• Title/Summary/Keyword: VLF

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An Amendment of the VLF tanδ Criteria to Improve the Diagnostic Accuracy of the XLPE-insulated Power Cables (XLPE 절연케이블의 열화진단 정확도 향상을 위한 VLF tanδ 판정기준 개선)

  • Lee, Jae-Bong;Jung, Yeon-Ha
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.9
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    • pp.1644-1651
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    • 2010
  • VLF $tan{\delta}$ diagnosis technology is introduced in IEEE Std 400 and proposed as evaluation criterion in an effective way of detecting water tree which mainly causes the failure of XLPE insulated cables. In order to inspect the accuracy of the VLF $tan{\delta}$ method for XLPE insulated power cables in Korean distribution system, diagnosis for 41 cables which were being serviced in the fields has been carried out and they were removed for AC breakdown voltage test after. Regarding the 41 cables, it was hard to confirm any relation between the VLF $tan{\delta}$ values and AC breakdown voltages and also water tree in the insulation was not detected. However, the other cables were failed several days after the diagnosis of the 41 cables. Water trees were found and their VLF $tan{\delta}$ values were also much higher than the criterion of IEEE standard. It has been ascertained that we need to change the IEEE criteria in order to improve the accuracy of detecting water trees by additional analyzing of field examples of failure and case studies from overseas countries and therefore amended VLF $tan{\delta}$ test voltage and evaluation criteria have been proposed.

Emotion Recognition Method of Competition-Cooperation Using Electrocardiogram (심전도를 이용한 경쟁-협력의 감성 인식 방법)

  • Park, Sangin;Lee, Don Won;Mun, Sungchul;Whang, Mincheol
    • Science of Emotion and Sensibility
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    • v.21 no.3
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    • pp.73-82
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    • 2018
  • Attempts have been made to recognize social emotion, including competition-cooperation, while designing interaction in work places. This study aimed to determine the cardiac response associated with classifying competition-cooperation of social emotion. Sixty students from Sangmyung University participated in the study and were asked to play a pattern game to experience the social emotion associated with competition and cooperation. Electrocardiograms were measured during the task and were analyzed to obtain time domain indicators, such as RRI, SDNN, and pNN50, and frequency domain indicators, such as VLF, LF, HF, VLF/HF, LF/HF, lnVLF, lnLF, lnHF, and lnVLF/lnHF. The significance of classifying social emotions was assessed using an independent t-test. The rule-base for the classification was determined using significant parameters of 30 participants and verified from data obtained from another 30 participants. As a result, 91.67% participants were correctly classified. This study proposes a new method of classifying social emotions of competition and cooperation and provides objective data for designing social interaction.

A Study on the Correlation of the accompanying symptoms, Heart Rate Variability and Body Component Analysis in 350 Insomnia Patients (불면환자 350명의 동반증상과 심박변이도, 체성분 분석의 연관성에 관한 연구)

  • Ha, Ji-Won;Kim, Bo-Kyung;Jung, Jin-Hyeong
    • Journal of Oriental Neuropsychiatry
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    • v.23 no.3
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    • pp.47-62
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    • 2012
  • Objectives : This study is to figure the relations of the heart rate variability, body component analysis and accompanying symptoms of 350 insomnia patients. Methods : For this study we evaluated Heart Rate Variability(HRV) and body component analysis on 350 insomnia patients who visited Dongeui oriental hospital of Dongeui university from January 2008 to March 2012. The accompanying symptoms was collected based on each patient's progress note. Results : 1. There was no difference between PR, LF and VLF of male and female groups. HF was higher in the patients' of female group and LF/HF ratio was higher in the male group. The patients' group of age under 39 had higher HF, LF, VLF and LF/HF ratio than the group over 39. 2. The average of LF was the smallest, and the average of VLF was in the middle, while the average of HF was the largest. 3. Regarding patients' age and gender, as the patients' age increased, their HF, LF, VLF and LF/HF ratio decreased significantly. HF, LF, VLF, and LF/HF ratios were, however, independent on the patients' gender. As the patients' age increased, their BMI increased, while the patients' gender did not affect on their BMI. The amount of visceral fat increased with the patients' age, but wasn't dependent on the patients' gender. 4. As the patients' BMI increased, PR and LF decreased. As the patients' amount of visceral fat increased, PR, HF, LF and VLF decreased. 5. The most frequent accompanying symptoms of the insomnia patients was headache. Neither HF nor LF/HF ratio was dependant on any of the accompanying symptoms. Patients with anxiety showed significantly higher LF than those without anxiety. Patients with fatigue and physical pain showed significantly higher VLF than those without either of them. Conclusions : The study showed that as the insomnia patients age increased, the HF, LF, VLF, LF/HF ratio significantly decreased, but the BMI and visceral fat increased. The HF, LF, VLF, LF/HF ratio BMI, or the visceral fat was independent on the gender. As BMI increased, PR and LF decreased. As visceral fat increased, PR HF, LF and VLF decreased. Patients presenting anxiety had higher LF. Patients either with fatigue or physical pain had higher VLF. Neither HF nor LF/HF ratio had any significant correlation with any of the accompanying symptoms.

