Blockchain-Research and Applications最新文献

Recommendation systems provide ease and convenience for users to address information overload problems while interacting with online platforms such as social media and e-commerce. However, it raises several questions about privacy, especially for users who prefer to remain anonymous, especially on online social networks (OSNs). Moreover, due to the commercialization of online users' data, some service providers sell users' data to third parties at the blind side of the users, which leads to trust issues between users and service providers. Such matters call for a system that gives online users much-needed control and autonomy of their data. With the advancement of blockchain technology, many research institutions are experimenting with decentralized technologies to resolve the OSN user dilemma of privacy intrusion against third parties and hacks. To resolve these limitations, we propose RecGuard, a privacy preservation blockchain-based network system. We developed two smart contracts, RG-SH and RG-ST, to ensure the security and privacy of user data. The RG-SH manages user data, whereas the RG-ST stores data. A graph convolutional network (GCN) was integrated with the blockchain-based system to detect malicious nodes. Finally, we implemented our framework prototype on a locally simulated network. The analysis and experiment results show that the proposed scheme demonstrates the effectiveness and privacy of users in our framework.

This paper reports the design, implementation, and experimental phases of the EU H2020 QualiChain pilot “Staffing the Public Sector—The Case of Portugal”. The overall purpose of this pilot is to ensure the authenticity and integrity of the diplomas for all involved stakeholders and therefore to contribute to solving the diploma counterfeiting and/or falsification that is a great threat to the recruitment of qualified personnel. The main innovative aspect of this solution is the integration that is offered between an Academic Management System (the Fenix.edu platform) and a Blockchain (Ethereum) to automatically deploy diplomas. This solution helps the involved stakeholders trust the diplomas provided. The case study involves four different stakeholders and studies, specifically, the increase in their satisfaction in terms of diploma control, diploma veracity, and diploma credibility. The developed system was tested with external participants who were asked to follow a set of guidelines and complete a survey to assess their perceptions. All system interactions were recorded, and the data were analyzed. The results indicated that the participants successfully executed the guidelines and that a perception increase toward diploma control, veracity, and credibility was identified.

Blockchain and the programs running on it, called smart contracts, are increasingly applied in all fields where trust and strong certifications are required. Our work focuses on industrial applications of blockchains and not on cryptocurrencies or tokens. We use frameworks to compare public and permissioned blockchains specifically suited for industrial applications. We also propose a complete solution based on Ethereum to implement a decentralized application, putting together in an original way, components and patterns already used and proven. This solution is characterized by a set of validator nodes running the blockchain using Proof-of-Authority or similar efficient consensus algorithms, by the use of an explorer enabling users to check the blockchain state, and the source code of the smart contracts running on it. From time to time, the hash digest of the last mined block is written into a public blockchain to guarantee immutability. The right to send transactions is granted by validator nodes to users by endowing them with the Ethers mined locally. Overall, the proposed approach has the same transparency and immutability as a public blockchain, largely reducing its drawbacks.

In most popular public accessible cryptocurrency systems, the mining pool plays a key role because mining cryptocurrency with the mining pool turns the non-profitable situation into profitable for individual miners. In many recent novel blockchain consensuses, the deep learning training procedure becomes the task for miners to prove their workload. Thus, the computation power of miners will not purely be spent on the hash puzzle. In this way, the hardware and energy will support the blockchain service and deep learning training simultaneously. While the incentive of miners is to earn tokens, individual miners are motivated to join mining pools to become more competitive. In this paper, we are the first to demonstrate a mining pool solution for novel consensuses based on deep learning.

The mining pool manager partitions the full searching space into subspaces, and all miners are scheduled to collaborate on the Neural architecture search (NAS) tasks in the assigned subspace. Experiments demonstrate that the performance of this type of mining pool is more competitive than that of an individual miner. Due to the uncertainty of miners' behaviors, the mining pool manager checks the standard deviation of the performance of high reward miners and prepares backup miners to ensure completion of the tasks of high reward miners.

