• Fire Science and Engineering
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• v.32 no.3
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• pp.76-87
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• 2018

This study describes the damage effects modeling for a quantitative prediction about the hazardous distances from pressurized chlorine saturated liquid tank, which has two-phase leakage. The heavy gas, chlorine is an accidental substance that is used as a raw material and intermediate in chemical plants. Based on the evaluation method for damage prediction and accident effects assessment models, the operating conditions were set as the standard conditions to reveal the optimal variables on an accident due to the leakage of a liquid chlorine storage vessel. A model of the atmospheric diffusion model, ALOHA (V5.4.4) developed by USEPA and NOAA, which is used for a risk assessment of Off-site Risk Assessment (ORA), was used. The Yeosu National Industrial Complex is designated as a model site, which manufactures and handles large quantities of chemical substances. Weather-related variables and process variables for each scenario need to be modelled to derive the characteristics of leakage accidents. The estimated levels of concern (LOC) were calculated based on the Gaussian diffusion model. As a result of ALOHA modeling, the hazardous distance due to chlorine diffusion increased with increasing air temperature and the wind speed decreased and the atmospheric stability was stabilized.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.613-616
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• 2009

Information present condition is using situation board by manual processing that is consisted of ship arrangement plan and letterpress and magnet etc. in Pyeongtaekhang's deep-sea fishing vessel company. Study that mark open sea far from land ship information of underway 37 ships that is accepted in every time in internet web application environment that is based on Ubiquitous Network in PC that is linked to internet. 3 through practical use of RIA of Flash technology base compose Digital Dash-Board in width grid structure only and do ship sailing addition that is operating in 6 oceans and latitude, hardness indication as well as various informations to do visual display do. Emphasized in dynamic Web Application construction because can heighten the convenience to operator and user, and take advantage of real time data.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.62-70
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• 2019

The APR1400 reactor may be operated for a long time under high temperature and pressure conditions, causing damage to the stud holes and causing stud bolts and holes to stick. The present practice is to manually remove the anti-sticking agent and foreign matter remaining in the APR1400 reactor stud hole and to visually check the surface condition of the thread to check the damage status of the threads. In the case of the APR1400 reactor stud holes, manually cleaning the threads increases the risk of radiation exposure and operator's fatigue. To avoid this, the autonomous mobile robot is used to automatically clean the reactor stud holes. The purpose of this study is to optimize the cleaning performance of the mobile robot by looking at the behavior of the surface roughness of the stud surface cleaned by the brush attached to the mobile robot due to changes in brush material, thickness of wire, and rotation speed. A microscopic approach to the surface roughness of the flank is needed to investigate the effects of the newly proposed brush of the autonomous mobile robot on the thread holes. According to this experiment, it is reasonable to use STS brush rather than Carbon one. Optimal operating conditions are derived and the safety of APR1400 reactor stud holes maintenance can be improved.

• Fire Science and Engineering
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• v.32 no.6
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• pp.126-133
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• 2018

Korea has been preparing and operating crisis management standardized manuals so that over 30 disaster types that need to be managed at the national level can be selected and systematically managed. This study analyzed the crisis alert levels of two standard manuals related to the case with reference to the contents of the Framework Act on the Management of Disaster and Safety and National Crisis Management Basic Guidelines. According to the Act and Guidelines, crisis alerts are issued before a crisis or disaster, but the criteria of crisis alerts of the two manuals showed that the national crisis had already occurred and the disaster occurred due to a marine vessel accident at the serious level. In addition, the results of timing of issuance of crisis alert were reviewed. If the signs can be identified, a crisis alert may be issued prior to the occurrence of the incident, but a crisis alert cannot be issued when an incident occurs without a sign. In the case of an incident where there are no signs, but there is a possibility of spreading to a national level disaster, the disaster management supervision agency could issue a crisis alert.

• Journal of Yeungnam Medical Science
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• v.36 no.3
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• pp.231-240
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• 2019

Background: We sought to determine the value of combining diffusion-weighted (DW) and perfusion-weighted (PW) sequences with a conventional magnetic resonance (MR) sequence to assess solid components of borderline ovarian tumors (BOTs) and stage I carcinomas. Methods: Conventional, DW, and PW sequences in the tumor imaging studies of 70 patients (BOTs, n=38; stage I carcinomas, n=32) who underwent surgery with pathologic correlation were assessed. Two independent radiologists calculated the parameters apparent diffusion coefficient (ADC), $K^{trans}$ (vessel permeability), and $V_e$ (cell density) for the solid components. The distribution on conventional MR sequence and mean, standard deviation, and 95% confidence interval of each DW and PW parameter were calculated. The inter-observer agreement among the two radiologists was assessed. Area under the receiver operating characteristic curve (AUC) and multivariate logistic regression were performed to compare the effectiveness of DW and PW sequences for average values and to characterize the diagnostic performance of combined DW and PW sequences. Results: There were excellent agreements for DW and PW parameters between radiologists. The distributions of ADC, $K^{trans}$, and $V_e$ values were significantly different between BOTs and stage I carcinomas, yielding AUCs of 0.58 and 0.68, 0.78 and 0.82, and 0.70 and 0.72, respectively, with ADC yielding the lowest diagnostic performance. The AUCs of the DW, PW, and combined PW and DW sequences were $0.71{\pm}0.05$, $0.80{\pm}0.05$, and $0.85{\pm}0.05$, respectively. Conclusion: Combining PW and DW sequences to a conventional sequence potentially improves the diagnostic accuracy in the differentiation of BOTs and stage I carcinomas.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.11
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• pp.1-7
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• 2020

