• 한국건설관리학회논문집
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• 제5권2호
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• pp.55-63
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• 2004

유지관리 분야는 다른 단계에 비해서 법과 제도가 미비하고, 관계기관 및 건축주가 이에 대한 대비가 충분하지 못하여 건축물의 수명이 물리적인 수명에 훨씬 미치지 못하는 경우가 많이 발생하고 있다. 또한 건설제단계의 Life-cycle을 고려하면 전체 공용수명 중 유지관리단계가 전체의 $70\%$가량을 점유하고 있어서 건설산업의 합리화를 위에서 유지관리에 대한 관리체계의 정립이 필요하다. 그리고 현재 운용 중인 유지관리 시스템은 주로 하자발생시 이를 처리하는 하자대응시스템으로 운영되고 있으며, 다른 단계와의 정보 공유는 낮은 수준에서 이루어지고 있다. 공동주택을 비롯한 건축물과 관련된 우리나라의 기존 제도, 법규 및 정책 등은 신규 건설시장에 초점이 맞추어져 있어서, 기존 시설물을 효율적으로 관리하기 위한 체계는 아직 제대로 정비되어 있지 않고 있다. 따라서 본 연구에서는 공공시설물의 효율적인 $운영\cdot관리\cdot활용$을 위하여 공공시설물 유지관리 체계의 현황을 분석하여 시스템의 구축방향을 제시하며, 나아가 정부주도로 구축되고 있는 건설정보 시스템을 구축에 대응하여, 현행 유지관리 정보시스템의 발전방향과 개선방향을 제시하고자 한다.

• 한국안전학회지
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• 제4권1호
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• pp.25-39
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• 1989

Cyclic temperature creep tests were carried out an AS 7075 alloy specimens were subjected to a constant load and stepwise temperature cycles in which temperature was fluctuated between 30$0^{\circ}C$ and 25$0^{\circ}C$ with three different cycle ratios. The highest frequency of cycling was 1 cycle per 10 hr and the lowest one was 1 cycle per 12 hr. From the creep experimental results with the above conditions the creep strain under cyclic temperature can be predicted easily by introd ucing the equivalent steady temperature because defined by Eq.(16), but the rupture life is 1.1 time than those of constant temperature because of effect of temperature history at tertiary creep range. Besides thlis result, the results of the creep test under cyclic temperature conditions are respectively compayiea with calculated rupture lives using the life fraction law and Eq.(18). The agreement between the obseried rupture times and calculated ones is fairly good. So creep rupture lives can be respectively predicted using life fraction law and Eq.(18).

• 소음진동
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• 제10권4호
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• pp.686-691
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• 2000

In this paper a computer aided analysis method is proposed for durability assessment in the early design stages using dynamic analysis, stress analysis and fatigue life prediction method. From dynamic analysis of a vehicle suspension system, dynamic load time histories of a suspension component are calculated. From the dynamic load time histories and the stress of the suspension component, a dynamic stress time history at the critical location is produced using the superposition principle. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The predicted fatigue life cycle is verified by experimental durability tests.

• 한국전자통신학회논문지
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• 제8권8호
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• pp.1161-1170
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• 2013

2013년 현재 개인정보보호를 위한 사회적 합의결과로 도출되어진 관련법이 제정되고 수차례의 개정을 통해 IT분야를 비롯한 다양한 사회적 업무분야에 최종적인 정보보호를 위한 명확한 성문법적인 정책과 지침 등의 방향이 제시되어 졌다. 이러한 일련의 개인정보 중요성에 대한 사회적 이슈를 기반으로 새로운 개인정보 접근 패러다임이 나타났고 정보보호라는 거시적인 접근 방법에서 전문적인 접근방법의 필요성이 대두되어졌다. 물론 현재까지 모든 개인정보 형태의 자료들을 특정한 정보의 범주에 모두 제한하고 경계를 두는 것은 다소 무리수 있어 보이나 IT분야를 기반으로 하는 정보의 홍수 속에서 개인정보의 흐름을 확인하고 보안대상으로 선정하는 부분은 표준화되어 진 것은 사실이다. 다만 아직까지도 개인정보 Life-Cycle의 5가지 표준화된 흐름인 수집, 처리, 제공, 보관, 파기 등을 모든 기업과 기관이 보유한 정보들에 일상적으로 적용하기 어려운 경우도 발생하고 있다. 따라서 이원화된 계층적 개인정보 Life-Cycle 접근제어 방법론을 제안함으로써 표준화 방법론을 제안한다. 본 연구결과는 개인정보 Life-Cycle에 최적의 접근제어 가능한 현실적인 자료를 제공하고자 한다.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.129-135
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• 1997

