• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.6
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• pp.497-505
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• 2016

Operating wind turbine generators at maximum power point requires maximum power point tracking (MPPT) control methods. However, conventional methods cannot track the appropriate maximum power point in situations involving wind turbine systems based on a series operation strategy. These systems comprise one or more local maximum power points, and conventional methods can detect only one local maximum power point closed by a current operation point. This study proposes an advanced MPPT method for the series operation strategy of a small, grid-connected wind turbine system. In determining the appropriate maximum point, operations at certain local maximum power points are analyzed. The results show one appropriate point, which is tracked by the proposed MPPT method. The effectiveness of the proposed method is verified by the experimental results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.43 no.5
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• pp.721-729
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• 1994

In this paper an optimization of the industrial congeneration system which have a thermal storage tank is proposed for the short-term operation strategy. Short-term operation costs of topping cycle and bottoming cycle are calculated by using the proosed model of a thermal storage tank. Simulation result of four cases are compared and analyzed each other.By these simulations which are similar to real operation circumstances. the validity of the proposed model is verified.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.24-26
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• 1994

This paper describes a numerical model for the short-term operation strategy of the cogeneration systems. Especially this paper considered various auxiliary equipments used for the effective operation of cogeneration system. Minimum daily operation costs of topping cycle are calculated by using LP. Simulation results of some cases are analyzed and compared each other. Through these simulations the validity of the proposed model considered various auxiliary equipments is verified.

• Strategy21
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• s.32
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• pp.5-35
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• 2013

The purpose of this thesis is to suggest how to plan ROK(Republic of Korea) Navy's strategy concerning to JOAC(Joint Operation Access Concept) and ASB(Air-Sea Battle) concept of US(United States) armed forces. Since 2006, US armed forces has been developing CONOPS(Concepts of Operations), JOAC & ASB. These concepts will not only affect security environment for Korea Peninsula and West Pacific Area, but also will be affected to ROK Navy's Strategy. Therefore, Korea Navy has to consider and review those concepts and should discuss the way to secure peace of Korea Peninsula. JOAC & ASB have been developed for securing operational access ability of US armed forces against enemy forces. A2/AD(Anti-Access, Area-Denial) is the strategy of possible enemy forces against US forces' approaching into the operation area and impede operations within area. US forces had to overcome enemy's A2/AD strategy in coming century to protect national interest and sustain global leadership. The main concept of JOAC & ASB is "Cross-domain Synergy", which means 'to eliminate duplicate and improve joint operability containing space and cyber operation area.' Korea Navy's acceptance of JOAC & ASB without any revising is not a rational choice. Without the amendment some problems can be occurred by the Korea navy's acceptance for the original version of JOAC & ASB. Those are "Missing differences of operation environment between Korea and US", "Impediment from neighbor nations, especially PRC (People's Republic of China)", and "Impediment inside from Korea armed forces". Therefore, Korea Navy has to evaluate and find out the way to solve for JOAC & ASB to apply for their strategy and minimise those possible problems above. This thesis is expected to be the solution.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1594-1598
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• 2007

Energy saving is an important topic for each heavy user of the power system, including railway operators. Therefore, four strategy of train operations studied that maximum speed reduction, reduced acceleration rate, anticipatory coasting, and saw-tooth coasting for energy saving. The Simulation model of the study used to investigate the performance of a railway system, and it was used to study the effect of energy saving strategies for the train operation. The Study investigate train operation strategy for energy saving, investigate the effect of strategy, and find the energy optimization of acceleration, coasting, braking section used Run-Curve simulator from train data.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.582-583
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• 2007

The distribution engineers experience some difficulty in getting to the voltage measuring sites because of severe traffic congestion and the long-distance feeders. Also, the 1,600,000 distribution transformers dispersed on the distribution feeder make it difficult to select the voltage measuring site properly and compute the voltage appropriateness ratio accurately. Accordingly in this paper, an on-line fuzzy operation and control strategy is designed based on the ubiquitous environments in order to improve the inefficiency of the existing off-line ULTC operation and control strategy. The simulation tool is designed in Visual C++ MFC language to show the effectiveness of the proposed strategy. And then it is proved by the simulation works.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.2
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• pp.97-105
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• 2008

This paper presents simulated and experimental test results of optimal control algorithm for an encapsulated ice thermal storage system with full capacity chiller operation. The algorithm finds an optimal combination of a chiller and/or a storage tank operation for the minimum total operation cost through a cycle of charging and discharging. Dynamic programming is used to find the optimal control schedule. The conventional control strategy of chiller-priority is the baseline case for comparing with the optimal control strategy through simulation and experimental test. Simulation shows that operating cost for the optimal control with chiller on-off operation is not so different from that with chiller part load capacity control. As a result from the experimental test, the optimal control operation according to the simulated operation schedule showed about 14 % of cost saving compared with the chiller-priority control.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.1089-1095
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• 2014

Innumerable microgrids would be operated independently by individual operators in a future smart grid. This kind of decentralized power system requires entirely different operation scheme in the actual power system and electricity market operation. Especially, frequency regulation is very important for successive energy trade in this multi-microgrid circumstance. This paper presents an optimal energy and reserve market participation strategy and operation strategy of energy storage system (ESS) by a microgrid operator (MGO). For definite evaluation of the proposed strategy, we postulate that the MGO should participate in the Power Exchange for Frequency Control (PXFC) market, which was devised by Maria Ilic and her coworkers and is suitable to the decentralized operation circumstances. In particular, optimal reserve capacity of the frequency control market and optimal market participation ratio of ESS between frequency control market and energy market are derived theoretically and evaluated by simulations utilizing Nordic Pool Elspot price data.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.839-849
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• 2023

The development of automation technology to reduce human error by minimizing human intervention is accelerating with artificial intelligence and big data processing technology, even in the nuclear field. Among nuclear power plant operation modes, the startup and shutdown operations are still performed manually and thus have the potential for human error. As part of the development of an autonomous operation system for startup operation, this paper proposes an action coordinating strategy to obtain the optimal actions. The lower level of the system consists of operating blocks that are created by analyzing the operation tasks to achieve local goals through soft actor-critic algorithms. However, when multiple agents try to perform conflicting actions, a method is needed to coordinate them, and for this, an action coordination strategy was developed in this work as the upper level of the system. Three quantification methods were compared and evaluated based on the future plant state predicted by plant parameter prediction models using long short-term memory networks. Results confirmed that the optimal action to satisfy the limiting conditions for operation can be selected by coordinating the action sets. It is expected that this methodology can be generalized through future research.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1999.10a
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• pp.123-130
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• 1999

The bus as a feeder trip should supply equality service to the whole community. But in spite of the change of latent demand to the bus by the variety of regional structural change, the existing bus route can not supply effective feeder service. For cope with the latent demand to the bus, this study establish a concept that frame of the bus operation and management. This study tackled to evidence this fact by analyzing the bus transport problems in terms of the urban growth, and following issues were discussed: 1) the strategy for improvement of bus operation, 2) the land use control which is appropriate for the public transport network, 3) the economical range to justify the bus operation, 4) the allowance for the private transport mode. On the second part of this study, the difference on the bus operation was compared to determine the range within which the bus operation can be justified. This would provide the direction to improve the management for bus operation and fundamental information to develop the bus operation system.