44,710 research outputs found
Shape-based defect classification for Non Destructive Testing
The aim of this work is to classify the aerospace structure defects detected
by eddy current non-destructive testing. The proposed method is based on the
assumption that the defect is bound to the reaction of the probe coil impedance
during the test. Impedance plane analysis is used to extract a feature vector
from the shape of the coil impedance in the complex plane, through the use of
some geometric parameters. Shape recognition is tested with three different
machine-learning based classifiers: decision trees, neural networks and Naive
Bayes. The performance of the proposed detection system are measured in terms
of accuracy, sensitivity, specificity, precision and Matthews correlation
coefficient. Several experiments are performed on dataset of eddy current
signal samples for aircraft structures. The obtained results demonstrate the
usefulness of our approach and the competiveness against existing descriptors.Comment: 5 pages, IEEE International Worksho
Electronic marking and identification techniques to discourage document copying
Modern computer networks make it possible to distribute documents quickly and economically by electronic means rather than by conventional paper means. However, the widespread adoption of electronic distribution of copyrighted material is currently impeded by the ease of illicit copying and dissemination. In this paper we propose techniques that discourage illicit distribution by embedding each document with a unique codeword. Our encoding techniques are indiscernible by readers, yet enable us to identify the sanctioned recipient of a document by examination of a recovered document. We propose three coding methods, describe one in detail, and present experimental results showing that our identification techniques are highly reliable, even after documents have been photocopied
Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): Guidelines for medical 3D printing and appropriateness for clinical scenarios
Este número da revista Cadernos de Estudos Sociais estava em organização quando fomos colhidos pela morte do sociólogo Ernesto Laclau. Seu falecimento em 13 de abril de 2014 surpreendeu a todos, e particularmente ao editor Joanildo Burity, que foi seu orientando de doutorado na University of Essex, Inglaterra, e que recentemente o trouxe à Fundação Joaquim Nabuco para uma palestra, permitindo que muitos pudessem dialogar com um dos grandes intelectuais latinoamericanos contemporâneos. Assim, buscamos fazer uma homenagem ao sociólogo argentino publicando uma entrevista inédita concedida durante a sua passagem pelo Recife, em 2013, encerrando essa revista com uma sessão especial sobre a sua trajetória
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