• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.8
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• pp.3821-3841
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• 2019

Cloud radio access networks (C-RANs) have been regarded in recent times as a promising concept in future 5G technologies where all DSP processors are moved into a central base band unit (BBU) pool in the cloud, and distributed remote radio heads (RRHs) compress and forward received radio signals from mobile users to the BBUs through radio links. In such dynamic environment, automatic decision-making approaches, such as artificial intelligence based deep reinforcement learning (DRL), become imperative in designing new solutions. In this paper, we propose a generic framework of autonomous cell activation and customized physical resource allocation schemes for energy consumption and QoS optimization in wireless networks. We formulate the problem as fractional power control with bandwidth adaptation and full power control and bandwidth allocation models and set up a Q-learning model to satisfy the QoS requirements of users and to achieve low energy consumption with the minimum number of active RRHs under varying traffic demand and network densities. Extensive simulations are conducted to show the effectiveness of our proposed solution compared to existing schemes.

• Journal of Multimedia Information System
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• v.3 no.4
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• pp.161-168
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• 2016

In this paper, a power flow simulator, which visualizes power flow and system configuration, is proposed and implemented. Generally, it is necessary to prepare a text file with power-system descriptions, which is one of the barriers for power-flow simulations. The proposed simulator has a function of automatic generations of IEEE common data format files from user-drawn power-system diagrams. Therefore, it is possible for users to carry out simulations only by drawing power system on display. In addition, the proposed simulator also has a function that power-system diagram is illustrated automatically from an IEEE common data format file. By using this function, it is possible to visualize amounts and directions of power flows on the bus-system diagram, which helps users to comprehend network dynamics intuitively. Because the proposed simulator allows including renewable-resource generators in power systems, it is useful to evaluate the power distribution system. It is shown in this paper that the proposed simulator can make IEEE common data format files correctly and illustrate intuitive power flow.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.17 no.4
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• pp.17-27
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• 2014

Wind power which is one of renewable energies is higher economical efficiency and technical maturity than other renewable energies. Recently, the government of ROK announced to increase the proportion of renewable energy through the National Energy Plan. Also, industry required to deregulate for large-scale wind power as Renewable Portfolio Standard (RPS) is introduced. Wind power whereas the eco-friendly energy, is a serious level of damage of the natural environment and topography when the wind power is located. Therefore, the study selected the indicators required for site selection of wind power and proposed the feasible area for wind power based on wind resource map. We selected the 15 indicators including 12 legal protected area, Ecology and Nature Map, rarity, and connectivity (National Ecological Network). After site selection, we should be considered slope and altitude at the stage of design for wind farm to mitigate the environmental impact. Results of analysis showed that 22.3% of wind resource map is available to locate wind power in real. Through the field survey we had verified the accuracy of the results was significantly correct.

• Environmental and Resource Economics Review
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• v.24 no.4
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• pp.629-655
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• 2015

Nuclear power generation is a major power source which accounts for more than 30% of domestic electricity generation. Electricity market needs to secure stability of base load. This study aimed at analyzing relationships between nuclear power generation and wholesale electricity price (SMP: System Marginal Price) in Korea. For this we conducted ARDL(Autoregressive Distributed Lag) approach and Granger causality test. We found that in terms of total effects nuclear power supply had a positive relationship with SMP while nuclear capacity had a negative relationship with SMP. There is a unidirectional Granger causality from nuclear power supply to SMP while the reverse was not. Nuclear power is closely related to SMP and provides useful information for decision making.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.547-554
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• 2018

Wind energy is widely recognized as one of the cheapest forms of clean and renewable energy. In fact, in several countries, wind energy has achieved cost parity with fossil fuel-based sources of electricity generation for new electricity generation plants. Offshore wind energy development promises to be a significant domestic renewable energy source for the target of korea government 3020 plan. A pivotal activity during the development phase of a wind project is wind resource assessment. Several approaches can be categorized as three basic scales or stages of wind resource assessment: preliminary area identification, area wind resource evaluation, and micrositing. This study is to estimate the wind power capacity of chonnam province offshore area using three basic stages based on the six meteorological mast data. WindPRO was used, one of a well-known wind energy prediction programs and based on more than 25 years of experiences in development of software tools for wind energy project development. The design results of offshore wind power generation capacity is calculated as total 2.52GW with six wind farms in chonnam offshore area.

