## 5 Conclusions  
In this work, a new methodology based the utilization of an optimization algorithm, the micro-GA, fused with SWT for detecting and estimating the natural frequencies and damping ratios values of civil structures in an automatic manner is presented. In order to demonstrate the efficiency of the proposal, two study cases are presented: (1) a benchmark problem, a numerical model selected from the literature with aiming at comparison with other methodologies; and (2) a real-life eight-story building. The results for the numerical simulation show that the presented methodology is effective in detecting and quantifying the modal parameters of structure, since the obtained errors for natural frequencies and damping ratios have a maximum value of 0.5% and 6%, respectively. This is confirmed since the proposed methodology detects all the modal parameters of the benchmark problem with a remarkably improved accuracy, unlike the abovementioned methodologies, indicating that the proposed novel objective functions that involve the use of the correlation, histogram, and envelope, as well as its weights proved to be effective to solve the MPI. It is worth noting that the proposal allows obtaining an error reduction of over 50% compared to the results presented in [11]. Particularly, it should be pointed out that this proposal only uses the envelope in a quantitative way, i.e., to estimate how similar is the proposed signal with the reference one, whereas the work presented in [11] uses the envelope to directly estimate the modal parameters, making necessary the utilization of schemes to smooth the envelope. On the other hand, by means of the micropopulation concept, the proposal also demonstrated to be fast as only 80 generations were required to estimate the modal parameters values. In the eight-story building example, the results show that the proposal is efficient for identifying and estimating the ND and DR values of the building using dynamic vibrations, a challenging routine, as the measured signals can be time-varying or transient, as well as noisy, confirming that proposed objective functions are efficient to deal with this task. Additionally, the results show that proposed methodology does not require a previous knowledge of structure or an initial value or specialized calibration for estimating the modal parameters with accuracy unlike the methodology proposed by [PERSON] et al. [53]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Mode (Direction)**} & \multicolumn{4}{c}{**Natural Frequency (Hz)**} \\ \cline{2-5}  & **FEA** & **[PERSON] et al. [53]** & **Methodology Proposed by** & \multirow{2}{*}{**New Methodology**} \\  & & & & **[PERSON] et al. [11]** & \\ \hline
1 & 2.01 & 2.11 & 2.10 & 2.15 \\
2 & 6.49 & 7.00 & 6.98 & 7.03 \\
3 & 12.38 & 12.86 & 12.84 & 12.95 \\
4 & 19.80 & 19.15 & 19.14 & 19.53 \\
5 & 26.46 & 25.89 & 25.90 & 26.17 \\
6 & 34.36 & 33.42 & 33.39 & 34.16 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Estimated natural frequencies and damping ratios of the eight-story steel frame. As a future work, it is necessary to explore the convenience to adapt the proposed methodology to analyze the response of building that have adaptive capabilities, such as smart structures or structures that deal with varying loads. This work was supported in part by the Mexican Council of Science and Technology (CONACyT) by the scholarship 289377 and by the SEP-CONACyT CB-2015/254697 project. The authors appreciate to the National Center for Research on Earthquake Engineering for providing the data of the eight-story building. [PERSON] and [PERSON] conceived and designed the methodology. [PERSON], [PERSON], [PERSON], and [PERSON] performed the experiments and analyzed the obtained results. All authors contributed to the preparation of the manuscript, and [PERSON], [PERSON], and [PERSON] revised the manuscript and provided useful intellectual content. The authors declare no conflict of interest.