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3D thermo-hydro-mechanical-migratory coupling model and FEM analyses for dual-porosity medium

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Science china(Technological Sciences) 2010年第8期53卷 2172-2182页

作者： ZHANG YuJun 1&ZHANG WeiQing 2 1 State Key Laboratory of Geomechanics and Geotechnical engineering,Institute of Rock and Soil Mechanics, Chinese Academy of Sciences,Wuhan 430071,china 2school of Civil engineering,Southwest Jiaotong university,chengdu 610031,china 1. State Key Laboratory of Geomechanics and Geotechnical engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China2. School of Civil Engineering Southwest Jiaotong University Chengdu 610031 China

One kind of 3D coupled thermo-hydro-mechanical-migratory model for saturated-unsaturated dual-porosity medium was established,in which the stress field and the temperature field are single,but the seepage field and the concentration field are double,and the influences of sets,spaces,angles,continuity ratios,stiffness of fractures on the constitutive relationship of the medium can be *** relative three-dimensional program of finite element method was also *** comparing with the existing computation example,reliability of the model and the program were *** a hypothetical nuclear waste repository as a calculation example,the radioactive nuclide leak was simulated numerically with both the rock mass and the buffer being unsaturated media,and the temperatures,negative pore pressures,flow velocities,nuclide concentrations and normal stresses in the rock mass were *** results showed that the temperatures,negative pore pressures and nuclide concentrations in the buffer all present nonlinear changes and distributions that even though the saturation degree in porosity is only about 1/9 of that in fracture,the flow velocity of underground water in fracture is about 6 times of that in porosity because the permeability coefficient of fracture is almost four orders higher than that of porosity,and that the regions of stress concentration occur at the vicinity of two sides of the boundary between buffer and disposal pit wall.

关键词： dual-porosity medium thermo-hydro-mechanical-migratory coupling three-dimensional model FEM analysis

Geometric double-entity model for recognizing far-near relations of clusters

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Science china(Information Sciences) 2011年第10期54卷 2040-2050页

作者： WANG KaiJun ,YAN XuanHui & CHEN LiFei school of mathematics and computer Science,Fujian Normal university,Fuzhou 350108,china 1. school of mathematics and computer Science Fujian Normal University Fuzhou 350108 China

When solving many practical problems,we not only need sample labels given by a clustering algorithm,but also rely on the recognition of far-near relations of *** the difficult condition of many clusters in a high-dimensional data set,the clustering visualization methods based on dimension reductions usually produce the phenomena,e.g.,some clusters are overlapping,interlacing,or pushed away;as a result,the far-near relations of some clusters are displayed wrongly or cannot be *** existing inter-cluster distance methods cannot determine whether two clusters are far away or *** geometric double-entity model method (GDEM) is proposed to describe far-near relations of clusters,and the methods such as the relative border distance,absolute border distance and region dense degree are designed to measure far-near degrees between *** pays attention to both the absolute distance between nearest sample sets and the dense degrees of border regions of two clusters,and it is able to uncover accurately far-near relations of clusters in a high-dimensional space,especially under the difficult condition mentioned *** experimental results on four real data sets show that the proposed method can effectively recognize far-near relations of clusters,while the conventional methods cannot.

关键词： geometric double-entity model far-near relations of clusters distance between clusters partitional clustering algorithms

Tubular algebras and affine Kac-Moody algebras

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Science china mathematics 2007年第4期50卷 521-532页

作者： Zheng-xin CHEN & Ya-nan LIN school of mathematics and computer Science, Pujian Normal university, Fuzhou 350007, china school of Mathematical Sciences, Xiamen university, Xiamen 361005, china 1. school of mathematics and computer Science Fujian Normal University Fuzhou 350007 China 2. school of Mathematical Sciences Xiamen University Xiamen 361005 China

The purpose of this paper is to construct quotient algebras L(A) 1 ? /I(A) of complex degenerate composition Lie algebras L(A) 1 ? by some ideals, where L(A 1 ? is defined via Hall algebras of tubular algebras A, and to prove that the quotient algebras L(A) 1 ? /I(A) are isomorphic to the corresponding affine Kac-Moody algebras. Moreover, it is shown that the Lie algebra L re(A) 1 ? generated by A-modules with a real root coincides with the degenerate composition Lie algebra L(A) 1 ? generated by simple A-modules.

