## 4 Results
### Q1: What Type of Research Was Conducted?  
To answer this question, the classification scheme proposed by [PERSON] et al. [PERSON] et al. (2019), as used, which defines six types of research according to their characteristics: (i) validation, studies where the investigated techniques are novel and have not yet been implemented in practice, such as experiments; (ii) evaluation, studies where the techniques are implemented and evaluated; (iii) solution, studies where a solution to a problem is proposed, which may be either novel or a significant extension of an existing technique; (iv) philosophical studies, studies that describe a new perspective on existing things by structuring the field taxonomically or within a conceptual framework; (v) opinion studies, studies that express a personal opinion on whether a technique is good or bad, or how things should be done, and finally; (vi) experience studies, studies that explain what and how something has  
Figure 5: Score obtained in the criteria of relevance and pertinence.  
been executed in practice based on personal experiences. Figure 5 presents the type of research (see right quadrant) conducted for each primary study. It was observed that 43% of the studies are evaluations (S3, S7, S8, S10, S11, S12, S15, S16, S19, S22, S24, and S25), 28.6% are validations (S2, S4, S5, S9, S20, S21, S23, and S28), and the remaining 28.6% are philosophical studies (S1, S6, S13, S14, S17, S18, S26, and S27). The left quadrant of Figure 7 also presents the grouping of the distribution of solution types, which is addressed in the next section.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{5}{c}{**Research Questions**} \\ \hline
**Articles** & **RQ1** & **RQ2** & **RQ3** & **RQ4** & **RQ5** \\ \hline S1 & 1 & 1 & 1 & 0 & 1 \\ \hline S2 & 1 & 1 & 1 & 0 & 0 \\ \hline S3 & 1 & 1 & 1 & 0 & 0 \\ \hline S4 & 1 & 1 & 1 & 1 & 0 \\ \hline S5 & 1 & 1 & 1 & 1 & 1 \\ \hline S6 & 1 & 1 & 1 & 1 & 0 \\ \hline S7 & 1 & 0 & 0 & 0 & 0 \\ \hline S8 & 1 & 1 & 1 & 1 & 1 \\ \hline S9 & 1 & 0 & 0 & 0 & 0 \\ \hline S10 & 1 & 1 & 1 & 0 & 0 \\ \hline S11 & 1 & 1 & 0 & 0 & 0 \\ \hline S12 & 1 & 1 & 0 & 0 & 0 \\ \hline S13 & 1 & 1 & 1 & 1 & 1 \\ \hline S14 & 1 & 1 & 1 & 1 & 0 \\ \hline S15 & 1 & 1 & 1 & 0 & 0 \\ \hline S16 & 1 & 1 & 1 & 1 & 0 \\ \hline S17 & 1 & 1 & 0 & 0 & 1 \\ \hline S18 & 1 & 1 & 1 & 1 & 1 \\ \hline S19 & 1 & 1 & 1 & 0 & 0 \\ \hline S20 & 1 & 0 & 0 & 0 & 0 \\ \hline S21 & 1 & 1 & 1 & 0 & 1 \\ \hline S22 & 1 & 0 & 0 & 0 & 0 \\ \hline S23 & 1 & 1 & 1 & 1 & 1 \\ \hline S24 & 1 & 1 & 1 & 1 & 1 \\ \hline S25 & 1 & 1 & 1 & 1 & 1 \\ \hline S26 & 1 & 1 & 1 & 1 & 1 \\ \hline S27 & 1 & 1 & 1 & 0 & 1 \\ \hline S28 & 1 & 1 & 1 & 1 & 1 \\ \hline Total & 28 & 24 & 21 & 13 & 13 \\ \hline \hline \end{tabular}
\end{table}
Table 10: Compendium of the research questions addressed by each primary study.  
**Main findings (Research Question Q1)**  
The analysis shows that 43% of the studies focus on the evaluation of implemented techniques, 28.6% on the validation of new techniques, and 28.6% on philosophical studies that provide new perspectives. This suggests a significant focus on practical evaluation and conceptual exploration in the area studied.  
Figure 6: Score of the research questions addressed by each primary study.  
Figure 7: Visualization of the solution and research types of the studies in a bubble chart.