Extended social network

Currently social networks are becoming important for understanding the internal structure of social groups. In this paper we are concerned with social networks for virtual people(avatars) who live in virtual worlds. For example 'Second Life' is a typical system supporting our enjoyment of virtual life. Virtual people also have virtual friends, so there must be various kinds of social groups in the virtual space. But since there are no temporal or spatial limitations in virtual space, the social network of all of the virtual avatars will be very large. In addition, virtual people try to use various virtual objects in the virtual space. In this paper, we consider virtual objects as well as avatars in order to reveal the indirect relationships among avatars via virtual people. So we propose a more generalized social network which includes virtual people and objects, and their relationships. Also we propose a single simplification algorithm for a generalized social network, which will be very useful for providing a more abstract representation or hierarchical structure of a very large social network. In our experiment, we show that our extended social network is very useful and effective for investigating a very large and complicated social network.