• Smart Structures and Systems
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• 제4권5호
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• pp.641-653
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• 2008

This paper proposes a practical and realistic method to establish an optimal lifetime maintenance strategy for deteriorating bridges by considering the life-cycle performance as well as the life-cycle cost. The proposed method offers a set of optimal tradeoff maintenance scenarios among other conflicting objectives, such as minimizing cost and maximizing performance. A genetic algorithm is used to generate a set of maintenance scenarios that is a multi-objective combinatorial optimization problem related to the lifetime performance and the life-cycle cost as separate objective functions. A computer program, which generates optimal maintenance scenarios, was developed based on the proposed method using the life-cycle costs and the performance of bridges. The subordinate relation between bridge members has been considered to decide optimal maintenance sequence and a corresponding algorithm has been implemented into the program. The developed program has been used to present a procedure for finding an optimal maintenance scenario for steel-girder bridges on the Korean National Road. Through this bridge maintenance scenario analysis, it is expected that the developed method and program can be effectively used to allow bridge managers an optimal maintenance strategy satisfying various constraints and requirements.

• 한국고분자학회지:고분자과학과기술
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• 제6권1호
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• pp.28-40
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• 1995

• 한국컴퓨터정보학회논문지
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• 제22권3호
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• pp.69-79
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• 2017

In this paper, we propose our four-phase life cycle of P2P botnet with corresponding detection methods and the future direction for more effective P2P botnet detection. Our proposals are based on the intensive analysis that compares existing P2P botnet detection schemes in different points of view such as life cycle of P2P botnet, machine learning methods for data mining based detection, composition of data sets, and performance matrix. Our proposed life cycle model composed of linear sequence stages suggests to utilize features in the vulnerable phase rather than the entire life cycle. In addition, we suggest the hybrid detection scheme with data mining based method and our proposed life cycle, and present the improved composition of experimental data sets through analysing the limitations of previous works.

• KSBB Journal
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• 제30권4호
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• pp.175-181
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• 2015

Cells proliferate via repeating process that growth and division. This process is G1, S, G2 and M four phases consists. Monitoring the progression of the cell cycle is a specific step that to be a continuous process is repeated to adjust the start of the next step. At this time, this process is called a Checkpoint. Currently, there are three known checkpoints that G1-S phase, G2-M phase, and the M phase. In this study, we confirmed that cell cycle arrest effects by ethanol extracts of Artemisia annua Linne (AAE) in Hep3B liver cancer cells. AAE was regulated proteins which involved in cell cycle such as pAkt, pMDM2, p53, p21, pCDK2 (T14/Y15). AAE induced cell cycle arrest in G1 checkpoint through phosphorylation of CDK2. Akt and p53 upstream is inhibited by AAE and p53 activated by non-activated pMDM2, p53 inhibitor. Thereby, activated p53 is transcript to p21 and activated p21 protein is combined with Cyclin E-pCDK2 complex. Therefore, we confirmed that AAE-induced cell cycle arrest was occurred by p21-Cyclin E-pCDK2 complex by inhibition of pAkt signal. Because of this cell cycle can't pass to S phase from G1 phase.

• Computers and Concrete
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• 제25권2호
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• pp.167-179
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• 2020

Optimal design of structures against earthquake loads is often limited to reduce initial construction costs, while the cost induced to structures during their useful life may be several times greater than the initial costs. Therefore, it is necessary to consider the indirect costs due to earthquakes in the design process. In this research, an integrated methodology for calculating life cycle cost (LCC) of moment-resisting concrete frames is presented. Increasing seismic safety of structures and reducing human casualties can play an important role in determining the optimal design. Costs incurred for structures are added to the costs of construction, including the costs of reconstruction, financial losses due to the time spent on reconstruction, interruption in building functionality, the value of people's life or disability, and content loss are a major part of the future costs. In this research, fifty years of useful life of structures from the beginning of the construction is considered as the life cycle. These costs should be considered as factors of calculating indirect costs of a structure. The results of this work represent the life cycle cost of a 4 story, 7 story, and 10 story moment-resisting concrete frame by details. This methodology is developed based on the economic conditions of Iran in 2016 and for the case of Tehran city.

