• Journal of Convergence for Information Technology
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• v.11 no.1
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• pp.136-142
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• 2021

Open-pit mine development requires continuous management because of topographical changes and there is a risk of accidents if the current status survey is performed directly in the process of calculating the earthwork. In this study, the application of UAV photogrammetry, which can acquire spatial information without direct human access, was applied to open-pit mines development area and analyzed the accuracy, earthwork, and mountain restoration plan to determine its applicability. As a result of accuracy analysis at checkpoint using ortho image and Digital Surface Model(DSM) by UAV photogrammetry, Root Mean Square Error(RMSE) is 0.120 m in horizontal and 0.150 m in vertical coordinates. This satisfied the tolerance range of 1:1,000 digital map. As a result of the comparison of the earthwork, UAV photogrammetry yielded 11.7% more earthwork than the conventional survey method. It is because UAV photogrammetry shows more detailed topography. And result of monitoring mountain restoration showed possible to determine existence of rockfall prevention nets and vegetation. If the terrain changes are monitored by acquiring images periodically, the utility of UAV photogrammetry will be further useful to open-pit mine development.

• 한국사회정책
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• v.24 no.4
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• pp.113-150
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• 2017

This study analyzes how workers become impoverished and have their jobs less stabilized after they suffer from non-job-related sickness. Given that South Korea lacks sickness benefits, which most of OECD member states legislate and implement except US and Switzerland, this study examines its impact on laborers' job stability and povertization in Korea. The researchers have conducted in-depth interviews with nine former or present laborers who have the experiences and four experts on the issue in July-September, 2017 for the qualitative analysis. It is found that laborers, after becoming aware of their sickness, at first endure their pain without informing their employers not to lose their jobs. The attititude is observed especially among non-standard laborers, because sickness more often leads to job loss for them than for standard laborers. After workers have to leave their jobs due to their sickness in the end, they have no choice but to keep working in less stable jobs to compensate for income losses. They become gradually impoverished with their social capital like family bond declining. We observe laborers who are eligible for industrial accident insurance compensation could not benefit from the system because some employers refrain from the legal reporting duty. Due to this illegal practices, some industrial accident victims unduly lose their jobs due to "non-job-related sickness". Second, some employers report to the authority that their sick laborers have left their jobs 'voluntarily' even when they have quitted it without their volition, in which case the newly unemployed are not eligible for unemployment benefits. Large holes in Korea's safety nets for those suffering from multiple risks of sickness and unemployment.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.550-556
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• 2021

The scissor-type rope cutter is the most widely used amongst all kinds of commercially available rope cutters in Korea. In this study, we performed finite element analysis on the scissor-type rope cutter. We determined the structure of the cutter that would ensure its stable operation in various situations involving rope entanglement, and verified its effectiveness by testing it in the lab and in an actual ship. These investigations revealed that when the propeller shaft was not rotated by rope entanglement, the constant torque generated by the engine resulted in the torsion of the rope cutter and maximum deformation in the lower blade, which was not restricted by finite element analysis. With increasing blade thickness, the maximum values of deformation and equivalent stress decreased, resulting in a rise in the safety factor. At the constant blade thickness, the effect of the torque variations on the maximum equivalent stress and the maximum deformation is independent of the position of the external force of the rope cutter and decreases in direct proportion. The results of this study confirmed that the rope-cutter structure determined by analysis could lead to a hassle-free removal of ropes and fishing nets under all conditions and environments.

• The Journal of the Korea Contents Association
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• v.20 no.12
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• pp.154-165
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• 2020

With a long-lasting pandemic of COVID-19, we have faced unprecedented socioeconomic threats. The regulation of human exchange has exposed us not only to the threat of health and medical care problems, but also to the burden of the contraction of economic activity. The outbreak of COVID-19 did give us an opportunity to reexamine the social safety net which has been prepared for such crisis situations. The current study, in this vein, aims to investigate the impact of evaluations of social safety nets on the trust in government and on individual willingness to accept tax increases. To this end, this study has explored the data from a survey conducted on 1,000 adult men and women across the country (South Korea) in May, 2020, when COVID-19 has entered a pandemic phase. The analysis result then has shown that the evaluation of social safety net after the outbreak of COVID-19 had a positive impact on the trust in the government, which in turn led to the increase of the willingness to accept tax increases. Moreover, the positive impact of trust in government on the willingness to accept tax increases has been more amplified when the income level was increased. These results could contribute to laying the theoretical foundation for restructuring the policies and systems for the post COVID-19 era.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.81-87
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• 2021

Many merchant ships sail in the waters surrounding Jeju Island and many fishing vessels catch fish using gill nets, trolling lines, and so on. Meanwhile, marine waste has collected in the coastal waters of Jeju Island. However, there has been little research on the collection of marine waste in coastal waters. In this study, marine waste deposited in Jeju Island's northwest sea was collected using Jeju National University's training ship, and related vessels were analyzed for each gear type. According to the results, most coastal waters had abandoned fishing grounds, which were from fishing vessels, and a large proportion of them was gill net and trap fishing gear. To analyze how much marine waste is accumulating in a certain area and ship's stay time, we use automatic identification system (AIS) data to extract the time spent in the target sea, and the amount of marine waste per hour was analyzed in a unit distance of 1 ㎢. The average amount of marine waste generated per hour in the unit area was found to be 0.94 kg for gillnet fishing gear, 3.49 kg for trap fishing gear, 0.10 kg for trawl fishing gear, 0.11 kg for longline fishing gear, and 0.02 kg for other fishing gear.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.632-638
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• 2022

