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<Paper uid="N03-2005">
  <Title>Story Link Detection and New Event Detection are Asymmetric</Title>
  <Section position="2" start_page="0" end_page="0" type="intro">
    <SectionTitle>
1 Introduction
</SectionTitle>
    <Paragraph position="0"> Topic Detection and Tracking (TDT) research is sponsored by the DARPA TIDES program. The research has five tasks related to organizing streams of data such as newswire and broadcast news (Wayne, 2000). A link detection (LNK) system detects whether two stories are &amp;quot;linked&amp;quot;, or discuss the same event. A story about a plane crash and another story about the funeral of the crash victims are considered to be linked. In contrast, a story about hurricane Andrew and a story about hurricane Agnes are not linked because they are two different events. A new event detection (NED) system detects when a story discusses a previously unseen event. Link detection is considered to be a core technology for new event detection and the other tasks.</Paragraph>
    <Paragraph position="1"> Several groups are performing research on the TDT tasks of link detection and new event detection (e.g., (Carbonell et al., 2001) (Allan et al., 2000)). In this paper, we compare the link detection and new event detection tasks in an information retrieval framework, examining the criteria for improving a NED system based on a LNK system, and give specific directions for improving each system separately. We also investigate the utility of a number of techniques for improving the systems.</Paragraph>
  </Section>
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