Browsing by Author "Cheng, RH"

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Negative differential resistance in InGaAs/AlAsSb/InGaAs single-barrier heterostructure
(1997-09-08)
Chen, WK
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Cheng, RH
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Ou, J
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交大名義發表
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電子物理學系
We have observed negative differential resistance in InP lattice-matched InGaAs/AlAsSb/InGaAs single-barrier tunneling heterostructure. With a 10-nm-thick barrier, the diode exhibits a peak-to-valley current ratio of 4.2 (1.2) and peak current density of 54 (158) A/cm(2) at 100 K(300 K). (C) 1997 American Institute of Physics.
Recognition of radicals in handwritten Chinese characters by means of problem reduction and knowledge guidance
(1996-09-01)
Cheng, RH
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Lee, CW
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Chen, Z
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資訊工程學系
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Department of Computer Science
Recognizing handwritten Chinese characters is a complex problem. We break the problem down into a series of sub-problems and concentrate on the radical recognition problem. The sub-problems are linked in a hierarchy of three layers: radical, radical sub-unit, and salient stroke. This problem reduction technique enables us to solve complex recognition problems effectively. We describe how to analyze and choose radical sub-units and salient strokes in order to recognize a set of radicals. We also construct two knowledge bases in the form of decision trees to guide the hypothesis and test procedures used to solve the recognition sub-problems. The problem reduction is done in a top-down fashion, while the problem solving process proceeds in a bottom-up fashion. The advantages of our method are described. The representation and organization of the two knowledge bases are explicitly described. The method is tested on two sets of handprinted characters using an TBM PC (486-33). The recognition rate is over 95.7% and the computer time needed to recognize a radical averages about 0.07 s. The experimental results indicate that our method effectively copes with a wide range of ordinary variations encountered in handwritten Chinese characters.