• KIEAE Journal
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• 제15권3호
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• pp.57-63
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• 2015

Purpose: Ground source heat pump system has been attracted in the horticulture industry for the reduction of energy costs and the increasing of farm income. Even though it has higher initial costs, if it uses in combination with heat storage, it is able to reduce the initial costs and operate efficiently. In order to have significant effect of heat storage type ground source heat pump system, it is required to design the capacity considering various conditions such as energy load pattern and operating schedule. Method: In this study, we have designed heat storage type ground source heat pump system in 5 cases by the operating schedule, and examined the system to find the most economic and having superb performance regarding the system COP(Coefficient of Performance) and energy consumption, using dynamic energy simulation, TRNSYS 17. Result: Conventional ground source heat pump system has lower energy consumption than heat storage type, but following the result of LCC(Life Cycle Cost) analysis, the heat storage type was more economic due to the initial costs. In addition, it has the most efficient performance and energy costs in the case of the smallest heat storage time.

• 해양환경안전학회지
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• 제16권2호
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• pp.229-234
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• 2010

최근 온실가스 감축을 위한 세계 각국의 노력이 다각도로 진행되고 있으며, 국제적인 협력 또한 시급히 요구되고 있다. 이러한 노력의 일환으로 해운 업계에서는 항내에서 유발되는 선박 기인 온실가스 배출량 중 탄소에 대한 배출량 감축과 선박운항 비용 절감을 위한 친환경 항만 체계 구축 방안이 활발히 논의되고 있다. 이 논문에서는 탄소 배출량 감축 및 친환경 항만 체계 구축의 기초 연구로 정박 중인 선박에 자체 생산 전력을 공급하는 대신 육상전력을 공급하는 방안을 모색하였다. 이를 위하여 실제 운항중인 목포해양대학교의 실습선 새누리호를 대상으로 정박 중인 선박이 육상전력을 사용함으로써 얻을 수 있는 환경적 비용적 효과에 관해 고찰하였다. 연구 결과 육상전력을 사용한 경우에 $CO_2$ 배출량은 약 32.5%가 감소되었고, 운항비용은 약 33%가 절감된 것으로 나타났다.

• 대한교통학회지
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• 제23권3호
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• pp.85-94
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• 2005

물류시스템의 규모 및 운영상태는 물류시설에서의 화물차량 도착특성 및 하역서비스 능력에 의해 결정되는 교통강도(TI: Traffic Intensity)의 변화에 따라서 민감하게 변화된다. 구체적으로, 물류시스템 운영에 있어서 주요결정요인이 되는 교통강도는 연구 대상기간에 따라 변동되고 교통강도의 작은 변동에 의해서도 물류비용의 변화폭이 상당히 크다고 밝혀져 있다. 그러나, 현재의 물류시스템을 운영함에는 이러한 사항들이 고려되지 못하고 있다. 따라서, 본 연구에서는 물류시설을 운영함에 따라 불필요하게 발생할 수 있는 초과물류비용이 최소가 되도록 하는 최적의 교통강도를 대기행렬모델을 이용하여 찾아내고자 하였다. 이를 위해서 최적 교통강도 결정모델을 구축하고, 이를 검증하기 위하여 부산에 입지하고 있는 Off-Dock 컨테이너 터미널을 대상으로 컨테이너 차량 유출입 현황자료와 터미널 운영실태 자료를 수집하였다. 이를 기초로 대기비용과 운영비용이 서로 상쇄될 수 있는 최적의 교통강도를 정량적으로 찾아 낼 수 있었다. 또한, 구해진 교통강도를 통하여 현재 물류시설의 운영을 개선할 수 있는 방안을 도착시각 제어와 관련하여 그 효과에 대해 고찰하였다.

• 보건의료산업학회지
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• 제9권3호
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• pp.57-67
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• 2015

Objectives : This study has analyzed the relationship between DEA efficiency of costs-patient revenues, productivity per value added and management performance in mental hospitals. Methods : The relationship between DEA efficiency of costs-patient revenues, the productivity per value added and management performance were conducted with correlation analysis and logistic regression. Results : The DEA efficiency of costs-patient revenues had a significant causal relationship with the value added ratio to gross revenue indexing productivity per value added. On the other hand, it was revealed that the operating margin indexing management performance had a slightly significant causal relation with DEA efficiency of costs-patient revenues. Conclusions : The material costs should be focused on the management stability of mental hospitals, and known to the desirable management orientation for the higher efficiency of costs-patient revenues.

