• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.261-265
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• 2005

In this paper, we constructed the infrastructure with wireless LAN and Access Point in the indoor environment and implemented the teleoperation. Wireless LAN based teleoperation system is irregular communication delay according to environment condition and occurrence possibility of blackout is very high. In this paper, In case these problem happened, we measured communication delay time by real time, and did mobile robot to control harmoniously through vision and force reflection information. Also, we present obstacle-avoidance mode that mobile robot can travel without collision using direction information in case communication delay time is large. We proved usefulness of presented algorithm through teleoperation experiment to apply presented algorithm.

• Electronics and Telecommunications Trends
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• v.13 no.5 s.53
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• pp.65-78
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• 1998

B-ISDN은 다양한 속도의 영상, 음성, 데이터 등에 의한 멀티미디어 통신서비스를 실현하기 위해, Asynchronous Transfer Mode (ATM)를 전송방식으로 채용하고 있으며, ITU--T 등 국제표준화 기구에서 표준화가 진행되고 있다. 본 고에서는 B-ISDN의 서비스품질에 대해 ATM 셀 전송품질(ATM Layer Cell Transfer Performance), 접속품질(Call Processing Performance), 안정품질(Availability Performance)로 나누어 고찰하고, 이들을 반영한 ITU--T의 서비스품질 표준화 동향에 대해 ATM Forum의 동향과 연관지어 기술하였다. 특히, ATM 셀 전송품질을 사용자가 지정한 Quality of Service (QoS) 클래스 방식과 QoS 파라미터 방식의 제공에 대해 고찰하였으며, B-ISDN을 기반으로 한 Internet Protocol (IP) 망과 세계정보통신기반 Global information Infrastructure (GII)의 품질표준화 동향에 대해서도 소개하였다.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.985-990
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• 2005

The success of road transportation, in dominating the surface movement of freight, is now threatened by increased traffic congestion, falling average motorway speed and rising in logistics costs, oil price. Due to the necessity for an effective transport system, we need to improve domestic transport infrastructure to reduce logistics cost by shifting to rail system. To analysis the demand characteristics in advance against these hypothetical circumstances, Stated Preference, which is called SP, approaches have been adopted to analysis the shipper's mode choice behaviors as RP(Revealed Preference) approaches are not appropriate. The results also indicate that the most effective policy to divert the freight volume from road to railway is to reduce freight rates for the railway with improved reliability.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1007-1012
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• 2003

With deterioration of the nation's infrastructure comes the growing, need for effective means of rehabilitating structures. Possibly one for the most challenging tasks is to upgrade the overall capacity of concrete structure. This study focused on the flexural behavior of reinforced concrete slabs strengthened by PS strand and polymer mortar in the tension zone. The properties of slabs are 70×12㎝ rectangular and over a 220㎝ span. Test parameters in this experimental study were placing thickness, chipping, the number of strand, the kind of mortar. Attention is concentrated upon overall bending capacity, deflection, ductility index, failure mode and crack development of repaired and rehabilitated slabs.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.642-646
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• 2008

Signaling system, for which ensuring safe train operation, must be a fail-safe system with higher reliability and safety. TCS has made significant improvements both on signaling system, from relay based ground signaling system to computer based on-board system, and on driving mode, form low speed and low density driving to TCS supporting high speed and high density driving. In addition, TCS has been applied to rolling stock with a wide variety of context according to the characteristics of rolling stock or railway infrastructure. In this paper, therefore, we confirmed the basic concept of ATC system and analyzed its development process in technology context via referencing international cases and ATC systems introduced and applied in Korea. Based on those analyses, we suggested the new TCS development strategy for its suitable application to high speed line, conventional line and metro, and we also provided technical considerations related to TCS application.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.10
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• pp.2687-2702
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• 1996

It is desirable that the implementation of next generation information infrastructure is the Integrated Network combining the satellite and the terrestrial network. The application of the ATM network being the dominant infrastrure of terrestrial network to the satellite network is being studied variously. Considering these concepts, this paper analyzes due to ATM transport via satellite, evaluates the degradation of QoS and proposes reliable method of ATM cell transport via satellite. Because ATM is investigated with the optical fiber which is almost error free characteristics, the practical application of ATM transport via satellite essentially need the channel coding(FEC:Forward Error Correction) to enhance BER performance. But using the FEC coding, satellite link has burst error characteristics which evoke severe performance degradation fo ATM QoS. Therefore in satellite link, we analyze burst error characteristics using experimental results of computer simulation. Then to compensate these characteristics, based on this analysis and HEC dual mode algorithm we propose various interleaver structures(Block interleaver, Intra interlever, and Inter-Intra interleaver) to improve cell transmission QoS. We execute performance evaluations of iterleaver structures by computer simulation.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.961-963
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• 1998

Power telecommunication networks, being used to support the operation and management of power utility services, exhibits different characteristics from those of public domain networks. KEPCO is planning to evolve its own power network infrastructure to exploit ATM (Asynchronous Transfer Mode) technology. The ATM network to be developed needs to effectively utilize existing network of KEPCO and to fully support new and emerging power-utility-services. This paper summarizes the features of power communication services and the characteristics of Power telecommunication networks, and reports our evolution methodology for KEPCO network.

• International Journal of Reliability and Applications
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• v.8 no.2
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• pp.183-197
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• 2007

There is a growing trend for asset intensive industries to outsource maintenance services of their complex assets since outsourcing through service contract reduces upfront investments in infrastructure, expertise and specialised maintenance facilities. Estimation of costs for such contracts is complex and it is important to the user and the service providers for economic variability. The service provider's profit is influenced by many factors such as the terms of the contract, reliability of asset, and the servicing strategies, costs of resources needed to carryout maintenance. There is a need to develop mathematical models for understanding future costs to build it into the contract price. Three policies for service contracts are proposed in this paper considering the concepts of outsourcing maintenance service of assets to the service providers. Conceptual models are developed for estimating servicing costs of outsourcing through service contracts by considering time dependent failure mode.

• Wind and Structures
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• v.16 no.4
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• pp.393-409
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• 2013

This paper uses ten years of on-site monitoring data for the Confederation Bridge to derive wind loads and investigate whether the bridge has experienced its design wind force effects since its completion in 1997. The load effects derived using loads from the on-site monitoring data are compared to the load effects derived using loads from the 1994 and 2009 wind tunnel aerodynamic model tests. The research shows, for the first time, that the aerodynamic model-based methodology originally developed in 1994 is a very accurate method for deriving wind loads for structural design. The research also confirms that the bridge has not experienced its specified (i.e., unfactored) wind force effects since it was opened to traffic in 1997, even during the most severe event that has occurred during this period.

• Structural Monitoring and Maintenance
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• v.5 no.4
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• pp.429-443
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• 2018

Fatigue is a principal failure mode for steel structures, and it is still less understood than any other modes of failure. Fatigue life estimation of metal bridges is a major issue for making cost effective decisions on the rehabilitation or replacement of existing infrastructure. The fatigue design procedures given by the standard codes are either empirical or based on nominal stress approach. Since the fatigue life estimation through field measurements is difficult and costly, more researches are needed to develop promising techniques in the fatigue analysis of bridges through Finite Element Analysis (FEA). This paper aims to develop a methodology for the Fatigue life estimation of railway steel bridge using FEA. The guidelines of IIW-1823-07 were used in the development of the methodology. The Finite Element (FE) package ANSYS and the programming software MATLAB were used to implement this methodology on an Indian Railway Standard (IRS) welded plate girder bridge. The results obtained were compared with results from published literature and found satisfactory.