This thesis deals with an implementation of algorithm for computation of generator of almost split sequences ending at an indecomposable nonprojective module of path algebra over finite quiver. Algorithm is implemented in algebra system GAP (Groups, Algorithms, Programming) with additional package QPA (Quivers and Path Algebras). Powered by TCPDF (www.tcpdf.org)

The purpose of this study is to examine the difference between three query strategies with respect to retrieval effectiveness. The thesis aims at examining how two types of noun phrases containing a modifier to the head word, which is a noun affect the retrieval performance with regard to recall and precision. The noun phrases in the thesis are of two types: 1) noun phrases containing a modifier to the head word (which is a noun) and which are not dictionary phrases (NF) and 2) dictionary phrases. Both types of noun phrases in this thesis contain at least two words. The queries were executed in Query Performance Analyser, QPA, containing the InQuery system and a sub collection of TREC-Uta documents with its topics. The measures used were R@200 and precision at 13 document cut-off values. In total, 20 topics were examined. All the documents and the queries were in English. The result of this study indicates that NFs have a negative effect on the retrieval performance and that dictionary phrases have a rather neutral effect on the retrieval performance. / Uppsatsnivå: D

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