Xuse manages requirements, use cases & other artefacts that drive software design. Xuse focuses on clear documentation & communication. It defines an XML data model for requirements & use cases with XSLT providing multiple derived views: HTML/SVG/PDF.
Note there is no GUI for entering requirements, however another project (https://sourceforge.net/projects/xguse/) will provide a GUI.
Java package to study a clustering model described in the paper \"Novel Clustering Algorithm Based Upon Games on Evolving Network\" by Q. Li, Z. Chen, Y. He and J-P. Jiang (in arxiv: http://arxiv.org/pdf/0812.5064v1), generalizations and similar issues.