• 한국태양에너지학회 논문집
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• 제39권5호
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• pp.53-63
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• 2019

This paper in order to efficiently operate zero energy buildings developed a methodology for optimal operation of PV + ESS active systems. This program consists of three steps. First step is PV optimal operation and second step is PV + ESS optimal operation. Third step is the analysis of the results by PV + ESS optimal operation. The optimal operation of PV + ESS was calculated by using Dynamic Programming (DP). Therefore, the optimal capacity and operating plan of PV + ESS in this study are calculated for electric load at building. This paper conducted case study to verify the validity of the developed algorithm. Also, the sensitivity analysis analyzed the effect of each variable on the optimal operation.

• 대한영양사협회학술지
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• 제6권1호
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• pp.33-43
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• 2000

Environmental pressures from such sources an economic condition, the government and inter-institutional competition create managerial challenges. Economic pressures may be forcing dietetic dept, in hospital to utilize cost∙benefit analysis to assist them in their problem solving. Cost∙benefit analysis have been widely used in business, industry and many other fields with only limited application to foodservice. Due to the lack or this information the purposes of this study were to identify use of cost∙benefit analysis in hospital foodservice system to evaluate the economic efficiency of alternatives, and to make recommendation for operation system change. Using the cost∙benefit method, cash flows are separated into cost and benefits. For an alternative to be selected, indicators, such as NPV, benefit-cost ratio (B/C ratio) with 5% discount rate per annum. The sensitivity analysis was also conducted with difference rate 3%, 7% respectively and reduced employee payroll change. The result of this study can be summarized as follows : 1. The total cost of investment for operation system change was 390,570 thousand won and the total benefit through operation system change was 865,808 thousand won. 2. Net present value(NPV) for 5 years was 475,239 thousand won and benefit-cost ratio was 2.22. 3. In sensitivity analysis with different discount rate 3%, 7%, benefit-cost ratio was 2.25, 2.18 respectively, with total reduced employee payroll change, benefit-cost ratio was 2.86. In conclusion, total benefits were exceeded total costs. Therefore, the project of operation system change in hospital foodservice was found to be economically efficient.

• 상하수도학회지
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• 제25권6호
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• pp.885-892
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• 2011

In this study, LCA(Life Cycle Assessment) on 'Saemangum CSO Project' was carried out to evaluate environmental impact which occurred during the construction and operation periods and the potential environmental impact reduction was analyzed by comparing production and reduction level of pollution loads. LCA was conducted out according to the procedure of ISO14040 which suggested Goal and Scope Definition, Life Cycle Inventory Analysis, Life Cycle Impact Assessment and Interpretation. In the Goal and Scope Definition, the functional unit was 1 m3 of CSO, the system boundary was construction and operation phases, and the operation period was 20 years. For the data collection and inventory analysis, input energies and materials from civil, architecture, mechanical and electric fields are collected from design sheet but the landscape architecture field is excepted. LCIA(Life Cycle Impact Assessment) was performed following the procedure of Eco-Labelling Type III under 6 categories which were resource depletion, eutrophication, global warming, ozone-layer destruction, and photochemical oxide formation. In the result of LCA, 83.4% of environmental impact occurred in the construction phase and 16.6% in the operation phase. Especially 78% of environmental impact occurred in civil works. The Global warming category showed the highest contribution level in the environmental impact categories. For the analysis on potential environmental impact reduction, the reduction and increased of environmental impact which occurred on construction and operation phases were compared. In the case of considering only the operation phase, the result of the comparison showed that 78% of environmental impact is reduced. On the other hand, when considering both the construction and operation phases, 50% of environmental impact is increase. Therefore, this study showed that eco-friendly material and construction method should be used for reduction of environmental impact during life cycle, and it is strongly necessary to develop technology and skills to reduce environmental impact such as renewable energies.

• 한국콘텐츠학회논문지
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• 제20권12호
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• pp.287-300
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• 2020

본 연구는 노인복지관이 운영하는 실버 오케스트라 프로그램의 실천적 개선 방향을 도출하기 위하여 운영 속성에 대한 중요도-만족도 분석(IPA)을 수행하였다. 우리나라의 춘천동부노인복지관이 운영하는 '춘천 실버 오케스트라' 프로그램을 대상으로 실버회원 그룹(N=53)과 프로그램 운영자 그룹(N=32)을 조사 대상자로 선정하였다. '지역사회와의 연계', '예산 운영', '프로그램 운영', '인력 운영', '홍보전략', '프로그램 운영환경'을 포함하는 6개의 평가영역으로 구성된 평가지표를 설계하였다. 그리고 평가영역에 대하여 22개의 평가항목을 구성하였다. 본 연구의 결과, 실버회원 그룹에서는 '인력 운영'이 중요도와 만족도에서 가장 높은 우선순위를 가지는 것으로 나타났다. 프로그램 운영자 그룹에서는 '예산 운영'과 '인력 운영'이 중요도와 만족도에서 각각 가장 높은 우선순위를 차지하였다. IPA 매트릭스 분석을 통하여 나타난 연구 결과를 기반으로, 성공적인 프로그램 운영을 위해서는 실버회원 그룹과 프로그램 운영자 그룹의 관점에서 현상유지 및 강화, 집중투자 및 개선, 낮은 우선순위, 그리고 과잉노력 지양으로 영역화된 프로그램 운영 속성에 대해서 서로 차별화된 노력과 관심을 지속적으로 가져야 한다는 시사점을 제공한다.