关键词： tubular algebras affine Kac-Moody algebras Hall algebras degenerate composition Lie algebras modules with real root 16G70 17B67

A centrality measure based on spectral optimization of modularity density

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Science china(Information Sciences) 2010年第9期53卷 1727-1737页

作者： FU LiDong1,2*,GAO Lin1 & MA XiaoKe1 1school of computer Science and engineering,Xidian university,Xi'an 710071,china 2College of computer,Xi'an university of Science and Technology,Xi'an 710054,china 1. school of computer Science and engineering Xidian University Xi’an 710071 China2. College of Computer Xi’an University of Science and Technology Xi’an 710054 China

Centrality analysis has been shown to be a valuable method for the structural analysis of complex *** is used to identify key elements within networks and to rank network elements such that experiments can be tailored to interesting *** this paper,we show that the optimization process of modularity density can be written in terms of the eigenspectrum of kernel *** on the eigenvectors belonging to the largest eigenvalue of kernel matrix,we present a new centrality measure that characterizes the contribution of each node to its assigned community in a network,called modularity density *** measure is illustrated and compared with the standard centrality measures by using respectively an artificial example and a classic network data *** statistical distribution of modularity density centrality is investigated by considering large computer generated graphs and two large networks from the real *** results show the significance of the proposed approach.

关键词： centrality modularity density centrality kernel matrix eigenspectrum

Experimental Study of Tunnel Fire with Natural Ventilation

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湖南大学学报（自然科学版） 2009年第S1期36卷 23-25页

作者： YUAN Zhong-yuan,LEI Bo,CHEN Peng-yun(school of Mechanical engineering,Southwest Jiaotong university,chengdu,Sichuan 610031,china) school of Mechanical engineering Southwest Jiaotong University Chengdu 610031 China

The 1/15 reduced-scale experiments using Froude scaling were designed to study the effect on the smoke control efficiency for subway tunnel fires with natural ventilation *** propane gas fires with heat release rate 11.48 kW was used,which corresponds to the heat release rate 10 MW in the full-scale *** temperature distributions under the ceiling were measured by K-type thermocouples to investigate smoke movement,and the velocity of smoke in shafts was measured by hot-wire anemometer to obtain the smoke extract amount of ventilation *** results show that the smoke temperature under the ceiling varies with the longitudinal different distance from fire *** results also show that the smoke temperature distributions and the smoke control efficiency in tunnel vary with the space between ventilation shafts and vary with the area and the height of ventilation shaft.

关键词： natural ventilation mode metro tunnel fire reduced-scale experiments froude scaling

Complexity of synthesis of composite service with correctness guarantee

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Science china(Information Sciences) 2012年第3期55卷 638-649页

作者： DENG Ting1,2 , HUAI JinPeng1,3 & WO TianYu1,3 1State Key Laboratory of Software Development Environment, Beihang university Beijing 100191, china 2school of mathematics and System Science, Beihang university, Beijing 100191, china 3school of computer Science and engineering, Beihang university, Beijing 100191, china 1. State Key Laboratory of Software Development Environment Beihang University Beijing 100191 China2. School of Mathematics and System Science Beihang University Beijing 100191 China3. School of Computer Science and Engineering Beihang University Beijing 100191 China

How to compose existing web services automatically and to guarantee the correctness of the design (e.g. temporal constraints specified by temporal logic LTL, CTL or CTL*) is an important and challenging problem in web services. Most existing approaches use the process in conventional software development of design, verification, analysis and correction to guarantee the correctness of composite services, which makes the composition process both complex and time-consuming. In this paper, we focus on the synthesis problem of composite service; that is, for a given set of services and correctness constraint specified by CTL or CTL* formula, a composite service is automatically constructed which guarantees that the correctness is ensured. We prove that the synthesis problem for CTL and CTL* are complete for EXPTIME and 2EXPTIME, respectively. Moreover, for the case of synthesis failure, we discuss the problem of how to disable outputs of environment (i.e. users or services) reasonably to make synthesis successful, which are also proved complete for EXPTIME and 2EXPTIME for CTL and CTL*, respectively.

