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100 results on '"Ionita, Valentin"'

6. Computational Errors in Hysteresis Preisach Modelling

Author

Ionita, Valentin, Petrescu, Lucian, Bock, Hans-Georg, editor, de Hoog, Frank, editor, Friedman, Avner, editor, Gupta, Arvind, editor, Neunzert, Helmut, editor, Pulleyblank, William R., editor, Rusten, Torgeir, editor, Santosa, Fadil, editor, Tornberg, Anna-Karin, editor, Ciuprina, Gabriela, editor, and Ioan, Daniel, editor

Published
2007
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7. Secure and Efficient Exchange of Threat Information Using Blockchain Technology

Author

Pahlevan, Maryam, Ionita, Valentin, Department of Communications and Networking, Aalto-yliopisto, and Aalto University

Subjects
blockchain, threat sharing platform, TAXII standard
Abstract

Funding Information: This work was funded by the EU H2020 PHOENIX project, Contract no. 832989. Publisher Copyright: © 2022 by the authors. | openaire: EC/H2020/832989/EU//PHOENIX In recent years, sharing threat information has been one of the most suggested solutions for combating the ever-increasing number of cyberattacks, which stem from the system-wide adoption of Information and Communication Technology (ICT) and consequently endangers the digital and physical assets of organizations. Several solutions, however, were proposed to facilitate data exchange between different systems, but none were able to address the main challenges of threat sharing such as trust, privacy, interoperability, and automation in a single solution. To address these issues, this paper presents a secure and efficient threat information sharing system that leverages Trusted Automated Exchange of Intelligence Information (TAXIITM) standard and private blockchain technology to automate the threat sharing procedure while offering privacy, data integrity, and interoperability. The extensive evaluation of the solution implementation indicates its capability to offer secure communication between participants without sacrificing data privacy and overall performance as opposed to existing solutions.

Published
2022

13. Correction of measured magnetization curves using finite element method

Author

Ionita, Valentin and Cazacu, Emil

Subjects
Finite element method -- Usage, Magnetization -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

Magnetic measurement accuracy for open samples is analyzed using numerical simulations. The finite element method is used for the complete numerical correction of experimental data which are measured with a vibrating sample magnetometer. The magnetization curves are recalculated taking into account the demagnetizing field, the shape of the open magnetic circuit, and the field probe position. Index Terms--Demagnetizing factor, finite elements method (FEM), magnetic measurements, vibrating sample magnetometer (VSM).

Published
2009

16. Experimental validation of electromagnetic field computation in magnetic materials

Author

Ionita, Valentin and Cranganu-Cretu, Bogdan

Subjects
Magnetic materials -- Magnetic properties, Numerical analysis -- Usage, Business, Electronics, Electronics and electrical industries
Abstract

The local correlation between the macroscopic numerical simulations and the microscopic experimental behavior of soft magnetic materials (Fe-Si sheets) is investigated. The 2-D and 3-D magnetic field computation involves finite edge-elements and a nonlinear model of the material. The experimental investigation uses the microscopic magneto-optical imaging for thin samples of magnetic material. Index Terms--Finite-element methods, image processing, magneto-optical Kerr effect, soft magnetic material.

Published
2008

21. Object-oriented software for advanced characterization of magnetic materials

Author

Ionita, Valentin, Cranganu-Cretu, Bogdan, and Ionita, Anca

Subjects
Magnetism -- Research, Hysteresis -- Research, Business, Electronics, Electronics and electrical industries
Abstract

This paper presents a new object-oriented software, which is dedicated for the characterization of magnetic materials, including the hysteresis effect, in academic and research activities. The product allows the development and utilization of an information base containing experimental and numerical data related to the magnetic material behavior. The materials may be modeled with different hysteresis models (Preisach, Jiles-Atherton, etc.), implemented in any programming language, which allow the material advanced characterization in any electromagnetic field problem. Index Terms--Hysteresis, magnetic materials, object-oriented programming, software development.

Published
2002

23. Evaluation of magnetic material losses produced by hysteresis and eddy currents

Author

Ionita, Valentin and Preda, Gabriel

Subjects
Magnetic materials -- Analysis, Eddy currents (Electric) -- Analysis, Hysteresis -- Analysis, Electromagnetic fields -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

The paper presents a fast method for computing the quasi-stationary electromagnetic field in devices containing both magnetically nonlinear materials and hysteretic materials. The linear iterative procedure of fixed-point type allows the correct evaluation of the local field and of the losses produced by hysteresis and eddy currents. The tests are performed on a single-sheet device used to determine the magnetic material losses under the a.c. uniform field. Index Terms - Losses, hysteresis, eddy currents

Published
1998

24. Quasi-stationary magnetic field computation in hysteretic media

Author

Ionita, Valentin, Cranganu-Cretu, Bogdan, and Ioan, Daniel

Subjects
Magnetic fields -- Research, Hysteresis -- Research, Business, Electronics, Electronics and electrical industries
Abstract

This work presents a new method for analyzing quasi-stationary magnetic field in hysteretic media. The vector model of hysteresis proposed here is locally Lipschitzian and monotonous. These properties assure the convergence of the fixed-point iterative procedure. The problem is set in terms of the modified magnetic vector potential. A 2-D computation example for the impulse magnetization process of a ferromagnetic domain is given.

Published
1996

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