scholarly journals Autofocus Entropy Repositioning Method Bioinspired in the Magnetic Field Memory of the Bees Applied to Pollination

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6198
Author(s):  
Daniel de Matos Luna dos Santos ◽  
Ewaldo Eder Carvalho Santana ◽  
Paulo Fernandes da Silva Junior ◽  
Jonathan Araujo Queiroz ◽  
João Viana da Fonseca Neto ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Feature Extraction ◽  
Real Time ◽  
Unsupervised Method ◽  
Color Characteristics ◽  
Magnetic Declination ◽  
Positioning Method ◽  
The Magnetic Field ◽  
Robust Response

In this paper, a bioinspired method in the magnetic field memory of the bees, applied in a rover of precision pollination, is presented. The method calculates sharpness features by entropy and variance of the Laplacian of images segmented by color in the HSV system in real-time. A complementary positioning method based on area feature extraction between active markers was developed, analyzing color characteristics, noise, and vibrations of the probe in time and frequency, through the lateral image of the probe. From the observed results, it can be seen that the unsupervised method does not require previous calibration of target dimensions, histogram, and distances involved in positioning. The algorithm showed less sensitivity in the extraction of sharpness characteristics regarding the number of edges and greater sensitivity to the gradient, allowing unforeseen operation scenarios, even in small sharpness variations, and robust response to variance local, temporal, and geophysical of the magnetic declination, not needing luminosity after scanning, with the two freedom of degrees of the rotation.

scholarly journals Location Fingerprint Extraction for Magnetic Field Magnitude Based Indoor Positioning

2016 ◽  
Vol 2016 ◽  
pp. 1-16 ◽  
Author(s):  
Wenhua Shao ◽  
Fang Zhao ◽  
Cong Wang ◽  
Haiyong Luo ◽  
Tunio Muhammad Zahid ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Feature Extraction ◽  
Measurement Technique ◽  
Extraction Methods ◽  
Indoor Positioning ◽  
Coarse Grained ◽  
Electronic Noise ◽  
Magnetic Field Magnitude ◽  
Positioning Method ◽  
The Magnetic Field

Smartphone based indoor positioning has greatly helped people in finding their positions in complex and unfamiliar buildings. One popular positioning method is by utilizing indoor magnetic field, because this feature is stable and infrastructure-free. In this method, the magnetometer embedded on the smartphone measures indoor magnetic field and queries its position. However, the environments of the magnetometer are rather harsh. This harshness mainly consists of coarse-grained hard/soft-iron calibrations and sensor electronic noise. The two kinds of interferences decrease the position distinguishability of the magnetic field. Therefore, it is important to extract location features from magnetic fields to reduce these interferences. This paper analyzes the main interference sources of the magnetometer embedded on the smartphone. In addition, we present a feature distinguishability measurement technique to evaluate the performance of different feature extraction methods. Experiments revealed that selected fingerprints will improve position distinguishability.

scholarly journals Noninvasive muscle activity imaging using magnetography

2020 ◽  
Vol 117 (9) ◽  
pp. 4942-4947 ◽  
Author(s):  
Rodolfo R. Llinás ◽  
Mikhail Ustinin ◽  
Stanislav Rykunov ◽  
Kerry D. Walton ◽  
Guilherme M. Rabello ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Contrast Media ◽  
Electrical Activity ◽  
Real Time ◽  
Human Body ◽  
Muscle Activity ◽  
Muscular Activity ◽  
Exponential Increase ◽  
Somatic Musculature ◽  
The Magnetic Field

A spectroscopic paradigm has been developed that allows the magnetic field emissions generated by the electrical activity in the human body to be imaged in real time. The growing significance of imaging modalities in biology is evident by the almost exponential increase of their use in research, from the molecular to the ecological level. The method of analysis described here allows totally noninvasive imaging of muscular activity (heart, somatic musculature). Such imaging can be obtained without additional methodological steps such as the use of contrast media.

scholarly journals Athanasius Kircher and Terrestrial Magnetism: The Magnetic Map

2020 ◽  
Vol 7 (2) ◽  
pp. 166-184
Author(s):  
Agustín Udías, S.J.
Keyword(s):  
Magnetic Field ◽  
Terrestrial Magnetism ◽  
The Earth ◽  
Magnetic Declination ◽  
Athanasius Kircher ◽  
Different Sources ◽  
The Magnetic Field

