• The korean journal of orthodontics
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• v.34 no.5 s.106
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• pp.371-379
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• 2004

The purpose of this study was to investigate the changes and types of statistical methods used in the Korean Journal of Orthodontics (KJO) and the American Journal of Orthodontics and Dentofacial Orthopedics (AJODO) from )999 to 2003. The frequency of use, transitions, assumption check of statistical methods and types of advanced statistical methods were examined from each journal. The study consisted of 247 articles published in the KJO and randomly chosen 50 articles per year which were original articles and used statistical methods T-test, analysis of variance(ANOVA), correlation analysis, nonparametric analysis. regression analysis chi-square test. factor analysis, were the order of statistical methods most frequently used in the KJO, while t-test. ANOVA, nonparametric analysis, correlation analysis, regression analysis, chi-square test. factor analysis. were the order of statistical methods used in the AJODO The changes of statistical methods observed in the KJO were not significant $(X^2=17.4\;p=0.5881)$ but the changes observed in the AJODO was seen to be significant $(x^2=42.4,\;p=0.0397)$ Some of the studies examined had overlooked the assumptions of the statistical methods employed. Data investigation such as outlier should be performed before analysis and alternative statistical approaches are applied for a small sample size. Types of advanced statistical methods were factor analysis and discriminant analysis in the KJO and Intention-To-Treat (ITT) analysis in clinical trials through multi-center, survival analysis and Generalized Estimating Equations (GEE) in the AJODO. Appropriate analysis approaches and interpretations should be applied for the correlated and repeated measurements of the orthodontic data set.

• Communications for Statistical Applications and Methods
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• v.7 no.3
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• pp.871-884
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• 2000

Using simulation, we compare the perturbation analysis estimate and the forward difference estimate for the first and second derivatives of performance measures in a Markov renewal process. We find the perturbation analysis estimate has much les mean squared error than the traditional forward difference estimate.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.1
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• pp.55-69
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• 2016

The purpose of this study is to investigate statistical units of elementary school mathematics textbooks upon on the statistical problem solving process to provide useful information for qualitative improvement of developing curriculum and teaching materials. This study analyzed the statistical units from the textbooks of 1st to 6th year along the 2009 revised national curriculum. The analysis frame is based on the 4 phases of the statistical problem solving process: formulate questions, plan and collect data, present and analyze data and interpret data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.35-40
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• 2006

For the maritime traffic safety assessment of vessels navigating in harbor or fairway, simulation techniques by using shiphandling simulator system have been traditionally used. When designing the simulation experiments and when analyzing the simulation results, however, there has been a little systematic method. Ship-handling simulations can be regarded as a kind of statistical experiment by using ship-handling simulator system, which means that shiphandling simulation conditions should be designed statistically and that the simulation results should be statistically analyzed as well. For the safe and economic design of harbor and fairway, reasonable decisions based upon the scientific analysis of shiphandling simulation results are indispensable. In this paper, various statistical methods, such as Bayes theorem, statistical hypothesis testing, and probability distributions, are reviewed with a view to application to maritime traffic safety assessment. It is expected that more reasonable decisions on harbor and fairway design can be made from shiphandlers' view point by using statistical methods.

• Journal of Families and Better Life
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• v.26 no.2
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• pp.83-101
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• 2008