Recently, hydrogen has gained considerable attention as an eco-friendly fuel, which helps in reducing carbon dioxide content. Specifically, there is a growing interest in vehicles powered by a hydrogen fuel cell, which is spotlighted as an environmental-friendly alternative. A hydrogen transport system, fuel cell system, fuel supply system, power management system, and hydrogen storage system are key parts of a hydrogen fuel cell truck. In this study, a hydrogen storage system is built and analyzed. The expansion length of the storage vessel at maximum operating pressure (87.5 MPa) was calculated with ABAQUS, and then the optimized system was designed and built. The leak and bubble tests were performed on the built storage system. The leakage of the system was measured to be under 5 cc/hr. Hence, it can be used as a research test for the safety evaluation of leading systems of hydrogen fuel-powered commercial vehicles.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.235-243
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• 2022

A total of 97,623 ships were registered in Korea in 2019. Among these, 65,835 vessels, accounting for approximately 67 % of the total number of ships, were registered as fishing vessels. As with the proportion of fishing vessels, the frequency of marine accidents is also high. In 2020, 2,331 of 3,535 accidents occurred on fishing vessels. Hence, various institutional arrangements are required for improving the safety of domestic fishing vessels. In this study, we examined domestic and international regulations on domestic and foreign control performance related to fishing boats for improving the safety of fishing boats. Additionally, the ratio of the rudder area of 153 fishing boats operating in Korea was investigated to examine the current status of the rudder area design of fishing boats whose design standards have not been clearly established compared to fishing boats. Resultantly, we statistically confirmed that most fishing boats were designing rudder areas because they did not meet international standards. In the future, these analysis results can be used as basic data to prepare rudder area design standards for improving the maneuvering performance of domestic fishing boats.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.3
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• pp.175-181
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• 2021

This study describes the model tests in ice according to the frictional coefficient of an ice-breaking ship and the change in ice resistance by the analysis method for each component of ice resistances. The target vessel is a 90K DWT ice-breaking tanker capable of operating in ARC7 ice conditions in the Arctic Ocean, and twin POD propellers are fitted. The hull was specially painted with four different frictional coefficients on the same ship model. The total ice resistance can be separated by ice breaking, ice buoyancy, ice clearing resistances through the tests in level ice, pre-sawn ice and creep test in pre-sawn ice under sea ice thickness of 1.2 m and 1.7 m. Ice resistance was analyzed by correcting the thickness and bending strength of model ice by the ITTC correction method. As the frictional coefficient between the hull and ice increases, ice buoyancy and clearing resistances increase significantly. When the surface of the hull is rough, it is considered that the broken ice pieces do not slip easily to the side, resulting in an increase in ice buoyancy resistance. Also, the frictional coefficient was found to have a great influence on the ice clearing resistance as the ice thickness became thicker.

• Journal of Trauma and Injury
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• v.35 no.2
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• pp.123-127
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• 2022

Iatrogenic vascular injury (IVI) can occur with any technique or type of surgery performed around a blood vessel. Patients with severe trauma are at risk of IVI. In this study, we describe our experiences of IVI in the trauma field. We reviewed five patients who were diagnosed with an IVI and received either surgical or endovascular treatment. Of the five patients, one had an arterial injury, three had venous injuries, and one had an arteriovenous fistula, a form of combined arterial and venous injuries. Of the five patients, four had undergone orthopedic surgery. The IVIs of three patients were immediately identified in the operating room and simultaneous vascular repair was performed. The remaining one patient underwent additional surgery for occlusion related to entrapment of the superficial femoral artery by a surgical wire used during orthopedic surgery. Complications presumably related to the IVI were identified in two patients. IVI in trauma patients can be successfully managed, but significant morbidity can occur. If an IVI is suspected, immediate evaluation and management are required.

• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.877-883
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• 2023

For safe operation of ships and management of marine fisheries farms, the data set that extracts the boundaries of marine fisheries farms can provide information on obstacles in the vessel's navigation path in advance by examining whether it matches the fishing ground permit area. In addition, it can be used to determine whether fish farms are operating to compensate for damage caused by marine accidents, and the relevant local government can use it to manage fishing grounds. It is also highly utilized as basic data to identify obstacles for safe navigation of ships. In this study, Sentinel-2 satellite image data from the European Space Agency (ESA) was used to extract the boundaries of fish farms. From the video image, the fish farm's status data by cycle was divided into five zones: Busan-Ulsan area, Geoje-Changwon area, Goseong-Tongyeong area, and Namhae-Sacheon area. Through the image highlighting process, the farm boundary data and meta data were processed and extracted.