Abstract: A charging base includes: a base seat installed on a floor surface; a columnar tower part provided on the base seat; a first support provided on the tower part and capable of supporting a vertical first electric vacuum cleaner; and a second support provided on the tower part and capable of supporting a vertical second electric vacuum cleaner. An electric vacuum cleaner system includes the charging base configured as described above, the vertical first electric vacuum cleaner, and the vertical second electric vacuum cleaner.

Abstract: A non-transitory computer-readable storage medium storing a navigation monitoring program that causes at least one computer to execute a process, the process includes acquiring direction information that indicates a direction of a vessel and position information that indicates a position of the vessel; and predicting whether or not the vessel navigates along a course by inputting the acquired direction information and the acquired position information to a prediction model generated by machine learning by using direction information and position information for each of a plurality of vessels that has navigated in the past and a correct answer label that indicates whether or not each of the plurality of vessels navigates along a course.