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São João da Boa Vista, Brazil

Celani de Souza H.J.,Sao Paulo State University | Celani de Souza H.J.,Research and Development | Moyses C.B.,Research and Development | Pontes F.J.,Sao Paulo State University | And 6 more authors.
Molecular and Cellular Probes

Two mutations - Factor V Leiden (1691G > A) and the 20210G > A on the Prothrombin gene - are key risk factors for a frequent and potentially fatal disorder called Venous Thromboembolism. These molecular alterations can be investigated using real-time Polymerase Chain Reaction (PCR) with Fluorescence Resonance Energy Transfer (FRET) probes and distinct DNA pools for both factors. The objective of this paper is to present an application of Taguchi Experimental Design Method to determine the best parameters adjustment of a Molecular Assays Process in order to obtain the best diagnostic result for Venous Thromboembolism investigation. The complete process contains six three-level factors which usually demands 729 experiments to obtain the final result, if using a Full Factorial Array. In this research, a Taguchi L27 Orthogonal Array is chosen to optimize the analysis and reduce the number of experiments to 27 without degrading the final result accuracy. The application of this method can lessen the time and cost necessary to achieve the best operation condition for a required performance. The results is proven in practice and confirmed that the Taguchi method can really offer a good approach for clinical assay efficiency and effectiveness improvement even though the clinical diagnostics can be based on the use of qualitative techniques. © 2011 Elsevier Ltd. Source

Araujo R.S.,Aperam S.A | Rodrigues R.A.,Aperam S.A | De Paula H.,Federal University of Minas Gerais | De Almeida W.P.,CEFET | Da Silveira A.W.F.V.,Federal University of Uberlandia
2012 10th IEEE/IAS International Conference on Industry Applications, INDUSCON 2012

This paper provides a characterization of high-frequency leakage currents in PWM inverters feeding AC motors, contextualized in the analysis of an actual case in which the motor presents premature and recurring failure of its bearings, due to circulation of electric current. From the parameters of an equivalent circuit, in terms of cables, motor and inverter return path, a filter is proposed for mitigation of common-mode currents and related phenomena, characterized by a common-mode transformer. Results from simulations and experimental results show that the proposed transformer represents an advantageous alternative in respect to traditional RC and RLC filters, since, in addition to mitigating common-mode phenomena, the transformer dissipates a negligible amount of power. © 2012 IEEE. Source

Ruas V.,CNRS Jean Le Rond dAlembert Institute | Ruas V.,University of Sao Paulo | Brandao D.,CEFET | Brandao D.,Federal University of Fluminense | Kischinhevsky M.,Federal University of Fluminense
Journal of Computational Physics

Two new Hermite finite elements are shown to be an advantageous alternative to well-known mixed methods in the simulation of diffusion processes in heterogeneous anisotropic media. Both are N-simplex based for N = 2 and N = 3 and provide flux continuity across inter-element boundaries. One of the methods denoted by P2H was introduced by the first author and collaborator for the case of homogeneous and isotropic media. Its extension to the case of heterogeneous and/or anisotropic cases is exploited here, keeping an implementation cost close to the popular Raviart-Thomas mixed finite element of the lowest order, known as RT0. The other method studied in detail in this work is a new Hermite version of the latter element denoted by RT0M. Formal results are given stating that, at least in the case of a constant diffusion, RT0M is significantly more accurate than RT0, although both elements have essentially the same implementation cost. A thorough comparative numerical study of the Hermite methods and RT0 is carried out in the framework of highly heterogeneous media among other cases. It turns out that both are globally superior all the way, and roughly equivalent to each other in most cases. © 2012 Elsevier Inc. Source

Souza A.F.,IEEE EMBS | Coelli F.C.,CEFET
Pan American Health Care Exchanges, PAHCE 2011 - Conference, Workshops, and Exhibits. Cooperation / Linkages: An Independent Forum for Patient Care and Technology Support

The equipment for magnetic resonance imaging (MRI) is the most reliable in the diagnosis area. System failures generate a series of problems: direct financial cost, delay in diagnosis of the patient, increased cost of maintenance contract, among others. This study examined the impact of infrastructure needed for the proper functioning of the MRI equipment availability. After a period of analysis, some suggestions were implemented able to reduce equipment downtime caused by failures in infrastructure. © 2011 IEEE. Source

Petraglia M.R.,Federal University of Rio de Janeiro | Haddad D.B.,CEFET
Digital Signal Processing: A Review Journal

In a context of supervised adaptive filtering, the sparsity of the impulse response to be identified can be employed to accelerate the convergence rate of the algorithm. This idea was first explored by the so-called proportionate NLMS (PNLMS) algorithm, where the adaptation step-sizes are made larger for the coefficients with larger magnitudes. Whereas fast initial adaptation convergence rate is obtained with the PNLMS algorithm for white-noise input, slow convergence is observed for colored input signals. The combination of the PNLMS approach and a subband structure results in an algorithm with better convergence rate for sparse systems and colored input signals. In this paper, the steady-state mean-square error (MSE) and the maximum value of the step-size β that allows convergence of the subband PNLMS-type algorithm are analyzed. Theoretical results are confirmed by simulations. © 2012 Elsevier Inc. All rights reserved. Source

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