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Scenario simulation and forecast of land use/cover in northern china

Chinese science Bulletin 2008年第9期53卷 1401-1412页

作者： LI YueChen 1,2,3 & HE ChunYang 3 1 College of Geographical science, Chongqing normal university, Chongqing 400047, china 2 College of Resources and Environmental science, Chongqing university, Chongqing 400044, china 3 College of Resources science & technology, Beijing normal university, Beijing 100875, china College of Geographical science Chongqing Normal University Chongqing China College of Resources and Environmental science Chongqing University Chongqing China College of Resources science & technology Beijing Normal University Beijing China

Modeling land use/cover scenario changes and its potential impacts on structure and functions of ecosystem in typical regions are helpful to understanding the interactive mechanism between land use/cover system and ecosystem. Based on the analysis of the existing land use/cover simulation and forecast models, a land use/cover scenario dynamics model by the integration of System Dynamics (SD) model, Back Propagation Neural Network (BPNN) and Cellular Automata (CA) model is developed with land use/cover scenario changes in northern china in the next 30 years and simulated in this paper. The model is to simulate the land use/cover scenario demands by using a SD model at first, and then allocating the land use scenario patterns at the local scale with the considerations of land use/cover suitability, inheritance ability and neighborhood effect by using BPNN-CA model to satisfy the balance between land use/cover scenario demands and supplies. It integrates the advantages of SD, BPNN and CA. Macro-driving factors and the micro-spatial pattern are also fully taken into account. The BPNN simplifies the identification of the factors’ weights used in CA model and improves the reliability of the simulation results. The simulation accuracy of the model developed in this paper was found to be about 74%. It suggests that the model has the ability to reflect the complexity of land use/cover system at different scales to some extent and it is a useful tool for assessing the potential impacts of land use system on ecosystem. The simulated results also indicate that the urban land, water area and forest will increase significantly, and farmland and unable land will decrease gradually. Obvious land use/cover changes will take place in the farming-pastoral zone and the southeast area of northern china.

关键词：土地利用中国北方细胞自动机系统动力学

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Lp shape deformation

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science china(Information sciences) 2012年第5期55卷 983-993页

作者： GAO Lin1,ZHANG GuoXin 1 & LAI YuKun 2 1 Department of computer science and technology,Tsinghua university,Beijing 100084,china 2 school of computer science and Informatics,Cardiff university,Wales CF24 3AA,UK Department of computer science and technology Tsinghua University Beijing China school of computer science and Informatics Cardiff University Wales UK

Shape deformation is a fundamental tool in geometric *** methods consider preserving local details by minimizing some energy functional measuring local distortions in the L 2 *** strategy distributes distortions quite uniformly to all the vertices and penalizes ***,there is no unique answer for a natural deformation as it depends on the nature of the *** by recent sparse signal reconstruction work with non L 2 norm,we introduce general L p norms to shape deformation;the positive parameter p provides the user with a flexible control over the distribution of unavoidable *** with the traditional L 2 norm,using smaller p,distortions tend to be distributed to a sparse set of vertices,typically in feature regions,thus making most areas less distorted and structures better *** the other hand,using larger p tends to distribute distortions more evenly across the whole *** flexibility is often desirable as it mimics objects made up with different *** specifying varying p over the shape,more flexible control can be *** demonstrate the effectiveness of the proposed algorithm with various examples.

关键词： shape deformation Lp norm geometric modeling

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An Efficient Certificateless Ring Signature Scheme

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Wuhan university Journal of Natural sciences 2008年第5期13卷 567-571页

作者： ZHU Lijun ZHANG Futai College of Mathematics and computer science NanjingNormal University Nanjing 210097 Jiangsu China

To overcome the drawbacks such as high computational cost, unreasonable security model and long signature length in existing certificateless ring signature schemes, we propose an efficient certificateless ring signature scheme in this paper. Our construction is inspired by some efficient ID-based ring signature schemes, and uses bilinear pairings as a basic tool. Using a reasonable security model, the unforgeability of the proposed scheme is proven based on the intractability of the computational Diffie-Hellman （CDH） problem. The signature length of the new scheme is only ｜G2｜＋n｜G1｜（｜Gi｜ is the bit length of an element in group Gi, i =1, 2）. Compared with other existing certificateless ring signature schemes, the newly proposed scheme has a shorter signature length and is more efficient and practical.

