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A parallel recurrence method for the fast computation of Zernike moments

APPLIED MATHEMATICS AND COMPUTATION 2012年第4期219卷 1549-1561页

作者： Qin, Huafeng Qin, Lan Xue, Lian Yu, Chengbo Chongqing Univ Coll Optoelect Engn Minist Educ Key Lab Optoelect Technol & Syst Chongqing 400030 Peoples R China Chongqing Univ Coll Optoelect Engn Chongqing 400030 Peoples R China Chongqing Univ Technol Coll Elect & Automat Chongqing Peoples R China

This paper presents a parallel recursive method for the computation of Zernike moments from a digital image. The proposed method can reduce the computational complexity of the Zernike radial polynomials by introducing a novel recurrence relation, and be applicable to either the computation of a single Zernike moment or entire set of Zernike moments. The fast computation is achieved because it involves less addition and multiplication operations and is executed in parallel. Moreover, the single Zernike moment can be obtained with employing partial Zernike moments of lower orders. The experiments are carried out to evaluate the performance of the proposed method using binary and grayscale images. The experimental results show that the proposed method takes the shortest time in computing the Zernike moments of a specific order <= 28 as well as the entire Zernike moments of orders <= 70. (C) 2012 Elsevier Inc. All rights reserved.

关键词： Zernike moments Fast computation recursive method Image reconstruction accuracy Vectorization

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An effort saving method to establish global aerodynamic model using CFD

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AIRCRAFT ENGINEERING AND AEROSPACE TECHNOLOGY 2022年第11期94卷 1-19页

作者： Xie, Jingfeng Huang, Jun Song, Lei Fu, Jingcheng Lu, Xiaoqiang Beihang Univ Sch Aeronaut Sci & Engn Beijing Peoples R China

Purpose The typical approach of modeling the aerodynamics of an aircraft is to develop a complete database through testing or computational fluid dynamics (CFD). The database will be huge if it has a reasonable resolution and requires an unacceptable CFD effort during the conceptional design. Therefore, this paper aims to reduce the computing effort required via establishing a general aerodynamic model that needs minor parameters. Design/methodology/approach The model structure was a preconfigured polynomial model, and the parameters were estimated with a recursive method to further reduce the calculation effort. To uniformly disperse the sample points through each step, a unique recursive sampling method based on a Voronoi diagram was presented. In addition, a multivariate orthogonal function approach was used. Findings A case study of a flying wing aircraft demonstrated that generating a model with acceptable precision (0.01 absolute error or 5% relative error) costs only 1/54 of the cost of creating a database. A series of six degrees of freedom flight simulations shows that the model's prediction was accurate. Originality/value This method proposed a new way to simplify the model and recursive sampling. It is a low-cost way of obtaining high-fidelity models during primary design, allowing for more precise flight dynamics analysis.

关键词： Aerodynamic Modeling CFD recursive method

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Introducing adaptive neurofuzzy modeling with online learning method for prediction of time-varying solar and geomagnetic activity indices

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EXPERT SYSTEMS WITH APPLICATIONS 2010年第12期37卷 8267-8277页

作者： Mirmomeni, Masoud Lucas, Caro Moshiri, Behzad Araabi, Babak Nadjar Univ Tehran Sch Elect & Comp Engn Univ Coll Engn Control & Intelligent Proc Ctr Excellence Tehran *** Iran Sch Cognit Sci Inst Studies Theoret Phys & Math Tehran Iran

Research in space weather has in recent years become an active field of research requiring international cooperation because of its importance in hazard warning especially for satellite technology and power utility systems. The time-varying sun as the main source of space weather impacts the Earth's magnetosphere by emitting hot magnetized plasma called solar wind into interplanetary space. The emission of Solar Energetic Particles (SEPs) and consequently the magnitude of Interplanetary Magnetic Field (IMF) vary almost periodically with an approximate life cycle of 11 years. It is shown that the solar and geomagnetic activity indices have complex behavior often characterizable as quasi-periodic or even chaotic, which causes the long-term prediction to be a conundrum. Moreover, solar and geomagnetic activity indices and their chaotic characteristics vary abruptly during solar and geomagnetic storms. This variation depicts the difficulties in modeling and long-term prediction of solar and geomagnetic storms. On the other hand, neural networks and related neurofuzzy tools as general function approximators have been the subjects of interest due to their many practical applications in modeling and predicting complex phenomena. However, most of these systems are trained by algorithms that need to be carried out by an off-line data set which influence their performance in prediction of time-varying solar and geomagnetic activity indices. This paper proposes an adaptive neurofuzzy approach with a recursive learning algorithm for modeling and prediction of space weather indices which fulfill requirements of prediction of time-varying solar and geomagnetic activities for long time spans. The obtained results depict the power of the proposed method in online prediction of time-varying solar and geomagnetic activity indices. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Space weather Solar activity Geomagnetic disturbance Online learning recursive method Neurofuzzy modeling

