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Ivanenko, Yevhen
Publications (10 of 18) Show all publications
Ivanenko, Y., Custafsson, M., Jonsson, B. L., Luger, A., Nilsson, B., Nordebo, S. & Toft, J. (2019). Passive Approximation and Optimization Using B-Splines. SIAM Journal on Applied Mathematics, 79(1), 436-458
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2019 (English)In: SIAM Journal on Applied Mathematics, ISSN 0036-1399, E-ISSN 1095-712X, Vol. 79, no 1, p. 436-458Article in journal (Refereed) Published
Abstract [en]

A passive approximation problem is formulated where the target function is an arbitrary complex-valued continuous function defined on an approximation domain consisting of a finite union of closed and bounded intervals on the real axis. The norm used is a weighted L-p-norm where 1 <= p <= infinity. The approximating functions are Herglotz functions generated by a measure with Holder continuous density in an arbitrary neighborhood of the approximation domain. Hence, the imaginary and the real parts of the approximating functions are Holder continuous functions given by the density of the measure and its Hilbert transform, respectively. In practice, it is useful to employ finite B-spline expansions to represent the generating measure. The corresponding approximation problem can then be posed as a finite-dimensional convex optimization problem which is amenable for numerical solution. A constructive proof is given here showing that the convex cone of approximating functions generated by finite uniform B-spline expansions of fixed arbitrary order (linear, quadratic, cubic, etc.) is dense in the convex cone of Herglotz functions which are locally Holder continuous in a neighborhood of the approximation domain, as mentioned above. As an illustration, typical physical application examples are included regarding the passive approximation and optimization of a linear system having metamaterial characteristics, as well as passive realization of optimal absorption of a dielectric small sphere over a finite bandwidth.

Keywords
approximation, Herglotz functions, B-splines, passive systems, convex optimization, sum rules
National Category
Mathematics
Research subject
Mathematics, Applied Mathematics
Identifiers
urn:nbn:se:lnu:diva-81228 (URN)10.1137/17M1161026 (DOI)000460127100021 ()
Available from: 2019-03-22 Created: 2019-03-22 Last updated: 2019-03-22Bibliographically approved
Ivanenko, Y. & Nordebo, S. (2019). Passive Approximation with High-Order B-Splines. In: Karl‐Olof Lindahl, Torsten Lindström, Luigi G. Rodino, Joachim Toft, Patrik Wahlberg (Ed.), Analysis, Probability, Applications, and Computation: Proceedings of the 11th ISAAC Congress, Växjö (Sweden) 2017 (pp. 83-94). Springer
Open this publication in new window or tab >>Passive Approximation with High-Order B-Splines
2019 (English)In: Analysis, Probability, Applications, and Computation: Proceedings of the 11th ISAAC Congress, Växjö (Sweden) 2017 / [ed] Karl‐Olof Lindahl, Torsten Lindström, Luigi G. Rodino, Joachim Toft, Patrik Wahlberg, Springer, 2019, p. 83-94Conference paper (Refereed)
Abstract [en]

Convex optimization has emerged as a well-suited tool for passive approximation. Here, it is desired to approximate some pre-defined non-trivial system response over a given finite frequency band by using a passive system. This paper summarizes some explicit results concerning the Hilbert transform of general B-splines of arbitrary order and arbitrary partitions that can be useful with the convex optimization formulation. A numerical example in power engineering is included concerning the identification of some model parameters based on measurements on high-voltage insulation materials.

Place, publisher, year, edition, pages
Springer, 2019
Series
Trends in Mathematics
Identifiers
urn:nbn:se:lnu:diva-82770 (URN)10.1007/978-3-030-04459-6_8 (DOI)2-s2.0-85065446429 (Scopus ID)
Available from: 2019-05-27 Created: 2019-05-27 Last updated: 2019-05-27
Nordebo, S., Gustafsson, M., Ivanenko, Y., Nilsson, B. & Sjöberg, D. (2018). Cylindrical multipole expansion for periodic sources with applications for three-phase power cables. Mathematical methods in the applied sciences, 41(3), 959-965
Open this publication in new window or tab >>Cylindrical multipole expansion for periodic sources with applications for three-phase power cables
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2018 (English)In: Mathematical methods in the applied sciences, ISSN 0170-4214, E-ISSN 1099-1476, Vol. 41, no 3, p. 959-965Article in journal (Refereed) Published
Abstract [en]

