• Journal of Advanced Marine Engineering and Technology
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• v.38 no.7
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• pp.854-867
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• 2014

In the circumstance that high oil price state is continued over the world, the investment in crude oil development by oil major is a trend of increasing. Recently the number of delivered drill-ship for 5 years has been sharply increased all over the world and about twice than that of past 30 years. As addition to the increase of the drill-ship demand, the operation of drill-ships which is delivered recently is about 3,000 meters, ultra deep sea, on average and the work area is expending. Accordingly the drilling system including the size and length of pipe for drilling has been bigger and bigger and the power supply equipment for operation system also has large capacity. Unlike merchant vessel, high power and high voltage of diesel generators are required for drill-ship for which the demand for V-type 320 bore of diesel generator has increased. It is on the raised that the importance of lubrication oil cleaning for diesel generator on drill-ship which has longer time for construction, and also long term low load operation is unavoidable during commissioning of equipments. Recently it was reported that engine crankpin was damaged due to the hard contact caused by the abnormal wear down(Cam wear) on crankpin and bearing. The same pattern of wear down was found through the inspection on series vessels and the other vessel under commissioning. The purpose of this paper is to analyze of the wear mechanism based on the observation and theories and objective research from actual cases and to prepare the counter measures to avoid foreseeable damage when the lubricating oil is not properly cleaned.

• Journal of Preventive Medicine and Public Health
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• v.43 no.6
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• pp.535-542
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• 2010

Objectives: Exposure assessment is a major challenge faced by studies that evaluate the association between pesticide exposure and adverse health outcomes. The objective of this study was to investigate the reliability of information that farmers self-report regarding their pesticide use. Methods: Twenty five items based upon existing questionnaires were designed to focus on pesticide exposure. In 2009, a selfadministrated survey was conducted on two occasions four weeks apart among 205 farmers residing in Gyeonggi and Gangwon provinces. For a reliability measure, we calculated the percentage agreement, the kappa statistics and the intraclass correlation coefficient (ICC) between the two reports according to the characteristics of the subjects. Results: Agreement for ever-never use of any pesticide was 96.4% (kappa 0.61). For both 'years used' and 'age at the first use' of overall pesticides, high agreement was obtained (ICC: 0.88 and, 0.78, respectively), whereas those of 'days used' and 'hours used' were relatively low (ICC: 0.42 and, 0.66, respectively). The kappa value for the use of personal protective equipment ranged from 0.46 to 0.59, and hygiene activities came out at 0.19 to 0.37. The agreement for individual pesticide use ranged widely and there was relatively low agreement due to the low response rates. The reliability scores did not significantly vary according to gender, age, the education level, the types of crop or the years of farming. Conclusions: Our results support that carefully designed, self-reported information on ever-never pesticide use among farmers is reliable. However, the reliability of data on individual pesticide exposure may be unstable due to low response rates and needs to be refined.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.358-363
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• 1989

This experiment was carried out to analyze the effect of different air- and soil-temperatures on the major traits of barley including grain yield. Outdoor growth cabinet and soil temperature equipment were used for this study to control the air- and soil-temperatures during the plant growth. Earlier heading appeared at the higher soil-temperature under same air-temperature, and more stems showed when conbined with 25$^{\circ}C$ of air-temperature and l0$^{\circ}C$ soil-temperature than any treatment. There appeared, however, the longest spike length, awn length, distance from flag-leaf to spike and culm length at 20$^{\circ}C$ of air-temperature and 10$^{\circ}C$ or 15$^{\circ}C$ of soil-temperatures. As far as grain yields are concerned, there showed the highest yield on the condition combined with 20$^{\circ}C$ of air-temperature and 10$^{\circ}C$ of soil-temperature.

