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Novel linear search for support vector machine parameter selection

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Journal of Zhejiang University-Science C(Computers and Electronics) 2011年第11期12卷 885-896页

作者： Hong-xia PANG Wen-de DONG zhi-hai XU Hua-jun FENG qi LI Yue-ting CHEN State Key Laboratory of Optical Instrumentation Zhejiang University Hangzhou 310027 China

Selecting the optimal parameters for support vector machine (SVM) has long been a hot research topic. Aiming for support vector classification/regression (SVC/SVR) with the radial basis function (RBF) kernel, we summarize the rough line rule of the penalty parameter and kernel width, and propose a novel linear search method to obtain these two optimal parameters. We use a direct-setting method with thresholds to set the epsilon parameter of SVR. The proposed method directly locates the right search field, which greatly saves computing time and achieves a stable, high accuracy. The method is more competitive for both SVC and SVR. It is easy to use and feasible for a new data set without any adjustments, since it requires no parameters to set.

关键词： Support vector machine (SVM) Rough line rule Parameter selection Linear search Motion prediction

Characteristics of mRNA dynamic expression related to spinal cord ischemia/reperfusion injury:a transcriptomics study

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Neural Regeneration Research 2016年第3期11卷 480-486页

作者： zhi-ping qi Peng xia Ting-ting Hou Ding-yang Li Chang-jun Zheng xiao-yu Yang The Second Hospital Jilin University

Following spinal cord ischemia/reperfusion injury,an endogenous damage system is immediately activated and participates in a cascade *** is difficult to interpret dynamic changes in these pathways,but the examination of the transcriptome may provide some *** transcriptome reflects highly dynamic genomic and genetic information and can be seen as a precursor for the *** used DNA microarrays to measure the expression levels of dynamic evolution-related m RNA after spinal cord ischemia/reperfusion injury in *** abdominal aorta was blocked with a vascular clamp for 90 minutes and underwent reperfusion for 24 and 48 *** simple ischemia group and sham group served as *** rats had regained consciousness,hindlimbs showed varying degrees of functional impairment,and gradually improved with prolonged reperfusion in spinal cord ischemia/reperfusion injury ***-eosin staining demonstrated that neuronal injury and tissue edema were most severe in the 24-hour reperfusion group,and mitigated in the 48-hour reperfusion *** were 8,242 differentially expressed m RNAs obtained by Multi-Class Dif in the simple ischemia group,24-hour and 48-hour reperfusion *** m RNA dynamic expression patterns were obtained by Serial Test *** them,five patterns were *** the No.28 pattern,all differential genes were detected in the 24-hour reperfusion group,and their expressions showed a trend in ***.11 pattern showed a decreasing trend in m RNA whereas No.40 pattern showed an increasing trend in m RNA from ischemia to 48 hours of reperfusion,and peaked at 48 *** the No.25 and No.27 patterns,differential expression appeared only in the 24-hour and 48-hour reperfusion *** the five m RNA dynamic expression patterns,No.11 and No.40 patterns could distinguish normal spinal cord from pathological ***.25 and No.27 patterns could distinguish simple ischemia from ischemia/reperfu

关键词： nerve regeneration spinal cord injury ischemia/reperfusion injury messenger RNA transcription oligonucleotide sequence microarray transcriptome c DNA sequence NADPH oxidase neural regeneration

Photometric investigation and orbital period analyses of the W UMa binaries FP Lyn, FV CVn and V354 UMa

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Research in Astronomy and Astrophysics 2019年第7期19卷 103-114页

作者： Raul Michel qi-qi xia Jesus Higuera1 Observatorio Astronomico Nacional Instituto de AstronomíaUniversidad Nacional Autońoma de MéxicoApartado Postal 877EnsenadaB.C.22830Mexico Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong UniversityWeihai 264209China

New light curves and photometric solutions of FP Lyn,FV CVn and V354 UMa are *** found that these three systems are W-subtype shallow contact *** addition,it is obvious that the light curves of FP Lyn and V354 UMa are ***,a hot spot was added on the primary star of FP Lyn and a dark spot was added on the secondary star of V354 *** the same time,we added a third light to the photometric solution of FP Lyn for the final *** obtained mass ratios and fill-out factors are q = 1.153 and f = 13.4% for FP Lyn,q = 1.075 and f = 4.6% for FV CVn,and q = 3.623 and f = 10.7% for V354 UMa *** investigations of orbital period for these three systems indicate that the periods are *** Lyn and V354 UMa were discovered to have secularly increasing components with rates of dp/dt = 4.19 ×10^-7 dyr^-1 and dp/dt = 7.70 ×10^-7 dyr^-1 respectively,which are feasibly caused by conservative mass transfer from the less massive component to the more massive *** addition,some variable components were discovered for FV CVn,including a rate of dp/dt =-1.13 ×10^-6 dyr^-1 accompanied by a cyclic oscillation with amplitude and period of 0.0069 d and 10.65 yr *** most likely explanation for the long-term decrease is angular momentum *** existence of an additional star is the most plausible explanation for the periodic variation.

关键词： stars:binaries:close stars:binaries:eclipsing stars:individual (FP Lyn, FV CVn and V354 UMa)

The Extension of a Quantized Borcherds Superalgebra by a Hopf Algebra

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Acta Mathematica Sinica,English Series 2016年第3期32卷 363-372页

作者： Li xia YE zhi xiang WU Department of Mathematics Zhejiang International Studies University School of Mathematical Sciences Zhejiang University

A two-parameter quantum group is obtained from the usual enveloping algebra by adding two commutative grouplike elements. In this paper, we generalize this procession further by adding commutative grouplike elements b（ik）, c（ik）, g（ik）, h（ik）（i ∈I, k = 1,..., mi） of a Hopf algebra H to the quantized enveloping algebra Uq（G） of a Borcherds superalgebra G defined by a symmetrizable integral Borcherds–Cartan matrix A =（aij）i,j∈I. Therefore, we define an extended Hopf superalgebra HUq（G）. We also discuss the basis and the grouplike elements of HUqG.

