1. A system, comprising: a model, comprising: a linear portion; and a non-linear portion; wherein the model comprises a representation of a plant or process; wherein the model is operable to receive an input vector comprising one or more inputs, and compute a predicted output vector comprising one or more outputs corresponding to one or more attributes of the plant or process, and wherein the predicted output vector is usable to manage the plant or process; and wherein the non-linear portion comprises a function, wherein for each of the one or more inputs: the function has at most one bend; and as the input respectively approaches positive and negative infinity, the function asymptotically approaches respective lines of constant slope.