Theodore Patkos

Foundation for Research and Technology - Hellas | forth · Information Systems Laboratory (ISL)

Domain-specific knowledge can significantly contribute to addressing a wide variety of vision tasks. However, the generation of such knowledge entails considerable human labor and time costs. This study investigates the potential of Large Language Models (LLMs) in generating and providing domain-specific information through semantic embeddings. To...

The wine industry has evolved thanks to the introduction of digital technologies in every aspect of the wine production chain and the emerging need of the food industry for qualitative, sustainable, and safe products. As a result, the incorporation of digital services that facilitate access to related data of wine products is crucial for wine enter...

The wine industry has evolved thanks to the introduction of digital technologies in every aspect of the wine production chain and the emerging need of the food industry for qualitative, sustainable, and safe products. As a result, the incorporation of digital services that facilitate access to related data of wine products is crucial for wine enter...

The exchange of comments, opinions, and arguments in blogs, forums, social media, wikis, and review websites has transformed the Web into a modern agora, a virtual place where all types of debates take place. This wealth of information remains mostly unexploited: due to its textual form, such information is difficult to automatically process and an...

Reasoning about actions, change, and causality constitutes an important field of research in artificial intelligence. Several formal action languages have been proposed, addressing the need to qualify change and facilitate (commonsense) reasoning in dynamic settings. The Event Calculus (EC), in particular, permits the representation of causal and n...

The authors present a knowledge retrieval framework for the household domain enhanced with external knowledge sources that can argue over the information that it returns and learn new knowledge through an argumentation dialogue. The framework provides access to commonsense knowledge about household environments and performs semantic matching betwee...

The detection of object states in images (State Detection - SD) is a problem of both theoretical and practical importance and it is tightly interwoven with other important computer vision problems, such as action recognition and affordance detection. It is also highly relevant to any entity that needs to reason and act in dynamic domains, such as r...

This paper presents a novel abstract argumentation framework, called Multi-Attack Argumentation Framework (MAAF), which supports different types of attacks. The introduction of types gives rise to a new family of non-standard semantics which can support applications that classical approaches cannot, while also allowing classical semantics as a spec...

Infusing autonomous artificial systems with knowledge about the physical world they inhabit is of utmost importance and a long-lasting goal in Artificial Intelligence (AI) research. Training systems with relevant data is a common approach; yet, it is not always feasible to find the data needed, especially since a big portion of this knowledge is co...

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 sem...

Digital applications typically describe their privacy policy in lengthy and vague documents (called PrPs), but these are rarely read by users, who remain unaware of privacy risks associated with the use of these digital applications. Thus, users need to become more aware of digital applications’ policies and, thus, more confident about their choice...

Automatic deception detection is a crucial task that has many applications both in direct physical and in computer-mediated human communication. Our focus is on automatic deception detection in text across cultures. In this context, we view culture through the prism of the individualism/collectivism dimension, and we approximate culture by using co...

CAP-A is offering socio-technical tools to promote collective awareness and informed consent, whereby data collection and use by digital products are driven by the expectations and needs of the consumers themselves.

Deception detection is a task with many applications both in direct physical and in computer-mediated communication. Our focus is on automatic deception detection in text across cultures. We view culture through the prism of the individualism/collectivism dimension and we approximate culture by using country as a proxy. Having as a starting point r...

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 t...

Recent extensions of the Event Calculus resulted in powerful formalisms, able to reason about a multitude of commonsense phenomena in causal domains, involving epistemic notions, functional fluents and probabilistic aspects, among others. Less attention has been paid to the problem of automatically revising (correcting) a Knowledge Base when an obs...

Consumers are largely unaware regarding the use being made to the data that they generate through smart devices, or their GDPR-compliance, since such information is typically hidden behind vague privacy policy documents, which are often lengthy, difficult to read (containing legal terms and definitions) and frequently changing. This paper describes...

The utilisation of personal data by mobile apps is often hidden behind vague Privacy Policy documents, which are typically lengthy, difficult to read (containing legal terms and definitions) and frequently changing. This paper discusses a suite of tools developed in the context of the CAP-A project, aiming to harness the collective power of users t...

Rewarding people is common in several contexts, such as human resource management and crowdsourcing applications. However, designing a reward strategy is not straightforward, as it requires considering different parameters. These parameters include, for example, management of rewarding tasks and identifying critical features, such as the type of re...

In the field of domestic cognitive robotics, it is important to have a rich representation of knowledge about how household objects are related to each other and with respect to human actions. In this paper, we present a domain dependent knowledge retrieval framework for household environments which was constructed by extracting knowledge from the...

The field of Computational Argumentation is well-tailored to approach commonsense reasoning, due to its ability to model contradictory information. In this paper, we present preliminary work on how an argumentation framework can explicitly model commonsense knowledge, both at a logically structured and at an abstract level. We discuss the correlati...

