\documentclass{paper}
\usepackage{graphicx}
\usepackage[font=scriptsize,labelfont=bf]{caption}
\usepackage{tabularx}
\begin{document}
	


\begin{table}[H]
	\centering
	\resizebox{\textwidth}{!}{%	
		\begin{tabular}{|c|c|}
			\hline
			$J_{1}=\frac{max_{t}\lvert\lvert x_{r}(t)\lvert\lvert}{max_{t}\lvert\lvert x_{r}(t)\lvert\lvert}$ \qquad& $J_{2}=\frac{max_{t}\lvert\lvert a_{r}(t)\lvert\lvert}{max_{t}\lvert\lvert a_{r}(t)\lvert\lvert}$  \qquad \\ \hline
			$J_{3}=\frac{max_{t}\lvert\lvert \sigma_{r}(t)\lvert\lvert}{max_{t}\lvert\lvert \sigma_{r}(t)\lvert\lvert}$ \qquad & $J_{4}=\frac{max_{t}\lvert\lvert \sigma_{r}(t)\lvert\lvert}{max_{t}\lvert\lvert \sigma_{r}(t)\lvert\lvert}$ \qquad\\ \hline
			\multicolumn{2}{c}{$J_{5}=\frac{max_{t}\lvert\lvert U(t)\lvert\lvert}{W}$}  
			\\ 	 \hline                                                                                                                                                                                                                                                                                                                                                                                                                                   
		\end{tabular}
	}
\end{table}


\end{document}