The Blockchain has been given great attention in recent literature among emerging technologies in software architectures. More specifically, when verifiable transactions between untrusted parties are concerned in a safe and reliable environment, its peculiar decentralized and tamper-proof structure makes it suitable for a vast class of business domains, such as Cloud Manufacturing, which is a new paradigm in the industry based on cloud technologies. However, the stiffness of existing solutions, that are unable to provide and implement heterogeneous services in a Cloud environment, emphasizes the need of a standard framework to overcome this limit and improve collaboration. Firstly, this paper introduces a Blockchain based platform designed with Smart Contracts for improving digital processes in a manufacturing environment. The primary contribution is the integration of two popular cloud technologies within the Blockchain: Docker, a scalable platform to run applications in lightweight environments, and Cloud Storage. Each process available in the platform requires input files and produces output files by using cloud storage as a repository and it is delivered by the owner as a self-contained Docker image, whose digest is safely stored in the chain. Secondly, with the purpose of selecting the fastest node for each new process instance required by consumers, we introduce a task assignment problem based on a deep learning approach and past metrics. The proposed platform is applied to a real-world industrial case study regarding ophthalmic lenses manufacturing and the optimization of lens surface calculation.INDEX TERMS Cloud manufacturing, blockchains, software architecture, distributed ledger, smart contracts, computer architecture.
I. INTRODUCTIONCloud Computing significantly changed the way industries do their business today [1]. In 2020, enterprise spending on cloud infrastructure services amounted to almost 130 billion U.S. dollars, while in 2011 it was only 3.5 [2]. In manufacturing industry, the adoption of cloud technologies lead to the new paradigm of Cloud Manufacturing [3], which enables companies to provide and receive services over Internet via an intelligent service-oriented architecture.The associate editor coordinating the review of this manuscript and approving it for publication was Nitin Gupta .Decentralization is a key factor both in Cloud Computing and Cloud Manufacturing as distributed architectures improve services reliability, scalability and performance when compared to traditional on-premise centralized approaches [3]. Similarly, security is also a key concern in these contexts as data elaborated in the cloud may be compromised, altered or stolen and the integrity of services could be severely affected [4].Blockchain, as a secure ledger for storing transactions, plays a strategic role in modern distributed architectures and the recent literature has shown a great interest about this revolutionary technology over the last decade. A systematic review provided in [5], shows that Blockchain based
