• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.43.2-43.2
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• 2011

Wind turbine pitch/yaw bearings are relatively big and have different operating conditions like very heavy load to support compared with widely used industrial bearings. Once pitch/yaw bearings failed, according to their special surroundings, serious damages like higher repair costs and additional costs by stopped electricity generation are occur. Therefore, pitch/yaw bearings must be designed to have enough strength and fatigue life under actual operating conditions. In this study, with finite element analysis, it was investigated that stress distribution between rolling elements and raceway and comparatively analyzed using widely used guideline (NREL DG03). Design parameters of wind turbine pitch/yaw bearings are also analyzed, and it could be used as reference for the large bearing design field.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권8호
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• pp.1825-1842
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• 2013

Rapid growth of the IT industry has led to significant energy consumption in the last decade. Data centers swallow an enormous amount of electrical energy and have high operating costs and carbon dioxide excretions. In response to this, the dynamic consolidation of virtual machines (VMs) allows for efficient resource management and reduces power consumption through the live migration of VMs in the hosts. Moreover, each client typically has a service level agreement (SLA), this leads to stipulations in dealing with energy-performance trade-offs, as aggressive consolidation may lead to performance degradation beyond the negotiation. In this paper we propose a heuristic based resource allocation of VM selection and a VM allocation approach that aims to minimize the total energy consumption and operating costs while meeting the client-level SLA. Our experiment results demonstrate significant enhancements in cloud providers' profit and energy savings while improving the SLA at a certain level.

• 산업경영시스템학회지
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• 제18권34호
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• pp.193-204
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• 1995

Many studies show that the value of the warehouse is good. However, studies explicitly mention the tradeoff between costs of operating the warehouse and benefits from the warehouse. Also, it is important to know when the benefits overcome the costs. We study a one-warehouse/N-retailer(s,Q) distribution system with stochastic lead times in order to answer two questions: "What are the optimal policies of the system that minimizes total system costs\ulcorner" and given the optimal policies, "Is the value of the warehouse always good\ulcorner" We use an analytical model for answering the questions. We find that the optimal policies are different from those with deterministic lead times. In fact it is reverse. We alse find the existence of the breakeven point beyond which the benefits starts overcomming the costs. And, we show that one of the breakeven points is the mean ratio of a supplier's lead time to transportation lead time between the warehouse and the retailer. Finally, we show that the breakeven point is sensitive to the ratio of holding costs of the warehouse and the retailer and it is also sensitive to the unit backorder costs at the retailer.sts at the retailer.

• 간호행정학회지
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• 제8권2호
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• pp.283-293
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• 2002

Purpose: The purpose of this study was to define cost-countable perioperative nursing activities and to analyze the cost of each nursing activities based on the Resource-Based Relative Value Scale (RBRVS). Method: Researcher and 3 research assistants observed and documented the 83 operating patients in order to measure nursing time for each of the perioperative nursing activities. And then, 35 operating room nurses with at least one year of perioperative nursing experience were observed for the RBRVS of perioperative nursing activities. Finally, the direct and indirect nursing costs were estimated. Result: Nursing costs of 25 nursing activities were estimated using the RBRVS. Most expensive nursing activities were delivery of the instrument and implement for OP team (9,780 won per hour) and behavior of wash, pack, disinfect the instrument (6,770). Conclusion: Based on the relative values of each perioperative nursing activities estimated in this study, proper medical reimbursement system should be established in a near future.

• 전기학회논문지
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• 제65권6호
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• pp.969-978
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• 2016

Around the world are increasing the demand for ESS. Currently, the domestic is expected to benefit by operating ESS. In the domestic, it is expected to benefit from operations of the installed ESS because of the introduction of ESS less capacity. However ESS capacity to the maximum profit occurs is unknown. ESS is different from the charge-discharge characteristics and the reserve to replace, depending on the application. Therefore, it should be established in accordance with the ESS optimal capacity according to the purpose used because it can maximize the quality and efficiency of the electric energy. To the ESS optimal capacity estimation by the purpose used, It should compare the investment cost caused by ESS facility installation and operation cost caused by operating ESS. In this paper, the operation mathematical model for estimating marginal operation costs established. In operation mathematical model, operating cost is considered fuel cost and no-load cost start-up cost. Because no-load cost and start-up cost are not related to cost and power plant output, there are expressed an integer variable costs as a step function.