• 한국생산제조학회지
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• 제24권5호
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• pp.521-529
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• 2015

Owing to a reliance on imported products from Europe and Japan, the use of logistics equipment with poor energy efficiency coupled with high maintenance costs can lead to high operating costs for some domestic logistic centers. To lower their operating costs, the logistic centers use motorized roller conveyors. In order to commercialize this process, it is necessary to establish the test criteria and assess the reliability of the process. Currently, there exists no standard verification method to test the reliability of motorized roller conveyors. In this study, we propose reliability assessment criteria for a: i) reliability test, ii) environmental test, iii) safety test, and iv) lifetime test.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.636-642
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• 2009

The application of LCC-techniques is being introduced at the on-going procurement programs of various techniques. LCC-techniques have the common characteristic that all are designed to motivate contractors to design, manufacture and deliver equipment with lower life cycle costs. You may believe that savings may be in the acquisition cost component of life cycle costs. However, primary emphasis is generally on reducing and controlling operating and support costs by transferring more responsibility to the contractor for equipment operating and support cost performance. It has been found that life cycle cost procurement provisions must be individually tailored to each program. In this study, the currently identified LCC procurement techniques including a variety of LCC incentive provisions are introduced. Moreover, verification method, a procedural issue and incentive to application of LCC-techniques are examined.

• 산업경영시스템학회지
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• 제14권24호
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• pp.7-13
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• 1991

Recently, in FMS composing of various automatic equipments, the machines with lower operating costs, and with higher operating costs and replacement costs resulting from deterioration have been appearing successively as a result of rapidly advances in technology. "Control Limit Policy" [1] by using Markov decision policy, a kind of optimal economic replacement decision, well reflects and represents this environment. In this paper, it is reviewed that the decision method of the forecasted replacement alternatives in planning horizon under technological advances is derived. The proposed method is applied to a numerical example and some characteristics are examined by sensitivity. It is clarified that the method is relatively insensitive to changes of parameters at the present decision. decision.

• 수산해양기술연구
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• 제56권3호
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• pp.258-264
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• 2020

This study aimed to analyze the economic feasibility of the reduction of working safety accidents in stow net fishery through the prevention education to fishing crews. The benefit was evaluated by estimating insurance payment amount that was reduced through prevention education. The decreasing rate of working safety accidents was presumed to follow the experience in Japan. The cost was assumed as the cost of textbook development. Results indicated that IRR was estimated to be 79.9% in case of scenario assuming no additional operating costs while IRR was 56.3% in case of scenario assuming 10% additional operating costs. In addition, the economic feasibility would be secured when annual operating costs increased to 274 million won according to the result of sensitivity analysis.

• 한국환경과학회지
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• 제31권12호
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• pp.1061-1068
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• 2022

The purpose of this study was to develop a recycling system for ozone off-gas. Although the ozone transmission rate of the injector method differs slightly depending on the ozone injection rate, it reaches approximately 99%, which is very high. During the increase in water inflow to the ozone recycling system from 2 L/min to 10 L/min, the average ozone recycling rate was 99.4% at a 1 ppm ozone injection rate, 98.6% at a 2 ppm ozone injection rate, 98.1% at a 3 ppm ozone injection rate. Ozone treatment facility operating costs can be divided into the costs of pure oxygen production, ozone production, and maintenance. The annual operating costs of ozone treatment facilities in Korea are estimated to be approximately 38.9 billion won. The annual savings are estimated to be approximately 5.8 billion won when the ozone transfer rate of the diffuser method, which is mostly employed in domestic water treatment plants, is 85% and 15% of the ozone is recycled.

• Nuclear Engineering and Technology
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• 제38권6호
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• pp.561-574
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• 2006

This study presents the results of an economic analysis for a comparison of the single layer and double layer alternatives with respect to a HLW-repository. According to a cost analysis undertaken in the Korean case, the single layer option was the most economical alternative. The disposal unit cost was estimated to be 222 EUR/kgU. In order to estimate such a disposal cost, an estimation process was sought after the cost objects, cost drivers and economic indicators were taken into consideration. The disposal cost of spent fuel differs greatly from general product costs in the cost structure. Product costs consist of direct material costs and direct labor and manufacturing overhead costs, whereas the disposal cost is comprised of construction costs, operating costs and closure costs. In addition, the closure cost is required after a certain period of time elapses following the building of a repository.