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4th IEEE International Conference on Signal and Image Processing (ICSIP)

作者： Wang, Yuting Cao, Jian Wang, Jun Liang, Fan Sun Yat Sen Univ Dept Elect & Commun Engn Guangzhou Guangdong Peoples R China

ISBN: (纸本)9781728136608

The video coding standard, High efficiency Video Coding (HEVC), has come into view in these years. Compared with H.264/AVC, it can improve the performance by up to 50% bitrate saving. However, it also leads to a high encoding complexity. In order to decrease the complexity, we propose a new fast CU size decision and mode decision algorithm for HEVC intra coding. In particular, aiming at CU size decision, a joint method for classification and early termination is proposed according to gradient map and threshold function. In the process of mode decision, the number of checked intra prediction modes (IPM) is decreased based on multiple texture directions. Compared with the HEVC reference software HM 16.9, the proposed algorithm can save approximately 33.76% encoding time on average, which has better performance in time-saving than recent algorithms with slightly loss of BD-Rate.

关键词： HEVC intra prediction gradient fast algorithm

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Numerical approximation and fast evaluation of the overdamped generalized Langevin equation with fractional noise

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ESAIM-MATHEMATICAL MODELLING AND NUMERICAL ANALYSIS-MODELISATION MATHEMATIQUE ET ANALYSE NUMERIQUE 2020年第2期54卷 431-463页

作者： Fang, Di Li, Lei Univ Calif Berkeley Dept Math Berkeley CA 94720 USA Shanghai Jiao Tong Univ Inst Nat Sci Sch Math Sci MOE LSC Shanghai 200240 Peoples R China

The generalized Langevin equation (GLE) is a stochastic integro-differential equation that has been used to describe the movement of microparticles with sub-diffusion phenomenon. It has been proved that with fractional Gaussian noise (fGn) mostly considered by biologists, the overdamped Generalized Langevin equation satisfying fluctuation dissipation theorem can be written as a fractional stochastic differential equation (FSDE). In this work, we present both a direct and a fast algorithm respectively for this FSDE model in order to numerically study ergodicity. The strong orders of convergence are proven for both schemes, where the role of the memory effects can be clearly observed. We verify the convergence theorems using linear forces, and then verify the convergence to Gibbs measure algebraically for the double well potentials in both 1D and 2D setups. Our work is new in numerical analysis of FSDEs and provides a useful tool for studying ergodicity. The idea can also be used for other stochastic models involving memory.

关键词： Generalized Langevin equation fractional Brownian motion fractional stochastic differential equations fast algorithm strong convergence

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fast Radix-32 Approximate DFTs for 1024-Beam Digital RF Beamforming

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IEEE ACCESS 2020年 8卷 96613-96627页

作者： Madanayake, Arjuna Cintra, Renato J. Akram, Najath Ariyarathna, Viduneth Mandal, Soumyajit Coutinho, Vitor A. Bayer, Fabio M. Coelho, Diego Rappaport, Theodore S. Florida Int Univ Elect & Comp Engn Dept Miami FL 33199 USA Univ Fed Pernambuco Dept Estat Signal Proc Grp BR-50670901 Recife PE Brazil Case Western Reserve Univ Elect Comp & Syst Engn Dept Cleveland OH 44106 USA Univ Fed Pernambuco Dept Estat Signal Proc Grp BR-50670901 Recife PE Brazil Univ Fed Santa Maria Dept Stat BR-97105900 Santa Maria RS Brazil Univ Fed Santa Maria LACESM BR-97105900 Santa Maria RS Brazil NYU Tandon Sch Engn Dept Elect Engn NYU Wireless Brooklyn NY 11220 USA Univ Calgary Dept Elect & Comp Engn Calgary AB T2N 1N4 Canada

