• Tunnel and Underground Space
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• v.7 no.3
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• pp.191-201
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• 1997

Geological and geotechnical surveys, in general, should precede the excavation to ensure the safety of the tunnel and should be followed up according to the various geological condition during the excavation. However actually the standard support patterns which were decided during the design step used be insisted for the whole excavation steps in spite of the various geological conditions. OO tunnel was excavated with NATM and a support pattern type-V in weak rocks. When the tunnel was excavated up to 25m long, the severe displacement was generated in the portal area and the shotcrete was damaged to make the cracks and the tunnel face was totally collapsed. It might happen owing to the one-day heavy rain, but the exact reason for that accident should be found out and the new optimal support patternt needed. Consequently three dimensional numerical analysis was applied for the evaluation of the cause of the tunnel collapse instead of two dimensional analysis, because three dimensional analysis can show better the real field phenomenon than two dimensional analysis in which the load distribution methods are adopted for the tunnel excavation. We could simulate the actual situations with three dimensional finite difference code and propose the new optimal support patterns.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.4
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• pp.398-413
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• 2011

For railway safety, it is very important to detect damages of rails at their early stage because any undetected damage in a rail can break the rail and cause a serious railway accident. In this paper, several NDT applicable to rail inspections are described. Major damage types in rails are discussed first and the rail inspection technology using conventional piezoelectric ultrasonic transducers, which is widely adopted for damage detection of rails, is explained. Other NDT being researched or tested for rail inspection are also discussed as complementary technologies to the concurrent contact type ultrasonic inspection. Characteristics of each rail inspection technologies are evaluated in order to provide requirements for future development of a new rail inspection method.

• Journal of Korean Society for Quality Management
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• v.43 no.3
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• pp.327-340
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• 2015

Purpose : Recently, many quality issues are aroused in military forces, such as failures in K-series weapons, combat uniforms' defects and 40mm ammunition explosion accident. To address these problems, Defense Agency for Technology and Quality(DTaQ) introduced new systems such as Manufacturing Readiness Assessment(MRA), Test Report Information System(TRIS) and so on. However, these activities require the human and time resources which cannot be increased in short period. In this paper, we suggest more practical and efficient product examination method. Methods : The most popular and widely used government's quality assurance technique is a sampling method to examine the product. In this research, we first reviewed the DTaQ's quality assurance regulation, then identified several possible problems and finally suggested more efficient and effective sampling plans. Results : We have suggested new sampling framework and evaluated its performance on two military supplies by comparing with other sampling method, and observed that the number of tested samples can be substantially reduced. Therefore, required quality assurance time can be saved. Conclusion : In this paper, we first reviewed the product examination frameworks of DTaQ, PPQMS and DCMA. Then we identified several possible problems which can cause the loss of objectivity and time. To handle these problems, we suggested the new product examination framework and tested the framework to verify the performance.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.782-786
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• 2004

The Wireless-LAN was developed and Wired-LAN substitution from the field which the space where it is restricted is special it used. But, from the field which is various the use is attempted to listen to recently. The shedding of blood which the oceanic accident which occurs recently5 year for is principal is The GMDSS with the formation vessel which is managed with agreement depends here upon and it is a collision of the small-sized vessel which is not managed. Cause the Facilities for the safety-communications system is not introduced is the actual condition in poverty of the small-sized vessel. In this study, recently with the AIS where becomes the introduction it proposed similar function the system which is cheap it does.

• Archives of Craniofacial Surgery
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• v.20 no.5
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• pp.324-328
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• 2019

Intraorbital infection shows a low incidence, but it might cause blindness or even death. This case is unusual in that its origin from a craniofacial bone fracture prior to infection of the maxillary sinus. A 33-year-old female patient was referred for right cheek swelling. When she visited the emergency room, we removed right cheek hematoma and bacterial examination was done. In the past, she had craniofacial bone surgical history due to a traffic accident 6 years ago. Next day, the swelling had remained with proptosis and pus was recognized in the conjunctiva. We planned an emergency operation and removed the pus which was already spread inside the orbit. And the evaluation for sinusitis was consulted to the otorhinolaryngology department simultaneously. There were Prevotella oralis and methicillin-resistant Staphylococcus epidermidis bacterial infection in the intraorbital and sinus respectively. Afterwards, the vigorous dressing was done for over a month with intravenous antibiotics. Though the intraorbital infection was resolved, blindness and extraocular movement limitation were inevitable. In conclusion, close follow up of the maxillary sinus in facial bone fracture patients is important and aggressive treatment is needed when an infection is diagnosed.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.717-723
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• 2011

