Practical byzantine fault tolerance(PBFT)can reduce energy consumption and achieve high throughput compared with the traditional PoW algorithm,which is more suitable for a strongly consistent consortium blockchain.How...Practical byzantine fault tolerance(PBFT)can reduce energy consumption and achieve high throughput compared with the traditional PoW algorithm,which is more suitable for a strongly consistent consortium blockchain.However,due to the frequent communication among nodes,PBFT cannot realize scalability in large-scale networks.Existing PBFTbased algorithms still ignore performance and security.Therefore,we propose a secure and efficient practical byzantine fault tolerance based on double layers and multi copies(DM-PBFT).We design a reputation evaluation and node scheduling method for DMPBFT.And then we propose an adaptive node scheduling strategy based on the derived threshold values after analyzing the system communication complexity and security.Combining the above research,a node dynamic adjustment mechanism is proposed to freeze or adjust the node operation status according to the system environment.Simulation experiments show that the proposed mechanism can improve efficiency and increase the system’s throughput.展开更多
An approach to make heterogeneous devices cooperate with each other to provide ubiquitous service remains a longstanding challenge in ubiquitous environments. In addition, when multi-user request ubiquitous services s...An approach to make heterogeneous devices cooperate with each other to provide ubiquitous service remains a longstanding challenge in ubiquitous environments. In addition, when multi-user request ubiquitous services simultaneously, the arbitrariness in resource allocation process easily leads to non-equilibrium of qualities of multiuser's services. Thus, How to design an effective heterogeneous devices cooperation mechanism that meet the QoS requirements and also equilibrate QoS among multi-user's services becomes a very tough problem. In the paper, Equilibrium Index and Theil Utility function are imported to establish a multidevice equilibrium cooperation model, which is benefit for resource allocation in ubiquitous environments. Then a Theil-Equilibrium based Cooperation Mechanism for multi-service is proposed. Firstly, in order to simplify calculating, a dimensionless processing is introduced. After that, a cooperation approach with Theil-Utility Heuristic algorithm is designed to choose the best solution for the simplified model. At last, the mechanism is simulated in a smart home scenario. The simulation results show that this mechanism outperforms non-equilibrium method by improving almost 40% in internal equilibrium with just reducing 0-2% in the total utility ofall the requested ubiquitous services. These data show that the proposed mechanism performs well in equilibrating qualities of multi-user's ubiquitous services.展开更多
基金supported in part by Beijing Natural Science Foundation(L244010,251038)National Natural Science Foundation of China(92467203,62372050,62502041)+2 种基金CCF-Huawei Populus Grove Fund(TC202418)Fellowship of China National Postdoctoral Program for Innovative Talents(BX20240045)China Postdoctoral Science Foundation General Program(2025M773481).
文摘Practical byzantine fault tolerance(PBFT)can reduce energy consumption and achieve high throughput compared with the traditional PoW algorithm,which is more suitable for a strongly consistent consortium blockchain.However,due to the frequent communication among nodes,PBFT cannot realize scalability in large-scale networks.Existing PBFTbased algorithms still ignore performance and security.Therefore,we propose a secure and efficient practical byzantine fault tolerance based on double layers and multi copies(DM-PBFT).We design a reputation evaluation and node scheduling method for DMPBFT.And then we propose an adaptive node scheduling strategy based on the derived threshold values after analyzing the system communication complexity and security.Combining the above research,a node dynamic adjustment mechanism is proposed to freeze or adjust the node operation status according to the system environment.Simulation experiments show that the proposed mechanism can improve efficiency and increase the system’s throughput.
基金partially supported by the Funds for Creative Research Groups of China(61121061)National Natural Science Foundation of China(61302078,61272515)+3 种基金863 Program(2011AA01A102)Ph.D.Programs Foundation of Ministry of Education of China(20110005110011)Beijing Higher Education Young Elite Teacher Project(YETP0476)Fundamental Research Funds for the Central Universities(2012RC0609)
文摘An approach to make heterogeneous devices cooperate with each other to provide ubiquitous service remains a longstanding challenge in ubiquitous environments. In addition, when multi-user request ubiquitous services simultaneously, the arbitrariness in resource allocation process easily leads to non-equilibrium of qualities of multiuser's services. Thus, How to design an effective heterogeneous devices cooperation mechanism that meet the QoS requirements and also equilibrate QoS among multi-user's services becomes a very tough problem. In the paper, Equilibrium Index and Theil Utility function are imported to establish a multidevice equilibrium cooperation model, which is benefit for resource allocation in ubiquitous environments. Then a Theil-Equilibrium based Cooperation Mechanism for multi-service is proposed. Firstly, in order to simplify calculating, a dimensionless processing is introduced. After that, a cooperation approach with Theil-Utility Heuristic algorithm is designed to choose the best solution for the simplified model. At last, the mechanism is simulated in a smart home scenario. The simulation results show that this mechanism outperforms non-equilibrium method by improving almost 40% in internal equilibrium with just reducing 0-2% in the total utility ofall the requested ubiquitous services. These data show that the proposed mechanism performs well in equilibrating qualities of multi-user's ubiquitous services.
