• 품질경영학회지
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• 제25권1호
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• pp.100-115
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• 1997

Shewhart control chart is a basic technique to monitor the state of a process. We observe samples of size four or five and plot some statistic(e.g., mean or range) of each sample on the chart. When setting up the chart, we need to obtain u, pp.r and lower control limits. It is common practice that those limits are calculated from the preliminary 20-40 samples presumed to be homogeneous. However, it may ha, pp.n in practice that the samples are contaminated by outlying observations caused by various reasons. The presence of outlying observations make the control limits wider and hence decrease the sensitivity of the charts. In this paper, we introduce robust control charts with tighter control limits when outlying observations are present in the preliminary samples. Examples will be given via simulation study.

• 품질경영학회지
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• 제46권1호
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• pp.95-112
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• 2018

Purpose: To find out the appropriate probability distribution of credit card usage behavior by considering the relationship among income, expenditure and credit card usage amount. Such relationship is enabled by Korea's especially high penetration of credit card. Method: Goodness-of-fit test and effect size statistic W were used to identify the distribution of income and credit card usage amount. A simulation model is introduced to generate the credit card transactions on individual user level. Result: The three data sets for testing had either passed the chi-square test or showed low W values, meaning they follow the exponential distribution. And the exponential distribution turned out to fit the data sets well. The r values were very high. Conclusion: The credit card usage behavior, denoted as the counts of users by usage amount band, follows the exponential distribution. This distribution is easy to manipulate, has a variety of applications and generates important business implications.

• International Journal of Reliability and Applications
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• 제5권4호
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• pp.105-113
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• 2004

The exponential better (worse) than used EBU (EWU) class of life distributions is considered. A moment inequality is derived for EBU (EWU) distributions which demonstrate that if the mean life is finite, then all moments exist. Based on this inequality, a new test statistic for testing exponentiality against EBU (EWU) is introduced. It is shown that the proposed test is simple, enjoys good power and has high relative efficiency for some commonly used alternatives. Critical values are tabulated for sample sizes n = 5(1)40. A set of real data is used as a practical application of the proposed test in the medical science.

• Ocean and Polar Research
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• 제29권4호
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• pp.391-400
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• 2007

To identify the spatial distribution pattern of water quality in Masan Bay, Pearson's correlation as a common statistic method and Moran's I as a spatial autocorrelation statistics were applied to the hydrological data seasonally collected from Masan Bay for two years ($2004{\sim}2005$). Spatial distribution of salinity, DO and silicate among the hydrological parameters clustered strongly while chlorophyll a distribution displayed a weak clustering. When the similarity matrix of Moran's I was compared with correlation matrix of Pearson's r, only the relationships of temperature vs. salinity, temperature vs. silicate and silicate vs. total inorganic nitrogen showed significant correlation and similarity of spatial clustered pattern. Considering Pearson's correlation and the spatial autocorrelation results, water quality distribution patterns of Masan Bay were conceptually simplified into four types. Based on the simplified types, Moran's I and Pearson's r were compared respectively with spatial distribution maps on salinity and silicate with a strong clustered pattern, and with chlorophyll a having no clustered pattern. According to these test results, spatial distribution of the water quality in Masan Bay could be summed up in four patterns. This summation should be developed as spatial index to be linked with pollutant and ecological indicators for coastal health assessment.

• 문화기술의 융합
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• 제5권2호
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• pp.93-99
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• 2019

본 연구는 대학생의 학과만족도, 자아정체감, 지각된 스트레스와 대학생활 적응 정도를 알아보고, 대학생활 적응에 영향을 미치는 요인을 확인하기 위해 시도되었다. 대학교 신입생 210명을 연구대상으로 구조화된 설문지를 사용하였고, 자료분석은 SPSS/WIN22.0 프로그램으로 하였다. 대학생활적응과 학과만족도(r=.216, p<.001), 자아정체감(r=395, p<.001)은 유의한 상관관계를 보였고, 대학생활적응을 예측하는 모형의 통계적 유의성을 검정한 결과, F 통계값은 12.22, 유의확률은 .000으로 제변수들이 유의수준 0.1에서 대학생활적응을 유의하게 설명하고 있으며, 대학생활적응도를 44%가 제변수에 의해 설명되고 있다. 제변수들을 고려하여 대학생활적응 프로그램을 개발한다면, 대학생들의 적응능력 향상에 긍정적인 효과가 있을 것으로 기대된다.

• 산업융합연구
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• 제21권4호
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• pp.91-100
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• 2023

본 연구는 졸업예정 간호대학생의 전공선택동기와 전공만족도가 간호경력몰입에 미치는 영향을 확인하기 위하여 시행되었다. 이를 위해 간호대학생 4학년 215명의 자료를 수집하였고, SPSS statistics로 t-test, ANOVA, Scheffé test, Pearson correlation coefficients, multiple regression을 사용하여 분석하였다. 연구결과, 간호대학생의 간호경력몰입은 전공선택동기(r=.41, p<.001) 및 전공만족도(r=.35, p<.001)와 정적 상관관계가 있었고, 전공선택동기가 간호경력몰입의 영향요인으로 확인되었으며 설명력은 39.4%였다. 본 연구는 졸업예정 간호대학생의 간호경력몰입 영향요인을 확인하였고, 간호대학생을 위한 긍정적인 간호경력몰입 형성 교육프로그램 개발을 제언한다.

