• Journal of Internet Computing and Services
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• v.22 no.1
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• pp.65-77
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• 2021

COVID-19 has recently impacted the world with the large numbers of infected and deaths. The development of effective COVID-19 vaccine has not been successful. Hence, people have a high concern on the infection of this disease. The infection information from the governmantal public organizations are mainly based on simple summary statistics. Consequently, it is hard to assess the infection risks of individual person and the current location of the person. In this paper, we present a machine learning-based software system that analyzes COVID-19 infection risks and guidelines for safe activities.This paper proposes a suite of risk factors regarding COVID-19 infection and deaths and methods to quantitatively measure the individual and group risks using the proposed metrics. The proposed system utilizes a clustering algorithms and various software approaches that reflect the information and features of inviduals and their geograpical locations.

• Journal of Science and Technology Studies
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• v.19 no.3
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• pp.119-166
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• 2019

The risk of electromagnetic field(EMF) from power lines has been heavily disputed whenever high-voltage power line towers were built in South Korea. Local communities and civic groups had regarded burying the lines in the ground as an alternative to building power line towers. In 2014, however, when an elementary school science teacher reported the results of EMF measurements over the underground power lines to the Asian Citizens' Center for Environment and Health (ACCEH), the risk controversy over underground power lines took a whole new turn. The level of EMF from underground power lines turned out to be higher, and therefore more harmful than that from power line towers. In the debates that took place from then on over the EMF risk, ACCEH and NIER(National Institute of Environmental Research) presented conflicting topographies of EMF risk. This paper examines measuring practices of ACCEH and NIER by analyzing the measuring sites, measuring devices, and measuring heights chosen by each organization. This paper further examines how ACCEH and NIER mobilized various standards(EMF exposure limit, measurement guideline, categorization of carcinogens) differently. This controversy on the EMF from underground power lines of Seoul has raised concerns on the non-thermal effects of EMF in the long-term exposure and has led people to question whether burying the power lines is the safe alternative to building power line towers. Furthermore, this suggests conflicting answers on whether Seoul, where 90 % of transmission lines were already buried, is a safely managed place or not.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.483-491
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• 2021

The identification of regional collision risks in water areas is significant for the safety of navigation. This paper introduces a new method of collision risk assessment that incorporates a clustering method based on the distance factor - hierarchical clustering - and uses real-time data in case of several surrounding vessels, group methodology and preliminary assessment to classify vessels and evaluate the basis of collision risk evaluation (called HCAAP processing). The vessels are clustered using the hierarchical program to obtain clusters of encounter vessels and are combined with the preliminary assessment to filter relatively safe vessels. Subsequently, the distance at the closest point of approach (DCPA) and time to the closest point of approach (TCPA) between encounter vessels within each cluster are calculated to obtain the relation and comparison with the collision risk index (CRI). The mathematical relationship of CRI for each cluster of encounter vessels with DCPA and TCPA is constructed using a negative exponential function. Operators can easily evaluate the safety of all vessels navigating in the defined area using the calculated CRI. Therefore, this framework can improve the safety and security of vessel traffic transportation and reduce the loss of life and property. To illustrate the effectiveness of the framework proposed, an experimental case study was conducted within the coastal waters of Mokpo, Korea. The results demonstrated that the framework was effective and efficient in detecting and ranking collision risk indexes between encounter vessels within each cluster, which allowed an automatic risk prioritization of encounter vessels for further investigation by operators.

• Journal of Life Science
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• v.19 no.4
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• pp.492-501
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• 2009

The purpose of this study was to examine the most effective weight training (WT) intensity for the improvement of metabolic syndrome factors in overweight high school students. Sixty overweight high school students were randomly divided into 4 groups (15 subjects/group) according to WT intensity: A group - control group, B group - 40-55% repetition maximum (RM) group, C group - 60-75% RM group, and D group - 80-90% RM group. They exercised between 60-70 minutes a day, three times a week, for eight weeks. In order to determine the most effective WT intensity, five metabolic syndrome factors--waist size, fasting glucose, triglyceride (TG), high-density lipoprotein-cholesterol (HDL-C) and blood pressure--were measured for each subject prior to and after the experiment. Waist size decreased in all exercise groups, but the results were more prominent in the 40-55% RM and 60-75% RM groups. TG levels also decreased in all groups but results were more prominent in the 40-55% RM group. HDL-C levels in the 80-90% RM group were significantly higher than the control group. Groups did not show any significant difference in the diastolic blood pressure, but the 40-55% RM group's systolic blood pressure significantly decreased compared to other groups. Groups did not show significant difference in the fasting glucose level. These results indicate that lower-intensity weight training is generally more effective than the higher-intensity weight training in improving metabolic syndrome factors in overweight high school students and that the most effective WT intensity is 40-55% RM.

