technologists deals with the life of a person which means professional competency is essential for the job. Nevertheless, there have been no studies in Korea that identified the job competence of radiologists. In order to define the core job competencies of Korean radiologists and to present the factor models, 147 questionnaires on job competency of radiology were analyzed using 'PASW Statistics Version 18.0' and 'AMOS Version 18.0'. The valid model consisted of five core job competencies ('Patient management', 'Health and safety', 'Operation of equipment', 'Procedures and management') and 17 sub - competencies. As a result of the factor analysis, the RMSEA value was 0.1 and the CFI, and TLI values were close to 0.9 in the measurement model of the five core job competencies. The validity analysis showed that the mean variance extraction was 0.5 or more and the conceptual reliability value was 0.7 or more, And there was a high correlation between subordinate competencies included in each subordinate competencies. The results of this study are expected to provide specific information necessary for the training and management of human resources centered on competence by clearly showing the job competence required for radiologists in Korea's health environment.

Application Examples of Daecheong Dam for Efficient Water Management Based on Integrated Water Management (통합물관리 기반 효율적 물관리를 위한 대청댐 실무적용 사례)

  • Kang, Kwon-Su;Heo, Jun-Haeng
    • Proceedings of the Korea Water Resources Association Conference
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    • 2017.05a
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    • pp.85-85
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    • 2017
  • 효율적 물관리란 거대한 물순환 과정에서 인간이 편안한 삶을 사는데 필요한 물의 이용효율을 극대화하는 것이다. 과거의 물관리는 이원화된 수량과 수질관리, 수량중심에서는 용수공급과 홍수조절이 주요한 관심사였다. 현재는 과거의 물관리에 친수와 환경을 더한 복잡한 분야로 확대되고 있다. 통합물관리란 물을 최적으로 관리하기 위해 물관리 이해당사자간의 소통과 물 기술의 고도화를 기반으로 기존에 분산된 물관리 구성요소들(시설 정보, 수량 수질 등)을 권역적으로 관리하는 것을 말한다. 본 연구에서는 대청댐 방류에 따른 금강 하류부의 홍수추적을 위해 수행한 댐하류 소유역별 강우량 빈도분석 과정, 용담댐 방류를 고려한 대청댐 홍수도달시간 검토, Poincare Section과 신경망기법을 이용한 수문자료 예측, 추계학적 다변량 해석과 다변량 신경망해석에 의한 대청댐 유입량 산정과정, 보조여수로 건설에 따른 주여수로와 보조여수로간의 연계운영방안, 단계(관심, 주의, 경계, 심각)를 고려한 대청댐 확보수위 산정, 저수지 중장기 운영계획 수립과 댐 운영 기준수위를 결정하기 위해 누가차분방식으로 적용되는 갈수기 유입량 빈도분석에 대한 실무적용 사례를 소개하고자 한다. 강우량 빈도분석 과정은 L-모멘트방법(Hosking과 Wallis, 1993)을 적용하였고, 홍수도달시간 검토는 평균유속, 하류 수위상승 기점 영향검토, 수리학적 모형(FLDWAV, Progressive lag method 등)을 활용하였다. 카오스 이론을 도입하여 대청댐 수문자료의 상관성 검토 및 추계학적 모형을 이용한 모의발생을 유도하여 수문자료 예측을 시행하였다. 추계학적 모형과 신경망모형 연구의 대상은 대청댐으로, 시계열 자료는 댐의 월강우량, 월유입량, 최고기온, 평균기온, 최소기온, 습도, 증발량 등의 자료를 기반으로 하였다. 적용기간은 1981~2009년의 자료를 이용하여 2010년 1월부터 12월까지 12개월 동안의 월유입량을 예측하였다. 수문자료 해석의 기본이 되는 약 30년간의 자료를 이용하여 분석을 실시하였다. 대청댐의 유입량 예측을 위해 적용된 모형으로는 추계학적 모형인 ARMA모형, TF모형, TFN 모형 등이 적용되었고, 또한 신경망 모형의 종류인 다층 퍼셉트론, PCA모형 등을 활용하여 실측치와 가장 가깝게 근사화시키는 방법론을 찾고자 하였다. 또한, 기존여수로와 보조여수로 연계운영을 위해 3차원 수치해석을 통한 댐하류 안정성 검토 및 확보수위 산정을 통해 단계(관심, 주의, 경계, 심각)별로 대처가 가능한 수위를 산정하였다.

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Evaluation of Methods Used in the Calculation of Condition Index Using the Mussel, Mytilus coruscus (Gould, 1861) Collected from Chuja Island, Cheju, Korea (추자도산 홍합, Mytilus coruscus (Gould, 1861) 의 Condition Index 산정에 대한 연구)

  • 강도형;최광식
    • The Korean Journal of Malacology
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    • v.15 no.1
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    • pp.57-62
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    • 1999
  • Condition indices (Cl) are considered to be useful measurements of the nutritive and health status of bivalves although studies on Cl of bivalves are limited due to the lack of a standard formula for calculating Cl. This study attempts to generate Cl of the mussel, Mytilus coruscus inhabiting along the coastal area of Chuja Island in Cheju using three primary formulas. the formulas used in this study: (1) Cl-vol= [tissue dry weight (g) 1000] /shell cavity volume (ml). (2) Cl-wt= [tissue dry weight (g) 1000] / internal shell cavity capacity (g). (3) Cl-size= tissue wet weight (g)/[shell length (mm)]$\^$3/. Monthly condition indices calculated with the three formulas are compared using ANOVA, Duncan's multiple range test and Pearson correlation coefficient. In Chuja Island M. coruscus collected ranged from 50 to 180 mm in shell length. Monthly ranges of Cl-values were 67.48 to 140.61 (Cl-vol), 74.67 to 118.02 (Cl-wt) and 1.4 10$\^$-5) to 1.6 10$\^$-5/ (Cl-size). Cl-vol values in August were higher than two Cl-values in the other months. Monthly Cl-vol was significantly different from Cl-wt and Cl-size. (p<0.05). The results of this study suggest that volumetric condition index (Cl-vol) used in this study is acceptable as a standard measure to evaluate conditions of M. coruscus.

