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Browsing by Author "Liao, HY"

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    An efficient TCP flow control and fast recovery scheme for lossy networks
    (2001)
    Liao, HY
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    Chen, YC
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    Lee, CL
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    資訊工程學系
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    Department of Computer Science
    The initial TCP Tahoe version uses the slow-start algorithm to deal with flow control and congestion avoidance. The later Reno version deploys both fast-retransmit and fast-recovery algorithms, Traditionally a segment loss is considered as owing to the network congestion. However, a packet loss may be caused by some other reason such as a transmission error in the wireless link. Due to this reason, we design a mechanism that subdivides the congestion control mechanism into two parts, the packet loss indication and the loss recovery. Regarding the former, we no longer treat the packet loss caused by the transmission error as an indication of network congestion. While for the latter, we proposed a modified scoreboard algorithm in TCP FACK to quickly recover the packet loss and prevent the retransmitted packet from being lost again.
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    Density functional study of the relative reactivity in the concerted 1,3-dipolar cycloaddition of nitrile ylide to disubstituted ethylenes
    (2001-07-05)
    Liao, HY
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    Su, MD
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    Chung, WS
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    Chu, SY
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    應用化學系
    Density functional theory was used to perform a theoretical evaluation of (E)-1,2-disubstituted ethylenes as dipolarophiles for the 1,3-dipolar cycloaddition reaction. The reactivities of electron-withdrawing and -donating substituted ethylenes were examined by estimating their activation energies. The calculated activation energies predicted that the most reactive species is (E)-1,2-C2H2(NO)(2), whereas the least reactive is (E)-2-butene. Namely, it was demonstrated that 16-electron 1,3-dipole reactants with more electropositive substituents in terminal positions and ethylenes that possess more strongly electron-withdrawing substituents facilitate 1,3-dipolar cycloaddition reactions. All of the theoretical results can be rationalized using the configuration mixing model. (C) 2001 John Wiley & Sons, Inc.