scholarly journals Model recovery for Hammerstein systems using the auxiliary model based orthogonal matching pursuit method

2018 ◽  
Vol 54 ◽  
pp. 537-550 ◽  
Author(s):  
Dongqing Wang ◽  
Liwei Li ◽  
Yan Ji ◽  
Yaru Yan
Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Shuo Zhang ◽  
Dongqing Wang ◽  
Yaru Yan

Hammerstein systems are formed by a static nonlinear block followed by a dynamic linear block. To solve the parameterizing difficulty caused by parameter coupling between the nonlinear part and the linear part in a Hammerstein system, an instrumental variable method is studied to parameterize the Hammerstein system. To achieve in simultaneously identifying parameters and orders of the Hammerstein system and to promote the computational efficiency of the identification algorithm, a sparsity-seeking orthogonal matching pursuit (OMP) optimization method of compressive sensing is extended to identify parameters and orders of the Hammerstein system. The idea is, by the filtering technique and the instrumental variable method, to transform the Hammerstein system into a simple form with a separated nonlinear expression and to parameterize the system into an autoregressive model, then to perform an instrumental variable-based orthogonal matching pursuit (IV-OMP) identification method for the Hammerstein system. Simulation results illustrate that the investigated method is effective and has advantages of simplicity and efficiency.


Author(s):  
Ahmed Omara ◽  
Alaa Hefnawy ◽  
Abdelhalim Zekry

<p>In this paper, we have addressed the issue of the sparse compression complexity for the speech signals. First of all, this work illustrated the effect of the signal length on the complexity levels of Matching Pursuit (MP) and Orthogonal Matching Pursuit (OMP) algorithms. Also, this paper introduced a study of possibility to reduce that complexity by exploiting the shared atoms among the contiguous speech compressions. By comparing the shared atoms levels and a threshold level induced by an analytic model based on the both the central and non-central hyper-geometric distributions, we proved the ability of the shared atoms criterion to detect if there is biasing towards a subspace of atoms or not, and to decide if the biasing occurs due to the redundancy in the dictionary of atoms, or due to the redundancy in the signal itself. <br />Moreover, we suggested a subspace bias-based approaches for complexity reduction called "Atoms Reuse" and "Active Cluster". Both methods exploits the higher levels of the shared atoms to reduce the compression complexity by reducing the search space during the pursuit iterations.</p>


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