Abstract: This application provides a data transmission method. The method includes: An electronic device first establishes an MPTCP connection to an application server, where the MPTCP connection includes two TCP connections. Then, the electronic device receives indication information from an application server, where the indication information includes a type identifier and a parameter. When the type identifier indicates a low data transmission delay requirement, the electronic device receives, in a first time period after the electronic device receives the indication information, the data stream by using a first TCP connection. When an accumulated data amount actually received by the electronic device in the first time period is less than a product of the parameter and duration corresponding to the first time period, the electronic device receives the data stream in a second time period by using both the two TCP connections.

Abstract: Complicated system fault diagnosis method and system based on a multi-stage model are provided. The method includes: establishing an integer-order mathematical model, a 0.1-level fractional order mathematical model, and a 0.01-level fractional order mathematical model of a permanent magnet synchronous motor system; designing an integer-order status observer based on the integer-order mathematical model, designing a 0.1-level fractional order status observer based on the 0.1-level fractional order mathematical model, and designing a 0.01-level fractional order status observer based on the 0.01-level fractional mathematical model; corresponding residual values can be obtained by the observers and compared with corresponding threshold values to judge whether there is a fault. The system includes first through third modules. Observers with different accuracy degrees are set up and the permanent magnet synchronous motor system is diagnosed through the observers.

Abstract: Complicated system fault diagnosis method and system based on a multi-stage model are provided. The method includes: establishing an integer-order mathematical model, a 0.1-level fractional order mathematical model, and a 0.01-level fractional order mathematical model of a permanent magnet synchronous motor system; designing an integer-order status observer based on the integer-order mathematical model, designing a 0.1-level fractional order status observer based on the 0.1-level fractional order mathematical model, and designing a 0.01-level fractional order status observer based on the 0.01-level fractional mathematical model; corresponding residual values can be obtained by the observers and compared with corresponding threshold values to judge whether there is a fault. The system includes first through third modules. Observers with different accuracy degrees are set up and the permanent magnet synchronous motor system is diagnosed through the observers.

Abstract: This application provides a data transmission method. The method includes: An electronic device first establishes an MPTCP connection to an application server, where the MPTCP connection includes two TCP connections. Then, the electronic device receives indication information from an application server, where the indication information includes a type identifier and a parameter. When the type identifier indicates a low data transmission delay requirement, the electronic device receives, in a first time period after the electronic device receives the indication information, the data stream by using a first TCP connection. When an accumulated data amount actually received by the electronic device in the first time period is less than a product of the parameter and duration corresponding to the first time period, the electronic device receives the data stream in a second time period by using both the two TCP connections.