Ο Κωνσταντίνος Τζιούβας είναι Computational Social Scientist που γεφυρώνει την επιστήμη των υπολογιστών και τις κοινωνικές επιστήμες για να μελετήσει την κοινωνική πληροφορική, την ανάλυση κειμένων και την πολιτική συμπεριφορά. Κατασκευάζει ολοκληρωμένες διαδικασίες για την αυτόματη συλλογή, δομή και ανάλυση πολιτικών και κοινωνικών δεδομένων, μετατρέποντας μη δομημένες πηγές σε σύνολα δεδομένων ερευνητικού επιπέδου. Συν-σχεδιάζει και αξιολογεί διεπιστημονικά ερευνητικά εργαλεία, ιδίως τις εφαρμογές Voting Advice Applications (VAAs) και DataPoll, ένα σύστημα ανεξάρτητο από πλατφόρμες που επιτρέπει την ανάλυση μεγάλης κλίμακας σε όλους τους τομείς των κοινωνικών επιστημών. Μεθοδολογικά, ενσωματώνει τη μηχανική μάθηση, την ανάλυση δικτύων και την επεξεργασία φυσικής γλώσσας για να μοντελοποιήσει πολύπλοκες δομές πληροφοριών, να αποκαλύψει λανθάνοντα μοτίβα κειμένου και δικτύων και να αυτοματοποιήσει τη γλωσσική και επιχειρηματολογική ανάλυση. Πρόσφατα, έχει επικεντρωθεί στην κριτική αξιολόγηση μεγάλων γλωσσικών μοντέλων, στον χαρακτηρισμό και τον μετριασμό των προκαταλήψεων και στη χρήση τεχνικών απόσταξης πληροφοριών για τη δημιουργία μικρότερων, ερμηνεύσιμων μοντέλων για αυστηρή ανάλυση των προκαταλήψεων.

Ερευνητικά Eνδιαφέροντα: Computational Social Science; Social Computing; Text-As-Data; Political Behavior; Machine Learning; Natural Language Processing (NLP); LLM Audit & Bias; Model Interpretability.

ΕΡΕΥΝΗΤΙΚΑ ΕΡΓΑ & ΔΙΑΚΡΙΣΕΙΣ

Άρθρα σε Διεθνή Περιοδικά με Κριτές

• M. C. Voutsa, N. Tsapatsoulis, C. Djouvas, “Biased by Design? Evaluating Bias and Behavioral Diversity in LLM Annotation of Real-World and Synthetic Hotel Reviews.” AI 2025, vol. 6, no. 8, pp. 178, 2025. doi: 10.3390/ai6080178
• M. Germann, F. Mendez, J. Wheatley, C. Djouvas, R. Nezi, M. Wall, “Improving issue representation with candidate‐level voting advice applications.” European Journal of Political Research, vol. 64, no. 4, pp. 2132-2145, 2025, doi: 10.1111/1475-6765.70024
• A. Charalampous, C. Djouvas, C. Christodoulou, “DataPoll: A Tool Facilitating Big Data Research in Social Sciences,” in IEEE Transactions on Computational Social Systems, vol. 12, no. 2, pp. 511-524, 2025, doi: 10.1109/TCSS.2024.3506582
• S. Giannoulakis, N. Tsapatsoulis, C. Djouvas, “Evaluating the use of Instagram images color histograms and hashtags sets for automatic image annotation.” Frontiers in Big Data, vol. 6, 2023.
• P. Spyridou, C. Djouvas, D. Milioni, “Modeling and Validating a News Recommender Algorithm in a Mainstream Medium-Sized News Organization: An Experimental Approach.” Future Internet 2022, 14(10):284. https://doi.org/10.3390/fi14100284
• N. Tsapatsoulis, C. Djouvas, “Opinion mining from social media short texts: Does collective intelligence beat deep learning?” Journal of Frontiers in Robotics and AI, section Computational Intelligence, vol. 5, pp. 138, 2019.
• C. Djouvas, F. Mendez, N. Tsapatsoulis, “Mining online political opinion surveys for suspect entries: An interdisciplinary comparison.” Journal of Innovation in Digital Ecosystems, vol. 3, no. 2, pp. 172-182, 2016.
• N. Tsapatsoulis, M. Agathokleous, C. Djouvas, F. Mendez, “On the design of Social Voting Recommendation Applications.” International Journal on Artificial Intelligence Tools, vol. 24, no. 03, pp. 1550009, 2015.
• I. Katakis, N. Tsapatsoulis, F. Mendez, V. Triga, C. Djouvas, “Social voting advice applications-definitions, challenges, datasets and evaluation.” IEEE Transactions on Cybernetics, vol. 44, no. 7, pp. 1039-1052, 2013.
• L. Lambrinos, C. Djouvas, “Improving quality of experience in wireless voip through novel call scheduling.” Telecommunication Systems, vol. 52, no. 4, pp. 1905-1916, 2013.
• C. Djouvas, N. D. Griffeth, N. A. Lynch, “Testing self-similar networks.” Electronic Notes in Theoretical Computer Science, vol. 164, no. 4, pp. 67-82, 2006.

