Properties of Real World Digital Logic Diagrams

by

Christine Alvarado and Michael Lazzareschi

Summary

Pure sketch recognition is difficult. To get around this fact (which should be painfully obvious to us all by now), many designers put restrictions on how the user can draw. This becomes a balancing act between making the recognition easier and providing a natural drawing experience. These restrictions are often done so to make the developer's life easy, and there is no attempt to understand natural drawing behavior.

The authors wanted to observe the natural drawing behavior of students. They focused primarily on three aspects: stroke order, strokes timing, and stroke number. In their study students were given a tablet to use for their digital design course. They were instructed to use this tablet in lieu of paper. Thirteen students participated, 98 diagrams were collected and each one was labeled by hand. The authors looked at the temporally contiguous nature of the strokes, and how consistent each student was. 19% of all the symbols drawn by the students were done with non-consecutive strokes. These strokes were often corrections. Also noted was how long the students paused between strokes overlaps greatly with how long they pause between strokes in the same shapes, thus this pause is not a clear indicator of when the user is drawing a new symbol. The researchers observed that many students did not draw symbols consistently with the same number of strokes. However non consistent students were consistently non consistent, and consistent students were consistently consistent. If someone can say the prior sentence five times real fast I'll give them a cookie. Few properties were consistent across all students.

Discussion

Judging from the chart the stroke timing overlap is minimal, they do not overlap greatly as the author states. Is it perfect? No, but I think categorizing it as great overlap is off. Also the statement of focusing on digital logic diagrams because little work as done in the domain seems strange to me. Almost every sketch recognition paper I have ever read uses this as an example. The fact that drawing mechanics seem to not be similar across users bodes well for my semester project.

Citation

Christine Alvarado and Michael Lazzareschi. Properties of Real World Digital Logic Diagrams. 1st International Workshop on Pen-based Learning Technologies (PLT) 2007.