Work Experience

Education

  • M.Eng. 2012

    M.Eng. in Electrical and Computer Engineering

    Faculty of Engineering, Aristotle University of Thessaloniki

Seminars and Training

  • 2016
    Angular.js Online Course
  • 2014
    Python Online Course
  • 2012
    Europe3D Portugal
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    Education-purposed event about local economy, industry, politics and culture. Held by ESTIEM in Porto and Coimbra.
  • 2011
    Europe3D Spain
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    Education-purposed event about local economy, industry, politics and culture. Held by ESTIEM in Seville.
  • 2010
    Seminar on Photovoltaic Systems
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    Covering photovoltaic installation methods.
  • 2009
    Seminar on MatLab
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    Organized by the ITC division of Aristotle University of Thessaloniki.

Research Partners

Georgios Meditskos

Postdoctoral Research Associate

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Ioannis Kompatsiaris

Researcher A'

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Efstratios Kontopoulos

Postdoctoral Research Associate

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Marina Riga

Research Associate

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Multimedia Knowledge and Social Media Analytics Laboratory (MKLab)

 

MKLab has extensive experience and expertise in semantic multimedia analysis, indexing and retrieval, social media and big data analytics, knowledge structures, reasoning and personalization for multimedia applications, eHealth and environmental applications.

Research Projects

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    PERICLES

    Promoting and Enhancing Reuse of Information throughout the Content Lifecycle taking account of Evolving Semantics

    PERICLES is a four-year project that aims to address the challenge of ensuring that digital content remains accessible in an environment that is subject to continual change. This can encompass not only technological change, but also changes in semantics, academic or professional practice, or society itself, which can affect the attitudes and interests of the various stakeholders that interact with the content. PERICLES will take a ‘preservation by design’ approach that involves modelling, capturing and maintaining detailed and complex information about digital content, the environment in which it exists, and the processes and policies to which it is subject.

    PERICLES is an Integrated Project funded by the European Union under its Seventh Framework Programme (ICT Call 9).

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    Dem@Care

    Dementia Ambient Care: Multi-Sensing Monitoring for Intelligent Remote Management and Decision Support

    Dem@Care aspires to contribute to the timely diagnosis, assessment, maintenance and promotion of self-independence of people with dementia, by deepening the understanding of how the disease affects their everyday life and behaviour. It implements a multi-parametric closed-loop remote management solution that affords adaptive feedback to the person with dementia, while at the same time including clinicians into the remote follow-up, enabling them to maintain a comprehensive view of the health status and progress of the affected person.

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Dependency modelling for inconsistency management in Digital Preservation – The PERICLES approach

Nikolaos Lagos, Marina Riga, Panagiotis Mitzias, Jean-Yves Vion-Dury, Efstratios Kontopoulos, Simon Waddington, Pip Laurenson, Georgios Meditskos, Ioannis Kompatsiaris
Journal Paper Information Systems Frontiers

Abstract

The rise of the Semantic Web has provided cultural heritage researchers and practitioners with several tools for providing semantically rich representations and interoperability of cultural heritage collections. Although indeed offering a lot of advantages, these tools, which come mostly in the form of ontologies and related vocabularies, do not provide a conceptual model for capturing contextual and environmental dependencies, contributing to long-term digital preservation. This paper presents one of the key outcomes of the PERICLES FP7 project, the Linked Resource Model, for modelling dependencies as a set of evolving linked resources. The adoption of the proposed model and the consistency of its representation are evaluated via a specific instantiation involving the domain of digital video art.

SemaDrift: A Protégé Plugin for Measuring Semantic Drift in Ontologies

Thanos G. Stavropoulos, Stelios Andreadis, Efstratios Kontopoulos, Marina Riga, Panagiotis Mitzias, Ioannis Kompatsiaris

Conference Paper Detection, Representation and Management of Concept Drift in Linked Open Data (Drift-a-LOD) co-located with the 20th International Conference on Knowledge Engineering and Knowledge Management (EKAW), At Bologna, Italy

Abstract

Semantic drift is an active research field, which aims to identify and measure changes in ontologies across time and versions. Yet, only few practical methods have emerged that are directly applicable to Semantic Web constructs, while the lack of relevant applications and tools is even greater. This paper presents a novel software tool developed in the context of the PERICLES FP7 project that integrates currently investigated methods, such as text and structural similarity, into the popular ontology authoring platform, Protégé. The graphical user interface provides knowledge engineers and domain experts with access to methods and results without prior programming knowledge. Its applicability and usefulness are validated through two proof-of-concept scenarios in the domains of Web Services and Digital Preservation; especially the latter is a field where such long-term insights are crucial.

User-driven Ontology Population from Linked Data Sources

Panagiotis Mitzias, Marina Riga, Efstratios Kontopoulos, Thanos G. Stavropoulos, Stelios Andreadis, Georgios Meditskos, Ioannis Kompatsiaris

Conference Paper 7th Int. Conf. on Knowledge Engineering and Semantic Web (KESW'16), At Prague, Czech Republic, Volume: 649

Abstract

In order for ontology-based applications to be deployed in real-life scenarios, significant volumes of data are required to populate the underlying models. Populating ontologies manually is a time-consuming and error-prone task and, thus, research has shifted its attention to automatic ontology population methodologies. However, the majority of the proposed approaches and tools focus on analysing natural language text and often neglect other more appropriate sources of information, such as the already structured and semantically rich sets of Linked Data. The paper presents PROPheT, a novel ontology population tool for retrieving instances from Linked Data sources and subsequently inserting them into an OWL ontology. The tool, to the best of our knowledge, offers entirely novel ontology population functionality to a great extent and has already been positively received according to user evaluation.

A Framework for Measuring Semantic Drift in Ontologies

Thanos G. Stavropoulos, Stelios Andreadis, Marina Riga, Efstratios Kontopoulos, Panagiotis Mitzias, Ioannis Kompatsiaris

Conference Paper 1st Int. Workshop on Semantic Change & Evolving Semantics (SuCCESS'16), co-located with the 12th European Conference on Semantics Systems (SEMANTiCS'16), At Leipzig, Germany

Abstract

Semantic drift is an active field of research, aiming to identify and measure changes in ontologies across time and versions, closely related to ontology evolution. However, practical and widely adopted methods that are directly applicable to Semantic Web constructs have yet to emerge. Building upon and extending existing work, this paper presents a framework for measuring semantic drift in ontologies across time or multiple versions, using text and structural similarity methods to provide valuable insights. Its applicability and usefulness are validated through a proof-of-concept scenario in Digital Preservation, where long-term insights about change are crucial, to track drift across a decade's worth of real-world digital media data.

Ontology-based Representation of Context of Use in Digital Preservation

Efstratios Kontopoulos, Marina Riga, Panagiotis Mitzias, Stelios Andreadis, Thanos G. Stavropoulos, Nikolaos Lagos, Jean-Yves Vion-Dury, Georgios Med-itskos, Patricia Falcão, Pip Laurenson, Ioannis Kompatsiaris

Conference Paper 1st Workshop on Humanities in the Semantic Web - WHiSe, co-located with the 13th Extended Semantic Web Conference (ESWC 2016), At Heraklion, Crete, Greece, Volume: CEUR Workshop Proceedings, Vol-1608, pp. 65-72

Abstract

The fields of Digital Humanities and Digital Preservation are not yet enjoying the full potential of the Semantic Web and relevant technologies, largely due to the highly contextualized nature of their source materials. This paper addresses the issue of representing context and use-context (i.e. context of use) of digital content, by proposing an ontology-based representation approach , which is based on the LRM, an upper-level ontology for describing dependencies between digital resources.

PERICLES Deliverable 4.5: Context-aware Content Interpretation

Efstratios Kontopoulos, Sándor Darányi, Peter Wittek, Konstantinos Konstantinidis, Marina Riga, Panagiotis Mitzias, Thanos G. Stavropoulos, Stelios Andreadis, Anastasios Maronidis, Anastasios Karakostas, Stavros Tachos, Vagia Kaltsa, M. Tsagiopoulou, Kostas Avgerinakis

Technical Report

Abstract

The current deliverable summarizes the work conducted within task T4.5 of WP4, presenting our proposed approaches for contextualized content interpretation, aimed at gaining insightful contextualized views on content semantics. This is achieved through the adoption of appropriate context-aware semantic models developed within the project, and via enriching the semantic descriptions with background knowledge, deriving thus higher level contextualised content interpretations that are closer to human perception and appraisal needs.

PERICLES Deliverable 4.4: Modelling Contextualised Semantics

Efstratios Kontopoulos, Marina Riga, Panagiotis Mitzias, Stelios Andreadis, Thanos G. Stavropoulos, Konstantinos Konstantinidis, Anastasios Maronidis, Anastasios Karakostas, Stavros Tachos, Vagia Kaltsa, M. Tsagiopoulou, Sándor Darányi, Peter Wittek, Alastair Gill, Emma Tonkin, Simon Waddington, Christine Sauter, Fabio Corubolo

Technical Report

Abstract

This document summarises the work conducted within task T4.4 of WP4, presenting our proposed models for semantically representing digital content and its respective context – the latter refers to any information coming from the environment of the digital object (DO) that offers better insight into the object’s status, its interrelationships with other content items and information about the object’s context of use.

