• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.1
• /
• pp.25-36
• /
• 2016

Heavy metals in the stream sediments around Shihwa Lake were studied not only to investigate the characteristics of spacio-temporal distribution but also to assess the pollution degree and ecological risk using various pollution indices. Among metals, Zn had the highest values (1,311 mg/kg) and Hg showed the lowest value (0.261 mg/kg). The order of mean concentrations (mg/kg) of metals was Zn>Cu>Pb>Cr>Ni>Co>As>Cd>Hg in stream sediments around Shihwa Lake. Metal concentrations showed different pollution pattern with industrial region, indicating that these metals originated from different sources and industrial region had higher metal concentration than rural/urban regions. The results of geoaccumulation index (Igeo) showed that the stream sediments were significantly polluted with Cd, Cu, Zn and Pb, indicating moderately to highly polluted by these metals. According to PLI consideration, industrial region was more seriously polluted by metals whereas an rural/urban region was not polluted. About 85% of sampling site for Cr, Ni, Cu, Zn and Pb from industrial regions were exceeded the PEL values. The mPELQ and SQI values derived from PEL of industrial region were classified as 'highly toxic' and 'very poor' and metal pollution level tend to be worse in wet season. This indicates that the industrial activities and stromwater runoff represents an important sources of heavy metals around Shihwa Lake.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.9
• /
• pp.3997-4002
• /
• 2015

Background: Systemic inflammatory response was shown to play an important role in development and progression of many cancer types and different inflammation-based indices were used for determining prognosis. We aimed to investigate the prognostic effects of neutrophil to lymphocyte ratio (NLR) and prognostic nutritional index (PNI) in patients with non-small cell lung cancer (NSCLC). Materials and Methods: NSCLC patients diagnosed in our institution were retrospectively reviewed. Demographic and clinicopathologic characteristics were recorded. NLR and PNI was calculated before the application of any treatment. Results: A total of 138 patients were included in the study. Patients were divided into two groups according to NLR (<3.24 or ${\geq}3.24$) and PNI (<49.5 or ${\geq}49.5$). While median overall survival was 37.0 (95% CI 17.5-56.5) months in the group with low NLR, it was calculated as 10.0 (95%CI 5.0-15.0) months in the group with high NLR (p<0.0001). While median overall survival was 7.0 (95%CI 3.5-10.5) months in the group with low PNI, it was calculated as 33.0 (95% CI 15.5-50.4) months in the group with high PNI (p<0.0001). Stage, NLR and PNI levels were evaluated as independent risk factors for overall survival for all patients in multivariate analysis (p<0.0001, p=0.04 and p<0.001, respectively). Conclusions: NLR (${\geq}3.24$) and PNI (<49.5) at diagnosis is an independent marker of poor outcome in patients with NSCLC. NLR and PNI is an easily measured, reproducible prognostic tests that could be considered in NSCLC patients.

• Korean Journal of Construction Engineering and Management
• /
• v.11 no.1
• /
• pp.59-69
• /
• 2010

Although international construction market gradually takes a important position among the export industries, the previous studies about international construction entry strategy have just focussed on trend investigation or suggestion for revitalization. Moreover, in order to prepare the market uncertainty such as world financial crisis and to plan the long term strategy, specific strategy studies based on corporate level are required. Therefore, this study estimates the nine strategic index and four financial index of 31 companies that performed 1920 international projects from 1993 to 2007 and evaluate the performance as three periods by multi-regression analysis. Also, this study analyze dynamic correlation between these index and the performance considering times. this study verifies that market diversification, product diversification, localization and decrease of debt to asset ratio make a good effect on the international order as long term strategy and shows that collaborated entry with domestic corporations, alliance entry with host country's company, alliance entry with third country's company, portion of labor cost and portion of management expense differently make a influence on the performance as times. these results will be helpful for the construction companies to plan the international entry strategy reasonably and specifically.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.23 no.6
• /
• pp.699-709
• /
• 2017

