• 산업공학
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• 제20권3호
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• pp.288-297
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• 2007

Success of semiconductor/LCD industry depends on its yield and quality of product. For the purpose, FDC (Fault Detection and Classification) system is used to diagnose fault state in main manufacturing processes by monitoring time series data collected by equipment sensors which represent various conditions of the equipment. The data set is segmented at the start and end of each product lot processing by a trigger event module. However, in practice, segmented sensor data usually have the features of data asynchronization such as different start points, end points, and data lengths. Due to the asynchronization problem, false alarm (type I error) and missed alarm (type II error) occur frequently. In this paper, we propose a robust process fault detection system by integrating a process event detection method and a similarity measuring method based on dynamic time warping algorithm. An experiment shows that the proposed system is able to recognize abnormal condition correctly under the asynchronous data situation.

• 기술혁신학회지
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• 제5권2호
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• pp.129-140
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• 2002

This study is try to do the empirical tests on the relationship among innovation cycle, investment cycle, and business cycle suggested in recent economic growth models. We apply co-spectra analysis to estimate dynamic correlations in the extraction HP filtered variables and first difference filtered variables in our data set. Our empirical results are; (i) an existing asynchronization between innovation cycle and investment cycle, (ii) in the long frequency, an existing positive correlation between innovation cycle and business cycle, (iii) in the short frequency, however, a finding the high negative correlation between the two cycle. Our empirical findings support the recent growth through cycle models and suggest some economic policy implementations for economic stabilization during a severe business cycle.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.58-58
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• 2000

As many sensors and actuators are used in various automated systems, the application of network system to real-time distributed control is gaining acceptance in many industries. In order to take advantages of the network technique. however, network implementation should be carefully designed to satisfy real-time constraints and to consider network delays. This paper presents the implementation of feedback control system in Profibus-DP. Profibus-DP is a type of fieldbus protocols that are specifically designed to interconnect simple devices with fast I/O data exchange. As feedback control in profibus-DP is implemented, Network delays is found with influence of system performance. We analyze network delays in Profibus-DP into 3 reasons - dead time in Profibus interface, protocol delay, delay by asynchronization. In order to compensate the network delays, we introduce control algorithms with time delay concept. The results show that network delay can be compensated.