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Local voxelizer:A shape descriptor for surface registration

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Computational Visual Media 2015年第4期1卷 279-289页

作者： peng song School of Computer Science and Technology University of Science and Technology of China

Surface registration brings multiple scans into a common coordinate system by aligning their overlapping components. This can be achieved by finding a few pairs of matched points on different scans using local shape descriptors and employing the matches to compute transformations to produce the alignment. By defining a unique local reference frame(LRF) and attaching an LRF to shape descriptors,the transformation can be computed using only one match based on aligning the LRFs. This paper proposes a local voxelizer descriptor,and the key ideas are to define a unique LRF using the support around a basis point,to perform voxelization for the local shape within a cubical volume aligned with the LRF,and to concatenate local features extracted from each voxel to construct the descriptor. An automatic rigid registration approach is given based on the local voxelizer and an expanding strategy that merges descriptor representations of aligned scans. Experiments show that our registration approach allows the acquisition of 3D models of various objects,and that the local voxelizer is robust to mesh noise and varying mesh resolution,in comparison to two state-of-the-art shape descriptors.

关键词： shape descriptor surface registration scan alignment 3D reconstruction

Mechanistic insights into homogeneous electrocatalytic reaction for energy storage using finite element simulation

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Chinese Journal of Chemical Engineering 2022年第2期35卷 285-296页

作者： peng song Yan Li Shuang Yin Beijing Key Laboratory for Green Catalysis and Separation Department of Environmental and Chemical EngineeringBeijing University of TechnologyBeijing 100124China

The application of homogeneous electrocatalytic reactions in energy storage and conversion has driven surging interests of researchers in exploring the reaction mechanisms of molecular *** this paper,homogeneous electrocatalytic reaction between hydroxymethylferrocene(HMF)and L-cysteine is intensively investigated by cyclic voltammetry and square wave voltammetry for which,the secondorder rate constant(k_(ec))of the chemical reaction between HMF^(+)and L-cysteine is determined via a 1D homogeneous electrocatalytic reaction model based on finite element *** corresponding k_(ec)(1.1(mol·m^(-3))^(-1)·s^(-1))is further verified by linear sweep voltammograms under the same *** wave voltammetry parameters including potential frequency(f),increment(Estep)and amplitude(ESW)have been comprehensively investigated in terms of the voltammetric waveform transition of homogeneous electrocatalytic ***,the effect of potential frequency and increment is in accordance with the potential scan rate in cyclic voltammetry and the increase of pulsed potential amplitude results in a conspicuous split oxidative peaks ***,the proposed methodology of k_(ec)prediction is examined by hydroxyethylferrocene(HEF)and *** present work facilitates the understanding of homogeneous electrocatalytic reaction for energy storage purpose,especially in terms of electrochemical kinetics extraction and flow battery design.

关键词： Homogeneous electrocatalytic reaction Electrochemical kinetics Square wave voltammetry Finite element modelling Energy storage

Research on the Bit Synchronization Algorithm and Multiplexing Technology in GNSS Receiver

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China Communications 2014年第A02期11卷 30-36页

作者： QI Jianzhong song peng School of Computer and Communication Engineering University of Science and Technology Beijing Beijing 100083 ER. China North China University of Technology Beijing 100041 P. R. China

In this paper, the bit synchronization algorithms in GNSS receiver are introduced, including the traditional histogram method, K-P algorithm and Viterbi algorithm. The FPGA implementation is also included. A novel time division multiplexing technology （TDM） based on multi-channel shared synchronizer is proposed in this paper to solve the constrained hardware resource problem of multi-system satellite navigation receiver. Through the using of control state machine and data register structure, we realize the multiplexing of bit synchronizer of navigation receiver, which saves the hardware resource. After the experiment, it can be verified that the receiver based on the bit synchronization and multiplexing technology can correctly restore the navigation information.

关键词： bit synchronization carrier-to-noiseratio multiplexing GNSS

A generalized L_2-discrepancy for cubature and uncertainty quantification of nonlinear structures

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Science China(Technological Sciences) 2016年第6期59卷 941-952页

作者： CHEN Jian Bing song peng Yan State Key Laboratory of Disaster Reduction in Civil Engineering & School of Civil Engineering Tongji University College of Civil Engineering and Architecture Hebei University

The numerical method for multi-dimensional integrals is of great importance, particularly in the uncertainty quantification of engineering structures. The key is to generate representative points as few as possible but of acceptable accuracy. A generalized L2（GL2）-discrepancy is studied by taking unequal weights for the point set. The extended Koksma-Hlawka inequality is discussed. Thereby, a worst-case error estimate is provided by such defined GL2-discrepancy, whose dosed-form expression is available. The characteristic values of GL2-discrepancy are investigated. An optimal strategy for the selection of the representative point sets with a prescribed cardinal number is proposed by minimizing the GL2-discrepancy. The three typical examples of the multi-dimensional integrals are investigated. The stochastic dynamic response analysis of a nonlinear structure is then studied by incorporating the proposed method into the probability density evolution method. It is shown that the proposed method is advantageous in achieving tradeoffs between the efficiency and accuracy of the exemplified problems. Problems to be further studied are discussed.

