• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.251-261
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• 2022

Tuna purse seine fishery (TPF) constitute more than 60% of distant water fishery production in Korea based on a statistic of 2018, and 28 ships from four different companies were under operation at the western and central Pacific Ocean. On this research, common risk factors during TPF were investigated via enumeration of five years Korean fisherman's insurance payment statement, followed by some counterplans to diminish the accident rate. The accident rate of TPF on the Pacific Ocean peaked by 43.0% in 2014 and constantly decreased to 23.0% until 2018, presenting an average of 33.6%. Meanwhile, the accident rate on the Indian Ocean reached the highest point 55.1% in 2014 and declined to 11.6% in 2016, having an average of 24.7%. The average accident rate of the Indian Ocean scored 8.9% lower than the rate of the Pacific Ocean, but no statistic significance was observed. Depending on the process of operation, 'casting or hauling of net' was the most frequent part that people received an injury (40.4%). When the accidents were classified by their types, 'falling down' was the most recurrent cause of the injuries (28.5%). At the point of severity, the worst injuries were induced by crush hazard. Considering aforementioned accident frequency and severity, all the factors on the accident type list were divided into three different groups including high risk, moderate risk, and common risk. This study is expected to contribute to the reduction of occupational accidents during the work of fishermen and establishment of a safety management system for distance water fishing vessels.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.164-164
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• 2023

This study investigates the importance of flood-influencing factors on the accuracy of flood risk mapping using the integration of remote sensing-based and machine learning techniques. Here, the Extreme Gradient Boosting (XGBoost) and Random Forest (RF) algorithms integrated with GIS-based techniques were considered to develop and generate flood risk maps. For the study area of NAPA County in the United States, rainfall data from the 12 stations, Sentinel-1 SAR, and Sentinel-2 optical images were applied to extract 13 flood-influencing factors including altitude, aspect, slope, topographic wetness index, normalized difference vegetation index, stream power index, sediment transport index, land use/land cover, terrain roughness index, distance from the river, soil, rainfall, and geology. These 13 raster maps were used as input data for the XGBoost and RF algorithms for modeling flood-prone areas using ArcGIS, Python, and R. As results, it indicates that XGBoost showed better performance than RF in modeling flood-prone areas with an ROC of 97.45%, Kappa of 93.65%, and accuracy score of 96.83% compared to RF's 82.21%, 70.54%, and 88%, respectively. In conclusion, XGBoost is more efficient than RF for flood risk mapping and can be potentially utilized for flood mitigation strategies. It should be noted that all flood influencing factors had a positive effect, but altitude, slope, and rainfall were the most influential features in modeling flood risk maps using XGBoost.

• Korean Journal of Community Nutrition
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• v.13 no.1
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• pp.125-133
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• 2008

This study was carried out to compare bone density risk factors affecting women's BMD, and to examine the relationship age, lifestyle and dietary habits for bone health by physical measurement and questionnaires. The subjects of this study were 194 women living in the Seoul area. When the subjects were divided into normal and risk groups, BMD, height, weight, BMI, total body water, soft lean mass, fat free mass, protein, mineral, body-fat of normal group were much higher than those of the risk group. The breakfast eating rate of the normal group was much higher than that of the risk group, walking time was significantly longer and exercise was more (p < 0.05). The normal group had more frequent intakes of tunas, squid, radishes, the green parts of radish, cucumbers, carrots and Iucchinis, tomatoes, and grapes than the risk group (p < 0.01 or p < 0.05). In conclusion, breakfast eating, exercise, intakes of some foods such as anchovies, radishes, carrots, zucchinis and tomatoes were significantly important factor to prevent bone density risk.

• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.29-34
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• 2017

This Analyzed case study of measuring displacement, implemented laboratory investigation, and in-situ testing in order to interpret ground subsidence risk rating by excavation work. Since geological features of each country are different, it is necessary to objectify or classify quantitatively ground subsidence risk evaluation in accordance with Korean ground character. Induced main factor that could be evaluated and used to predicted ground subsidence risk through literature investigation and analysis study on research trend related to the ground subsidence. Major factors of ground subsidence might be classified by geological features as overburden, boundary surface of ground, soil, rock and water. These factors affect each other differently in accordance with type of ground that's classified soil, rock, or complex. Then rock could be classified including limestone element or not, also in case of the latter it might be classified whether brittle shear zone or not.

• Food Science and Industry
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• v.54 no.1
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• pp.2-10
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• 2021

Microplastics with a size of less than 5 mm have emerged as an important environmental and food safety issue, as they have been detected not only in marine but also in terrestrial ecosystem and drinking water. Although many studies have been conducted on the exposure of microplastics and the effects on human health, the lack of standardized experimental methods for microplastics has been reviewed as a major problem. In order to overcome this, European countries such as the Netherlands and Germany are conducting a project to develop detection methods for microplastics as well as to establish the risk assessment methodologies for microplastics. Being the microplastics suggested to have a substantially potential risk on human health, reliable risk assessments should be conducted considering the various sources of microplastics, chemical pollutants and biological factors. In addition, international standards and regulations should be applied.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.389-398
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• 2018

A nationwide survey of 8 N-nitrosamines in finished water samples from drinking water treatment plants (DWTPs) in Korea was conducted. The samples were pre-treated by solid-phase extraction (SPE) and analyzed using a gas chromatography coupled with tandem mass spectrometry (GC-MS/MS). According to the study results, four N-nitrosamines (NDMA, NDEA, NMOR, NDBA) were detected for three consecutive years, NMEA and NPYR were only found in samples collected in 2013. Two of these N-nitrosamines, N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA), have received attention and were the most commonly detected. The concentration of NDMA and NDEA in this study ranged from $0.002{\mu}g/L$ to $0.013{\mu}g/L$ and in $0.001{\mu}g/L$ to $0.008{\mu}g/L$, respectively. In comparison to studies performed in EPA(UCMR2), the concentrations of NDMA (from $0.002{\mu}g/L$ to $0.630{\mu}g/L$) and NDEA (from $0.005{\mu}g/L$ to $0.100{\mu}g/L$) observed in the this study were low.

