In this paper, a beamforming based enhanced method for noise/echo cancellation in audio devices such as hearing aids is presented. A modified two-element beamformer scheme is proposed as a possible solution for better...
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We have developed a method of catalyst preparation for carbon nanotube (CNT) growth that uses solid-state diffusion to precipitate Co particles in a Cu matrix and control the size and size distribution of catalyst par...
We have developed a method of catalyst preparation for carbon nanotube (CNT) growth that uses solid-state diffusion to precipitate Co particles in a Cu matrix and control the size and size distribution of catalyst particles. Copper is an excellent electrical and thermal conductor, and has a small or negligible solubility for Co. Cu–Co alloys of approximately 5 atm% Co were formed in bulk by splat quenching the liquid alloy and on Si substrates by e-beam evaporation of the alloy, sputtering of the alloy, and sputter deposition of thin films of pure Cu and Co. The Co easily precipitates from dilute solutions of Cu–Co with heat treatment. These alloys and films were used to generate uniform distributions of Co precipitates, and CNTs were successfully grown by plasma enhanced chemical vapor deposition (PE-CVD) and thermal CVD on the materials. These alloys can be patterned by photolithography and sputtering in order to grow CNTs in defined locations. Therefore, the technique is amenable to very large scale silicon integration for field emission applications. The results of this work and data from field emission studies are presented herein.
Electric, water, gas and transportation utilities face severe challenges associated with security, quality, availability, reliability and profitability issues. They must solve interrelated system problems with respect...
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Electric, water, gas and transportation utilities face severe challenges associated with security, quality, availability, reliability and profitability issues. They must solve interrelated system problems with respect to generation of electricity, transportation of fuel, and potable as well as waste water. In the future, engineers and managers of utilities must be well versed in the different disciplines of engineering including electrical civil, mechanical and information technology. The University of Colorado at Boulder addresses this educational opportunity by proposing a novel Integrated Utilities Management program for M.S. candidates who have a solid B.S. background or equivalent in a related discipline. The M.S. program will consist of four interdisciplinary paths dealing with business management and legal topics as they relate to federal and state regulatory issues, as well as agency and people-related leadership issues. The electric utilities option of this program will be centered on three core courses related to electric power generation/transmission and distribution, security and availability, quality and reliability, economics and environmental policy, and utility finance;two elective courses from a group of courses that address nuclear power, waste water, solid waste, telecommunications, renewable energies, data communication, fuels and case studies;and one capstone course consisting of either operations research or the investigation and resolution of a pending utility project such as the right-of-way of transmission lines, specification of new power plants, retrofitting of power plants or their impact on the environment. It is expected that candidates for this MS program will come from universities, from utilities, and from private and public agencies. The MS program can be completed by full- or part time students within one or two years of intensive study, respectively. Courses will be taught both on campus and nationwide via the Center for Advanced
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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We present the design, implementation and evaluation of a location detection system built over a Radio Frequency network based on the IEEE 802.11 standard. Our system employs beacons to broadcast identifying packets f...
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A programmable arbitrary waveform generator for creation of experimental defibrillation shocks is described. The system is capable of delivering shocks for internal defibrillation via 10 channels at 1000 Volts and 30 ...
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A programmable arbitrary waveform generator for creation of experimental defibrillation shocks is described. The system is capable of delivering shocks for internal defibrillation via 10 channels at 1000 Volts and 30 Amps. A microcontroller driven system that can receive waveform commands from a laptop was designed to be able to deliver shocks to any combination of electrodes. Waveforms are controllable down to 100 microsecond intervals and each channel is capable of serving as anode or cathode. This system can be used to verify predictions for defibrillation waveform efficacy as predicted by modeling efforts or to test new experimental waveforms tuned to parameters from an individual subject.
Expressions for the electromagnetic power extinguished by a scatterer in a half-space are derived via the generalized optical theorem. The power is seen to be related to the structure of the scattering object. Applica...
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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 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.
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