Acta Numerica 2019: Volume 28

1. Solving inverse problems using data-driven models Simon Arridge, Peter Maass, Ozan Öktem and Carola-Bibiane Schönlieb; 2. Numerical analysis of hemivariational inequalities in contact mechanics Weimin Han and Mircea Sofonea; 3. Derivative-free optimization methods Jeffrey Larson, Matt Menickelly and Stefan M. Wild; 4. Numerical methods for Kohn–Sham density functional theory Lin Lin, Jianfeng Lu and Lexing Ying; 5. Approximation algorithms in combinatorial scientific computing Alex Pothen, S. M. Ferdous and Fredrik Manne; 6. Data assimilation: the Schrödinger perspective Sebastian Reich.