The RRM 2008 model
This model is proposed by Chorus et al. 2008. A key difference
between this model, and the RRM models proposed later on is that
in this model the regret of the considered alternative Ri is only
determined by the maximum regret it receives when compared with
its competitor alternatives.
$$ R_i = \max_{i\neq j}\left \{ \sum_{m=1}^{M}\max \left ( 0,
\beta_m\left [ x_{jm} - x_{im} \right ] \right ) \right \} $$