• Journal of the Korean Data and Information Science Society
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• v.26 no.1
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• pp.261-269
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• 2015

Nowadays the application of change point analysis has been indispensable in a wide range of areas such as quality control, finance, environmetrics, medicine, geographics, and engineering. Identification of times where process changes would help minimize the consequences that might happen afterwards. The main objective of this paper is to compare the change-point detection capabilities of Bayesian estimate and maximum likelihood estimate. We applied Bayesian and maximum likelihood techniques to formulate change points having a step change and multiple number of change points in a Poisson rate. After a signal from c-chart and Poisson cumulative sum control charts have been detected, Monte Carlo simulation has been applied to investigate the performance of Bayesian and maximum likelihood estimation. Change point detection capacities of Bayesian and maximum likelihood estimation techniques have been investigated through simulation. It has been found that the Bayesian estimates outperforms standard control charts well specially when there exists a small to medium size of step change. Moreover, it performs convincingly well in comparison with the maximum like-lihood estimator and remains good choice specially in confidence interval statistical inference.

• Imaging Science in Dentistry
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• v.41 no.1
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• pp.7-10
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• 2011

Purpose : The purpose of this study was to compare the conventional and digital radiography in the estimation of working length in mandibular molars. Materials and Methods : Sixty molar teeth were selected and divided into three groups in the basis of canal curves (0-$15^{\circ}$, 15-$30^{\circ}$, > $30^{\circ}$). After the placement of a 15 K-file, radiographs were taken with a conventional film (Fspeed) and a digital sensor. Canal lengths were measured in these images by two observers. Statistical analysis was performed with repeated measures of ANOVA and paired sample t-test with 95% confidence. Results : There was a high inter-observer agreement on the measurements of working length in conventional and digital radiographs. There was no significant difference between the mean values of measurements in conventional and digital radiography. Moreover, there was no significant difference between conventional and digital radiography with the actual values in the basis of canal curves. Conclusion : The accuracy of conventional and digital radiography in the determination of the working length was in an acceptable range.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.92-98
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• 2003

ISO 9000 is an efficient quality system for the customer's confidence and satisfaction. Of late years, the revised edition of ISO 9000 duality management system may give lots of positive business values to companies running ISO 9000 system Despite its tremendous popularity, there is some critisism against the effect and performance or ISO 9000 certification. This research explores the performances and effects of ISO 9000 quality system in small & medium size industrial companies. For this research, 202 companies certified by ISO 9000 standard and 67 companies not certified as contrast group were selected. The related data were collected by web-Poll survey. The major analyses are focused on the effect and performance or the ISO 9000 certification. and we established various hypotheses to verify the effect and performance or quality system. Results or statistical analyses show that total performance or qualify system is significantly different between certified companies and not certified.

• ALGAE
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• v.22 no.2
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• pp.57-67
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• 2007

We analyzed the nuclear-encoded large subunit ribosomal RNA gene (LSU rDNA) sequences of 19 dinoflagellates occurring in costal waters off Korea and reconstructed a phylogenetic tree containing 74 representative species from 37 distinct genera. Of these, the LSU rDNA sequences of Amylax triacantha (Jörgensen) Sournia, Gonyaulax verior Sournia (= Amylax diacantha Meunier), Gyrodinium fissum (Levander) Kofoid et Swezy, Katodinium glaucum (Lebour) Lebour III, Noctiluca scintillans (Macartney) Kofoid et Swezy, Oxyphysis oxytoxoides Kofoid, and Pyrophacus steinii (Schiller) Wall et Dale are reported for the first time. Our LSU rDNA tree consistently placed Oxyrrhis marina Dujardin and N. scintillans at the most primitive positions, giving rise to a strongly supported monophyletic group of typical dinoflagellate species belonging to the Dinophyceae. The phylogenetic relationships among the typical dinoflagellates, however, were not resolved in the higher taxonomic levels in general. Only genera at terminal branches were usually supported with high confidence. The Dinophysiales, represented by Dinophysis species and O. oxytoxoides, formed a strongly supported monophyletic assemblage. The Gymnodiniales and Peridiniales were recovered as polyphyletic groupings. Members of the Gonyaulacales were consistently grouped together, but lacked statistical support. Within this order, the Ceratiaceae and Goniodomataceae each formed a monophyletic group, but the Gonyaulacaceae was polyphyletic. The phylogenetic relationships of the Gonyaulacaceae were generally congruent with differences in the combinations of the apical pore complex, hypothecal organization and thecal formula.

• Journal of Preventive Medicine and Public Health
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• v.48 no.5
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• pp.225-230
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• 2015

Objectives: The epidemiological characteristics of breast cancer incidence by age group in Korean women are unique. This systematic review aimed to investigate the association between hormone replacement therapy (HRT) and breast cancer risk in Korean women. Methods: We searched electronic databases such as KoreaMed, KMbase, KISS, and RISS4U as well as PubMed for publications on Korean breast cancer patients. We also conducted manual searching based on references and citations in potential papers. All of the analytically epidemiologic studies that obtained individual data on HRT exposure and breast cancer occurrence in Korean women were selected. We restricted the inclusion of case-control studies to those that included age-matched controls. Estimates of summary odds ratio (SOR) with 95% confidence intervals (CIs) were calculated using random effect models. Results: One cohort and five case-control studies were finally selected. Based on the heterogeneity that existed among the six studies (I-squared=70.2%), a random effect model was applied. The summary effect size of HRT history from the six articles indicated no statistical significance in breast cancer risk (SOR, 0.983; 95% CI, 0.620 to 1.556). Conclusions: These facts support no significant effect of HRT history in the risk of breast cancer in Korean women. It is necessary to conduct a pooled analysis.

