Results 1 - 10 of 106

On minimizing deterministic tree automata

by L G W A Cleophas , D G Kourie , T Strauss , B W Watson
"... Abstract. We present two algorithms for minimizing deterministic frontier-to-root tree automata (dfrtas) and compare them with their string counterparts. The presentation is incremental, starting out from definitions of minimality of automata and state equivalence, in the style of earlier algorithm ..."
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Abstract. We present two algorithms for minimizing deterministic frontier-to-root tree automata (dfrtas) and compare them with their string counterparts. The presentation is incremental, starting out from definitions of minimality of automata and state equivalence, in the style of earlier

Backward and forward bisimulation minimisation of tree automata

by Johanna Högberg, Andreas Maletti, Jonathan May , 2007
"... Abstract. We improve an existing bisimulation minimisation algorithm for tree automata by introducing backward and forward bisimulations and developing minimisation algorithms for them. Minimisation via forward bisimulation is also effective for deterministic automata and faster than the previous al ..."
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Abstract. We improve an existing bisimulation minimisation algorithm for tree automata by introducing backward and forward bisimulations and developing minimisation algorithms for them. Minimisation via forward bisimulation is also effective for deterministic automata and faster than the previous

Bisimulation Minimisation for Weighted Tree Automata

by Johanna Högberg, Andreas Maletti, Jonathan May , 2007
"... We generalise existing forward and backward bisimulation minimisation algorithms for tree automata to weighted tree automata. The obtained algorithms work for all semirings and retain the time complexity of their unweighted variants for all additively cancellative semirings. On all other semirings t ..."
Abstract - Cited by 9 (6 self) - Add to MetaCart
We generalise existing forward and backward bisimulation minimisation algorithms for tree automata to weighted tree automata. The obtained algorithms work for all semirings and retain the time complexity of their unweighted variants for all additively cancellative semirings. On all other semirings

Hyper-minimisation of deterministic weighted finite automata . . .

by Andreas.Maletti , Daniel Quernheim
"... Hyper-minimisation of deterministic finite automata is a recently introduced state reduction technique that allows a finite change in the recognised language. A generalisation of this lossy compression method to the weighted setting over semifields is presented, which allows the recognised formal po ..."
Abstract - Cited by 1 (0 self) - Add to MetaCart
power series to differ for finitely many input strings. First, the structure of hyper-minimal deterministic weighted finite automata is characterised in a similar way as in classical weighted minimisation and unweighted hyper-minimisation. Second, an efficient minimisation algorithm, which runs in time

Minimizing Deterministic Weighted Tree Automata

by Andreas Maletti , 2008
"... The problem of efficiently minimizing deterministic weighted tree automata (wta) is investigated. Such automata have found promising applications as language models in Natural Language Processing. A polynomial-time algorithm is presented that given a deterministic wta over a commutative semifield, o ..."
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The problem of efficiently minimizing deterministic weighted tree automata (wta) is investigated. Such automata have found promising applications as language models in Natural Language Processing. A polynomial-time algorithm is presented that given a deterministic wta over a commutative semifield

An implementation of deterministic tree automata minimization

by Rafael C. Carrasco, Jan Daciuk, Mikel L. Forcada
"... Abstract. A frontier-to-root deterministic finite-state tree automaton (DTA) can be used as a compact data structure to store collections of unranked ordered trees. DTAs are usually sparser than string automata, as most transitions are undefined and therefore, special care must be taken in order to ..."
Abstract - Cited by 4 (0 self) - Add to MetaCart
Abstract. A frontier-to-root deterministic finite-state tree automaton (DTA) can be used as a compact data structure to store collections of unranked ordered trees. DTAs are usually sparser than string automata, as most transitions are undefined and therefore, special care must be taken in order

Bisimulation Minimisation of Weighted Automata on Unranked Trees

by J. Högberg, A. Maletti, H. Vogler , 2008
"... Two examples of automata-theoretic models for the validation of xml documents against user-de ned schema are the stepwise unranked tree automaton (suta) and the parallel unranked tree automaton (puta). By adding a weight, taken from some semiring, to every transition we generalise these two qualitat ..."
Abstract - Cited by 5 (1 self) - Add to MetaCart
Two examples of automata-theoretic models for the validation of xml documents against user-de ned schema are the stepwise unranked tree automaton (suta) and the parallel unranked tree automaton (puta). By adding a weight, taken from some semiring, to every transition we generalise these two

Hyper-Minimization for Deterministic Tree Automata

by Artur Jez, Andreas Maletti , 2012
"... Hyper-minimization aims to reduce the size of the representation of a language beyond the limits imposed by classical minimization. To this end, the hyper-minimal representation can represent a language that has a finite difference to the original language. The first hyperminimization algorithm is ..."
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is presented for (bottom-up) deterministic tree automata, which represent the recognizable tree languages. It runs in time O(ℓmn), where ℓ is the maximal rank of the input symbols, m is the number of transitions, and n is the number of states of the input tree automaton.

Minimizing Deterministic Weighted Tree Automata

by unknown authors
"... The problem of efficiently minimizing deterministic weighted tree automata (wta) is investigated. Such automata have found applications as language models in Natural Language Processing. A polynomial-time algorithm is presented that given a deterministic wta over a commutative semifield constructs a ..."
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The problem of efficiently minimizing deterministic weighted tree automata (wta) is investigated. Such automata have found applications as language models in Natural Language Processing. A polynomial-time algorithm is presented that given a deterministic wta over a commutative semifield constructs

A Taxonomy of Algorithms for Constructing Minimal Acyclic Deterministic Finite Automata

by Bruce Watson - Proc. Workshop on Implementing Automata , 1999
"... this paper, we present a taxonomy of algorithms for constructing minimal acyclic deterministic finite automata (MADFAs). MADFAs represent finite languages and are therefore useful in applications such as storing words for spellchecking, computer and biological virus searching, text indexing and XML ..."
Abstract - Cited by 7 (1 self) - Add to MetaCart
this paper, we present a taxonomy of algorithms for constructing minimal acyclic deterministic finite automata (MADFAs). MADFAs represent finite languages and are therefore useful in applications such as storing words for spellchecking, computer and biological virus searching, text indexing and XML
Results 1 - 10 of 106