Easy access to data is one of the main avenues to accelerate scientific research. As a key element of scientific innovations, data sharing allows the reproduction of results and helps prevent data fabrication, falsification, and misuse. Although the research benefits from data reuse are widely acknowledged, the data collections existing today are still kept in silos. Indeed, monitoring what happens to data once they have been handed to a third party is currently not feasible within the current data sharing practices. We propose a blockchain-based system to trace data collections and potentially create a more trustworthy data sharing process. In this paper, we present the LUCE (License accoUntability and CompliancE) architecture as a decentralized blockchain-based platform supporting data sharing and reuse. LUCE is designed to provide full transparency on what happens to the data after they are shared with third parties. The contributions of this work consist of i) the design of a decentralized data sharing solution with accountability and compliance by design and ii) the inclusion of a dynamic consent model for personalized data sharing preferences and for enabling legal compliance mechanisms. We test the scalability of the platform in a real-time environment where a growing number of users access and reuse different datasets. Compared to existing data sharing solutions, LUCE provides transparency over data sharing practices, enables data reuse, and supports regulatory requirements. The experimentation shows that the platform can be scaled for a large number of users.

Nowadays, an increasing number of blockchain architectures provide well-promising protocols for pseudonymous online payments via proposed cryptocurrencies. Most of them suffer from a number of extensibility and scalability issues, as their capacity regarding the number of transactions they are capable of processing per second is limited. Security is also a challenge for this kind of architectures. This paper presents the design and implementation of the Adrestus system, a blockchain-based transaction system with a novel consensus mechanism that is able to tolerate Byzantine faults and is designed to scale without compromising system security. One of the main components of the Adrestus design is a consistent hashing mechanism for the efficient assignment of transactions on parallel regions, called zones, and for solving load balancing problems. We claim that the Adrestus blockchain system scales linearly without compromising system security and achieves its goals without introducing the unnecessary overhead and by eliminating energy and computational waste. Preliminary theoretical simulations and results reflect that Adrestus exceeds the average throughput of the most well-known cryptocurrencies like Bitcoin, and thus, it achieves a higher performance. In this paper, we present this proposed approach along with simulation results and examine the conditions for the proposed fault-tolerant system to meet safety and liveness.

Actual challenges with data in physical infrastructure include: 1) the adversity of its velocity based on access and retrieval, thus integration; 2) its value as its intrinsic quality; 3) its extensive volume with a limited variety in terms of systems; and finally, 4) its veracity, as data can be modified to obtain an economical advantage. Physical infrastructure design based on Agile project management and minimum viable products provides benefits against the traditional waterfall method. Agile supports an early return on investment that promotes circular reinvesting while making the product more adaptable to variable social-economical environments. However, Agile also presents inherent issues due to its iterative approach. Furthermore, project information requires an efficient record of the aims, requirements, and governance not only for the investors, owners, or users but also to keep evidence in future health & safety and other statutory compliance. In order to address these issues, this article presents a Validation and Verification (V&V) model for data marketplaces with a hierarchical process; each data V&V stage provides a layer of data abstraction, value-added services, and authenticity based on Artificial Intelligence (AI). In addition, this proposed solution applies Distributed Ledger Technology (DLT) for a decentralised approach where each user keeps and maintains the data within a ledger. The presented model is validated in real data marketplace applications: 1) live data for the Newcastle Urban Observatory Smart City Project, where data are collected from sensors embedded within the smart city via APIs; 2) static data for University College London (UCL)—Real Estate—PEARL Project, where different project users and stakeholders introduce data into a Project Information Model (PIM).

COVID-19 has changed almost all aspects of our lives. Governments around the world have imposed lockdowns to slow down the transmissions. Fortunately, we have found the vaccine, in fact, a good number of them. However, managing the testing and vaccination process of the total population is a mammoth job. However, there are always delays or data silo problems in multi-organizational work. Therefore, streamlining this process is vital to improve efficiency and save more lives. Because of its effective data sharing mechanism among different entities with a number of security features, blockchain can be an effective tool for different applications in the health sector. Furthermore, blockchain provides a distributed system along with greater privacy, transparency, and authenticity. In this article, we have presented a blockchain-based system that seamlessly integrates testing and vaccination systems, allowing the system to be transparent. The instant verification of any tamper-proof COVID-19 test result has been developed, which will serve as “Test Certificates”. A transparent and efficient vaccination system has also been exhibited and implemented as the “Digital Vaccine Passport” (DVP) system. The infection rate-based prioritization will ensure a transparent and fair vaccination process as well as tackle the distribution issue of the limited amount of vaccine. The comparative review with other existing works is also discussed, highlighting a clear difference from the existing works. Our proposed system is distinctive on the basis of prioritization of vaccines and seamless integration of test certificates and vaccine passports, which will aid in controlling the pandemic situation. This system will also be handy in the case of tackling any future pandemics initially.