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arXiv 2021年

作者： Lei, Xinyi Chen, Zhicheng Li, Hui Key Lab of Intelligent Disaster Mitigation of the Ministry of Industry and Information Technology Harbin Institute of Technology Harbin150090 China Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education Harbin Institute of Technology Harbin150090 China School of Civil Engineering Harbin Institute of Technology Harbin150090 China

Distributional data analysis, concerned with statistical analysis and modeling for data objects consisting of random probability density functions (PDFs) in the framework of functional data analysis (FDA), has received considerable interest in recent years. However, many important aspects remain unexplored, such as outlier detection and robustness. Existing functional outlier detection methods are mainly used for ordinary functional data and usually perform poorly when applied to PDFs. To fill this gap, this study focuses on PDF-valued outlier detection, as well as its application in robust distributional regression. Similar to ordinary functional data, detecting the shape outlier masked by the "curve net’’ formed by the bulk of the PDFs is the major challenge in PDF-outlier detection. To this end, we propose a tree-structured transformation system for feature extraction as well as converting the shape outliers to easily detectable magnitude outliers, relevant outlier detectors are designed for the specific transformed data. A multiple detection strategy is also proposed to account for detection uncertainties and to combine different detectors to form a more reliable detection tool. Moreover, we propose a distributional-regression-based approach for detecting the abnormal associations of PDF-valued two-tuples. As a specific application, the proposed outlier detection methods are applied to robustify a distribution-to-distribution regression method, and we develop a robust estimator for the regression operator by downweighting the detected outliers. The proposed methods are validated and evaluated by extensive simulation studies or real data applications. Relevant comparative studies demonstrate the superiority of the developed outlier detection method with other competitors in distributional outlier detection. © 2021, CC BY.

关键词： Statistics

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DAMAGE identification with fusion of estimates from covariance of IRF in different frequency bands

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2019年 134卷 106327-000页

作者： Li, X. Y. Ye, X. Q. Law, S. S. Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Guangdong Peoples R China Chongqing Univ Sch Civil Engn Chongqing 400044 Peoples R China

Structural health monitoring is becoming more important for infrastructure worldwide in the past few decades. An accurate analytical model of the monitored engineering structure is, however, usually not available. This report presents a new non-model based damage detection method from variation of the auto (cross)-covariance of impulse response function within selected frequency bandwidths of responses obtained from the intact and damaged structural states. The covariance is computed via the wavelet packet of the responses. Bayesian fusion is applied to all the damage probability vectors obtained from the covariance under different excitations and different measurement noise. A seven-storey steel frame structure with scenarios of both single and multiple damages and complete or incomplete measurements is numerically analyzed. A similar frame was later test in the laboratory with hammer excitation. The sensors nearest to the local damages exhibit the biggest damage probability. Both numerical and experimental results show that the proposed method is effective and promising for damage detection of practical engineering structures. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Damage identification Wavelet packet energy Covariance Bayesian fusion Acceleration

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Rainformer: Features Extraction Balanced Network for Radar-Based Precipitation Nowcasting

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IEEE GEOSCIENCE AND REMOTE SENSING LETTERS 2022年 19卷 1页

作者： Bai, Cong Sun, Feng Zhang, Jinglin Song, Yi Chen, Shengyong Zhejiang Univ Technol Coll Comp Sci & Technol Hangzhou 310023 Peoples R China Nanjing Univ Informat Sci & Technol Key Lab Meteorol Disaster Minist Educ Nanjing 211544 Peoples R China Nanjing Univ Informat Sci & Technol Collaborat Innovat Ctr Forecast & Evaluat Meteoro Nanjing 211544 Peoples R China Shandong Univ Sch Control Sci & Engn Jinan 250061 Peoples R China Piesat Informat Technol Co Ltd Beijing 100195 Peoples R China Tianjin Univ Technol Coll Comp Sci & Engn Tianjin 210044 Peoples R China

Precipitation nowcasting is one of the fundamental challenges in natural hazard research. High-intensity rainfall, especially the rainstorm, will lead to the enormous loss of people's property. Existing methods usually utilize convolution operation to extract rainfall features and increase the network depth to expand the receptive field to obtain fake global features. Although this scheme is simple, only local rainfall features can be extracted leading to insensitivity to high-intensity rainfall. This letter proposes a novel precipitation nowcasting framework named Rainformer, in which, two practical components are proposed: the global features extraction unit and the gate fusion unit (GFU). The former provides robust global features learning ability depending on the window-based multi-head self-attention (W-MSA) mechanism, while the latter provides a balanced fusion of local and global features. Rainformer has a simple yet efficient architecture and significantly improves the accuracy of rainfall prediction, especially on high-intensity rainfall. It offers a potential solution for real-world applications. The experimental results show that Rainformer outperforms seven state of the arts methods on the benchmark database and provides more insights into the high-intensity rainfall prediction task.

