research side of prototypical search methods, [28] [7 E Ario,K P. Saatsi, J. Kekalainen, S. Suomela applies fuzzy qualifiers to complex constraint queries, ased query interface for text retrieval In pre WIth artificial Intelligence Conf, 200 while in [29], the idea is presented that user profiling [8]J.Heflin, J,Hend Searching the web with SHOE, In could be used as a basis for weighting the relevance of an ontological relation to be used in the search [9]A. Maedche, S. Staab, N. Stojanovic, R. Studer, Y. Sure, In Proc. 18th British National Conf. on DB, Pp. I VI. DISCUSSION AND CONCLUSION lO E. Makela, E. Hyvonen, T. Sidoroff,"View-based user interfaces for information retrieval on the semantic web. In A number of common patterns can be detected in Workshop End User Interaction, 200s emantic web,"In the approaches described in this paper. On the [11] E Makela,EHyvonen, S Saarela, K. Viljanen,"OntoViews a tool for creating semantic web portals, In Proc. 3rd Int technical level. it can be concluded that in the Conf Semantic Web, Springer Verlag, 2004 orking context of an RDF model, quite many of the [12] E Hyvonen, S Saarela, KViljanen, "Ontogator: Combining used common methodologies are of general nature view- and ontology-based search with semantic browsing, "In roc. XMLFinland 03 oct 200 Usually complex constraint queries are focused on [13] D. Reynolds, P. Shabajee, S Cayzer, "Semantic information models where individuals and classes are the portals,In Proc. 13th Int World wide Web Conf, 2004 interesting information items: we can observe [14] N. Stojanovic, J. Gonzalez, L. Stojanovic, "Ontologer -A system for usage-driven management of ontology-based relations which are present as equal partners in all the information portals, "In Proc. L-CAP 03 Conf, 2003 graph pattern, path and logic formalisms. After the [15] N Stojanovic, "On the role of a Librarian Agent in onto deduction of a result set by using complex constraints, nanagement systems, J. there are strong tendencies to use graph traversal [16]N. Stojanovic, "Information-need driven query refinement," algorithms to locate additional result items. while In Proc. IEEE/IC Int Conf Web Intelligence, 2003 zzy logic formalisms and fuzzy concepts allow us to [7 N. Sto ic,R. Studer, L Stojanovic, "An Approach fc Step-By-Step Query Refinement in the Ontology-Based combine keyword search results as equal part Information Retrieval, In Proc. Int. Conf. on Web mplex constraint querying. intelligence, 2004 Besides, the ontology-based query refinement, [18 Dy, R, Karger, K. Bakshi, D D. Quan, V. Sinha, which includes ranking issue and user-interaction, can for end users based on semistructured data. In Proc. CIDR be recognized as innovative approach for improvement of query precision and helping users [19] D Quan, D Huynh, D R Karger, " Haystack: A platform for authoring end user semantic web clarify their queries from ambiguous initial ones. The Int. Semantic Web Conf, pp. 738-753, 2003 query refinement has been started very early along [20]L. Kerschberg, M. Chowdhury, A. Damiano, et al, with the query process in semantic web application Knowledge Sifter: Ontology-Driven Searchover which uses simple expansion algorithms. The current geneous Databases, In Proc. 16th Int. Conf. Scientific and Statistical DB Management, 2004 approaches have proved their power with effective [21]S Decker, M. Erdmann, D Fensel, R. Studer, "Ontobroker refinement strategies based on ontologies. The only Ontology-based Access to Distributed and Semi-Structured approach which does not neatly wrap into the others is Multimedia Systems, pp 351-369, Kluwer Publishers, 1999 inference-based problem solving. Inference in general [22]S. Hubner, R. Spittel, U. Visser, T.J. Vogele,"Ontole builds a much greater challenge for the most usual ased Search Interactive D cases of ontology-based query systems Intelligent Systems, Vol. 19(3), pp 80-86, May-Jun 2004 A summary of the discussed ontology-based query [23] N.Athanasis,V Christophides, D. Kotzinos, "Generating on the fly queries for the semantic web: The ICS-Forth Graphical systems according the common criteria is presented in RQL Interface (GRQL), In Proc. 3rd Int. Semantic Web the Table i on,pp.486-501,2004 224 T. Catarci, P. Dongilli, T. D. M E. Franconi, G Santucci, S. Tessaris tology based visual tool for REFERENCES query formulation support, In Proc. 16th Euro. Conf. on 4 pp.308-312,2004. [] M. Rila. "The Use of WordNet in information retrieval, "ACL [25] L. Zhang, Y. Yu, J. Zhou, C. Lin, Y. Yang, An enhanced Workshop on the Usage of WordNet In Natural Language model for searching in semantic portals, "In Proc. 14th Int. 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