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베이지안 알고리즘을 활용한 열차의 고장 예측 및 FRACAS 연동을 통한 예방 정비 방법
임종국(J. K. Lim),강명구(M. K. Kang),장건(G. Jang) 한국도시철도학회 2015 한국도시철도학회논문집 Vol.3 No.2
In order that complex system, such as train, is important to secure availability on service, reliability and maintainability on cost and safety, the efficient management method on those measures is necessary. According to the necessity, maintenance system which anticipate life-time of a train from failure data has been developed domestically. However, the method has limitation on aspect of preventive maintenance. For preventive maintenance, real-time analysis and prediction of train data are required, but train data is too much to handle in real time due to complexity of modern train system, so large amount of resources and considerable efforts are required to analyze. In order to overcome such difficulties, efficient method on handling the real time data is required. In this paper, Bayesian statistics is introduced to handle the huge amount of real time data efficiently. Bayesian statistics is utilized to generate a pattern of status information of a train. The pattern, then, is used to find out anomalous cases as failure symptom. In addition, the anomalous cases are transferred to FRACAS, FRACAS is possible to make maintenance instruction for those cases as means of effective preventive maintenance.
자기공명영상을 이용한 수삼의 내부 품질평가 및 연근판정
임종국,김철수,이승조,김성민 한국농업기계학회 2003 바이오시스템공학 Vol.28 No.2
The purpose of this study is to characterize the internal physical properties of fresh Korean ginsengs (Panax ginseng C.A. Meyer) through a magnetic resonance imaging (MRI) technique. Current external visual inspection cannot determine internal quality of ginsengs successfully. Relaxation time constants, T_1 and T_2, were obtained from a series of MR images. Calculated T_1 values were varied with different physiological states of ginseng tissues. Internal imaging information was obtained nondestructively from fresh ginsengs. One-and two-dimensional image analysis were performed. One-dimensional image analysis showed a potential of age identification of ginsengs rapidly. Internal quality of normal and abnormal ginsengs was evaluated using two-dimensional MR images. Various types of internal defects such as internal cavity and rotten spot were visualized clearly. The MRI technique had a feasibility to detect internal defects of fresh ginsengs effectively.
임종국,김성민 한국농업기계학회 2003 바이오시스템공학 Vol.28 No.3
In this study, the feasibility of magnetic resonance techniques for nondestructive internal quality evaluation of Korean red ginseng was examined. Relaxation time constants were measured using various grades of red ginsengs. Solid state magnetic resonance imaging technique was applied to image dried red ginseng which have low moisture contents (about 13%). A 7 tesla magnetic resonance imaging system operating at a proton resonant frequency of 300 MHZ was used for acquiring MR images of dried Korean red ginseng. The comparison test of cross cut digital images and magnetic resonance images of heaven grade, good grade with cavity inside, and good grade with white part inside red ginseng suggested the feasibility of the internal quality evaluation of Korean red ginsengs using MRI techniques. A good grade red ginseng included abnormal tissues such as cavities or white parts inside was observed by the signal intensity of MR image based on magnetic resonance properties of proton nucleus. Analysis on an one dimensional profile of acquired MR image of Korean red ginseng showed easy discrimination of normal and abnormal tissues. MR techniques suggested ways to detect internal defects of red ginsengs effectively.
주성분 분석을 이용한 홍삼의 내부품질과 자기공명특성 분석
임종국,김철수,김성민 한국농업기계학회 2003 바이오시스템공학 Vol.28 No.3
Ten MHZ pulsed NMR spectrometer was used to measure the magnetic resonance characteristics of Korean red ginseng. The difference in the internal structures of good and bad red ginseng was examined by their NMR characteristics. Average values of T_1 and free induction decay(FID) ratios of undergrade Korean red ginseng were the highest among the three groups categorized as normal, medium and under grades Korean red ginseng and average values of T_2 and T_2 of them were the lowest among the three groups. Principal component analysis(PCA) was used to observe the contribution of measured NMR values to the grade of Korean red ginseng. The measured T_1, T_2, T_3 and FID ratio of 79 Korean red ginsengs classified as normal grade, medium grade and under grade were examined using PCA analysis. Cumulative variance of PC1 through PC3 occupied more than 90% of total variance at first and second NMR measurement. Plots of PC scores for the most important PCs showed that normal red ginseng samples were distributed around the left region of PC1 axis and most of the undergrade red ginseng samples were scattered around the right region of PC1 axis.