• 한국조리학회지
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• 제18권1호
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• pp.246-258
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• 2012

본 연구의 목적은 대학생들의 교육서비스품질이 교육만족도에 미치는 영향에서 본인참여가 매개효과와 조절효과를 규명함으로써 효율적인 학사관리를 위한 기초자료를 제공하고자 한다. 연구의 목적을 달성하기 위하여 부산지역 외식 조리 전공 2,4년제 대학생 310명을 대상으로 SPSS 18.0 통계 프로그램을 이용하여 빈도분석, 요인분석 상관관계분석을 하였다. 또한 본인참여가 매개효과가 있는지의 검정은 3단계 회귀분석을 실시하였고, 조절효과를 검정하기 위하여서는 위계적 회귀분석을 실시하였다. 분석결과는 교육서비스 품질과 교육만족도간에는 정의 상관관계가 있었으며, 본인참여와는 후생복지 서비스를 제외한 모든 변수에서 정의 상관관계를 나타내었다. 본인참여의 매개효과 분석은 교육서비스품질에 본인참여를 추가하여 교육만족도에 미치는 영향에서 p<0.01에서 통계적으로 유의한 결과를 나타내어서 본인참여는 순수 매개효과가 없는 것으로 나타났다. 본인참여의 조절효과는 $R^2$값이 0.537에서 0.569로 0.032증가하여 교육서비스품질에 본인참여가 교육만족도를 증가시키는 것으로 분석되어 조절효과가 있는 것으로 판단할 수 있다. 하지만 실습실환경${\times}$본인참여는 통계적으로 유의한 결과를 나타내지 않았기 때문에 부분적으로 조절효과가 있는 것으로 있는 것으로 분석되었다.

• Clinical and Experimental Pediatrics
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• 제64권12호
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• pp.632-641
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• 2021

Background: Over the past few decades, various goals have been defined to reduce the mortality of children caused by acute lower respiratory infections (ALRIs) worldwide. However, few spatial studies to date have reported on ALRI deaths. Purpose: We aimed to assess the spatial modeling of mortality from ALRI in children under 5 years of age during 2000-2017 using a global data. Methods: The data on the mortality of children under 5 years old caused by ALRI were initially obtained from the official website of the World Health Organization. The income status of their home countries was also gathered from the Country Income Groups (World Bank Classification) website and divided into 5 categories. After that, in the ArcGIS 10.6 environment, a database was created and the statistical tests and related maps were extracted. The Global Moran's I statistic, Getis-Ord Gi statistic, and geographically weighted regression were used for the analyses. In this study, higher z scores indicated the hot spots, while lower z scores indicated the cold spots. Results: In 2000-2017, child mortality showed a downward trend from 17.6 per 100,000 children to 8.1 and had a clustered pattern. Hot spots were concentrated in Asia in 2000 but shifted toward African countries by 2017. A cold spot that formed in Europe in 2007 showed an ascending trend by 2017. Based on the results of geographically weighted regression test, the regions identified as the hot spots of mortality from ALRI in children under 5 years old were among the middle-income countries (R²=0.01, adjusted R²=8.77). Conclusion: While the total number of child deaths in 2000-2017 has decreased, the number of hot spots has increased among countries. This study also concluded that, during the study period, Central and Western Africa countries became the main new hot spots of deaths from ALRI.

• 한국초지조사료학회지
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• 제31권4호
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• pp.415-422
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• 2011

본 연구는 최근 조사료의 신속한 품질평가 방법으로 근적외선 분광법의 이용성이 확대되고 있는 시점에 근적외선 분광기의 현장 적용성을 평가하기 위하여 수행되었다. 실험실용 근적외선분광기와 소형 근적외선분광기의 조사료 품질평가의 예측 정확성을 평가하기 위하여 전남지역에서 이탈리안 라이그라스 사일리지 67점을 수집하여 각각의 근적외선 분광기를 이용하여 스펙트럼을 측정한 후 사료가치의 실험실 분석값과 다변량회귀분석을 통하여 검량식을 유도하여 예측 정확성을 평가하였다. 이탈리안 라이그라스 사일리지의 수분함량에 대한 예측정확성은 실험실용 근적외선분광기와 소형근적외선분광기에서 각각 SEC = 2.50% ($R^2$=0.96), SEC = 2.83% ($R^2$=0.95)로 매우 신뢰성이 우수한 결과를 나타내었으나 사일리지의 발효품질의 주요 평가항목인 pH와 젖산함량은 실험실용 근적외선분광기의 결과가 SEC = 0.21% ($R^2$=0.82), SEC = 0.24% ($R^2$=0.83)로 소형 근적외선분광기 보다 우수한 결과를 나타내었다. 또한 ADF, NDF 및 조단백질 함량은 실험실용 근적외선분광기의 예측 정확성이 각각 SEC = 0.59% ($R^2$=0.96), SEC = 0.74% ($R^2$=0.97), SEC = 0.67% ($R^2$=0.82)로 높게 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제24권12호
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• pp.1660-1665
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• 2011

This study presents a linkage disequilibrium (LD) analysis and effective population size ($N_e$) for the entire Hanwoo Korean cattle genome, which is the first LD map and effective population size estimate ever calculated for this breed. A panel of 4,525 markers was used in the final LD analysis. The pairwise $r^2$ statistic of SNPs up to 50 Mb apart across the genome was estimated. A mean value of $r^2$ = 0.23 was observed in pairwise distances of <25 kb and dropped to 0.1 at 40 to 60 kb, which is similar to the average intermarker distance used in this study. The proportion of SNPs in useful LD ($r^2{\geq}0.25$) was 20% for the distance of 10 and 20 kb between SNPs. Analyses of past effective population size estimates based on direct estimates of recombination rates from SNP data demonstrated that a decline in effective population size to $N_e$ = 98.1 occurred up to three generations ago.