• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.419-428
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• 2005

The aim of this study was to provide data for the relief of asthenopia during binocular vision by determining the characteristics of ocular function in adults. A total of 260 subjects were between the age of 19-35years. We measured individually the refractive error correction, pupillary distance, optical center distance, phoria, convergence, accommodation and the AC/A as well as the asthenopia during binocular vision using a questionnaire. After analysis of factors affecting asthenopia, we also examined the reductive effect of asthenopia in subjects who had asthenopia using prism. To determine the factors affecting asthenopia during binocular vision, statistic analyses were carried out the multivariate Logistic regression model. The results of this study were as follow. The asthenopia during binocular vision was found 26.9% of subjects. Multivariate logistic regression model was used to determine factors affecting binocular vision of myopia. When the accommodation and convergence were low compared to being high, when subjects had esophoria or there was more exophoria, and when AC/A was lower than the standard, the rate of asthenopia was higher. Therefore the accommodation, convergence and AC/A could be predictive factors for asthenopia. We used prism for subjects who had asthenopia during binocular vision, the results showed that the symptom of asthenopia was eased up to 74.3%.

• Journal of Preventive Medicine and Public Health
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• v.36 no.3
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• pp.279-288
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• 2003

Objectives : Evidence for an effect of rerroductive factors on colorectal carcinogenesis is not yet consistent. Little research has been conducted to investigate whether reproductive factors were associated with colorectal adenomas that are the precursors of colorecta1 cancer, We evaluated the relationships between reproductive factors and the degree of dysplasia of the colorectal adenoma and cancer as colorectal adenoma-carcinoma sequence. Methods : For this study, 241 adenoma cases with histopathologically confirmed incident colorectal adenoma, 76 cancer cases with colorectal cancer and 1677 controls were collected from Our Lady of Mercy Hospital, The Catholic University of Korea, during 1994-1999. Before colonoscopy, information on demographic characteristics, reproductive factors, life style habits and dietary intake were obtained by interviewed questionnaire. Adjusted OR and 95% CI were estimated by using polytomous logistic regression model, Potential confounders that were selected based on the goodness of fit Statistics and interaction between risk factors were considered in this adjustment. The Wald statistic was calculated to test the heterogeneity of the odds ratios for each case. Results .: Postmenopausal women with natural menopause were found to be positively associated with the risk of mild dysplasia adenoma (multivariate-adjusted OR : 2.59, 95% CI=1.1-0.2). Parity was found to be negatively associated with the risk of colorectal lancer (age-adjusted OR : 0.40, 95% CI=0.2-0.9), but did not significantly decrease the risk of colorectal cancer (multivariate-adjusted OR : 0.95, 95% CI=0.3-2.9). Me associations were seen between a9e at menarche, breast feeding, induced abortion, oral contraceptive use, menopausal types, menopausal age or hormone replacement therapy (HRT and the degree of dysplasia of the colorectal adenoma and cancer. However, none of these associations differed' significantly between the degree of dysplasia of the colorectal adenoma and cancer. Conclusions : These findings suggest that postmenopausal women with natural menopause may experience increased risk of mild dysplasia adenorna among colorectal adenoma-carcinoma sequence.

• Journal of Preventive Medicine and Public Health
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• v.34 no.3
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• pp.244-252
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• 2001

Objective : Health insurers and policy makers are increasingly examining the hospital mortality rate as an indicator of hospital quality and performance. To be meaningful, a risk-adjustment of the death rates must be implemented. This study reviewed 5 severity measurement methods and applied them to the same data set to determine whether judgments regarding the severity-adjusted hospital mortality rates were sensitive to the specific severity measure. Methods : The medical records of 584 patients who underwent coronary artery bypass graft surgery in 6 general hospitals during 1996 and 1997 were reviewed by trained nurses. The MedisGroups, Disease Staging, Computerized Severity Index, APACHE III and KDRG were used to quantify severity of the patients. The predictive probability of death was calculated for each patient in the sample from a multivariate logistic regression model including the severity score, age and sex to evaluate the hospitals' performance, the ratio of the observed number of deaths to the expected number for each hospital was calculated. Results : The overall in-hospital mortality rate was 7.0%, ranging from 2.7% to 15.7% depending on the particular hospital. After the severity adjustment, the mortality rates for each hospital showed little difference according to the severity measure. The 5 severity measurement methods varied in their statistical performance. All had a higher c statistic and $R^2$ than the model containing only age and sex. There was a little difference in the relative hospital performance evaluation by the severity measure. Conclusion : These results suggest that judgments regarding a hospital's performance based on severity adjusted mortality can be sensitive to the severity measurement method. Although the 5 severity measures regarding hospital performance concurred, more often than would be expected by chance, the assessment of an individual hospital mortality rates varied by the different severity measurement method used.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1451-1462
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• 2007

