• Tunnel and Underground Space
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• v.12 no.1
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• pp.19-30
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• 2002

Rock joint orientation is one of important geometric attributes that have an influence on the stability of rock structures such as rock slopes and tunnels. Especially, statistical models of the geometric attributes of rock joints can provide a probabilistic approach of rock engineering problems. The result from probabilistic modeling relies on the choice of statistical model. Therefore, it is critical to define a representative statistical model for joint orientation data as well as joint size and intensity and build up a series of modeling procedure including analytical validation. In this paper, we have examined a theoretical methodology for the statistical estimate and hypothesis analysis based upon Fisher distribution and bivariate normal distribution. In addition, we have proposed the algorithms of random number generator which is applied to the simulation of rock joint networks and risk analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2603-2609
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• 2014

Reliability analysis of mechanical systems requires statistical modeling of input random variables such as distribution function types and statistical parameters that affect the performance of the mechanical systems. Some random variables are correlated, but considered as independent variables or wrong assumptions on input random variables have been used. In this paper, joint distributions were modeled using copulas and Bayesian method from limited number of data. To verify the proposed method, statistical simulation tests were carried out for various number of samples and correlation coefficients. As a result, the Bayesian method selected the most probable copula types among candidate copulas even though the candidate copula shapes are similar for low correlations or the number of data is limited. The most probable copulas also yielded similar reliabilities with the true reliability obtained from a true copula, so that it can be concluded that the Bayesian method provides accurate statistical modeling for the reliability analysis.

• 한국임상약학회:학술대회논문집
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• 2007.12a
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• pp.196-197
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• 2007

• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.43-52
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• 1999

The local influence method is adapted to quadratic discriminant analysis for the identification of influential observations affecting the estimation of probability density function probabilities and log odds. The method allows a simultaneous perturbation on all observations so that it can identify multiple influential observations. The proposed method is applied to a real data set and satisfactory result is obtained.

• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.320-329
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• 1995

The purpose of this paper is to simplify and study the asymptotic distribution of the dimensionality estimators in discriminant analysis based on Akaike's and Mallows' methods for samples from a multivariate distribution with finite fourth moments.

• Journal of the Korean Statistical Society
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• v.5 no.1
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• pp.29-34
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• 1976

The techniques about the analysis of variance for quantitative variables have been well-developed. But when the variable is categorical, we must switch to a completely different set of varied techniques. R.J. Light and B.H. Margolin presented one kind of techniques for categorical data in their paper, where there are G unordered experimental groups and I unordered response categories.

• School Mathematics
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• v.19 no.4
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• pp.731-749
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• 2017

The purpose of this study is to find out whether the current mathematics textbooks are structured so as to cultivate students' statistical literacy. To do this, we analyzed the problems of the statistics units of 9 kinds of middle school 3rd grade mathematics textbook according to 2009 revised mathematics curriculum based on four types of context and statistical problem solving process. As a result of the analysis, among the four types of context, the problems that correspond to the type of personal context was the highest in 67% and among statistical problem solving process, the data analysis process was the highest in 72.85%. According to the results of this study, it is necessary to include the problems that can recognize the necessity of statistics through the use of various contexts and that can develop the statistical literacy through the activities that from the process of collecting data to guessing reasonable conclusions from the presented data.

• Women's Health Nursing
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• v.13 no.3
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• pp.211-218
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• 2007

Purpose: This study aimed to evaluate the accuracy and adequacy of research papers reporting statistical testings for mean differences. Methods: Original research articles utilized t-test, Chi-square test, and ANOVA were reviewed from Korean Journal of Women Health Nursing published from the year 2004 to 2006. Seventy-six papers were evaluated in accordance with formatted criteria in respect to an inclusiveness of research title, accuracy of statistical methods and presentation styles, and errors in reporting statistical outcomes. Results: Research titles were quite comprehensive, however overall accuracy of statistical values and basic formats reached only 60 to 80% by items. Details of the presentation in the reporting of outcomes were not complied with the guidelines, which need careful concerns of the writers. Errors of English in table presentation were found in more than 30% of the papers. Conclusion: The outcome would be reflected in the submission guidelines for future writers. To reach the level comparable with internationally recognized nursing journals, concrete knowledge to apply statistical methods should be ensured in the processes of submission, reviews, and editing.

• Communications for Statistical Applications and Methods
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• v.17 no.2
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• pp.205-222
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• 2010

A patent is a right of intellectual properties to an inventor or its assignee for a limited period under an international law. Not only in an invention of new machines, but it is competitive for using and creating technology in the world based on the patents. Most of the business models are good examples for patented technology, however a statistical analyzing model could be another one. In this paper we study and analyze the patents for the statistical analyzing and data mining models which are currently applied and registered, and suggest a statistical tool for analyzing and categorizing patent data. For this study all the patents in Korea and U.S. are listed and searched to sample the only cases concerning statistics.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.28.2-28.2
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• 2008

Recently, star sensors have been successfully used as main attitude sensors for attitude control in many satellites. This research presents the star visibility analysis for star trackers and the goal of this analysis is to make sure that the star tracker implementation is suitable to the mission profile and scenario and satisfies the requirement of attitude orbit control system. As a main optical attitude sensor imaging stars, accomodations of a star tracker should be optimized in order to improve the probability of the usage by avoiding the blinding (the unavailability) by the Sun and the Earth. For the analysis, a statistical approach and a time simulation approach are used. The statistical approach is based on the generation of numerous cases, to derive relevant statistics about Earth and Sun proximity probabilites for different lines of sight. The time simulation approach is performed for one orbit to check the statistical result and to refine the statistical result and accomodations of star trackers. In order to perform simulations first of all, an orbit and specific mission profiles of a satellite are set, next the earth proximity probability and the sun proximity probability are calculated by considering the attitude maneuvers and the geometry of the orbit, and then finally the unavailability positions are estimated. As a result, the optimized accomodations of two star trackers are suggested for the low earth orbit satellite.