{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,8,5]],"date-time":"2025-08-05T13:01:01Z","timestamp":1754398861807,"version":"3.41.0"},"reference-count":57,"publisher":"Association for Computing Machinery (ACM)","issue":"1","license":[{"start":{"date-parts":[[2023,2,28]],"date-time":"2023-02-28T00:00:00Z","timestamp":1677542400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["dl.acm.org"],"crossmark-restriction":true},"short-container-title":["ACM Trans. Comput.-Hum. Interact."],"published-print":{"date-parts":[[2023,2,28]]},"abstract":"<jats:p>\n            Improving keystroke savings is a long-term goal of text input research. We present a study into the design space of an abbreviated style of text input called\n            <jats:italic>C-PAK<\/jats:italic>\n            (Correcting and completing variable-length Prefix-based Abbreviated Keystrokes) for text entry on mobile devices. Given a variable length and potentially inaccurate input string (e.g., \u201cli\u00a0g\u00a0t\u00a0m\u201d), C-PAK aims to expand it into a complete phrase (e.g., \u201clooks good to me\u201d). We develop a C-PAK prototype keyboard,\n            <jats:italic>PhraseWriter<\/jats:italic>\n            , based on a current state-of-the-art mobile keyboard consisting of 1.3 million\n            <jats:italic>n<\/jats:italic>\n            -grams and 164,000 words. Using computational simulations on a large dataset of realistic input text, we found that, in comparison to conventional single-word suggestions, PhraseWriter improves the maximum keystroke savings rate by 6.7% (from 46.3% to 49.4,), reduces the word error rate by 14.7%, and is particularly advantageous for common phrases. We conducted a lab study of novice user behavior and performance which found that users could quickly utilize the C-PAK style abbreviations implemented in PhraseWriter, achieving a higher keystroke savings rate than forward suggestions (25% vs. 16%). Furthermore, they intuitively and successfully abbreviated more with common phrases. However, users had a lower overall text entry rate due to their limited experience with the system (28.5 words per minute vs. 37.7). We outline future technical directions to improve C-PAK over the PhraseWriter baseline, and further opportunities to study the perceptual, cognitive, and physical action trade-offs that underlie the learning curve of C-PAK systems.\n          <\/jats:p>","DOI":"10.1145\/3544101","type":"journal-article","created":{"date-parts":[[2022,7,18]],"date-time":"2022-07-18T12:21:11Z","timestamp":1658146871000},"page":"1-35","update-policy":"https:\/\/doi.org\/10.1145\/crossmark-policy","source":"Crossref","is-referenced-by-count":7,"title":["C-PAK: Correcting and Completing Variable-Length Prefix-Based Abbreviated Keystrokes"],"prefix":"10.1145","volume":"30","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0877-5727","authenticated-orcid":false,"given":"Tianshi","family":"Li","sequence":"first","affiliation":[{"name":"Carnegie Mellon University, Pittsburgh, PA, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6340-0568","authenticated-orcid":false,"given":"Philip","family":"Quinn","sequence":"additional","affiliation":[{"name":"Google, CA, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0752-2090","authenticated-orcid":false,"given":"Shumin","family":"Zhai","sequence":"additional","affiliation":[{"name":"Google, CA, USA"}]}],"member":"320","published-online":{"date-parts":[[2023,3,7]]},"reference":[{"key":"e_1_3_2_2_2","doi-asserted-by":"publisher","DOI":"10.18653\/v1\/2021.acl-long.514"},{"key":"e_1_3_2_3_2","article-title":"WiseType: A tablet keyboard with color-coded visualization and various editing options for error correction","author":"Alharbi Ohoud","year":"2019","unstructured":"Ohoud Alharbi, Ahmed Sabbir Arif, Wolfgang Stuerzlinger, Mark D. 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