Effects of decay and STM capacity on topics quality for Reuter documents. Topics quality is expressed as total match counts (-axis) with respect to decay rate (-axis). Values on the -axis correspond to , the decay rate: a low -axis value indicates rapid decay. Topics quality variations are shown at different STM capacity from 0 to 10, and for the first 5 (triangles) and next 5 (circles) most activated items produced by ReAD. Bas5 and bas10 indicate the upper baseline quality achieved in a nondecaying version of ReAD, respectively, for the first 5 and next 5 topics.