关键词： Feature extraction Decoding Logic gates Meteorological radar Merging Fuses Data mining Feature fusion global feature high-intensity rainfall local feature precipitation nowcasting

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Dynamic Response of Asymmetric and Nonlinear Packaging System under Random Excitation

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SHOCK AND VIBRATION 2020年第1期2020卷

作者： Yang, Song-Ping Wang, Zhi-Wei Jinan Univ Packaging Engn Inst Zhuhai 519070 Peoples R China Jinan Univ Key Lab Prod Packaging & Logist Guangdong Higher Zhuhai 519070 Peoples R China Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

This paper focuses on the dynamic response of three asymmetric and nonlinear packaging systems (ANPSs) of practical transport package under random excitation. Next to presenting the displacement probability density functions (PDFs) of ANPSs derived through FPK equations, the influences of the excitation grades and the characteristic parameters (such as the damping, the nonlinear stiffness, and the strain) of packaging cushion materials on the response are discussed in detail. Then, the generalized PDFs of the response peaks are defined and examined by three common distributions. The investigation shows that "inverse excitation cushion factors" (IECFs) have a significance on effecting the displacement PDFs approaching different distributions. Most PDFs of the unilateral response peaks approach Rayleigh distributions and present non-Gaussian characters. The present methods are verified through the validation numerical solutions. Furthermore, the application of the scheme for fatigue damage evaluation of the transport package is carried out.

关键词： Probability density function

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Nonlinear dynamic response and global stability of an air compressor vibration system

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JOURNAL OF LOW FREQUENCY NOISE VIBRATION AND ACTIVE control 2019年第3-4期38卷 1081-1095页

作者： Li, Yuanping Wang, Xuemin Chen, Siyu Lu, Hongbing Jinan Univ Minist Educ Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China Jinan Univ Coliege Mech & Construct Engn Guangzhou Guangdong Peoples R China Univ Texas Dallas Dept Mech Engn Richardson TX 75083 USA Cent S Univ State Key Lab High Performance Complex Mfg Changsha Hunan Peoples R China

This study proposes a strategy for the vibration isolation mounting of an air compressor to attenuate the vibration near the primary resonance region by using a system with dynamic negative stiffness. The vibration system is modelled as a parametric pendulum system. The nonlinear dynamic responses, including the global stability of the air compressor vibration system, are investigated analytically. The efficiency of the proposed vibration isolation strategy is numerically demonstrated over the original device. To analyse the bifurcation of the nonlinear response of the pendulum system, the phase portrait, bifurcation diagram and maximum Lyapunov exponent of the pendulum system are obtained numerically. Furthermore, the Floquet multiplier level is obtained by solving the perturbation equation numerically and can be used to determine the global stability of the air compressor vibration system.

关键词： Compressor parametric pendulum system bifurcation chaos

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Full-range mechanical behavior study of FRP-to-concrete interface for pull-pull bonded joints

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COMPOSITES PART B-engineering 2019年 164卷 333-344页

作者： Liu, Sanxing Yuan, Hong Wu, Jiayu Jinan Univ Inst Appl Mech MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Jiaying Univ Sch Civil Engn Meizhou 514021 Peoples R China Southern Univ Sci & Technol Dept Ocean Sci & Engn Shenzhen 518055 Peoples R China

External bonding of fiber reinforced polymer (FRP) has become a popular technique for strengthening concrete structures all over the world. The mechanical performance of the interface between FRP and concrete is one of the key factors affecting the behavior of the strengthened structure. The debonding behavior of FRP-to-concrete interface is related to specific bonded joint. Compared with the pull-push bonded joint, there are few studies revealing the interface mechanical behavior of pull-pull bonded joint so far, and in-depth theoretical study is not profound enough either. This paper presents an analytical solution for the debonding process in such an FRP-toconcrete bonded joint in single-shear model. Base on the realistic bi-linear local bond-slip law, two critical lengths are obtained, and the interface debonding failure follows different regimes. Closed form expressions for the interfacial relative slip, shear stress distribution, normal stress in the FRP plate and the load-displacement response at the loaded end are derived for different loading stages, whose accuracy is verified by finite element numerical simulation. While the solution is developed with particular reference to FRP-to-concrete bonded joints, it can be equally applicable to similar bonded joints made of other materials (e.g. FRP-to-steel).

关键词： Fiber reinforced polymer FRP-to-concrete interface Bonded joint Shear failure Nonlinear fracture mechanics Analytical solution

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A novel method for comfort assessment in a supine sleep position using three-dimensional scanning technology

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INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS 2018年 67卷 104-113页

作者： Wu, Jiayu Yuan, Hong Li, Xin Jinan Univ Inst Appl Mech MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Mechanical interaction behavior between human body and mattress is one of the crucial physical factors affecting the sleep comfort and quality. This paper proposes a novel method for sleep (dis)comfort level assessment in a supine posture without interfering with sleep in an attempt to improve mattress design. Three-dimensional (3D) back surface model is constructed by scanning human body in an upright standing position. Based on the mechanical property of mattress and body pressure distribution measured by Tactilus system, finite element (FE) models are established to numerically calculate mattress upper surface indentation. Finally, Pearson correlation coefficient similarity measure is used to evaluate sleep (dis)comfort by compared back surface with mattress upper surface indentation. The experimental process is validated with two distinct types of mattress, namely palm fiber mattress and latex foam/palm fiber mattress. Results show that all the participants feel more comfortable when lying on latex foam/palm fiber mattress, which are in excellent agreement with the results obtained by body pressure distribution and spinal alignment.

