Browsing by Author "Wang, DC"

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Accurate logic-level power simulation using glitch filtering and estimation
(1996)
Tsai, WC
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Shung, CB
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Wang, DC
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交大名義發表
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電子工程學系及電子研究所
Power estimation tool is needed to be more fast and accurate when the power consumption is the chief concern during the chip design. Logic-level simulator is a good choice to estimate the power consumption of a chip design. In this paper we attempt to improve the accuracy of a logic-level simulator using glitch filtering and estimation techniques. We use logic-level simulator to filter some glitches and estimate the glitch power. We use slope of transition and time interval of two consecutive transitions to decide whether these transitions is partial glitches or full transitions. We estimate the transition power of each transition event and summed them up. The power simulation error is reduced from 35.8% to 7.9% referring to the Spice simulation.
Instruction folding in Java processor
(1997)
Ton, LR
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Chang, LC
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Rao, MF
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Tseng, HM
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Shang, SS
Traditionally, the performance of a stack machine was limited by the true data dependency. A performance enhancement mechanism - Stack Operations Folding - was used in Srm Microelectronics' picoJava design [1][2] and it can reduce up to 60% of all stack operations. in this paper, we use the Java bytecode language as the targe; machine language, and study its instruction folding on a proposed machine model. Three folding strategies: 2-foldable, 3-foldable and 4-foldable, were simulated and evaluated. Statistical data show that our third folding strategy eliminates 73% of all stack operations, and each strategy fins an overall program speedup of 1.19, 1.25 and 1.26, respectively, as compared to a traditional stack machine. Moreover, a Java machine model suitable for instruction folding, together with its pipeline stages, are presented. lt seems to have the best cost/performance effectiveness of a Java stack machine if six bytes decoder width and the second folding strategy - the three-foldable strategy - are adopted.
Optical properties of high density InGaN QDs grown by MOCVD
(2006-07-01)
Lee, CK
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Hsu, JH
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Wang, DC
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Chang, YH
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Kuo, HC
In this article, we investigate the relaxation time constant and optical properties of InGaN QDs following different durations of SiNx treatment. We find that the smaller size QDs have smaller red shift as temperature increasing, only about 10 meV. Time-resolved PL at various emitting wavelength of the three samples is also investigated. Decreasing time constant as increasing QDs size is observed. Besides, we also find the decreasing time constant with shorter wavelength. Meanwhile, decreasing time constant as increasing emitting wavelength is characterized and attributed as an increasing confinement of excitons in QDs with higher localization energy and thus with a higher electron-hole overlap. (c) 2005 Elsevier B.V. All rights reserved.