# A Maturity Model Proposal for Industrial Maintenance and Its Application to the Railway Sector
## 2 Material and Methods
### Document Selection
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{1}{c}{**N\({}^{*}\)**} & \multicolumn{1}{c}{**Ref. Year**} & \multicolumn{1}{c}{**Title**} & \multicolumn{1}{c}{**Doc Type**} & \multicolumn{1}{c}{**Industry**} & \multicolumn{1}{c}{**Maintenance Strategy**} & \multicolumn{1}{c}{**Focus**} & \multicolumn{1}{c}{**Implementation Order**} \\ \hline \multirow{3}{*}{1} & \multirow{3}{*}{[15]} & \multirow{3}{*}{2021} & Developing prescriptive maintenance strategies in the aviation industry based on a discrete-event simulation framework for post-prognostics decision making & Article & Aircraft & Prescriptive & Prescription & Yes \\ \hline \multirow{3}{*}{2} & \multirow{3}{*}{[16]} & \multirow{3}{*}{2021} & Integrated Decision Support Systems (IDSS) & & & & Decision & \\  & & for Dairy Farming: A Discussion on How to Improve Their Sustained Adoption & Article & Farming & Prescriptive & support system & No \\ \hline \multirow{3}{*}{3} & \multirow{3}{*}{[17]} & \multirow{3}{*}{2021} & Business analytics in Industry 4.0: & & & & & \\  & & & A systematic review & & & & & \\ \hline \multirow{3}{*}{4} & \multirow{3}{*}{[18]} & \multirow{3}{*}{2021} & A Two-Stage Data-Driven Spatiotemporal & & & & & \\  & & Analysis to Predict Failure Risk of Urban & & & & & & \\  & & & Sewer Systems Leveraging Machine & & & & & \\  & & & Learning Algorithms & & & & & \\ \hline \multirow{3}{*}{5} & \multirow{3}{*}{[19]} & \multirow{3}{*}{2021} & Lifetime Benefits of Intelligent & & & & & \\  & & & Maintenance: Simulation Modeling & & & & & \\  & & Approach and Industrial Case Study & & & & & \\ \hline \multirow{3}{*}{6} & \multirow{3}{*}{[20]} & \multirow{3}{*}{2021} & A Machine Learning Approach to Enable & & & & Decision & \\  & & Bulk Orders of Critical Spare-Parts in the & & & & & & \\  & & Shipping Industry & & & & & \\ \hline \multirow{3}{*}{7} & \multirow{3}{*}{[21]} & \multirow{3}{*}{2021} & Concept and Economic Evaluation of & & & & & \\  & & Prescriptive Maintenance Strategies for an & & & & & \\  & & Automated Condition Monitoring System & & & & & \\ \hline \multirow{3}{*}{8} & \multirow{3}{*}{[22]} & \multirow{3}{*}{2020} & Predictive maintenance in the Industry 4.0: & & & & & \\  & & & A systematic literature review & & & & \\ \hline \multirow{3}{*}{9} & \multirow{3}{*}{[23]} & \multirow{3}{*}{2020} & Data-Driven Prescriptive Maintenance: & & & & & \\  & & Failure Prediction Using Ensemble Support & & & & & \\  & & Vector Classification for Optimal Process & & & & & \\  & & & and Maintenance Scheduling & & & & \\ \hline \multirow{3}{*}{10} & \multirow{3}{*}{[24]} & \multirow{3}{*}{2020} & Agile asset criticality assessment approach & & & & & \\  & & using decision-making grid & & & & & \\ \hline \multirow{3}{*}{11} & \multirow{3}{*}{[25]} & \multirow{3}{*}{2020} & Developing flexible management strategies & & & & & \\  & & in infrastructure: The sequential expansion & & & & & \\  & & problem for infrastructure analysis (SEPIA) & & & & & \\ \hline \multirow{3}{*}{12} & \multirow{3}{*}{[26]} & \multirow{3}{*}{2020} & Prescriptive Analytics for Swapping Aircraft & & & & & \\  & & Assignments at All Nippon Airways & & & & & \\ \hline \multirow{3}{*}{13} & \multirow{3}{*}{[27]} & \multirow{3}{*}{2019} & A prognostic algorithm to prescribe & & & & & \\  & & improvement measures on & & & & & \\  & & throughput bottlenecks & & & & & \\ \hline \multirow{3}{*}{14} & \multirow{3}{*}{[28]} & \multirow{3}{*}{2020} & Application of NARX neural network for & & & & & \\  & & predicting marine engine & & & & & \\ \cline{1-1}  & & performance parameters & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: List of the analyzed papers. The results obtained show that most of the works analyzed dealt with a specific problem, such as the diagnosis or prognosis of the health condition of the target asset. Those that address the problem in a more general way do not show guidelines for implementation; if they do, it is for a specific sector and a specific problem.