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Faster Deterministic Dictionaries

Rasmus Pagh
1999 BRICS Report Series  
A by-product of the result<br />is a lookup time vs insertion time trade-off for dynamic dictionaries, which<br />is optimal for a certain class of deterministic hashing schemes.  ...  In contrast, the best previous<br />deterministic algorithm for constructing such a dictionary with n elements<br />runs in time O(n^(1+epsilon)) for epsilon > 0.  ...  Acknowledgments: The author would like to thank Gerth Stølting Brodal, Gudmund Skovbjerg Frandsen, Peter Bro Miltersen and Theis Rauhe for helpful discussions in connection with this work.  ... 
doi:10.7146/brics.v6i48.20118 fatcat:ew4lq3zrhngdbl7roohypfpx4e

Super-Linear Indices for Approximate Dictionary Searching [chapter]

Leonid Boytsov
2012 Lecture Notes in Computer Science  
These data are indexed using a perfect hash function computed for a set of residual dictionary strings [2].  ...  A straightforward implementation that creates a hash index directly over residual strings (obtained by deletions from dictionary words) is not space efficient.  ...  I am very grateful to my wife Anna for editorial assistance.  ... 
doi:10.1007/978-3-642-32153-5_12 fatcat:52enei4um5dp5hd55lstjviywu

HASH SEARCH ORGANIZATION IN E-DICTIONARIES USING BLOCK CIPHERS

Olexander MARKOVSKYI, Inna Humeniuk, Olha Shevchenko
2020 Information, Computing and Intelligent systems  
The article is devoted to the problem of developing high-speed electronic dictionaries for systems computer translation.  ...  The method of organizing a high-speed electronic dictionary based on an ideal hash addressing, where the cryptographic cipher block acts as a hash transformation is proposed.  ...  Another feature of hashing is that the result of a hash function for two close keys will be different.  ... 
doi:10.20535/2708-4930.1.2020.216053 fatcat:2ocrw6yamfh4pcijjhg3wsu4ea

Maintaining External Memory Efficient Hash Tables [chapter]

Philipp Woelfel
2006 Lecture Notes in Computer Science  
We achieve 100% utilization in the static version (and thus a minimal perfect hash function) and 1 − utilization in the dynamic case.  ...  We describe a dynamic version of Pagh's hashing scheme achieving 100% table utilization but requiring (2 + ) · n log n space for the hash function encoding as well as (3 + ) · n log n space for the auxiliary  ...  Acknowledgment The author is grateful to Martin Dietzfelbinger and Rasmus Pagh for enlightening discussions on the subject of the paper. The anonymous referees provided very helpful comments.  ... 
doi:10.1007/11830924_46 fatcat:l6xkns6iwvcydmkyg2apw3sl6m

A new approach to hash function construction for textual data: A comparison

Vaclav Skala, Radek Petruska
2014 2014 4th World Congress on Information and Communication Technologies (WICT 2014)  
A comparison of new technique for hash function construction is presented in the paper without need of division operation.  ...  State of the art in hashing of textual data is given (the perfect hashing techniques are not included).  ...  Thanks belong also to anonymous reviewers for their critical comments that helped to improve this manuscript significantly. EkoTox database data courtesy of Dr.Pavel Pavliček and Vilém Čermák.  ... 
doi:10.1109/wict.2014.7077299 fatcat:76yiyrotrvfnbpx22pmyetl7em

Fast hashing of variable-length text strings

Peter K. Pearson
1990 Communications of the ACM  
So the nonuniform distribution of the additive hashing function does not necessarily confer a large performance penalty.  ...  Perfect Hashing A hashing function is perfect, with respect to some list of words, if it maps the words in the list onto distinct values, that is, with no collisions.  ...  direct commercial advantage, the ACM copyright notice and the title of the publication and its date appear, and notice is given that copying is by permission of the Association for Computing Machinery  ... 
doi:10.1145/78973.78978 fatcat:6zv2dkkrrnfgnixwiwjhv7mgbq

Improved Bounds for Dictionary Look-up with One Error

Gerth Stølting Brodal, Srinivasan Venkatesh
1999 BRICS Report Series  
This generalizes and improves the <br />previous bounds of Yao and Yao for the problem in the bit probe<br />model.</p><p>Keywords: Data Structures, Dictionaries, Hashing, Hamming Distance</p><p> </p>  ...  <p>Given a dictionary S of n binary strings each of length m,<br />we consider the problem of designing a data structure for S that<br />supports d-queries; given a binary query string q of length m, a  ...  A family H is an ( , n, k)-family of perfect hash functions if for all S ⊆ {0, 1, . . . , − 1} of size n, there is an h ∈ H that is perfect for S.  ... 
doi:10.7146/brics.v6i50.20120 fatcat:rl24hpxmlnegxohyqqdxsjwzuq

