This paper was cited by \ref{Barross02}. It describes the system called CardMan, which is a framework for building and representing solution plans for physics exercises. The key idea is that argumentation is a typical mode of collaborative learning \ref{Buckingham94}. This software implements a class for Synchronization (coupling). It also provide a record and replay function of the action history which is also used as a transcripts for empirical purposes. The interesting engineering aspects of this Distributed Visual Language Environment (DVLE) are the structures used for managing the cards interchanged by the clients. Those are exchanged in a p2p mode but, more interestingly, are represented at three representational level: the specification level (content cards and connectors cards); the internal representational level (a graph structure with n-ary relations); and finally the external representational level, where card are generated accordingly to their specification.
A final interesting note is in the design of DVLE to work in accord with agents for intelligent support. The author affirm that “automathic processing should be clearly separated from the (group-)interactive functionality”. Their agent interface structure is constituted by a mediator and an interpreter agent: the former relates the visual card language to the underlying interpretation by translating card nets into specific interpreter representations and vice versa. In addition it aggregates information implicit in the user interface. The latter provide operational semantics for first order logic.