Previous studies has shown that the curve of low-cycle fatigue life was not expressed with the single line subjected to Manson-Coffin's law type and bent to short life in low ${\Delta}{\varepsilon}_p$ region. The main cause of this phenomenon has been considered that the localization of plastic strain in the crack initiation process fosters the crack initiation. In this study, the low-cycle fatigue life was investigated for each specimens omitted crack initiation process and it was found that fatigue life curve in log(${\Delta}{\varepsilon}_p$)-log($N_f$)was bent in low ${\Delta}{\varepsilon}_p$ region as ever. Therefore, the main cause of appearance of knee point in fatigue life curve is not found in the crack initiation process but in the crack propagation process. In the crack propagation process, the localization of the plastic strain in the vicinity of crack tip and the influence of test environment on the crack propagation rate were observed and these inclinations were more remarkable in low ${\Delta}{\varepsilon}_p$ region. Hence, it was concluded that these two phenomena in the crack propagation process were proved to the main cause which accelerates the crack propagation in low ${\Delta}{\varepsilon}_p$ region and bent the fatigue life curve in result.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1883-1888
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• 2000

In this paper a computer aided analysis method is proposed for durability assessment in the early design stages using dynamic analysis, stress analysis and fatigue life prediction method. From dynamic analysis of a vehicle suspension system, dynamic load time histories of a suspension component are calculated. From the dynamic load time histories and the stress of the suspension component, a dynamic stress time history at the critical location is produced using the superposition principle. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The predicted fatigue life cycle is verified by experimental durability tests.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2002년도 추계학술발표논문집
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• pp.228-233
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• 2002

In this study, Life Cycle Assessment method has been carried out the Corrugated board box in considering environmental aspects by quantifying the environmental emission and assessing its environmental impact potential. The system boundary in this study is selected from cradle to gate stage(raw material acquisition, raw material production and product manufacturing) of the paper product. To evaluate the environmental impact potential, impact categories are divided into 8 categories. As a results, abiotic resource depletion of the impact categories has the largest contribution to the total impact potential as 31.02% of total, Next were continued ecotoxicity having a contribution of 27.17%. In the life cycle, environmental impacts from law material production stage were contributed largely as 80.78%.

• Structural Engineering and Mechanics
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• 제35권5호
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• pp.571-592
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• 2010

An energy-based fatigue life prediction framework was previously developed by the authors for prediction of axial, bending and shear fatigue life at various stress ratios. The framework for the prediction of fatigue life via energy analysis was based on a new constitutive law, which states the following: the amount of energy required to fracture a material is constant. In the first part of this study, energy expressions that construct the constitutive law are equated in the form of total strain energy and the distortion energy dissipated in a fatigue cycle. The resulting equation is further evaluated to acquire the equivalent stress per cycle using energy based methodologies. The equivalent stress expressions are developed both for biaxial and multiaxial fatigue loads and are used to predict the number of cycles to failure based on previously developed prediction criterion. The equivalent stress expressions developed in this study are further used in a new finite element procedure to predict the fatigue life for two and three dimensional structures. In the second part of this study, a new Quadrilateral fatigue finite element is developed through integration of constitutive law into minimum potential energy formulation. This new QUAD-4 element is capable of simulating biaxial fatigue problems. The final output of this finite element analysis both using equivalent stress approach and using the new QUAD-4 fatigue element, is in the form of number of cycles to failure for each element on a scale in ascending or descending order. Therefore, the new finite element framework can provide the number of cycles to failure at each location in gas turbine engine structural components. In order to obtain experimental data for comparison, an Al6061-T6 plate is tested using a previously developed vibration based testing framework. The finite element analysis is performed for Al6061-T6 aluminum and the results are compared with experimental results.

• KEPCO Journal on Electric Power and Energy
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• 제7권2호
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• pp.241-248
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• 2021

High cycle fatigue life for the cables with two different types of clamps is estimated comparatively through acceleration testing. The high cycle fatigue fracture of overhead lines is caused mainly by the aeolian vibration which is induced by vortex shedding. It is necessary to manage the integrity of cables continuedly considering that the aeolian vibration is unavoidable since it occurs in steady and relatively low wind velocity. Two types of clamps which are largely used for overhead lines of the distribution grids are selected and failure data are obtained by step stress testing with a electrodynamic shaker with them. The inverse power law is assumed to describe the stress-life relationship and the fatigue limit at any specified life is supposed to follow Weibull distribution. The life of the cable is defined as the number of cycles to the time that one of strands is completely broken. Finally, the fatigue limits of the cables with two clamp types are estimated at the reference life of 500 Mcycles and compared each other based on a bending vibration amplitude.

• 교육시설 논문지
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• 제20권3호
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• pp.53-61
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• 2013

The purpose of this study is to suggest the way how to improve the school green building certification system based on life cycle assessment methodology and to assess $LCCO_2$ in outline. Green Building Certification System for School is comprised of 7 categories and 39 items. 7 categories include Land use and Transport, Energy and Atmosphere, Materials and Resources, Water, Management, Ecology, Indoor environmental quality. School is a public facility for students. So Green Building Certification System for School must have educational point of view adding to energy saving, reduction of greenhouse gas emission, etc. Also it needs to be classified into three categories ; kindergarten, elementar/middl/high school and university. Improvement plans for items are as follows ; energy consumption and $LCCO_2$ assessment considering life cycle, deletion or integration of duplicate items by comparing other systems, application of passive solar systems, consideration of the law and standards change, and selection of items considering specific building use.