• 한국농공학회논문집
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• 제53권3호
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• pp.59-64
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• 2011

The objective of the study is to develop life cycle inventory (LCI) database of dam, a major facility for irrigation water supply. The types of database developed are three out of nine dams according to the size of the wate r storage capacity: two kinds larger than 500,000 $m^3$ depending on gate for discharging (Type 1) and the other dam smaller than 500,000 $m^3$ (Type 2). According to the LCI analysis, type 1 larger than 500,000 $m^3$ storage capacity with gate has the lowest environment impact in the 6 impact categories. The impact of the type 1 accounts for 7~35 % of the type 2 for supplying irrigation water. Comparing with the environment impacts of water for other uses such as drinking and industrial water, the impacts of 1 $m^3$ irrigation water supply is 4~45 % of the one for industrial water supply and 1~16 % of the drinking water's. The three types of LCI DB on the irrigation water by dams will be useful in the application of Life Cycle Assessment in agricultural products and environmental labelling including carbon footprint since it is complied to the guidelines of LCI DB constr uction issued by Ministry of Environment and Ministry of Knowledge Economy.

• 한국도로학회논문집
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• 제17권2호
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• pp.143-150
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• 2015

PURPOSES : The authors set out to estimate the related carbon emissions, energy use, and costs of the national freeways and highways in Korea. To achieve this goal, a macro-level methodology for estimating those amounts by road type, road structure type, and road life cycle was developed. METHODS : The carbon emissions, energy use, and costs associated with roads vary according to the road type, road structure type, and road life cycle. Therefore, in this study, the road type, road structure type, and road life cycle were classified into two or three categories based on criteria determined by the authors. The unit amounts of carbon emissions and energy use per unit road length by classification were estimated using data gathered from actual road samples. The unit amounts of cost per unit road length by classification were acquired from the standard cost values provided in the 2013 road business manual. The total carbon emissions, energy use, and cost of the national freeways and highways were calculated by multiplying the road length by the corresponding unit amounts. RESULTS: The total carbon emissions, energy use, and costs associated with the national freeways and highways in Korea were estimated by applying the estimated unit amounts and the developed method. CONCLUSIONS: The developed method can be employed in the road planning and design stage when decision makers need to consider the impact of road construction from an environmental and economic point of view.

• Steel and Composite Structures
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• 제33권6호
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• pp.777-792
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• 2019

This paper presents a new efficient approach to estimate the S-N type fatigue life assessment curve for S550 high strength steels under low-cycle actions at -60℃. The proposed approach combines a single set of monotonic tension test and one set of fatigue tests to determine the key material damage parameters in the continuum damage mechanics framework. The experimental program in this study examines both the material response under low-cycle actions. The microstructural mechanisms revealed by the Scanning Electron Microscopy (SEM) at the low temperature, furthermore, characterizes the effect due to different strain ratios and low temperature on the low-cycle fatigue life of S550 steels. Anchored on the experimental results, this study validates the S-N curve determined from the proposed approach. The S-N type curve determined from one set of fatigue tests and one set of monotonic tension tests estimates the fatigue life of all specimens under different strain ratios satisfactorily.

• 대한가정학회지
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• 제30권1호
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• pp.237-255
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• 1992

The purpose of this study was to investigate relations of resources and demands, family financial management and financial statement of urban households by applying a system approach. The results of this study were as follows; Saving rate had significant differences according to resources variables such as age, family life cycle, occupation of househead and housewife, ratio of employed to family member, and to demands variabels such as subjective prospect of business cycle, and value orientation, whereas total saving amount had significant differences according to resources vaiables such as age, family life cycle, educational level, percapita income, occupation of househead, type of income and to demand variable, perception of relative income. Also average monthly saving amount had significant differences according to resources vaiables such as educational level, per capita income, occupation of housewife, housing ownership, ratio of employed to family member, ratio of dependent to employed, and to demands variable, perception of relative income. The stocks had significant differences according to resources variables such as age, family life cycle, educational level, per capita income, occupation of househead, type of income, and housing ownership. Finally, real estate had significant differences according to resources variables such as age, family life cycle, educational level, percapita income, occupation of househead, type of income, housing ownership, and to demands variable, perception of relative income. Financial Statement among urban households according to family financial management had significant differences. And among all variables affecting financial statement among urban households, per capita income had the highest effect and perception of relative income was the second.

• 기술혁신연구
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• 제2권1호
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• pp.256-276
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• 1994

This paper aims at identifying the desirable R'||'&'||'D life cycle related to government-industry cooperative R'||'&'||'D. It is based on a case study associated with the relationship between cooperation and cooperation in information in information communications sector. It presents three types of R'||'&'||'D life cycle to achieve a technological enhancement as high as possible with limited resources. The first case of R'||'&'||'D project is of "advanced type". In the generic technology phase, government takes a leading role jointly in R'||'&'||'D activities, but, in after the applied research phase, the domestic firms take the lead. This kind of cooperation can be made when competition between domestic firms is highly intense, and the technological knowledges of participating firms are at internationally competitive levels. The second type of "less-advanced type"; the firms of a country(more often a small country) lag behind in technology level, and the penetration of foreign firms in the market is limited. In this case, government takes full charge of R'||'&'||'D activities up to the applied research phase, due to the low technology level and insufficient financial resources of private firms. Lastly, this paper presents and R'||'&'||'D life cycle of "strategic" type. This applies to the case in which domestic firm with less financial resources make an attempt to increase their technological knowledges while the government, in turn, contributes to strengthen the international competitiveness of domestic industry.