We measured the grain size, total organic carbon (TOC), total nitrogen (TN), and heavy metals (As, Cd, Cr, Cu, Fe, Hg, Mn, Pb, and Zn) in order to understand the spatial distribution and pollution level of organic matter and metals in surface sediment around Goseong Bay, a shellfish farming area, Korea. The surface sediments were composed of finer sediments such as mud and clay. The concentration of TOC, TN, and heavy metals were much higher in the innermost bay than in the mouth and outside of bay. The spatial distribution of organic matter and heavy metals and C/N ratio (5-10) in sediment showed that the organic matter and heavy metals in sediment of the study region were significantly influenced by oceanic origin organic matter and anthropogenic sources, respectively. Based on the results of four assessment techniques (sediment quality guideline, geoaccumulation index, pollution load index, ecological risk index), the sediments around the Goseong Bay were a little polluted for heavy metals and the high metal concentrations in the northern region of bay could adverse impact on benthic organisms in sediment. Thus, the systematic management plan for the improvement of water and sediment environment and the concentrated monitoring of pollutants for sustainable aquaculture and seafood safety around Goseong Bay are necessary in the future.

• Journal of Korea Water Resources Association
• /
• v.56 no.12
• /
• pp.883-893
• /
• 2023

While South Korea's dependence on imported grains is very high, droughts impacts from exporting countries have been overlooked. Using the Evaporative Stress Index (ESI), this study globally analyzed frequency, extent, and long-term trends of agricultural droughts and their relation to natural oscillations and global crop prices. Results showed that global-scale correlations were found between ESI and soil moisture anomalies, and they were particularly strong in crop cultivation areas. The high correlations in crop cultivation areas imply a strong land-atmosphere coupling, which can lead to relatively large yield losses with a minor soil moisture deficits. ESI showed a clear decreasing trend in crop cultivation areas from 1991 to 2022, and this trend may continue due to global warming. The sharp increases in the grain prices in 2012 and 2022 were likely related to increased drought areas in major grain-exporting countries, and they seemed to elevate South Korea's producer price index. This study suggests the need for drought risk management for grain-exporting countries to reduce socioeconomic impacts in South Korea.

• Journal of Nutrition and Health
• /
• v.47 no.4
• /
• pp.258-267
• /
• 2014

Purpose: The current study was designed to investigate the relationship of dietary calcium and riboflavin and their main dietary source (milk and dairy products) with the risk of periodontitis using data from 2007 to 2010 Korea National Health and Nutrition Examination Surveys. Methods: A total of 1,690 adults aged ${\geq}40$ years were included. We used results of dental examination regarding all sextant information on probing depth of at least two index teeth, nutritional assessment by a single 24-hour dietary recall, and demographic and medical information. The periodontitis group was defined as those who had 3-4 points, and the normal group was defined as those who had 0 points of Community Periodontal Index at all locations of six examination sites using a probe. Results: Using multiple logistic regression analysis, after adjustment for age, body mass index, energy intake, income, smoking, and alcohol drinking, we found an inverse relationship between consumption of dairy products and risk for periodontitis (OR: 0.465, 95% CI: 0.224-0.964) and between dietary riboflavin intake more than the estimated average requirements and risk for periodontitis (OR: 0.535, 95% CI: 0.300-0.954) in males. Conclusion: Adequate intake of milk dairy products and riboflavin may be recommended for prevention of periodontitis in the Korean male population.

• Journal of Food Hygiene and Safety
• /
• v.39 no.4
• /
• pp.322-334
• /
• 2024

This study investigated the content of heavy metals (Pb, Cd, As, and Hg) and SO₂ and conducted a risk assessment of 1,340 samples of 60 herbs used for food and medicine in Seoul between 2019 and 2023. The analysis was performed using inductively coupled plasma mass spectrometry (ICP-MS), a mercury analyzer, and the Monier-Williams method. The mean values and ranges of the heavy metals were as follows: Pb, 0.327 mg/kg (not detectable [ND]-36.933); Cd, 0.083 mg/kg (ND-1.700); As, 0.075 mg/kg (ND-2.200); and Hg, 0.004 mg/kg (ND-0.047). Pb exceeded the permissible limit of 36.933 mg/kg in one sample of Poria Sclerotium. Cd exceeded the permissible limit of 1.700 mg/kg and 0.650 mg/kg in the two samples of Chrysanthemi Zawadskii Herba. The mean and range of SO₂ was 0.75 mg/kg (ND-192.00), with two samples of Gastrodiae Rhizoma exceeding the permissible limit at 192.00 mg/kg and 42.00 mg/kg. Pb was highest in the perithecium (1.377 mg/kg), followed by Cd in the cortex (0.156 mg/kg) and caulis (0.144 mg/kg), As in leaves (0.149 mg/kg), and Hg in the herba (0.009 mg/kg) and leaves (0.009 mg/kg). SO₂ was the highest in the rhizomes (4.12 mg/kg). The Pb, Cd, and Hg levels did not differ significantly between the domestic, Chinese, and imported products; however, As and SO₂ levels were the highest in the Chinese products. As a result of the risk assessment, all the margins of exposure (MOE) values of Pb, except for Poria Sclerotium, were ≥1, indicating that most samples were safe. The hazard index (HI) for Cd, As, and Hg were <100%, indicating a safety level for food and medicine. In addition, the HI for SO₂ did not exceed 1 for any of the items, indicating safe levels.

