An asymptotic solution is presented for the diffraction by a resistive strip which is useful in the simulation of thin dielectric layers. Up to third-order diffraction terms are derived which include the surface wave ...
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An asymptotic solution is presented for the diffraction by a resistive strip which is useful in the simulation of thin dielectric layers. Up to third-order diffraction terms are derived which include the surface wave field effects in a uniform manner. Extensions to the case of conductive and impedance strips are also given in Appendix C. The derivation of the higher order terms is based on the extended spectral ray method. New first-order diffraction coefficients for the impedance, resistive and conductive half planes are also presented. The last are uniform everywhere, including the surface wave field boundaries
The capacity and cutoff rate of frequency-shift keying (FSK) modulation and noncoherent reception when the signal is subject to Rician fading are calculated. Both hard and soft decisions with maximum likelihood combin...
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The capacity and cutoff rate of frequency-shift keying (FSK) modulation and noncoherent reception when the signal is subject to Rician fading are calculated. Both hard and soft decisions with maximum likelihood combining are considered, as well as soft decisions with square-law combining. Optimal code rates are found that minimize the required signal-to-noise ratio for reliable communication.
Most of the existing methods for calculating de ionized fields of monopolar and bipolar corona have ignored the ionization regions and excluded the transient phenomena of corona discharges. In this paper, bipolar de c...
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Most of the existing methods for calculating de ionized fields of monopolar and bipolar corona have ignored the ionization regions and excluded the transient phenomena of corona discharges. In this paper, bipolar de corona was studied with a two-dimensional particle-in-cell simulation, which allowed us to model time-dependent, nonlinear, microscopic phenomena involved in the corona discharge. The technique followed simulation particles that represented electrons, positive ions, and negative ions, and self-consistently calculated the associated electric field that determined the simulation particle motion. Finite element and charge simulation methods were used to solve Poisson's equation while a finite difference scheme was applied to move simulation particles. Multi-scale techniques (nonuniform triangle mesh and variable time step) were employed to reduce numerical noise and increase simulation efficiency. The particle-in-cell simulation was applied to a cylindrical bipolar corona cage problem. Simulation results included one primitive streamer, multi-electrode induced currents, conductor temperature effects, memory effects, the approach to a stationary state, and transient corona saturation.
New generalized split Levinson and Schur algorithms for the two-dimensional linear least squares prediction problem on a polar raster are derived. The algorithms compute the prediction filter for estimating a random f...
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New generalized split Levinson and Schur algorithms for the two-dimensional linear least squares prediction problem on a polar raster are derived. The algorithms compute the prediction filter for estimating a random field at the edge of a disk, from noisy observations inside the disk. The covariance function of the random field is assumed to have a Toeplitz-plus-Hankel structure for both its radial part and its transverse (angular) part. This assumption is valid for some types of random fields, such as isotropic random fields. The algorithms generalize the split Levinson and Schur algorithms in two ways: 1) to two dimensions;and 2) to Toeplitz-plus-Hankel covariances.
Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of...
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Based on RNG k-ε turbulence model and sliding grid technique, solid-liquid two-phase three-dimensional(3-D) unsteady turbulence of full passage in slurry pump was simulated by means of Fluent software. The effects of unsteady flow characteristics on solid-liquid two-phase flow and pump performance were researched under design condition. The results show that clocking effect has a significant influence on the flow in pump, and the fluctuation of flow velocity and pressure is obvious, particularly near the volute tongue, at the position of small sections of volute and within diffuser. Clocking effect has a more influence on liquid-phase than on solid-phase, and the wake-jet structure of relative velocity of solid-phase is less obvious than liquid-phase near the volute tongue and the impeller passage outlet. The fluctuation of relative velocity of solid-phase flow is 7.6% smaller than liquid-phase flow at the impeller outlet on circular path. Head and radial forces of the impeller are 8.1% and 85.7% of fluctuation, respectively. The results provide a theoretical basis for further research for turbulence, improving efficient, reducing the hydraulic losses and wear. Finally, field tests were carried out to verify the operation and wear of slurry pump.
Given an asymptotically stable matrix, we present a method to generate a set of points in the ''parameter variations space'' whose corresponding perturbed matrices are stable, and we use iteratively th...
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Given an asymptotically stable matrix, we present a method to generate a set of points in the ''parameter variations space'' whose corresponding perturbed matrices are stable, and we use iteratively this result to construct the most extended set of such points. The main thrust of this analysis is on the computational aspects of these constructions.
Surface micromachining has enabled the cofabrication of thin-film micromechanical structures and CMOS or Bipolar/MOS integrated circuits, Using linear, single-axis accelerometers as a motivating example, this paper di...
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Surface micromachining has enabled the cofabrication of thin-film micromechanical structures and CMOS or Bipolar/MOS integrated circuits, Using linear, single-axis accelerometers as a motivating example, this paper discusses the fundamental mechanical as well as the electronic noise floors for representative capacitive position-sensing interface circuits, Operation in vacuum lowers the Brownian noise of a polysilicon accelerometer to below 1 mu g/root Hz. For improved sensor performance, the position of the microstructure should be controlled using electrostatic force-feedback. Both analog and digital closed-loop accelerometers are described and contrasted, with the latter using high-frequency voltage pulses to apply force quanta to the microstructure and achieve a very linear response.
It is critical to design a reliable packet transmission scheme to improve throughput in Energy harvesting Wireless sensor network(EH-WSN) or Battery free Wireless sensor network(BF-WSN). We present the Optimal size an...
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It is critical to design a reliable packet transmission scheme to improve throughput in Energy harvesting Wireless sensor network(EH-WSN) or Battery free Wireless sensor network(BF-WSN). We present the Optimal size and rate(OSR) scheme to improve throughput of communication links in the IEEE 802.15.4 based BF-WSN that harvests radio frequency *** on the defined truncated geometrical distribution,we formulate the optimization problem that maximizes the effective throughput of communication link. The solution of the optimization problem yields the optimal triple,namely the optimal packet size, data rate, and Maximum number of transmission trials(MNTT), which is used in the OSR so that throughput is considerably *** results show the OSR scheme can improve throughput.
A new robust optical design for widening the channel passband of wavelength demultiplexers is presented. Instead of a traditional one-Rowland-circle design, a multi-Rowland-circle structure is proposed to tailor the f...
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A new robust optical design for widening the channel passband of wavelength demultiplexers is presented. Instead of a traditional one-Rowland-circle design, a multi-Rowland-circle structure is proposed to tailor the focused image formed by the grating. The properties of channel passband can he controlled by adjusting the positions of the circles. Nearly perfect flat-channel passband was achieved by our simulation.
Two synchronous multiprocessor architectures based on pipelined optical bus interconnections are presented. The first is a linear pipeline with enhanced control strategies which make optimal use of the available commu...
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Two synchronous multiprocessor architectures based on pipelined optical bus interconnections are presented. The first is a linear pipeline with enhanced control strategies which make optimal use of the available communication bandwidth of the optical bus. The second is a two-dimensional architecture in which processors are placed in a square grid and interconnected to one another through horizontal and vertical pipelined optical buses. These architectures allow any two processors to communicate with each other using one (for the linear case) or two (for the two-dimensional case) pipelined bus cycles. Further, they permit all processors to have simultaneous access to the buses using slots within a pipelined cycle. We show that the architectures have simple control structures and that well-known processor interconnections, e.g., the complete binary trees and the hypercube networks, can be efficiently embedded in them. These architectures have an effectively higher bandwidth than conventional bus configurations and appear to be good candidates for a new generation of hybrid optical-electronic parallel computers.
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