**5. Conclusions**

This study developed a performance evaluation and LCC analysis model and used the model to evaluate the performance and analyze the LCC of a GEWPro, which was developed to improve the problems related to conventional exterior wall painting work. The results of the study are as follows:


GEWPro showed that the present net profit, B/C ratio, break-even point, and annual construction cost saving rate was \$430,404, 6.39, 1.36 years, and 12.2%, which showed that the use of GEWPro was economically more efficient and viable compared to the conventional method.

(4) According to sensitivity analysis, which was performed to improve the reliability of a performance evaluation and LCC analysis of GEWPro, among the six major variables identified for sensitivity analysis, four variables (preparation and installation work process, GEWPro initial cost, maintenance cost, and interest rate) had a very low impact on the economic efficiency of GEWPro within the set sensitivity range. To secure the economic efficiency of using GEWPro over the conventional method, however, the speed of the painting work process should be greater than 5 m/min (currently, 6.2 m/min), whereas the disassembly and horizontal moving work should be done within 13 min/process (currently, 8.4 min/process).

Regarding economic analysis, although this study only considered the quantitative resources and expenses, such as equipment and labor cost, it is expected that the economic reliability and validity of the automated method would be furthered if additional consideration is given to qualitative factors, such as safety enhancement and uniformity in the quality of work brought by the automated method. Finally, authors need to consistently experiment and verify the sustainable applicability and operational stability of GEWPro on construction sites. For this, a number of field trials and case studies should be carried out in the near future.

**Acknowledgments:** This work was supported by INHA UNIVERSITY Research Grant.

**Author Contributions:** Dong-Jun Yeom conceived the idea for this study and wrote the manuscript. Eun-Ji Na and Mi-Young Lee designed the early methodology. Yoo-Jun Kim contributed to some of the LCC analysis and editing the paper. Young-Suk Kim and Chung-Suk Cho conceived the idea, supervised the research, and revised the manuscript. All authors read and approved the final manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.
