# The Role of Industry 4.0 and Circular Economy for Sustainable Operations: The Case of Bike Industry
## 3 Model Formulation
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multirow{2}{*}{**Change (\%)**} & \multicolumn{5}{c}{**Optimal Solutions**} \\ \cline{3-6}  & & \(\mathbf{p^{*}}\) & \(\mathbf{t_{1}^{*}}\) & \(\mathbf{t_{4}^{*}}\) & \(\mathbf{AC(p^{*},\mathbf{t_{1}^{*}},\mathbf{t_{2}^{*}})}\) \\ \hline \multirow{4}{*}{\(p_{1}\)} & 50\% & 125.399 & 3.0843 & 4.1282 & 6621.91 \\  & 25\% & 393.338 & 2.9481 & 3.3552 & 6575.74 \\  & \(-\)25\% & 516.398 & 0.7995 & 3.0995 & 6483.41 \\  & \(-\)50\% & 553.813 & 0.6426 & 2.7981 & 6437.24 \\ \hline \multirow{4}{*}{\(h_{f}\)} & 50\% & 199.344 & 0.9985 & 5.7014 & 6623.82 \\  & 25\% & 298.280 & 1.0294 & 4.1272 & 6576.71 \\  & \(-\)25\% & 530.233 & 1.1246 & 3.1402 & 6524.14 \\  & \(-\)50\% & 539.372 & 1.9993 & 3.0511 & 6515.32 \\ \hline \multirow{4}{*}{\(h_{e}\)} & 50\% & 157.571 & 1.0023 & 1.4074 & 6786.60 \\  & 25\% & 160.434 & 1.0748 & 3.3701 & 6657.23 \\ \cline{1-1}  & \(-\)25\% & 526.985 & 1.0975 & 4.3503 & 6400.21 \\ \cline{1-1}  & \(-\)50\% & 541.887 & 1.1898 & 6.1973 & 6398.50 \\ \hline \multirow{4}{*}{\(h_{g}\)} & 50\% & 71.7052 & 0.9946 & 1.9803 & 6476.52 \\  & 25\% & 191.372 & 1.0172 & 2.3185 & 6503.91 \\ \cline{1-1}  & \(-\)25\% & 446.400 & 1.0929 & 8.9382 & 6553.54 \\ \cline{1-1}  & \(-\)50\% & 612.191 & 1.9649 & 9.6048 & 6579.21 \\ \hline \multirow{4}{*}{\(c_{pf}\)} & 50\% & 119.715 & 1.0010 & 3.1432 & 6532.77 \\  & 25\% & 166.646 & 1.0272 & 3.6996 & 6529.47 \\ \cline{1-1}  & \(-\)25\% & 519.728 & 2.9220 & 4.1268 & 6526.28 \\ \cline{1-1}  & \(-\)50\% & 529.365 & 3.0534 & 5.0842 & 6524.67 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Effect of changes in various parameters of the model for example 2. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multirow{2}{*}{**Change (\%)**} & \multicolumn{5}{c}{**Optimal Solutions**} \\ \cline{3-6}  & & \(\mathbf{p^{*}}\) & \(\mathbf{t_{1}^{*}}\) & \(\mathbf{t_{4}^{*}}\) & \(\mathbf{AC(p^{*},\mathbf{t_{1}^{*}},\mathbf{t_{2}^{*}})}\) \\ \hline \multirow{4}{*}{\(\theta_{f}\)} & 50\% & 398.751 & 1.2106 & 3.0722 & 2963.04 \\  & 25\% & 398.721 & 1.2107 & 3.0712 & 2963.04 \\  & \(-\)25\% & 398.681 & 1.2116 & 3.0691 & 2963.03 \\  & \(-\)50\% & 398.661 & 1.2118 & 3.0682 & 2963.01 \\ \hline \multirow{4}{*}{\(r_{e}\)} & 50\% & 399.891 & 1.2108 & 3.0901 & 2963.05 \\  & 25\% & 399.822 & 1.2109 & 3.0802 & 2963.05 \\  & \(-\)25\% & 397.401 & 1.2114 & 3.0603 & 2963.01 \\  & \(-\)50\% & 396.301 & 1.2115 & 3.0401 & 2962.99 \\ \hline \multirow{4}{*}{\(r_{g}\)} & 50\% & 398.901 & 1.2107 & 3.0712 & 2963.12 \\  & 25\% & 398.821 & 1.2109 & 3.0708 & 2963.09 \\  & \(-\)25\% & 398.711 & 1.2115 & 3.0698 & 2963.04 \\  & \(-\)50\% & 398.612 & 2.2118 & 3.0691 & 2963.01 \\ \hline \multirow{4}{*}{\(\alpha\)} & 50\% & 398.691 & 1.2116 & 3.0691 & 2973.04 \\  & 25\% & 398.692 & 1.2114 & 3.0697 & 2963.04 \\  & \(-\)25\% & 398.705 & 1.2109 & 3.0705 & 2953.04 \\  & \(-\)50\% & 398.708 & 1.2106 & 3.0709 & 2943.04 \\ \hline \multirow{4}{*}{\(\beta\)} & 50\% & 402.145 & 1.1812 & 6.1934 & 3213.26 \\  & 25\% & 401.178 & 1.1934 & 4.1980 & 3014.16 \\  & \(-\)25\% & 396.013 & 1.2319 & 2.1982 & 2960.15 \\  & \(-\)50\% & 392.124 & 1.2681 & 1.7841 & 2958.11 \\ \hline \multirow{4}{*}{\(\gamma\)} & 50\% & 412.013 & 1.2601 & 3.2146 & 5019.21 \\  & 25\% & 401.456 & 1.2213 & 3.1561 & 4311.09 \\ \cline{1-1}  & \(-\)25\% & 381.781 & 1.1927 & 2.9811 & 1865.19 \\ \cline{1-1}  & \(-\)50\% & 361.890 & 1.1789 & 2.8157 & 1618.01 \\ \hline \hline \end{tabular}
\end{table}