  This case study is an update-in-place refactoring transformation on UML class
diagrams. Its aim is to remove clones of attributes from a class diagram, and
to identify new classes which abstract groups of classes that share common data
features.
  It is used as one of a general collection of transformations (such as the
removal of redundant inheritance, or multiple inheritance) which aim to improve
the quality of a specification or design level class diagram.
  The transformation is a typical example of a model refactoring, and
illustrates the issues involved in such transformations.
