• Journal of Korean Society of Transportation
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• v.26 no.2
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• pp.47-56
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• 2008

Two-Lane Highway of Korea is important, Because it has the largeest portion of all roads of Korea. But it has only one lane for one direction. So, If Delays are happened by low-speed vehicles, high-speed vehicles should over-take through the other side of the road. This over-takings can generate the high possibility of traffic accidents and the severity of traffic accidents by over-takings is very high. Because it generates a head-on collision. But the level of Service that indicates the operation states of Two-Lane Highway is defined as a conception that explains the operation conditions of traffic safety etc. Whencalculating the Level of service. It is considered by only delays. So, in this paper, first, this author wants to present the calculation of delay-time by Total-Delay Rate. Second, by multiplying this delay-time by the costs of delays wants to present the method of calulates the total delay costs. Third, to consider the traffic accidents, After predicting the number of traffic accidents, As multipling this by the average of costs of traffic accidents. want to present the method to calculate Total traffic accidents costs. Forth, present the operation costs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.69-74
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• 2018

With the increasing development of industrial society and the availability of high quality electrical energy, the simplification of operation and maintenance procedures is required, in order to ensure the reliability and safety of electrical systems. In this paper, the dielectric breakdown characteristics of $N_2-O_2$ mixed gas solid insulation, which is used as an alternative to SF6 in various electric power facilities, are verified. When the gas mixture has a composition ratio similar to that of the atmosphere, the dielectric breakdown characteristics are relatively stabilized. It was confirmed that the breakdown voltage of the gas in the electrode near an equal electric field increased with increasing pressure according to Paschen's rule. The breakdown voltage of the surface increased linearly with increasing pressure, and the difference was caused by the mixing ratio of $O_2$ gas. This change in the surface insulation breakdown voltage was caused by the influence of the electrically negative $O_2$ gas and the intermolecular collision distance. In this study, the influence of the intermolecular impact distance was larger (than that in the absence of the electrically negative $O_2$ gas). The breakdown voltage relation applicable to Teflon according to the surface insulation characteristics was calculated. The characteristics of the surface insulation properties of Teflon, which is used as a solid insulation material, were derived as a function of pressure. It is thought that these results can be used as the basic data for the insulation design of electric power facilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.469-475
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• 2010

The railway signalling system plays an essential role in the safe and efficient train operation as serving control functions of train operation intervals and train routes. The reliability and safety of the system are very important because the failure of the railway signalling system can lead to train collision or derailment as well as train operation stop. Until now, in railway signalling system the conventional wayside signal mode has been used generally. There are, however, the risk of accidents such as human mistakes caused by that the driver identifies the signal lamp status and controls train speed with the naked eye. It is also necessary to refurbish the obsolete system. Thereby, It is being effective that the onboard signal mode has been recently introduced and applied in order to transmit the speed control information to train by using the computer and communication equipment. It is necessary to switch over the system in a way while providing passengers with an operation service to replace the obsolete signal system. In this paper, we verify the cases through trial assessment which are solved by the way of adding specific functionalities in the problems of interference among the procedure of switch-over processes and a serial of processes for system verification while a train is operated in the new system in parallel to the existing system.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.35-44
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• 2003

Considering possible legal and policy problems with regard to the Cheju Strait, a central issue is whether the Cheju Strait should be treated as Korean territorial sea or an international strait The claim that the strait is territorial sea has been based on the use of a straight baseline method of dermarcation With the use of straight baseline, Korea claims that the breadth of the Cheju Strait is only 20.7 miles at its narrowest point and therefore the strait becomes the territorial sea of Korea. The consideration cf marine pollution has weighed heavily in claiming the Cheju Strait as territorial sea. Pollution resulting from the accidents cf tankers caused by fire, collision, or stranding in the Cheju Strait and the Korea Strait would be enormous, affecting the entire coastal waters of the south coasts cf Korea's mainland and Japan's Tsushima Islands areas. Catastrophic pollution in the Cheju Strait could also come from the accidents cf large-size oil tankers passing through the Korea Strait from the Malacca Strait Although the Korean government considers the geographic and socioeconomic conditions sufficient to justify Korea's claim of the Cheju Strait as territorial sea, it believes that declaring it so would raise considerable legal conflicts with maritime states. In view of the legal difficulties and the need to meet the problems arising from the growing vessel traffic in the Cheju Strait, the sea lanes and traffic separation schemes may be considered an alternative to the internationalization of the Cheju Strait Even if the Korean government dose not do so, the regime of innocent passage should be applied to vessels passing through the Strait and should not suspend innocent passage through the Strait. Therefore, the Korean government needs to have a more legal, pragmatic, functional and managerial approach than a purely sovereign and selfish approach to the solution of legal matters of the Cheju strait For this purpose, the UN Convention on the Law of the Sea would serve as a guide and also self-restraint and cooperative approaches would become norms governing the resolution of the law of the sea issues in the Cheju Strait.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.369-376
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• 2019