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Accurate error rate estimate using moment method for optimum diversity combining and MMSE equalisation in digital cellular mobile radio

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IEE PROCEEDINGS-COMMUNICATIONS 2002年第3期149卷 157-165页

作者： Lin, SC Fu Jen Catholic Univ Dept Elect Engn Taipei 24205 Taiwan

Research is presented which provides fast and accurate performance analysis for optimum diversity combining and equalisation with quadrature amplitude modulation (QAM) over mobile radio channels with frequency-selective fading. The performance of optimum diversity combining and equatisation over a noise-limited channel has been presented previously, but the error rate calculation was based on the upper bound method. The accurate performance of such a diversity receiver has not been evaluated completely. An analysis is present in which the upper bound method for each individual run is replaced by the moment method in a quasi-analytical (QA) Monte Carlo simulation. Simulation techniques are first used to evaluate the residual ISI after equalisation, and then moments of this ISI are calculated using a very fast and accurate recursive method of computation. Based on these moments, the author uses the series expansion to obtain the error rate of the system. The multipath channel is treated as quasistatic and the system, including the channel, is assumed to be linear. Minimum mean-square-error (MMSE) equalisation techniques with linear and decision-feedback structures are considered and compared in the analysis. A method is defined for finding the transfer function of the infinitely long decision feedback equaliser, which requires greater computational complexity. Numerical results show that by using the moment method the performance can be improved significantly in comparison to the upper bound approach.

关键词： least mean squares methods computational complexity decision feedback equaliser series expansion approximations optimum diversity combining MMSE equalisation Monte Carlo simulation method of moments diversity reception minimum mean-square-error error rate estimate digital cellular mobile radio Mobile radio systems decision feedback equalisers transfer functions Monte Carlo methods digital simulation Interpolation and function approximation (numerical analysis) DFE error probability transfer function diversity receiver frequency-selective fading Communication channel equalisation and identification error statistics noise-limited channel Other topics in statistics digital radio quadrature amplitude modulation error rate cellular radio series expansion mobile radio channels performance analysis recursive method multipath channels multipath channel upper bound method moment method

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Complex-Valued Adaptive Filtering Based on the Random Fourier Features method

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II-EXPRESS BRIEFS 2020年第10期67卷 2284-2288页

作者： Xiong, Kui Zhang, Yu Wang, Shiyuan Southwest Univ Coll Elect & Informat Engn Chongqing Key Lab Nonlinear Circuits & Intelligen Chongqing 400715 Peoples R China Southwest Univ Fac Comp & Informat Sci Chongqing 400715 Peoples R China

The complex kernel adaptive filters (CKAFs) developed in complex reproducing kernel Hilbert space (RKHS) improve the performance of complex linear adaptive filters, but result in large burdens of computation and memory. To address these issues, a novel complex random Fourier features mapping (CRFFM) is proposed to approximate the kernel-induced mapping by applying the complexification of real RKHSs, and thus projects the complex-valued data from the original data space into the fixed-dimensional complex random Fourier features space (RFFS). To combat complex-valued non-Gaussian noises, a complex Cauchy loss function is presented, and the complex random Fourier features recursive complex Cauchy (CRFFRCC) algorithm is therefore proposed by the combination of CRFFM and the stochastic recursive method. The proposed CRFFRCC with a linear filter structure can reduce the computational and space complexities of CKAFs, significantly. Monte Carlo simulations conducted in the complex-valued nonlinear channel equalization validate the superiorities of CRFFRCC.

关键词： Kernel Signal processing algorithms Complexity theory Adaptive systems Probability density function Filtering Complex kernel adaptive filter random Fourier features complex Cauchy loss recursive method complexity

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A method for exact reliability of consecutive 2-out-of-(r,r)-from-(n,n):F system

A method for exact reliability of consecutive 2-out-of-(<i>r...

