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Dropout training for SVMs with data augmentation

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Frontiers of Computer Science 2018年第4期12卷 694-713页

作者： Ning chen Jun ZHU Jianfei chen ting chen MOE Key lab of Bioinformatics Bioinformatics Division and Center for Synthetic and Systems Biology TNLIST Tsinghua University Beijing 100084 China State Key Lab of Intelligent Technology and Systems Department of Computer Science and Technology Tsinghua University Beijing 100084 China

Dropout and other feature noising schemes have shown promise in controlling over-fitting by artificially corrupting the training data. Though extensive studies have been performed for generalized linear models, little has been done for support vector machines （SVMs）, one of the most successful approaches for supervised learning. This paper presents dropout training for both linear SVMs and the nonlinear extension with latent representation learning. For linear SVMs, to deal with the intractable expectation of the non-smooth hinge loss under corrupting distributions, we develop an iteratively re-weighted least square （IRLS） algorithm by exploring data augmentation techniques. Our algorithm iteratively minimizes the expectation of a re- weighted least square problem, where the re-weights are analytically updated. For nonlinear latent SVMs, we con- sider learning one layer of latent representations in SVMs and extend the data augmentation technique in conjunction with first-order Taylor-expansion to deal with the intractable expected hinge loss and the nonlinearity of latent representa- tions. Finally, we apply the similar data augmentation ideas to develop a new IRLS algorithm for the expected logistic loss under corrupting distributions, and we further develop a non-linear extension of logistic regression by incorporating one layer of latent representations. Our algorithms offer insights on the connection and difference between the hinge loss and logistic loss in dropout training. Empirical results on several real datasets demonstrate the effectiveness of dropout training on significantly boosting the classification accuracy of both linear and nonlinear SVMs.

关键词： dropout SVMs logistic regression data aug- mentation iteratively reweighted least square

SURFACE AND INTERFACIAL GRAVITY WAVES INDUCED BY AN IMPULSIVE DISTURBANCE IN A TWO-LAYER INVISCID FLUID

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Journal of Hydrodynamics 2009年第1期21卷 26-33页

作者： LU Dong-qiang chen ting-ting Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The transient gravity waves due to an impulsive source in a two-layer fluid system are investigated analytically. The fluid is assumed to be inviscid and incompressible. The density of each of the two layers is constant. Five different boundary conditions are considered. The depth of each of the two layers is infinite or finite. The upper fluid of finite depth is covered by a rigid lid or a free surface. Based on the assumption of small-amplitude waves, a linear system is established. The integral solutions for the free-surface and interfacial waves are obtained by means of the Fourier-Laplace transform. The corresponding asymptotic representations are derived for large time with a fixed distance-to-time ratio by the Stokes and Scorer methods of stationary phase. The analytical solutions show that there are two different modes, namely the free-surface and interracial wave modes. The wave profiles observed depend on the relation between the distance-to-time ratio and the maximal group velocities and on the limiting values of the second derivatives of the frequencies as well.

关键词： impulsive disturbances imerfacial waves free surface waves stationary-phase methods

Influence of bubble-particle distance on the dynamic behaviors of a cavitation bubble near a particle

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Journal of Hydrodynamics 2023年第5期35卷 913-922页

作者： Yun Dai Hui Zhang ting chen School of Optical Information and Energy Engineering Wuhan Institute of TechnologyWuhan430205China

Cavitation and silt-erosion often co-exist, causing severe damage on fluid machinery. In this paper, the dynamic behavior of a cavitation bubble near a fixed spherical particle is numerically studied, with the focus on the influence of the stand-off distance γ on the bubble collapse morphology, micro-jet velocities and pressure on the particle. With the increase in the value of γ, the bubble profile in the collapse stage exhibits three distinct characteristics: Mushroom-shaped, pear-shaped and spherical-shaped, and the corresponding micro-jets are identified as contact jet, non-contact jet, and long-distance jet. All studied distances can be categorized into three ranges, and the typical cases in each range are demonstrated. The maximum jet velocity Vmax and the maximum pressure difference between the upper and the bottom of the particle Δpmax show the highest peak at γ = 0.9, with Vmax up to 180 m/s and Δpmax up to 10.8 MPa.