Cuckoo hashing

Rasmus Pagh, Flemming Friche Rodler
2004 Journal of Algorithms  
We present a simple dictionary with worst case constant lookup time, equaling the theoretical performance of the classic dynamic perfect hashing scheme of Dietzfelbinger et al. [SIAM J.  ...  An implementation inspired by our algorithm, but using weaker hash functions, is found to be quite practical.  ...  Acknowledgments The authors thank Andrei Broder, Martin Dietzfelbinger, Rolf Fagerberg, Peter Sanders, John Tromp, and Berthold Vöcking for useful comments and discussions on this paper and CUCKOO HASHING  ... 
doi:10.1016/j.jalgor.2003.12.002 fatcat:3yksbb2ffzgl7jgbnvwdkox7gq

Perfect hashing

Zbigniew J. Czech, George Havas, Bohdan S. Majewski
1997 Theoretical Computer Science  
Any perfect hash , . function can be perfect for at most (i )" (r) subsets.  ...  Next for each Lj, i E I, a perfect hash function is constructed.  ... 
doi:10.1016/s0304-3975(96)00146-6 fatcat:htaph24frffzjevl2q6kxz467e

Finite automata for compact representation of tuple dictionaries

Jan Daciuk, Gertjan van Noord
2004 Theoretical Computer Science  
A technique for compact representation of tuple dictionaries is presented. The technique can be seen as an application and extension of perfect hashing by means of ÿnite-state automata.  ...  This data structure is motivated by practical applications in speech and language processing, in which very large instances of tuple dictionaries are used to represent language models.  ...  Acknowledgements This research was carried out within the framework of the PIONIER Project Algorithms for Linguistic Processing, funded by NWO (Dutch Organization for Scientiÿc Research) and the University  ... 
doi:10.1016/j.tcs.2003.10.003 fatcat:eugmvonu75hlxozxikbbltesgy

Simple, compact and robust approximate string dictionary [article]

Ibrahim Chegrane, Djamal Belazzougui
2014 arXiv   pre-print
Finally our data structure is simple to implement as it only uses basic techniques from the literature, mainly hashing (linear probing and hash signatures) and succinct data structures (bitvectors supporting  ...  We present a practical implementation of the data structure we recently proposed and which works only for one error. We extend the scheme to 2≤ k<m.  ...  Acknowledgments We thank Nacera Bensaou for her encouragement and fruitful discussions at the early stages of this work. We thank Simon Puglisi for his many useful comments and remarks.  ... 
arXiv:1312.4678v2 fatcat:iszmv4sgk5bozmh7g5hryxnlhy

A high-speed and large-scale dictionary matching engine for Information Extraction systems

Kanak Agarwal, Raphael Polig
2013 2013 IEEE 24th International Conference on Application-Specific Systems, Architectures and Processors  
modified hashing against the standard hashing which uses the same RAM (2K RAM slots for each 1000 word dictionary) but uses a single large RAM to store each dictionary Chain hashing stores all dictionaries  ...  and the RAM Hash Collisions  Expected number of hash collisions for hashing L D words in L M RAM slots -Assuming perfect uniform random distribution  Hash collisions can be reduced by increasing RAM  ...  Differentiation from Existing Software Hash Collision Reduction Solutions -Expected number of collisions should be zero -Memory overhead should be limited including overhead due to multi-port memory (which  ... 
doi:10.1109/asap.2013.6567551 dblp:conf/asap/AgarwalP13 fatcat:rdbsui7orvdabhi63pers5pmzm

Build Electronic Arabic Lexicon [article]

Nidhal El-Abbadi, Ahmed Nidhal Khdhair, Adel Al-Nasrawi
2013 arXiv   pre-print
The paper also presents new way to build an electronic Arabic lexicon by using a hash function that converts each word (as input) to correspond a unique integer number (as output), these integer numbers  ...  There exist methods for maintaining a perfect hash function under insertions of keys, known as dynamic perfect hashing.  ...  • Perfect Hashing: if all of the keys that will be used are known ahead of time, and there are no more keys that can fit the hash table, perfect hashing can be used to create a perfect hash table  ... 
arXiv:1311.6045v1 fatcat:c35ziyuifnfafd5ccrhz7w3vqy

Hash-bucket search: A fast technique for searching an english spelling dictionary

Douglas Comer, Vincent Y. Shen
1982 Software, Practice & Experience  
This paper presents the hash-binary method for searching a static table and applies It to searching an English spelling dictionary.  ...  Experiments with a sample dictionary verify the results. We also present extensions to account for skewed frequencies of access as well as methods for testing alternative hashing func-tIons.  ...  Sprugno1 i proposes severaI perfect hash i ng funct i ons [SPRU77] , but they all require a large amount of space and preprocessing time.  ... 
doi:10.1002/spe.4380120708 fatcat:5ma26dzqpje2nbw2vwfzyacdsu

CHRONOS

Kaouthar Blibech, Alban Gabillon
2005 Proceedings of the 2005 workshop on Secure web services - SWS '05  
More recently, Maniatis and Baker [10][11] [12] have proposed an authenticated append only dictionary based on perfect skip lists.  ...  Moreover this dictionary allows comparing the relative order of elements. Such a dictionary could be used for timestamping purposes.  ...  f is the commutative hash function.  ... 
doi:10.1145/1103022.1103037 dblp:conf/sws/BlibechG05 fatcat:6zziiiyr5vatbi2oyksnhdfex4
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