• 정보학연구
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• 제7권4호
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• pp.61-69
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• 2004

본 논문에서는 6.6kV급 고압전동기 모델 코일을 4가지의 권선의 인공적인 결함을 갖도록 제작하였다. 운전중 모의를 위해 모델 코일에 80pF의 에폭시-마이카 커플러를 설치하였으며, TGA를 사용하여 NQN, 부분방전 크기 및 부분방전 패턴 등을 측정하였다. 웨이블렛 변환기법을 이용한 고압전동기의 고정자권선의 결함에서 발생된 부분방전신호의 파형을 통하여 여러 가지의 통계적인 파라메터를 통하여 특징을 추출하였다.

• Journal of Electrical Engineering and Technology
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• 제5권1호
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• pp.140-145
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• 2010

The monitoring and the diagnosis of the faults in induction motors starting from the stator current are very interesting, since it is an accessible and measurable quantity. The spectral analysis of the stator current makes it possible to highlight the characteristic frequencies of the faults but in a wide frequency range depending on half the sampling frequency, making it very difficult to monitor on-line the faults. In order to facilitate the use of the relevant frequencies of machine faults we proposed the extraction of the frequency components using two methods, namely, the amplitude and the instantaneous frequency. The theoretical bases of these methods were presented and the results were validated on a test bench with an induction motor of 5.5 kw.

• 한국멀티미디어학회논문지
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• 제18권1호
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• pp.9-16
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• 2015

Various approaches to process active sonar signals are under study, but there are many problems to be considered. The sonar signals are distorted by the underwater environment, and the spatio-temporal and spectral characteristics of active sonar signals change in accordance with the aspect of the target even though they come from the same one. And it has difficulties in collecting actual underwater data. In this paper, we synthesized active target echoes based on ray tracing algorithm using target model having 3-dimensional highlight distribution. Then, Fractional Fourier transform was applied to synthesized target echoes to extract feature vector. Recognition experiment was performed using probabilistic neural network classifier.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2000년도 제13회 춘계학술대회 및 임시총회 학술발표 논문집
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• pp.855-857
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• 2000

본 논문에서는 하이라이트의 연관성을 이용한 분석 방법을 제안한다. 멀티미디어와 동영상 서비스의 발달과 더불어 운동 경기의 내용을 자동 분석하여 하이라이트 추출이나 방송 중계 등에 이용하고자 하는 시도가 많이 이루어지고 있다. 동영상은 텍스트나 정지 영상에 비해 방대한 데이터로 구성되어 있다. 그러므로 경기 내용을 효과적으로 파악하기 위해서는 내용 기반의 주요 경기내용(High light)만을 추출 디스플레이 하는 기술이 필요하다. 본 논문에서는 스포츠와 관련된 동영상에서 자동으로 하이라이트 부분을 검출하는 기법을 개발하였으며, 이 기법을 방송용 축구 경기 동영상에 적용하여 하이라이트 추출을 시도하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.77-79
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• 2019

Islanding detection is one of the most important issues for the distributed generation (DG) systems connected to the power grid. The conventional passive islanding detection methods inherently have a non-detection zone (NDZ), and active islanding detection methods may deteriorate the power quality of a power system. This paper proposes a novel hybrid islanding detection method based on Digital Lock-In Amplifier with no NDZ by monitoring the harmonics present in the grid. Proposed method detects islanding by passively monitoring the grid voltage harmonics and verify it by injecting small perturbation for only three-line cycles. Unlike FFT for the harmonic extraction, DLA HC have lower computational burden, moreover, DLA can monitor harmonic in real time, whereas, FFT has certain propagation delay. The simulation results are presented to highlight the effectiveness of the proposed technique. In order to prove the performance of the proposed method it is compared with several passive islanding detection methods. The experimental results confirm that the proposed method exhibits outstanding performance as compared to the conventional methods.

• Journal of information and communication convergence engineering
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• 제21권3호
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• pp.244-251
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• 2023

Engineering or humanities data are stored in databases and are often used for search services. While the latest deep-learning technologies, such like BART and BERT, are utilized for data analysis, humanities data still rely on traditional databases. Representative analysis methods include n-gram and lexical statistical extraction. However, when using a database, performance limitation is often imposed on the result calculations. This study presents an experimental process using MariaDB on a PC, which is easily accessible in a laboratory, to analyze the impact of the database on data analysis performance. The findings highlight the fact that the database becomes a bottleneck when analyzing large-scale text data, particularly over hundreds of thousands of records. To address this issue, a method was proposed to provide real-time humanities data analysis web services by leveraging the open source database, with a focus on the Seungjeongwon-Ilgy, one of the largest datasets in the humanities fields.

