Foundations of Artificial Intelligence (FAI) Group
Prof. Dr. Jörg Hoffmann
Saarland Informatics Campus
Foundations of Artificial Intelligence Group
Building E1 1
66123 Saarbrücken, Germany
(last name) (at) cs (dot) uni-saarland (dot) de
+49 (0) 681 302 71471
+49 (0) 681 302 57554
Consultation hour (Sprechstunde): Wednesdays, 9:30 -- 10:30.
Own publications page (with PDF
Research Interests. I'm interested in a range of topics
relating to problem solving, more specifically to the modeling and
solution of combinatorial search problems. My main field of expertise
is Automatic Planning, a sub-area of AI concerned with decision making
problems (my planning
lecture describes this in a little more detail). I am also
conducting research in various related areas, including SAT/CP, model
checking, semantic web services, business process management, markov
decision processes, natural language sentence generation, and
simulated network security penetration testing.
For a detailed summary of my current research lines, please see
the FAI group's Research page.
Short CV. I received a diploma in computer science from the
University of Freiburg in March 1999, and completed my PhD at the same
University in July 2002, with a thesis that won
Dissertation award 2002. I stayed on as a Postdoc until August
2004. From September 2004 until April 2006, I worked at Max Planck
Institute for Computer Science Saarbruecken. In summer 2006 I was a
Visiting Scientist at Cornell University, after which I worked at the
University of Innsbruck where I obtained my Habilitation in CS. I
joined SAP Research Karlsruhe in April 2008, and I joined INRIA Nancy
as a Directeur de Recherche in October 2009. I became a Professor at
Saarland University in April 2012, where I'm heading the
Foundations of Artificial Intelligence
- Runner-Up in the sequential agile track and in the sequential
bounded-cost track. Both with SaarPlan, at
the 2018 International Planning Competition.
- Best Paper Award at the 25th
International Symposium on Model Checking of Software (SPIN'18).
- Outstanding Senior Program Committee (SPC) Member Award
2017 Influential Paper Award, Honorable Mention (with Ronen
2016 Outstanding Student Paper Award (with Jeanette Daum, Alvaro
Torralba, Patrik Haslum, and Ingo Weber).
- Runner-Up in the sequential satisficing track (best-performing
basic, i.e., non-portfolio, solver); Innovative Planner Award. Both
with Michael Katz, at
International Planning Competition.
- Busy Beaver Award for
Planning lecture, as the best winter 13-14 core/advanced
course. Awarded each teaching term by the Saarland University CS
2013 Best PC Member Award.
2013 Influential Paper Award (with Julie Porteous and Laura
2012 Best Paper Award (with Emil Keyder and Patrik Haslum).
of the optimal track at the 7th International Planning Competition
(IPC'11), with Fast Downward Stone-Soup (1st prize) and
Merge-and-Shrink (2nd prize).
- Nominated for ICAPS 2011 Best Paper Award.
- Chaire d'Excellence project grant by the French Agence Nationale
de Recherche (ANR), selected as one of 15 accepted proposals in a
nationwide call across all scientific disciplines.
2008 Influential Paper Award, Honorable Mention (with Jana
Koehler, Bernhard Nebel, and Yannis Dimopoulos).
2007 Best Research Paper Award (with Malte Helmert and Patrik
- Nominated for IJCAI 2007 Best Paper Award (with Carla Gomes,
Ashish Sabharwal, and Bart Selman).
of the optimal track at the 5th International Planning Competition
(IPC'06), with SATPLAN.
- Nominated for ICAPS 2006 Best Paper Award (with Ashish Sabharwal
and Carmel Domshlak).
- IJCAII-JAIR Best
Paper Prize 2005 (with Bernhard Nebel).
- AAAI 2005 Outstanding PC Member Award.
2004 Best Paper Qward (with Ronen Brafman).
Dissertation Award 2002. Award for the best European Dissertation
in the field of AI. Awarded annually by ECCAI, the European
Coordination Committee for Artificial Intelligence.
- Winner of the
fully-automated track at the 2nd International Planning Competition
(IPC'00), with FF.
of the ADL track at the 1st International Planning Competition
(IPC'98), with IPP.
Please see the FAI Teaching page.
Attention lecturers! The lecture slide sources for the
AI and Planning courses are available on request. Just email
A central activity in my research area is the development of systems,
whose empirical performance serves to evaluate the underlying
ideas. Here 's a list of systems I've been involved in:
For more detailed information and source code downloads, please see
the FAI group's Software page.
- IPP. This
is a planning tool I implemented as a student. It is based on the
Graphplan algorithm and nowadays largely outdated.
- FF. This planning tool was started in my
PhD thesis, and gained fame by outclassing the competition in the 2000
International Planning Competition (IPC), setting a completely new
standard in planner performance. The tool is still widely used today;
variants of its key techniques are used in almost every state of the
art planner. FF has been extended to several expressive variants of
planning, implemented in the tools Metric-FF (numeric state
variables), Conformant-FF (uncertain initial states), Contingent-FF
(partial observability), and Probabilistic-FF (like Conformant-FF but
with probabilistic initial states and action effects).
- SATPLAN. This
planner, originally proposed by Henry Kautz and Bart Selman, compiles
planning into a series of SAT problems. It has long dominated the
track for optimal planning tools at the IPC. My contribution amounted
to implementation works on encoding planning into SAT.
