The aim with this thesis came out of a strong interest for Passage retrieval. Our intention has not been to evaluate an IR-system. Instead our goal has been to analyze the result of indexing documents and their passages. We have been studying the weights of the different terms in the different indices, in comparison with other parameters like frequency, normalized frequency and the inversed document frequency. Further more we have been looking at how the weights are spread using for instance the standard deviation.

The aim of this thesis is to describe Passage retrieval (PR), with basis in results from various empirical experiments, and to critically investigate different approaches in PR. The main questions to be answered in the thesis are: (1) What characterizes PR? (2) What approaches have been proposed? (3) How well do the approaches work in experimental information retrieval (IR)? PR is a research topic in information retrieval, which instead of retrieving the fulltext of documents, that can lead to information overload for the user, tries to retrieve the most relevant passages in the documents. This technique was investigated studying a number of central articles in the research field. PR can be divided into three different types of approaches based on the segmentation of the documents.

This thesis deals with one of the main questions within information science: The question about controlled and uncontrolled vocabulary and which of the two that are most effective when it comes to retrieve relevant information from electronic databases. The method used here is literature studies. I have described and examined five empirical studies which has been done in purpose to compare the effectiveness in retrieval with controlled and uncontrolled vocabulary, in the way they are used in retrieval of information in databases. The studies I have examined have also used recall and precision as a value to measure the effectiveness of retrieval. The studies which I have chosen is also limited to deal only with studies that have been done in bibliographic databases.

This Master?s thesis examines different retrieval strategies used in cross-language information retrieval (CLIR). The aim was to investigate if there were any differences between baseline queries and translated queries in retrieval effectiveness; how the retrieval effectiveness was affected by query structuring and if the results differed between different languages. The languages used in this study were Swedish, English and Finnish. 30 topics from the TrecUta collection were translated into Swedish and Finnish.

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.

Scintigraphic examination of the esophagus has for some time been the method of choice for the study of motility dysfunction in humans. The method has not yet been described for horses hence the lack of reference values for passage time for a bolus through the esophagus in healthy subjects. The purposes of this study were to measure passage velocity and time for a bolus to pass through the esophagus in healthy subjects, as well as to evaluate the reproducibility of the method. Eight warm-blooded trotters were used in the study. The horses were sedated with a low dose of Acepromazine prior to onset of the study.

The purpose of this essay is to examine how high school students (age 13 to 19) search for information on the web and in databases. Furthermore, it aims to look into how critical of sources they are. The questions asked was: how the students search for information in digital media? Which kind of sources do the students use? How they evaluate the information they find? Do they get any education in information retrieval and source evaluation? To answer these questions students were interviewed in groups about their information retrieval behavior. Furthermore two school librarians were interviewed about their experience of the students? information retrieval.During the interviews it was clear that the students had received quite sparse instructions on the subjects of information retrieval and criticism of the sources.

The aim of this master thesis is to evaluate the performance of the content-based image retrieval system ImBrowse from a semantic point of view. Evaluation of retrieval performance is a problem in content-based image retrieval (CBIR). There are many different methods for measuring the performance of content-based image retrieval systems, but no common way for performing the evaluation. The main focus is on image retrieval regarding the extraction of the visual features in the image, from three semantic levels. The thesis tries to elucidate the semantic gap, which is the problem when the systems extraction of the visual features from the image and the user?s interpretation of that same information do not correspond.

This essay is focused on the re-use during the Bronze Age of the Stone Age passage grave RAÄ 85 in Mysinge, Öland. To increase the knowledge of the phenomena of re-use in general and that which occurred in Mysinge passage grave in particular I?ve looked at other forms of re-use on Öland and the re-use of passage graves in Falbygden. The research has been limited to the Bronze Age. My goal has been to see what this might tell us about the relationship people during the Bronze Age had towards the abstract subject of ?non-existence?, in other words death.

This master thesis deals with events, dynamics and problems of mediated information seeking within the context of a new information service called "Book a librarian". The study, based on a survey and interviews both in academic and public libraries and participant observations in academic libraries, has its theoretical base in the cognitive theory of information retrieval interaction. The cognitive view is used to throw light upon the need of an ongoing dialogue during the session in order to detect the information needs of the user and to conduct a successful retrieval of information. The communicative interaction is seen as threepart interaction between the intermediary, the user and the information system, where the current cognitive states of all three participants are involved. The study shows that the cognitive obstacles for a successful mediation and information retrieval are mostly connected to participants current knowledge of the subject and of the retrieval techniques.

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.

This essay is focused on the re-use during the Bronze Age of the Stone Age passage grave RAÄ 85 in Mysinge, Öland. To increase the knowledge of the phenomena of re-use in general and that which occurred in Mysinge passage grave in particular I?ve looked at other forms of re-use on Öland and the re-use of passage graves in Falbygden. The research has been limited to the Bronze Age. My goal has been to see what this might tell us about the relationship people during the Bronze Age had towards the abstract subject of ?non-existence?, in other words death.

As the information society becomes increasingly flooded with digital images, the need for efficient image retrieval systems increases as well. To handle the vast amounts of data involved, the indexing process needs to be run automatically, using content-based descriptors extracted directly from the digital image, such as colour composition, shape and texture features. These content-based image retrieval systems are often slow and cumbersome, and can appear confusing to an ordinary user who does not understand the underlying mechanisms. One step towards more efficient and user-friendly retrieval systems might be to adjust the weight placed on various descriptors depending on which image category is being searched for. The results of this thesis show that certain categories of digital images would benefit from having extra weight assigned to colour, texture or shape features when searching for images of that category..

The purpose of this paper is to examine the three main translation methods used in experimental Cross-language Information Retrieval CLIR research today, namely translation using either machine-readable dictionaries, machine translation systems or corpus-based methods. Working notes from research groups participating in the Text Retrieval Conference TREC and the Cross-Language Evaluation Forum CLEF between 1997 and 2000 have provided the main source material used to discuss the possible advantages and drawbacks that each method presents. It appears that all three approaches have their pros and cons, and because the different researchers tend to favour their own chosen method, it is not possible to establish a "winner approach" to CLIR translation by studying the working notes alone. One should remember however that the present interest in cross-language-applications of information retrieval has arisen as late as in the 1990s, and thus the research is yet in its early stages. The methods discussed in this paper may well be improved, or perhaps replaced by others in the future..

Due to exploitation of the world?s rivers, the upstream migration of anadromous species is frequently delayed or even prevented. To mitigate these problems and allow fish to migrate past obstacles, structures such as fish ladders have been developed. However, recent studies show that many of the present fish passage facilities are deficient. Monitoring and evaluation of passage facilities is therefore crucial to enable necessary adjustments.