This paper presents a c ylindrical multipole expansion for periodic sources with applications for three-phase power cables.It is the aim of the contribution to provide some analytical solutions and techniques that can be useful in the calculation ofcable losses. Explicit analytical results are given for the fields generated by a three-phase helical current distribution andwhich can be computed efficiently as an input to other numerical methods such as, for example , the Method of Moments.It is shown that the field computations are numerically stable at low frequencies (such as 50 Hz) as well as in the quasi-magnetostatic limit provided that sources are divergence-free. The cylindrical multipole expansion is fur thermore usedto derive an efficient analytical model of a measurement coil to measure and estimate the complex valued permeability ofmagnetic steel armour in the presence of a strong skin-effect.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2018
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Signal Processing
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-59497 (URN)10.1002/mma.3992 (DOI)000425834700011 ()
Available from: 2016-12-23 Created: 2016-12-23 Last updated: 2018-03-09Bibliographically approved
Ivanenko, Y., Dalarsson, M., Nordebo, S. & Bayford, R. (2018). On the plasmonic resonances in a layered waveguide structure. In: 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials): . Paper presented at 12th International Congress on Artificial Materials for Novel Wave Phenomena-Metamaterials, 27 Aug.-1 Sept. 2018, Espoo, Finland (pp. 188-190). IEEE
Open this publication in new window or tab >>On the plasmonic resonances in a layered waveguide structure
2018 (English)In: 2018 12th International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials), IEEE, 2018, p. 188-190Conference paper, Published paper (Refereed)
Abstract [en]

An optimal plasmonic resonance and the associated Fröhlich resonance frequency are derived for a thin layer in a straight waveguide in TM mode. The layer consists of an arbitrary composite material with a Drude type of dispersion. The reflection and transmission coefficients of the layer are analyzed in detail. To gain insight into the behavior of a thin plasmonic layer, an asymptotic expansion to the first order is derived with respect to the layer permittivity.

Place, publisher, year, edition, pages
IEEE, 2018
National Category
Other Physics Topics
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-82120 (URN)10.1109/MetaMaterials.2018.8534151 (DOI)978-1-5386-4703-5 (ISBN)978-1-5386-4702-8 (ISBN)978-1-5386-4701-1 (ISBN)
Conference
12th International Congress on Artificial Materials for Novel Wave Phenomena-Metamaterials, 27 Aug.-1 Sept. 2018, Espoo, Finland
Available from: 2019-04-24 Created: 2019-04-24 Last updated: 2019-05-07Bibliographically approved
Ivanenko, Y., Nedic, M., Gustafsson, M., Jonsson, B. L., Luger, A. & Nordebo, S. (2018). Quasi-Herglotz functions and convex optimization.
Open this publication in new window or tab >>Quasi-Herglotz functions and convex optimization
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2018 (English)Report (Other academic)
Abstract [en]

We introduce the set of quasi-Herglotz functions and demonstrate that it has properties useful in the modeling of non-passive systems. The linear space of quasi-Herglotz functions constitutes a natural extension of the convex cone of Herglotz functions. It consists of differences of Herglotz functions, and we show that several of the important properties and modeling perspectives of Herglotz functions are inherited by the new set of quasi-Herglotz functions. In particular, this applies to their integral representations, the associated integral identities or sum rules (with adequate additional assumptions), their boundary values on the real axis and the associated approximation theory. Numerical examples are included to demonstrate the modeling of a non-passive gain media formulated as a convex optimization problem,where the generating measure is modeled by using a finite expansion of B-splines and point masses.

