• Journal of the Korean Society of Physical Medicine
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• v.12 no.2
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• pp.9-20
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• 2017

PURPOSE: The purpose of this study is to understand the difference in the risk factors of coronary artery disease (CAD) between Korean and American CAD patients to determine the discriminant factor for each group, as well as to provide useful information to be reflected in the national concern of health. METHODS: Data were collected from 248 Korean and 107 American CAD patients who underwent either percutaneous coronary intervention or coronary artery bypass grafting. By using t-test and $X^2$-test, risk factors were compared between the Koreans and Americans. To elucidate which risk factor was the most discriminant for each group, logistic regression analysis was performed. RESULTS: All risk factors, except diastolic blood pressure, showed a significant difference between the two groups. $X^2$-test showed statistical significance with respect to the smoking rate between the female groups. Moreover, there was a statistically significant difference between the two groups regarding blood total cholesterol (TC) and triglyceride, and between the male groups, here was a statistically significant difference with respect to blood high-density lipoprotein cholesterol (HDL). Diabetes mellitus (DM) was the most discriminant factor for Korean patients while TC/HDL is the most discriminant for the Americans. CONCLUSION: The characteristics of CAD risk factors were determined to be different between Koreans and Americans in this study. TC/HDL was a discriminant factor for Americans while DM was a discriminant factor for Koreans. This result implies that DM should primarily be given attention to prevent CAD in Korean adults.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.2
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• pp.53-57
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• 2017

PURPOSE: The purpose of study was to clear up the environmental risk factor that can be easily occurred unstability of hip during gait and one leg standing at various ramp angle. METHODS: Twenties healthy males of 69 subjects is participated in this study. Participants was measured activation on gluteus medius muscle during both conditions (walk across the ramp and one leg stand in the transverse direction) of seven different angle. The measured data were analyzed using one-way ANOVA to investigate the effect of muscle activation on the each condition. The statistical analyses were performed using SPSS ver. 18.0 and p-value less than .05 were considered significant for all cases. A post-hoc test was performed by Bonferoni method. RESULTS: The study showed that more muscle activities on gluteus medius is increased by increasing the ramp angle. Post-hoc analysis demonstrated that the peak and mean of muscle activity increased significantly with a ramp angle of $15^{\circ}$ and $25^{\circ}$ during gait and one-leg stand. CONCLUSION: According to the study results, impaired balance can be easily occurred when cross walk and one-leg stand on a ramp from higher than $15^{\circ}$, and highest risk was angle of $25^{\circ}$ or more. As a people with gluteus medius muscle weakness walks a ramp, the ramp angle has a cross relationship with the impaired balance. If people with gluteus medius weakness walk on the more than $10^{\circ}$ of ramp angle, they will need a lot of attention for prevent impaired balance.

• Journal of Preventive Medicine and Public Health
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• v.38 no.1
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• pp.38-44
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• 2005

Objective : To compare the mortality rate of Korean medical doctors to that of the general Korean population for the period 1992-2002. Methods : The membership records of the Korean Medical Association were linked to the 1992-2002 death certificate data of Korea s National Statistical Office using 13-digit unique personal identification numbers. The study population consisted of 61,164 medical doctors with a follow-up period of 473,932 person-years. Standardized mortality ratios(SMRs) were calculated to compare cause-specific mortality rates of medical doctors to those of the general population. Results : We confirmed 1,150 deaths at ages from 30 to 75 years from 1 January 1992 to 31 December 2002. The SMR for all-cause of death was 0.47(95% CI : $0.44{\sim}0.50$). The SMRs for smoking-related diseases such as cerebrovascular accidents and chronic obstructive pulmonary disease were smaller than the SMR of all-cause of death. However, the SMRs for colorectal and pancreatic cancers were not significantly lower than those of the general population. Transport accidents and suicides accounted for 72% (94 of 131) of external causes of death. The SMR for suicide was 0.51 (95% CI : $0.38{\sim}0.68$). Conclusions : The mortality rate of South Korean medical doctors was less than 50% that of the general population of South Korea. Cause-specific analysis showed that mortality rates in leading causes of death were lower among medical doctors although differences in mortality rates between medical doctors and the general population varied with the causes of death. These health benefits found among medical doctors may be attributable to the lower level of health damaging behaviors (e.g., lower smoking rates) and better working conditions.

• The Journal of Korean Physical Therapy
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• v.21 no.2
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• pp.103-108
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• 2009

Purpose: Electrical stimulation is one of several treatments recommended for RA patients. Electrical stimulation of RA patients, reduces pain, or facilitates joint motion prior to exercises. However, there is still limited evidence on the efficacy of electrical stimulation and thus any conclusions drawn about this method remain controversial. Recently, Microcurrent Electrical Neuromuscular Stimulation (MENS) has received significant attention as a potential method of electrical stimulation. In this study, we investigated the effect of microcurrent treatment in rheumatoid arthritis rat. Methods: Subjects were allocated either to the control group or experimental group, which was subject to microcurrent stimulation. Interleukin-1 expression in the metatarsophlangeal joint and the oedema index in the ankle were used for classification and subsequent evaluation of pathology. Subjects were assessed at 1, 7 and 14 days after inducing rheumatoid arthritis through adjuvant injection. Thirty-six subjects, 18 in each group, were used in this study. Statistical analysis was performed by calculating the differences between the two groups and between each interval assessment. Categorical variables were compared between the two groups with the paired-T test. The one-way ANOVA test was performed to assess changes in ordinal variables. Results: Baseline characteristics were similar in both groups. Statistically significant differences were found between the two groups. The biological marker of pro-inflammatory cytokine and oedema index were decreased in response to this treatment. Conclusion: These data show that treatment of rheumatoid arthritis with a microcurrent stimulation device reduced the oedema index and pro-inflammatory cytokine IL-1.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.61-73
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• 2016

