Institute annual report 2021

(updated: January 5, 2024; June 28, 2023, December 3, 2022, with Peer reviews)

Human resources

The Numerical Analysis and Approximation Theory workgroup:

• Prof. Dr. Radu Precup, m.c. (hired in 2021)
• Dr. Emil Cătinaş (workgroup coordinator)
• Prof. Dr. Octavian Agratini
• Dr. Diana Otrocol
• Dr. Flavius Pătrulescu (till April 28)
• Dr. Mihai Nechita
• Imre Boros
• Dr. Cristian-Daniel Alecsa (till February 25)
• Andrei Stan (hired in 2021)

The Numerical Modeling workgroup:

• Dr. Călin-Ioan Gheorghiu (workgroup coordinator)
• Dr. rer. nat. habil. Nicolae Suciu
• Dr. Maria Crăciun

PhD students/postdocs

PhD students:

• Cristian-Daniel Alecsa, Optimization. A dynamical systems approach, at UT Cluj (till February 2021)
• Imre Boros, Numerical methods for partial differential equations, at UBB Cluj
• Andrei Stan, Nash type equilibria for systems of nonlinear equations, at UBB Cluj

Postdocs:

• Mihai Nechita, at INRIA, France

PhD advisors

Prof. Dr. Radu Precup, corresponding member of the Romanian Academy, supervises PhD theses at Babeş-Bolyai University.
PhD students (2021):

• Andrei Stan, Nash type equilibria for systems of nonlinear equations
• Alexandru Hofman, Control problems for systems of Kolmogorov type
• David Brumar, The analysis of some mathematical models in fluid dynamics.

Prof. dr. Octavian Agratini, supervises PhD theses at Babeş-Bolyai University.
theses supervised 2021:

• Grapini O. Silviu-Ilie,
• Balogh M. Anamaria,
• Bunea-Domșa S. Mihai Grigore,
• Boros Imre, Numerical methods for partial differential equations.

Dr. rer. nat. habil. Nicolae Suciu supervises PhD theses.
He has recently supervised the thesis Filtered density functions for uncertainty assessment of transport in groundwater, by Lennart Schüler, defended on September 8, 2016, at Jena University, Germany; the thesis received the distinction Magna Cum Laudae.

Prof. dr. Ion Păvăloiu, honorary member, has supervised -in the past- 8 PhD theses at North University of Baia-Mare and at Babeş-Bolyai University.

Complete information on PhD coordination may be found on the webpage.

Publications of the Institute members

Books

• M. Nechita, Unique continuation problems and stabilised finite element methods, Casa Cărții de Știință, Cluj-Napoca, Romania, 124 pp., ISBN: 978-606-17-1816-0

Volumes edited

• Nonlinear Functional Analysis and Its Applications, R. Precup (editor), MDPI, Basel, ISBN 978-3-0365-0240-3 (Hbk), ISBN 978-3-0365-0241-0 (PDF), https://mdpi-res.com/bookfiles/book/3589/Nonlinear_Functional_Analysis_and_Its_Applications.pdf?v=1705502970

Papers published in JCR/ISI indexed journals:

Papers in JCR journals from abroad

• E. Cătinaş, How many steps still left to x*?, SIAM Rev. 63 (2021) no. 3, pp. 585–624 (Impact Factor 2020: 10.7, SRI: 9.8)
• N. Suciu, D. Illiano, A. Prechtel, F.A.Radu, Global random walk solvers for fully coupled flow and transport in saturated/unsaturated porous media, Adv. Water Res., 152 (2021), 103935, https://doi.org/10.1016/j.advwatres.2021.103935 (IF 4.5, SRI 2.4)
• O. Agratini, S.G. Gal,  On Landau-type approximation operators, Mediterr. J. Math., 18 (2021) art. no. 64, https://doi.org/10.1007/s00009-021-01712-w (IF 1.4, SRI 0.7)
• O. Agratini, Approximation properties of a family of integral type operators, Positivity, 25 (2021), 97–108, https://doi.org/10.1007/s11117-020-00752-y (IF 1.0, SRI 0.6)
• O. Agratini, A. Aral, Approximation of some classes of functions by Landau type operators, Results Math., 76 (2021) art. no. 12, doi: 10.1007/s00025-020-01319-9 (IF 1.1, SRI 0.7)
• U. Abel, O. Agratini, On the Durrmeyer-type variant and generalizations of Lototsky-Bernstein operators, Symmetry, 13 (2021) no. 10, art. no. 1841, https://doi.org/10.3390/sym13101841 (IF 2.7, SRI 0.5)
• A. Viorel, C.D. Alecsa, T.O. Pinţa, Asymptotic analysis of a structure-preserving integrator for damped Hamiltonian systems, Discrete & Continuous Dynamical Systems, 41 (2021) 7, 3319-3341, doi: 10.3934/dcds.2020407 (IF 1.3, SRI 1.4)
• C.D. Alecsa, S.C. László, T. Pinţa, An extension of the second order dynamical system that models Nesterov’s convex gradient method, Appl. Math. Optim., 84 (2021), pp. 1687–1716. doi: 10.1007/s00245-020-09692-1 (IF 3.5, SRI 2.1)
• I.S. Haplea, L.G. Parajdi, R. Precup, On the controllability of a system modeling cell dynamics related to leukemia, Symmetry, 13 (2021), art. id. 1867, https://doi.org/10.3390/sym13101867 (17 pp.) (IF 2.7, SRI 0.5)
• C.I. Gheorghiu, Accurate spectral collocation computations of high order eigenvalues for singular Schrödinger equations-revisited, Symmetry, 13 (2021) 5, https://doi.org/10.3390/sym13050761 (IF 2.7, SRI 0.5)
  
• C.I. Gheorghiu, Accurate spectral collocation solutions to 2nd-order Sturm–Liouville problems, Symmetry, 13 (2021), art. id. 385, doi: 10.3390/sym13030385 (IF 2.7, SRI 0.5)
• A. Novac, D. Otrocol, D. Popa, Ulam stability of a linear difference equation in locally convex spaces, Results Math., 76, 33 (2021). https://doi.org/10.1007/s00025-021-01344-2 (IF 1.1, SRI 0.7)
• V. Ilea, D. Otrocol, On a Volterra integral equation with delay, via w-distances, Mathematics 9 (2021), art. id. 2341, 8 pp., https://doi.org/10.3390/math9182341 (IF 2.2, SRI 0.5)
• C.D. Alecsa, L.S. Csaba, Tikhonov regularization of a perturbed heavy ball system with vanishing damping, SIAM J. Optim., 31 (2021) no. 4, pp. 2921-2954, http://doi.org/10.1137/20M1382027 (IF 1.4, SRI 3.6)
• R. Precup, J. Rodríguez-López, A unified variational approach to discontinuous differential equations, Mediterr. J. Math. 18 (2021) art. no. 62, 14 pp., https://doi.org/10.1007/s00009-021-01705-9
• R. Precup, P. Rubbioni, Stationary solutions of Fokker-Planck equations with nonlinear reaction terms in bounded domains, Potential Analysis, 57 (2022), 181–199, https://doi.org/10.1007/s11118-021-09911-6
• L.G. Parajdi, R. Precup, M.-A. Serban, I.S. Haplea, Analysis of the effectiveness of the treatment of solid tumors in two cases of drug administration, Mathematical Biosciences and Engineering, 18 (2021) no. 2, 1845-1863.
• R. Precup, Componentwise localization of critical points for functionals defined on product spaces, Topological Methods in Nonlinear Analysis 58 (2021), No. 1, 51-77.
• I. Benedetti, T. Cardinali, R. Precup, Fixed point-critical point hybrid theorems and application to systems with partial variational structure, Journal of Fixed Point Theory and Applications 23, 63 (2021), 1-19. https://doi.org/10.1007/s11784-021-00852-6 (IF 2.11)

Papers in JCR journals from Romania

• O. Agratini, O. Dogru, Kantorovich-type operators associated with a variant of Jain operators, Stud. Univ. Babes-Bolyai Math. 66 (2021) no. 2, 279–288, doi: 10.24193/subbmath.2021.2.04 (JCI 0.39)
• V. Ilea, D. Otrocol, Functional differential equations with maxima, via step by step contraction principle, Carpathian J. Math., 37 (2021) no. 2, pp. 195-202, DOI: 10.37193/CJM.2021.02.05 (IF 1.7, SRI 0.6)
• H. Boulaiki, T. Moussaoui, R. Precup, Positive solutions for second-order differential equations of Kirchhoff type on the half-line, Carpathian J. Math. 37 (2021), No. 2., 325-338. (IF 1.7)

