Abstract. In this paper we report on the application of two contrasting types of relevance feedback for web retrieval. We compare two systems; one using explicit relevance feedback (where searchers explicitly have to mark documents relevant) and one using implicit relevance feedback (where the system endeavours to estimate relevance by mining the searcher's interaction). The feedback is used to update the display according to the user’s interaction. Our research focuses on the degree to which implicit evidence of document relevance can be substituted for explicit evidence. We examine the two variations in terms of both user opinion and search effectiveness. 1

A new laboratory-based method for the evaluation of Boolean queries in free-text searching of full-text databases is proposed. The method is based on a controlled formulation of inclusive query plans, on an automatic conversion of query plans into a set of elementary queries, and on composing optimal queries at varying operational levels by combining appropriate sub-sets of elementary queries. The method is based on the idea of reverse engineering, and exploits full relevance data of documents to find the query performing optimally within given operational constraints. The proposed

Web searchers typically fail to view search results beyond the first page nor fully examine those results presented to them. In this article we describe an approach that encourages a deeper examination of the contents of the document set retrieved in response to a searcher’s query. The approach shifts the focus of perusal and interaction away from potentially uninformative document surrogates (such as titles, sentence fragments, and URLs) to actual document content, and uses this content to drive the information seeking process. Current search interfaces assume searchers examine results document-by-document. In contrast our approach extracts, ranks, and presents the contents of the top-ranked document set. We use query-relevant topranking sentences extracted from the top documents at retrieval time as fine-grained representations of topranked document content and, when combined in a ranked list, an overview of these documents. The interaction of the searcher provides implicit evidence that is used to reorder the sentences where appropriate. We evaluate our approach in three separate user studies, each applying these sentences in a different way. The findings of these studies show that top-ranking sentences can facilitate effective information access.

As Chinese is not alphabetic and the input of Chinese characters into computer is still a difficult and unsolved problem, voice retrieval of information becomes apparently an important application area of mobile information retrieval (IR). It is intuitive to think that users would speak more words and require less time when issuing queries vocally to an IR system than forming queries in writing. This paper presents some new findings derived from an experimental study on Mandarin Chinese to test this hypothesis and assesses the feasibility of spoken queries for search purposes. 1

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Due to both the size and growth of the internet, new tools are needed to assist with the finding and extraction of very specific resources relevant to a user's task. Previously, the definition of relevance has been related to the matching between documents and query terms but recently the emphasis is shifting towards a more personalised model based on the relevance of a particular resource for one specific user. In this paper, we introduce our system, Fetch, which adopts this concept within an informationseeking environment specifically designed to provide users with means to describe a long-term multifaceted information need. By taking advantage of the way in which users bundle together groups of documents representing a particular topic, query languages as we know them can be taken to a higher and more useful level of abstraction. The agent personalises the search experience by using this information to formulate queries with the aim of returning documents relevant to the user's information need. In this paper we report on both qualitative and quantitative aspects of system use based on information collected in the pilot evaluation.