• The Journal of Asian Finance, Economics and Business
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• 제8권10호
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• pp.87-95
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• 2021

This study aims to demonstrate the impact of BPR in reducing cost in international business organizations by analyzing the impact of decentralization, re-engineering organizational structures, re-engineering human resources, industrial process technology, improving total quality standards, and value engineering. The study population includes all the international business organizations operating in the Middle East, with the condition that they operate in at least four countries. The results showed that there is a significant effect of all dimensions of BPR in reducing costs in international business organizations operating in the Middle East. When studying the impact of the dimensions combined, the moral effect appeared at each processes (decentralization, re-engineering of human resources and industrial process technology), while the moral effect did not appear in (rebuilding organizational structures, improving total quality standards, and value engineering). This does not negate the importance of the impact of these dimensions, but rather shows a disparity between dimensions in reducing cost, when studying its combined effect. The study recommends that organizations should adopt modern management accounting methods, including value engineering, in order to identify and enhance activities that add value to the organization's operations, as well as identify and eliminate non-value adding activities, in order to reduce costs.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.11-19
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• 2020

In recent years, oil prices have continued to be low owing to the development of unconventional resources such as shale gas, coalbed methane gas, and tight gas. However, shipping companies are still experiencing difficulties because of recession in the shipping market. Hence, they devote considerable effort toward reducing operating costs. One of the important parameters for reducing operating costs is the frictional resistance of vessels. Generally, a vessel is covered with paint for smoothing its surface. However, frictional resistance increases with time owing to surface roughness, such as that caused by fouling. To prevent this, shipping companies periodically clean or repaint the surfaces of vessels using analyzed operating data. In addition, studies using various methods have been continuously carried out to identify this phenomenon such as fouling for managing ships more efficiently. In this study, numerical simulation was used to analyze the change in the resistance performance of a ship owing to an increase in surface roughness using commercial software, i.e., Star-CCM+, which solves the continuity and Navier eStokes equations for incompressible and viscous flow. The conditions for numerical simulation were verified through comparison with experiments, and these conditions were applied to three ships to evaluate resistance performance according to surface roughness.

• 한국경영과학회지
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• 제6권1호
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• pp.25-32
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• 1981

The optimum design problem of a proposed oil pipeline network has been formulated as a zero-one programming model to determine the optimum sizes of pipe and pump which minimize the sum of material costs and operating costs during the 20 years of life span. Applying to a real situation, the problem constitutes an assignment type zero-one programming with 372 zero-one variables and 13 constraints. A heuristic algorithm has been developed based on the modified Petersen algorithm utilizing the special form of the activity matrix. The results showed impressive cost savings of 37 percent of the total cost from the original proposal.

• 한국전자거래학회지
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• 제18권4호
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• pp.169-193
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• 2013

본 논문에서는 시중 5대 은행(국민, 우리, 하나, 씨티, 신한)을 대상으로 인터넷 뱅킹 시스템의 영업성과의 내생성에 대해 시계열분석을 하였다. 상기 다섯 개 은행의 공통점은 2000년을 전 후로 타 은행과 합병한 은행들이라는 것이다. 합병의 과정을 통해 정보시스템 통합을 위한 대형 IT 프로젝트를 경험한 은행들로 합병 이후 전반적으로 인터넷 뱅킹 시스템의 향상을 보인 은행들이다. 본 연구는 VAR와 VECM 모델을 기반으로 인터넷 뱅킹 시스템의 품질과 은행의 성과 간(영업수익과 비용)의 그랜져 인과관계를 분석하였다. 논문의 주요 결과는 다음과 같다. 첫째, 인터넷 뱅킹 시스템은 은행의 영업수익과 비용에 긍정적인 영향을 미쳤다. 둘째, 인터넷 뱅킹 시스템은 수익요인보다는 비용요인에 의한 성과향상이 유발되었다. 이는 은행들이 운영비용 감축을 목적으로 인터넷 뱅킹에 투자했을 가능성을 시사한다.

• 대한토목학회논문집
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• 제32권6D호
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• pp.571-577
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• 2012

최근 농어촌지역의 교통약자에 대한 대중교통서비스 개선 등이 사회적 관심을 받고 있고, 기존 고비용 저효율인 버스운영 시스템의 개선을 통하여 이용자 맞춤형서비스로의 전환 필요성이 제기되고 있다. 이러한 상황에서 정부 및 지자체에서는 기존 농어촌버스의 노선운행시스템 대안으로 수요대응형교통(Demad Responsive Transport) 도입을 추진하고 있다. DRT는 교통소외지역의 이용자편의를 증진시키는 것을 큰 목적으로 하고 있으나, 지금까지 도입에 따른 비용분석에 관한 연구가 거의 없는 실정이다. 본 연구는 농어촌지역에 DRT를 도입하였을 경우 차량운행대수 및 운행비용의 변화를 살펴봄으로써 비용측면에서의 도입가능성을 살펴보았다. 분석결과 농어촌버스의 대당 운행노선수의 과다와 노선혼재의 특성으로 DRT가 도입되더라도 기존 차량대수의 감축효과가 미미하기 때문에, 기존 노선운행시스템에 비해 추가차량 소요가 발생하였다. 그리고 이러한 추가차량 소요는 운행비용 증가를 가져오게 되어, 도입 전과 비교하여 약 5~12%의 운행비용 증가가 발생할 것으로 추정되었다. 따라서 향후 농어촌지역에 DRT 도입을 위해서는 교통소외 지역주민의 교통편의증진을 목적으로 할 것인지, 기존 노선운행시스템의 비용비효율 해소를 목적으로 할 것인지에 대한 면밀한 검토와 방향설정이 필요하다는 것을 제시하였다.