• The Journal of Engineering Geology
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• v.20 no.3
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• pp.257-269
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• 2010

We analyzed patent trends regarding stabilization technology for steep slope hazards, focusing on patents applied for and registered in Korea, the USA, Japan, and Europe. The technology was classified into four groups at the second classification step: prediction techniques, instrumentation techniques, countermeasure/reinforcement/mitigation techniques, and laboratory tests. A total of 2,134 patents were selected for the final effective analysis. As a result of portfolio analysis using the correlation between the number of patents and the applicant for each patent, the Korean and USA situations were classified as belonging to the developing period, and the Japanese and European situations were classified as belonging to the ebbing period. In particular, patent activity in Korea has been enlivened by government-led research. As a result of technology analysis at the second classification step, prediction techniques arising from Japan are evaluated as a competitive power technique, and laboratory tests arising from the USA are evaluated as a competitive power technique. However, prediction techniques and laboratory tests arising from Korea are evaluated as a blank technique. According to the prediction results regarding future research and developments, a new finite element analysis method and a numerical model should be established as part of prediction techniques, as well as sensors, and hazard prediction should be developed by integrating information and equipment using IT technology as part of instrumentation techniques. In addition, improvements to existing structures for erosion control and the development of new slope-reinforcement methods are required as part of countermeasure/reinforcement/mitigation techniques, and new laboratory apparatus and methods with an optimizing structure should be developed as part of laboratory tests.

• Journal of the Korean Institute of Gas
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• v.22 no.4
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• pp.32-38
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• 2018

The purpose of this study is to assess quantitatively the amount of leaks and the extent of dispersion in case of a leak at a hydrogen fluoride tank container unloading station, and to suggest a safety improvement plan to prevent recurrence of similar accidents. In 2012, Company H leaks 8 tonnes of tank containers with a maximum storage capacity of 18 Ton, causing it to become a social issue. As a result of calculation using Gaussian plume model, the concentration was estimated to be more than 20ppm from the leak point to 1,321 m radius. The leakage of hydrogen fluoride from the company R in 2014 was estimated to be 11.02 kg, of which 2.9 kg was treated by the scrubber. As a result of calculation using Gaussian plum model, the damage range with a concentration of 20ppm or more from the leak source was estimated to be 69 m in radius. As a result of comparing the above two accidents, it was found that the leakage amount was about 987 times different and the damaged site was more than 19 times different. Therefore, it was concluded that it was necessary to control the wearing of the protective equipment, the enclosure of the unloading site, the installation of the scrubber, and the emergency training to avoid the accidental leakage of a hydrogen fluoride from the unloading site.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.22-29
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• 2012

Robot related injuries in industrial accidents statistics during 2008~2010 have accounted for a total of 109 cases equivalent to 30~40 cases for each of those years. The number of injured compared to the dissemination of industrial robots(51,302 units/2004) can be regarded as quite low. However, the fatal injuries sustained by 7 (6.4%) out of 109 cases paints the stark reality of robot-related accident fatalities. It is a sad probability that as the automation process expands its use of industrial robots which have increased significantly in demand, the incidence of workplace accidents will also increase. Therefore, the incidence of accidents throughout the period of 2008~2010 has been analysed to prevent the injuries due to the increased use of industrial robots. In the analysis, the injuries occurred during the industrial robot operation accounted for 45.9% of the entire accidents. Thus, we examined the present status of the industrial robot operation to analyze the root cause of accidents occurred in our studied time period. We looked at a total of 469 workplaces. 456 workplaces responded in the year 2009 and survey studies were implemented at 13 of the 29 workplaces where work injuries were sustained in the year 2010. Even where protective measures and interlock devices were in place, our studies indicated that workers could access the robot area to perform the tasks in 188 sites(40.1%). Also, the 143 sites(30.5%) had control measures and equipment located in the safety fence. In addition, the robots found at 164 sites(35.0%) could be restarted without additional restarting operation. These three causes accounted for most of the workplace injuries during the industrial robot operations. Futhermore, we confirmed the fact that the protective measures of the current safety regulations were not strictly enforced. Based upon our studies and the investigation of the present status of the industrial robot operation, higher standards in training and supervision of workers in the robot operation must quickly be met in order to prevent these industrial injuries.

• Health Policy and Management
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• v.30 no.3
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• pp.326-334
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• 2020

