• The Korean Journal of Applied Statistics
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• v.19 no.1
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• pp.163-170
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• 2006

The argument concerning the choice of effect measure for epidemiologic data or clinic data has been renewed. But the relationships among effect measures can be confusing if effect measures are expressed by conventional mathematical functions alone. In this article, risk difference(RD), relative risk(RR), and odds ratios(OR) for binary data are presented by radar diagram instead of mathematical functions and the relationships among them are showed using radar diagram. This radar diagram is offered flexible conceptual tool to understand effect measures, DR, RR, and OR for binary data.

• Journal of Technology Innovation
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• v.6 no.2
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• pp.178-207
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• 1998

This article suggests a methodology to decide the priority of investment project for venture business under the dynamic circumstance. By the Monte Carlo procedure on the probability distribution of cost and revenue, the model simulates the investment project to estimate profit ratio and risk. The profit ratio is calculated on the yearly basis for the relative comparison. The project risk is calculated as semi-variance under the target yield. After sufficient simulations in this fashion for several projects, the efficient projects with more profit and less risk are selected by the dominance principle. Then the regression equation of the selected projects is produced to find the relative value of the projects. The relative value is obtained through dividing the raw profit ratio by the estimated one on the equation. This value shows the degree to which the simulated project yields over the equation. The priority of investment is decided by this value. An examplary venture business of chemical development for semi-conductor is presented as a case study.

• Journal of Environmental Health Sciences
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• v.32 no.3
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• pp.240-248
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• 2006

The purposes of this study were to investigate the symptoms, diseases and deaths of residents living near the municipal solid waste landfill site, and to compare the relative risk ratio of their adverse health effects with control group. In self-evaluation, the scores were especially severe lowest in residents of v2 and v3 villages(which were located about 500 m toward under the landfill site) such as 32.2 and 16.7 for village-environment, 24.8 and 16.0 for management of landfill site, and 23.5 and 16.5 for confidence of environmental policy, respectively. On symptoms, relative risk ratios were also highest as 3.53 and 3.55 for breathing difficulty, and 3.36 and 3.00 for respiratory symptom in v2 and v3 villages, respectively. On morbidity, they were slightly high as much as 1.39 and 1.24 in v5 and v2 villages, respectively. On mortality, relative risk ratios were $1.15{\sim}2.46$ in experimental villages. They were especially high as much as 2.46 in v3 village where located near under the landfill site, and also 2.14 in v5 village where located at area affected with the landfill site, but near the sea. The rate of cancer causing death was average 35.2% of total deaths. It was very highest as much as 61.1 % in v2 village, where was closely located near under the landfill site. Cancers causing death in this village were lung cancer(3 cases), larynx cancer(2 cases), stomach cancer(2 cases), pancreatic cancer(1 case), thryoid cancer(1 case), leukemia(1 case) and other(1 case). Our data, although based on limited number of cases and geographical coverage, suggest that residents living near landfill site have the increasing relative risks of various symptoms and mortality causing cancer. No causal mechanisms are available to explain these findings. But the possibility of a causal association between the increased adverse health effects and the municipal solid waste landfill site cannot be fully excluded.

• Communications for Statistical Applications and Methods
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• v.11 no.1
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• pp.181-187
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• 2004

One of objectives in epidemiologic studies is to detect the amount of change caused by a specific risk factor. Risk ratio is one of the most useful measurements in epidemiology. When we perform the inference for this measurement with rare events, the standard approach based on the normal approximation may fail, in particular when there are no disease cases observed. In this paper, we discuss and evaluate several existing methods for constructing a confidence interval of risk ratio through simulation when the disease of interest is a rare event. The results in this paper provide guidance with how to construct interval estimates for risk difference and risk ratio when there are no disease cases observed.

• The Journal of Korean Medicine
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• v.24 no.4
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• pp.1-5
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• 2003

Leptin has a close correlation with obesity, which is known to be a major factor for stroke. This study was performed to determine whether serum leptin level would be an independent risk factor for stroke and whether it would change significantly early after stroke. Subjects were selected from those within I month after onset and non-stroke referents at Kyung Hee Oriental Medical Center in Seoul, Korea. We compared leptin and the other characteristics between stroke subjects and referents. Body mass index, hypertension history, presence of drinking and smoking, waist/hip ratio, total cholesterol and triglyceride were recorded. To assess odds ratio of leptin for stroke, we used logistic regression analysis. Leptin was rechecked 2 weeks later and compared with the former value in acute stroke subjects. In this study, serum leptin did not differ significantly between stroke subjects and referents, and its odds ratio was not significant in male (OR=0.52, 95％ Cl; 0.13-2.08) and female (OR=1.57, 95％ Cl; 0.53-4.67). In acute stroke subjects, leptin did not change significantly 2 weeks later. Hypertension had a significant odds ratio in male (OR=3.39, 95％ Cl; 1.02-11.24) and female (OR=12.37, 95％ Cl; 3.67-41.65). High waist/hip ratio was only in female (OR=6.70, 95％ Cl; 1.73-26.02). In conclusion, leptin was not an independent risk factor for stroke and its serum level did not change significantly early after stroke. Hypertension and waist/hip ratio had significant relative risks.

