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Reliable two-way communication with the nervous system is one of the biggest challenges in the field of neural engineering. Many problems have prevented us to achieve this goal mostly involving the mechanical, biological and electrical interface between neural tissue and the man-made electrodes. Significant results have been achieved to interface with the brain directly and the current research is...
Modifications to the Body Schema refers to the idea that the brain's mapping can be extended to include an external device. Recent research has shown how Brain-Machine Interfaces (BMIs) can be thought of an extension of this concept. While most BMI work has focused on the cortex in relation to this idea, here we study the striatum to see how the actions of a robotic arm are represented in a deep brain...
A time-frequency analysis based on wavelet transform was carried out to extract error related local field potentials (LFPs) resulting from undesired action perturbations during the control of a robotic effector. During this study, a marmoset monkey controlled the movements of a robotic arm while periodically observing the arm unexpectedly moving to the incorrect target during perturbations. LFPs were...
This paper presents a sub-transmission test circuit, aiming to respond to the reality not covered by IEEE test circuits, at this voltage level. It was obtained from the review of electrical networks into which distributed generation is being inserted in Brazil. The Brazilian territorial and power characteristics complement the traditional European and American experiences, as well as responses to...
This paper proposes a new admittance matrix model to approach the behavior of a fully-differential voltage controlled voltage source at low-frequency. The new model is simpler than that reported in the literature, because it not only can directly be used to fill the admittance matrix without extra variables, including gain and input-output impedances, but also the new stamp has few nonzero elements...
The main purposes of this paper is to introduce a new floating memristor emulator circuit based on positive second generation current conveyors (CCII+s). The proposed circuit is very simple, since four CCII+s, six passive elements along with one four quadrant multiplier are only used to obtain the frequency-dependent pinched hysteresis loop of the memristor in the current versus voltage plane. An...
This paper presents a new adaptive equalizer for short reach applications through low-cost plastic optical fiber. The adaptive equalizer uses the spectrum balancing technique to compensate the limited bandwidth caused by the fiber and the external photodiode. The prototype has been implemented in a standard 0.18-µm CMOS process fed at 1 V. It consumes 38.6 mW at 1.25 Gb/s.
This paper presents the first attempt to quantify the individual performance of the subject and of the computer agent on a closed loop Reinforcement Learning Brain Machine Interface (RLBMI). The distinctive feature of the RLBMI architecture is the co-adaptation of two systems (a BMI decoder in agent and a BMI user in environment). In this work, an agent implemented using Q-learning via kernel temporal...
New reinforcement based paradigms for building adaptive decoders for Brain-Machine Interfaces involve using feedback directly from the brain. In this work, we investigated neuromodulation in the Nucleus Accumbens (reward center) during a multi-target reaching task and investigated how to extract a reinforcing or non-reinforcing signal that could be used to adapt a BMI decoder. One of the challenges...
We focused on the joint exploitation of satellite and ground-based technologies in order to understand the kinematic behavior of landslides and subsidence phenomena relevant to different test sites in Europe. In this context, we efficiently exploited C-band and X-band satellite and ground-based SAR data for the investigation of the temporal and spatial pattern of ground deformations caused by natural...
We present an experimental investigation of the electric field generated by a laser induced plasma (LIP) in air for times t< 100 ns. The laser used was a Nd:YAG, with pulses of 7 ns at FWHM, and irradiance I ≈ 1012 W/cm2. The measurements were made by using a central core of a 50 Ω coaxial cable. Our results show different spatio-temporal structures of the electric field potential depending if...
The operation of bang-bang phase detectors (BBPDs) in clock and data recovery circuits (CDRs) is typically modeled in terms of the phase difference between their inputs; however, this approach is not sufficient to describe their dynamic behavior completely. This paper introduces a more comprehensive model of the operation of BBPDs that takes into account phase as well as frequency differences between...
This paper presents an optical receiver for short reach applications through low-cost plastic optical fiber. The limited bandwidth caused by the fiber and the external photodiode is compensated by a new adaptive equalizer based on the spectrum balancing technique. A clock and data recovery circuit is included that minimizes jitter and metastability using a new multi-level bang-bang architecture. The...
The efficient design of optical communication systems with advanced modulation formats need of an exhaustive mathematical study in order to completely understand the dynamics and design trade-offs involved [1]. The multi-carrier signal's nature of OOFDM signals and the inclusion of the laser chirp into the propagation through a dispersive link makes its rigorous analysis quite challenging, though...
We describe the development of a photoplethysmographic fingertip with miokinetic noise attenuation using a pediatric cuff, followed by a 3-axis accelerometer (Acc) that records the movements that distort the photoplethysmographic pulse wave (PPG). Both PPG and accelerometer signals are used as inputs to an adaptive filter in configuration as Adaptive Noise Canceller (ANC) using the averaged least...
This paper presents the results of a study of Quadrature Amplitude Modulation (QAM) coherent reception bit by bit. The research was conducted using statistical modeling methods; the results are compared with the statistical modeling calculation of analytical expression given in previously published documents. In the last year, the discrete signals became widely employed; and with more perspective...
This paper presents a new modification to the affine projection algorithm for adaptive filtering with the purpose of reducing the floating point operations and thus the computational complexity. The modification is achieved codifying the error in the algorithm. Simulation results show a faster convergence speed than the conventional algorithms and an improve in the minimum level of the mean square...
In this paper, a simple element stamp for floating or grounded voltage-controlled voltage sources is proposed. The novelty is that not only the behavior of single-ended, fully-differential and balanced differential operational amplifiers can directly be introduced in the admittance matrix without extra variables, but also the new stamp has few nonzero elements. As a consequence, a reduced and sparse...
In this paper, the trade-off between accuracy and simulation speed in the generation of muti-scroll chaotic attractors at 1-D is analyzed and improved. In a first step, a macromodel based on bipolar transistors and passive elements is used to model the behavior of Opamps, and later on they are used to approach the behavior of all nonlinear system. Hspice simulations are executed to generate chaotic...
This paper presents a high performance 1.2 V–0.18 μm CMOS quasi-digital temperature sensor with frequency output suitable to be used in battery operated systems. The proposed sensor is based on a multivibrator current-to-frequency converter and works properly over a temperature range of −40 to +120 ºC, with a minimum power consumption of 1.8 μW. It presents a linear response, with a sensitivity of...
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