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Search Results: 1 - 10 of 52639 matches for " Qiang Xu "
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A Data-Placement Strategy Based on Genetic Algorithm in Cloud Computing  [PDF]
Qiang Xu, Zhengquan Xu, Tao Wang
International Journal of Intelligence Science (IJIS) , 2015, DOI: 10.4236/ijis.2015.53013
Abstract: With the development of Computerized Business Application, the amount of data is increasing exponentially. Cloud computing provides high performance computing resources and mass storage resources for massive data processing. In distributed cloud computing systems, data intensive computing can lead to data scheduling between data centers. Reasonable data placement can reduce data scheduling between the data centers effectively, and improve the data acquisition efficiency of users. In this paper, the mathematical model of data scheduling between data centers is built. By means of the global optimization ability of the genetic algorithm, generational evolution produces better approximate solution, and gets the best approximation of the data placement at last. The experimental results show that genetic algorithm can effectively work out the approximate optimal data placement, and minimize data scheduling between data centers.
Convergence rates for general elliptic homogenization problems in a bounded Lipschitz domain
Qiang Xu
Mathematics , 2015,
Abstract: In this paper, without smoothness assumptions on coefficients, we extend the results of $L^2$ convergence rates obtained by C. Kenig, F. Lin and Z. Shen in \cite{SZW2} to more general elliptic operators with Dirichlet or Neumann boundary conditions in a bounded Lipschitz domain, arising in homogenization theory. However, we do not repeat their arguments. Instead we find the new weighted estimates for the smoothing operator at scale $\varepsilon$, and combining some techniques developed by Z. Shen in \cite{SZW12} leads to our main results. In addition, we also obtain a sharp $O(\varepsilon)$ convergence rates in $L^{p}$ with $p=2d/(d-1)$, which was originally established by Z. Shen for elasticity systems in \cite{SZW12}. Also, this work may be regarded as the extension of \cite{TS,TS2} developed by T. Suslina concerned with the bounded Lipschitz domain.
Uniform Regularity Estimates in Homogenization Theory of Elliptic System with Lower Order terms
Qiang Xu
Mathematics , 2015,
Abstract: In this paper, we extend the uniform regularity estimates obtained by M. Avellanda and F. Lin in the paper of Compactness methods in the theory of homogenization (Comm. Pure Appl. Math. 40(1987), no.6, 803-847) to the more general second order elliptic systems in divergences form, with rapidly oscillating periodic coefficients. We establish not only sharp $W^{1,p}$ estimates, Holder estimates, Lipschitz estimates and non-tangential maximal function estimates for the Dirichelt problem on a $C^{1,\eta}$ domain, but also a sharp $O(\varepsilon)$ convergence rate in $H_0^1(\Omega)$ by virtue of the Dirichlet correctors. The well known compactness methods are not employed here, instead we construct the transformations to make full use of the corresponding results developed by M. Avellanda and F. Lin.
Uniform Regularity Estimates in Homogenization Theory of Elliptic Systems with Lower Order Terms on the Neumann Boundary Problem
Qiang Xu
Mathematics , 2015,
Abstract: In this paper, we mainly employed the idea of the previous paper to study the sharp uniform $W^{1,p}$ estimates with $1
Probability Analysis for the Damage of Gravity Dam  [PDF]
Qiang Xu, Jing Li, Jianyun Chen
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.34036
Abstract: Damage reliability analysis is an emerging field of structural engineering which is very significant in structures of great importance like arch dams, large concrete gravity dams etc. The research objective is to design and construct an improved method for damage reliability analysis for concrete gravity dam. Firstly, pseudo excitation method and Mazar damage model were used to analyze how to calculate damage expected value excited by random seismic loading and deterministic static load on the condition that initial elastic modulus was deterministic. Moreover, response surface method was improved from the aspects of the regression of sample points, the selection of experimental points, the determined method of weight matrix and the calculation method of checking point respectively. Then, the above method was used to analyze guarantee rate of damage expected value excited by random seismic loading and deterministic static load on the condition that initial elastic modulus was random. Finally, a test example was given to verify and analyze the convergence and stability of this method. Compared with other conventional algorithm, this method has some strong points: this algorithm has good convergence and stability and greatly enhances calculation efficiency and the storage efficiency. From what has been analyzed, we find that damage expected value is insensitive to the randomness of initial elastic modulus so we can neglect the randomness of initial elastic modulus in some extent when we calculate damage expected value.
