4C Anniversary Celebration

Click here to see more photos from the event.

CP 2012 in Quebec City

Click here to see more photos from the conference.

I was a co-author for three papers in this year's CP conference. Nicolas and myself had a paper in the technical track of the conference, describing our Model Seeker tool. Model Seeker Presentation Poster

The second paper describes our (Deepak Mehta, Barry O'Sullivan and myself) solution to the ROADEF/EURO challenge of this year. Our team, S38, came second overall, with a specific constraint based approach implementing a large neighborhood search. This paper was in the application track of the conference. Machine Reassignment Presentation Poster

The third paper was in the multi-disciplinary track of the conference. It is about energy price aware scheduling, combining machine learning for the prediction of the energy price in Ireland, and optimization for a scheduling problem. This joint work with Georgiana Ifrim and Barry O'Sullivan. Energy Price Presentation Poster

In another part of the conference was a panel on future research directions for Constraint Programming. I helped to put a position paper together, the other authors are Nicolas Beldiceanu, Pierre Flener, Jean-Noel Monette and Justin Person from the Ecole des Mines de Nantes and from Uppsala University. Poster

Constraints Journal

A paper on "Partial Symmetry Breaking by Local Search in the Group" has been published in the Constraints Journal. This is an extended version of a paper we submitted to the SYMCON 09 workshop. SBNO Paper

International Symposium on Mathematical Programming (ISMP 2012) in Berlin

I gave a presentation of the ModelSeeker system I developed together with Nicolas Beldiceanu from the Ecole des Mines de Nantes. The slides from the talk are here.

There will be more on the ModelSeeker next week at the CoCoMile2012 workshop of ECAI2012 and at CP2012 in Quebec.

CP-AI-OR 2012 in Nantes

I gave an invited talk on optimization with variable energy prices (abstract) at the conference. The slides are here. All presentations at the conference were recorded and are available as videos in itunes. A link to the list of talks is here.

CP 2011 in Perugia

Just a hint: Clicking on the images will lead to galleries of additional images.

CP 2011 - Day 4

CP 2011 - Day 3

CP 2011 - Day 2

CP 2011 - Day 1

Images from Perugia


The slides from my presentation are here.

ModRef 2011

Nicolas and myself have been working on an extension of the Constraint Seeker for automated modelling of problems from examples. A description of our first attempt is in this paper.

Paper in the Main Conference Program

Our paper on the Constraint Seeker has been accepted for the CP 2011 conference in Perugia, Italy, in the application track. The latest version of the paper is here, the presentation is here.


Nicolas and myself had a short version of our ModRef paper in the Irish AI conference in Derry this year. The paper is here, the presentation is there.

A Constraint Seeker

The global constraint catalog is a very useful resource for learning about all the different global constraints that have been decribed in the literature. But it can be challenging to find the right constraint, if you do not already know its name. Nicolas Beldiceanu and myself have been working on a web application which helps you find constraints in the catalog, given positive or negative examples. We have written a paperUpdated version on this system, and a prototype is now running at Web Application. You may want to read Basic Help before entering your own queries.

CP-AI-OR 2011, in Berlin

Barry and I have a paper at CP-AI-OR 2011 on packing almost squares into the smallest possible rectangle (Paper). This is a generalization of our previous work on packing squares into rectangles, presented at CP2008.

Irish Collegiate Programming Contest 2011

Images from the Competition held at UCC on Saturday, March 26th.

CSCLP 2010 in Berlin

Tarik and myself propose an instance generator to test resource cost aware scheduling constraints. The code for the generator is available from Tarik's webpage. Our paper at the CSCLP workshop on Creating Tests for a Family of Cost Aware Resource Constraints describes its functionality (Presentation).

Barry and myself reported on the Almost Square Packing Problem (Presentation), a variant of the square packing problem we looked at in our CP2008 paper.

ICTAI 2010 in Arras

Tarik and myself presented a paper at the ICTAI conference in October on Multicriteria Reasoning Considering Reliability or Availability (Presentation), which extends our results for the CRAGS workshop.

CP2010 Conference in St. Andrews

I have one joint paper in the main conference programme, about the visualization package CP-Viz: A Generic Visualization Platform for CP (Presentation) with Paul Davern, Jacob Feldman, Deepak Mehta, Luis Quesada and Mats Carlsson.

