Stream processing has emerged as a useful technology for applications which require continuous and low latency computation on infinite streaming data.Since stream processing systems(SPSs)usually require distributed de...Stream processing has emerged as a useful technology for applications which require continuous and low latency computation on infinite streaming data.Since stream processing systems(SPSs)usually require distributed deployment on clusters of servers in face of large-scale of data,it is especially common to meet with failures of processing nodes or communication networks,but should be handled seriously considering service quality.A failed system may produce wrong results or become unavailable,resulting in a decline in user experience or even significant financial loss.Hence,a large amount of fault tolerance approaches have been proposed for SPSs.These approaches often have their own priorities on specific performance concerns,e.g.,runtime overhead and recovery efficiency.Nevertheless,there is a lack of a systematic overview and classification of the state-of-the-art fault tolerance approaches in SPSs,which will become an obstacle for the development of SPSs.Therefore,we investigate the existing achievements and develop a taxonomy of the fault tolerance in SPSs.Furthermore,we propose an evaluation framework tailored for fault tolerance,demonstrate the experimental results on two representative open-sourced SPSs and exposit the possible disadvantages in current designs.Finally,we specify future research directions in this domain.展开更多
This paper proposes a novel multi-pulse flexible-topology thyristor rectifier(FTTR) that can operate over a large voltage range while maintaining a low total harmonic distortion(THD) in the input current.The proposed ...This paper proposes a novel multi-pulse flexible-topology thyristor rectifier(FTTR) that can operate over a large voltage range while maintaining a low total harmonic distortion(THD) in the input current.The proposed multi-pulse FTTR has two operating modes:parallel mode and series mode.Irrespective of the mode in which it operates,the multi-pulse FTTR maintains the same pulses in the load current.To mitigate the harmonic injection into the AC mains,the topology-switching mechanism is then proposed.In addition,predictive current control is employed to achieve fast current response in both the transience and the transitions between modes.To verify the effectiveness of the multi-pulse FTTR as well as the control scheme,performance analysis based on an 18-pulse FTTR is investigated in detail,including fault tolerance evaluation,current THD analysis based on IEEE standard,and potential applications.Finally,a simulation model and the corresponding laboratory setup are developed.The results from both simulation and experiments demonstrate the feasibility of the proposed multi-pulse FTTR as well as the control scheme.展开更多
基金The work was supported by the National Key Research and Development Plan Project(2018YFB1003404)。
文摘Stream processing has emerged as a useful technology for applications which require continuous and low latency computation on infinite streaming data.Since stream processing systems(SPSs)usually require distributed deployment on clusters of servers in face of large-scale of data,it is especially common to meet with failures of processing nodes or communication networks,but should be handled seriously considering service quality.A failed system may produce wrong results or become unavailable,resulting in a decline in user experience or even significant financial loss.Hence,a large amount of fault tolerance approaches have been proposed for SPSs.These approaches often have their own priorities on specific performance concerns,e.g.,runtime overhead and recovery efficiency.Nevertheless,there is a lack of a systematic overview and classification of the state-of-the-art fault tolerance approaches in SPSs,which will become an obstacle for the development of SPSs.Therefore,we investigate the existing achievements and develop a taxonomy of the fault tolerance in SPSs.Furthermore,we propose an evaluation framework tailored for fault tolerance,demonstrate the experimental results on two representative open-sourced SPSs and exposit the possible disadvantages in current designs.Finally,we specify future research directions in this domain.
基金Project supported by the National Natural Science Foundation of China (No. 51177148)the Zhejiang Key Science and Technology Innovation Group Program,China (No. 2010R50021)
文摘This paper proposes a novel multi-pulse flexible-topology thyristor rectifier(FTTR) that can operate over a large voltage range while maintaining a low total harmonic distortion(THD) in the input current.The proposed multi-pulse FTTR has two operating modes:parallel mode and series mode.Irrespective of the mode in which it operates,the multi-pulse FTTR maintains the same pulses in the load current.To mitigate the harmonic injection into the AC mains,the topology-switching mechanism is then proposed.In addition,predictive current control is employed to achieve fast current response in both the transience and the transitions between modes.To verify the effectiveness of the multi-pulse FTTR as well as the control scheme,performance analysis based on an 18-pulse FTTR is investigated in detail,including fault tolerance evaluation,current THD analysis based on IEEE standard,and potential applications.Finally,a simulation model and the corresponding laboratory setup are developed.The results from both simulation and experiments demonstrate the feasibility of the proposed multi-pulse FTTR as well as the control scheme.
