• Journal of Preventive Medicine and Public Health
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• 제46권2호
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• pp.96-104
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• 2013

Objectives: The inherent nature of the Korean National Health and Nutrition Examination Survey (KNHANES) design requires special analysis by incorporating sample weights, stratification, and clustering not used in ordinary statistical procedures. Methods: This study investigated the proportion of research papers that have used an appropriate statistical methodology out of the research papers analyzing the KNHANES cited in the PubMed online system from 2007 to 2012. We also compared differences in mean and regression estimates between the ordinary statistical data analyses without sampling weight and design-based data analyses using the KNHANES 2008 to 2010. Results: Of the 247 research articles cited in PubMed, only 19.8% of all articles used survey design analysis, compared with 80.2% of articles that used ordinary statistical analysis, treating KNHANES data as if it were collected using a simple random sampling method. Means and standard errors differed between the ordinary statistical data analyses and design-based analyses, and the standard errors in the design-based analyses tended to be larger than those in the ordinary statistical data analyses. Conclusions: Ignoring complex survey design can result in biased estimates and overstated significance levels. Sample weights, stratification, and clustering of the design must be incorporated into analyses to ensure the development of appropriate estimates and standard errors of these estimates.

• Journal of the Korean Statistical Society
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• 제30권4호
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• pp.661-666
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• 2001

In this paper we consider an M/G/1 queue where the server of the system has a vacation time and the service policy is limited-1. In this system, upon termination of a vacation the server returns to the queue and serves at most one message in the queue before taking another vacation. We consider two models. In the first, if the sever finds the queue empty at the end of a cacation, then the sever immediately takes another vacation. In the second model, if no message have arrived during a vacation, the sever waits for the first arrival to serve. The analysis of this system is particularly useful for a priority class polling system. We derive Laplace-Stieltjes transforms of the waiting time for both models, and compare their mean waiting times.

• Journal of the Korean Data and Information Science Society
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• 제14권1호
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• pp.113-118
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• 2003

In this paper, We assume that strengths of two components system follow a bivariate pareto distribution. And these two components are subjected to a common stress which is independent of the strength of the components. We obtain maximum likelihood estimator(MLE) for the system reliability from stress-strength relationship. Also we derive asymptotic properties of the MLE and present a numerical study.

• 한국물환경학회지
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• 제24권6호
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• pp.725-740
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• 2008

In this study a multi-site daily precipitation generator which generates the precipitation with similar spatial correlation, and at the same time, with conserving statistical properties of the observed data is developed. The proposed generator is intended to be a tool for down-scaling the data obtained from GCMs or RCMs into local scales. The occurrences of precipitation are simultaneously modeled in multi-sites by 2-parameter first-order Markov chain using random variables of spatially correlated while temporally independent, and then, the amount of precipitation is simulated by 3-parameter mixed exponential probability density function that resolves the issue of maintaining intermittence of precipitation field. This approach is applied to the Nakdong river basin and the observed data are daily precipitation data of 19 locations. The results show that spatial correlations of precipitation series are relatively well simulated and statistical properties of observed precipitation series are simulated properly.

• 한국데이터정보과학회:학술대회논문집
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• 한국데이터정보과학회 2006년도 PROCEEDINGS OF JOINT CONFERENCEOF KDISS AND KDAS
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• pp.307-315
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• 2006

현대 사회에 있어서 신속하고 정확한 정보는 곧 수익증대의 중요한 요소로 자리 잡고 있으며 사회발전이 가속화 될수록 더욱 다양한 정보가 산출되고 있다. 그로인하여 광범위하게 분산되어 있는 정보의 추출은 매우 중요한 부분으로 부각되고 있다. 하지만 기존의 자료 집계 방법은 분산되어 있는 자료를 수집하기 위한 시간이 많이 소요되고 수집된 자료의 확인과정 및 통합 과정 또한 많은 시간이 소요되어 현대의 수많은 정보를 효율적으로 수용하지 못하고 있다. 이에 본 논문에서는 광범위하게 분산되어 있는 자료들에 대하여 효율적인 정보 추출을 제공할 수 있는 자료 집계 및 분석 시스템의 설계 및 구현 방안에 대하여 연구하고자 한다.