• 한국태양에너지학회 논문집
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• 제31권1호
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• pp.23-30
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• 2011

International cooperation to reduce greenhouse gas emissions is expected to provide a big crisis and a great opportunity at the same time for our industry that heavily consumes energy. To cope actively with the international environmental regulation, such as the Framework Convention on Climate Change, quantitative measurement of the volume of greenhouse gases emitted by various industries and quantitative prediction of the greenhouse gas emissions of the future are becoming more important than anything else at the national level. This study aims to propose the calculation process of carbon dioxide($CO_2$) emission for building in life cycle. This paper describes and compares 9 different tool for environmental load estimation with LCA. This study proposed the calculation process for quantitatively predicting and assessing $CO_2$ emissions during the life cycle of buildings based on the life cycle assessment(LCA). The life cycle steps of buildings were divided into the design/supervision, new construction, repair, renovation, use of operating energy in buildings, maintenance, and reconstruction stage in the life cycle inventory analysis and the method of assessing the environmental load in each stage was proposed.

• 한국고분자학회지:고분자과학과기술
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• 제6권1호
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• pp.22-27
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• 1995

• 한국태양에너지학회 논문집
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• 제24권4호
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• pp.55-63
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• 2004

The purpose of this study is to development of life cycle cost analysis methodology of HVAC system for decision maker. The results of this study are as follows; maintenance/management, equipment construction, planning/design, and demolition/sell phases (1) To develop the cost breakdown structure for LCC in HVAC system, this study apply the method of additional pertinent level, title, CBS number, block number and variable index. (2) LCC analysis order of HVAC system compose four phase. (3) Life cycle costing influence diagram can bring us to make the most efficient decision through a visual graphical diagram that is shown relationship among variables and that decision maker traces easily from life cycle cost analysis situation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 추계학술대회 논문집
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• pp.467-469
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• 2009

In this study, fatigue samples were prepared from cylinder head parts that are actually used in domestic (A) and foreign (B) automobiles; high-temperature, high-cycle, and low-cycle fatigue characteristics were then evaluated and compared. A study on the correlation between the microstructural factor and high temperature fatigue characteristic was attempted. The chemical compositions of the heat resistant aluminum alloys above represented A356 (A) and A319 (B), respectively. The result of the tensile strength test on material B at $250^{\circ}C$ was higher by 30.8MPa compared to material A. On the other hand, elongation was 8.5% higher for material A. At $130{\circ}C$, material B exhibited high fatigue life given high cycle fatigue under high stress, whereas material A showed high fatigue life when stress was lowered. With regard to the low-cycle fatigue result ($250^{\circ}C$) showing higher fatigue life as ductility is increased, material A demonstrated higher fatigue life. Through the observation of the differences in microstructure and the fatigue fracture surface, an attempt to explain the high-temperature fatigue deformation behavior of the materials was made.

• 정보관리연구
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• 제42권1호
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• pp.25-46
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• 2011

본 연구는 디지털 콘텐츠 수명주기 모델을 조사, 분석하여 핵심 수명주기 요소를 제언하고자 하였다. 또한 제언된 수명주기 모델을 현재 KISTI에서 운영 중인 디지털 콘텐츠 관리 절차와 비교하여 현재 디지털 콘텐츠 운영상에서 주요 문제점과 함께 개선사항이 무엇인지 도출하고자 하였다. 연구 결과 10개의 수명주기 요소 범주와 31개의 요소로 구성된 핵심 수명주기 요소가 제안되었으며, 현재 KISTI에서 서비스 중인 6가지 자료형태의 수명주기와 비교 분석한 결과 향후 KISTI에서 디지털 콘텐츠 아카이빙을 주요 임무로 설정하고, 체계적으로 성문화된 정책을 마련해야 할 필요성이 있음이 밝혀졌다.