• Journal of the Korean Society for Precision Engineering
• /
• v.16 no.5 s.98
• /
• pp.175-185
• /
• 1999

Acoustic emission(AE) measurement was carried out to evaluate the fracture behavior of high tension steel. Fracture toughness $K_{AE}$ could be determined reasonably by using the load value corresponding to an abrupt change of the accumulated AE counts AE emitted from the test specimens. AE characteristics of the base metal, the weld metal and the heat-affected zone could be distinguished using a constant value b which represented the AE amplitude distribution, Consequently the structure integrity can be evaluated by variation of the constant b at the load level. In addition it was found that AE signals due to crack growth have high amplitude but low rise time and duration.

• Journal of the Korean Society for Railway
• /
• v.6 no.3
• /
• pp.156-162
• /
• 2003

Due to almost all tracks of new Kyoungbu high-speed lines(HSL) consisting of bridges and tunnels, HSR operational safety management is very important factor for passenger safety and preventing catastrophic event. Especially, it is important to approach the scene of the accident and assist in saving lives as soon as possible under emergency conditions. Therefore it is essential to prepare access methods and available resources in advance in order to support emergency correspodances promptly and effectively. This paper persents an application of geographical information system(GIS) for developing emergency management system as well as batabase system on tracks and facilities, electric/communication equipment and safety equipment required to support emergencies. The on-site information on the proximity of HSL is expressed on the numerical map, which can be helpful to call external supports such as medical service, local authorities, police offices, fire brigades, and etc. for the emergency situations.

• Safety and Health at Work
• /
• v.8 no.1
• /
• pp.42-48
• /
• 2017

Background: As one of the most frequently occurring accidents in a chemical plant, a fire accident may occur at any place where transfer or handling of combustible materials is routinely performed. Methods: In particular, a jet fire incident in a chemical plant operated under high pressure may bring severe damage. To review this event numerically, Computational Fluid Dynamics methodology was used to simulate a jet fire at a pipe of a compressor under high pressure. Results: For jet fire simulation, the Kemeleon FireEx Code was used, and results of this simulation showed that a structure and installations located within the shelter of a compressor received serious damage. Conclusion: The results confirmed that a jet fire may create a domino effect that could cause an accident aside from the secondary chemical accident.

• Proceedings of the KIPE Conference
• /
• 2018.11a
• /
• pp.9-11
• /
• 2018

This paper studies on the development of an electric fire prevention system with the detection and alarm in case of parallel arc fault occurrence in low voltage distribution lines. The proposed detector has the characteristics of high speed operation responsibility and superior system reliability from composition using a large number of semiconductor devices. The line voltage is always feedback, and when an arc or a spark occurs, these are detected by the microcomputer. In addition, we design and develop algorithms using high speed and high precision microcomputer. A new conceptual control technique is adopted that RCD cuts-off by forming a forced short circuit between the phase voltage and ground in the event of an electrical accident. Some experimental tests of the proposed system also confirm practicality and the validity of the analytical results.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.18 no.7
• /
• pp.980-988
• /
• 1993

In this paper, performance of 8-ISDN traffic for the buffer size which is requested of important parameters in switch/multiplexer of B-ISDN with multimedia traffic is analyzed. Multimedia traffic is modeled as a traffic, which is composed of poisson distribution traffic and burst traffic with exponential/geometric ON time duration(Burst duration) Performance of traffic which is modeled as a multimedia traffic is analysed and buffer size, can provide the high quality service, is presented for the cell loss probability. It is simulated using event scheduling approach method which is provided by simulation package, PC SIMSCRIPT II.5. Simulation program is composed of PREAMBLE, MAIN, INITIAL, ARRIVAL, DEPARTURE and STOP·SIM modules. Specially, in case of mixed traffic simulation, ARRIVAL module is composed of ARRIVAL I and ARRIVAL II, and cells are generated independently by each module.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2005.04a
• /
• pp.172-175
• /
• 2005

The numerical simulation is performed for the acoustic emission and the wave propagation due to fiber breakage in single fiber composite plates by the finite element transient analysis. The acoustic emission and the following wave motions from a fiber breakage under a static loading is simulated to investigate the applicability of the explicit finite element method and the equivalent volume force model as a simulation tool of wave propagation and a modeling technique of an acoustic emission. For such a simple case of the damage event under static loading, various parameters affecting the wave motion are investigated for reliable simulations of the impact damage event. The high velocity and the small wave length of the acoustic emission require a refined analysis with dense distribution of the finite element and a small time step. In order to fulfill the requirement for capturing the exact wave propagation and to cover the 3-D simulation, we utilize the parallel FE transient analysis code and the parallel computing technology.

• Journal of the Korean Institute of Gas
• /
• v.14 no.5
• /
• pp.38-44
• /
• 2010

This treatise analyzed the risk of propylene transported by railroad through quantitative analysis. As a result of survey on propylene transportation route, Iksan station, Suncheon station and Jeonju station were selected as object regions those were expected to have high accident risks. This treatise deduced the scenario of accident and the occurrence rate in accordance with the type of accident possibly to be happening during propylene transportation through ETA( Event Tree Analysis), and expressed the level of personal, social risks after calculating the level of demage influencing over surroundings based on the evaluation for the expected accident damage through PHAST 6.53.

• Journal of Electrical Engineering and Technology
• /
• v.4 no.4
• /
• pp.476-484
• /
• 2009

This paper deals with improvements to the special protection schemes (SPS) which have been applied to the low probability and high impact contingencies in the Korea Electric Power Corporation (KEPCO) system since 2004. Among them, the SPS for voltage instability in the Seoul metropolitan area is considered in this paper, and is a form of event-based undervoltage load shedding with a single-step scheme. Simulation results based upon a recent event that occurred on 765kV lines show that the current setting values of the SPS have to be revised and enhanced. In addition, by applying response-based multi-step undervoltage load shedding (UVLS) schemes to severe contingencies in the system, more effective results than those of the existing single-step SPS can be obtained. Centralized and distributed UVLS schemes are considered in the simulation. ULTC-based load recovery models and over excitation limiters (OXL) for the KEPCO system are also included in the long-term voltage instability studies.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.11
• /
• pp.1778-1783
• /
• 2006

Event-specific PCR detection methods are the primary trend in genetically modified (GM) plant detection owing to their high specificity based on the flanking sequence of the exogenous integrant. Therefore, this study describes a real-time PCR system for event-specific GM canola GT73, consisting of a set of primers, TaqMan probe, and single target standard plasmid. For the specific detection of GT73 canola, the 3'-integration junction sequence between the host plant DNA and the integrated specific border was targeted. To validate the proposed method, test samples of 0, 1, 3, 5, and 10% GT73 canola were quantified. The method was also assayed with 15 different plants, and no amplification signal was observed in a real-time PCR assay with any of the species tested, other than GT73 canola.

• Convergence Security Journal
• /
• v.12 no.4
• /
• pp.77-84
• /
• 2012

The control network has been operated in a closed. But it changes to open to external for business convenience and cooperation with several organizations. As the way of connecting with user extends, the risk of control network gets high. Thus, in this paper, proposed the technique of an anomalous event detection using white-list for control network security and minimizing the cyber threats. The proposed method can be collected and cataloged of only normal data from traffic of internal network, control network and field devices. Through way to check the this situation, we can separate normal and abnormal behavior.