• Nutrition Research and Practice
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• v.10 no.4
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• pp.448-455
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• 2016

BACKGROUND/OBJECTIVES: A growing body of research has indicated that night eating could be associated with poor diet quality and negative health outcomes. This study examined the nutritional aspects of night eating, its related factors, and the association between night eating and body weight among Korean adolescents. SUBJECTS/METHODS: This study analysed the data from a one day 24-hour dietary recall as well as a demographic survey of 1,738 Korean adolescents aged 12 to 18-years-old obtained from the 2010-2012 Korea National Health and Nutrition Examination Survey. 'Night eating' was defined as consuming 25% or more of one's daily energy intake between 21:00 and 06:00. Subjects complying with the preceding condition were classified as 'night eaters', whereas the rest were considered 'non-night eaters'. Logistic regression analysis examined factors related to night eating. Multiple linear regression analyses were used to examine the relationship between night eating and BMI z-scores, whereas multinomial logistic regression analysis was used to examine the relationship between night eating and weight status. RESULTS: About 21% of Korean adolescents appeared to be night eaters. Night eaters showed increased breakfast skipping (P = 0.001), higher energy intake from snacks (P < 0.001), greater proportion of energy intake from fat (P = 0.029), and lower Dietary Diversity Scores (P = 0.008) than non-night eaters. Male adolescents presented 1.9 times higher odds of being night eaters than females. Adolescents whose both parents were night eaters were 4.4 times as likely to be night eaters as those whose neither parents were. Female adolescents showed a significant relationship between night eating and BMI z-scores (${\beta}=0.28$, P = 0.004). However, night eating did not increase odds of being overweight or obese in adolescents. CONCLUSIONS: Night eating in Korean adolescents was related to undesirable dietary behaviours and low diet quality in general as well as higher BMI z-scores in females. Male gender and parental night eating appeared to be the factors that significantly increased odds of night eating. These results suggest that night eating should be considered when designing nutrition education or intervention programs targeting adolescents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.438-446
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• 2019

This study examined the effects of non - personality behavior of supervisors on the job exhaustion and organizational effectiveness of nurses. A survey in the form of a questionnaire was completed by 250 nurses working at three general hospitals located in Seoul and Gyeonggi from September 20 to October 31, 2014. The collected data were analyzed by frequency analysis, factor analysis, correlation, and linear regression analysis using the SPSS program. The results of the analysis were as follows. First, the effects of the non-personality behavior of supervisors on the job exhaustion of nurses were statistically significant. Second, the effects of non-personality behavior of supervisors on the organizational effectiveness of nurses were statistically significant in job satisfaction, organizational commitment, and organizational citizenship behavior. Third, the effects of job exhaustion on organizational effectiveness of nurses was statistically significant for job satisfaction, job exhaustion, and organizational citizenship behavior. Because the non-personality behavior of a supervisor can have a negative effect on the exhaustion of a nurse's job and the organizational effectiveness, there should be a wide range of human resources and effective task allocations in a hospital to reduce job burnout and increase job satisfaction. In addition, it is necessary for the boss to develop desirable leadership education, appropriate modeling, and reduce their negative influence in the workplace.

• Journal of the Korean Geotechnical Society
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• v.32 no.7
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• pp.5-14
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• 2016

The use of geothermal energy has increased for economically and environmentally friendly utilization, and a geothermal heat pump (GSHP) system for space heating and cooling is being used widely. As ground thermal properties such as ground thermal conductivity and ground thermal diffusivity are substantial parameters in the design of geothermal heat pump system, ground thermal conductivity should be obtained from in-situ thermal response test (TRT). This paper presents an experimental study of ground thermal properties of U and 2U type ground heat exchangers (GHEs) measured by TRTs. The U and 2U type GHEs were installed in a partially saturated dredged soil deposit, and TRTs were conducted for 48 hours. A method to derive the thermal diffusivity as well as thermal conductivity was proposed from a non-linear regression analysis. In addition, remolded soil samples from different layers were collected from the field, and soil specimens were reconstructed according to the field ground condition. Then equivalent ground thermal conductivity and ground thermal diffusivity were calculated from the lab test results and they were compared with the in-situ TRT results.

