• 제목/요약/키워드: Statistical terms

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Test of Normality Based on the Transformed Lorenz Curve

  • Kang, Suk-Bok;Cho, Young-Suk
    • Communications for Statistical Applications and Methods
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    • 제6권3호
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    • pp.901-908
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    • 1999
  • Using the Transformed Lorenz curve which is introduced by Cho et al.(1999) we propose the test statistic for testing of normality that is very important test in statistical analysis and compare the proposed test statistic with the Shapiro and Wilk's W test statistic in terms of the power of test through by Monte Carlo method.

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Modeling Extreme Values of Ground-Level Ozone Based on Threshold Methods for Markov Chains

  • Seokhoon Yun
    • Communications for Statistical Applications and Methods
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    • 제3권2호
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    • pp.249-273
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    • 1996
  • This paper reviews and develops several statistical models for extreme values, based on threshold methodology. Extreme values of a time series are modeled in terms of tails which are defined as truncated forms of original variables, and Markov property is imposed on the tails. Tails of the generalized extreme value distribution and a multivariate extreme value distributively, of the tails of the series. These models are then applied to real ozone data series collected in the Chicago area. A major concern is given to detecting any possible trend in the extreme values.

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A new statistical moment-based structural damage detection method

  • Zhang, J.;Xu, Y.L.;Xia, Y.;Li, J.
    • Structural Engineering and Mechanics
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    • 제30권4호
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    • pp.445-466
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    • 2008
  • This paper presents a novel structural damage detection method with a new damage index based on the statistical moments of dynamic responses of a structure under a random excitation. After a brief introduction to statistical moment theory, the principle of the new method is put forward in terms of a single-degree-of-freedom (SDOF) system. The sensitivity of statistical moment to structural damage is discussed for various types of structural responses and different orders of statistical moment. The formulae for statistical moment-based damage detection are derived. The effect of measurement noise on damage detection is ascertained. The new damage index and the proposed statistical moment-based damage detection method are then extended to multi-degree-of-freedom (MDOF) systems with resort to the leastsquares method. As numerical studies, the proposed method is applied to both single and multi-story shear buildings. Numerical results show that the fourth-order statistical moment of story drifts is a more sensitive indicator to structural stiffness reduction than the natural frequencies, the second order moment of story drift, and the fourth-order moments of velocity and acceleration responses of the shear building. The fourth-order statistical moment of story drifts can be used to accurately identify both location and severity of structural stiffness reduction of the shear building. Furthermore, a significant advantage of the proposed damage detection method lies in that it is insensitive to measurement noise.

Preservice Teachers' Difficulties with Statistical Writing

  • Park, Min-Sun;Park, Mimi;Lee, Eun-Jung;Lee, Kyeong Hwa
    • 한국수학교육학회지시리즈D:수학교육연구
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    • 제16권4호
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    • pp.265-276
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    • 2012
  • These days, with the emphasis on statistical literacy, the importance of communication is the focus of attention. Communication about statistics is important since it is a way of describing the understanding of concepts and the interpretation of data. However, students usually have trouble with expressing what they understand, especially through writing. In this paper, we examined preservice teachers' difficulties when they wrote about statistical concepts. By comparing preservice teachers' written responses and interview transcripts of the variance concept task, we could find the missing information in their written language compared to their verbal language. From the results, we found that preservice teachers had difficulty in connecting terms contextually and conceptually, presenting various factors of the concepts that they considered, and presenting the problem solving strategies that they used.

On Asymptotically Optimal Plug-in Bandwidth Selectors in Kernel Density Estimation

  • Song, Moon-Sup;Seog, Kyung-Ha;Sin sup Cho
    • Journal of the Korean Statistical Society
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    • 제20권1호
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    • pp.29-43
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    • 1991
  • Two data-based bandwidth selectors which are optimal in the sense that they achieve n$\^$-$\frac{1}{2}$/ rate of convergence in kernel density estimation are proposed. The proposed bandwidth selectors are constructed by modifying Park and Marron's plug-in method. The first modification is taking Taylor expansion of the mean integrated squared error to two more terms than in the case of plug-in method. The second is estimating more accurately the functionals of the unknown density appeared in the minimizer of the expansion by using higher order kernels. The proposed bandwidth selectors were proved to be optimal in terms of convergence rate. According to small-sample Monte Carlo studies, the proposed bandwidth selectors showed better performance than all the other bandwidth selectors considered in the simulation.

