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Publications

Publications by Ireneu Dias

2008

Intelligent optical sensors using artificial neural network approach

Authors
Dias, I; Oliveira, R; Frazao, O;

Publication
INNOVATION IN MANUFACTURING NETWORKS

Abstract
This work present and demonstrated an applications of artificial neural network approach in optical sensing. The conventional matrix method used in simultaneous measurement of strain and temperature with optical Bragg gratings is compared with artificial neural network approach. The alternative method is proposed for reduced the error.

2006

The signal characteristics of the spectral response of Bragg grating sensor embedded in composite laminated after the cure process

Authors
Ramos, CA; Frazao, O; Dias, I; Marques, AT;

Publication
ADVANCED MATERIALS FORUM III, PTS 1 AND 2

Abstract
The objective of this work was to study, understand and evaluate the effect of different geometric configurations of carbon plies, in the reflected wavelength spectrum of Bragg grating structure together with the effect of the recoating process of the sensor. The different possibilities depend upon the orientation and location of the optical fibre relative to the composite reinforcement orientation and the presence/absence of recoating. The material stacking sequence and the cure conditions were are also studied and the influence of the different possibilities was considered. The optical spectrum response obtained by the interaction of the optical fibre with the host material is shown.

2009

A SIMPLE SMART COMPOSITE USING FIBER BRAGG GRATING SENSORS FOR STRAIN AND TEMPERATURE DISCRIMINATION

Authors
Frazao, O; Oliveira, R; Dias, I;

Publication
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS

Abstract
A smart laminated composite with a simple geometry was produced with embedded fiber Bragg grating sensors. The smart structure is composed of two Bragg gratings located in regions of different thicknesses of the laminated composite. Although one of the Bragg gratings is embedded between two layers, the other is embedded in jour layers. When the strain is applied to the smart composite, different response is obtained. Because of this characteristic it is possible to discriminate strain and temperature using a traditional matrix method. To reduce the inherent error, an artificial neural network approach is proposed that will improve the strain and temperature measurement discrimination when using this new configuration. These instrumented carbon fiber laminates can be used for monitoring of reinforcement and protection of structures. (C) 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 235-239, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23990

2010

Dynamic Interrogation of Long Period Gratings with Modulated Fibre Bragg Gratings

Authors
Carvalho, JP; Coelho, L; Correia, L; Frazao, O; Jorge, PAS; Baptista, JM; Dias, I; Santos, JL; Weyl, J; Pontes, MJ; Martinez, MA; Barbero, AP; Ribeiro, RM; Abelem, AJG; Giraldi, MTR;

Publication
FOURTH EUROPEAN WORKSHOP ON OPTICAL FIBRE SENSORS

Abstract
It is reported a LPG dynamic interrogation technique based on the modulation of fibre Bragg gratings located in the readout unit that permits to attenuate the effect of the 1/f noise of the electronics in the resolution of the LPG-based sensing head. The concept is tested to detect variations of the external refractive index and a resolution of 2.0x10 (4) NIR was achieved without system optimization. Additionally, the effect in the sensor resolution when introducing Erbium and Raman optical amplification is experimentally investigated.

2009

Optical Fibre Sensing Networks

Authors
Santos, JL; Frazao, O; Baptista, JM; Jorge, PAS; Dias, I; Araujo, FM; Ferreira, LA;

Publication
2009 SBMO/IEEE MTT-S INTERNATIONAL MICROWAVE AND OPTOELECTRONICS CONFERENCE (IMOC 2009)

Abstract
This presentation gives a review of the main concepts behind fibre optic sensing networks. Some important application areas are mentioned, such as the monitoring of oil fields, of large Civil Engineering structures, as well as of natural environments. Then, it will be addressed the potential relevance of this technology in domains of increasingly social importance, such as Health and Elderly Care, particularly in the development of Personal Health Systems.

2012

Long-Period Gratings Dynamic Interrogation With Modulated Fiber Bragg Gratings and Optical Amplification

Authors
Carvalho, JP; Coelho, L; Pontes, MJ; Barbero, AP; Martinez, MA; Ribeiro, RM; Weyl, J; Baptista, JM; Giraldi, MTR; Dias, I; Santos, JL; Frazao, O;

Publication
IEEE SENSORS JOURNAL

Abstract
It is reported a long-period grating (LPG) dynamic interrogation technique based on the modulation of fiber Bragg gratings located in the readout unit of the system. It permits to attenuate the effect of the 1/f noise of the electronics in the resolution of the LPG-based sensing head. The concept is tested to detect variations of the external refractive index and a resolution of 2.0 x 10(-4) NIR was achieved without system optimization. Additionally, the effect in the sensor resolution when introducing Erbium and Raman optical amplification is experimentally investigated.

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