• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.101-111
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• 2013

In this study, DEA (Data Envelopment Analysis) was carried out on the four bridges, which have the same extension (L=1,615m), in order to select the most superior, economical method of construction using the LCC concept of each bridge structure in the case of the Ulsan-Pohang double track railway which is scheduled to be constructed. DEA models were analyzed with the CCR model, which was designed for the evaluation of relative efficiency of each model. The initial construction costs, maintenance costs, indirect costs (user costs + indirect loss of social costs), and life cycle costs were used as input variables, and average duration was applied as the output variable. LCC was applied to calculate the input variables, and to get the costs of LCC, 100 years of period and 4.83% of real discount rate were applied, and the costs are classified into initial construction, maintenance, user, and indirect loss of social cost. The analysis results showed that the Method 2 and 3 were evaluated as the most efficient, and the other alternatives were evaluated as the following order; Method 1, the default, and Method 4.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.216-220
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• 2012

본 연구는 경기도 용인시에 위치한 공공하수처리장을 대상으로 소수력발전 성능특성을 예측하고 경제성을 분석하여 소수력발전소의 건설타당성을 제시하였다. 방류구에서의 수준측량 조사에 따르면 실제 유효 낙차는 4.3m로 나타났다. 최근 5년간 방류량 자료를 살펴보면 일평균 실제 처리량은 약 $30,000m^3/day$로 나타났으며, 우수 유입과 물 사용량이 증가하는 여름 및 가을에 처리량이 증가하였다. 설계유량은 유량변화에 따른 누적 확률밀도와 유량지속곡선에 근거해 산정하였으며, 시간빈도로 보았을 때 17%의 유량이 지속되는 $0.35m^3/sec$가 설계유량으로 나타났다. 예상되는 수차 발전용량은 11kW급이며, 시스템 가동율은 74%, 그리고 계통선에 송출될 수 있는 연 전력생산량은 71.3MWh로 나타났다. 경제성 평가는 신재생에너지 경제성 분석 도구인 RETScreen 프로그램을 사용하여 B/C ratio, IRR, 개발투자비 등의 경제성 평가지표들을 산정하였다. 편익(Benefit) 산정시 전력기준단가는 133.67원/kWh, 할인율 7%를 적용하였으며, 비용(Cost) 산정시 유지관리비는 초기 건설비의 1%, 사용연한 30년을 적용하였다. 경제성 분석결과 기흥레스피아의 소수력발전소 건설시 초기 건설공사비가 $165,000 일 때, B/C 1.0, NPV $3,534, 투자회수기간 15.1년으로 산정되었고 따라서 초기 건설비용이 $165,000 이하일 때 가장 경제적인 것으로 파악되었다.

• Journal of the Korean GEO-environmental Society
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• v.24 no.11
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• pp.19-24
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• 2023

Ground anchor has been widely used specially for maintaining stability on reinforced cut slope in expressway. While the durability of the ground anchors should be ensured over the service life. However, the long-term loss of tensile force has occurred in most of field-installed anchors. Main causes are not clearly identified and very few studies have been made for analyzing long-term behavior of ground anchor in slopes. In this study, full-scale model tests and long-term measurements were made to obtain the load-displacement data and identified the causes of the long-term behaviors of ground anchor. As a result, the bond strength decreases exponentially with increasing water-binder ratio. Especially, groundwater is the most influencing factor to the bond strength. In the long-term behavior, the load decreases sharply until the initial settlement stabilized, and thereafter the tension force decreases constantly.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.293-300
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• 2012

This study was to investigate the unsuitable rate of the storage facilities, the changes in corrosion process over time after installation according to the status, the time to install the facilities, years elapsed after facilities installation, inspection of methods and motivation, and so on, based on the results of the inspection at the petroleum storage facilities conducted by domestic soil-relate specialized agency to derive optimal management plans which meet the status of soil contamination facilities. The results showed that the facilities more than 5 years after the initial leak test at the time of the installation need to be inspected periodically by considering costs of leak test and remediation of polluted soil. The inspection period can be decided by cost and leak test methods showing discrepancies for the results obtained from individual test whether it was direct or indirect. To compensate these matters, we suggested that the direct inspection method on regular schedule is recommended. On the other hand, the inspection can be voluntarily completed to ease burden of the results by inspection or equivalent level to this inspection method. Also, it may need improved construction supervision and performance test system to minimize the occurrence of the nature defects in installing the facilities as well as the upgrade program for the facilities during intervals of inspection period.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2005.05a
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• pp.47-55
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• 2005

Fire extinguisher, which is cost effective and easily accessible, is a very effective way of fire suppression. To keep its initial performance it needs periodical inspection and appropriate maintenance. However, many fire extinguishers of which the powder is incompletely coated deteriorates due to the moisture and leak of charge pressure after several years. Accordingly inappropriate powder replacement and pressurization has widely been doing by unqualified persons. Also, the absence of lifetime for fire extinguisher made people keep old bad fire extinguisher without precise inspection. This study specified those issues through case studies and suggested some ways for the systematic improvement.

