Electromagnetic Map Research Articles

Intelligent reconstruction algorithm of electromagnetic map based on propagation model

Intelligent reconstruction algorithm of electromagnetic map based on propagation model

Two Highly Accurate Electromagnetic Map Reconstruction Methods

An electromagnetic map (EM) can provide movable base stations with information to optimize the communication quality of temporary communication systems in disaster areas, such as areas suffering from earthquakes. In this paper, a low-cost and effective communication optimization system model that uses sensing nodes and EMs is proposed. Moreover, two EM reconstruction methods, which serve as the keys to the model, are proposed to reconstruct EMs to provide information for communication optimization according to different demands. One method is KGA-GAN-SBI, which combines the kriging algorithm, generative adversarial network and split bregman iterations, and the other is APCA-KGA-DPA, which combines the affinity propagation clustering algorithm, kriging algorithm and domain mapping algorithm. The former can satisfy the demand of high-accuracy EMs. The latter can reconstruct an EM faster than KGA-GAN-SBI. The simulation results show that both low-cost methods can reconstruct more accurate EMs than several existing algorithms; they can provide an effective way to optimize the communication quality of temporary communication and fill the gap in the study of EM applications.

An Effective Scheme of Building Electromagnetic Map for Spectrum Sensing

To address the severe spectrum scarcity problem and achieve efficient green communications, we propose a new and practical scheme to obtain electromagnetic data (ED) and a composite electromagnetic map reconstruction method (CEMRM). The scheme uses a small number of sensing nodes to obtain incomplete sampled ED, then uses CEMRM to reconstruct complete ED according to the incomplete ED and builds realistic electromagnetic maps (EMs) in various propagation scenarios. Specifically, we firstly adopt kriging (KG) method to obtain the geography-based ED (GED) according to geographical correlation of the locations of the sampled ED. Meanwhile, a novel algorithm, named filtered subdistrict sparsity adaptive matching pursuit (FSSAMP), is proposed to obtain the pure ED (PED) according to electromagnetic correlation of the sampled ED. Then, weight factors are mapped into the above two types of data and the fast gradient projection (FGP) method is employed to obtain the highly accurate combined ED (CED). Based on the CED, the accurate and practical EMs can be drawn. Simulation results demonstrate that the proposed scheme can provide more accurate ED and EMs than existing benchmark schemes in various propagation scenarios, and the built EMs can provide accurate information for the assessment of spectrum resources utilization to make spectrum resources efficiently used.

Radiofrequency radiation injures trees around mobile phone base stations

In the last two decades, the deployment of phone masts around the world has taken place and, for many years, there has been a discussion in the scientific community about the possible environmental impact from mobile phone base stations. Trees have several advantages over animals as experimental subjects and the aim of this study was to verify whether there is a connection between unusual (generally unilateral) tree damage and radiofrequency exposure. To achieve this, a detailed long-term (2006–2015) field monitoring study was performed in the cities of Bamberg and Hallstadt (Germany). During monitoring, observations and photographic recordings of unusual or unexplainable tree damage were taken, alongside the measurement of electromagnetic radiation. In 2015 measurements of RF-EMF (Radiofrequency Electromagnetic Fields) were carried out. A polygon spanning both cities was chosen as the study site, where 144 measurements of the radiofrequency of electromagnetic fields were taken at a height of 1.5m in streets and parks at different locations. By interpolation of the 144 measurement points, we were able to compile an electromagnetic map of the power flux density in Bamberg and Hallstadt. We selected 60 damaged trees, in addition to 30 randomly selected trees and 30 trees in low radiation areas (n=120) in this polygon. The measurements of all trees revealed significant differences between the damaged side facing a phone mast and the opposite side, as well as differences between the exposed side of damaged trees and all other groups of trees in both sides. Thus, we found that side differences in measured values of power flux density corresponded to side differences in damage. The 30 selected trees in low radiation areas (no visual contact to any phone mast and power flux density under 50μW/m2) showed no damage. Statistical analysis demonstrated that electromagnetic radiation from mobile phone masts is harmful for trees. These results are consistent with the fact that damage afflicted on trees by mobile phone towers usually start on one side, extending to the whole tree over time.

Measurement and mapping of the GSM-based electromagnetic pollution in the Black Sea region of Turkey

ABSTRACTElectromagnetic pollution caused by mobile communication devices, a new form of environmental pollution, has been one of the most concerning problems to date. Consequences of long-term exposure to the electromagnetic radiation caused by cell phone towers are still unknown and can potentially be a new health hazard. It is important to measure, analyze and map the electromagnetic radiation levels periodically because of the potential risks. The electromagnetic pollution maps can be used for the detection of diseases caused by the radiation. With the help of the radiation maps of different regions, comparative analysis can be provided and distribution of the diseases can be investigated. In this article, Global System for Mobile communication (GSM)-based electromagnetic pollution map of the Rize Providence, which has high cancer rates because of the Chernobyl nuclear explosion, is generated. First, locations of the GSM base stations are identified and according to the antenna types of the base stations, safety distances are determined. Subsequently, 155 measurements are taken during November 2014 from the nearest living quarters of the Rize city center in Turkey. The measurements are then assessed statistically. Thenceforth, for visual judgment of the determined statistics, collected measurements are presented on the map. It is observed that national limits are not exceeded, but it is also discovered that the safety distance is waived at some of the measurement points and above the average radiation levels are noted. Even if the national limits are not exceeded, the long-term effects of the exposition to the electromagnetic radiation can cause serious health problems.