Chapters in books

• N. Suciu, Global Random Walk Solutions for Flow and Transport in Porous Media, in: F.J. Vermolen, C. Vuik (eds.), Numerical Mathematics and Advanced Applications ENUMATH 2019, Lecture Notes in Computational Science and Engineering, vol 139. Springer, Cham, pp. 939-947, doi: https://doi.org/10.1007/978-3-030-55874-1_93
• S. Koumla, R. Precup, Study on integrodifferential evolution systems with nonlocal initial conditions, Recent Advances in Mathematical Research and Computer Science, vol. 5 2021, pp. 13-27, https://doi.org/10.9734/bpi/ramrcs/v5/3535F
• R. Lopez Pouso, R. Precup, J. Rodrıguez-Lopez, Positive Solutions for Discontinuous Systems via a Multivalued Vector Version of Krasnoselskii’s Fixed Point Theorem in Cones, in: Nonlinear Functional Analysis and Its Applications (editor R. Precup), MDPI, Basel, 2021, pp. 45-59.

Papers published in other journals

• C. I. Gheorghiu, Accurate spectral collocation computation of high order eigenvalues for singular Schrödinger equations, Computation, 9 (2021) 2, 19 pp. https://doi.org/10.3390/computation9010002

Preprints in Arxiv

• N. Suciu, F.A. Radu, Global random walk solvers for reactive transport and biodegradation processes in heterogeneous porous media, Arxiv: 2107.08745, 2021, https://arxiv.org/pdf/2107.08745.pdf
• C. I. Gheorghiu, Accurate spectral collocation solutions to some Bratu’s type Boundary Value Problems, arXiv:2011.13212

Papers accepted

• I. Păvăloiu, E. Cătinaş, A new optimal method of order four of Hermite-Steffensen type, Mediterranean Journal of Mathematics, to appear in 2022.

Papers submitted

• N. Suciu, F.A. Radu, Global random walk solvers for reactive transport and biodegradation processes in heterogeneous porous media, Arxiv: 2107.08745, 2021, https://arxiv.org/pdf/2107.08745.pdf, submitted to Advances in Water Resources (17.07.2021), under review.
• A. Pop, M. Crăciun, Detection and detectability: evidence for a low amplitude orbital period modulation in the Algol-type binary U Coronae Borealis, submitted to Acta Astronomica, under review.
• M. Nechita, On high-order conforming finite element methods for ill-posed Helmholtz problems.
• R. Precup, C.-I. Gheorghiu, Theory and computation of radial solutions for Neumann problems with φ-Laplacian, submitted.

Prizes, outstanding achievements

• N. Suciu, the “Spiru Haret” prize of the Romanian Academy, for the monograph Diffusion in Random Fields. Application to Transport in Groundwater, Springer/Birkhauser, 2019.
• E. Cătinaş, CNCSIS prize for a paper published in the journal ranked first in “Applied Mathematics”: How many steps still left to x*?, SIAM Rev. 63 (2021) no. 3, pp. 585–624 (Impact Factor 2020: 10.7, SRI: 9.8) (code PRECISI-2021-55599)

CNCSIS prizes for papers published in the “red zone” journals (based on journals impact factor or influence score):

2. N. Suciu, code PRECISI-2021-62584.
3. R. Precup, code PRECISI-2021-66832
4. R. Precup, code PRECISI-2021-62454
5. D. Otrocol, code PRECISI-2021-89830

CNCSIS prizes for papers published in the “yellow zone” journals:

6. R. Precup, code PRECISI-2021-64695
7. O. Agratini, code PRECISI-2021-58968
8. O. Agratini, code PRECISI-2021-58986
9. O. Agratini, code PRECISI-2021-55727
10. O. Agratini, code PRECISI-2021-67188
11. C.I. Gheorghiu, code PRECISI-2021- 63782
12. C.I. Gheorghiu, code PRECISI-2021- 63786
13. C.D. Alecsa, code PRECISI-2021- 58531
14. C.D. Alecsa, code PRECISI-2021-55746
15. D. Otrocol, code PRECISI-2021-91847
16. D. Otrocol, code PRECISI-2021-90784

Prof. Dr. R. Precup has H-index 14: https://publons.com/researcher/499454/radu-precup/

Dr. rer. nat. habil. N. Suciu has H-index 13: https://publons.com/researcher/2061433/nicolae-suciu/

Prof. dr. O. Agratini has H-index 9: https://publons.com/researcher/??