关键词： certificateless ring signature unforgeability bilinear pairings CDH problem

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EXPONENTIAL ESTIMATES FOR STOCHASTIC DELAY EQUATIONS WITH NORM-BOUNDED UNCERTAINTIES

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Journal of Systems science & Complexity 2009年第2期22卷 324-332页

作者： Hongchu WANG Shigeng HU school of Mathematics science South China Normal University Guangzhou 510631 China. Department of Mathematics Huazhong University of Science and Technology Wuhan 430074 China.

This paper presents the sufficient conditions for the exponential stability of linear or semi-linear stochastic delay equations with time-varying norm bounded parameter ***-tial estimates for the solutions are also obtained by using a modified Lyapunov-Krasovski *** conditions can be tested numerically using interior point algorithms.

关键词： Exponential estimates time delay uncertainty.

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Numerical simulation of strain localization and damage evolution in large plastic deformation using mixed finite element method

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Journal of university of science and technology Beijing 2004年第3期11卷 273-277页

作者： Zhanghua Chen Jiajian Jin Jiumei Xiao Applied science school, university of science and technology Beijing, Beijing 100083, china Appl. Sci. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

An investigation of computer simulation is presented to analyze the effectsof strain localization and damage evolution in large plastic deformation. The simulation is carriedout by using an elastic-plastic-damage coupling finite element program that is developed based onthe concept of mixed interpolation of displacement/pressure. This program has been incorporated intoa damage mechanics model as well as the corresponding damage criterion. To illustrate theperformance of the proposed approach, a typical strain localization problem has been simulated. Theresults show that the proposed approach is of good capability to capture strain localization andpredict the damage evolution.

关键词： strain localization mixed element truesdell stress rate material damage

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An efficient and DoS-resistant user authentication scheme for two-tiered wireless sensor networks

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Journal of Zhejiang university-science C(computers and Electronics) 2011年第7期12卷 550-560页

作者： Rong FAN ,Dao-jing HE ,Xue-zeng PAN,Ling-di PING (school of computer science and technology,Zhejiang university,Hangzhou 310027,china) school of computer science and technology Zhejiang University Hangzhou China

Wireless sensor networks (WSNs) are vulnerable to security attacks due to their deployment and resource *** that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and denial-of-service (DoS)-resistant user authentication scheme for two-tiered *** proposed approach reduces the computational load,since it performs only simple operations,such as exclusive-OR and a one-way hash *** feature is more suitable for the resource-limited sensor nodes and mobile *** it is unnecessary for master nodes to forward login request messages to the base station,or maintain a long user *** addition,pseudonym identity is introduced to preserve user *** clever design,our proposed scheme can prevent smart card ***,security and performance analysis demonstrates the effectiveness and robustness of the proposed scheme.

关键词： User authentication User anonymity Smart card Two-tiered Wireless sensor network (WSN)

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A computational investigation of boron-doped chromium and chromium clusters by density functional theory

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science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 812-817页

作者： GE GuiXian1,JING Qun1 & LUO YouHua2,3 1 Key Laboratory of Ecophysics and Department of Physics,normal College,Shihezi university,Xinjiang 832003,china 2 school of science,East china university of science and technology,Shanghai 200237,china 3 Institute of Theoretical Physics,school of Physics and Information Optoelectronics,Henan university,Kaifeng 475004,china Key Laboratory of Ecophysics and Department of Physics Normal College Shihezi University Xinjiang China school of science East China University of Science and Technology Shanghai China Institute of Theoretical Physics School of Physics and Information Optoelectronics Henan University Kaifeng China

The geometries,stabilities and electronic properties of Crn and CrnB(n=2-9) clusters have been systematically investigated by density functional *** results suggest that the lowest energy structures for CrnB clusters can be obtained by substituting one Cr atom in Crn+1 clusters with B *** geometries of CrnB clusters are similar to that of Crn+1 clusters except for local structural *** second-order difference and fragmentation energy show Cr4,Cr6,Cr8,Cr3B,Cr5B and Cr8B cluster are the most stable among these studied *** impurity B increases the stabilities of chromium *** B is doped on the Crn clusters,cluster geometry does dominate positive role in enhancing their *** doped B atom does not change the coupling way of the Cr site in Crn clusters,but breaks the symmetry and the Cr atoms are no longer *** doped B atom increases the total magnetic moments of Crn in most cases.

