• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.539-545
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• 2018

In recent years, research on shipping market forecasting with the employment of non-linear AI models has attracted significant interest. In previous studies, input variables were selected with reference to past papers or by relying on the intuitions of the researchers. This paper attempts to address this issue by applying the stepwise regression model and the random forest model to the Cape-size bulk carrier market. The Cape market was selected due to the simplicity of its supply and demand structure. The preliminary selection of the determinants resulted in 16 variables. In the next stage, 8 features from the stepwise regression model and 10 features from the random forest model were screened as important determinants. The chosen variables were used to test both models. Based on the analysis of the models, it was observed that the random forest model outperforms the stepwise regression model. This research is significant because it provides a scientific basis which can be used to find the determinants in shipping market forecasting, and utilize a machine-learning model in the process. The results of this research can be used to enhance the decisions of chartering desks by offering a guideline for market analysis.

• Pediatric Infection and Vaccine
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• v.11 no.1
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• pp.73-80
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• 2004

Purpose : The serial clinical findings, biochemical results, and serological hepatitis B virus(HBV) markers in Korean children with chronic HBV infection were analyzed to determine the relationships among these factors. Methods : Ninety children have been chosen from those who have visited to the Department of Pediatrics at St. Vincent's Hospital in The Catholic University of Korea from July 1st, 1995 to June 30th, 2000. The sample patients were followed up for over six months. HBV markers and liver function tests were all performed. Results : All children were asymptomatic at presentation. Eighty-three percent of the children had a history of chronic HBV infection in their families. Eighty-one percent were HBeAg positive, 16% were anti-HBe positive, while 3% were all HBeAg and anti-HBe negative. The prevalence of HBeAg among three age groups : 0~5; 6~10; and 11~15 year-old was 90%, 96% and 61% respectively. The prevalence of HBeAg in less than 10 year-old group was significantly higher than 11~15 year-old group(P=0.001). Serum ALT levels were within 40 IU/L in 64% children, 41~80 IU/L in 17%, 81~200 IU/L in 10%, and beyond 201 IU/L in 9%. The percentage of abnormality of ALT levels in HBeAg positive patients was significantly higher than that of HBeAg negative(P=0.036). Eleven of the 73 HBeAg positive children lost their HBeAg and seroconverted to anti-HBe. In these cases, all had transient elevations in ALT levels before HBeAg seroconversions. The annual rates of spontaneous seroconversion of HBeAg and HBsAg were 9.7% and 0.6%, respectively. Conclusion : Recognition of the dynamics of these changes in viral markers and biochemical findings is needed in the selection and evaluation of therapeutic regimens, establishment of treatment, and calling for controlled trials with adequate follow-up. The hepatitis B carrier state may be asymptomatic in children however, continued surveillance of carriers is important to determine the individual adverse prognostic factors of chronic HBV infections.

• Journal of the Korean Applied Science and Technology
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• v.40 no.1
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• pp.13-23
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• 2023

This study is an experimental study on the single group pre-post test design for the effects of the aroma inhalation method with roll-on on stress, pain, depression and blood pressure of the elderly. 33 elderly people who met the selection criteria participated among the elderly using the senior citizen clubs located in S city, Gyeonggi-do. The data collection period was from November 14, 2022 to December 19, 2022. A questionnaire consisting of stress, pain, depression, and blood pressure was measured before and after the aroma roll-on inhalation intervention. The components of aroma essential oil included Marjoram, Geranium, Peppermint and Orange sweet that were diluted in Jojoba oil which was the carrier oil. The aroma inhalation method with roll-on was carried out 3 times day for 4 weeks. In the result of this study, the aroma inhalation method with roll-on were statistically significant differences in stress(t=2.63, p=.013), pain(t=2.46, p=.019), and systolic blood pressure(t=3.01, p=.005) of the participants. Therefore, aroma roll-on therapy is expected to be available as a useful nursing intervention method for reducing stress, relieving pain, and managing blood pressure in the elderly using the senior citizen clubs.