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Anomaly Detection for the European XFEL using a Nonlinear Parity Space Method

IFAC-PapersOnLine 2018年第24期51卷 1379-1386页

作者： Nawaz, A. Pfeiffer, S. Lichtenberg, G. Rostalski, P. Deutsches Elektronen Synchrotron Hamburg Germany University of Applied Science Hamburg Germany University of Luebeck Germany

The European XFEL is currently the largest linear accelerator using superconducting technology with 808 electromagnetic field cavities. The existing fault detection system focuses on the most severe known faults using heuristically tuned thresholds on selected physical parameters computed from measurements. In the large amount of cavity data, non-optimal and abnormal behavior is not always classified. The aim of this article is to describe an automatic anomaly detection system for the European XFEL to detect and store anomalies in the cavity behavior for further analysis. A parity space algorithm using a nonlinear model for the nominal behavior of each cavity is proposed. Due to its low computational complexity, this algorithm is suitable for an implementation on the existing data acquisition and control system based on FPGAs. The proposed fault detection scheme allows the classification of numerous data sets into faults, anomalies and nominal behavior. The evaluation on available data sets shows that a further distinction between anomalies and faults is possible, useful and might even lead to new insight into the formation of (possibly severe) faults during the operation of the system. © 2018

关键词： Fault detection Classification (of information) computational complexity Data acquisition Electromagnetic fields Linear accelerators Anomaly detection Anomaly detection systems Fault detection schemes Fault detection systems low computational complexity Parity spaces Physical parameters Superconducting technology

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Analysis of Vehicle Detection with WSN-Based Ultrasonic Sensors

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SENSORS 2014年第8期14卷 14050-14069页

作者： Jo, Youngtae Jung, Inbum Kangwon Natl Univ Dept Comp Informat & Commun Engn Chunchon 200701 Gangwondo South Korea

Existing traffic information acquisition systems suffer from high cost and low scalability. To address these problems, the application of wireless sensor networks (WSNs) has been studied, as WSN-based systems are highly scalable and have a low cost of installing and replacing the systems. Magnetic, acoustic and accelerometer sensors have been considered for WSN-based traffic surveillance, but the use of ultrasonic sensors has not been studied. The limitations of WSN-based systems make it necessary to employ power saving methods and vehicle detection algorithms with low computational complexity. In this paper, we model and analyze optimal power saving methodologies for an ultrasonic sensor and present a computationally-efficient vehicle detection algorithm using ultrasonic data. The proposed methodologies are implemented and evaluated with a tiny microprocessor on real roads. The evaluation results show that the low computational complexity of our algorithm does not compromise the accuracy of vehicle detection.

关键词： power saving low computational complexity ultrasonic sensors traffic information acquisition systems wireless sensor networks

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low-complexity Butterfly Integration Structure for MMSE-SIC SISO Detector

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WIRELESS PERSONAL COMMUNICATIONS 2013年第2期72卷 1187-1202页

作者： Wang, Huan-Chun Huang, De-Jhen Leon, Hernan Garron Wen, Jyh-Horng Natl Taiwan Univ Sci & Technol Dept Elect & Comp Engn Taipei Taiwan Ind Technol Res Inst Informat & Commun Res Labs Hsinchu Taiwan Tunghai Univ Dept Elect Engn Taichung 40704 Taiwan

In this paper, we propose a low-complexity butterfly integration structure (LCBIS) for the minimum mean square error-soft interference cancellation (MMSE-SIC) soft-in soft-out (SISO) detector, which is widely used for MIMO systems. Unlike the conventional MMSE-SIC SISO detector which performs matrix inverse operations, the LCBIS performs butterfly integration operations with low complexity. To develop the LCBIS SISO detector, we derive an integral expression for the extrinsic information of the conventional MMSE-SIC SISO detector, and then propose a butterfly integration structure to compute the integral expression efficiently. Without matrix inverse operations, LCBIS significantly reduces the complexity of the MMSE-SIC SISO detector. In addition, simulation results show that LCBIS can offer much better BER than the other SISO detectors which do not perform matrix inverse operations.

