1. Towards Contextual and Structural Relevance Feedback in XML Retrieval Lobna Hlaoua IRIT (Institut de Recherche en Informatique de Toulouse) Equipe SIG-RI (Systèmes d’Informations Généralisées) 118, route de Narbonne - 31062 Toulouse cedex 04

2. Outline Context Relevance Feedback in XML Retrieval Contextual Relevance Feedback Structural Relevance Feedback Conclusion & prospects

3. Context: XML Retrieval -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ -- --- ------ ----- ------ Traditional IR - Document is atomic unit - user can be submerged by noisy subjects

4. Context: XML Retrieval Ontologies J.Dupond history of ontology Introduction...ontology should be seen only as an interdiscipline... What is Ontology...An ontology is an explicit specification of a conceptualization... In the philosophical sense, we may refer to an ontology as a particular system of categories accounting for a certain vision of the world….. …. XML Retrieval - different granularities

5. Context: XML Retrieval Ontologies J.Dupond history of ontology Introduction...ontology should be seen only as an interdiscipline... What is Ontology...An ontology is an explicit specification of a conceptualization... In the philosophical sense, we may refer to an ontology as a particular system of categories accounting for a certain vision of the world….. …. « ontologies case study » - CAS (Content And Structure) Ex: - CO (Content Only) Ex : « //article[about(.,ontologies)] //sec[about(., ontologies case study)] » «//article[about(.,ontologies)]» «//article[about(.,ontologies)] //para[about(., ontologies case study)] » In the philosophical sense, we may refer to an ontology as a particular system of categories accounting for a certain vision of the world….. What is Ontology...An ontology is an explicit specification of a conceptualization... In the philosophical sense, we may refer to an ontology as a particular system of categories accounting for a certain vision of the world….. Ontologies J.Dupond history of ontology Introduction...ontology should be seen only as an interdiscipline... What is Ontology...An ontology is an explicit specification of a conceptualization... In the philosophical sense, we may refer to an ontology as a particular system of categories accounting for a certain vision of the world….. ….

6. Relevance Feedback (RF) RF in traditional IR consists in enriching the initial query using terms extracted from relevant documents. How RF can be used in XML retrieval ?

7. Relevance Feedback (RF) in XML Retrieval Problems –How extracting terms from retrieved elements having different semantic element could (title, section, paragraph, etc.) … whereas in IR only document units are considered –How structural constraints can be extracted from relevant elements –How enriching XML queries : adding structural constraints And/OR keywords in both CO and CAS queries?

8. Our approach Contextual RF –expand the query with expressive words according to the context of the judged component from different granularities. Structural RF –select the more appropriate generative structure from judged components and adding to CO query.

9. Process of RF in XML Retrieval Relevant components Extraction of expressive terms Extraction of relevant structure Initial query Relevance Feedback Reformulated query Results RC+ NRC

10. Objective: select the more expressive words Let’s consider E r ={e r 1, e r 2,..., e r k,... e r m }, e r k ={l 1,..., l j,.l n } –assign a score to terms (t i) occurring in each leaf node (l j ) of the relevant elements. –Compute the score of terms of in each element (e r k ). –Select the best terms according to number of occurrence in relevant elements. Contextual Relevance Feedback

11. Structural Relevance Feedback Objective is to select the more appropriate generative structure –retrieve the smallest common ancestor –attribute scores for each structure Si is the structure of relevant element having a joint base with the candidate structure n is a number of the relevant elements d is the distance which separates nodes  is a constant vaying in [0,1]

12. Example of RF in CO query Initial query Q: “ information retrieval ” Structural RF – we suppose that relevant structures have the following scores: /book/chapter/section/subsection (0.4) /book/chapter/section/subsection/para (0.4) /book/chapter/section/title (0.2) Q2: “ article//sec[about(., information retrieval)] ”

13. Conclusion & prospects Outlined the problem of Relevance Feedback in XML Retrieval. New challenge in IR : up until now only very few related works Our investigations can be considered as a first step of a long hard work. The main idea behind theses investigations: –how keywords and structural constraints can be selected and added to CO queries. Experiments will be carried out “soon” in INEX framework

14. THANK YOU

15. Contextual Relevance Feedback book num=1 Introduction Internet knowledge …. Search engine chapter Yahoo... Google….. autho r J. Dupont title section titlepar a section titlepar a chapter title Web access Leaf node Node Search engine title num=2 date-publi=2000

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18. Structural Relevance Feedback book chapter author title section title para section title para chapter title... anc[9] des[4] sca[11,13] 1 11 10 7 8 4 6 32 9 5 1413 12