You ask how to make the table nicer. So
- remove all vertical rules that have no usefulness;
- use top alignment, there's no need for vertically center the entries;
- replace rules in the middle with vertical space;
- use
tabularx
in order to fill the text width and don't worry about computing widths.
\documentclass{article}
\usepackage{caption}
\usepackage{booktabs,tabularx}
\begin{document}
\begin{table}[!htp]
\centering
\caption{Semantic models of the OCCR model}
\label{table:semantic models of OCCR model}
%\scriptsize
\begin{tabularx}{\textwidth}{@{} l c X @{}}
\toprule
Models & Symbol & Description \\
\midrule
Assets & AS &
Asset information in the manufacturing domain, such as hardware
(equipment and tooling), software, the human workforce, and enabling
technologies for achieving reconfiguration.
\\
\addlinespace
Capacity model & CM &
A structured representation of manufacturing KPIs that monitor the
performance state on the shop floor focusing on the reconfiguration.
\\
\bottomrule
\end{tabularx}
\end{table}
\end{document}
Why caption
? Because it makes top captions well separated from the table (the standard classes are set up for bottom captions).
The \label
is better placed next to the relevant \caption
.

You can have vertical centering, but I don't recommend it.
\documentclass{article}
\usepackage{caption}
\usepackage{booktabs,tabularx}
\begin{document}
\begin{table}[!htp]
\centering
\caption{Semantic models of the OCCR model}
\label{table:semantic models of OCCR model}
%\scriptsize
\renewcommand{\tabularxcolumn}{m}
\begin{tabularx}{\textwidth}{@{} l c X @{}}
\toprule
Models & Symbol & Description \\
\midrule
Assets & AS &
Asset information in the manufacturing domain, such as hardware
(equipment and tooling), software, the human workforce, and enabling
technologies for achieving reconfiguration.
\\
\addlinespace
Capacity model & CM &
A structured representation of manufacturing KPIs that monitor the
performance state on the shop floor focusing on the reconfiguration.
\\
\bottomrule
\end{tabularx}
\end{table}
\end{document}

By the way, your \tbc
command should be
\newcommand{\tbc}{\mathop{\textstyle\bigcup}}
or the symbol wouldn't have the properties of a math operator as regards to spacing.