Using hybrid methods and `core documents' for the representation of clusters and topics. The astronomy dataset

Based on a dataset on Astronomy & Astrophysics a hybrid cluster analysis has been conducted. Hybrid clustering was based on a combination of bibliographic coupling and textual similarities using Louvain method at two resolution levels. The procedure resulted in seven and thirteen clusters, respectively. The statistics reflect a high quality of classification. For labelling and interpreting clusters, core documents are used. The results of these two scenarios are presented, discussed and compared with each other. The two scenarios clearly result in hierarchical structures that are analysed with the help of a concordance table. Furthermore, the core documents help depict the internal structure of the complete network and the clusters. This work has been done as part of the international project ‘Measuring the Diversity of Research’ and in the framework a special workshop on the comparative analysis of algorithms for the identification of topics in science organised in Berlin in August 2014.status: publishe