The Cyranus-platform is an authoring framework for conversational interactive storytelling, developed within several projects. For instance, it was employed within the EU-project art-e-fact, “Virtual Humans with Social Intelligence” (a German-US research project commissioned by SAP research), partly within the German research project Virtual Human, and others.
One of the museum aplications that were build with the Cyranus-platform is depicted in the following figure:
One of the requirements of development of the Cyranus-platform was pragmatism. In particular within the art-e-fact project, we had fixed dates for displaying results as working and stable museum installations, so too risky technological experiments were out of question. Thus, the core architecture and the technologies chosen were conservative, and challenging features were built on top of the conservative choices.
The conservative choices were (a) a hierarchical architecture with a central control unit (“Narrator”), with only limited autonomy of the subordinate parts, (b) a directed graph was not the only control module, but it was always available, and (c) for chatting with the keyboard, a chatterbot (ALICE) was adapted.
Innovative features were built on top of these choices. Concerning the authoring process, the most interesting and fruitful development was to allow other control methods to activate states. The hierarchies of the Statechart were employed to encapsulate the range of action of these other control strategies. Thus, it was possible to use an arbitrary number of control strategies in parallel. In practice, we have employed mostly forward-chaining as an alternative.
If the directed graph was employed together with another control strategy, within a composite state of a Statechart, then a delegation chain took place: If the graph could not handle an event, it was handed over to this other control strategy.
With this system, it was possible (i) to combine branching stories with (ii) highly interactive sections displaying (iii) quite intelligent behavior, and (iv) to integrate some state-based chatting with stimulus-response-style chatting.
Concerning the authoring process, another important implication was that the Cyranus-platform allowed for a simple start of the authoring process, employing the directed graph, and then enabled a migration and addition of other control strategies, as the story idea evolves.
The architecture of the platform is as follows: