The stability analysis of a class of nonlinear PD-plus-feedforward controllers is presented for the tracking control of rigid robot manipulators. The controller structure is composed of a nonlinear gain PD feedback co...
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The stability analysis of a class of nonlinear PD-plus-feedforward controllers is presented for the tracking control of rigid robot manipulators. The controller structure is composed of a nonlinear gain PD feedback controller and a manipulator dynamics feedforward term. The class of representations used for the nonlinear gain PD feedback controller is extended and global exponential stability is proved. Simulation results are included to illustrate the performance of this class of nonlinear controllers.
A multi-objective design methodology that uses an evolutionary algorithm optimization process is presented and is applied to the simultaneous optimal design of a robotic manipulator/controller for performing point-to-...
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A multi-objective design methodology that uses an evolutionary algorithm optimization process is presented and is applied to the simultaneous optimal design of a robotic manipulator/controller for performing point-to-point motion tasks. Dynamic performance measures, for the closed-loop system, are optimized by considering a nonlinear PD controller and quintic polynomial trajectories for point-to-point motions. Results of the simultaneous optimal design of a planar manipulator, a non-linear controller, and some sample trajectories are presented to illustrate the efficacy of this methodology.
This paper introduces the concept of frequency-translating, bandpass delta-sigma modulator in continuous-time. The system level design and simulation results of the delta-sigma modulator are presented. The DAC jitter ...
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This paper introduces the concept of frequency-translating, bandpass delta-sigma modulator in continuous-time. The system level design and simulation results of the delta-sigma modulator are presented. The DAC jitter performance of the continuous-time, frequency translating bandpass delta-sigma modulator is presented. The DAC jitter performance of the frequency translating modulator and conventional lowpass delta-sigma modulator are compared.
To determine the properties of a physical medium based upon a collection of measurements using microwave is the objective of many applied sciences and engineering problems. These electromagnetic inverse scattering pro...
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To determine the properties of a physical medium based upon a collection of measurements using microwave is the objective of many applied sciences and engineering problems. These electromagnetic inverse scattering problems are ill-posed, computationally expensive and have to fuse multi-sensor data from sparsely sampled, noisy observations. In this work, we solve the extended Born approximation (EBA) of permittivity perturbation in wavelet domain for microwave frequency bands and employ the multiscale statistical method to reconstruct the structure of the unknown. The computational complexity is reduced since the matrices defining the EBA are sparsified in wavelet domain.
Virtually all implementations of simulated annealing are simplified by assuming discrete unknowns, however continuous-parameter annealing has many potential applications to image processing. Widely scattered problems ...
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Virtually all implementations of simulated annealing are simplified by assuming discrete unknowns, however continuous-parameter annealing has many potential applications to image processing. Widely scattered problems such as formant tracking, boundary estimation and phase- unwrapping can all be approached as the annealed minimizations of continuous B-spline parameters. The benefits of simulated annealing are well known, including an insensitivity to initial conditions and the ability to solve problems with many local minima. Discrete variable annealing has seen broad application, however continuous-variable annealing is limited by the computational challenge of Gibbs sampling. In this paper we develop efficient approaches to sampling, illustrated in the context of contour tracking in noisy images.
A strategy for the implementation of energy-efficient architecture blocks is proposed. In enables mapping of algorithms to architectures at maximal efficiency based on automized optimization of device dimensions of el...
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A strategy for the implementation of energy-efficient architecture blocks is proposed. In enables mapping of algorithms to architectures at maximal efficiency based on automized optimization of device dimensions of elementary basic cells. As an example, the design of a high-throughput low-power FIR-filter is described. The effectiveness of the proposed strategy is confirmed by comparison with state-of-the-art filter macros.
This paper presents a new methodology for layout-aware synthesis of analog systems. The methodology combines block parameter exploration, block placement and global interconnect routing while maintaining an accurate p...
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ISBN:
(纸本)0769519040
This paper presents a new methodology for layout-aware synthesis of analog systems. The methodology combines block parameter exploration, block placement and global interconnect routing while maintaining an accurate perspective on the layout parasitics. An original system representation (called Layout Constraint Graphs - LCG) was developed for synthesis. The paper discusses how block parameter exploration, placement and global routing are expressed in terms of the LCG graph. AC and transient performances of each explored solution are obtained using SPICE simulations. Experiments show the generality of the synthesis methodology by providing results for several applications including filters and converters.
In the recent years a lot of research effort is being spent in the areas of nanotechnology, quantum computation, and biologically inspired computing. As we are faced with various challenges regarding their implementab...
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In the recent years a lot of research effort is being spent in the areas of nanotechnology, quantum computation, and biologically inspired computing. As we are faced with various challenges regarding their implementability, architectural visions, and design automation, not much has been done in the field of high level design and validation in looking further into the future, and ponder about the state of the art in design validation and test in such miniscule technology era. Very few reported research work have surfaced on the design and validation challenges for these technologies. However, this certainly is a matter of concern because the technology of the small will be ridden with random faults and hence architectural design strategies need to change to take into account these stochastic models of failures to build robust designs. Validation of such designs also have to capture the stochastic behavioral models of the technology, and hence traditional validation and testing techniques will not work directly. Are we getting ready with our theory; technology and tools to address these challenges? This futuristic panel asks technology and computer aided design experts, as well as finding agency program managers questions about the technological barriers to be surpassed, as well as how the funding agencies such as NSF are ramping up for this technological future.
Many similarities can be found between military training and computer game simulators. A review of definitions and classifications of military training simulators suggests that an adoption of DoD terminology also woul...
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ISBN:
(纸本)1565552687
Many similarities can be found between military training and computer game simulators. A review of definitions and classifications of military training simulators suggests that an adoption of DoD terminology also would suit game industry requirements. Similarities between applications are exemplified. Adhering to a common standard could possibly impose a challenge to both sectors because of (a) the rapid development of new concepts in the games sector, (b) the crossover between genres, and (c) the increasingly unclear distinction between "live" applications and simulations. The conclusion proposes further investigation into possible category dimensions that may emanate from research.
Simultaneous multithreading (SMT) attempts to attain higher processor utilization by allowing instructions from multiple independent threads to coexist in a processor and compete for shared resources. Previous studies...
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Simultaneous multithreading (SMT) attempts to attain higher processor utilization by allowing instructions from multiple independent threads to coexist in a processor and compete for shared resources. Previous studies have shown, however, that its throughput may be limited by the number of threads. A reason is that a fixed thread scheduling policy cannot be optimal for the varying mixes of threads it may face in an SMT processor. Our adaptive dynamic thread scheduling (ADTS) was previously proposed to achieve higher utilization by allowing a detector thread to make use of wasted pipeline slots with nominal hardware and software costs. The detector thread adaptively switches between various fetch policies. Our previous study showed that a single fixed thread scheduling policy presents much room (some 30%) for improvement compared to an oracle-scheduled case. In this paper, we take a closer look at ADTS. We implemented the functional model of the ADTS and its software architecture to evaluate various heuristics for determining a better fetch policy for a next scheduling quantum. We report that performance could be improved by as much as 25%.
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