Fault-tolerance is very important in cluster computing and has beenimplemented in many famous cluster-computing systems using checkpoint/restartmechanisms. But existent check-pointing algorithms cannot restore the sta...Fault-tolerance is very important in cluster computing and has beenimplemented in many famous cluster-computing systems using checkpoint/restartmechanisms. But existent check-pointing algorithms cannot restore the states of afile system when roll-backing the running of a program, so there are many restrictionson file accesses in existent fault-tolerance systems. SCR algorithm, an algorithmbased on atomic operation and consistent schedule, which can restore the states offile systems, is presented in this paper. In the SCR algorithm, system calls on filesystems are classified into idem-potent operations and non-idem-potent operations.A non-idem-potent operation modifies a file system's states, while an idem-potentoperation does not. SCR algorithm tracks changes of the file system states. It logseach non-idem-potent operation used by user programs and the information that canrestore the operation in disks. When check-pointing roll-backing the program, SCRalgorithm will revert the file system states to the last checkpoint time. By usingSCR algorithm, users are allowed to use any file operation in their programs.展开更多
Purpose-Whereas a human operator is hard to observe the networking infrastructure and its functions on a continuous basis,wireless sensor network(WSN)nodes must overcome faults and route the perceived data to the sink...Purpose-Whereas a human operator is hard to observe the networking infrastructure and its functions on a continuous basis,wireless sensor network(WSN)nodes must overcome faults and route the perceived data to the sink/base stations(BS).The main target of this research article is to ensure the fault-tolerance(FT)capability,especially for transmission of sensed data to its destinationwithout failure.Thus,through this paper,a fuzzy-based subordinate support(FSS)system is introduced as an additional feature to the existing optimized mobile sink improved energy efficient Power-Efficient Gathering in Sensor Information Systems(PEGASIS)-based(OMIEEPB)routing protocol,which lacks focus on ensuring the FT capabilities to the selected leaders of the corresponding chain.The central focus of FSS is to prevent the incident of fault,especially to the cluster heads.Design/methodology/approach-WSNs encounter several issues owing to random events or different causes such as energy exhaustion,negative influences of the deployed region,signal interference,unbalanced supply routes,instability of motes due to misalignments and collision,which ultimately intends the failure of the network.Throughout the past investigation periods,researchers gain an understanding of fault-tolerant strategies that may improve the data integrity or reliability,precision,energy efficiency,the life expectancy of the system and reduce/prevent the failure of deployed components.If that is the case,the maximum chances of data packets(sensed)needed to be transferred reliably and accurately to the sink node or BS are degraded.Findings-The FSS system utilizes the fuzzy logic concepts that have been proved to be beneficial since it permits several parameters to be combined effectively and evaluated.Here,near-point,residual energy,total operation time and past average processing time are considered as vital parameters.Moreover,the FSS system ensures the key performance activities of the network,such as optimization of response time,enhancing the data transmission展开更多
Electric power conversion system （EPCS）, which consists of a generator and power converter, is one of the most important subsystems in a direct-drive wind turbine （DD-WT）. However, this component accounts for the ...Electric power conversion system （EPCS）, which consists of a generator and power converter, is one of the most important subsystems in a direct-drive wind turbine （DD-WT）. However, this component accounts for the most failures （approximately 60% of the total number） in the entire DD-WT system according to statistical data. To improve the reliability of EPCSs and reduce the operation and maintenance cost of DD-WTs, numerous researchers have studied condition monitoring （CM） and fault diagnostics （FD）. Numerous CM and FD techniques, which have respective advantages and disadvantages, have emerged. This paper provides an overview of the CM, FD, and operation control of EPCSs in DD-WTs under faults. After introducing the functional principle and structure of EPCS, this survey discusses the common failures in wind generators and power converters; briefly reviewed CM and FD methods and operation control of these generators and power converters under faults; and discussed the grid voltage faults related to EPCSs in DD-WTs. These theories and their related technical concepts are systematically discussed. Finally, predicted development trends are presented. The paper provides a valuable reference for developing service quality evaluation methods and fault operation control systems to achieve high-performance and high-intelligence DD-WTs.展开更多
文摘Fault-tolerance is very important in cluster computing and has beenimplemented in many famous cluster-computing systems using checkpoint/restartmechanisms. But existent check-pointing algorithms cannot restore the states of afile system when roll-backing the running of a program, so there are many restrictionson file accesses in existent fault-tolerance systems. SCR algorithm, an algorithmbased on atomic operation and consistent schedule, which can restore the states offile systems, is presented in this paper. In the SCR algorithm, system calls on filesystems are classified into idem-potent operations and non-idem-potent operations.A non-idem-potent operation modifies a file system's states, while an idem-potentoperation does not. SCR algorithm tracks changes of the file system states. It logseach non-idem-potent operation used by user programs and the information that canrestore the operation in disks. When check-pointing roll-backing the program, SCRalgorithm will revert the file system states to the last checkpoint time. By usingSCR algorithm, users are allowed to use any file operation in their programs.
