• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.418-421
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• 2009

Renewable energy or green energy is a hot issue in theses days. Since wind resource can be endlessly supplied by nature, researchers and common people are interested in study how to use that resource at home or company. Especially, many architects have tried to integrate wind power generator for a part of building. So in this paper, three buildings installed wind power turbine are targed to CFD analysis and these buildings are Bahrain trade center, Discovery tower, and Pearl river tower. Bahrain trade center is the first builidng installed real wind turbine, Discovery tower is constructing at Texas, and Pearl river tower is designed and proved by china researchers. These buildings have very different type of wind power turbine and each turbine has different conditions for best power generation. Therefor this paper will focus on characteristic shape of buildings, wind power turbine type, and expected purpose of construction. Moreover, CFD analysis will show wind flow pattern and wind speed while wind is passing through wind turbine of three tall buildings. CFD analysis for three buildings make comparison the wind flow patterns with experimental result.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.611-627
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• 2017

For enhancing the coverage of wireless networks and increasing the spectrum efficiency, small cell networks (SCNs) are considered to be one of the most prospective schemes. Most of the existing literature on resource allocation among non-cooperative small cell base stations (SBSs) has widely drawn close attention and there are only a small number of the cooperative ideas in SCNs. Based on the motivation, we further investigate the cooperative approach, which is formulated as a coalition formation game with power control algorithm (CFG-PC). First, we formulate the downlink sub-channel resource allocation problem in an SCN as a coalition formation game. Pareto order and utilitarian order are applied to form coalitions respectively. Second, to achieve more availability and efficiency power assignment, we expand and solve the power control using particle swarm optimization (PSO). Finally, with our proposed algorithm, each SBS can cooperatively work and eventually converge to a stable SBS partition. As far as the transmit rate of per SBS and the system rate are concerned respectively, simulation results indicate that our proposed CFG-PC has a significant advantage, relative to a classical coalition formation algorithm and the non-cooperative case.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.3
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• pp.93-100
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• 2004

Test scheduling of SoC (System-on-a-chip) is very important because it is one of the prime methods to minimize the testing time under limited power consumption of SoC. In this paper, a heuristic algorithm, in which test resources are selected for groups and arranged based on the size of product of power dissipation and test time together with total power consumption in core-based SoC is proposed. We select test resource groups which has maximum power consumption but does not exceed the constrained power consumption and make the testing time slot of resources in the test resource group to be aligned at the initial position in test space to minimize the idling test time of test resources. The efficiency of proposed algorithm is confirmed by experiment using ITC02 benchmarks.

• Journal of the Korean Solar Energy Society
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• v.38 no.4
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• pp.43-54
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• 2018

In this study, we assessed dependency of small hydropower potentials on the two different runoff such as the estimated runoff based on the rainfall amounts and measured runoff. The hydpropower potentials were evaluated using actural power generations taken from Deoksong, Hanseok, and Socheon small hydropower plants over Han and Nakdong river basins, respectively. As a result of comparing the actual power generation amount with the potential amount based on the rainfall amount and the estimated amount based on the observed flow amount by each small hydroelectric power plant, the degree of latent small hydro energy by the observed flow was confirmed to be high. It is confirmed that the potential hydroelectric power generation rate is estimated to be about average 30%Point higher than the actual generation amount as a result of the measured flow rate rather than using the rainfall amount. Based on this, a method for improving the degree of the actual generation amount is proposed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.187-190
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• 2005

As the interest in environmental pollution increases acknowledging that interrelated energy and environment problem, the use of renewable energy is uprising. Among the renewable energy resource, Wind and Solar energy has no environmental impact and use unlimited resource. Solar power is not available during the night time, the wind power can be used as a natural supplement Data of irradiance and wind speed recorded in average day for years are used. These data are used to obtain the probability average power of wind and solar systems. In this paper, A technique that can lay the foundation fot building the wind and solar power systems of a southwest area in a optimal way.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.625-629
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• 2015

The second-generation HTS wire its YBCO coated conductor is widely used in the superconducting power apparatus. The YBCO coated conductor uses the normal-superconducting junction to increase the transport capacity of superconducting power apparatus when it is applied. The normal-superconducting junction can be a cause of reducing the stability of the superconducting power apparatus when a fault current is applied. Thus, in this study we have conducted the effect analysing normal-superconducting junction for the fault current using transport current and quench resistance. From the experimental results when a fault current is applied, the effect on the normal-superconducting junction is reduced the larger the amplitude of the fault current and is helpful to maintain the thermal stability of the HTS wire.