Κεφάλαια Βιβλίων

• C. Mendez, M. Gazzola, L. Clement-Wilz, V. Triga, F. Mendez, C. Djouvas, A. Charalampous, J. Bachtler, “The European Union’s approach to multilingualism in its own communication policy.” 2022, European Parliament. http://www.europarl.europa.eu/RegData/etudes/STUD/2022/699648/IPOL_STU(2022)699648_EN.pdf
• C. Mendez, M. Gazzola, L. Clement-Wilz, V. Triga, F. Mendez, C. Djouvas, A. Charamboulos, J. Bachtler, “Research for CULT Committee - The European Union's Approach to Multilingualism in its Own Communication Policy.” 2022 (Research for the CULT Committee).
• C. Chrysostomou, C. Djouvas, L. Lambrinos, “Fuzzy logic-based adaptive decision support in autonomous vehicular networks.” In Computational Intelligence for Decision Support in Cyber-Physical Systems, pp. 215-236, Springer, 2014.
• L. Lambrinos, C. Djouvas, “Using location information for sophisticated emergency call management.” In Wireless Mobile Communication and Healthcare, pp. 227-232, Springer, 2011.

Πρακτικά Συνεδρίων με Κριτές

• C. Djouvas, A. Charalampous, C. J. Christodoulou, N. Tsapatsoulis, “LLMs are not for everything: A Dataset and Comparative Study on Argument Strength Classification.” In Proceedings of the 28th Pan-Hellenic Conference on Progress in Computing and Informatics, pp. 437-443, Athens, Greece, 2025.
• C. Djouvas, C. Christodoulou, A. Charalampous, N. Tsapatsoulis, “Identifying Emerging Research Topics in Computer Science Using Overlapping Community Detection on Graph Neural Network Predicted Graphs.” IEEE Conference on Pervasive and Intelligent Computing (PICom), pp. 148-155, Boracay Island, Philippines, 2024. doi: 10.1109/PICom64201.2024.00028.
• A. Charalampous, C. Djouvas, N. Tsapatsoulis, E. Kouzaridi, “Emerging Research Topics Identification Using Temporal Graph Neural Networks.” In 2024 IFIP International Conference on Artificial Intelligence Applications and Innovations, pp. 192-205, Corfu, Greece, 2024. Cham: Springer Nature Switzerland.
• E. Kouzaridi, H. Partaourides, N. Tsapatsoulis, C. Djouvas, “Assessing the importance of key terms in UN SDGs through Citizens Labs.” In 2023 IEEE Conference on Pervasive and Intelligent Computing (PICom), pp. 0505-0511, Calabria, Italy, 2023.
• H. Partaourides, E. Kouzaridi, N. Tsapatsoulis, C. Djouvas, “On the Identification of Influential Topics in the Social Sciences Using Citation Analysis.” In 2023 IEEE Conference on Pervasive and Intelligent Computing (PICom), pp. 0845-0851, Calabria, Italy, 2023.
• C. Djouvas, C. Christodoulou, A. Charalampous, N. Ioannidis, “Identifying Euroscepticism Using a Text-As-Data Approach: An Experimental Study Employing Parliamentary Speeches.” 18th IEEE International Workshop on Semantic and Social Media Adaptation & Personalization (SMAP 2023), pp. 1-6, Limassol, Cyprus, 2023.
• C. Djouvas, N. Tsapatsoulis, A. Lanitis, “Implementing the EUt+ European Student Card via Open Source Services.” 18th International Workshop on Semantic and Social Media Adaptation & Personalization (SMAP 2023), pp 1-4, Limassol, Cyprus, 2023.
