English Version


Data si locul nasterii: 4 august 1975, Curtea-de-Arges, Arges.

Educatia: Absolvent al Facultatii de Matematica, Universitatea Bucuresti, 1998. Master's of Science, Informatica, University of Western Ontario, Canada, 1999.
Teza de doctorat: "Unconventional models of computation: DNA and membrane computing", University of Western Ontario, Canada, 2003. Cond. stiintific: Dr. Sheng YU.
Pozitii academice: Conferentiar Universitar, Cercetator Stiintific gradul I (INCDSB), Conducator de doctorat in SUA din 2004 (3 doctoranzi supervizati ca unic conducator).
Cursuri predate: Limbaje formale, Retele de calculatoare, Analiza algoritmilor, Programare orientata pe obiecte, Programare in asamblare pentru microprocesoarele Intel, Introducere in Bioinformatica, Elemente de Biocomputing, Programare Procedurala etc.
Domenii de interes stiintific: Limbaje formale si automate, modele de calcul inspirat din biologie, Systems Biology si bioinformatica, simulare de fenomene intra-celulare in special cascadele de reactii legate de apoptoza.
Pagina personala: http://funinf.cs.unibuc.ro/~apaun/.

Premii si distinctii

Lucrarea: "The Power of Communication: P Systems with Symport/Antiport" a fost selectata de catre Thomson ISI Essential Science Indicators ca lucrare foarte influenta/citata si este estimata ca fiind intre cele mai bune 1% lucrari din domeniu. Fraza exacta de pe certificatul de la ISI este: "This means that the number of citations your article received places it in the top 1% within its field according to Essential Science Indicators. Your work is highly influential, and is making a significant impact among your colleagues in your field of study."

Membru in comisii, asociatii, colective de redactie

  • Membru in PC la conferinte academice internationale:
    • Program Committee member for Sixteenth International Meeting on DNA Computing (DNA 16), Hong Kong, China, June 14-17, 2010
    • Program Committee member for Fifteenth International Conference on Implementation and Application of Automata (CIAA2010) (Winnipeg, Manitoba, Canada, August 12-15, 2010)
    • Program Committee member for the 6th International Symposium on Bioinformatics Research and Applications (ISBRA'10), to be held on May 23-26, 2010 at the University of Connecticut in Storrs, CT.\
    • Program Committee member for Fifteenth International Meeting on DNA Computing (DNA 15), Fayetteville, Arkansas, USA, 2009
    • Program Committee member for Thirteenth International Conference on Implementation and Application of Automata (CIAA2008) (Santa Barbara, 2008)
    • Publicity Committee Co-Chair for Thirteenth International Conference on Implementation and Application of Automata (CIAA2008) (Santa Barbara, 2008)
    • Program Committee member for Third International Conference on Bio-Inspired Computing: Theories and Applications (BIC-TA 2008) Adelaide, Australia, 2008.
    • Program Committee member for First International Conference on Contemporary Computing (NOIDA, (outskirts of New Delhi), India 2008)
    • Program Committee member for Language Theory in Biocomputing 07 (Kingston, Canada 2007)
    • Program Committee member for Thirteenth International Meeting on DNA Computing (DNA13) (Memphis, USA, 2007)
    • Program Committee member for Eleventh International Conference on Implementation and Application of Automata (CIAA06) (Taipei, Taiwan 2006).
    • Student committee chair and organizer of UWORCS2002: U.W.O. Research in Computer Science, (London, Canada, 2002).
    • Organizing committee member for Fifth International Conference on Implementation and Application of Automata (CIAA 2000) and Half Century of Automata Theory Celebration and Inspiration (HCAT), London, Ontario, Canada, 2000.

