Maximal termsets as a query structuring mechanism

Abstract

Search engines process queries conjunctively to restrict the size of the answer set. Further, it is not rare to observe a mismatch between the vocabulary used in the text of Web pages and the terms used to compose the Web queries. The combination of these two features might lead to irrelevant query results, particularly in the case of more specific queries composed of three or more terms. To deal with this problem we propose a new technique for automatically structuring Web queries as a set of smaller subqueries. To select representative subqueries we use information on their distributions in the document collection. This can be adequately modeled using the concept of maximal termsets derived from the formalism of association rules theory. Experimentation shows that our technique leads to improved results. For the TREC-8 test collection, for instance, our technique led to gains in average precision of roughly 28% with regard to a BM25 ranking formula.

Capacity-Constrained Query Formulation

“…As a baseline we adapt the maximal termset approach by Pôssas et al [3], but we do not use GENMAX as a subroutine to enlarge promising keyphrase subsets. Instead, we adopt {w1, w2} {w1, w5} {w2, w4} {w2, w5} {w3, w5} {w1,w2,w3} {w1,w2,w4} {w1,w2,w5} {w1,w3,w4} {w1,w3,w5} {w1,w4,w5} {w2,w3,w4} {w2,w3,w5} {w2,w4,w5} {w1, w2, w3, w4} {w1, w2, w3, w5} {w1, w2, w4, w5} {w1, w3, w4, w5} {w2, w3, w4, w5} {w3, w4} Table 1's example scenario.…”

“…Unfortunately, it is straightforward to construct situations in which the approach fails although adequate queries exist. A more involved maximal termset query formulation method is proposed by Pôssas et al [3]; we use an adapted version as our baseline.…”

“…For the query formulation problem we develop a heuristic search strategy based on cooccurrence probabilities. Compared to the maximal termset strategy [3], which can be considered as the most sensible non-heuristic baseline, our expected savings are on average 50% when queries for 9 or 10 phrases are to be constructed. …”

Search Strategies for Keyword-based Queries

“…Shapiro and Taksa [11] suggest a rather simple open end query formulation approach for which it is straightforward to find situations where the approach fails although appropriate queries exist. A more involved maximal termset method is proposed by Pôssas et al [10]. However, both approaches focus on finding a whole set of queries instead of just one maximum query and neither Shapiro and Taksa …”

Candidate Document Retrieval for Web-Scale Text Reuse Detection

“…The retrieved web documents can then be delivered to a text reuse detection system for an in-depth analysis. We focus on the query formulation problem as the crucial first step in the detection process and present a new query formulation strategy that achieves convincing results: compared to a maximal termset query formulation strategy [10,14], which is the most sensible non-heuristic baseline, we save on average 70% of the queries in realistic experiments. With respect to the candidate documents' quality, our heuristic retrieves documents that are, on average, more similar to the given document than the results of previously published query formulation strategies [4,8].…”