• 한국시뮬레이션학회논문지
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• 제24권1호
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• pp.35-43
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• 2015

본 연구는 최근 정부의 주요 에너지 관련 정책 중 하나인 지능형 전력망 확산 사업 중 대규모 장비와 전기차, 충전사업 등 다양한 이해관계자가 얽혀있는 지능형 운송 서비스를 도입하는 데 대한 객관적 타당성을 검증하기 위한 방안을 제시하였다. 지능형 운송 서비스를 구성하기 위한 기본적인 사업 모형을 설계하고, 해당 사업에 참여하는 이해관계자를 정의하였으며, 전기차 이용에 따른 이해관계자간 상호 거래를 중심으로 경제성 분석을 위한 기준을 제시 하였다. 특히, 전기차 이용자와 충전사업자의 경우 전기차 보급 규모에 따른 경제성이 크게 달라지는 만큼 극단적인 두 보급 시나리오를 설계하여 각 이해관계자들이 수익 구조가 어떻게 달라지는 지를 비교 분석하였다. 분석 결과 초기 장비 투자비용에 대한 부담을 가진 전기차 이용자와 충전사업자의 경우 해당 사업에 참여하기 위한 경제적 타당성을 확보하기 어려운 상황인 반면 전기차 및 충전설비 공급자의 경우 일정 수준 이상의 수익을 보장받을 수 있을 것으로 예상되었다. 특히, 해당 사업의 추진과 지원의 책임을 가진 정부의 경우 전기차 보급에 따른 에너지 수입 비용 및 이산화탄소 배출 절감에 따른 편익 증가를 통해 전기차 보급 규모에 따라 타 이해관계자에 비해 높은 수익을 보장받을 수 있다는 점을 발견하였다. 따라서 전기차 이용자와 충전사업자에 대한 지원 비율을 일정수준 높일 필요가 있으며, 전기차 사용자와 충전사업자 간 이해가 상충되는 전기차대 충전설비 비율에 대한 다양한 시나리오 분석이 추후 수해되어야 할 것이다. 본 연구의 결과를 통해 향후 성공적인 지능형 운송 서비스 확산을 위해 필요한 사항을 개별 이해관계자 관점에서 확인하는 데 활용될 수 있을 것이다.

• 아태비즈니스연구
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• 제13권2호
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• pp.139-154
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• 2022

Purpose - This study aims to analyzing of solar power generation cost-benefit. Design/methodology/approach - We analyzed whether there is economic feasibility by selecting parking lots and idle sites located in four areas of Seoul, Gyeonggi, Chungcheong, Jeolla, and Gyeongsang areas nationwide, and analyzing site conditions and installation capacity. Findings - According to the results of the analysis, it was found that there is low profitability in Seoul, Gyeonggi and Chungcheong regions, where the solar radiation was not excellent even if REC is selected through the contract market. However, it is necessary to analyzed the economical validity the profitable validity including environmental benefits (greenhouse gas reduction, NOx, SOx reduction effect) and social benefits (renewable power supply) that is analyzed by income and operating costs which is occurred from electricity sales and REC sales when installing solar power generation facilities. Research implications or Originality - In this study, economic feasibility was evaluated additionally in consideration of environmental and social benefits. In conclusion, it was shown that businesses are not economical when considering only simple financial aspects are also sufficiently economical when it is considering environmental and social benefits.

• 한국철도학회논문집
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• 제8권5호
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• pp.444-453
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• 2005

The safety evaluations of railway wheelsets make use of the static fracture toughness obtained in ingot materials. The static fracture toughness of wheelset materials has been extensively studied by experiments, but the dynamic fracture toughness with respect to wheelset materials has not been studied enough yet. It is necessary to evaluate the characteristics of the fracture mechanics depending on each location for a full-scale wheelset for high-speed trains, because the load state for each location of the wheelset while running is different the contact load between the wheel and rail, cyclic stress in the wheel plate, etc. This paper deals with the fracture toughness depend on load rates. The fracture toughness depending on load rate data shows that once the downward curve from quasi-static values was reached, subsequent values showed a slow increase with respect to the impact velocity. This means that dynamic fracture toughness should be considered in the design code of the wheelset material.

