• Tribology and Lubricants
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• v.22 no.4
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• pp.225-229
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• 2006

The issue with the drainpipe now a day is that they are laid underground. Causing us to perform additional work to repair, such as digging up the ground and peeling off the insulator that surrounds the pipe. And such series works are difficult that concession appears from government and municipal office. However, if we can save time and money. Performance of piping robot that we are studied in existing session through fixing unit and improvement of cutting bit shorten and wished to heighten work efficiency. And we are trying to develop a unit that can cut up the projecting parts which connects with the interior part of the drainpipes.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.143-148
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• 2003

The issue with the drainpipe now a day is that they are laid underground. Causing us to perform additional work to repair, such as digging up the ground and peeling off the insulator that surrounds the pipe. And such series works are difficult that concession appears from government and municipal office. However, if we can save time and money. Performance of piping robot that we are studied in existing session through fixing unit and improvement of cutting byte shorten and wished to heighten work efficiency. This is why we are trying to develop a unit that can cut up the projecting parts which connects with the interior part of the drainpipes.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2051-2053
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• 1999

In this work, PD patterns and electrical trees are observed by use of the XLPE cable insulation. and the tree initiation voltage related to the contamination are also measured in order to calculate the electric stress necessary for the design of cable insulation. Throughout these works, correlation between the PD pattern and the shape of electrical tree has been observed that there may exist three distinct pattern of PD dependence on the stage of tree propagation, Such correlation could bring a basic information in connection with the partial discharge of cable system. It was also found that the electrical stress necessary for the initiation of electrical tree was measured to the 290kV/mm for the 154kV XLPE cables manufactured in KOREA.

• 한국IT서비스학회:학술대회논문집
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• 2010.05a
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• pp.211-215
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• 2010

본 연구 성과는 국내토목구조물의 유지관리 업무를 지원하는 분야에 해당한다. 현재 우리나라 토목시설물은 법정비를 통해, 유지관리업무를 체계화시켜나가고 있는 상태이지만, 아직 그 결과물에 대한 DB 시스템이 일반화 되어 있지 못하며, 일부 개발된 툴들도 서로간의 유기적인 연결은 부족하다. 본 연구를 통해 개발한 지하구조물 유지관리 DB시스템을 이용해서 시설물 관리주체, 진단업체, 유지관리업체들이 상호간에 유기적으로 연결되고 효율적으로 데이터들을 관리할 수 있는 시스템을 제안하여, 국내 기간산업의 유지관리 업무 효율성을 높이는데 이바지 하고자 한다.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.534-536
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• 2003

It is important to classily fault types and discriminate fault section by any detecting technique for combined transmission lines. This paper proposes the technique to classify the fault types and fault section using neuro-fuzzy systems. Neuro-fuzzy systems are composed of two parts to perform different works. First, neuro-fuzzy system for fault type classification is performed with approximation coefficient of currents obtained by wavelet transform. Another neuro-fuzzy system discriminates the fault section between overhead and underground with detail coefficients of voltage and current. In this paper, neuro-fuzzy system shows the excellent results for classification of fault types and discrimination of fault section.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.181-188
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• 2002

Water flow rate into the tunnel usually determined by numerical analyses and mathematical formulas using water levels and permeability is obtained only a few limited districts of the whole tunneling site. However, underground is not a homogeneous but complicated mass. Therefore these methods can't reflect structural and geological aspects. In this study, assuming that the mountain stream in droughty season is to be the same as baseflow of its basin, hydrological method is applied to predict the constant water flow rate into the tunnel on construction field. Prediction of constant water inflow rate is performed on each section of tunnel construction field divided into 20 sections.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.253-256
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• 2004

Recently, construction works of scale are getting larger with economic growth. Shotcreting is one of major processes in tunnels construction. Accelerator is used in tunnel and underground structures to ensure early strength of shotcrete. Silicate based accelerator and aluminate based accelerator is getting widely in the field. But these accelerators have many problems due to decesase of long-term strength and low quality of the hardened shotcrete. in order to solve these problems, recently developed powder types cement mineral accelerator. In this study, we tested chloride permeability, freezing and thawing and accelerated carbonation of shotcrete. As a result of the test, wet-mixed shotcrete with powder types cement mineral accelerator exhibited durability improvement compared to the conventional shotcrete accelerator.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.412-415
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• 2003

It is important to classily fault types, discriminate fault section and calculate the fault location by any detecting technique for combined transmission lines. This paper proposes the technique to classily the fault types and fault section using neuro-fuzzy systems. Neuro-fuzzy systems are composed of three parts to perform different works. First, neuro-fuzzy system for fault type classification is performed with approximation coefficient of currents obtained by wavelet transform. The second neuro-fuzzy system discriminates the fault section between overhead and underground with detail coefficients of voltage and current. The last neuro-fuzzy system calculates the fault location with impedance in this paper, neuro-furry system shows the excellent results for classification of fault types and discrimination of fault section.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.11a
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• pp.122-123
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• 2019

Recently, road cutting works are frequently performed to repair aging underground utilities. However, the conventional road pavement cutting equipment in Korea generates a lot of noise and dust, and the development of high performance and eco-friendly equipment is required. This study classifies road cutting work and analyzes its work characteristics before improving road cutting machine. The classification and analysis results of this study will be used for the future productivity analysis and evaluation of road cutter developed.

• International conference on construction engineering and project management
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• 2005.10a
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• pp.824-829
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• 2005

This paper focuses on construction cost volatility for the purpose of private sector investment by use of a financial model with key indices of IRR and DSCR (Debt Service Coverage Ratio). A case project, 1,000 MW pumped storage hydropower plant, has shown that its financial impacts by cost volatility of underground works are less measured than interest rates impacts by interest rate of loans. Probabilistic analysis of costs under geotechnical conditions has been made by Indicator Kriging method. And, in the modeling of interest rates, geometric Brownian motion has been applied. Both of these impacts are measured on the same financial model.