Delivering Real-World Ubiquitous Location Systems

Borriello, G., Chalmers, M., LaMarca, A., and Nixon, P. Delivering real-world ubiquitous location systems. Commun. ACM 48, 3 (2005), 36–41.

This paper emphasize on the practical aspects of getting location-enhanced application deployed on existing devices without installing special infrastructure. It provides an overview of different types of ubiquitous location system. Based on two case studies, the authors reveal some interesting issues in the deployment of location-aware systems such as:

Edinburgh is an old city with many narrow streets and high buildings; its latitude of 55° north—almost as far north as Alaska—accentuates the urban canyon effects that hamper GPS.
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On average, one or more access points were detected 48% of the time, and Place Lab could provide an accurate location. Two or more access points were detected for only 22% of the time. Indeed, the overall detection rate increased from 48% to 69% when excluding period of time visitors appeared to be indoors.
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The game designers were surprised, for example, that rain, snow, and leaves on trees strongly affect WiFi and GPS.
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The transfer of packets to and from access points can show significant asymmetry, and high packet loss can occur despite apparent network access.

Even if not standing in opposition to research aimed at improving accuracy and broadening availability, the authors suggest that we should offer pragmatic solutions while we continue to improve, adapt, evaluate the underlying technology of ubiquitous location systems.

Relation to my thesis: A reference I can use in a position paper for the workshop on Common Models and Patterns for Pervasive Computing to highlight the issues of deploying a WiFi-based location system such as CatchBob!. Besides the issues and challenges mentioned in this paper, I will add (among others things) the the uniqueness capabilities of pervasive devices.