• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.27-31
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• 2018

Classification of explosion hazard areas is very important in terms of cost and safety in the workplace handling flammable materials. This is because the radius of the hazardous area determines whether or not the explosion-proof equipment is installed in the electrical machinery and apparatus. From November 6, 2017, KS C IEC-60079-10-1: 2015 will be issued and applied as a new standard. It is important to understand and apply the difference between the existing standard and the new standard. Leakage coefficients and compression factors were added to the leakage calculation formula, and the formula of evaporation pool leakage, application of leakage ball size, and shape of explosion hazard area were applied. The range of the safety factor K has also been changed. Also, in the radius of the hazardous area, the existing standard applies the number of ventilation to the virtual volume, but the revised standard is calculated by using the leakage characteristic value. In this study, we investigated the differences from existing standards in terms of ventilation and dilution and examined the effect on the radius of the hazard area. Comparisons and analyzes were carried out by applying revised standards to workplaces where existing explosion hazard locations were selected. The results showed that even if the ventilation and dilution were successful, the risk radius was not substantially affected.

• Journal of Nutrition and Health
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• v.45 no.1
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• pp.20-29
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• 2012

Metabolic syndrome (MetS) has become a global epidemic. In particular, it is known that there is a dramatic increase in the prevalence of MetS among women during the postmenopausal period. Recently, accumulating studies have suggested that vitamin D deficiency may be inversely associated with the risk factors regarding MetS. However, evidence from postmenopausal women is limited. In this study, we examined the association between the serum 25-hydroxyvitamin D [25(OH)D] and the MetS in Korean adult women aged 20-69 years (n = 2,618) by using the 2007-2008 Korean National Health and Nutrition Examination Survey data. The geometric mean of plasma 25(OH)D were $17.16{\pm}6.28\;ng$/mL and $20.20{\pm}7.69\;ng$/mL for premenopausal and postmenopausal women, respectively. The percentages of vitamin D deficiency [25(OH)D < 12 ng/mL] were 22.5% and 14.4%, respectively. MetS was more prevalent in postmenopausal women (43.0%) compared with premenopausal women (11.2%). When serum concentrations of 25(OH)D were categorized in quintiles, there was no relationship in the prevalence of MetS in both premonopausal and postmenopausal women. However, in premenopausal women, compared with the lowest 25(OH)D quintile, the odds ratio for hypertriglyceridemia in the highest quintile was 0.57 (95% CI 0.34-0.95, $P_{trend}$ = 0.041) and for low serum HDL cholesterol 0.60 (95% CI 0.42-0.85, $P_{trend}$ = 0.014) after adjusting for all potential confounders. On the other hand, we observed the tendency of an inverse relationship for 25(OH)D regarding low serum HDL cholesterol (OR 0.78, 95% CI 0.50-1.22, $P_{trend}$ = 0.029) and a direct relationship with abdominal obesity (OR 1.94, 95% CI 1.01, 3.74, $P_{trend}$ = 0.049) in postmenopausal women. Further studies are needed to confirm these findings in other research settings.

• Spatial Information Research
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• v.14 no.4 s.39
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• pp.363-377
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• 2006

Mean annual soil loss was calculated and critical soil erosion areas were identified for the Congaree River Basin in South Carolina, USA using the Revised Universal Soil Loss Equation (RUSLE) model. In the RUSLE model, the mean annual soil loss (A) can be calculated by multiplying rainfall-runoff erosivity (R), soil erodibility (K), slope length and steepness (LS), crop-management (C), and support practice (P) factors. The critical soil erosion areas can be identified as the areas with soil loss amounts (A) greater than the soil loss tolerance (T) factor More than 10% of the total area was identified as a critical soil erosion area. Among seven subwatersheds within the Congaree River Basin, the urban areas of the Congaree Creek and the Gills Creek subwatersheds as well as the agricultural area of the Cedar Creek subwatershed appeared to be exposed to the risk of severe soil loss. As a prototype model for examining future effect of human and/or nature-induced changes on soil erosion, the RUSLE model customized for the area was embedded into ESRI ArcGIS ArcMap 9.0 using Visual Basic for Applications. Using the embedded model, users can modify C, LS, and P-factor values for each subwatershed by changing conditions such as land cover, canopy type, ground cover type, slope, type of agriculture, and agricultural practice types. The result mean annual soil loss and critical soil erosion areas can be compared to the ones with existing conditions and used for further soil loss management for the area.

