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By Dominika Polak based on TITLE: „Natural Language Processing in Prolog”

FINITE-STATE TECHNIQUES. By Dominika Polak based on TITLE: „Natural Language Processing in Prolog” AUTHOR: G.Gazdar C.Mellish EDITION: Addison Wesley 1989. OUTLINE. Finite-State Transitional Network / Finite-State Automaton / Diagram of FSTN

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By Dominika Polak based on TITLE: „Natural Language Processing in Prolog”

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  1. FINITE-STATE TECHNIQUES By Dominika Polak based on TITLE: „Natural Language Processing in Prolog” AUTHOR: G.Gazdar C.Mellish EDITION: Addison Wesley 1989

  2. OUTLINE • Finite-State Transitional Network / Finite-State Automaton / • Diagram of FSTN • Function of FSTN: generation / recognition • Non-deterministic FSTN • FSTN with „jump”arc • Symbols from SAMPA • Abbreviations • Application

  3. Finite-State Automaton A device which has a finite number of states over which we traverse by means of arcs. Finite-State Transition Network An ilustration (with labels) of finite state automation to: - recognize elements of lg. - generate elements of lg. FINITE-STATE TECHNIQUES

  4. DIAGRAM OF FSTN: Y B E 2 3 ! 1 4 5 2 3 E L 1 –INITIAL STATE I 2 –FINAL STATE B,Y,E,L,I,! - LABELS

  5. ( Creatingallpossibletransitions ) FIRST FUNCTION OF FSTN – GENERATION f.e: Question:How to get from Kurpińskiego to UAM by tram ? Description of the net: Name:The way by tram Initial state:1 Final state:4 1-(From 1 to 4 by 12)-1-4 (12) 2- 1-2 (14) 2-4 (10) 3- 1-2 (14) 2-3 (14) 3-4 (6) 4- 1-2 ( D) 2-3 (14) 3-4 (6) 5- 1-2 (D) 2-4 (10) 10 14 D 14 6 2 4 1 3 Kurp. PKS M teatr M dwor. 12 SECOND FUNCTION OF FSTN –RECOGNITION (Findingoutparticularfinitetransition) Question: Is it possible to find out sequence of transition :14,15,10 ?-NOT RECOGNIZED D,14,6 ?-RECOGNIZED

  6. FSTN - RECOGNIZING \ GENERATING y 2 3 b e ! 1 4 5 l 2 3 e i RECOGNIZING GENERATING From 1 to 2 by b From 1 to 2 by l From 2 to 3 by y From 2 to 3 by i From 3 to 4 by e From 4 to 5 by ! B,y,e –From 1 to 2 by b From 2 to 3 by y From 3 to 4 by e B,e,y – Not recognized

  7. A net with at least one state from which more than one arc with the same label traverses. NON-DETERMINISTIC FSTN # y e ! b 1 2 3 4 5 y Non-deterministic state 2 has two choices : Return to state 1 (in attempt to find the following ‘b’ Move to state 3 FINITESTATENETWORKWITH „JUMP” ARC A net which has unlabelled jump arc, which means that when the machine is generating or recognizing, it can traverse such an arc and jump without consuming any symbols from the input string.

  8. SAMPA SAMPA (Speech Assessment Methods Phonetic Alphabet) is a machine-readable phonetic alphabet. In the present study IPA phonetic transcription was not used for encoding phonemes because some of its symbols are inconvenient for computer processing, e.g. QNZD f.e POLISH ENGLISH SAMPA SAMPA X hymn xImn V cut kVt Ts cyrk tsIk D this DIs o~ wąs vo~sQ pot pQt

  9. ABBREVIATIONS A From 1 to 2 by A A abbreviates: a,b,c 1 2 a From 1 to 2 by a From 1 to 2 by b From 1 to 2 by c b 1 2 c

  10. APPLICATION OF FSTNs Used in: linguistic analyses (esp. in phonology, morphology and syntax) almost all branches of industry (most machines are FSA’s) telecommunication (e.g. storage of telephone numbers) etc.

  11. SUMMARY 1) Finite-State Transitional Network- an case of a finite state automation. 2) Diagram of FSTN-has initial and final state. 3) Function of FSTN: a) to generate - creating all strings that agree with the ‘knowledge’ of FSTN b) to recognize - finding out strings that agree with the ‘knowledge’ of FSTN 4) Non-deterministic FSTN - A net with at least one state from which more than one arc marked by the same label.traverses 5) FSTN with a ‘jump’ - A net with unlabelled jump arc. 6) SAMPA-Symbols for phonetic representations.

  12. THE END OF FINITE-STATE TRANSITION NETWORKS

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