CROCS 2010

Tarik Hadzic and myself presented a paper on A Family of Resource Constraints for Energy Cost Aware Scheduling (Presentation) at the Computational Sustainability workshop (CROCS2010) in St. Andrews.

ModRef 2010

Another paper on A Resource Cost Aware Cumulative (Presentation) with Tarik Hadzic was presented at the ModRef 2010 workshop.

CRAGS 2010

And yet another workshop paper, again with Tarik Hadzic, on Reasoning about Reliability and Cost using Decision Diagrams and Syntax Trees (Presentation) for the CRAGS workshop in St. Andrews.

ACP Executive Committee

I have been elected as a member of the executive committee of the ACP (Association for Constraint Programming) for a four year period (2011-2014). My election statement is here.


The software for the CP-Viz visualizer has been moved to sourceforge. The project can be found here. The software is described in our CP2010 paper.


I've started a blog on constraint applications.

Computational Sustainability, June 28-30, 2010, Boston, MA

Constraint-Based Scheduling for Reducing Peak Electricity Use (Presentation) (Abstract) with T. Hadzic

S4 Envisa Colloquium, June 21/22, 2010, Cork, Ireland

An Overview of Constraint Applications (Invited Presentation)

CP-AI-OR 2010 Workshops, June 15th, 2010, Bologna, Italy

An Energy Cost Aware Cumulative (Presentation) (Extended Abstract) with T. Hadzic in "Bin Packing and Placement Constraints (BPPC10)"

CP-VIZ: An Open Source Visualization Platform for CP (Presentation) (Abstract) with P. Davern in "Open Source Tools for Constraint Programming and Mathematical Programming"

Sixiemes Journees Francophones de Programmation par Contraintes JFPC 2010, June 9-11, 2010, Caen, France

Improving Constraint Modelling Using Visualization (Presentation) (Abstract) Invited Talk

SAIS/SweConsNet, May 20/21, 2010, Uppsala, Sweden

CPTV - Generating Personalized TV Schedules (Presentation) Invited Talk at the Swedish AI Society Meeting 2010

VIZ - A Generic Constraint Visualization Tool (Presentation) with P. Davern, presented at the SweConsNet Meeting 2010

New Papers

A Generic Visualization Platform for CP with Paul Davern, Jacob Feldman, Deepak Mehta, Luis Quesada and Mats Carlsson

A Resource Cost Aware Cumulative with Tarik Hadzic

1st Annual Irish Collegiate Programming Contest

Group Photo

UCC Boole Lecture 2009: Peter Norvig

Gene Freuder and Peter Norvig

CP 2009, Lisbon, September 2009

A Hybrid Constraint Model for the Routing and Wavelength Assignment Problem (Presentation) Watch the Trailer! Best Application Paper Award CP 2009

SYMCON 09 - Ninth International Workshop on Symmetry and Constraint Satisfaction Problems (CP2009)

Symmetry Breaking by Local Search - S. D. Prestwich, B. Hnich, H. Simonis, R. Rossi, and S. A. Tarim

SPARK 09 - Scheduling and Applications Workshop (ICAPS 2009), September 2009

Scheduling in the Real World: Lessons Learnt - R. van der Krogt, J. Little and H. Simonis

Association for Constraint Programming Summer School 2009

Example Slide

This is a self-study course on constraint programming using the ECLiPSe language. The course consists of video lectures, slides, handouts and other material. The slides have been updated for the course, the video lectures are not using the latest slide versions.

Group Photo ACP Summer School 2009

CSCLP 2009, Barcelona, June 2009

Invited Talk: Lessons Learned from Developing an On-line Constraint Programming Course (Abstract) Presentation (PDF)

Solving the Static Design Routing and Wavelength Assignment Problem Presentation (PDF)

Shikaku as a Constraint Problem Presentation (PDF)

CP-AI-OR 2009 Masterclass: Modelling in Constraint Programming

Slides (100Mb) Handout (2 slides per page)

CP-AI-OR 2009, Pittsburgh, May 2009

Progress on the Progressive Party Problem. (Extended Abstract) Slides (PDF)

Algodec Doctoral School

Group Photo Algodec Doctoral School


Panorama of Sydney

Pictures from CP2008 Sydney, Australia Index Sheet
Search Strategies for Rectangle Packing. H. Simonis and B. O'Sullivan. CP 2008 Application Track. Download PDF Slides Watch the Trailer!
Kakuro as a Constraint Problem MODREF08, Sydney Australia, September 2008 Download PDF Slides


These are older publications for which I still have electronic draft versions, available for download here. The published, final versions will differ slightly, but are not available for download from this website due to copyright restrictions.

