• Journal of Power System Engineering
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• v.21 no.4
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• pp.70-76
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• 2017

This paper presents the development of a Gas Valve Train (GVT) control system which is the core equipment of LNG fueled vessels. Due to the increasing worldwide demand for echo friendly green ship products, domestic companies urgently require to develop a core equipments for the LNG fueled vessels to secure worldwide markets in marine engineering. A LNG fueled engine generally equips the GVT, a fuel supply system that steadily supplies clean high-pressure LNG to the engine. The GVT requires a safety operational control system that can prevent any gas leakage accident, and a system that monitors operation status in real time. Therefore, we introduces a development for GVT control and monitoring system design and the design was systematically performed by means of functional analysis and differentiation of foreign advanced products.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1781-1791
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• 2016

This study aimed to analyze the economic effectiveness on environment improvement project that has been implemented in five fishing grounds of Taean-gun which had been damaged by the Hebei Spirit oil spill accident. In the analysis, first, this study performed the survey on residents perceptions about the environment improvement project. Second, the cost-benefit analysis was carried out to evaluate the economic effectiveness of the project. The survey results of residents perceptions indicated that the damage of oil spill was considerable in the target areas. It also showed that residents wanted to continue the environment improvement project and the levels of project satisfaction were quitely high. The economic results showed that 3 areas(Woong-do, Wang-san, and Dang-mi) would have positive values of NPV and B/C ratio, but the other(Nu-dong) would have negative values. The findings of this analysis could be used as the base data for increasing operational efficiency of future environment improvement projects.

• Journal of Korean Institute of Industrial Engineers
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• v.41 no.5
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• pp.499-510
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• 2015

The purpose of this research is to identify new service opportunities for enhancing driving safety of intra-city buses based on driving behavior analysis. Service opportunity identification involves finding target customers of service (to whom), motivations for service (why), service contents (what), and service delivery process (when, where). This paper presents an analysis of driving behaviors using the operational data of intra-city buses in conjunction with traffic accident data and drivers' driving history data. This paper also presents four identified service opportunities based on the data analysis results. This research would contribute to enhancing driving safety of intra-city buses in Korea and serve as a basis for developing new services for driving safety enhancement.

• International Journal of Highway Engineering
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• v.10 no.2
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• pp.35-45
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• 2008

Trucking is the most frequently used mode for freight movement due to relatively lower shipping costs and its operational flexibility. However, truck traffic can contribute to serious safety problems where they occupy high percentage of the total traffic. Heavy truck crashes arc more likely to result in serious injuries and fatalities than are crashes involving light vehicles. Therefore, safety issues for truck traffic are very significant both for public agencies and for general travelers. The objective of our study is to find truck-involved accident patterns according to traffic conditions and main factors as well as to find the most critical factor through conventional statistical techniques. A vailable data were obtained from TASAS (Traffic Accident Surveillance and Analysis System). Once critical factors are identified, effective and efficient truck management strategies can be discussed.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.7-12
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• 2022

The main cause of cable accidents is the accelerated deterioration of the cable itself or internal and external electrical, mechanical, chemical, thermal, moisture intrusion, etc., which reduces insulation performance and causes insulation breakdown, leading to cable accidents. Insulation deterioration can occur even when there is no change in the appearance of the cable, so there is a difficulty in preventing cable accidents due to insulation deterioration. Since cable accidents can occur in areas with poor insulation due to the effects of overvoltage and overcurrent, it is necessary to comprehensively analyze transformers and circuit breakers, and ground faults caused by phase-to-phase imbalance. Ground fault accidents due to insulation breakdown of cables can occur due to defects in the cable itself and poor cable construction, as well as operational influences, arcs during operation of electrical equipment (switchers, circuit breakers, etc.). analysis is needed. This study intends to examine the causes of cable accidents through analysis of cable accidents that occurred in a manufacturing factory.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.105-115
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• 2002

