# Institute annual report 2020

updates: January 9, 2024; June 28, 2023 (with Peer Review), December 3, 2022; March 15, 2022 (on CNCSIS prizes for papers).

updates: January 9, 2024; June 28, 2023 (with Peer Review), December 3, 2022; March 15, 2022 (on CNCSIS prizes for papers).

The Numerical Analysis and Approximation Theory workgroup:

- Dr. Emil
**Cătinaş**(workgroup coordinator) - Prof. Dr. Octavian
**Agratini** - Dr. Diana
**Otrocol** - Dr. Flavius
**Pătrulescu** - Dr. Mihai
**Nechita** - Imre
**Boros** - Dr. Cristian-Daniel
**Alecsa**

The Numerical Modeling workgroup:

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

PhD students:

- Cristian-Daniel
**Alecsa**,*Optimization. A dynamical systems approach,*at UT Cluj (since October 2020) – supervisor: S.C. László - Imre
**Boros**,*Numerical methods for partial differential equations,*at UBB Cluj – supervisor: O. Agratini - Mihai
**Nechita**, at University College London (till September 2020) – supervisors: Erik Burman and Lauri Oksanen

Postdocs:

- Mihai
**Nechita**, at INRIA Paris (since October 2020)

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.

Prof. dr. Octavian **Agratini**, supervised PhD theses at Babes-Bolyai University.

theses supervised 2020:

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

- C.D. Alecsa, I. Boros, F. Frank, P. Knabner, M. Nechita, A. Prechtel, A. Rupp, N. Suciu,
*Numerical benchmark study for flow in highly heterogeneous aquifers*, Adv. Water Res., 138 (2020), 103558. Impact Factor (IF) 2019:**4.01** - C.D. Alecsa, T. Pinţa, I. Boros,
*New optimization algorithms for neural network training using operator splitting techniques*, Neural Networks, 126 (2020), 178-190. doi: 10.1016/j.neunet.2020.03.018 IF 2019:**5.53** - E. Burman, M. Nechita, L. Oksanen,
*A stabilized finite element method for inverse problems subject to the convection-diffusion equation. I: diffusion-dominated regime*, Numer. Math. 144 (2020), pp. 451-477 IF 2019:**2.05** - M. Crăciun, T. Harko,
*Testing Bose-Einstein condensate dark matter models with the SPARC galactic rotation curves data*, The European Physical Journal C, 80 (2020) 8, 735, 1-28,**IF 2019: 4.3** - C.-D. Alecsa, S.C. László, A. Viorel,
*A gradient-type algorithm with backward inertial steps associated to a nonconvex minimization problem*, Numer. Algor. 84 (2020), pp. 485-512. - F. Pătrulescu, T. Groşan, I. Pop,
*Natural convection from a vertical plate embedded in a non-Darcy bidisperse porous medium*, ASME-Journal of Heat Transfer 142(1): 012504, HT-19-1097 (2020), (11 pages) - V. Ilea, A. Novac, D. Otrocol, R. Precup,
*Solutions with a prescribed interval of positivity for differential systems with nonlocal conditions*, Appl. Math. Comput., 375 (2020), doi: 10.1016/j.amc.2020.125092 - V. Ilea, D. Otrocol,
*Existence and uniqueness of the solution for an integral equation with supremum, via w-distances*, Symmetry 2020, 12, 1554, https://doi.org/10.3390/sym12091554 - O. Agratini,
*Linear positive operators constructed by using Beta-type bases*, Hacettepe Journal of Mathematics & Statistics, 49 (2020) no. 3, pp. 1030-1038, doi: 10.15672/hujms.549015 - C.I. Gheorghiu,
*Spectral collocation based on quasi-classical orthogonal polynomials applied to solve a singular BVP from hydrodynamics*, AIP Conference Proceedings 2293, 100004 (2020); doi: 10.1063/5.0026783 - A.M. Acu, A. Măduța, D. Otrocol, I. Raşa,
*Inequalities for information potentials and entropies*, Mathematics 2020, 8(11), 2056; doi: 10.3390/math8112056

- O. Agratini,
*Modifying an approximation process using non-Newtonian calculus*, Stud. Univ. Babes-Bolyai Math. 65 (2020) no. 2, 291–301, doi: 10.24193/subbmath.2020.2.10 - V. Ilea, D. Otrocol,
*On the Burton method of progressive contractions for Volterra integral equations*, Fixed Point Theory, 21 (2020) no. 2, 585-594.

- T. Cătinaș, D. Otrocol,
*Iterates of Cheney-Sharma type operators on a triangle with curved side*, J. Comp. Anal. Appl., 28 (2020) no. 4, pp. 737-744. - O. Agratini,
*A stop over Jain operators and their generalizations*, Annals of West University of Timisoara – Mathematics and Computer Science, 56 (2018) no. 2, pp. 28-42.

