• 22 Sept 2021:The deadline for the Special Issue on Multi-Objective Decision Making in JAAMAS has been extended to 01-Dec-2021.
  • 06 July 2021: The MODeM 2021 Discord server is now live:
  • 14 June 2021: We are excited to annouce Ali E. Abbas as the first keynote speaker for MODeM 2021.
  • 14 June 2021: MODeM 2021 recieved a total of 10 submissions.
  • 17 May 2021: The deadline for submissions for MODeM 2021 has been extended to 7 June 2021
  • 19 April 2021: MODeM 2021 has been added to the list of endorsed events by the International Society on Multiple Criteria Decision Making
  • 23 March 2021: MODeM Workshop twitter account launched. Follow us @modem_workshop
  • 22 March 2021: MODeM 2021 site launched

Multi-Objective Decision Making Workshop - 2021

In recent years there has been a growing awareness of the need for automated and assistive decision making systems to move beyond single-objective formulations when dealing with complex real-world issues, which invariably involve multiple competing objectives. The purpose of this workshop is to promote collaboration and cross-fertilisation of ideas between researchers working in different areas of multi-objective decision making and on the topics of interest below, and to provide a forum for dissemination of high-quality multi-objective decision making research.

The workshop targets high-quality original papers covering all aspects of multi-objective decision making, including, but not limited to, the list of topics below. The following is a non-exhaustive list of topics that we would like to cover in the workshop:

  • Multi-objective/multi-criteria/multi-attribute decision making
  • Multi-objective reinforcement learning
  • Multi-objective planning and scheduling
  • Multi-objective multi-agent decision making
  • Multi-objective game theory
  • Preference elicitation for MODeM
  • Social choice and MODeM
  • Multi-objective decision support systems
  • Multi-objective metaheuristic optimisation (e.g. evolutionary algorithms) for autonomous agents and multi-agent systems
  • Multi-objectivisation
  • Explainable MODeM
  • Applications of MODeM
  • New benchmark problems for MODeM

Extended and revised versions of papers presented at the workshop will be eligible for inclusion in a journal special issue (see below).

Program Details

The workshop programme will be spread over 3 days from 14th to 16th July, consisting of contributed original talks, invited talks, and a panel discussion. Each day’s live session will be restricted to 2 hours duration, and scheduled to maximise opportunities for global participation. Presentations will also be recorded and available outside of these sessions, with a dedicated Discord channel for discussing each paper before, during and after the workshop. Extended and revised versions of papers presented at the workshop will be eligible for inclusion in a journal special issue (see below).

Important Dates

  • Submission Deadline: 31 May 2020   extended to 7 June 2021 by 23:59 BST-12
  • Notification of acceptance: 30 June 2021
  • Camera-ready copies: 7 July 2021
  • Workshop: 14, 15 & 16 July 2021

Submission Details

Papers should be formatted according to the AAMAS 2021 guidelines, and should be a maximum of 8 pages in length (with additional pages containing references only). Shorter papers reporting preliminary results and work-in-progress are also welcome. Submissions should report original work that has not previously been published elsewhere.

All submissions will be peer-reviewed (single-blind). Accepted work will be allocated time for poster and possibly oral presentation during the workshop.

Papers can be submitted through Easychair.

When preparing your submission for MODeM 2021, please be sure to remove the AAMAS copyright block, citation information and running headers. Please replace the AAMAS copyright block in the main.tex file from the AAMAS template with the following:

\acmConference[MODeM '21]{Proc.\@ of the 1st Multi-Objective Decision Making Workshop (MODeM 2021)}
{July 14-16, 2021}{Online, \url{}}{Hayes, Mannion, Vamplew (eds.)}


Journal Special Issue

After the workshop, all original contributions presented at MODeM 2021 will be invited to submit substantially improved and extended versions of their work, for consideration to be published in a post-proceedings journal special issue of JAAMAS.


Submission of preliminary work to the MODeM 2021 workshop does not confer an automatic entitlement to publish in the JAAMAS MODeM special issue; all special issue submissions must pass through the same rigorous JAAMAS review process and meet the standard JAAMAS publication criteria.

The JAAMAS MODeM special issue has an open call for papers; it is not necessary to submit preliminary work to the MODeM 2021 workshop in order to have your manuscript considered for publication in this special issue. The special issue is already open for submissions, and will remain open until December 1, 2021. Papers submitted to the special issue will be sent out for peer review as soon as they are received, and first decisions can be expected within 2 months approx.

Discord Server

MODeM 2021 will run online via Discord. The link to the MODeM 2021 Discord server can be found here: The Discord server is now live!

Each paper accepted to MODeM 2021 has a designated text channel, where the video presentation and slides for each paper will be posted. We encourage all MODeM 2021 attendees to ask questions via the text channels. The authors will be monitoring their text channel and will respond to questions. Each technical session also has a designated voice channel, where the panel discussions, keynote talk and live paper presentations will take place. We ask all attendees to use the voice channels to view all live content.

Each session will run on the Discord server as per the outlined MODeM 2021 program schedule.