• Journal of Korean Academy of Nursing
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• v.44 no.6
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• pp.743-750
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• 2014

Purpose: The objective of this study was to provide a trend analysis of the prevalence of diabetes relative to the socioeconomic, lifestyle, and physiologic risk factors among Korean adults aged over 30 years for a 10-year period using data from the Korean National Health and Nutrition Examination Survey. Methods: Prevalence difference and the slope index of inequality were calculated for each risk factors using binomial regression by considering the repeated cross-sectional features of the data. The prevalence ratio and the relative index of inequality were calculated using log-binomial regression. Linear trend tests were performed using SAS 9.2. Results: Crude prevalence of diabetes increased over the 10-year period, and was higher for men than for women. It was very high for adults 60 years or over, consistently increasing over time. The prevalence among unemployed men, women with higher level of stress, women with hypertension, and adults with serum triglyceride levels over 135 mg/dL increased over the 10-year period in comparison with the respective control group. Conclusion: Considering the rapid economic development and associated lifestyle changes in Korea, action should be taken to control the prevalence of diabetes by both preventing and consistently monitoring these identified risk factors using a public-health approach.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.841-851
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• 2019

This study presents risk ranking by accident types at intersections, crosswalk and tunnel sections. An ordered logit model was used to estimate the accident severity of traffic accidents based on 58,868 accident records that have occurred on the Seoul and Gyeonggi-do over the period 2014-2017. The factors affecting the injury severity were identified by the estimated model first, and risk ranking was proposed according to conditions of accident occurrence using relative ratio analysis later. The analysis results showed that the injury severity dramatically depends on the location and time of the accident. The analysis results showed that the injury severity dramatically depends on the location and time of the accident. Furthermore, there are severe injury cases in terms of the injury severity despite the small number of occurrence of traffic accident, or there are severe injury cases in terms of the injury severity despite the high frequency of occurrence of traffic accident.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2429-2434
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• 2016

Transforming growth factor-B1 ($TGF-{\beta}1$ )and its coreceptor endoglin (ENG) have been shown to contribute to hepatocellular tumor development and malignant progression. Our aim was to evaluate the serum expression levels of $ENG/TGF-{\beta}1$ mRNAs and risk of hepatocellular carcinoma in cirrhotic Egyptian patients. Our study included 77 subjects. Real time polymerase chain reaction was used to evaluate the expression level of ENG and $TGF-{\beta}1$mRNAs. The relative expression ratio of ENG mRNA was 0.82 (0.1 -3.2), 0.66 (0.15-5.3), 0.38(0.007-2.8) and 0.12 (0.00-0.22) and the relative expression ratio of $TGF-{\beta}1$mRNA was 1.4 (0.19 -6.2), 1.2 (0.22-4.3), 1.0 (0.15-4.4) and 0.6 (0.00-2.2) for cirrhotic HCC cirrhotic, HCC only and healthy control groups respectively. Increased ENG and $TGF-{\beta}1$ mRNA gene expression was correlated with TNM clinical stage. The expression ratio in TNM stage III-IV 1.1 (0.07-3.2), 1.55 (0.15-6.2) was statistically significantly higher than that in stage I-II 0.47 (0.007-2.8), 1.0 (0.31-4.4) (P<0.05). Our data suggested that increased ENG and $TGF-{\beta}1$ gene expression may participate in hepatocarcinogenesis and increased risk of HCC in individuals with cirrhosis. Early screening for evidence of cirrhosis and consideration of ENG and $TGF-{\beta}1$ as targets for therapy and treatment strategies are warranted.

• The Korean Journal of Applied Statistics
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• v.18 no.1
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• pp.27-41
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• 2005

We made a new sample design for intestinal parasitic infection survey in 2004. We used the 10% sample survey data of 2000 population and housing census as a survey population. Since the infection rates of intestinal parasitics are very low, we applied the relative risk and odds ratio instead of ordinary method such as t-test to study the characteristics from the 1997 survey data. In order to allocate samples to stratum, we used the compromise of Neyman allocation which is the average of three Neyman allocations. And also, we derive estimators and variance estimators of the estimators.

• International Journal of Reliability and Applications
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• v.16 no.2
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• pp.55-79
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• 2015

It is well known that using any additional information in the estimation of unknown parameters with new sample of observations diminishes the sampling units needed and minimizes the risk of new estimators. There are many rational reasons to assure that the existence of additional information in practice and there exists many practical cases in which additional information is available in the form of target value (initial value) about the unknown parameters. This article is described the problem of how the prior initial value about the unknown parameters can be utilized and combined with classical Bayes estimator to get a new combination of Bayes estimator and prior value to improve the properties of the new combination. In this article, two classes of Bayes-shrinkage and preliminary test Bayes-shrinkage estimators are proposed for the scale parameter of exponential distribution. The bias, risk and risk ratio expressions are derived and studied. The performance of the proposed classes of estimators is studied for different choices of constants engaged in the estimators. The comparisons, conclusions and recommendations are demonstrated.