Wavefront-ray grid FDTD algorithm

2016-01-01
Ciydem, Mehmet
Koç, Seyit Sencer
A finite difference time domain algorithm on a wavefront-ray grid (WRG-FDTD) is proposed in this study to reduce numerical dispersion of conventional FDTD methods. A FDTD algorithm conforming to a wavefront-ray grid can be useful to take into account anisotropy effects of numerical grids since it features directional energy flow along the rays. An explicit and second-order accurate WRG-FDTD algorithm is provided in generalized curvilinear coordinates for an inhomogeneous isotropic medium. Numerical simulations for a vertical electrical dipole have been conducted to demonstrate the benefits of the proposed method. Results have been compared with those of the spherical FDTD algorithm and it is showed that numerical grid anisotropy can be reduced highly by WRG-FDTD.
TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES

Suggestions

Open problems in CEM: A new look at the stability analysis of the finite-difference time-domain method
Ergül, Özgür Salih; Özakın, M. Burak (2014-01-01)
The stability analysis of a numerical time-domain method plays a crucial role in well understanding the numerical behavior of the algorithm. The stability analysis should therefore be investigated in all senses. In this work, a new look at the stability analysis of the Finite-Difference Time-Domain Method is given. A novel link is constructed between the numerical-dispersion analysis and the stability analysis by using the sampled values of the unit space and time steps. Unification of these two analyses th...
Consensus clustering of time series data
Yetere Kurşun, Ayça; Batmaz, İnci; İyigün, Cem; Department of Scientific Computing (2014)
In this study, we aim to develop a methodology that merges Dynamic Time Warping (DTW) and consensus clustering in a single algorithm. Mostly used time series distance measures require data to be of the same length and measure the distance between time series data mostly depends on the similarity of each coinciding data pair in time. DTW is a relatively new measure used to compare two time dependent sequences which may be out of phase or may not have the same lengths or frequencies. DTW aligns two time serie...
Numerical methods for multiphysics flow problems
Belenli Akbaş, Mine; Kaya Merdan, Songül; Rebholz, Leo G.; Department of Mathematics (2016)
In this dissertation, efficient and reliable numerical algorithms for approximating solutions of multiphysics flow problems are investigated by using numerical methods. The interaction of multiple physical processes makes the systems complex, and two fundamental difficulties arise when attempting to obtain numerical solutions of these problems: the need for algorithms that reduce the problems into smaller pieces in a stable and accurate way and for large (sometimes intractable) amount of computational resou...
Unstructured grid generation and a simple triangulation algorithm for arbitrary 2-D geometries using object oriented programming
Karamete, BK; Tokdemir, Turgut; Ger, M (Wiley, 1997-01-30)
This paper describes the logic of a dynamic algorithm for a general 2D Delaunay triangulation of arbitrarily prescribed interior and boundary nodes. The complexity of the geometry is completely arbitrary. The scheme is free of specific restrictions on the input of the geometrical data. The scheme generates triangles whose associated circumcircles contain 'no nodal points except their vertices. There is no predefined limit for the number of points and the boundaries. The direction of generation of the triang...
Time series classification with feature covariance matrices
Ergezer, Hamza; Leblebicioğlu, Mehmet Kemal (2018-06-01)
In this work, a novel approach utilizing feature covariance matrices is proposed for time series classification. In order to adapt the feature covariance matrices into time series classification problem, a feature vector is defined for each point in a time series. The feature vector comprises local and global information such as value, derivative, rank, deviation from the mean, the time index of the point and cumulative sum up to the point. Extracted feature vectors for the time instances are concatenated t...
Citation Formats
M. Ciydem and S. S. Koç, “Wavefront-ray grid FDTD algorithm,” TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES, pp. 874–881, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/35096.