The ghost in the shell paradigm for virtual agents and users in collaborative virtual environments for training

In Collaborative Virtual Environment for Training (CVET), different roles need to be played by actors , i.e. virtual agents or users. We introduce in this paper a new entity, the Shell , which aims at abstracting an actor from its embodiment in the virtual world. Thus, using this entity, users and virtual agents are able to collaborate in the same manner during the training. In addition to the embodiment's control, the Shell gathers and carries knowledge and provides interaction inputs. This knowledge and those inputs can be accessed and used homogeneously by both users and virtual agents to help them to perform the procedure. In this paper, we detail the knowledge mechanism of the Shell as this knowledge is a crucial element for both collaboration and learning in the CVET context. Furthermore, we also validate our exposed model by presenting an operational implementation in an existing CVET and discuss of its possible usages.