关键词： business protocol composite service synthesis environment branching temporal logic

Adaptive detection for distributed targets in Gaussian noise with Rao and Wald tests

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Science china(Information Sciences) 2012年第6期55卷 1290-1300页

作者： SHUAI XiaoFei,KONG LingJiang & YANG JianYu school of Electronic engineering,university of Electronic Science and Technology of china,chengdu 610054,china 1. school of Electronic engineering University of Electronic Science and Technology of China Chengdu 610054 China

The problem of adaptively detecting a range distributed target or targets in Gaussian interference is considered in this *** is assumed that a set of secondary data is ***,we derive the adaptive Rao and Wald tests with one-step detection algorithm,and find that both of them are of the same asymptotic performance as the GLRT ***,the Rao and Wald tests are derived by resorting to the two-step design *** our surprise,our derivations show that all the Rao,Wald and GLR tests in the two-step design strategy are ***,the property assessments are *** is shown that these new detectors guarantee CFAR property with respect to the Gaussian ***,simulation results show that these results are accurate.

关键词： Rao and Wald tests adaptive detection distributed targets maximum likelihood estimator

Partitioning series-parallel multigraphs into υ*-excluding edge covers

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Science china mathematics 2006年第8期49卷 1082-1093页

作者： LIU Guizhen, DENG Xiaotie & XU Changqing school of mathematics and System Science, Shandong university, Jinan 250100, china Department of computer Science, City university of Hong Kong, Kowloon, Hong Kong, china Department of Applied mathematics, Hebei university of Technology, Tianjin 300130, china school of mathematics and System Science Shandong University Jinan 250100 China Department of computer Science City University of Hong Kong Kowloon Hong Kong Hong Kong Department of Applied mathematics Hebei University of Technology Tianjin 300130 China

We prove that, for any given vertexν* in a series-parallel graph G, its edge set can be partitioned into k= min{k′(G) + 1,δ(G)} subsets such that each subset covers all the vertices of G possibly except forν*, whereδ(G) is the minimum degree of G and k′(G) is the edge-connectivity of G. In addition, we show that the results in this paper are best possible and a polynomial time algorithm can be obtained for actually finding such a partition by our proof.

关键词： series-parallel graph, edge-connectivity, edge cover coloring, min-max theorem.

On the maximum likelihood method for target localization using MIMO radars

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Science china(Information Sciences) 2010年第10期53卷 2127-2137页

作者： XIA Wei , HE ZiShu & LIAO YuYu school of Electronic engineering, university of Electronic Science and Technology of china, chengdu 611731, china 1. school of Electronic engineering University of Electronic Science and Technology of China Chengdu 611731 China

A multiple-input multiple-output (MIMO) radar uses multiple antennas to simultaneously transmit multiple independent probing signals, and uses multiple antennas to receive the backscattered signals. The modeling of MIMO radar with transmit spatial diversity and coherent reception is addressed herein. The maximum likelihood (ML) method for parameter estimation using MIMO radars is considered, and two approximate ML algorithms are proposed. In the uniform noise scenario, one of the proposed algorithms performs similarly to the delay-and-sum beamformer which is optimal in the ML sense in single target case, while it outperforms the other proposed approximate ML algorithm at the cost of more computational load. In the non-uniform noise scenario, the proposed approximate ML algorithms both outperform the delay-and-sum beamformer. The efficiency of the proposed methods is validated by the simulation results.

关键词： maximum-likelihood multiple-input multiple-output (MIMO) radars parameter estimation