Resumen
The authors have plagiarized part of a paper that had already appeared in IEEE Transactions on Knowledge and Data Engineering, 28(2), 411?424. doi:10.1109/tkde.2015.2485222. One of the conditions of submission of a paper for publication is that authors declare explicitly that their work is original and has not appeared in a publication elsewhere. As such this article represents a severe abuse of the scientific publishing system. Apologies are offered to readers of the journal that this was not detected during the submission process.