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A stochastic policy search model for matching behavior

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science china(Information sciences) 2011年第7期54卷 1430-1443页

作者： CHENG ZhenBo 1,2,ZHANG yu 1 & DENG ZhiDong 1 1 State Key Laboratory on Intelligent technology and Systems,Tsinghua National Laboratory for Information science and technology,department of Computer science,Tsinghua university,beijing 100084,china 2 department of Computer science and technology,Zhejiang university of technology,Hangzhou 310014,china 1. State Key Laboratory on Intelligent technology and Systems Tsinghua National Laboratory for Information Science and Technology Department of Computer Science Tsinghua University Beijing 100084 China2. Department of Computer Science and Technology Zhejiang University of Technology Hangzhou 310014 China

The matching law is one of the basic empirical laws in decision theory,and it states that a subject’s preference to optional targets depends on which choices are *** this paper,we study the possible mechanisms that explain why subjects’ decisions often obey this *** the basis of reinforcement learning theory,we put forward a decision-making model in which the policy is updated by a policy parameter,and the model might be implemented in the brain through the prefrontal cortex and the basal ganglia neural *** on this model,an algorithm that satisfies the matching law is derived under some simple *** analysis and simulation results show that the decision behavior achieved by the algorithm obeys the matching *** addition,the matching behaviors in two classical experiments are reproduced using the *** results provide a reasonable strategy for the matching law and a useful computational tool for rewarded decision-making tasks.

关键词： policy model matching law reinforcement learning decision-making model

Constraints on smoothness parameter and dark energy using observational H(z) data

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Research in Astronomy and Astrophysics 2011年第2期11卷 125-136页

作者： Hao-Ran yu1,Tian Lan1,Hao-Yi Wan2,Tong-Jie Zhang1,3 and Bao-Quan Wang4 1 department of Astronomy,beijing Normal university,beijing 100875,china 2 Business Office,beijing Planetarium,beijing 100044,china 3 Center for High Energy physics,Peking university,beijing 100871,china 4 department of physics,Dezhou university,Dezhou 253023,china department of Astronomy Beijing Normal University Beijing 100875 China Business Office Beijing Planetarium Beijing 100044 China Center for High Energy physics Peking University Beijing 100871 China department of physics Dezhou University Dezhou 253023 China

With large-scale homogeneity,the universe is locally inhomogeneous,clustering into stars,galaxies and larger *** property is described by the smoothness parameter α which is defined as the proportion of matter in the form of intergalactic *** we consider the inhomogeneities over a small scale,there should be modifications of the cosmological distances compared to a homogenous *** and Roeder developed a second-order ordinary differential equation（D-R equation） that describes the angular diameter distance-redshift relation for inhomogeneous cosmological ***,we may obtain the D-R equation for observational H（z） data（OHD）.The density-parameter ΩM,the state of dark energy ω,and the smoothness-parameter α are constrained by a set of OHD in a spatially flat XCDM universe as well as a spatially flat XCDM *** using a χ2 minimization method,we get α = 0.81＋0.19-0.20 and ΩM = 0.32＋0.12-0.06 at the 1σ confidence *** we assume a Gaussian prior of ΩM = 0.26 ± 0.1,we get α = 0.93＋0.07-0.19 and ΩM = 0.31＋*** the XCDM model,α is constrained to α≥ 0.80 but ω is weakly constrained around-1,where ω describes the equation of state of the dark energy（pX = ωρX）.We conclude that OHD constrains the smoothness parameter more effectively than the data of SNe Ia and compact radio sources.

关键词： cosmology -- dark energy -- cosmological parameters

On the coupled NBEM and FEM for a class of nonlinear exterior Dirichlet problem in R^(2*)

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science china Mathematics 2004年第z1期47卷 181-189页

作者： WU Zhengpeng, KANG Tong & yu DehaoInstitute of Computational Mathematics and Scientific/Engineering Computing, Academy of Mathematics and System sciences, Chinese Academy of sciences, beijing 100080, china department of Applied Mathematics, beijing Broadcasting Institute, beijing 100024, china Combinatorial and Computational Mathematics Center, Pohang university of science and technology, Phoang 790-784, Republic of Korea Chinese Acad Sci Acad Math & Syst Sci Inst Computat Math & Sci Engn Comp Beijing 100080 Peoples R China beijing Broadcasting Inst Dept Appl Math Beijing 100024 Peoples R China Pohang Univ Sci & Technol Combinatorial & Computat Math Ctr Phoang 790784 South Korea

In this paper, based on the natural boundary reduction advanced by Feng and yu, we couple the finite elementapproach with the natural boundary element method to study theweak solvability and Galerkin approximation of a class ofnonlinear exterior boundary value problems. The analysis is mainlybased on the variational formulation with *** provethe error estimate of the finite element solution and obtain theasymptotic rate of convergence. Finally, we also give anumerical example.

