• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.5
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• pp.574-583
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• 2021

Predicting shipping markets is an important issue. Such predictions form the basis for decisions on investment methods, fleet formation methods, freight rates, etc., which greatly affect the profits and survival of a company. To this end, in this study, we propose a shipping freight rate prediction model for container ships using gated recurrent units (GRUs) and long short-term memory structure. The target of our freight rate prediction is the China Container Freight Index (CCFI), and CCFI data from March 2003 to May 2020 were used for training. The CCFI after June 2020 was first predicted according to each model and then compared and analyzed with the actual CCFI. For the experimental model, a total of six models were designed according to the hyperparameter settings. Additionally, the ARIMA model was included in the experiment for performance comparison with the traditional analysis method. The optimal model was selected based on two evaluation methods. The first evaluation method selects the model with the smallest average value of the root mean square error (RMSE) obtained by repeating each model 10 times. The second method selects the model with the lowest RMSE in all experiments. The experimental results revealed not only the improved accuracy of the deep learning model compared to the traditional time series prediction model, ARIMA, but also the contribution in enhancing the risk management ability of freight fluctuations through deep learning models. On the contrary, in the event of sudden changes in freight owing to the effects of external factors such as the Covid-19 pandemic, the accuracy of the forecasting model reduced. The GRU1 model recorded the lowest RMSE (69.55, 49.35) in both evaluation methods, and it was selected as the optimal model.

• Journal of the Korea Convergence Society
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• v.9 no.11
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• pp.307-313
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• 2018

In this study, analyzed the effect of the introduction and operation of internal control system of a company on accounting information usefulness in a rapidly changing business environment. In order to conduct this study, we studied a comprehensive analysis on the usefulness of internal control and accounting information, and applied the research model to the purpose of this study. In this study, we analyzed the degree of the relationship between variables based on the discretionary accruals of the modified Jones model using the internal control evaluation index based on the components of the internal control system for China. In the empirical analysis, analyzed that the operation of internal control has a negative influence on discretionary accruals, which is a substitute for usability of accounting information. In addition, the risk management factors of the internal control system have a negative correlation with the usefulness of accounting information. The results of this study suggest that it is possible to present the positive function of internal control system to many firms where the introduction and operation of internal control is important, and to provide useful guidance in the study of the relationship between the operation of internal control and discretionary accruals for foreign company.

• Journal of the Korea Convergence Society
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• v.12 no.1
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• pp.99-104
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• 2021

In this paper, we propose health risk management using feature extraction and cluster analysis considering time flow. The proposed method proceeds in three steps. The first is the pre-processing and feature extraction step. It collects user's lifelog using a wearable device, removes incomplete data, errors, noise, and contradictory data, and processes missing values. Then, for feature extraction, important variables are selected through principal component analysis, and data similar to the relationship between the data are classified through correlation coefficient and covariance. In order to analyze the features extracted from the lifelog, dynamic clustering is performed through the K-means algorithm in consideration of the passage of time. The new data is clustered through the similarity distance measurement method based on the increment of the sum of squared errors. Next is to extract information about the cluster by considering the passage of time. Therefore, using the health decision-making system through feature clusters, risks able to managed through factors such as physical characteristics, lifestyle habits, disease status, health care event occurrence risk, and predictability. The performance evaluation compares the proposed method using Precision, Recall, and F-measure with the fuzzy and kernel-based clustering. As a result of the evaluation, the proposed method is excellently evaluated. Therefore, through the proposed method, it is possible to accurately predict and appropriately manage the user's potential health risk by using the similarity with the patient.

• Journal of the Korea Convergence Society
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• v.13 no.3
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• pp.337-343
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• 2022

The aim of this study was to evaluate anxiety, depression and stress in women with polycystic ovary syndrome(PCOS) and to investigate the risk factors related to psychological difficulties. Sixty women with PCOS were evaluated for level of psychological stress using Beck depression inventory(BDI) and Depression anxiety stress scale(DASS) questionnaire. Serum antimullerian hormone, total testosterone, lutenizing hormone, follicle stimulating hormone, estradiol, lipid profile and 75g oral glucose tolerance test were measured. Thirty healthy women served as the control. Fifty two women with PCOS and 29 healthy women completed a questionnaire. Women with depression who scored >13 by BDI and >10 by DASS were 38.5 %, women with anxiety who scored >8 by DASS were 23.1 %, and women with stress who scored >15 by DASS were 30.8 %, which were significantly higher than control. In PCOS women, total testosterone, LH and AMH were significantly correlated with depression and stress. Weight, body mass index and waist-hip ratio were also significantly correlated with depression. In women diagnosed as diabetes and hyperlipidemia, depression and stress were significantly prevalent. Women with PCOS seemed to be more vulnerable to depression, anxiety and stress. Early diagnosis and management should be considered.