Rewarding people is common in several contexts, such as human resource management and crowdsourcing applications. However, designing a reward strategy is not straightforward, as it requires considering different parameters. These parameters include, for example, management of rewarding tasks and identifying critical features, such as the type of re...

Object perception is a fundamental sub-field of Computer Vision, covering a multitude of individual areas and having contributed high-impact results. While Machine Learning has been traditionally applied to address related problems, recent works also seek ways to integrate knowledge engineering in order to expand the level of intelligence of the vi...

ECAVI (Event Calculus Analysis and VIsualisation), is a domain independent visual modelling tool for designing dynamic domains in the Event Calculus. ECAVI is mainly addressed to inexperienced modellers, aiming to acquaint them with the features of the Event Calculus (and consequently commonsense reasoning) and to guide them during the process of d...

The field of logic-based Knowledge Representation and Reasoning has produced powerful formalisms for modeling commonsense knowledge in Artificial Intelligence. In this paper, we present EduBAI, an educational platform that helps users familiarize themselves with the main tenets of commonsense reasoning in dynamic, causal domains by means of an inte...

In an increasingly instrumented and inter-connected digital world, citizens generate vast amounts of data, much of it being valuable and a significant part of it being personal. However, controlling who can collect it, limiting what they can do with it, and determining how best to protect it, remain deeply undecided issues. This paper proposes CAPr...

The goal of our research has been to integrate existing information systems and to design and implement a prototype of a digital personal travel assistant for travelers, called Travel Companion. Travel Companion assists a traveler through various guidance functions, and offers personalized reminders and recommendations, which are based on the trave...

The CAPrice initiative brings to the fore the creativity of the community towards privacy via specific co-creation tools (structured debates, annotation tools, reward mechanisms and others). Our objective is to improve citizen awareness on privacy issues, and leverage this awareness to motivate the market to adopt more privacy-friendly practices.

User 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 shopping habits, businesses and the overall market. Despite that, systems have so far limited practical success in helping consumers and businesses analysing, managing and understanding Social Web content. I...

A vast amount of opinions are surfacing on the Web but the lack of mechanisms for managing them leads to confusing and often chaotic dialogues. This creates the need for further semantic infrastructure and analysis of the views expressed in large-volume discussions. In this paper, we describe a web platform for modeling and analyzing argumentative...

Publication management systems can be instrumental in disseminating research results across academia and industry, by providing facilities for uploading, editing and searching for publications. Usually, these systems can be used by individuals to assist them in their research or by organizations to help them classify and promote their publication i...

Background Parallel data manipulation using R has previously been addressed by members of the R community, however most of these studies produce ad hoc solutions that are not readily available to the average R user. Our targeted users, ranging from the expert ecologist/microbiologists to computational biologists, often experience difficulties in fi...

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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 fiel...

Purpose – Marine species data are scattered across a series of heterogeneous repositories and information systems. There is no repository that can claim to have all marine species data. Moreover, information on marine species are made available through different formats and protocols. The purpose of this paper is to provide models and methods that...

Action languages have emerged as an important field of Knowledge Representation for reasoning about change and causality in dynamic domains. This article presents Cerbere, a production system designed to perform online causal, temporal and epistemic reasoning based on the Event Calculus. The framework implements the declarative semantics of the und...

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 applicatio...

The LifewatchGreece project builds the national hub of the European Research Infrastructure LifeWatch (ESFRI) on biodiversity data and data observatories. A suite of electronic services (e-Services) and virtual labs (vLabs) are under development to facilitate both the data providers and the users. The R-vLab is a powerful application hosted in the...

In this chapter we discuss the necessity to move beyond built-in monotonic semantic web based reasoning-architectures for endowing ubiquitous robots with cognitive capabilities, which are strongly required in ambient assistive living, towards new architectures that combine different reasoning mechanisms to achieve better context awareness and adapt...

We characterize different types of conflicts that often occur in complex distributed multi-agent scenarios, such as in Ambient Intelligence (AmI) environments, and we argue that these conflicts should be resolved in a suitable order and using the most appropriate conflict resolution strategies for each individual conflict type. Our analysis shows t...

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 communica...

Reasoning about Action and Change (RAC) and Answer Set Programming (ASP) are two well-known fields in AI for logic-based reasoning. Each paradigm bears unique features and a possible integration can lead to more effective ways to address hard AI problems. In this paper, we report on implementations that embed RAC formalisms and concepts in ASP and...

We present a generalisation of the Event Calculus, specified in classical logic and implemented in ASP, that facilitates reasoning about non-binary-valued fluents in domains with non-deterministic, triggered, concurrent, and possibly conflicting actions. We show via a case study how this framework may be used as a basis for a "possible-worlds" styl...

Purpose – Marine species data are scattered across a series of heterogeneous repositories and information systems. There is no repository that can claim to have all marine species data. Moreover, information on marine species are made available through different formats and protocols. The purpose of this paper is to provide models and methods that...

This paper presents a rule-based architecture that enables causal and temporal reasoning of events and supports their relevance assessment given the user's situation, in order to provide contextualized services for citizens inhabiting a smart city. Our approach for context reasoning and assessment is illustrated by emergency scenarios.

Action theories are an important field of knowledge representation for reasoning about change and causality in dynamic domains. In practical implementations agents often have incomplete knowledge about the environment and need to acquire information at runtime through sensing, the basic ontology of action theories needs to be extended with epistemi...

Ambient Intelligence is an emerging discipline that requires the integration of expertise from a multitude of scientific fields. The role of Artificial Intelligence is crucial not only for bringing intelligence to everyday environments, but also for providing the means for the different disciplines to collaborate. In this paper we highlight the imp...

Ambient Intelligence is an emerging discipline that requires the integration of expertise from a multitude of scientific fields. The role of Artificial Intelligence is crucial not only for bringing intelligence to everyday environments, but also for providing the means for the different disciplines to collaborate. In this paper we describe the desi...

Knowledge and causality play an essential role in the attempt to achieve commonsense reasoning in cognitive robotics. As agents usually operate in dynamic and uncertain environments, they need to acquire information through sensing inertial aspects, such as the state of a door, and continuously changing aspects, such as the location of a moving obj...

Location-based services have evolved significantly during the last few years and are reaching a maturity phase, relying primarily on the experience gained and the utilization of recent technologies, such as ontology-based modeling and rule-based reasoning. Ontologies are used to classify the terms used in a particular application, characterize poss...

We propose a new framework for reasoning about knowledge, action and time for domains that in- clude actions with non-deterministic and context- dependent effects. The axiomatization is based on the Event Calculus and combines the expressive- ness of possible worlds semantics with the effi- ciency of approaches that dispense the use of the accessib...

The ubiquitous intelligence vision requires the development of systems that integrate sensing, computing and networking with advanced techniques for data and knowledge representation and management. Taking advantage of these opportunities, this paper presents a context-aware navigation guide, strongly connected to the semantics of user profile. Our...

Location‐based ubiquitous services have evolved significantly during the last years and are reaching a maturity phase, relying primarily on the experience gained and the utilisation of recent technologies. This paper presents a context‐aware platform for mobile devices in dynamic environments, which uses Semantic Web technologies to model context i...

Location-based services have evolved significantly during the last few years and are reaching a maturity phase, relying primarily on the experience gained and the utilization of recent technologies. Taking advantage of these opportunities, this paper presents a context-aware navigation guide, strongly connected to the semantics behind user profile....

To regulate and coordinate the behavior of agents within real-world environments, the participating entities must be able to reason not only about the state of the environment itself, but also about their own knowledge concerning that state, based on information acquired through sensing actions. Considering the dynamic nature of most realistic doma...

The Ambient Intelligence paradigm has evolved significantly during the last few years and aims at developing context-aware and adaptive systems that enable people to use personalized services. Context-awareness, semantics enriched services and adaptivity are among the features that characterize Ambient Intelligence systems. In this paper, we descri...

A key issue in the study of Ambient Intelligence is reasoning about context. The aim of context reasoning is to deduce new knowledge, based on the available context data. The endmost goal is to make the ambient services more ”intelligent”; closer to the specific needs of their users. The main challenges of this effort derive from the imperfect cont...

Research in many flelds of AI, such as distributed plan- ning and reasoning, agent teamwork and coalition formation, cooper- ative problem solving and action theory has advanced signiflcantly over the last years, both from a theoretical and a practical perspective. In the light of the development towards ambient, pervasive and ubiqui- tous computin...

Location-based ubiquitous services have evolved significantly during the last years and are reaching a maturity phase, relying primarily on the experience gained and the utilization of recent technologies. This paper proposes a context-aware platform for mobile devices in dynamic environments, which uses Semantic Web technologies to model context i...

Achieving interoperability and automation in job execution is of utmost importance for next generation e-Commerce applications. This paper proposes a design that integrates three prominent technologies: intelligent software agents, peer-to-peer networking and the Semantic Web. SeMPHoNIA is an architecture for an agent-based marketplace, utilizing k...

Recent years have seen an enormous increase in the amount of information and services accessible online, causing the task of discovering and trading resources to become highly complex. Still, human users are actively involved in all phases of the e-Commerce interaction process. Moreover, the current economic trading sphere is structured on top of a...

Location-based services have evolved significantly dur- ing the last years and are reaching a maturity phase, relying primar- ily on the experience gained and the utilization of recent technolo- gies. This paper identifies main fields of research and key challenges for the proliferation of such services and proposes a framework for building locatio...