关键词： natural boundary integral method, finite element method, coupling method, error estimate.

Inverse Modeling of Nonlinear Systems and Application

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International Journal of Minerals,Metallurgy and materials 1999年第4期13卷 302-305页

作者： Jianping Wei Huade Li Datai yu(Information Engineering school, university’ of science and technology’ Beijng, beijing 1 00083, china) Information Engineering School University of Science and Technology Beijing Beijing 100083 China

Inverse modeling is discussed based on neural networks. U-D factorization Kalman filter learning algorithm is introduced totrain a feed forward multilayer neural network, which is used as inverse models. A scheme of D... 详细信息

关键词： neural network modeling control DC EAF

Modified chaotic ant swarm to function optimization

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The Journal of china Universities of Posts and Telecommunications 2009年第1期16卷 58-63页

作者： LI yu-ying , WEN Qiao-yan, LI Li-xiang State Key Laboratory of Networking and Switching technology, beijing university of Posts and Telecommunications, beijing 100876, china [a]State Key Laboratory of Networking and Switching technology beijing university of Posts and Telecommunications beijing 100876 china

The chaotic ant swarm algorithm （CAS） is an optimization algorithm based on swarm intelligence theory, and it is inspired by the chaotic and self-organizing behavior of the ants in nature. Based on the analysis of the properties of the CAS, this article proposes a variation on the CAS called the modified chaotic ant swarm （MCAS）, which employs two novel strategies to significantly improve the performance of the original algorithm. This is achieved by restricting the variables to search ranges and making the global best ant to learn from different ants＇ best information in the end. The simulation of the MCAS on five benchmark functions shows that the MCAS improves the precision of the solution.

关键词： chaotic ant swarm benchmark functions modified chaotic ant swarm swarm intelligence

Covarying modes of the Pacific SST and northern hemispheric midlatitude atmospheric circulation anomalies during winter

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Progress in Natural science:materials International 2008年第10期18卷 1261-1270页

作者： Yimin Zhu~(a,b,*) Xiuqun Yang~a Qian Xie~b Yongqiang yu~c ~a department of A tmospheric science,Nanjing university,Nanjing 210093,china ~b Institute of Meteorology,PLA university of science and technology,Nanjing 211101,china ~c LASG,Institute of Atmospheric physics,Chinese Academy of sciences,beijing 100029,china department of Atmospheric science Nanjing University Nanjing 210093 China Institute of Meteorology PLA University of Science and Technology Nanjing 211101 China LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The interannual-to-interdecadal relationship between the Pacific sea surface temperature (SST) and the northern hemispheric midlati- tude’s atmosphere represented by the circumpolar vortex was documented with the global oceanic and atmospheric reanalysis data of recent 50 *** covarying modes of the Pacific SST and northern circumpolar vortex anomalies during winter were examined using the sin- gular value decomposition and wavelet analysis *** is the interannual,ENSO-related mode and the other is the interdecadal, North Pacific SST-related mode with a period of around 20 *** two modes exhibit distinct spatial *** the interannual mode,the SST anomaly is characterized by a typical ENSO pattern with the principal signature in the tropical eastern Pacific and secondary one in the central North Pacific,while the atmospheric anomaly is regional,characterized by a Pacific-North American *** the inter- decadal mode,large SST anomaly is located in the central North Pacific,while the atmospheric anomaly is zonally global,associated with the midlatitute’s standing long-wave *** the central North Pacific is colder,the long-wave is stronger,and vice *** investigations suggest that the interdecadal mode could involve an interaction between "two oceans and an atmosphere".