• Journal of Chest Surgery
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• v.40 no.2 s.271
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• pp.114-121
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• 2007

Background: Apoptosis plays a crucial role in carcinogenesis, as well as in development and tissue homeostasis. Terminal deoxyribonucleotidyl transferase mediated neck end labelling (TUNEL) and in situ nick end labelling (ISEL) have been used to investigate the apoptosis in tissues. Since the introduction of the M30 monoclonal antibody to overcome drawbacks of TUNEL and ISEL, the apoptosis in various tumors, with the exception of pulmonary carcinomas, has been studied. In this study, attempts were made to examine the correlation of apoptosis in non-small cell carcinomas, using both M30 and the expression of p53 protein, with the clinicopathological factors. Material and Method: Forty five patients with surgically resected non-small cell carcinomas were included. Immunohistochemical staining with M30 and p53 monoclonal antibody were peformed, and their expressions compared with the clinicopathological features. The overall survival time and recurrence-free survival time were calculated, and the factors influencing the survival time analyzed using a univariate analysis. The effects of the expression stati of M30 and p53 on the risks of cancer related to both death and recurrence were evaluated using a multivariate analysis. Result: The p53 positive group had many more M30 positive cells than the p53 negative group (p53 positive group; $61.7{\pm}26.8$ cells vs. p53 negative group; $45.6{\pm}29.6$ cells, p=0.005) and significantly more p53 positive patients showing at least 10 positive cells (apoptotic index, $Al{\ge}1$) on M30 staining (p53 positive group; 52.4% (11/21) vs. p53 negative group 16,7% (4/24), p=0.025). In the univariate analysis, the survival times in relation to smoking (pack-year), performance status (PS) and Al showed significant differences. The multivariate analysis demonstrated the relative risk (R.R) of cancer death increased almost 7.5-fold (R.R 7.482; 95% Cl $1.886{\sim}29.678$; p=0.004) and the risk of recurrence almost 3,8-fold (R.R 3.795; 95% Cl: $1.184{\sim}12.158$; p=0.025) in the high Al (${\ge}1$) compared to the low Al (<1) group. There was no prognostic effect of p53 expression on the survival time or risk of cancer death and recurrence. Conclusion: In non-small cell lung carcinomas, M30 immunohistochemistry was an excellent method for analyzing apoptosis; the high apoptotic index could be an adverse prognostic predictive factor.

• Journal of Nutrition and Health
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• v.52 no.5
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• pp.449-464
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• 2019

Purpose: North Koreans could be at higher risk for their bone health because of previous periods of severe famine and the continuing low availability of food. This study determined the bone mineral density (BMD) status and its relationship with dietary behaviors and nutrient intake of North Korean refugees (NKR) in South Korea (SK). Methods: This cross-sectional study analyzed 110 female NKR from a NORNS cohort of a non-probability sample of adult NKR in Seoul. BMD examined by DEXA was used to divide participants into the normal group (NG) and the non-normal group (NNG) according to the WHO guideline. A self-administered questionnaire included questions on age, the socioeconomic situation in North Korea (NK) and SK, the food security in NK and SK, and the health behaviors, dietary behaviors, and food frequency questionnaire administered in SK. A one-day 24-hr recall was conducted and the results were analyzed by using CanPro. SPSS was used to analyze whether BMD and related dietary behaviors and nutrient intakes differed according to the groups. Results: NG (62.7%) was significantly younger and had a lower abdominal obesity score than NNG (p < 0.001). While 14.5% of NG reported experiencing menopause, all of NNG reported experiencing menopause. The NG more frequently consumed the dairy group of foods (9.6 times a week) than did the NNG (4.8 times a week) after the statistics were adjusted for age (p < 0.007). The NG consumed significantly more animal protein and animal calcium than did the NNG (p = 0.01, p = 0.009, respectively). Calcium intake was low with 49.3% of NG, and 78.0% of the NNG reported consuming calcium lower than the estimated average requirement. Only calcium showed an index of nutrient quality lower than one in both groups. Conclusion: These results showed that NKR women and possibly all North Korean women are at high risk for bone health and they consumed low levels of bone-related nutrients, and this should be considered for the nutrition policy for NKR and North Korea.

