P1251950918UKNwe

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PLUMB An Interface for Users Who Are Blind to
Display, Create, and Modify Graphs
Matthew Calder Robert F. Cohen Jessica Lanzoni

• Goals
• To assist visually impaired users to understand
  relational data represented as graphs.
• The system should allow active exploration of
  drawn graphs by blind users
• The system should allow blind (as well as
  sighted) users to create and modify graphs.
• Implemented on a tablet PC using widely
  available hardware and software Features
• Audio cues to assist navigation
• Exploration with the Tablet pen
• Keyboard shortcuts which trigger sound events
  like the pen system
• Search and jump between nodes
• Change graph focus based on pen position
• Simple graph editing such as adding and removing
  nodes and edges
• Navigation
• Pen tracing teaches geographical and geometrical
  relationships between nodes
• Keyboard exploration allows quick understanding
  of relationships between adjacent graph elements
  but sacrifices sense of geometry and topological
  relationships

• Applications
• Computer Science and STEM (Science, Technology,
  Engineering and Math) education
• Diagram communication
• Map reading
• Trials
• We have completed a very preliminary series of
  trials
• Three visually impaired users IT
  professionals and a Computer Science Student
• Goal to assess general effectiveness are we
  on the right track? How can this be implemented
  as an educational tool?
• Participants succeeded in all tasks
• Participants were able to learn the system
  quickly, averaging 41 seconds to traverse from
  one node to another by the third test.
• Participants report positive experiences
• Conclusion
• Our immediate research plan is to perform
  usability tests. In the future we hope to
  investigate features of input devices such as the
  stylus pen of a Tablet PC to give user more
  control over the interface.

Figure 1. Screenshot of a PLUMB Euro-Map.

• Searching
• Users can search based on Node keywords or
  identifiers. The selected node changes with
  search selection and responds with audio
  feedback.
• Users receive information about a node and may
  either move directly to the node, or have the
  node moved under the pen position to start
  keyboard or pen navigation, which alleviates
  random access difficulty.

• Audio Formats and Presentation
• Combination of MIDI sounds, synthesized speech,
  and pre-recorded audio files
• Vary pitch, timbre, and loudness to guide user
• Continuous tone indicates contact with an edge
• Vibrato effect indicates movement
  towards vertices
• Synthetic speech to read labels and tips
• Prerecorded sounds for significant events

Acknowledgments We would like to thank Nancy
Lightbody and the Eastern Alliance in Science,
Technology, Engineering, and Mathematics (EAST)
for supporting us in this work. We would also
like to thank Valerie Haven for useful discussion
and feedback that helped us in designing the
system.