检索结果-南通市图书馆

Discriminative low-rank embedding with manifold constraint for image feature extraction and classification

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2024年第5期20卷 299-306页

作者： YAN Chunman WEI Shuhong School of Physics and Electronic Engineering Northwest Normal UniversityLanzhou 730070China Engineering Research Center of Gansu Province for Intelligent Information Technology and Application Lanzhou 730070China

The robustness against noise, outliers, and corruption is a crucial issue in image feature extraction. To address this concern, this paper proposes a discriminative low-rank embedding image feature extraction algorithm. Firstly, to enhance the discriminative power of the extracted features, a discriminative term is introduced using label information, obtaining global discriminative information and learning an optimal projection matrix for data dimensionality reduction. Secondly, manifold constraints are incorporated, unifying low-rank embedding and manifold constraints into a single framework to capture the geometric structure of local manifolds while considering both local and global information. Finally, test samples are projected into a lower-dimensional space for classification. Experimental results demonstrate that the proposed method achieves classification accuracies of 95.62%, 95.22%, 86.38%, and 86.54% on the ORL, CMUPIE, AR, and COIL20 datasets, respectively, outperforming dimensionality reduction-based image feature extraction algorithms.

关键词： manifold embedding dimensionality

Experimental Investigation of Regular or Wavy Two-Phase Flow in a manifold

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2023年第1期19卷 37-50页

作者： Xiaowei Nie Lihui Ma Yiqiu Xu Dong Sun Weibo Zheng Liang Zhou Xiaodong Wang Xiaohan Zhang Weijia Dong Yunfei Li Sionpec Shengli Oilfield Company Dongying257000China Technical Inspection Center Sionpec Shengli Oilfield CompanyDongying257000China Offshore Oil Engineering Co. Ltd.Dongying257000China

An experimental study was conducted to investigate the properties of stratified regular or wavy two-phase flow in two parallel separators located after a manifold.A total of 103 experiments with various gas and liquid velocity combinations in three inlet pipes were conducted,including 77 groups of outlet pipe resistance symmetry and 26 groups of outlet pipe resistance asymmetry trials.The experimental results have revealed that when the gas-liquid flow rate is low,the degree of uneven splitting is high,and“extreme”conditions are attained.When the superficial gas velocity is greater than that established in the extreme case,the direction of the liquid-phase displacement is reversed,while that of the gas remains unchanged.Thus,the degree of gas phase bias tends to be mitigated with an increase in the gas velocity,while the uneven splitting degree of liquid approaches 10%.Finally,varying the gas-phase outlet pipe resistance is shown to effectively change the gas-liquid two-phase flow distribution.

关键词： Uneven phase distribution two-phase flow manifold asymmetric resistance

manifold learning of four-dimensional scanning transmission electron microscopy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2019年第1期5卷 1097-1104页

作者： Xin Li Ondrej E.Dyck Mark P.Oxley Andrew R.Lupini Leland McInnes John Healy Stephen Jesse Sergei V.Kalinin Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTN 37831USA Institute for Functional Imaging of Materials Oak Ridge National LaboratoryOak RidgeTN 37831USA Tutte Institute for Mathematics and Computing OttawaCanada

Four-dimensional scanning transmission electron microscopy(4D-STEM)of local atomic diffraction patterns is emerging as a powerful technique for probing intricate details of atomic structure and atomic electric fields.However,efficient processing and interpretation of large volumes of data remain challenging,especially for two-dimensional or light materials because the diffraction signal recorded on the pixelated arrays is weak.Here we employ data-driven manifold leaning approaches for straightforward visualization and exploration analysis of 4D-STEM datasets,distilling real-space neighboring effects on atomically resolved deflection patterns from single-layer graphene,with single dopant atoms,as recorded on a pixelated detector.These extracted patterns relate to both individual atom sites and sublattice structures,effectively discriminating single dopant anomalies via multimode views.We believe manifold learning analysis will accelerate physics discoveries coupled between data-rich imaging mechanisms and materials such as ferroelectric,topological spin,and van der Waals heterostructures.

