Unit Consistency, Generalized Inverses, and Effective System Design   Methods
  This paper examines the potential role of unit consistency as a system design principle. Unit-consistent generalized matrix inverses and unit-invariant matrix decompositions are derived in support of this principle. Applications of the methods described are illustrated with examples relating to nonlinear system identification and robustness to multiplicative noise for image database retrieval. 
Jeffrey Uhlmann
cs.NA