Yann-Gaël Guéhéneuc is full professor at the Department of computer and software engineering of École Polytechnique de Montréal where he leads the Ptidej team on evaluating and enhancing the quality of object-oriented programs by promoting the use of patterns, at the language-, design-, or architectural-levels. He is IEEE Senior Member since 2010. In 2009, he was awarded the NSERC Research Chair Tier II on Software Patterns and Patterns of Software. He holds a Ph.D. in software engineering from University of Nantes, France (under Professor Pierre Cointe's supervision) since 2003 and an Engineering Diploma from École des Mines of Nantes since 1998. His Ph.D. thesis was funded by Object Technology International, Inc. (now IBM OTI Labs.), where he worked in 1999 and 2000. His research interests are program understanding and program quality during development and maintenance, in particular through the use and the identification of recurring patterns. He was the first to use explanation-based constraint programming in the context of software engineering to identify occurrences of patterns. He is interested also in empirical software engineering; he uses eye-trackers to understand and to develop theories about program comprehension. He has published many papers in international conferences and journals, including IEEE TSE, Springer EMSE, ACM/IEEE ICSE, and IEEE ICSM.