@TechReport{	  it:2008-009,
  author	= {Peter Naucl{\'e}r and Torsten S{\"o}derstr{\"o}m},
  title		= {Linear and Nonlinear Regression with Application to
		  Unbalance Estimation},
  institution	= {Department of Information Technology, Uppsala University},
  department	= {Division of Systems and Control},
  year		= {2008},
  number	= {2008-009},
  month		= mar,
  abstract	= {This paper considers estimation of parameters that enters
		  nonlinearly in a regression model. The problem formulation
		  is closely connected to unbal- ance estimation of rotating
		  machinery. The parameter estimation problem can after
		  approximation be formulated as a linear estimation
		  procedure, while neglecting the effects of the disturbing
		  term. Two such estimators are derived. In addition, a third
		  approach that handles the uncertainty in a statistically
		  sound way is presented. The three methods are compared and
		  analyzed with respect to their statistical accuracy. Using
		  the example of unbalance estimation of a separator, the
		  nonlinear approach is shown to outperform the other two.}
}