This book focuses on conducting a comprehensive analysis of blockchain scalability serving large-scale application scenarios, from the “what, why, how� three perspectives, layer by layer. Gathering the latest state-of-the-art research advances in the area of key issues and technologies for blockchain scalability, it also presents some special and exciting insights on the existing and future blockchain scalability. Despite blockchain’s merits of decentralization, immutability, non-repudiation, and traceability, the current blockchain has faced a serious scalability bottleneck. The scalability bottleneck problem is mainly manifested in two aspects: low-performance efficiency and difficulty in functional extension. First, the security and reliability of the blockchain system come from the fact that most nodes of the whole network participate in a distributed consensus to maintain the ledger. The high-cost consensus mechanism makes limited performance of blockchain, and there is a big gap between the actual large-scale application system. In addition, in order to ensure the security of a single blockchain system, data between different blockchain systems are relatively isolated, making it difficult for assets and data to interact. This book explores the scalability of blockchain in depth, proposes meaningful approaches to the problems mentioned above, and builds an original theoretical system of blockchain scalability. It describes the root of blockchain scalability problems, mainstream blockchain performance, the classification of existing scalability problem solutions, and some exciting sharding-based approaches. It also includes open issues and future directions to scale blockchain for complex practical application scenarios. As such, this book will be a valuable resource for students, researchers, engineers, and policymakers working in various areas related to blockchain scalability, which is also of great significance for understanding and solving the bottleneck of blockchain scalability and realizing the practical large-scale commercial application of blockchain.

The Metaverse seamlessly integrates the real world with the virtual world and allows avatars to engage in a broad range of activities including entertainment, social networking, and trading. In this book, we dive into the Metaverse by discussing how blockchains connect various Metaverse components, digital currencies, and blockchain-empowered applications in the virtual world. On the other hand, Web3 has also attracted considerable attention due to its uniquely decentralized characteristics. The digital economy, currently undergoing a rapid development, is a critical driver to highly efficient societies. It is imperative that we investigate how to use Web3 technologies to address the critical concerns encountered during the development of the digital economy by fully exploring Web3. In this book, we also share insights into the Web3-based ecosystem in the Metaverse; topics of interest include decentralized finance, digital assets, the asset-trading market, etc.  Unlike most works on the subject, this book mainly concentrates on insights and discussions regarding blockchain, the Metaverse and Web3. In other words, it focuses on using blockchain technologies to enable an ecosystem for both the Metaverse and Web3. Topics addressed include blockchain fundamentals, smart contracts, value circulation in the Metaverse, the connection between the Metaverse and Web3, the establishment of the Metaverse on the basis of blockchain technologies, decentralized autonomous organization, decentralized storage, digital economy, Web3-based economic systems for the Metaverse, etc. This book will be a valuable resource for students, researchers, engineers, and policymakers working in various areas related to blockchain, the Metaverse and Web3. We hope that it will also inspire readers from academia and industry alike, and ultimately help them create a truly open, fair, and rational ecosystem for the Metaverse and Web3.

This book constitutes the thoroughly refereed post conference papers of the Second International Conference on Blockchain and Trustworthy Systems, Blocksys 2020, held in Dali, China*, in August 2020. The 42 full papers and the 11 short papers were carefully reviewed and selected from 100 submissions. The papers are organized in topical sections: theories and algorithms for blockchain, performance optimization of blockchain, blockchain security and privacy, blockchain and cloud computing, blockchain and internet of things, blockchain and mobile edge computing, blockchain and smart contracts, blockchain and data mining, blockchain services and applications, trustworthy system development. *The conference was held virtually due to the COVID-19 pandemic.

This book constitutes the thoroughly refereed post conference papers of the First International Conference on Blockchain and Trustworthy Systems, Blocksys 2019, held in Guangzhou, China, in December 2019. The 50 regular papers and the 19 short papers were carefully reviewed and selected from 130 submissions. The papers are focus on Blockchain and trustworthy systems can be applied to many fields, such as financial services, social management and supply chain management.

Quality-of-Service (QoS) is normally used to describe the non-functional characteristics of Web services and as a criterion for evaluating different Web services. "QoS Management of Web Services" presents a new distributed QoS evaluation framework for these services. Moreover, three QoS prediction methods and two methods for creating fault-tolerant Web services are also proposed in this book. It not only provides the latest research results, but also presents an excellent overview of QoS management of Web sciences, making it a valuable resource for researchers and graduate students in service computing.

Zibin Zheng is an associate research fellow at the Shenzhen Research Institute, The Chinese University of Hong Kong, China. Professor Michael R. Lyu also works at the same institute.

Quality-of-Service (QoS) is normally used to describe the non-functional characteristics of Web services and as a criterion for evaluating different Web services. QoS Management of Web Services presents a new distributed QoS evaluation framework for these services. Moreover, three QoS prediction methods and two methods for creating fault-tolerant Web services are also proposed in this book. It not only provides the latest research results, but also presents an excellent overview of QoS management of Web sciences, making it a valuable resource for researchers and graduate students in service computing. Zibin Zheng is an associate research fellow at the Shenzhen Research Institute, The Chinese University of Hong Kong, China. Professor Michael R. Lyu also works at the same institute.

This book constitutes the proceedings of the 6th International Conference on the Internet of Vehicles, IOV 2019, which took place in Kaohsiung, Taiwan, in November 2019. The 23 papers presented in this volume were carefully reviewed and selected from 101 submissions. The papers focus on providing new efficient solutions with digital intervehicular data transfer and overall communications. Yet, IOV is different from Telematics, Vehicle Ad hoc Networks, and Intelligent Transportation, in which vehicles like phones can run within the whole network, and obtain various services by swarm intelligent computing with people, vehicles, and environments.