Methodology for RF receiver sensitivity analysis using electromagnetic field map

Accurate modelling of a chip is a very important factor when analysing and predicting radio-frequency (RF) receiver sensitivity. Chip modelling based on the tangential electromagnetic (EM) field from the near-field measurement just above the top surface of the chip is introduced, and a methodology utilising three-dimensional (3D) EM simulation, for predicting receiver sensitivity generated by the chip-noise of a mobile phone, is suggested. It is worth noting here that the calculation of absolute coupling values between a noise source and an antenna is possible by using the real measured data source to obtain reliable results.

Geophysical Contribution for the Mapping the Contaminant Plume of Leachate from Rubbish Dumpsite of Hevie, Benin

In majority of the countries in the process of development like the Benin, the presence of dumpsite of rubbish can cause pollution of the groundwater. Indeed, the leachate resulting from the seepage of rain water into rubbish can infiltrate and pollute the water table. The evaluation of the infiltration of the leachate was carried out by the geophysical methods of frequential electromagnetism in EM34 and Electrical Resistivity Tomography (ERT). The electromagnetic map circumscribed the lateral limits of the leachate diffusion and the electromagnetic surveys showed that it infiltrated with a depth of 20m. The two cross sections of electrical resistivity tomography of NS and SW-NE direction made it possible to map the plume of leachate. These results show that the contact water table leachate is rather discontinuous, the depths of the feather of leachate varying from few meters to 22m for an average static level of 18m. The leachate infiltration occurs with variable depths and is not everywhere in contact with the water table. This discontinuous pollution has been observed in the water quality of the wells. Indeed, the analyses of water samples of the wells showed a great variation of heavy metal pollution in rather close wells. Research Article British Journal of Applied Science & Technology, 4(1): 127-143, 2014 128

Efficient Evaluation of EM Radiation Associated With Information Leakage From Cryptographic Devices

This paper presents an efficient map generation technique for evaluating the intensity of electromagnetic (EM) radiation associated with information leakage for cryptographic devices at the printed circuit board level. First, we investigate the relation between the intensity of the overall EM radiation and the intensity of EM information leakage on a cryptographic device. For this purpose, we prepare a map of the magnetic field on the device by using an EM scanning system, after which we perform correlation electromagnetic analysis (CEMA) at all measurement points on the device, including points above the cryptographic module. The examined device is a standard evaluation board for cryptographic modules (side-channel attack standard evaluation board), where a cryptographic circuit is implemented on one of the field-programmable gate arrays on the board. With this experiment, we demonstrate that both an EM radiation map and an information leakage map can be generated simultaneously by scanning the board only once. We also confirm that the generated map is in good agreement with the corresponding map obtained from exhaustive CEMAs.

A second-order variational principle for the Lorentz force equation: conjugacy and bifurcation

We give the notion of a conjugate instant along a solution of the relativistic Lorentz force equation (LFE). Electromagnetic conjugate instants are defined as zeros of solutions of the linearized LFE with fixed value of the charge-to-mass ratio; equivalently, we show that electromagnetic conjugate points are the critical values of the corresponding electromagnetic exponential map. We prove a second-order variational principle relating every solution of the LFE to a canonical lightlike geodesic in a Kaluza–Klein manifold, whose metric is defined using the value of the charge-to-mass ratio. Electromagnetic conjugate instants correspond to conjugate points along the lightlike geodesic, and therefore they are isolated; based on such correspondence and on a recent result of bifurcation for light rays, we prove a bifurcation result for solutions of the LFE in the exact case.

Superconducting tunnel junction as possible source of coherent photon and phonon generation

Abstract In this report pe analpse the possibilitp of utilising superconductors as active media for infrared lasers and as generators of high-Frequency coherent acoustic fields. The main problem in this direction is to obtain the inverse population in the charge-carrier spstem. Tunnel injection of electrons is one of the most promising methods to create nonepuilibrium states in superconductors. The deviation of electrons from epuilibrium changes the shape of single electron distribution function. Despite rather large observed shifts from epuilibrium, the inverse population of charge carriers in tunnel junctions is not pet registered experimentallp. After discoverp of oxide high-temperature superconductors (HTSC) nep possibilities in this field emerge. The analpsis shops that to obtain the inverse population is much more promising in HTSC, phich have anisotropic crpstalline structure and non-Debye phonon spectrum. pe present the results of theoretical investigation of non-epuilibrium distribution function both for “narrop” and for “pide” regimes of tunnel injection. pe shop that the inverse population can be obtained more easilp in the case phen the transverse Bose-fields are involved in the mechanism of Cooper pairing. In “dirtp” samples, containing sufficient amount of elastic scatterers, the inverse population map initiate the “phonon” instabilitp. Hence, the nonepuilibrium junction map serve as the generator of coherent phonon field. For crpstalline samples pith sufficientlp perfect structure the additional possibilitp emerges, because the absorption coefficient of high-Frequency electromagnetic radiation map become negative. This suggests a possibilitp to create nep family lasers: superconductor generators of far and middle range infrared radiation.