International Journal of Applied Electromagnetics and Mechanics - Volume 26, issue 3-4

Authors: Micu, Dan D. | Ceclan, Andrei | Micu, Dan O. | Simion, Emil

Article Type: Research Article

Abstract: It is proposed a synthesis method of designing an inductive position sensor with Tikhonov regularization procedure. Details about the mathematical modeling and numerical solutions obtained are discussed.

Keywords: Synthesis, regularization, condition number, numerical precision, achievability

DOI: 10.3233/JAE-2007-914

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 26, no. 3-4, pp. 243-249, 2007

Authors: Lattarulo, Francesco

Article Type: Research Article

Abstract: The observed deposition, on a collector placed in the drift region outside the source, of unipolar ion flow in corona discharges is strongly dependent on the current density distribution in the ionisation sheath (source's region of support) enveloping the active electrode. Such a distribution, whose knowledge is the prerequisite for an optimal design of corona-based electrostatic devices and corona-free systems, results still undetermined. Therefore, an inverse source problem has been adopted for …reconstructing corona source features. To this end, a universal law governing the ion flow distribution in the drift region has been discovered long after an intense experimental activity. The value of the present law consists in being virtually interpretable as the boundary condition, at the source, needed for successfully resolving a forward space-charge-dominated field problem by a method based on Deutsch's hypothesis. Show more

Keywords: Corona discharge, unipolar ion flow, forward electric field problem, inverse source problem, universal boundary condition, Deutsch's hypothesis

DOI: 10.3233/JAE-2007-915

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 26, no. 3-4, pp. 251-255, 2007

Authors: Kuilekov, M. | Ziolkowski, M. | Brauer, H.

Article Type: Research Article

Abstract: The paper deals with a regularization technique applied to the reconstruction of the interface between two conducting fluids. The reconstruction is performed using a simple genetic algorithm or an evolution strategy. However, both algorithms can give ambiguous results with low cost function values and bad quality interfaces which are far away from optically observed shapes. For avoiding such situations it is implemented a regularization procedure by including in the cost function additional terms …depending on the interface parameters. The results of the new approach and the comparison with the previous one are also presented. Show more

Keywords: Inverse field problems, interface reconstruction, regularization

DOI: 10.3233/JAE-2007-916

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 26, no. 3-4, pp. 257-264, 2007

Authors: La Foresta, F. | Cacciola, M. | Mammone, N. | Morabito, F.C. | Versaci, M.

Article Type: Research Article

Abstract: It is well know that the evaluation of the bioelectric field generated by the human heart allows an accurate monitoring of the cardiac activity. In fact the human heart can be assimilated to an electric dipole that changes its amplitude and its orientation during the depolarization and repolarization processes of the heart muscle cell: this is the theoretic basis of the modern electrocardiogram (ECG). In fact the ECG is a recording of the electric potential, generated …by the electric activity of the heart, on the surface of the thorax. Thus, it is used in cardiological diagnosis, like tachycardia, arrhythmia and other disorders in the heart activation. Recent works have shown that the ECG technique could be employed to evaluate the effects of the bioelectric field generated by a fetal heart muscle in order to obtain the so-called fetal electrocardiogram (fECG). The fECG could be a very efficient way for in utero fetal heart monitoring and pathology detection during the pregnancy. In the last years many authors have studied signal processing techniques in order to obtain the fECG in a non-invasive way, but no-reflection has been shown about the bioelectric field generated by the fetal heart. The goal of this paper is to discuss the bioelectric potential distribution that the fetal heart produces on the mother abdomen during the pregnancy. The authors also show that the electrodes placement on the mother abdomen can be optimized to evaluate the fECG using blind source separation technique. Show more

Keywords: Inverse problems, ICA, fECG, bioelectromagnetic fields

DOI: 10.3233/JAE-2007-917

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 26, no. 3-4, pp. 265-271, 2007

Authors: Polak, M. | Kvitkovic, J. | Formisano, A. | Martone, R.

Article Type: Research Article

Abstract: The determination of the current distribution in full-size cable-in-conduit conductor is a relevant research activity in the framework of the International Thermonuclear Experimental Reactor, aimed at optimizing the performance of the superconducting cables to be used for the machine magnets. The direct measurement of current in the cable is not possible, and inverse techniques must be used, providing only rough estimates due to the severe ill conditioning of the problem. The measurement of magnetic field in …the neighbourhood of superconducting cables is the first step in the estimation of the current distribution inside them. Uncertainties in this early phase may very adversely impact the reliability of the problem solution. In this paper we study the impact on current reconstruction of possible errors in the measurement of magnetic field of superconducting cables of Cable in Conduit Conductor type, at low temperatures, close to 4.2 K, due to a number of physical and geometrical effects. Show more

Keywords: Magnetic field measurement, source inverse problems

DOI: 10.3233/JAE-2007-918

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 26, no. 3-4, pp. 273-283, 2007

Authors: Tomek, Jiří | Platil, Antonín | Ripka, Pavel

Article Type: Research Article

Abstract: To obtain unknown source distribution and magnetic moments of discrete magnetized ferromagnetic elementary volumes in our lung phantom we have chosen neural network inverse model. The simplified task was solved by regression multiple-layer perceptron network taught on data generated by multi-pole discrete forward model of the lungs. Magnetic fields corresponding to numerous possible sources were processed. The results are quite promising though more complex cases and especially in-vivo measurements would require much …more measuring nodes over the patient/phantom to get enough data for reasonable inversion. Show more

Keywords: Magnetopneumography, inversion, modeling, neural networks

DOI: 10.3233/JAE-2007-919

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 26, no. 3-4, pp. 285-290, 2007