1,721,000 research outputs found
Consolidation algorithm based on adaptive dynamic threshold for point-to-multipoint connections in ATM networks
No full textThe major concern at a branch point in asynchronous transfer mode (ATM) networks for point-to-multipoint available bit rate (ABR) services is how to consolidate backward resource management (BRM) cells from each branch for a multicast connection. In this paper. we propose an efficient feedback consolidation algorithm based on an adaptive dynamic threshold (ADT) to eliminate consolidation noise and to reduce consolidation delay. The main idea of the ADT algorithm is that each branch point estimates the ABR traffic condition of the network through virtual queue estimation. Simulation results show that the proposed ADT algorithm can achieve a faster response in congestion status and a higher link utilization compared with the previous works
End-to-End rate-based congestion control using EWMA for multicasting in IP based networks
No full textA New Consolidation Algorithm in Point-To-Multipoint ABR Service of ATM Networks for Industrial Applications
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Rupture time analyses of the Sn-3.5Ag solder alloys containing Cu or Bi
No full textThe creep rupture properties of Sn-3.5Ag based ternary alloys with varying amounts of Cu or Bi were investigated using rolled and heat-treated bulk specimens. Nominal compositions of the third element were 0% (Base), 0.5, 0.75, 1.0 and 1.5% Cu and 2.5, 4.8, 7.5 and 10% wt% Bi, respectively. The alloys generally showed the secondary and tertiary creep characteristics only, and the minimum strain rates (<(&epsilon;)over dot>(min)) were lowest for the 0.75 Cu specimens, and highest for the 10 Bi specimens. The stress exponents (n) Of <(&epsilon;)over dot>min were usually around 4 +/- 1, with the exception of the 0.5 Cu and 0.75 Cu alloys with n = 6.0similar to7.6, and the 10 Bi alloy which showed n similar to 2. Fractographic analyses revealed typical creep rupture by the nucleation and growth of cavities in the matrix for the Base and Cu-containing alloy except the 1.5 Cu specimens, which showed cavity nucleation by the cracking of brittle Cu6Sn5 particles. On the other hand, all the Bi-containing alloys showed cavity nucleation on grain boundaries due to the segregation of Bi to the beta-Sn grain boundaries. Subsequent rupture time analyses showed that creep rupture by necking could predict rupture times of the Base and the Cu-containing alloys reasonably, and that the model based on the continual nucleation of cavitating facets could explain the rupture times of the Bi-containing alloys reasonably well. The Kachanov equation made reasonable predictions of the rupture time for all cases. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved
Application of the Modified One-Sided Stress Wave Velocity Measurement Technique for Curing Monitoring of Early-Age Concrete
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Improved Rayleigh wave velocity measurement for nondestructive early-age concrete monitoring
No full textA modified one-sided technique is proposed for Rayleigh wave ( R-wave) velocity measurement in concrete. Wave scattering from material heterogeneity and near-field effects may disrupt sensed R-wave signals in concrete, which is manifested as signal dispersion. Conventional one-sided measurement techniques for concrete do not consider dispersion of R-waves. In this study, the maximum energy arrival concept is adopted to determine the wave velocity by employing continuous wavelet transform. Experimental and numerical studies are performed to show the effectiveness of the proposed method. The method is applied to monitor the strength development of early-age concrete exposed to various curing conditions. Results reveal that the proposed method can be effectively used to measure the R-wave velocity in concrete structures and further to monitor the development of compressive strength in early-age concrete, regardless of the concrete moist curing condition.This work was supported by both a research project of the Ministry of
Construction and Transportation (Grant No. 05CORETECH-C19) and an
engineering research center (ERC), Smart Infrastructure Technology Research
Center (SISTeC), program of Korea Science and Engineering Foundation
(Grant No. R11-2002-101-03001-0). Thanks go to Jin-Keun Kim at KAIST
and Won-Joon Song at RIST for their valuable discussions on the results,
and Jeong-Su Kim and Ji-Young Min, both at KAIST, for their help preparing
the experiments.
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