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Cuckoo search with varied scaling factor

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Frontiers of Computer Science 2015年第4期9卷 623-635页

作者： lijin wang Yilong YIN Yiwen ZHONG School of Computer Science and Technology Shandong University Jinan 250101 China College of Computer and Information Science Fujian Agriculture and Forestry University Fuzhou 350002 China School of Computer Science and Technology Shandong University of Finance and Economics Jinan 250014 China

Cuckoo search （CS）, inspired by the obligate brood parasitic behavior of some cuckoo species, iteratively uses L6vy flights random walk （LFRW） and biased/selective random walk （BSRW） to search for new solutions. In this study, we seek a simple strategy to set the scaling factor in LFRW, which can vary the scaling factor to achieve better performance. However, choosing the best scaling factor for each problem is intractable. Thus, we propose a varied scal- ing factor （VSF） strategy that samples a value from the range [0,1] uniformly at random for each iteration. In addition, we integrate the VSF strategy into several advanced CS vari- ants. Extensive experiments are conducted on three groups of benchmark functions including 18 common test functions, 25 functions proposed in CEC 2005, and 28 functions intro- duced in CEC 2013. Experimental results demonstrate the ef- fectiveness of the VSF strategy.

关键词： cuckoo search algorithm uniform distribution,random sampling scaling factor function optimization prob-lems

The State Equations Methods for Stochastic Control Problems

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Numerical Mathematics(Theory,Methods and Applications) 2010年第1期3卷 79-96页

作者： lijin wang Fengshan Bai Department of Mathematical Sciences Tsinghua University Beijing 100084China. School of Mathematical Sciences Graduate University of Chinese Academy of Sciences Beijing 100049 China.

The state equations of stochastic control problems,which are controlled stochastic differential equations,are proposed to be discretized by the weak midpoint rule and predictor-corrector methods for the Markov chain approximation approach. Local consistency of the methods are *** tests on a simplified Merton's portfolio model show better simulation to feedback control rules by these two methods, as compared with the weak Euler-Maruyama discretisation used by *** suggests a new approach of improving accuracy of approximating Markov chains for stochastic control problems.

关键词： Stochastic optimal control Markov chain approximation Euler-Maruyama discretisation midpoint rule predictor-corrector methods portfolio management.

Sequential quadratic programming enhanced backtracking search algorithm

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Frontiers of Computer Science 2018年第2期12卷 316-330页

作者： Wenting ZHAO lijin wang Yilong YIN Bingqing wang Yuchun TANG School of Computer Science and Technology Shandong University Jinan 250101 China College of Computer and Information Science Fujian Agriculture and Forestry University Fuzhou 350002 China Research Center for Sectional and Imaging Anatomy Shandong University School of Medicine Jinan 250012 China

In this paper, we propose a new hybrid method called SQPBSA which combines backtracking search optimization algorithm （BSA） and sequential quadratic programming （SQP）. BSA, as an exploration search engine, gives a good direction to the global optimal region, while SQP is used as a local search technique to exploit the optimal solution. The experiments are carried on two suits of 28 functions proposed in the CEC-2013 competitions to verify the performance of SQPBSA. The results indicate the proposed method is effective and competitive.

关键词： numerical optimization backtracking search algorithm sequential quadratic programming local search

Stochastic Multi-Symplectic Integrator for Stochastic Nonlinear Schrodinger Equation

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Communications in Computational Physics 2013年第7期14卷 393-411页

作者： Shanshan Jiang lijin wang Jialin Hong College of Science Beijing University of Chemical TechnologyBeijing 100029P.R.China School of Mathematical Sciences Graduate University of Chinese Academy of SciencesBeijing 100049P.R.China State Key Laboratory of Scientific and Engineering Computing Institute of ComputationalMathematics and Scientific/Engineering ComputingAcademy of Mathematics and System ScienceChinese Academy of SciencesP.O.Box 2719Beijing 100190P.R.China

In this paper we propose stochastic multi-symplectic conservation law for stochastic Hamiltonian partial differential equations,and develop a stochastic multisymplectic method for numerically solving a kind of stochastic nonlinear Schrodinger *** is shown that the stochasticmulti-symplecticmethod preserves themultisymplectic structure,the discrete charge conservation law,and deduces the recurrence relation of the discrete *** experiments are performed to verify the good behaviors of the stochastic multi-symplectic method in cases of both solitary wave and collision.

关键词： Stochastic nonlinear Schrodinger equations stochasticmulti-symplectic Hamiltonian systems multi-symplectic integrators

Magnetic property and recording performance of chemical deposition CoP thin films

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Rare Metals 2012年第3期31卷 260-263页

作者： wang, Haicheng Zhou, Qunfei Teng, Jiao wang, lijin Yu, Guanghua Department of Material Physics and Chemistry University of Science and Technology Beijing Beijing 100083 China

The thickness of CoP thin films prepared by wet chemical deposition is of crucial importance on magnetic property and recording perform-ance. The coercivity of CoP films decreased with increasing film thickness. The coercivity was 45.37 kA m 1 at the thickness of 300 nm, and decreased to 21.65 kA m 1 at 5.7 μm. Recording performance tests indicate that, for drums with the same size, different recorded magnetic pole density have different thickness requirements. For 40 mm diameter magnetic drum, the optimal CoP thickness is 3～10 μm for 256 re-corded magnetic poles, 1～2 μm for 512 recorded magnetic poles, and 500～800 nm for 1024 recorded magnetic poles.

