Russell C. Swan

Extracting significant time varying features from text

We propose a simple statistical model for the frequency of occurrence of features in a stream of text. Adoption of this model allows us to use classical significance tests to filter the stream for interesting events. We tested the model by building a system and running it on a news corpus. By a subjective evaluation, the system worked remarkably well: almost all of the groups of identified tokens corresponded to news stories and were appropriately placed in time. A preliminary objective evaluation was also used to measure the quality of the system and it showed some of the weaknesses and the power of our approach.

Evaluating combinations of ranked lists and visualizations of inter-document similarity

We are interested in how ideas from document clustering can be used to improve the retrieval accuracy of ranked lists in interactive systems. In particular, we are interested in ways to evaluate the effectiveness of such systems to decide how they might best be constructed. In this study, we construct and evaluate systems that present the user with ranked lists and a visualization of inter-document similarities. We first carry out a user study to evaluate the clustering/ranked list combination on instance-oriented retrieval, the task of the TREC-6 Interactive Track. We find that although users generally prefer the combination, they are not able to use it to improve effectiveness. In the second half of this study, we develop and evaluate an approach that more directly combines the ranked list with information from inter-document similarities. Using the TREC collections and relevance judgments, we show that it is possible to realize substantial improvements in effectiveness by doing so, and that although users can use the combined information effectively, the system can provide hints that substantially improve on the users solo effort. The resulting approach shares much in common with an interactive application of incremental relevance feedback. Throughout this study, we illustrate our work using two prototype systems constructed for these evaluations. The first, AspInQuery, is a classic information retrieval system augmented with a specialized tool for recording information about instances of relevance. The other system, Lighthouse, is a Web-based application that combines a ranked list with a portrayal of inter-document similarity. Lighthouse can work with collections such as TREC, as well as the results of Web search engines.

TimeMine (demonstration session): visualizing automatically constructed timelines

A screen shot from the TlmeMine system. The screenshot shows the top 5 stories between the end of February and mid May. Noun phrases related to the Jonesboro school shooting are displayed, and a histogram of the usage of the phrase westside mlddle schoolis displayed, along with a list of the three documents on March 29 containing that phrase. 1 Introduction We are interested in novel methods of displaying and organizing information to increase its accessibility and value. We have specifically been investigating the use of time as an organizing feature for information. Our research[2,3] has focused on using the statistical properties of term distributions within a corpus to select features for display in a timeline. We have built a prototype system called TimeMine.