초음파 비파괴 검사기법에 의한 용접결함 분류성능 비교

김재열,유신,김창현,송경석,양동조,김유홍 한국공작기계학회 2004 한국공작기계학회 추계학술대회논문집 Vol.2004 No.-

In this study, we made a comparative study of backpropagation neural network and probabilistic neural network and bayesian classifier and perceptron as shape recognition algorithm of welding flaws. For this purpose, variables are applied the same to four algorithms. Here, feature variable is composed of time domain signal itself and frequency domain signal itself. Through this process, we comfirmed advantages/disadvantages of four algorithms and identified application methods of four algorithms.

용접결함의 형상인식을 위한 분류기 알고리즘의 성능 비교

김재열,김영석,김창현,양동조,이창선,송경석 한국비파괴검사학회 2003 학술대회 논문집 Vol.- No.1

In this study, we compared backpropagation network(BPNN) with probabilistic neural network(PNN) as the classification algorithm of welding flaws. For this purpose variables are appied the same to two algorithm. Here, feature variable is composed of time signal itself and frequency signal itself. Those are ultrasonic signals reflected on welding flaws. Through this process, we comfirmed advantages/disadvantages of two algorithms, identified application methods of two algorithms to classification methods of welding flaws. These advantages/disadvantages and application methods are based on theoretical backgrounds.

초음파 검사 기반의 용접결함 분류성능 개선에 관한 연구

김재열,윤성운,김창현,송경석,양동조,--,-- 한국공작기계학회 2004 한국공작기계학회 춘계학술대회논문집 Vol.2004 No.-

In this study, we made a comparative study of backpropagation neural network and probabilistic neural network and bayesian classifier and perceptron as shape recognition algorithm of welding flaws. For this purpose, variables are applied the same to four algorithms. Here, feature variable is composed of time domain signal itself and frequency domain signal itself. Through this process, we comfirmed advantages/disadvantages of four algorithms and identified application methods of four algorithms.

P2P 네트워크에서 컨텐츠 분배가 가능한 멀티소스 미디어 스트리밍

소양선,최창열 강원대학교 정보통신연구소 2004 정보통신논문지 Vol.8 No.-

Recently, the Peer-to-Peer (P2P) contents sharing application is actively used in the Internet and as a result, concerns about P2P are more being increased. But because a file sharing scheme of existing P2P cannot play until media file is completely downloaded, there is a shortcoming that has long response time. The P2P media streaming which simultaneously can play as downloading media poses challenging problems compared with the file sharing approach. Especially, because each peer that constructs P2P network has different bandwidths, upload rates and computer capacities, in the media streaming that must receive media data within limited period, QoS is not sufficient in the case that peer receiving data acquires data from a certain peer. To solve for these problems, we can consider a multi-source streaming which receives data from various peers. In this paper, we describe multi-source media streaming system for the P2P network environment. In the proposed- scheme, firstly, we can increase a media transmission rate as receiving data from different peers. Secondly, after receiving media files, they can be played at the moment they are stored. Therefore we can reduce a user response time and distribute contents through networks. Thirdly, we can lead a fast contents distribution caused by transmission of a part of m d a file under downloading and concurrently can expect to increase the number of subscribers. We expect that the proposed multi-source media streaming system for the P2P network environment can be generalized for a high speed network as well as a b h capacity personal computer, so that it can deal with various multimedia contents.

세탁기용 자동변속기(Auto-Transmission)의 이상음 검사용 자동화 프로그램 개발

김재열,김양중,한재호,마상동,김창현 朝鮮大學校 機械技術硏究所 2000 機械技術硏究 Vol.3 No.1

This study includes automatic program for noise inspection of auto-transmission for washing machine one of modern home necessary. We effort to find and certificate sound noise source by sound power and sound intensity, and apply to frequency analysis in vibration related sound noise. Still more we have been studying to data acquisition and programming for MS VisualBasic version 5.0. System component is below. 1) Pentium PC for data acquisition. 2) DSO for noise acquisition. 3) S/W for comparison and decision. 4) I/F Board for data communication. Wave form data through the DSO are converting to ASCII code data. The ASCII code through binary converting S/W are to be decision fitness or the badness comparison S/W. Finally, we will making noise monitoring system and automatic program for inspection system

적외선 열화상 카메라를 이용한 열적 결함부 자동 검출 모니터링 시스템 개발

김재열,양동조,한재호,유신,김창현,송경석 한국비파괴검사학회 2004 학술대회 논문집 Vol.- No.-

The most part of various electrics has been affected by thermal failure due to electric overload. Contact-sensor has been used, for detection to this thermal failure, until now. But, it is impossible to detect the unsuitable element by using contact-temperature-sensor. This problem, with development of the infrared thermal vision camera, will be solved. Because it take some advantages which are composed of non-contact detect and non-destructive detect for temperature distribution, it is possible to detect on the temperature of revolution part, high temperature part. We developed the automatic detection monitoring system for thermal failure part on electrics with overload by using the infrared thermal vision camera. The first stage, thermal signal was detected from the infrared thermal vision camera, and then the data that was wanted from user was shown. The second stage, if the temperature that was decided to failure coded to the program, automatically electrics was shut off. This monitoring system is possible to apply on various conveniences in the whole industrial sites.