Shallow Eelectrical Resistivity and VLF Profiling at Sangchon-ri Area along the Southern Par of Yangsan Fault (양산단층 남부 상천리 일대의 천부 전기비저항 및 VLF 탐사)

  • 경재복;한수형;조현주;김지수
    • The Journal of Engineering Geology
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    • v.9 no.1
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    • pp.59-68
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    • 1999
  • To clarify the geological structure of Yangsan fault around Sangchon-ri in the southern part of Kyungsang Basin the resistivity (dipole-dipole profiling) and VLF surveys carried out on the four profiles, crossing the inferred trace of the fault. The resistivity contrast across the fault is clearly shown on the profiles: higher resistivity and lower resistivity on the east and west, respectively. It is most likely from the uplift of the granitic bedrock on the east park due to the strike-fault raulting with vertical movement. The zero-crossing points of VLF anomalies, associated with near-surface fracture zone, are found to well correlate with the resistivity boundaries from the dipole-dipole profiling. Consequently, southern segment of Yangsan fault (at Sangchon-ri area) is interpreted to be vertically developed strike-slip fault with a difference more than 10m depth of basement rock at both sides.

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Simple Interpretation of VLF Data (VLF 전자탐사 자료의 해석)

  • Kim Hee Joon;Nam Myung Jin;Song Yoonho;Suh Jung Hee
    • Geophysics and Geophysical Exploration
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    • v.8 no.2
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    • pp.184-190
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    • 2005
  • We have attempted to give some physical into the factors that control the response of subsurface target to plane wave excitation at VLF (very low frequency) frequencies. Although the VLF technique has some serious disadvantages, such as a lack of penetration depth and limited frequencies, its advantages are also extremely important to have made it by far the most popular electromagnetic technique in current use. In the magnetic-field measurement mode these lightweight, relatively low-priced tools allow us to survey large areas rapidly and inexpensively, to locate and roughly define subsurface electrical conductors. When used in the electric-field mode the technique is, in simple environments, capable of quantitative interpretation and once again the speed and relative cheapness of these devices makes them a natural 'first electromagnetic tool ' to use in reconnaissance mapping.

The SP/VLF Methodology to Confirm the Seawater Seepage Zone of the Embankment (방조제(防潮堤) 누수부위(漏水部位) 확인(確認)을 위한 SP/VLF 탐사법(探査法)의 적용성(適用性))

  • Cho, Jin-Dong;Jung, Hyun-Key;Chung, Seung-Hwan;Kim, Jung-Ho
    • Economic and Environmental Geology
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    • v.29 no.5
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    • pp.623-627
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    • 1996
  • Combined SP/VLF surveys were carried out at tide embankment, Changgi-ri, Anmyeon-up, Chungcheongnamdo in order to confirm the seawater seepage zone of the embankment using the 128 Channels SP monitor system and VLF/Magnetometer system. These methods were successful in the detection of the seawater seepage zone. The self-potential method can give better resolution of the seepage zone than do VLF method.

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A Statistical Analysis to the VLF Tanδ Criteria for Aging Diagnosis in Power Cables (전력케이블 열화진단을 위한 극저주파 탄델타 판정기준의 통계적 해석)

  • Jung, Woosung;Kim, Seongmin;Lim, Jangseob;Lee, Jin
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.33 no.1
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    • pp.1-5
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    • 2020
  • In this study, the objective is to improve the criteria used for statistical comparison of the VLF tanδ (TD) database and failure rate according to water-tree degradation in underground distribution power cables. The aging condition of the KEPCO criteria is divided into 6 levels using the Weibull distribution, and the "failure imminent" condition is quantified by using the statistical end-point of the lifetime parameter of the VLF big-data group obtained from KEPCO. Moreover, new criteria with a 2-dimensional combination of TD, DTD, and a statistical normalized factor are suggested. These criteria exhibit high reproducibility for the detection of cables in an imminent failure state. Consequently, it is expected that the adoption of the extended VLF-2019 criteria will reduce the asset management cost of cable replacement compared to the VLF-2012 criteria of KEPCO.