The discrete Fourier transform (DFT) is widely employed for multi-beam digital beamforming. The DFT can be efficiently implemented through the use of fast Fourier transform (FFT) algorithms, thus reducing chip area, power consumption, processing time, and consumption of other hardware resources. This paper proposes three new hybrid DFT 1024-point DFT approximations and their respective fast algorithms. These approximate DFT (ADFT) algorithms have significantly reduced circuit complexity and power consumption compared to traditional FFT approaches while trading off a subtle loss in computational precision which is acceptable for digital beamforming applications in RF antenna implementations. ADFT algorithms have not been introduced for beamforming beyond N = 32, but this paper anticipates the need for massively large adaptive arrays for future 5G and 6G systems. Digital CMOS circuit designs for the ADFTs show the resulting improvements in both circuit complexity and power consumption metrics. Simulation results show similar or lower critical path delay with up to 48.5% lower chip area compared to a standard Cooley-Tukey FFT. The time-area and dynamic power metrics are reduced up to 66.0%. The 1024-point ADFT beamformers produce signal-to-noise ratio (SNR) gains between 29.2-30.1 dB, which is a loss of <= 0.9 dB SNR gain compared to exact 1024-point DFT beamformers (worst case) realizable at using an FFT.

关键词： Discrete Fourier transforms Approximation algorithms Array signal processing Signal processing algorithms Computational complexity MIMO communication Fourier transform discrete fourier transform approximation VLSI DFT FFT radix fast algorithm beamforming beamsteering 5G MIMO massive MIMO

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Use of dynamic adaptive chemistry and dynamic cell clustering in computational fluid dynamics to accelerate calculation of combustion simulation of diesel engine

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FUEL 2023年第1期338卷

作者： Feng, Shiquan Zhang, Hongmei Changshu Inst Technol Sch Automot Engn Suzhou Jiangsu Peoples R China

Based on the theory of dynamic adaptive chemistry and dynamic cell clustering, a 3D model for fuel combustion in the cylinder is constructed to study the fast calculation algorithm to accelerate the engine combustion simulation and analyze the impacts of the basic structure and the main parameters of dynamic adaptive chemistry and dynamic cell clustering on diesel engine simulation. It is found that the error threshold value of the dynamic adaptive chemistry algorithm should be set appropriately to ensure the accuracy of the simulation, and the dynamic adaptive chemistry algorithm should employ different initial search species and threshold values to meet different research objectives. Regarding the dynamic cell clustering algorithm, the data accuracy in the overall spatial range can be guaranteed, but the local location information will be missing, which will have a great impact on the prediction of pollutants. Therefore, suitable cell clustering conditions should be selected to meet the requirements of different targets.

关键词： Simulation Engine Combustion simulation fast algorithm

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A fast State-Based Peridynamic Numerical Model

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Communications in Computational Physics 2020年第1期27卷 274-291页

作者： Ning Du Xu Guo Hong Wang School of Mathematics Shandong UniversityJinan 250100China Department of Mathematics The Chinese University of Hong KongShatinN.T.Hong Kong Department of Mathematics University of South CarolinaSCUSA

The peridynamic(PD)theory is a reformulation of the classical theory of continuum solid mechanics and is particularly suitable for the representation of discontinuities in displacement fields and the description of cracks and their evolution in materials,which the classical partial differential equation(PDE)models tend to fail to ***,the PD models yield numerical methods with dense stiffness matrices which requires O(N^(2))memory and O(N^(3))computational complexity where N is the number of spatial ***,the PD models are deemed to be computationally very expensive especially for problems in multiple space ***-based PD models,which were developed lately,can be treated as a great improvement of the previous bond-based PD *** state-based PD models have more complicated structures than the bond-based PD *** this paper we develop a fast collocation method for a state-based linear PD model by exploring the structure of the stiffness matrix of the numerical *** method has an O(N)memory requirement and computational complexity of O(N log N)per Krylov sub-space *** methods are presented to show the utility of the method.

