• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.335-339
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• 2003

The estimation of seawater intrusion into deep aquifers has been becoming an important subject in terms of site characterization for geological disposal of radioactive waste. Conventional direct-current resistivity methods have been used for ground water explorations and recently have been applied to environmental problems. However, electromagnetic methods are more practical and useful for such a deep investigation. We consider audio-frequency magnetotelluric (AMT) and surface-to-borehole electromagnetic (EM) tomography methods as promising tools for the investigation of deep aquifer. These methods were tested in the Hasunuma area, Chiba Prefecture, Japan. Although the study area is in an urban area, high-quality AMT data were acquired, which was mainly accomplished by night-time data recording and remote-reference data processing. One-dimensional inversion results of the AMT data revealed two extremely conductive zones, which is consistent with the electrical conductivity profile of pore water in core samples. It can be interpreted as the seawater intrusions into both zones. However, the chemical analysis of the groundwater sampled in the deep zone suggests that this groundwater must be fossil seawater that had been confined during sedimentation processes. In addition, the permeability coefficient of the deep layer is very low. Thus the deep conductive zone corresponds to the fossil seawater regarded as being difficult to flow.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.8
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• pp.699-709
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• 2015

The role of wireless power transmission(WPT) on the information communication technology and the re-set location of WPT technology in the hype cycle to apply the recent trend of market and industry are presented in this paper. We describe the need of national strategy to change from the phase of industry promote to the phase of industry revitalization. The relation between the management of spectrum and electromagnetic environment is analysed in the view point of physics. We also propose the direction of policy for industry revitalization adapted the world changing circumstance.

• Journal of the Korean Geophysical Society
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• v.6 no.4
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• pp.231-244
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• 2003

Lots of various utilities are buried under the surface of the earth. The effective handling of the underground utilities is becoming the big subject and project for the harmonious management and administration of the city. To detect the position and depth of buried underground utilities, GPR and Induced EM surveys are commonly used. However, they have limitations, such as shallow skin-depth and non-availability in the areas where subsurface materials are not homogeneous and are compose of clays and/or salts and gravels. The aim of this study is to find the efficient geophysical method which can overcome these limitations. For this purpose, various geophysical mehods were applied in the site of poor geotechnical environment.

• Proceedings of the Safety Management and Science Conference
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• 2010.11a
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• pp.41-61
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• 2010

With increasing the quality of life in proportion to the national income, we have had cars as more convenient and safe means of transportation for a long time. The more we have the benefits from cars, the more seriously we should consider problems such as the destruction of the environment by air pollution, traffic accidents, parking problems, traffic congestion, etc. as social cost caused by the increase of cars. Among them, the traffic accidents are very serious, especially the accidents of the business cars occurs five times more than those of the private cars. Therefore if we analyze the cases of the various kinds of syst.em, test the results and apply them to business cars, we will reduce the traffic accidents of business cars.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.23-27
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• 2004

Developing of electromagnetic wave absorbers for GHz frequency, we used cast Alnico magnets. It is the first research paper to show that electromagnetic wave absorbers with Alnico magnets have good reflectivity in the GHz frequencies. Especially in this study, we used recycled cast Alnico magnets for natural resources problems and natural environment problems. New electromagnetic wave absorbers developed in this study are useful for X-band and C-band.

• Proceedings of the KIEE Conference
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• 2003.07e
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• pp.117-119
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• 2003

Recently, Radio Frequency Identification (RFID) cards have been charming increasing attention. In addition, the RFID card ensures high durability and ease of maintenance because it has no built-in contact. And the benefits of RFID cards over contact cards are primarily due to the increased transaction speed and convenience brought to the cardholder. In this paper, we have developed a RFID card reader for the multi-purpose applications. The vicinity card reader with large-screen to display user ID and card number for a kinds of applications such as entrance and attendance management system is suitable for the use with EM card and TEMIC card, featuring easy to mount and reliable quality. The read range of the proposed RFID card reader is 70cm. This paper also addresses current RFID technology in terms of systems and provides a look forward its future applications in the aviation environment using RFID smart card.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.43.1-43.1
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• 2009

Electromagnetic radiation at the plasma frequency and its second harmonic, the so-called plasma emission, is fundamental process responsible for solar type II and III radio bursts. There have also been occasional observations of higher-harmonic plasma emissions in the solar-terrestrial environment. We will present that the simulation effort on characterizing the electron beam-generated plasma emission process at POSTECH. We have developed fully electromagnetic particle-in-cell (PIC) simulation code with three dimensions. We simulated harmonic plasma emission with various beam condition. Qualitative comparison with the traditional plasma frequency and second harmonic radiation theory is in good agreement. Higher harmonic emissions agree with the theory of coalescence of Langmuir and harmonic EM wave.

