  The Ubiquitous Interactor (UBI) addresses the problems of design and
development that arise around services that need to be accessed from many
different devices. In UBI, the same service can present itself with different
user interfaces on different devices. This is done by separating interaction
between users and services from presentation. The interaction is kept the same
for all devices, and different presentation information is provided for
different devices. This way, tailored user interfaces for many different
devices can be created without multiplying development and maintenance work. In
this paper we describe the system design of UBI, the system implementation, and
two services implemented for the system: a calendar service and a stockbroker
service.