关键词： State-based peridynamic model fast algorithm collocation method stiffness matrix

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fast Nonseparable Gaussian Stochastic Process With Application to Methylation Level Interpolation

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JOURNAL OF COMPUTATIONAL AND GRAPHICAL STATISTICS 2020年第2期29卷 250-260页

作者： Gu, Mengyang Xu, Yanxun Johns Hopkins Univ Dept Appl Math & Stat Baltimore MD USA Univ Calif Santa Barbara Dept Stat & Appl Probabil Santa Barbara CA 93106 USA

Gaussian stochastic process (GaSP) has been widely used as a prior over functions due to its flexibility and tractability in modeling. However, the computational cost in evaluating the likelihood is , where n is the number of observed points in the process, as it requires to invert the covariance matrix. This bottleneck prevents GaSP being widely used in large-scale data. We propose a general class of nonseparable GaSP models for multiple functional observations with a fast and exact algorithm, in which the computation is linear (O(n)) and exact, requiring no approximation to compute the likelihood. We show that the commonly used linear regression and separable models are special cases of the proposed nonseparable GaSP model. Through the study of an epigenetic application, the proposed nonseparable GaSP model can accurately predict the genome-wide DNA methylation levels and compares favorably to alternative methods, such as linear regression, random forest, and localized Kriging method. The of this article are online and the algorithm for fast computation is implemented in the fastGaSP R package on CRAN. Supplemental materials for this article are available online.

关键词： Exact computation fast algorithm Gaussian Markov random field Methylation levels imputation Model unification Multiple functional data

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Research Progress on Discretization of Linear Canonical Transform

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Journal of Beijing Institute of Technology 2021年第3期30卷 205-216页

作者： Yannan Sun Bingzhao Li Ran Tao School of Mathematical Sciences Jiangsu University School of Mathematics and Statistics Beijing Institute of Technology School of Information and Electronics Beijing Institute of Technology

Linear canonical transformation(LCT) is a generalization of the Fourier transform and fractional Fourier transform. The recent research has shown that the LCT is widely used in signal processing and applied mathematics, and the discretization of the LCT becomes vital for the applications of LCT. Based on the development of discretization LCT, a review of important research progress and current situation is presented, which can help researchers to further understand the discretization of LCT and can promote its engineering application. Meanwhile, the connection among different discretization algorithms and the future research are given.

关键词： linear canonical transform(LCT) discrete linear canonical transform sampling Wigner-Ville distribution fast algorithm

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Wide-scale identification of novel/eliminated genes responsible for evolutionary transformations

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BIOLOGY DIRECT 2023年第1期18卷 45-45页

作者： Lyubetsky, Vassily A. Rubanov, Lev I. Tereshina, Maria B. Ivanova, Anastasiya S. Araslanova, Karina R. Uroshlev, Leonid A. Goremykina, Galina I. Yang, Jian-Rong Kanovei, Vladimir G. Zverkov, Oleg A. Shitikov, Alexander D. Korotkova, Daria D. Zaraisky, Andrey G. Russian Acad Sci Inst Informat Transmiss Problems Kharkevich Inst 19 Build 1Bolshoy Karetny Per Moscow 127051 Russia Lomonosov Moscow State Univ Dept Mech & Math Kolmogorova Str 1 Moscow 119234 Russia Russian Acad Sci Shemyakin Ovchinnikov Inst Bioorgan Chem 16-10 Miklukho Maklaya Str Moscow 117997 Russia Pirogov Russian Natl Res Med Univ Moscow Russia Scripps Res Inst Dept Mol Med La Jolla CA USA Russian Acad Sci Engelhardt Inst Mol Biol 32 Vavilova Str Moscow 119991 Russia Plekhanov Russian Univ Econ Stremyanny Lane 36 Moscow Russia Sun Yat Sen Univ Affiliated Hosp 1 Adv Med Technol Ctr Zhongshan Sch Med Guangzhou 510080 Peoples R China Sun Yat Sen Univ Zhongshan Sch Med Dept Genet & Biomed Informat Guangzhou 510080 Peoples R China Ecole Polytech Fed Lausanne Global Hlth Inst Sch Life Sci Lausanne Switzerland

