In this paper we propose a formal analytic graph-based description of zz-structures, an unusual, graphic-centric way of linking and organizing information. Starting from this formalized model, we make active and operative all the entities of the system, obtaining an actor-based model, called AZ. The actors are organized in different hierarchical levels and cooperate in order to achieve common goals and solve problems. In particular, the use of actor-based technology is helpful in enhancing distributed computing capabilities, and interoperability in grid systems. The combination of zz-structures and of cooperation activities of different actor classes allows us to define dynamic virtual organizations and to analyze some of issues related to system topological evolutions.
