Fig. 3From: Spline-based specimen shape optimization for robust material model calibrationBivariate normal distribution associated with variances 1. and 2. and covariance 0.5. Eigenvalues are \(\Lambda _1=0.79\) and \(\Lambda _2=2.21\), associated to eigenvectors \([-0.92, 0.38]\) and [0.38, 0.92]. In black, the ellipse with semi-axes of lenghts \(\sqrt{\Lambda _1}\) and \(\sqrt{\Lambda _2}\)Back to article page