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dc.contributor.advisorOlstad, Bjørnnb_NO
dc.contributor.advisorTorbjørnsen, Øysteinnb_NO
dc.contributor.authorBjørklund, Truls Amundsennb_NO
dc.date.accessioned2014-12-19T13:33:42Z
dc.date.available2014-12-19T13:33:42Z
dc.date.created2010-09-04nb_NO
dc.date.issued2007nb_NO
dc.identifier348566nb_NO
dc.identifierntnudaim:3280nb_NO
dc.identifier.urihttp://hdl.handle.net/11250/251238
dc.description.abstractThis report aims to asses the efficiency of various inverted indexes when the indexed document collection is dynamic. To achieve this goal, we experiment with three different overall structures: Remerge, hierarchical indexes and a naive B-tree index. An efficiency model is also developed. The resulting estimates for each structure from the efficiency model are compared to the actual results. We introduce two modifications to existing methods. The first is a new scheme for accumulating an index in memory during sort-based inversion. Even though the memory characteristics of this modified scheme are attractive, our experiments suggest that other proposed methods are more efficient. We also introduce a modification to the hierarchical indexes, which makes them more flexible. Tf-idf is used as the ranking scheme in all tested methods. Approximations to this scheme are suggested to make it more efficient in an updatable index. We conclude that in our implementation, the hierarchical index with the modification we have suggested performs best overall. We also conclude that the tf-idf ranking scheme is not fit for updatable indexes. The major problem with using the scheme is that it becomes difficult to make documents searchable immediately without sacrificing update speed.nb_NO
dc.languageengnb_NO
dc.publisherInstitutt for datateknikk og informasjonsvitenskapnb_NO
dc.subjectntnudaimno_NO
dc.subjectSIF2 datateknikkno_NO
dc.subjectKomplekse datasystemerno_NO
dc.titleExperimentation with inverted indexes for dynamic document collectionsnb_NO
dc.typeMaster thesisnb_NO
dc.source.pagenumber552nb_NO
dc.contributor.departmentNorges teknisk-naturvitenskapelige universitet, Fakultet for informasjonsteknologi, matematikk og elektroteknikk, Institutt for datateknikk og informasjonsvitenskapnb_NO


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