Computer Laboratory

Technical reports

Visualisation, interpretation and use of location-aware interfaces

Kasim Rehman

May 2005, 159 pages

This technical report is based on a dissertation submitted November 2004 by the author for the degree of Doctor of Philosophy to the University of Cambridge, St Catharine’s College.


Ubiquitous Computing (Ubicomp), a term coined by Mark Weiser in the early 1990’s, is about transparently equipping the physical environment and everyday objects in it with computational, sensing and networking abilities. In contrast with traditional desktop computing the “computer” moves into the background, unobtrusively supporting users in their everyday life.

One of the instantiations of Ubicomp is location-aware computing. Using location sensors, the “computer” reacts to changes in location of users and everyday objects. Location changes are used to infer user intent in order to give the user the most appropriate support for the task she is performing. Such support can consist of automatically providing information or configuring devices and applications deemed adequate for the inferred user task.

Experience with these applications has uncovered a number of usability problems that stem from the fact that the “computer” in this paradigm has become unidentifiable for the user. More specifically, these arise from lack of feedback from, loss of user control over, and the inability to provide a conceptual model of the “computer”.

Starting from the proven premise that feedback is indispensable for smooth human-machine interaction, a system that uses Augmented Reality in order to visually provide information about the state of a location-aware environment and devices in it, is designed and implemented.

Augmented Reality (AR) as it is understood for the purpose of this research uses a see-through head-mounted display, trackers and 3-dimensional (3D) graphics in order to give users the illusion that 3-dimensional graphical objects specified and generated on a computer are actually located in the real world.

The system described in this thesis can be called a Graphical User Interface (GUI) for a physical environment. Properties of GUIs for desktop environments are used as a valuable resource in designing a software architecture that supports interactivity in a location-aware environment, understanding how users might conceptualise the “computer” and extracting design principles for visualisation in a Ubicomp environment.

Most importantly this research offers a solution to fundamental interaction problems in Ubicomp environments. In doing so this research presents the next step from reactive environments to interactive environments.

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BibTeX record

  author =	 {Rehman, Kasim},
  title = 	 {{Visualisation, interpretation and use of location-aware
  year = 	 2005,
  month = 	 may,
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  number = 	 {UCAM-CL-TR-634}