Lucrari publicate in reviste internationale

  1. *O.H. Ibarra, A. Paun, A. Rodriguez-Paton, Sequential SNP systems based on min/max spike number, Theoretical Computer Science, vol. 410, iss. 30-32 (2009), 2982-2991 (Factor de impact ISI: 0,843).
  2. *A. Paun, M. Paun, A. Rodriguez-Paton, On the Hopcroft's minimization technique for DFA and DFCA, Theoretical Computer Science, vol. 410, iss. 24-25 (2009), 2424-2430 (Factor de impact ISI: 0,843).
  3. * J. Jack, A. Paun, A. Rodriguez-Paton, Discrete nondeterministic modeling of the FAS pathway, International Journal of Foundations of Computer Science, vol. 19 (October 2008), no. 5, pp. 1147-1162. (Factor de impact ISI:0,500)
  4. H. Chen, M. Ionescu, T.O. Ishdorj, A. Paun, Gh.Paun, M. Perez-Jimenez, Spiking neural P systems with extended rules: universality and languages. Nat. Comput. 7 (2008), no. 2, pp. 147-166. (revista ISI).
  5. O.H. Ibarra, A. Paun, Computing with Cells: Membrane Systems - Some Complexity Issues, International Journal of Parallel, Emergent and Distributed Systems, 23:5, 2008, pp. 347 -365
  6. O.H. Ibarra, S. Woodworth, F. Yu, A. Paun, On spiking neural P systems and partially blind counter machines. Nat. Comput. 7 (2008), no. 1, pp. 3–19. (revista ISI).
  7. A. Paun, Gh. Paun, Small universal spiking neural P systems, BioSystems, 90 (1), 2007, pp. 48-60. (Factor de impacto ISI:1,080)
  8. O. H. Ibarra, A. Paun, Gh. Paun, A. Rodriguez-Paton, P. Sosik, S. Woodworth; Normal forms for spiking neural P systems. Theoretical Computer Science 372(2-3), 2007, 196-217. (Factor de impact ISI: 0,843).
  9. *S. Cheruku, A. Paun, F.J. Romero-Campero, M.J. Perez-Jimenez, O.H. Ibarra; Simulating FAS-induced apoptosis by using P systems. Progress in Natural Science, 17(4), 2007, pp. 424-431. (Factor de impact ISI:0,531).
  10. *A. Paun, B. Popa; P Systems with Proteins on Membranes. Fundamenta Informaticae, 72, 4, 2006, 467-483. (Factor de impact ISI:0,586).
  11. *C. Campeanu, A. Paun, J.R. Smith, Incremental construction of minimal deterministic finite cover automata. Theoretical Computer Science, 363(2), 2006, 135-148 (Factor de impact ISI: 0,843).
  12. R. Freund, M. Oswald, A. Paun, Optimal Results for the Computational Completeness of Gemmating (Tissue) P Systems, International Journal of Foundations of Computer Science, 16(5), (2005), pp. 929-942. (Factor de impact ISI:0,500)
  13. *C. Campeanu, L. Kari, A. Paun, Results on Transforming NFA into DFCA, Fundamenta Informaticae, Vol 64 (2005), pp. 53-63. (Factor de impact ISI:0,586).
  14. R. Freund, A. Paun, P systems with active membranes and without polarizations, Journal of Universal Computer Science and Soft Computing, 9 (9), (2005), pp.657-663. (Factor de impact ISI:0,516)
  15. *S.N. Krishna, A. Paun, Results on Catalytic and Evolution-Communication P Systems, New Generation Computing, 22, 4 (2004), pp. 377-394. (Factor de impact ISI:0,694)
  16. *C. Campeanu, A. Paun, Counting the Number of Minimal DFCA Obtained by Merging States, International Journal of Foundations of Computer Science, Vol. 14, No. 6 (2003), pp. 995-1006. (Factor de impact ISI:0,500)
  17. R. Belu, A. Paun, A. Belu, Neural Networks in Instrumentation, Measurement and Control, Romanian Journal of Information Science and Technology, Vol. 6, No. 1-2, (2003), pp. 61-85. (ISI journal).
  18. M. Ionescu, C. Martin-Vide, A. Paun, Gh. Paun, Unexpected universality results for three classes of P systems with symport/antiport, Natural Computing, Vol. 2, issue 4, (2003), pp. 337-348. (revista ISI).
  19. A. Paun, Gh. Paun, G. Rozenberg, Computing by Communication in Networks of Membranes, International Journal of Foundations of Computer Science, Vol. 13, No. 6 (2002), pp. 779-798. (Factor de impact ISI:0,500)
  20. *C. Martin-Vide, A. Paun, G. Rozenberg, Membrane Systems with Coupled Transport: Universality and Normal Forms, Fundamenta Informaticae, 49, 1-3 (2002), pp. 1-15. (Factor de impact ISI:0,586).
  21. *A. Paun, Gh. Paun, The Power of Communication: P Systems with Symport /Antiport, New Generation Computing, 20, 3 (2002), pp. 295-305. (Factor de impact ISI:0,694)
  22. *A. Paun, P Systems with Global Rules, Theory Comput. Systems, 35, (2002), pp. 471-481. (Factor de impact ISI:0,769).
  23. *C. Campeanu, A. Paun, S. Yu, An Efficient Algorithm for Constructing Minimal Cover Automata for Finite Languages, International Journal of Foundations of Computer Science, 13, 1 (2002), pp. 83-97. (Factor de impact ISI:0,500)
  24. *A. Paun, On P Systems with Partial Parallel Rewriting, Romanian Journal of Information Science and Technology, 4, 1-2 (2001), pp. 203-210. (revista ISI).
  25. L. Kari, A. Paun, String Operations Suggested by DNA Biochemistry: the Balanced Cut Operation, Words, Semigroups & Transductions (M. Ito, et. al., eds.), World Scientific, Singapore, 2001, pp. 275-287.
  26. *A. Paun, On the Diameter of Various Classes of H Systems, J. Automata, Languages and Combinatorics, 5, 3 (2000), pp. 315-324.
  27. A. Paun, On Time-Varying H systems, Bulletin of the EATCS, 67 (1999), pp. 157-164.
  28. *A. Paun, Controlled H Systems of a Small Radius, Fundamenta Informaticae, 31, 2 (1997), pp. 185-193. (Factor de impact ISI:0,586).

