This paper focuses on studying the Poisson theory and the integration method of dynamics of relative motion. Equations of a dynamical system of relative motion in phase space are given. Poisson theory of the system is...This paper focuses on studying the Poisson theory and the integration method of dynamics of relative motion. Equations of a dynamical system of relative motion in phase space are given. Poisson theory of the system is established. The Jacobi last multiplier of the system is defined, and the relation between the Jacobi last multiplier and the first integrals of the system is studied. Our research shows that for a dynamical system of relative motion, whose configuration is determined by n generalized coordinates, the solution of the system can be found by using the Jacobi last multiplier if （2n-1） first integrals of the system are known. At the end of the paper, an example is given to illustrate the application of the results.展开更多
An approach about large dynamic programming based on discrete linear system with a quadratic index function is proposed by importing two Lagrange multipliers.
Research of airport＇ s influence on regional economy is conducted based on system dynamics, combining with input- output method and multiplier effect. SD model was used for visualizing, modeling and simulating airpor...Research of airport＇ s influence on regional economy is conducted based on system dynamics, combining with input- output method and multiplier effect. SD model was used for visualizing, modeling and simulating airport-regional economy system behavior. Model validation using the example of the Xi＇ an airport proved model simulated system behavior accurately. Besides, the result of scenario development simulation provided a new perspective for the practice of airport management and policy-making.展开更多
为解决交替方向乘子法(alternating direction method of multipliers,ADMM)正则化极限学习机(regularized extreme learning machine,RELM)迭代收敛速度慢和迭代后期误差衰减停滞的问题,提出一种基于动态步长ADMM的正则化极限学习机,记...为解决交替方向乘子法(alternating direction method of multipliers,ADMM)正则化极限学习机(regularized extreme learning machine,RELM)迭代收敛速度慢和迭代后期误差衰减停滞的问题,提出一种基于动态步长ADMM的正则化极限学习机,记为VAR-ADMM-RELM.该算法在ADMM算法的基础上采用动态衰减步长进行迭代,并同时使用L1和L2正则化对模型复杂度进行约束,解得具有稀疏性和鲁棒性的极限学习机输出权重.在UCI和MedMNIST数据集中对VAR-ADMM-RELM、极限学习机(extreme learning machine,ELM)、正则化极限学习机(regularized ELM,RELM)和基于ADMM的L1正则化ELM(ADMMRELM)进行拟合、分类和回归对比实验.结果表明,VAR-ADMM-RELM算法的平均分类准确率和平均回归预测精度分别比ELM算法提升了1.94%和2.49%,较标准ADMM算法可以取得3~5倍的速度提升,且对异常值干扰具有更好的鲁棒性和泛化能力,在高维度多样本的场景下建模效率逼近标准极限学习机.该方法有效提升了ADMM算法的收敛速度,取得了比主流ELM算法更加优秀的性能表现.展开更多
针对双有源桥DC-DC(dual active bridge,DAB)变换器中存在较大的电流应力现象,提出一种基于功率补偿的电流应力改进控制方法。通过建立DAB的电流应力、传输功率与相移量之间的函数关系,利用拉格朗日乘数法建立电流应力的优化数学模型,...针对双有源桥DC-DC(dual active bridge,DAB)变换器中存在较大的电流应力现象,提出一种基于功率补偿的电流应力改进控制方法。通过建立DAB的电流应力、传输功率与相移量之间的函数关系,利用拉格朗日乘数法建立电流应力的优化数学模型,从而推导出最优占空比组合,降低电流应力至最小值。通过引入一个虚拟分量对传输功率进行实时补偿控制,以满足系统在输入、输出突变情况下的快速响应能力,提高DAB的动态特性。最后,通过搭建Matlab/Simulink仿真模型进行验证,通过仿真结果表明:基于功率补偿的电流应力优化控制方法的动态响应特性和ZVS特性明显优于传统控制方法,且在减小电流应力的同时也降低了回流功率,进一步验证了优化控制方法的正确性和优越性。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 10972151)
文摘This paper focuses on studying the Poisson theory and the integration method of dynamics of relative motion. Equations of a dynamical system of relative motion in phase space are given. Poisson theory of the system is established. The Jacobi last multiplier of the system is defined, and the relation between the Jacobi last multiplier and the first integrals of the system is studied. Our research shows that for a dynamical system of relative motion, whose configuration is determined by n generalized coordinates, the solution of the system can be found by using the Jacobi last multiplier if （2n-1） first integrals of the system are known. At the end of the paper, an example is given to illustrate the application of the results.
文摘An approach about large dynamic programming based on discrete linear system with a quadratic index function is proposed by importing two Lagrange multipliers.
文摘Research of airport＇ s influence on regional economy is conducted based on system dynamics, combining with input- output method and multiplier effect. SD model was used for visualizing, modeling and simulating airport-regional economy system behavior. Model validation using the example of the Xi＇ an airport proved model simulated system behavior accurately. Besides, the result of scenario development simulation provided a new perspective for the practice of airport management and policy-making.
文摘针对双有源桥DC-DC(dual active bridge,DAB)变换器中存在较大的电流应力现象,提出一种基于功率补偿的电流应力改进控制方法。通过建立DAB的电流应力、传输功率与相移量之间的函数关系,利用拉格朗日乘数法建立电流应力的优化数学模型,从而推导出最优占空比组合,降低电流应力至最小值。通过引入一个虚拟分量对传输功率进行实时补偿控制,以满足系统在输入、输出突变情况下的快速响应能力,提高DAB的动态特性。最后,通过搭建Matlab/Simulink仿真模型进行验证,通过仿真结果表明:基于功率补偿的电流应力优化控制方法的动态响应特性和ZVS特性明显优于传统控制方法,且在减小电流应力的同时也降低了回流功率,进一步验证了优化控制方法的正确性和优越性。
