A dialog flow notation for web-based applications

Increasingly, client-server applications are implemented as web-based applications with user interfaces consisting entirely of web pages or equivalent renderings on other presentation channels (e.g. mobile or speech-based devices). However, the page-based medium and the stateless pull communication impose restrictions on the user interface that often manifest themselves in unsatisfactory dialog control, i.e. possibly severely diminished usability. We therefore present a Dialog Flow Notation that allows developers to encapsulate sequences of multiple dialog steps into reusable dialog modules that can be nested arbitrarily, and to specify different interaction patterns for different devices. The notation is complemented with a Dialog Control Framework that manages dialog flows on multiple channels, leaving only the tasks of implementing the device-independent application logic, designing the interface pages, and specifying the dialog flow to the developer.