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Crowdsourcing aggregation with deep Bayesian learning

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Science China(Information Sciences) 2021年第3期64卷 46-56页

作者： Shao-Yuan LI sheng-jun HUANG Songcan CHEN College of Computer Science and Technology College of Artificial IntelligenceNanjing University of Aeronautics and Astronautics State Key Laboratory for Novel Software Technology Nanjing University

In this study, we consider a crowdsourcing classification problem in which labeling information from crowds is aggregated to infer latent true labels. We propose a fully Bayesian deep generative crowdsourcing model(Bayes DGC), which combines the strength of deep neural networks(DNNs) on automatic representation learning and the interpretable probabilistic structure encoding of probabilistic graphical models. The model comprises a DNN classifier as a prior for the true labels and a probabilistic model for the annotation generation process. The DNN classifier and annotation generation process share the latent true label variables. To address the inference challenge, we developed a natural-gradient stochastic variational inference, which combines variational message passing for conjugate parameters and stochastic gradient descent for DNN and learns the distribution of latent true labels and workers’ confusion matrix via end-to-end training. We illustrated the effectiveness of the proposed model using empirical results on 22 real-world datasets.

关键词： crowdsourcing classification fully Bayesian deep generative models natural gradient stochastic variational inference

Hierarchical porous carbon derived from animal bone as matric to encapsulated selenium for high performance Li-Se battery

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Rare Metals 2017年第5期36卷 434-441页

作者： Li-sheng Xie sheng-Xue Yu Hui-jun Yang jun Yang Jian-Lan Ni Jiu-Lin Wang Shanghai Electrochemical Energy Devices Research Center Department of Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China College of Environment and Chemistry Engineering Yanshan UniversityQinhuangdao 066004China Shanghai Using Yuan Environmental Engineering Co. LtdShanghai 201801China

Animal bone was employed as raw material to prepare hierarchical porous carbon by KOH activation. Rare metal selenium（Se） was encapsulated into hierarchical porous carbon successfully for the cathode material of Li–Se battery, achieving the transformation of waste into energy,protecting environment and reducing the spread of the disease. Animal bone porous carbon（ABPC） acquires a specific surface area of 1244.7903 m^2·g^-1 and a pore volume of 0.594184 cm^3·g^-1. The composite Se/ABPC with 51 wt%Se was tested as a novel cathode for Li–Se batteries. The results show that Se/ABPC exhibits high specific capacity,good cycling stability and current-rate performance; at 0.1C,the composite Se/ABPC delivers a high reversible capacity of 705 mAh·g^-1 in the second cycle and 591 mAh·g^-1 after 98 cycles. Even at the current density of 2.0C, it can still maintain at a reversible capacity of 485 mAh·g^-1. The excellent electrochemical properties benefit from the high electron conductivity and the carbon with unique hierarchical porous structure. ABPC can be a promising carbon matrix for Li–Se batteries.

关键词： Se/ABPC Animal bones High rate capability Li–Se battery Hierarchical porous structure

Multi-label active learning by model guided distribution matching

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Frontiers of Computer Science 2016年第5期10卷 845-855页

作者： Nengneng GAO sheng-jun HUANG Songcan CHEN College of Computer Science and Technology Nanjing University of Aeronautics and AstronauticsCollaborative Innovation Center of Novel Software Technology and Industrialization Nanjing 211106 China

Multi-label learning is an effective framework for learning with objects that have multiple semantic labels, and has been successfully applied into many real-world tasks, In contrast with traditional single-label learning, the cost of la- beling a multi-label example is rather high, thus it becomes an important task to train an effective multi-label learning model with as few labeled examples as possible. Active learning, which actively selects the most valuable data to query their labels, is the most important approach to reduce labeling cost. In this paper, we propose a novel approach MADM for batch mode multi-label active learning. On one hand, MADM exploits representativeness and diversity in both the feature and label space by matching the distribution between labeled and unlabeled data. On the other hand, it tends to query predicted positive instances, which are expected to be more informative than negative ones. Experiments on benchmark datasets demonstrate that the proposed approach can reduce the labeling cost significantly.

