• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.220-223
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• 2003

This paper is aimed at determining the e-field distribution by apply voltage of air void, which can be generate air void in the XLPE cable for ultra high voltage. E-field distribution had an effect in XLPE due to the type and position of void, compared and studied. This method of analysis is based on the quasi-static electromagnetic 3D simulation program by boundary element method (BEM): Applied AC 3[kV], discretization of 2000 elements, 4 angular periodicity, The result of experiment indicate that E-field distribution appeared the highest levels on the void position of electrode 2[nm] outer boundary and shape of the smallest inner angle in the void. This will serve to explain the XLPE cable degradation studied of possible, connected cable variation of position and shape of void effects to e-field concentration.

• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.3
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• pp.63-70
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• 2018

In this study, a simple probabilistic approach using equivalent coefficient of consolidation ($c_e$) was proposed to consider the spatial variability of coefficient of vertical consolidation ($c_v$), and the effect of the probability distribution of coefficient of consolidation on degree of consolidation in heterogeneous soil was investigated. The statistical characteristics of consolidation coefficient were estimated from 1,226 field data, and four probability distributions (Normal, Log-normal, Gamma, and Weibull) were applied to consider the effect of probability distribution. The random fields of coefficient of consolidation were generated based on Karhunen-Loeve expansion. Then, the equivalent coefficient of consolidation was calculated from the random field and used as the input value of consolidation analysis. As a result, the probabilistic analysis can be performed effectively by separating random field and numerical analysis, and probabilistic analysis was performed using a Latin hypercube Monte Carlo simulation. The results showed that the statistical properties of $c_e$ were changed by the probability distribution and spatial variability of $c_v$, and the probability distribution of $c_v$ has considerable effects on the probabilistic results. There was a large difference of failure probability depend on the probability distribution when the autocorrelation distance was small (i.e., highly heterogeneous soil). Therefore, the selection of a suitable probability distribution of $c_v$ is very important for reliable probabilistic analysis of consolidation.

• The Journal of Industrial Distribution & Business
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• v.9 no.2
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• pp.65-72
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• 2018

Purpose - One of the biggest problems in the e-learning distribution process is the lack of quality content and learners' discredit in e-learning content. In order to respond to the various demands of the corporate education field appropriately, it is necessary to search for directions of new e-learning models that are out of traditional e-learning contents. The purpose of this study is to identify recent trend issues related to corporate e-learning and to suggest directions for development. Research design, data, and methodology - Based on the literature review, trend issues that should be considered important in corporate e-learning were derived. Online survey was conducted to evaluate the importance-feasibility of each issue to 13 experts on e-learning and corporate education. The contents of the questionnaire are as follows: 1) recognition of importance and feasibility of trend issues to be considered important in the future corporate education field; 2) factors to be considered in developing future e-learning contents. Results - Six trends derived from a comprehensive literature review. The most important e-learning trends for corporate education field were 'mobile learning', 'micro learning', 'blended learning', 'social learning', 'adaptive learning', 'engaged learning'. As a result of evaluating the importance and feasibility of each issue, experts point out that 'mobile learning' and 'micro learning' should be actively considered for introduction and utilization at present. In addition, 'social learning' and 'blended learning' need to be actively considered in the near future. On the other hand, experts recognized that 'adaptive learning' and 'engaged learning' need to be prepared from a long-term perspective. Conclusions - There are two main reasons for this result. First, in corporate e-learning, it is important to 1) be able to update on time, 2) the connection with the workplace is important. Second, it requires realistic verification of the expected performance of the learning model. To be considered part of the future are as follows: First, the value and effectiveness of the new e-learning type should be studied. Seconds, e-learning contents should be developed through adopting SAM or Agile methodology. Through this process, we would be able to enhance the quality in e-learning content.

• Journal of Magnetics
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• v.13 no.1
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• pp.34-36
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• 2008

For the measurement of the magnetic field distribution with high spatial resolution and high accuracy, the magnetic field sensing probe must be non-magnetic, but the MFM probe and sub-millimeter-meter size Hall probe use a ferromagnetic tip and block, respectively, to increase the sensitivity. To overcome this drawback, we developed a micro-size search coil magnetometer which consists of a single turn search coil, Terfenol-D actuator, scanning system, and control software. To reduce the noise generated by the stray ac magnetic field of the actuator driving coil, we employed an even function $\lambda$-H magnetostriction curve and lock-in technique. Using the developed magnetometer, we were able to measure the magnetic field distribution with a magnetic field resolution of 1 mT and spatial resolution of $0.1mm{\times}0.2mm$ at a coil vibration frequency of 1.8 kHz.