Editorial activity

• Fixed Point Theory and Algorithms for Sciences and Engineering (Springer), R. Precup (Section Editor);
• Studia UBB Math.: R. Precup (Editor-in-Chief), O. Agratini (senior Editor)
• Carpathian Journal of Mathematics, R. Precup (Member of the Editorial Board);
• J. Numer. Anal. Approx. Theory: O. Agratini (Editor-in-Chief), E. Cătinaş (Editor-in-Chief), I. Păvăloiu (deputy Editor-in-Chief), D. Otrocol, M. Nechita, I. Boros
• Fixed Point Theory (Cluj), R. Precup (Deputy Editor-in-Chief);
• Proceedings of the Romanian Academy- Series A, R. Precup (Member of the Editorial Board);
• ROMAI Journal: N. Suciu, C.I. Gheorghiu
• Mathematica (Cluj): R. Precup, O. Agratini
• Discussiones Mathematicae Differential Inclusions, Control and Optimization (Poland), R. Precup (Member of the Editorial Board);
• Open Journal of Discrete Mathematics: O. Agratini
• Mathematics in Engineering, Science and Aerospace (USA), R. Precup (Member of the Board);
• J. Science and Arts: O. Agratini
• Transylvanian Journal of Mathematics and Mechanics (Romania), R. Precup (Member of the Board);
• Journal of Inequalities and Special Functions (Poland), R. Precup (Member of the Editorial Board);

Conferences organized

• 70 years from the foundation of the „Tiberiu Popoviciu” Institute of Numerical Analysis, October 28, 2021.

Conferences attended by the members of the Institute

Conferences from abroad

• Suciu, N, Iliano, D., Prechtel, A., Radu, F.A., Global random walk solvers for fully coupled flow and transport in saturated/unsaturated porous media, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1941, https://doi.org/10.5194/egusphere-egu21-1941.
• Suciu, N., Radu, F.A., Global random walk solvers for flow and multi-component reactive transport in heterogeneous porous media, InterPore2021 Online Conference, July 2021, http://dx.doi.org/1010.13140/RG.2.2.36165.58084
• O. Agratini, International Conference “Recent Developments in Mathematical Analysis”, Bari, Italy, September 22–23, 2021, https://www.dm.uniba.it/ricerca/convegni/2021/redima.
• A. Pop, M. Crăciun and M. Barbosu, Light Travel Time Effect – from Fourier parameters to orbital elements through different approaches, Viewpoints in Astronomy, Astrophysics, Space and Planetary Sciences, International Conference 28-29 October 2021, Cluj Academic Days 2021.
• M. Nechita, Unique continuation problems and stabilised finite element methods, Control in times of crisis, seminar online, 21.01.2021. http://ctcseminar.mat.utfsm.cl/index-2020-2021.html
• M. Nechita, Finite element regularization for convection-dominated data assimilation problems, 29th IFIP TC7 Conference on system modelling and optimization, 02.09.2021, https://modemat.epn.edu.ec/ifip_tc7_2021/files/book_of_abstracts.pdf
• D. Otrocol, V. Ilea, Functional differential equations with maxima, via step by step contraction principle, Approximation Theory and Applications (MS – ID 78), 8th European Congress of Mathematics, Portoroz, Slovenia, 20-26 iunie 2021,6https://8ecm.si/system/admin/abstracts/pdfs/000/002/032/original/diana-otrocol.pdf?1620802238