• Ocean Systems Engineering
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• v.6 no.4
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• pp.377-400
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• 2016

Dropped objects are among the top ten causes of fatalities and serious injuries in the oil and gas industry (DORIS, 2016). Objects may accidentally fall down from platforms or vessels during lifting or any other offshore operation. Proper planning of lifting operations requires the knowledge of the risk-free zone on the sea bed to protect underwater structures and equipment. To this end a three-dimensional (3D) theory of dynamic motion of dropped cylindrical object is expanded to also consider ocean currents. The expanded theory is integrated into the authors' Dropped Objects Simulator (DROBS). DROBS is utilized to simulate the trajectories of dropped cylinders falling through uniform currents originating from different directions (incoming angle at $0^{\circ}$, $90^{\circ}$, $180^{\circ}$, and $270^{\circ}$). It is found that trajectories and landing points of dropped cylinders are greatly influenced by the direction of current. The initial conditions after the cylinders have fallen into the water are treated as random variables. It is assumed that the corresponding parameters orientation angle, translational velocity, and rotational velocity follow normal distributions. The paper presents results of DROBS simulations for the case of a dropped cylinder with initial drop angle at $60^{\circ}$ through air-water columns without current. Then the Monte Carlo simulations are used for predicting the landing point distributions of dropped cylinders with varying drop angles under current. The resulting landing point distribution plots may be used to identify risk free zones for offshore lifting operations.

• Journal of Korea Water Resources Association
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• v.49 no.9
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• pp.773-787
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• 2016

A coupled river-overland hydrodynamic model was applied to estimate flood risk by a scenario-based approach. The study area is Seongseo Industrial Complex in Daegu which is located near Nakdong river and Geumho river. Inundation depth and velocity at each time were calculated by applying a coupled 1D/2D hydrodynamic model to the target area of interest. The 2D inundation analysis for river and overland domain was performed with the scenario-based approach that there are levee overflow against 100/200 year high quantile (97.5%) design flood and levee break against 100/200 year normal quantile (50%) design flood. The level of flood risk was displayed for resident/industrial area using information about maximum depth and velocity of each node computed from the 2D inundation map. The research outcome would be very useful in establishing specified emergency action plans (EAP) in case of levee break and overflowing resulting from a flood.

• Journal of Korea Water Resources Association
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• v.55 no.6
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• pp.421-435
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• 2022

As natural disasters have been increasing due to climate change, sustainable solutions are in need to alleviate the degree of drought hazard, assess and project the drought influence based on future climate change scenarios. In assessing drought risk, socio-economic factors of the region must be considered along with meteorological factors. This study categorized drought hazard, exposure, and vulnerability as three major components of drought risk according to the Intergovernmental panel on Climate Change (IPCC) risk assessment framework, and selected indices for each component to quantify the drought risk in South Korea according to the mid-size basins. Combinations of climate scenarios (Representative Concentration Pathway; RCP 2.6 and RCP 8.5) and socio-economic scenarios (Shared Socio-economic Pathways; SSP 1, SSP2 and SSP3) for the near future (2030-2050) ant the far future (2080-2099) were utilized in drought risk analysis, and results were compared with the historical data (1986-2005). In general, the drought risks for all scenarios shows large increases as time proceeds to the far furture. In addition, we analyzed the rank of drought hazard, exposure, vulnerability for drought risk, and each of their contribution. The results showed that the drought hazard is the most contributing component to the increase of drought risk in future and each basin shows varying contributing components. Finally, we suggested countermeasures for each basin according to future climate change scenarios, and thus this study provides made the basis for establishing drought management measures.

• The Research Journal of the Costume Culture
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• v.26 no.3
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• pp.450-470
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• 2018

This study examined the risk components and risk types perceived in the context of purchasing decisions of paper fashion products. This study also identified the levels of perceived risk by consumers and the differences between age groups in risk perception. First, qualitative data were collected through a focus group interview with 7 Korean females in their 20s to 50s. The interviewees were presented with two types of paper materials (undyed and dyed Jumchi-Hanji) and products (bags and wallets) made with the papers. The interviewees mentioned 11 risk components which were classified into five types of risks: performance (easily torn/lack of durableness, lint/pilling/wear-out, lack of water-resistant, no washability, and deformation and discoloration over time), social-psychological (old and traditional image), aesthetic (lack of design diversity, unsatisfactory appearance due to repair), financial (expensive price, lack of usability in daily life) and time/convenience (difficulty in handling) risks. Based on the results of the interview, a measurement for evaluating the risk perception of paper fashion products was developed. Second, quantitative data were collected from 64 Korean women in their 20s to 50s using the measurement. Respondents who were presented with the paper materials and the products perceived the performance risk more strongly than the social-psychological risk and aesthetic risk. In addition, differences between age groups were found: younger respondents perceived performance risk and social-psychological risk more strongly than older respondents, but older respondents perceived financial risk more than younger respondents. Based on this study, strategies for the risk reduction of paper fashion products were proposed.