Theodore Patkos

FLAP Journal 2025 Journal Article

Social Argumentation Systems

• Antonis Bikakis
• Giorgos Flouris
• Joao Leite
• Theodore Patkos

While a lot of research has been conducted on understanding and formalising the interplay of arguments within the context of Computational Argumentation, this research is not fully applicable to the types of arguments that populate the Social Web. In that context, arguments usually have the form of comments, opinions or reviews, and are the main ingredients of online discussion forums, social networks, online rating and review sites, debate portals and other online communities - the electronic version of word-of-mouth communication. As a result, voting and other forms of reaction to the provided comments or arguments (other than just “attacks”) are allowed, features that are not normally considered in the classical literature on Computational Argumentation. In this chapter, we study extensions of argumentation frameworks that have been proposed to describe and understand the more complex types of interactions among arguments that can be found in the Social Web, and present the current state-of-the-art, as well as open problems.

IJCAI Conference 2021 Conference Paper

Abstract Argumentation Frameworks with Domain Assignments

• Alexandros Vassiliades
• Theodore Patkos
• Giorgos Flouris
• Antonis Bikakis
• Nick Bassiliades
• Dimitris Plexousakis

Argumentative discourse rarely consists of opinions whose claims apply universally. As with logical statements, an argument applies to specific objects in the universe or relations among them, and may have exceptions. In this paper, we propose an argumentation formalism that allows associating arguments with a domain of application. Appropriate semantics are given, which formalise the notion of partial argument acceptance, i. e. the set of objects or relations that an argument can be applied to. We show that our proposal is in fact equivalent to the standard Argumentation Frameworks of Dung, but allows a more intuitive and compact expression of some core concepts of commonsense and non-monotonic reasoning, such as the scope of an argument, exceptions, relevance and others.

KER Journal 2021 Journal Article

Argumentation and explainable artificial intelligence: a survey

• Alexandros Vassiliades
• Nick Bassiliades
• Theodore Patkos

Abstract Argumentation and eXplainable Artificial Intelligence (XAI) are closely related, as in the recent years, Argumentation has been used for providing Explainability to AI. Argumentation can show step by step how an AI System reaches a decision; it can provide reasoning over uncertainty and can find solutions when conflicting information is faced. In this survey, we elaborate over the topics of Argumentation and XAI combined, by reviewing all the important methods and studies, as well as implementations that use Argumentation to provide Explainability in AI. More specifically, we show how Argumentation can enable Explainability for solving various types of problems in decision-making, justification of an opinion, and dialogues. Subsequently, we elaborate on how Argumentation can help in constructing explainable systems in various applications domains, such as in Medical Informatics, Law, the Semantic Web, Security, Robotics, and some general purpose systems. Finally, we present approaches that combine Machine Learning and Argumentation Theory, toward more interpretable predictive models.

KR Conference 2016 Short Paper

A Multi-Aspect Evaluation Framework for Comments on the Social Web

• Theodore Patkos
• Antonis Bikakis
• Giorgos Flouris

Users’ reviews, comments and votes on the Social Web form the modern version of word-of-mouth communication, which has a huge impact on people’s habits and businesses. Nonetheless, there are only few attempts to formally model and analyze them using Computational Models of Argument, which achieved a first significant step in bringing these two fields closer. In this paper, we attempt their further integration by formalizing standard features of the Social Web, such as commentary and social voting, and by proposing methods for the evaluation of the comments’ quality and acceptance.

ECAI Conference 2016 Conference Paper

Symmetric Multi-Aspect Evaluation of Comments - Extended Abstract

• Theodore Patkos
• Giorgos Flouris
• Antonis Bikakis

KER Journal 2015 Journal Article

Resolving conflicts in knowledge for ambient intelligence

• Martin Homola
• Theodore Patkos
• Giorgos Flouris
• Ján Šefránek
• Alexander Šimko
• Jozef Frtús
• Dimitra Zografistou
• Martin Baláž

Abstract Ambient intelligence (AmI) proposes pervasive information systems composed of autonomous agents embedded within the environment who, in orchestration, complement human activity in an intelligent manner. As such, it is an interesting and challenging application area for many computer science fields and approaches. A critical issue in such application scenarios is that the agents must be able to acquire, exchange, and evaluate knowledge about the environment, its users, and their activities. Knowledge populated between the agents in such systems may be contextually dependent, ambiguous, and incomplete. Conflicts may thus naturally arise, that need to be dealt with by the agents in an autonomous way. In this survey, we relate AmI to the area of knowledge representation and reasoning (KR), where conflict resolution has been studied for a long time. We take a look at a number of KR approaches that may be applied: context modelling, multi-context systems, belief revision, ontology evolution and debugging, argumentation, preferences, and paraconsistent reasoning. Our main goal is to describe the state of the art in these fields, and to draw attention of researchers to important theoretical issues and practical challenges that still need to be resolved, in order to reuse the results from KR in AmI systems or similar complex and demanding applications.

EUMAS Conference 2014 Conference Paper

A Dialogical Model for Collaborative Decision Making Based on Compromises

• Dimitra Zografistou
• Giorgos Flouris
• Theodore Patkos
• Dimitris Plexousakis
• Martin Baláz
• Martin Homola
• Alexander Simko

Abstract In this paper, we deal with group decision making and propose a model of dialogue among agents that have different knowledge and preferences, but are willing to compromise in order to collaboratively reach a common decision. Agents participating in the dialogue use internal reasoning to resolve conflicts emerging in their knowledge during communication and to reach a decision that requires the least compromises. Our approach has significant potential, as it may allow targeted knowledge exchange, partial disclosure of information and efficient or informed decision-making depending on the topic of the agents’ discussion.

IJCAI Conference 2009 Conference Paper

• Theodore Patkos
• Dimitris Plexousakis

We propose a new framework for reasoning about knowledge, action and time for domains that include actions with non-deterministic and contextdependent effects. The axiomatization is based on the Event Calculus and combines the expressiveness of possible worlds semantics with the efficiency of approaches that dispense the use of the accessibility relation. The framework is proved logically sound and, when restricted to deterministic domains, is also logically complete. To prove correctness of the approach, we construct a knowledge theory based on a branching version of the Event Calculus and study their correlation.