• Electrical & Electronic Materials
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• v.8 no.3
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• pp.332-339
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• 1995

In this paper, it was investigated the guided field intensity distribution of the channel in the silver & potassium ion-exchange glass-waveguide. The guided field intensity distribution analysis of ion-exchange glass-waveguide was based on the combination of the WKB dispersion relationship method with a Gaussian distribution function of refractive index profile and the Field Shadow method to the modeling of the channel waveguide. As the results of the channel waveguide modeling, it was represented 2-dimensional and 3-dimensional field distribution of ion-exchange glass waveguide.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.486-487
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• 2006

The authors have studied on the application of IEC 60364-4-44 to Korean electrical installations of buildings from 2004 sponsored by Korean ministry of commerce, industry and energy and the test field is established in K.E.R.I. (Korea Electrotechnology Research Institute). This paper presents the summary results of establishment of test field and analysis for the application of IEC 60364 in Korea. IEC 60364-4-44 provides rules for the protection against the effects of conducted and radiated disturbances on electrical installations. Especially this standard deals with the protection of low voltage facility against the ground fault in the high voltage side of power distribution system. Many countries define the regulations on the use and production of electrical facilities based on their own power system and technical references which are considered to be suitable for them. The background of circuit of IEC 60364-4-44 is based on the ungrounded system as most of European countries. However, since Korean electric power distribution system is based on multi-grounding system different from European system, it is necessary to evaluate or prove the effect of the IEC 60364-4-44 for introducing and applying it to the domestic grounding system as a Korean standard. This paper presents the establishment of test field to get background data to introduce the IEC 60364-4-44 and to evaluate the standard is applicable to domestic rule for the protection against ground fault through the related test

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.84-91
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• 2001

In in vitro cell experiments for the biological assessment of electromagnetic (EM) field, exposure system (ES) must be analyzed in terms of current density (J) and induced electric field intensity (E). Although in uniform B field, E and J in the sample medium are not distributed uniformly because of conductivity in sample dish. Thus, the precise estimation for E and J induced by uniform ELF within sample media is very important keys for successful in in vitro experiments. In this paper, we designed in vitro ELF ES with electromagnetic analysis using MATLAB simulator. Then we calculated from the measured B field to verify induced E & J distribution for random locations of cells within media in two cases of samples existence or not. ES with B field ranging from 0 to 20G consists of Helmholz coil and current generator based on the microprocessor. Also, we developed ELFES for each B field generation as uniform and non-uniform modes.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.172-178
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• 2019

Although the needs for providing resilient PNT information are increasing, threats due to the intentional RFI or space weather change are challenging to resolve. eLoran, which is a terrestrial navigation system that use a high-power signal is considered as a best back-up navigation system. Depending on the user's environment in the eLoran system, the user may use one of E-field or H-field antennas. H-field antenna, which has no restriction on setting stable ground and is relatively resistant to noise of general electronic equipment, is composed of two loops, and shows anisotropic gain pattern due to the different measurement at the two loops. Therefore, the H-field antenna's phase estimation value of signal varies depending on its direction even at the static environment. The error due to the direction of the signal should be eliminated if the user want to estimate the own position more precisely. In this paper, a method to compensate the error according to the geometric distribution between the H-field antenna and the transmitting station is proposed. A model was developed to compensate the directional error of H-field antenna based on the signal generated from the eLoran signal simulator. The model is then used to the survey measurement performed in the land area and verify its performance.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.312-314
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• 2000

The electric wave propagation characteristics of electromagnetic field by induction current shows a nonlinear distinction in the metal but linear on air. This paper is written about the magnetic transmission distinction in the metalic tube, which wrapped the center axis by the same direction. The electromagnetic field made by the transmission signal is transferred from the transmission coil area toward the receiving coil by the magnetic diffusion. So, it is different magnetic flux around the coil with one in the remote field area. Analyzing such a complex magnetic characteristic, we verified this theory by the vector analysis and presented eddy current mechanism and analytical model about magnetic distribution in the remote field area. This magnetic distribution rate in metal body will be very useful in the nondestructive inspection of the eddy current in remote field which is recently rising as a new technology.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1292-1295
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• 1987

In noninvasive temperature measurement within body, this paper is presented temperature measurement method in security and with effect from Applicator by electromagnetic, and it is analyzed heat generation quantity or temperature rise distribution by computer simulation within body. In this paper, two-dimensional model is considered and temperature distribution produced by RF capacitive heating system is analyzed by using Finit Element Method (F.E.M). A passibility of temperature distribution control is examined based on the position and size of Applicator.