Conferences from Romania

• E. Cătinaş, Ordine de convergenţă, comparaţii asimptotice, metode iterative elementare, Conferinţa Cercetării Științifice din Academia Română (CCSAR-2021), 22-23 noiembrie 2021, https://acad.ro/com2021/doc/docCCSAR/CCSAR-Program-Ziua2-Panel3-vf.pdf.
• N. Suciu, Metode de tip “random walk” pentru transport reactiv în medii poroase – avantaje și limitări, Conferinţa Cercetării Științifice din Academia Română (CCSAR-2021), 22-23 noiembrie 2021, https://acad.ro/com2021/doc/docCCSAR/CCSAR-Program-Ziua2-Panel3-vf.pdf.
• M. Nechita, Probleme dominate de convecție: regularizarea asimilării datelor folosind elemente finite, Conferinţa Cercetării Științifice din Academia Română (CCSAR-2021), 22-23 noiembrie 2021, https://acad.ro/com2021/doc/docCCSAR/CCSAR-Program-Ziua2-Panel3-vf.pdf.

The following talks have been given at the symposium 70 years from the foundation of the „Tiberiu Popoviciu” Institute of Numerical Analysis (October 28, 2021)

• O. Agratini, On Landau-type approximation operators.
• E. Cătinaş, How many steps still left to x*?
• N. Suciu, F.A. Radu, Random walk methods for coupled flow and reactive transport in porous media.
• C.-I. Gheorghiu, On the efficiency of Chebfun system in solving genuinely nonlinear BVPs.
• D. Otrocol, Differential equations with maxima, via step by step contraction principle.
• M. Crăciun, A. Pop, ESC method as a tool for differential diagnosis of variability phenomena: periodicity versus quasi-periodicity.
• I. Boros, An overview of spectral collocation methods which are modified to work in arbitrary precision.
• M. Nechita, Unique continuation problems and stabilised finite element methods.
• E. Cătinaş, A. Stan, On the convergence orders.

Membership in professional organizations

• E. Cătinaş, SIAM member
• ??, (to be completed)

Grants

• International grant SU 415/4-1 (https://gepris.dfg.de/gepris/projekt/405338726) obtained by dr. rer. habil. N. Suciu from (Deutschefourschungs Gmemeindschaft), for the project “Integrated global random walk model for reactive transport in groundwater adapted to measurement spatio-temporal scales” (01.10.2018-30.09.2021), at Erlangen-Nuernberg University.

Peer review

Members of PhD supervising committees

• R. Precup, for Florin Albișoru (supervisor: M. Kohr)
• R. Precup, for Ioan Papuc (supervisor: M. Kohr)
• R. Precup, for Andra Manu (supervisor: M. Kohr)
• R. Precup, for Mădălina Moga (supervisor: A. Petrusel)
• O. Agratini, for Fodor Valerian Alin (supervisor Pintea Cornel)
• O. Agratini, for thesis Metode de aproximare a functiilor de mai multe variabile, by Malina Andra (supervisor T. Cătinaș)
• O. Agratini, for Șuțu Mădălina (supervisor T. Cătinaș)

Referee reports for peer reviewed journals

• O. Agratini, for: Studia Universitatis Babeș-Bolyai Mathematica (3), Journal of Numerical Analysis and Approximation Theory (2), Constructive Mathematical Analysis (1), Mathematica Slovaca (2), Applicable Analysis and Discrete Mathematics (1), Numerical Functional Analysis and Optimization (1), Filomat (1), Mathematical Foundations of Computing (1), Hacettepe Journal of Mathematics & Statistics (1), Quaestiones Mathematicae (1)
• C.I. Gheorghiu (to be completed)

Paper reviews

for Mathematical Reviews:

• R. Precup: MR4308919, MR4246912
• O. Agratini: MR4373047, MR4265455
• C. Mustăța: MR4300978, MR4293609, MR4223891, MR4180098
• D. Otrocol: MR4279663

for ZBL:

• C.I. Gheorghiu: Zbl 1482.65199, 1476.76050, 1484.76042, 1472.65140, 1472.65138, 1477.65197, 1472.65141, 1472.65146, 1477.65249, 1467.65114, 1468.76038, 1468.76043, 1469.76064, 1467.65095, 1464.65234, 1464.76063, 1477.65007, 1492.76080, 1464.76053, 1460.65127, 1461.76344, 1464.65185, 1464.76055

(to be completed)