Abstract: Embodiments of this disclosure can provide a system and method for calibrating extrinsic parameters of roadside sensors for autonomous driving. During operation, a portable light-detection-and-ranging (lidar) unit can be brought to a sensor-installation site comprising one or more to-be-calibrated roadside sensors, and the portable lidar unit can scan outer surfaces of the to-be-calibrated roadside sensors from different angles to generate a stream of frames. The system can align, spatially, the stream of frames based on a local reference coordinate system, superimpose the aligned frames, and segment a point cloud associated with a to-be-calibrated roadside sensor. The system can determine extrinsic parameters of the to-be-calibrated roadside sensor with respect to the local reference coordinate system based on the segmented point cloud and convert the extrinsic parameters from the local reference coordinate system to a road-based coordinate system.

Abstract: Embodiments can provide a data-collection system for collecting training data for autonomous driving applications. The system can include an on-vehicle light-detection—and—ranging (lidar) unit mounted on a data-collection vehicle, a roadside lidar unit, a frame-alignment subsystem, and a frame-superimposing subsystem. The on-vehicle lidar unit is to collect a first stream of frames while the data-collection vehicle is in motion. The roadside lidar unit is to collect, while remaining stationary, a second stream of frames. The frame-alignment subsystem is to align the second stream of frames collected by the roadside lidar to the first stream of frames collected by the on-vehicle lidar in time and spatial domains. The frame superimposing subsystem is to superimpose a frame from the second stream of frames onto a corresponding frame from the first stream of frames, thereby facilitating enhancement of point clouds of objects in the first stream of frames.

Abstract: This application discloses a method, device, and apparatus for maintaining a wind turbine generator plant, which relates to the field of wind power generation. The method includes determining a failure of the wind turbine generator plant when the wind turbine generator plant enters a shutdown maintenance mode; determining a maintenance wind speed corresponding to the failure; adjusting one of blades of the wind turbine generator plant to reach a predetermined azimuth angle and lock an impeller of the wind turbine generator plant to maintain the wind turbine generator plant in a case where the failure belongs to a first type of failure and a real-time wind speed obtained is less than or equal to the maintenance wind speed corresponding to the failure, the first type of failure comprising a failure that requires to lock the impeller for maintenance and the predetermined azimuth angle being a different integral multiple of 30°.

Abstract: A method and an apparatus for liquid safety-detection by backscattering with a radiation source are provided that relate to a radiation detecting technology field.

Abstract: A method and an apparatus for liquid safety-detection by backscatter with a radiation source relate to a radiation detecting technology field.