Molecular Cloning and Characterization of Very Late Expression Factor 1 Gene, vlf-1 from Bombyx mori Nuclear Polyhedrosis Virus Kl

  • Park, Hye-Jin;Lee, Kwang-Sik;Cho, Eun-Sook;Yun, Eun-Young;Kang, Seok-Woo;Kim, Keun-Young;Sohn, Hung-Dae;Jin, Byung-Rae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.1 no.1
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    • pp.29-33
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    • 2000
  • We cloned and characterized a very late expression factor 1 gene, vlf-1, which regulates the level of very late gene transcripts, from Bombyx mori nuclear polyhedrosis virus (BmNPV) K1 strain. The 1,140 bp vlf-1 has an open reading frame of 379 amino acid and a MW of 44 kDa. The vlf-1 nucleotide sequence of BmNPV-Kl showed high homology with Autographa californica nuclear polyhedrosis virus and BmNPV T3 strain so far known, and its deduced amino acid residues were identical to those of BmNPV T3. The location of vlf-1 in the BmNPV-Kl genome was confirmed by Southern blot analysis and its expression patterns at the transcriptional level were confirmed by Northern hybridization analysis.

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Implementation of Power Cable Diagnostic Simulator using VLF (VLF를 활용한 전력케이블 진단 시뮬레이터 구현)

  • Kim, Kuk;Eo, Ik-soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.8
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    • pp.593-602
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    • 2020
  • Power cables installed in domestic factories or underground can cause accidents depending on the manufacturing process, installation, and environmental conditions during use. When an accident occurs in a power cable, it can cause enormous economic loss and social confusion. Hence, the importance of preventive management of the cable through diagnosis is increasing to prevent it. Therefore, in this paper, a diagnostic sample cable was produced by simulating a part that could be a problem due to the installation, manufacturing defects, or deterioration of cables that can occur in the field. Dielectric loss Tangent (tan 𝛿; TD), and Partial Discharge(PD) tests were performed. Partial discharge and AC (60Hz) withstand voltage equipment using High-Frequency Current Transformer (HFCT) were applied After applying a VLF (Very Low Frequency) power supply with a frequency of 0.1Hz was applied. As a result, B and C phase defect samples at a 2.0U0 voltage through the VLF could measure the internal partial discharge in the A-phase normal sample cable from the noise at a 0.5U0 to 2.0U0 voltage. In addition, the 1.5U0 voltage was measured through the AC (60Hz) withstand voltage equipment of the commercial frequency to verify its effectiveness. Partial discharge in the run-off state was measured at a voltage of 1.0U0, and there was a risk when installing the equipment. AC power equipment showed a difficulty of movement by volume or weight. The diagnostic method, through the VLF of the quadrant state, revealed its safety and effectiveness.

Construction and Characterization of Transformed Insect Cells Expressing Baculovirus Very Late Factor in an Infection-Independent Manner

  • Park, Hye-Jin;Lee, Kwang-Sik;Cho, Eun-Sook;Yun, Eun-Young;Kang, Seok-Woo;Kim, Keun-Young;Sohn, Hung-Dae;Jin, Byung-Rae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.2 no.1
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    • pp.19-26
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    • 2001
  • Transformed Spodoptera frugiperda (Sf9) cells expressing baculovirus very late factor (VLF-1) were constructed by using Autograha nuclear polyhedrosis virus (AcNPV) immediate earthy gene (ie1). Neomycin-resistance gene as a selectable marker was introduced under the control of AcNPV ie1 promoter, and Bombyx mori nuclear polyhedrosis (BmNPV-K1) vlf-1 gene was introduced under the control of the Drosophila heat shock protein gene (hspr70) promoter to yield dual expression plasmid with two independent transcription units. It was transfected into Sf9 cells and cell clones expressing vlf-1 were selected by G4l8 treatment. Genomic DNA from transformed cells was isolated and integration of AcNPV iel harboring vlf-1 was confirmed by PCR using AcNPV iel-specific primers and Southern blot analysis. The transformed cells expressing VLF-1 in an infection-independent manner expressed foreign gene product of recombinant baculovirus in the earlier stage of infection compared with control Sf9 cells. These results suggest the possible to develop highly efficient transformed insect cells for baculovirus expression vector system.

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