关键词： multi-label learning batch mode active learning distribution matching

Dendritic and spherical crystal reinforced metallic glass matrix composites

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International Journal of Minerals,Metallurgy and Materials 2013年第4期20卷 386-392页

作者： jun-wei Qiao Yong Zhang Hui-jun Yang sheng-bo Sang Laboratory of Applied Physics and Mechanics of Advanced Materials College of Materials Science and Engineering Taiyuan University of Technology Key Laboratory of Interface Science and Engineering in Advanced Materials (Ministry of Education) Taiyuan University of Technology State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing MicroNano System Research Center Taiyuan University of Technology

Zr-based bulk metallic glass matrix composites （BMGMCs） with a composition of Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4- Be10.0 （at%） were fabricated by an innovative process, i.e., semisolid processing plus Bridgman solidification. Different morphologies, distributions, and volume fractions of the crystalline phases can be achieved by tailoring the withdrawal velocity. The largest fi-acture strain of Zr60.0Ti14.7Nb5.3Cu5.6Ni4.4Be10.0 （at%） composites with the withdrawal velocity of 1.0 mm/s was found to be 16.7%. The mechanism of plasticity improvement is mainly attributed to the interpenetrated structure of the crystalline phase, which greatly confines the rapid propagation of shear bands.

关键词： metallic glass composite materials mechanical properties plastic deformation

AMaximum-Principle-Preserving Finite Volume Scheme for Diffusion Problems on Distorted Meshes

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Advances in Applied Mathematics and Mechanics 2023年第4期15卷 1076-1108页

作者： Dan Wu junliang lv Lei Lin Zhiqiang sheng School of Mathematics Jilin UniversityChangchunJilin 130012China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijingChina

In this paper,we propose an approach for constructing conservative and maximum-principle-preserving finite volume schemes by using the method of undetermined coefficients,which depend nonlinearly on the linear non-conservative onesided *** order to facilitate the derivation of expressions of these undetermined coefficients,we explicitly provide a simple constriction condition with a scaling *** constriction conditions can ensure the final schemes are exact for linear solution problems and may induce various schemes by choosing different values for the *** particular,when this parameter is taken to be 0,the nonlinear terms in our scheme degenerate to a harmonic average combination of the discrete linear fluxes,which has often been used in a variety of maximum-principle-preserving finite volume *** our method of determining the coefficients of the nonlinear terms is more *** addition,we prove the convergence of the proposed schemes by using a compactness *** results demonstrate that our schemes can preserve the conservation property,satisfy the discrete maximum principle,possess a second-order accuracy,be exact for linear solution problems,and be available for anisotropic problems on distorted meshes.

关键词： Finite volume scheme maximum-principle-preserving scheme conservative flux

Curing kinetics and plugging mechanism of high strength curable resin plugging material

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Petroleum Science 2024年第5期21卷 3446-3463页

作者： Jing-Bin Yang Ying-Rui Bai Jin-sheng Sun Kai-He lv School of Petroleum Engineering China University of Petroleum(East China)Qingdao266580ShandongChina CNPC Engineering Technology R&D Company Limited Beijing102206China

Lost circulation, a recurring peril during drilling operations, entails substantial loss of drilling fluid and dire consequences upon its infiltration into the formation. As drilling depth escalates, the formation temperature and pressure intensify, imposing exacting demands on plug materials. In this study, a kind of controllable curing resin with dense cross-network structure was prepared by the method of solution stepwise ring-opening polymerization. The resin plugging material investigated in this study is a continuous phase material that offers effortless injection, robust filling capabilities, exceptional retention, and underground curing or crosslinking with high strength. Its versatility is not constrained by fracture-cavity lose channels, making it suitable for fulfilling the essential needs of various fracture-cavity combinations when plugging fracture-cavity carbonate rocks. Notably, the curing duration can be fine-tuned within the span of 3-7 h, catering to the plugging of drilling fluid losing of diverse fracture dimensions. Experimental scrutiny encompassed the rheological properties and curing behavior of the resin plugging system, unraveling the intricacies of the curing process and establishing a cogent kinetic model. The experimental results show that the urea-formaldehyde resin plugging material has a tight chain or network structure. When the concentration of the urea-formaldehyde resin plugging system solution remains below 30%, the viscosity clocks in at a meager 10 mPa·s. Optimum curing transpires at 60℃, showcasing impressive resilience to saline conditions. Remarkably, when immersed in a composite saltwater environment containing 50000 mg/L NaCl and 100000 mg/L CaCl_(2), the urea-formaldehyde resin consolidates into an even more compact network structure, culminating in an outstanding compressive strength of 41.5 MPa. Through resolving the correlation between conversion and the apparent activation energy of the non-isothermal DSC curing reac