关键词： manifold straight details

An investigation on application potentiality of microstructure heat sinks with different flow topological morphology

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2022年第12期65卷 2895-2909页

作者： YAO XiaoLe SHI QianLei LIU Qian QIN Le JU Xing XU Chao Key Laboratory of Power Station Energy Transfer Conversion and System of MOE North China Electric Power UniversityBeijing 102206China

Microstructure heat sinks have great potential for high heat flux cooling.In this paper,we compared microchannel(MC),micro-pin-fin(MPF),manifold microchannel(MMC),and manifold micro-pin-fin(MMPF)heat sinks to figure out the pros and cons.Fluid flow and manifold unit models are used to study thermal and hydrodynamic performance.The heat sinks with different channel/fin sizes,manifold numbers,and porosities are discussed according to the pressure drop,temperature,thermal resistance,and coefficient of performance.Results show that MMC and MMPF heat sinks are superior to MC and MPF heat sinks,and there are also differences between MMC and MMPF heat sinks.Typically,the MMPF heat sink has lower maximum temperature,temperature non-uniformity,and total thermal resistance R_(tot).In contrast,the MMC heat sink has a lower pressure drop and higher COP.For the MMPF heat sink,at the nozzle width of 6.75μm and the MPF width of 70.71μm(porosity=0.167),it achieves the lowest total thermal resistance of R_(tot)=2.97×10^(-6)K m^(2)/W.Under 10^(3)W/cm^(2)heat flux,the maximum surface temperature rise is 29.74 K,and the maximum temperature difference of the heating surface is 3.15 K.This research initially provides a clear reference on the selection of single-phase cooling microstructures for ultra-high heat flux dissipation.

关键词： heat sink topology manifold microchannel micro-pin-fin high heat flux

Evaluation of the submarine debris-flow hazard risks to planned subsea pipeline systems: a case study in the Qiongdongnan Basin, South China Sea

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2023年第5期42卷 139-153页

作者： Mingquan Huang Xuesheng Qian Jingping Xu Xuecheng Li School of Environment Harbin Institute of TechnologyHarbin 150001China Department of Ocean Science and Engineering Southern University of Science and TechnologyShenzhen 518055China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China China Offshore Fugro Geosolutions(Shenzhen)Corporation Limited Shenzhen 518067China

The ever-increasing deepwater oil and gas development in the Qiongdongnan Basin,South China Sea has initiated the need to evaluate submarine debris-flow hazard risks to seafloor infrastructures.This paper presents a case study on evaluating the debris-flow hazard risks to the planned pipeline systems in this region.We used a numerical model to perform simulations to support this quantitative evaluation.First,one relict failure interpreted across the development site was simulated.The back-analysis modeling was used to validate the applicability of the rheological parameters.Then,this model was applied to forecast the runout behaviors of future debris flows originating from the unstable upslope regions considered to be the most critical to the pipeline systems surrounding the manifolds A and B.The model results showed that the potential debris-flow hazard risks rely on the location of structures and the selection of rheological parameters.For the manifold B and connected pipeline systems,because of their remote distances away from unstable canyon flanks,the potential debris flows impose few risks.However,the pipeline systems around the manifold A are exposed to significant hazard risks from future debris flows with selected rheological parameters.These results are beneficial for the design of a more resilient pipeline route in consideration of future debris-flow hazard risks.

关键词： submarine debris flow pipeline manifold hazard evaluation route optimization Qiongdongnan Basin

Rotation errors in numerical manifold method and a correction based on large deformation theory

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2019年第5期13卷 1036-1053页

作者： Ning ZHANG Xu LI Qinghui JIANG Xingchao LIN School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong UniversityBeijing 100044China School of Civil and Architectural Engineering Wuhan UniversityWuhan 430072China State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin Beijing 100038China

Numerical manifold method (NMM) is an effective method for simulating block system, however, significant errors are found in its simulation of rotation problems. Three kinds of errors, as volume expansion, stress vibration, and attenuation of angular velocity, were observed in the original NMM. The first two kind errors are owing to the small deformation assumption and the last one is due to the numerical damping. A large deformation NMM is proposed based on large deformation theory. In this method, the governing equation is derived using Green strain, the large deformation iteration and the open-close iteration are combined, and an updating strategy is proposed. The proposed method is used to analyze block rotation, beam bending, and rock falling problems and the results prove that all three kinds of errors are eliminated in this method.