- UPPAAL. This is a very
widely used tool for model checking networks of timed automata. With
co-workers at the Ujniversity of Freiburg, I adapted planning
heuristic functions to this context, and showed that they can be
useful to more effectively find bugs (paths to undesired states) in
the state spaces of such networks.
- TorchLight is a recent tool I
have developed, which allows to analyze search space topology without
actually running any search. The tool applies to planners based on the
"ignoring delete lists" relaxation.
- adl2strips translates input from the
ADL planning language, which allows arbitrary first-order formulas in
operator preconditions and the goal, to the simpler STRIPS language
which restricts these to conjunctions of atoms. The tool also features
two methods for compiling away conditional effects. It has been used
in the 2004 IPC, and in some later editions of the IPC as well.
Downward. This planning tool was started in the PhD thesis of
Malte Helmert, and has in the meantime evolved into the main platform
for implementing and evaluating planning algorithms. Fast Downward
implements a great variety of search techniques based on heuristic
search (including those of FF). The FAI group are regular
contributors, devising for example some of the techniques
-- merge-and-shrink abstractions, a method to compute lower
bound heuristic functions to be used for optimal planning -- that were
awarded in the 2011 IPC versions of Fast Downward.
- Associate Editor
- Associate Editor
(Journal of Artificial Intelligence Research).
- Area Chair for Planning
of AI Communications, the
European Journal on AI [2009--2012].
- Member of the Senior Program Committees of ICAPS'19, AAAI'19,
IJCAI'18, AAAI'18, IJCAI'17, AAAI'17, IJCAI'16, IJCAI'15, AAAI'15,
ECAI'14, ICAPS'14, IJCAI'13, AAAI'11, ICAPS'11, IJCAI'11, AAAI'10,
ICAPS'09, IJCAI'09, AAAI'08, and AAAI'07.
- Member of the Program Committees of KI'18, SOCS'18, ICAPS'18,
SOCS'17, ICAPS'17, KI'16, SOCS'16, ICAPS'16, AAAI'16, SOCS'15,
ICAPS'15, AAAI'14, WIMS'14, AAAI'13, SOCS'13, ICAPS'13, KR'12,
SOCS'11, KI'11, CPAIOR'09, AIMSA'08, ECAI'08, ICAPS'08, ICAPS'07,
KI'07, SPIN'07, ECAI'06, AAAI'06, ICAPS'06, IJCAI'05, AAAI'05,
ICAPS'05, ICAPS'04, AI&Math'04, ICAPS'03, and AAAI'02.
Co-authors (journal and conference papers).
- Corin Anderson
- Mihai Andrei
- Carlos Areces
- Grigori Babitski
- Gerd Behrmann
- Blai Bonet
- Matthias Born
- Olivier Buffet
- Facundo Bustos
- Simon Bergweiler
- Piergiorgio Bertoli
- Ronen Brafman
- Michael Brenner
- Dunbo Cai
- Luis Costa
- Jeanette Daum
- Vera Demberg
- Henning Dierks
- Yannis Dimopoulos
- Martin Dominguez
- Carmel Domshlak
- Klaus Draeger
- Patrick Dubbert
- Philippe Duchesne
- Stefan Edelkamp
- R. Eifler
- Roman Englert
- Nazim Fates
- Chris Fawcett
- Dieter Fensel
- Alan Fern
- Maximilian Fickert
- Bernd Finkbeiner
- Daniel Fitzner
- Maria Fox
- Hector Geffner
- Alfonso Gerevini
- Daniel Gnad
- Carla Gomes
- Guido Governatori
- Miha Grzar
- Patrik Haslum
- Malte Helmert
- Martin Hepp
- Stijn Heymans
- Holger Hoos
- David Howcroft
- Matthäus Jany
- Michael Katz
- Henry Kautz
- Emil Keyder
- Peter Kissmann
- Eva Klien
- Jana Koehler
- Marek Kowalkiewicz
- Michal Krajnansky
- Sebastian Kupferschmid
- Joel Langlois
- Kim G. Larsen
- Freddy Lecue
- Kevin Leyton-Brown
- Andreas Limyr
- Frederico Liporace
- Alberto Lluch Lafuente
- Derek Long
- Annapaola Marconi
- Ivan Markovic
- Norman May
- Jan Mendling
- Andrew Mitchell
- Bernhard Nebel
- Raz Nissim
- Hector Palacios
- M. Petrick
- Joshua Phillips
- Marco Pistore
- Andreas Podelski
- Valerie Poser
- Julie Porteous
- Thorsten Rauber
- Jussi Rintanen
- Frank Rittinger
- W. Ruml
- Andrey Rybalchenko
- Ashish Sabharwal
- Daniel Schoen
- Laura Sebastia
- Bart Selman
- Ivan Serina
- Adina Sirbu
- Jan-Georg Smaus
- Christoph Stasch
- Michael Stollberg
- Sven Schade
- Guy Shani
- Dorin Shmaryahu
- David Smith
- Fabian Spaniol
- Nathalie Steinmetz
- Francois Tertre
- Sylvie Thiebaux
- Alvaro Torralba
- Mauro Vallati
- Alexander Walkowski
- Ingo Weber
- Martin Wehrle
- Nicolas Zastavni
- Xuan Zhou
Uh yes, I also have hobbies.
Here's the glorious web page of my
Inglorious Mustard Boys ...