In this paper a meshless method of lines is proposed for the numerical solution of time-dependent nonlinear coupled partial differential equations. Contrary to mesh oriented methods of lines using the finite-differenc...In this paper a meshless method of lines is proposed for the numerical solution of time-dependent nonlinear coupled partial differential equations. Contrary to mesh oriented methods of lines using the finite-difference and finite element methods to approximate spatial derivatives, this new technique does not require a mesh in the problem domain, and a set of scattered nodes provided by initial data is required for the solution of the problem using some radial basis functions. Accuracy of the method is assessed in terms of the error norms L2, L∞ and the three invariants C1, C2, C3. Numerical experiments are performed to demonstrate the accuracy and easy implementation of this method for the three classes of time-dependent nonlinear coupled partial differential equations.展开更多
在海洋资源勘测和环境监测活动中,常需要准确测量水下声速信息。利用TDC-GP22设计了一种低成本的小型化声速仪,针对飞行时间(Time of Flight,TOF)法测声速过程中存在的超声波衰减等问题,提出了一种基于首波脉冲宽度的可变阈值算法,根据...在海洋资源勘测和环境监测活动中,常需要准确测量水下声速信息。利用TDC-GP22设计了一种低成本的小型化声速仪,针对飞行时间(Time of Flight,TOF)法测声速过程中存在的超声波衰减等问题,提出了一种基于首波脉冲宽度的可变阈值算法,根据回波信号的首波脉冲宽度值动态调整检测阈值,提高了测量结果的稳定性。同时通过分析声速测量过程中的常见误差来源,在系统动态标定环节设计了一种基于RBF神经网络的温度补偿算法,校准了温度带来的换能器频率偏移以及声电延时等误差。在不同温盐条件下的声速测量结果表明该系统能以较低的成本获取高精度水下声速信息。展开更多
文摘In this paper a meshless method of lines is proposed for the numerical solution of time-dependent nonlinear coupled partial differential equations. Contrary to mesh oriented methods of lines using the finite-difference and finite element methods to approximate spatial derivatives, this new technique does not require a mesh in the problem domain, and a set of scattered nodes provided by initial data is required for the solution of the problem using some radial basis functions. Accuracy of the method is assessed in terms of the error norms L2, L∞ and the three invariants C1, C2, C3. Numerical experiments are performed to demonstrate the accuracy and easy implementation of this method for the three classes of time-dependent nonlinear coupled partial differential equations.
文摘在海洋资源勘测和环境监测活动中,常需要准确测量水下声速信息。利用TDC-GP22设计了一种低成本的小型化声速仪,针对飞行时间(Time of Flight,TOF)法测声速过程中存在的超声波衰减等问题,提出了一种基于首波脉冲宽度的可变阈值算法,根据回波信号的首波脉冲宽度值动态调整检测阈值,提高了测量结果的稳定性。同时通过分析声速测量过程中的常见误差来源,在系统动态标定环节设计了一种基于RBF神经网络的温度补偿算法,校准了温度带来的换能器频率偏移以及声电延时等误差。在不同温盐条件下的声速测量结果表明该系统能以较低的成本获取高精度水下声速信息。
