Dr. Cristian-Daniel **Alecsa**

(former researcher at ICTP, between 2017-2021)

This website does not contain the papers elaborated after leaving ICTP.

Last update: February 21, 2022.

**Former position****:**

Research Assistant at *Tiberiu Popoviciu Institute of Numerical Analysis*

Postdoc, *Romanian Institute for Science and Technology*

**Research domains:**

- Optimization Methods for Machine Learning
- Data Science Techniques
- Scientific Computing & Numerical Algorithms
- Mathematical Modeling

**Personal Data**

Date and place of birth : 15.03.1990, Săveni, Botoșani

**Educational Background**

2005 – 2009 : High School „Dr. Mihai Ciucă”, Săveni, section Mathematics – Computer Science

2010 – 2013 : Faculty of Mathematics and Computer Science, “Babeş-Bolyai” University, Cluj-Napoca

2013 – 2015 : Master Studies at Faculty of Mathematics and Computer Science, “Babeş-Bolyai” University, Cluj-Napoca, field Applied Mathematics;

2015 – 2019 : Doctoral Studies at Faculty of Mathematics and Computer Science, “Babeş-Bolyai” University, Cluj-Napoca, field *Nonlinear Operators and Differential Equations*

**Employment Experience**

**3 February 2020 – ?**: Machine Learning Researcher at Romanian Institute of Science and Technology (RIST) : Postdoc position for the”DeepRiemann” project entitled “Riemannian Optimization Methods for Deep Learning” – funded European Regional Development Fund and the Romanian Government through the Competitiveness Operational Program 2014-2020

**1 January 2017 – January 2021**: Assistant Researcher at Tiberiu Popoviciu Institute of Numerical Analysis (ICTP), Romanian Academy, Cluj-Napoca, Romania

**3 July 2019 – 23 December 2019** : Machine Learning Engineer at EspresSoft-Tech SRL, Cluj-Napoca, Romania

**Conferences and Workshops **

- 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. - Interdisciplinary Conference for Phd Students, Baru Mare, Hunedoara, 3-5 June 2016
- Student Scientific Session, Phd Students, Cluj-Napoca, 31 May 2016
- Student Scientific Session, Phd Students, Cluj-Napoca, 6 June 2017
- Numerical Analysis, Approximation and Modeling (Symposium), Cluj-Napoca, 14 June 2017
- Național Session of Mathematics Scientific Communications, Iași, 6-9 July 2017
- Weekly Seminars at ‘Tiberiu Popoviciu’ Institute of Numerical Analysis, 2017
- PhD Scientific Reports at ‘Nonlinear Operators and Differential Equations’ Research Group, UBB, 2015-present

**Teaching Experience**

http://www.cs.ubbcluj.ro/files/orar/2015-1/cadre/alcc.html

Seminar – Basic Mathematics – first semester, 2015/2016, Mathematics for Computer Science (teaching in Romanian), Undergraduate (for 1st and 2nd year students)

Seminar – Differential Equations – first semester, 2015/2016, Mathematics (teaching in Romanian), Undergraduate (for 2nd year students)

Lab – Differential Equations – first semester, 2015/2016, Mathematics (teaching in Romanian), Undergraduate (for 2nd year students)

http://www.cs.ubbcluj.ro/files/orar/2015-2/cadre/alcc.html

Seminar – Special Topics of Differential Equations – second semester, 2015/2016, Mathematics and Mathematics for Computer Science (teaching in Romanian), Undergraduate (for 2nd year students)

Lab – Dynamical Systems – second semester, 2015/2016, Computer Science (teaching in English), Undergraduate (for 2nd year students)

http://www.cs.ubbcluj.ro/files/orar/2016-1/cadre/alcc.html

Lab – Probability and Statistics – first semester, 2016/2017, Computer Science (teaching in Romanian), Undergraduate (for 2nd year students)

Lab – Probability and Statistics – first semester, 2016/2017, Computer Science (teaching in English), Undergraduate (for 2nd year students)

Seminar – Differential Equations – first semester, 2016/2017, Mathematics (teaching in Romanian), Undergraduate (for 2nd year students)

Lab – Differential Equations – first semester, 2016/2017, Mathematics (teaching in Romanian), Undergraduate (for 2nd year students)

http://www.cs.ubbcluj.ro/files/orar/2016-2/cadre/alcc.html

Lab – Numerical Calculus – second semester, 2016/2017, Computer Science (teaching in English), Undergraduate (for 3rd year students)

Lab – Numerical Analysis – second semester, 2016/2017, Mathematics (teaching in Romanian), Undergraduate (for 2nd year students)

Lab – Dynamical Systems – second semester, 2016/2017, Computer Science (teaching in English), Undergraduate (for 1st year students)

http://www.cs.ubbcluj.ro/files/orar/2017-1/cadre/alcc.html

Lab – Mathematical Statistics – first semester, 2017/2018, Mathematics for Computer Science (teaching în Romanian), Undergraduate (for 3rd year students)