• Journal of Biosystems Engineering
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• 제20권1호
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• pp.22-35
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• 1995

Pepper is the most important horticultural plant in Korean farm. Pepper harvesting has been known to be the most difficult process in pepper cultivation so that demand for mechanization is strong. In a research to develop a pepper harvesting machine performance and capacity of the harvester should be determined based on both economical feasibility and machine design concept. In order to accomplish an economical analysis of the pepper harvester, a mathematical model for comparing manual harvesting cost to machine harvest cost was developed. Validity of the model depends on the data used in the model. Economical information for the model variables was acquired from the result of farm survey on pepper cultivation technique and economics of pepper farmer. Technical information on pepper harvester were also collected through literature review and analyzed. Based on the economical analysis and synthesis of the technical information on pepper harvesters, its performance and capacity were determined. The operating performances of the harvester such as cutting, conveying, flipping, pepper removing and post-processing (sorting) were determined. Daisy capacity of the machine was determined to be 0.41 ha. A pepper harvester with the suggested capacity was economically feasible if the price of pepper harvester, pepper recovery ratio and service life of harvester were about 6 million won, 80%, and 4 years, respectively.

• 동력기계공학회지
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• 제9권2호
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• pp.106-111
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• 2005

After many casualties of conventional bulk carriers in recent years, a double hull bulk carrier was proposed to enhance the structural safety of a side shell and a transverse bulkhead. In this paper, two alternative structural designs of a double hull bulk carrier were carried out based on the Lloyd's rule. One has the double sided hull with longitudinal stiffeners and the other has that with a girder. The final structural design was examined in comparison with an existing single hull bulk carrier from the viewpoints of cargo hold capacity and the increases of weight and construction cost. Generally, the construction cost of a ship consists of the costs of material, labor and overhead cost. But, in this study, the relative construction cost concept was introduced to compare the economical validity more precisely. In this concept, fixed overhead cost is excluded in the assessment of construction cost, and only the variable overhead cost is added up to labor cost. As the result of this study, a double hull bulk carrier can be constructed within 1% increase of weight and construction cost.

• 조명전기설비학회논문지
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• 제23권9호
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• pp.31-39
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• 2009

본 논문에서는 경제성 평가를 기반으로 하는 배전 설비투자 우선순위를 결정하기 위하여 배전계통 구성, 설비 및 부하정보를 이용하여 배전계통을 모델링 하고, 현 계통의 신뢰도를 개선하기 위한 방향으로 설비투자 대안들을 설계한 다음, 이 대안들을 대상으로 신뢰도 및 경제성을 평가하는 모델을 제시하였다. 이러한 투자대안들의 신뢰도 영향과 경제성을 분석하기 위하여 한전의 주요 배전설비(15종)의 신도율(시변고장율)과 설비투자시 영향을 받는 고객들의 정전비용을 적용하여 경제적 효과를 산출하였으며, 이러한 투자 방법론의 유효성을 검증하기 위하여 한전의 배전사업소 실제 투자안을 대상으로 하여 경제성 평가를 수행한 결과와 비교분석하였다.

