The aim of this thesis was to evaluate the music downloading service Musikwebb regarding its indexing and retrieval effectiveness. This was done by performing various kinds of search in the system. The outcome of these searches were then analysed according to the criteria specificity, precision, recall, exclusivity and authority control. The study showed that Musikwebb had several flaws regarding its retrieval effectiveness. The most prominent cases were the criteria exclusivity and specificity.

The wide spread of the Internet and new information technologies in recent years has come to effect how libraries manage and disseminate information. Search engines like Google are widely used by people who often find the Information retrieval systems of libraries to be too complicated. In 2004 Google announced plans to digitise five major library collections. Organisations representing the publishing industry and authors have since then filed lawsuits against Google claiming that Googles scanning of library books infringe the rights holders copyright. Due to Googles potential impact on libraries this thesis aims to examine how Googles digitisation project, Google Book Search, has been received in the library community.

The purpose with this study is to map the research front and the research base in information science, by using the bibliometric methods bibliographic coupling and author-co citation analysis. The research questions are: 1. What is the nature of the research front in information science, regarding which areas that are being studied? 2. What is the nature of the research base in information science, regarding which authors who are most cited, and how they can be grouped? The data used in the study were gathered from articles published in the journal Journal of the American society for information science and technology, published between 2004-2006, respectively 1986-2006.

The aim of this study was to compare the Query-by-Humming systems Midomi, Musicline and Tunebot regarding their retrieval effectiveness. The aim was to see if there were differences between the systems but also between the user groups common users, musicians and singers. Query-by-Humming system means that the user sings a tune that the system then use to find the right melody.To compare the systems and their users, queries where collected from the different user groups and replayed for the systems. Mean Reciprocal Rank and Friedman test was used to do the comparison.The results showed that the system did not achieve equivalent and that there were no difference between the user groups. The Mean Reciprocal Rank showed that the systems had very different retrieval effectiveness, where Midomi was the system with best result and Musicline with the lowest result..

This thesis compares four relevance feedback methods. The Rocchio and Ide dec-hi algorithms for the vector space model and the binary independence model and Okapi BM25 within the probabilistic framework. This is done in a custom-made Information retrieval system utilizing a collection containing 131 896 LA-Times articles which is part of the TREC ad-hoc collection. The methods are compared on two grounds, using only the relevance information from the 20 highest ranked documents from an initial search and also by using all available relevance information. Although a significant effect of choice of method could be found on the first ground, post-hoc analysis could not determine any statistically significant differences between the methods where Rocchio, Ide dec-hi and Okapi BM25 performed equivalent.

In information retrieval there is a problem with ambiguous words. To solve this problem word sense disambiguation WSD is used. Few studies combining Information retrieval and word sense disambiguation have been conducted with Swedish words. The purpose of this thesis has been divided in two. The first purpose was to examine Swedish Information retrieval and disambiguation in the query phase.

The aim of this study is to analyze and describe the research front within information science. To reach this purpose we ask the following research question: Which research themes can be identified within the subject field of information science by using bibliographic coupling in combination with cluster analysis.The data for our study consists of articles from the journals Journal of the American Society for Information Science and Technology and Journal of Documentation throughout the years 2004-2006. The bibliographic information from the articles was analyzed with the combined methods of bibliographic coupling and cluster analysis. This gave fifteen clusters within which we identified research themes. When analyzing these results we found four main fields of research within the research front of information science: Information retrieval, bibliometrics, knowledge organization and information science as research discipline.

The thesis deals with three document retrieval models based on logic: the Boolean model,the fuzzy model and the Van Rijsbergen model.In Chapter 1, the author presents the purpose of the thesis. This is to give the logical foundationof the models, to describe them and to examine them critically. In Chapter 2, some importantnotions in document retrieval are presented. Chapter 3 is devoted to the Boolean model, Chapter4 to the fuzzy model and Chapter 5 to the Van Rijsbergen model.These three chapters are organized in the same way. First, the logical foundation of the modelis given.

