Research Article
PaperCAD: A System for Interrogating CAD Drawings Using Small Mobile Computing Devices Combined with Interactive Paper
Table 4
Interpretation of double-headed arrows.
| Event | Correct | Incorrect |
| Correctly interpreted | 233 | | Did not complete before timeout (U) | | 13 | Did not pause before writing label (U) | | 1 | Missing one arrowhead (U) | | 1 | Not perpendicular to the datums (U) | | 1 | Extension lines not parallel (U) | | 3 | Did not draw extension line (U) | | 11 | Did not realize that previously drawn extension line was not valid (U) | | 2 | Datums not perpendicular (U) | | 5 | Not recognized (S) | | 1 | Extension line misinterpreted (S) | | 3 | Misinterpreted as a single arrow (S) | | 15 | Misinterpreted as missing a datum (S) | | 1 | Misinterpreted as not perpendicular to datums (S) | | 14 | Total | 233 | 71 |
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U: user error; S: system error.
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