We consider the wild bootstrap Ljung-Box (LB) test for autocorrelation in residuals of fitted multivariate time series models. The asymptotic chi-square distribution under the IID assumption is traditionally used for the LB test; however, size distortion tends to occur in the usage of the LB test, due to the conditional heteroskedasticity of financial time series. In order to overcome such defects, we propose the wild bootstrap LB test for autocorrelation in residuals of fitted vector autoregressive and error correction models. The simulation study and real data analysis are conducted for finite sample performance.

• The Korean Journal of Applied Statistics
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• v.27 no.2
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• pp.291-305
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• 2014

Persistence is one of the typical characteristics appearing in the volatility of financial time series. According to the recent researches, the volatility persistence may be due to either volatility shifts or long-range dependence. In this paper, we consider residual-based CUSUM tests to distinguish volatility persistence, long-range dependence and volatility shifts in GARCH models. It is observed that this test procedure achieve reasonable powers without a size distortion. Moreover, we employ AIC and BIC criteria to estimate the change points and the number of change points in volatility. We demonstrate the superiority of residual-based CUSUM tests on various Monte Carlo simulations and empirical data analysis.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.1
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• pp.59-67
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• 2016

Owing to time and cost constraints, new methods that would make it possible to evaluate the safety of the water supply pipeline in a less time- and cost-consuming manner are urgently needed. In response to this exigency, the present study developed a new statistical model to assess the safety of the water supply pipeline using the quantification theory type II. In this research, the safety of the water supply pipeline was defined as 'a possibility of the pipeline failure'. Quantification analysis was conducted on the qualitative data, such as pipe material, coating, and buried condition. The results of analyses demonstrate that the hit ratio of the quantification function amounted to 77.8% of hit ratio, which was a fair value. In addition, all variables that were included in the quantification function were logically valid and demonstrated statistically significant. According to the results derived from the application of the safety evaluation model, the coefficient of determination ($R^2$) between K-region's water supply pipeline safety and the safety inspection amounted to 0.80. Therefore, these findings provide meaningful insight for the measured values in real applications of the model. The results of the present study can also be meaningfully used in further research on safety evaluation of pipelines, establishing of renewal prioritization, as well as asset management planning of the water supply infrastructure.

• 한국해양학회지
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• v.21 no.4
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• pp.245-258
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• 1986

A two-dimensional numerical model is developed to investigate the phenomenon of forced seiche caused by the incident long waves. This model is applied to Young-il Bay and Pohang New Harbor, where the seiche is most frequently observed and the damage of the seiche is serious compared with the other harbors in Korea. Some results on this study are as follows; 1. The natural periods of the first two modes obtained from the present model are about 70 and 25 minutes respectively for Young-il Bay, and about 25 and 7.5 minutes for Pohang New Harbor. These results are well consistent with those obtained by the theoretical formula, the spectral analysis, and the statistical investigation of the recorded data. 2. Since the fundamental natural period of Pohang New Harbor is almost the same as the second natural period of Young-il Bay, the seiche in Pohang New Harbor can be strongly amplified by the Oscillation in Young-il Bay. Therefore, the most strong seiche in Pohang New Harbor can occur when the long wave of about 25-minute period come into Young-il Bay.

• Journal of Korea Water Resources Association
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• v.44 no.3
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• pp.209-220
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• 2011

Input uncertainty is one of the major sources of uncertainty in hydrologic modeling. In this paper, first, three alternate rainfall inputs generated by different interpolation schemes were used to see the impact on a distributed watershed model. Later, the residuals of precipitation interpolations were tested as a source of ensemble streamflow generation in two river basins in the U.S. Using the Monte Carlo parameter search, the relationship between input and parameter uncertainty was also categorized to see sensitivity of the parameters to input differences. This analysis is useful not only to find the parameters that need more attention but also to transfer parameters calibrated for station measurement to the simulation using different inputs such as downscaled data from weather generator outputs. Input ensembles that preserves local statistical characteristics are used to generate streamflow ensembles hindcast, and showed that the ensemble sets are capturing the observed steamflow properly. This procedure is especially important to consider input uncertainties in the simulation of streamflow forecast.

• Land and Housing Review
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• v.5 no.4
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• pp.215-224
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• 2014

National street has become one of open space for enhancing environmental qualities of city and country. In the developed countries such as France, U.K. U.S.A are designed symbolic malls, squares and street which are represented the historicity, culture and symbolic place. For place identity, we analyzed the relationship between element and user satisfaction in Sejong Avenue, Gwangwhamun Square. Data were analyzed using statistical methods such as descriptive statistics, ANOVA and correlation. Results of this study are as follows, i) factor analysis is carried out to extract spatial components and satisfaction. The satisfaction concerning transportation access was the higher than other factors, ii) user satisfaction was strongly correlated on the spatial elements, iii) user showed high user perception to study site. Results of this study can identify representative street management plan based on landscape elements and user satisfaction.