When the Balise(the device to transmit information between the on-board equipment and the wayside equipment) failure occurs, it may not be able to transmit data(Telegram) required for the train running. And in some cases, it may be able to cause an accident. Therefore, both the Balise failure affecting train safety running and the hazard in accordance with Balise failure require some activities to establish them. General failure mode & hazard analysis associated with the Balise are described in UNISIG SUBSET-036 spec & UNISIG SUBSET-088 spec. And, with reference to these specifications, safety activities are being performed. In recent domestic railway, the train control system applying ETCS(European Train Control System) Level 1, 2 is being serviced and is being planned, and as part of this system, the Balise is being applied. The design-method of the Balise device for each manufacturer are different, therefore the Balise failure mode & failure rate are different, either. But the functionalities & transmission-data format(Telegram) of the Balise in ETCS Level 1, 2 application for each manufacturer are identical. Accordingly, the hazard caused by function-fail can be identical, either. In order to establish these hazard, in this paper, we analyzed the detailed functions of the Balise. And we analyzed the Balise failure types & failure effects in accordance with the detailed functions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1201-1209
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• 2008

In Seoul, there are lots of skyscrapers that have above 60 stories and buildings that have more than 8 basement levels, as well as massive distribution complex region which is connected to subways, departments, malls, hotels, and exhibition halls. When an accident, such as fire and explosion, happens in these areas or structures, if we can't find where fire-fighters are, who go into the building to suppress the fire, we couldn't be sure of their safety as well as effective command. Actually, it may cause much more damage itself and restrict either fire suppression or lifesaving. To protect people's life and properties as much as possible, this study will show the method to construct system of disaster-management supports with effective operation of fire force and scientific fire strategy in the scene by using Ubiquitous technique to enormous disasters.

• Nuclear Engineering and Technology
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• v.37 no.3
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• pp.265-272
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• 2005

Severe accidents in nuclear power plants can cause hydrogen-generating chemical reactions, which create the danger of hydrogen combustion and thus threaten containment integrity. For containment analyses, a three-dimensional mechanistic code, GOTHIC-3D has been applied near source compartments to predict whether or not highly reactive gas mixtures can form during an accident with the hydrogen mitigation system working. To assess the code applicability to hydrogen combustion analysis, this paper presents the numerical calculation results of GOTHIC-3D for various hydrogen combustion experiments, including FLAME, LSVCTF, and SNU-2D. In this study, a technical base for the modeling oflarge- and small-scale facilities was introduced through sensitivity studies on cell size and bum modeling parameters. Use of a turbulent bum option of the eddy dissipation concept enabled scale-free applications. Lowering the bum parameter values for the flame thickness and the bum temperature limit resulted in a larger flame velocity. When applied to hydrogen combustion analysis, this study revealed that the GOTHIC-3D code is generally able to predict the combustion phenomena with its default bum modeling parameters for large-scale facilities. However, the code needs further modifications of its bum modeling parameters to be applied to either small-scale facilities or extremely fast transients.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.72-78
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• 2010

A CFRP (Carbon Fiber-Reinforced Plastic) strengthening method is being very widely used to increase the load-carrying capacity of host structures, especially for bridges. However, not only flexure and shear failures but debonding failure also might occur in CFRP strengthened concrete structures. The CFRP debonding failure would cause a collapse accident of the host structure. Therefore, real-time health monitoring about the CFRP bonding condition is strongly required. In this study, a feasibility of the impedance-based damage detection method using PZT sensors is investigated through a series of experimental study monitoring both concrete cracks and CFRP debonding defects.

• The KIPS Transactions:PartC
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• v.12C no.3 s.99
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• pp.361-368
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• 2005

Internet mail has become a common communication method around the world because of tremendous Internet service usage increment. In other respect, Most Internet users' mail addresses are exposed to spammer, and the damage of Junk mail is growing bigger and bigger. These days, Junk mail delivery problem is becoming more serious, because this is used for an attack or propagation scheme of malicious code. It's a most dangerous dominant cause for computer system accident. This paper shows the Junk mail filtering model and implementation which is based on FQDN (Fully Qualified Domain Name) check and evaluates it for proposing advanced scheme against Junk mail.