• Title/Summary/Keyword: comparison method

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Analysis of Measurement Error for PM-2.5 Mass Concentration by Inter-Comparison Study (비교 실험을 통한 PM-2.5 질량농도의 측정오차 분석)

  • Jung, Chang-Hoon;Park, Jin-Hee;Hwang, S.M.
    • Journal of Environmental Impact Assessment
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    • v.19 no.4
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    • pp.431-441
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    • 2010
  • In this study, inter-comparison for PM-2.5 was undertaken. The PM-2.5 mass concentrations using the gravimetric and beta-attenuation methods were compared during the winter in 2007. Two different types of conventional filter-based measurements (Cyclone type and Impactor type) were also collocated and the measurement data was compared with each other. As a result, continuous PM-2.5 data using beta attenuation method show a comparable mass concentration with gravimetric measurement when the inlet of beta-gauge sampler is heated. The results also showed that the cyclone type shows a little high PM-2.5 concentration than Impactor type. In all the sampling cases, the correlations between measurement methods are high. Subsequently, this study suggests that highly correlated relationship between PM-2.5 measurement instruments can be obtained through the inter-comparison results based on filterb-ased gravimetric method and more intensive measurement and theoretical studies are needed in order to clarify the measurement errors for different sampler types.

Evaluation and Comparison of the Solubility Models for Solute in Monosolvents

  • Min-jie Zhi;Wan-feng Chen;Yang-bo Xi
    • Korean Chemical Engineering Research
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    • v.62 no.1
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    • pp.53-69
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    • 2024
  • The solubility of Cloxacillin sodium in ethanol, 1-propanol, isopropanol, and acetone solutions was measured at different temperatures. The melting property was also tested by using a differential scanning calorimeter (DSC). Then, the solubility data were fitted using Apelblat equation and λh equation, respectively. The Wilson model and NRTL model were not utilized to correlate the test data, since Cloxacillin sodium will decompose directly after melting. For comparison purposes, the four empirical models, i.e., Apelblat equation, λh equation, Wilson model and NRTL Model, were evaluated by using 1155 solubility curves of 103 solutes tested under different monosolvents and temperatures. The comparison results indicate that the Apelblat equation is superior to the others. Furthermore, a new method (named the calculation method) for determining the Apelblat equation using only three data points was proposed to solve the problem that there may not be enough solute in the determination of solubility. The log-logistic distribution function was used to further capture the trend of the correlation and to make better quantitative comparison between predicted data and the experimental ones for the Apelblat equation determined by different methods (fitting method or calculation method). It is found that the proposed calculation method not only greatly reduces the number of test data points, but also has satisfactory prediction accuracy.

A Comparison Study on Total Least Squares and Least Squares (토털최소제곱법과 최소제곱법의 비교연구)

  • 이임평;최윤수;권재현
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2003.10a
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    • pp.15-19
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    • 2003
  • The Total Least Squares (TLS) method is introduced in comparison with the conventional Least Squares (LS) method. The principles and mathematical models for both methods are summarized and the comparison results from their applications to a simple geometric example, fitting a straight line to a set of 2D points are presented. As conceptually reasoned, the results clearly indicate that LS is more susceptible of producing wrong parameters with worse precision rather than TLS. For many applications in surveying, can adjustment computation and parameter estimation based on TLS provide better results.

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Bayesian Multiple Comparison of Binomial Populations based on Fractional Bayes Factor

  • Kim, Dal-Ho;Kang, Sang-Gil;Lee, Woo-Dong
    • Journal of the Korean Data and Information Science Society
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    • v.17 no.1
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    • pp.233-244
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    • 2006
  • In this paper, we develop the Bayesian multiple comparisons procedure for the binomial distribution. We suggest the Bayesian procedure based on fractional Bayes factor when noninformative priors are applied for the parameters. An example is illustrated for the proposed method. For this example, the suggested method is straightforward for specifying distributionally and to implement computationally, with output readily adapted for required comparison. Also, some simulation was performed.

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PRECONDITIONED SSOR METHODS FOR THE LINEAR COMPLEMENTARITY PROBLEM WITH M-MATRIX

  • Zhang, Dan
    • Communications of the Korean Mathematical Society
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    • v.34 no.2
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    • pp.657-670
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    • 2019
  • In this paper, we consider the preconditioned iterative methods for solving linear complementarity problem associated with an M-matrix. Based on the generalized Gunawardena's preconditioner, two preconditioned SSOR methods for solving the linear complementarity problem are proposed. The convergence of the proposed methods are analyzed, and the comparison results are derived. The comparison results showed that preconditioned SSOR methods accelerate the convergent rate of the original SSOR method. Numerical examples are used to illustrate the theoretical results.

