“…Figure 14 shows the detection results obtained by the GRU model when the number of FBG sensors is seven. As shown in the figure, the proposed model capable of detecting the Bragg wavelength of each FBG, even when the spectra of FBGs are partially overlapped (see strain steps 7,11,13,16,18,21,24,29,31,36,38,43,45,49,51, 56 and 58) and fully overlapped (see strain step 8, 12, 17, 23, 30, 37, 44, 50 and 57). Moreover, the average RMS errors of our proposed GRU model for the four different cases, such as 3-FBG, 5-FBG, 7-FBG, and 10-FBG, are summarized in Table 4.…”