• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.11
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• pp.532-537
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• 2006

Lightning induced faults accounts for more than 66% at the transmission lines of KEPCO. The lightning causes damages to power system equipments including transmission line, the blackout of electricity and the electro-magnetic interference. Because of this reason, we need the real time lightning information for the optimal operation of power system. And, it is required to obtain and accumulate the lightning current parameters for the insulation design. In 2005, KEPRI constructed a lightning detection network, the KLDNet (i.e. Kepco Lightning Detection & Information System) and launched a lightning information service for KEPCO customers. It is intended to provide data service on the operation of transmission lines and collect lightning-related data, which is the most important factor regulating power system design and operation. The new system will replace LPATS, the old detection system, which has been operating since 1995 and is rapidly failing in terms of both detection performance and location accuracy. The purpose of this paper is to explain the work performed and the results of that work in performing a site survey of several locations. The purpose of the site survey is to find locations acceptable for the installation of a lightning location receiver in support of a Lightning detection system(LDS). A restriction was placed on the surveyed locations, as they must belong to the Korea Electric Power Company. This requirement was made to facilitate the communication needs of the LDS network. Total of 15 sites were evaluated as possible LDS sensor sites. Some of the sites were rejected for physical reasons and therefore no electrical testing was performed. Of the 15 sites, total of 10 sites were considered acceptable and 5 sites were rejected for various reason. In this paper, we would like to explain the site survey and detection efficiency for LDS.

• Geosciences Journal
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• v.22 no.6
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• pp.891-902
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• 2018

Techniques for more reliable detection of 3D subsurface flow paths are highly important for most water-related geotechnical projects. In this case study, a magnetometric resistivity method with a new approach and state-of-the-art technology ("Willowstick survey") was applied to the testbed dam (YD dam) site, and its applicability was validated by geotechnical investigation techniques including borehole drilling and sampling, Lugeon test, flow direction and velocity test, and seismic tomography. In addition to the magnetometric survey, a 3D electrical resistivity survey was performed independently and the results were compared and discussed. The electrical resistivity survey was effective in detecting groundwater levels, but it was limited in mapping leakage paths. On the other hand, the Willowstick magnetometric survey effectively detected geologic weaknesses (e.g., fault fracture) and potential leakage paths of the dam site foundation rocks. The results of this research are expected to be effective for water infrastructures where leakage is an important issue.

• Journal of Advanced Navigation Technology
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• v.24 no.4
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• pp.273-279
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• 2020

In the Korea's SBAS(KASS), reference site is an important infrastructure facility for the collecting and monitoring GPS/GEO signals. The SBAS reference station has an clear requirements than other regular monitoring stations. It requires constant maintenance during the system operation. The development for KRS site should be prepared for site survey, site construction, antenna geodetic survey, equipment installation and operation. Site survey is initially performed as an important step to predict site availability and system performance. The operation center must provide the reference site, equipment room, and appurtenant to satisfy the site requirements. The position of antennas is very important information, and accuracy must be secured through the geodetic survey. Measurement collected at the from precise antenna are provided to the KASS processing station. The position of antenna should be maintained through continuous position checks and updates during the operation. When the development of the KRS site is completed, it performs tasks for installing and operating the KRS equipment. In this paper, we presented the procedures and some results for the development of the 7 KRS sites.

• The Journal of Engineering Geology
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• v.22 no.4
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• pp.409-416
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• 2012

In this study, an electrical resistivity survey and a drilling investigation were conducted at an animal carcass disposal site. Chemical analysis of leachate collected from the site was also performed (sampling times: May 2011 and June 2012). Five lines of dipole-dipole electrical resistivity surveys were carried out, along with drilling investigations at 3 points within the disposal areas and 11 points near the disposal site. Two-dimensional inverse modeling of the collected resistivity data was performed to evaluate the properties (size, depth, and form) of the disposal site. Leachate analysis showed that pH of leachate decreased from 7.4 to 6.7, while Eh changed from -358 mV to -48 mV over time. In addition, dissolved ions increased due to the progression of carcass decomposition. Results of the electrical resistivity survey indicated that low resistivity zones (minimum value, $0.64{\Omega}m$) existed at a depth of 8 m from the surface. Considering the bedrock location and carcass disposal depth, there was no evidence of bedrock contamination by leachate. The results of the electrical resistivity survey are consistent with those of the drilling investigation, which indicates that electrical resistivity effectively depicted the properties of the disposal site. This study demonstrates that electrical resistivity survey is a suitable technique for investigation of animal carcass disposal sites.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.3
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• pp.10-18
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• 2001

