A single station ionospheric empirical model using GPS-TEC observations based on nonlinear least square estimation method

Author(s):  
Bingbing Zhang ◽  
Jiqiang Niu ◽  
Wang Li ◽  
Yi Shen ◽  
Tangting Wu ◽  
...  
2013 ◽  
Vol 13 (03n04) ◽  
pp. 319-331 ◽  
Author(s):  
Maria E. de Boyrie ◽  
Mordechai Kreinin

This article tests the effect of change in the degree of openness to import of goods and services on a country’s productivity. The idea is that by driving resources to industries in which the country has a comparative advantage, imports contribute to increased productivity in the economy. Countries from three distinct regions (OECD, Latin America and Asia), separately and together, were used to test this proposition. A feasible generalized least square estimation method is applied to determine the effect of the capital to labor ratio, openness to imports and real gross domestic product on labor productivity. A panel vector error correction model as proposed by Pesaran et al. (1999) is also performed in order to determine any causal relationship. The effect of imports on labor productivity is found to be positive and significant for the 1990–2011 period under study, strengthening the case for free trade and leading to important policy implications.


2011 ◽  
Vol 22 (01) ◽  
pp. 97-106 ◽  
Author(s):  
VINCENZO MANCA ◽  
LUCA MARCHETTI

MP systems are a class of P systems introduced for modeling metabolic processes. Here a regression method is presented for deducing a MP system exhibiting the dynamics of an observed metabolic system. In the procedure here described the knowledge of the stoichiometry of the system is combined with the log-gain principle of MP systems and is integrated with the Least Square Estimation method and with the stepwise regression approximation.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2490 ◽  
Author(s):  
Tao Lei ◽  
Weiwei Tan ◽  
Guangsi Chen ◽  
Delin Kong

This paper presents a novel Model Predictive Direct Power Control (MPDPC) approach for the pulse width modulation (PWM) rectifiers in the Aircraft Alternating Current Variable Frequency (ACVF) power system. The control performance of rectifiers may be largely affected by variations in the AC side impedance, especially for systems with limited power volume system. A novel idea for estimating the impedance variation based on the Bayesian estimation, using an algorithm embedded in MPDPC is presented in this paper. The input filter inductance and its equivalent series resistance (ESR) of PWM rectifiers are estimated in this algorithm by measuring the input current and input voltage in each cycle with the probability Bayesian estimation theory. This novel estimation method can overcome the shortcomings of traditional data based estimation methods such as least square estimation (LSE), which achieves poor estimation results with the small samples data set. In ACVF systems, the effect on the parameters estimation accuracy caused by the number of sampling points in one cycle is also analyzed in detail by simulation. The validity of this method is verified by the digital and Hard-in-loop simulation compared with other estimation methods such as the least square estimation method. The experimental testing results show that the proposed estimation algorithm can improve the robustness and the control performance of the MPDPC under the condition of the uncertainty of the AC side parameters of the three-phase PWM rectifiers in aircraft electrical power system.


2014 ◽  
Vol 117 ◽  
pp. 69-75 ◽  
Author(s):  
A. Oukaour ◽  
N. Omar ◽  
H. Gualous ◽  
A. Rachid ◽  
P. Van Den Bossche ◽  
...  

2012 ◽  
Vol 190-191 ◽  
pp. 292-296
Author(s):  
Huai Yuan Liu ◽  
Jian Hua He ◽  
Song Chen

Based on the principle of the system identification, combined Simulink with System Identification Toolbox from MATLAB, the least square estimation method is selected to establish a system of ARX model, and Akaike Information Criterion (AIC) was used in the identification of model order, compared with the original model to study the fitting accuracy, and the validity of the model is examined by residual analysis. This approach overcomes the disadvantages of the complexity and difficulty in traditional programming model. Compared to other program identification method, it has a short modeling time, and it is clear, reliable, intuitive visual, good scalability. Furthermore, the model parameters, result and system can be easily modified, assessed and verified. This method of system modeling and simulation can be used for reference to aerospace and other fields.


Mathematics ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1949
Author(s):  
Mukhtar M. Salah ◽  
M. El-Morshedy ◽  
M. S. Eliwa ◽  
Haitham M. Yousof

The extreme value theory is expanded by proposing and studying a new version of the Fréchet model. Some new bivariate type extensions using Farlie–Gumbel–Morgenstern copula, modified Farlie–Gumbel–Morgenstern copula, Clayton copula, and Renyi’s entropy copula are derived. After a quick study for its properties, different non-Bayesian estimation methods under uncensored schemes are considered, such as the maximum likelihood estimation method, Anderson–Darling estimation method, ordinary least square estimation method, Cramér–von-Mises estimation method, weighted least square estimation method, left-tail Anderson–Darling estimation method, and right-tail Anderson–Darling estimation method. Numerical simulations were performed for comparing the estimation methods using different sample sizes for three different combinations of parameters. The Barzilai–Borwein algorithm was employed via a simulation study. Three applications were presented for measuring the flexibility and the importance of the new model for comparing the competitive distributions under the uncensored scheme. Using the approach of the Bagdonavicius–Nikulin goodness-of-fit test for validation under the right censored data, we propose a modified chi-square goodness-of-fit test for the new model. The modified goodness-of-fit statistic test was applied for the right censored real data set, called leukemia free-survival times for autologous transplants. Based on the maximum likelihood estimators on initial data, the modified goodness-of-fit test recovered the loss in information while the grouping data and followed chi-square distributions. All elements of the modified goodness-of-fit criteria tests are explicitly derived and given.


Radio Science ◽  
2017 ◽  
Vol 52 (2) ◽  
pp. 196-214 ◽  
Author(s):  
Jiandi Feng ◽  
Zhengtao Wang ◽  
Weiping Jiang ◽  
Zhenzhen Zhao ◽  
Bingbing Zhang

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