关键词： CoP thin films magnetic property magnetic recording

Preparation and magnetic properties of Co-P thin films

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Journal of University of Science and Technology Beijing 2008年第5期15卷 618-621页

作者： Haicheng wang Zhongmei Du lijin wang Guanghua Yu Fengwu Zhu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

Magnetic Co-P thin films were prepared by electroless deposition. The experiment results show that the film thickness has a significant influence on the coercivity. While the film thickness varied from 300 nm to 5 μm,the coercivity dropped sharply from 45.36 to 22.28 kA/m. As the film thickness increased further,the coercivity varied slowly. When the thickness of the film was 300 nm,the deposited film could realize the coercivity as high as 45.36 kA/m,and the remanent magnetization as high as 800 kA/m .The Co-P films were deposited on the surface of magnetic drums of encoders,whose diameter was 40 mm,and then 512 magnetic poles were recorded,meaning that the magnetizing pitch was 0.245 mm. The testing results indicate that the output signals are perfect,the output waveforms are steady and the pulses account is integral. Compared with the γ-Fe2O3 coating,the Co-P thin film is suitable to be the magnetic recording media for the high resolution magnetic rotary encoder.

关键词： magnetic thin film electroless deposition magnetic properties magnetic recording media

Accumulation and potential sources of heavy metals in soils of the Hetao area,Inner Mongolia,China

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Pedosphere 2020年第2期30卷 244-252页

作者： Yangchun ZHU lijin wang Xueyong ZHAO Jie LIAN Zhenhua ZHANG Ecology Institute Lishui UniversityLishui 323000China Institute of Agricultural Resource and Environmental Sciences Jiangsu Academy of Agricultural SciencesNanjing 210014China Northwest Institute of Eco-Environment and Resources Chinese Academy of SciencesLanzhou 730000China

Soil contamination by heavy metals is a problem in agricultural irrigation *** assess the accumulation and sources of heavy metals in the Yongji irrigation district of the Hetao area,Inner Mongolia,China,195 soil samples from 39 sites(0–100 cm)were collected,and Zn,Cu,Pb,Cr,and Cd concentrations were *** mean concentrations were 107.17,32.48,12.31,53.53,and 0.22 mg kg-1,respectively,with no significant differences between soil depths(P>0.05).Concentrations of Zn,Cu,and Cd were higher than the background levels,with moderate accumulation;the contamination factor(CF)values were 1.9,1.7,and 1.9,respectively,and the geoaccumulation index(Igeo)was>*** of Pb and Cr were lower than,or close to,the background levels(CF<1,Igeo<0),indicating that they originated from a natural *** monomial potential ecological risk index(Eri)for Zn,Cu,Pb,and Cr was low;Eri for Cd was 55.73,implying a moderate *** grade of potential ecological risk index of the five heavy metals(RI)was low,declining from south to *** studied soils were contaminated with Zn,Cu,and Cd;principal component(PC)analysis implicated the enrichment of Cd and partial Cu(high loading in PC 2)was related to agricultural activities;Zn and partial Cu,closely associated with PC 3,may have originated from irrigation water from the Yellow *** agricultural development should focus on fertilizer and pesticide application and the quality of irrigation water.

关键词： agricultural activity contamination factor geoaccumulation index potential ecological risk principal component analysis soil layer spatial distribution

A Symplectic Based Neural Network Algorithm for Quantum Controls under Uncertainty

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Communications in Computational Physics 2022年第5期31卷 1525-1545页

作者： Jingshi Li Song Chen lijin wang Yanzhao Cao Department of Mathematics and Statistics Nanjing University of Information Science and TechnologyNanjingJiangsu210044P.R.China Department of Mathematics&Statistics University of Wisconsin–La CrosseLa CrosseWI54601USA School of Mathematical Sciences University of Chinese Academy of SciencesBeijing100049P.R.China Department of Mathematics&Statistics Auburn UniversityAuburnAL36830USA

Robust quantum control with uncertainty plays a crucial role in practical quantum *** paper presents a method for solving a quantum control problem by combining neural network and symplecticfinite difference *** neural network approach provides a framework that is easy to establish and *** the same time,the symplectic methods possess the norm-preserving property for the quantum system to produce a realistic solution in *** construct a general high dimensional quantum optimal control problem to evaluate the proposed method and an approach that combines a neural network with forward Euler’s *** analysis and numerical experiments confirm that the neural network-based symplectic method achieves significantly better accuracy and robustness against noises.

关键词： Quantum(noise)control neural network symplectic methods norm-preservation

Nonperturbative effects of attraction on dynamical behaviors of glass-forming liquids

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Chinese Physics B 2020年第12期29卷 396-401页

作者： Xiaoyan Sun Haibo Zhang lijin wang Zexin Zhang Yuqiang Ma Wenzheng College of Soochow University Suzhou 215104China Center for Soft Condensed Matter Physics and Interdisciplinary Research Soochow UniversitySuzhou 215006China School of Physics and Materials Science Anhui UniversityHefei 230601China College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou 215123China National Laboratory of Solid State Microstructures and Department of Physics Nanjing UniversityNanjing 210093China

We investigate systematically the effects of the inter-particle attraction on the structure and dynamical behaviors of glass-forming liquids via molecular dynamics *** find that the inter-particle attraction does not influence the structure,but greatly affects the dynamics and dynamical heterogeneity of the *** the system changes from a purely repulsive glass-forming liquid to an attractive one,the dynamics slows down and the dynamical heterogeneity becomes greater,which is found interestingly to be associated with larger cooperative rearrangement regions(CRRs).Additionally,the structures of CRRs are observed to be compact in attractive glass-forming liquids but string-like in purely repulsive *** findings constitute an important contribution to the ongoing study of the role of attractions in properties of glasses and glass-forming liquids.

关键词： attractive glass dynamics dynamical heterogeneity cooperative rearrangement regions(CRRs)