Extracting Co-locator context

Having reliable context sources is very important for context-aware applications and the devices around a user can be a useful context for many applications. While the importance of `devices around' as a context has been highlighted many times, to the best of our knowledge, there is no systematic mechanism reported to identify and capture this context. In this paper we report our mechanism for extracting patterns that we call co-locators from the surrounding Bluetooth devices. The co-locator context can then be used as an indication about the user's surroundings. The context can be directly associated with user behavior in the surroundings, which in turn can be used for recommendation purposes. The context can also be used as a supplemental location indicator in the absence of other location mechanisms such as GPS. We then show that our experimental results support the value of using extracted co-locator patterns as good supplemental location indicators for several applications.