# A Study on Finding Partners through Patent Network Analysis of UAM (Urban Air Mobility)
## 3 Analysis
### Quantitative Analysis  
#### 3.2.1 Number of Patents  
The number of patent applications filed by 19 of the world's leading eVTOL companies related to UAM is shown in Table 5. Among the 19 companies, most of the eVTOL companies--except for BOEING, AIRBUS, and BELL--were pursuing passive patent strategies, and it was confirmed that 3 companies were in leading positions for most of the areas. In the comparison by country, the US, Europe, China, Japan, and Korea appeared to be leading in that order. Most companies applied for key patents in the US, but Ehang filed most patents in its home country, China. In the above analysis, it was judged that it was meaningful to derive a partner company after analyzing the patents of the 3 leading companies that are actively applying for patents, so a patent analysis was conducted with a focus on these 3 companies. As a result of examining the joint application patents of the other companies, it was found that these companies' research focused on developing their  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Category** & **Indicators** & **Meaning** & **Formula** \\ \hline \multirow{3}{*}{Quantitative} & Number of & \multirow{3}{*}{Patents} & \multirow{3}{*}{Patent Activity} & \multirow{3}{*}{-} \\  & Patents & & \\ \cline{1-1}  & \multirow{3}{*}{ActivityIndex} & Relative & \multirow{3}{*}{A. I =} & \multicolumn{1}{c}{Number of specific applications in specific technical fields} \\ \cline{1-1}  & & & \multicolumn{1}{c}{Number of specific applications} \\ \cline{1-1}  & \multirow{3}{*}{Cites Per Patent} & Citation Index, & \multirow{3}{*}{\(\text{CPP}=\dfrac{\text{Number of citations}}{\text{Total number of registrations}}\)} \\ \cline{1-1}  & & Influence & \\ \cline{1-1}  & \multirow{3}{*}{Patent Impact Index} & Relative & \multirow{3}{*}{\(\text{PII}=\dfrac{\text{Citation fee of a specific applicent in a specific technical field}}{\text{Total citation cost}}\)} \\ \cline{1-1}  & & Influence & \\ \cline{1-1}  & \multirow{3}{*}{Technology Strength} & \multirow{3}{*}{Technology Strength} & \multirow{3}{*}{Technology} & \multirow{3}{*}{\(\text{TS}=\text{number of patents x Current Impact Index}\)} \\ \cline  
own aircraft rather than on joint research, which led to the conclusion that these cases were not suitable for research on finding partners. Table 6 shows that the total number of UAM-related patents and joint applications of BOEING, AIRBBUS, and BELL, the number of joint applications, and the number of patents by technology are as follows. Comparing the number of co-applicants also provides some insight into the company's R&D strategy. As shown in Figure 6, in the case of BOEING, joint applications were made due to joint research in 519 (3%) of the 16,834 patents, while in the case of AIRBUS, 1343 (8%) out of 16,033 patents were processed as joint applications. In the case of BELL, only 46 (2%) of the 2148 patents were identified as joint research. In joint research analysis, the presence or absence of joint research had both advantages and disadvantages. In the case of BOEING and BELL, it can be observed that only a minimal amount of technology is developed through external collaboration, and thus, the company holds ownership for most of the technology. If you compare this to the automotive industry, it would be like a company such as Tesla that controls all systems in the form of technological development and creates innovation through cooperative control. In contrast, for AIRBUS, traces of collaboration were found in 1343 patents, which had some similarity to existing automotive OEMs