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13th ISSAT International Conference on Reliabitity and Quality in Design

作者： Higashiyama, Yoichi Rumchev, Ventsi Ehime Univ Dept Elect & Elect Engn Matsuyama Ehime 7808577 Japan Curtin Univ Technol Dept Math & Stat Perth WA 6845 Australia

ISBN: (纸本)9780976348627

A new reliability model, consecutive 2-out-of-(r, r) -from- (n,n):F model, is proposed. The consecutive 2-out-of- (r, r) - from(n, n) :F system consists of a square grid of side n (containing of n(2) components) such that the system fails if and only if there is at least one square of side r which includes at least two components among them. An algorithm is given for computing the reliability of the system with unequal component probabilities. The algorithm depends on the one-to-one correspondence relation between the representation of the systems and the class of 0-1 matrices having no two or more 0's at any square of side r.

关键词： consecutive 2-out-of-(r,r)-from-(n,n): F system System reliability recursive method

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A novel recurrence method for the fast computation of Zernike moments

A novel recurrence method for the fast computation of Zernik...

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2nd International Conference on Frontiers of Manufacturing and Design Science (ICFMD 2011)

作者： Qin, Huafeng Qin, Lan Liu, Jun Chongqing Univ Key Lab Optoelect Technol & Syst Minist Educ Coll Optoelect Engn Chongqing 400030 Peoples R China

ISBN: (纸本)9783037852828

A new method is proposed for fast computation of Zernike moments. This method presents a recursive relation to compute the entire set of Zernike moments. The fast computation is achieved because it involves less addition and multiplication operations. The experimental results show that the proposed method for the fast computation of Zernike moments is much more efficient than existing fast methods in most cases.

关键词： Zernike Moments Fast Computation recursive method Feature Representation Image Reconstruction Accuracy

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New method for the failure probability of strict circular consecutive-k-out-of-n:F system

New method for the failure probability of strict circular co...

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12th World Multi-Conference on Systemics, Cybernetics and Informatics/14th International Conference on Information Systems Analysis and Synthesis

作者： Higashiyama, Yoichi Rumchev, Ventsi Ehime Univ Dept Elect & Elect Engn Matsuyama Ehime 7908577 Japan Curtin Univ Technol Dept Math & Stat Perth WA 6845 Australia

ISBN: (纸本)9781934272350

A recursive formula is given for calculating the failure probability for circular consecutive-k-out-of-n:F systems such that isolated strings of failures of length less than k (which do not cause system failure) do not occur, or are immediately corrected;ie, when system failure occurs it is because all failures present are in strings of length at least k. New method gives the failure probability function of circular strict system with time complexity O(nk(2)).

关键词： Strict circular consecutive-k-out-of-n:F system System failure probability recursive method

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Fast method to compute the reliability of consecutive k-out-of-r-from-n:F system under the condition of r <2k

Fast Method to compute the reliability of consecutive <i>k</...

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16th ISSAT International Conference on Reliability and Quality in Design

作者： Higashiyama, Yoichi Chang, Jian Zhuo Rumchev, Ventsi Ehime Univ Dept Elect & Elect Engn Matsuyama Ehime 7908577 Japan Curtin Univ Technol Dept Math & Stat Perth WA 6845 Australia

ISBN: (纸本)9780976348665

A consecutive k-out-of- r -from-n :F system consists of 71 ordered components such that the system fails if and only if there are r consecutive components at least of which are failed. Such systems arise in quality-control problems and inspection procedures as well as in radar detection. This paper studies the reliability of a linear consecutive k-out-of-r-from-n :F system in the general case when the component probabilities can be different from each other. New recursive equation is derived for explicit solution of such general system, which required O(n) computing time. The results of some computational experiments are also described.

关键词： consecutive k-out-of-r-from-n:F system exact solution recursive method

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Study on the static properties of spiral springs under static loading

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Applied Mathematics and Mechanics(English Edition) 2021年第11期42卷 1571-1580页

作者： Zhixiang LI Zhen ZHAO Caishan LIU Qingyun WANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China

Spiral springs have a wide range of applications in various *** a result of the complexity of friction,few theoretical analyses of spring belts under static loading have been carried *** the piecewise smooth property of the whole contact area,a simplified static model of spiral springs under loading is established in this ***,three main stress and friction distribution areas of the spring belt are proposed,namely,internal,transitional,and external *** the outermost side of the spring is not subject to any pressure,a recursive method is adopted from the outside to the *** model provides the parameter conditions,i.e.,the internal and external forces are independent or ***,the case that the whole contact region of the spring belt has one subregion,two subregions,and three subregions is *** model gives a theoretical basis for the parameter optimization of spiral springs.

关键词： spiral spring simplified static model recursive method piecewise smooth feature

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