1. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab1 LG617 A brief introduction to XLE Kakia Chatsiou achats@essex.ac.uk Dept of Language and Linguistics University of Essex

2. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab2 Outline About XLE Where is XLE used? –ParGram Project Project Objectives Participating Members –Powerset –XLE Web interface A closer look at XLE –Grammar architecture –Inspecting a basic grammar.lfg file –XLE interface –XLE vs LFG notations Hands-on Session

3. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab3 About XLE XLE stands for Xerox Linguistics Environment Under current development at PARC (Palo Alto Research Center, USA) A computational environment developed to facilitate the writing and debugging of Lexical Functional Grammars C-structure, f-structure, s-structure, and further projections can be defined Implemented in C; works in Unix, Linux, MacOS. Integrates a morphological analyser employing Finite State Technology Can be used for both parsing and generation Includes tools for various grammar development activities (such as analysing performance, test-suites)

4. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab4 Where is XLE used? ParGram Project PowersetThe core technology used in the consumer search engine based on natural language processing which is currently under development by Powerset

5. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab5 Where is XLE used? :: ParGram Project :: Project Objectives Broad coverage grammars –Inclusion of important and frequently occurring constructions –Linguistically motivated analyses Parallel and crosslinguistic development of grammars between the participating members –All grammars are guided by a common set of linguistic principles and a commonly agreed upon set of grammatical analyses and features –Identical treatment of core crosslinguistic phenomena Methods in grammar engineering –Common test methods and evaluation strategies –Balance between efficiency, performance, reliability and maintainability across grammars

6. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab6 Participating Members PARC, CA Chinese, English, French Essex Greek, Welsh Manchester Arabic Oxford Malagasy DCU, Ireland Chinese, English, French, German, Japanese, Spanish Fuji XEROX Japanese Bergen, Norway Georgian, Norwegian, Tigrinya Ho Chi Minch Vietnamese Debrecen Hungarian IMS, Stuttgart German Konstanz Urdu Sabanci, Istanbul Turkish Where is XLE used? :: ParGram Project ::

7. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab7 search enginea Silicon Valley Company, currently building a transformative consumer search engine based on natural language processing: –It is based on technologies that take advantage of the structure and nuances of natural language –It offers an innovative approach to searching: It breaks the confines of keyword search  queries using both keywords, short phrases and natural language Makes search more natural and intuitive Aims at fundamentally changing how we search the web and at the same time delivering higher quality results currently searching Wikipedia with the help of FreeBase as the semantic knowledge database (source: http://www.powerset.com )http://www.powerset.com Where is XLE used? :: Powerset Search Engine ::

8. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab8 Where is XLE used? :: Powerset Search Engine ::

9. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab9 Example queries Who is Indiana Jones? Which are the films that Spielberg directed? I am looking for Van Gogh’s paintings Paintings by Van Gogh Albums by westlife Books by Charles Dickens Where is XLE used? :: Powerset Search Engine ::

10. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab10 a web-based tool for parsing LFG grammars using the XLE tool outputs c-structures, f-structures and mrs-structures. allows the user to choose a grammar and type in a sentence to be analyzed. The sentence is then processed by the XLE parser, and the resulting structures are displayed. has a facility for uploading (small) user grammars, mainly for teaching purposes. Where is XLE used? :: The XLE Web Interface ::

11. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab11 A closer look at XLE Grammar architecture? Inspecting a basic grammar.lfg file –Inspecting the config file? –Inspecting a rule –Inspecting a lexical entry XLE interface XLE vs LFG notations

12. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab12 Other Finite State Tools Other Finite State Tools Tokenizer Morpholo- gical Analyser FST Morpholo- gical Analyser FST Lexicon(s) (Hand-written Or Automatically Extracted) Lexicon(s) (Hand-written Or Automatically Extracted) LFG Grammar (rules, templates) LFG Grammar (rules, templates) Grammar Resources (parsing and generating) Grammar Resources (parsing and generating) A closer look at XLE :: Basic Grammar Architecture ::

13. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab13 A closer look at XLE :: Inspecting a grammar file ::

14. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab14 A closer look at XLE :: XLE interface :: C- structure f- structure Packed representa- tion of f- structures Representa- tion logical choices (in cases of ambiguity) % parse {Mary saw the boys with the telescope} parsing {Mary saw the boys with the telescope} 2 solutions, 0.01 CPU seconds, 23 subtrees unified

15. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab15 LFG notationXLE-equivalentDescription ↑ ^f-structure metavariable ↓ !f-structure metavariable ==defining equality ≡ =meta-category definition =c=c or =Cconstraining equality ∈ $set membership ¬~negation (complementation) ddexistential constraint (standard notation) ∃ ddexistential constraint (Sadler) ← <-off-path constraint → ->off-path constraint ⊑ <<subsumption (subsumes) ⊒ >>subsumption (is subsumed by) { a | b | c |... | z }{ a | b | c |... | z }disjunction ( a ){ a }optional f-structure constraint A closer look at XLE :: XLE vs LFG Notations ::

16. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab16 Hands-on Session

17. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab17 References / Sources ParGram http://www2.parc.com/isl/groups/nltt/pargram/ XLE Web Interface Documentation: http://maximos.aksis.uib.no/Aksis-wiki/XLE-Web http://maximos.aksis.uib.no/Aksis-wiki/XLE-Web XLE Documentation http://www2.parc.com/isl/groups/nltt/xle/doc/xle_toc.html Powerset http://www.powerset.com/

18. Kakia Chatsiou A brief introduction to XLE 26.02.2009LG617 - XLE Lab18 Thank you! For more information and updates on the progress of the project visit http://privatewww.essex.ac.uk/~achats/projects/greekgram/index.html