• 한국안전학회지
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• 제24권5호
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• pp.48-56
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• 2009

This paper presents the procedure for the optimal design of a PSC-I girder bridge considering life cycle cost (LCC). The load carrying capacity curves for the concrete deck, PSC-I girder and $\pi$-type pier were derived and used for the estimate of service lives. Total life cycle cost for the service life was calculated as sum of initial cost, damage cost, maintenance cost, repair and rehabilitation cost, user cost, and disposal cost. The advanced First Order Second Moment method was used to estimate the damage cost. The optimization method was applied to the design of PSC-I girder bridge. The objective function was set to the annual cost, which is defined by dividing the total life cycle cost by the service life, and constraints were formulated on the basis of Korean Standards. The optimal design was performed for various service lives and the effects of design factors were investigated.

• 정보관리학회지
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• 제35권2호
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• pp.115-139
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• 2018

재난 웹 기록물의 가치와 보존의 중요성으로 인해 전 세계적으로 재난 아카이브의 구축은 국가적인 과제가 되어가고 있다. 본 연구는 재난 아카이브의 웹 기록물 수집에 있어서 이슈 생존 주기 모형에 기반한 수집 방안을 제시하는 것을 목적으로 한다. 이를 위해 먼저 국내외 재난 아카이브의 웹 기록물 수집 현황, 수집 방법 및 기간에 대하여 분석하였다. 또한, 최근 10년간 발생한 재난 이슈를 수집 및 분석하여 이슈 생존 주기 모형을 도출하였다. 이슈 생존 주기 모형은 재난의 특성에 따라 돌발형 및 주기형으로 구분되며, 각 모형에 따른 웹 기록물 수집 방안을 제시하였고 적용 가능성을 검증하였다.

• 한국치위생학회지
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• 제17권5호
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• pp.889-898
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• 2017

Objectives: This study was conducted in order to identify the various influencing factors of dental caries according to the socio-economic characteristics and oral health behaviors across the life cycle among Koreans. Methods: The data were extracted from the 6th Korea National Health and Nutrition Examination Survey (2013-2015) and a total of 4,871 subjects with ages of 7 and over were selected. The data were analyzed using SPSS 21.0 for ${\chi}^2$-test and multi-logistic regression. Results: Significant differences were observed in the socio-economic characteristics, health behaviors and in the dental caries across the life cycle. The influencing factors of DT includes the type of health insurance (p<0.05) in school aged & adolescence, Oral health examination/year (p<0.01), Residence (p<0.05) in early adults, type of health insurance (p<0.001), Oral health examination/year (p<0.001), use of oral hygiene products (p<0.01) in late Adults, Oral health examination/year (p<0.05) and Gender (p<0.05) in old age. Conclusions: This study suggests that dental health promotion can be enhanced by regular checkup. The government must provide the people with better quality of oral health care and promotion across the life cycle in the near future.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1709-1716
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• 2003

Stirling engine is a heat engine with a high potential efficiency, multi-fuel capability, its low emission, quiet operation, very low maintenance requirement and long life. The Stirling cycle can ideally achieve optimum thermodynamic efficiency of the Carnot cycle. But the actual efficiency of practical reciprocating Stirling engine is much less than that of ideal Stirling cycle due to several mechanical limits. This paper presents a new-type Stirling engine employing the scroll mechanism superior to the reciprocating Stirling engine. The new-type Stirling engine is characterized as traits of continuous and wholly seperated compression and expansion, one-way flow, direct cooling and heating through the extensive surfaces of scroll wraps. By means of this traits, the new-type Stirling engine can achieve thermodynamic cycle closer to the ideal Stirling cycle and have many mechanical merits. Also, the new-type Stirling cycle can be applied as Stirling refrigerator and Duplex Stirling machine.

• 한국건설관리학회논문집
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• 제15권6호
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• pp.35-43
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• 2014

최근 국토교통부에서는 무분별한 재건축, 재개발로 인한 사회적 비용을 감소시키고 주택의 수명을 늘리기 위해 장수명 공동주택의 도입을 촉구하고 있다. 장수명 공동주택은 기존 아파트 건설에 적용되는 벽식 구조와는 달리 기둥과 보가 연속적으로 이루어진 구조이기 때문에 내구성, 가변성, 유지관리 및 리모델링 용이성 등의 장점을 갖는다. 그러나 장수명 공동주택의 경우 기존의 벽식 구조방식의 주택에 비해 초기 투자비가 다소 상승하는 문제가 있는데, 이는 장수명 공동주택의 보급 확산을 저해하는 요소로 작용하고 있다. 이에 본 연구에서는 건물의 총 생애주기 관점에서 기존의 벽식 구조 공동주택과 장수명 공동주택의 경제성을 비교 분석하였다. 연구 결과 장수명 공동주택의 경우 일반 벽식 구조 공동주택에 비해 초기 신축미용은 약 18% 정도 증가하지만, 50년간의 총 생애주기비용을 산정해보면 벽식 구조 공동주택에 비해 약 7% 정도 경제적인 것으로 나타났다. 즉, 장기적인 측면에서 볼 때 장수명 공동주택의 도입이 경제적 사회적 측면에서 충분히 이점이 있음을 알 수 있었다.