Abstract: A method of and apparatus for performing a topdressing operation on an agriculture field have been provided. The method comprises the steps of: individually and continuously taking pictures of crops planted on a field to obtain crop picture data; processing the crop picture data of each crop to investigate the growing state of each crop; performing a topdressing operation in view of the growing state of each crop. The apparatus comprises a movable main body such as a tractor; a topdressing device provided on the rear side of the movable main body; a video camera provided on the front side of the movable main body; a picture data processing computer adapted to process picture data fed from the video camera so as to measure the leaf size of each crop; a topdressing operation controlling computer adapted to produce a command to the topdressing device to control an amount of a fertilizer to be applied to a crop.

Abstract: Disclosed is a system for controlling the position of a floating rig that permits holding the rig at a position optimum to an excavation riser even if a position signal of the floating rig is not received, provided that the angles of inclination at the upper and lower ends of the riser are detected. In the method of controlling the position of a floating rig, the floating rig 10 is joined to a well head 14 at the sea bottom by an excavation riser 16, and the rig 10 is driven to a corrected position by thrusters or a combination of thrusters and a propulsion system. A neural network is allowed to learn in advance the position information of the floating rig accompanying the behaving characteristics of the excavation riser.