• Journal of Intelligence and Information Systems
• /
• v.26 no.2
• /
• pp.105-129
• /
• 2020

This study uses corporate data from 2012 to 2018 when K-IFRS was applied in earnest to predict default risks. The data used in the analysis totaled 10,545 rows, consisting of 160 columns including 38 in the statement of financial position, 26 in the statement of comprehensive income, 11 in the statement of cash flows, and 76 in the index of financial ratios. Unlike most previous prior studies used the default event as the basis for learning about default risk, this study calculated default risk using the market capitalization and stock price volatility of each company based on the Merton model. Through this, it was able to solve the problem of data imbalance due to the scarcity of default events, which had been pointed out as the limitation of the existing methodology, and the problem of reflecting the difference in default risk that exists within ordinary companies. Because learning was conducted only by using corporate information available to unlisted companies, default risks of unlisted companies without stock price information can be appropriately derived. Through this, it can provide stable default risk assessment services to unlisted companies that are difficult to determine proper default risk with traditional credit rating models such as small and medium-sized companies and startups. Although there has been an active study of predicting corporate default risks using machine learning recently, model bias issues exist because most studies are making predictions based on a single model. Stable and reliable valuation methodology is required for the calculation of default risk, given that the entity's default risk information is very widely utilized in the market and the sensitivity to the difference in default risk is high. Also, Strict standards are also required for methods of calculation. The credit rating method stipulated by the Financial Services Commission in the Financial Investment Regulations calls for the preparation of evaluation methods, including verification of the adequacy of evaluation methods, in consideration of past statistical data and experiences on credit ratings and changes in future market conditions. This study allowed the reduction of individual models' bias by utilizing stacking ensemble techniques that synthesize various machine learning models. This allows us to capture complex nonlinear relationships between default risk and various corporate information and maximize the advantages of machine learning-based default risk prediction models that take less time to calculate. To calculate forecasts by sub model to be used as input data for the Stacking Ensemble model, training data were divided into seven pieces, and sub-models were trained in a divided set to produce forecasts. To compare the predictive power of the Stacking Ensemble model, Random Forest, MLP, and CNN models were trained with full training data, then the predictive power of each model was verified on the test set. The analysis showed that the Stacking Ensemble model exceeded the predictive power of the Random Forest model, which had the best performance on a single model. Next, to check for statistically significant differences between the Stacking Ensemble model and the forecasts for each individual model, the Pair between the Stacking Ensemble model and each individual model was constructed. Because the results of the Shapiro-wilk normality test also showed that all Pair did not follow normality, Using the nonparametric method wilcoxon rank sum test, we checked whether the two model forecasts that make up the Pair showed statistically significant differences. The analysis showed that the forecasts of the Staging Ensemble model showed statistically significant differences from those of the MLP model and CNN model. In addition, this study can provide a methodology that allows existing credit rating agencies to apply machine learning-based bankruptcy risk prediction methodologies, given that traditional credit rating models can also be reflected as sub-models to calculate the final default probability. Also, the Stacking Ensemble techniques proposed in this study can help design to meet the requirements of the Financial Investment Business Regulations through the combination of various sub-models. We hope that this research will be used as a resource to increase practical use by overcoming and improving the limitations of existing machine learning-based models.