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IR Study on the Adsorption of Carbon Monoxide on Silica Supported Ruthenium-Nickel Alloy (실리카 지지 루테늄-니켈 합금에 있어서 일산화탄소의 흡착에 관한 IR 연구)

  • Park, Sang-Youn;Yoon, Dong-Wook
    • Applied Chemistry for Engineering
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    • v.17 no.4
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    • pp.349-356
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    • 2006
  • We have investigated adsorption and desorption properties of CO adsorption on silica supported Ru/Ni alloys at various Ru/Ni mole content ratio as well as CO partial pressures using Fourier transform infrared spectrometer (FT-IR). For Ru-$SiO_{2}$ sample, four bands were observed at $2080.0cm^{-1}$, $2021.0{\sim}2030.7cm^{-1}$, $1778.9{\sim}1799.3cm^{-1}$, $1623.8cm^{-1}$ on adsorption and three bands were observed at $2138.7cm^{-1}$, $2069.3cm^{-1}$, $1988.3{\sim}2030.7cm^{-1}$ on vacumn desorption. For Ni-$SiO_{2}$ sample, four bands were observed at $2057.7cm^{-1}$, $2019.1{\sim}2040.3cm^{-1}$, $1862.9{\sim}1868.7cm^{-1}$, $1625.7cm^{-1}$ on adsorption and two bands were observed at $2009.5{\sim}2040.3cm^{-1}$, $1828.4{\sim}1868.7cm^{-1}$ on vacumn desorption. These absorption bands correspond with those of the previous reports approximately. For Ru/Ni(9/1, 8/2, 7/3, 6/4, 5/5; mole content ratio)-$SiO_{2}$ samples, three bands were observed at $2001.8{\sim}2057.7cm^{-1}$, $1812.8{\sim}1926.5cm^{-1}$, $1623.8{\sim}1625.7cm^{-1}$ on adsorption and three bands were observed at $2140.6cm^{-1}$, $2073.1cm^{-1}$, $1969.0{\sim}2057.7cm^{-1}$ on vacumn desorption. The spectrum pattern observed for Ru/Ni-$SiO_{2}$ sample at 9/1 Ru/Ni mole content ratio on CO adsorption and on vacumn desorption is almost like the spectrum pattern observed for Ru-$SiO_{2}$ sample. But the spectrum patterns observed for Ru/Ni-$SiO_{2}$ samples under 8/2 Ru/Ni mole content ratio on CO adsorption and vacumn desorption are almost like the pattern observed for $Ni-SiO_{2}$ sample. It may be suggested surfaces of alloy clusters on the Ru/Ni-$SiO_{2}$ samples contain more Ni components than the mole content ratio of the sample considering the above phenomena. With Ru/Ni-$SiO_{2}$ samples the absorption band shifts may be ascribed to variations of surface concentration, strain variation due to atomic size difference, variation of bonding energy and electronic densities, and changes of surface geometries according to surface concentration variation. Studies for CO adsorption on Ru/Ni alloy cluster surface by LEED and Auger spectroscopy, interation between Ru/Ni alloy cluster and $SiO_{2}$, and MO calculation for the system would be needed to look into the phenomena.

Runoff and soil loss on newly reclaimed upland (야산개발지(野山開發地)의 토양침식(土壤侵蝕)에 관(關)하여)

  • Jung, Yeong Sang;Shin, Jae Sung;Shin, Yong Hwa
    • Korean Journal of Soil Science and Fertilizer
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    • v.9 no.1
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    • pp.9-16
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    • 1976
  • In order to investigate inherent erodibility of the soil, which is a major factor is soil erosion prediction, a survey on runoff and soil loss of reclaimed upland soil was carried out by using a portable rainulator. The relations of soil loss and some physical properties of the soil were discussed. The soil erodibility factor for Universal soil loss equation was calculated and compared with that of Wischmeier's nomograph. The result were as follows: 1. Total runoff increased for finer textured soil in order of Jeonnam silty clay loam, Songjeong clay loam, Yesan loam, Samgag and Sangju sandy loam. Total soil loss and soil content in runoff were not correspondently related with textural characteristic in order of Jeonnam, Samgag, Sangju, Yesan, and Songjeong. Total runoff, soil loss, and soil content in runoff were increased for steeper slope. 2. Soil loss and soil content in runoff negatively correlated with organic matter content of surface soil, while positively correlated with dispersion ratio, clay ratio, silt content, and significantly correlated with Middleton erosion ratio for coarser textured soil but not correctly related for finer textured soil. 3. The soil erodibilty factor K values for Universal soil loss equation were 0.32 for Jeonnam, 0.22 for Samgag, 0.17 for Sangju, 0.15 for Yesan, and 0.13 for Songjeong respectively. These values were close to those from Wischmeier's nomograph. So, it seems that the nomograph is useful for estimation of soil loss in Korea.

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