Approximation algorithms for NP-hard problems
Approximation algorithms for NP-hard problems
STOC '97 Proceedings of the twenty-ninth annual ACM symposium on Theory of computing
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SIAM Journal on Computing
Approximation algorithms
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AUIC '02 Proceedings of the Third Australasian conference on User interfaces - Volume 7
Computers and Intractability: A Guide to the Theory of NP-Completeness
Computers and Intractability: A Guide to the Theory of NP-Completeness
Text input disambiguation supported on a hierarchical user model
Proceedings of the 2005 joint conference on Smart objects and ambient intelligence: innovative context-aware services: usages and technologies
The single-finger keyboard layout problem
Computers and Operations Research
Automatic and self-paced scanning for alternative text entry
Telehealth/AT '08 Proceedings of the IASTED International Conference on Telehealth/Assistive Technologies
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ICCHP'10 Proceedings of the 12th international conference on Computers helping people with special needs
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We study the problem of placing symbols of an alphabet onto the minimum number of keys of a small keyboard so that any word of a given dictionary can be recognized univoquely only by looking at the corresponding sequence of keys. This problem is motivated by the design of small keyboards for mobile devices. We show that the problem is hard in general, and NP-complete even if we only wish to decide whether two keys are sufficient. We also consider two variants of the problem. In the first one, symbols on a key must be contiguous in an ordered alphabet. In the second variant, a well-chosen measure of ambiguity in the recognition of the words is minimized given the number of keys. Hardness and approximability results are given.