Athanasius Kircher paid special attention to magnetism, more specifically terrestrial one, in his work Magnes sive de arte magnetica. Other Jesuits of his time, such as Garzoni and Cabeo, also wrote on this subject. Kircher studied in particular magnetic declination and its possible use to determine geographical longitudes. At his time, this was an important subject for long sea journeys. First, he collected a large number of observations of magnetic declination from different sources in three tables and two lists with a total of 518 values, among them forty-three made by Jesuits. Kircher proposed that a magnetic map could be made based on these observations, but he did not do it. From Kircher’s observations a map of magnetic declination has been drawn and it is presented here. Kircher discussed the causes of declination and presented a model for the origin of the magnetic field of the Earth, which differed from that proposed by Gilbert. Kircher finally considered magnetism as a cosmic force with its origin in God.

The long-term optical activity of the propellers AE Aquarii and AR Scorpii

2020 ◽  
Vol 72 (2) ◽  
Author(s):  
Vojtěch Šimon
Keyword(s):  
Magnetic Field ◽  
Real Time ◽  
Optical Activity ◽  
White Dwarf ◽  
Transient Decrease ◽  
Mass Outflow ◽  
Orbital Modulation ◽  
The Magnetic Field

Abstract This analysis of the long-term optical activity of the propellers AE Aqr and AR Sco uses data from the Catalina Real-time Transient Survey, DASCH, and AAVSO. The site and character of the emissions from the phenomena caused by the magnetic field of the white dwarf (WD) vary from system to system. The histogram of intensities of the ensemble of flares of AE Aqr suggests that the long-term activity consists of a large variety of the peak magnitudes of the flares, with the probability of their detection gradually decreasing with increasing intensity. Any increase of activity only leads to an increase of the number of blobs of the transferring matter. We also detected a season with a transient decrease or even a cessation of the mass outflow from the donor to the lobe of the WD. The very strong orbital modulation of AR Sco is most stable in the phases of the extrema of brightness for about a century; its minor changes suggest that the trailing side of the synchrotron-emitting region is more unstable than the leading side.

scholarly journals Indoor Positioning Using Magnetic Fingerprint Map Captured by Magnetic Sensor Array

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5707
Author(s):  
Ching-Han Chen ◽  
Pi-Wei Chen ◽  
Pi-Jhong Chen ◽  
Tzung-Hsin Liu
Keyword(s):  
Magnetic Field ◽  
Sensor Array ◽  
Probabilistic Neural Network ◽  
Indoor Positioning ◽  
Magnetic Sensor ◽  
Magnetic Sensors ◽  
Positioning System ◽  
Positioning Accuracy ◽  
Positioning Method ◽  
The Magnetic Field

By collecting the magnetic field information of each spatial point, we can build a magnetic field fingerprint map. When the user is positioning, the magnetic field measured by the sensor is matched with the magnetic field fingerprint map to identify the user’s location. However, since the magnetic field is easily affected by external magnetic fields and magnetic storms, which can lead to “local temporal-spatial variation”, it is difficult to construct a stable and accurate magnetic field fingerprint map for indoor positioning. This research proposes a new magnetic indoor positioning method, which combines a magnetic sensor array composed of three magnetic sensors and a recurrent probabilistic neural network (RPNN) to realize a high-precision indoor positioning system. The magnetic sensor array can detect subtle magnetic anomalies and spatial variations to improve the stability and accuracy of magnetic field fingerprint maps, and the RPNN model is built for recognizing magnetic field fingerprint. We implement an embedded magnetic sensor array positioning system, which is evaluated in an experimental environment. Our method can reduce the noise caused by the spatial-temporal variation of the magnetic field, thus greatly improving the indoor positioning accuracy, reaching an average positioning accuracy of 0.78 m.

scholarly journals MHD simulation of flare situation above the active region AR 10365 in the real time scale.

