Background: Historically, significant advances in scientific understanding have followed advances in measurement and observation. As the resolving power of an instrument increased, so have gains in the understanding of the phenomena being observed. Modern interactive systems are potentially the new "microscopes" when they are…

Illustrates how various key abstractions of information finding, such as document relevance, a desired number of relevant documents, discouragement, exhaustion, and satisfaction can be modeled using the Petri Net framework. Shows that this model leads naturally to a new approach to collection of user data, and to analysis of transaction logs.…