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상용전원 주파수(60Hz)를 사용한 중전력 무선전력전송 연구 (Research on Medium-power Wireless Power Transmission using Commercial Power Frequency (60Hz))

  • 이기범
    • 한국전자통신학회논문지
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    • 제19권3호
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    • pp.497-506
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    • 2024
  • 본 논문에서는 상용전원 주파수(60 Hz)를 사용하여 중전력 무선전력전송을 구현한 것이다. 일반적인 자기유도 무선전력전송 장치는 수십 kHz 이상 사용하기 때문에 상용전원 주파수(60 Hz)를 그대로 사용할 수 없고, 교류/직류 변환기를 사용하여 60 Hz 전원주파수를 DC로 만들고, 고주파 파워앰프를 사용하여 DC를 수십 KHz로 만들어서 사용한다. 자기유도 무선전력전송에서 교류/직류 변환기와 고주파 파워앰프를 제거하고, 송전 공진탱크, 송전코일, 수전 공진탱크, 수전코일 만으로 구성한 상용전원 주파수를 사용하는 극저주파 무선전력전송 시스템을 구현하고, 무선전력전송 실험으로 검증하였다.

문자 인코딩 방식의 변화에 따른 트랜스포머 기반 침입탐지 모델의 탐지성능 비교 (Performance Comparison of Transformer-based Intrusion Detection Model According to the Change of Character Encoding)

  • 김관재;이수진
    • 융합보안논문지
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    • 제24권3호
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    • pp.41-49
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    • 2024
  • 트랜스포머 모델의 핵심 요소인 토크나이저는 숫자 형태의 데이터를 제대로 이해하지 못한다. 따라서 패킷 페이로드를 문장처럼 학습하여 실제 네트워크에서 동작 가능한 트랜스포머 기반의 침입탐지 모델을 구축하기 위해서는 16진수 형태의 패킷 페이로드를 문자 형태로 변환하는 것이 필요하다. 이러한 문제 인식 하에 본 연구에서는 3종의 문자 인코딩 방식을 적용하여 패킷 페이로드를 숫자 및 문자 형태로 변환한 후 트랜스포머 모델에 학습시키면서 모델의 탐지성능이 어떻게 달라지는지를 분석하였다. 성능 분석 실험을 위한 데이터세트는 UNSW-NB15 데이터세트에 포함된 PCAP 파일에서 패킷 페이로드를 추출하여 구성하였으며, 학습 모델은 RoBERTa를 사용하였다. 실험 결과, ISO-8859-1 인코딩이 이진분류 및 다중분류에서 가장 우수한 성능을 달성하는 것으로 확인되었으며, 토큰의 수를 512개로 설정하고 최대 에포크를 15회로 증가한 경우에 다중분류 정확도가 88.77%까지 향상되었다.

Protective Effect of Korean Red Ginseng Against Dichromate Toxicity

  • Kim, Eun;Hyun, Hak-Chul;Na, Ki-jung
    • 고려인삼학회:학술대회논문집
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    • 고려인삼학회 1990년도 Proceedings of International Symposium on Korean Ginseng, 1990, Seoul, Korea
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    • pp.132-136
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    • 1990
  • The metabolic disturbance and nephrotoxicity induced by sodium dichromate (20 mg/kg, SC) have been diminished by the administration of Korean red ginseng extract (100 mg/kg, PO). Red ginseng has a powerful potency on the blood urea nitrogen (BUN) increment shown in the early 2h after dichromate intoxication. It normalized the dichromate induced hepatic glycogenolysis. The effect of red ginseng on dichromate induced nephrotoxicity was investigated by hematological analysis, and urinalysis. Ginseng treatment significantly reduced the increases in the urinary excretion of protein and glucose. These effects were dose dependent. Ginseng protected the accumulation of BUN and cretonne in the blood, caused by dichromate intoxication. Unlike CaEDTA, ginseng did not change the urinary excretion chromium. And it could not convert htxavalent chromium to trivalent chromium. These results suggest that ginseng treatment is effective in decreasing the metabolic disturbance, one of the earliest signs of dichromate toxicity, resulting in the protective effect of dichromate induced renal damage.

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Biosynthesis of $\beta$-Lactam Antibiotics by Cell-free Extract from Lysobacter lactamgenus

  • Roh, Ju-Won;Nam, Doo-Hyun
    • Archives of Pharmacal Research
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    • 제15권3호
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    • pp.234-238
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    • 1992
  • Using cell-free extract of Lysobacter lactamgenus, enzymatic conversion of $\delta$-L-($\alpha$-aminoadiphyl)-L-cysteinyl-D-valine (ACV) the first substrate of $\beta$-lactam biosynthesis, into antibiotic compounds was attempted. In high performance liquid chromatographic (HPLC) analysis, the biosynthetic intermediates for cephalosporin antibiotics including isopenicillin N, deacetoxycephalosporin C, deacetylcephalosporin C and unknown cephem compound were detected in reaction mixtures. It implies that cephabacin compounds from L lactamgenus could be produced by biosynthetic routes through penicillin ring formation and its expansion to cephalosporin ring, likely as cephalosporin C from Cephalosporium or cephamycin C from Streptomyces. Among biosynthetic enzyme in cell-free extract, the ring formation activity (isopenicillin N synthetase activity) was separated in 50-60% of ammonium sulfate fraction, and ring expansion activity (deacetoxycephalosporin C synthetase activity) was found to be in 40-50% fraction. The partially purified isopenicillin N synthetase could convert as much as 90% ACV to isopenicillin N during 6-hour reaction.

