No abstract

For a blockchain, consensus is the foundation protocol that enables cryptocurrencies such as Bitcoin to maintain state. Additionally, to ensure safety and liveness for a publicly accessible and verifiable ledger, fault tolerance must be robust. However, there appears to be a degree of misunderstanding about how consensus is applied across blockchains. To assist researchers considering variations between them, this study presents a rational classification of consensus methods applied to current blockchains. The study provides a survey of 19 methods classified by the scarce resource they employ: clock-cycles, bits, tokens, votes, time, and biometrics. Blockchain implementations are split between consensus algorithms requiring proof of resource and those that use majority voting to update the ledger.

This paper presents a method for a decentralised peer-to-peer software license validation system using cryptocurrency blockchain technology to ameliorate software piracy, and to provide a mechanism for software developers to protect copyrighted works. Protecting software copyright has been an issue since the late 1970's and software license validation has been a primary method employed in an attempt to minimise software piracy and protect software copyright. The method described creates an ecosystem in which the rights and privileges of participants are observed.

Big Data (BD) is a nascent term emerged to describe large amount of data that comes in different forms from various channels. In the modern world, users are the ceaseless generators of structured, semi-structured, and unstructured data that if gleaned and crunched precisely, will reveal game-changing patterns. While opportunities exist with BD, the unprecedented amount of data has brought traditional approaches to a bottleneck. The growth of data is outpacing technological and scientific advances in data analytics. According to multiple sources, it is estimated that 75% of the BD projects have failed within the last decade. Among the challenges, system development and data architecture are prominent. This paper aims to facilitate BD system development and architecture by conducting a systematic literature review on BD reference architectures (RAs). The primary goal is to highlight the state of BD RAs and how they can be helpful for BD system development. The secondary goal is to find all BD RAs, describe the challenges of creating these RAs, discuss the common architectural components of these RA and the limitations of these RA. As a result of this work, firstly major concepts about RA are discussed and their applicability to BD system development is depicted. Secondly, 22 BD reference architecture is assessed from academia and practice and their commonalities, challenges, and limitations are identified. The findings gained emerges the understanding that RAs can be an effective artefact to tackle complex BD system development.

The advance of technology often requires the emergence of complementary technologies, of which the transition from IPv4 to IPv6 presents a significant example. The move of protocol has focussed attention on the level of performance for associated technologies. Among the many Internet applications, in contemporary digital communications, VoIP stands apart in importance. This paper presents a performance analysis of VoIP using IPv4 and IPv6. Using OPNET to simulate the protocols and to investigate areas of performance weakness.