14. The apparatus of claim 13 , wherein the processor circuit is configured, during the generation of the weighted singleton histogram, for ordering the singletons from a largest total characters to a smallest total characters of the singletons.
15. The apparatus of claim 14 , wherein, in computing the total popularity score of each singleton, the processor circuit is configured to ensure that the popularity of a small character singleton does not increase if it is part of a larger character singleton.