  Both FCM and PCM clustering methods have been widely applied to pattern
recognition and data clustering. Nevertheless, FCM is sensitive to noise and
PCM occasionally generates coincident clusters. PFCM is an extension of the PCM
model by combining FCM and PCM, but this method still suffers from the
weaknesses of PCM and FCM. In the current paper, the weaknesses of the PFCM
algorithm are corrected and the enhanced possibilistic fuzzy c-means (EPFCM)
clustering algorithm is presented. EPFCM can still be sensitive to noise.
Therefore, we propose an interval type-2 enhanced possibilistic fuzzy c-means
(IT2EPFCM) clustering method by utilizing two fuzzifiers $(m_1, m_2)$ for fuzzy
memberships and two fuzzifiers $({\theta}_1, {\theta}_2)$ for possibilistic
typicalities. Our computational results show the superiority of the proposed
approaches compared with several state-of-the-art techniques in the literature.
Finally, the proposed methods are implemented for analyzing microarray gene
expression data.