• 산업경영시스템학회지
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• 제41권4호
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• pp.111-122
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• 2018

The private sector is currently reviewing the feasibility of the project or deciding economic policies by analyzing the economic ripple effects. However, the arms acquisition project focuses on the need for the national defense weapons system by analyzing the costs and the effectiveness of the analysis and reviewing the necessity and feasibility of the project. In order to analyze the economic ripple effects, KB (the Bank of Korea) prepares and publishes an analysis table of industrial associations in a given unit. IAAR (the industrial association analysis report) is difficult to apply directly to the defense weapons system. Therefore, research on the economic ripple effects applicable to the defense arms procurement project was needed. In this study, we propose the generic methodology for estimating economical and technical ripple effects resulted in acquiring new weapon systems. Based on the analysis of inter-industrial relations, economical ripple effects are estimated with production inducing effects, value-induced effects, employment-induced effects and export-induced effects. Also, the technological ripple effects are estimated with technological intensity represented by investment cost in research and development. To show the validity of proposed methodology, a case study of acquiring new weapon systems such as GR (guided rocket), destroyer, and helicopter is accomplished. From the case study, it is concluded that these economical & technological ripple effects can be used as a reference to decision making in the course of acquiring major future defense weapons systems.

• 교육시설
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• 제12권5호
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• pp.47-56
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• 2005

Reports on population movement(2000-2030) by the National Statistical Office show that the number of elementary school age population will be decreased by 1.4million from 2005 to 2020. It will effect both school size and the policies for school facilities, which have focused on downsizing class as the high standard of OECD nations. As the unfolding evidence is emerging that a number of schools and classes will be emptied out by 2030. This study aims at developing a model for evaluating the validity of school establishment, which would help more reasonable decision-making for new school construction and the class extension in the existing schools. It classifies two different ways in founding a new school - school establishment in a residential developing site and school establishment for solving a overcrowd class. It proposes the assesment items and the methods for evaluating its validity. In the end, it suggests an assesment model which the district educational offices can use in the course of planning the student accomodations to schools and making decisions for new school construction and the class extension in the existing schools. This study would be expected to help the reasonable expenditure for school facilities and to restrict overbuilding of surplus classes.

• 대한간호학회지
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• 제43권1호
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• pp.59-68
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• 2013

Purpose: This study was done to develop the self-report Mother-Preschool Child Interaction Scale (MPIS) for mothers of preschool children. Methods: The scale was based on items derived from literature review and in-depth interviews. A methodological study was used to check reliability and validity and participants were 334 mothers of preschool children enrolled in kindergarten or nursery. Data were analyzed using principal component factor analysis for construct validity, t-test for contrasted group validity, Pearson correlation for criterion related validity and test-retest reliability and Cronbach's ${\alpha}$ for reliability. Results: In the final MPIS 34 items identified through factor analysis were included, 6 constructs were derived, and explanatory power was 64.2%. Items on the MPIS were verified through correlation with the interaction observation scale of Kim & Mahoney and MPIS. Results were significant as mothers in the normal group exhibited MPIS scores that were significantly higher than those of mothers in the depressed group. Reliability of MPIS was .96 and test-retest reliability was .92. Conclusion: MPIS has the advantage of being easy to use, economical, and useful. Consequently, it is expected to be used as a screening tool for promptly and simply identifying the mother-preschool child interaction in diverse nursing practice and research.

• 대한물리의학회지
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• 제10권2호
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• pp.1-7
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• 2015

PURPOSE: The aims of this study were to assess the intra-tester and inter-tester reliability and validity of hip range of motion using a smart phone in hip operative patients. METHODS: Twenty-five patients (eight total hip arthroplasty and seventeen femur neck fracture) participated in this study. The range of motions in active and passive hip flexion, abduction and external rotation were measured with a goniometer and smart phone over two times by two observers. The intra-tester and inter-tester reliability were evaluated using the intraclass correlation coefficient (ICC2,1). The validity was measured by Pearson's correlation coefficient RESULTS: The intra-observer reliability was good in all measured items (ICC>0.78). The inter-observer reliability was high with ICC (>0.90). All correlation coefficients of smart phone and goniometer was greater than 0.85 and showed a significant positive correlation (p<0.01). CONCLUSION: The range of motion measurement with a smart phone showed acceptable reliability. Therefore, it could be convenient and have economical benefits to measure the range of motion of the hip joint using a smart phone.