Cross-linkages in the Concise Columbia Encyclopedia (1989 2nd ed., online version). A set of data relating to 12025 encyclopedia entries and to 9778 cross-references or links was rebinned 10-fold for computational convenience to produce the 1203 times 978 entries by links array used here. The following image shows part of this array, subsequent to row/column permutation to force nonzero values as far as possible onto the diagonal.
Show image of data (0.3 MB)
Now we seek to find the most important "knots" or clusters. The following is a filtered version.
Show image of filtered data (0.3 MB)
mr_detect in.fits out.fits
mr_detect -m 9 in.fits out.fits (poisson few events)
mr_detect -m 9 -w 2 in.fits out.fits (produces ellipses around clusters)
mr_detect -m 9 -w 2 -L 3 -F 5 in.fits out.fits (start and finish scales for cluster detection)
The above figures are from SAOtng.
To probe further
"Computational methods for intelligent information access", M.W. Berry, S.T. Dumais and T.A. Letsche, University of Tennessee, 38 pp., 1997, and other papers.
Image and Data Analysis: The Multiscale Approach, J-L Starck, F Murtagh and A Bijaoui, Cambridge University Press, 1998.