• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.85-89
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• 2010

During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multi-grounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A effect by grounding resistance of poles of ground fault current in the 22.9[kV] multi-ground distribution system. by field tests.

• Journal of the Korean Institute of Navigation
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• v.10 no.1
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• pp.51-79
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• 1986

From time to time the light weight distribution has been discussed, It play an important part in the preliminary design state because of its influence on the available deadweight. Up to the past, the Light weight distribution acting on the ship has been estimated graphically by means of integraph or approximately by the simplified calculations. Recent development has made it possible to use Lloyd's coffin method or Robb's coffin method for Bulk Carrier, Tanker, Cargo ship where the hull weight is distributed based upon the $C_B$ The hull weight distribution is then super-composed by number of fixed weights(i.e. machinery , equipment, etc.) The authors built up the method by which the Light weight distribution is calculated using a computer. In the usual calculations, the higher accuracy is aimed at, the longer time would be taken, therefore the accuracy would not be so good as to be expected if the time is restricted. The method using a computer can dissolve these and calculated accurately in shorter time the Light weight distribution with less data.

• Journal of Electrical Engineering and Technology
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• v.7 no.2
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• pp.225-229
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• 2012

This paper proposes a reduced-scale simulator that can replace numerical analytic methods for the estimation of potential distribution caused by ground faults in various grounding systems. The simulator consists of a hemispherical electrolytic tank, a three-dimensional potential probe, a grounding electrode, and a data acquisition module. The potential distribution is measured using a potentiometer with a position-tracing function when a test current flows to the grounding electrode. Using the simulator, we could clearly analyze the potential distribution for a reduced- scale model by one-eightieth of the buried depth and length of the grounding rod and grounding grid. Once both the shape of the grounding electrode and the fault current are known, the actual potential distribution can be estimated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.1
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• pp.21-27
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• 2016

The study concerning about the grid connection of the large-capacity battery energy storage system(BESS) is increasing. However, the protection study which is necessary to maintain the reliability of distribution system has been hardly performed. Therefore, this paper analyzes the effect of reclosing among protection issues in distribution system with BESS and proposes the new relcosing method. To verify the proposed method, the BESS, distribution system, and proposed method are modeled by using EMTP/ATPDraw and the various simulations according to the fault clearing time are performed. The simulation results show that the reclosing in distribution system with BESS is successfully performed by proposed method and the operation of BESS is not affected from reclosing.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.47-53
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• 2015

The study concerning about the grid connection of the large-capacity energy storage system(ESS) is increasing. However, the transient study such as lightning or switching surge necessarily occurred at power system with ESS has been hardly performed. Therefore, this paper performs the analysis of lightning surge in distribution system with ESS using electromagnetic transient program(EMTP). The battery model in Matlab/Simulink is modeled by EMTP, which is the specialized software for power system transient study. Also, the bi-directional power electronics for interconnection of the battery and distribution system are modeled by EMTP. When the lightning is occurred at interconnection point of ESS, this paper simulates the existence of ESS and operation conditions of ESS and analyzes the surge in distribution system and ESS according to the various conditions.

• The Korean Journal of Applied Statistics
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• v.29 no.4
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• pp.571-579
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• 2016

Most of studies related to the distributions of quadratic forms are conducted under the assumption of multivariate normal distribution. In this paper, we suggested an approximation to the distribution of quadratic forms based on multivariate skew-normal distribution as alternatives for multivariate normal distribution. Saddlepoint approximations are considered and the accuracy of the approximations are verified through simulation studies.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.726-732
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• 2002

Pressure drop could happen in the water distribution systems due to pipe breaks or maintenance. The pressure drop causes the water service shutdown and nodal water demands should be reduced in some areas. The conventional analysis method of water distribution systems can not consider the change of nodal water demands caused by these pressure drops. This study is to investigate the variation of nodal water demands according to the nodal water pressure and its effect on the analysis of water distribution systems. For these purpose, one real water service district was selected as a study area. As a result, nodal water demand patterns according to the water pressure could be suggested. Also, we could confirm that the suggested new analysis method for the water distribution systems which considering water pressure drops could be more reliable than the conventional method.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.55-61
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• 2011

This study analyzed on the characteristics of temperature distribution in an active regeneration DPF using computer simulation. In order to verify the boundary condition of analysis, results of temperature distribution in DPF are compared between experimental and computer simulation. Using this boundary condition, temperature distribution and filter's durability in DPF analyzed according to various operating conditions. The results of computational analysis are agreed well with experimental ones from the tendency of temperature distribution of axis and radius direction. The temperature increases and the axial temperature gradients in DPF according to velocity of exhaust gas are lowered as the high velocity of exhaust gas. But the temperature gradients of radius direction at exit side in DPF are grown as the high velocity of exhaust gas. The results according to inlet temperature of exhaust gas show that the increase ratios of temperature in DPF are grown as the high temperature of exhaust gas.

• Journal of Information Technology Services
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• v.18 no.1
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• pp.131-140
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• 2019

This study compares and analyzes the spatial distribution of people in two cities using location information in twitter data. The target cities were selected as Paris, a traditional tourist city, and Dubai, a tourist city that has recently attracted attention. The data was collected over 123 days in 2016 and 125 days in 2018. We compared the spatial distribution of two cities according to the two periods and residence status. In this study, we have found a hot place using a spatial statistical model called dart-shaped space division and estimated the urban area by reflecting the distribution of tweet population. And we visualized it as a CDF (cumulative distribution function) curve so that the distance between all the tweets' occurrence points and the city center point can be compared for different cities.

• Journal for History of Mathematics
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• v.35 no.6
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• pp.149-170
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• 2022

This study discusses in terms of historical genesis whether it is reasonable for Bayes to introduce a prior uniform distribution. In this study, we try to analyze the way he dealt with postulates, lemmas, and propositions in Bayes' essay and to understand its characteristics. The results of the study show that Bayes used random variables for two parameters and that the two random variables were converted to each other through cumulative distribution. Furthermore, it is revealed that the introduction of prior uniform distribution can be justified by this way.