Institute for Systems Theory and Automatic Control, University of Stuttgart, 70569 Stuttgart, Germany, Department of Statistical Science, University College, London WC1E 6BT, UK and Department of Statistics, University of Warwick, Coventry CV4 7AL, UK.|Institute for Systems Theory and Automatic Control, University of Stuttgart, 70569 Stuttgart, Germany, Department of Statistical Science, University College, London WC1E 6BT, UK and Department of Statistics, University of Warwick, Coventry CV4 7AL, UK.|Institute for Systems Theory and Automatic Control, University of Stuttgart, 70569 Stuttgart, Germany, Department of Statistical Science, University College, London WC1E 6BT, UK and Department of Statistics, University of Warwick, Coventry CV4 7AL, UK.|Institute for Systems Theory and Automatic Control, University of Stuttgart, 70569 Stuttgart, Germany, Department of Statistical Science, University College, London WC1E 6BT, UK and Department of Statistics, University of Warwick, Coventry CV4 7AL, UK.