Browsing by Author "Lai, JH"

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Application of fuzzy control to a road tunnel ventilation system
(1998-11-16)
Chen, PH
;
Lai, JH
;
Lin, CT
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper deals with the serious problems of ventilation system in a large road tunnel. Higher visibility and lower concentration of carbon monoxide are the key issues concerning the ventilation system. Prior to designing the fuzzy control model, a configuration layout of the ventilation system including sensing, control and traffic prediction as well is conceptually constructed. Based on the layout that offers assignments of sensors and control elements, a fuzzy logic control model is developed. Membership functions of sensor errors and control increments are physically submitted in order to set up the fuzzy logic rules. Timing and spacing filtering in terms of weighting approaches is employed in the fuzzy logic rules. A dynamic equation describing the concentration of air pollution is also given so as to cooperate with the fuzzy logic rules and to play roles in the computer simulation. The result of computer simulation involving five cases indicates that a multi-level scheme is able to solve the engineering problems. (C) 1998 Elsevier Science B.V. All rights reserved.
Application of fuzzy control to a road tunnel ventilation system
(1998-11-16)
Chen, PH
;
Lai, JH
;
Lin, CT
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper deals with the serious problems of ventilation system in a large road tunnel. Higher visibility and lower concentration of carbon monoxide are the key issues concerning the ventilation system. Prior to designing the fuzzy control model, a configuration layout of the ventilation system including sensing, control and traffic prediction as well is conceptually constructed. Based on the layout that offers assignments of sensors and control elements, a fuzzy logic control model is developed. Membership functions of sensor errors and control increments are physically submitted in order to set up the fuzzy logic rules. Timing and spacing filtering in terms of weighting approaches is employed in the fuzzy logic rules. A dynamic equation describing the concentration of air pollution is also given so as to cooperate with the fuzzy logic rules and to play roles in the computer simulation. The result of computer simulation involving five cases indicates that a multi-level scheme is able to solve the engineering problems. (C) 1998 Elsevier Science B.V. All rights reserved.
Application of neural fuzzy network to pyrometer correction and temperature control in rapid thermal processing
(1999-04-01)
Lai, JH
;
Lin, CT
;
電控工程研究所
;
Institute of Electrical and Control Engineering
Temperature measurement and control are two difficult problems in the rapid thermal processing (RTP) system. For many applications such as rapid thermal processing chemical vapor deposition (RTCVD) [1] and rapid thermal oxidation (RTO) [2], large changes in wafer emissivity can occur during film growing, leading to erroneous temperature measurements with a single wavelength pyrometer. The error in the inferred temperature will affect the temperature control of the RTP system. In order to correct the temperature reading of the pyrometer, a neural fuzzy network is used to predict the emissivity changes for the compensation of measured temperature. As for the temperature control, to overcome ill performance of the temperature tracking system due to the inaccuracy of the identified model, another neural fuzzy network is used in the RTP system for learning inverse control simultaneously. The key advantage of neural fuzzy approach over traditional ones lies on that the approach does not require a mathematical description of the system while performing pyrometer correction and temperature control. Simulation results show that the adopted neural fuzzy networks can not only correct the pyrometer reading accurately, but also be able to track a temperature trajectory very well.
Influence of annealing sequence on p(+)/n junction images studied by scanning capacitance microscopy
(2004)
Chang, MN
;
Wan, WW
;
Chen, CY
;
Lai, JH
;
Liang, JH
We have successfully employed scanning capacitance microscopy (SCM) operated under low photoperturbation to investigate electrical junction profiles in low-energy BF2+-implanted silicon wafers treated by various annealing sequences. Differential capacitance images reveal that rapid thermal annealing (RTA) followed by furnace annealing (FA) treatments (RTA+FA) can result in a narrower junction width and a shallower electrical junction depth than FA followed by RTA treatments (FA+RTA). Experimental results also indicate that the wider junction of the FA+RTA treated sample is due to the shallower concentrated distribution of electrically activated boron atoms upon annealing. Subtle correlations between electrical junctions and annealing conditions are discussed. (C) 2004 The Electrochemical Society.