Browsing by Author "Datta, Sanjeev"

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    Implementation of a Perfect Hash Function Scheme
    Datta, Sanjeev; Fox, Edward A. (Department of Computer Science, Virginia Polytechnic Institute & State University, 1989-03-01)
    This report surveys the recent development in computing perfect hash functions, and in particular, closely examines an algorithm proposed by Thomas Sager. An implementation of that algorithm in C has been done to demonstrate and verify the behavior of the algorithm for various settings of parameters.
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    A More Cost Effective Algorithm for Finding Perfect Hash Functions
    Fox, Edward A.; Chen, Qi-Fan; Heath, Lenwood S.; Datta, Sanjeev (Department of Computer Science, Virginia Polytechnic Institute & State University, 1988-09-01)
    As the use of knowledge-based systems increases, there will be a growing need for efficient artificial intelligence systems and methods to access large lexicons. In the Composite Document Expert/extended/effective Retrieval (CODER) system we have, in order to provide rapid access to data items on CD-ROM's and to terms in a lexicon built from machine readable dictionaries, investigated the construction of perfect hashing functions. We have considered algorithms reported earlier in the literature, have made numerous enhancements to them, have developed new algorithms, and here report on some of our results. This paper covers an $O(n^3)$ algorithm that has been applied to building hashing functions for a collection of 69806 words on a CD-ROM. Most recently we have developed a much better algorithm and have succeeded in finding a perfect hash function for a set of 5000 words taken from the Collins English Dictionary.