• Geophysics and Geophysical Exploration
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• v.1 no.2
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• pp.87-91
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• 1998

Geophysical survey techniques, such as electromagnetic(EM), GPR, and electrical method, have been tested in the landfill area to evaluate the applicability of these methods to soil contamination measurement. The EM method has proven to be excellent on mapping the areal distribution of contaminants and the migration path for leachate. Since the field operation of EM technique is simple as well as fast, we think the EM method must be the first choice for these purposes. Electrical survey techniques have proven to be very effective on mapping sectional distribution of contaminants. Generally, the GPR method is very good on high resolution survey of shallow depth, and field data acquisition is simple, too. But the resistivity method gives better information on deep area, for example, deeper than the depth of 20 m.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.422-431
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• 2003

Helicopter-borne electromagnetic (HEM) systems were originally developed for the exploration of mineral deposits. The frequency range of a conventional HEM system for mineral exploration, however, is relatively low and so not invariably suitable for its application to the fields of civil engineering because of its poor resolution in the shallower part of the earth. A DIGHEM HEM system was acquired by Nippon Engineering, with the frequencies chosen by the senior author. The five frequencies range from 220 Hz (the lowest) to 137,500 Hz (the highest). These frequencies improve the resolution of materials in the shallower part while maintaining a depth of investigation of greater than 100 m. This paper describes six case histories of geological and geotechnical surveys for civil engineering using HEM. These case histories include HEM surveys for investigating landslide, an alluvial area, root selection of road construction, areas related to dam and tunnel construction, and the simultaneous joint inversion of HEM and CSAMT data for a deep tunnel. These survey results show that HEM has sufficient resolution in both horizontal and vertical directins to contribute significantly to outlining the regional geology and its engineering problems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.8
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• pp.934-941
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• 2012

This paper has examined the concept of dependence of spectrum to foresight on future wireless industry. For this, we classified the wireless industry and had a survey on the dependence of spectrum of the wireless industry by experts interview. We had foresighted the trend and changes of future market of wireless industry using survey data. We also had analyzed on factors of growth and level of development of wireless industry.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.7
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• pp.701-709
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• 2013

In this paper, we studied a policy direction for promoting wireless industry. For this, we defined the concept of wireless industry and classified their structure and suggested a growth model of wireless industry and policy elements, which is composed of technology development, service development, advancement of law and regulations, business model development, assistance of production and use, publicity enforcement for promotion. Also, we had a survey on the policy elements for promoting the industry by experts interview. We drew some policy directions for promotion of wireless industry from survey results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.8
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• pp.589-602
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• 2017

In this paper, we analyzed on the importance of radio spectrum and radio industry for promoting radio ecosystem. For this, we investigated the changes of future society and analyzed the recognition and importance of radio industries by survey on opinion changes of experts. We suggested a direction for radio industry promotion, which is composed of technology development, service development, advancement of law and regulations, business model development, assistance of production and use, publicity enforcement for promotion. The importance changes and radio use industry sector practices of the radio industry are analyzed by survey of experts. From this result, the 5 policy options are proposed.

• Geophysics and Geophysical Exploration
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• v.27 no.1
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• pp.57-68
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• 2024

Offshore wind power is increasingly regarded as a viable solution for reducing greenhous emissions due to the construction of wind farms and their superior power generation efficiency. Submarine power cables play a crucial role in transmitting the electricity generated offshore to land. To monitor cables and identify points of failure, analyzing the location or depth of burial of submarine cables is necessary. This study reviewed the technology and research for detecting submarine power cables, which were categorized into seismic/acoustic, electromagnetic, and magnetic exploration. Seismic/acoustic waves are primarily used for detecting submarine power cables by installing equipment on ships. Electromagnetic and magnetic exploration detects cables by installing equipment on unmanned underwater vehicles, including autonomous underwater vehicles (AUV) and remotely operated vihicles (ROV). This study serves as a foundational resource in the field of submarine power cable detection.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.673-681
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• 2014

Recently, many countries in the world try to develop alternative energy sources, however, traditional hydrocarbon resources are still occupying most of the energy resources. Exploration demands for high technologies are increasing in the development of limited oil & gas resources field owing to the exhaustion of hydrocarbon resources for access area. Therefore, an effort for the development and the application of new technologies such as azimuth seismic survey, ocean-bottom seismic survey and marine controlled-source electromagnetic survey is necessary as well as an understanding of the existing technologies such as 2D/3D seismic survey. This dissertation is designed with the purpose of introducing marine hydrocarbon exploration technologies and analyzing their internalexternal researches, development and science information. In this study, we analised total 616 dissertations for the marine petroleum exploration released in the Sci-expanded DB of 'web of science' during the 2001~2014 periods.

• Geophysics and Geophysical Exploration
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• v.6 no.3
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• pp.143-152
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• 2003

Among the various geophysical approaches to identify the leakage of leachate with conductivity variation, conventional electrical resistivity survey has been mainly used at waste landfill. We adopted small-loop electromagnetic (EM) survey using multi-frequencies in parallel with electrical resistivity survey to delineate the leakage of leachate through the shallow soil layer at a waste landfill in Jeju Island, and also with self-potential monitoring to detect the streaming potential produced by the movement of leachate. There were no evidences of leakage from waste landfill according to the results of the electrical resistivity survey and SP monitoring, and it was also true from the results of water quality analysis at stream around waste landfill periodically. On the other hand, the results of one-dimensional inversion of spatially-filtered small-loop EM survey data showed the anomalous zone of low resistivity with depth both around and inner waste landfill.

• Journal of the Korean Geophysical Society
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• v.5 no.2
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• pp.99-109
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• 2002

Among the geophysical exploration methods, electromagnetic method(EM) has the broadest range of instrumental systems and remarkable range of applications. There are a lot of available techniques and instruments which have different depth of investigation and resolution depending on the operating frequency and source-receiver configuration. Furthermore, it is very easy to apply on the engineering and environmental problems since modern EM equipments are remarkably portable, considering their sophistication. Even though electromagnetic theory is very complex and not easy to understand, rapid avances in recent computer technology have made it possible to conduct accurate forward modeling and inversion of various EM exploration data. Here, we are going to provide brief theoretical principles, survey techniques and case histories of some selected EM methods that can be applied to geotechnical and environmental problems in Korea.

• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.61-66
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• 2017

It is very important to understand the electromagnetic characteristics of underground media in GPR (Ground Penetrating Radar) survey. Depending on the electrical characteristics of the underground medium, the energy of the electromagnetic wave becomes relatively small, and reflection from the interface may become difficult. In this study, electrical characteristics of sandy soils under various (loose and dense) conditions were analyzed. As a result, In dry sand is the dielectric constant increased as the relative density increased, and the dielectric constant and electrical conductivity increased as the moisture content of the sand increased.