Background: Korea has gradually expanded the coverage of medical care services in its national health insurance system. On April 1, 2018, it implemented a policy that expanded the coverage for an ultrasonography in the upper abdomen. In this study, we aimed to investigate the effect of the policy on the utilization of the ultrasonography in the upper abdomen in tertiary care hospitals. Methods: Using the dataset of the Health Insurance Review and Assessment Service, we explored changes in the utilization of the ultrasonography in the upper abdomen in tertiary care hospitals from July 1, 2017 to November 30, 2018 through the difference-in-difference (DID) mixed-effects-model method. Facility factor, equipment factor and personnel factors, type of hospital, the total amount of medical care expenses, and geographic region were considered as control variables. Results: On average, the utilization of the ultrasonography in the upper abdomen increased by 228% after the coverage expansion policy. However, the results of DID mixed-effects-model method analysis showed that the utilization increased by 73%. As for the number of beds, the utilization was higher with a group of 844-930, 931-1,217, and 1,218 or greater compared with a group of 843 or fewer, while the utilization of the number of ultrasonic devices was lower with a group of 45-49 compared with a group of 44 or fewer. The utilization decreased with the number of interns and the number of nurse assistants. Besides, relative to Seoul, the utilization was lower in the other metro-cities and provinces. Conclusion: The coverage expansion policy in the national health insurance system increased service utilization among people. Future research needs to investigate the degree to which such coverage expansion policy reduces the unmet medical care needs among the deprived in Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.262-269
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• 2020

Recently, many attempts have been made to reduce the time required for payment in various shopping environments. In addition, for the Fourth Industrial Revolution era, artificial intelligence is advancing, and Internet of Things (IoT) devices are becoming more compact and cheaper. So, by integrating these two technologies, access to building an unmanned environment to save people time has become easier. In this paper, we propose a smart shopping cart system based on low-cost IoT equipment and deep-learning object-detection technology. The proposed smart cart system consists of a camera for real-time product detection, an ultrasonic sensor that acts as a trigger, a weight sensor to determine whether a product is put into or taken out of the shopping cart, an application for smartphones that provides a user interface for a virtual shopping cart, and a deep learning server where learned product data are stored. Communication between each module is through Transmission Control Protocol/Internet Protocol, a Hypertext Transmission Protocol network, a You Only Look Once darknet library, and an object detection system used by the server to recognize products. The user can check a list of items put into the smart cart via the smartphone app, and can automatically pay for them. The smart cart system proposed in this paper can be applied to unmanned stores with high cost-effectiveness.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.689-697
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• 2020

Hazardous and noxious substances (HNS) may cause maritime incidents during marine transportation, which are liable to lead to a large amount of spillage or discharge into the sea. The damage to the marine environment caused by the HNS spill or discharge is known to be much greater than the damage caused by oil spill. Particularly dangerous is HNS, which is deposited or buried in the seabed, as it can damage the organisms that live on, in, and near the bottom of the sea, the so-called "benthos," forming the benthic ecosystem. Therefore, it is vital that the HNS deposited on the seabed be recovered. In order to do so, procedures and equipment are required for accurate detection, stabilization treatment, and recovery of HNS in subsea sediment. Thus, when developing a mechanical recovery system, the performance requirements should be selected using performance indices, and the conceptual design of the mechanical recovery system should be based on performance requirements decided upon and selected in advance. Therefore, this study was conducted to arrive at a conceptual design for a mechanical recovery system for the recovery of HNS deposited on the seabed. In the design of the system, based on the fundamental scenario, the method of suction foundation with the function of self enclosing was adopted for recovering the HNS sediment in the subsea sediment. The mechanical recovery system comprises the suction foundation, pollution prevention, a pump system, control system, monitoring device, location information device, transfer device, and tanks. This conceptual design is expected to be reflected and used in the basic design of the components and shapes of the mechanical recovery system.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.527-539
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• 2018

The subway used by many passengers is required to maintain a safe and comfortable environment and PSD (Platform Screen Door) must be installed in the platform after reinforcing the standard in 2003. In the previous research, in case of subway fire to control it, it is necessary to design the optimal ventilation and smoke exhaust system according to equipment capacity of the smoke exhaust system. Therefore, in this study, based on the results of previous research, three-dimensional numerical analysis was performed for the CO gas and smoke flow by the subway ventilation system in case of platform fire. As a result of this study, it was found that in case of emergency, if only the upper-level smoke exhaust system is activated, the risk of evacuation is high due to CO gas (653.8 ppm) and smoke concentration ($768.4mg/m^3$). And when all the smoke exhaust systems are activated and only the fire side PSD is opened, CO gas (36.0 ppm) and smoke concentration ($26.2mg/m^3$) are detected and the propagation range of smoke flow was reduced. When all the smoke exhaust systems are activated and only the fire side PSD is closed, it was analyzed as the most effective ventilation mode in the evacuation environment due to the absence of smoke-recirculation.