## 4 Conclusions  
This study has investigated stakeholder perspectives on safety issues in collaborative mobile robot environments, with specific insights drawn from a quadruped robot case study. Through comprehensive analysis using both the survey and Delphi methods, several significant conclusions can be drawn.  
First, the study identified critical risk factors in human-robot collaboration through worker surveys. Collision and path deviation emerged as the most significant concerns, accounting for 30-35% and 20-25% of the responses, respectively. Technical issues, including explosion prevention performance and sensor reliability, were also notable concerns (15-20% each). Interestingly, these high levels of risk perception existed even though no actual accidents had occurred, suggesting a gap between perceived and actual risks that need to be addressed.  
The analysis of stakeholder perceptions revealed significant differences among the expert groups. Academic experts consistently provided higher risk assessments, particularly for collision and path deviation (mean risk score 20.0), possibly reflecting their broader theoretical understanding of the potential hazards. In contrast, robot developers showed lower risk assessments, indicating their confidence in the technology's capabilities. Operators emphasized practical safety concerns, particularly regarding explosion prevention, demonstrating how direct workplace experience influences risk perception.  
The practical implications of this research are substantial. Safety policies should incorporate diverse stakeholder perspectives rather than relying on single-group assessments. Training programs need to be customized based on professional background, with academic experts receiving more practical exposure and operators receiving theoretical knowledge. A regular risk perception assessment should be integrated into safety management systems, and mechanisms for inter-stakeholder collaboration are essential for developing comprehensive safety strategies.  
However, this study has several limitations that suggest directions for future research. The small sample size in the expert groups limits result generalizability, indicating the need for larger-scale studies across different industrial settings. Future research should investigate the cultural and organizational factors affecting risk perception and conduct longitudinal studies to track how perceptions evolve with increased quadruped robot deployment.  
In conclusion, these findings provide valuable insights for both researchers and practitioners in the field of collaborative robotics. The successful implementation of mobile robot technology, particularly quadruped robots, requires careful consideration of diverse stakeholder perspectives and the development of inclusive safety management strategies. These variations in risk perception underscore the importance of balancing theoretical knowledge with practical experience in safety planning.  
Conceptualization, E.G.; Methodology, E.G. and J.H.L.; Formal analysis, E.G. and J.S.L.; Investigation, E.G. and S.Y.K.; Resources, H.H.K.; Data curation, E.G.; Writing--original draft, E.G.; Writing--review and editing, J.H.L., H.H.K. and J.Y.L.; Supervision, J.Y.L.; Project administration, J.S.L., H.H.K. and J.Y.L. Funding acquisition, H.H.K. and J.Y.L. All authors have read and agreed to the published version of the manuscript.  
This work was supported by the National Research Foundation of Korea (NRF) grant, funded by the Korean government (MSIT, Education) (No. 2018R1A5A7023490).  
Not applicable.  
The raw data supporting the conclusions of this article will be made available by the authors upon request.  
Conflicts of Interest: Author [PERSON] was employed by SK Hynix Corporation. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.