scholarly journals Validation of Three-Dimensional Ray-Tracing Algorithm for Indoor Wireless Propagations

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Majdi Salem ◽  
Mahamod Ismail ◽  
Norbahiah Misran
Keyword(s):  
Ray Tracing ◽  
Electromagnetic Waves ◽  
Three Dimensional ◽  
Prediction Method ◽  
Access Point ◽  
Network Access ◽  
Multiple Reflections ◽  
Indoor Wireless ◽  
3D Ray Tracing ◽  
Tracing Algorithm

A 3D ray tracing simulator has been developed for indoor wireless networks. The simulator uses geometrical optics (GOs) to propagate the electromagnetic waves inside the buildings. The prediction technique takes into account multiple reflections and transmissions of the propagated waves. An interpolation prediction method (IPM) has been proposed to predict the propagated signal and to make the ray-tracing algorithm faster, accurate, and simple. The measurements have been achieved by using a single Wi-Fi network access point as a transmitter and a laptop as a receiver. Measured data had been collected at different positions in indoor environment and compared with predicted signals. The comparison of the predicted and measured received signals gave root mean square error of 2.96 dB and std. deviation of 2.98 dB.

scholarly journals Numerical simulation of oblique ionospheric heating by powerful radio waves

2018 ◽  
Vol 36 (3) ◽  
pp. 855-866
Author(s):  
Moran Liu ◽  
Chen Zhou ◽  
Xiang Wang ◽  
Bin Bin Ni ◽  
Zhengyu Zhao
Keyword(s):  
Ray Tracing ◽  
Electron Density ◽  
Oblique Incidence ◽  
Three Dimensional ◽  
Radio Waves ◽  
Powerful Radio ◽  
Ionospheric Electron Density ◽  
Ionospheric Heating ◽  
Tracing Algorithm ◽  
Electron Density And Temperature

<p><strong>Abstract.</strong> In this paper, we investigate the ionospheric heating by oblique incidence of powerful high-frequency (HF) radio waves using three-dimensional numerical simulations. The ionospheric electron density and temperature perturbations are examined by incorporating the ionospheric electron transport equations and ray-tracing algorithm. The energy distribution of oblique incidence heating waves in the ionosphere is calculated by the three-dimensional ray-tracing algorithm. The calculation takes into consideration the electric field of heating waves in the caustic region by the plane wave spectral integral method. The simulation results show that the ionospheric electron density and temperature can be disturbed by oblique incidence of powerful radio waves, especially in the caustic region of heating waves. The oblique ionospheric heating with wave incidence parallel and perpendicular to the geomagnetic field in the mid-latitude ionosphere is explored by simulations, results of which indicate that the ionospheric modulation is more effective when the heating wave propagates along the magnetic field line. Ionospheric density and temperature striations in the caustic region due to thermal self-focusing instability are demonstrated, as well as the time evolution of the corresponding fluctuation spectra.</p>

The appearance of the objects rolling at relativistic speeds

2008 ◽  
Vol 86 (12) ◽  
pp. 1437-1441 ◽  
Author(s):  
A Sfarti
Keyword(s):  
Ray Tracing ◽  
Three Dimensional ◽  
Line Of Sight ◽  
Rectilinear Motion ◽  
Complex Type ◽  
Computer Representation ◽  
Tracing Algorithm ◽  
Moving Bodies ◽  
Circular Outline ◽  
Relativistic Equations

In the late 1950s Terrell and Penrose produced a series of papers dealing with the appearance of the rapidly moving bodies while in rectilinear motion as photographed by a simple, pinhole camera. A few more articles on the same subject followed, for example, Penrose showed that a sphere is always seen having an exactly circular outline, at any velocity, at any distance and for any line of sight. In the present paper, we will deal with a more complex type of motion, the combination of translation and rotation that can be seen when observing the wheels of a vehicle passing by. Since Terrell and Penrose wrote their papers, great advances in the camera simulation via computer representation have been made. The field that deals with the simulation of realistic cameras via computers is called ray tracing. In the current paper, we will combine two different disciplines, relativistic physics and three-dimensional graphics to derive new results. Our paper is divided in two main parts, in the first half, we will derive the relativistic equations for rolling motion without slip and we will make some connections with the physical requirements of a relativistic ray-tracing algorithm. In the second half, we will review the foundations of classical ray-tracing algorithms and we will introduce the additional features for operation at relativistic speeds. We will demonstrate an interesting self-canceling effect of the relativistic Doppler shift on the colors wavelengths of the moving object.PACS No.: 03.30.+p

Simulation of tree point cloud based on the ray-tracing algorithm and three-dimensional tree model

2020 ◽  
Vol 200 ◽  
pp. 259-271
Author(s):  
Yaxin Li ◽  
Pei Wang ◽  
Jingqian Sun ◽  
Xiaozheng Gan
Keyword(s):  
Ray Tracing ◽  
Point Cloud ◽  
Three Dimensional ◽  
Tree Model ◽  
Tracing Algorithm

Influence of Beam Polarizations on Evaporative Laser Cutting Nonmetallic Materials within High Absorptance

2009 ◽  
Vol 626-627 ◽  
pp. 363-368
Author(s):  
Xiao Zhu Xie ◽  
J.G. Lu ◽  
Xin Wei ◽  
W. Hu
Keyword(s):  
Theoretical Analysis ◽  
Laser Beam ◽  
Ray Tracing ◽  
Laser Cutting ◽  
Three Dimensional ◽  
Coupling Model ◽  
Experimental Results ◽  
Multiple Reflections ◽  
Set Up ◽  
Tracing Method

The three dimensional (3D) coupling model is set up for analyzing the energy reflection and absorption on the kerf using ray tracing method after the laser beam cutting nonmetallic materials with high absorptance through multiple reflections. The laser beam characterized by focused gauss beam and fresnel absorption on the kerf are taken into account. The influences of the polarization on the absorbed intensity both in the front and the two walls are also discussed. Results indicate the differences of absorptive intensity among the three polarized lights are relatively small compared to metal. Thus, the polarization has little effects on the kerf of nonmetallic materials with high absorptance. The experimental results also agree well with the theoretical analysis.

scholarly journals Light propagation in firn: application to borehole video

2010 ◽  
Vol 56 (198) ◽  
pp. 614-624 ◽  
Author(s):  
T.J. Fudge ◽  
Benjamin E. Smith
Keyword(s):  
Grain Size ◽  
Ray Tracing ◽  
Light Propagation ◽  
Light Transport ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Multiple Reflections ◽  
Vertical Strain ◽  
Camera Position ◽  
Tracing Algorithm

AbstractBorehole optical stratigraphy (BOS) is a borehole video system and processing routine for investigating polar firn. BOS records brightness variations in the firn and is effective at identifying stratigraphic markers. BOS brightness logs have been used to count annual layers and measure vertical strain, even though a specific cause of the brightness variations has not been determined. Here we combine two models of light transport to examine potential errors with BOS and identify improvements which will allow the system to estimate optical grain size. We use a Monte Carlo radiative transfer model to estimate the influence of firn microstructure variations on borehole reflectance. We then use a ray-tracing algorithm to model the multiple reflections within the borehole that cause measured brightness variations. Multiple reflections cause the brightness measured at a point on the borehole wall to not necessarily be equal to the local wall reflectance. The ray tracing further shows that wall imperfections or variations in the camera position can produce brightness variations that are unrelated to changes in firn properties. Smooth walls and good stabilization of the camera help ensure that brightness variations result from variations in firn properties, and thus are a measure of firn stratigraphy, rather than artifacts.

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