Find reappearing pattern in the signal
Vladimir: You're trying to detect a certain sample pattern (a certain sequence of sample values) within a longer discrete sequence of input samples. This sounds liked a "matched filter" problem to me. If the pattern of samples you're trying to detect is the samples in the red shaded region of your diagram then performing convolution seems like a smart thing to try first before you explore more exotic signal detection algorithms. By convolution I mean an implementation where you pass your long input sequence of values through a tapped-delay line FIR filter. But be careful! You must make sure that the coefficients of the tapped-delay line filter are a "flipped in time" (reversed in time order) version of the sequence you're trying to detect.