- C. I. Gheorghiu,
*Accurate spectral collocation computation of high order eigenvalues for singular Schroedinger equations.*arXiv/3486226[math-ph] - C. I. Gheorghiu,
*Accurate spectral collocation solutions to some Bratu’s type Boundary Value Problems*. arXiv/3486209[math.NA] - C. I. Gheorghiu,
*Spectral collocation solutions to second order singular Sturm-Liouville eigenproblems*, arXiv/ 3484569[math.NA] - C.D. Alecsa, I. Boros, F. Frank, P. Knabner, M. Nechita, A. Prechtel, A. Rupp, N. Suciu,
*Benchmark for numerical solutions of flow in heterogeneous groundwater formations*, arxiv 1911.10774. - C.D. Alecsa,
*The long time behavior and the rate of convergence of symplectic convex algorithms obtained via splitting discretizations of inertial damping systems*, arXiv:2001.10831 - C.D. Alecsa, S.C. László,
*Tikhonov regularization of a perturbed heavy ball system with vanishing damping*, http://doi.org/10.13140/RG.2.2.29212.92801. - E. Burma, M. Nechita, L. Oksanen,
*A stabilized finite element method for inverse problems subject to the convection-diffusion equation. II: convection-dominated regime*, 2020., arXiv:2006.13201

- N. Suciu,
*Global random walk solutions for flow in porous media*, accepted paper, ENUMATH 2019 Proceedings, to apear (Springer)

- C. I. Gheorghiu
*, A third-order nonlinear BVP on the half-line*, January 2020, https://www.chebfun.org/examples/ode-nonlin/GulfStream.html

- M. Nechita,
*Sir George Jessel studentship*, University College London (february 2020).

N. Suciu and O. Agratini have high Hirsch indexes in ISI and Scholar.

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

- C.D. Alecsa, I. Boros, M. Nechita, N. Suciu, code PRECISI-2020-43673
- C.D. Alecsa and I. Boros, code PRECISI-2020-47637
- C.D. Alecsa, code PRECISI-2020-45816

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

- F. Patrulescu, code PRECISI-2020-52827

–

**International conferences**

- C.D. Alecsa, I. Boros, F. Frank, P. Knabner, M. Nechita, A. Prechtel, A. Rupp, N. Suciu, D443:
*Numerical benchmark study for flow in highly heterogeneous aquifers*, EGU General Assembly 2020 – Sharing Geoscience Online, https://doi.org/10.5194/egusphere-egu2020-10504 - O. Agratini,
*Using the sequences of linear operators to approximate signals*, The 2nd International Conference on Mathematics and Computers in Science and Engineering, MACISE 2020, Madrid, Spain, January 18-20, 2020. https://www.macise.org/#Plenary - S.C. Laszlo, C.D. Alecsa, T. Pinta,
*An extension of the second order dynamical system that models Nesterov’s convex gradient method*, Games, Dynamics and Optimization (GDO2020), Rome, Italy, February 24-26, 2020.

National conferences

–

- 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), in progress at Erlangen-Nuernberg University.

- Studia UBB Math.: O. Agratini (senior Editor)
- J. Numer. Anal. Approx. Theory: O. Agratini (Editor-in-Chief), E. Catinas (Editor-in-Chief), I. Pavaloiu (deputy Editor-in-Chief), D. Otrocol, M. Nechita, I. Boros
- ROMAI Journal: N. Suciu, C.I. Gheorghiu
- Mathematica (Cluj): O. Agratini
- Open Journal of Discrete Mathematics: O. Agratini
- J. Science and Arts: O. Agratini

- Lupescu L. Adina, thesis
*Studiul funcțiilor circulare și aplicații*(coord. Prof. dr. Andrica Dorin), September 24, Babeș-Bolyai University - Chender E. Oana-Liliana, thesis
*Formule Rodrigues și aplicații*(coord. Prof. dr. Andrica Dorin), September 22, Babeș-Bolyai University - Pode Maria Camelia, thesis
*Transformări integrale ale unor clase speciale de funcții complexe*(coord. Prof. dr. Breaz Valer-Daniel), December 16, Babeș-Bolyai University - Magdaș G. A. Adrian, thesis
*Contribuții la teoria punctului fix pentru operatori ciclici și aplicații*(coord. Prof. dr. Petrușel Adrian), April 10, Babeș-Bolyai University - Kassab Wissam, thesis
*Rezultate de punct fix în spații modulare*(coord. Prof. dr. Postolache Mihai), March 4, Politehnica University Bucharest

- O. Agratini, for Alin Fodor (supervisor C. Pintea);
- O. Agratini, for Apan (married Pop) Beatrix-Mihaela (supervisor Duca Dorel)

- O. Agratini for: Studia Universitatis Babeș-Bolyai Mathematica (5), Journal of Numerical Analysis and Approximation Theory (1), Miskolc Mathematical Notes (1), Applied Mathematics – A Journal of Chinese Universities (1), Filomat (1), Constructive Mathematical Analysis (1), Mediterranean Journal of Mathematics (1), Results in Mathematics (1)
- C.I. Gheorghiu (to be completed)

for Mathematical Reviews:

- O. Agratini: MR4193203, MR4184053, MR4175410, MR4133637, MR4107231, MR4042301
- C. Mustăța: MR4137843, MR4129612, MR4081948
- D. Otrocol: MR4196234, MR4153514

for ZBL:

- C.I. Gheorghiu has written reviews for ZBL Math: 1462.65185, 1458.65148, 1458.65147, 1456.65153, 1456.65165, 1465.65124, 1458.65146, 1455.35060, 1454.65172, 1452.65342, 1452.65360, 1452.65371, 1452.65344, 1452.65343, 1458.65151, 1453.65403, 1454.65166, 1451.65211, 1448.65235, 1451.65207, 1451.65187, 1451.65200, 1483.76005, 1444.81011, 1447.65161, 1483.65005.

(to be completed)