• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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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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• v.7 no.8
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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.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.34
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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.

• Journal of Korean Academy of Nursing Administration
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• v.8 no.2
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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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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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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• v.8 no.10
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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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• v.12 no.1
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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.

• Journal of the Korean Operations Research and Management Science Society
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• v.6 no.1
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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.

• The Journal of Society for e-Business Studies
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• v.18 no.4
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• pp.169-193
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• 2013

This study investigates time series data on internet banking systems and business performances for 5 large-scale banks : Kookmin, Woori, Hana, City, Shinhan. These banks have the common features that they merged with other banks around 2000, hence they experienced massive IS integration between banks. This study adopted VAR and VECM for identifying Granger causality between the quality of internet banking systems and the performances of banks(operating revenue and cost). The main results are as follows. First, internet banking system impacts positively on the revenues as well as costs of banks. Second, the improvement of internet banking system is instigated by cost part more than revenue part. Hence, the results imply that banks tries to reduce operating costs via internet banking systems, however the systems rather increased the costs of banks, although the systems increased operating revenues of banks too.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.6D
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• pp.571-577
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• 2012

Recently, improving public transport service at disabled people has emerged as a social issue in rural areas. By improving expensive and inefficient existing operating system, the rural bus have to change a personalized service. Under these circumstances, government and local governments are promoting the introduction of DRT(Demand response transport). DRT system is intended to promote the user's convenience. But, until now, in-depth research on the operating costs for the introduction of DRT is not well known. This study aims to look at changes in number of vehicle and operating costs before and after introduction of DRT. The results are as follows. Even though introducing DRT, total number of vehicles increases because it does not reduce the existing number of vehicles. And this study estimated to about 5 to 12 percent of the increase in the operating cost comparing before introduction of DRT. Therefore, The introduction of DRT in rural areas is a need to set the exact purpose as promote transportation convenience or cost efficiency.