Lucrari la conferinte (toate referite de comitete internationale)

  1. O.H. Ibarra, A. Paun, A. Rodriguez-Paton, Sequentiality Induced by Spike Number in SNP Systems, Pre-proceedings of Fourteenth meeting on DNA Computing (DNA14), June 2-6, 2008, Prague, Czech Republic, pp. 36-47.
  2. J. Jack, A. Paun, A. Rodriguez-Paton, Effects of HIV-1 Proteins on the Fas-Mediated Apoptotic Signaling Cascade: A Computational Study of Latent CD4+ T Cell Activation, accepted at Ninth Workshop on Molecular Computation, WMC9, Edinburgh (UK) July 28-31, 2008, 20pp.
  3. A. Paun, M. Paun, A. Rodriguez-Paton, Hopcroft's minimization technique: queues or stacks?, CIAA 13, July 21-24, 2008, San Francisco, USA, Lecture Notes in Computer Science, Berlin, vol. 5148, 2008, pp. 78-91.
  4. A. Paun, B. Popa, P Systems with Proteins on Membranes and Membrane Division, Proc of. Tenth International Conference Developments in Language Theory (DLT 2006), June 26-29, 2006, Santa Barbara, CA, USA, Lecture Notes in Computer Science, Berlin, vol. 4036, 2006 pp. 292-303
  5. H. Nagda, A. Paun, A. Rodriguez-Paton, P Systems with Symport/Antiport and Time, Proc. of Workshop on Membrane Computing (at the crossroads of Cell Biology and Computing), WMC07, 17-21 July 2006, Lecture Notes in Computer Science, Berlin, vol. 4361, 2006, pp. 429-442.
  6. C. Campeanu, A. Paun, J. R. Smith, Tight Bounds for the State Complexity of Deterministic Cover Automata, Proc. of Descriptional Complexity of Formal Systems, 8th Workshop, June 21-23, 2006, Las Cruces, New Mexico, USA (9 pages).
  7. M. Ionescu, A. Paun, Gh. Paun, M.J. Perez-Jimenez, Computing with Spiking Neural P Systems: Traces and Small Universal Systems, Proc. of 12th Intern. Meeting on DNA Based Computers (DNA 2006), June 5-9, Seoul, Korea, Lecture Notes in Computer Science, Berlin, vol. 4287, 2006, pp. 1-16.
  8. O.H. Ibarra, S. Woodworth, F. Yu, A. Paun, On Spiking Neural P Systems and Partially Blind Counter Machines. Proc. Of 5th International Conference on Unconventional Computation (UC 2006), 4th-8th September 2006, York, UK, Lecture Notes in Computer Science, Berlin, vol. 4135, 2006, pp. 113-129.
  9. C. Campeanu, A. Paun, J. R. Smith, An Incremental Algorithm for Minimal Deterministic Finite Cover Automata, Proc. of Tenth International Conference on Implementation and Application of Automata (CIAA05), June 27–29, 2005, Sophia Antipolis, France, pp. 90-103; (the conference had approximately 30% acceptance rate) also in Lecture Notes in Computer Science, Berlin, vol. 3845, 2006, pp. 90-103.
  10. O.H. Ibarra, A. Paun, Counting Time in Computing with Cells, Proc. of 11th Intern. Meeting on DNA Based Computers (DNA11), June 6-9, 2005, London Ontario, Canada, pp. 112-128, also in Lecture Notes in Computer Science, Berlin, vol. 3892, 2006, pp. 112-128.
  11. C. Campeanu, A. Paun, NFA to DFCA Transformations For Binary Alphabets, Proc. of Ninth International Conference on Implementation and Application of Automata (CIAA 2004), Kingston, Canada (2004).
  12. C. Campeanu, A. Paun, Lower Bounds for NFA to DFCA Transformations, Proc. of Descriptional Complexity of Formal Systems, 6th Workshop, London, Ontario, Canada (2004) (10 pages).
