“…This representation has been applied in many grouping problems (Handl and Knowles, 2007), but it still suffers the same issues of redundancy and lack of appropriate operators as the former representations. In (Du et al, 2004), a restricted version of the LBA known as the Linear Linkage Encoding (LLE) has been proposed, in which backward links are not allowed and, apart from an ending node, each node has only one node pointing to it. LLE successfully eliminates the redundancy problem that debilitates former representations, and has been applied to a variety of grouping problems such as Bin Packing, Graph Colouring and Timetabling (Ülker et al, 2006;Ülker et al, 2008).…”