• Communications for Statistical Applications and Methods
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• v.28 no.5
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• pp.477-491
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• 2021

The Markov modulated Brownian motion is a substantial generalization of the classical Brownian Motion. On the other hand, the Markovian arrival process (MAP) is a point process whose family is dense for any stochastic point process and is used to approximate complex stochastic counting processes. In this paper, we consider a superposition of the Markov modulated Brownian motion (MMBM) and the Markovian arrival process of jumps which are distributed as the bilateral ph-type distribution, the class of which is also dense in the space of distribution functions defined on the whole real line. In the model, we assume that the inter-arrival times of the MAP depend on the underlying Markov process of the MMBM. One of the subjects of this paper is introducing how to obtain the first passage probabilities of the superposed process using a stochastic doubling algorithm designed for getting the minimal solution of a nonsymmetric algebraic Riccatti equation. The other is to provide eigenvalue and eigenvector results on the superposed process to make it possible to apply the GTH-like algorithm, which improves the accuracy of the doubling algorithm.

• Journal of the Korean Data and Information Science Society
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• v.12 no.2
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• pp.125-143
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• 2001

We, in this paper, propose a kernel estimator of hazard ratio with censored survival data. The uniform consistency and asymptotic normality of the proposed estimator are proved by using counting process approach. In order to assess the performance of the proposed estimator, we compare the kernel estimator with Cox estimator and the generalized rank estimators of hazard ratio in terms of MSE by Monte Carlo simulation. Two examples are illustrated for our results.

• Asia Pacific Journal of Corpus Research
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• v.2 no.2
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• pp.31-41
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• 2021

This paper makes a quantitative analysis of the diachronic evolution of ancient Chinese vocabulary by constructing and counting a large-scale rough annotated corpus. The texts from Si Ku Quan Shu (a collection of Chinese ancient books) are automatically segmented to obtain ancient Chinese vocabulary with time information, which is used to the statistics on word frequency, standardized type/token ratio and proportion of monosyllabic words and dissyllabic words. Through data analysis, this study has the following four findings. Firstly, the high-frequency words in ancient Chinese are stable to a certain extent. Secondly, there is no obvious dissyllabic trend in ancient Chinese vocabulary. Moreover, the Northern and Southern Dynasties (420-589 AD) and Yuan Dynasty (1271-1368 AD) are probably the two periods with the most abundant vocabulary in ancient Chinese. Finally, the unique words with high frequency in each dynasty are mainly official titles with real power. These findings break away from qualitative methods used in traditional researches on Chinese language history and instead uses quantitative methods to draw macroscopic conclusions from large-scale corpus.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.8
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• pp.789-798
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• 2013

The procedures and relevant programs developed for analyzing mechanical load data of wind turbine generator systems, which are obtained through type certification tests, are verified. The following issues according to IEC 61400-13 are covered in the developed programs: data validation, time series analysis, summary load statistics, generation of fatigue load spectra, and estimation of equivalent loads. A capture matrix for normal power production is generated to determine whether the collected data sets are sufficient to carry out fatigue analysis. Fatigue load spectra are obtained through the rainflow counting method using 50 load ranges; finally, equivalent loads are calculated using different S-N curve slopes, m, according to the relevant materials. Case studies are performed using aero-elastic simulation data of the NREL 5 MW baseline wind turbine with a monopile foundation.

• Safety and Health at Work
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• v.8 no.3
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• pp.318-321
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• 2017

This commentary presents the regulatory backgrounds and development of the national proficiency testing (PT) scheme on asbestos analysis in the Republic of Korea. Since 2009, under the amended Occupational Safety and Health Act, the survey of asbestos in buildings and clearance test of asbestos removal works have been mandated to be carried out by the laboratories designated by the Ministry of Employment and Labor (MOEL) in the Republic of Korea. To assess the performance of asbestos laboratories, a PT scheme on asbestos analysis was launched by the Korea Occupational Safety and Health Agency (KOSHA) on behalf of the MOEL in 2007. Participating laboratories are evaluated once a year for fiber counting and bulk asbestos analysis by phase contrast microscopy and polarized light microscopy, respectively. Currently, the number of laboratory enrollments is > 200, and the percentage of passed laboratories is > 90. The current status and several significant changes in operation, sample preparations, and statistics of assigning the reference values of the KOSHA PT scheme on asbestos analysis are presented. Critical retrospect based on the experiences of operating the KOSHA PT scheme suggests considerations for developing a new national PT scheme for asbestos analysis.

