In this paper, the variable time-stepping decoupled algorithm proposed by Dahlquist, Liniger, and Nevanlinna (DLN algorithm) is used to discretize the coupled Stokes-Darcy model in time. In theory, we prove the stabil...
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In this paper, the variable time-stepping decoupled algorithm proposed by Dahlquist, Liniger, and Nevanlinna (DLN algorithm) is used to discretize the coupled Stokes-Darcy model in time. In theory, we prove the stability and second-order convergence of DLN algorithm. Further, we combine DLN algorithm with the time adaptive algorithm to improve the computational efficiency. Numerical experiments verify the stability and second-order convergence of the DLN algorithm at any arbitrary sequence of time steps.(c) 2023 IMACS. Published by Elsevier B.V. All rights reserved.
Resource allocation is a non-polynomial complete problem in the cloud data center that selects the proper resources to execute many fine computational granularity tasks. Customer requirements and capacity of applicati...
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Resource allocation is a non-polynomial complete problem in the cloud data center that selects the proper resources to execute many fine computational granularity tasks. Customer requirements and capacity of applications change frequently. To bridge the gap between frequently changing customer requirement and available infrastructure for the services, we propose a dynamic resource allocation strategy using an adaptive multi-objective teaching-learning based optimization (AMO-TLBO) algorithm in Cloud computing. To improve the exploration and exploitation capacities, AMO-TLBO introduces the concept of number of teachers, adaptive teaching factor, tutorial training and self-motivated learning. Moreover, a grid-based approach to adaptively assess the non-dominated solutions maintained in an external archive is used. The objectives of AMO-TLBO include minimizing makespan, cost and maximizing utilization using well-balanced load across virtual machines. The evaluation results show that the proposed algorithm outperforms TLBO, MOPSO and NSGA-II algorithms in terms of different performance metrics.
With the continuous progress of image processing and machine vision technology, the demand for efficient and real-time processing is becoming more and more prominent, especially in the field of high-noise image proces...
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ISBN:
(纸本)9798350377040;9798350377033
With the continuous progress of image processing and machine vision technology, the demand for efficient and real-time processing is becoming more and more prominent, especially in the field of high-noise image processing. In this study, an adaptive Gaussian filtering algorithm is proposed, which is implemented based on FPGA and aims to improve the computational efficiency and real-time performance of the image processing system. Compared with the traditional fixed-weight filter, this algorithm is able to dynamically adjust the filtering parameters according to different noise environments, effectively balancing noise suppression and image detail retention. We coded the algorithm using Verilog hardware description language and verified it on PYNQ-Z2 FPGA platform. The experimental results show that the adaptive algorithm outperforms the fixed-weight filtering method in terms of performance, especially in terms of noise suppression and detail preservation. Meanwhile, the FPGA hardware implements the reduction of filtering delay and optimization of resource consumption, making it well suited for real-time applications. This study demonstrates the promise of FPGA adaptive filtering for applications in medical imaging, remote sensing, and intelligent surveillance, which have stringent requirements for high-performance and high-efficiency processing. This research provides new hardware solutions for real-time, high-quality image processing in constrained environments.
The Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is an integrated algorithm employed in the Enhanced Distributed Channel Access (EDCA) in the IEEE 802.11p protocol. CSMA/CA manages the access of pa...
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ISBN:
(纸本)9781509003044
The Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) is an integrated algorithm employed in the Enhanced Distributed Channel Access (EDCA) in the IEEE 802.11p protocol. CSMA/CA manages the access of packets to the medium and its main role is to avoid collisions among them. An essential process of CSMA/CA is the backoff period in which the packets has to wait for a random number of Time Slots (TS) before attempting to access the medium. The backoff operation is based on a simple deterministic approach that does not consider the status of the medium at the time of transmission. In this paper, we propose an adaptive Backoff algorithm (ABA). ABA is based on a probabilistic approach that takes into account the current situation of the medium. ABA is calculated as a function of the packets probability of collision. We present two algorithms ABA1 and ABA2, the function of the former is directly proportional to the collision probability however the function of the latter is exponentially dependent on the collision probability. We develop a Markov-based analytical model to evaluate ABA1 and ABA2, and study the performance of each system.
We solve the problem of increasing the reliability and efficiency of quality control for semiconductor devices and present the analysis of the conditions of measuring the power spectral density of low-frequency noise ...
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We solve the problem of increasing the reliability and efficiency of quality control for semiconductor devices and present the analysis of the conditions of measuring the power spectral density of low-frequency noise in semiconductor devices with spectra of the form G(f) similar to f(-gamma) (gamma is the parameter of shape of the spectrum) under the conditions of mass quality control. The measurement error of the power spectral density under given conditions of measurements strongly depends on the value of the parameter of form of the spectrum. We propose adaptive algorithms aimed at measuring the parameters of low-frequency noise in the cases of a given ultimate measurement error of power spectral density and a given duration of a single measurement. The proposed algorithms include the preliminary evaluation of the parameter of shape of the spectrum with subsequent measurements of the power spectral density of noise for the optimal bandwidth of the filter. The optimal bandwidth of the filter is established according to the results of preliminary evaluation of the parameter of shape of the spectrum. In both cases, we obtain estimates of the gain in a sense of the mean value over the set (ensemble) of controlled products. We also discussed the possibility of adaptive or cognitive adjustment of the parameters of measuring system in the control process based on the results of evaluation of sample means in the training sample.
