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Kang, S.H.;Park, Y.G.;Kwon, S.S.;Shin, T.S.;Lim, K.J.
- Journal of the Korean Society of Safety
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- v.14 no.1
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- pp.216-221
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- 1999
The correlation between propagation of electrical tree and internal partial discharges is discussed. We use specimens with needle-plane electrode system made of LDPE(Low Density Polyethylene), observed inception and propagation of electrical tree by optical microscope and investigated the characteristics of the partial discharge (PD) pulses accompanying with propagation of electrical tree. In the specimens with needle-shaped void, the tree propagates branch type. The length of the tree has good linear relation with average discharge power of PD pulses. In the specimens without needle-shaped void, the tree grows bush type tree. The correlation between the area of the tree and the average discharge power of PD pulses has linear relation.
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Bae, Misook;Hwang, Buhyun
- Proceedings of the IEEK Conference
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- 2002.07c
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- pp.1859-1862
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- 2002
The replication of data is used to increase its availability, improve the performance of a system, and advance the fault-tolerance of a system. In this paper, it is required for the information about the location of a primary site of the replicas of each data item. The replicas of each data item are hierarchically organized to a tree based on the fact that the root is the primary replica in partially replicated databases. It eliminates useless propagation since the propagation can be done to only sites having replicas following the hierarchy of data. And our algorithm schedules transactions so that the execution order of updates at each primary site is identical at all sites by using timestamp. Using our algorithm, the consistent data are supplied and the performance of read-only transactions can be improved by using tree structure of replicas of each data item.
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