The existing measurement system to ground-surface displacement survey of the slope has been including the hazard for the measure in site and the difficulty for install, maintenance and control of expensive instruments, which are impossible of whole survey on the slope surface. To overcome of those defects, Softcopy Photogrammertry method is used, which can measure displacement of ground-surface on the slope and structure deformation vectors. Recently, the survey methods applying the advantages of Photogrammetry and Digital Photogrammetry Survey are widely used. In this study, therefore, the development and application of the new instrument mechanism on the the site example are studied. Through the application of Softcopy Photogrammetry, the 3-D data of ground surface on the dangerous slope could be effectively obtained at the long distance, which are obtained through the reform process of contour line. Those are different to the results of the Close-Range Photogrammetry analysis. In ground instrumentation parts, the new practical system shall be the technical base to improve of the instrument machine as well as can be widely applied in civil engineering and others branch.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.1
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• pp.119-128
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• 2014

The environmental survey in advance in the construction works is very important for planning and designing as well as the service of field survey before carrying out construction. The topographical application of spatial information coupled with USN is the very economical method for the survey and research every processing stage of construction field in advance. Therefore the execution of very important role for environmental planning and fundamental designing of construction reduces the unnecessary trial and error through the environmental survey in advance. In this research the environment of existent construction field is transformed to that of digital spatial information by fusing the sensor network with wireless technique on the base of spatial position. In addition, the sink sensor cumulates the environmental data measured from each USN sensor using small wireless environmental sensors installed at the construction site and changes of various environmental data at the present constructing site are able to be monitored at 3-D topographical space in real time by using the method for transmitting the image of PC output based on TinyOS.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.575-587
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• 2013

DC electrical and electromagnetic survey was applied to evaluate the reserve of an iron mine site. We analyzed the borehole cores and the cores sampled from outcrops in order to decide which geophysical method was efficient for the evaluation of iron mine site and to understand the geological setting around the target area. Based on the core tests for specific weight, density, porosity, resistivity and P-wave velocity, showing that the magnetite could be distinguishable by the electrical property, we decided to conduct the electrical survey to investigate the irone mine site. According to previous studies, the DC electrical survey was known to have various arrays with high resolutions effective to the survey of the iron mine site. However it was also known that the skin depth is too shallow to grasp the deep structure of iron mine. To compensate the weakness of the DC electrical method, we applied the MagnetoTelluric (MT) survey. In addition, a Controlled Source MT (CSMT) method was also applied to make up the shortcoming of MT method which is weak for shallow targets. From the DC electrical and MT survey, we found a new low resistivity zone, which is believed to be a magnetite reserve beneath the old abandoned mine. Therefore, this study was confirmed for additional utility value.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.37-44
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• 2010

Recently, urban retrofit and extension, development of new buildings and facilities, and construction of underground structures like subway tunnels in urban areas give rise to significance of site investigation at urban areas. However, ambient electric noises, traffic vibrations, embedded objects work as obstacles to high-quality and accuracy in site investigation at urban areas. In this paper, a new technique called the pseudo-DC resistivity survey (in brief, PDC-R) was proposed to minimize the adverse effect of ambient electrical noises in resistivity survey. PDC-R technique utilizes an AC current with frequency range of 0.1 to 1.0 Hz rather than DC current, which is used for conventional resistivity survey. The motivation of using low-frequency AC current is to avoid 60-Hz components or its multiples in the resistivity survey which ambient noises are mostly composed of. The implementation of PDC-R technique also included the parametric study on skin effect, frequency effect and current-level effect, which led to the determination of optimal values of frequency and current level for PDC-R survey. The reliability and feasibility of PDC-R technique was verified through field tests, accompanied by the comparison with DC resistivity survey and CapSASW tests.

• Journal of Korean Society for Quality Management
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• v.45 no.2
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• pp.275-292
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• 2017

Purpose: This study is designed to explore web-site service quality factors in job information site for high quality human resource, and to test relationship among web service quality, image, user satisfaction, relationship quality, and loyalty intention. Methods: A survey tool was questionnaire that had obtained validity and reliability through literature survey and pretest survey, and sample 214 was analyzed through SEM using SPSS21.0 and AMOS21.0. Results: Web design and information offer affect Image and user satisfaction. Also, relationship quality turned out to be an important mediator between image and loyalty intention and between customer satisfaction and loyalty intention. Conclusion: This study shows that two factors in via of relationship quality, were important factors that related companies have to emphasize to raise performance, Also, in order to raise loyalty intention of customer, marketer should exert to well manage relationship quality having significance as a mediator.

• Economic and Environmental Geology
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• v.27 no.6
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• pp.563-569
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• 1994

Resistivity Image Profiling has been applied to a geological survey in the Keoje-do area. Survey lines are located near the KD-02 and KD-06 wells in the area, where we have already sampled all rock cores and carried out several kinds of geophysical logs. In each site a resistivity cross-section is obtained by inverting pole-pole apparent resistivities. Comparing the reconstructed resistivity section with the rock cores and logging data obtained in the well provides a detailed picture of subsurface geology. The geology of KD-02 site is composed of conglomerate, sandstone and shale with fractures. The reconstructed resistivity image is useful for assessing the grade of weathering of these rocks. The KD-06 site is mainly underlain by granitic rocks, and its fresh basement can be delineated by resistivities over $1000{\Omega}{\cdot}m$.