文摘Purpose-Whereas a human operator is hard to observe the networking infrastructure and its functions on a continuous basis,wireless sensor network(WSN)nodes must overcome faults and route the perceived data to the sink/base stations(BS).The main target of this research article is to ensure the fault-tolerance(FT)capability,especially for transmission of sensed data to its destinationwithout failure.Thus,through this paper,a fuzzy-based subordinate support(FSS)system is introduced as an additional feature to the existing optimized mobile sink improved energy efficient Power-Efficient Gathering in Sensor Information Systems(PEGASIS)-based(OMIEEPB)routing protocol,which lacks focus on ensuring the FT capabilities to the selected leaders of the corresponding chain.The central focus of FSS is to prevent the incident of fault,especially to the cluster heads.Design/methodology/approach-WSNs encounter several issues owing to random events or different causes such as energy exhaustion,negative influences of the deployed region,signal interference,unbalanced supply routes,instability of motes due to misalignments and collision,which ultimately intends the failure of the network.Throughout the past investigation periods,researchers gain an understanding of fault-tolerant strategies that may improve the data integrity or reliability,precision,energy efficiency,the life expectancy of the system and reduce/prevent the failure of deployed components.If that is the case,the maximum chances of data packets(sensed)needed to be transferred reliably and accurately to the sink node or BS are degraded.Findings-The FSS system utilizes the fuzzy logic concepts that have been proved to be beneficial since it permits several parameters to be combined effectively and evaluated.Here,near-point,residual energy,total operation time and past average processing time are considered as vital parameters.Moreover,the FSS system ensures the key performance activities of the network,such as optimization of response time,enhancing the data transmission
基金This work was supported by the National Key R＆D Program of China （Grant No. 2016YFF0203400）. The program focuses on studies on service quality monitoring and maintenance quality control technology for large wind turbines. The project leader is Professor Shoudao Huang. The authors are also grateful to the National Natural Science Foundation of China （Grant No. 51377050） for the financial support.
文摘Electric power conversion system （EPCS）, which consists of a generator and power converter, is one of the most important subsystems in a direct-drive wind turbine （DD-WT）. However, this component accounts for the most failures （approximately 60% of the total number） in the entire DD-WT system according to statistical data. To improve the reliability of EPCSs and reduce the operation and maintenance cost of DD-WTs, numerous researchers have studied condition monitoring （CM） and fault diagnostics （FD）. Numerous CM and FD techniques, which have respective advantages and disadvantages, have emerged. This paper provides an overview of the CM, FD, and operation control of EPCSs in DD-WTs under faults. After introducing the functional principle and structure of EPCS, this survey discusses the common failures in wind generators and power converters; briefly reviewed CM and FD methods and operation control of these generators and power converters under faults; and discussed the grid voltage faults related to EPCSs in DD-WTs. These theories and their related technical concepts are systematically discussed. Finally, predicted development trends are presented. The paper provides a valuable reference for developing service quality evaluation methods and fault operation control systems to achieve high-performance and high-intelligence DD-WTs.
