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Two-Stage Point Cloud Super Resolution with Local Interpolation and Readjustment via Outer-Product Neural Network

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Journal of Systems Science & Complexity 2021年第1期34卷 68-82页

作者： WANG Guangyu XU Gang wu qing wu Xundong School of Computer Science and Technology Hangzhou Dianzi UniversityHangzhou 310018China Key Laboratory of Complex Systems Modeling and Simulation Ministry of EducationHangzhou 310018China

This paper proposes a two-stage point cloud super resolution framework that combines local interpolation and deep neural network based readjustment. For the first stage, the authors apply a local interpolation method to increase the density and uniformity of the target point cloud. For the second stage, the authors employ an outer-product neural network to readjust the position of points that are inserted at the first stage. Comparison examples are given to demonstrate that the proposed framework achieves a better accuracy than existing state-of-art approaches, such as PU-Net, Point Net and DGCNN(Source code is available at https://***/qwerty1319/PC-SR).

关键词： Neural network outer-product network point cloud super resolution

Microstructural evolution of a steam-turbine rotor subjected to a water-quenching process: numerical simulation and experimental verification

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Advances in Manufacturing 2019年第1期7卷 84-104页

作者： Chuan wu qing-Ling Meng National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die & Mould College of Mechanical Engineering Tianjin University of Technology and Education Tianjin 300222 People's Republic of China College of Civil Engineering Tianjin University Tianjin 300072 People's Republic of China

Cr-Ni-Mo-V steam-turbine rotors have been widely used as key components in power plants. In this study, a coupled thermomechano-metallurgical model was proposed to simulate the phase transformation and transformation-induced plasticity (TRIP) of a 30Cr2Ni4MoV steam-turbine rotor during a water-quenching process, which was solved using a user defined material mechanical behavior (UMAT) subroutine in ABAQUS. The thermal dilation, heat generation from plastic work, transformation latent heat, phase transformation kinetics, and TRIP were considered in the model. The thermomechanical portion of the model was used to predict the evolution of temperature, strain, and residual stress in the rotor. The phase transformation that occurred during the quenching process was considered. Constitutive models of phase transformations (austenite to pearlite, austenite to bainite, and austenite to martensite) and TRIP were developed. Experimental data were adopted and compared with the predicted results to verify the accuracy of the model. This demonstrates that the model is reliable and accurate. Then, the model was utilized to predict the temperature variation, dimensional change, minimum austenitization time, residual stress, TRIP, and volume fractions of each phase. It is concluded that this model can be a useful computational tool in the design of heat-treatment routines of steam-turbine rotors.

关键词： Thermomechano-metallurgical model user defined material mechanical behavior (UMAT) subroutine Microstructural evolution Transformation-induced plasticity (TRIP)- Residual stress

On the Existence and Uniqueness of Solutions to Stochastic Differential Equations Driven by G-Brownian Motion with Integral-Lipschitz Coefficients

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Acta Mathematicae Applicatae Sinica 2014年第3期30卷 589-610页

作者： xue-peng BAI Yi-qing LIN Institut de Recherche Mathématique de Rennes Université de Rennes1 School of Mathematics Shandong University Institut de Recherche Mathématique de Rennes Université de Rennes

In this paper, we study the existence and uniqueness of solutions to stochastic differential equations driven by G-Brownian motion （GSDEs） with integral-Lipschitz coefficients.

关键词： G-Brownian motion G-expectation G-stochastic differential equations G-backward stochastic differential equations integral-Lipschitz condition

Study of pollutant transport in depth-averaged flows using random walk method

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Journal of Hydrodynamics 2019年第2期31卷 303-316页

作者： xue-fei wu Dongfang Liang School of Environment and Resource Southwest University of Science and TechnologyMianyang 621010China Department of Engineering University of CambridgeCambridgeUK

The random walk particle tracking(RWPT)method is compared with the Eulerian methods in investigating pollutant transport in depth-averaged *** a typical representative of the Eulerian model with high performance,the MacCormack scheme with Total Variation Diminishing modification(TVD-Mac)is selected for *** concentration is simulated in four case ***,both numerical models have been tested in two idealized cases and compared against analytical *** dissipation is observed for TVD-Mac model where the concentration changes abruptly,especially under the circumstances of low resolution and misalignment between the flow direction and grid *** the contrary,simulations by the random walk model achieve higher accuracy in both cases and are free of fictitious oscillations in the vicinity of sharp concentration ***,the solute oscillation along a one-dimensional hypothetical tidal estuary is simulated,with the RWPT accurately con serving mass and suffering less rm merical diffusion compared with the Eulerian ***,the process of pollutant transport in a Yangzte River reach is predicted by the *** longitudinal dispersion coefficient DL is calculated *** is compared favorably with the theoretical/empirical formulae,indicating the validity of the RWPT in solving complex natural problems.

关键词： Pollutant transport depth-averaged flows random walk particle tracking TVD-MacCormack

Non-homogeneous Tb Theorem for Bi-parameter g-function

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Acta Mathematica Sinica,English Series 2018年第9期34卷 1445-1459页

作者： Ming Ming CAO qing Ying xue School of Mathematical Sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education

The main result of this paper is a bi-parameter Tb theorem for Littlewood-Paley g-function, where b is a tensor product of two pseudo-accretive function. Instead of the doubling measure, we work with a product measure μ = μn × μm, where the measures μn and μm are only assumed to be upper doubling. The main techniques of the proof include a bi-parameter b-adapted Haar function decomposition and an averaging identity over good double Whitney regions. Moreover, the non-homogeneous analysis and probabilistic methods are used again.

