scholarly journals Local parameter identifiability of large-scale nonlinear models based on the output sensitivity covariance matrix

2021 ◽  
Vol 54 (3) ◽  
pp. 415-420
Author(s):  
Carlos S. Méndez-Blanco ◽  
Leyla Özkan
Author(s):  
Ujjal Purkayastha ◽  
Vipin Sudevan ◽  
Rajib Saha

Abstract Recently, the internal-linear-combination (ILC) method was investigated extensively in the context of reconstruction of Cosmic Microwave Background (CMB) temperature anisotropy signal using observations obtained by WMAP and Planck satellite missions. In this article, we, for the first time, apply the ILC method to reconstruct the large scale CMB E mode polarization signal, which could probe the ionization history, using simulated observations of 15 frequency CMB polarization maps of future generation Cosmic Origin Explorer (COrE) satellite mission. We find that the clean power spectra, from the usual ILC, are strongly biased due to non zero CMB-foregrounds chance correlations. In order to address the issues of bias and errors we extend and improve the usual ILC method for CMB E mode reconstruction by incorporating prior information of theoretical E mode angular power spectrum while estimating the weights for linear combination of input maps (Sudevan & Saha 2018b). Using the E mode covariance matrix effectively suppresses the CMB-foreground chance correlation power leading to an accurate reconstruction of cleaned CMB E mode map and its angular power spectrum. We compare the performance of the usual ILC and the new method over large angular scales and show that the later produces significantly statistically improved results than the former. The new E mode CMB angular power spectrum contains neither any significant negative bias at the low multipoles nor any positive foreground bias at relatively higher mutlipoles. The error estimates of the cleaned spectrum agree very well with the cosmic variance induced error.


Author(s):  
Wassim M. Haddad ◽  
Sergey G. Nersesov

This book has described a general stability analysis and control design framework for large-scale dynamical systems, with an emphasis on vector Lyapunov function methods, vector dissipativity theory, and decentralized control architectures. The large-scale dynamical systems are composed of interconnected subsystems whose relationships are often circular, giving rise to feedback interconnections. This leads to nonlinear models that can exhibit rich dynamical behavior, such as multiple equilibria, limit cycles, bifurcations, jump resonance phenomena, and chaos. The book concludes by discussing the potential for applying and extending the results across disciplines, such as economic systems, network systems, computer networks, telecommunication systems, power grid systems, and road, rail, air, and space transportation systems.


Author(s):  
Zhongjie Li ◽  
Zachary Brindak ◽  
Lei Zuo

This paper presents the modeling and analysis of an electromagnetic harvester for potential applications in large-scale vibration energy harvesting such as from vehicle suspensions or civil structures. The kinematics and dynamics of a motion mechanism and generator are considered, including backlash and friction. In this study, a dynamic model for a rack-pinion type regenerative shock absorber has been derived and analyzed based on differential equations. To understand the influence of the friction and backlash on the system, nonlinear models have been created. Simulations are carried out to study the features of the design. The validation of the models is demonstrated by comparing the simulation results with experimental measurements. Guidelines are given for the design of this type of regenerative shock absorbers.


2012 ◽  
Vol 58 (3) ◽  
pp. 285-295
Author(s):  
Diego Ernesto Cortés Udave ◽  
Jan Ogrodzki ◽  
Miguel Angel Gutiérrez De Anda

Abstract Newton-Raphson DC analysis of large-scale nonlinear circuits may be an extremely time consuming process even if sparse matrix techniques and bypassing of nonlinear models calculation are used. A slight decrease in the time required for this task may be enabled on multi-core, multithread computers if the calculation of the mathematical models for the nonlinear elements as well as the stamp management of the sparse matrix entries is managed through concurrent processes. In this paper it is shown how the numerical complexity of this problem (and thus its solution time) can be further reduced via the circuit decomposition and parallel solution of blocks taking as a departure point the Bordered-Block Diagonal (BBD) matrix structure. This BBD-parallel approach may give a considerable profit though it is strongly dependent on the system topology. This paper presents a theoretical foundation of the algorithm, its implementation, and numerical complexity analysis in virtue of practical measurements of matrix operations.


2014 ◽  
Author(s):  
Kevin Thomas Carlberg ◽  
Martin Drohmann ◽  
Raymond S. Tuminaro ◽  
Paul T. Boggs ◽  
Jaideep Ray ◽  
...  

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