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Power Systems Computation Conference (PSCC)

作者： Brandalik, Robert Henschel, Daniel Wellssow, Wolfram H. Univ Kaiserslautern Chair Energy Syst & Energy Management Kaiserslautern Germany

ISBN: (纸本)9781910963104

The presence of an accurate and efficient system state estimator is a precondition for supervision and closed-loop control of low voltage grids. Such an estimator has to perform in consecutive periods of minutes. Between two periods in most cases, only the measurement values will change, but sometimes also the measurement model. This paper gives suggestions on how to improve the computationally efficiency of state estimation algorithms that have to perform in such an environment. The efficiency improvements are achieved by the application of advanced matrix inversion methods. Further the use of a linear measurement model and the application of the standard augmented matrix approach for solving the state estimation formula is suggested. However, these improvements can also be applied to other measurement models and estimation methods. The efficiency of the improvements is benchmarked against standard methods for different real grid operation cases. In particular, cases when new measurements are added or measurement values get lost are considered. The final result of the paper is an adjustable, robust and efficient algorithm for low voltage state estimation, presented in a way to support manufacturers and operators to implement and maintain it. The paper is a contribution in the field of static state estimation and short-term operation in distribution systems, in particular, low voltage grids.

关键词： Low voltage grids state estimation Taylor approximation augmented matrix approach computationally efficient algorithm

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A computationally efficient State Estimation algorithm for the Supervision of Low Voltage Grids

A computationally efficient State Estimation algorithm for t...

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Power Systems Computation Conference

作者： Robert Brandalik Daniel Henschel Wolfram H. Wellssow Chair for Energy Systems and Energy Management University of Kaiserslautern Kaiserslautern Germany

The presence of an accurate and efficient system state estimator is a precondition for supervision and closed-loop-control of low voltage grids. Such an estimator has to perform in consecutive periods of minutes. Between two periods in most cases, only the measurement values will change, but sometimes also the measurement model. This paper gives suggestions on how to improve the computationally efficiency of state estimation algorithms that have to perform in such an environment. The efficiency improvements are achieved by the application of advanced matrix inversion methods. Further the use of a linear measurement model and the application of the standard augmented matrix approach for solving the state estimation formula is suggested. However, these improvements can also be applied to other measurement models and estimation methods. The efficiency of the improvements is benchmarked against standard methods for different real grid operation cases. In particular, cases when new measurements are added or measurement values get lost are considered. The final result of the paper is an adjustable, robust and efficient algorithm for low voltage state estimation, presented in a way to support manufacturers and operators to implement and maintain it. The paper is a contribution in the field of static state estimation and short-term operation in distribution systems, in particular, low voltage grids.

关键词： Low voltage grids State estimation Taylor approximation Augmented matrix approach computationally efficient algorithm

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A computationally efficient ASIC implementation of space-time block decoding

A computationally efficient ASIC implementation of space-tim...

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Conference on Advanced Signal Processing algorithms, Architectures and Implementations XII

作者： Cavus, E Daneshrad, B Univ Calif Los Angeles Wireless Integrated Syst Res Grp Los Angeles CA 90024 USA

ISBN: (纸本)0819445584

In this paper, we describe a computationally efficient ASIC design that leads to a highly efficient power and area implementation of space-time block decoder compared to a direct implementation of the original algorithm. Our study analyzes alternative methods of evaluating as well as implementing the previously reported maximum likelihood algorithms (Tarokh et al. 1998) for a more favorable hardware design. In our previous study (Cavus et al. 2001), after defining some intermediate variables at the algorithm level, highly computationally efficient decoding approaches, namely sign and double-sign methods, are developed and their effectiveness are illustrated for W, 8x3 and 8x4 systems using BPSK, QPSK, 8-PSK, or 16-QAM modulation. In this work, alternative architectures for the decoder implementation are investigated and an implementation having a low computation approach is proposed. The applied techniques at the higher algorithm and architectural levels lead to a substantial simplification of the hardware architecture and significantly reduced power consumption. The proposed architecture is being fabricated in TSMC 0.18mu process.

