1. A method comprising: preparing a discriminator to be used for discriminating partial data; extracting a plurality of partial data from learning data; extracting at least one local data in each of the plurality of partial data; classifying the plurality of partial data by the discriminator to obtain a discrimination degree related to a difference between the at least one local data and a decision boundary of the discriminator for each of the plurality of partial data; evaluating a usefulness degree of the extracted partial data based on the discrimination degree; selecting at least a portion of the plurality of partial data to be used to be associated with the discriminator from the plurality of partial data based on the usefulness degree; and recording information of the selected partial data as an example to the discriminator.