1. Typewriter Keyboards via Simulated Annealing Reporter: En-ping Su Date: 3.2 2006

2. Outline Traditional Keyboard Design Keyboard Design as Combinatorial Optimization Keyboard Design via Simulated Annealing Results and Conclusions

3. Traditional Keyboard Design “ QWERTY ” keyboard It was designed to slow down typists. These archaic design decisions have brought about several unhappy consequences.

4. Traditional Keyboard Design The defects of “ QWERTY ” keyboard QWERTY distributes typing unequally among the hands, favoring the left hand over the right. QWERTY overloads the weaker fingers. QWERTY use the home (middle) row of keys less than one-third of the time. QWERTY seems to ignore the fact that alternate hand typing of common letter pairs is by far faster than same hand typing them.

5. Traditional Keyboard Design Figure 1. The famous QWERTY keyboard Home row

6. Traditional Keyboard Design Many alternatives to QWERTY have been proposed over the years “ Combinational Keyboard ” by Nelson in 1920. “ Orthographic Keyboard ” by Gilbert in 1930. “ Dvorak Simplified Keyboard ” by August Dvorak in 1932.

7. Traditional Keyboard Design Dvorak Simplified Keyboard (D.S.K) A keyboard designed around a statistical analysis of common English letter pairs. A keyboard that would decrease the likelihood of error by making typing more “ natural ” and less awkward, by reducing finger motions from row to row.

8. Traditional Keyboard Design A keyboard that would maximize the use of the “ home ” row and the fastest sorts of keystrokes. A keyboard the would give the strong right hand more work to do. A keyboard that is easier to learn, less subject to error, and less tiring.

9. Traditional Keyboard Design Figure 2. Dvorak ’ s keyboard

10. Traditional Keyboard Design Kinkead ’ s method 2 2 :the relative frequency of every letter pair, (α, β), for English. 2 :keying times between positions on the standard three-row keyboard.

11. Keyboard Design as Combinatorial Optimization The problem of optimal keyboard design is a problem of combinatorial optimization. It ’ s also a NP-complete problem. ex: Traveling Salesman Problem. Many algorithms do exist for finding nearly optimal solutions to them. Repeatedly generate solutions Greedy improvement it may be local optimal not global optimal

12. Keyboard Design via Simulated Annealing In 1983, Kirkpatrick, et al. issue Simulated annealing (SA) A variable, T ( “ temperature ” ) The probability function, which includes the variable T. A “ cooling schedule, ” that determines how rapidly T is decreased.

13. Keyboard Design via Simulated Annealing

14. Results and Conclusions Figure 3. Our best keyboard.

15. Results and Conclusions CostR:L %Top %Home %Bottom % QWERTY154243:57523216 Dvorak150256:4487022 SA142852:48384319 Table 1. The comparisons of three keyboards

16. Results and Conclusions Table 2. Alternate hand typing of the top 10 English letter pairs

17. Results and Conclusions The most frequent letters in English — E, T, A, O, I, N — are mostly typed by the strong index and middle fingers. Letters that are rarely used — W, X, Q, V — are relegated to the bottom row or are typed by the weaker fingers.