Wireless body area networks (WBANs) are emerging as important networks, applicable in various fields. This paper surveys the WBANs that are designed for applications in healthcare. We present a comprehensive survey consisting of stand-alone sections focusing on important aspects of WBANs. We examine the following: monitoring and sensing, power efficient protocols, system architectures, routing and security. We conclude by discussing some open research issues, their potential solutions and future trends.

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A fundamental open question for oracles in blockchain environments is a determination of the amount of trust to be placed in the oracle. Oracles serve as intermediaries between a trusted blockchain environment and the untrusted external environment from where the oracles fetch data. As such, it is important to understand the uncertainty introduced by the oracle in the trusted blockchain environment and the implications of this uncertainty on blockchain performance. This paper develops a model for commoditization of trust. The model provides for dynamic trust environments that incorporates oracle selfishness. The work also considers the equilibrium behavior for the demand and supply for trust and introduces elastic incentives for increasing the trust. These results are used to determine optimum size of the network that can be served by an oracle with varying degrees of selfishness. Key consequences and challenges of incorporating oracles in trusted distributed ledger environments are presented.

Social networking sites have given users unprecedented opportunities for the generation and dissemination of content. A variety of social networking sites exist for different purposes, to afford users a range of anonymous and non-anonymous options for self-expression, and the ability to be a part of a virtual community. These “affordances” enable users to create and share content; however, the ability to partially or wholly detach user identity from the content has resulted in unique challenges for content access and content attribution. This paper proposes a framework for secure, trustworthy social networking that also creates value for user-generated content by using a blockchain-enhanced framework for social networking. This work explains the application of such a framework for collocated spaces of robots and IoT devices and identifies key challenges that result as a consequence of merging social networking sites and blockchain technology.

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Consensus algorithms are central to blockchain technology and an emerging research area. In this paper, we begin with an overview of the different types and architectures of blockchain networks. Then, with a focus on consortium blockchains, we survey, classify, and assess their principal consensus mechanisms. Furthermore, as consensus mechanisms determine network reliability, enhance performance efficiency, and ensure system security, we conduct a critical analysis of the strengths and weaknesses of consensus algorithms using a taxonomy of three different criteria: reliability, performance, and security. We conclude with insights into current and future research challenges and opportunities in this domain.INDEX TERMS Consensus, consortium blockchain, taxonomy.

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Abstract. Wireless body area networks (WBANs) are emerging as important networks, applicable in various fields. In this chapter a comprehensive survey of WBANs that are designed for applications in healthcare is presented. The survey consists of stand-alone sections focusing on important aspects of WBANs. Topics covered are: monitoring and sensing, power efficient protocols, physical layer, MAC protocols, routing, system architectures and security. The chapter concludes with a discussion of open research issues, their potential solutions and future trends.