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General fractal-discrete scheme for high-frequency lung sound production
L P L De Oliveira1, B E J Bodmann, D Faistauer
1Centro de Ciências Exatas e Tecnológicas, Universidade do Vale do Rio dos Sinos, UNISINOS, São Leopoldo, RS, Brazil.
Abstract:
A general scheme is proposed to explain the observed spectral properties of high-frequency human respiratory sounds in terms of the interaction between the respiratory flux and a bronchial tree of fractal properties. The air flux is treated as composed of discrete decoupled elements while the tree is assumed to have a Cantor-based geometry. According to this model, the affine behavior often observed in the high-frequency (log-log) spectral range is a direct consequence of the fractal geometry of the bronchial tree in both qualitative and quantitative aspects. This strongly indicates that the dynamics underlying the high-frequency sound generation must have at most nondominant couplings between the relevant fluid components.
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