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76 results about "Master slave synchronization" patented technology

Master-slave synchronization method applicable to multi-hop wireless sensor network

This invention discloses a master-slave synchronization method applicable to a multi-hop wireless sensor network. In an initialization phase, entire network nodes are required to establish a hierarchical structure in the manner of distributing, and acquire levels each node belonged to, and father node and child node information. In a synchronization phase, each level of the father nodes broadcast a synchronization request frame level by level from a root node of the network to initiate a synchronization process, solve through a two-dimensional discrete Markov chain model to get an optimal value of a contention backoff window under the condition of different numbers of the child nodes, and incidentally notify the child nodes about the optimal value simultaneously. After receiving the synchronization request frame, the child nodes compete to reply a synchronization response frame according to the size of the optimal backoff window. After receiving the synchronization response frame, the father nodes compute a time deviation between the father nodes and the child nodes, and notify the child nodes about the time deviation through a synchronization acknowledgment frame. After receiving the synchronization acknowledgment frame, the child nodes adjust the local time so as to finish the synchronization process. The simulation result in EXata proves the validity of the method.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Directional beam based wireless network master-slave synchronization method

The invention discloses a directional beam based wireless network master-slave synchronization method. The directional beam based wireless network master-slave synchronization method comprises the steps of regarding a node which initiates time synchronization in the network as a master node; correspondingly regarding nodes synchronized with the master node as slave nodes; dividing a master-slave synchronization process into a coarse synchronization stage and a fine synchronization stage based on characteristics of directional beam transmission. In the coarse synchronization stage, the master node initiates a synchronization process through directional broadcasting of a coarse synchronization frame; and in the fine synchronization stage, clock slew of the slave nodes and the master node which receive the coarse synchronization frame successfully is removed through directional interaction between a fine synchronization request frame and a fine synchronization response frame, and the time synchronization is realized. After time synchronization of the slave nodes and the master node is finished, each slave node which serves as a master node broadcasts the coarse synchronization frame directionally to neighbor nodes and initiates the synchronization process for the neighbor nodes to further realize time synchronization among all the nodes in the network. The validity of the method is proved by a simulation experiment in the wireless network simulation environment EXata.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Method for controlling networked teleoperation system in consideration of limited system performance

The invention discloses a method for controlling a networked teleoperation system in consideration of limited system performance. The specific method is as follow: under network communication delay, alimited master-slave position synchronization error variable is defined on the basis of a non-linear networked teleoperation system model; on the basis of the defined error variable and a neural network, a self-adaptive neural network control policy for the teleoperation system is designed; and a Lyapunov equation is utilized for giving a self-adaptive neural network and parameter adjustment rule, ensuring that set performance requirement is met while the master-slave synchronization error tends to be converged at zero. By stably operating under the limited performance of the teleoperation system, the method disclosed by the invention ensures the safety of the system, solves the problems of low system convergence speed and low precision under a conventional teleoperation control policy, overcomes the uncertainty of a system model and the influence of outside interference on system performance, and enhances the transient and stable performance and anti-interference performance of the system. Moreover, the method simplifies the process of designing a controller, so that practical application is more benefited.
Owner:YANSHAN UNIV

Regenerative UTC (Universal Time Coordinated) atomic time ultrahigh precision time frequency synchronization network

InactiveCN102546072AHigh precisionAccuracy achieves high precisionTime-division multiplexSynchronization networksRubidium
The invention discloses a regenerative UTC (Universal Time Coordinated) atomic time ultrahigh precision time frequency synchronization network. The regenerative UTC atomic time ultrahigh precision time frequency synchronization network is connected with a time synchronization master station and a time synchronization slave station through optical fibers. An interprovincial and interurban primary communication network is established and borne on an optical-cable optical transport network. HTF-BITS equipment is respectively arranged on the time synchronization master station and the time synchronization slave station. A caesium clock Cs, a rubidium clock Rb, a DCXO (Digital Control X-tal Crystal Oscillator) or a VCXO (Voltage Control X-tal Crystal Oscillator) is arranged on each piece of HTF-BITS equipment. The ultrahigh precision time frequency synchronization or mutual synchronization between the caesium clocks is completed; or the master-slave synchronization between the caesium clocks and the rubidium clocks is completed; the mutual synchronization between the caesium clocks is completed; the master-slave synchronization between the rubidium clocks and the DCXOs is completed; the mutual synchronization between the DCXOs is completed; the master-slave synchronization between the DCXOs and the VCXOs is completed; and as long as the synchronization network normally operates, any node can be a regenerative UTC atomic time frequency standard. The invention provides the novel all-round underground high-precision time frequency synchronization network which is used for transmitting the high-precision time reference by an underground optical-cable optical transmission system without depending on sky time established by navigation systems such as a GPS (Global Positioning System), the Beidou and the like.
Owner:大唐电信(成都)信息技术有限公司