As Korean coastal activity is high, the incidence of accidents caused by marine waste is extensive. An accident in which marine floating waste ropes and fishing nets are wound around the propeller of a sailing ship is termed "Rope wrapped accident." To prevent such accidents, this study applied the Finite Element Method (F.E.M.) for performance evaluation of the shaver type cutter, commercialized in Korea, through a structural safety review and water tank test. The results demonstrate that all parts constituting the rope cutter were damaged before reaching 0.5s, and the safety factor of each part was found to be at least 2 based on the maximum stress generated compared to the tensile strength. In the basin test, the cutting process of the shaver type rope cutter was reviewed, and the installation angle was set for each case considering that the rope floating in the sea actually enters at various angles. Consequently, as it was successful at cutting in all the cases, it can be concluded that there will be no problem in cutting the rope regardless of the mounted angle of the cutting blade.

• Journal of Advanced Navigation Technology
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• v.26 no.3
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• pp.172-178
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• 2022

In this paper, water meter AMR(automatic meter reading), one of the core technologies of smart water grid, using LoRa IoT network is studied. The main content of the research is to develop the network system and show the test results that one PC server receives the readings of water meters from multiple households through LoRa communication and stores them in the database, and at the same time sends the data to the web server database through internet. The system also allows users to monitor the meter readings using their smartphones. The hardware and firmware of the main board of the digital water meter are developed. For a PC server program, MDMS(meter data management system) is developed using Visual C#. The app program running on the user's smartphone is also developed using Android Studio. By connecting each developed parts, the total network system is mounted on a flow test bench in the laboratory and tested. For the fields test, 5 places around the university are selected and the transmission distances are tested. The test result show that the developed system can be applied into the real field. The developed system can be expanded to various social safety nets such as monitoring the living alone or elderly with dementia.

• Journal of Korea Entertainment Industry Association
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• v.15 no.3
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• pp.289-295
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• 2021

Today, the most important factor affecting the quality of human life is thought to be due to the environment. The importance of environmental monitoring systems to improve human life and improve welfare as the magnitude of the damage increases year by year due to the rapid increase in the frequency of hail, typhoons, collapse of incisions, landslides, etc. Is increasing day by day. Among environmental problems, problems caused by water quality have a very high proportion, and as there is a growing concern that the scale of damage will increase when water pollution accidents occur due to urbanization and industrialization, the demand for social water safety nets is increasing. have. In the last 5 years, 259 cases of water pollution (Han River 99, Nakdong River 31, Geum River 25, Seomjin River and Yeongsan River 19, and 85 others) have occurred in the four major river basins. Caused damage. Therefore, it is required to establish a water quality environment management strategy system based on big data that can minimize the uncertainty of the water quality environment by expanding the target of water quality management from the current water quality management system centered on the four major rivers to small and medium-sized rivers, tributaries/branches, and reservoirs. In this paper, we intend to construct and analyze a water quality monitoring system based on big data that can present useful water quality environment information by analyzing the water quality information accumulated for a long time.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1329-1341
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• 2022

Destroying the marine environment and marine ecosystem and causing marine accidents, marine debris is generated every year, and among them, submerged marine debris is difficult to identify and collect because it is on the seabed. Therefore, deep-learning-based semantic segmentation was experimented on waste fish nets and waste ropes using underwater images to identify efficient collection and distribution. For segmentation, a high-resolution network (HRNet), a state-of-the-art deep learning technique, was used, and the performance of each optimizer was compared. In the segmentation result fish net, F1 score=(86.46%, 86.20%, 85.29%), IoU=(76.15%, 75.74%, 74.36%), For the rope F1 score=(80.49%, 80.48%, 77.86%), IoU=(67.35%, 67.33%, 63.75%) in the order of adaptive moment estimation (Adam), Momentum, and stochastic gradient descent (SGD). Adam's results were the highest in both fish net and rope. Through the research results, the evaluation of segmentation performance for each optimizer and the possibility of segmentation of marine debris in the latest deep learning technique were confirmed. Accordingly, it is judged that by applying the latest deep learning technique to the identification of submerged marine debris through underwater images, it will be helpful in estimating the distribution of marine sedimentation debris through more accurate and efficient identification than identification through the naked eye.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.906-917
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• 2022

This study aimed to compare differences according to categories of fishery and marine environmental policies for the (estimated) amount of fishery waste generated by fishing, and to analyze the correlation between associated independent and dependent variables. The independent variables were divided into three dif erent sectors. The first sector included precautionary policies that observed eco-friendly fishing support program, institutional prevention activities, and physical barriers installation. The second sector with the current management policies included the relevant vessel operations, establishment of fishery order, fishery restructuring, and fishery ground clean-up. Thirdly, post-response policies comprised the litter purification from river to shoreline, the collection and removal of marine, sedimentary, and floating debris, purchasing salvaged debris generated while fishing, fishery waste disposal, and repairing damage caused by marine litter. The indicator used was the settlement amount by each program. The dependent variable was the estimated amount of fishery waste and the indicator was the sum of the loss of traps and gill nets and the loss of their appendages. According to the results of Kruskal-Wallis Test, the estimated amount of fishery waste was highest in the East Sea in terms of sea area and the highest in the Si(city) according to basic local municipality. The settlement amount related to the marine environment services was largest in the Gun(county). Further, there were significant differences between Gun(county) and the other regions(Si(city) and Gu(autonomous district)) with respect to most variables. The variables related to the estimated amount of fishery debris were the project purchasing salvaged debris generated while fishing and fishery waste disposal program in the post-response policies.