关键词： MIMO MMSE-SIC SISO detector Butterfly integration structure low computational complexity

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Biologically inspired adaptive intelligent secondary control for MGs under cyber imperfections

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IET CYBER-PHYSICAL SYSTEMS: THEORY & APPLICATIONS 2019年第4期4卷 341-352页

作者： Jafari, Mohammad Ghasemkhani, Amir Sarfi, Vahid Livani, Hanif Yang, Lei Xu, Hao Univ Calif Santa Cruz Dept Appl Math Jack Baskin Sch Engn Santa Cruz CA 95064 USA Univ Nevada Dept Comp Sci & Engn Reno NV 89557 USA Univ Nevada Dept Elect & Biomed Engn Reno NV 89557 USA

In this study, the authors investigate the secondary control of microgrids (MGs) in the presence of cyber imperfections such as delay and/or noise, and system disturbances. The existence of cyber imperfections and disturbance could bring in system uncertainty that will seriously degrade the effectiveness of most existing secondary control such as proportional-integral-derivative (PID), etc. To tackle these issues, a biologically-inspired reinforcement learning technique has been proposed which adjusts its parameters to the perturbed system setpoints generated by the cyber imperfections and system disturbances. The learning capability and low computational complexity of the proposed controller make it a promising approach to take cyber imperfections and system disturbances into account, where traditional control methodologies are not suitable due to their vulnerability to the cyber imperfections. First, an emotional learning-based secondary control structure is proposed, where the impacts of cyber imperfection and disturbance have been captured efficiently. Then, the real-time update laws are developed for generating the proper emotional signals (ESs) to stabilize the frequency and voltage. Ultimately, using the generated ESs, the secondary control of MGs is achieved. The Lyapunov analysis has been provided to prove the stability of the proposed design. Moreover, MATLAB/Simulink-based simulations demonstrate the effectiveness of the proposed algorithm.

关键词： control system synthesis stability Lyapunov methods three-term control distributed power generation power generation control learning (artificial intelligence) adaptive control neurocontrollers uncertain systems MATLAB Simulink-based simulations Lyapunov analysis emotional signals low computational complexity perturbed system set points generation uncertainty system proportional-integral-derivative biologically inspired reinforcement learning technique biologically inspired adaptive intelligent secondary control MGs cyber imperfection emotional learning-based secondary control structure system disturbances

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Reduced complexity sphere decoding

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WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2011年第12期11卷 1518-1527页

作者： Li, Boyu Ayanoglu, Ender Univ Calif Irvine Henry Samueli Sch Engn Dept Elect Engn & Comp Sci Ctr Pervas Commun & Comp Irvine CA 92697 USA

In multiple-input multiple-output (MIMO) systems, sphere decoding (SD) can achieve a performance equivalent to a full-search maximum likelihood decoding, with reduced complexity. Several researchers reported techniques that reduce the complexity of SD further. In this paper, a new technique that decreases the computational complexity of SD substantially, without sacrificing performance, is introduced. The reduction is accomplished by deconstructing the decoding metric to decrease the number of computations and by exploiting the structure of a lattice representation. Furthermore, an application of SD employing a proposed smart implementation with very low computational complexity is introduced. This application calculates the soft bit metrics of a bit-interleaved convolutional-coded MIMO system in an efficient manner. On the basis of the reduced complexity SD, the proposed smart implementation employs the initial radius acquired by zero-forcing decision feedback equalization, which ensures no empty spheres. Other than that, a technique of a particular data structure is also incorporated to efficiently reduce the number of executions carried out by SD. Simulation results show that these approaches achieve substantial gains in terms of the computational complexity for both uncoded and coded MIMO systems. Copyright (C) 2011 John Wiley & Sons, Ltd.

关键词： MIMO ML decoding SD low computational complexity

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DOA estimation based on reduced-rank multistage Wiener filter

DOA estimation based on reduced-rank multistage Wiener filte...

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7th International Congress of Information and Communication Technology (ICICT)

作者： Zhang, Ming Lu, Rui Zhu, Shitao Zhang, Anxue Xi An Jiao Tong Univ Xian 710049 Shaanxi Peoples R China

A new DOA estimator based on the reduced-rank multistage Wiener filter (MWF) is proposed this paper. This method estimates the DOAs of the impinging signals in the framework of beamforming and the number of sources (NOS) is hence not required. Besides improving performance over the classical subspace-based methods under small sample size condition, the new algorithm offers a significant reduction in computational complexity. In addition, a computation-free rank selection criterion is developed for the reduced-rank MWF, which plays the role of determining the NOS in the subspace-based methods. This criterion has better performance than the conventional information theoretic criteria when the sample size is small.

关键词： DOA estimation low computational complexity multistage Wiener filter reduced-rank processing

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Efficient Estimation of Carrier and Sampling Frequency Offsets in OFDM Systems

Efficient Estimation of Carrier and Sampling Frequency Offse...

