• International Journal of Highway Engineering
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• v.13 no.1
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• pp.119-127
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• 2011

The main purpose of this paper is to apply Zone 30 system which is being experimented in advanced country for the solution of controlling the residential street's speed to our country with the consideration of the real condition of our street and traffic and to run this system as an example to analyze the effect and at the same time, analyze the problem and get appropriate preparation for this system to be widespread. The area to run this model project is Goyang City Ilsan-Gu.($0.65km^2$) which is close with the commercial area reflecting the opinion of experts and an on-site verification by the National Police Agency T/F and is having a heavy pedestrian traffic and the risk of pedestrian accident. Firstly we defined residential street and residential street area to review the system and devided the residential street type to establish a plan of operation. Afterwards, we thoroughly examined the model project area and analyzed the problem and solution. We finally completed establishing a facilities by conference with a local autonomous entity with the improvement of facility's sketch at the analysis of the model project area. The result of effects analysis which we devided after and before of establishment is that vehicle speed be reduced 5~15km/h, and traffic accidents has decreased by 24 percent.

• Informatization Policy
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• v.19 no.4
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• pp.63-82
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• 2012

The world's best level of ICT(Information, Communication and Technology) infrastructure has experienced the world's worst level of ICT accident in Korea. The number of major accidents of privacy invasion has been three times larger than the total number of Internet user of Korea. The cause of the severe accident was due to big data environment. As a result, big data environment has become an important policy agenda. This paper has conducted analyzing the accident case of data spill to study policy issues for ICT security from a social science perspective focusing on risk. The results from case analysis are as follows. First, ICT risk can be categorized 'severe, strong, intensive and individual'from the level of both probability and impact. Second, strategy of risk management can be designated 'avoid, transfer, mitigate, accept' by understanding their own culture type of relative group such as 'hierarchy, egalitarianism, fatalism and individualism'. Third, personal data has contained characteristics of big data such like 'volume, velocity, variety' for each risk situation. Therefore, government needs to establish a standing organization responsible for ICT risk policy and management in a new big data era. And the policy for ICT risk management needs to balance in considering 'technology, norms, laws, and market'in big data era.

• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.605-612
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• 2013

Removal of decay heat from an operating reactor during a prolonged station blackout condition is a big concern for reactor designers, especially after the recent Fukushima accident. In the case of a prolonged station blackout condition, heat removal is possible only by passive means since no pumps or active systems are available. Keeping this in mind, the AHWR has been designed with many passive safety features. One of them is a passive means of removing decay heat with the help of Isolation Condensers (ICs) which are submerged in a big water pool called the Gravity Driven Water Pool (GDWP). The ICs have many tubes in which the steam, generated by the reactor core due to the decay heat, flows and condenses by rejecting the heat into the water pool. After condensation, the condensate falls back into the steam drum of the reactor. The GDWP tank holds a large amount of water, about 8000 $m^3$, which is located at a higher elevation than the steam drum of the reactor in order to promote natural circulation. Due to the recent Fukushima type accidents, it has been a concern to understand and evaluate the capability of the ICs to remove decay heat for a prolonged period without escalating fuel sheath temperature. In view of this, an analysis has been performed for decay heat removal characteristics over several days of an AHWR by ICs. The computer code RELAP5/MOD3.2 was used for this purpose. Results indicate that the ICs can remove the decay heat for more than 10 days without causing any bulk boiling in the GDWP. After that, decay heat can be removed for more than 40 days by boiling off the pool inventory. The pressure inside the containment does not exceed the design pressure even after 10 days by condensation of steam generated from the GDWP on the walls of containment and on the Passive Containment Cooling System (PCCS) tubes. If venting is carried out after this period, the decay heat can be removed for more than 50 days without exceeding the design limits.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.208-215
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• 2017

When persistent oil, such as crude oil or Bunker C oil, is spilled at sea, viscosity increases through the weathering process. Equipment that can collect this oil when mixed with floating marine debris is very limited. In this study, devices that can be attached to the outside of existing oil skimmers have been applied to the inside of the main body, to develop an unmanned conveyor belt type floating marine debris and high viscosity oil recovery skimmer, which is composed of a conveyor belt, a sweeper with a forced inflow device, and a collection tank equipped with a buoyant body. The resulting skimmer was operated at a speed of 1.2 knots at a distance of 30 m in a sea area test. It was stable when moving laterally in any direction. An oil recovery performance test was conducted using a portable storage tank, and oil was recovered from a minimum of $7.8k{\ell}/h$ to a maximum of $23.3k{\ell}/h$. Moreover, recovery of $7.7k{\ell}/h$ was obtained in a wave water tank test with floating marine debris such as PET bottles and oil mixed. If the equipment developed in this study was used in the field for oil pollution accidents, it could be expected to contribute to improved response capability. We believe our equipment could be used in further studies to improvement the performance of existing portable oil skimmers.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.377-386
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• 2021

The A60 class deck penetration piece is a fire-resistant system installed on a horizontal compartment to prevent flame spreading and protect lives in fire accidents in ships and offshore plants. This study deals with approximate optimization using discrete variables for the fire resistance design of an A60 class deck penetration piece using different surrogate models and a genetic algorithm. Transient heat transfer analysis was performed to evaluate the fire resistance design of the A60 class deck penetration piece. For the approximate optimization of the piece, the length, diameter, material type, and insulation density were applied to discrete design variables, and temperature, productivity, and cost constraints were considered. The approximate optimum design problem based on the surrogate models was formulated such that the discrete design variables were determined by minimizing the weight of the piece subjected to the constraints. The surrogate models used in the approximate optimization were the response surface model, Kriging model, and radial basis function-based neural network. The approximate optimization results were compared with the actual analysis results in terms of approximate accuracy. The radial basis function-based neural network showed the most accurate optimum design results for the fire resistance design of the A60 class deck penetration piece.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.58-58
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• 2016

