Developed in 1997 for automatic reservation of tickets, IRENA is a dialogue system created by the team of Professor Nomura at the Kyushu Institute of Technology (Kyutech). The system analyses the sentences spoken by the user and generates suitable answers with the aim being ticket reservation. The system therefore has to manage navigation in the dialogue, understand the requests, and look for answers in a database.
Navigation in the dialogue is managed using dialogue frames. For request disambiguation the software works in a fuzzy logic framework, for language ambiguities as well as for logic ambiguities, which enables it to generate questions that could make the request more precise. To do this, a fuzzy function is assigned to every linguistic expression (e.g. "about", "from", etc...) and a fuzzy integration gives the representation of the total request.
The order of expressions, spontaneous utterances, refusals and other linguistic expressions also affect the final fuzzy function.