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IEEE Wireless Communications and Networking Conference (WCNC)

作者： Murin, Yonathan Dabora, Ron Ben Gurion Univ Negev Dept Elect & Comp Engn Beer Sheva Israel

ISBN: (纸本)9781479930838

This work studies the problem of jointly estimating the carrier frequency offset (CFO) and sampling frequency offset (SFO) in orthogonal frequency-division multiplexing (OFDM) systems. Two scenarios are considered: known channel impulse response (CIR) and unknown CIR. It was shown in previous works that the exact joint maximum-likelihood estimate (MLE) of the CFO and the SFO requires a two-dimensional search. In this work, we present a new estimation method which uses the Taylor expansion of the MLE cost function, combined with the best linear unbiased estimator, to obtain an estimator which does not require such a search. Numerical simulations demonstrate that the new method approaches the corresponding Cramer-Rao bound for a wide range of signal-to-noise ratios, and have superior performance compared to all other existing methods for approximating the joint MLE solution, while maintaining a low computational complexity.

关键词： OFDM modulation frequency estimation maximum likelihood estimation radio networks search problems CFO Crame?r-Rao bound MLE cost function OFDM systems SFO Taylor expansion best linear unbiased estimator carrier frequency offset estimation channel impulse response exact joint maximum-likelihood estimate joint MLE solution low computational complexity numerical simulations orthogonal frequency-division multiplexing system sampling frequency offset estimation signal-to-noise ratios two-dimensional search unknown CIR Approximation methods computational complexity Maximum likelihood estimation OFDM Polynomials Signal to noise ratio signal to noise ratios maximum likelihood estimation Orthogonal frequency division multiplexing carrier frequency offset Taylor series complexity classes channel impulse response Cramer-Rao bounds tabu search Approximation method Radio networks Frequency estimation Polynomial

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Merged SLM Scheme for PAPR Reduction of OFDM System with low complexity

Merged SLM Scheme for PAPR Reduction of OFDM System with Low...

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IEEE Sarnoff Symposium

作者： Park, Sung-Ho Lee, Jong-Yeop Hong, Eon-Pyo Min, Seung-Wook Har, Dong-Soo Gwangju Inst Sci & Technol Dept Informat & Commun Kwangju South Korea Univ Sangmyung Div Comp Sci Seoul South Korea

ISBN: (纸本)9781424433810

Merged selected mapping (SLM) scheme is presented for reducing peak-to-average power ratio (PAPR) of an orthogonal frequency division multiplexing (OFDM). The concept of the proposed SLM scheme is based on a combination of advantages of the conventional low complexity SLM schemes by dividing inverse fast Fourier transform (IFFT) into k stage and remaining n-k stage and, then generating additional OFDM signal sequences without performing IFFT to the conventional SLM scheme. This scheme dramatically reduces computational complexity comparing with the conventional SLM schemes under the similar PAPR reduction performance.

关键词： low computational complexity orthogonal frequency division multiplexing (OFDM) peak-to-average power ratio (PAPR) selected mapping (SLM)

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Research on Algorithm of Segment and Classification of audio in Broadcast 10

Research on Algorithm of Segment and Classification of audio...

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10th International Symposium on computational Intelligence and Design (ISCID)

作者： Sun, Yuhang Zhou, Jian Commun Univ China Coll Informat Engn Beijing Peoples R China

ISBN: (纸本)9781538636756

There are two common classes of audio, speech and music, in broadcast. An algorithm of segment and classification of audio designed in this paper will be applied to audio equalizer in the digital audio broadcasting transmitter. The algorithm described is based on zero crossing rate and energy that are able to separated non-silence segments from audio, and on Modified low energy ratio (MLER) and maximum likelihood criterion, which provides the ability to distinguish the two classes, speech and music. Modified low energy ratio is obtained on the basis of energy resulting in low computational complexity, leading to runs easily in real time. Experiment results to data show performance with the accuracy rate of over 96%.

关键词： component segment classification features maximum likelihood criterion low computational complexity

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Reduced complexity Sphere Decoding

Reduced Complexity Sphere Decoding

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7th IEEE International Wireless Communications and Mobile Computing Conference (IWCMC)

作者： Li, Boyu Ayanoglu, Ender Univ Calif Irvine Henry Samueli Sch Engn Dept Elect Engn & Comp Sci Ctr Pervas Commun & Comp Irvine CA 92697 USA

ISBN: (纸本)9781424495375

In Multiple-Input Multiple-Output (MIMO) systems, Sphere Decoding (SD) can achieve performance equivalent to full search Maximum Likelihood (ML)decoding with reduced complexity. Several researchers reported techniques that reduce the complexity of SD further. In this paper, a new technique is introduced which decreases the computational complexity of SD substantially, without sacrificing performance. The reduction is accomplished by deconstructing the decoding metric to decrease the number of computations and exploiting the structure of a lattice representation. Simulation results show that this approach achieves substantial gains for the average number of real multiplications and real additions needed to decode one transmitted vector symbol. As an example,fora 4 x 4 MIMO system, the gains in the number of multiplications are 85% with 4-QAM and 90% with 64-QAM, at low SNR.

关键词： MIMO ML Decoding SD low computational complexity

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