关键词： Sleep comfort Body pressure 3D body scanning Similarity measure Finite element analysis Back surface

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Nonlinear damage detection using linear ARMA models with classification algorithms

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SMART STRUCTURES AND SYSTEMS 2020年第1期26卷 23-33页

作者： Chen, Liujie Yu, Ling Fu, Jiyang Ng, Ching-Tai Guangzhou Univ Sch Civil Engn Guangzhou Higher Educ Mega Ctr 230 Wai Huan Xi Rd Guangzhou Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn 601 West Huangpu Ave Guangzhou Peoples R China Guangzhou Higher Educ Mega Ctr Guangzhou Univ Tamkang Univ Joint Res Ctr Engn St 230 Wai Huan Xi Rd Guangzhou Peoples R China Univ Adelaide Sch Civil Environm & Min Engn North Terrace Adelaide SA 5005 Australia

Majority of the damage in engineering structures is nonlinear. Damage sensitive features (DSFs) extracted by traditional methods from linear time series models cannot effectively handle nonlinearity induced by structural damage. A new DSF is proposed based on vector space cosine similarity (VSCS), which combines K-means cluster analysis and Bayesian discrimination to detect nonlinear structural damage. A reference autoregressive moving average (ARMA) model is built based on measured acceleration data. This study first considers an existing DSF, residual standard deviation (RSD). The DSF is further advanced using the VSCS, and then the advanced VSCS is classified using K-means cluster analysis and Bayes discriminant analysis, respectively. The performance of the proposed approach is then verified using experimental data from a three-story shear building structure, and compared with the results of existing RSD. It is demonstrated that combining the linear ARMA model and the advanced VSCS, with cluster analysis and Bayes discriminant analysis, respectively, is an effective approach for detection of nonlinear damage. This approach improves the reliability and accuracy of the nonlinear damage detection using the linear model and significantly reduces the computational cost. The results indicate that the proposed approach is potential to be a promising damage detection technique.

关键词： nonlinear damage detection time series analysis linear autoregressive moving average model vector space cosine similarity classification algorithms

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A Digital Analysis of the "Digitally-Derived Geometric Design" of the Front Wall of St. Paul's Church in Macao-A Study on the Architecture and City of Macao, No. 1-

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JOURNAL OF ASIAN ARCHITECTURE AND BUILDING engineering 2018年第2期17卷 159-165页

作者： Tang, Jian Jinan Univ Minist Educ Peoples Republ China Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China

With reference to related historical archives and literature, this study conducted research into the history, the designer and the design dimensions of St. Paul's Church in Macao. The remaining drawing of the facade merely reflects the correlation deduction of each controlling point in its geometric drawing. Through digital analysis, this study has further obtained the "digitally-derived geometric design"relations of the five-layer elevation design drawing and number-rounding adjustment of the constructing dimensions: the application of the law of equal-partition in the horizontal direction, the application of the law of upward successive-subtraction in stratification in the vertical direction, and the complicated combination of golden-rectangle controlling designs. The latter two applications are key geometrical features of Baroque Architecture.

关键词： St. Paul's Church facade geometric drawing the law of upward successive-subtraction in stratification the golden ratio

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Lattice chain theories for dynamics of acoustic flexural phonons in nonpolar nanomaterials

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Physical Review B 2020年第14期102卷 144301-144301页

作者： Y. Kuang L. Lindsay Q. Wang L. He School of Mechanics and Construction Engineering MOE Key Laboratory of Disaster Forecast and Control in Engineering Jinan University Guangzhou 510632 China Materials Science and Technology Division Oak Ridge National Laboratory Oak Ridge Tennessee 37831 USA Department of Modern Mechanics University of Science and Technology of China Hefei 230026 China

Knowledge of lattice dynamics of acoustic flexural phonons is critically important in understanding the mechanical, electrical, and thermal properties of nanomaterials. However, the general nature of acoustic flexural phonons for the span of possible nanomaterials and the dependence of these on microscopic material properties remain unclear. Therefore, we develop general lattice chain theories to understand acoustic flexural vibrations in covalent and van der Waals lattices. The analytic theories suggest that the flexure branch has quadratic dispersion for low dimensional lattices in the long-wavelength limit, quite different from linear branches in bulk van der Waals bonded lattices like graphite. Surprisingly, interlayer van der Waals interactions in multilayer lattices do not determine the behavior of the flexural dispersion. The bonds of covalent interactions in multilayer and buckled monolayer lattices play different roles in determining the flexural dispersion with those in flat monolayer lattices, e.g., graphene. Further, based on the correspondence between microscopic and continuum dynamics, we provide a universal and effective approach to characterize the intrinsic bending rigidity of low dimensional nanomaterials using dispersion data.

关键词： Acoustic phonons Bending Mechanical properties of membranes

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