• 콘크리트학회논문집
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• 제17권3호
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• pp.323-328
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• 2005

교량구조물은 설계당시에 설계기준에서 요구하는 구조적 안전성을 확보할 수 있도록 설계 및 가설된다. 그러나 시간이 지날수록 중차량이나 교통환경변화 등 여러 원인에 의해 손상을 받게되고 문제가 있는 교량은 결국에는 교체 또는 개선이 필요하게 된다. 본 논문에서는 기존 연구자료를 검토하여 교량의 유지관리조치를 수행하기 위한 의사결정과정에 영향을 미치는 인자를 파악하였고, 이를 이용하여 우선순위 산정 알고리즘을 제안하였다.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2008년도 춘계학술발표대회 논문집
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• pp.225-230
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• 2008

High-rise and high-density apartment complexes has been built and supplied on a large scale in the metropolis and metropolitan areas since 1980s in order to solve housing shortage in cities. Recently they are raising deterioration problems for aging more than 20 years. moreover, those problems show very special characters such as simultaneity and a large scale. The purpose of this study is to propose a direction for the development of the evaluating indicators to measure the level of deterioration of apartments. The level of deterioration of apartments can be evaluated by housing performance. In order to evaluate the deterioration comprehensively, the housing performance indicators should be developed on the social, economical, and physical dimension. This study analyzed the concept of the apartment deterioration and compared housing performance indicators through literature review. First of all, when considering various factors in the evaluation of the deteriorated apartments, such as evaluating ranges, attributes and dimensions, housing performance indicators should be structured with the hierarchical framework. Second, housing performance indicators evaluating the level of deterioration of apartments should include social, psychological, and cultural aspects of home environments in order to understand adequately the attitude of the middle class toward services that apartments provide. Third, in previous researches, most criteria have been developed and weighted based on only expert opinions regarding performance indicators. So, It is necessary to include residents' opinions in developing performance indicators since they can provide more practical and feasible aspects the experts could not experience or understand.

• 한국구조물진단유지관리공학회 논문집
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• 제25권5호
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• pp.114-126
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• 2021

본 논문은 국내·외 (미국, 영국, 일본, 한국)의 교량유지관리활동을 비교하였다. 교량은 물류 및 교통망에 있어 매우 중요한 역할을 하고 있다. 제한된 예산으로 시민에게 적절한 수준의 서비스를 제공하기 위해서는 효율적인 교량 유지관리 활동 (예, 점검 및 보수·보강)이 이루어져야만 한다. 1980년대 후반 급속한 경제 성장은 국내 사회기반 시설 증가로 이어졌고 교량의 개소수 또한 급속도로 증가 하게 하였다. 교량 증가와 함께 노후화 또한 최근 빠르게 진행되고 있으며 이러한 교량 노후화 속도는 교량 유지관리를 담당하고 있는 관리주체에게는 상당한 부담이 되고 있다. 다행이 이러한 과정을 이미 경험하고 있는 해외국가의 체계적이고 종합적인 교량 유지관리 체계는 국내 유지관리 체계에 상당한 시사점을 줄 수 있을 것이라 판단하다. 따라서, 본 연구의 목적은 교량유지관리 선진국 (예, 미국, 영국, 일본)에서 시행되고 있는 교량 유지관리활동을 비교 분석하여 국내 유지관리에 시사하는 점을 분석하였다.

• 조명전기설비학회논문지
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• 제29권3호
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• pp.61-68
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• 2015

When medium and large induction motors are driven by 2-level inverters with low switching frequency, induction motors provoke deteriorated performances resulted from large torque ripples, flux ripples, and large current distortion. Model predictive torque control(MPTC) for a fast torque control of induction motors is also suffered from large torque ripples when the induction motors are fed by 2-level inverters that are based on 6 active voltage vectors with low switching frequency restricted. To solve this problem, this paper proposes a new MPTC method based on both a 12 active voltage vector and an optimized duty ratio calculation. The proposed control strategy illustrates its effectiveness under the various operating conditions through simulation works.