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3D Visualization of Discrete Event Simulation and Its Applications in Virtual Manufacturing

  • Zhong Yongmin;Yuan Xiaobu
    • International Journal of CAD/CAM
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    • 제4권1호
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    • pp.19-32
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    • 2004
  • This paper presents a new approach to create 3D visualization from discrete simulation results. This approach connects discrete event simulation directly to 3D animation with its novel methods that analyze and convert discrete simulation results into animation events to trigger 3D animation. In addition, it constructs a 3D animation framework for the visualization of discrete simulation results. This framework supports the reuse of both the existing 3D animation objects and behavior components, and allows the rapid development of new 3D animation objects by users with no special knowledge in computer graphics. This approach has been implemented with the software component technology. As an application in virtual manufacturing, visualizations of an electronics assembly factory are also provided in the paper to demonstrate the performance of this new approach.

Fault Detection and Identification of Induction Motors with Current Signals Based on Dynamic Time Warping

  • Bae, Hyeon;Kim, Sung-Shin;Vachtsevanos, George
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제7권2호
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    • pp.102-108
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    • 2007
  • The issues of preventive and condition-based maintenance, online monitoring, system fault detection, diagnosis, and prognosis are of increasing importance. This study introduces a technique to detect and identify faults in induction motors. Stator currents were measured and stored by time domain. The time domain is not suitable for representing current signals, so wavelet transform is used to convert the signal; onto frequency domain. The raw signals can not show the significant feature, therefore difference values are applied. The difference values were transformed by wavelet transform and the features are extracted from the transformed signals. The dynamic time warping method was used to identify the four fault types. This study describes the results of detecting fault using wavelet analysis.

Relations among Security Models for Authenticated Key Exchange

  • Kwon, Jeong Ok;Jeong, Ik Rae
    • ETRI Journal
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    • 제36권5호
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    • pp.856-864
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    • 2014
  • Usually, key-establishment protocols are suggested in a security model. However, there exist several different security models in the literature defined by their respective security notions. In this paper, we study the relations between the security models of key establishment. For the chosen security models, we first show that some proven key-establishment protocols are not secure in the more restricted security models. We then suggest two compilers by which we can convert a key-establishment protocol that is secure in a specific security model into a key-establishment protocol that is still secure in a more restricted security model.

사진측량 기법을 사용한 어안렌즈 왜곡보정에 관한 연구 (A Distortion Correction Method for the Fish-Eye Lens using Photogrammetric Techniques)

  • 강진아;박재민;김병국
    • 한국측량학회:학술대회논문집
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    • 한국측량학회 2007년도 춘계학술발표회 논문집
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    • pp.161-164
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    • 2007
  • The paper studies in the wide-angle lens and distortion tendency and employs the correction techniques suitable to the fish-eye lens using the existing photographic survey methods. After carrying out the calibration of the the fish-eye lens, we calculated the correction parameters, and then developed the method that convert the original image-point to new image-point correcting distortion. The objectives of suggested calibration method in this paper are to calibrate the image of the the fish-eye lens used in the computer-vision and the control-instrumentation field widely. The proposed technique expects to improve the accuracy of the image of the fish-eye lens in the indoor tracking and monitoring field. Also the referenced cross point auto-extraction program is embodied for improving efficiency of the lens correction techniques. Consequently, this calibration method would be applied to the automated distorting correction method on not only the fish-eye lens also general lens.

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프리즘을 이용한 소형 단백질칩 분석 형광측정 시스템 개발 (Miniature Fluorescence Detection System for Protein Chips by Prism)

  • 최재호;김호성;이국녕;김은미;김용권;김병기
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 C
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    • pp.2040-2042
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    • 2004
  • This paper presents a miniature optical system for the fluorescence detection of the patterned protein chip. The patterned protein chip was fabricated using MEMS process. The fluorescence from the patterned protein chip was measured while varying the concentration of the BSA. The fluorescence light is separated spatially from the excitation beam using mini-size prism to increase SNR (Signal-to-Noise Ratio). The combination of prism and mirrors can convert the excitation light from the laser diode to uniform illumination on the specimen. We believe that the proposed system for fluorescence detection can be applied to rea1ization of point-of-care.

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배가스 펄스코로나 처리공정 실험설비용 20 kW급 자기펄스압축형(MPC) 펄스 모듈레이터 개발 (Development of a 20 kW pulse modulator for industrial application of pulse corona process)

  • 손윤규;장성덕;오종석;조무현;김민호;한병욱
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 C
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    • pp.1781-1783
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    • 2004
  • Flue gas from fossil fuel combustion is the main source of air pollution. It is recognized that $SO_2$ and $NO_x$, (sum of NO and $NO_2$) react with $H_2O$ and $O_2$ in atmosphere and convert precursors of acid rain. Streamer corona process using pulse power is one of the effective methods to remove these gases from stack. For this, pulse generator with 160 kV of output peak voltage, 0.3 ${\mu}s$ of pulse width and 120Hz of pulse repetition rate is developed. This paper shows the pulse compression characteristics to obtain optimum parameters for basic system design.

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