• The Journal of the Acoustical Society of Korea
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• v.34 no.2
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• pp.138-145
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• 2015

Although it is well-known that environmental noise can lead to hearing loss in individuals, the true extent of subway noise effects in the general population remains poorly understood. The purpose of the present study is to see changes of acoustic reflex thresholds and speech perception scores when passengers listen to music presented from their personal listening device in the subway. Forty subjects with normal hearing participated being divided into two groups, experimental and control groups. As a baseline, all subjects were measured by acoustic reflex thresholds in five test frequencies and Korean speech perception in noise (KSPIN) test at 0 and -5 dB SNR. In the experiment, the control group read newspaper or magazine in the subway noise, whereas the experimental group listened to music presented from their smartphone under the subway noise through speakers at 73.45 dBA for 60 min. After completing the experiment, two groups also conducted both acoustic reflex thresholds and KSPIN tests in the same condition as the baseline. The results showed that there was a significant difference of correct percent in speech-in-noise test between experimental and control groups and of that between two signal-to-noise ratios, which means the double noise exposure of 60 min might cause some degradation of speech perception when noise increases compared to only subway noise condition that was not statistically significant difference. We concluded that a risk of some degraded speech perception ability would be expected when passengers have a habit of listening to music in the subway noisy situation for a long duration.

• Korean Journal of Occupational Health Nursing
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• v.29 no.4
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• pp.288-294
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• 2020

Purpose: This study aimed to comprehensively examine middle-aged male taxi drivers' perceptions of the risk of cardiovascular disease. Methods: A qualitative method was used, with focus group interviews. The participants were middle-aged male taxi drivers who had been driving for more than ten years and for more than six hours daily. Results: The data were analyzed using qualitative thematic analysis. Middle-aged male taxi drivers' perceptions of the risk of cardiovascular disease were categorized into three main themes: "individual perceptions of cardiovascular disease", "possibility of behaviors for cardiovascular disease" and "motivations of behaviors for cardiovascular disease". Six sub-themes were extracted as follows: "perception of vulnerability", "perception of seriousness", "perception of profitability", "perception of disability", "self-awareness" and "advancing toward health care". Conclusion: It is necessary to invigorate support systems through measures including education, counseling, and web-based programs to prevent cardiovascular disease in middle-aged male taxi drivers.

• Journal of the Korean Data and Information Science Society
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• v.23 no.1
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• pp.113-120
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• 2012

When we evaluate prospective students in the interview process, we have to implement a system in which each student can be fairly judged. This process, the standardization of the scores which the interviewers have produced based on a student's performance, is implemented to ensure that each student receives a score that objectively translates one's performance. Although we don't know exactly how effective the standardization is in many different cases, we have researched which standardization methods are most stable and have minimum risks among the four methods such as STD, Range, MAD and IQR. These methods use scales such as standard deviation, range, maximum median and interquartile range.

• Journal of Hydrogen and New Energy
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• v.33 no.4
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• pp.383-390
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• 2022

Appropriate explosion proof electrical equipment should be installed in hazardous areas. In areas where hydrogen is handled, explosion proof electrical equipment adjacent to the hydrogen handing facility must be reviewed for selection of gas group IIC (or IIB+H₂) equipment. When selecting explosion proof electrical equipment for the flammable substance handling facility in areas where hydrogen and flammable substance are handled, the method to avoid gas group IIC (or IIB+H₂) equipment has been suggested by using the operating pressure of the hydrogen handling facility. When the operating pressure of the outdoor hydrogen handling facility is 1.065 MPa or less, it has been confirmed that there is no need to install gas group IIC (or IIB+H₂) equipment for the flammable substance handling facility adjacent to the hydrogen handling facility. And the method of selecting explosion proof electrical equipment for the flammable substance handling facility has been suggested as a flowchart, so it will be able to be utilized when selecting appropriate explosion proof electrical equipment.

• Convergence Security Journal
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• v.22 no.5
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• pp.61-67
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• 2022

The purpose of this study is to analyze research trends in artificial intelligence. For a three-dimensional analysis, an attempt was made to objectively compare and present the difference between the research direction of artificial intelligence in social science and engineering. For the research method, topic modeling was used among the big data analysis methodologies, and 1000 English papers searched with the keyword artificial intelligence (AI) in the academic research information system were used for the analysis data. As a result of the analysis, in the field of social science, it was possible to identify groups formed around the keywords of 'human', 'impact', and 'future' for artificial intelligence, and in the field of engineering, 'artificial intelligence-based technology development', 'system', 'Groups such as 'Risk-Security' were formed.

• International Journal of Highway Engineering
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• v.13 no.4
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• pp.177-185
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• 2011

In order to reduce traffic accidents at long road sections involving high risks of traffic accidents, including tunnels, bridges or curves, the National Police Agency have decided a tentative installation and operation of an automated point-to-point speed enforcement system based on cameras at January, 2007. The first system was established at the direction to Kangreung of Dunnae Tunnel at December, 2007. Currently, the automated point-to-point speed enforcement system operates at 11 sections including eight sections on expressways and three sections on national highways. However, there have been few researches on the effects of the system upon the reduction of traffic accidents in a scientific way. To this end, this research effort was initiated to evaluate the effect of the automated point-to-point speed enforcement system on traffic safety by comparing the number of traffic accidents before and after the installation of the system using a comparison-group(C-G) method. Three-year-long traffic accident data for the expressways were collected in order to evaluate the system. As a result, the installation of the system was found to reduce traffic accidents by 49.97% in average.