A Mark-Up Language and Interpreter for Interactive Scenes for Embodied Conversational Agents

Our research seeks to provide embodied conversational agents (ECAs) with behaviors that enable them to build and maintain rapport with human users. To conduct this research, we need to build agents and systems that can maintain high levels of engagement with humans over multiple interaction sessions. These sessions can potentially extend to longer periods of time to examine long-term effects of the virtual agent's behaviors. Our current ECA interacts with humans in a game called "Survival on Jungle Island." Throughout this game, users interact with our agent across several scenes. Each scene is composed of a collection of speech input, speech output, gesture input, gesture output, scenery, triggers, and decision points. Our prior system was developed with procedural code, which did not lend itself to rapid extension to new game scenes. So to enable effective authoring of the scenes for the "Jungle" game, we adopted a declarative approach. We developed ECA middleware that parses, interprets, and executes XML files that define the scenes. This paper presents the XML coding scheme and its implementation and describes the functional back-end enabled by the scene scripts.