• Clinical and Experimental Pediatrics
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• v.51 no.1
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• pp.42-46
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• 2008

Purpose : Apolipoprotein E (Apo E) plays a major role in lipoprotein metabolism and lipid transport. Many investigators have described that Apo E polymorphisms is one of the most important genetic determinants for cardiovascular disease. The purpose of this study was to evaluate the association between Apo E polymorphisms and serum lipid profiles in obese adolescent. Methods : We measured the serum concentrations of glucose, apolipoprotein (Apo) A1, Apo B, total cholesterol (TC), triglyceride (TG), HDL and LDL-cholesterol after overnight fasting in obese adolescent. Apo E polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results : 86 obese adolescents participated in this study. The body mass index (BMI) of participants were excess of 95 percentile by age and sex. Male to female ratio was 1.7 and mean age of study group was $16.2{\pm}1.8\;years$. Mean BMI was $27.4{\pm}2.5kg/m^2$. The frequency of ${\varepsilon}2$, ${\varepsilon}3$ and ${\varepsilon}4$ allele were 8.1%, 87.2% and 4.7% respectively. Study populations were classified into the following three genotypes 1) Apo E2 group (n=13, 15.1%) carrying either the ${\varepsilon}2/{\varepsilon}2$ or ${\varepsilon}2/{\varepsilon}3$ 2) Apo E3 group (n=65, 75.6%) carrying the most frequent ${\varepsilon}3/{\varepsilon}3$ 3) Apo E4 group (n=8, 9.3%) carrying either the ${\varepsilon}3/{\varepsilon}4$ or ${\varepsilon}4/{\varepsilon}4$. No differences were found among Apo E genotypes concerning age, sex, weight, height and BMI. Apo B and LDL-cholesterol concentrations were significantly higher in the Apo E4 group (P<0.05). No association were found between Apo E genotypes and glucose, Apo A1, TC, TG and HDL. Conclusions : We confirmed that serum concentrations Apo B and LDL-cholesterol were influenced by Apo E genotypes. Apo E polymorphisms seems to influence some alteration of lipid metabolism associated with obesity in adolescent.

• Journal of Intelligence and Information Systems
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• v.23 no.2
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• pp.107-122
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• 2017

Volatility in the stock market returns is a measure of investment risk. It plays a central role in portfolio optimization, asset pricing and risk management as well as most theoretical financial models. Engle(1982) presented a pioneering paper on the stock market volatility that explains the time-variant characteristics embedded in the stock market return volatility. His model, Autoregressive Conditional Heteroscedasticity (ARCH), was generalized by Bollerslev(1986) as GARCH models. Empirical studies have shown that GARCH models describes well the fat-tailed return distributions and volatility clustering phenomenon appearing in stock prices. The parameters of the GARCH models are generally estimated by the maximum likelihood estimation (MLE) based on the standard normal density. But, since 1987 Black Monday, the stock market prices have become very complex and shown a lot of noisy terms. Recent studies start to apply artificial intelligent approach in estimating the GARCH parameters as a substitute for the MLE. The paper presents SVR-based GARCH process and compares with MLE-based GARCH process to estimate the parameters of GARCH models which are known to well forecast stock market volatility. Kernel functions used in SVR estimation process are linear, polynomial and radial. We analyzed the suggested models with KOSPI 200 Index. This index is constituted by 200 blue chip stocks listed in the Korea Exchange. We sampled KOSPI 200 daily closing values from 2010 to 2015. Sample observations are 1487 days. We used 1187 days to train the suggested GARCH models and the remaining 300 days were used as testing data. First, symmetric and asymmetric GARCH models are estimated by MLE. We forecasted KOSPI 200 Index return volatility and the statistical metric MSE shows better results for the asymmetric GARCH models such as E-GARCH or GJR-GARCH. This is consistent with the documented non-normal return distribution characteristics with fat-tail and leptokurtosis. Compared with MLE estimation process, SVR-based GARCH models outperform the MLE methodology in KOSPI 200 Index return volatility forecasting. Polynomial kernel function shows exceptionally lower forecasting accuracy. We suggested Intelligent Volatility Trading System (IVTS) that utilizes the forecasted volatility results. IVTS entry rules are as follows. If forecasted tomorrow volatility will increase then buy volatility today. If forecasted tomorrow volatility will decrease then sell volatility today. If forecasted volatility direction does not change we hold the existing buy or sell positions. IVTS is assumed to buy and sell historical volatility values. This is somewhat unreal because we cannot trade historical volatility values themselves. But our simulation results are meaningful since the Korea Exchange introduced volatility futures contract that traders can trade since November 2014. The trading systems with SVR-based GARCH models show higher returns than MLE-based GARCH in the testing period. And trading profitable percentages of MLE-based GARCH IVTS models range from 47.5% to 50.0%, trading profitable percentages of SVR-based GARCH IVTS models range from 51.8% to 59.7%. MLE-based symmetric S-GARCH shows +150.2% return and SVR-based symmetric S-GARCH shows +526.4% return. MLE-based asymmetric E-GARCH shows -72% return and SVR-based asymmetric E-GARCH shows +245.6% return. MLE-based asymmetric GJR-GARCH shows -98.7% return and SVR-based asymmetric GJR-GARCH shows +126.3% return. Linear kernel function shows higher trading returns than radial kernel function. Best performance of SVR-based IVTS is +526.4% and that of MLE-based IVTS is +150.2%. SVR-based GARCH IVTS shows higher trading frequency. This study has some limitations. Our models are solely based on SVR. Other artificial intelligence models are needed to search for better performance. We do not consider costs incurred in the trading process including brokerage commissions and slippage costs. IVTS trading performance is unreal since we use historical volatility values as trading objects. The exact forecasting of stock market volatility is essential in the real trading as well as asset pricing models. Further studies on other machine learning-based GARCH models can give better information for the stock market investors.

