3,497 research outputs found
34th Midwest Symposium on Circuits and Systems-Final Program
Organized by the Naval Postgraduate School Monterey California. Cosponsored by the IEEE Circuits and Systems Society.
Symposium Organizing Committee: General Chairman-Sherif Michael, Technical Program-Roberto Cristi, Publications-Michael Soderstrand, Special Sessions- Charles W. Therrien, Publicity: Jeffrey Burl, Finance: Ralph Hippenstiel, and Local Arrangements: Barbara Cristi
Experimental control of natural perturbations in channel flow
A combined approach using system identification and feed-forward control design has been applied to experimental laminar channel flow in an effort to reduce the naturally occurring disturbance level. A simple blowing/suction strategy was capable of reducing the standard deviation of the measured sensor signal by 45 %, which markedly exceeds previously obtained results under comparable conditions. A comparable reduction could be verified over a significant streamwise extent, implying an improvement over previous, more localized disturbance control. The technique is effective, flexible, and robust, and the obtained results encourage further explorations of experimental control of convection-dominated flows
KAPow: A System Identification Approach to Online Per-Module Power Estimation in FPGA Designs
In a modern FPGA system-on-chip design, it is often insufficient to simply assess the total power consumption of the entire circuit by design-time estimation or runtime power rail measurement. Instead, to make better runtime decisions, it is desirable to understand the power consumed by each individual module in the system. In this work, we combine boardlevel power measurements with register-level activity counting to build an online model that produces a breakdown of power consumption within the design. Online model refinement avoids the need for a time-consuming characterisation stage and also allows the model to track long-term changes to operating conditions. Our flow is named KAPow, a (loose) acronym for ‘K’ounting Activity for Power estimation, which we show to be accurate, with per-module power estimates as close to ±5mW of true measurements, and to have low overheads. We also demonstrate an application example in which a permodule power breakdown can be used to determine an efficient mapping of tasks to modules and reduce system-wide power consumption by over 8%
Improved Distributed Estimation Method for Environmental\ud time-variant Physical variables in Static Sensor Networks
In this paper, an improved distributed estimation scheme for static sensor networks is developed. The scheme is developed for environmental time-variant physical variables. The main contribution of this work is that the algorithm in [1]-[3] has been extended, and a filter has been designed with weights, such that the variance of the estimation errors is minimized, thereby improving the filter design considerably\ud
and characterizing the performance limit of the filter, and thereby tracking a time-varying signal. Moreover, certain parameter optimization is alleviated with the application of a particular finite impulse response (FIR) filter. Simulation results are showing the effectiveness of the developed estimation algorithm
Adaptation algorithms for data echo cancellation using nonquadratic cost functions
Adaptation algorithms for data echo cancellation using nonquadratic cost function
Dynamically formed black hole+millisecond pulsar binaries in globular clusters
The discovery of a binary comprising a black hole (BH) and a millisecond
pulsar (MSP) would yield insights into stellar evolution and facilitate
exquisitely sensitive tests of general relativity. Globular clusters (GCs) are
known to harbor large MSP populations and recent studies suggest that GCs may
also retain a substantial population of stellar mass BHs. We modeled the
formation of BH+MSP binaries in GCs through exchange interactions between
binary and single stars. We found that in dense, massive clusters most of the
dynamically formed BH+MSP binaries will have orbital periods of 2 to 10 days,
regardless of the mass of the BH, the number of BHs retained by the cluster,
and the nature of the GC's binary population. The size of the BH+MSP population
is sensitive to several uncertain parameters, including the BH mass function,
the BH retention fraction, and the binary fraction in GCs. Based on our models,
we estimate that there are dynamically formed BH+MSP binaries in
the Milky Way GC system, and place an upper limit on the size of this
population of . Interestingly, we find that BH+MSP binaries will be
rare even if GCs retain large BH populations.Comment: 15 pages, 5 figures, 2 tables, accepted for publication in MNRAS,
updated to match published versio
Experimental control of natural perturbations in channel flow
International audienceA combined approach using system identification and feed-forward control design has been applied to experimental laminar channel flow in an effort to reduce the naturally occurring disturbance level. A simple blowing/suction strategy was capable of reducing the standard deviation of the measured sensor signal by 45 %, which markedly exceeds previously obtained results under comparable conditions. A comparable reduction could be verified over a significant streamwise extent, implying an improvement over previous, more localized disturbance control. The technique is effective, flexible, and robust, and the obtained results encourage further explorations of experimental control of convection-dominated flows
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