Four-Point Wavelets and Their Applications

Multiresolution analysis(MRA)and wavelets provide useful and efficient tools for representing functions at multiple levels of details.Wavelet representations have been used in a broad range of applications ,including image compression,physical simulation and numerical analysis,In this paper,the authors construct a new class of wavelets,called four-point wavelets,based on an interpolatory four-point subdvision scheme.They are of local support,symmetric and stable.The analysis and synthesis algorithms have linear time complexity,Depending on different weight parameters w.the scaling functions and wavelets generated by the four-point subdivision scheme are of different degrees of smoothness.Therefore th user can select better wavelets relevant to the practice among the classes of wavelets.The authors apply the four-point wavelets in signal compression.The results show that the four-point wavelets behave much better than B-spline wavelets in many situations.     

RR压缩机防喘振控制浅析

介绍了RR压缩机防喘控制系统的基本原理及软硬件平台,分析防喘振系统仪表信号滤波方法,建立防喘控制特性曲线,梳理防喘控制逻辑以及防喘PID控制算法。     

云广特高压800kV直流过压保护特性分析

云广特高压直流输电工程中的直流过压保护功能是检测由直流回路开路、逆变器闭锁或控制系统故障引起的直流过电压情况.在直流线路开路或逆变器闭锁的情况下,整流站可能试图运行,引起直流电压升高,该保护动作将整流站 ESOF跳闸。文章对直流过压保护功能特性进行分析,并对该功能在实际运行中出现的拒动问题提出了改进措施。