• 산업경영시스템학회지
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• 제42권3호
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• pp.95-108
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• 2019

Quality management has become an pervasive philosophy in most sectors of business. Specific movements such as statistical quality control, quality circle, total quality management, and quality management system have become embedded in business organizations. Only the companies with competitive edge can survive in the competition in global market. KSA(Korean Standards Association) established in 1962 has launched all kinds of quality education, quality standard certification service for business, and KNQA(Korean National Quality Award) system. This article considers quality competitiveness excellent company award among KNQA. We performed a statistical analysis of audit data for quality competitiveness excellent company for three years, from 2015 to 2017. By using ANOVA and two sample t-tests, the average scores of 13 evaluation fields were significantly different depending on company size and type. We proposed ways to improve the current hall of fame system. We discovered that the average scores of 13 evaluation fields in the audit data according to years and hall of fame status were not significantly different. We also showed linear relationships among 13 evaluation fields by correlation analysis and obtained an estimated linear regression equation : Business Performance, which is a comprehensive index, as a dependent variable was significantly related to Customer Focus and Product Liability as regressor variables among 13 evaluation fields by regression analysis.

• 융복합기술연구소 논문집
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• 제2권2호
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• pp.55-58
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• 2012

The strategic industry in Chungbuk province is the electric and electronic related industry. In the Chnugju region, the trend of major industry have change from the electric and electronic related industry to mechanical parts and components related industry include manufacturing of automobile and transportation. In this paper, we perform statistical analysis using the micro data service provided by the Statistics Korea, The CAGR of the number of employee and value-added value in the electric and electronic related industry during past 7 years are -7.1% and -13.2%, respectively while the CAGR in the mechanical parts related industry are 14.4% and 22.9%, respectively. However, value-added value per value of shipment of the mechanical related industry is lower than that of the electric and electronic related industry.

• 대한임상검사과학회지
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• 제43권2호
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• pp.48-56
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• 2011

Gastrointestinal stromal tumor (GIST) is a mesenchymal tumor and is associated with a specific immunophenotype index. It is very important to identify the specific immunophenotype and the diagnosis for the treatment GIST patients. Ninety two cases of GIST analyzed in this study were immuno-stained for c-kit, DOG1, CD34, PKC-${\theta}$, PDGFR-${\alpha}$. The rate of positive staining and statistical significance were then compared. In addition, the GISTs were analyzed as followings: very low risk, low risk, intermediate risk and high risk according to tumor size and nuclear division, and later correlated with clinical parameters. The results of the GIST positive stainings were: DOG1 (95.7%), PKC-${\theta}$ (90.2%), PDGFR-${\alpha}$ (88.0%), c-kit (87.0%) and CD34 (71.7%). Only DOG1 staining showed a statistical significance of p<0.05. It was identified in the classification system of histologic risk that staining expression of DOG1, PKC-${\theta}$, PDGFR-${\alpha}$ were significantly increased as histologic risk increases (p<0.05). However, clinical parameters such as age and sex of patients have no correlations with the classification system of histologic risk (p>0.05). Therefore, in this study, the expression of DOG1 showed statistical significance and DOG1, PKC-${\theta}$, PDGFR-${\alpha}$ staining increased significantly as the histologic risk increases in histologic classification system. Taken together, the DOG1 staining should be very effective for the diagnosis of GIST patients.

• 한국물환경학회지
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• 제23권5호
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• pp.740-747
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• 2007

The advanced wastewater treatment plant of leather industry was selected to evaluated with its effluent water quality and statistical characteristics. Most of pollutants removal efficiencies were over 90% as well. And 95% reliability of effluent concentration were 106.8 mg/L of $COD_{mn}$, 72.04 mg/L of TN. However Effluent quality of TN exceeds the regulated limit. The range of coefficient of variation (CV) were between 0.18 and 2.49. Also, coefficient of reliability (COR) were between $0.03(BOD_5){\sim}0.63(COD_{mn})$ and 0.43 in terms of T-N, $Z_{l-a}$(Normalized Percentiles) value were 55.7 and 2.25 in terms of $BOD_5$ and T-N as shown in the following table.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2006년도 임시총회 및 추계학술발표회
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• pp.82-84
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• 2006