Heavy metal concentrations in the soil were investigated for the abandoned Samkwang metal mine, Cheongyang-Gun, Chungnam Province, Korea. The concentrations of heavy metal(As, Cd, Cu, Ni, Pb, Zn) were determined in mine soils collected at the abandoned mine sites to obtain a general classification and specification of the pollution in this highly polluted region. The results estimated with the normal test and basis statistic on the central tendency and variation showed that the distribution of heavy metal concentration had significantly different at the range of all locations. The range of spatial distribution on the relationship of heavy metal concentration and pH was $4.8{\sim}8.8$ and heavy metal concentration on the type of land use was highest in forest land, and also Ni and Zn in farm and rice field showed the high concentration. The distribution of heavy metal concentration on the depth of a soil showed that the metal concentrations in subsoil were higher than of those in surface soil, while the concentration of Cu and Ni had no significant difference on the depth of soil. Results from the correlation analysis using the data except the extreme and unusual data revel that Zn-Cd(r=0.867), Zn-As(r=0.797), Zn-Pb(r=0.764), Cu-Cd(r=0.673), Cu-As(r=0.614) and Zn-Ni(r=0.605) were the most important parameters in assessing variations of heavy metal in soil. To discriminate pattern differences and similarities among samples, principal factor analysis(PFA) and cluster analysis(CF) were performed using a correlation matrix. This study suggests that PFA and CF techniques are useful tools for identification of important heavy metal and parameters. This study presents the necessity and usefulness of multivariate statistical assessment of complex databases in order to get better information about the quality of soil and gives the basis information to clean up the abandoned mine sites.

• Journal of the Korean Data and Information Science Society
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• v.28 no.1
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• pp.87-98
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• 2017

The multivaiate empirical distribution function (MEDF) is defined in this work. The MEDF's expectation and variance are derived and we have shown the MEDF converges to its real distribution function. Based on random samples from bivariate standard normal distribution with various correlation coefficients, we also obtain MEDFs and propose two kinds of graphical methods to visualize MEDFs on two dimensional plane. One is represented with at most n stairs with similar arguments as the step function, and the other is described with at most n curves which look like bivariate quantile vector. Even though these two descriptive methods could be expressed with three dimensional space, two dimensional representation is obtained with ease and it is enough to explain characteristics of bivariate distribution functions. Hence, it is possible to visualize trivariate empirical distribution functions with three dimensional quantile vectors. With bivariate and four variate illustrative examples, the proposed MEDFs descriptive plots are obtained and explored.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.2
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• pp.134-145
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• 2018

Purpose: The purpose of this study was to investigate gender related factors that influence regular exercise adherence in patients with coronary artery disease. Methods: This secondary analysis study used data from the 2013~2015 Korea National Health and Nutrition Examination Survey (KNHANES). Three hundred and eighty patients over 20 years of age and having coronary artery disease were selected for this study. Measures included questions about regular exercise, general characteristics, health behaviors, and health status. Data were analyzed using descriptive analysis, Rao-Scott $x^2$ statistic, and multiple logistic regression analysis with the SPSS 21.0 program. Results: The results were as follows. Men did more regular exercise than women (58.8% vs 40.1%). The multivariate-adjusted Odds Ratios (OR) for regular exercise adherence in men were 2.93 (95% CI: 1.39~6.17) for non smokers and 3.06 (95% CI: 1.53~6.13) for men with 0 to 1 comorbidities. Women had a high odds ratios of 0.38 (95% CI: 0.18~0.82) for not using alcohol and 2.10 (95% CI: 1.03~4.29) for no back pain. Conclusion: To improve regular exercise adherence in patients with coronary artery disease, it is necessary to develop different approaches considering gender.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.93-99
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• 2016

