scholarly journals Coupled Harmonic Admittance Identification Based on Least Square Estimation

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2600 ◽  
Author(s):  
Yaqiong Li ◽  
Zhanfeng Deng ◽  
Tongxun Wang ◽  
Guoliang Zhao ◽  
Shengjun Zhou
Keyword(s):  
Equivalent Circuit ◽  
Time Domain ◽  
Field Data ◽  
Mutual Coupling ◽  
Least Square ◽  
Estimation Technique ◽  
Least Square Estimation ◽  
Harmonic Current ◽  
Emission Estimation ◽  
Current Emission

Norton equivalent circuit is a commonly used model in estimating harmonic current emissions of harmonic sources. It however cannot reflect the mutual coupling relationships among voltage and current in different harmonic orders. This paper proposes a new method to identify parameters in a coupled harmonic admittance model. The proposed method is conducted using voltage and current measurements and is based on least square estimation technique. The effectiveness of the method is verified through time-domain simulations for a grid-connected converter and also through field data obtained from a ±800 kV converter station. The experimental results showed that the proposed method presents higher accuracy in terms of harmonic current emission estimation compared with three Norton-base methods.

A Technique Based on Kalman Filter and Least Square Estimation for Time Domain Structural Damage Detection

2010 ◽  
Vol 163-167 ◽  
pp. 2683-2688 ◽  
Author(s):  
Ying Lei ◽  
Yi Ke Mao
Keyword(s):  
Kalman Filter ◽  
Damage Detection ◽  
Time Domain ◽  
Structural Damage ◽  
Least Square ◽  
Unknown Input ◽  
Dynamic Parameters ◽  
Structural Damage Detection ◽  
Least Square Estimation ◽  
Structural Dynamic

In this paper, a time domain structural damage detection approach based on Kalman filter and least square estimation is proposed for structures under limited input and output measurements. First of all, the dynamic parameters of the structure, such as stiffness and damping coefficients are identified by sequentially utilizing the extended Kalman estimator and the least squares estimation. Secondly, after the structural dynamic parameters are gained, the normal Kalman filter and least square estimation is used to identify the state vector and unknown input of the structure, and the changes of the structure such as reducing of the stiffness are regarded as ‘additional unknown input’. Then the changed parameters can be calculated by analyses the connection between ‘additional unknown input’ and changing parameters, Local structural damage in the structure can also be detected by tracking the changes in the identified values of structural dynamic parameters in time domain at element level, e.g., the degrading of stiffness parameters. Numerical example of detecting structural local damages in a four story share building illustrates the efficiency of the proposed approach.

scholarly journals Workers' Remittances and Growth Linkages in Pakistan

2016 ◽  
Vol 2 (2) ◽  
pp. 81-92
Author(s):  
Fouzia Yasmin ◽  
Muhammad Zahir Faridi ◽  
Hina Ali ◽  
Adnan Yasin
Keyword(s):  
Time Series ◽  
Data Analysis ◽  
Time Series Data ◽  
Developed Countries ◽  
Least Square ◽  
Series Data ◽  
Estimation Technique ◽  
Least Square Estimation ◽  
Ordinary Least Square ◽  
The Right

Remittances are considered as the cash inflows to the economy and are imperative international source of revenue for most of the less developed countries (LDCs). For data analysis, the Ordinary least square estimation technique was employed to the time series data for the years 1981 to 2010. This research comes with the conclusion that level of GDP is positively associated with the worker's remittances and the findings also support the optimistic view of remittances. It is suggested that govt. should take serious steps and proper measures to utilize the workers' remittances so, that the economy will be on the right track towards the development.  

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