• H. Partaourides, E. Kouzaridi, N. Tsapatsoulis, C. Djouvas, “Thematic Modeling of UN Sustainable Development Goals: A Comparative Meta-based Approach.” AIAI 2023, 19th International Conference on Artificial Intelligence Applications and Innovations, pp. 557-568, León, Spain, 2023.
• N. Tsapatsoulis, H. Partaourides, C. Christodoulou, C. Djouvas, “Quo Vadis Computer Science? The topics of the influential papers during the period 2014-2021.” 2022 The 21st IEEE International Conference on Pervasive Intelligence and Computing (PICom 2023), pp. 1-8, Falerna, Italy, 2022. doi: 10.1109/DASC/PiCom/CBDCom/Cy55231.2022.9927789.
• C. Djouvas, A. Antoniou, N. Tsapatsoulis, “Improving Social Vote Recommendation in VAAs: The effects of political profile augmentation and classification method.” Proceedings of the 13th International Workshop on Semantic and Social Media Adaptation and Personalization (SMAP 2018), pp. 1-6, Zaragoza, Spain, September 2018.
• A. Founta, C. Djouvas, D. Chatzakou, I. Leontiadis, J. Blackburn, G. Stringhini, A. Vakali, M. Sirivianos, N. Kourtellis, “Large Scale Crowdsourcing and Characterization of Twitter Abusive Behavior.” International AAAI Conference on Web and Social Media (ICWSM), Stanford, California, USA, 2018.
• M. Agathokleous, N. Tsapatsoulis, C. Djouvas, “Estimating Party-user Similarity in Voting Advice Applications using Hidden Markov Models.” In the ACS Proceedings of the Joint Workshop on Interfaces and Human Decision Making for Recommender Systems co-located with ACM Conference on Recommender Systems (RecSys 2016), Boston, MA, USA, September 16, 2016.
• C. Djouvas, K. Gemenis, “SmartCoding: A web-based system for estimating parties policy positions.” WEBDATANET Conference, Salamanca, Spain, 2015.
• F. Mendez, K. Gemenis, C. Djouvas, “Pattern-based rogue identification.” WEBDATANET Conference, Salamanca, Spain, 2015.
• C. Djouvas, N. Tsapatsoulis, “A view behind the scenes: Data structures and software architecture of a VAA.” In the 9th IEEE International Workshop on Semantic and Social Media Adaptation and Personalization (SMAP), 2014, pp. 136-141, 2014.
• F. Mendez, K. Gemenis, C. Djouvas, “Methodological challenges in the analysis of voting advice application generated data.” In the 9th IEEE International Workshop on Semantic and Social Media Adaptation and Personalization (SMAP), pp. 142-148., 2014
• C. Djouvas, K. Gemenis, F. Mendez, “Weeding out the rogues: How to identify them and why it matters for VAA-generated datasets.” In European Consortium for Political Research General Conference, 2014.
• C. Chrysostomou, C. Djouvas, L. Lambrinos, “Contention window adaptation for broadcast beaconing in vehicular ad hoc networks.” In IEEE Wireless Communications and Mobile Computing Conference (IWCMC), 2014 International, pp. 1039-1044, 2014.
• L. Lambrinos, C. Djouvas, C. Chrysostomou, “Applying delay tolerant networking routing algorithms in maritime communications.” In World of Wireless, Mobile and Multimedia Networks (WoWMoM), 2013 14th IEEE International Symposium and Workshops on, pp. 1-6, IEEE, 2013.
• L. Lambrinos, P. Kolios, C. Djouvas, “Dimensioning VoIP capacity in maritime networks.” In Communications (ICC), 2013 IEEE International Conference on, pp. 2486-2490, IEEE, 2013.
