Abstract: Location based or "context aware" computing is becoming
increasingly recognized as a vital part of a mobile computing environment. As a
consequence, the need for location-management middleware is widely recognized
and actively researched. Location-management is frequently offered to the application through
a "location API" (e.g. JSR 179) where the mobile unit can find out its own
location as coordinates or as "building, floor, room" values. It is then up to
the application to map the coordinates into a set of localized variables, e.g.
direction to the nearest bookshop or the local timezone. It is the opinion of
the authors that a localization API should be more transparent and more
integrated: The localized values should be handed to the application directly,
and the API for doing so should be the same as the general storage mechanisms.
Our proposed middleware for location and context management is built
on top of Mobispace. Mobispace is a distributed tuplespace made for mobile
units (J2me) where replication between local replicas takes place with a
central server (over GPRS) or with other mobile units (using Bluetooth). Since
a Bluetooth connection indicates physical proximity to another node, a set of
stationary nodes may distribute locality information over Bluetooth
connections, and this information may be retrieved through the ordinary
tuplespace API. Besides the integration with the general framework for communication
and coordination the middleware offers straightforward answers to questions
like: Where is node X located? Which nodes are near me? What is the trace of
node Y?