• The Korean Journal of Applied Statistics
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• v.17 no.3
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• pp.489-498
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• 2004

In this paper, a new form of linear models referred to as generalized weighted linear models is proposed. The proposed models assume that the relationship between the response variable and explanatory variables can be modelled by a distribution function of the response mean and a weighted linear combination of distribution functions of covariates. This form addresses a structural problem of the link function in the generalized linear models in which the parameter space may not be consistent with the space derived from linear predictors. The maximum likelihood estimation with Lagrange's undetermined multipliers is used to estimate the parameters and resampling method is applied to compute confidence intervals and to test hypotheses.

• Journal of Soil and Groundwater Environment
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• v.23 no.1
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• pp.41-53
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• 2018

Comprehensive statistical analysis for the 127 groundwater monitoring stations in Jeju Island during 2005~2015 was carried out for the re-establishment of management groundwater level. Three probability distribution functions such as normal distibution, GEV (General Extreme Value) distribution, and Gumbel distribution were applied and the maximum likelihood method was used for parameter estimation of each distribution. AIC (Akaike information criterion) was calculated based on the estimated parameters to determine the proper probability distribution for all 127 stations. The results showed that normal distribution and Gumble distribution were found in 11 stations. Whereas GEV distribution were found in 105 stations, which covered most of groundwater monitoring stations. Therefore, confidence levels should be established in accord with the proper probability distribution when groundwater level management is determined.

• Korean Journal of Childcare and Education
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• v.16 no.2
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• pp.141-160
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• 2020

Objective: The purpose of this study was to investigate structural relationships among variables related to pre-service childcare teachers' teaching efficacy. Methods: The participants in this study were 408 students in the department of child studies. The students completed questionnaires assessing pre-service childcare teachers' teaching efficacy, social support, self-esteem, and satisfaction level for childcare practicum. Statistical methods for the data analysis were the SPSS 19.0 and AMOS 20.0. And the Maximum likelihood estimation method was used to model fit. Goodness of fit was evaluated using the SRMR, RMSEA and its 90% confidence interval, CFI, and TLI. Results: First, pre-service childcare teachers' social support, self-esteem and satisfaction level for childcare practicum were found to affect their teaching efficacy directly. Also pre-service childcare teachers' social support was found to affect their self-esteem and satisfaction level for childcare practicum directly. Conclusion/Implications: This study is theoretically meaningful in that it shows that high social support, self-esteem, and satisfaction level for childcare practicum can be the main factors that can increase the effectiveness of pre-service childcare teachers' teaching efficacy.

• Journal of Korean Academy of Rural Health Nursing
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• v.2 no.1
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• pp.33-42
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• 2007

Purpose: This study was done to determine the extent of Clonorchis sinensis infections as well as other parasitic infections and to determine the growth rate. Method: Analyzed test results were from 1,050 bowel samples taken at 3 public health subcenters located in Muju, North Jeolla Province during February and March 2007. Result: The results are summarized as follows; The egg positive rate by stool examination was 4.3%. Ascaris lumbricoides, Enterobius vermicularis, Clonorchis sinensis, Trichuris trichiura, Metagonimus, Paragonimus were detected. No one was infected with multiple parasites. Infection rate for Clonorchis sinensis was 3.5%. Statistical correlation to Clonorchis sinensis infection rate was as follows; Gender (p=0.001), Age (p=0.005), Proximity to a river (p<0.000), Drinking (p<0.000), Smoking (p=0.009), Cooking of freshwater fish (p<0.000), Confidence in subjective health status (p=0.032), Family history of infection (p=0.005), No significant correlation was found between Clonorchis sinensis infection rate and duration of stay (p=0.809) in the agricultural communities or between Clonorchis sinensis infection and knowledge of Clonorchis sinensis (p=0.113). Conclusion: The results of this survey show that there is a need to develop a program to test the condition of Clonorchis Sinensis infection and its growth rate in residents of rural communities.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3483-3488
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• 2012

Objective: Several studies have demonstrated associations between the TERT rs2736098 single nucleotide polymorphisms (SNPs) and susceptibility to cancer development. However, there are conflicting results. A systematic meta-analysis was therefore performed to establish the cancer risk associated with the polymorphism. Methods: In this meta-analysis, a total of 6 case-control studies, including 5,567 cases and 6,191 controls, were included. Crude odds ratios with 95% confidence intervals were used to assess the strength of associations in several genetic models. Results: Our results showed no association reaching the level of statistical significance for overall risk. Interestingly, in the stratified analyses (subdivided by ethnicity), significantly increased risks were found in the Asian subgroup which indicates the TERT rs2736098 polymorphism may have controversial involvement in cancer susceptibility. Conclusions: Overall, this meta-analysis indicates that the TERT rs2736098 polymorphism may have little involvement in cancer susceptibility.