  13. R. Freund, M. Oswald, A. Paun, Extended Gemmating P Systems are Computationally Complete with Four Membranes, Proc. of Descriptional Complexity of Formal Systems, 6th Workshop, London, Ontario, Canada (2004) (10 pages).
  14. R. Freund, M. Oswald, A. Paun, P systems generating trees, Proc. of Workshop on Membrane Computing 2004 (WMC5), Milano, Italy, 2004, pp. 221-232 also in Lecture Notes in Computer Science, 3365, Berlin, (2004), pp. 309-319.
  15. C. Campeanu, A. Paun, Computing Beyond the Turing Limit Using the H Systems, Proc. of the Tenth International Meeting on DNA Computing (DNA10), Milan, (2004), pp. 314-323 also in Lecture Notes in Computer Science, 3384, Berlin, (2005), pp. 24-34.
  16. F. Bernardini, A. Paun, Universality of Minimal Symport/Antiport: Five Membranes Suffice, Lecture Notes in Computer Science, 2933, Berlin, (2004), pp. 43-54.
  17. R. Freund, A. Paun, Membrane Systems with Symport/Antiport: Universality Results, Lecture Notes in Computer Science, 2597, Berlin, (2003), pp. 270-287.
  18. C. Campeanu, A. Paun, The Number of Similarity Relations and the Number of Minimal Deterministic Finite Cover Automata, Proc. of 7th International Conference on Implementation and Application of Automata (CIAA 2002), Tours, France, 2002, pp. 71-80.
  19. M. Ionescu, C. Martin-Vide, A. Paun, Gh. Paun, Membrane Systems with Symport/Antiport: (Unexpected) Universality Results, Proc. of 8th Intern. Meeting on DNA Based Computers (DNA8) (M. Hagiya, A. Obuchi, eds.), Hokkaido University, Sapporo, Japan, 2002, pp. 151-160.
  20. A. Paun, P Systems with string-objects: Universality results, Proc. of Workshop on Membrane Computing (WMC-CdeA 2001), Curtea-de-Arges, Romania, 2001, pp. 229-242.
  21. A. Paun, On P Systems with Global Rules. Proc. of 7th Intern. Meeting on DNA Based Computers (DNA7) (N. Jonoska, N.C. Seeman, eds.), Tampa, Florida, USA, 2001, pp. 43-52.
  22. A. Paun, On P Systems with Active Membranes, Proc. of UMC2K, in Discrete Mathematics and Theoretical Computer Science, Springer (I. Antoniou, C.S. Calude, M.J. Dinneen, eds.), Brussels, Belgium, 2000, pp. 187-201.
  23. A. Paun, N. Santean, S. Yu, An O(n2) Algorithm for Constructing Minimal Cover Automata for Finite Languages, Proc. of Fifth International Conference on Implementation and Application of Automata (CIAA 2000) (M. Daley, M. Eramian, S. Yu, eds.), London, Ontario, 2000, pp. 233-241.
  24. A. Paun, On the Diameter of Various Classes of H Systems, Proc. of Intern. Workshop on Descriptional Complexity of Automata, Grammars and Related Structures (DCAGRS '99) (J. Dassow, D. Wotschke, eds.), Magdeburg, Germany, 1999, pp. 165-174.
  25. A. Paun, M. Paun, State and Transition Complexity of Watson-Crick Finite Automata, Proc. of Fundamentals of Computation Theory Conf. (FCT'99) Iasi, 1999, Lecture Notes in Computer Science, 1684, Springer-Verlag, Berlin, 1999, pp. 409-420.
  26. A. Paun, M. Paun, Controlled and Distributed H Systems of a Small Radius, Computing with Bio-Molecules; Theory and Experiments, Springer, Singapore, 1998, pp. 239-254.

