# Digital Twin Lean Intralogistics: Research Implications
## 4 Results  
### Trend Analysis Results  
In reference to pRQ1, Google Trends was searched to verify global interest in the term \"digital twin\". The research concerned the period from 1 January 2010 to 12 January 2021. The scope of the study covered the whole world. The results are shown in Figure 5. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**RQ** & **Keyword** & **Search Range** & **WoS** & **Scopus** \\ \hline RQ1 & H1 & Z1 & 1432 & 2854 \\  & & Z2 & 711 & 1387 \\ \hline RQ2 & H2 & Z1 & 114 & 210 \\  & & Z2 & 46 & 124 \\ \hline RQ3 & H3 & Z1 & 0 & 17 \\  & & Z2 & 0 & 0 \\ \hline RQ4 & H4 & Z1 & 0 & 0 \\  & & Z2 & 0 & 0 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Quantitative literature review—Research results (as of 12.01.2021). Figure 5: Global extent of interest in the term “digital twin” (concerns the period 1 Jan 2010–12 Jan 2021). According to the data in Figure 5, it is noted that interest in digital twin has clearly increased since 2016 and the growing trend may continue. The greatest interest in the term \"digital twin\", according to Google Trends, occurred in Asia and Europe. The authors link the growing interest in digital twin among Internet users to the birth of the industrial revolution, called the era of the digital revolution Industry 4.0, whose element is digital twin, as mentioned in Section 2 of this article. The authors expressed this relationship in a research question, pRQ2. In order to find answers to pRQ2, the authors examined how trends in interest in the terms \"Industry 4.0\" and \"digital twin\" are evolving. Figure 6 shows the results. The data in Figure 6 clearly indicate that, along with the emergence of interest in Industry 4.0, interest in the term \"digital twin\" also increased, with the highest level of interest recorded in Australia, Europe and the USA. It is also worth noticing that until 2014 interest in digital twin was higher than interest in I4.0. A detailed explanation of this phenomenon may be the subject of other studies. During the last year, the pandemic situation has changed the global trend, so the interest rate in digital twin as well as in I4.0 has been decreasing. However, when it comes to the relationship between digital twin and I4.0, the authors relate growing interest in digital twin, influenced by the development of I4.0, to the fact that the digital revolution somehow \"promoted\" or continues to promote IT solutions that are integral to its development. This may be demonstrated by the growing interest of Internet users in the concept of the IoT, the idea of which lies at the heart of the digital age; digital twin solutions are one of the IoT technologies. Figure 7 shows how interest in these terms is shaped. According to the data in Figure 7, since 2010, the greatest interest among the analyzed trends was related to the Internet of Things, or IoT (these terms mean the same thing, but can be entered in the search engine differently). The greatest interest on a global scale is noted in mostly European countries, as well as in Australia. It is also worth noting that at the time when the IoT reached maximum values according to the Google Trends method, interest in digital twin began to increase. This proves, in the authors' opinion, that Internet users are looking for IT tools and technologies generally called Industry 4.0. Both Digital Twin and IoT are digital technologies that are part of I4.0, but Digital Twin can use IoT (see Figure 3). An increase in IoT possibilities results in an increase in possibilities for monitoring the on-line production process, i.e., an increase in the possibility of reading (collecting) data online and using them directly in Digital Twin. Therefore, in the authors' opinion, one can expect an increased interest in Digital Twin in the coming years as a result of the expansion of the IoT concept. Figure 6: Trends in interest in the terms “Industry 4.0” (red line) and “digital twin” (blue line) (concerns the period from 1 Jan 2010-12 Jan 2021).