Full-duplex wireless communication system transmits and receives signals in a same frequency band and at a same time, which solves the problem of the low using efficiency of limited radio spectrum resource, and double...
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ISBN:
(纸本)9781467371407
Full-duplex wireless communication system transmits and receives signals in a same frequency band and at a same time, which solves the problem of the low using efficiency of limited radio spectrum resource, and doubles the channel capacity. However, it also brings a new problem that the full-duplex node will generate a strong self-interference signal. And to deal with the self-interference signal, using existing negative self-interference cancellation and analog self-interference cancellation technology are not enough, effective digital self-interference cancellation is needed for further cancellation. This paper proposes an optimized adaptive algorithm of digital self-interference cancellation based on improved variable step. By using a iteration threshold, we establish a new nonlinear relationship between the step factor and the error signal, which overcomes the slow change problem when the error signal is getting closed to zero, and accelerates the convergence rate.
This paper proposes an adaptive unscented Kalman filter algorithm(ARUKF)to implement fault estimation for the dynamics of high⁃speed train(HST)with measurement uncertainty and time⁃varying noise with unknown ***,regar...
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This paper proposes an adaptive unscented Kalman filter algorithm(ARUKF)to implement fault estimation for the dynamics of high⁃speed train(HST)with measurement uncertainty and time⁃varying noise with unknown ***,regarding the actuator and sensor fault as the auxiliary variables of the dynamics of HST,an augmented system is established,and the fault estimation problem for dynamics of HST is formulated as the state estimation of the augmented ***,considering the measurement uncertainties,a robust lower bound is proposed to modify the update of the UKF to decrease the influence of measurement uncertainty on the filtering ***,considering the unknown time⁃varying noise of the dynamics of HST,an adaptive UKF algorithm based on moving window is proposed to estimate the time⁃varying noise so that accurate concurrent actuator and sensor fault estimations of dynamics of HST is ***,a five-car model of HST is given to show the effectiveness of this method.
A microwave photonic filter (MPF) with an adaptive algorithm is proposed and theoretically analyzed. The structure combines the finite impulse response (FIR) MPF with the adaptive algorithm. The FIR MPF includes varia...
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A microwave photonic filter (MPF) with an adaptive algorithm is proposed and theoretically analyzed. The structure combines the finite impulse response (FIR) MPF with the adaptive algorithm. The FIR MPF includes variable optical attenuators (VOAs) and variable optical delay lines (VDLs). The least mean square (LMS) algorithm can calculate the weight coefficient of each tap in FIR MPF, which can influence the VOA to realize the adaptive filtering process. This adaptive MPF can extract the desired signal from noise precisely. The noise signal can be well suppressed and the signal-to-noise ratio (SNR) can be developed from 4.15 to 25.5 dB. In addition, this adaptive MPF can be suitable for a wide range of signals.
Smart antennas are widely used for wireless communications due to their ability to increase the coverage and capacity of communication systems. adaptive algorithm is one of the core technologies of smart antenna. Adap...
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ISBN:
(纸本)9781509048403
Smart antennas are widely used for wireless communications due to their ability to increase the coverage and capacity of communication systems. adaptive algorithm is one of the core technologies of smart antenna. adaptive beamforming can receive signal from a certain direction by adjusting the array weight vector to enhance the desired signal and suppress the interference and noise. This paper proposes a new adaptive beamforming algorithm by analyzing and improving an algorithm based on projection of gradient vector. We apply this algorithm to a Uniform Linear Array (ULA) and its improved structure to compare its performance with that of the conventional Least Mean Square (LMS) algorithm. Simulation results show the effectiveness of the new algorithm.
Pulse-to-pulse coherent Doppler sonar has been used to provide accurate velocity information, but the occurrence of "range-velocity" ambiguity seriously limits more general applications. Although multi-frequ...
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ISBN:
(纸本)9781479987375
Pulse-to-pulse coherent Doppler sonar has been used to provide accurate velocity information, but the occurrence of "range-velocity" ambiguity seriously limits more general applications. Although multi-frequency and dual-time-interval methods have been used to enlarge the range of ambiguity velocity, it remains limited. Therefore, a combined method of conventional and coherent Doppler sonar using a fixed range of ambiguity velocity has been proposed to provide accurate and precise velocity without velocity ambiguity. The combined method using a fixed range of ambiguity velocity worked well at high SNR, but at low SNR it was not able to provide the same accuracy as seen at high SNR. In order to provide accurate and precise velocities at a wide range of SNR, an adaptive algorithm of ambiguity velocity is proposed. Based on simulation results, the combined method using the adaptive algorithm can provide accurate and precise velocities at a wide range of SNR.
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