Rapoarte tehnice

  1. R. Freund, A. Paun, P Systems with Active Membranes and without Polarizations, Dept. of Computer Sciences and Artificial Intelligence, Univ. of Sevilla Tech. Rep 01/2004, Second Brainstorming Week on Membrane Computing, Sevilla, Spain, Feb 2-7, 2004, pp. 193-205.
  2. S.N. Krishna, A. Paun, Some Universality Results on Evolution-Communication P Systems, Rovira i Virgili Univ., Tech. Rep. No. 26, Brainstorming Week on Membrane Computing; Tarragona, 2003, pp. 207-215.
  3. S.N. Krishna, A. Paun, Three Universality Results on P Systems, Rovira i Virgili Univ., Tech. Rep. No. 26, Brainstorming Week on Membrane Computing; Tarragona, 2003, pp. 198-206.
  4. A. Paun, A. Rodriguez-Paton, Further Remarks on P Systems with Symport Rules, An. Stiint. Univ. Al. I. Cuza Iasi Inform. 10 (2001), pp. 3-18.
  5. A. Paun, M. Paun, On the Membrane Computing Based on Splicing, Where Mathematics, Computer Science, Linguistics and Biology Meet (C. Martin-Vide, V. Mitrana, eds.), Kluwer, Dordrecht, 2001, pp. 409-422.

Capitole de carte

  1. O.H. Ibarra, A. Paun, Membrane Systems: A "Natural" Way of Computing with Cells, book chapter (chapter 3, 26 pages), in S. Rajasekaran, J.Reif, eds., Handbook of Parallel Computing: Models, Algorithms and Applications (Chapman & Hall/Crc Computer & Information Science Series), 2007, ISBN: 978-1584886235.
  2. A. Paun, I. Stanciu, A. Bancila, B. Popa, Calculabilitatea pe baza de membrane si proteine, book chapter in Bioinformatica vol II, Editura Tehnica, 131 pagini, 2008, ISBN: 978-973-31-2342-2.
  3. R. Freund, O. Ibarra, A. Paun, P. Sosik, H-C. Yen, Catalytic P systems, book chapter in Membrane Computing Handbook, to appear.
  4. O.H Ibarra, A. Leporati, A. Paun, S. Woodworth, Spiking Neural P Systems: Characterizations and Complexity, book chapter in Membrane Computing Handbook, to appear.

Carti

  1. A. Paun, Computability of the DNA and Cells: Splicing and Membrane Computing, SBEB Publishing, 378 pages, 2008, ISBN: 978-0-9802368-4-2.
  2. S. Yu, A. Paun, eds., Implementation and Application of Automata, Lecture Notes in Computer Science 2088, Springer-Verlag, Berlin, 2001. ISBN: 978-3540424918.
  3. A. Paun, M. Paun, Analiza Statistica Folosind Limbajul R, Editura Matrix, Bucuresti, 2009



Annals of the University of Bucharest (Mathematical Series)

 

Annals of the University of Bucharest (mathematical series), ISSN 2067-9009 is a mathematical research journal, published by the University of Bucharest, Faculty of Mathematics and Computer Science. This journal continues Analele Universitatii din Bucuresti-Matematica, founded in 1952. Annals of the University of Bucharest (mathematical series) aims at publishing high level original research papers and surveys, in all areas of pure and applied mathematics. The papers published in this journal are abstracted in Mathematical Reviews and Zentralblatt Math. The journal consists of one yearly volume divided in 2 issues. Contributions should be in English and should be sent to one of the members of the Editorial Board or to one of the Editorial Secretaries.

Information for authors. LaTex template.

