  This paper approximates simulation models by B-splines with a penalty on
high-order finite differences of the coefficients of adjacent B-splines. The
penalty prevents overfitting. The simulation output is assumed to be
nonnegative. The nonnegative spline simulation metamodel is casted as a
second-order cone programming model, which can be solved efficiently by modern
optimization techniques. The method is implemented in MATLAB/GNU Octave.
