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Одна из основных задач информационного поиска—извлечение документов, релевантных информационной потребности пользователя, выраженной запросом. Зачастую пользовательские запросы не превосходят 3 слов, что усложняет задачу. Многочисленные исследования показали, что автоматическое расширение запроса в среднем повышает точность, несмотря на то, что для некоторых запросов результаты ухудшаются. В ст...

The problem to decide whether a given multivariate (quasi-)rational function has only positive coefficients in its power series expansion has a long history. It dates back to Szegö [10], who showed that ((1−Z1)(1−Z2) + (1−Z1)(1−Z3) + (1−Z2)(1−Z3)) for β ≥ 1/2 is positive, in the sense that all its series coefficients are positive, using an involved theory of special functions. In contrast to th...

Document type: Journal: Volume: Number: Pages: Additional material: Language: 2 documents’ titles. This is illustrated by the excerpt from a result list which is presented in Figure 41. Figure 41: Excerpt from a result list In the result list, the document titles were interlinked with the respective metadata pages of the documents. Amongst others, these pages presented the following information...

In this paper, we describe the search system, developed at Ghent University for the TREC 2012 Microblog Track in order to rank Twitter messages or ‘tweets’ from a fixed corpus in response to a number of search requests. Our system ranks the tweets based on a Logistic Regression classifier trained with data from the Microblog Track 2011. The features used for training the classifier include loca...

The 2016 CLEF eHealth Task 3 aims to evaluation the effectiveness of information retrieval systems when searching for health content on the web. The ClueWeb12 B13 data set is utilized in this task. This paper presents our work on the 2016 CLEF eHealth Task 3. We propose a Web-based query expansion method and a combination method to better understand and satisfy the task. In particular, we test ...

For this first participation to the CHiC Lab, we focused on understanding the challenges of working with a collection of cultural heritage objects with short textual descriptions and on how to fine-tune a set of weighting models from the probability models based on Divergence From Randomness to perform uniformly in monolingual and multilingual scenarios. The official runs submitted used PL2 as ...

This paper describes our participation in the CLEF 2004 French monolingual task. We used our Terrier Information Retrieval platform and experimented with query expansion and query length normalisation.

This paper reports on a study to explore how semantic relations can be used to expand a query for objects in an image. The study is part of a project ith the overall objective to provide semantic annotation and search facilities for a virtual collection of art resources. In this study we used semantic elations from WordNet for 15 image content queries. The results show that, next to the hyponym...