The Companions: Hybrid-World Approach

The Companions Hybrid-World model defines a new methodology for dialogue. Previous systems were based on a closed world assumption whereby the knowledge of the dialogue system is stored in a knowledgebase and used throughout the conversation. The Hybrid-World model is still based around a knowledgebase (which is used throughout the interaction with the user) but if the user starts talking about a topic which is not found in the knowledgebase, the system is capable of gathering information from the online world. This information is then used to enrich the knowledgebase and forms the basis of a reply to the user. The system uses mainly two approaches; the first approach is to harvest information from known sites using predefined wrappers. The second approach is to seek information with the help of search engines, extract the relevant parts and use those to provide a reply to the user. This approach of using a combination of a close-world model and an open-world model (when needed) proved itself to be very effective when engaging in dialogue with the user since it is not only restricted to the knowledge in the knowledgebase but can technically use all the relevant information available on the web.