• Proceedings of the KSR Conference
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• 2008.11b
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• pp.281-285
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• 2008

Corrosion of metallic structures arises when an electric current flows from the metal into the electrolyte such as soil and water. The potential difference across the metal-electrolyte interface, the driving force for the corrosion current, can emerge due to a variety of temperature, pH, humidity and resistivity etc.. With respect to a given structure, a stray current is to be defined as a current flowing on a structure that is not part of the intended electrical circuit. Stray currents are caused by other cathodic protection installations, grounding systems and welding posts, referred to as steady state stray currents. But most often traction systems like railroads and tramlines are responsible for large dynamic stray currents. This type of stray current is generally results from the leakage of return currents from large DC traction systems that are grounded or have a bad earth-insulated return path. This paper investigates the reports, which is made for protecting the electrical corrosion by the DC traction stray current before the construction period.

• Journal of the Speleological Society of Korea
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• no.52
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• pp.17-24
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• 1997

The Environment consolation and the Tour Resources Development of the Cave. The conservation and the development of the cave are complementary to each other. On account of Keepiny on changing, the cave is similar to living thing. Therefore, the cave development mocks the environment changed by the microbes and the mosses by many factors. But if can make the people around the cave get richer and richer by the visitors. If we need to develop some caves, first of all the safety diagnoses must be executed, about the geographic structures, path facilities, electronic ones, and so on.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.107-110
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• 2008

In this study, we propose a system for setting a Destination on CNS(Car Navigation System) or PNS(Personal Navigation System). The present Navigation does set the destination by only static method like name search, address search and wire telegraph telephone number search. But, the kind of setting a static destination does not reflect the dynamic moving situation. So we suggest setting the destination of navigation using Identifier of moving terminal. And it includes privacy protection on personal position information

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.6
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• pp.616-622
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• 2000

This paper concerns the application of smoke and fire spread to road tunnel fire problems. When a road tunnel is on fire. a fire protection system of road tunnel have to offer an adequate escape space to human. Therefore, this study carried out a simulation for predicting a spreading path of smoke and fire. The evolution of the flow field is simulated with the low Reynolds number k-$\varepsilon$ turbulent model and SIMPLE algorithm based on the finite volume method.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.2
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• pp.218-226
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• 2024

According to the actual situation of a university, the emergency evacuation simulation is modeled based on the physical sign, evacuation speed and personnel ratio using the pathfinder software.The experimental construction export utilization rate is compared with the preliminary simulation scenario. The simulation results show that the utilization rate of evacuation stairs and evacuation exits is significantly improved.The optimized solution can provide the most effective evacuation passage, and the research results can provide the basis for the rational planning and management of evacuation passage in university experiment building.

• Journal of the Korean Institute of Gas
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• v.13 no.2
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• pp.1-6
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• 2009

With respect to a given structure, a stray current is to be defined as a current flowing on a structure that is not part of the intended electrical circuit. Most often DC-powered traction systems like railroads and tramlines are responsible for large dynamic stray currents. This type of stray current is generally results from the leakage of return currents from large DC traction systems that are grounded or have a bad earth-insulated return path. At the place where the current leaves the rail and metallic structures, electrolytic corrosion may take place. This paper investigates the domestic conditions on the electrolytic corrosion protection of buried metallic structures adjacent to DC traction systems by survey.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.1
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• pp.40-47
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• 2013

By virtue of Rec. ITU-R P.1546 and geography information system, interference analysis for the fixed wireless system and radar has been presented based upon the frequency-distance rules with minimum coupling loss, and a comprehensive methodology for assessing interoperability between systems was examined in terms of received signal, protection ratio, frequency dependent rejection. Also to find the antenna gain from a discrimination angle, a useful S-I plane was introduced based on signal and interference vectors derived from the real map with geographic information. To show some computational results, geography information on the map was taken for the given area, and field strength and path profile were illustrated for the radar and fixed wireless system operating at 2.7 GHz, for convenience. In addition the interference effect of receiver was also checked as a function of radar beam direction including protection ratio and frequency dependent rejection. The developed interference analysis can be actually applied to evaluate interoperability for wireless systems in the VHF and UHF bands.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.6
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• pp.1463-1479
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• 2013

In this paper, we propose an unequal protection physical coding sub-layer (PCS) forward error correction (FEC) scheme for efficient and high-quality transmission of video data over optical access networks. Through identifying and resolving the unequal importance of different video frames and passing this importance information from MAC-layer to PCS, FEC scheme of PCS can be adaptive to application-layer data. Meanwhile, we jointly consider the different channel situations of optical network unit (ONU) and improve the efficiency of FEC redundancy by channel adaptation. We develop a theoretical algorithm and a hardware method to achieve efficient FEC assignment for the proposed unequal protection scheme. The theoretical FEC assignment algorithm is to obtain the optimal FEC redundancy allocation vector that results in the optimum performance index, namely frame error rate, based on the identified differential importance and channel situations. The hardware method aims at providing a realistic technical path with negligible hardware cost increment compared with the traditional FEC scheme. From the simulation results, the proposed Channel and Application-layer data Adaptation Unequal Protection (CAAUP) FEC scheme along with the FEC ratio assignment algorithm and the hardware method illustrates the ability of efficient and high-quality transmission of video data against the random errors in the channel of optical access networks.

• Journal of IKEEE
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• v.20 no.4
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• pp.361-366
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• 2016

This paper presents the ESD protection circuit with improved electrical characteristic and area efficiency. The proposed ESD protection circuit has higher holding voltage and lower trigger voltage characteristics than the 3-Stacking LVTSCR. In addition, it has only two stages and has improved Ron characteristics due to short discharge path of ESD current. We analyzed the electrical characteristics of the proposed ESD protection circuit by TCAD simulator. The proposed ESD protection circuit has a small area of about 35% compared with 3-Stacking LVTSCR, The proposed circuit is designed to have improved latch-up immunity by setting the effective base length of two NPN parasitic bipolar transistors as a variable.

• Journal of KIISE:Information Networking
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• v.31 no.2
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• pp.233-241
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• 2004

In this paper, we propose a packet-lossless fast rerouting scheme at a link/node fault in MPLS (Multiprotocol Label Switching) network with minimized accumulated buffer delay problem at ingress node. The proposed scheme uses a predefined, alternative LSP (Label Switched Path) In order to restore user traffic. We propose two restoration approaches. In the first approach, an alternative LSP is initially allocated with more bandwidth than the protected working LSP during the failure recovery phase. After the failure recovery, the excessively allocated bandwidth of the alternative LSP is readjusted to the bandwidth of the working LSP. In the second approach, we reduce the length of protected working LSP by using segment-based restoration. The proposed approaches have merits of (ⅰ) no buffer delay problem after failure recovery at ingress node, and (ⅱ) the smaller required buffer size at the ingress node than the previous approach.