Nothing real.
I know only of a Generalmajor der Reserve Friedrich-Wilhelm Dernen. Born. 15 Feb 1884 in Cologne. Died 15 Feb 1967 in Bad Homburg on the Höhe.
He's the man who got the PlM on the 29th August 1918 as a Lt.d.R. but nothing to do with the Ulan Reg however.
Perhaps a relative ?