%T Computing Dense Clusters On-line for Information Organization %A J. Aslam %A K. Pelekhov %A Daniela Rus %R Technical Report PCS-TR97-324 %I Dartmouth College, Computer Science %C Hanover, NH %D October 1997 %U http://www.cs.dartmouth.edu/reports/TR97-324.ps.Z %X We present and analyze the off-line star algorithm for clustering static information systems and the on-line star algorithm for clustering dynamic information systems. These algorithms partition a document collection into a number of clusters that is naturally induced by the collection. We show a lower bound on the accuracy of the clusters produced by these algorithms. We use the random graph model to show that both star algorithms produce correct clusters in time Theta(V + E). Finally, we provide data from extensive experiments. %Z Submitted to the 1998 SIGIR Conference.