The sharing of patients' locations is an important part in mobile medical services and modern smart healthcare. Although location sharing based on blockchains has advantages on decentralization and openness, there is also a challenge to guarantee the security and the privacy of locations recorded in a blockchain. To this end, this paper investigates the location sharing based on blockchains for telecare medical information systems. Firstly, we define the basic requirements of blockchain-based location sharing including decentralization, unforgeability, confidentiality, multi-level privacy protection, retrievability and verifiability. Then, using order-preserving encryption and merkle tree, we propose a blockchain-based multi-level location sharing scheme, i.e. BMPLS. The analysis results show that our scheme satisfies the above requirements. Finally, the performance of our scheme is evaluated and the experiment results show that our scheme is efficient and feasible for both patients and medical workers. In a word, our scheme can be applied to realize privacy-preserving location sharing based on blockchains for telecare medical information systems.
Currently, the Internet of Things (IoT) solutions are playing an important role in numerous areas, especially in smart homes and buildings, health-care, vehicles, and energy. It will continue to expand in various fields in the future. However, some issues limit the further development of IoT technologies. First, the battery-powered feature increases the maintenance cost of replacing batteries for IoT devices. Second, existing Cloud-IoT frameworks are not able to cope with emerging delay-constrained applications in the IoT system due to its centralized mode of operation and the considerable communication delay. Existing studies neither satisfy the demand for the quick response in timeconstraint IoT applications nor fundamentally solving the problem of energy sustainability. Therefore, this paper studies the problem of energy sustainability and timeliness in IoT system. Based on Energy Harvesting Technologies (EHT), the Green and Sustainable Mobile Edge Computing (GS-MEC) framework is proposed to make IoT devices self-powered by utilizing the green energy in the IoT environment. In this framework, we formulate the problem of minimizing response time and packet losses of tasks under the limitation of energy queue stability to improve the timeliness and reliability of task processing. Additionally, the dynamic parallel computing offloading and energy management (DPCOEM) algorithm is designed to solve the problem based on the Lyapunov optimization technology. Finally, theoretical analysis demonstrates the effectiveness of the proposed algorithm, and the numerical result of simulation shows that the average performance of the proposed algorithm is an order of magnitude better than state-of-the-art algorithms.Index Terms-Mobile edge computing, internet of things (IoT), partial computation offloading, energy harvesting, resource allocation, lyapunov optimization.
I. INTRODUCTIONI NTERNET of Things (IoT) solutions are playing an important role in numerous areas, especially in smart homes, smart buildings, healthcare, vehicles, and energy. These areas are defined as the sectors that are currently utilizing the IoT to the Manuscript
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