• Environmental and Resource Economics Review
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• v.11 no.2
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• pp.233-260
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• 2002

This paper tries to analyze the efficiency structure and regulatory effects in electric power industry by using total factor productivity and indices based on cost function method. This paper performed an empirical analysis on the efficiency improvement and optimal scale taking the cost aspect in electricity industry into account. By expanding the cost structure framework, this paper proposes the analytical method regarding the needs of technology regulation and presents the empirical results which can be verified. Hence, this work can play a key role in decision-making of the national power development and regulatory policy. The empirical result indicates that the electricity industry in Korea has been in the state of economies of scale until 1980s, However, due to sustained growth of power generation, economies of scale declined and subsided after 1980s and then diseconomies of scale is shown recent years. The analysis on the effect of technology regulation shows the national large-scale base-load power plant development-oriented policy until so far contributed substantial cost effect to the electricity industry. The empirical result indicates that the reserve requirement as one of means of technology regulation policy did not contribute to the economies of scale but positive effect on the total factor productivity in Korea.

• Journal of the Korea Society of Computer and Information
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• v.11 no.3
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• pp.161-166
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• 2006

In this paper, CPLD low power technology mapping using reuse module selection under the time constraint is proposed. Traditional high-level synthesis do not allow reuse of complex, realistic datapath component during the task of scheduling. On the other hand, the proposed algorithm is able to approach a productivity of the design the low power to reuse which given a library of user-defined datapath component and to share of resource sharing on the switching activity in a shared resource Also, we are obtainable the optimal the scheduling result in experimental results of our using chaining and multi-cycling in the scheduling techniques. Low power circuit make using CPLD technology mapping algorithm for selection reuse module by scheduling.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.7
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• pp.2047-2066
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• 2024

In order to improve the coverage and achieve massive spectrum access, non-orthogonal multiple access (NOMA) technology is applied in millimeter wave massive multiple-input multiple-output (mMIMO) communication network. However, the power assumption of active sensors greatly limits its wide applications. Recently, Intelligent Reconfigurable Surface (IRS) technology has received wide attention due to its ability to reduce power consumption and achieve passive transmission. In this paper, spectral efficiency maximum problem in the millimeter wave mMIMO-NOMA system with IRS is considered. The sparse RF chain antenna structure is designed at the base station based on continuous phase modulation. Furthermore, a joint optimization problem for power allocation, power splitting, analog precoding and IRS reconfigurable matrices are constructed, which aim to achieve the maximum spectral efficiency of the system under the constraints of user's quality of service, minimum energy harvesting and total transmit power. A three-stage iterative algorithm is proposed to solve the above mentioned non-convex optimization problems. We obtain the local optimal solution by fixing some optimization parameters firstly, then introduce the relaxation variables to realize the global optimal solution. Simulation results show that the spectral efficiency of the proposed scheme is superior compared to the conventional system with phase shifter modulation. It is also demonstrated that IRS can effectively assist mmWave communication and improve the system spectral efficiency.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.6
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• pp.163-171
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• 2021

In this paper, the energy transaction system was optimized by applying a resource allocation algorithm and deep reinforcement learning in the distributed power system. The power demand and supply environment were predicted by deep reinforcement learning. We propose a system that pursues common interests in power trading and increases the efficiency of long-term power transactions in the paradigm shift from conventional centralized to distributed power systems in the power trading system. For a realistic energy simulation model and environment, we construct the energy market by learning weather and monthly patterns adding Gaussian noise. In simulation results, we confirm that the proposed power trading systems are cooperative with each other, seek common interests, and increase profits in the prolonged energy transaction.