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Publicações

2010

Genetic Algorithm with Local Search for Community Mining in Complex Networks

Autores
Jin, D; He, DX; Liu, DY; Baquero, C;

Publicação
22ND INTERNATIONAL CONFERENCE ON TOOLS WITH ARTIFICIAL INTELLIGENCE (ICTAI 2010), PROCEEDINGS, VOL 1

Abstract
Detecting communities from complex networks has triggered considerable attention in several application domains. Targeting this problem, a local search based genetic algorithm (GALS) which employs a graph-based representation (LAR) has been proposed in this work. The core of the GALS is a local search based mutation technique. Aiming to overcome the drawbacks of the existing mutation methods, a concept called marginal gene has been proposed, and then an effective and efficient mutation method, combined with a local search strategy which is based on the concept of marginal gene, has also been proposed by analyzing the modularity function. Moreover, in this paper the percolation theory on ER random graphs is employed to further clarify the effectiveness of LAR presentation; A Markov random walk based method is adopted to produce an accurate and diverse initial population; the solution space of GALS will be significantly reduced by using a graph based mechanism. The proposed GALS has been tested on both computer-generated and real-world networks, and compared with some competitive community mining algorithms. Experimental result has shown that GALS is highly effective and efficient for discovering community structure.

2010

Permanent magnet vibration power generator as an embedded mechanism for smart hip prosthesis

Autores
Morais, R; Silva, N; Santos, P; Frias, C; Ferreira, J; Ramos, A; Simoes, J; Baptista, J; Reis, M;

Publicação
EUROSENSORS XXIV CONFERENCE

Abstract
This paper describes an improved micro-power electric generator where energy harvested from human movements is used as an everlasting mechanical energy source to suffice smart hip implant electronics power needs. Its architecture is designed so that the mechanical energy promotes the movement of a combination of magnets and a spring embedded inside a Teflon tube, used to reduce friction. The changing magnetic field induces current in two coils so that the output of the generator is the sum of their signals. The end result is like a double generator in one casing. Produced electrical energy is stored in an energy reservoir handed over to a power management module. Experimental results shows that energy harvested from human walking can be used as an effective power source for hip prosthesis implants. (C) 2010 Published by Elsevier Ltd.

2010

3D cell nuclei fluorescence quantification using sliding band filter

Autores
Quelhas, P; Mendonca, AM; Campilho, A;

Publicação
Proceedings - International Conference on Pattern Recognition

Abstract
Plant development is orchestrated by transcription factors whose expression has become observable in living plants through the use of fluorescence microscopy. However, the exact quantification of expression levels is still not solved and most analysis is only performed through visual inspection. With the objective of automating the quantification of cell nuclei fluorescence we present a new approach to detect cell nuclei in 3D fluorescence confocal microscopy, based on the use of the sliding band convergence filter (SBF). The SBF filter detects cell nuclei and estimate their shape with high accuracy in each 2D image plane. For 3D detection, individual 2D shapes are joined into 3D estimates and then corrected based on the analysis of the fluorescence profile. The final nuclei detection's precision/recall are of 0.779/0.803 respectively, and the average Dice's coefficient of 0.773. © 2010 IEEE.

2010

Manufacturing and testing composite overwrapped pressure vessels with embedded sensors

Autores
Frias, C; Faria, H; Frazao, O; Vieira, P; Marques, AT;

Publicação
MATERIALS & DESIGN

Abstract
In this research programme, methodologies for structural health monitoring (SHM) of composite over-wrapped pressure vessels (COPV) were addressed. So, this work is part of the development of a COPV laboratorial prototype incorporated with non-destructive sensing technologies. The aim is to detect and identify critical aspects that can happen during operation, in order to reduce possible safety problems. Fibre Bragg grating (FBG) optical sensors and polyvinylidene fluoride (PVDF) polymeric piezoelectric were the selected sensing technologies. These sensors were embedded in the liner-composite interface during its manufacturing and monitored the prototype while tested under cyclic internal pressure loading. The measurements collected from the sensors were compiled with the analysis of test data and are presented in this paper. Also, the suitability of the two sensing technologies, issues related to sensor embedding and the monitoring strategy are discussed.

2010

A 1.2V 900nW conductance converter

Autores
Miranda, N; Morais, R;

Publicação
Proceedings of the 17th International Conference - Mixed Design of Integrated Circuits and Systems, MIXDES 2010

Abstract
This article describes a new electrical conductance converter method suitable for very low power applications, where energy constraints prevails over speed and measurement accuracy. Method idea gather voltage time integration and shopper stabilization techniques to process noisy low amplitude signals and to overcome severe limitations of weak inversion channel CMOS circuitry. Main features and tradeoffs are exploited. A 1.2V ASIC implementation on standard 0.35µm CMOS schematics is also presented. Post-layout simulations shows a total power consumption lower than 900nW including current source excitation inherent to the conductance measurement. Such low power consumption allows the measurement of several physical parameters on self-powered wireless networks. © 2010 by Department of Microelectronics & Computer Science, Technical University of Lodz.

2010

Portuguese web accessibility in electronic public procurement platforms

Autores
Goncalves, R; Martins, J; Pereira, J; Mamede, H;

Publicação
Proceedings of the 5th Iberian Conference on Information Systems and Technologies, CISTI 2010

Abstract
The Internet is extremely important for the publishing of information and for the interaction between the society elements. Due to this, it's essential that the web presents itself accessible to all, including those with any kind of disability. An accessible web may help the handicapped citizens interact with the society in a more active way, including the electronic public procurement platforms. This paper presents a study made with a universe of 8 Portuguese certified platforms (by CEGER), using a W3C referenced tool (TotalValidator), and presents some statistical results according to the Portuguese Classification of the Enterprises Activities.

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