• The Journal of the Korea Contents Association
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• v.18 no.5
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• pp.432-445
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• 2018

For health care professionals(HCPs) who have relatively higher possibility of exposing tuberculosis(Tb), it is important for them to equip with proper levels of knowledge and prevention activities. In terms of establishment of Tb education model for junior HCPs, therefore, literature review was done alongside 129 junior HCPs and 14 HCPs were asked to answer questionnaires and telephone survey. The results are follows.; Firstly, six educational themes such as epidermiology of Tb, Tb transmission and patho-physiology, test and diagnosis, latent Tb, Tb treatment, and Tb prevention were identified, based on the literature review. Secondly, the junior HCPs showed lower levels of knowledge regarding epidermiology, transmission and patho-physiology and latent Tb, compared to the other themes. When education courses are planned, longer period of time should be given to the lower level of knowledge areas. Thirdly, the HCPs emphasized that definition and type of Tb should be well integrated into the education in particular epidermiology education. They also responded that hospital infection and infection cycle of Tb need to be addressed during educational session about transmission and patho-physiology. in addition, they said that specific and detailed contents about diagnosis and group examination should be carefully delivered during the education, along with diagnosis, test and application of personal protective devices during education of latent Tb. They also answered that patient education and adverse effect of Tb medication should be taught during Tb treatment session, as well as self activities of health promotion for junior HCPs and systematic TB education as key way of Tb prevention. As the findings were from limited numbers of respondents and contained the sampling bias, the result has to be carefully interpretated prior to generalization. Therefore, further survey with larger study population is required in terms of development of Tb education model.

• Tuberculosis and Respiratory Diseases
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• v.63 no.3
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• pp.251-260
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• 2007

Purpose: An imbalance of cell proliferation and cell apoptosis is an important mechanism in carcinogenesis. Capase 3, survivin and p53 have been identified as important members of the apoptotic related proteins. This study evaluated the proliferating cell nuclear antigen(PCNA), apoptosis, apoptotic related protein such as capase 3, survivin and p53 using urethane-induced mouse lung carcinogenesis, which provides reproducible steps from hyperplasia to adenocarcinoma. Methods: Urethane was administered to the ICR mice through an intra-peritoneal injection, The mice were sacrificed at 5, 15, and 25 weeks after urethane intervention. The sequential morphological changes and immunohistochemical expression of PCNA, apoptosis, capase 3, survivin, and p53 were examined during mouse lung carcinogenesis. Results: During carcinogenesis, the sequential histological changes were observed from hyperplasia of type II pneumocytes, to anadenoma, and ultimately to an overt adenocarcinoma. The PCNA Labeling index (LI) was 9.6% in hyperplasia, 23.2% in adenoma, and 55.7% in adenocarcinoma, respectively. The apoptotic LI was 0.24% in hyperplasia, 1.25% in adenoma, and 5.27% in adenocarcinoma. A good correlation was observed between the PCNA LI and apoptotic LI. The expression of caspase 3 was remarkable- i.e., 46.7% in adenocarcinoma, in contrast to 15% in hyperplasia and 16% in adenoma. Survivin was detected weakly in the alveolar hyperplasia and showed an increasing expressional pattern in adenoma and adenocarcinoma. p53 expression was detected only in the adenocarcinoma lesions with an expression rate of 13.3%. The level of caspase 3 expression correlated with the increase in the apoptotic index. The positive expression of caspase 3 was associated with an increased apoptotic index. Conclusions: These results suggest that the PCNA LI and apoptotic LI might be useful markers for evaluating the risk of a malignant transformation. In addition, caspase, survivin and p53 might play a role in the early and late steges of urethane-induced mouse lung carcinogenesis.