• Korean Journal of Weed Science
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• v.30 no.1
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• pp.50-57
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• 2010

This experiment was conducted to investigate seedling emergence of Humulus japonicus in Seoul and Suwon and to predict its seedling emergence in various locations in Korea. Non-linear regression analysis to fit Gompertz model to accumulated seedling emergence of H. japonicus was performed to describe its seedling emergence. Parameter estimates from the non-linear regression and estimated effective accumulated temperature required for its seedling emergence were further used to predict seedling emergence of H. japonicus in 8 major geographical regions of Korea. Seedling emergence of H. japonicus versus effective accumulated temperature was well described by Gompertz model in both Seoul and Suwon. Effective accumulated temperatures required for the first seedling emergence and 50% of the maximum seedling emergence were estimated to be $56.7^{\circ}C$ and $76.3^{\circ}C$, respectively. Therefore, the dates for the first seedling emergence of H. japonicus were predicted to be 21 and 30 March in Daegu and Daejeon, while 4 and 6 April in Suwon and Chuncheon, respectively. The dates reaching 50% of maximum seedling emergence were also predicted to be 25 March in Daegu, while 3, 8 and 9 April in Daejeon, Suwon and Chuncheon, respectively.

• Journal of Soil and Groundwater Environment
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• v.11 no.2
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• pp.56-67
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• 2006

Trends of variation in groundwater levels, electrical conductivities and water temperatures obtained from the national groundwater monitoring stations (95 shallow and 169 deep wells) of Korea were evaluated. For the analysis, both parametric (linear regression) and non-parametric (Mann-Kendall test, Sen's test) methods were adopted. Results of linear regression analysis indicated that about 50% of the monitoring wells showed increasing trends of groundwater levels, electrical conductivities, and water temperatures and the others showed decreasing trends. However, the non-parametric analyses with monthly median values revealed that $14.8{\sim}20.0%$ of water levels were decreased, $24.2{\sim}36.9%$ of electrical conductivities were increased, and $27.4{\sim}32.5%$ of water temperatures were increased at a confidence level of 99%. Highly proportions of increasing or decreasing trends were unexpected and they resulted from the relatively short term of data collection (maximum 6 years). Meanwhile, the investigation of groundwater around the national groundwater monitoring stations showed that the decreasing or increasing trends of water levels, electrical conductivities, themselves, didn't indicate directly groundwater hazards such as groundwater depletion or groundwater contamination. Both the values and variation rates (slopes) of water level, electrical conductivity and temperature in the longer period are considered simultaneously. This study is the first comprehensive work in analyzing trends of groundwater data obtained from the national groundwater monitoring stations. Based on this study, the periodical and regular analysis of groundwater data is essentially required to grasp the overall variational trend of groundwater resources in the country.

• 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.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.206-216
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• 2020

As the number of aging railway bridges in Korea increases, maintenance costs due to aging are increasing and continuous management is becoming more important. However, while the number of old facilities to be managed increases, there is a shortage of professional personnel capable of inspecting and diagnosing these old facilities. To solve these problems, this study presents an improved model that can detect Local damage to structures using machine learning techniques of AI technology. To construct a damage detection machine learning model, an analysis model of the bridge was set by referring to the design drawing of a non-ballasted plate-girder railroad bridge. Static strain data according to the damage scenario was extracted with the analysis model, and the Local damage index based on the reliability of the bridge was presented using statistical techniques. Damage was performed in a three-step process of identifying the damage existence, the damage location, and the damage severity. In the estimation of the damage severity, a linear regression model was additionally considered to detect random damage. Finally, the random damage location was estimated and verified using a machine learning-based damage detection classification learning model and a regression model.

