• Title/Summary/Keyword: Homogeneity analysis

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Numerical Analysis of Acoustic Characteristics in Gas Turbine Combustor with Spatial Non-homogeneity

  • Sohn, Chae-Hoon;Cho, Han-Chang
    • Journal of Mechanical Science and Technology
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    • v.18 no.8
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    • pp.1461-1469
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    • 2004
  • Acoustic characteristics in an industrial gas-turbine combustor are numerically investigated by a linear acoustic analysis. Spatially non-homogeneous temperature field in the combustor is considered in the numerical calculation and the characteristics are analyzed in view of acoustic instability. Acoustic analyses are conducted in the combustors without and with acoustic resonator, which is one of the acoustic-damping devices or combustion stabilization devices. It has been reported that severe pressure fluctuation frequently occurs in the adopted combustor, and the measured signal of pressure oscillation is compared with the acoustic-pressure response from the numerical calculation. The numerical results are in good agreement with the measurement data. In this regard. the phenomenon of pressure fluctuation in the combustor could be caused by acoustic instability. From the numerical results for the combustor with present acoustic resonators installed, the acoustic effects of the resonators are analyzed in the viewpoints of both the frequency tuning and the damping capacity. It is found that the resonators with present specifications are not optimized and thus, the improved specification or design is required.

Efficient Classification of High Resolution Imagery for Urban Area

  • Lee, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.27 no.6
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    • pp.717-728
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    • 2011
  • An efficient method for the unsupervised classification of high resolution imagery is suggested in this paper. It employs pixel-linking and merging based on the adjacency graph. The proposed algorithm uses the neighbor lines of 8 directions to include information in spatial proximity. Two approaches are suggested to employ neighbor lines in the linking. One is to compute the dissimilarity measure for the pixel-linking using information from the best lines with the smallest non. The other is to select the best directions for the dissimilarity measure by comparing the non-homogeneity of each line in the same direction of two adjacent pixels. The resultant partition of pixel-linking is segmented and classified by the merging based on the regional and spectral adjacency graphs. This study performed extensive experiments using simulation data and a real high resolution data of IKONOS. The experimental results show that the new approach proposed in this study is quite effective to provide segments of high quality for object-based analysis and proper land-cover map for high resolution imagery of urban area.

Comparative Analysis of Flood Frequncy by Moment and L-moment in Weibull-3 distribution (Weibull-3 분포모형의 모멘트법 및 L-모멘트법에 의한 홍수빈도비교분석)

  • 이순혁;맹승진;송기헌;류경식;지호근
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1998.10a
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    • pp.331-337
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    • 1998
  • This study was carried out to derive optimal design floods by Weibull-3 distribution with the annual maximum series at seven watersheds along Man, Nagdong, Geum, Yeongsan and Seomjin river systems. Adequacy for the analysis of flood data used in this study was acknowledged by the tests of Independence, Homogeneity, detection of Outliers. Parameters were estimated by the Methods of Moments and L-Moments. Design floods obtained by Methods of Moments and L-Moments using different methods for plotting positions in Weibull-3 distribution were compared by the rotative mean error and relative absolute error. It has shown that design floods derived by the method of L-moments using Weibull plotting position formula in Weibull-3 distribution are much closer to those of the observed data in comparison with those obtained by method of moments using different formulas for plotting positions in view of relative mean and relative absolute error.

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Purification and Characterization of a Deoxyriboendonuclease from Mycobacterium smegmatis

  • Mandal, Prajna;Chakraborty, Phulghuri;Sau, Subrata;Mandal, Nitai Chandra
    • BMB Reports
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    • v.39 no.2
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    • pp.140-144
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    • 2006
  • A deoxyriboendonuclease has been purified to near homogeneity from a fast growing mycobacterium species, M. smegmatis and characterized to some extent. The size of enzyme is about 43 kDa as determined by a denaturing gel analysis. It shows optimum activity at $32^{\circ}C$ in Tris-HCl buffer (pH 7.2) containing 2.5 mM of $MgCl_2$. Both EDTA and $K^+$ but not $Na^+$ inhibit its activity. Evidences show that the enzyme is not a restriction endonuclease but catalyzes the endonucleolytic cleavage of both the double- as well as the single-strand DNA non-specifically. It has been shown that the cleavage by this enzyme generates DNA fragments carrying phosphate groups at 5' ends and hydroxyl group at the 3' ends, respectively. Analysis reveals that no endonuclease having size and property identical to our deoxyriboendonuclease had been purified from M. smegmatis before. The property of our enzymes closely matches with the deoxyriboendonucleases purified from diverse sources including bacteria.

