Invited Speaker at WG 2019, June 19 -- June 21, 2019, Vall de Núria, Catalonia, Spain.
Invited Speaker at Spectrum 2019, 7th to 9th March 2019, IEM, Kolkata.
Invited Speaker at WALCOM 2019, February 27-- March 02, 2019, Guwahati, India.
Invited Speaker at Recent Advances in Algorithms MAY 22--26, 2017, St.Petersburg.
Invited Speaker at Gregory 60 -- celebrating 60th birthday of Gregoy Gutin, Royal Holloway University London, January 6th-7th, 2017, UK.
Invited Speaker at the Hong Kong Theory Day, 2017.
Invited Speaker at the National Level Workshop on Graph Theory: Algebraic and Algorithmic Aspects (GTA^3-2016), 19-24 December, 2016, Kolkota, India.
Invited Speaker for the session on Graph Decompositions and Parameterized Algorithms, SIAM Meetings on Discrete Mathematics, Atlanta, June 06-10, 2016.
Invited Speaker at the 42nd International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2016).
Invited Speaker at the workshop on Satisfiability Lower Bounds and Tight Results for Parameterized and Exponential-Time Algorithms, Simons Institute, Berkeley, Nov. 2-Nov. 6, 2015.
Invited Speaker for ELC/B01 Workshop on Parameterized Algorithms, University of Electro-communication, Tokyo, Japan
Invited Speaker at Indian Science Congress, Mumbai.
Invited speaker at the International Workshop on Combinatorial Algorithms (IWOCA), October 15-17, 2014, Duluth, USA.
Invited speaker for ICERM Semester Program on ``Network Science and Graph Algorithms'', February 3- May 9th 2014, Brown University, USA.
Invited speaker to 6th workshop on Graph Classes, Optimization, and Width Parameter (GROW 2013), October 9-11, 2013, Santroni Island, Greece.
Invited speaker to 14th Max Planck Advanced Course on the Foundations of Computer Science (ADFOCS 2013), August 5-9, 2013, Max-Planck Institute for Informatics, Germany.
Invited speaker at Worker 2013, April 9-13, 2013, University of Warsaw, Poland.
Invited speaker at the International Workshop on Combinatorial Algorithms (IWOCA), July 19-21, 2012, Kalasalingam University, India.
Invited speaker at the first workshop on Treewidth, May 19-20, 2011, University of Bergen, Bergen, Norway.
Invited speaker at the 2011 School in Approximability, January 5-9, 2011, India Institute of Science Campus, Bangalore, India.
Attended Dagstuhl Seminar on ``Exact Complexity of NP-hard Problems '' from 31st October 2010 to 05th November 2010 and gave a talk on ``Slightly Superexponential Parameterized Problems''.
Attended Dagstuhl Seminar on ``Parameterized complexity and approximation algorithms'' from 13th December 2009 to 17th December 2009 and gave a talk on ``Iterative Localization''.
Attended Bertinoro Workshop on ``Algorithms and Graphs'' from 6th December 2009 to 11th December 2009 and gave a talk on ``Fast FAST''.
Invited speaker at AGAPE School on Fixed Parameter and Exact Algorithms, May 25-29 2009, Lozari, Corsica (France).
Attended Dagstuhl Seminar on ``Adaptive, Output Sensitive, Online and Parameterized Algorithms'' from 19th April 2009 to 24th April 2009 and gave a talk on ``Lower Bounds on Kernelization''.
Visited Professor Dimitrios M. Thilikos, Department of Mathematics, University of Athens, 9th November 2008 to 22nd November 2008.
Attended Dagstuhl Seminar on ``Moderately Exponential Time Algorithms'' from 19th October 2008 to 24th October 2008.
Attended Update Meeting on Algorithms and Complexity held at The Institute of Mathematical Sciences from 10th March 2008 to 12th March 2008 and gave an invited talk on ``On Problems Without Polynomial Kernels''.
Attended Dagstuhl Seminar on ``Structure Theory and FPT Algorithmics for Graphs, Digraphs and Hypergraphs'' from 8th July 2007 to 13th July 2007 and gave a talk on ``Parameterized Algorithms for Directed Maximum Leaf Problems''.