Completeness is an important indicator of data quality in cancer registry programs. This study aimed to estimate the completeness of registered cases in a population based cancer registry program implemented in five provinces of Iran. Capture-recapture methods were used to estimate the number of cases that may have been missed and to estimate rates of completeness for different categories of age, year, and sex. The data used for this study were obtained from three sources: 1) National Pathology Database; 2) National Hospital Discharge Database; and 3) National Death Registry Database. The three sources were linked and duplicates were identified based on first name, last name, father's names, and date of birth, ICD code, and case's residency address using Microsoft Excel. Removing duplicates, the three sources reported a total of 35,643 cases from March 2008 to March 2011. Running many different multivariate models of capture-recapture and controlling for source dependencies revealed an overall under-reporting of 49% in all five registries combined. The estimated completeness differed based on age, sex, and year. The overall completeness was higher for males than females (71.2% for males and 59.9% for females). Younger age had lower rates of completeness compared to older age (38.1% for <40 years, 55.4% for 40-60 years, and 76.7 for >60 years). The results of this study indicated a moderate to severe (depending on the age, sex and year) degree of completeness in the population based cancer registration of Iran.

• The Journal of Fisheries Business Administration
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• v.49 no.2
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• pp.21-35
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• 2018

Squid is a popular seafood in Korea. However, since the 2000s, the squid production has been declining. The unstable supply of the squid products may cause price fluctuations of fresh and chilled squid. These price fluctuations may be relatively more severe than them of other commodities, because the fresh and chilled squid can not be stored for a long period of time. Thus, this study analyzes the structural characteristics of price volatility and price asymmetry of fresh squid based on off-diagonal GARCH model. Data used to analysis of this study are daily wholesale and retail prices of fresh squid from January 1, 2006 to December 31, 2016 provided in the KAMIS. As theoretical approaches of this study, first of all, the stability of the time series is confirmed by the unit root test. Secondly, the causality between distribution channels is checked by the Granger causality test. Thirdly, the VAR model and the off-diagonal GARCH model are adopted to estimate asymmetry effect and price volatility spillover between distribution channels. Finally, the stability of the model is confirmed by multivariate Q-statistic and ARCH-LM test. In conclusion, fresh squid is found to have shock and volatility spillover between wholesale and retail prices as well as its own price. Also, volatility asymmetry effect is shown in own wholesale or retail price of fresh squid. Finally, this study shows that the decrease in the fresh squid retail price of t-1 period than the increase in the t-1 period has a greater impact on the volatility of the fresh squid wholesale price in t period.

• The Journal of the Korea Contents Association
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• v.16 no.11
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• pp.38-52
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• 2016

This study analyzed effects of Action Learning approach on enhancing learning motivation and improving problem-solving capacity in NCS vocational competency classes of Polytechnic College. Targeted group is B Polytechnic College located in Chungnam, and 53 students in experimental group and 64 students in control group. analysis of data is descriptive statistic analysis and the multivariate analysis of variance (MANOVA) method to study sub factors of learning motivation and problem-solving ability. As a result, Action Learning approach has a great influence on connection, confidence, and satisfaction, among the sub factors of learning motivation. also figured that the approach has positive effects on problem clarifying, cause analysis, alternative developing, planning/practicing, and performance assessment, among the sub factors of problem-solving capacity. Moreover, Polytechnic College's NCS vocational competency classes are desirably required to adopt the approach of Action Learning for their educational method, as it fosters basic competencies, such as understanding of diverse perspectives, communicating, leadership, interpersonal relationship, self-development, coping with conflicts, operating meetings, to be learned while students are doing problem-solving activities under a team-working atmosphere.

• Journal of Wetlands Research
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• v.15 no.3
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• pp.329-337
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• 2013

This study was performed to evaluate the temporal and spatial variations of the water quality at stream flowing into the Suncheon bay in Suncheon city from October 2008 to August 2009 and to estimate the pollutant sources from the streams using multivariate analysis. Water qualities from Seo stream, Dong stream, Ok stream were evaluated as I grade(very good) that compared to the Water Quality Standard. But Haeryong stream and inlet site of Suncheon Bay in BOD were evaluated as a little bad and fair. Water quality at the stream flowing into the Suncheon Bay was could be explained up to 92.8% by three factors which were included in loading of nutrients, organic matter and total coliform group by the allochthonous matters(53.7%), Topographic Factors(25.0%), seasonal variation(14.2%). The concentrations of total nitrogen and phosphorus at sewage treatment plant and organic matters at Haeryong stream were higher than that of others, respectively. From principal component analysis and factor analysis, it could be suggested that it is very important to make an effort to reduce the nutrients and organic matters from sewage treatment plant and Haeryong stream to be in good conservation of the Suncheon bay.