关键词： numerical manifold method rotation large deformation Green strain open-close iteration

Turbulent combustion modeling using a flamelet generated manifold approach——a validation study in Open FOAM

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2019年第8期40卷 1197-1210页

作者： Tao LI Fanfu KONG4 Baopeng XU Xiaohan WANG Guangzhou Institute of Energy Conversion Chinese Academy of Sciences Guangzhou 510640China Key Laboratory of Renewable Energy Chinese Academy of Sciences Guangzhou 510640China Guangdong Provincial Key Laboratory of New and Renewable Energy Research and Development Guangzhou 510640China Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of TechnologyDalian 116024Liaoning ProvinceChina

An OpenFOAM based turbulence combustion solver with flamelet generated manifolds (FGMs) is presented in this paper. A series of flamelets, representative for turbulent flames, are calculated first by a one-dimensional (1D) detailed chemistry solver with the consideration of both transport and stretch/curvature contributions. The flame structure is then parameterized as a function of multiple reaction control variables. A manifold, which collects the 1D flame properties, is built from the 1D flame solutions. The control variables of the mixture fraction and the progress variable are solved from the corresponding transport equations. During the calculation, the scalar variables, e.g., temperature and species concentration, are retrieved from the manifolds by interpolation. A transport equation for NO is solved to improve its prediction accuracy. To verify the ability to deal with the enthalpy loss effect, the temperature retrieved directly from the manifolds is compared with the temperature solved from a transport equation of absolute enthalpy. The resulting FGM-computational fluid dynamics (CFD) coupled code has three significant features, i.e., accurate NO prediction, the ability to treat the heat loss effect and the adoption at the turbulence level, and high quality prediction within practical industrial configurations. The proposed method is validated against the Sandia flame D, and good agreement with the experimental data is obtained.

关键词： flamelet generated manifold turbulent combustion NO prediction

Aircraft safety analysis based on differential manifold theory and bifurcation method

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2019年第2期20卷 292-299页

作者： Chi ZHOU Ying-hui LI Wu-ji ZHENG Peng-wei WU School of Aeronautics and Astronautics Engineering Air Force Engineering University

Loss of control(LOC) is considered one of the leading causes of fatal aircraft accidents worldwide. Reducing LOC is critical to improve flight safety. Although it is still vaguely defined, LOC is generally associated with a flight state that is outside the safety envelope, with nonlinear influences of aircraft dynamics and incorrect handling by the flight crew. We have studied how nonlinear factors and pilot operations contribute to LOC. In this study, the stall point and bifurcation point are confirmed using the bifurcation analysis, and the results show that the aircraft will stall when excessive elevator movement is commanded. Moreover, even though there may be an equilibrium state in one of the elevator deflections, the flight state may still be outside the flight safety envelope. When the flight state is near the edge of the flight safety envelope, the strategy to regulate the elevator deflection is super-sensitive, and a slight change in the elevator deflection may contribute to a flight state outside the safety envelope. To solve this issue, the differential manifold theory is introduced to determine the safety envelope. Examples are provided using NASA's generic transport model.

关键词： Loss of control Safety envelope Aircraft dynamic Bifurcation analysis Differential manifold theory

Image-based 3D model retrieval using manifold learning

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2018年第11期19卷 1397-1408页

作者： Pan-pan MU San-yuan ZHANG Yin ZHANG Xiu-zi YE Xiang PAN College of Computer Science and Technology Zhejiang University College of Mathematics and Information Science Wenzhou University College of Computer Science and Technology Zhejiang University of Technology

We propose a new framework for image-based three-dimensional(3D) model retrieval. We first model the query image as a Euclidean point. Then we model all projected views of a 3D model as a symmetric positive definite(SPD) matrix, which is a point on a Riemannian manifold. Thus, the image-based 3D model retrieval is reduced to a problem of Euclid-to-Riemann metric learning. To solve this heterogeneous matching problem, we map the Euclidean space and SPD Riemannian manifold to the same high-dimensional Hilbert space, thus shrinking the great gap between them. Finally, we design an optimization algorithm to learn a metric in this Hilbert space using a kernel trick. Any new image descriptors, such as the features from deep learning, can be easily embedded in our framework. Experimental results show the advantages of our approach over the state-of-the-art methods for image-based 3D model retrieval.

关键词： Model retrieval Euclidean space Riemannian manifold Hilbert space Metric learning