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Artificial Intelligence and Knowledge Representation

Research in Artificial Intelligence at DIAG started in the early 80s and established this research group as one of the most prominent ones in the field of logic-based knowledge representation and automated reasoning. Research has been conducted in many areas, with several outstanding results. The research lines presently active are described in the following.

Description Logics (DL) form a family of Logic-based Knowledge Representation Languages which allow for modeling an application domain in terms of objects, concepts and relationships between concepts, and for reasoning about them. They are widely used in several areas, including ontology engineering, Semantic Web, and information integration. The research at DIAG on DL has a long tradition, and focuses on many relevant aspects, including algorithms for automated reasoning, trade-off between expressive power and computational complexity of reasoning, query answering in DL knowledge bases, adding both monotonic and non-monotonic rules to DL. In the future, the work on DL will both continue along the above mentioned lines and focus on dynamic aspects, such as update and revision of DL knowledge bases, and reasoning about programs expressed on such knowledge bases.

The Semantic Technologies aim at intelligent information processing by creating and connecting machine-understandable information, sometimes called the Semantic Web. Our research in this area mainly focuses on representation languages, in particular for ontologies. A remarkable outcome of our research in this area is the standardization of the OWL 2 QL ontology specification language by the World Wide Web Consortium. OWL 2 QL directly derives from DL-Lite, a family of ontology formalisms which we proposed and studied in our recent research in this field.

Reasoning about Actions concerns the theory and the implementation of agents that reason, act and perceive in changing, incompletely known, and unpredictable environments. Such agents must have higher level cognitive functions that involve reasoning, for example, about goals, actions, when to perceive and what to look for, the cognitive states of other agents, time, collaborative task execution, etc. Our research on Reasoning about Actions focuses on several aspects, including: foundations of theory of actions; various forms of planning or automated process synthesis for sophisticated dynamic properties, e.g., expressed in mu-calculus, ATL, LTL, LTLf, and LDLf; high-level agent programs, like ConGolog based on the Situation Calculus; agent behavior synthesis and composition.  This research is also related with, and applied to, other areas, such as cognitive robotics, multi-agent/multi-robot systems, software service modeling, execution and composition, high-level programs and business processes over ontologies and data sources.

One specific application where knowledge representation has been applied is Spoken Language Understanding in the context of Robotics. Specifically, we have addressed the interpretation of spoken commands and the extension to handle more complex forms of dialog.  The knowledge about the environment and the robot capabilities are used by the system in order to build the language that specifies robot commands. Moreover, the knowledge about the environment (semantic map), can be used to bias the interpretation of commands through a spoken language command interpretation chain that is based on statistical off-the-shelf tools.

Finally, the group also investigates the synergistic integration of Natural Language Processing and Knowledge Representation.

Several group members are recipients of prestigious awards,  are regularly involved in editorial activities of the scientific community, and are invited to deliver keynote talks at international conferences or workshops.

Awards and honours include: 

  • AAAI Fellowships: Maurizio Lenzerini, since 2017; Giuseppe De Giacomo, since 2016; Luigia Carlucci Aiello, since 1995.
  • EurAI Fellowships: Riccardo Rosati, since 2016, Giuseppe De Giacomo, since 2012,  Daniele Nardi, since 2009, Maurizio Lenzerini, since 2008; Luigia Carlucci Aiello, since 1999.
  • Membership to the European Academy of Sciences and Arts (Luigia Carlucci Aiello, since 2005).
  • ACM Fellowships (Maurizio Lenzerini, since 2009; Giuseppe De Giacomo, since 2016).
  • Membership to the Academia Europaea --The Academy of Europe (Maurizio Lenzerini, since 2011).
  • IJCAI Distinguished Service Award (Luigia Carlucci Aiello, 2009).
  • ECCAI Distinguished Services Award (Luigia Carlucci Aiello, 2014).
  • Doctorate Honoris Causa (Luigia Carlucci Aiello, 2002, School of Technology, University of Linkoping, Sweden).
  • ACM Recognition Service Award (Maurizio Lenzerini, 2011).
  • Fabio Patrizi was awarded the ICDT Test of Time Award 2019 for the paper A. Deutch, Richard B. Hull, F. Patrizi, V. Vianu: Automatic verification of data-centric business processes (ICDT 2009).

In 2021, several group members have been involved in various prestigious editorial activities:

  • Giuseppe De Giacomo has been Associate Program Chair of the 30th International Joint Conference on Artificial Intelligence (IJCAI), he has been local organizer of the 18th International Conference on Principles of Knowledge Representation and Reasoning, he is an honorary member of the Steering Committee Member of the International Conference on Principles of Knowledge Representation and Reasoning (KR). He is also involved in the EU-ICT-48 TAILOR as the work-package leader of WP5: "Deciding and Learning How to Act";
  • Domenico Lembo is vice-president (2018-2021) of the Steering Committee of the International Conference on Web Reasoning and Rule Systems (RR)
  • Maurizio Lenzerini is Area Editor of Information Systems -- An International Journal, for the area of Data Modeling and Knowledge Representation and Reasoning Techniques, Editorial Board member of Intelligenza Artificiale, The International Journal of the AI*IA,  Area Editor of the Journal of Applied Logic for the area of Logic for Knowledge Representation and the Semantic Web, Editorial Board member of the Logical Methods in Computer Science (LMCS)  Journal, for the areas of Database Theory and Logic for Knowledge Representation,  and Area Editor of the Logic Journal of the Interest Group in Pure and Applied Logic (IGPL), for the area of Logic for Knowledge Representation and the Semantic Web, he has been co Chair of the 29th International Workshop on Description Logics (DL 2016), since 2011 he is  Member of the ACM SIGMOD Awards Committee, since 2006 he is Member of the Executive Committe of the ACM Principles of Database Systems (PODS), and since 2005 he is Member of the Sistemi Evoluti di Basi di Dati (SEBD) Steering Committe, he is also Member of the Scientific Advisory Board of BiCi --Bertinoro international Center for Informatics and Member of the Advisory Board of the European Research Institute in Service Science (ERISS).
  • Roberto Navigli has been appointed as Action Editor of Transactions of the ACL and ACL Rolling Review.
  • Riccardo Rosati is Member of the Editorial Board of Artificial Intelligence (Elsevier), Steering Committee Member of the International Workshop on Nonmonotonic Reasoning (NMR), since 2012.

Finally, the following invited talks were delivered: 

  • Giuseppe De Giacomo: "Reactive Synthesis, Planning and Reinforcement Learning in the Finite Trace Setting”, keynote at Third International Workshop on Formal Methods in Artificial Intelligence, April 16, 2021, Imperial College London, UK
  • Giuseppe De Giacomo, Marco Favorito, Alessandro Ronca: "WhiteMech Research on Merging Reasoning and Learning in Autonomous Agents”, invited talk at Universitat Pompeu Fabra, Barcelona (online) June 17, 2021
  • Giuseppe De Giacomo: "Reactive Synthesis, Planning and Reinforcement Learning in Linear Temporal Logic on Finite Traces”, keynote at ESSLLI 2021 Workshop on Automated Synthesis, Utrecht, Netherlands (online), July 30, 2021
  • Giuseppe De Giacomo: "Artificial Intelligence-based Declarative Process Synthesis for BPM”, keynote at the 19th International Conference on Business Process Management, BPM 2021, Rome, September 9, 2021, 2021
  • Giuseppe De Giacomo: "Autonomy in AI Reasoning and Learning in Autonomous Agents”, invited talk at Rice University, Houston, TX, USA, September 16, 2022
  • Giuseppe De Giacomo: "Autonomy in AI: Reactive Synthesis, Planning and Reinforcement Learning in Linear Temporal Logic on Finite Traces”, keynote at 44th German Conference on Artificial Intelligence, Berlin, Germany (online), October 1, 2021
  • Giuseppe De Giacomo: "Resilience-based Generalized Planning and Strategic Reasoning”, JPMorgan AI Faculty Research Award Talk, New York, NY, USA (online), November 6, 2021
  • Giuseppe De Giacomo, Alessandro Ronca: "WhiteMech Research on Merging Reasoning and Learning in Autonomous Agents”, invited talk at University of Oxford, UK, (online) November 25, 2021
  • Fabio Patrizi: "LTLf -based Trace Alignment: a Planning-based Approach", invited talk at University of Melbourne, VIC (AU) Agents-VIC, (online) May 2021 


  • PRIN2020: "Resilient AI-Based Self-Programming and Strategic Reasoning (RIPER)”,  PI: Giuseppe De Giacomo, Total funds: 988.995 Euros, Funds to Sapienza 275.000. starts in June 2022
  • JPMorgan AI Faculty Research Award 2021 “Resilience-based Generalized Planning and Strategic Reasoning” 90000 USD
  • Tailor: Foundations of Trustworthy AI - Integrating Reasoning, Learning and Optimization (No. 952215), September 2020 - August 2023, PI Maurizio Lenzerini
  • Bubbles: Defining the BUilding Basic BLocks for a U-Space SEparation Management Service (No. 893206), May 2020 - October 2022, PI Luca Iocchi.
  • WhiteMech: White-box Self-Programming Mechanisms, ERC Advanced Grant (No. 834228), November 2019 - October 2024, PI Giuseppe De Giacomo.
  • Controlled Query Evaluation in Ontology-based Data Management Systems, Sapienza Università di Roma,  11/12/2019 - 10/12/2022, PI Domenico Lembo
  • MOUSSE: Multilingual Open-text Unified Syntax-independent SEmantics (no. 726487), ERC Consolidator Grant, June 2017 - May 2023, PI Roberto Navigli
  • ELEXIS: European Lexicographic Infrastructure (no. 731015), Excellent Science - EU Research Infrastructure, February 2018 - July 2022, PI Roberto Navigli
  • PerLIR: Personalized LInguistic Resources & PI - Italian PRIN (Progetti di Rilevanza Nazionale), PI Roberto Navigli
  • DRAPE: Data-awaRe Automatic Process Execution, Sapienza Università di Roma, 28/02/2019 - 27/02/2022, PI Fabio Patrizi 


  • Yves Lesperance (first visit) June 23, 2021 to September 3, 2021
  • Yves Lesperance (second visit) November 8, 2021 to January 7, 2022
  • Brian Logan, October 11, 2021 to October 16, 2021
  • Natasha Alechina, October 11, 2021 to October 16, 2021
  • Eugenia Ternovska, November 14, 2021 to November 19, 2021


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