The thesis aims at, from a user perspective, examining how a group of industrial researchers understand the information seeking in their every day work. A qualitative method is employed. The empirical material consists of open-ended interviews with in all ten researchers. All of them work at the Swiss-Swedish Technology Company ABB's research laboratory in Västerås. The thesis is based on the opinion that the scientific knowledge production has become commercialised and that the scientific communication is going through certain changes.

Na?r en student idag utbildar sig vid ett svenskt la?rosa?te beho?ver denne info?rskaffa sig kurslitteratur som ett komplement till undervisningen. Det finns inget sja?lvklart tillva?gaga?ngssa?tt fo?r hur studenten info?rskaffar sig sin kurslitteratur och information om litteraturen presenteras inkonsekvent o?ver olika ka?llor . Vi utvecklar da?rfo?r ett sto?dsystem fo?r so?kning av kurslitteratur, med syfte att effektivisera so?kprocessen samt att exponera studenten fo?r eventuellt tidigare fo?rbisedda ka?llor till kurslitteratur. Systemet utva?rderas i fo?rha?llande etablerade so?kstrategier hos 22 studenter. Resultaten visar att anva?ndandet av detta sto?dsystem inte bara minskar antalet steg markant utan a?ven minskar antalet tja?nster studenten anva?nder fo?r att info?rskaffa sin kurslitteratur ja?mfo?rt med studenters egna so?kstrategi idag..

The aim of this thesis is to investigate librarians? experiences and opinions about a system for fiction retrieval based on the subject headings list Att indexera skönlitteratur. I want to know if librarians experience that subject headings searches for fiction literature are a good working tool, if there according to librarians are other resources and means that makes fiction available and searchable, and how they estimate the possibility of non-professionals to use subject headings for fiction retrieval. Six librarians at public libraries in Göteborg where interviewed. The interviews dealt with their work with fiction literature, their experiences of subject headings as a fiction retrieval tool, and with their contacts with patrons.

In query expansion (QE) terms are added to an initial query in order to improve retrieval effectiveness. In this thesis we use QE in the sense that a reformulation of the query is done by deleting the terms in the initial query and instead replacing them with terms from the documents retrieved in the initial run. The aim of this thesis is to, in a experimental full text invironment, study and compare the retrieval result of two different query expansion strategies in relation to each other. The following questions are addressed by the study: How do the two strategies perform in relation to each other regarding recall? What may be causing the result? Are the two strategies retrieving the same relevant documents? Two strategies are designed to simulate a searcher using automatic query expansion (AQE) either with or without relevance feedback.

The purpose of this essay was first and foremost to find out the problems that exist around user education in a university library and the opportunities that exist for university librarians to improve their work with students. My method of use was qualitative and more precise qualitative interviews. By interviewing five teaching librarians with five different subject specializations, I wanted to get an an-swer to what they teach when they meet the students and how they view their teaching. Responses resulted then in an analysis using Christine Bruce's theory of information literacy and Carol C. Kuhlthaus theory of librarian roles and her theory of Information retrieval process.

The aim of this thesis is to examine how thesauri constructed with latent semantic indexing LSI are performing when used for query expansion. There is a well-known problem with synonymy in Information retrieval and one solution to this problem is to use a thesaurus. In this thesis thesauri are created automatically to find statistically related words and not only synonyms. LSI is a method that uses singular value decomposition SVD to reduce dimensions in a matrix and find latent relationships between words. We constructed nine thesauri and used them for query expansion in a Swedish database, GP_HDINF.

This thesis deals with query formulation in full text retrieval. The variables studied were query expansion and query structur[INS: e :INS , and the aim of the thesis is to study their co-effects on retrieval performance in a probabilistic system. The expansion was made with synonyms, and the structure by expressing facets and phrases. The study was performed using QPA, Query Performance Analyzer, which includes InQuery retrieval system and a sub-collection of TREC documents with its topics. The measurement used was precision at 11 DCV points.