Fall 2002 CS/PSY 6750 1

Dialog Design 3How to use a PDA

Fall 2002 CS/PSY 6750 2

Personal Digital Asst. (PDA)

Palm VII

HP JornadaHandspring Visor

Palm IIIc

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 andinterpretation

• Like a sketch padExample• 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• www.tegic.com/t9

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• 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 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 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 gesturesthat 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