• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.10 no.1
• /
• pp.109-121
• /
• 1999

In this paper, HF band LPDA(Log-periodic Dipole Antenna) and MLPDA(Modified Log-periodic Dipole Antenna) above lossy grounds were analyzed using moment method by considering the practical media parameter of lossy grounds, not assuming free space or perfect ground approximation. The radiation pattern and gain of LPDA and MLPDA as functions of frequency, antenna height from ground, and antenna tilt angle are presented, and the lossy ground effect on antennas characteristics are described. MLPDA was found to exhibit a smaller variation for gain and radiation pattern and a higher maximum beam direction relative to LPDA. It was shown that media parameter of lossy grounds and antenna height have a direct influence on the antenna gain of both LPDA and MLPDA.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.21 no.7
• /
• pp.37-45
• /
• 2007

Recently, there has been an increase of the use of ground system for lightning protection called deeply driven grounding electrode. In the case of deeply driven grounding electrode, the rod electrode is equipped perpendicularly and deeply, therefore, it has a benefit to have less restriction of place compared to mesh grid electrode. However, ground impedance is largely changed by the local earth resistivity, so it requires a detailed analysis of the ground structure when planning. The measurement of earth resistivity by existing Wenner's method has been widely used, however, this method can not find out a change in the local ground resistance and it shows the result outwardly to be difficult to estimate exact depth. Therefore, this study analyzed the ground structure as 2-D image using 96 channels measurement facility and tried to analyze change in the local ground resistance and depth of the ground in order to design a deeply driven electrode effectively for lightning protection. It used Wenner alpha method dipole-dipole method and Schlumberger method for 2-D image analysis of the ground resistivity ma based on, it the result was compared with the ground structure analyzed with the result using the CDEGS and Wenner 1-D method.

• Journal of the Korean Geophysical Society
• /
• v.6 no.3
• /
• pp.179-188
• /
• 2003

The object of grounding of electrical facility is to protect human and machine damage from the power supply interruption high voltage by use of the accident current dissipating into the ground. Generally, it is not easy to make suitable ground design for inhomogeneous subsurface geology and the variability of accident current in magnitude and duration time. To make efficient ground, ground potential rise must be controlled in the way of overall lowering and evenness. This study shows the case of optimized ground design by use of subsurface resistivity structure from electrical soundings.

• Korean Journal of Soil Science and Fertilizer
• /
• v.42 no.2
• /
• pp.88-97
• /
• 2009

This study was conducted to obtain the basic information to increase the practical use of soil survey data through the subdividing of lava shapes with soil sequences due to different elevations in Jeju. The numbers of soil series of lava topography had occupied many of whole soil series in Jeju. When its topography subdivide, it give more detailed soil information. The obtained results are as follows; The lava topography to subdivide lava topography were studied with 38 soil series according to elevation in Jeju. Division of elevation are less than 50m, 50m to 200m, and 200m to 400m and more than 400m. Name the depending on elevation, less than 50m is called lower part of lava, 50m to 200m is called middle part of lava, and 200m to 400m and more than 400m are called upper part of lava. The characteristics of lava subdivide are as follows; soil family texture of lower part of lava is fine silty to clayey, drainage classes are various, average of available soil depth is 75.3cm, average of gravely contents are 11.6%, average of slopeness is 7.2%, limiting factor are various and soil order are various. soil family texture of middle part of lava is fine silty to coarse silty, drainage classes are well to very well, average of available soil depth is 65.9cm, average of gravely contents are 14.7%, average of slopeness is 11.3%, limiting factor are ashy and soil order are Andisols and Inceptisols. Soil family texture of upper part of lave is fine silty, drainage classes are well, average of available soil depth is 72.8cm, average of gravely contents are 16.0%, average of slopeness is 14.9%, limiting factor are ashy and skeletal, and order are Andisols.

• Journal of the Korea society of information convergence
• /
• v.5 no.2
• /
• pp.37-47
• /
• 2012

I generalized and analyzed the Supreme Court's judgements sentenced form Cho Sun High Court of Jus-tice to the present. Morever I tried to establish the system of a theory for surface rights from the viewpoint of the conventional law and present the direction in law-making political side. 1. The legal surface rights from the viewpoint of the conventional law have not been admited by the usage. Therefore I studied in detail its history, examples of foreign law-making, recognition authority and application object.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.7
• /
• pp.3460-3467
• /
• 2013

The In this paper, we have made numerical experiments to compare 2D image reconstruction algorithm of earth model by electrical resistance tomograpy (ERT). Gauss-Newton, simultaneous iterative reconstruction technieque (SIRT) and truncated least squares (TLS) approaches for Wenner and Schlumberger electrode arrays are presented for the solution of the ERT image reconstruction. Computer simulations show that the Gauss-Newton and TLS approach in ERT are proper for 2D image reconstruction of an earth model.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.22 no.4
• /
• pp.454-459
• /
• 2012

A kernel function of apparent earth resistivity can be estimated using the apparent earth resistivity measured with Wenner's 4 point method. It becomes to solve a nonlinear system to estimate the kernel function of apparent earth resistivity. However it is not simple to get solution of nonlinear system with many unknown variables. This paper suggests the method of estimating kernel function by linearizing this nonlinear system. Finally, various examples of earth structure have been simulated to evaluate the proposed method in this paper.

• Electric Engineers Magazine
• /
• v.174 no.2
• /
• pp.32-39
• /
• 1997

접지란 낮은 전기저항으로 전기설비를 대지에 접속하는 것을 말하며 전기적 성질히 전혀 다른 접지전극 토양입자, 물, 공기로 이루어진 대지를 전기적으로 접속한다는 것은 매우 어려운 문제이며 또한 접지의 특징이다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.3
• /
• pp.119-126
• /
• 2005

Electrical resistance tomography(ERT) maps resistivity values of the soil subsurface and characterizes buried objects. The characterization includes location, size and resistivity of buried objects. In this paper, Gauss-Newton, truncated least squares(TLS) and simultaneous iterative reconstruction technique(SIRT) methods are presented for the solution of the ERT image reconstruction. Computer simulations show that the spatial resolution of the reconstructed images by the TLS approach is improved as compared to those obtained by the Gauss-Newton and SIRT method.

• Journal of IKEEE
• /
• v.22 no.4
• /
• pp.1152-1157
• /
• 2018

In this paper, we try to solve the difficulties of the location of the structure for the movement of the wire - based pesticide spraying equipment designed for field farming. To do this, we apply earth resistivity measurement method and analysis technique which can indirectly grasp the earth structure. Electrodes are installed on the field in a selected farming area, and multi-switches built in the control board are driven to automatically acquire ground resistivity data. Then, the optimal point suitable for the actual structure installation is selected through the site analysis using the 2D image restoration algorithm.