This research performs a multi comparison between the age of old households and the economic structure according to accommodation type as well as analyzing the economical structural difference of each type based on the features of aged households. The paper classified aged households into 3 groups according to age distribution. The economic structure analysis according to the age of old households and accommodation type was shown as follow: First, the economical structural analysis based on the age of old households showed a statistical difference in the total, labor, business, property and transfer income variables according to the age of each sample group. However, the non-business income and liabilities did not show a significant difference. Second, in the analysis of different economic earnings and initial expenses of middle-aged households according to the age distribution group showed a disparity in the total, labor, business, property, and transfer income variables according to the age of each sample group. However, aged households showed a statistical difference in total, labor, business and transfer income variables. Third, in the analysis of difference in the expense provision and size of consumption, there was a statistical difference in the expense variables of total consumption, food, dining out, electricity, water, furniture, kitchen supplies, clothing, shoe, education, culture, entertainment, transportation, and communication. Fourth, in the analysis of difference in the size of consumption expense, the initial and middle-aged households showed a statistical difference in the total consumption, food, dining out, electricity, water, furniture, kitchen supplies, clothing, shoe, education, culture, entertainment, transportation, communication, and consumption expense variables. However, the analysis of aged households has shown a statistical difference in the total consumption, food, dining out, electricity, water, furniture, kitchen supplies, clothing, shoe, education, culture, entertainment, transportation, and communication expense variables. The study found a statistical difference in the expense for hygienics that did not appear in the initial and middle-aged households.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.12
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• pp.31-36
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• 2007

This paper presents a novel statistical characterization for accurate timing analysis in Partially-Depleted Silicon-On-Insulator (PD-SOI) circuits in BSIMSOI3.2 100nm technology. The proposed timing estimate algorithm is implemented in Matlab, Hspice, and C, and it is applied to ISCAS85 benchmarks. The results show that the error is within 5% compared with Monte Carlo simulation results.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.332-338
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• 2018

To perform the Maritime Safety Audi Scheme, $10^{-4}$ was constantly applied without adjustment when evaluating the proximity of the fairway. The necessity of applying the different aberrancy probabilities from the different proximity of the fairway depending on the shape of the route and the size of the ship was validated using marine simulations. Marine simulation was performed to evaluate the validity of statistical analysis-based aberrancy probability according to the different shapes of routes and ship size presented in the previous study. As results, the validity of the criterion of the statistical analysis-based aberrancy probability was confirmed by comparing with the results of simulation-based aberrancy probabilities. The results support that the aberrancy probabilities by the types of a vessel could be different based on the type and size of vessels. The results motivate that further investigation is required to find the reasonable criteria of the aberrancy probabilities for the maritime traffic safety audit according to the fairway shape and the size of the vessel.

• Journal of the Korean Statistical Society
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• v.25 no.1
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• pp.49-66
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• 1996

The singular value decomposition is one of the most useful methods in the area of matrix computation. It gives dimension reduction which is the centeral idea in many multivariate analyses. But this method is not resistant, i.e., it is very sensitive to small changes in the input data. In this article, we derive the resistant version of singular value decomposition for principal component analysis. And we give its statistical applications to biplot which is similar to principal component analysis in aspects of the dimension reduction of an n x p data matrix. Therefore, we derive the resistant principal component analysis and biplot based on the resistant singular value decomposition. They provide graphical multivariate data analyses relatively little influenced by outlying observations.

• IE interfaces
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• v.16 no.3
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• pp.344-351
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• 2003

Critical dimension is one of the most important characteristics of up-to-date integrated circuit devices. Hence, critical dimension control in a semiconductor wafer fabrication process is inevitable in order to achieve optimum device yield as well as electrically specified functions. Currently, in complex semiconductor wafer fabrication processes, statistical methodologies such as Shewhart-type control charts become crucial tools for practitioners. Meanwhile, given a critical dimension sampling plan, the analysis of variance technique can be more effective to investigating critical dimension variation, especially for on-chip and on-wafer variation. In this paper, relating to a typical sampling plan, linear statistical models are presented for the analysis of critical dimension variation. A case study is illustrated regarding a semiconductor wafer fabrication process.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.335-337
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• 2009

A scanning electron microscope(SEM) is a system that visualizes complex surface features. The resolution of SEM is affected by each of equipment components. In this study, we examined the effects of the four factors including the beam current, magnification, voltage and working distance. A statistical analysis was conducted to investigate the main and interaction effects. For a systematic characterization, a $2^4$ full factorial experiment was conducted. The $R^2$ of constructed statistical model was 88.9%. The main effect revealed that the current and working distance are dominant factors. Of the interactions, those between the current and voltage yielded the highest interaction. 3D plots generated from the model were used to explore various parameter effects.