Let's think about a soft blog

Daniel Porumbel

Associate professor/maître de conférences
Combinatorial Optimization GroupCEDRIC CS Lab
CS department, CNAM, 292 rue Saint-Martin, Paris 3e
Contact: daniel.porumbel@removeme.cnam.fr +(33)1 40 27 24 33,

Research Context

I have applied such techniques to different problems: Graph-Coloring [J4,J11,C1,C3-C6], Vehicle or arc routing [J1,J7,J12], Cutting-Stock [J1,J3,J7], Isomorphism [J8,C2], p-median [J7], MaxMin Diversity [J10].

Expository work, papers submitted, in revision

Daniel Porumbel, Trying to demystify the characterizations of SDP matrices.pdf: I wrote this document, because I needed something I did not find elsewhere: a self-contained introduction to SDP for people who did learn (a lot of) maths in the past but do not work full time in (SDP) matrix theory. All in 100 pages, not 700. Suggestions or corrections are welcome. Self contained means that everything is proven from scratch, because I can't stand taking things for granted: no secret, no empty jargon, no more formulae out of the blue, no longer my(s)thification.

D. Porumbel, Cutting Planes by Projecting Interior Points onto Polytope Facets: pdf, source code

D. Porumbel, J.-K. Hao, Distance-Guided Local Search Submitted pdf draft

International Journals

[J1] Daniel Porumbel, Ray Projection for Optimizing Polytopes with Prohibitively Many Constraints in Set-Covering Column Generation, Mathematical Programming (pdf draft, source code), 155(1): 147-197, 2016 Springer©, doi link

[J2] Daniel Porumbel, From the Separation to the Intersection Sub-problem in Benders Decomposition Models with Prohibitively-Many Constraints, Discrete Optimization, 29:148-173, 2018 (pdf draft, source code, slides [fr]),

[J3] Daniel Porumbel, François Clautiaux, Convergent Dual Bounds Using an Aggregation of Set-Covering Constraints for Capacitated Problems, INFORMS Journal of Computing, 29(1):170-184, 2017. (pdf draft, slides, supplement)

[J4] D. C. Porumbel, J-K. Hao and P. Kuntz, A Search Space "Cartography" for Guiding Graph Coloring Heuristics. Computers & Operations Research, 37(4):769-778, 2010. (pdf draft), Elsevier©, doi link

[J5] Daniel Porumbel, Prize-Collecting Set Multi-Covering With Submodular Pricing, International Transactions in Operational Research, 25 (4):1221-1239, 2018, (pdf draft), Wiley-Blackwell©

[J6] D. Porumbel, G. Goncalvez, H. Allaoui; T. Hsu; Arc-Routing via Column Generation and Iterated Local Search in a Permutation Set-Covering Framework,
European Journal of Operational Research 256(2):349-367, 2017 pdf draft, slides Roadef 2015 (French OR congress) Elsevier© ,

[J7] D. Porumbel, G. Goncalves, Using Dual Feasible Functions to Construct Fast Lower Bounds for Routing and Location Problems, Discrete Applied Mathematics, 196: 83-99, 2015, (pdf draft), Elsevier©, doi

[J8] Daniel Porumbel. Isomorphism Testing using Polynomial-Time Graph Extensions. Journal of Mathematical Modelling and Algorithms, 10(2):119-143, 2011 (pdf draft, slides [fr], isomorphism program GI-Ext), Springer©, doi

[J9] D. C. Porumbel, J-K. Hao and P. Kuntz. An Efficient Algorithm for Computing the Distance Between Close Partitions. Discrete Applied Mathematics, 159(1):53-59, 2011, (pdf draft), Elsevier©, doi

[J10] D. C. Porumbel, Jin-Kao Hao, Fred Glover, A Simple and Effective Algorithm for the MaxMin Diversity Problem. Annals of Operations Research, 186 (1):275-293, 2011, (pdf draft, source code), Springer©, doi

[J11] D. C. Porumbel, J-K. Hao and P. Kuntz. An Evolutionary Approach with Diversity Guarantee and Well-Informed Grouping Recombination for Graph Coloring, Computers & Operations Research, 37(10):1822-1832, 2010 (pdf draft), Elsevier©, doi

[J12] Nathalie Helal, Frédéric Pichon, D. Porumbel, David Mercier, Éric Lefèvre. The capacitated vehicle routing problem with evidential demands, International Journal of Approximate Reasoning 95:124-151, 2018 (pdf) Elsevier©

[J13] D. C. Porumbel, J-K. Hao and P. Kuntz. Informed Reactive Tabu Search for Graph Coloring. Asia Pacific Journal of Operations Research, 30(4), pp. 1350010, 2013 (pdf draft), World Scientific Publishing©

International Conferences and Book Chapters:

[C1] D. Porumbel, J-K. Hao and P. Kuntz, Spacing Memetic Algorithms. In proceedings of GECCO 2011, GA track, 1061-1068. ACM. (pdf draft, slides)

[C2] G. Audemard, C. Lecoutre, M. S. Modeliar, G. Goncalves, D. Porumbel Scoring-based Neighborhood Dominance for the Subgraph Isomorphism Problem. The 20th International Conference on Principles and Practice of Constraint Programming (CP 2014)

