Integrated, low-power, low-noise CMOS neural amplifiers have recently grown in importance as large microelectrode arrays have begun to be practical. With an eye to a future where thousands of signals must be transmitt...
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Integrated, low-power, low-noise CMOS neural amplifiers have recently grown in importance as large microelectrode arrays have begun to be practical. With an eye to a future where thousands of signals must be transmitted over a limited bandwidth link or be processed in situ, we are developing low-power neural amplifiers with integrated pre-filtering and measurements of the spike signal to facilitate spike-sorting and data reduction prior to transmission to a data-acquisition system. We have fabricated a prototype circuit in a commercially-available 1.5 /spl mu/m, 2-metal, 2-poly CMOS process that occupies approximately 91,000 square /spl mu/m. We report circuit characteristics for a 1.5 V power supply, suitable for single cell battery operation. In one specific configuration, the circuit bandpass filters the incoming signal from 22 Hz to 6.7 kHz while providing a gain of 42.5 dB. With an amplifier power consumption of 0.8 /spl mu/W, the rms input-referred noise is 20.6 /spl mu/V.
In this article, we derive conditions for existence of zero-forcing multiuser detectors which achieve perfect reconstruction of the transmitted symbols. Compared to similar works in the literature, the derived conditi...
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In this article, we derive conditions for existence of zero-forcing multiuser detectors which achieve perfect reconstruction of the transmitted symbols. Compared to similar works in the literature, the derived conditions allow a reduction in the length of the equalizer filters, while imposing no constraints on the channel order and on the order of the precoder filters. Since the analysis is carried out in time domain, time varying filters are also considered.
This work focuses the problem of further development of the approach to the fast cipher design, based on data-dependent (DD) permutations (DDP). A new class of the DDP-like operations is described. New DD operations (...
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This work focuses the problem of further development of the approach to the fast cipher design, based on data-dependent (DD) permutations (DDP). A new class of the DDP-like operations is described. New DD operations (DDO) are constructed replacing the switching element in the DDP boxes by different controlled elements (CE) having the same size. Full classification of CE with two non-linear outputs is presented. Two subclasses of nonlinear CE, with the best differential characteristics are recommended for the use in the non-linear DDO-boxes synthesis. The non-linear CE boxes are implemented in FPGA modules using the same hardware resources as switching elements. It is shown that the use of the nonlinear DDO, instead of DDP allows one to reduce the number of rounds. With this technique higher Performance/Cost ratio is achieved, while designing fast hardware suitable ciphers.
This work focuses the problem of increasing the performance of the ciphers based on data-dependent (DD) operations (DDO) for VLSI implementations. New minimum size primitives are proposed to design DDOs. Using advance...
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This work focuses the problem of increasing the performance of the ciphers based on data-dependent (DD) operations (DDO) for VLSI implementations. New minimum size primitives are proposed to design DDOs. Using advanced DDOs instead of DD permutations (DDP) in the DDP-based iterative ciphers Cobra-H64 and Cobra H128 the number of rounds has been significantly reduced yielding enhancement of the "performance per cost" value. To obtain further enhancement of this parameter a new crypto-scheme based on the advanced DDOs is proposed. The FPGA implementation of the proposed crypto-scheme achieves higher throughput value and minimizes the allocated resources than the conventional designs.
Recent years witnessed a growing interest in biped walking robots because of their advantageous use in the human environment. However, their control requires many problems to be solved because of the many degrees of f...
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Recent years witnessed a growing interest in biped walking robots because of their advantageous use in the human environment. However, their control requires many problems to be solved because of the many degrees of freedom and nonlinearity in their dynamics. The so-called open loop walking with offline trajectory generation is one of the control approaches in the literature. There are various difficulties involved in this approach, the most important one being the difficulty in tuning the gait parameters. This paper proposes an online fuzzy adaptation scheme for one of the trajectory parameters in the offline generated walking pattern. A fuzzy identifier system, represented as a three-layer feed-forward neural network is employed to compute the parameter as a function of time in simulations. Fuzzy system parameters are adapted via back-propagation. Virtual torsional springs are attached to the trunk center of the biped. The torque generated by the springs serve as the criterion for the tuning and they help maintaining a stable and a longer walk which is necessary for the online tuning process. 3D simulation and animation techniques are employed for a 12-DOF biped robot to test the proposed adaptive method.
Synapses are a critical element of biologically-realistic, spike-based neural computation, serving the role of communication, computation, and modification. Many different circuit implementations of synapse function e...
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ISBN:
(纸本)0262201526
Synapses are a critical element of biologically-realistic, spike-based neural computation, serving the role of communication, computation, and modification. Many different circuit implementations of synapse function exist with different computational goals in mind. In this paper we describe a new CMOS synapse design that separately controls quiescent leak current, synaptic gain, and time-constant of decay. This circuit implements part of a commonly-used kinetic model of synaptic conductance. We show a theoretical analysis and experimental data for prototypes fabricated in a commercially-available 1.5μm CMOS process.
We provide methods of computing multivalued solutions to the Euler-Poisson system and test them in the context of a klystron amplifier. An Eulerian formulation capable of computing multivalued solutions is derived fro...
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We provide methods of computing multivalued solutions to the Euler-Poisson system and test them in the context of a klystron amplifier. An Eulerian formulation capable of computing multivalued solutions is derived from a kinetic description of the Euler-Poisson system and a moment closure. The system of the moment equations may be closed due to the special structure of the solution in phase space. The Eulerian moment equations are computed for a velocity modulated electron beam, which has been shown by prior Lagrangian theories to break in a finite time and form multivalued solutions. The results of the Eulerian moment equations are compared to direct computation of the kinetic equations and a Lagrangian method also developed in the paper. We use the Lagrangian formulation for the explicit computation of wave breaking time and location for typical velocity modulation boundary conditions.
We studied the ultrafast response in metal-semiconductor-metal ultraviolet photodiodes fabricated on GaN. The best performance of a device with 1-μmn finger width and spacing showed a 3.5-ps response. The pulse width...
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Optical coherence tomography (OCT), confocal, and multiphoton microscopy are used to nondestructively monitor in situ cell distribution and cell-matrix interaction in 3-D engineered tissues composed of chitosan scaffo...
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A novel microwave nondestructive testing technique is presented for breast cancer detection. A method utilizing the reflection coefficient at the aperture of a waveguide sensor radiating into a breast is described res...
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A novel microwave nondestructive testing technique is presented for breast cancer detection. A method utilizing the reflection coefficient at the aperture of a waveguide sensor radiating into a breast is described resulting in theoretical microwave images that clearly indicate the presence of a tumor. These images demonstrate the feasibility of detecting breast tumors using this approach
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