Geomagnetically induced currents (GICs) in technological conductor systems are a manifestation of the ground effects of space weather. Large GICs are always associated with large values of the time derivative of the geomagnetic field, and especially with its horizontal component (dH/dt). By using the IMAGE magnetometer data from northern Europe from 1982 to 2001, we show that large dH/dt’s (exc...

an_eul is a new automatic method for simultaneous approximation of location, depth, and structural index (geometry) of magnetic sources. in the 2d case analytic signal is defined as a conjugate function whose imaginary part is the hilbert transform of its real part. since the first vertical derivative of the magnetic field is the hilbert transform of its horizontal derivative, vertical and hori...

in this article, we survey the asymptotic stability analysis of fractional differential systems with the prabhakar fractional derivatives. we present the stability regions for these types of fractional differential systems. a brief comparison with the stability aspects of fractional differential systems in the sense of riemann-liouville fractional derivatives is also given.

in this paper, we prove the existence and uniqueness results to the random fractional functional differential equations under assumptions more general than the lipschitz type condition. moreover, the distance between exact solution and appropriate solution, and the existence extremal solution of the problem is also considered.

We study certain generalized Leray-alpha magnetohydrodynamics systems. We show that the solution pairs of velocity and magnetic fields to this system in two-dimension preserve their initial regularity in two cases: dissipation logarithmically weaker than a full Laplacian and zero diffusion, zero dissipation and diffusion logarithmically weaker than a full Laplacian. These results extend previou...

The low frequency electric signals (emitted from the focal area when the stress reaches a critical value) that precede major earthquakes, are recorded at distances approximately 100 km being accompanied by magnetic field variations. The electric field "arrives" 1 to 2 s before the time derivative of the horizontal magnetic field. An explanation, which is still awaiting, should consider, beyond ...

This paper presents the development and validation of a vision-based navigation and control system for a small unmanned quadrotor. The core of this system is a state estimator based on the so-called multi-camera parallel tracking and mapping algorithm, which provides accurate pose estimation for the quadrotor using multiple cameras. Built on cascaded proportional-integral-derivative control loo...

This paper is devoted to the determination of the origin point in forest fires propagation using a control algorithm. The forest fires propagation are mathematically modelled starting from a reaction diffusion model. A V.O.F. formulation is also used to determine the fraction of the area which is burnt. After having developed the objective functional and its derivative, results from an optimiza...

The multiscale analysis of potential fields is a valid tool to study the source properties. Among multiscale methods, the Continuous Wavelet Transform (CWT) is well established due to its natural filtering properties. From the beginning the choice of the analyzing wavelet has been the set belonging to the Poisson kernel: within this framework the CWT can be easily performed by upward continuing...