• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.124-132
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• 2018

This research presents the results of an investigation on the characteristic of multi-component blended high fluidity mortars. The binder was blended ordinary Portland cement(OPC), ground granulated blast furnace slag(GGBFS), calcium sulfoaluminate(CSA) and ultra rapid setting cement(URSC). The GGBFS was replaced by OPC from 30%(P7 series), 50%(P5 series) and 70%(P3 series), CSA and URSC was 10% or 20% mass. The superplasticizer of polycarboxylate type were used. A constant water-to-binder ratio(w/b)=0.35 was used for all mixtures. Test were conducted for mini slump, setting time, V-funnel, compressive strength and drying shrinkage. According to the experimental results, the contents of superplasticizer, V-funnel and compressive strength increases with an increase in CSA or URSC contents for all mixtures. Moreover, the setting time and drying shrinkage ratio decrease with and increase in CSA or URSC. CSA decreased dry shrinkage but URSC had less effect. However, the mixed binders of CSA and URSC had a large effect of reducing drying shrinkage by complementary effect. This is effective for improving the initial strength of URSC, and CSA is effective for the expansion and improvement of long-term strength.

• The Journal of Society for e-Business Studies
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• v.18 no.3
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• pp.107-123
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• 2013

In a wireless sensor network environment, it is required to ensure anonymity by keeping sensor nodes' identifiers not being revealed and to support real-time authentication, lightweight authentication and synchronization. In particular, there exist possibilities of location information leakage by others, privacy interference and security vulnerability when it comes to wireless telecommunications. Anonymity has been an importance issue in wired and wireless network environment, so that it has been studied in wide range. The sensor nodes are interconnected among them based on wireless network. In terms of the sensor node, the researchers have been emphasizing on its calculating performance limit, storage device limit, and smaller power source. To improve of biometric-based D. He scheme, this study proposes a real-time authentication protocol using Unique Random Sequence Code(URSC) and variable identifier for enhancing network performance and retaining anonymity provision.