Opening Session: Wednesday 14 July 20:00 - 22:00 BST
Session Chair: Roxana Rădulescu (Vrije Universiteit Brussel)

20:00 - 20:05 BST Welcome & Opening Remarks
20:05 - 21:00 BST Invited Talk: Ali E. Abbas (University of Southern California)
Constructing Multiattribute Utility Functions: Past, Present and Future Opportunities
21:00 - 22:00 BST Panel Discussion
Topic: Challenges and Opportunities for Real-World Applications of MODeM
Chair: Roxana Rădulescu (Vrije Universiteit Brussel)
  • Ali E. Abbas (University of Southern California)
  • Timothy Atkinson (NNAISENSE)
  • Ann Nowé (Vrije Universiteit Brussel)
  • Marcello Restelli (Politecnico di Milano)

Technical Session 1: 15 July 20:00 - 22:30 BST
Session Chair: Pieter Libin (Hasselt University)

20:00 - 20:30 BST Benjamin Smith, Robert Klassert and Roland Pihlakas
Research Paper: Soft maximin approaches to Multi-Objective Decision-making for encoding human intuitive values
20:30 - 21:00 BST Patrick Mannion, Fredrik Heintz, Thommen George Karimpanal and Peter Vamplew
Position Paper: Multi-Objective Decision Making for Trustworthy AI
21:00 - 21:30 BST Federico Toffano and Nic Wilson
Research Paper: Preference Learning for Horizontal Collaboration in Transport Operations
21:30 - 22:00 BST Xavier Gandibleux, Guillaume Gasnier and Said Hanafi
Research Paper: A primal heuristic to compute an upper bound set for multi-objective 0-1 linear optimisation problems
22:00 - 22:30 BST Jaeyoung Lee, Sean Sedwards and Krzysztof Czarnecki
Research Paper: Recursive Constraints to Prevent Instability in Constrained Reinforcement Learning

Technical Session 2: 16 July 20:00 - 22:00 BST
Session Chair: Johan Kallström (Linköping University)

20:00 - 20:30 BST Diederik M. Roijers, Willem Röpke, Ann Nowé and Roxana Rădulescu
Research Paper: On Following Pareto-Optimal Policies in Multi-Objective Planning and Reinforcement Learning
20:30 - 21:00 BST Federico Malerba and Patrick Mannion
Research Paper: Evaluating Tunable Agents with Non-Linear Utility Functions under Expected Scalarised Returns
21:00 - 21:30 BST Mathieu Reymond, Conor F. Hayes, Diederik M. Roijers, Denis Steckelmacher and Ann Nowé
Research Paper: Actor-Critic Multi-Objective Reinforcement Learning for Non-Linear Utility Functions
21:30 - 22:00 BST Willem Röpke, Diederik M. Roijers, Ann Nowé and Roxana Rădulescu
Research Paper: On Nash Equilibria for Multi-Objective Normal Form Games under Scalarised Expected Returns versus Expected Scalarised Returns

Invited Talk

Ali E. Abbas

Affiliation: University of Southern California, USA


Talk Title: Constructing Multiattribute Utility Functions: Past, Present, and Future Opportunities and Challenges

Abstract: The field of multiattribute utility theory spans a wide range of applications including healthcare, climate change, game theory, AI, and automated decision support. The elicitation of a representative multiattribute utility function is therefore an essential task in the analysis of many decisions. As the number of attributes increases, however, the construction of the utility function poses many cognitive challenges and several methods have been proposed to simplify the elicitation task. This talk discusses some of the classic approaches to constructing multiattribute utility functions and discusses the opportunities and challenges they entail. The talk also discusses recent methods for constructing utility functions that overcome some of the limitations used in classic approaches.

Bio: Dr. Ali E. Abbas is Professor of Industrial and Systems Engineering and Public Policy at the University of Southern California. He is author and co-author of numerous books including “Foundations of Decision Analysis” with Ronald A. Howard, “Foundations of Multiattribute Utility”, and “Next-Generation Ethics: Engineering a Better Society”. The recipient of multiple awards from the National Science Foundation for his work, Dr. Abbas’ research focuses on decision analysis, risk analysis, multiattribute utility theory, and data-based decision making. Dr. Abbas serves on the editorial boards of numerous journals including Operations Research, Decision Analysis, Decision, and Entropy. He is widely published in books, journals, and conference publications, and has shared his expertise through television appearances, TEDx and other invited talks. In addition to his academic career, Dr. Abbas has been on the Advisory Boards of numerous corporations including Hedgestreet Inc., a binary futures exchange, and the Decision Education Foundation, a nonprofit organization that empowers youth to make better decisions about their lives. He is also is founder of the decision-making social network, Ahoona Corp, that spreads decision making tools to society and has several thousand users around the world. Dr. Abbas also has extensive consulting and management experience.

Program Committee

  • Timothy Atkinson, NNAISENSE S.A., CH
  • Gabriel de Oliveira Ramos, Universidade do Vale do Rio dos Sinos, BR
  • Debora Di Caprio, University of Trento, IT
  • Madalina Drugan, ITLearns.Online, NL
  • Fredrik Heintz, Linköping University, SE
  • Athirai A. Irissappane, University of Washington (Tacoma), US
  • Johan Källström, Linköping University, SE
  • Thommen Karimpanal George, Deakin University, AU
  • Pieter Libin, Hasselt University, BE
  • Maite Lopez-Sanchez, Universitat de Barcelona, ES
  • Thibaut Lust, Sorbonne Université, FR
  • Frederico Malerba, University of Potsdam, DE
  • Karl Mason, National University of Ireland Galway, IE
  • Abdel-Illah Mouaddib, Université de Caen Normandy, FR
  • Simone Parisi, Facebook AI Research, US
  • Roxana Rădulescu, Vrije Universiteit Brussel, BE
  • Mathieu Reymond, Vrije Universiteit Brussel, BE
  • Manel Rodriguez-Soto, Artificial Intelligence Research Institute (IIIA-CSIC), ES
  • Sandhya Saisubramanian, University of Massachusetts Amherst, US
  • Francisco Javier Santos-Arteaga, Free University of Bolzano, IT
  • Nic Wilson, University College Cork, IE
  • Luisa M. Zintgraf, University of Oxford, UK
  • Yijie Zhang, University of Copenhagen, DK


This year's workshop is organised by: Senior Advisory Committee:


If you have any questions about the MODeM workshop, please contact the organizers at:
modem.workshop.2021 AT