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The Dilemma of Parameterizing Propagation Time in Blockchain P2P Network
Sandi Rahmadika,노시완,이경모,Bruno Joachim Kweka,이경현 한국정보처리학회 2020 Journal of information processing systems Vol.16 No.3
Propagation time on permissionless blockchain plays a significant role in terms of stability and performance inthe decentralized systems. A large number of activities are disseminated to the whole nodes in the decentralizedpeer-to-peer network, thus causing propagation delay. The stability of the system is our concern in the firstplace. The propagation delay opens up opportunities for attackers to apply their protocol. Either by acceleratingor decelerating the propagation time directly without proper calculation, it brings numerous negative impactsto the entire blockchain system. In this paper, we thoroughly review and elaborate on several parameters relatedto the propagation time in such a system. We describe our findings in terms of data communication, transactionpropagation, and the possibility of an interference attack that caused an extra propagation time. Furthermore,we present the influence of block size, consensus, and blockchain scalability, including the relation ofparameters. In the last session, we remark several points associated with the propagation time and use cases toavoid dilemmas in the light of the experiments and literary works.
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Dos Santos A Silayo,M.C.T. Tarimo,Amini R.E. Kweka,Muganda A. Michael 한국외국어대학교 아프리카연구소 2006 Asian Journal of African Studies Vol.20 No.-
The Miombo woodlands in Bagamoyo district are among the richestplant community stands in Eastern Tanzania that is subjected to a serious human induced activities like of charcoal production, farming and grazing. We investigated on the ecological impacts of these activities on species diversity and composition. The study was conducted in Mbwewe general land forest and Uzigua forest reserve in Bagamoyo District, Coastal Region, Tanzania. These forests differ in both management and utilization regimes. We adopted a systematic sampling design for which, 48 sample plots; 30 plots in the public forest and 18 plots in the reserved forest were laid out for data collection. The number of plots for the general land forest was higher due its bigger size, vegetation heterogeneity and diverse human activities. About 81% tree and 19% shrubs of 59 different species were recorded. Acacia polyacantha sub species campylacantha and Brachystegia boehmiiwere dominant species in the general land and reserved forest respectively. Stand parameters; number of stems, basal area and wood volume per ha were higher in the reserved forest. Distribution of stem numbers by size class show reversed J-shape trend in both forest types, indicating active growth of the woodland while, wood volume and basal area per ha showed normal distribution. The Shannon - winner indexes of diversity were 2.86 and 2.5 while the indices of dominance were 0.08 and 0.11 indicating higher species diversity in the forest reserve. The loss of woodland species especially on the general land will continue with associated consequences if appropriate plant utilization and land use management practices are not carried out. We therefore recommend intensive law enforcement and community education. The government should also consider subsidizing electricity costs to make it 'affordable' so as to reduce high level of charcoal demand at the national level which was observed to be the main reason for tree cuts.
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