An infrastructure for mobile information systems based on a fragmented object model

Abstract

Global information management systems based on the vision of the 'docuverse'-such as the World-Wide Web (WWW)-show that on-line access to vast amounts of distributed information is possible not only for the expert, but also for the end user. At the same time, the availability of affordable mid- and long-range wireless data communication services, based, e.g., on cellular phone technology, has put the vision of ubiquitous mobile information access within the reach of viable projects. It is now an interesting challenge to combine both concepts into a system model granting everyone ubiquitous access to the global information repository. However, problems such as low bandwidth and limited resources make this a non-trivial task. This paper describes MIS/O, an experimental mobile information system based on wireless data communication which has been developed at the Computer Graphics Center during 1994. MIS/O and its underlying concepts address the above mentioned problem areas by introducing a fragmented object model. This model provides the necessary mechanisms for a (partial) migration of object behaviour to the mobile system-acting as an intelligent data terminal-at runtime. In addition to conventional caching and compression techniques, this is required for coping with intrinsic system limitations and low communication bandwidth in an environment with a virtually unlimited number of information types and services such as the docuverse.