• Management & Information Systems Review
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• v.37 no.1
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• pp.41-53
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• 2018

This study validates the trading rules based market anomalies and technical analysis in the Korean stock market. For the analysis, we built decile portfolios on the basis of corporate characteristics factors that clearly demonstrate specific patterns of stock returns including the firm size, book-to-market equity, and accruals. This portfolio was used to develop a portfolio based on the moving average trading strategy which was used for popular technical analysis tools, and then that was evaluated using the Sharpe ratio. We also created a zero-cost portfolio to identify the profitability and success rate of the moving average trading strategy. We lastly sought to ensure a more robust evaluation by calculating the Sortino ratio of the portfolio based on the moving average trading strategy with various lags. Key findings from this validation are as follows. First, a smaller firm size, a higher book-to-market equity, and lower accruals led to larger average returns. Second, the risk-adjusted performance of the moving average trading strategy was the highest in terms of the firm size, followed by book-to-market equity and accruals. Third, the returns of the zero-cost portfolios all had a positive value, with its overall success rate hovering over 68.8%, demonstrating the successfulness of the moving average trading strategy. Fourth, various evaluations revealed the economic usefulness of our trading strategy that used market anomalies and technical analysis.

• Journal of Wetlands Research
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• v.6 no.4
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• pp.59-69
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• 2004

Constructed wetlands are regarded as an important water treatment system for agricultural water quality improvement and management. The purpose of this study is to evaluate the application of subsurface flow wetland(SFW), using the Pharagmites australis as macrophytes, and to clarify the basic and essential factors to be considered in the construction and management of constructed wetlands. This study was carried out relatively short hydraulic residence time(HRT), 6hr ~ 72hr (3days), using eutrophic reservoir water with relatively low concentrations of influent and large quantity to be treated. The effluent satisfied the criteria of agricultural water quality. Removal efficiencies of Biochemical oxygen demand(BOD), Chemical oxygen demand(COD), Suspended solids(SS) and Chlorophyll a(Chl-a) were high in HRT 24hr, not any more significant increasement of removal efficiencies in HRT 48hr and 72hr. However, removal efficiencies of nitrogen and phosphorus increased as HRT increased, showing the highest efficiency at the 72hr of HRT in nitrogen, and 48hr in phosphorous. The SFW was very effective system for reservoir water quality improvement, and had the advantages of the reduction of purchasing cost to land required, lack of odors, and harmful insects, especially mosquito, the improvement of the scenic beauty and minimal risk of public exposure. Therefore, it was evaluated that the SFW was very available water treatment system for the water quality improvement of agricultural reservoir. However, it was need to consider with application of the SFW in high cost of construction and troublesome of management.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.539-549
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• 2016

This study analyzed ship's passing characteristics in relation with incoming and outgoing routes in Yeosu Gwangyang Port, and examined the risk factors and measures for safety management of marine traffic. The number of passing ships in Yeosu Gwangyang Port was about 60,000 ships annually based on 2014, and the tonnage rose 73% from 447,000 thousand tons in 2005 to 770,000 thousand tons in 2014. Actually, the number of large passing ships was revealed to enormously increase. As a result of marine traffic survey in Yeosu Gwangyang Port for three days in August 2015, daily average passing ships were 408 ships, and 77% of the total passing ships passed between 04:00 and 20:00. The chemical ships and general cargo ships took up the most at 58% of the total incoming and outgoing ships, followed by other work ships at 21%, tankers at 8%, fishing vessels at 7.5% and container ships at 5.5%. Concerning the size of passing ships, ships less than 1,000 tons accounted for 58.6% of the total passing ships. Ships of 1,000-5,000 tons were 20.1%, and those of 5,000-10,000 tons were 6.8%, and more than 10,000 tons were 14.4%. Especially, ships of 500 tons and less using mainly coastal passing routes took up 49% of the total passing ships. As for ship's passage ratio by route, Nakpo sea area where many routes meet accounted for 27.2%, specified area 49%, costal route 8%, specified area's incoming and outgoing sea area around Daedo 4.5%, and Dolsan coastal ara and Kumhodo sea area 8.5%. The number of ships standing by for anchoring in the six designated anchorages was 230 for three days. The standby rate for anchoring was 25% based on the specified area passing ships. In Nakpo sea area, where many routes meet, parallel passing and cross passing between ships occurred the most frequently. In the specified area, many cases, in which incoming and outgoing cargo ships at the starting and ending parts and incoming and outgoing work ships and fishing vessels at the coastal routes cross, took place. Consequently, the following measures are urgently needed: active passing management in the Nakpo sea area, where passing routes are complex, specified areas and costal traffic routes, the elimination of rocks in the route close to Myodo, an effort to improve routes including shallow depth area dredging, and rational safety management for small work ships frequently incoming and outgoing the passing routes of large ships, and fishing vessels operated in the sea areas around those passing routes.