Frequency Analysis of Extreme Rainfall by L-Moments (L-모멘트법에 의한 극치강우의 빈도분석)

  • Maeng, Sung-Jin;Lee, Soon-Hyuk;Kim, Byung-Jun
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.225-228
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    • 2002
  • This research seeks to derive the design rainfalls through the L-moment with the test of homogeneity, independence and outlier of data on annual maximum daily rainfall in 38 Korean rainfall stations. To select the fit appropriate distribution of annual maximum daily rainfall data according to rainfall stations, applied were Generalized Extreme Value (GEV), Generalized Logistic (GLO) and Generalized Pareto (GPA) probability distributions were applied. and their aptness was judged Dusing an L-moment ratio diagram and the Kolmogorov-Smirnov (K-S) test, the aptitude was judged of applied distributions such as GEV, GLO and GPA. The GEV and GLO distributions were selected as the appropriate distributions. Their parameters were estimated Targetingfrom the observed and simulated annual maximum daily rainfalls and using Monte Carlo techniques, the parameters of GEV and GLO selected as suitable distributions were estimated and. dDesign rainfallss were then derived, using the L-moment. Appropriate design rainfalls were suggested by doing a comparative analysis of design rainfall from the GEV and GLO distributions according to rainfall stations.

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Estimates of Genotoxic Effect by the Pollen Analysis of Vines and Fruit trees

  • Sirunik, Yervandyan;Anna, Nebish;Rouben, Arutyunyan
    • Korean Journal of Environmental Biology
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    • v.24 no.4
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    • pp.368-371
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    • 2006
  • The complex analysis of male reproductive system of vines and fruit-tyees growing in zone of the Armenian Nuclear Power Plant (ANPP) is realized. The obtained data demonstrate that the homogeneous pollen with high fertility and optimal morphometric parameters in all variants is formed. The obtained results demonstrate that there is no one-sided effect of ANPP on the development and formation of investigated male generative system of vines and fruit trees. Thus, on the base of obtained results we can't confirm its deleterious effect on the environment.

Flood Frequency Analysis using L, L1 and L2-Moment Methods (L, L1 및 L2-모멘트법에 의한 홍수빈도분석)

  • Lee, Soon-Hyuk;Maeng, Sung-Jin;Ryoo, Kyong-Sik;Jee, Ho-Keun
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2001.10a
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    • pp.310-313
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    • 2001
  • This study was conducted to derive optimal design floods by Gumbel, GEV, GLO and GPA distributions for the annual maximum series at sixteen watersheds. Adequacy for the analysis of flood data used in This study was established by the tests of Independence, Homogeneity, detection of Outliers. Parameters were estimated by the Methods of L, L1 and L2-moments. Design floods obtained by Methods of L, L1 and L2-moments using Gringorten methods for plotting positions in GEV distribution were compared by the Relative Mean Errors and Relative Absolute Errors.

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Production and Characterization of Monoclonal Antibodies to Yeast Mitochondrial RNA Polymerase Specificity Factor

  • Lee, Chang-Hwan;Jang, Sei-Heon
    • BMB Reports
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    • v.31 no.6
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    • pp.607-610
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    • 1998
  • Transcription of mitochondrial DNA in the yeast S. cerevisiae depends on recognition of a consensus nonanucleotide promoter sequence by mitochondrial RNA polymerase specificity factor, which is a 43 kDa polypeptide encoded by the nuclear MTF1 gene. Mtf1p has only limited amino acid sequence homology to bacterial sigma factors, but functions in many ways like sigma in that it is required for promoter recognition and initiation of transcription. To analyze the corebinding region of Mtf1p, monoclonal antibodies to this protein were prepared. Recombinant Mtf1p overproduced in E. coli was purified to near homogeneity and used to raise monoclonal antibodies (mAbs). From fused cells screened for Mtf1p mAbs by immunodot blot analysis, 19 positive clones were initially isolated. Further analysis of positive clones by Western blotting resulted in 4 mAbs of Mtf1p.

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FEM Analysis of Void Closure Behavior during Open Die Forging of Rectangular Billets (사각 빌렛 자유단조시 내부기공폐쇄거동 유한요소해석)

  • 천명식;류종수;문영훈
    • Transactions of Materials Processing
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    • v.13 no.2
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    • pp.148-153
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    • 2004
  • Finite element analysis of open die forging process to make rectangular billet has been performed in this study. Three dimensional rigid-plastic finite element method was used to analyze the effects of process variables, forging pass design and die configurations on the void closure phenomena to maximize the internal deformation for better structural homogeneity and center-line consolidation of the rectangular billet. The effect of anvil width ratio, anvil pitch, anvil shape and number of pass has been estimated by the degree of void closure ratio. Although it is difficult to optimize process parameters in the operational environments, favourable process conditions are suggested for better product quality.

Hypothesis Testing: Means and Proportions (평균과 비율 비교)

  • Pak, Son-Il;Lee, Young-Won
    • Journal of Veterinary Clinics
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    • v.26 no.5
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    • pp.401-407
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    • 2009
  • In the previous article in this series we introduced the basic concepts for statistical analysis. The present review introduces hypothesis testing for continuous and categorical data for readers of the veterinary science literature. For the analysis of continuous data, we explained t-test to compare a single mean with a hypothesized value and the difference between two means from two independent samples or between two means arising from paired samples. When the data are categorical variables, the $x^2$ test for association and homogeneity, Fisher's exact test and Yates' continuity correction for small samples, and test for trend, in which at least one of the variables is ordinal is described, together with the worked examples. McNemar test for correlated proportions is also discussed. The topics covered may provide a basic understanding of different approaches for analyzing clinical data.