• Journal of the Korean Institute of Gas
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• v.15 no.2
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• pp.33-39
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• 2011

This study presented quantitative risk analysis in case of transporting explosive materials by railway. Accident types were classified into accidents of in station and in transit. And the study presented an initial value of accident frequency through derailment accident and crushing one according to each type, and drew the results of accident frequency through event tree analysis. Damage impact evaluation used TNT equivalent method and probit analysis method. As the result of risk evaluation, railway transportation of explosive materials passing through areas which are high in population density is appeared to be able to cause a large number of personnel injury when occurring accidents. Specially, the accident of explosive transportation combined with petroleum was forecasted as easily resulting in large explosive accident. Consequently, there is a necessity to reduce consequences by decreasing passage through areas where are high in population density, and take measures for lessening the risks in case of transporting dangerous explosive materials.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.507-513
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• 2021

This study examined the final stop position and posture of both vehicles, the damaged part of the vehicle, the road surface, the specifications of the vehicle, and the angle of impact, centering on the case of a collision in which no surface trace was found. As a result of the simulation, the impact velocity of an SM5 and Lexus was 131 km/h and 74 km/h, respectively, and the impact angle of the SM5 and Lexus was 0.91° and -161.07°, respectively. The cause of the accident was that the SM5 passed through the intersection exceeding the maximum speed limit of 61 km/h and entered the Lexus' left turn lane. Lexus collided during the evacuation to avoid the collision. The collision trajectory error rate of the simulation was approximately 1.4%. Of the subjective experience of accident investigators, the collision dynamics and vehicle engineering aspects and simulations were actively utilized to provide close-to-fact cause identification.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.424-430
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• 2021

Determining the cause of a traffic signal violation is difficult if the drivers' claims are contradictory. In this study, the process of identifying signal violations using a simulation was presented based on cases. First, statements from the driver or witness whose cause of the signal violation is unclear were excluded. Second, the final position, final location, damaged area, steering status, braking status, and road surface traces of the vehicle were collected. The impact point was investigated from the stop line. Third, simulation data were modified and entered until the collision situation of the accident vehicle and the final stop position were met. Fourth, if the simulation results were consistent with the crash situation, the facts were verified by cross-validation to conform to the driver's statement. The results of the simulation showed that the Lexus entered the left turn signal in the intersection at approximately 55 km/h. In comparison, the Sonata driver saw the vehicle straight ahead at the intersection, entered the 72 km/h intersection, and collided with the Lexus. Therefore, the Sonata was identified as a signal violation, and the claims of the Sonata driver, witnesses, and police were contradictory.

• International Journal of Highway Engineering
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• v.10 no.1
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• pp.31-39
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• 2008

Preventing the traffic accident by accurately predicting it in advance can greatly improve road traffic safety. The accurate traffic accident prediction model requires not only understanding of the factors that cause the accident but also having the transferability of the model. So, this paper suggest the traffic accident diagram using CART(Classification And Regression Tree) analysis, developed Model is compared with the existing accident prediction models in order to test the goodness of fit. The results of this study are summarized below. First, traffic accident prediction model using CART analysis is developed. Second, distance(D), pedestrian shoulder(m) and traffic volume among the geometrical factors are the most influential to the traffic accident. Third. CART analysis model show high predictability in comparative analysis between models. This study suggest the basic ideas to evaluate the investment priority for the road design and improvement projects of the traffic accident blackspots.

• Fire Science and Engineering
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• v.34 no.2
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• pp.86-93
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• 2020

This study aims to maintain the safety of an outdoor storage tank through the fundamental case analysis of explosion and fire accidents in the storage tank. We consider an accident caused by the explosion of fire inside the tank, as a result of the gradual spreading of the residual fire generated by wind lamps flying off a workplace in the storage tank yard. To determine the cause of the accident, atmospheric diffusion conditions were derived through CCTV image analysis, and the wind direction was analyzed using computational fluid dynamics. Additionally, the amount of oil vapor inside the tank when the floating roof was at the lowest position, and the behavior of the vapor inside the tank when the floating roof was at the highest position were investigated. If the cause of the explosion in the storage tank is identified and the level of the storage tank is maintained below the internal floating roof, dangerous liquid fills the storage tank, and the vapor in the space may stagnate on the internal floating roof. We intend to improve the operation procedure such that the level of the storage tank is not under the Pontoon support, as well as provide measures to prevent flames from entering the storage tank by installing a flame arrester in the open vent of the tank.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.351-357
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• 2019

This research was performed to propose domestic standard for design and management of flexible hose by analyzing chlorine leak caused by breakage of the hose in Ulsan, 2018. The leak had multiple causes but this paper focuses on analyzing the cause of breakage of flexible hose, the direct cause. According to the analysis, flexible hose that the company of the accident used for chlorine transfer was inappropriate in several aspects including material and wall thickness. And even pressure test had been conducted below operating pressure. Upon investigation on five companies that handle chlorine in Ulsan, four companies were using inappropriate flexible hose for chlorine transfer. Since there is no domestic standard for the design of flexible hose for chlorine transfer at present, it is hard to examine its design adequacy. Design standard of flexible hose used in chlorine transfer that is applicable domestically is proposed based on this research. It will contribute to the reduction in risk of breakage of the hose if the proposed standard could be applied in design and examination of flexible hose.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.552-555
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• 2004

As the scale of building construction is larger and more complex, accident is increasing on the steel structure work process. But Safety-Inspection has been carried out through many other checklists in the workplace, it hasn't been used actively. Because checklist wasn't written at the level of specific work and applied scope is Insufficient. So, we must grasp accidental cause about detailed work for making safety management checklist accurately. For this study, we are confining a range to steel structure work of all the building construction. We will classify steel structure process into the detailed work for preventing accident. And we will grasp accidental cause about detailed work for developing the checklist in the future.

