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Zapata J.,Tecnologia de Computadoras y Proyectos | Zapata J.,Technical University of Cartagena | Vilar R.,Technical University of Cartagena | Ruiz R.,Tecnologia de Computadoras y Proyectos | Ruiz R.,Technical University of Cartagena
NDT and E International | Year: 2010

In this paper, we describe an adaptive-network-based fuzzy inference system to recognise welding defects in radiographic images. In a first stage, image processing techniques, including noise reduction, contrast enhancement, thresholding and labelling, were implemented to help in the recognition of weld regions and the detection of weld defects. In a second stage, a set of 12 geometrical features which characterise the defect shape and orientation was proposed and extracted between defect candidates. In a third stage, an adaptive-network-based fuzzy inference system (ANFIS) for weld defect classification was used. With the aim of obtaining the best performance to automate the process of the classification of defects, of all possible combinations without repetition of the 12 features chosen, four were used as input for the ANFIS. The results were compared with the aim to know the features that allow the best classification. The correlation coefficients were determined obtaining a minimum value of 0.84. The accuracy or the proportion of the total number of predictions that were correct was determined obtaining a value of 82.6%. © 2009 Elsevier Ltd. All rights reserved. Source


Fernandez-Luque F.,Tecnologia de Computadoras y Proyectos | Zapata J.,Tecnologia de Computadoras y Proyectos | Ruiz R.,Tecnologia de Computadoras y Proyectos
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Ambient Assisted Living (AAL) systems demand is raising. The use of bed seat occupancy sensors is imperative for this kind of ubiquitous monitoring systems. Pressure mats are a first way to solve this feature, but several environmental dependencies make them weak to be an efficient and reliable solution for large volume deployments. Solutions based on force-to-resistor transducer seems to imply a too high power consumption to be integrated on wireless sensor nodes. A force-capacitive transducer based sensor has been proposed, implemented and tested in this paper. This sensor, based on Electro-Mechanical Films (EMFi) is able to detect force variations in a quasi-passive way. This detection is used to trigger an active mechanism to measure the weight by means of the transducer capacity. A low-power wireless sensor node prototype including this new sensor has been assembled and tested with a wide range of weights. The occupancy detection was successful and the power consumption of the node was increased at less that a 15%. © 2011 Springer-Verlag Berlin Heidelberg. Source


Fernandez-Luque F.J.,Tecnologia de Computadoras y Proyectos | Fernandez-Luque F.J.,Technical University of Cartagena | Perez D.,Ambient Intelligence and Interaction | Perez D.,Technical University of Cartagena | And 9 more authors.
Ad Hoc Networks | Year: 2013

DIA (Dispositivo Inteligente de Alarma, in Spanish) is an AAL (Ambient Assisted Living) system that allows to infer a potential dangerous action of an elderly person living alone at home. This inference is obtained by a specific sensorisation with sensor nodes (portables and fixes) and a reasoning layer embedded in a PC that learns of the users behaviour patterns and advices when actual one differs significantly of the normal patterns. In AAL systems, energy is a limited resource therefore sensor devices need to be properly managed to conserve energy. In this paper, we introduce the design and implementation of innovative and specific mechanisms at the sensory layer middleware which is capable of, first to discriminate spurious motion detections assuming that these signals do not resemble the patterns of real motion detections and, second to reduce the dynamics of messages by a sensor signal processing in order to compress the whole information in one single event. The middleware achieves power saving by modifying the raw information from sensors and adapting it to the predefined semantic of the reasoning layer. It manages the important task of data processing from sensors (raw information), and transfers the pre-processed information into the top layer of reasoning in a more energy efficient way. We also address the trade-off between reducing power consumption and reducing delay for incoming data. We present results from experiments using our implementation of these mechanisms at the middleware that comprises from node firmware to the PC driver. The number of messages of the proposed method with respect to the raw data is reduced by approximately 98.5%. The resources used in the PIR signal processing is reduced by approximately 85%. The resulting delay introduced is small (10-19 s) but system dynamics is slow enough to avoid contextualisation errors or reduction of system performance. We consider these results as very satisfactory. © 2012 Elsevier B.V. All rights reserved. Source


Fernandez-Luque F.J.,Tecnologia de Computadoras y Proyectos | Martinez F.,Tecnologia de Computadoras y Proyectos | Domenech G.,Tecnologia de Computadoras y Proyectos | Zapata J.,Tecnologia de Computadoras y Proyectos | Ruiz R.,Tecnologia de Computadoras y Proyectos
Sensors and Actuators, A: Physical | Year: 2013

The use of bed/couch occupancy sensors is imperative for certain ubiquitous computing systems such as ambient assisted living (AAL). DIA (Dispositivo Inteligente de Alarma, in Spanish) is an AAL system that allows to infer a potential dangerous action of a dependant person living alone at home. This inference is obtained by a specific sensitization with sensor nodes and a reasoning layer embedded in a personal computer. In this kind of systems, energy is a limited resource therefore sensor devices need to be properly managed to conserve energy. A first approach to solve the bed/couch occupancy detection problem is found in pressure mats, but several environmental dependencies make them weak to be an efficient and reliable solution for large volume deployments. Solutions based on force-to-resistor transducer imply a too high power consumption to be integrated on wireless sensor nodes. In our previous paper, an occupancy sensor based on force-capacitive transducer has been proposed, implemented and tested. This sensor is based on electro-mechanical film (EMFi) transducer which is able to detect force variations in a quasi-passive way and, besides, is a capacitor with variable capacitance depending on the static force exerted on its surface. This detection of force change is used to trigger an active mechanism to measure the weight by means of the transducer capacitance. In this paper, we present a new low-power circuit to measure weight, by means of the capacitance of the EMFi transducer, which enhances accuracy and power consumption, simplifies the signal sampling procedure and can be implemented as a standalone device. A low-power wireless sensor node prototype including this new design has been assembled and tested with a wide range of weights. The occupancy detection was successful and the power consumption of the occupancy sensor accounts for only 2%, which is acceptable for implementation. © 2012 Elsevier B.V. All rights reserved. Source

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