1. Dialog Design 3 How to use a PDA
Fall 2002
CS/PSY 6750

2. Personal Digital Asst. (PDA)
Palm VII
Palm IIIc
Handspring Visor
HP Jornada
Apple Newton (1993)
Fall 2002
CS/PSY 6750

3. PDAs Becoming more common and widely used
Smaller display (160x160), (320x240)
Few buttons, interact through pen
Estimate: 14 million shipped by 2004
Improvements
Wireless, color, more memory, better CPU, better OS
Palmtop versus Handheld
Fall 2002
CS/PSY 6750

4. No Shredder…
Fall 2002
CS/PSY 6750

5. Input Pen is dominant form Three main techniques
Free-form ink
Soft keyboards (tapping)
Recognition systems
Also can connect keyboard
Fall 2002
CS/PSY 6750

6. Free-form Ink Ink is the data, take as is
Human is responsible for understanding and interpretation
Like a sketch pad
Example
Digital Ink - CMU
video, CHI ‘98
Flatland - Xerox PARC
video, CHI ‘99
Fall 2002
CS/PSY 6750

7. Soft Keyboards Common on PDAs and mobile devices Many varieties
Tapping interface
Stroking interface
Fall 2002
CS/PSY 6750

8. Tapping Interface Presents a small diagram of keyboard
You click on buttons/keys with pen
QWERTY vs. alphabetical
Tradeoffs?
Alternatives?
Fall 2002
CS/PSY 6750

9. Tegic Communications-T9
Tapping interface that uses phone pad
You press out letters of your word, it matches the most likely word, then gives optional choices
Used in mobile phones
Fall 2002
CS/PSY 6750

10. Cirrin Developed by Jen Mankoff (GT->Cal)
Word-level unistroke technique
Fall 2002
CS/PSY 6750

11. Recognition Systems Handwriting Recognition
Recognizing letters and numbers
Special symbols
Handwriting Recognition
Lots of systems (commercial too)
English, kanji, etc.
Not perfect, but people aren’t either!
People - 96% handprinted single characters
Computer - >97% is really good
OCR (Optical Character Recognition)
Fall 2002
CS/PSY 6750

12. Recognition Issues Off-line vs. On-line Bitmapped vs. Vectorized
Off-line: After all writing is done, speed not an issue, only quality
On-line: Must respond in real-time
Bitmapped vs. Vectorized
Bitmapped: Usually off-line, like OCR
Vectorized: On-line, uses angle, direction, speed, pressure, acceleration, etc.
Fall 2002
CS/PSY 6750

13. More Issues Boxed vs. Free-Form input Printed vs. Cursive
Sometimes encounter boxes on forms
Printed vs. Cursive
Cursive is much more difficult
Letters vs. Words
Cursive is easier to do words
Using context & words can help
Usually requires existence of a dictionary
Check to see if word exists
Consider 1/I/l
Training - Many systems improve a lot with training data
Fall 2002
CS/PSY 6750

14. Special Alphabets Graffiti - Unistroke alphabet on Palm PDA
Experience?
Other alphabets or purposes
Gestures for commands
Fall 2002
CS/PSY 6750

15. Pen Gesture Commands - Might mean delete
Define a series of (hopefully) simple drawing gestures that mean different commands in a system
Fall 2002
CS/PSY 6750

16. Pen Use Modes
Often, want a mix of free-form drawing and special commands
Might use visible mode switch
Might have pen action buttons/switches
Fall 2002
CS/PSY 6750

17. Error Correction Having to correct errors can slow input tremendously
Strategies
Erase and try again
n-best list
...
Fall 2002
CS/PSY 6750

18. Interesting Applications
Signature verification
Note-taking
Academic course
Corporate meeting
Sketching systems
Designers’ aids
Example
Silk - J. Landay, CMU
Video, CHI ‘96
Fall 2002
CS/PSY 6750