Knowledge Representation and Reasoning

Welcome to the newly established group headed by Johannes (P.) Wallner, specializing on Knowledge Representation & Reasoning (KRR).

If you are interested in student topics (e.g., for a Bachelor's or Master's thesis) you can have look at the topics page. A Bachelor's or Master's thesis can be started anytime (contact).

Broadly construed, knowledge representation & reasoning in Artificial Intelligence is concerned with foundational research questions such as how to represent knowledge and how to reason based on knowledge. Our research and teaching focuses on

  • formal studies of prominent logic-based representations of knowledge, and
  • addressing challenging computational reasoning tasks arising in KRR.

Our research agenda is to further understanding of complex forms of reasoning in knowledge representation, and to bring promising approaches closer to application, by going from theory to practice.

One of our main current areas is computational argumentation. For a general introduction to the topic, you can have a look, e.g., at the Handbook of Formal Argumentation or this article

** News **: Call for applications to the Doctoral Consortium (DC) of KR'24.

** New course **: Logic-based Knowledge Representation (winter term).

Below you find recent news (news archive).

Recent News


Paper accepted to LPNMR

5.9.2024

Our work "A Semantical Approach to Abstraction in Answer Set Programming and Assumption-based Argumentation" was accepted to this year's edition of LPNMR. Following the theme of the conference, non-monotonic reasoning and logic programming, we investigate forms of abstractions on logic programs under the answer set semantics and on the related assumption-based argumentation formalism.


Invitation to Early Career Track at IJCAI 2024

15.07.2024

At IJCAI 2024, Wallner will present recent works on the topic of "Computational Argumentation: Reasoning, Dynamics, and Supporting Explainability" in the Early Career track of the conference, which is a by invitation only track. In this talk, an overview of recent advances of algorithmic approaches to argumentative reasoning including static and dynamic forms is given, and ways of supporting explainability are discussed.


Three papers accepted to KR 2024

11.07.2024

In this year's edition of the International Conference on Principles of Knowledge Representation and Reasoning (KR'24), three of our works got accepted:

  • Complexity Results and Algorithms for Preferential Argumentative Reasoning in ASPIC+
  • Abstraction in Assumption-based Argumentation
  • Advancing Algorithmic Approaches to Probabilistic Argumentation under the Constellation Approach

In the first work, we extend computational approaches to the prominent structured argumentation formalism of ASPIC+, in particular incorporating also preferential argumentative reasoning. In the second work we deal with abstracting information to attain a high-level view aimed at supporting explainability. In the third work we studied alorithmic approaches to the highly complex field of probabilistic reasoning in formal argumentation.


Invited Talk at TU Wien

9.7.2024

Wallner gave an invited talk at the Workshop on Recent Trends in Formal Argumentation at TU Wien on the topic "Instantiations and Computational Aspects of Assumption-based Argumentation". This workshop discussed recent advances in the field of computational argumentation. 


Three papers accepted to COMMA 2024

14.06.2024

Three of our works are accepted to COMMA 2024, a conference dedicated to computational argumentation. In the first work "Value-based Reasoning in ASPIC+" we investigate how value-based reasoning can be integrated in the argumentation formalism ASPIC+. In "On Computing Admissibility in ABA" we look at algorithmic approaches that compute compact representations of admissible sets of arguments in non-flat assumption-based argumentation. In the third work, "Complexity of Semi-Stable Semantics in Abstract Dialectical Frameworks", we extend the current state-of-the-art complexity analysis on abstract dialectical frameworks, by considering the recently introduced semi-stable semantics.  


Papers accepted to IJCAI 2024 and RATIO 2024

2.5.2024

Our works on "Ranking Transition-based Medical Recommendations using Assumption-based Argumentation" and "Instantiations and Computational Aspects of Non-Flat Assumption-based Argumentation" have been accepted to RATIO and IJCAI 2024, respectively. RATIO is a new conference on advances in argumentation machines and IJCAI is a premier conference in Artificial Intelligence. 

In the first work we look at using a ranking-based semantics for assumption-based argumentation in a medical scenario. In the second work we look at issues arising when creating argument structures from a possibly conflicting knowledge base. We consider algorithmic approaches to address the issues.