• Proceedings of the Korea Information Processing Society Conference
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• 2024.05a
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• pp.617-618
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• 2024

본 논문에서 핵심적으로 연구할 내용은 기존 논문에서 소개된 BERT-base 모델의 경량화 버전인 DistilBERT 모델을 임베디드 시스템(Raspberry PI 5) 환경에 탑재 및 구현하는 것이다. 또한, 본 논문에서는 임베디드 시스템(Raspberry PI 5) 환경에 탑재한 DistilBERT 모델과 BERT-base 모델 간의 성능 비교를 수행하였다. 성능 평가에 사용한 데이터셋은 SQuAD(Standford Question Answering Dataset)로 질의응답 태스크에 대한 데이터셋이며, 성능 검증 지표로는 EM(Exact Match) Score와 F1 Score 그리고 추론시간을 사용하였다. 실험 결과를 통해 DistilBERT와 같은 경량화 모델이 임베디드 시스템(Raspberry PI 5)과 같은 환경에서 온 디바이스 AI(On-Device AI)로 잘 작동함을 증명하였다.

• Journal of Microbiology and Biotechnology
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• v.20 no.7
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• pp.1107-1113
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• 2010

Because conventional methods for detecting emetic-toxin-producing B. cereus are laborious and costly, various PCR assays, which are easy and cheap, have recently been reported. Therefore, this study estimated and compared the ability of various PCR assays to detect emetic-toxin-producing B. cereus strains isolated in Korea. The PCR assays were performed on 160 B. cereus strains, including 40 emetic-toxin-producing strains. Although the species-specific PCR assays were all shown to be highly specific, the sensitivities varied greatly. The accuracies of the primers were 97.5% (CER), 95.6% (EM1), 96.3% (RE234), 89.4% (CES), and 83.1% (Ces3R/CESR2). Moreover, the CER primer had a higher sensitivity (100%) than all the other primers tested, and a specificity of 96.7%. Thus, the CER primer was shown to be the most effective for screening the emetic-toxin-producing B. cereus strains tested in this study. However, the ability of these PCR assays to identify emetic-toxin-producing B. cereus should also be confirmed using other methods.

• Korean Journal of Environment and Ecology
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• v.21 no.3
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• pp.257-277
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• 2007

We carried out a phytosociological study on pine forests in Korea with the method of Zurich-Montpellier School. We collected the data of 252 $relev{\acute{e}}s$ from 45 sites in the pine forests throughout the Korean Peninsula and its attached islands. The vegetation of the pine forests was classified into one association, three communities and seven subcommunities as follows: A: Quercus mongolica-Pinus densiflora community, A-1: Typical subcommunity, A-2: Vaccinium korean urn subcommunity, A-3 : Rhododendron micranthum subcommunity, B: Quercus serrata-Pinus densiflora community, B-1: Typical subcommunity, B-2: Juniperus rigida subcommunity, B-3: Styrax japonica subcommunity, B-4: Eurya japonica subcommunity, C: Saso-Pinetum densiflorae Yim et al. 1990, and D: Castanopsis cuspidata var. sieboldii-Pinus densiflora community. The former three communities were integrated into the Lindero-Quercion mongolicae Kim 1990 em. 1992. The Castanopsis cuspidata var. sieboldii-Pinus densiflora community remained to be studied in future to determine the association. The communities of Quercus mongolica-Pinus densiflora community was distributed throughout the montane zone in central-northern part of the Korean Peninsula. Quercus serrata-Pinus densiflora community occupied widely in the sub-montane and hilly areas in central and Southern Korean Peninsula. The association of Saso-Pinetum densiflorae was found in Cheju Island. Castanopsis cuspidata var. sieboldii-Pinus densiflora community were distributed in the warm-temperate zone including islands off the south-west coast of the Peninsula.