关键词： Cavitation bubble bubble-particle distance fixed particle micro-jet

The role of lipids in fermentative propionate production from the co-fermentation of lipid and food waste

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Frontiers of Environmental Science & Engineering 2023年第7期17卷 107-118页

作者： Niyou Xu ting chen Jun Yin School of Environmental Science and Engineering Zhejiang Gongshang UniversityHangzhou 310012China Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling Hangzhou 310012China

Food waste(FW)is a promising renewable low-cost biomass substrate for enhancing the economic feasibility of fermentative propionate *** lipids,a common component of food waste,can be used as a carbon source to enhance the production of volatile fatty acids(VFAs)during co-fermentation,few studies have evaluated the potential for directional propionate production from the co-fermentation of lipids and *** this study,co-fermentation experiments were conducted using different combinations of lipids and FW for VFA *** contributions of lipids and FW to propionate production,hydrolysis of substrates,and microbial composition *** were *** results revealed that lipids shifted the fermentation type of FW from butyric to propionic acid *** on the estimated propionate production kinetic parameters,the maximum propionate productivity increased significantly with an increase in lipid content,reaching 6.23 g propionate/(L·d)at a lipid content of 50%.Propionate-producing bacteria Prevotella,Veillonella,and norank f Propionibacteriaceae were enriched in the presence of lipids,and the succinate pathway was identified as a prominent fermentation route for propionate ***,the Kyoto Encyclopedia of Genes and Genomes functional annotation revealed that the expression of functional genes associated with amino acid metabolism was enhanced by the presence of ***,these findings will contribute to gaining a better understanding of targeted propionate production from FW.

关键词： Acidogenic fermentation Microbial community Volatile fatty acid Propionate Foodwaste Lipid

Glutamate receptors and glutamatergic signalling in the peripheral nerves

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Neural Regeneration Research 2020年第3期15卷 438-447页

作者： ting-Jiun chen Maria Kukley Center for Neuroscience Research Children’s Research InstituteChildren’s National Medical CentreWashingtonDCUSA Group of Neuron Glia Interaction University of TübingenTübingenGermany Research Institute of Ophthalmology Tübingen University HospitalTübingenGermany

In the peripheral nervous system,the vast majority of axons are accommodated within the fibre bundles that constitute the peripheral *** within the nerves are in close contact with myelinating glia,the Schwann cells that are ideally placed to respond to,and possibly shape,axonal *** mechanisms of intercellular communication in the peripheral nerves may involve direct contact between the cells,as well as signalling via diffusible *** glutamate has been proposed as a candidate extracellular molecule mediating the cross-talk between cells in the peripheral *** types of experimental findings support this idea:first,glutamate has been detected in the nerves and can be released upon electrical or chemical stimulation of the nerves;second,axons and Schwann cells in the peripheral nerves express glutamate ***,the studies providing direct experimental evidence that intercellular glutamatergic signalling takes place in the peripheral nerves during physiological or pathological conditions are largely ***,in the central nervous system,axons and myelinating glia are involved in glutamatergic *** signalling occurs via different mechanisms,the most intriguing of which is fast synaptic communication between axons and oligodendrocyte precursor *** receptors and/or synaptic axon-glia signalling are involved in regulation of proliferation,migration,and differentiation of oligodendrocyte precursor cells,survival of oligodendrocytes,and re-myelination of axons after *** synaptic signalling exist between axons and Schwann cells in the peripheral nerves?What is the functional role of glutamate receptors in the peripheral nerves?Is activation of glutamate receptors in the nerves beneficial or harmful during diseases?In this review,we summarise the limited information regarding glutamate release and glutamate receptors in the peripheral nerves and speculate about possible mechanisms of

关键词： AMPA receptors axons glutamate metabotropic glutamate receptors myelination nerve injury NMDA receptors peripheral nervous system PNS Schwann cells synaptic signalling

Integrable nonlocal PT-symmetric generalized so(3,R)-mKdV equations

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Communications in Theoretical Physics 2023年第12期75卷 19-24页

作者： Shou-ting chen Wen-Xiu Ma School of Mathematics and Statistics Xuzhou University of TechnologyXuzhou 221008JiangsuChina Department of Mathematics Zhejiang Normal UniversityJinhua 321004ZhejiangChina Department of Mathematics King Abdulaziz UniversityJeddah 21589Saudi Arabia Department of Mathematics and Statistics University of South FloridaTampaFL 33620-5700United States of America School of Mathematical and Statistical Sciences North-West UniversityMafikeng CampusPrivate Bag X2046Mmabatho 2735South Africa

Based on a soliton hierarchy associated with so(3,R),we construct two integrable nonlocal PT-symmetric generalized mKdV *** key step is to formulate two nonlocal reverse-spacetime similarity transformations for the involved spectral matrix,and therefore,integrable nonlocal complex and real reverse-spacetime generalized so(3,R)-mKdV equations of fifth-order are *** resulting reduced nonlocal integrable equations inherit infinitely many commuting symmetries and conservation laws.

