“…Smart factory [44,57,58,54,44,59,60,40] 7. Smart maintenance [45,52,44,52,61,62,63,64] This paper fills the gaps in several previous studies regarding comparative studies of several major I4.0 indices or the development of instruments to measure Industry 4.0 readiness, focusing on technological characteristics. [41], information system and technology [7], implementation of the existing I4.0 index [29,34,35], and the I4.0 comparison, which focuses on the degree of readiness [22].…”