형상인식을 적용한 용접 결함의 특징변수 추출

김재열,마상동,오성민,송경석,김양중,김창현,곽이구 朝鮮大學校 機械技術硏究所 1999 機械技術硏究 Vol.2 No.2

In this study, the researches classifying the natural flaws in welding parts are performed using the signal pattern classification method. For this purpose 500MHz storage digital oscilloscope including FFT function and enveloped waveform generator are used and the signal pattern recognition procedure is made up the digital signal processing, feature extraction, feature selection and classifier design. Specially it is composed with and discussed using the distance classifier is based in euclidean distance the empirical Bayesian classifier. In feature extracting, it is performed using the class-mean scatter criteria. And the signal Pattern classification method is applied to the signal pattern recognition problems of natural flaw that is porosity inclusion, slag inclusion, lack of penetration, lack of fusion. center crack, side crack, toe crack. root crack as the planar and volumetric flaw classification problem. According to this results, if appropriately learned the neural network classifier is better acquire the recognition rate of 86.31% above through it is different a little according to domain extracting the feature and the classifier

3차원 레이저 진동측정기를 이용한 고속회전 모터의 진동특성 분석

김재열,김창현,송경석,양동조,곽이구,이창선 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

Noise cause is dividing to fluid noise by exhaust flow of fan and vibration noise by rotational vibration of motor. Until now, measuring method has been used to measure vibration by the accelerometer, this method has been not measured for the vibration in some parts of brush and commutator because of motor construction. This research was purposed on the accurate analysis, using laser vibration analyzer, of noise cause against the difficult part in old times. By using this measured data, we would like to use for the design of silent motor.

트랙타 부착 대형이앙기 개발 및 재배적 실용성

박성태,장익주,정창화,김상열,김재현,문헌팔,양세준,김순철 한국국제농업개발학회 2002 韓國國際農業開發學會誌 Vol.14 No.3

쌀 생산비를 줄이고 대경지 규모화 영농에 적응할 수 있는 농기계 개발을 목적으로 연구개발한 대규모 경지적응 트랙터 부착 대형벼이앙기의 구성과 특징 및 개발시작기의 재배적 실용성 평가결과를 요약정리하면 다음과 같다. 1. 트랙터 부착 12조 대형벼이앙기는 크게 바퀴자국 제거로타리, 문짝형 정지판, 이앙장치부 등으로 구성되어 있다. 2. 트랙터 부착 12조 이앙기는 트랙터 동력을 이용하여 로타리, 정지 및 이앙작업이 동시에 이루어 질 수 있도록 개발하였다. 3. 바퀴자국을 없애는 날은 기존의 로타리 날을 교체하면 되도록 반달형 날로 제작하였다. 4. 이앙기는 이동시는 접을 수 있도록 설계 제작되어 대형화가 가능하므로 기존 6조 승용이앙기에 비하여 이앙작업 능력이 1.5배 이상이었다. 5. 트랙터 부착 대형벼이앙기는 트랙터와 같은 큰 동력원을 이용할 수 있으므로 측조시비기, 긴매트모 탑재 등 다양한 작업기 및 기능을 추가로 부착 가능하도록 설계되었다. 6. 트랙터 부착 대형벼이앙기는 어린모 및 중묘이앙시 결주율은 3.0∼4.3%로 기계이앙기 결주 허용범위 5% 미만이었다. 하지만 무경운 논에서는 이앙작업은 가능하나 부묘율이 다소 높은 점은 보완이 필요하다. To develop a labor saving rice cultivation technology, a new tractor attached rice transplanter has been developed for large scale farming and its field performance was evaluated. The rice transplanter consists of three major parts such as rotary for removing tractor tire furrow, door-shaped soil leveling plate and transplanting equipment. The rice transplanter is operated using the power of the tractor and performs rotary, harrow and seedling transplanting simultaneously. A half moon shaped rotary blade was found to be very efficient to remove tire furrow developed during seedling transplanting and the original rotary blade can be replaced easily with existed rotary blade. The seedling transplanting part of the transplanter was designed to fold into small size and the transplanting efficiency of the transplanter was found to be 1.5 times higher than that of the conventional riding type six row transplanter. Since the transplanter is operated through a strong power of the tractor, the additional attachment such as fertilizer application apparatus and long mat rice seedling carrier is possible. Based on the field performance of the transplanter, although the missing hill percentage showed roughly with 3.0∼4.3% for 10-day and 30-day old seedlings but the percentage is less than 5% which is maximum missing hill permit in the transplanting rice. Seedling transplanting in no-tillage field condition is acceptable but floating seedling percentage is still high and thus further technology improvement for minimizing floating seedling percontage is needed.

(E)-5-hexadecenyl acetate: a novel moth sex pheromone component from Stathmopoda auriferella.

Yang, Chang Yeol,Choi, Kyung San,Cho, Myoung Rae [Plenum Pub. Corp.] 2013 Journal of chemical ecology Vol.39 No.4

<P>The sex pheromone of Stathmopoda auriferella (Walker), an important pest of kiwifruit in Korea, was studied. Two candidate pheromone components detected in the gland extracts of females were identified as (E)-5-hexadecenyl acetate (E5-16:OAc) and (E)-5-hexadecenol (E5-16:OH) in a ratio of 75:25 by mass spectral analysis of natural pheromone components and dimethyldisulfide adducts, and retention index comparisons with synthetic standards. In the kiwifruit orchards, E5-16:OAc alone was attractive to S. auriferella males and caught significantly more males than live virgin females. However, addition of E5-16:OH strongly inhibited attraction to E5-16:OAc. These results suggest that the major component of the female-produced sex pheromone of S. auriferella is E5-16:OAc. This hexadecenyl acetate is a novel moth sex pheromone component.</P>