Data management method and system for centralized clearing system

ActiveCN104391899AImprove master-slave synchronization efficiencyImprove data backupDatabase management systemsSpecial data processing applicationsCache hit rateNoSQL
The embodiment of the invention discloses a data management method and a data management system for a centralized clearing system. The data management method according to the embodiment of the invention comprises the following steps of acquiring message data to be written; parsing the message data to be written to obtain message relational data and message content data; storing the message relational data in an RDBMS (relational database management system) database, storing the message content data in an NoSQL (not only structured query language) database, and establishing a message content data query index in the RDBMS database; acquiring a message reading request; acquiring the message relational data and the message content data query index from the RDBMS database according to the message reading request, and querying the message content data in the NoSQL database; reading message information after the message relational data and the message content data are combined. According to the embodiment of the invention, the IO (input/output) overhead of the RDBMS database is reduced, the query cache hit ratio of the RDBMS database is increased, and the master-slave synchronization efficiency of the RDBMS database is improved; meanwhile, the size of data stored in the RDBMS database is reduced, so that the backup and restoration speed of the data in the RDBMS database is increased.
Owner:CHINA CONSTRUCTION BANK

Data stream state monitoring alarm system based on master-slave synchronization

The invention discloses a data stream state monitoring and warning system based on master-slave synchronization, which belongs to the field of data governance and is connected with at least one data source and at least one user side. The system comprises a plurality of target databases which are respectively used for storing log data of data sources; the target data monitoring table comprises monitoring information corresponding to each data source; the server comprises a client used for reading log data in a master-slave synchronization mode and writing the log data into a message queue, and a consumption module used for updating a target data monitoring table when the message queue is changed; the alarm module is used for judging whether updating is abnormal or not and outputting push information when updating is abnormal; and the sending end is used for sending the push information to the user end. The method has the beneficial effects that the data is obtained through master-slave synchronization, so that the performance of the target database is not influenced; a plurality of data sources can be docked; the state of the data flow is monitored in real time, and the processing workload in the data governance process is reduced.
Owner:上海市大数据股份有限公司

Method and system for realizing fault tolerance of virtual machine

ActiveCN111400086AReduced Tail LatencyAvoid false synchronization of state differencesResource allocationHardware monitoringFault toleranceVirtualization
The invention provides a method and a system for realizing fault tolerance of a virtual machine. The method comprises the steps of: redundantly operating the virtual machine where an application program is located in a plurality of servers, selecting one server as a master virtual machine, using the rest servers as slave virtual machines, wherein the virtualization configurations of the master virtual machine and the slave virtual machines are the same, and the master virtual machine and the slave virtual machines are redundant backups for fault switching; and enabling the master virtual machine and the slave virtual machines to carry out redundancy processing on the user request, and maintaining the consistency of the external visible states of the master virtual machine and the slave virtual machines through a master-slave synchronization protocol. Compared with the prior art, according to the invention, an efficient master-slave synchronization protocol and an operating system cooperating with a virtual machine monitor are used; the method greatly reduces the tail time delay of user request processing, reduces the frequency of state difference caused by uncertainty of redundantoperation of the master and slave virtual machines, reduces the expenditure of state synchronization of the master and slave virtual machines, remarkably improves the overall throughput of an application program in a fault-tolerant system, and remarkably reduces the delay of request processing.
Owner:SHANGHAI JIAO TONG UNIV

A method of making an MFS distributed file system highly available

The invention discloses a method for making the MFS distributed file system have high availability. The MFS distributed file system used in the method adds a mirror main node and a metadata synchronization module on the original MFS original role and module; the MFS distributed file system comprises a mirror main node and a metadata synchronization module. The mirror master node is responsible forkeeping the state consistent with the master node. The metadata synchronization module is located between the master node and the mirror master node, which is responsible for synchronizing the metadata base data and the metadata incremental modification log, and verifying the authorization of the master node and the mirror master node. The invention transmits the reference metadata of the masternode and the incremental modification log by the master-slave synchronization mechanism to maintain the weak consistency of the metadata of the master node and the mirror node. When the primary node stops serving, the mirror node can quickly promote the primary node and provide storage services to ensure that the primary node is highly available, and at the same time, the operation can be rolled back, thus ensuring the high availability of the MFS file system services.
Owner:GEOVIS CO LTD

Data real-time association method supporting total update

The invention provides a real-time data association method supporting total update. The method includes a data acquisition module, a data management module, a Redis memory database, and a data association module, the data acquisition module acquires total data required to be synchronized from an external file or an external database and processes the total data; then, the data in the correspondingformat is transmitted to the data management module; the data management module processes the received data; inserting or updating the data into a Redis memory database; the Redis memory database stores various types of associated data, data synchronization is carried out in a master-slave mode, the data association module receives a data association query request, then an association result is queried from the Redis memory database, and after type conversion, the association result is returned to the data association query request. Under the condition of total data updating, the number of data updating in the Redis memory database is reduced, occupation of network and system resources during master-slave synchronization of the Redis memory database is greatly reduced, and the efficiencyof using the Redis memory database for data association can be greatly improved.
Owner:CNIS TECH CO LTD
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