EDITORIAL OFFICE


FACULTY of MATHEMATICS and COMPUTER SCIENCE
UNIVERSITY of BUCHAREST
Str. Academiei 14
010014 Bucharest, Romania

Contact: annalsub  fmi.unibuc.ro

ISSN 2067-9009

Seria Matematica     Scurt Istoric

EDITORIAL BOARD

CABIRIA ANDREIAN-CAZACU (University of Bucharest, Cabiria.Andreian@imar.ro) • VIOREL BARBU (University of Iasi, vb41@uaic.ro) • LUCIAN BEZNEA ("Simion Stoilow" Inst.of Math., Lucian.Beznea@imar.ro) • HAIM BREZIS (The State University of New Jersey, brezis@math.rutgers.edu) • STEFAAN CAENEPEEL (Vrije Universiteit Brussel, scaenepe@vub.ac.be) • ION CHITESCU (University of Bucharest, ionchitescu@yahoo.com) • PHILIPPE CIARLET (City University of Hong Kong, MAPGC@cityu.edu.hk) • DOINA CIORANESCU (Universite Pierre et Marie Curie, cioran@ann.jussieu.fr) • NICOLAIE D. CRISTESCU (University of Bucharest, cristesc@ufl.edu) • ROMULUS CRISTESCU (University of Bucharest, romuluscristescu@yahoo.com) • IOAN CUCULESCU (University of Bucharest, icucul@fmi.unibuc.ro) • NICOLAE DINCULEANU (University of Florida, nd@math.ufl.edu) • VIOREL IFTIMIE(University of Bucharest, viftimie@fmi.unibuc.ro) • GEORGE GEORGESCU (University of Buchares​t, georgescu@fmi.unibuc.ro) •  PALTIN IONESCU (University of Bucharest, Paltin.Ionescu@imar.ro) • MARIUS IOSIFESCU ("Gh. Mihoc-C. Iacob" Inst. of Math. Statist. and Appl. Math, miosifes@acad.ro) • YVON MADAY (Universite Pierre et Marie Curie, maday@ann.jussieu.fr) • GERARD MAUGIN (Universite Pierre et Marie Curie, gerard.maugin@upmc.fr) • JEAN MAWHIN (Universite Catholique de Louvain, Jean.Mawhin@uclouvain.be) • PETRU MIRONESCU (Université de Lyon, mironescu@math.univ-lyon1.fr) • CONSTANTIN NASTASESCU (University of Bucharest, constantin_nastasescu@yahoo.com) • LIVIU ORNEA (University of Bucharest, lornea@gta.math.unibuc.ro) • DORIN POPESCU (University of Bucharest, Dorin.Popescu@imar.ro) • VASILE PREDA (University of Bucharest, preda@fmi.unibuc.ro) • ROGER TEMAM (Indiana University, temam@indiana.edu) • IOAN TOMESCU (University of Bucharest, ioan@fmi.unibuc.ro)



EDITOR-IN-CHIEF:
MANAGING EDITOR:

EDITORIAL SECRETARIES:
RADU MICULESCU, University of Bucharest, miculesc@yahoo.com
MIHAI-SORIN STUPARIU, University of Bucharest, stupariu@fmi.unibuc.ro

 

 

 

 

 

 

Volume 6 (LXIV), Nr. 2, 2015

SUMAR - SOMMAIRE - CONTENTS


 Oanh Chau - A class of parabolic evolutional inequalities and application to contact problem

 Sanjib Kumar Datta, Tanmay Biswas and Debasmita Dutta - Comparative growth measures of differential monomials and differential polynomials depending on their relative orders

 Giorgio Giorgi - Notes and comments on sufficient first-order optimality conditions in scalar and vector optimization

 Monica Patriche - On the maximal reduction of games

 Vladimir Ryazanov - On Hilbert and Riemann problems. An alternative approach

 Gurucharan Singh Saluja - Convergence of general iteration scheme for total asymptotically nonexpansive mappings in CAT(0) spaces

 Balwant Singh Thakur, Rajshree Dewangan and Mohammad Saeed Khan - Strong convergence of two finite families of asymptotically pseudocontractive mappings





2002 - 2015 -- Facultatea de Matematica si Informatica, Universitatea din Bucuresti
Str. Academiei nr. 14, sector 1, C.P. 010014, Bucuresti, Romania
Tel: (4-021) 314 2863, Fax: (4-021) 315 6990, secretariat  fmi.unibuc.ro