关键词： space-time codes block decoding transmit diversity ASIC design computationally efficient algorithm decoder BPSK QPSK QAM

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Nonparametric method of topic identification using granularity concept and graph-based modeling

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NEURAL COMPUTING & APPLICATIONS 2023年第2期35卷 1055-1075页

作者： Ganguli, Isha Sil, Jaya Sengupta, Nandita Indian Inst Engn Sci & Technol Dept Comp Sci & Technol Sibpur Howrah India Univ Coll Bahrain Dept Informat Technol Janabiyah Bahrain

This paper aims to classify the large unstructured documents into different topics without involving huge computational resources and a priori knowledge. The concept of granularity is employed here to extract contextual information from the documents by generating granules of words (GoWs), hierarchically. The proposed granularity-based word grouping (GBWG) algorithm in a computationally efficient way group the words at different layers by using co-occurrence measure between the words of different granules. The GBWG algorithm terminates when no new GoW is generated at any layer of the hierarchical structure. Thus multiple GoWs are obtained, each of which contains contextually related words, representing different topics. However, the GoWs may contain common words and creating ambiguity in topic identification. Louvain graph clustering algorithm has been employed to automatically identify the topics, containing unique words by using mutual information as an association measure between the words (nodes) of each GoW. A test document is classified into a particular topic based on the probability of its unique words belong to different topics. The performance of the proposed method has been compared with other unsupervised, semi-supervised, and supervised topic modeling algorithms. Experimentally, it has been shown that the proposed method is comparable or better than the state-of-the-art topic modeling algorithms which further statistically verified with the Wilcoxon Rank-sum Test.

关键词： Granularity Point-wise mutual information Graph-based modeling Hierarchical structure computationally efficient algorithm

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Expectation-maximisation approach to blind source separation of nonlinear convolutive mixture

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IET SIGNAL PROCESSING 2007年第2期1卷 51-65页

作者： Zhang, J. Woo, W. L. Dlay, S. S. Newcastle Univ Sch Elect Elect & Comp Engn Newcastle Upon Tyne NE1 7RU Tyne & Wear England

A novel learning algorithm for blind source separation of post-nonlinear convolutive mixtures is proposed. The proposed mixture model characterises both convolutive mixture and post-nonlinear distortions of the sources. A novel iterative technique based on a maximum likelihood approach is developed where the expectation-maximisation (EM) algorithm is generalised to estimate the parameters in the proposed model. In the E-step of the proposed framework, sufficient statistics of the posterior distribution of the source signals are estimated while the model parameters are optimised through these statistics in the M-step. The post-nonlinear distortions, however, render these statistics difficult to express in a closed form, and hence, this causes intractability in the M-step. A computationally efficient algorithm is further proposed to facilitate the E-step tractable and the self-updated multilayer perceptron is developed in the M-step to estimate the nonlinearity. The theoretical foundation of the proposed solution has been rigorously developed and discussed in detail. Both simulations and real-time speech signals have been used to verify the success and efficacy of the proposed algorithm. Remarkable improvement has been obtained when compared with the existing algorithm.

关键词： multilayer perceptrons maximum likelihood approach expectation-maximisation algorithm speech signals expectation-maximisation approach computationally efficient algorithm learning (artificial intelligence) posterior distribution nonlinear convolutive mixture Signal processing and detection Neural computing techniques iterative technique self-updated multilayer perceptron nonlinear distortion learning algorithm EM algorithm Signal processing theory post-nonlinear distortions E-step Interpolation and function approximation (numerical analysis) post-nonlinear convolutive mixtures M-step statistics blind source separation source signals Other topics in statistics

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A Novel Noise Variance and SNR Estimator for OFDM-IM Systems over Nakagami-m Fading Channel

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WIRELESS PERSONAL COMMUNICATIONS 2024年第1期138卷 575-602页

作者： Rao, Bandi Narasimha Sundru, Anuradha Natl Inst Technol Dept Elect & Commun Warangal India

Noise power (Variance) and signal-to-noise ratio (SNR) are the key performance evaluation parameters of wireless communication systems. In this article, a novel algorithm is proposed that effectively estimates the noise power and SNR for orthogonal frequency division multiplexing with index modulation (OFDM-IM) systems operating over a time-varying Nakagami-m fading channel. The inactive subcarriers in each group of the OFDM-IM system simplify the analysis and lead to noise power estimation under ideal as well as realistic conditions of the wireless channel. At the receiver side, by using the proposed algorithm the position of inactive subcarriers can be identified effectively, as these positions are dynamic in the OFDM-IM system. Another simplified algorithm is proposed at the transmitter side for effectively transmitting the inactive subcarriers. The noise power on the sub-channel, average noise power, and average SNR are calculated. Differential noise power can also be estimated to track the channel variations effectively. None of the noise power and SNR estimators are available in the literature for the OFDM-IM systems. Hence, the performance of the proposed estimator is compared with the noise power and SNR estimators available for the classical OFDM systems. Moreover, the performance is also tested in terms of normalized mean square error (NMSE) using extensive computer simulations. The proposed estimator achieves significant improvements in spectral efficiency, energy efficiency, and also achieves much lower computational complexity in contrast to the estimators for the classical OFDM systems.

