Assessing the behavior and performance of a supervised term-weighting technique for topic-based retrieval

摘要

Topic-based retrieval is the task of seeking and retrieving material related to a topic of interest. This task involves two subtasks: selecting query terms and ranking the retrieved results. Supervised approaches to assess the importance of a term in a topic or class have demonstrated to be effective for guiding the query-term selection subtask. This article analyzes and evaluates FDD_β, a supervised term-weighting scheme that can be applied for query-term selection in topic-based retrieval. FDD_β weights terms based on two factors representing the descriptive and discriminating power of the terms with respect to the given topic. It then combines these two factor through the use of an adjustable parameter that allows to favor different aspects of retrieval, such as precision, recall or a balance between both. Previous preliminary studies have demonstrated the potential of FDD_β to identify useful query terms. However, preceding studies have limited the analysis to a single domain represented by a single data set with binary categories and have not compared FDD_β to other recently formulated term-weighting techniques. The contributions of this article are the following: (1) it presents an extensive analysis of the behavior of FDD_β as a function of its adjustable parameter; (2) it compares FDD_β against eighteen traditional and state-of-the-art weighting scheme; (3) it evaluates the performance of disjunctive queries built by combining terms selected using the analyzed methods; (4) it makes a full data set and the full code publicly available to replicate the reported analysis and foster future research in the area. The analysis and evaluations are performed on three data sets: two well-known text data sets, namely 20 Newsgroups and Reuters-21578, and the newly released data set. It is possible to conclude that despite its simplicity, FDD_β is competitive with state-of-the-art methods and has the important advantage of offering flexibility at the moment of adapting to specific task goals. The results also demonstrate that FDD_β offers a useful mechanism to explore different approaches to build complex queries.