Publisher
p. 24
Keywords
Quasi-Herglotz functions, non-passive systems, approximation, convex optimization, sum rules
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Other Mathematics
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-78933 (URN)
Funder
Swedish Foundation for Strategic Research , AM13-0011
Available from: 2018-11-22 Created: 2018-11-22 Last updated: 2018-11-26Bibliographically approved
Ivanenko, Y. (2017). Estimation of electromagnetic material properties with application to high-voltage power cables. (Licentiate dissertation). Linnaeus University Press
Open this publication in new window or tab >>Estimation of electromagnetic material properties with application to high-voltage power cables
2017 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Efficient design of high-voltage power cables is important to achieve an economical delivery of electric power from wind farms and power plants over the very long distances as well as the overseas electric power. The main focus of this thesis is the investigation of electromagnetic losses in components of high-voltage power cables. The objective of the ongoing research is to develop the theory and optimization techniques as tools to make material choices and geometry designs to minimize the high-frequency attenuation and dispersion for HVDC power cables and the power losses associated with HVAC cables. Physical limitations, dispersion relationships and the application of sum rules as well as convex optimization will be investigated to obtain adequate physical insight and a priori modeling information for these problems.

For HVAC power cables, the objectives are addressed by performing measurements and estimation of complex valued permeability of cable armour steel in Papers I and II. Efficient analytical solutions for the electromagnetic field generated by helical structures with applications for HVAC power cables have been obtained in Paper III.

For HVDC power cables, estimation of insulation characteristics from dielectric spectroscopy data using Herglotz functions, convex optimization and B-splines, has been investigated in Papers V and VI. The unique solution requirements in waveguide problems have been reviewed in Paper IV.

Place, publisher, year, edition, pages
Linnaeus University Press, 2017. p. 19
Series
Lnu Licentiate ; 2
Keywords
Material losses, power cables, cylindrical multipole expansion, Herglotz functions, convex optimization, sum rules
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-64265 (URN)978-91-88357-77-9 (ISBN)
Presentation
2017-06-14, C1202, Newton, Hus C, Växjö, 10:15 (English)
Opponent
Supervisors
Funder
Swedish Foundation for Strategic Research , AM13-0011
Available from: 2017-06-09 Created: 2017-06-09 Last updated: 2017-09-01Bibliographically approved
Nordebo, S., Dalarsson, M., Ivanenko, Y., Sjöberg, D. & Bayford, R. (2017). On the physical limitations for radio frequency absorption in gold nanoparticle suspensions. Journal of Physics D: Applied Physics, 50(15), Article ID 155401.
Open this publication in new window or tab >>On the physical limitations for radio frequency absorption in gold nanoparticle suspensions
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2017 (English)In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 50, no 15, article id 155401Article in journal (Refereed) Published
Abstract [en]

This paper presents a study of the physical limitations for radio frequency absorption in gold nanoparticle (GNP) suspensions. A spherical geometry is considered consisting of a spherical suspension of colloidal GNPs characterized as an arbitrary passive dielectric material which is immersed in an arbitrary lossy medium. A relative heating coefficient and a corresponding optimal near field excitation are defined, taking the skin effect of the surrounding medium into account. The classical Mie theory for lossy media is also revisited, and it is shown that the optimal permittivity function yielding a maximal absorption inside the spherical suspension is a conjugate match with respect to the surrounding lossy material. A convex optimization approach is used to investigate the broadband realizability of an arbitrary passive material to approximate the desired conjugate match over a finite bandwidth, similar to the approximation of a metamaterial. A narrowband realizability study shows that for a surrounding medium consisting of a weak electrolyte solution, the electromagnetic heating, due to the electrophoretic (plasmonic) resonance phenomena inside the spherical GNP suspension, can be significant in the microwave regime, provided that the related Drude parameters can be tuned into (or near to) resonance. As a demonstration, some realistic Drude parameters are investigated concerning the volume fraction, mass, and friction constant of the GNPs. The amount of charge that can be accommodated by the GNPs is identified as one of the most important design parameters. However, the problem of reliably modelling, measuring and controlling the charge number of coated GNPs is not yet fully understood, and is still an open research issue in this field. The presented theory and related physical limitations provide a useful framework for further research in this direction. Future research is also aimed at an expansion towards arbitrary suspension geometries and the inclusion of thermodynamical analysis.