• Journal of Periodontal and Implant Science
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• v.44 no.6
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• pp.288-292
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• 2014

Purpose: The purposes of this study were to assess the trend of use of statistical methods including parametric and nonparametric methods and to evaluate the use of complex statistical methodology in recent periodontal studies. Methods: This study analyzed 123 articles published in the Journal of Periodontal & Implant Science (JPIS) between 2010 and 2014. Frequencies and percentages were calculated according to the number of statistical methods used, the type of statistical method applied, and the type of statistical software used. Results: Most of the published articles considered (64.4%) used statistical methods. Since 2011, the percentage of JPIS articles using statistics has increased. On the basis of multiple counting, we found that the percentage of studies in JPIS using parametric methods was 61.1%. Further, complex statistical methods were applied in only 6 of the published studies (5.0%), and nonparametric statistical methods were applied in 77 of the published studies (38.9% of a total of 198 studies considered). Conclusions: We found an increasing trend towards the application of statistical methods and nonparametric methods in recent periodontal studies and thus, concluded that increased use of complex statistical methodology might be preferred by the researchers in the fields of study covered by JPIS.

• International Journal of Contents
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• v.5 no.2
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• pp.6-15
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• 2009

Recently many different programming languages have emerged for the development of bioinformatics applications. In addition to the traditional languages, languages from open source projects such as BioPerl, BioPython, and BioJava have become popular because they provide special tools for biological data processing and are easy to use. However, it is not well-studied which of these programming languages will be most suitable for a given bioinformatics task and which factors should be considered in choosing a language for a project. Like many other application projects, bioinformatics projects also require various types of tasks. Accordingly, it will be a challenge to characterize all the aspects of a project in order to choose a language. However, most projects require some common and primitive tasks such as file I/O, text processing, and basic computation for counting, translation, statistics, etc. This paper presents the benchmarking results of six popular languages, Perl, BioPerl, Python, BioPython, Java, and BioJava, for several common and simple bioinformatics tasks. The experimental results of each language are compared through quantitative evaluation metrics such as execution time, memory usage, and size of the source code. Other qualitative factors, including writeability, readability, portability, scalability, and maintainability, that affect the success of a project are also discussed. The results of this research can be useful for developers in choosing an appropriate language for the development of bioinformatics applications.

• Korean Journal of Child Studies
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• v.11 no.2
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• pp.5-23
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• 1990

The purpose of this study was to investigate the acquisition of number-word systems of young children. Specifically, the acquisition of Korean Number-Words(KNW) was compared with the acquisition of Chinese-derived Number-Words(CNW). The subjects included 120 children aged 2:5 to 5:11. The subjects oral counting using the two number word systems were audiotaped. Two coders transcribed the tapes. The data were analyzed by content analysis with descriptive statistics. The findings of this study showed that the acquisition of KNW began from around age two and the acquisition of CNW from around age three. From then, the acquisition of the two number-word systems was parallel. The acquisition of number-words began from the age of 2 years, increased slowly to the age of 4. and then increased rapidly after the age of 5. Although KNW were acquired earlier than CNW, at around the age of 5 years the acquisition of CNW surpassed the acquisition of KNW. The acquisition of number words consists of four developmental levels: Level I: beginning of acquisition of traditional KNW only Level II: beginning of acquisition of CNW with extension of KNW Level III: parallel extension of the two number-word systems Level IV: superior acquisition of CNW. The major error through all stages in the sequence of number words was the omission of one number-word. Younger children produced errors of omission of one, two or three number-words, whereas older children produced errors of nonstandard number-words and repetition.

• Journal of Information Management
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• v.42 no.3
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• pp.95-116
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• 2011

The purpose of this research is to examine the characteristics and problems of the OASIS, an web archive, developed and operated by the National Library of Korea. An analysis of 55 websites collected in seven subject areas, including 'Philosophy', 'Religion', 'Literature', 'Social Sciences-Politics', and 'Technology-Technology' in the OASIS website shows the following problems: lack of balance in subject distribution, lack of authority or scholarly value of some contents, unclear application of selection criteria for personal creators/publishers, ambiguous definition of 'archiving', and inappropriate counting of collection and usage statistics. Some comprehensive and systematic efforts to improve the OASIS contents seem to be urgently needed.

• Journal of the Korean School Mathematics Society
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• v.13 no.3
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• pp.381-395
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• 2010

The purpose of this paper is to examine the competence and the methods of problem solving in four operations word problems based on the informal knowledges by five-year-old children. The numbers which are contained in problems consist of the numbers bigger than 5 and smaller than 10. The subjects were 21 five-year-old children who didn't learn four operations. The interview with observation was used in this research. Researcher gave the various materials to children and permitted to use them for problem solving. And researcher read the word problems to children and children solved the problems. The results are as follows: five-year-old children have the competence of problem solving in four operations word problems. They used mental computation or counting all materials strategy in addition problem. The methods of problem solving were similar to that of addition in subtraction, multiplication and division, but the rate of success was different. Children performed poor1y in division word problems. According to this research, we know that kindergarten educators should be interested in children's informal knowledges of four operations including shapes, patterns, statistics and probability. For this, it is needed to developed the curriculum and programs for informal mathematical experiences.