• Analytical Science and Technology
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• v.6 no.4
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• pp.363-368
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• 1993

Blood lead concentrations of occupationally exposed workers were measured by the atomic absorption spectrometry with graphite furnace. The concentrations of the unexposed group were also checked and compaired with those of the exposed one. The correlation of smoking habit and work duration with the blood lead concentration was also surveyed.

• Journal of Korean Library and Information Science Society
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• v.38 no.1
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• pp.89-106
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• 2007

This is to present the information and direction about color scheme image and adjective image in designing web page, by analysing the color image of our country's National University library's web page which is being operated now. The analysis method is to find the RGB of objective site through color emotion standard and to abstract the color chip. It is divided by color scheme image and adjective image. The scope of research is 41 National University libraries registered in National University Libraries Association. The result is that white and grey color of background and colors like light blue and green are main. In case of adjective image, nimble image and clear image was many. next is orderly bellowing image. and elegant image.

• Science of Emotion and Sensibility
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• v.2 no.2
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• pp.1-10
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• 1999

본 연구의 목적은 중추신경계 반응과 자율신경계 반응을 이용하여 향이 인간에 미치는 영향을 평가하고자 하는 것이다. 본 연구는 20-26세의 남자 10명, 여자 10명으로 구성된 피험자를 대상으로 이루어졌고, 100% Rose oil bulgrian, Lemon oil misitano, Jasmine abs., Lavender oil france (KIMEX.co.ltd) 등 4가지의 향을 사용하여 실험을 수행하였다. 전두엽 (Fz)과 두정엽 (Cz)에서 EEG를 기록하여 대역별 relative power spectrum 값을 구하고 $\alpha$대역에 대한 $\beta$대역의 비($\beta$/$\alpha$)를 통하여 향에 대한 감성 평가를 시도하였다. 또한 자율신경계 반응은 심전도, 피부온도, 피부저항의 생리신호를 측정하였다. 주관적 평가는 향의 세부적인 이미지를 나타내는 후각 감성 형용사를 이용하여, 양극의 7점 척도 25문항, 단극의 5점 척도 40문항, 그리고 각 향의 전반적인 선호도를 묻는 양극의 7점 척도 2문항으로 구성하여 자극제시 전, 후에 각각 실시하였다. 전체적으로 피험자들은 Lemon을 가장 쾌하고 연하다는 평가를, Rose를 가장 불쾌하며 진하다고 평가하였다. $\beta$/$\alpha$의 비는 쾌하고 연할수록 감소하였고 불쾌하고 진할수록 증가하였다. 또한 심박 변화율과 피부온도는 쾌하고 연할수록 감소하였고, 불쾌할수록 반대 결과를 나타내었다. 결론적으로 쾌하고 연한 향과 불쾌하고 진한 향 사이에 $\beta$/$\alpha$의 비와 자율 신경계 반응의 차이를 관찰할 수 있었다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.638-641
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• 2006

In this paper, A calculating cost method of maintenance and repair for bridge which is built up by new construction technique named Up-Down Precast Concrete(UDPSC). After 2000, 109 Bridges which are using UDPSC technique have been built up, 37 bridges's construction work are processing, and 194 designs are presented for construction. Because this technology has developed recently, there are few field data for analyzing the maintenance and repair cost. Therefore, the maintenance and repair cost is computed using Construction and Transportation Ministry's guide line for computation and former research's data.

• Explosives and Blasting
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• v.22 no.3
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• pp.43-55
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• 2004

Use term of tower style construction exceeds recently. Accordingly, according to construction safety diagnosis result, achieve removal or Improvement construction. But when work removal, must shorten shut down time. Therefore, removal method of construction to use blasting demolition of construction is very profitable. Influence construction and equipment by blasting vibration and occurrence vibration caused by felling impact. Is using disadvantageous machine removal method of construction by and economic performance by effect of such vibartion. Therefore, this research studied techniques to forecast vibartion level happened at blasting demolition and vibration reduction techniques by use a scaled model test.