关键词： Bi-parameter square function probabilistic method b-adapted Haar functions

Marine spatio-temporal process semantics and its applications-taking the El Nio Southern Oscilation process and Chinese rainfall anomaly as an example

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Acta Oceanologica Sinica 2012年第2期31卷 16-24页

作者： xue Cunjin DONG qing XIE Jiong Key Laboratory of Digital Earth Science Center for Earth Observation and Digital EarthChinese Academy of SciencesBeijing 100094China State Key Laboratory of Resource and Environment Information System Institute of GeographicalScience and Natural ResourcesChinese Academy of SciencesBeijing 100101China

Spatio-temporal semantics based on ＂object views＂ or ＂event views＂ has few abilities to represent and model the continuity and gradual oceanic phenomena or objects, which seriously limits the specific marine applications and knowledge discovery and data mining, so this paper proposes a hierarchical abstraction semantics with ＂marine spatio-temporal process-life span phases-evolution sequences--state units＂ and process objects included by level with ＂marine process objects--phase objects--sequence object---state objects＂ with the oceanic process characteristics into the marine process semantics. In addition, this paper designs the storage and representation of marine process objects using the backus normal forms （BNF） and abstract data type （ADT）. Base on E1 Nifio Southern Oscilation （ENSO） index and Chinese rain gauging station data, this paper also gives a case of study. The spatio-temporal analysis between ENSO process and Chinese rainfall anomalies shows that the marine spatio-temporal semantics not only can illustrate the spatial distribution of Chinese rainfall anomalies in different time scales at ENSO process, life span phases and state units, but also analyze the dynamic changes of Chinese rainfall anomalies in different life span phases or state units within ENSO evolution.

关键词： marine process semantics hierarchical abstraction and inclusion by level ENSO proc ess rainfall anomalies

Characterization of Mutations in Genes Related to Rifampicin and Isoniazid Resistance in Multidrug-resistant Mycobacterium tuberculosis Strains from Hangzhou,China

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Biomedical and Environmental Sciences 2023年第9期36卷 869-873页

作者： HUANG Yin Yan XIE Li wu Yi Fei JIA qing Jun CHENG qing Lin LI qing Chun AI Li Yun BAI xue Xin Department of TB Control and Prevention Hangzhou Center for Disease Control and PreventionHangzhou 310021ZhejiangChina

Tuberculosis(TB),caused by the Mycobacterium tuberculosis complex(MTBC),is the 13^(th)leading cause of death and the second leading cause of infectious killer after COVID-19(above HIV and AIDS),according to the World Health Organization's 2022 Global TB *** 2021,10.6 million people were diagnosed with a new episode of TB and 1.6 million people died as a result.

关键词： tuberculosis death Mycobacterium

Mixed D-vine copula-based conditional quantile model for stochastic monthly streamflow simulation

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Water Science and Engineering 2024年第1期17卷 13-20页

作者： Wen-zhuo Wang Zeng-chuan Dong Tian-yan Zhang Li Ren Lian-qing xue Teng wu College of Water Resources and Hydrology Hohai UniversityNanjing 210098China Yellow River Research Center Hohai UniversityNanjing 210098China

Copula functions have been widely used in stochastic simulation and prediction of ***,existing models are usually limited to single two-dimensional or three-dimensional copulas with the same bivariate block for all *** address this limitation,this study developed a mixed D-vine copula-based conditional quantile model that can capture temporal *** model can generate streamflow by selecting different historical streamflow variables as the conditions for different months and by exploiting the conditional quantile functions of streamflows in different months with mixed D-vine *** up-to-down sequential method,which couples the maximum weight approach with the Akaike information criteria and the maximum likelihood approach,was used to determine the structures of multivariate Dvine *** developed model was used in a case study to synthesize the monthly streamflow at the Tangnaihai hydrological station,the inflow control station of the Longyangxia Reservoir in the Yellow River *** results showed that the developed model outperformed the commonly used bivariate copula model in terms of the performance in simulating the seasonality and interannual variability of *** model provides useful information for water-related natural hazard risk assessment and integrated water resources management and utilization.

关键词： Stochastic monthly streamflow simulation Mixed D-vine copula Conditional quantile model Up-to-down sequential method Tangnaihai hydrological station

A DFT study of the CO adsorption and oxidation at ZnO surfaces and its implication for CO detection

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Chinese Chemical Letters 2020年第6期31卷 1674-1679页

作者： Zibin Ni Shenyuan Bao xue-qing Gong Key Laboratory for Advanced Materials Centre for Computational Chemistry and Research Institute of Industrial CatalysisSchool of Chemistry&Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Recently,ZnO-based gas sensors have been successfully fabricated and widely studied for their excellent sensitivity and selectivity,especially in CO ***,detailed explorations of their mechanisms are rather ***,aiming at clarifying the sensing mechanism,we carried out density functional theory(DFT)calculations to track down the CO adsorption and oxidation on the ZnO(1010)and(1120)*** calculated results show that the lattice O of ZnO(1010)is more reactive than that of ZnO(1120)for CO *** the calculated energetics and structures,the main reaction product on both surfaces can be determined to be CO2 rather than ***,the surface conductivity changes during the adsorption and reaction processes of CO were also *** both ZnO(1010)and(1120),the conductivity would increase upon CO adsorption and decrease following CO oxidation,in consistence with the reported experimental *** work can help understand the origins of ZnO-based sensors’performances and the development of novel gas sensors with higher sensitivity and selectivity.

关键词： Density functional theory ZnO Gas sensor CO oxidation Surface conductivity