Browsing by Author "Wei, TH"

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An automated IP synthesizer for limited-resource DWT processor
(2002)
Wei, TH
;
Huang, SR
;
Dung, LR
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This paper presents a systematic design methodology for 1-D/2-D DWT processor based on a novel limited-resource scheduling algorithm. Given a set of architecture constraints and DWT parameters, the scheduling algorithm can generate four scheduling matrices that drive the data path to perform the DWT computation. Based on the limited-resource scheduling algorithm an automated DWT processor synthesizer has been developed and generates constrained DWT processors in the form of silicon intelligent property (SIP). The DWT SIP can be embedded into a SOC or mapped to program codes for commercial off-the-shelf (COTS) DSP processors with programmable devices. As a result, it has been successfully proven that a variety of DWT SIPs can be efficiently realized by tuning the parameters and applied for signal processing applications.
Signs of nonlinear refraction in chloroaluminum phthalocyanine solution
(1998-05-18)
Wei, TH
;
Huang, TH
;
Lin, MS
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應用化學系
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Department of Applied Chemistry
Opposite signs of nonlinear refraction in chloroaluminum (ClAl) phthalocyanine (Pc) dissolved in methanol are observed using the Z-scan technique with two output modes of a frequency-doubled, Q-switched, mode-locked Nd:YAG laser operating at 10 Hz. Using the single picosecond (ps) pulses switched out of the pulse trains, positive nonlinear refraction is observed and attributed to population transitions among ClAlPc's singlet states. Using the full nanosecond pulse trains, a sign change of nonlinear refraction relative to that of single ps-pulse excitation is observed, and is attributed to the heat-induced temperature rise and the population relaxing to CLAlPc's triplet states. (C) 1998 American Institute of Physics. [S0003-6951(98)01720-3].
Studies of nonlinear absorption and refraction in C-60/toluene solution
(2000-02-18)
Wei, TH
;
Huang, TH
;
Wu, TT
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Tsai, PC
;
Lin, MS
Nonlinear absorptive and refractive properties of C-60/toluene solution are studied using the Z-scan technique and a 532 nm laser delivering single picosecond (ps) pulses and trains of ps pulses separated by 7 nanoseconds (ns). With single ps pulses, reverse saturable absorption and positive nonlinear refraction are observed and attributed to population transitions among the singlet states. With ps pulse trains, a sign change of nonlinear refraction relative to that of single ps-pulse excitation is observed and is attributed to heat-induced temperature rise and population relaxing to triplet states. (C) 2000 Elsevier Science B.V. All rights reserved.
Sum frequency vibrational spectroscopy of the liquid-air interface of aqueous solutions of ethanol in the OH region
(2001-06-01)
Ju, SS
;
Wu, TD
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Yeh, YL
;
Wei, TH
;
Huang, JY
The surface vibrational spectroscopy of ethanol (C2H5OH, ethyl alcohol): water binary mixture, or the aqueous solution of ethanol, is investigated via sum frequency generation (SFG) in the OH region (3000 to 3900 cm(-1)). The bulk molar ratio of the ethanol is varied from x = 0.0024 to 0.20. Our concentration dependence results support the statement that the surface density of water molecules with a free dangling OH bond is about 25% in the air/water interface. It also indicates that the ethyl group of the surface ethanol molecules sticks out above the nominal surface, while the hydroxyl group alone is immersed in the mixture solution. And the surface layer is a mixed monolayer. We have demonstrated here that a LiNbO3 Crystal containing -OH can be sufficient for the SFG spectroscopy measurement in the -OH region regardless of its absorption dip.