• Nutrition Research and Practice
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• v.5 no.5
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• pp.450-454
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• 2011

The beneficial effects of total parenteral nutrition (TPN) in improving the nutritional status of malnourished patients during hospital stays have been well established. However, recent randomized trials and meta-analyses have reported an increased rate of TPN-associated complications and mortality in critically ill patients. The increased risk of complications during TPN therapy has been linked to the development of hyperglycemia, especially during the first few days of TPN therapy. This retrospective study was conducted to determine whether the amount of dextrose from TPN in the 1st week in the intensive care unit (ICU) was related to the development of hyperglycemia and the clinical outcome. We included 88 non-diabetic critically ill patients who stayed in the medical ICU for more than two days. The subjects were 65 ${\pm}$ 16 years old, and the mean APACHE (Acute Physiology and Chronic Health Evaluation) II score upon admission was 20.9${\pm}$7.1. The subjects received 2.3${\pm}$1.4 g/kg/day of dextrose intravenously. We divided the subjects into two groups according to the mean blood glucose (BG) level during the 1st week of ICU stay: <140 mg/dl vs ${\geq}$ 140 mg/dl. Baseline BG and the amount of dextrose delivered via TPN were significantly higher in the hyperglycemia group than those in the normoglycemia group. Mortality was higher in the hyperglycemia group than in the normoglycemia group (42.4% vs 12.8%, P=0.008). The amount of dextrose from TPN was the only significant variable in the multiple linear regression analysis, which included age, APACHE II score, baseline blood glucose concentration and dextrose delivery via TPN as independent variables. We concluded that the amount of dextrose delivered via TPN might be associated with the development of hyperglycemia in critically ill patients without a history of diabetes mellitus. The amount of dextrose in TPN should be decided and adapted carefully to maintain blood glucose within the target range.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2002.11a
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• pp.59-62
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• 2002

Wavelength selection and prediction algorithm for determining hematocrit are investigated. A model based on the difference in optical density induced by the pulsation of heart beat is developed by taking approximation of Twersky's theory on the assumption that the variation of blood vessel size is small during arterial pulsing[1]. A device is constructed with a five-wavelength LED array as light source. The selected wavelengths are two isobestic points and three in compensation for tissue scattering. Data are collected from 549 out-patients who are randomly grouped as calibration and prediction sets. The range of percent hematocrit was 19.3∼51.8. The ratio of the variations of optical density between systole and diastole at two different wavelengths is used as a variable. We selected several such variables that show high reproducibility among all variables. Multiple linear regression analysis is made. The relative percent error is 8% and the standard deviation is 3.67 for the calibration set. The relative % error and standard deviation of the prediction set are 8.2% and 3.69 respectively. We successfully demonstrate the possibility of non-invasive hematocrit measurement, particularly, using the wavelengths below 1000nm.

• Journal of Chest Surgery
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• v.55 no.3
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• pp.214-224
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• 2022

Background: Studies of the prognostic role of circulating tumor cells (CTCs) in early-stage non-small cell lung cancer (NSCLC) are still limited. This study investigated the prognostic power of CTCs from the pulmonary vein (PV), peripheral blood (PB), and bone marrow (BM) for postoperative recurrence in patients who underwent curative resection for NSCLC. Methods: Forty patients who underwent curative resection for NSCLC were enrolled. Before resection, 10-mL samples were obtained of PB from the radial artery, blood from the PV of the lobe containing the tumor, and BM aspirates from the rib. A microfabricated filter was used for CTC enrichment, and immunofluorescence staining was used to identify CTCs. Results: The pathologic stage was stage I in 8 patients (20%), II in 15 (38%), III in 14 (35%), and IV in 3 (8%). The median number of PB-, PV-, and BM-CTCs was 4, 4, and 5, respectively. A time-dependent receiver operating characteristic curve analysis showed that PB-CTCs had excellent predictive value for recurrence-free survival (RFS), with the highest area under the curve at each time point (first, second, and third quartiles of RFS). In a multivariate Cox proportional hazard regression model, PB-CTCs were an independent risk factor for recurrence (hazard ratio, 10.580; 95% confidence interval, 1.637-68.388; p<0.013). Conclusion: The presence of ≥4 PB-CTCs was an independent poor prognostic factor for RFS, and PV-CTCs and PB-CTCs had a positive linear correlation in patients with recurrence.