• Journal of the Ergonomics Society of Korea
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• v.28 no.1
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• pp.37-51
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• 2009

The nuclear power industry in the world has recognized the importance of integrating non-technical and team skills training with the technical training given to its control room operators to reduce human errors since the Three Mile Island and Chernobyl accidents. The Nuclear power plant (NPP) industry in Korea has been also making efforts to reduce the human errors which largely have contributed to 120 nuclear reactor trips from the year 2001 to 2006. The Crew Resource Management (CRM) training was one of the efforts to reduce the human errors in the nuclear power industry. The CRM was developed as a response to new insights into the causes of aircraft accidents which followed from the introduction of flight recorders and cockpit voice recorders into modern jet aircraft. The CRM first became widely used in the commercial airline industry, but military aviation, shipboard crews, medical and surgical teams, offshore oil crews, and other high-consequence, high-risk, time-critical industry teams soon followed. This study aims to develop a CRM training program that helps to improve plant performance by reducing the number of reactor trips caused by the operators' errors in Korean NPP. The program is; firstly, based on the work we conducted to develop a human factors training from the applications to the Nuclear Power Plant; secondly, based on a number of guidelines from the current practicable literature; thirdly, focused on team skills, such as leadership, situational awareness, teamwork, and communication, which have been widely known to be critical for improving the operational performance and reducing human errors in Korean NPPs; lastly, similar to the event-based training approach that many researchers have applied in other domains: aircraft, medical operations, railroads, and offshore oilrigs. We conducted an experiment to test effectiveness of the CRM training program in a condition of simulated control room also. We found that the program made the operators' attitudes and behaviors be improved positively from the experimental results. The more implications of the finding were discussed further in detail.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.745-756
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• 2003

An analysis of wind environments using computational fluid dynamics and an evaluation of wind resources using measurement data obtained from meteorological observation sites at Homi-Cape, Pohang have been carrid out for siting a wind farm. It was shown that a numerical simulation using computational fluid dynamics would provide reliable wind resource map in complex terrain with land-sea breeze condition. As a result of this investigation, Homi-Cape wind farm with 11.25 ㎿ capacity has been designed for maximum power generation and 25.7 GWh electricity production is predicted.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1131-1132
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• 2011

For the purpose to flow control of pump in booster pump station, nonlinear-load inverter equipment is being introduced. While inverter equipment has the advantage of power-ratio savings and volume control, due to the vibration of pump and motor, secondary breakdown may occur Purpose in this paper is reliable facility operation by providing optimal operationg standards through vibration analysis of apply to drive pump with inverter in long-term in booster pump station.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1581-1586
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• 2010

Korea Power Exchange has successfully performed the Long-term Electricity Demand Forecasting. Recently there is a lot of change in electricity industry sector; the national master-plan for green gas emission reducing, rise of smart-grid, and new trend of electricity consumption, and it is becoming painful challenging for demand forecasting. In new circumstance the demand forecasting is required more flexible and more accurate.

• Environmental and Resource Economics Review
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• v.9 no.1
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• pp.1-23
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• 1999

배출권거래제도의 비용절감효과를 분석함에 있어 요소간 대체가능성 등 외부환경 변화에 대한 기업의 적응도를 반영하지 않은 공학적 추정치는 그 신뢰성에 한계가 있다. 또한 경제학적 분석방식을 시도한 연구의 대부분이 외부거래만을 대상으로 해온 반면에 거래실적의 다수를 차지하고 있는 내부거래에 대한 연구는 미미한 실정이다. 본 연구에서는 Gollop and Roberts (1985)의 경제학적 추정모형을 이용하여 미국 석탄발전소를 대상으로 $SO_2$ 배출권에 대한 내부거래의 비용절감정도를 측정한 후 효과의 크기 변에서 외부거래와의 차이를 규명하고자 한다.