@TechReport{	  it:2010-016,
  author	= {A. Rensfelt and T. S{\"o}derstr{\"o}m},
  title		= {Parametric Identification of Complex Modulus},
  institution	= {Department of Information Technology, Uppsala University},
  department	= {Division of Systems and Control},
  year		= {2010},
  number	= {2010-016},
  month		= jun,
  abstract	= {This report treats three different approaches to
		  parametric identification of the complex modulus of a
		  viscoelastic material. In the first approach, a
		  nonparametric estimate is used to fit the parametric model,
		  while in the other two the model is fitted directly from
		  data. In all three cases, theoretical expressions for the
		  accuracy of the estimate are derived under the assumption
		  that the measurement noise is white and that the
		  signal-to-noise ratio is large. The expressions are
		  validated against both simulated and experimental data. In
		  the case of experimental data it is seen that the
		  theoretical expression severely underestimates the variance
		  of the identified parameters, and one of the expressions is
		  therefore modified to cover the case of correlated noise
		  with much better agreement as a result.}
}