关键词： Urea-formaldehyde resin Rheological property Curing property Curing kinetics Plugging mechanism

IMPROVEMENT OF SANDY SOIL WITH WATER-CONSERVING MEMBRANE AND ITS EFFECT ON CROP GROWTH

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Chinese Geographical Science 2005年第1期15卷 64-69页

作者： LIXiu-jun CUIXiang-hao LIQu-sheng Northeast Institute of Geogrophy and Agricultural Ecology Chinese Academy of SciencesChangchun 130012P.R.China Chemistry Department Jilin UniversityChangchun 130023P.R.China

Water-conserving membrane is a new material of improving sandy soil. It is based on the rule that a compound with organic and inorganic components can produce colloid after its integrating with Ca2+ in soil. The water-conserving membrane will obstruct capillary and increase viscidity of sandy soil, so as to decrease leakage and evaporation in sandy soil. The water-conserving membrane contains polyacrylic acid (PAA) and bentonite. When PAA concentration and pH of solution are different, water-conserving membrane can be made in different depth of soil. This experiment shows that the solution with 0.2% PAA does not harm and poison the crops, on the contrary, promotes crop germination. The solution with 0.2% or 0.4% PAA can accelerate corn growth. Accordingly, different crops need the application of the different PAA concentrations in the cultivation. Therefore, on the basis of different vadose coefficient in sandy soil, the solution with different PAA concentration can improve sandy soil and increase its water-conserving competence very well. The solution can be used to improve sandy soil and control desert enlargement in arid, semi-arid and semi-humid areas.

关键词： water-conserving membrane water-conserving capability germination rate crops

Toward the most versatile fluorophore: Direct functionalization of BODIPY dyes via regioselective C–H bond activation

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Chinese Chemical Letters 2019年第10期30卷 1825-1833页

作者： Wanle sheng Fan lv Bing Tang Erhong Hao Lijuan Jiao The Key Laboratory of Functional Molecular Solids Ministry of EducationSchool of Chemistry and Materials ScienceAnhui Normal UniversityWuhu241002China Department of Chemistry Bengbu Medical CollegeBengbu 233030China

Fluorescent dyes are heavily sought for their potentials applications in bioimaging, sensing, theranostic,and optoelectronic materials. Among them, BODIPY dyes are privileged fluorophores that are now widely used in highly diverse research fields. The increasing success of BODIPY dyes is closely associated with their excellent and tunable photophysical properties due to their rich functionalization ***, growing research efforts have been devoted to the direct functionalization of the BODIPY core,because it allows the facile installation of desired functional groups in a single atom economical step. The challenges of this direct C-H derivation come from the difficulties in finding suitable functionalization agents and proper control of the regioselectivity of the functionalization. The aim of this work is to provide an overview of BODIPY dyes and a summarization of the different synthetic methodologies reported for direct C–H functionalization of the BODIPY framework.

关键词： Dyes Pigments BODIPY C-H activation Radical substitution Oxidative nucleophilic substitution

Study on effect of segments erection tolerance and wedge-shaped segment on segment ring in shield tunnel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第11期7卷 1864-1869页

作者： CHEN jun-sheng MO Hai-hong Department of Civil Engineering South China University of Technology Guangzhou 510640 China

Deformation and dislocations of segments of shield tunnel in construction stage have apparent effect on tunnel structure stress and even cause local cracks and breakage in tunnel. 3D finite element method was used to analyze two segment ring models under uniform injected pressure: (1) segment ring without wedge-shaped segment, which has 16 types of preinstall erection tolerance; (2) segment ring with wedge-shaped segment, which has no preinstall erection tolerance. The analysis results indicate that different erection tolerances can cause irregular deformation in segment ring under uniform injected pressure, and that the tolerance values are enlarged further. Wedge-shaped segment apparently affects the overall deformation of segment ring without erection tolerances. The uniform injected pressure can cause deformation of ring with wedge-shaped segment irregular, and dislocations also appear in this situation. The stress of segment with erection tolerances is much larger than that of segment without erection tolerances. Enlarging the central angle of wedge-shaped segment can make the irregular deformation and dis- locations of segments smaller. The analysis results also provide basis for erection tolerance control and improvement of segment constitution.

关键词： Shield tunnel Segment Erection tolerance 3D finite element analysis