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Unbound Protein-Protein Docking Using Conformational Space Annealing

  • Lee, Kyoung-Rim;Joo, Kee-Hyoung;Lee, Joo-Young
    • 한국생물정보학회:학술대회논문집
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    • 한국생물정보시스템생물학회 2005년도 BIOINFO 2005
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    • pp.294-299
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    • 2005
  • We have studied unbound docking for 12 protein-protein complexes using conformational space annealing (CSA) combined along with statistical pair potentials. The CSA, a powerful global optimization tool, is used to search the conformational space represented by a translational vector and three Euler amgles between two proteins. The energy function consists of three statistical pair-wise energy terms; one from the distance-scaled finite ideal-gas reference state (DFIRE) approach by Zhou and the other two derived from residue-residue contacts. The residue-residue contact terms describe both attractive and repulsive interactions between two residues in contact. The performance of the CSA docking is compared with that of ZDOCK, a well-established protein-protein docking method. The results show that the application of CSA to the protein-protein docking is quite successful, indicating that the CSA combined with a good scoring function is a promising method for the study of protein-protein interaction.

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A NOTE ON CONSTRUCTING $2^{n}3^1$ AND $2^{1}3^3$ DESIGNS WHEN LINEAR TERMS ARE ESSENTIAL

  • LIAU PEN-HWANG
    • Journal of the Korean Statistical Society
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    • 제34권2호
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    • pp.141-151
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    • 2005
  • Under the assumption that the three-level factors are quantitative, the linear effects are taken more attention than the quadratic effects of the interaction terms. Webb (1971) presented some small incomplete factorial designs that are mixed two- and three-level designs with 20 or fewer runs. The designs provided the estimating linear-by-linear components of interactions between the three-level factors; moreover, they could also offer estimation of interactions that interest the experiments. Webb used ad hoc methods to find these plans; hence, there was still no unified structure to those experiments. In this paper, we develop the methods to construct the $2^{n}3^3$ and $2^{1}3^3$ designs. The designs constructed by these methods not only supply orthogonal estimates of all the main effects but also permit estimation of all the two-factor interactions not involving the quadratic effects. Furthermore, the designs we find are nearly orthogonal.

Design of the Variable Sampling Rates X-chart with Average Time to Signal Adjusted by the Sampling Cost

  • Park, Chang-Soon;Song, Moon-Sup
    • Journal of the Korean Statistical Society
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    • 제26권2호
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    • pp.181-198
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    • 1997
  • The variable sampling rates scheme is proposed by taking random sample size and sampling interval during the process. The performance of the scheme is measured in terms of the average time to signal adjusted by teh sampling cost when the process is out of control. This measurement evaluates the effectiveness of the scheme in terms of the cost incurred due to nonconformation as well as sampling. The variable sampling rates scheme is shown to be effective especially for small and moderate shifts of the mean when compared to the standard scheme.

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Variance components for two-way nested design data

  • Choi, Jaesung
    • Communications for Statistical Applications and Methods
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    • 제25권3호
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    • pp.275-282
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    • 2018
  • This paper discusses the use of projections for the sums of squares in the analyses of variance for two-way nested design data. The model for this data is assumed to only have random effects. Two different sizes of experimental units are required for a given experimental situation, since nesting is assumed to occur both in the treatment structure and in the design structure. So, variance components are coming from the sources of random effects of treatment factors and error terms in different sizes of experimental units. The model for this type of experimental situation is a random effects model with more than one error terms and therefore estimation of variance components are concerned. A projection method is used for the calculation of sums of squares due to random components. Squared distances of projections instead of using the usual reductions in sums of squares that show how to use projections to estimate the variance components associated with the random components in the assumed model. Expectations of quadratic forms are obtained by the Hartley's synthesis as a means of calculation.