tailieunhanh - Báo cáo sinh học: " Review Article Fluctuation Analyses for Pattern Classification in Nondestructive Materials Inspection"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Review Article Fluctuation Analyses for Pattern Classification in Nondestructive Materials Inspection | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID 262869 12 pages doi 2010 262869 Review Article Fluctuation Analyses for Pattern Classification in Nondestructive Materials Inspection A. P. Vieira 1 E. P. de Moura 2 and L. L. Goncalves2 1 Instituto de Fisica Universidade de Sao Paulo 05508-090 Sao Paulo SP Brazil 2 Departamento de Engenharia MetalUrgica e de Materiais Universidade Federal do Ceará 60455-760 Fortaleza CE Brazil Correspondence should be addressed to L. L. Goncalves lindberg@ Received 30 December 2009 Accepted 25 June 2010 Academic Editor Joao Marcos A. Rebello Copyright 2010 A. P. Vieira et al. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. We review recent work on the application of fluctuation analyses of time series for pattern classification in nondestructive materials inspection. These analyses are based on the evaluation of time-series fluctuations across time intervals of increasing size and were originally introduced in the study of fractals. A number of examples indicate that this approach yields relevant features allowing the successful classification of patterns such as i microstructure signatures in cast irons as probed by backscattered ultrasonic signals ii welding defects in metals as probed by TOFD ultrasonic signals iii gear faults based on vibration signals iv weld-transfer modes as probed by voltage and current time series v microstructural composition in stainless steel as probed by magnetic Barkhausen noise and magnetic flux signals. 1. Introduction Many nondestructive materials-inspection tools provide information about material structure in the form of time series. This is true for ultrasonic probes acoustic emission magnetic Barkhausen noise among others. Ideally signatures of material .