1 / 59

Alternate Keyboards for Text Entry – And How to Evaluate Them

Alternate Keyboards for Text Entry – And How to Evaluate Them. I. Scott MacKenzie. Plan. Background Keyboards Evaluation Case study. Background. HUMAN-COMPUTER INTERACTION GUIs Mouse input Direct manipulation. MOBILE COMPUTING Pen-based input Handwriting recognition

Download Presentation

Alternate Keyboards for Text Entry – And How to Evaluate Them

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Alternate Keyboards for Text Entry – And How to Evaluate Them I. Scott MacKenzie

  2. Plan • Background • Keyboards • Evaluation • Case study

  3. Background

  4. HUMAN-COMPUTER INTERACTION • GUIs • Mouse input • Direct manipulation • MOBILE COMPUTING • Pen-based input • Handwriting recognition • Email, SMS messaging • Two-way pagers, mobile phones • HUMAN FACTORS • Office automation • Word processing • Document management Text Entry Research - Timeline Lots Research Activity Little 1960 1970 1980 1990 2000 Year

  5. Keyboards

  6. Virtual vs Physical Keyboards • Virtual keyboards • Aka “soft keyboards” or “on-screen keyboards” • Similar to clicking buttons in a GUI • Typically used with a stylus (but also with eye/head trackers and other input mechanisms) • Physical keyboards • Desktop qwerty, miniature qwerty, mobile phone keypad, 5-button pager, 3-key date stamp, 1-key input, etc. • Design Issues • Key layout, key size, key shape, number of keys, activation force, disambiguation, language modeling, word prediction, etc.

  7. Keyboard Layouts – A Quick Tour Qwerty

  8. Dvorak

  9. Fitaly

  10. Opti

  11. Qwerty variations

  12. ABC

  13. Half Qwerty

  14. Phone

  15. Five-key pager

  16. Hello ther _abcdefghijklmnopqrstuvwxyz e   Select Three-key date stamp

  17. One-key input

  18. More Ambiguity Continuum Less Number-of-keys Continuum Number of Keys

  19. ? R U N N E R Ambiguity • Ambiguity occurs if there are fewer keys than symbols in the language • Disambiguation is needed to select the intended letter from the possibilities • Phone keypad is a typical example Or, is it SUMMER, is it STONES ? Demo: java Decode d1-wordfreq-phoneks.txt 10

  20. Word Prediction • Basic problem… • Given some amount of preceding text, predict subsequent text • Design issues • Dynamic vs. static language model • Word-level or phrase-level prediction • Size of candidate word list • Candidate word selection • Improving performance Demo: java WordPredict d1-wordfreq.txt 10

  21. Disambiguation + Word Prediction Demo: java PhoneKeypad d1-wordfreq-phoneks.txt

  22. Evaluation

  23. Quick Example Qwerty Opti • Is Opti as fast as Qwerty?

  24. Opti is faster, but only after about 4 hours of practice Opti vs. Qwerty

  25. Evaluation • Research questions • Typically, something like… • Is design A as fast/accurate as design B? • Research questions come together as… • Independent variables, and • Dependent variables

  26. Independent Variables • These are the factors and levels in your experiment • Examples

  27. Opti vs. Qwerty • Two Independent variables • Keyboard layout with 2 levels: Opti, Qwerty • Session with 20 levels: 1, 2, 3, … 20 • Referred to as a 2 x 20 factorial design • The 40 test conditions were given to all participants, thus we have a 2 x 20 within-subject design (i.e., each subject received all 40 test conditions) • Note: within-subject design = repeated measures design (cf. between-subjects design)

  28. Dependent Variables • These are the behaviours you measure • Examples

  29. Speed as a Dependent Variable • Relatively straight forward to measure • Example... 1 2 3 41234567890123456789012345678901234567890123the quick brown fox jumps over the lazy dog t = 60 seconds = 1 minute Number of characters = 43 Number of words = 43 / 5 = 8.6 Speed = 8.6 / 1 = 8.6 wpm Note: Definition of a word: “five characters, including spaces, punctuation, etc”

  30. Accuracy as a Dependent Variable • A bit trickier to measure • Example... • How many errors? • What are the errors? • What is the error rate (%)? Presented text 2 (gee, that was easy) the quick brown fox the quixck brwn fox • An “x” was inserted • An “o” was omitted Transcribed text ER = 2 / 19 = 0.105 = 10.5% Easy? Try this one (next slide)

  31. quic--klyqu-cehklyquic-klyqucehklyqui-cklyqucehklyqu-icklyqucehklyquic--klyqu-cehklyquic-klyqucehklyqui-cklyqucehklyqu-icklyqucehkly Hmm, let’s see Accuracy is a Bit Tricky • How many errors? • What are the errors? • What is the error rate? Presented text 3 (that was a bit tricky) quickly qucehkly Transcribed text ER = 3 / 8.25 = 0.364 = 36.4%

  32. Error rate = 36.4% KSPC = 10 / 8 = 1.2 Note: KSPC = keystrokes per character Accuracy is a Bit Tricky (2) Presented text quicklyqxucehkly qucehkly Input stream Transcribed text

  33. Keystrokes Per Character (KSPC) • KSPC is useful both as a characteristic of text entry methods and as dependent variable in evaluations of text entry methods • KSPC as a characteristic • The average number of keystrokes to produce each character of text for a given language and entry method; e.g., • KSPC  1.00 for the Qwerty keyboard • KSPC  2.02 for multitap on a mobile phone • KSPC as a dependent variable • A behavioural measure of the keystroke activity in entering text; e.g., (see previous slide)

  34. KSPC Characteristics KSPC > 1 KSPC < 1

  35. Case Study

  36. Hello ther _abcdefghijklmnopqrstuvwxyz e   Select Three-key Text Entry • The basic idea… Edit buffer “Virtual” keyboard Physical keys

  37. Design Issues • Cursor modes • “Persistent” = stays put after each entry • “Snap to home” = snap to SPACE after each entry • SPACE position • Left, middle, right, etc. • Letter order • Alphabetical • By probability of letters, digrams, etc. • Fluctuating (next slide)

  38. FOCL • FOCL = fluctuating optimal character layout • Letters rearranged after each entry • “Highly probable next characters” positioned closest to cursor • Advantage: fewer keystrokes • Disadvantage: increased cognitive load

  39. FOCL “Level 1” and “Level 2”

  40. Three-Key Method Comparisons The next step…

  41. User Testing Methods #2 and #6 chosen for user testing

  42. Participants and Apparatus • Participants • 10 paid volunteers (8 male, 2 female) • Ages 20 to 49 (mean = 30.1, sd = 8.5) • 3+ hours of computer usage per day • Apparatus (standard PC) • Input • Keyboard keys (configurable) • Most used “z” = left arrow, “x” = right arrow, “Enter” = Select • Output • CRT display (next slide)

  43. Display - Method #2 Transcribed text Presented text Virtual keyboard

  44. Display - Method #6

  45. Typamatic Cursor Keys • Auto-repeat, or typamatic, cursor key behaviour possible • Used at discretion of participant • Spec’s • Delay = 176 ms • Repeat rate = 31.2 char/second

  46. Procedure and Design • One-hour session per participant • About 25 minutes of text entry for each condition • Order of conditions counterbalanced • Instructions: Enter text phrases as quickly and accurately as possible. Ignore mistakes. Continue in the event of a error. • A few practice phrases, then data collection • Post-test questionnaire

  47. Speed • 9-10 wpm • Difference not statistically significant

  48. Comparisons

  49. Accuracy • Difference not statistically significant

  50. KSPC Characteristic (given earlier)

More Related