For many rears, traffic accident statistics are the most direct measure of safety for a signalized intersection. However it takes more than 2 or 3 yearn to collect certain accident data for adequate sample sizes. And the accident data itself is unreliable because of the difference between accident data recorded and accident that is actually occurred. Therefore, it is rather difficult to evaluate safety for a intersection by using accident data. For these reasons, traffic conflict technique(TCT) was developed as a buick and accurate counter-measure of safety for a intersection. However, the collected conflict data is not always reliable because there is absence of clear criteria for conflict. This study developed objective and accurate conflict criteria, which is shown below based on traffic engineering theory. Frist, the rear-end conflict is regarded, when the following vehicle takes evasive maneuver against the first vehicle within a certain distance, according to car-following theory. Second, lane-change conflict is regarded when the following vehicle takes evasive maneuver against first vehicle which is changing its lane within the minimum stopping distance of the following vehicle. Third, cross and opposing-left turn conflicts are regarded when the vehicle which receives green sign takes evasive maneuver against the vehicle which lost its right-of-way crossing a intersection. As a result of correlation analysis between conflict and accident, it is verified that the suggested conflict criteria in this study ave applicable. And it is proven that estimating safety evaluation for a intersection with conflict data is possible, according to the regression analysis preformed between accident and conflict, EPDO accident and conflict. Adopting the conflict criteria suggested in this study would be both quick and accurate method for diagnosing safety and operational deficiencies and for evaluation improvements at intersections. Further research is required to refine the suggested conflict criteria to extend its application. In addition, it is necessary to develope other types of conflict criteria, not included in this study, in later study.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.2
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• pp.1-6
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• 2015

The RSA is intended to prevent the following five types of events from becoming an accident: landing overruns, landing undershoots, landing veer-offs, takeoff overruns and takeoff veer-offs. The improved models are based on evidence from worldwide accidents and incidents that occurred during the past 27 years. The analysis utilizes historical data from the specific airport and allows the user to take into consideration specific operational conditions to which movements are subject, as well as the actual or planned RSA conditions in terms of dimensions, configuration, type of terrain, and boundaries defined by existing obstacles. This paper shows how to apply the improved models for Risk Assessment of Runway Safety Areas (Airport cooperative research program(ACRP) Report 50) into an airport and the outcome differences between the old models based on ACRP report 3-Analysis of aircraft overrun and undershoots for runway safety areas and the new models from ACRP report 50 in the specific airport.

• Journal of Power System Engineering
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• v.11 no.1
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• pp.5-15
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• 2007

In the recently released accident-investigation report on blade failure, almost 70% of blade failures was found at low pressure turbine blades, and it is well known that main cause is due to the vibration modes. This paper describes the systematic approach on the root cause of the blade failure at L 0 stage, 30MW single flow industrial steam turbine which had tripped by high vibration after ten-month commercial operation. A fracture was found at the only one damping wire hole of 59 blades, and crack was detected at three damping wire holes by NDT. According to the analysis result for the crack fracture surface and the chain of the sequential operational events, we come to the conclusion that a typical high cycle fatigue is the most dominant factor caused to the blade failure, the resonance frequency margin was narrowed by the cut damping wire and the high cycle vibration was amplified, and then the blade was broken at once by the centrifugal force when the crack reached the critical size.

• Journal of Navigation and Port Research
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• v.33 no.9
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• pp.609-614
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• 2009

The traffic of tug/barges which are carrying construction materials, large plants for harbor development, or offshore structures has recently increased in the coast of Korea. The west and south coast of Korea are always congested due to a lot of islands and traffic concentration. Specially tug/barges have higher probability of marine accidents due to their bad maneuverability than others. Considering the operational circumstance and maneuverability, this study was to develop a wide-area monitoring and control system for tug/barges in the coastal area of Korea. The system was made in the form of three program modules i.e. navigation analysis program module, monitoring and control program module, database module. And seven functions were programmed to monitor and control the tug/barges efficiently. These are ship information search, tug/barge information and track management, designated area and safe navigation zone management, fairway management, accident data management, warning of danger, safety information management.

• International Journal of Safety
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• v.9 no.2
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• pp.29-34
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• 2010

When doing maintenance works at the trackside of railway, the method which delivers information on approaching of train to maintenance workers through alarm devices such as the flag or indication light, etc., is being used by locating persons in charge of safety alarm in addition to the maintenance workers at fixed distances in the front and rear of the workplace. Workers maintaining at the trackside may collide with the train since they cannot recognize the approach of train although it approaches to the vicinity of maintenance workplace because of the sensory block phenomenon occurred due to their long hours of continued monotonous maintenance work. The clash or rear-end collision accidents between many maintenance trains called motor-cars can be occurred since there are cases where the signal systems for safe operation of motor-car such as track circuit etc. are blocked or not operated normally. We developed the new safety equipment for protection of trackside maintenance workers using radio frequency signals and bidirectional detection mechanism. The developed safety equipment must analyze the several operational mechanism for each different operation situations. In this paper the analysis results are represented.