PERICLES Deliverable 4.3: Content Semantics and Use Context Analysis Techniques

Anastasios Maronidis, Elisavet Chatzilari, Efstratios Kontopoulos, S. Nikopoulos, Marina Riga, Panagiotis Mitzias, Sándor Darányi, Peter Wittek, Alastair Gill, Emma Tonkin, David De Weerdt, Fabio Corubolo, Simon Waddington, Christin Sauter

Technical Report

Abstract

This document summarizes the work conducted within task T4.3 of WP4, focusing on the extraction and the subsequent analysis of semantic information from digital content, which is imperative for its preservability. More specifically, the deliverable defines content semantic information from a visual and textual perspective, explains how this information can be exploited in long-term digital preservation and proposes novel approaches for extracting this information in a scalable manner.

PERICLES – Digital Preservation through Management of Change in Evolving Ecosystems

Simon Waddington, Mark Hedges, Marina Riga, Panagiotis Mitzias, Efstratios Kontopoulos, Ioannis Kompatsiaris, Jean-YvesVion-Dury, Nikolaos Lagos, Sándor Darányi, Fabio Corubolo, Christian Muller, John McNeill

Book Chapter The Success of European Projects using New Information and Communication Technologies, Chapter: 4, Publisher: SCITEPRESS Digital Library, Editors: Sofiane Hamrioui, pp.59-82

Abstract

Management of change is essential to ensure the long-term reusabil-ity of digital assets. Change can be brought about in many ways, including through technological, user community and policy factors. Motivated by case studies in space science and time-based media, we consider the impact of change on complex digital objects comprising multiple interdependent entities, such as files, software and documentation. Our approach is based on modelling of digital ecosystems, in which abstract representations are used to assess risks to sustainability and support tasks such as appraisal. The paper is based on work of the EU FP7 PERICLES project on digital preservation, and presents some general concepts as well as a description of selected research areas under investigation by the project.

An Ontology Design Pattern for Digital Video

Panagiotis Mitzias, Marina Riga, Simon Waddington, Efstratios Kontopoulos, Georgios Meditskos, PipLaurenson, Ioannis Kompatsiaris

Conference Paper 6th Workshop on Ontology and Semantic Web Patterns (WOP 2015) co-located with the 14th International Semantic Web Conference (ISWC 2015), At Bethlehem, Pensylvania, USA, Volume: Vol-1461

Abstract

In this paper we introduce an ODP for representing digital video resources. The aim is to model digital video files, their components and other associated entities, such as codecs and containers. The proposed design pattern facilitates the creation of relevant domain ontologies that will be deployed in the fields of media archiving and digital preservation of videos and video art-works. This ODP has been developed within the PERICLES FP7 project.

Designing for Inconsistency – The Dependency-based PERICLES Approach

Jean-Yves Vion-Dury, Nikolaos Lagos, Efstratios Kontopoulos, Marina Riga, Panagiotis Mitzias, Georgios Meditskos, Simon Waddington, Pip Laurenson, Ioannis Kompatsiaris

Conference Paper First International Workshop on Semantic Web for Cultural Heritage In Conjunction with 19th East-European Conference on Advances in Databases and Information Systems (ADBIS 2015), At Futuroscope, France, Volume: Volume 359 of the series Communications in Computer and Information Science, pp. 458-467.

Abstract

The rise of the Semantic Web has provided cultural heritage researchers and practitioners with several tools for ensuring semantic-rich representations and interoperability of cultural heritage collections. Although indeed offering a lot of advantages, these tools, which come mostly in the form of ontologies and related vocabularies, do not provide a conceptual model for capturing contextual and environmental dependencies contributing to long-term digital preservation. This pa-per presents one of the key outcomes of the PERICLES FP7 project, the Linked Resource Model, for modelling dependencies as a set of evolving linked re-sources. The proposed model is evaluated via a domain-specific representation involving digital video art.

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    SentiGeek

    Natural language processing

    SentiGeek analyzes customer reviews & comments on automated cloud or on-premise platform with innovative & advanced algorithms.

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    Genius Controls

    Software development for electronic systems

    Genius Controls perform design and implementation of custom electronic systems, industrial and home automations.

Skills and Experience

  • Python 90%
  • PyQt 100%
  • Protégé 90%
  • SPARQL 90%
  • OWL/RDF 80%
  • SQL/SQLite 70%
  • MS Visual Studio 60%
  • HTML/CSS 50%
  • PHP 40%




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