关键词： Crn and CrnB clusters geometries electronic properties

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Genetic Algorithm for the Thermal Stresses Optimum Design ofFunctionally Gradient Material Plate

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International Journal of Minerals,Metallurgy and Materials 1999年第3期13卷 224-227页

作者： Xiaodan Zhang Zhengbin Tang Changchun Ge(Applied science school, university of science and technology Beijing, Beijing 100083, china) Applied science school University of Science and Technology Beijing Beijing 100083 China

Based on the thermal stress distribution for functionally gradient material (FGM) plates, a Genetic Algorithm (GA) method for the thermal stresses optimum design of FGM plate with computer technologies is given. The m... 详细信息

关键词： functionally gradient material (FGM) thermal stress Genetic Algorithm (GA) crossover mutation

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A Case Study of 3D Protein Structure Prediction with Genetic Algorithm and Tabu Search

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Wuhan university Journal of Natural sciences 2011年第2期16卷 125-129页

作者： WANG Ting1,2, ZHANG Xiaolong1, 3 1. school of computer science and technology, Wuhan university of science and technology, Wuhan 430065, Hubei, china 2. College of Mobile Telecommunications, Chongqing university of Posts and Telecommunications, Chongqing 400065, china 3. State Key Laboratory of Bioelectronics, Southeast university, nanjing 210096, china school of computer science and technology Wuhan University of Science and Technology Wuhan Hubei China College of Mobile Telecommunications Chongqing University of Posts and Telecommunications Chongqing China State Key Laboratory of Bioelectronics Southeast University Nanjing China

This paper describes a case study of 3D protein structure prediction of six sequences from protein data bank （PDB） by genetic algorithm and tabu search （GATS）, where off-lattice AB model is considered as a simplified model of protein structure. The lowest-energy values required for forming the native conformation of proteins are searched by GATS, and then the coarse structures （i.e., simplified structure） of the proteins are obtained according to the multiple angle parameters corresponding to the lowest energies. All the coarse structures form single hydrophobic cores surrounded by hydrophilic residues, which stay on the right side of the actual characteristic of protein structure. It demonstrates that this approach can predict the 3D protein structure effectively.

关键词： 3D protein structure off-lattice AB model genetic algorithm and tabu search (GATS)

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Reverse extraction of early-age hydration kinetic equation from observed data of Portland cement

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science china(Technological sciences) 2010年第6期53卷 1540-1553页

作者： WANG Lin1,YANG Bo2,ZHAO XiuYang1,2,CHEN YueHui2 & CHANG Jun3 1 school of computer science and technology,Shandong university,Jinan 250101,china 2 Provincial Key Laboratory for Network-based Intelligent Computing,university of Jinan,Jinan 250022,china 3 school of Material science and Engineering,university of Jinan,Jinan 250022,china school of computer science and technology Shandong University Jinan China Provincial Key Laboratory for Network-based Intelligent Computing University of Jinan Jinan China school of Material science and Engineering University of Jinan Jinan China

The early-age hydration of Portland cement paste has an important impact on the formation of microstructure and development of ***,manual derivation of hydration kinetic equation is very difficult because there are multi-phased,multi-sized and interrelated complex chemical and physical reactions during cement *** this paper,early-age hydration kinetic equation is reversely extracted automatically from the observed time series of hydration degree of Portland cement using evolutionary computation method that combines gene expression programming and particle swarm optimization *** order to reduce the computing time,GPUs are used for acceleration in *** have shown that according to the extracted kinetic equation,simulation curve of early-age hydration is in good accordance with the observed experimental ***,this equation still has a good generalization ability even changing chemical composition,particle size and curing conditions.

关键词： Portland cement hydration kinetic equation reverse extraction gene expression programming particle swarm optimization

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