Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.1/2255
Título: NARX structures for non-invasive temperature estimation in non-homogeneous media
Autor: Teixeira, C. A.
Pereira, W. C. A.
Ruano, A. E.
Ruano, M. Graça
Palavras-chave: NARX structures
Radial basis functions neural networks
Multi-objective genetic algorithms
Non-invasive temperature estimation
Therapeutic ultrasound
Data: 2007
Editora: IEEE
Citação: Teixeira, C. A.; Pereira, W. C. A.; Ruano, A. E.; Ruano, M. Graca. NARX structures for non-invasive temperature estimation in non-homogeneous media, Trabalho apresentado em 2007 IEEE International Symposium on Intelligent Signal Processing, In Proceedings of the 2007 IEEE International Symposium on Intelligent Signal Processing, Alcala de Henares, Spain, 2007.
Resumo: The safe and effective application of thermal therapies are limited by the existence of precise non-invasive temperature es-timators. Such estimators would enable a correct power deposition on the region of interest by means of a correct instrumentation control. In multi-layered media, the temperature should be estimated at each layer and especially at the interfaces, where significant temperature changes should occur during therapy. In this work, a non-linear autoregressive structure with exogenous inputs (NARX) was applied to non-invasively estimate temperature in a multi-layered (non-homogeneous) medium, while submitted to physiotherapeutic ultrasound. The NARX structure is composed by a static feed-forward radial basis functions neural network (RBFNN), with external dynamics induced by its inputs. TheNARX structure parameters were optimized by means of a multi- objective genetic algorithm. The best attained models reached a maximum absolute error inferior to 0.5 °C (proposed threshold in hyperthermia/diathermia) at both the interface and inner layer points, at four radiation intensities. These models present also a small computational complexity as desired for real-time applications. To the best of ours knowledge this is the first non-invasive estimation approach in multi-layered media using ultrasound for both heating and estimation.
Peer review: yes
URI: http://hdl.handle.net/10400.1/2255
DOI: http://dx.doi.org/10.1109/WISP.2007.4447544
ISBN: 978-1-4244-0829-0
Aparece nas colecções:FCT2-Artigos (em revistas ou actas indexadas)

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