关键词： Borcherds superalgebra Hopf algebra quantized enveloping algebra

Quick estimation of the D_(pb) for predicting the strength of chemical bond in situ

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Chinese Chemical Letters 2013年第10期24卷 912-916页

作者： xia Du Dong-xia Zhao Zhong-zhi Yang Chemistry and Chemical Engineering Faculty Liaoning Normal University

An approximate method has been established to calculate the depth of the potential acting on an electron in a molecule at the saddle point along a chemical bond, denoted by Dpb. It is a new indicator which can be used for predicting the strength of a chemical bond. In this work, as a practical application for demonstrating this method, we calculated the Dpb of deoxyribonucleosides and ribonucleosides along all C-H and N-H chemical bonds using the method. The results are in fair agreement with those results of previously reported experimental and theoretical observations,

关键词： Bond strength Dpb Deoxyribouncleosides Ribonucleosides

Fracture characterization and permeability prediction by pore scale variables extracted from X-ray CT images of porous geomaterials

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Science China(Technological Sciences) 2020年第5期63卷 755-767页

作者： ZHAO zhi ZHOU xiao-Ping qiAN qi-Hu School of Civil Engineering Chongqing UniversityChongqing 400045China State Key Laboratory of Disaster Prevention and Mitigation of Explosion and Impact PLA University of Science and TechnologyNanjing 210014China

Pore scale variables(e.g.,porosity,grain size)are important indexes to predict the hydraulic properties of porous geomaterials.X-ray images from ten types of intact sandstones and another type of sandstone samples subjected to triaxial compression are used to investigate the permeability and fracture characteristics.A novel double threshold segmentation algorithm is proposed to segment cracks,pores and grains,and pore scale variables are defined and extracted from these X-ray CT images to study the geometric characteristics of microstructures of porous ***,novel relations among these pore scale variables for permeability prediction are established,and the evolution process of cracks is *** results indicate that the porescale permeability is prominently improved by *** addition,excellent agreements are found between the measured and the estimated pore scale variables and *** established correlations can be employed to effectively identify the hydraulic properties of porous geomaterials.

关键词： sandstones X-ray CT images pore scale variables permeability prediction cracks characterization

An SIS epidemic model with diffusion

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Applied Mathematics(A Journal of Chinese Universities) 2017年第2期32卷 127-146页

作者： XU zhi-ting CHEN Dan-xia School of Mathematical Sciences South China Normal UniversityGuangzhou 510631China.

The aim of this paper is to study the diffusion. We first study the well-posedness of the dynamics of an SIS epidemic model with model. And then, by using linearization method and constructing suitable Lyapunov function, we establish the local and global stability of the disease-free equilibrium and the endemic equilibrium, respectively. Furthermore, in view of Schauder fixed point theorem, we show that the model admits traveling wave solutions con- necting the disease-free equilibrium and the endemic equilibrium when R0 〉 1 and c 〉 c^＊. And also, by virtue of the two-sided Laplace transform, we prove that the model has no traveling wave solution connecting the two equilibria when R0 〉 1 and c ∈（0, c^＊）.

关键词： SIS epidemic model traveling wave solution local stability global stability diffusive.

A Parameter-Free Approach to Determine the Lagrange Multiplier in the Level Set Method by Using the BESO

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Computer Modeling in Engineering & Sciences 2021年第7期128卷 283-295页

作者： Zihao Zong Tielin Shi qi xia The State Key Laboratory of Digital Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhanChina

A parameter-free approach is proposed to determine the Lagrange multiplier for the constraint of material volume in the level set *** is inspired by the procedure of determining the threshold of sensitivity number in the BESO *** first computes the difference between the volume of current design and the upper bound of ***,the Lagrange multiplier is regarded as the threshold of sensitivity number to remove the redundant *** examples proved that this approach is effective to constrain the *** importantly,there is no parameter in the proposed approach,which makes it convenient to *** addition,the convergence is stable,and there is no big oscillation.

关键词： Lagrange multiplier threshold of sensitivity BESO method level set method topology optimization

An M-VCUT level set-based data-driven model of microstructures and optimization of two-scale structures

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Frontiers of Mechanical Engineering 2024年第4期19卷 73-86页

作者： Minjie SHAO Tielin SHI qi xia State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China

The optimization of two-scale structures can adapt to the different needs of materials in various regions by reasonably arranging different microstructures at the macro scale,thereby considerably improving structural ***,a multiple variable cutting(M-VCUT)level set-based data-driven model of microstructures is presented,and a method based on this model is proposed for the optimal design of two-scale *** geometry of the microstructure is described using the M-VCUT level set method,and the effective mechanical properties of microstructures are computed by the homogenization ***,a database of microstructures containing their geometric and mechanical parameters is *** two sets of parameters are adopted as input and output datasets,and a mapping relationship between the two datasets is established to build the data-driven model of *** the optimization of two-scale structures,the data-driven model is used for macroscale finite element and sensitivity *** efficiency of the analysis and optimization of two-scale structures is improved because the computational costs of invoking such a data-driven model are much smaller than those of homogenization.

关键词： two-scale structure structural optimization M-VCUT level set homogenization radial basis function data-driven