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英语写作僵化现象及对策 被引量:5
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作者 高涛 朱毅恒 陈懿 《湘潭师范学院学报(社会科学版)》 2007年第4期88-90,共3页
僵化是大学生英语写作的常见现象。过度概括、社交-语用失误以及语法词汇负迁移是其主要的原因。我们认为解决英语写作僵化的措施主要在于加强语言知识的积累,重视情感投入,选择语言最优化输入,改善学习环境,营造课堂气氛,融洽师生关系... 僵化是大学生英语写作的常见现象。过度概括、社交-语用失误以及语法词汇负迁移是其主要的原因。我们认为解决英语写作僵化的措施主要在于加强语言知识的积累,重视情感投入,选择语言最优化输入,改善学习环境,营造课堂气氛,融洽师生关系,合理编排教材,改进教学方法。 展开更多
关键词 僵化 英语写作 负迁移 最优化输入
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Nonholonomic motion planning for a free-falling cat using spline approximation 被引量:4
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作者 GE XinSheng GUO ZhengXiong 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2012年第11期2100-2105,共6页
An optimal motion planning of a free-falling cat based on the spline approximation is investigated.Nonholonomicity arises in a free-falling cat subjected to nonintegrable velocity constraints or nonintegrable conserva... An optimal motion planning of a free-falling cat based on the spline approximation is investigated.Nonholonomicity arises in a free-falling cat subjected to nonintegrable velocity constraints or nonintegrable conservation laws.The equation of dynamics of a free-falling cat is obtained by using the model of two symmetric rigid bodies.The control of the system can be converted to the motion planning problem for a driftless system.A cost function is used to incorporate the final errors and control energy.The motion planning is to determine control inputs to minimize the cost function and is formulated as an infinite dimensional optimal control problem.By using the control parameterization,the infinite dimensional optimal control problem can be transformed to a finite dimensional one.The particle swarm optimization(PSO) algorithm with the cubic spline approximation is proposed to solve the finite dimension optimal control problem.The cubic spline approximation is introduced to realize the control parameterization.The resulting controls are smooth and the initial and terminal values of the control inputs are zeros,so they can be easily generated by experiment.Simulations are also performed for the nonholonomic motion planning of a free-falling cat.Simulated experimental results show that the proposed algorithm is more effective than the Newtoian algorithm. 展开更多
关键词 falling cat nonholonomic constraint motion planning spline approximation particle swarm optimization
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