Abstract: Disclosed are a method and system for evaluating sonar self-noise at a ship design stage. The method includes: building a ship structure full-scale geometric simulation model; acquiring loss factors and sonar transducer space outfitting acoustic absorption coefficient material parameters; acquiring mechanical excitation, hydrodynamic excitation, and propeller excitation; inputting the loss factors and the sonar transducer space outfitting acoustic absorption coefficient material parameters into an established statistical energy evaluation model, and applying a mechanical excitation to a face plate of foundation of the built ship structure full-scale geometric simulation model, applying a hydrodynamic excitation to the surface of a ship hull, and applying a propeller excitation to a stern shaft to perform calculation of sonar self-noise of a ship to obtain total spectral density level of the sonar self-noise; and evaluating spectral density level calculation results by index requirements.

Abstract: Disclosed are a method and system for evaluating sonar self-noise at a ship design stage. The method includes: building a ship structure full-scale geometric simulation model; acquiring loss factors and sonar transducer space outfitting acoustic absorption coefficient material parameters; acquiring mechanical excitation, hydrodynamic excitation, and propeller excitation; inputting the loss factors and the sonar transducer space outfitting acoustic absorption coefficient material parameters into an established statistical energy evaluation model, and applying a mechanical excitation to a face plate of foundation of the built ship structure full-scale geometric simulation model, applying a hydrodynamic excitation to the surface of a ship hull, and applying a propeller excitation to a stern shaft to perform calculation of sonar self-noise of a ship to obtain total spectral density level of the sonar self-noise; and evaluating spectral density level calculation results by index requirements.

Abstract: Disclosed is a method for a USB power receiving device selecting a power supply option. The method is performed by the USB power receiving device and includes: receiving N power data object(s) (PDO(s)) from a USB power supplying device, in which the N is a positive integer; checking whether at least one of M PDO(s) of the USB power receiving device matches at least one of the N PDO(s) according to a selection rule including a voltage requirement and a current-related requirement and accordingly generating a request data object (RDO), in which the M is a positive integer; and transmitting the RDO to the USB power supplying device to request the USB power supplying device to supply power to the USB power receiving device according to the RDO.

Abstract: Disclosed is a method for a USB power receiving device selecting a power supply option. The method is performed by the USB power receiving device and includes: receiving N power data object(s) (PDO(s)) from a USB power supplying device, in which the N is a positive integer; checking whether at least one of M PDO(s) of the USB power receiving device matches at least one of the N PDO(s) according to a selection rule including a voltage requirement and a current-related requirement and accordingly generating a request data object (RDO), in which the M is a positive integer; and transmitting the RDO to the USB power supplying device to request the USB power supplying device to supply power to the USB power receiving device according to the RDO.