This study aims to enhance Korea's competitiveness by taking the lead in the international standardization and relevant global market. This is to be achieved by performing the role of First Mover through the resolute investment from Fast Follower that is servile to the decision of the organization in the e-Navigation strategy that has been promoted by the IMO. The study methodology is an integrated approach. It is established by modelling LSCM G2B2C2 Platform in maritime safety/security logistics and applied to the enhancement of maritime safety/security in global LSCM. This paper externally contributes to the reduction of world maritime accidents and exalt the national prestige; internally, the enhancement of the national competitiveness through the improvement of shipping port logistics and others. These eventually contribute to Korea's economic development that is combined by both theory and practice and of practical use of the integrated approach.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.5D
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• pp.727-737
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• 2011

The emergency restoration scenarios for efficient railway accident management and restoration were developed. The emergency restoration procedures defined by the worst case of emergency restoration and the important events was proposed based on questionnaires from specialists and the result of survey. Via these studies, the railway accident in the tunnel could be the worst case among all railway accident types. Therefore, educations for a restoration team in confined area condition should be planned and performed to recover the worst case accident. In order for the emergency restoration, when a railway accident is occurred, the restoration should be performed in orders of handing collapse of facilities, burying track, and derailment of vehicle in tunnel based on the statistical analysis. The result of priorities were established by the period of restoration. The standard operation system for efficient railway accident management was developed by synthesizing the worst case for rapid emergency restoration, and important events for the standard operation procedures according to each emergency restoration type. Through this study, the restoration operation system of railway accident are recommended. This paper suggests to develop emergency restoration scenarios for the efficient railway accident management and recovery system. The study results will contribute not only for insuring punctuality, but also for minimizing delays from accidents. Therefore, emergency restoration scenarios will play a major role in the SOP for the damage limitation and the prevention of accident spread.

• Fire Science and Engineering
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• v.30 no.2
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• pp.68-74
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• 2016

In semi-transverse ventilation system applied for road tunnel, adjustment of the port opening ratio is an essential part for uniform airflow rate per unit length over the entire tunnel. However, it has not been considered decently throughout the design process and operating of the tunnel. Therefore, in this study, we developed a program for the calculation of the opening size ratio of supply or exhaust port in transverse ventilation system and carried out the research to present a management plan for the port. In supply duct system, the opening size of the port had a tendency to increase and then decrease later when it gradually becomes closer toward the bulkhead at the beginning of the duct the minimum opening degree is to appeared as 56%. In the exhaust system, port size is the smallest at the beginning of duct as 15%, has shown a tendency to increase towards the bulk head. As results of estimating the air flow rate for 300 m intervals, the exhaust flow rate in the center of tunnel appeared to be extremely low as 8.1% and 12.5% when port size is constant and is adjusted supply type. Thus, even if the normal ventilation efficiency is declines, yet it is highly recommend adjusting the port size in order to obtain a uniform flow rate at fire accidents.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.32-38
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• 2020

This study examined the problems of existing vehicles to propose alternatives to improve the crashworthiness of railway freight cars through collision acceleration analysis using a one-dimensional collision analysis method. A collision scenario of railway shunting and crash accidents was selected from the collision accident cases and international standards. A one-dimensional collision simulation using LS-DYNA was performed according to those scenarios. As a result, the acceleration level of the freight wagon was calculated to be under 2g and was predicted to meet the EN 12663 standard in the shunting situation. On the other hand, the result of crash simulation with an impact velocity between 10 and 15 km/h revealed the shock absorber capacity of the railway coupler to be insufficient in a crash situation, resulting in increased acceleration, and carbody deformation could be predicted. As a method of improving the crashworthiness, a deformation tube-type energy absorber was applied to the coupler system, and collision analysis was performed again with new energy absorption strategy. Overall, the simulation showed that the acceleration level was decreased by 12% of the conventional freight-car energy absorption system.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.7
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• pp.217-224
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• 2022

Today, with the development of technology and industry, fire accidents in special buildings are increasing as special buildings increase. However, despite the rapid development of information and communication technology, human casualties are steadily occurring due to the underdeveloped and ineffective indoor fire alarm system. In this study, we confirmed that the existing indoor fire alarm system using acoustic alarm could not deliver a sufficiently large alarm to the in-room personnel. To improve this, we designed and implemented a fire alarm system using edge computing and beacons. The proposed improved fire alarm system consists of terminal sensor nodes, edge nodes, a user application, and a server. The terminal sensor nodes collect indoor environment data and send it to the edge node, and the edge node monitors whether a fire occurs through the transmitted sensor value. In addition, the edge node continuously generate beacon signals to collect information of smart devices with user applications installed within the signal range, store them in a server database, and send application push-type fire alarms to all in-room personnel based on the collected user information. As a result of conducting a signal valid range measurement experiment in a university building with dense lecture rooms, it was confirmed that device information was normally collected within the beacon signal range of the edge node and a fire alarm was quickly sent to specific users. Through this, it was confirmed that the "blind spot problem of the alarm" was solved by flexibly collecting information of visitors that changes time to time and sending the alarm to a smart device very adjacent to the people. In addition, through the analysis of the experimental results, a plan to effectively apply the proposed fire alarm system according to the characteristics of the indoor space was proposed.