• Journal of Biosystems Engineering
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• v.5 no.2
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• pp.58-66
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• 1980

A survey was conducted to investigate the power tiller accidents. Eight provinces were covered for this study, and 278 power tiller owners were selected randomly by computer random generator. The results are summarized as follows : A. Frequency of accident. (1) Each power tiller had an accident 0.98 times a year and once every 361 hours of use. Higher frequency of accident was found during the miscellaneous operations including the preparation for farming operation, and there was one accident for every 92 hours of use. (2) The power tiller, which are more than six years old, met an accident 1.19 times a year , or one every 311 hours of use. This value was the highest one compared with any other group. (3) Kerosene engine power tillers met an accident 0.97 times a year, or one every 389 hours of use. It was one tie a year, or once every 329 hours of use for diesel engine power tillers. (4) Among diesel-engine power tillers, 10 horse-power group showed a higher frequency tillers. B. Cause of accident (1) The accidents of power tiller were mainly of sefety , which occurred due to the lack of attention during the operation and 47.4% of the total accidents. The next was of accidental, which represented 26.3% of the total accidents. (2) High percentage of safety accidents occurred during the preparation for farming operation including adjustment. Most of the accidental accidents occurred during the transportation. (3) Lower frequency of accident was found in the power tiller group which were operated by the 21-40 years old operator in comparison with that of the power tiller which was operated by other age group. Power tillers which were operated by high school graduates experienced less accidents compared to other education levels. C. Damage by accident (1) Eighty seven pescents of the total accidents caused damage to the power tiller operator , and 13 % of the total accidents caused property damage only. (2) With regard to the damage to the power tiller operator, 73.8% of the total accidents caused light injury but 26.3% caused heavy injury. (3) Accidents which occurred during machine preparation , and farming operations caused minor injury to the operator, but the accidents during transportation caused heavy injury which cost more than 15 days for recovery. (4) Among the 39 accidents , which caused property damage 18 accidents were from the transportation . Among the total property damage accidents 53.8% were light one which cost only less than 1,000 won. (5) The property damage from each accident cost 1,017 won, on the average, with regard to the kinds of operation, the highest property damage occurred during transportation work, with the value of 2, 965won.

• Journal of Fisheries and Marine Sciences Education
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• v.25 no.3
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• pp.716-723
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• 2013

The postal or group questionnaire survey was conducted to inquire into the cause of collision between fishing vessel and non-fishing vessel targeting fishing vessel personnel(FVP), non-NFVP and a person involved in a marine accident. As a result, we could verify the root cause of collision, a negligence of lookout which noted overwork for FVP and careless for non-FVP. The cause of collision by inappropriate avoid action was poor communications for FVP and non-FVP. To reduce collision, we need to be trained to take a sharp lookout, a radio communication by VHF and the collision avoidance actions by early and substantial action to keep well clear. The results are expected to contribute for the reduction of collision and victims.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1274-1279
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• 2011

The purpose of this paper is to present the manufacturing defect and damage pattern of a 3 phase 22.9/3.3kV oil immersed transformer, as well as to present an objective basis for the prevention of a similar accident and to secure data for the settlement of PL related disputes. It was found that in order to prevent the occurrence of accidents to transformers, insulating oil analysis, thermal image measurement, and corona discharge diagnosis, etc., were performed by establishing relevant regulation. The result of analysis performed on the external appearance of a transformer to which an accident occurred, the internal insulation resistance and protection system, etc., showed that most of the analysis items were judged to be acceptable. However, it was found that the insulation characteristics between the primary winding and the enclosure, those between the ground and the secondary winding, and those between the primary and secondary windings were inappropriate due to an insulating oil leak caused by damage to the pressure relief valve. From the analysis of the acidity values measured over the past 5 years, it is thought that an increase in carbon dioxide (CO2) caused an increase in the temperature inside the transformer and the increase in the ethylene gas increased the possibility of ignition. Even though 17 years have passed since the transformer was installed, it was found that the system's design, manufacture, maintenance and management have been performed well and the insulating paper was in good condition, and that there was no trace of public access or vandalism. However, in the case of transformers to which accidents have occurred, a melted area between the upper and the intermediate bobbins of the W-phase secondary winding as well as between its intermediate and lower bobbins. It can be seen that a V-pattern was formed at the carbonized area of the transformer and that the depth of the carbonization is deeper at the upper side than the lower side. In addition, it was found that physical bending and deformation occurred inside the secondary winding due to non-uniform pressure while performing transformer winding work. Therefore, since it is obvious that the accident occurred due to a manufacturing defect (winding work defect), it is thought that the manufacturer of the transformer is responsible for the accident and that it is lawful for the manufacture to investigate and prove the concrete cause of the accident according to the Product Liability Law (PLL).