• The Korean Journal of Applied Statistics
• /
• v.11 no.2
• /
• pp.257-268
• /
• 1998

Many epidemiological studies investigate whether an association exists between a binary risk factor X and a binary response variable Y. They analyse whether an observed association between X and Y persists when the level of another factor Z that might influence the association is controlled. This involves testing conditional independence of X and Y controlling for Z. The Mantel-Haenszel test is most widely used to test conditional independence for sparse tables. But if the association between X and Y varies along the levels of Z, Mantel-Haenszel test has a low power problem. In this study, we propose an alternative test procedure which overcomes the low power problem in that case. We find out the null distribution of the alternative test statistic and compare its performance with the Mantel-Haenszel test by simulation.

• The Korean Journal of Applied Statistics
• /
• v.34 no.4
• /
• pp.523-536
• /
• 2021

Although there exist numerous measures of association, most of them are lacking in generality in that they do not intend to measure the association between heterogeneous type of random variables. On the other hand, many statistical analyzes dealing with complex data sets require a very sophisticate measure of association. In this note, the p-value of independence tests is utilized to obtain a measure of association. The proposed measure of association have some consistency in measuring association between various types of random variables.

• Proceedings of the Korea Contents Association Conference
• /
• 2014.11a
• /
• pp.241-242
• /
• 2014

이 연구에서는 경찰의 조직적 특성 중 경찰관서의 규모에 따른 직무만족과 이직의도 수준을 비교 분석하고자 하였다. 경찰관서 규모에 따른 직무만족과 이직의도 수준의 차이를 살펴보기 위해 독립변수는 관서규모와 급지, 종속변수는 직무만족과 이직의도로 구성하여 일원변량 분산분석(One-way ANOVA)을 실시하였다. 그 결과 관서규모와 급지 둘 다 직무만족과 이직의도에서 통계적으로 유의한 수준의 차이가 발견되었다.

• Proceedings of the Korea Contents Association Conference
• /
• 2013.05a
• /
• pp.187-188
• /
• 2013

이 연구에서는 경찰의 조직적 특성 중 경찰관서의 규모에 따른 스트레스 수준을 비교 분석하고자 하였다. 경찰관서 규모에 따른 스트레스 수준의 차이를 살펴보기 위해 독립변수는 관서규모와 급지, 종속변수는 생활 스트레스, 직무 스트레스, 외상성 스트레스로 구성하여 일원변량 분산분석(One-way ANOVA)을 실시하였다. 그 결과 관서규모와 급지 둘 다 직무 스트레스와 외상성 스트레스에서 통계적으로 유의한 수준의 차이가 발견되었다.

• Communications for Statistical Applications and Methods
• /
• v.5 no.2
• /
• pp.447-458
• /
• 1998

본 논문에서는 환자의 수명과 치료횟수의 모형화를 위해 관측가능한 공변량을 포함하는 동시에 두 변수에 영향을 미치는 관측불가능한 환경요인을 고려하기 위한 개별환경효과모형을 도입하고자 한다. 개별환경효과를 나타내는 분포를 감마분포로 가정하여 사망시간과 치료횟수의 모형을 개발하고, 모형에 포함된 모수의 추론과정을 논의하며, 개발된 모형을 Autologous Blood and Marrow Transplant Registry(ABMTR)에 등록된 환자의 자료에 적용하여 환경효과를 고려하지 않은 독립모형과 비교하고자 한다.

• Journal for History of Mathematics
• /
• v.1 no.1
• /
• pp.1-8
• /
• 1984

본 논문에서는 수학적인 사유형식을 시기적으로 수평과 수직의 축에서 관찰할 목적으로 Descartes의 원정리을 생각한다. 이 정리에 잔해서는 지금까지 접척원의 곡률의 연구가 있으며, 특히 내접원, 외접원의 곡률을 중심적으로 수많은 방법으로 다루어지고 있다. 분 논문에서 이들 방법을 일반화하여 고찰하며 특히 독립적으로 연구되어온 화산의 방법과 비교한다.

• Journal of Korea Water Resources Association
• /
• v.45 no.2
• /
• pp.191-201
• /
• 2012

This study reviewed the parameter estimation procedure of the Freund bivariate exponential distribution for the decision of the annual maximum rainfall event. The method of moments was reviewed first, whose results were compared with those from the method of maximum likelihood. Both methods were applied to the hourly rainfall data of the Seoul rain gauge station measured from 1961 to 2010 to select the annual maximum rainfall events, which were also compared each other. The results derived are as follows. First, when applying the method of moments for the parameter estimation, it was found necessary to consider the correlation coefficient between the two variables as well as the mean and variance. Second, the method of maximum likelihood was better to reproduce the mean, but the method of moments was better to reproduce the annual variation of the variance. Third, The annual maximum rainfall events derived were very similar in both cases. Among differently selected annual maximum rainfall events, those with the higher rainfall amount were selected by the method of maximum likelihood, but those with the higher rainfall intensity by the method of moments.

• Journal of Korean Society of Forest Science
• /
• v.98 no.3
• /
• pp.351-356
• /
• 2009

This study purposed to judge potential possibility of building highly precise empirical model using environmental variables. Environmental variables such as altitude, mean annual rainfall, mean annual temperature and organic matter ratio of soil were added to height and diameter model for Chamaecyparis obtusa, and examined accuracy and residuals of prediction model. Improvement in precision was found for the Gompertz polymorphic height model by including mean temperature and altitude as independent variables, while the Gompertz diameter model with annual rainfall and altitude was showed improvement of precision and accuracy. Comparing the improvement of precision between the model before adding environmental variables and the model after adding them, an improvement or some ratio was obtained though it is not obvious. Therefore, there is enough proof that adding environmental variables, which can be easily acquired relatively when considering the difficulties of measurement and budget, into the model as independent variables would improve the accuracy and precision of growth models.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.5 no.6
• /
• pp.568-574
• /
• 2010

In an effort to improve the speech recognition rate, we investigated performance comparison between speaker-independent and gender-specific speech recognitions. For this purpose, 20 male and 20 female speakers each pronounced 300 isolated Korean words and the speeches were divided into 4 groups: female, male, and two mixed genders. To examine the validity for the gender-specific speech recognition, Fourier spectrum and MFCC feature vectors averaged over male and female speakers separately were examined. The result showed distinction between the two genders, which supports the motivation for the gender-specific speech recognition. In experiments of speech recognition rate, the error rate for the gender-specific case was shown to be less than50% compared to that of the speaker-independent case. From the obtained results, it might be suggested that hierarchical recognition of gender and speech recognition might yield better performance over the current method of speech recognition.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.14 no.2
• /
• pp.415-420
• /
• 2010

This paper describes the design overview of shared file system $SANique^{TM}$ and analyzes the performance evaluation results of I/O intensive stress test based on various cluster file system architectures. Especially, we illustrate the performance analysis for the comparison results between the $SANique^{TM}$ and the Linux file system EXT3 system that is used to generally in Unix world. In order to perform our evaluation, Oracle 10g database system is operated on the top of cluster file system, and we developed the various kinds of testing tools which are compiled by ESQL/C from Oracle. Three types of architectures are used in this performance evaluation. Those are the cluster file system $SANique^{TM}$, EXT3 and the combined architecture of $SANique^{TM}$ and EXT3. In this paper, we present that the results of $SANique^{TM}$ outperforms other cluster file systems in the overhead for providing the true sharing over the connecting server nodes.