• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.470-472
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• 2003

This paper presents the measurement results and the statistical analysis of electrical and magnetic fields in the vicinity of overhead distribution lines. The maximum values of electrical and magnetic fields are 0.042kV/m and 8.3mG. The median values are 0.005kV/m and 1.3mG. The electrical and magnetic fields of distribution lines are compared to those of transmission lines and home appliances.

• ETRI Journal
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• v.33 no.6
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• pp.949-952
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• 2011

In this letter, a simplified suboptimum receiver based on soft-limiting for the detection of binary antipodal signals in non-Gaussian noise modeled as a generalized normal-Laplace (GNL) distribution combined with Gaussian noise is presented. The suboptimum receiver has low computational complexity. Furthermore, when the number of diversity branches is small, its performance is very close to that of the Neyman-Pearson optimum receiver based on the probability density function obtained by the Fourier inversion of the characteristic function of the GNL-plus-Gaussian distribution.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.1
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• pp.7-14
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• 2002

In power system study, relibility assessment has been an important topic during past several decards because sudden power interruption can bring about enormous economic loss. although the size of a substation is smaller than that of generation system or transmission system, switching actions after fault(s) make reliability assessment of substation rather complex situations such as switching actions easily and permit various probability distributions in describing substation elements. Despite this ability of Monte Carlo simulation, one-parameter exponential distribution is still popular in this reliability assessment. This paper examines the characteristics of several two-parameter probability distributions, and offers new parameter decision rule based on average and variance of the target to be modelled. In case study, this paper shows the profits by using Weibull distribution which is one of two-parameter probabilistic distributions instead of exponential one.

• Journal of information and communication convergence engineering
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• v.3 no.2
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• pp.90-92
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• 2005

As the result of the study shows, Round Robin Algorithm allows servers to ensure definite traffic distribution, unless incoming data loads differ much. Although error levels are high in some cases, they were eventually alleviated by repeated tests for a long period of time. The study uses two software packages (Packet Capture and Round Robin Test Package) to check packet volume from Virtual Network Structure (data generator, virtual server, Server 1, 2, 3), and finds out traffic distribution toward Server 1, 2, and 3. The functions of implemented Round Robin Load Balancing Monitoring System include round robin testing, system monitoring, and graphical indication of data transmission and packet volume.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.77-82
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• 2004

Being in an internet era, the rapid transmission of 3D mesh models is getting more important and efforts toward the compression of various aspects of mesh models have been provided. Even though a mesh model usually consists of coordinates of vertices and properties such as colors and normals, topology plays the most important part in the compression of other information in the models. Despite the extensive studies on Edgebreaker, the most frequently used and rigorously evaluated topology compressor, the probability distribution of its five op-codes, C, R, E, S, and L, has never been rigorously analyzed yet. In this paper, we present probability distribution of the op-codes which is useful for both the optimization of the compression performance and a priori estimation of compressed file size.

• Journal of Welding and Joining
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• v.24 no.6
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• pp.28-32
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• 2006

Laser Transmission Joining (LTJ), which is a joining process of polymers by using different transmission rates of materials, was studied numerically. Unlike previous studies, energy loss by reflection at the surface was included. Besides, energy absorbed in the transparent substrate is also considered to increase the accuracy of the analytical results. Furthermore, thermal deformations of the substrates were also calculated. Temperature distribution of the substrates on the joining process could be effectively predicted by using the thermal analysis model developed, which could also analyze the rising phenomenon of the absorbing substrate by bulge effect. Calculated results show that temperature of the absorbing substrate is higher than that of transparent substrate when the laser is being radiated, and this temperature difference causes more thermal deformation in absorbing substrate, which results in the surface rise of the absorbing substrate. Comparison of calculated results with corresponding experimental results could confirm the validity of the numerical analysis model proposed.

• Journal of Electrical Engineering and Technology
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• v.11 no.2
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• pp.436-444
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• 2016

Oil-paper insulation of valve-side windings in converter transformers withstand electrical stresses combining with AC, DC and strong harmonic components. This paper presents the physical mechanisms and experimental researches on partial discharge (PD) of oil-paper insulation at pulsating DC voltage. Theoretical analysis showed that the phase-resolved distributions of PDs generated from different insulated models varied as the increase of the applied voltages following a certain rule. Four artificial insulation defect models were designed to generate PD signals at pulsating DC voltages. Theoretical statements and experimental results show that the PD pulses first appear at the maximum value of the applied pulsating DC voltage, and the resolved PD phase distribution became wider as the applied voltage increased. The PD phase-resolved distributions generated from the different discharge models are also different in the phase-resolved distributions and development progress. It implies that the theoretical analysis is suitable for interpretation of PD at pulsating DC voltage.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.466-469
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• 2008

As the industry develops, they are interested in the fault of electric machines and the effect on human beings by electromagnetic fields and waves which generate through much use of electric machines and appliances. In foreign country, they confirmed the standard about electromagnetic interference and compatibility(EMI/EMC) of electromagnetic fields and waves generating electricity transmission/distribution equipments and electric appliance. In Korea, such criteria are applied too. Before EMI/EMC standard is applied, it is important to prepare the plan to predict and reduce electromagnetic fields and waves which generate in the inner and the outer part of electric machinery. To solve such a problem, they calculated Maxwell's equations by finite element method(FEM) and finite difference method(FDM) in most papers. However, these methods have the disadvantage that mathematical expansions are complex and need much memory allocations for grid and mesh generations. In this paper, we introduce transmission line matrix(TLM) method that media of which trains consists are regarded as transmission lines for electromagnetic field calculation in Korean High Speed Train, calculate the electric and magnetic field, and analyze the results.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.5
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• pp.491-500
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• 2016

Pressure monitoring is expected to be expanded in a water distribution system according to accelerated development of smart water network management technologies caused by appearances of affordable digital infrastructures like computing, storage and bandwidth. However, the placement of pressure sensors has been determined by engineer's technical decisions since there is no well-defined criteria for deciding a suitable location of pressure sensor. This study presents a placement method of pressure sensors based on the consideration of allowable error in calibrating water network analysis modeling. The proposed method is to find a minimum set of pressure sensors for achieving a reliable management of water transmissions main and increasing the efficiency of their real-time operation. In the case study in Y area's transmission main, the proposed method shows equally distributed pressure sensors in terms of hydraulics. It is expected that the proposed method can be used to manage transmission mains stably and construct a robust real-time network analysis system as a minimal criteria.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.5
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• pp.245-249
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• 2006

Corona characteristics of conductors are dependent on the electric field conditions in the immediate vicinity of the conductors. In case of DC transmission line, particularly, the space charge plays an important role in the electric field distribution. Therefore, DC corona cage simulation is necessary for long-term test in the same conditions. This paper presents the results of designing and constructing hardwares such as DC power supply, measurement system and DAS to carry out the simulation. The corona cage longitudinally is divided into five equal length sections and three inner sections of those are isolated from the ground of outer cage. The measurement items are radio noise, corona current, television noise, audible noise and meteorological conditions. In the next step, various simulations about the type and configuration of two or three candidate conductors will be conducted. And then finally an environmentally-friendly conductor for HVDC overhead transmission line will be decided.