A novel method is developed to merge and disband groups in IP Multicast while retaining the original setup of their groups. It extends the semantic ofjoining or leaving a membershipfrom discrete members to group members in IP network. It has minimal impact on existing multicast trees and does not affect the operations of multicast routing protocols and the Internet Group Management (IGMP). It i...

In this paper, we consider the projective special linear group $PSL_2(59)$ and construct some 1-designs by applying the Key-Moori method on $PSL_2(59)$. Moreover, we obtain parameters of these designs and their automorphism groups. It is shown that $PSL_2(59)$ and $PSL_2(59):2$ appear as the automorphism group of the constructed designs.