• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.312-313
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• 2018

As global climate change leaded to extensive natural disaster and radical deterioration of infrastructures, there was increased attentions for the evaluation of infrastructures. After the collapse of Seongsu Bridge in 1994, Korea has enacted the "Special act on safety and maintenance of facilities" and secured the safety of facilities using systematic and periodic safety inspections. However, current facility inspections are mainly performed by the physical defect and structural analysis, and do not properly consider the serviceability of infrastructure such as capacity of facility and user's satisfaction. Thus, the purpose of the study is to develop an evaluation criteria for serviceability of infrastructures and finally leading to the revision of "Special Act on safety and maintenance of facilities in rational manner.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1652-1654
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• 1994

The Extra-high voltage XLPE cable is characterized by low transmission loss, large capacity, and high reliability. Conventionally, for XLPE cables of l54kV and above, aluminium sheath was used to be moisture barrier (thus preventing water tree deterioration of the insulation) and to protect cable core from physical stresses. However, as transmission capacity of the cable increases, so does the cable diameter and the corresponding aluminium sheath outer diameter and thickness. As a result, eddy-current loss in the sheath is increased, limiting the maximum current capacity of the cable itself. As an alternative to aluminium sheath, we have adopted stainless steel sheath with non-magnetic properties and a large resistivity, The new XLPE cable with stainless-steel sheath (CSZV cable) has drastically reduced eddy-current loss in the sheath.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.233-236
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• 2005

Sewage facilities are positively necessary for environment improvement such as rainwater removal, sewage disposal, preservation of the quality of water and health of the citizens in present-day. Meanwhile, a deterioration of the concrete sewer facilities is increasing rapidly due to the chemical and physical attack and especially biochemical attack that is to say biodeterioration. In this study, to prevent biochemical corrosion of the sewer concrete, surface of the concrete was spread with liquefied organic and inorganic complex antibiotics and then its engineering properties were experimentally investigated

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.13-17
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• 2004

In recent years, the deterioration of reinforced concrete structures has become a serious problem in civil engineering fields. This situation is mainly due to corrosion of steel reinforcing bars embedded in concrete. Recently, there has been a greatly increased demand for the use of FRP (fiber reinforced plastic) in civil engineering field due to their superior mechanical and physical properties. This paper presents an experimental study on the behavior of concrete bridge deck reinforced with FRP Box, FRP Plate, and FRP Re-bar. In tlIe study, mechanical properties of FRP Box, FRP Plate, GFRP Re-bar, and CFRP Grid have been investigated. Full scale one-way deck slab was tested under four point lateral load (equivalent to actual wheel load of DB-24 including impact). Load-deflection and load-strain data were collected through LVDT's and strain gages attached to the specimen.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.933-936
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• 2006

Many non-destructive inspection methods have recently been developed for concrete structures. However, these methods can obtain only physical information of concrete, such as crack depth, delamination or position of reinforcement etc. near its surface. If chemical information is required, sampling and componential analyses may be earned out. Non-destructive method that can detect deterioration factors such as carbonation, chloride content or sulfate attack would be an outstanding innovation in inspection methodologies. In this research, near-infrared spectroscopy and X-ray fluorescence analysis were applied for componential analysis for concrete. These methods are very effective compared to traditional methods, therefore, working efficiency and maintenance cost will be improved.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.553-556
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• 2006

Chloride penetration is the main reason which causes the deterioration of concrete structures. Chloride penetration of concrete structures due to chemical-physical phenomena can be profitably analyzed by means of model-based simulations. The main purpose of this paper is to analyze chloride penetration considering self-desiccation, convection and admixture(GBFS: granulated blast-furnace slag) effects. Basic governing equations are modified properly to apply these effects to chloride penetration analysis. Temperature and relative humidity data of In-Cheon from Korea Meteorological Administration are used for analyzing chloride penetration.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.187-190
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• 1998

The values of physical components of the plants and controllers as well as the relevant environmental conditions change in time, thus the output performance can be deteriorated during the operating span of the system. Naturally the duty of calibration or the prevention of performance deterioration due to excessive component sensitivity should be provided to the control system. The proposed controller, whenever necessary, measures the open-loop and close-loop characteristics, and then calculates the offset and sensor gain correction values based on the prepared standard measurements It is applied to the control of a flexible link system with the gain and offset calibration problems in the light sensor module for position to show the applicability. In this paper, we propose a digital controller which has the capability of calibration gain and offset adjustment using fuzzy methods.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.126-127
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• 2017

This study investigates the effect of improving the heat resistance performance when carbon fiber is mixed in the polyurea coating material. A tensile strength test method was carried out with the carbon fiber mixed polyurea specimens at an interval of 7, 14, and 21 days after heat treatment at 140±2℃. The test results showed that there was a significant decrease in the tensile strength performance. While the elongation and tensile performance decreased greatly, it was confirmed nevertheless the overall performance was maintained. This study proposes that mixing carbon fiber to the polyurea resin can effectively secure long-term heat resistance, thereby solving the problem of deterioration of physical properties caused by exposure to ultraviolet rays.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.109-109
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• 2015

댐의 건설은 하천의 흐름 및 지형학적인 부분에 큰 영향을 초래한다. 댐은 홍수조절효과로 인하여 큰 유량의 발생을 줄이지만 발전방류로 인하여 풍수량이상의 유량이 빈번하게 발생하게 되며, 또한 유사의 흐름이 단절되어 하류의 침식 및 장갑화를 초래한다. 이는 하천의 생태적인 측면에서 큰 영향을 끼치게 되므로 영향을 분석하고 피해를 줄이기 위한 연구가 필요하다. 기존의 연구는 발전방류로 인한 유량의 변동에 따른 물리서식처 변화를 중심으로 이루어져 왔으며 장기적인 하천의 지형의 변화로 인한 물리서식처 변화에 대한 평가는 미미한 상황이다. 본 연구는 댐의 발전 방류 시나리오를 수립하여 장기적으로 댐 하류에 미치는 영향을 알아보았다. 연구 대상지역은 낙동강의 지류인 내성천이며 상류에 영주댐이 완공될 예정이다. 대상 어종은 피라미로 선정하였다. 이를 위해 흐름 모형은 1D 부정류 모형을 사용하고 유사량 산정공식은 Wu et al.의 공식을 사용하였다. 서식처 분석은 HSI모형을 사용하였으며 대상 어종은 피라미로 선정하였다. 발전방류 시나리오를 수립하여 댐 건설이 하천의 하류에 미치는 영향을 분석 하고 발전방류 형태에 따른 물리서식처 모의를 실시하였다.

• Korean Journal of Human Ecology
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• v.6 no.2
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• pp.27-40
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• 2003

The Purpose of this paper was to study the uses of the extra activity classroom of elementary school and the satisfaction of the students. The SPSS 10.0 for windows was used to analyze data collected from 397 elementary school students in Kunsan and Seocheon. The results were as follows: (1) More than 2/3 students have experienced special activities. The extra activity classroom was not effectively used showing less than one or two hours use a week for the lecture and extra activities. (2) Generally the students were satisfied at the condition of extra activity classroom, but dissatisfied with the degree of the independence, of deterioration, and of safety while moving. That is because the building and its equipment were old, and soundproofing and safety establishments were not well equipped. (3) There was difference between schools. Students at city had more satisfaction than at county. (4) The most important item of extra activity classroom was esthetics followed by function, safeness. and healthiness. It shows that the important item is being moved to esthetics and healthiness from function of extra activity classroom.