Ship hydrodynamics in the confined waterways is challenging. When a ship is maneuvering in confined waterways, the hydrodynamic behavior may vary significantly because of the hydrodynamic interaction between the bottom of the ship hull and the seabed, or so-called shallow water effects. Thus, an accurate prediction of shallow water and bank effects is essential to minimizing the risk of the collision and the grounding of the ships. The hydrodynamic derivatives measured by the virtual captive model test provide a path to predicting the change in ship maneuverability. This paper presents a numerical simulation of captive model tests to predict the maneuverability of a ship in confined waterways. Also, straight and zig-zag simulation were conducted to predict the trajectory of a ship maneuvering in confined waterways. The results showed that the asymmetric flow around a ship induced by vicinity of banks causes pressure differences between the port and starboard sides and the trajectory of a ship maneuvering in confined waterways.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.5
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• pp.1069-1076
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• 2017

C-ITS(Cooperative-Intelligent Transportation System) provides services that require strict real-time such as forward collision warning, road safety service and emergency stop. WAVE(Wireless Access in Vehicular Environments), a core technology of C-ITS, is a technology designed for high-speed driving. However, in order to provide stable communication service by applying to real road environment, various performance tests of real vehicular environment are required. In the real road environment, WAVE communication performance is influenced by the surrounding environment such as moving vehicle, road shape and topography. Especially, when the vehicle is moving at high speed, the traveling position according to the speed of the vehicle, The surrounding environment changes rapidly. Such changes are factors affecting the communication performance, therefore a system and methods for analyzing them are needed. In this paper, we propose the configuration and test method of an effective performance evaluation system under high-speed driving and describe the results of analyzing the communication performance based on the data measured through the actual vehicle test.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.83-95
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• 2018

With recent technological advances in the shipbuilding industry, vessels have been improved in size and performance. As a result, an accident such as grounding, caused by a single ship-to-ship collision, could lead to a large-scale maritime disaster. Considering the seriousness of the situation, the international community has been consistently updating the standards for Electronic Navigational Chart(ENC) to improve the maritime safety. S-57, the existing ENC standard governed by the International Hydrographic Organization(IHO), includes standards for generating conventional binary-type ENC data sets. The S-57 standard, however, has not been updated since the release of Version 3.1 in December 2000. Since then, the standard has failed to reflect technological development regarding maritime spacial information, which has been consistently improving. In an effort to address this concern, the IHO designated S-100, i.e., the next-generation ENC production standard. S-100 differs from S-57 in data exchange type. Contrary to the conventional ENC standards, which use binary-type data, S-10X, based on the next-generation ENC standards, uses ENC data composed of Feature Catalogue, Portrayal Catalogue, and GML. Considering this fact, it is necessary to update S-58, the ENC validation check standard, or designate a new standard for ENC validation checks. This study is developed own software to implement validation checks for new types of data, and identified improvement points based on the test results.