• Tuberculosis and Respiratory Diseases
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• v.82 no.2
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• pp.102-117
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• 2019

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive fibrosing interstitial pneumonia, which presents with a progressive worsening dyspnea, and thus a poor outcome. The members of the Korean Academy of Tuberculosis and Respiratory Diseases as well as the participating members of the Korea Interstitial Lung Disease Study Group drafted this clinical practice guideline for IPF management. This guideline includes a wide range of topics, including the epidemiology, pathogenesis, risk factors, clinical features, diagnosis, treatment, prognosis, and acute exacerbation of IPF in Korea. Additionally, we suggested the PICO for the use of pirfenidone and nintendanib and for lung transplantation for the treatment of patients with IPF through a systemic literature review using experts' help in conducting a meta-analysis. We recommend this guideline to physicians, other health care professionals, and government personnel in Korea, to facilitate the treatment of patients with IPF.

• Journal of Korean Foot and Ankle Society
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• v.26 no.2
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• pp.95-102
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• 2022

Purpose: This study was based on the Korean Foot and Ankle Society (KFAS) member survey and aimed to report the current trends in the management of syndesmotic injuries over the last few decades. Materials and Methods: A web-based questionnaire containing 36 questions was sent to all KFAS members in September 2021. The questions were mainly related to the preferred techniques and clinical experiences in the treatment of patients with syndesmotic injuries. Answers with a prevalence ≥50% of respondents were considered a tendency. Results: Seventy-six (13.8%) of the 550 members responded to the survey. The results showed that the most preferred method to diagnose a syndesmotic injury was magnetic resonance imaging (MRI). Intraoperatively, the external rotation stress test and the Cotton test were most frequently used to confirm syndesmotic diastasis. The reduction was usually done by a reduction clamp. One 3.5-mm screw was used most frequently over three cortices at 2~4 cm above the ankle joint. The preferred ankle position during fixation was 0° dorsiflexion. Removal of the syndesmotic screw was routinely done by most surgeons, mainly because of the limitation of movement and risk of screw breakage. Factors that affect suture button selection included non-rigid fixation which enables adequate fixation, early weight-bearing, and an infrequent need to remove the hardware. Inadequate reduction was considered the main factor that affects poor prognosis. Conclusion: This study proposes updated information about the current trends in the management of syndesmotic injuries in Korea. Consensuses in both the diagnostic and therapeutic approach to patients with syndesmotic injury were identified in this survey study. This study may raise the awareness of the various possible approaches toward the injury and should be used to further establish a standard protocol for the management of syndesmotic injuries.

• Korean Journal of Construction Engineering and Management
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• v.24 no.5
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• pp.44-51
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• 2023

Selecting appropriate bidding system in construction projects considering the characteristic of project can be a make-or-break element, so the understanding for bidding system of public construction projects is ever more important from the perspective of both the owner and the contractor. The design-build bidding is commonly referred to as turnkey in Korea, and is a bidding method that is often applied to large public construction projects because it allows new technologies to be applied to the design and facilitates risk management for the owner. In this bidding method, there are only two factors (design score and price score) that affect the selection of the winning bidder, so it is important to understand the influence of each factor, but there is little research on the subject. This study aims to provide a basis for establishing bidding strategies for understanding the influence between design score and price score by analyzing various design-build bidding data of public construction projects. The results of the study show that design score is the factor that has more influence on the ranking of bidders in all three weighted evaluation methods: design-emphasized, price-emphasized, and equalized evaluation. In addition, we found that the correlation between design and price scores was not significant due to the unique bid evaluation structure in Korea.

• Land and Housing Review
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• v.15 no.4
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• pp.33-41
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• 2024

This research proposes a monitoring system using Unmanned Ground Vehicles (UGVs) to address the issue of ground subsidence in urban areas. In environments where Unmanned Aerial Vehicles (UAVs) face limitations due to urban obstacles, UGVs offer an effective alternative. This research aims to equip UGVs with various sensors, establish adaptive sensing management suitable for urban ground subsidence monitoring, and evaluate their effectiveness. The study involves creating a risk map by identifying areas with a high likelihood of subsidence and categorizing them into monitoring zones (M zones) that require frequent monitoring and saving zones (S zones) that allow for energy saving. A strategy is proposed to adjust the sensing intervals of the navigation sensor (NS), which detects the UGV's location, and the monitoring sensor (MS), which monitors subsidence-related factors, according to these zones. Tests simulating typical urban deep excavation scenarios confirmed that adjusting the sensing intervals of MS and NS reduces energy consumption substantially. The study highlights the importance of optimizing energy consumption based on the UGV's monitoring path, suggesting that this approach can enhance urban safety by effectively monitoring ground subsidence.