关键词： Koksma-Hlawka inequality cubature L2-discrepancy nonlinear structure stochastic dynamics

Laplacian Speech Model and Soft Decision Based MMSE Estimator for Noise Power Spectral Density in Speech Enhancement

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Chinese Journal of Electronics 2018年第6期27卷 1214-1220页

作者： OU Shifeng song peng GAO Ying School of Science and Technology for Opto-electronic Information Yantai University School of Computer and Control Engineering Yantai University

The estimation of noise Power spectral density(PSD) is a very crucial issue for speech enhancement as a result of its significant effect on the quality and intelligibility of the enhanced speech. Most of the existing estimators for noise PSD try to employ Gaussian speech priors, which, however, have been proven inconsistent with the reality. We derived an effective solution to this problem of estimating noise PSD in the Minimum mean square error(MMSE) sense when the speech component is modeled by a Laplacian distribution. Meanwhile, the soft decision technique instead of the hard Voice activity detection(VAD) is evolved into our algorithm, which can automatically makes the estimation unbiased without requiring a bias compensation. The performance of the proposed method is tested by several objective and subjective measures under various stationary and nonstationary noise environments. The results confirm that our method achieves good performance for all the noise conditions and Signalnoise-ratio(SNR) settings.

关键词： Noise PSD estimation Speech enhancement Laplacian speech model Soft decision

Ultrasound Imaging of Pipeline Crack Based on Composite Transducer Array

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Chinese Journal of Mechanical Engineering 2018年第5期31卷 25-34页

作者： Shou-peng song Ying-Jie Ni Department of Instrument Science and Engineering School of Mechanical Engineering Jiangsu University

Cracks, especially small cracks are di cult to be detected in oil and gas transportation pipelines buried underground or covered with layers of material by using the traditional ultrasonic inspection techniques. Therefore, a new com?posite ultrasonic transducer array with three acoustic beam incidence modes is developed. The space model of the array is also established to obtain the defect reflection point location. And the crack ultrasound image is thus formed through a series of small cubical elements expanded around the point locations by using the projection of binariza?tion values extracted from the received ultrasonic echo signals. Laboratory experiments are performed on a pipeline sample with di erent types of cracks to verify the e ectiveness and performance of the proposed technique. From the image, the presence of small cracks can be clearly observed, in addition to the sizes and orientations of the cracks. The proposed technique can not only inspect common flaws, but also detect cracks with various orientations, which is helpful for defect evaluation in pipeline testing.

关键词： Composite transducer array Ultrasound imaging Crack NDT&E

Soft Decision Based Gaussian-Laplacian Combination Model for Noisy Speech Enhancement

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Chinese Journal of Electronics 2018年第4期27卷 827-834页

作者： OU Shifeng song peng GAO Ying School of Science and Technology for Opto-electronic Information Yantai University School of Computer and Control Engineering Yantai University

One of the key issues of noisy speech enhancement technique is to achieve appropriate statistical distributions to model the clean speech and noise signals accurately. Most of the existing algorithms try to employ a sole model assumption in transform domain, which, however, has been proven to being contrary with the fact. To address this problem, the statistical properties of clean speech as well as several noise signals are analyzed using actual data in Discrete cosine transform(DCT) domain, and the study indicates the statistic of clean speech DCT coefficients tending to fall somewhere in between the Gaussian and Laplacian distribution. Based on the results,a novel speech enhancement algorithm is proposed using Gaussian-Laplacian combination model, whose core is employing a linear combination of Gaussian and Laplacian distribution to model the statistic of clean speech DCT coefficients. The corresponding weights of either distribution to the combination model are adaptively adjusted in terms of the probability of each hypothesis, which is estimated based on a soft decision technique by using Bayesian theorem. Through a number of objective and subjective tests,we compare the performance of the proposed algorithm with other recent model based approaches and have found that our algorithm is superior to the related approaches at all testing environments.

关键词： Speech enhancement Soft decision Speech distortion Combination model

Comparison of resonant current regulators for DFIG during grid voltage distortion

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Journal of Zhejiang University-Science C(Computers and Electronics) 2013年第12期14卷 953-965页

作者： Yi-peng song Heng NIAN College of Electrical Engineering Zhejiang University

We investigate two different kinds of resonant current regulators for a doubly fed induction generator(DFIG) under distorted grid voltage conditions: proportional integral resonant(PIR) regulator with traditional resonant part and vector proportional integral(VPI) regulator with VPI resonant part. Based on the mathematical model of DFIG under distorted grid voltage, the transfer function and frequency response characteristics of the two current regulators are analyzed and compared. The superiority of the VPI current regulator over the PIR regulator is pointed out, and the influence of discretization methods on the performance of the resonant current regulator is studied. All the results are validated by MATLAB simulation and experiments.

关键词： Doubly fed induction generator Harmonically distorted grid voltage Resonant current regulator Vector PI current regulator Diseretization method

An Adaptive Mesh Refinement Strategy for Immersed Boundary/Interface Methods

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Communications in Computational Physics 2012年第7期12卷 515-527页

作者： Zhilin Li peng song Center for Research in Scientific Computation&Department of Mathematics North Carolina State UniversityRaleighNC 27695USA Nanjing Normal University China Operations Research Program North Carolina StateUniversityRaleighNC 27695USA

An adaptive mesh refinement strategy is proposed in this paper for the Immersed Boundary and Immersed Interface methods for two-dimensional elliptic interface problems involving singular *** interface is represented by the zero level set of a Lipschitz functionϕ(x,y).Our adaptive mesh refinement is done within a small tube of|ϕ(x,y)|δwith finer Cartesian *** discrete linear system of equations is solved by a multigrid *** AMR methods could obtain solutions with accuracy that is similar to those on a uniform fine grid by distributing the mesh more economically,therefore,reduce the size of the linear system of the *** examples presented show the efficiency of the grid refinement strategy.

关键词： Adaptive mesh refinement immersed boundary method immersed interface method elliptic interface problem Cartesian grid method level set representation singular sources