A Study on the Functional Reliability of Gravity Dam  [PDF]
Qiang Xu, Jianyun Chen, Jing Li
Energy and Power Engineering (EPE) , 2012, DOI: 10.4236/epe.2012.42009
Abstract: The research objective is to design and construct a method for functional reliability analysis of concrete gravity dam. Firstly, the pseudo excitation method was utilized to analyze to calculate the probabilistic characteristics of concrete gravity dam excited by random seismic loading. Meanwhile, the response surface method based on weighted regression was associated to that method to analyze functional reliability of concrete gravity dam. Eventually, a test example was given to verify and analyze the convergence and stability of this method.
Cloning and phylogenetic analyses of serine/threonine kinase class defense-related genes in a wild fruit crop 'chestnut rose'
Qiang Xu, Xiuxin Deng
BMC Research Notes , 2010, DOI: 10.1186/1756-0500-3-202
Abstract: Serine/threonine kinase (STK) genes, encoding one of the important proteins for defense signal transduction, were cloned from 'chestnut rose'. Fifteen STK sequences were obtained by degenerate PCR. Sequence analysis showed that nine of them have continued open reading frames, and they are separated into five classes based on sequence analysis. Interestingly, one of the classes (STK V) showed less than 40% similarity to any other class, possibly representing new type genes from chestnut rose. Southern blotting analysis revealed that the new type STK V genes are single copy, while all the other genes have several copies in the genome. Phylogenetic analysis of STK genes from chestnut rose and 21 plant species revealed that most chestnut rose genes show close relationship with Rosaceae homologs, while the STK V genes are rather ancient and form a unique clade distantly from plant homologs.We cloned nine STK genes from a wild fruit crop 'chestnut rose', of which a new type of STK genes was identified. The new type STK genes exist as single copies in the genome, and they are phylogenetically distant to plant homologs. The polymorphic STK genes, combined with other plant immunity genes, provide plenty of resources to be utilized to defend against pathogens attack.Chestnut rose (Rosa roxburghii Tratt), a wild fruit crop in Southwest China, belongs to Rosaceae family Rosa genus. It has recently been labeled as one of the three promising new fruit crops in China due to its fruit having high content of vitamin C (2000-3000 mg/100 g FW), displaying high levels of superoxide dismutase (SOD) activity, and therefore is believed to have senescence-retarding and cancer-preventing effects [1]. Unfortunately, chestnut rose crops are suffering from powdery mildew disease. After decades of breeding, an indigenous cultivar from Guizhou province of China, Guinong No. 6, was discovered to be highly resistant to powdery mildew [2]. This material provides an opportunity to investigate the me
The characters of nonlinear vibration in the two-dimensional discrete monoatomic lattice
Quan Xu,Qiang Tian
Chinese Science Bulletin , 2005, DOI: 10.1360/04ww0068
Abstract: The two-dimensional discrete monoatomic lattice is analyzed. Taking nearest-neighbor interaction into account, the characters of the nonlinear vibration in two-dimensional discrete monoatomic lattice are described by the two-dimensional cubic nonlinear Schrodinger equation. Considering the quartic nonlinear potential, the two-dimensional discrete-soliton trains and the solutions perturbed by the neck mode are presented.
Bo Liu,Qiang Xu
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809012604
Abstract: The title compound, [Zn(C14H8N2O4)(H2O)2]n, consists of zigzag chains of Zn atoms bridged by azobenzene-4,4′-dicarboxylate ligands. The ZnII atom, lying on a twofold rotation axis, is coordinated by four O atoms from the carboxylate groups and two water molecules, giving rise to a considerably distorted octahedral coordination envionment. The ligand lies on an inversion center. In the crystal structure, π–π interactions between the ligands [interplanar distance = 3.527 (3) ] assemble the chains into a sheet-like structure. O—H...O hydrogen bonds between the coordinated water molecules and carboxylate O atoms connect the sheets into a three-dimensional network.
A Fully Discrete Symmetric Finite Volume Element Approximation of Nonlocal Reactive Flows in Porous Media
Zhe Yin,Qiang Xu
Mathematical Problems in Engineering , 2013, DOI: 10.1155/2013/175904
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