• Journal of Trauma and Injury
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• v.22 no.1
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• pp.51-56
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• 2009

Purpose: The purpose of this study was to investigate environmental factors contributing to childhood home slip-down injuries. Methods: Among a total of 2,812 injured children in our Customer Injury Surveillance System (CISS), we performed a prospective study on 262 children with home slip-down injuries who visited the pediatric emergency department of Asan Medical Center between March 2008 and February 2009. We made a frequency analysis on parameters such as activities just before the accident, the presence of any obstacles or lubricant materials, specific home place in the home where the injuries occurred, flooring materials on which the slip-down happened, additional objects hit after slip down, the site and kind of injury, the duration of therapy, and the disposition. Results: Walking was the most common activity just before the injury. Because rooms and bathrooms were most common places in the home for slip down injuries, laminated papers/ vinyl floor coverings and tiles were the most common flooring materials used in the places where the injuries occured. Most commonly, no obstacles caused the children to slip down, but the furniture, stairs, doorsills, wetness, or soapy fluid followed after that. Over half of the children who slipped (58%) also collided with other than the floor itself after the slip-down, most common objects hit were the edges of the furniture, and doorsills, followed by stairways. The head and neck were the most commonly injured sites, and a laceration was the most common kind of injury. Most children needed less than 1 week of therapy, only 4 children (1.53%) admitted. There were no mortalities. Conclusion: The environmental factors contributing to slip-down injuries were the bathroom, laminated papers/vinyl floors, the furniture, stairs, doorsills, and wetness or soapy fluid. Especially, the furniture, stairs, and doorsills can be both primary obstacles and secondary collision objects. For the safety of our children, we must consider these factors on housing, when decorating or remodeling our house.

• The Korean Journal of Air & Space Law and Policy
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• v.1
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• pp.163-191
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• 1989

The accident of the midair collision, passengers' falling or goods' dropping occurs or supersonic aircraft make a sonic boom during their conveying passengers or goods to the destination. The accident in transmit damages the their parties on the surface or their properties. In these cases, the third parties who were harmed to their lives or properties have the right to claim damages against the air carrier who caused them. These matters have become one of the important things since aircraft conveyed passengers and goods. Therefore, it is a great concern to settle these matters by law. But the Safety of the present aircraft has been much increased and the aircraft have become larger in size. Its flight altitude became higher than before. So the relationship of the aircraft to the third parties is much different from that of the earlier aircraft. The air transport is now indispensable to our life. It is not so easy to control these matters. In the early part of 20th century, when the third parties suffered the damage, many European countries made laws on the basis of the principle of liability without fault. But each country had a variety of its own law, and different kinds of difficulties have been brought about. Accordingly, the Rome Convention on Surface Damage (1933, 1952, 1978) has been made and revised. In spite of being revised, it contains many problems, and is not carried into effect world-wide. On the other hand, there are no regulations about the compensation of the third parties damaged in Korean existing laws. In case the damage is brought about to them, it is obviously true that the settlement of the liability of compensation for damage should be made by the general principle on the tort in domestic laws. At this point, it is urgent that we make a special law though the domestic legislation as a preliminary measure before we sign the international convention to save third damaged. It is desirable that we should, for the responsibility of the air carriage for the demage of the third parties on the surface, bring in the theory of the absolute liability in view of the legislation of many conutries. As the aircraft fly in the sky, their flight always contains some danger. It is very difficult to prove the fault, and the operator should suffer the principle of liability without fault or the similiar one. In case the liability without fault will be imposed upon the operator for the damage of the third parties, it is necessary to bring in the liability protection system for the protection and up upbringing of the air carriage. The Burden of danger of the air carriage will be reduced by introducing the system. A domestic legislation measure should be necessarily taken as soon as possible as a legal security measure on these matters.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.445-450
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• 2017

It is necessary to set a route to reflect the traffic flow for the safety of the traffic vessels. This ongoing analysis is needed to ensure that the vessels comply with a route. The purpose of this study is to discover the problems of the recommended route vicinity for Wando Harbor and suggest an improvement plan. We used a support vector machine based on the ship's trajectory to establish an efficient route center line. Since the vessels should navigate to the starboard side, with reference to the center line of the recommended route, the trajectories of the vessels were divided into two clusters. The support vector machine is being used in many fields such as pattern recognition, and it is effective for this binary classification. As a result of this study, about 79.5 % of the merchant eastbound ships in a 2.4 NM distance to Jangjuk Sudo did not observe the recommended route, so the risk of collision always existed. The contraflow traffic rate of the route of the eastbound ships decreased from 79.5 % to 30.9 % when the recommended route was reset about 300 meters to the north, from its present position. The support vector machine applied in this study is expected to be applicable, to effectively set the route center line because the ship trajectories can be classified into two clusters.