The HARPY Speech Recognition System
A 1976 Carnegie-Mellon University computer science thesis by Bruce Lowerre, distributed through the Defense Technical Information Center, describing the HARPY speech recognition system for researchers in computing and speech. The three pages are typed diagrams of grammar networks: circles joined by arrows, with words or phonetic symbols inside, stacked in tiered layouts that show how alternative paths branch and merge. A designer could draw on their clean node-and-arrow geometry, the tidy hierarchy of levels, and the rows of small circled labels as a template for flowchart or network graphics.
