• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.9
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• pp.2017-2036
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• 2012

Based on the current solutions to the problem of energy hole, this paper proposed a nonuniform node distribution clustering algorithm, NNDC. Firstly, we divide the network into rings, and then have an analysis and calculation on nodes' energy consumption in each ring of the network when clustering algorithm is applied to collect data. We also put forward a scheme of nonuniform node distribution on the basis of the proportion of nodes' energy consumption in each ring, and change nodes' active/hibernating states under density control mechanism when network coverage is guaranteed. Simulation shows NNDC algorithm can satisfyingly balance nodes' energy consumption and effectively avoid the problem of energy hole.

• Journal of the Korean Solar Energy Society
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• v.33 no.2
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• pp.18-27
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• 2013

This paper presents a method for assessing the wind energy potential at complex terrain using probability distribution. And the proper probability models of the parameters estimating the wind energy are presented. Finally a mixture-Weibull determined by numerical methods procedure are proposed to assess the probability distribution of the energy potential at a site. The developed method is applied to the Kwanjungchun Bridge and compared with wind records which the neighboring weather station.

• KIEAE Journal
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• v.12 no.3
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• pp.101-106
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• 2012

Lighting energy accounts for approximately 20% of the electrical energy used worldwide. Thus, High efficiency Light emitting diode(LED)lighting is getting more popular as the next generation lighting replaced to traditional lighting fixtures. Also, LED lighting not only has a long lifetime but also can realize a variety visual environments through the wavelengh control. The lighting energy varies depending on the Spectral Power Distribution(SPD) even though the Illuminance level is same. Therefore, This study indicates that the difference of indoor energy consumption under the same illuminance level when Spectral Power Distribution(SPD) is different. As a result, Lighting energy consumption under red-color emphasizing SPD is about 10% lower than under blue-color emphasizing SPDs.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1989.10a
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• pp.19-24
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• 1989

The electron energy distribution function in mercury discharge positive columns are calculated numerically from the Boltzmann eqation under a set of parameters, such as the electron temperature to. the atomic temperature Tw. the electron number density no. and the electric field E. Especially, using the approximation that collision cross sections only depend on the energy, the calculated electron energy distribution function was shown that it falls off rapidly in the high energy tail.

• Journal of the Korean Solar Energy Society
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• v.30 no.2
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• pp.54-64
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• 2010

Interest in new and renewable energies like solar energy and wind energy is increasing throughout the world due to the rapidly expanding energy consumption and environmental reasons. An essential requirement for wind force power generation is estimating the size of wind energy accurately. Wind energy is estimated usually using meteorological data or field measurement. This study attempted to estimate wind energy density using meteorological data on daily mean wind speed and the Weibull parameters in Seoul, a representative inland city where over 60% of 15 story or higher apartments in Korea are situated, and Busan, Incheon, Ulsan and Jeju that are major coastal cities in Korea. According to the results of analysis, the monthly mean probability density distribution based on the daily mean wind speed agreed well with the monthly mean probability density distribution based on the Weibull parameters. This finding suggests that the Weibull parameters, which is highly applicable and convenient, can be utilized to estimate the wind energy density distribution of each area. Another finding was that wind energy density was higher in coastal cities Busan and Incheon than in inland city Seoul.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.458-458
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• 2022

It is essential to reduce global carbon emissions, mainly from energy use. The water supply and distribution sector is a vital part of human society and is one of the primary energy consumers. The procurement and distribution of water require electricity to operate the pump to deliver water to users with sufficient pressure. As the water users are spatially distributed over a wide area, the energy required to deliver water to each user differs depending on the corresponding supplying element (reservoir, tank, pipe, pump, and valve). This difference in energy required for each user also comes with a difference in pressure availability which affects the level of service for individual users and the whole network. Typically, there is a disproportion where users close to the source experience excessively high pressure with low energy consumption. In contrast, remote users need more energy to get the minimum pressure. This study proposes the Energy Return Index (ERI) to quantify the pressure return from particular energy consumption to supply water to each node. The disproportionality can be quantified and identified in the network using the proposed ERI. The index can be applied to optimize the network elements such as pump operation and tank location/size to reach a balanced energy consumption with the appropriate level of service.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.59-67
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• 2006

Particles of soil are crushed when soil is compacted in the in-situ or lab. Among many factors that affect the crush of particles, compaction energy is a major factor. Because the crush of particles can change physical properties, the analysis of effect of compaction energy is very important. In this study, the fragmentation fractals were used for determining the change in grain size distribution and the effect due to change in grain size distribution was estimated. Compaction energy was increased by 50, 100, 200 and 300% based on the energy of standard A compaction test. As a result, grain size distribution curves were changed and fine particles increased as compaction energy were increased. Relative compaction were ranged between $93.38{\sim}107.67$. Fractal dimension of each site increased as compaction energy increased. Relative compaction is proportional to the fractal dimension but coefficients of permeability were in inverse proportional to the involution of fractal dimension.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2000.11a
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• pp.161-175
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• 2000

This study includes the fundamental planning of the sectoral management technology in energy distribution system so that the industry itself would be willing to participate for the effective energy conservation in its own sector. Furthermore guidlines for the effective energy management techniques have been presented by first analyzing the energy consumption structures, the energy loss problems, the energy conservation status and the technology demands, and second classifying, according to the energy distribution system, the energy source management, the energy generation & conversion facilities, the energy transportation ＆ storage facilities, the energy consumming facilities and the waste energy management, etc. in the industrial sector.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.4
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• pp.152-160
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• 2000

This paper presents an efficient evaluation method on the role of new energy storage systems, especially the secondary Battery Energy Storage (BES) systems, in the case where they are interconnected with the power distribution systems. It is important to perform the economic evaluation for the new energy storage systems in a synthetical and quantitative manner, because they are very costly in the early stage of their development and commercialization. In this paper, the multiple functions of BES systems, which are operated at distribution systems, such as load levelling, effective utilization of power distribution systems and uninterruptible power supply at the emergency conditions are classified and analyzed. And then the quantitative evaluation methods of the multiple functions for BES systems are proposed using the mathematical modelling.

• Solar Energy
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• v.10 no.2
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• pp.3-9
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• 1990

The recent technology of Wind Energy Conversion System(WECS) in the world is well-developed and the feasibility of WECS is better than the past time. So, it is necessary to re-analyze the characteristics of wind energy in this country. This paper deals with the analysis of wind energy distribution in Korean Peninsula, Cheju and Ullung island. The assessment was performed based on the raw data collected 64 meteorological stations for the last 10 years. The wind energy characteristics were analyzed hourly, monthly, seasonally and annually. The Weibull distribution was assumed and two parameters in all areas were calculated and the wind energy potential distribution in Korea was obtained.