Algorithm 1 Frequency-domain airflow modeling ($\mathit{f}$-AFM).

Require: $\mathbf{\theta },\zeta$ 1:for$\ell =0$ to n do 2: $\mathbf{C}\left(\ell \right)=\frac{{\sum }_{j=1}^{n}sin\left(\Delta ({\theta }_j,{\mu }_{\theta })\right)·sin\left(\Delta ({\theta }_{\ell j},{\mu }_{\ell })\right)}{\sqrt{{\sum }_{j=1}^{n}si{n}^2\left(\Delta ({\theta }_j,{\mu }_{\theta })\right)·{\sum }_{j=1}^{n}si{n}^2\left(\Delta ({\theta }_{\ell j},{\mu }_{\ell })\right)}}$ 3: end for 4: $[\mathbf{A},\mathbf{F}]=FFT\left(C\right)$ 5: ${\mathbf{F}}_{\mathbf{o}}=[]$ 6: for all $\mathit{f}\in \mathbf{F}$ do 7: $p\left(O\right|f)=1-\mathcal{N}\left(f\right|{\mu }_A,{\sigma }_A)$ 8: if $p\left(O\right|f)>\zeta$ then 9:  ${\mathbf{F}}_{\mathbf{o}}={\mathbf{F}}_{\mathbf{o}}\cup f$ 10: end if 11: end for 12: ${\sigma }_s=1.06{\sigma }_o{\left(n_o\right)}^{(-1/5)}$ 13: $[{\mathit{f}}_{\mathit{l}},{\mathit{f}}_{\mathit{h}}]=MSA({\mathbf{F}}_{\mathbf{o}},{\sigma }_s)$ 14: return ${\mathit{f}}_{\mathit{l}},{\mathit{f}}_{\mathit{h}}$