Seminar – Differential Equations – first semester, 2017/2018, Mathematics (teaching in Romanian), Undergraduate (for 2nd year students)

Seminar – Differential Equations – first semester, 2017/2018, Mathematics for Computer Science (teaching in Romanian), Undergraduate (for 2nd year students)

http://www.cs.ubbcluj.ro/files/orar/2017-2/cadre/alcc.html

Seminar – Dynamical Systems – second semester, 2017/2018, Computer Science (teaching in Romanian), Undergraduate (for 1st year students)

**Computer experience**

Programming languages: Matlab, C, C++, Maple, HTML, CSS, JQuery

Word-processing languages: LaTeX, Scientific Work Place, Beamer

**Languages **

English

- 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 - 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 - 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 - 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. - 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 - 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 - C.-D. Alecsa,
*The long time behavior and the rate of convergence of symplectic convex algorithms obtained via splitting discretizations of inertial damping systems*, (2020), arXiv:2001.10831 - C.D. Alecsa, A. Petruşel,
*Some variants of Ćirić’s multi-valued contraction principle,*Annals of West University of Timisoara – Mathematics and Computer Science,**57**(2019) no. 1, pp.23-42, https://doi.org/10.2478/awutm-2019-0004 - C.D. Alecsa,
*Sequences of contractions on cone metric spaces over Banach algebras and applications to nonlinear systems of equations and systems of differential equations*, International Journal of Nonlinear Analysis and Applications, 10, 2, 2019, 227-254. doi: 10.22075/ijnaa.2019.18884.2040 (not@ictp) - 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. *SERS assessment of the cancer-specific methylation pattern of genomic DNA: towards the detection of acute myeloid leukemia in patients undergoing hematopoietic stem cell transplantation*, Anal. Bioanal. Chem. 411 (2019) no. 29, pp. 7907–7913. (doi: , 10.1007/s00216-019-02213-2)- C.D. Alecsa,
*Common fixed points for Presic operators via simulation functions*, J. Nonlin. Conv. Analysis, 20 (2019) no. 3, 363-377. (not@ictp) - V. Moisoiu, A. Socaciu, A. Stefancu, S. D. Iancu, I. Boros, C. Alecsa, C. Rachieriu, A. R. Chiorean, D. Eniu, N. Leopold, C. Socaciu, D. Eniu,
*Breast cancer diagnosis by surface-enhanced Raman scattering (SERS) of urine*, Appl. Sci.,**9**(2019) no. 4, 806. - C. D. Alecsa,
*Approximating fixed points for nonlinear generalized mappings using Ishikawa iteration*, Rend. Circ. Mat. Palermo, II. Ser. 68 (2011) 1, pp. 163-191 (not@ictp) - C.D. Alecsa,
*Some fixed point results linked to α − β rational contractions and modified multivalued Hardy-Rogers operators*, J. Fixed Point Theory, 2018, 2018:3 (not@ictp) - C.D. Alecsa,
*Some fixed point results regarding convex contractions of Presić type*, J. Fixed Point Theory Appl. (2018) 20: 7. (not@ictp) - C.D. Alecsa,
*Fixed point theorems for generalized contraction mappings on b-rectangular metric spaces*, Studia Universitatis Babeş-Bolyai Mathematica, 62 (2017) No. 4, 499-524 (not@ictp) - C.D. Alecsa,
*Stability results and qualitative properties for Mann’s algorithm via admissible perturbations technique*, Applied Analysis and Optimization, 1 (2017) no. 2, 327-344. (not@ictp) - C. Alecsa,
*On new faster fixed point iterative schemes for contraction operators and comparison of their rate of convergence in convex metric spaces*, Int. J. Nonlinear Anal. Appl. 8 (2017) No. 1, 353-388. (not@ictp) - C.D. Alecsa, A. Petrusel,
*On some fixed point theorems for multi-valued operators by altering distance technique*, J. Nonlinear Var. Anal. 1 (2017), 237-251. (not@ictp)

Postdoc position at Romanian Institute of Science and Technology – for the”DeepRiemann” project entitled “Riemannian Optimization Methods for Deep Learning” – funded European Regional Development Fund and the Romanian Government through the Competitiveness Operational Program 2014-2020

Research Assistant at the Technical University of Cluj-Napoca – national research grant “Research Projects for Young Independent Teams” PN-III-P1-1.1-TE-2016-0266, entitled “Optimizare neneteda, convexa si neconvexa, o abordare din perspectiva sistemelor dinamice” (in Romanian)

GitHub projects: https://github.com/CDAlecsa

Contributor to a Deep Learning library: https://github.com/rist-ro/argo

Research Internship at the Research Group on Applied Mathematics, Faculty of Mathematics, University of Vienna, 05.11.2019 – 12.11.2019