Non-parametric regional VTEC modeling with Multivariate Adaptive Regression B-Splines

2011-11-01
Durmaz, Murat
Karslıoğlu, Mahmut Onur
In this work Multivariate Adaptive Regression B-Splines (BMARS) is applied to regional spatio-temporal mapping of the Vertical Total Electron Content (VTEC) using ground based Global Positioning System (GPS) observations. BMARS is a non-parametric regression technique that utilizes compactly supported tensor product B-splines as basis functions, which are automatically obtained from the observations. The algorithm uses a scale-by-scale model building strategy that searches for B-splines at each scale fitting adequately to the data and provides smoother approximations than the original Multivariate Adaptive Regression Splines (MARS). It is capable to process high dimensional problems with large amounts of data and can easily be parallelized. The real test data is collected from 32 ground based GPS stations located in North America. The results are compared numerically and visually with both the regional VTEC modeling generated via original MARS using piecewise-linear basis functions and another regional VTEC modeling based on B-splines. (C) 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.
ADVANCES IN SPACE RESEARCH

Suggestions

Short term variations of total electron content (TEC) fitting to a regional GPS network over the Kingdom of Saudi Arabia (KSA)
Alothman, A. O.; Alsubaie, M. A.; Ayhan, M. E. (Elsevier BV, 2011-09-01)
The ionosphere is a dispersive medium for radio waves with the refractive index which is a function of frequency and total electron content (TEC). TEC has a strong diurnal variation in addition to monthly, seasonal and solar cycle variations and small and large scale irregularities. Dual frequency GPS observations can be utilized to obtain TEC and investigate its spatial and temporal variations. We here studied short term TEC variations over the Kingdom of Saudi Arabia (KSA). A regional GPS network is forme...
Simulated annealing for missile optimization: Developing method and formulation techniques
Tekinalp, Ozan (American Institute of Aeronautics and Astronautics (AIAA), 2004-07-01)
Hide-and-seek is a continuous simulated annealing algorithm that uses an adaptive cooling schedule. A number of improvements are proposed for the global optimum estimation required for the cooling schedule. To handle equality constraints, two approaches are examined: the rejection method and augmentation of constraints to cost using penalty coefficients. It is demonstrated that a faster convergence is possible if, in the penalty coefficients approach, equality constraints are replaced with tight inequality ...
Nonlinear flutter calculations using finite elements in a direct Eulerian-Lagrangian formulation
Seber, Guclu; Bendiksen, Oddvar O. (American Institute of Aeronautics and Astronautics (AIAA), 2008-06-01)
A fully nonlinear aeroelastic formulation of the direct Eulerian-Lagrangian computational scheme is presented in which both structural and aerodynamic nonlinearities are treated without approximations. The method is direct in the sense that the calculations are done at the finite element level, both in the fluid and structural domains, and the fluid-structure system is time-marched as a single dynamic system using a multistage Runge-Kutta scheme. The exact nonlinear boundary condition at the fluid-structure...
Estimation of pico-satellite attitude dynamics and external torques via Unscented Kalman Filter
Söken, Halil Ersin (FapUNIFESP (SciELO), 2014-01-01)
In this study, an Unscented Kalman Filter (UKF) algorithm is designed for estimating the attitude of a picosatellite and the in-orbit external disturbance torques. The estimation vector is formed by the satellite's attitude, angular rates, and the unknown constant components of the external disturbance torques acting on the satellite. The gravity gradient torque, residual magnetic moment, sun radiation pressure and aerodynamic drag are all included in the estimated external disturbance torque vector. The sa...
Aerodynamic optimization of turbomachinery cascades using Euler/boundary-layer coupled genetic algorithms
Oksuz, O; Akmandor, IS; Kavsaoglu, MS (American Institute of Aeronautics and Astronautics (AIAA), 2002-05-01)
A new methodology is developed to find the optimal aerodynamic performance of a turbine cascade. A boundary-layer coupled Euler algorithm and a genetic algorithm are linked within an automated optimization loop. The multiparameter objective function is based on the blade loading. For a given inlet Mach number and baseline cascade geometry, the flow inlet and exit angles, the blade thickness and the solidity are optimized by a robust genetic algorithm. First, the Sanz subcritical turbine cascade is selected ...
Citation Formats
M. Durmaz and M. O. Karslıoğlu, “Non-parametric regional VTEC modeling with Multivariate Adaptive Regression B-Splines,” ADVANCES IN SPACE RESEARCH, pp. 1523–1530, 2011, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57065.