Book Chapters

Search-Tree Visualization DiSCiPl book Download PDF
Complex Constraint Abstraction: Global Constraint Visualization DiSCiPl book Download PDF
Using Constraint Visualization Tools DiSCiPl book Download PDF
Constraint Applications in Networks Handbook of Constraint Programming Download PDF
Building Industrial Applications with Constraint Programming CCL-2 Combination of Computational Logics Download PDF

Journal Articles

TACT An Integrated Transportation Problem Solved with CHIP IEEE Intelligent Systems and their Applications Download PDF
Models for Global Constraint Applications Constraints, 2007 Download PDF
Constraint Satisfaction Using Constraint Logic Programming Artificial Intelligence, 1992 Download PDF


Solving the Car Sequencing Problem in Logic Programming ECAI 1988 Download PDF
APACHE - A Constraint Based, Automated Stand Allocation System ASTAIR 1991 Download PDF
Modelling Producer/Consumer Constraints CP 1995 Download PDF
Building Industrial CHIP Applications from Reusable Software Components PAP95 Download PDF
L' apport des contraintes globales pour la modelisation et la resolution d'applications industrielles FRANCORO 1998 Download PDF
Challenges for Constraint Programming in Networking CP2004 Download PDF
Primary/Secondary Path Generation Problem: Reformulation, Solutions and Comparisons ICN2005 Download PDF
Constraint Based Resilience Analysis CP2006 Download PDF
Presentation PDF

Workshops etc

The Use of Exclusion Constraints to Handle Location Continuity CP Workshop ILPS 1994 Download PDF
A Problem Classification Scheme for Finite Domain Constraint Programming Modelling Workshop CP1996 Download PDF
Calculating Lower Bounds on a Resource Scheduling Problem CP Workshop ASIAN 1996 Download PDF
A Note on CSPLIB prob007 CSPLIB007 Download PDF
Cutting Stock Revisited COSYTEC TR, 1999 Download PDF
News on Producers and Consumers COSYTEC TR, 1999 Download PDF
Blend Optimization inside FORWARD - Constraint Hierarchies and Relaxation on a Real-life Example COSYTEC TR, 1994 Download PDF


Constraint Logic Programming KIFS95 Download PDF
Scheduling and Planning with Constraint Logic Programming PAP95 Download PDF
A Problem Classification Scheme - When to use CLP PACT96 Download PDF
Standard Models for Finite Domain Constraint Solving PACT97 Download PDF
Standard Models Two for Finite Domain Constraint Solving PACT98 Download PDF
Visualization in Constraint Logic Programming PACLP99 Download PDF
Finite Domain Constraint Programming Methodology PACLP2000 Download PDF
Developing Applications with ECLiPSe IC-Parc 2003-2 Download PDF
Nurse Rostering with Constraint Programming - An Overview EPSRC Interdisciplinary Scheduling Network Workshop on Rostering of Hospital Medical Staff Download PDF
Constraint Applications Using Graph Theory Results CP-AI-OR 2004 Download PDF
Bibliography PDF

CHIP Visualization Website

Interactive Website on Constraint Debugging and VisualisationStart Website


A Note on Perfect Square Placement CSPLIB prob009 Download PDF
Square Placement Variants DiSCiPl workshop 98 Presentation PDF
Generalized Euler's Knight unpublished Download PDF
Sudoku as a Constraint Problem Modelling Workshop CP2005 Download PDF
Kakuro as a Constraint Problem Modref 2008 Download PDF
A Tale of Two Puzzles unpublished Presentation PDF
Dominoes as a Constraint Problem unpublished Download PDF
Shikaku as a Constraint Problem CSCLP 2009 Download PDF


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