A Novel Optimized V-VLC Receiver Sensor Design Using μGA in Automotive Applications

Vehicular visible light communication is known as a promising way of inter-vehicle communication. Vehicular VLC can ensure the significant advancement of safety and efficiency in traffic. It has disadvantages, such as unexpected glare on drivers in moving conditions, i.e., non-line-of-sight link at night. While designing a receiver, the most important factor is to ensure the optimal quality of the received signal. Within this context, to achieve an optimal communication quality, it is necessary to find the optimal maximum signal strength. Hereafter, a new receiver design is focused on in this paper at the circuit level, and a novel micro genetic algorithm is proposed to optimize the signal strength. The receiver can calculate the SNR, and it is possible to modify its structural design. The micro GA determines the alignment of the maximum signal strength at the receiver point rather than monitoring the signal strength for each angle. The results showed that the proposed scheme accurately estimates the alignment of the receiver, which gives the optimum signal strength. In comparison with the conventional GA, the micro GA results showed that the maximum received signal strength was improved by −1.7 dBm, −2.6 dBm for user Location 1 and user Location 2, respectively, which proves that the micro GA is more efficient. The execution time of the conventional GA was 7.1 s, while the micro GA showed 0.7 s. Furthermore, at a low SNR, the receiver showed robust communication for automotive applications.

MATRIX SIMULATOR OF ECHO SIGNALS OF TWO-POSITION RADAR STATION

In this paper echo signals simulation task of two-position systems was considered. A matrix simulator composed of coherent transmitters is offered as a solution. Herewith in order to provide independent imitation for each antenna of the Radar station it’s suggested to use the additional transmitters correcting simulated echo signals at the receiving points. Correction is based on the principle of phase compensation of the signals from emitters that are equidistant from a specific receiver point. The configuration of the minimum possible number of emitting points was obtained, which has the potential for independent control of the apparent radiation center. Shown that the compensation condition of the signals of the transmitter group is not enough for independent control of the apparent radiation center. The sufficient independence conditions were formulated. The obtained theoretical results were confirmed by the data of numerical experiments.

Multichannel analysis of Love waves in a 3D seismic acquisition system

Multichannel analysis of Love waves (MALW) analyzes high-frequency Love waves to determine near-surface S-wave velocities, and it is getting increasing attention in the near-surface geophysics and geotechnique community. Based on 2D geometry spread, in which sources and receivers are placed along the same line, current MALW fails to work in a 3D seismic acquisition system. This is because Love-wave particle motion direction is perpendicular to its propagation direction, which makes it difficult to record a Love-wave signal in 3D geometries. We have developed a method to perform MALW with data acquired in 3D geometry. We recorded two orthogonal horizontal components (inline and crossline components) at each receiver point at the same time. By transforming the raw data from rectangular coordinates (inline and crossline components) to radial-transverse coordinates (radial and transverse components), we recovered Love-wave data along the transverse direction at each receiver point. To achieve a Love-wave dispersion curve, the recovered Love-wave data were first transformed into a conventional receiver offset domain, and then transformed into the frequency-velocity ([Formula: see text]-[Formula: see text]) domain. Love-wave dispersion curves were picked along the continuous dispersive energy peaks in the [Formula: see text]-[Formula: see text] domain. The validity of our proposed method was verified by two synthetic tests and a real-world example.

The optimum orientation of an absorbing barrier

In the following work, we solve the problem of the best orientation of a rigid noise barrier, which has one face lined with absorbent material, between a noise source and a receiver point in the shadow region of the barrier. By the ‘best orientation’, we mean that positioning of the barrier which yields the least noise level at the receiving point for a given barrier and source position.

An Aerodynamic Noise Propagation Model for Wind Turbines

A model based on 2-D sound ray theory for aerodynamic noise propagation from wind turbine rotating blades is introduced. The model includes attenuation factors from geometric spreading, sound directivity of source, air absorption, ground deflection and reflection, as well as effects from temperature and airflow. At a given receiver point, the sound pressure is corrected by taking into account these propagation effects. As an overall assumption, the noise field generated by the wind turbine is simplified as a point source placed at the hub height of the wind turbine. This assumtion is reasonable, for the receiver is located in the far field, at distances from the wind turbine that are much longer than the diameter of the rotor.

On unified dual fields and Einstein deconvolution

In many physical phenomena, the laws governing motion can be looked at as the relationship between unified dual fields which are continuous in time and space. Both fields are activated by a single source. The most notable example of such phenomena is electromagnetism, in which the dual fields are the electric field and the magnetic field. Another example is acoustics, in which the dual fields are the particle‐velocity field and the pressure field. The two fields are activated by the same source and satisfy two first‐order partial differential equations, such as those obtained by Newton’s laws or Maxwell’s equations. These equations are symmetrical in time and space, i.e., they obey the same wave equation, which differs only in the interface condition changing sign. The generalization of the Einstein velocity addition equation to a layered system explains how multiple reflections are generated. This result shows how dual sensors at a receiver point at depth provide the information required for a new deconvolution method. This method is called Einstein deconvolution in honor of Albert Einstein. Einstein deconvolution requires measurements of the pressure signal, the particle velocity signal, and the rock impedance, all at the receiver point. From these measurements, the downgoing and upgoing waves at the receiver are computed. Einstein deconvolution is the process of deconvolving the upgoing wave by the downgoing wave. Knowledge of the source signature is not required. Einstein deconvolution removes the unknown source signature and strips off the effects of all the layers above the receiver point. Specifically, the output of Einstein deconvolution is the unit‐impulse reflection response of the layers below the receiver point. Compared with the field data, the unit‐impulse reflection response gives a much clearer picture of the deep horizons, a desirable result in all remote detection problems. In addition, the unit‐impulse reflection response is precisely the input required to perform dynamic deconvolution. Dynamic deconvolution yields the reflectivity (i.e., reflection‐ coefficient series) of the interfaces below the receiver point. Alternatively, predictive deconvolution can be used instead of dynamic deconvolution.

Reply by the author to R. Ignetik

The failure of Ignetik to recognize the logic underlying my approach to polygonal‐loop modeling demonstrates a need to present some points more clearly. The starting point was that I wanted to represent the transmitter as an array of vertical magnetic dipoles rather than horizontal linear dipoles. The reason for this was to minimize the computation needed for downhole receivers and multiple transmitter loops. The layered‐earth Green’s tensor elements for horizontal linear dipoles for a general “receiver” point are very complicated for the N‐layer case. Those for the vertical dipole are very simple and require much less computation.

Quadratic wavefront and traveltime approximations in inhomogeneous layered media with curved interfaces

A quadratic approximation for the square of the traveltime from a source region to a receiver region is given for a three‐dimensional (3-D) medium consisting of inhomogeneous layers with curved interfaces. The square of the traveltime, being a function of source and receiver coordinates, is developed in a Taylor series around a reference source and receiver point. The relationships of the traveltime parameters to the ray parameters and the wavefront curvature matrices are shown. Using midpoint, half‐offset coordinates gives a simplified traveltime function compared to using source‐receiver coordinates only in the case that the reference source point and the reference receiver point coincide (zero‐offset approximation). For a medium consisting of homogeneous layers with plane dipping interfaces, the traveltime approximation is further simplified. The derived traveltime approximation is shown to be exact for a reflection from a plane dipping interface in a homogeneous medium. Explicit expressions for the traveltime parameters in terms of the layer parameters are derived for a horizontally layered medium. The traveltime errors of two different approximations are compared for a given layered model in a numerical example.