Nonlinear approximation is widely used in signal processing. Real-life signals can be modeled as functions of bounded variation. Thus the variable knot of approximating function could be self- adaptively chosen by bal...Nonlinear approximation is widely used in signal processing. Real-life signals can be modeled as functions of bounded variation. Thus the variable knot of approximating function could be self- adaptively chosen by balancing the total variation of the target function. In this paper, we adopt continuous piecewise linear approximation instead of the existing piecewise constants approximation. The results of experiments show that this new method is superior to the old one.展开更多
The methods employed in recent years to retrieve vector wind information from single-Doppler radar observation are reviewed briefly. These methods are based on a linearity hypothesis for the wind field, so the retriev...The methods employed in recent years to retrieve vector wind information from single-Doppler radar observation are reviewed briefly. These methods are based on a linearity hypothesis for the wind field, so the retrieved wind field is sometimes negatively affected by the non-linearity of wind. This paper proposes a new method based on a non-linear approximation technique. This method, which relies on the piecewise smooth property of the wind field and makes full use of the radar velocity data, is applied to two cases of the Huaihe River Basin Energy and Water Cycle Experiment (HUBEX) in 1998. Checked against the wind field observed by dual-Doppler radar, the retrieved wind field by the method presented in this paper yields a relatively accurate horizontal vector wind field with high resolution, as well as a reasonable estimate of the magnitude of vertical velocity.展开更多
首先,设计了节点自适应传感半径调整算法(AASR,adaptive adjustment of sensing radius),通过节点自适应选择最佳的覆盖范围,有效地进行节点覆盖控制,减少节点能量虚耗,提高覆盖效率。其次,从调整效果、能量消耗和覆盖冗余度3个方面对...首先,设计了节点自适应传感半径调整算法(AASR,adaptive adjustment of sensing radius),通过节点自适应选择最佳的覆盖范围,有效地进行节点覆盖控制,减少节点能量虚耗,提高覆盖效率。其次,从调整效果、能量消耗和覆盖冗余度3个方面对节点自适应传感半径调整算法进行了模拟实验和分析。仿真结果表明,AASR能够有效提高节点生存时间,减少能量消耗,提高覆盖率。展开更多
This paper investigates the stability analysis with respect to part of the variables of nonlinear time-varying systems with impulse effect.The approach presented is based on the specially introduced piecewise continuo...This paper investigates the stability analysis with respect to part of the variables of nonlinear time-varying systems with impulse effect.The approach presented is based on the specially introduced piecewise continuous Lyapunov functions.The Lyapunov stability theorems with respect to part of the variables are generalized in the sense that the time derivatives of the Lyapunov functions are allowed to be indefinite.With the help of the notion of stable functions,asymptotic partial stability,exponential partial stability,input-to-state partial stability(ISPS)and integral input-to-state partial stability(iISPS)are considered.Three numerical examples are provided to illustrate the effectiveness of the proposed theoretical results.展开更多
分片线性函数是一元分段线性函数在多元情况下的推广,它在沟通模糊系统和被逼近函数关系中起着重要的桥梁作用.文章基于多元连续函数的网格分片线性函数(grid piecewise linear function,GPLF)重新构造了非齐次线性T-S模糊系统,并依据...分片线性函数是一元分段线性函数在多元情况下的推广,它在沟通模糊系统和被逼近函数关系中起着重要的桥梁作用.文章基于多元连续函数的网格分片线性函数(grid piecewise linear function,GPLF)重新构造了非齐次线性T-S模糊系统,并依据行列式性质和矩阵模证明了当规则后件线性部分所有参数选取非零常数时该系统对GPLF也具有逼近性.进而在最大模意义下获得该线性T-S模糊系统对连续函数类构成逼近器.此外,通过模拟实例对非齐次线性T-S模糊系统进行逼近精度分析.结果显示,该非齐次线性T-S模糊系统可按任意精度逼近所给连续函数.展开更多
文摘Nonlinear approximation is widely used in signal processing. Real-life signals can be modeled as functions of bounded variation. Thus the variable knot of approximating function could be self- adaptively chosen by balancing the total variation of the target function. In this paper, we adopt continuous piecewise linear approximation instead of the existing piecewise constants approximation. The results of experiments show that this new method is superior to the old one.
基金The authors would like to express their thanks to the GAME/HUBEX Project Office for assistance.
文摘The methods employed in recent years to retrieve vector wind information from single-Doppler radar observation are reviewed briefly. These methods are based on a linearity hypothesis for the wind field, so the retrieved wind field is sometimes negatively affected by the non-linearity of wind. This paper proposes a new method based on a non-linear approximation technique. This method, which relies on the piecewise smooth property of the wind field and makes full use of the radar velocity data, is applied to two cases of the Huaihe River Basin Energy and Water Cycle Experiment (HUBEX) in 1998. Checked against the wind field observed by dual-Doppler radar, the retrieved wind field by the method presented in this paper yields a relatively accurate horizontal vector wind field with high resolution, as well as a reasonable estimate of the magnitude of vertical velocity.
文摘首先,设计了节点自适应传感半径调整算法(AASR,adaptive adjustment of sensing radius),通过节点自适应选择最佳的覆盖范围,有效地进行节点覆盖控制,减少节点能量虚耗,提高覆盖效率。其次,从调整效果、能量消耗和覆盖冗余度3个方面对节点自适应传感半径调整算法进行了模拟实验和分析。仿真结果表明,AASR能够有效提高节点生存时间,减少能量消耗,提高覆盖率。
文摘This paper investigates the stability analysis with respect to part of the variables of nonlinear time-varying systems with impulse effect.The approach presented is based on the specially introduced piecewise continuous Lyapunov functions.The Lyapunov stability theorems with respect to part of the variables are generalized in the sense that the time derivatives of the Lyapunov functions are allowed to be indefinite.With the help of the notion of stable functions,asymptotic partial stability,exponential partial stability,input-to-state partial stability(ISPS)and integral input-to-state partial stability(iISPS)are considered.Three numerical examples are provided to illustrate the effectiveness of the proposed theoretical results.
文摘分片线性函数是一元分段线性函数在多元情况下的推广,它在沟通模糊系统和被逼近函数关系中起着重要的桥梁作用.文章基于多元连续函数的网格分片线性函数(grid piecewise linear function,GPLF)重新构造了非齐次线性T-S模糊系统,并依据行列式性质和矩阵模证明了当规则后件线性部分所有参数选取非零常数时该系统对GPLF也具有逼近性.进而在最大模意义下获得该线性T-S模糊系统对连续函数类构成逼近器.此外,通过模拟实例对非齐次线性T-S模糊系统进行逼近精度分析.结果显示,该非齐次线性T-S模糊系统可按任意精度逼近所给连续函数.