National Category
Signal Processing
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-65659 (URN)10.1088/1361-6463/aa5a89 (DOI)
Available from: 2017-06-20 Created: 2017-06-20 Last updated: 2017-06-28Bibliographically approved
Nordebo, S., Dalarsson, M., Ivanenko, Y., Sjöberg, D. & Bayford, R. (2017). Parameter studies on optimal absorption and electrophoretic resonances in lossy media. In: 32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017: . Paper presented at 32nd URSI General Assembly & Scientific Symposium, Montreal, Canada, 19-26 August 2017 (pp. 1768-1769). IEEE
Open this publication in new window or tab >>Parameter studies on optimal absorption and electrophoretic resonances in lossy media
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2017 (English)In: 32nd General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2017, IEEE, 2017, p. 1768-1769Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
IEEE, 2017
National Category
Other Physics Topics
Research subject
Physics, Electrotechnology
Identifiers
urn:nbn:se:lnu:diva-82122 (URN)10.23919/URSIGASS.2017.8105294 (DOI)000463723600344 ()978-1-5090-4469-6 (ISBN)978-90-825987-0-4 (ISBN)978-90-825987-1-1 (ISBN)
Conference
32nd URSI General Assembly & Scientific Symposium, Montreal, Canada, 19-26 August 2017
Available from: 2019-04-24 Created: 2019-04-24 Last updated: 2019-05-27Bibliographically approved
Ivanenko, Y., Gustafsson, M., Jonsson, B., Luger, A., Nilsson, B., Nordebo, S. & Toft, J. (2017). Passive approximation and optimization with B-splines.
Open this publication in new window or tab >>Passive approximation and optimization with B-splines
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2017 (English)Report (Other academic)
Abstract [en]

A passive approximation problem is formulated where the target function is an arbitrary complex valued continuous function defined on an approximation domain consisting of a closed interval of the real axis. The approximating function is any Herglotz function with a generating measure that is absolutely continuous with Hölder continuous density in an arbitrary neighborhood of the approximation domain. The norm used is induced by any of the standard Lp-norms where 1 ≤ p ≤ ∞. The problem of interest is to study the convergence properties of simple Herglotz functions where the generating measures are given by finite B-spline expansions, and where the real part of the approximating functions are obtained via the Hilbert transform. In practice, such approximations are readily obtained as the solution to a finite- dimensional convex optimization problem. A constructive convergence proof is given in the case with linear B-splines, which is valid for all Lp-norms with 1 ≤ p ≤ ∞. A number of useful analytical expressions are provided regarding general B-splines and their Hilbert transforms. A typical physical application example is given regarding the passive approximation of a linear system having metamaterial characteristics. Finally, the flexibility of the optimization approach is illustrated with an example concerning the estimation of dielectric material parameters based on given dispersion data. 

Publisher
p. 24
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-63878 (URN)
Funder
Swedish Foundation for Strategic Research , AM13-0011
Available from: 2017-05-18 Created: 2017-05-18 Last updated: 2017-06-09Bibliographically approved
Ivanenko, Y. & Nordebo, S. (2017). Passive approximation and optimization with B-splines. In: 2nd URSI GASS, Montreal, 19–26 August 2017: . Paper presented at 32nd URSI General Assembly & Scientific Symposium, 19-26 August, 2017, Montreal (pp. 2290-2293). URSI
Open this publication in new window or tab >>Passive approximation and optimization with B-splines
2017 (English)In: 2nd URSI GASS, Montreal, 19–26 August 2017, URSI , 2017, p. 2290-2293Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
URSI, 2017
National Category
Other Physics Topics
Research subject
Physics, Waves and Signals
Identifiers
urn:nbn:se:lnu:diva-82121 (URN)
Conference
32nd URSI General Assembly & Scientific Symposium, 19-26 August, 2017, Montreal
Note

Ej belagd 190507

Available from: 2019-04-24 Created: 2019-04-24 Last updated: 2019-05-07Bibliographically approved
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