• 한국항행학회논문지
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• 제28권4호
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• pp.518-523
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• 2024

드론의 폭발적 수요 증가로 인하여 저고도 공역에서 운항하고 있는 기존 항공기 및 국가 중요시설 안전에 큰 위협을 초래하고 있다. 저고도 공역 드론 안전위협의 종류 및 정도를 판단하기 위하여 각 분야의 항공종사자를 대상으로 저고도 공역 운항시 드론으로 부터의 위협 종류 및 형태를 AHP (analysis hierachy process) 분석을 통하여 가중치를 평가하고자 한다. 드론으로부터의 위협요소 계층도 구성은 항공선진국인 유럽 항공안전기구 (EASA)에서 선행 연구된 특정 운영 위험평가 SORA(specific operation risk assessment process) 기법을 활용하여 설계하였다. 이를 바탕으로 각 항공기 운항 및 임무수행간 사전 위해요인을 식별 제거함으로써, 기존 항공기들의 저고도 안전 운항을 확보할 수 있을 것이다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.199-204
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• 2000

A low temperature differential model stirling engine is manufactured, and its operation characteristics are measured and analyzed by SIMPLE analysis model, in which heat transfer processes are simply considered. The heat transfer coefficients between working fluid and heat sources in the analysis are estimated by comparing the P-V diagrams by experiment and by analysis. This result may be very useful for further design and manufacture of model Stilting engines as well as real engines because it provides a comparatively correct predictions of the operation conditions and power output. It will be also conveniently used as an educational material for mechanical engineering students because it can be a nice example of optimal design process to decide the phase angle and compression ratio of engine design with a simple but realistic simulation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.381-385
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• 2006

This research introduces easy tool manufacturing method regarding tool manufacturing procedure. In the conventional method, wire cutting machining and lapping operation of corner and render region were performed after shrink-fitting to ensure the accuracy of gear profile. But lapping operation is very difficult due to corner and render is located deep inside of die. In this research, wire cutting operation was performed after $1^{st}$ ring was shrink-fitted to ease lapping operation and increase the accuracy of corner radius. Before $2^{nd}$ ring fitting, lapping was completed. Elastic deformation amount due to $2^{nd}$ ring fitting and cold forging was calculated through finite element analysis and wire cutting specification was offset in that amount. Comparison of gear dimension between analysis and forged part ensures the validity of new manufacturing methods.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.636-641
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• 1998

In this paper, operation characteristics of the Zero-voltage-Switching(ZVS) mode and Non-Zero-Voltage-Switching (NZVS) mode of the active clamp (ACL) forward converter are compared through the loss analysis. The losses of semiconductor devices, transformer and passive elements of the converter are analyzed and compared for each type of operation mode. In order to verify the validity of the analysis, we have built a 50W ACL forward converter and measured the losses of the converter. From the experiment it is known that the ACL forward converter shows nearly same loss distribution for both of operation modes

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.173-175
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• 2013

In tall building construction, the equipment operation plans have an effect on productivity. Equipment, used in tall building construction, has operating plans of each it and restrictively operate owing to the first placed equipment operation. Therefore the interference of equipment was occur frequently. As it, the productivity is less effective and the construction delay occurs. This research was analysis the interference elements between the equipment for constructing the efficient equipment associated operational processes. The interference elements between the equipment derive through expert advice and analysis using IPA. Through the IPA, this research deducted the interference elements located 'Concentrate Here' which is the highest importance and the lowest performance.

• 전기학회논문지P
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• 제57권4호
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• pp.383-387
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• 2008

This paper analyzes the operation characteristics of a self excited induction generator with Steinmetz connection. For this analysis, the symmetrical components analysis is used to obtain the related expressions and the excitation capacitance and the magnetizing reactance are determined in turn by the condition of self excitation which includes the input impedance of the generator as viewed across load terminals. Two simultaneous equations of the condition of self excitation itself are solved by using the real and imaginary function in an application software. This method is applied to simulate the operation characteristics when the generator is driven at rated speed and the specified excitation capacitor is connected across the lagging phase. The results show that better operation characteristics except generated frequency are obtained by using relatively large excitation capacitance and resistive load.