NUMERICAL STUDY ON DROPLET SPREAD MOTION AFTER IMPINGEMENT ON THE WALL USING IMPROVED CIP METHOD (수정된 CIP방법을 이용한 벽면 충돌 후 액적의 퍼짐 현상에 대한 수치해석 연구)

  • Son, S.Y.;Ko, G.H.;Lee, S.H.;Ryou, H.S.
    • Journal of computational fluids engineering
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    • v.15 no.4
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    • pp.25-31
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    • 2010
  • Interface tracking of two phase is significant to analyze multi-phase phenomena. The VOF(Volume of Fluid) and level set are well known interface tracking method. However, they have limitations to solve compressible flow and incompressible flow at the same time. CIP(Cubic Interpolate Propagation) method is appropriate for considering compressible and incompressible flow at once by solving the governing equation which is divided up into advection and non-advection term. In this article, we analyze the droplet impingement according to various We number using improved CIP method which treats nonlinear term once more comparison with original CIP method. Furthermore, we compare spread radius after droplet impingement on the wall with the experimental data and original CIP method. The result using improved CIP method shows the better result of the experiments, comparison with result of original CIP method, and it reduces the mass conservation error which is generated in the numerical analysis comparison with original CIP method.

Effect Analysis on Red Light Camera for Signalized Intersection Safety -Focused on Side Right-Angle Collision Accidents- (신호교차로 안전성향상을 위한 단속카메라의 효과분석 연구 -측면직각 충돌사고를 중심으로-)

  • Oh, Ju Taek;Kim, Yong Seok;Lee, Yong Chul
    • International Journal of Highway Engineering
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    • v.17 no.1
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    • pp.119-127
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    • 2015
  • PURPOSES : Before-and-after studies of red light cameras were conducted with the aim of reducing the number of side right-angle collisions. Three different methods were used for the before-and-after studies, and the analysis results were compared. METHODS : This research used the naive before-and-after method, the comparison-group method, and the empirical Bayes method to study the effects of red light cameras on side-angle collisions. The results of the three before-and-after methods were compared and interpreted in terms of safety indications at signalized intersections. RESULTS : The research results showed that side right-angle collisions can be reduced by installing red light cameras at signalized intersections. All three methods guarantee safety improvements of 25~30% on average. With regard to the results of each method, the naive before-and-after method, the comparison-group method, and the empirical Bayes method showed safety improvements of 25.6%, 27.8%, and 29.7%, respectively. CONCLUSIONS : It was concluded that red light cameras are an effective countermeasure to improve intersection safety. In particular, by installing red light cameras, side right-angle collisions can be reduced by up to approximately 25~30%.

Nonparametric multiple comparison method using aligned method and joint placement in randomized block design with replications (반복이 있는 랜덤화 블록 모형에서 정렬방법과 결합위치를 이용한 비모수 다중비교법)

  • Hwang, Juwon;Kim, Dongjae
    • The Korean Journal of Applied Statistics
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    • v.31 no.5
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    • pp.599-610
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    • 2018
  • The method of Mack and Skillings (Technometrics, 23, 171-177, 1981) is a nonparametric multiple comparison method in a randomized block design with replications. This method is likely to result in loss of information because each block is ranked using the average of observations instead of repeated observations. In this paper, we proposed a new nonparametric multiple comparison method in the randomized block model with replications using an alignment method proposed by Hodges and Lehmann (The Annals of Mathematical Statistics, 33, 482-497, 1962) that extend the joint placement method proposed by Chung and Kim (Communications for Statistical Applications and Methods, 14, 551-560, 2007). In addition, Monte Carlo simulation compared the family wise error rate and power with the parametric method and the nonparametric method.

On Multiple Comparison of Geometric Means of Exponential Parameters via Graphical Model (그래프 모형을 이용한 지수분포 모수들의 기하평균 비교에 관한 연구)

  • Kim, Dae-Hwang;Kim, Hea-Jung
    • The Korean Journal of Applied Statistics
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    • v.19 no.3
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    • pp.447-460
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    • 2006
  • This paper develops a multiple comparison method for finding an optimal ordering of K geometric means of exponential parameters. This is based on the paired comparison experimental arrangement whose results can naturally be represented by a completely oriented graph. Introducing posterior preference probabilities and stochastic transitivity conditions to the graph, we obtain a new graphical model that yields criteria for the optimal ordering in the multiple comparison. Necessary theories involved in the method and some computational aspects are provided. Some numerical examples are given to illustrate the efficiency of the suggested method.

Comparison of isoBOC derivatives, TBDMS derivatives, with US EPA Method in the sensitivity of Alkylphenols, Chlorophenols, and Bisphenol A potential field-screening applications of GC/MS-SIM

  • Kim, Hyub;Hong, Jong-Ki;Kim, Yong-Hwa;Kim, Kyoung-Rae
    • Proceedings of the PSK Conference
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    • 2002.10a
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    • pp.235.2-236
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    • 2002
  • The alkylphenols, chlorophenols and bisphenol A were determined by gas chromatography/mass spectrometry-selected ion monitoring mode followed by three work-up methods for comparison: EPA method, isoBOC derivatization method and TBDMS derivatization method. Eleven phenols in water samples were extracted with dichloromethane. (omitted)

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