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An Investigation of Usability Issues with Mobile Systems Using a Mobile Eye Tracker. thesis by Marie Norlien International University in Germany Thesis supervisors: Prof. Dr. Anthony Jameson & Prof. Dr. Karl Rohr. Outline. Introduction Mobile eye tracker - PowerPoint PPT Presentation
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An Investigation of Usability Issues with
Mobile Systems Using a Mobile Eye Tracker
thesis byMarie Norlien
International University in GermanyThesis supervisors:
Prof. Dr. Anthony Jameson & Prof. Dr. Karl Rohr
Outline Introduction Mobile eye tracker Study performed of mobile
systems with a mobile eye tracker Conclusion
What is left to do Acknowledgements
Introduction Mobile systems raise many usability
issues that are not yet well understood. One technique for acquiring data relevant
to these issues is the use of a head-mounted mobile eye tracker
The goals of this thesis are To explore the potential and limitations of an
eye tracker in example studies of one or more typical mobile systems
To contribute some insights into particular usability problems that arise with those systems.
Outline Introduction Mobile eye tracker Study performed of mobile
systems with a mobile eye tracker Conclusion
What is left to do Acknowledgements
Eye tracker ASL Model 501 mobile eye tracker
Worn on users body One camera records the scene the
user is looking at; the other camera records the user’s eye movements
Eye tracker Strengths
Subject is free to move without losing accuracy of calibration
Mobile, within the range of the video receiver Subject can wear glasses
Limitations Subject is wearing many pieces of equipment,
which can be uncomfortable Difficult to calibrate and set up initially Viewing plane is restricted to the view of the
scene camera Cannot use outside
Eye tracker Calibration process
Subjects must be in a fixed position during calibration for the best recording of accurate data
The subject’s eye must not be obstructed by the subject’s eyelid
For example, the eyelid mostly covers the eye when a subject is looking down at a Pocket PC
Eye tracker Potential barriers to accurate calibration
Physical movement of the subject Even slight movement unnoticed by the subject
Excessive overhead light, sunlight, or spot lighting
Inadequate pupil and/or corneal reflection Solutions
Good Calibration methodology Subject should be fixed during calibration
Preventing light with the use of a sun-umbrella, dark walls, and anti-glare calibration surfaces
Outline Introduction Mobile eye tracker Study performed of mobile
systems with a mobile eye tracker Conclusion
What is left to do Acknowledgements
Study performed We analyzed two types of systems
Xybernaut – a small handheld PC with a basic indoor navigation system based on infrared sensors
REAL software developed by the Department of Computer Science, Saarbrücken University
The Compaq Ipaq or Hewlett-Packard (HP) Jornada pocket PC installed with market Global Positioning System (GPS) hardware and software
Study performed Xybernaut
Functionality includes indoor navigation via maps visible to the user from the system screen
The system is configured for a planned route in the Computer Science department at Saarbrücken University
Investigate how a user can manage multi-tasking with a mobile system
Study performed Xybernaut
Xybernaut hardware with REAL software
Study performed Pocket PC
Functionality includes outdoor navigation via a map visible to the user from the pocket PC screen, which the user can manipulate via menus and icons
Compared the functionality of two already existing market GPS navigation systems
World Navigator by Teletype GPS Destinator Personal Navigation System by RACO
Industries Investigate how user-friendly and intuitive
each interface is
Study performed Pocket PC
Compaq Ipaq hardware with
Destinator software
HP Jornada hardware with Teletype software
Study performed Results analyzed
Interview with subject while viewing each video recording
Targeted Questions Event Tables
From the videos, each event was logged systematically (begin & end time)
PERT diagrams From videos and Event Tables the following were
derived 3 diagrams to describe general case behaviors 2 diagrams to describe multi-tasking
Pocket PC evaluation
Study performed Event table example
Study performed Event Tables Summary
Main difference in subjects “Event-driven”
Interested in starting to perform the task Once there was an event, the user adjusted
their plan to solve the task “Plan-driven”
Developing a strategy for each task through map dragging
Having an understanding how they are positioned on the map relative to the environment
Study performed PERT diagram example
Study performed PERT diagrams summary
3 possible answers why users perform tasks sequentially vs. Multi-tasking
The user may find it too hard to perform the actions with the system
The user finds the task so demanding cognitively that the user must focus on one behavior at a time in order to manage the demands
The user needs further information from the system before it makes sense to move forward.
Study performed Pocket PC summary
How the menus should appear and work (4 Usability principles; Dix, et al., 1997)
Familiarity Generalizability Predictability Task Migratability
General comments regarding problems encountered while walking
Outline Introduction Mobile eye tracker Study performed of mobile
systems with a mobile eye tracker Conclusion
What is left to do Acknowledgements
Conclusion To understand the concepts of
multitasking applied to a mobile system There are three basic guidelines
Consider possible uses in the environment of the system in combination with various user behaviors
Consider including the possibility of extraordinary events occurring with the system
Consider situations were the user should not focus their attention on using the system
Jameson, A. (2002). User Multitasking as a Design Challenge for Mobile Multimodal Systems. ITRW on Multi-Modal Dialogue in Mobile Environments
Kloster Irsee, 17-19 June 2002
Conclusion Eye tracking can provide additional
valuable information to a well designed usability study in various structured environments leading to important usability discoveries regarding a given mobile system Despite its limitations User interfaces – PocketPC Navigation
Software Identifies the complexity of user Multi-tasking
while using a mobile system
Conclusion What is left to do
Find the link to Multi-modal systems Struck from thesis title Multi-tasking?
Conclusion Acknowledgements
Thank you to everyone, it would not have been possible without you.
Prof. Dr. Anthony Jameson, DFKI GmbH (German Research Center for Artificial Intelligence)
Prof. Dr. Karl Rohr, International University in Germany
Kerstin Klöckner, DFKI GmbH, Researcher The department of computer science,
Saarbrücken University. Christoph Stahl, Rainer Wasinger, and Christian
Müller
Questions ?