BackgroundIt is generally accepted that most evolutionary transformations at the phenotype level are associated either with rearrangements of genomic regulatory elements, which control the activity of gene networks, or with changes in the amino acid contents of proteins. Recently, evidence has accumulated that significant evolutionary transformations could also be associated with the loss/emergence of whole genes. The targeted identification of such genes is a challenging problem for both bioinformatics and evo-devo *** solve this problem we propose the WINEGRET method, named after the first letters of the title. Its main idea is to search for genes that satisfy two requirements: first, the desired genes were lost/emerged at the same evolutionary stage at which the phenotypic trait of interest was lost/emerged, and second, the expression of these genes changes significantly during the development of the trait of interest in the model organism. To verify the first requirement, we do not use existing databases of orthologs, but rely purely on gene homology and local synteny by using some novel quickly computable conditions. Genes satisfying the second requirement are found by deep RNA sequencing. As a proof of principle, we used our method to find genes absent in extant amniotes (reptiles, birds, mammals) but present in anamniotes (fish and amphibians), in which these genes are involved in the regeneration of large body appendages. As a result, 57 genes were identified. For three of them, c-c motif chemokine 4, eotaxin-like, and a previously unknown gene called here sod4, essential roles for tail regeneration were demonstrated. Noteworthy, we established that the latter gene belongs to a novel family of Cu/Zn-superoxide dismutases lost by amniotes, *** present a method for targeted identification of genes whose loss/emergence in evolution could be associated with the loss/emergence of a phenotypic trait of interest. In a proof-of-principl

关键词： Loss or emergence of genes Loss or emergence of the phenotypic traits Changes of gene expression Xenopus tadpoles tail regeneration Gene regulators of regeneration Gene knockdown fast algorithm Effective computer program

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A Multithreaded algorithm for the Computation of Sample Entropy

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algorithmS 2023年第6期16卷 299-299页

作者： Manis, George Bakalis, Dimitrios Sassi, Roberto Univ Ioannina Sch Engn Dept Elect & Comp Engn Ioannina 45110 Greece Univ Milan Dipartimento Informat I-20133 Milan Italy

Many popular entropy definitions for signals, including approximate and sample entropy, are based on the idea of embedding the time series into an m-dimensional space, aiming to detect complex, deeper and more informative relationships among samples. However, for both approximate and sample entropy, the high computational cost is a severe limitation. Especially when large amounts of data are processed, or when parameter tuning is employed premising a large number of executions, the necessity of fast computation algorithms becomes urgent. In the past, our research team proposed fast algorithms for sample, approximate and bubble entropy. In the general case, the bucket-assisted algorithm was the one presenting the lowest execution times. In this paper, we exploit the opportunities given by the multithreading technology to further reduce the computation time. Without special requirements in hardware, since today even our cost-effective home computers support multithreading, the computation of entropy definitions can be significantly accelerated. The aim of this paper is threefold: (a) to extend the bucket-assisted algorithm for multithreaded processors, (b) to present updated execution times for the bucket-assisted algorithm since the achievements in hardware and compiler technology affect both execution times and gain, and (c) to provide a Python library which wraps fast C implementations capable of running in parallel on multithreaded processors.

关键词： entropy sample entropy fast algorithm parallel algorithm bucket-assisted algorithm

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fast evaluation for the two-dimensional nonlinear coupled time-space fractional Klein-Gordon-Zakharov equations

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APPLIED MATHEMATICS LETTERS 2021年 118卷 107148-107148页

作者： Jia, Junqing Xu, Huanying Jiang, Xiaoyun Shandong Univ Sch Math Jinan 250100 Peoples R China Shandong Univ Sch Math & Stat Weihai 264209 Peoples R China

In this paper, we develop a fast algorithm to solve the two-dimensional nonlinear coupled time-space fractional Klein-Gordon-Zakharov (KGZ) equations. The L2 - 1(sigma) method based on an efficient sum-of-exponentials (SOE) approximation and a Fourier spectral method are used to approximate the time and space direction, respectively. And we use the previous time levels to deal with the nonlinear terms to obtain a linearized numerical scheme. Finally, a numerical example is given to show that our numerical method is of second order accuracy in time, spectral accuracy in space and the fast algorithm is effective. (C) 2021 Elsevier Ltd. All rights reserved.

关键词： Fractional Klein-Gordon-Zakharov equations L-2-1(sigma) method Fourier spectral method fast algorithm

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