• 한국전산유체공학회지
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• 제9권3호
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• pp.26-38
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• 2004

A study has been made for the investigation of the robustness and convergence of various implicit operators of the LU-SGS scheme using linear stability analysis. It is shown that the behavior of the implicit operator is not determined by its own characteristics, but is determined relatively depending on the dissipative property of the explicit operator. It is also shown that, as the dissipation level of the implicit operator increases, the robustness of the scheme increases, but the convergence rate can be deteriorated due to the excessive dissipation. The numerical results demonstrate that the dissipation level of the impliict operator needs to be higher than that of the explicit operator for computing stiff problems.

• 한국물환경학회지
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• 제23권5호
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• pp.628-635
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• 2007

As the hydrologic cycle is transformed by the expansion of impermeable area as a result of the urbanization, the function of an ecosystem is deteriorated by the transformed hydrologic cycle. In this study, a SWMM code was modified to have a groundwater pumping option about rivers-aquifer interaction to be possible. The modified SWMM was applied to continuous simulations of urban runoff from Hakuicheon watershed and it was used to analyse the effect of a groundwater pumping. The modified SWMM overcame the limitation of the ground subroutine that it only simulate groundwater inflow from ground to rivers. The result of continuous simulation of groundwater pumping is that surface runoff, groundwater runoff and groundwater level are well simulated, and Modified SWMM expressed groundwater runoff by negative number (-) when groundwater level is less than river stage.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.170-171
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• 2016

The unity of korean peninsula have traditionally been established as major policy in korea government. Present government also set Trust Process on the Korean Peninsula as national high-level strategies for unity, and construction field related directly to living of north korean as major industry which would be implemented in early stage. Deterioration level of architectural facilities in north korea is known as very high, so a huge budget would be required to improve aging architectural facilities for stability of social and living of north korean. Therefore the purpose of this study deduct financing plan for improving aging architectural facilities in north korea and selection of optimal alternative securing effectiveness. The results of this study could be utilized as preliminary data for establishment of master plan and policy for improving deteriorated facilities in situation of united korean peninsula.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.558-563
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• 2004

Experiments were performed to see the effect of radial tip clearance on a turbopump inducer, which has two blades with inlet tip blade angle of 7.8 degree and tip solidity of 2.7. Hydraulic and cavitation tests were done for three cases of tip clearance ratio, that is, 0.026, 0.053, and 0.079. With increase in the tip clearance, inducer head and pressure on the inducer tip decreased. Attached cavitation and cavitation surge were found in the cavitation tests. In the attached cavitation one cell rotated at the same rotational speed as that of the inducer. Cavitation performance deteriorated with increase in the tip clearance. The level of casing vibration increased in the cavitation condition and the level was very high when the attached cavitation appeared.

• Asian-Australasian Journal of Animal Sciences
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• 제29권2호
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• pp.263-270
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• 2016

This study was conducted to investigate the effects of raw material ratio on the physicochemical characteristics of emulsion-type pork sausages. Experiment design was divided into 12 treatments, based on protein level (P), fat level (3P, 3.5P, and 4P), and water level (4P+10, 4P+15, 4P+20, and 4P+25). The pH and shear force values were significantly higher in T7 (3.5P fat and 4P+20 water) than those of other treatments. The lightness and redness were greatly reduced by increasing the quantity of water. The treatments containing 3P fat and 4P+20 water had the highest values of cohesiveness, springiness, gumminess, and chewiness. On the whole, when the protein (P) and fat (3P, 3.5P, 4P) levels were fixed, an increase over the appropriate moisture level deteriorated many physicochemical characteristics.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.223-228
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• 2005

Precast concrete deck has many advantages comparing with the in-situ concrete deck, and has been successfully applied to replacement of the deteriorated decks and to the newly constructed highway bridges in domestic region. In order to apply the precast decks into the railway bridges, however, differences of the load characteristics between the highway and the railway should be properly taken into account including the train load, longitudinal force of the continuous welded rail. acceleration or braking force, temperature change and shrinkage. Proper level of the longitudinal prestress of the tendons that can ensure integrity of the transverse joints in the deck system is of a primary importance. To this aim, the longitudinal tensile stresses induced by the design loads are derived using three-dimensional finite element analyses, design codes and theoretical equations for the frequently adopted PSC composite girder railway bridge. The estimated proper prestress level to counteract those tensile stresses is over 2.4 MPa, which is similar to the case of the highway bridges.