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Noskoski O.A.,Southern Federal Institute of Education and Technology | Bermudez J.C.M.,Federal University of Santa Catarina | De Almeida S.J.M.,Catholic University of Pelotas
IEEE Transactions on Signal Processing | Year: 2013

Identification of systems with sparse impulse response encounters large applicability. Numerous techniques have been proposed to identify such systems efficiently. One strategy that leads to specially good results is to detect the active (nonzero) response samples and update only the corresponding adaptive coefficients. Wavelet-based approaches have been shown to be specially effective to this end. This paper proposes a new region-based wavelet-packet (RBWP) algorithm for efficient identification of systems with sparse impulse responses with arbitrary frequency spectra and with any delay of the effective response. The discrete wavelet packet transform (DWPT) is adaptively tailored to the energy distribution of the unknown system's response spectrum. The new algorithm leads to a reduced number of active weights and to a reduced computational complexity, when compared with competing wavelet-based algorithms. Monte Carlo simulation results show good performances regarding convergence speed and robustness to design parameter choice. © 1991-2012 IEEE. Source


Cassana F.F.,Southern Federal Institute of Education and Technology | Eller C.B.,University of Campinas | Oliveira R.S.,University of Campinas | Dillenburg L.R.,Federal University of Rio Grande do Sul
Plant and Soil | Year: 2016

Background and aims: Foliar water uptake has been reported for different species, including conifers living in drought-prone environments. We conducted three experiments to determine whether leaves might absorb mist water and how this affects the water relations of well-watered and water-stressed young plants of Araucaria angustifolia. Methods: Three independent experiments were conducted using well-watered and water-stressed plants: immersion of shoot in water for the quantification of water uptake, the short-term exposure of plants to deuterium-enriched artificial mist, followed by the evaluation of plant water status and δ2H of xylem and soil water, and the use of the heat ratio method to measure the sap flow in saplings submitted to artificial mist. Results: Foliar water uptake was demonstrated in both groups of plants, but only water-stressed plants showed a significant improvement of shoot water status. Isotope analyses indicated release of mist water in water-stressed plants rhizosphere’s, and measurements of sap flow pointed to flow reversals in saplings exposed to mist, after a soil drought period. Conclusions: The results confirm the capacity of A. angustifolia for absorbing water deposited in its leaves and demonstrate that leaf-absorbed water can be transported through the xylem to the soil close to the roots and improve plant water status. © 2015, Springer International Publishing Switzerland. Source


Machado M.B.,Southern Federal Institute of Education and Technology | Schneider M.C.,Federal University of Santa Catarina | Galup-Montoro C.,Federal University of Santa Catarina
Analog Integrated Circuits and Signal Processing | Year: 2014

This paper presents two fully integrated inductive ring oscillators that operate with supply voltages below 2kT/q for energy harvesting applications. Expressions for the oscillation frequency as well as the minimum transistor gain and supply voltage required for the starting up of oscillations are derived for each topology. The experimental results for two cross-coupled oscillators, with topologies comprised of a single-inductor and two-inductors per stage, are presented. The two oscillators operate with supply voltages as low as VDD = 46 mV at 11.5 µW DC power and VDD = 31 mV at 15 µW DC power, respectively, thus confirming the extremely low voltage operation of the prototypes integrated in a 130 nm technology. © 2014, Springer Science+Business Media New York. Source


Martins A.,Southern Federal Institute of Education and Technology | Fonseca M.,Federal University of Pelotas | Fonseca M.,Catholic University of Pelotas | Costa E.,Catholic University of Pelotas
Proceedings of the IEEE International Conference on Electronics, Circuits, and Systems | Year: 2016

In this paper, we seek the optimal combination of dedicated radix-2m multiplication blocks, and adder trees schemes for the realization of optimized radix-2m array multipliers. The operands of the multipliers are generated by 2's complement radix-4, radix-16, radix-256, and radix-65536 dedicated multiplication blocks. The operands are added using different adder trees schemes such as Wallace, RBA, and compressors. The number of operands defines the amount of adders blocks used in the addition tree of the array multiplier. The logic synthesis was realized using Cadence Encounter RTL Compiler tool with Nangate 45nm Open Cell library. Area, delay and power consumption results are presented for the synthesized proposed multipliers. As will be presented, the combination of radix-4 or radix-16 dedicated multiplication block and multi-operand adder tree schemes yields the best power - performance results in the radix-2" array multipliers. © 2015 IEEE. Source


De Oliveira Cacho R.,Federal University of Rio Grande do Norte | Cacho E.W.A.,Federal University of Rio Grande do Norte | Ortolan R.L.,Southern Federal Institute of Education and Technology | Cliquet A.,University of Campinas | Borges G.,University of Campinas
Medicine (United States) | Year: 2015

The objective of this study was to evaluate the long-term effects of the task-specific training with trunk restraint compared with the free one in poststroke reaching movements. The design was randomized trial. The setting was University of Campinas (Unicamp). Twenty hemiparetic chronic stroke patients were selected and randomized into 2 training groups: trunk restraint group (TRG) (reaching training with trunk restraint) and trunk free group (TFG) (unrestraint reaching). Twenty sessions with 45 minutes of training were accomplished. The patients were evaluated in pretreatment (PRE), posttreatment (POST) and 3 months after the completed training (RET) (follow-up). Main outcome measures were modified Ashworth scale, Barthel index, Fugl-Meyer scale, and kinematic analysis (movement trajectory, velocity, angles). A significant improvement, which maintained in the RET test, was found in the motor (P<0.001) and functional (P=0.001) clinical assessments for both groups. For trunk displacement, only TFG obtained a reduction statistical significance from PRE to the POST test (P=0.002), supporting this result in the RET test. Despite both groups presenting a significant increase in the shoulder horizontal adduction (P=0.003), only TRG showed a significant improvement in the shoulder (P=0.001 - PRE to POST and RET) and elbow (P=0.038 - PRE to RET) flexion extension, and in the velocity rate (P=0.03 - PRE to RET). The trunk restraint therapy showed to be a long-term effective treatment in the enhancement of shoulder and elbow active joint range and velocity rate but not in the maintenance of trunk retention. © 2015 Wolters Kluwer Health, Inc. Source

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