        0,&amp;x_{jk}\leq 0\\
        \mu_{\triangle_{\downarrow}}(x_{jk}),&amp;\mathrm{min}\leq x_{jk}\leq\mathrm{m}\\
        \mu_{\triangle_{\uparrow}}(x_{jk}),&amp;\mathrm{m}&lt;x_{jk}&lt;\mathrm{max}\\
        0,&amp;x_{jk}\geq \mathrm{max}
    \end{cases}
\end{equation}\]</span> where <span class="math inline">\(\mathrm{m}:= \frac{v_{i}^{*}+v_{i+1}^*}{2}\)</span> such that <span class="math inline">\(v_i^*&lt;\mathrm{m}&lt;v_{i+1}^*\)</span>, and <span class="math inline">\(v_i^{*}\)</span> and <span 