2020 ◽  
Author(s):  
A.I. Podgorny ◽  
◽  
I.M. Podgorny ◽  
A.V. Borisenko ◽  
◽  
...  
Keyword(s):  
Magnetic Field ◽  
Active Region ◽  
Real Time ◽  
Time Scale ◽  
Rapid Change ◽  
Field Configuration ◽  
Mhd Simulation ◽  
The Real ◽  
Real Time Scale ◽  
The Magnetic Field

Since the configuration of the magnetic field in the corona, where solar flares appear, cannot be determined from observations, to study the flare situation, a numerical magnetohydrodynamic (MHD) simulation is carried out above the active region. MHD simulation performed in a greatly reduced (10 000 times) time scale permit to obtain results on the study of the solar flare mechanism, but the magnetic field configuration was distorted, especially near the photospheric boundary, due to the unnaturally rapid change in the field on the photosphere. For a more accurate study of the flare situation, MHD simulation in the real time scale was performed above the active region of AR 10365, which was made possible through the use of parallel calculations. The MHD simulation in the real scale of time above the AR 10365 during the first day of evolution showed the appearance of current density maxima with singular X-type line and plasma flow, which have to cause to the formation of a current sheet.

scholarly journals Real-time 3-D hybrid simulation of Titan's plasma interaction during a solar wind excursion

2009 ◽  
Vol 27 (9) ◽  
pp. 3349-3365 ◽  
Author(s):  
S. Simon
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Real Time ◽  
Plasma Flow ◽  
Time Scale ◽  
Hybrid Simulation ◽  
The Moon ◽  
Plasma Interaction ◽  
Plasma Environment ◽  
The Magnetic Field

Abstract. The plasma environment of Saturn's largest satellite Titan is known to be highly variable. Since Titan's orbit is located within the outer magnetosphere of Saturn, the moon can leave the region dominated by the magnetic field of its parent body in times of high solar wind dynamic pressure and interact with the thermalized magnetosheath plasma or even with the unshocked solar wind. By applying a three-dimensional hybrid simulation code (kinetic description of ions, fluid electrons), we study in real-time the transition that Titan's plasma environment undergoes when the moon leaves Saturn's magnetosphere and enters the supermagnetosonic solar wind. In the simulation, the transition between both plasma regimes is mimicked by a reversal of the magnetic field direction as well as a change in the composition and temperature of the impinging plasma flow. When the satellite enters the solar wind, the magnetic draping pattern in its vicinity is reconfigured due to reconnection, with the characteristic time scale of this process being determined by the convection of the field lines in the undisturbed plasma flow at the flanks of the interaction region. The build-up of a bow shock ahead of Titan takes place on a typical time scale of a few minutes as well. We also analyze the erosion of the newly formed shock front upstream of Titan that commences when the moon re-enters the submagnetosonic plasma regime of Saturn's magnetosphere. Although the model presented here is far from governing the full complexity of Titan's plasma interaction during a solar wind excursion, the simulation provides important insights into general plasma-physical processes associated with such a disruptive change of the upstream flow conditions.

Elaboration d'une stratigraphie paleomagnetique des formations volcaniques

1963 ◽  
Vol S7-V (2) ◽  
pp. 182-187
Author(s):  
A. Roche
Keyword(s):  
Magnetic Field ◽  
Western Europe ◽  
Rock Magnetism ◽  
The West ◽  
Complex Curve ◽  
Geologic Time ◽  
Magnetic Declination ◽  
Magnetic Inclination ◽  
The Magnetic Field ◽  
Method Show

Abstract From the analysis of the natural magnetism of rocks, a component--thermoremanent magnetism (T. R. M.)--can be isolated, which corresponds to the magnetism acquired by the rocks at the time of their formation. Results of observations based on the method show that the earth's magnetic field resembles the field created by a geocentric dipole, the axis of which, as related to the earth's crust, has changed considerably throughout geologic time. The intensity of the field has also varied although it is not certain to what degree. Observation of the nature and direction of the rock magnetism shows that the trajectory of the geomagnetic axis, in the course of time, corresponds to a complex curve with numerous reversals and points of intersection. Figures for the declination and inclination of the magnetic field obtained from Precambrian to Quaternary rocks of France and other areas of western Europe indicate that magnetic inclination during the Silurian and Devonian and the Permian and Triassic was slight; that magnetic declination was more often to the east than to the west; and that in the Permian, Triassic and Cretaceous variations in direction were of little importance and reversals were numerous, while in the Carboniferous and Neogene there was considerable variation in direction with fewer reversals.

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