Membership functions for dirt

Membership functions for grease

$\begin{array}{l}{\mu }_{SD}\left(x\right)=\frac{50-x}{50},0\le x\le 50\\ {\mu }_{MD}\left(x\right)=\{\begin{array}{l}\frac{x}{50},0\le x\le 50\\ \frac{100-x}{50},50\le x\le 100\end{array}\\ {\mu }_{LD}\left(x\right)=\frac{x-50}{50},50\le x\le 100\end{array}$

$\begin{array}{l}{\mu }_{SG}\left(y\right)=\frac{50-y}{50},0\le y\le 50\\ {\mu }_{MG}\left(y\right)=\{\begin{array}{l}\frac{y}{50},0\le y\le 50\\ \frac{100-y}{50},50\le y\le 100\end{array}\\ {\mu }_{LG}\left(y\right)=\frac{y-50}{50},50\le y\le 100\end{array}$