关键词： Sea surface temperature Atmospheric circulation ENSO Decadal variability

Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618

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Journal of materials science & technology 2000年第4期16卷 416-420页

作者： Kun yu, Songrui LI and Wenxian LI (department of materials science and Engineering, Central South university of technology, Changsha 410083, china) department of materials science and Engineering Central South University of Technology Changsha 410083 China

An experimental 2618(Al-Cu-Mg-Fe-Ni) alloy added with trace Sc and Zr was prepared by ingot metallurgy (IM) method. The aging behavior of the alloy was studied by Vickers hardness measurement at 200℃ and 300℃. and the tensile properties of alloy specimens were measured at 20℃, 200℃, 250℃ and 300℃. The microstructure was observed by using optical microscope, SEM and TEM. It was found that the addition of Sc and Zr to 2618 alloy resulted in a primary Al_3(Sc,Zr) phase which could refine the grain because it acts as nuclei of heterogeneous crystallization in the melt during solidification. The secondary Al_3(Sc,Zr) particles were full coherent with matrix and had obvious precipitation hardening effect. They also made the S' phase precipitate more homogeneous. So the strength of alloy increases at both ambient and elevated temperatures without a decrease of ductility. The ductile fracture of alloy occurs by microvoid nucleation, growth and coalescence, so the microvoid coalescence is the dominant fracture mechanism.

关键词： Sc Zr Effect of Trace Sc and Zr on the Mechanical Properties and Microstructure of A1 Alloy 2618

Ab initio molecular dynamics simulation of the atom packing and density of Al-Ni amorphous alloys

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science china(Technological sciences) 2010年第12期53卷 3175-3182页

作者： yu ChunYan1, HUI XiDong1, CHEN XiaoHua1, LIU XingJun1, LIN DeYe1, LIU ZiKui2 & CHEN GuoLiang1 1 State Key Laboratory for Advanced Metals and materials, university of science and technology beijing, beijing 100083, china 2 department of materials science and Engineering, Pennsylvania State university, university Park, PA 16802, USA 1. State Key Laboratory for Advanced Metals and materials University of Science and Technology Beijing Beijing 100083 China2. Department of Materials Science and Engineering Pennsylvania State University University Park PA 16802 USA

Al-Ni alloys have better glass forming ability (GFA) than other Al-based alloys. However, the relationship among the atomic arrangement, glass transition, packing density and composition hasn’t been systematically studied. In this paper the ab initio molecular dynamics simulation (AIMD) was performed on the atom packing and density of AlxNi100-x (x=80, 83, 85, 86, 87 and 90) alloys. The pair correlation function and Voronoi tessellation indicated that there are obvious topological and chemical short-range orders in these alloys. The topological structure consists of Al-centered icosahedra like and Ni-centered tri-capped trigonal prism (TTP) like polyhedra. There is strong chemical short-range ordering between Al and Ni atoms indicated by the bond-length of Al-Ni pair shorter than the sum of the radii of Al and Ni atoms, which increases with the increasing of Ni content. It is shown that the densities of amorphous alloys don’t agree with the linear law with a peak at x=85. Based on the features of the structure and density, it is concluded that Al-Ni alloys at x=84–86 have high GFA, which can be extended to multi-component Al-based alloys.

关键词： AIMD Al-Ni alloys density short-range order chemical short-range order

Formation of Intragranular Ferrite During Isothermal/Thermomechanical Processes in a Medium Carbon V-Ti-N Microalloyed Steel

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Journal of Iron and Steel Research International 2011年第S1期18卷 350-354页

作者： XU Lei 1,LIU Guo-quan 2,NIE yu-zhu 1,WANG Xue-hui 1,MA E 1 (1.Hebei Iron and Steel technology Research Institute,Shi Jiazhuang 050021,Hebei,china 2.School of materials science and Engineering /State Key Laboratory for Advanced Metals and materials,university of science and technology beijing,beijing 100083,china) Hebei Iron & Steel Technol Res Inst Shijiazhuang 050021 Hebei Peoples R China Univ Sci & Technol beijing Sch Mat Sci & Engn State Key Lab Adv Met & Mat Beijing 100083 Peoples R China

For a V-Ti-N microalloyed steel with 0.34%C-1.54%Mn,intragranular ferrite (IGF) was obtained in both isothermal austenite decomposition processes and thermomechanical processes simulating the industrial seamless tubing manufacture *** show that with decrease of the isothermal temperature in range of 600℃ down to 450℃,not only the morphology of IGF changed from equiaxed to acicular,but also the equiaxed IGF and the acicular IGF were *** importantly,it is found that the amount of equiaxed ferrite increased significantly in the thermomechanical process sample water quenched from 550℃ after 800℃ deformation than that in the isothermally treated sample at 550℃ sample without hot *** implies that appropriate controlled deformation with controlled cooling can significantly promote equiaxed IGF formation,and not solely rely on nucleation mechanisms related with *** deformation of austenite without dynamic and complete static recrystallization causes high energy regions,therefore further promotes the nucleation potency of IGF.

关键词： V-Ti-N microalloyed steel intragranular ferrite (IGF) isothermal treatment thermomechanical processes controlled cooling