关键词： computationally efficient algorithm Inactive subcarriers Nakagami channel Power saving Spectrally efficient algorithm

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algorithm for nonstationary delay estimation

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ELECTRONICS LETTERS 1998年第8期34卷 722-723页

作者： So, HC City Univ Hong Kong Dept Elect Engn Kowloon Hong Kong

A computationally efficient algorithm for estimating time delay between signals received at two spatially separated sensors is proposed. The delay estimate is adapted directly to maximise the mean product of the first sensor output and the filtered output of the second received signal. The convergence behaviour and variance of the delay estimate are derived. It is shown that the proposed algorithm outperforms the explicit time delay estimator at a low signal-to-noise ratio.

关键词： estimation theory spatially separated sensors fast algorithm convergence behaviour low SNR convergence of numerical methods nonstationary delay estimation Signal processing and detection low signal-to-noise ratio Interpolation and function approximation (numerical analysis) signal processing Information theory approximation theory delays computationally efficient algorithm time delay

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Detection-estimation based approach for impulsive noise removal

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ELECTRONICS LETTERS 1998年第5期34卷 449-450页

作者： Lee, KC Song, HJ Sohn, KH Yonsei Univ Dept Radio Sci & Engn Seoul 120749 South Korea

A new algorithm for effectively removing impulsive noise in digital images is proposed. The computationally efficient algorithm presented first classifies corrupted pixels and then performs median filtering for them only. New efficiency factors are introduced to compare the performance of the noise detection algorithms. Simulation results show that the proposed algorithm performs better than existing methods in terms of both objective and subjective evaluations.

关键词： interference suppression estimation theory detection-estimation based approach noise noise detection algorithms signal detection digital images median filtering Optical information, image and video signal processing Pattern recognition efficiency factors corrupted pixel classification Computer vision and image processing techniques image enhancement computationally efficient algorithm impulsive noise removal

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Low-complexity signal detection for large-scale MIMO systems with second-order Richardson method

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ELECTRONICS LETTERS 2020年第9期56卷 467-469页

作者： Khoso, Imran A. Zhang, Xiaofei Shaikh, Abdul Hayee Nanjing Univ Aeronaut & Astronaut Coll Elect & Informat Engn Nanjing 211100 Peoples R China

Linear minimum mean-square error (MMSE) detection achieves near-optimal performance in large-scale multiple-input multiple-output (LS-MIMO) systems but entails high computational complexity due to large matrix inversion operations. In this Letter, a novel computationally efficient algorithm based on second-order Richardson method is proposed to solve the LS-MIMO detection problem. While no a priori information for the first iteration of the second-order Richardson method is available, the conjugate gradient scheme is exploited that greatly reduces the number of iterations to achieve the desired performance. Moreover, the eigenvalue-based acceleration parameters are proposed to further accelerate the convergence rate. Numerical results demonstrate that the proposed detector outperforms the existing methods and approaches the performance of MMSE with a small number of iterations.

关键词： mean square error methods least mean squares methods signal detection matrix inversion MIMO communication iterative methods computational complexity eigenvalues and eigenfunctions large-scale MIMO systems second-order Richardson method linear minimum mean-square error detection achieves near-optimal performance multiple-input multiple-output systems high computational complexity matrix inversion operations computationally efficient algorithm LS-MIMO detection problem eigenvalue-based acceleration parameters low-complexity signal detection

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algorithm FOR COMPLEX-ZERO LOCATION OF REAL BANDLIMITED SIGNALS

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ELECTRONICS LETTERS 1988年第5期24卷 255-257页

作者： ALJALILI, YO BAYES, T LOCKHART, GB UNIV LEEDS DEPT ELECT & ELECTR ENGNLEEDS LS2 9JTW YORKSHIREENGLAND

A computationally efficient algorithm for locating complex zeros of real bandlimited signals is discussed. The amount of processing is minimal rendering the algorithm suitable for real time applications. The performan... 详细信息

关键词： ZSM combined AM/PM modulation scheme complex-zero location computationally efficient algorithm computer simulation modulation phase modulation poles and zeros real bandlimited signals real time applications signal processing test signals zero synchronous modulation

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