1Library of Tongji University, Tongji University, Siping Street 1239, Shanghai, 200092, China. E-mail: yxliu@lib.tongji.edu.cn
2Institute for Education and Information Sciences, IBW, University of Antwerp, Venusstraat 35, Antwerp, B-2000, Belgium. E-mail: raf.guns@ua.ac.be
3Institute for Education and Information Sciences, IBW, University of Antwerp, Venusstraat 35, Antwerp, B-2000, Belgium. E-mail: ronald.rousseau@ua.ac.be
4Faculty of Engineering Technology, VIVES-KHBO (Association KU Leuven), Zeedijk 101, Oostende, B-8400, Belgium
5KU Leuven, Leuven B-3000, Belgium
Online published on 22 October, 2013.
A binary tree is used as a model for a hierarchical structure. All nodes situated at the same height are assumed to form a group. The global and local Q-value, being measures for the extent to which a node plays a bridging function between groups, are determined. For the global Q-value this is can be done in two ways: a direct one and one via a recursion relation.
Global Q-measures, Local Q-measures, Rooted trees