• Journal of Dental Anesthesia and Pain Medicine
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• 제24권3호
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• pp.205-211
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• 2024

A 7-year-old girl visited the Samsung Medical Center emergency room for primary tooth aspiration during primary tooth extraction under conscious sedation with N₂O. The patient showed no signs of respiratory complications. Chest radiography and CT revealed a tooth in the right bronchi. Foreign body removal using rigid bronchoscopy was performed on the day of aspiration. With close monitoring of the airway in the pediatric ICU, extubation was performed the next day, and the patient was discharged the same day. The primary objective of this case report was to highlight the potential risk of aspiration associated with the use of N₂O gas for conscious sedation.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.235-237
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• 2022

영상 콘텐츠는, 길이에 따라 롱폼 영상 콘텐츠와 숏폼 영상 콘텐츠로 구분된다. 롱폼 영상 콘텐츠는 15분 이상 길이로 생성되며, 편집 없이 촬영 영상의 모든 프레임들이 포함되도록 한다. 숏폼 영상 콘텐츠는 1분이상 15분 이내로, 촬영 영상의 프레임들로부터 일부 프레임만 짧은 길이로 편집할 수 있다. 최근 1인 방송 시장의 성장으로 인하여, 시청자들을 늘리기 위한 숏폼 영상 콘텐츠에 대한 수요가 확대되고 있다. 따라서, 숏폼 영상 콘텐츠를 편집하여 생성하는 콘텐츠 편집 기술에 대한 연구가 필요하다. 본 연구는 영상, 음성, 동작을 포착하여 주요 장면의 숏폼 동영상을 생성하는 기술을 연구한다. 주요 장면의 숏폼 동영상은 머신 러닝을 통해 미리 학습된 하이라이트 추출 모델을 이용한다. 하이라이트 영상을 자동으로 생성하는 영상 자동 편집 시스템 및 방법은 숏폼 영상 콘텐츠의 핵심 기술이다. 머신러닝 기반의 영상 자동 편집 방법 및 시스템 연구는 1인 크리에이터들의 영상 편집에 투입되는 노력과 비용시간을 감소시켜, 경쟁력있는 콘텐츠 활동을 할 수 있도록 기여할 것이다.

• Journal of the Korean Wood Science and Technology
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• 제50권2호
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• pp.113-125
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• 2022

This study aimed to explore the biodiversity of chemical compounds found in the bark of Guibourtia tessmannii from Gabon, commonly called Kévazingo, and evaluate their anti-termite activity to determine their potential values as a source of development of anti-termite products that can be valued in the fields of fine chemicals and wood preservation. Extraction of G. tessmannii bark powders was carried out using the cold maceration method with trichloroethylene, acetone, ethanol, and water. Phytochemical screening made it possible to highlight groups of chemical families present in the extracts. Anti-termite activity was tested on the wild termites "Cubitermes sp" of the genus Isoptera. The yield of the extracts were 17.11% for the buttress and 13.42% for the height at 6 m. Phytochemical tests revealed that alkaloids, polyphenols, sterols, tannins, reducing compounds, flavonoids, saponins, and anthraquinones were present in the extracts. Results of anti-termite activity indicated that anti-termite activity varied with the different parts of the bark studied, extraction solvent, and concentration (50/50) and (25/75) of the extracts used. The extracts at 50/50 concentration showed a slightly better anti-termite activity compared to the 25/75 concentration. In addition, the buttress Kévazingo or buttress showed the strongest anti-termite activity for the aqueous extract with a survival rate of 0% after 2 days.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권2호
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• pp.643-661
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• 2018

This paper proposes a novel algorithm for lane detection based on inverse perspective transformation and Kalman filter. A simple inverse perspective transformation method is presented to remove perspective effects and generate a top-view image. This method does not need to obtain the internal and external parameters of the camera. The Gaussian kernel function is used to convolute the image to highlight the lane lines, and then an iterative threshold method is used to segment the image. A searching method is applied in the top-view image obtained from the inverse perspective transformation to determine the lane points and their positions. Combining with feature voting mechanism, the detected lane points are fitted as a straight line. Kalman filter is then applied to optimize and track the lane lines and improve the detection robustness. The experimental results show that the proposed method works well in various road conditions and meet the real-time requirements.