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Purpose• Develop a keyboard optimization
algorithm.
– Utilize Fitts’s Law and other aspects of the Card-Moran-Newell (CMN) model of the human processor.
• Demonstrate that neither the QWERTY nor the Dvorak keyboard layout is an optimal configuration of the keys on the three-row keyboard.
– These layouts can be improved upon using quantitative methods.
History: QWERTY
• Old typewriters used typebars and had an “invisible” printing point, leading to frequent jams.
• There is speculation that they intentionally placed all the letters of the word “typewriter” in the top row for quick and easy demonstration.
History: Dvorak
• In the 1930’s, August Dvorak and William Dealey developed and patented a new layout, known as the Dvorak Simplified Keyboard (DSK).
• Designed to improve typing efficiency and user comfort.
• Reasoning for layout was strictly qualitative.
Methods: Scale Issues
Why Not Examine Every Possible Permutation?
At one keyboard per second, that’s 8.41*1024 years.
The sun will burn out after 5*109 of them.
3210*65.2!303030 P
Methods: Keyboard Population
• Rather than look at entire keyboards, examine the influence of specific keys in specific locations.
• There are only 30*30 = 900 key-position pairs.
• We can randomly populate a large number of keyboards, then see how certain keys in certain positions influence their performance.
Methods: Scoring Keyboards
• First, need a figure of merit for keyboard performance:– Compile a large text file
and calculate how long it would take an average human to type that entire file using that keyboard.
– These figures are derived from the CMN model and Fitts’s Law.
Methods: Applying CMN
• Used Fitts’s Law to determine how long it would take a typist to move a finger from one key to another.
• Determined inter-row and inter-finger transition times.
• From this data, could determine the time to transition from any finger in any position to any other.
• See paper for quantitative details.
Methods: Compiling a Text Sample
• ~500KB of raw text
• 80,720 Characters
• Sources:– Popular Novels– Famous Speeches– TV Transcripts– Rap Lyrics
Methods: Algorithmic Flow
• Simulate 90,000 keyboards.• Expect to see each key-
position combination 3,000 times.
• Enough data to determine the best possible key-position combination.
• “Lock-In” that key.• Repeat, simulating only the
remaining 29 keys.• Continue until entire
keyboard populated.
Conclusions
• Our method was successful.• While DSK is a quantifiable
improvement over QWERTY, our model is more efficient than both.
• Extensions: Software’s robustness allows for keyboards customized to users or industries.