关键词： integrable equation lax pair nonlocal reduction PT-symmetry zero curvature equation

redPATH:Reconstructing the Pseudo Development Time of Cell Lineages in Single-cell RNA-seq Data and Applications in Cancer

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Genomics, Proteomics & Bioinformatics 2021年第2期19卷 292-305页

作者： Kaikun Xie Zehua Liu Ning chen ting chen Institute for Artificial Intelligence State Key Lab of Intelligent Technology and SystemsDepartment of Computer Science and TechnologyTsinghua UniversityBeijing 100084China Tsinghua-Fuzhou Institute of Digital Technology Beijing National Research Center for Information Science and TechnologyTsinghua UniversityBeijing 100084China Center for Computational and Integrative Biology Massachusetts General HospitalHarvard Medical SchoolBostonMA 02114USA Department of Molecular Biology Massachusetts General HospitalHarvard Medical SchoolBostonMA 02114USA Broad Institute of Massachusetts Institute of Technology and Harvard CambridgeMA 02142USA

The recent advancement of single-cell RNA sequencing(scRNA-seq)technologies facilitates the study of cell lineages in developmental processes and *** this study,we developed a computational method,called redPATH,to reconstruct the pseudo developmental time of cell lineages using a consensus asymmetric Hamiltonian path ***,we developed a novel approach to visualize the trajectory development and implemented visualization methods to provide biological *** validated the performance of redPATH by segmenting different stages of cell development on multiple neural stem cell and cancer datasets,as well as other single-cell transcriptome *** particular,we identified a stem cell-like subpopulation in malignant glioma *** cells express known proliferative markers,such as GFAP,ATP1A2,IGFBPL1,and ALDOC,and remain silenced for quiescent markers such as ***,we identified MCL1 as a significant gene that regulates cell apoptosis and CSF1R for reprogramming macrophages to control tumor *** conclusion,redPATH is a comprehensive tool for analyzing scRNA-seq datasets along the pseudo developmental *** is available at https://***/tinglabs/redPATH.

关键词： Single-cell pseudotime reconstruction Consensus Hamiltonian path Cell differentiation Cell proliferation Cell development and diseases

Effects of Cover Sheets on the Nugget Growth and Fracture Behavior of Resistance Spot Welded Q&P980 Steel Joints

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 360-373页

作者： Zhanxiang Ling ting chen Liang Kong Min Wang Shanghai Key Laboratory of Materials Laser Processing and Modifcation Shanghai Jiao Tong UniversityShanghai 200240China

The resistance spot weldability of galvanized ultra-high-strength steels is not satisfed,the joints are prone to interfacial fracture and the weldable current range is *** solve the problems,a novel method called resistance spot welding with double-sided cover sheets was introduced to weld a galvanized Q&P980 steel with the thickness of 1.2 *** thin SPCC mild steel sheets were chosen as cover sheets and were placed symmetrically at both sides between the Q&P980 steels and the electrodes,then the RSW process was carried *** with the traditional RSW method,the joints obtained by using the novel method achieved larger tensile shear strength and energy absorption,which increased by 26.9%and 52.6%,*** increasing the welding current,the failure mode transferred from interfacial fracture to nugget pull-out fracture or base metal tearing *** contrast,the joints always showed interfacial fracture without cover *** improvement of the joint performance was mainly attributed to the enlargement of the *** the help of fnite element simulation,it was found that the cover sheets helped increase the contact area and reduced the current density during welding,which postponed the expulsion,and a larger area could be evenly *** application of the novel method can be easily extended to the resistance spot welding of other ultra-high-strength steels with various thicknesses.

关键词： Resistance spot welding Q&P980 steel Cover sheet Mechanical property

An efficient and authenticated key establishment scheme based on fog computing for healthcare system

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Frontiers of Computer Science 2022年第4期16卷 173-184页

作者： Xinghua Li ting chen Qingfeng cheng Jianfeng Ma School of Cyber Engineering Xidian UniversityXi’an710071China

Because of its closeness to users,fog computing responds faster than cloud ***,it has been deployed to various applications,such as healthcare ***,to ensure the secure communication of the fog-based healthcare system,Jia et *** an authenticated key agreement ***,in view of the high computation cost existing in Jia et al.’s scheme,Ma et *** an efficient one using elliptic curve *** this paper,we observe that both the two schemes may potentially risk ephemeral key compromise attacks and need ***,to overcome this potential risk,we propose a new authenticated scheme based on Jia et al.’s scheme using elliptic curve computational Diffie-Hellman hypothesis and hash ***,we provide provable security under the adopted adversarial model and ProVerif simulation,and also analyze the performance in terms of computation and communication costs by *** analysis results show that the improved scheme resists the common attacks,reduces computation overhead,and has a certain significance.

关键词： authenticated key establishment ephemeral key compromise attack fog-driven healthcare system elliptic curve cryptography provable security ProVerif simulation