Hooman Tahayori

Email, as one the most popular Internet service is confronted with the plague of spam, which results in bandwidth, time and money waste. Moreover spam has evolved into a true security issue that enforces organizations to fight back in order to address security measures confidentiality, integrity and availability. To this end, we have proposed a dynamic model to classify incoming messages into five granules namely, spam, suspicious-spam, suspicious, suspicious-non-spam and non-spam, using interval type-2 fuzzy set methodologies augmented with the concept of general intervals. Despite the intrinsic complexities of higher order fuzzy sets, the error ratio of misclassification of the proposed method is noticeable. However it should be stressed that no single method can achieve one hundred percent precision, the proposed model should be used in conjunction with other complementing technologies.

Regarding the three dimensional nature of type-2 fuzzy sets their related operations are costly, in terms of time and computation, which is one of the main burdens among the popularity of type-2 fuzzy sets. In this paper we will provide a novel method for performing type-2 fuzzy set operations. We will prove that the operations would be simply performed based on the hyperplane of the highest degree of intersection of two type-1 fuzzy sets.