• Korean Journal of Community Nutrition
• /
• v.15 no.3
• /
• pp.308-328
• /
• 2010

As the older adult period $({\geq}65y)$ is increasing, it is needed to investigate the trend of aging-dependent anthropomeric index and nutrient intake, and establish the more specific dietary guide for the different stages of aging period. To find the difference in nutrient intake among the Koreans aged 50-64, 65-74 and 75 years and older, and also any characteristics of dwellers in longevity area, we recruited 1,083 subjects (385 male and 698 female) aged 50-95 years (mean age, 71.3 yrs) living in Kugoksoondam area (Kurye, Goksung, Soonchang and Damyang counties), known as a longevity-belt region in Jeonlaprovince, Korea. We measured some anthropometric index and collected 2 day-dietary record. Nutrient intakes were analyzed by using DW24 program. The mean height and weight of subjects aged 75 years and older were lower than Korean national reference. BMI and obesity $({\geq}25kg/m^2)$ prevalence were significantly decreasing with aging. Underweight $(BMI<18.5kg/m^2)$ prevalence was also increasing with aging, especially in males, and it was slightly higher than national average, but similar to that in some other rural area. Obesity prevalence of male subjects was lower compared to national prevalence, but abdominal obesity prevalence $(waist{\geq}80cm)$ was very high in females (about 89%). In both genders, the average proportional contribution of carbohydrate, protein and fat to energy intake was not different between 65-74 years and 75 years and older. On overall, nutrient intake and quality of diet of females were inferior to those of males so that many of females aged 75 years and older assumed to be at risk of malnourished status. Fiber, folate and vitamin E intakes were substantially higher compared to those in 2007 KNHNES and other some studies in rural area. While almost nutrient %EAR was significantly decreased with aging in females, there was no significant difference in %EAR for protein, vitamin A, $B_1$, $B_6$, $B_{12}$, niacin, Ca and Zn between 65-74 years and 75 years and older in males. Vitamin $B_2$ for male aged 50-64 years, vitamin $B_2$ and Ca for male aged 65 years and over and female aged 50-74 years, and vitamin $B_2$, vitamin C, Ca and folate intake for female aged 75 years and older were assessed to be at risk to undernutrition based on the prevalence of intake below EAR. MAR of 13 nutrients and the number of nutrients consuming below EAR were significantly decreasing with aging in both genders, however, the number of nutrients of INQ < 1 and the average mini-nutritional assessment score were not significantly different between 65-74 years and 75 years and older. Taken together, decreasing tendency of nutrients intake and the quality of diet with aging was more evident in females than in males, and it is unique that our subjects consumed substantially higher fiber, folate and vitamin E compared to not only urban but also some other rural areas.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.25 no.6
• /
• pp.666-677
• /
• 2019

In order to understand the distribution of organic matter and heavy metal concentrations in the surface sediments of fishery resources protection areas (FRPAs), we measured the grain size, ignition loss (IL), chemical oxygen demand (COD), acid volatile sulfide (AVS), and concentrations of heavy metals (As, Cd, Cr, Cu, Fe, Hg, Pb, and Zn) in the surface sediments collected at 54 stations of 5 FRPAs (Gamak Bay, Yeoja Bay, Deukryang Bay, Wando coast, and Youngkwang coast) in the southwestern coast of Korea in February 2017. The surface sediments consisted of fine sediment such as mud, with 2.9~8.8Ø (7.4±0.1Ø) of mean grain size. The average concentrations of IL, COD, and AVS in the sediments were 4.63±0.96 %, 13.0±3.1 mgO₂/g·dry, and 0.092±0.124 mgS/g·dry, respectively, and were lower for sediments from the Youngkwang coast than those from other FRPAs. The average concentrations of heavy metals in the sediment were 7.5±0.9 mg/kg for As, 0.04±0.02 mg/kg for Cd, 70.2±9.7 mg/kg for Cr, 15.3±2.8 mg/kg for Cu, 3.3±0.5 % for Fe, 0.014±0.003 mg/kg for Hg, 25.0±6.0 mg/kg for Pb, and 99±14 mg/kg for Zn, respectively, and were relatively higher for sediments in the inner bays than those from the outer bays and coasts. Based on the assessment of sediment samples using the sediment quality guidelines (SQGs), the pollutant load index (PLI), and the ecological risk index (ERI), the surface sediments of FRPAs in the southwestern coast of Korea do not appear to be polluted by heavy metals, suggesting that the heavy metal concentrations in the sediments would not adversely impact aquatic and benthic organisms.