## 3 Results
### Structural and Thematic Development
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{5}{c}{**Period 1997–2015**} \\ \hline
**Denomination** & **Works** & **h-Index** & **g-Index** & **hg-Index** & **q2-Index** & **Citations** \\ \hline Development & 3 & 3 & 3 & 3 & 7.75 & 56 \\ Tailored optical fibers & 3 & 3 & 3 & 3 & 7.75 & 56 \\ Pedagogy & 5 & 2 & 3 & 2.45 & 4.9 & 24 \\ Teachers & 4 & 4 & 4 & 4 & 9.8 & 92 \\ Usability & 5 & 3 & 3 & 3 & 7.55 & 51 \\ Instruction & 5 & 3 & 3 & 3 & 7.35 & 54 \\ Virtual environments & 12 & 7 & 9 & 7.94 & 18.52 & 492 \\ Visualization & 9 & 4 & 7 & 5.29 & 7.75 & 57 \\ Mixed reality & 4 & 1 & 2 & 1.41 & 4.69 & 23 \\ System & 5 & 3 & 4 & 3.46 & 9.17 & 102 \\ Social media & 3 & 2 & 2 & 2 & 2.45 & 8 \\ Online education & 2 & 2 & 2 & 2 & 6.48 & 30 \\ Gamification & 3 & 1 & 2 & 1.41 & 3.46 & 13 \\ Context Aware & 2 & 1 & 1 & 1 & 2.24 & 5 \\ Pattern recognition & 2 & 1 & 1 & 1 & 1 & 1 \\
3D modeling & 3 & 2 & 3 & 2.45 & 8.12 & 42 \\ \hline \multicolumn{5}{c}{**Period 2016–2019**} \\ \hline Technology acceptance & 6 & 2 & 3 & 2.45 & 3.46 & 12 \\ Improvement & 6 & 2 & 2 & 2 & 2.45 & 7 \\ Spatial orientation & 4 & 2 & 3 & 2.45 & 5.48 & 32 \\ Instruction & 5 & 3 & 3 & 3 & 13.64 & 173 \\ University & 6 & 1 & 1 & 1 & 1 & 2 \\ Mobile & 12 & 2 & 3 & 2.45 & 3.74 & 15 \\ Higher education & 68 & 8 & 16 & 11.31 & 11.31 & 294 \\ Anatomy & 5 & 2 & 2 & 2 & 6.48 & 23 \\ Usability & 5 & 2 & 2 & 2 & 3.46 & 8 \\ Framework & 6 & 3 & 6 & 4.24 & 4.58 & 82 \\ Virtual reality & 21 & 4 & 5 & 4.47 & 8 & 51 \\ Attitude & 4 & 2 & 3 & 2.45 & 2.83 & 10 \\ Blended learning & 4 & 0 & 0 & 0 & 0 & 0 \\ Internet of things & 2 & 0 & 0 & 0 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Thematic performance. technology, education, and acceptance of the user. This period also highlights \"virtual environments\", which, although a basic and cross-cutting theme, is of great relevance to the scientific community, due to its high h-index. In the same way, during this period, \"3D modeling\" themes predominate. \"3D modeling\" focuses on photography and user interface. This category also includes \"gamification\", which is aimed at technological, mobile, and gaming information; \"context aware\", which is focused on image detection and mobile applications; \"pattern recognition\", focused on 3D and mathematics; and \"systems\", associated with educational research, open streets, mobile learning, human-computer interactions, and operational and educational engineering. This last topic belongs to an unknown profile, since its location in the diagram defines it as an emerging or disappearing theme. In the second period (Figure 5), the thematic engines include \"technology acceptance\", which refers to supports, experimental learning, sensor networks, remote laboratories, meta-analysis, mobile augmented reality, information, and students; \"framework\", which relates to building modeling, collaboration, context knowledge, simulation, strategies, industry 4.0, big data, and impact; \"university\", which is associated with development, skills, applications, English, acceptance, teaching-oriented technology, and gender; \"instruction\", which is linked to learning systems, designs, spatial capacity, performance, educational technology, education sciences, and cognitive load; \"improve\", focused on teaching, construction, youth, system, mobile technology, university students, interactive learning environments, and opportunity strategies; \"mobile\", which is related to architecture, ubiquitous learning, museums, technology, models, technological learning, and tools; and \"higher education\", which focuses on information and communication technologies, mobile learning, user acceptance, interface, perception, plans, flipped classrooms, and augmented reality. In addition, given its location as an emerging or missed topic, \"anatomy\", which is related to mathematics, accepted technological models, interactions, devices, visualization, pedagogy, learning, and teacher training, should be kept  
Figure 4: Strategic diagram by h-index: 1997–2015.