[C3] Philippe Galinier, Jean-Philippe Hamiez, Jin-Kao Hao, Daniel Porumbel, Recent advances in graph vertex coloring, In I. Zelinka, V. Snasel, A. Abraham (eds.), Handbook of Optimization, Springer© (Intelligent Systems Series)

[C4] D. Porumbel, J-K. Hao and P. Kuntz, Diversity Control and Multi-Parent Recombination for Evolutionary Graph Coloring Algorithms. Evocop 2009 (9th European Conference on Evolutionary Computation in Combinatorial Optimisation, Tübingen, Germany), LNCS 5482: 121-132, 2009. (ps, pdf) Springer©  among the three best paper nominees

[C5] D. Porumbel, J-K. Hao and P. Kuntz, Position-Guided Tabu Search for Graph Coloring. Accepted for the post-proceedings of LION 2009 (Learning and Intelligent OptimizatioN conference, Trento, Italy), LNCS 5851:148-162, 2009. (paper draft, slides) Springer©

[C6] D. Porumbel, J-K. Hao and P. Kuntz, A study of evaluation functions for the graph K-coloring problem. Selected papers from the 8th International Conference on Artificial Evolution (Tours, France), LNCS 4926: 124-135, 2008. (ps, pdf) Springer© 

Expository work, reports, PhD

As far as I know, there is no relevant technical mistake in articles below. If you are interested to (re-)work, extend or (re)-submit, you can contact me.

[E1] D. Porumbel, Trying to demystify the Karush-Kuhn-Tucker conditions (pdf, html).

[E2] D. Porumbel, Revisiting the bijection between planar maps and well labeled trees (pdf). In this work, we provide alternative arguments and correct a slight error of a graph theory article from around 1970s/1980s.

[PhD] D. Porumbel, PhD thesis, English version, French version, dedicated to my grandfather.

More[+] (Seminars, theses)


I like writing software more then delegating. I try to systematically provide the source code for all my new algorithmic work, except for papers without implementation [J5, J9]. You can check my CODE_GUIDELINES used by most recent C++ projects. Exemples:

Projective Cutting Planes for Benders decompositions, Column Generation, a robust programming problem, ...
Replacing the separation sub-problem with the intersection sub-problem to solve a Benders reformulation model (2018)
Distance Guided Local Search for maximum weighted k-cluster or k-clique (2018)
Integer Ray Method for Column Generation for Cutting Stock and Capacitated Arc Routing (2014)
Heuristic for maximum minimum diversity (2011)
Isomorphism tool GI-Ext (2010)

Scientific Awards

I received the Simon Régnier prize in 2011. This prize is awarded each year by the "Société Francophone de Classification" (French-speaking Classification Society) to a researcher of maximum 35 years with a PhD thesis on classification. (slides)

Nominated for Best Paper Award (3 papers selected among more than 50), EvoCOP 2009

Bronze medal at the 41st International Mathematical Olympiad, a problem-solving competition with contestants from almost 100 countries (ranked 2nd in the qualification rounds of Romania), South Korea, 2000

Diploma for Academic Excellence of Romania's President Emil Constantinescu, 2000

Service for the Scientific Community

I accepted review invitations from the editorial board of different journals since 2017: Computational Optimization and Applications, European Journal of Operational Research, IEEE Transactions on Cybernetics, Computers and Operations Research , Transportation Research part E. Engineering Optimization. Before 2017, I performed reviews for journals like: Canadian Mathematical Bulletin, Journal of Artificial Intelligence Research, The Computer Journal, IEEE Transactions on Evolutionary Computation, European Journal of Operations Research, Computers and Operations Research , Evolutionary Computation, Computers & Mathematics with Applications, Information Processing Letters, Expert Systems and Applications, Engineering Applications of Artificial Intelligence, Computing. I was in the program committee of different conferences (Evocop 2012, Evocop 2013, Evocop 2014, Evocop 2019, Gecco Ecom 2013, Gecco Ecom 2014, Gecco Ecom 2015, Gecco Ecom 2016, Gecco Ecom 2017, Gecco Ecom 2018, Gecco Ecom 2019). I also reviewed some papers indirectly (as a sub-reviewer) a few times (e.g., for ICTAI, CEC, GECCO, MOSIM).

I (co-)advised a PhD thesis: Nathalie Helal, An evidential answer for the capacitated vehicle routing problem with uncertain demands, defended in 2017 (main adviser: Eric Lefèvre, second adviser Frédéric Pichon, collaboration with David Mercier). I adivised some master theses along the years: Thomas Ridremont (Robust optimisation of wiring in renewable-energy installations, with Marie-Christine Costa and Cédric Bentz, 2015); Hubert Arnoux (A tool of visualisation techniques for local search methods, with J-K Hao, P. Kuntz, 2012); Junlin Zhu (Mathematical Programming Models for Graph Isomorphism, with Amélie Lambert, 2015); Ben Ibrahima Badji (Meta-heuristics for the Arc-Routing Problem, with T. Hsu, H. Allaoui, G. Goncalves, 2014); Fahrur Rozi and Mochammad Luthfi (Airport passenger flow simulation in Quest and Arena and resource allocation optimization, with G. Gonvalves, 2011).

I created a library for Graph Coloring Benchmarking during my PhD thesis.