The "...system of constraints"
  This paper proposes that the mathematical relationship between an entropy distribution and its limit offers some new insight into system performance. This relationship is used to quantify variation among the entities of a system, where variation is defined as tolerance, option, specification or implementation variation among the entities of a system. Variation has a significnt and increasing impact on communications system performance. This paper introduces means to identify, quantify and reduce such performance variations. 
Ken Krechmer