1. Processing apparatus adapted to implement an artificial intelligence application, which application requires use of training sets having positive and negative examples, the apparatus comprising: at least one memory adapted to store data and/or instructions; at least one processor adapted to execute the following operations, using the at least one memory: recognizing and maintaining a set of positive examples for training; and upon completion of recognition of the set of positive examples, selecting a set of negative examples for training responsive to the set of positive examples.