광 검출기를 이용한 플라즈마 감시장치에 대한 연구

장영건 청주대학교 산업과학연구소 1998 産業科學硏究 Vol.16 No.-

Plasma monitoring system which detect plasma signals and store them for Laser welding quality evaluation and analysis using photo detector is presented. The most fundamental and important aspects in such a system are signal restoration fidelity, noise immunity and noise cancelation capability. In this paper, 1 propose a implementation method using distnbute processing structure and hybrid digital communication for high noise cancelation capability, immunity and signal fidelity which are poorly presented in other researches. Lab experimental results and welding experimental results show a effectiveness of proposed method and plasma data is stored with 255 kbps without any communication error.

레이져 용접의 결함을 인식하기 위한 특징벡터 추출에 관한 연구

장영건,조경환 청주대학교 산업과학연구소 2000 産業科學硏究 Vol.17 No.2

An online plasma monitoring system which detects plasma signals and recognizes welding defects by analyzing the signals using photo detector is developed. To recognize welding defects effectively and reliably, one of the most important things is feature extraction. In this paper, various time domain and frequency domain features for welding defect recognition are introduced, compared and analyzed considering target seperability, real time capability, memory reduction and noise effect compression. Simulation results and welding experimental results show maximum and corresponding relative signal intensity of histogram without nomalization is the best feature among zero crossing rate, IAV, PSD, LPC and other histogram features. Using the feature, correct recognition rate is over 92% with robustness, minimum memory usage and simple recognition method.

시간지연을 갖는 쌍전파 신경회로망

장영건 청주대학교 산업과학연구소 1996 産業科學硏究 Vol.14 No.-

A new neural network model, time delayed counterpropagation neural network(TDCPN) which has higher recognition rate but lower learning time, is proposed. The model has the time-delay arrangement of time delayed neural network(TDNN) and the learning method of Counter-propagation network(CPN). The performance of a proposed model in the recognition of numerical speechs uttered by specific speaker is tested. Experimental results show that the recognition rate of the model is better than CPN, the learning time is shorter than TDNN. But this model needs a lot of memory 40 times more than TDNN for high recognition.

단일구동모터형 무인운반차 제어장치에 관한 연구

장영건 청주대학교 산업과학연구소 2000 産業科學硏究 Vol.18 No.1

Automated guided vehicle systems (AGVS) are widely used for transporting material in manufacturing and warehousing applications. These systems offer many advantages over other forms of material transport. However, the design of these systems is complex due to the interrelated decisions that must be made and the large number of system design alternatives that are available. In particular, the design of the AGVS control system for one traction motor type can be quite challenging, and it can dramatically reduce the system cost and increase the performance. In this paper, an AGVS control system design is presented using traditional 2 traction motor type controller and new additional controller. It is convenient and simple for manufacturing and maintenance as well as maintaing advantages of one traction motor type controller.

임베디드 XP기반의 지능형 원격감시제어 시스템 개발

장영건,최훈일 청주대학교 산업과학연구소 2007 産業科學硏究 Vol.24 No.2

Although the wire & wireless remote monitoring & control technology enters in mature stage, most of system houses which supply monitoring & control system use specific communication devices, do not have various communication resources in the area with low population density area such as rural community or mountain regions. In this study, we develops the intelligent remote monitoring & control system which use embedded XP board and CDMA modem. In korea, there is rare shadow region on cellular phone, this system can be used well in the low population densely region.

난독증자의 전자문서 접근을 위한 보조기술 연구

장영건 청주대학교 산업과학연구소 2006 産業科學硏究 Vol.24 No.1

Dyslexia, learning disability can be medicated or overcome by using proper assertive devices. The dyslexics suffer from insufficient color contrast of electronic documents and mangle deficit of brain to access them. In this study, a clinical test for the algorithm of ARRT and WCAG 2.0 is performed to evaluate the effectiveness of the algorithm and threshold values. A new algorithm considering color temperature feeling is presented for dyslexics and S/W color filters are developed for those of Ireland syndrome. The results of the test show that each algorithm of WK has a different superiority and defect over each other, is not perfect and the suggested algorithm is superior to others with respect to linearity between color contrast and readability.

가상 색 오버레이의 모바일 플랫폼 구현에 관한 연구

장영건 청주대학교 2013 産業科學硏究 Vol.30 No.2

A film colored overlay has been used as an assistive device for dyslexics, Recently, several virtual colored overlays which can be used in computer were developed. But mobile virtual overlay has not been developed yet. In this paper, I implemented a mobile overlay application which is based android operating system and displays a colored overlay of screen all the time while user can freely interact with rest of apps in normal manner by using root window and foreground service. A method is presented to determine the source color of a virtual overlays by estimating alpha value of alpha blending algorithm through measurement of the chromaticity and transmissivity of film overlays and I implemented all colors which are presented by using Intuitive Overlays. Test results of the developed virtual overlay show that all colors of the overlays are almost identical to the colors of Intuitive Overlays.

U-헬스케어 시스템 구현에 관한 연구

장영건 청주대학교 2008 産業科學硏究 Vol.25 No.2

This study introduces the meaning of ubiquitous which incorporates some of technologies as like measurement of bio signal, analysis, says to develop wireless communication module "Zigbee" and make realized "Sensor Network Systems" using it. I developed a stomach type band which is mainly for emergency situation, and can monitor breath, pulse, temperature and movement, tested its performances. The average temperature error was 0.18C and maximum error was 0.3C. Pulse by simulator showed error between ± 3bpm/min and the breathing rate error was 0%. Also noted that the measurement for signal count, it is automatically changed according to movement. This study says that new improved model of medical service come truth along with new paradigm "u-Healthcare" and it will make possible to check & manage their health, support optimum conditions and finally improve their life quality.

주변 조명에 따른 가상 색 오버레이의 색도변화

장영건 청주대학교 2013 産業科學硏究 Vol.31 No.1

A film colored overlay has been used as an assistive device for dyslexics. Recently, several virtual colored overlays which can be used in computer were developed. But mobile virtual overlay has not been developed yet. In this paper, I implemented a mobile overlay application which is based android operating system and displays a colored overlay of screen all the time while user can freely interact with rest of apps in normal manner by using root window and foreground service. A method is presented to determine the source color of a virtual overlays by estimating alpha value of alpha blending algorithm through measurement of the chromaticity and transmissivity of film overlays and I implemented all colors which are presented by using Intuitive Overlays. Test results of the developed virtual overlay show that all colors of the overlays are almost identical to the colors of Intuitive Overlays.

레이저 용접결함의 지능적 인식기법에 관한 연구

장영건 청주대학교 산업과학연구소 1999 産業科學硏究 Vol.17 No.1

An online plasma monitoring system which detect plasma signals and welding defects by analyzing the signals using photo detector is developed. In this paper, intelligent recognition method for welding defect is proposed using histogram as welding feature. To recognize welding defects effectively and reliably, one of the most impotant aspect is feature selection. Histogram of plasma signal intensity represent both of statistic and dynamic informations of the signals. Lab experimental results and welding experimental results show effectiveness of proposed method and correct welding defect recognition rate is 98.43%, 100% respectively using perceptron and fuzzy logic for 0.5 sec data, we import the welding defect recognition algorithm on a DSP board in the system.