• C. Chrysostomou, C. Djouvas, L. Lambrinos, “Dynamically adjusting the min-max contention window for providing quality of service in vehicular networks.” In Ad Hoc Networking Workshop (Med-Hoc-Net), 2012 The 11th Annual Mediterranean, pp. 16-23, IEEE, 2012.
• I. Katakis, N. Tsapatsoulis, V. Triga, C. Tziouvas, F. Mendez, “Clustering online poll data: Towards a voting assistance system.” In the IEEE Semantic and Social Media Adaptation and Personalization (SMAP), 2012 Seventh International Workshop on, pp. 54-59, IEEE, 2012.
• C. Chrysostomou, C. Djouvas, L. Lambrinos, “Applying adaptive qos-aware medium access control in priority-based vehicular ad hoc networks.” In IEEE Symposium on Computers and Communications (ISCC), 2011, pp. 741-747, 2011.
• L. Lambrinos, C. Djouvas, “Creating a maritime wireless mesh infrastructure for real-time applications.” In IEEE GLOBECOM Workshops, 2011, pp. 529-532, IEEE, 2011.
• C. Tziouvas, L. Lambrinos, C. Chrysostomou, “A delay tolerant platform for voice message delivery.” In the 14th International Symposium on Wireless Personal Multimedia Communications (WPMC), 2011, pp. 1-5, IEEE, 2011.
• C. Chrysostomou, L. Lambrinos, C. Djouvas, “The need for a system design methodology to address challenges in wireless access in vehicular ad hoc networks.” In International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2010, pp. 1226-1231, IEEE, 2010.
• L. Lambrinos, C. Djouvas, “Applying scheduling policies to improve QoS in wireless voice-over-ip.” In 28th IEEE International Performance Computing and Communications Conference (IPCCC), 2009, pp. 366-370, IEEE, 2009.
• N. Griffeth, Y. Cantor, C. Djouvas, “Testing a network by inferring representative state machines from network traces.” In Software Engineering Advances, International Conference on, pp. 31-31, IEEE, 2006.
• C. Djouvas, N. Griffeth, “Experimental method for testing networks.” Proceedings of the 2005 International Conference on Software Engineering Research and Practice, Las Vegas, Nevada, USA, 2005.
• G. Hadjipollas, C. Chrysostomou, C. Djouvas, A. Pitsillides, “Integrated Dynamic Congestion Control with Resource Management in a Differentiated Services Environment.”, 19th ACM Symposium on Applied Computing, Nicosia, Cyprus, 2004.

Παρουσιάσεις σε Συνέδρια (Χωρίς Πρακτικά)

• C. Christodoulou, N. Kovras, I. Ioannidis, C. Djouvas, “The contemporary aspect of the crime of enforced disappearances.” 15th Annual Conference of the European Political Science Association, Universidad Carlos III de Madrid, Spain, 26-28 June 2025.
• C. Christodoulou, N. Kovras, I. Ioannidis, C. Djouvas, “A practical guide on what not to write on the internet (if you are a dissident of an authoritarian regime).” 15th Annual Conference of the European Political Science Association, Universidad Carlos III de Madrid, Spain, 26-28 June 2025.
• C. Djouvas, M. Guinjoan, N. Ioannidis, F. Mendez, T. Rodon, “Strategic Choices: How Tailored Information Influences Election Dynamics.” 2024 ECPR General Conference, University College Dublin, 2024.
• C. Djouvas, V. Manavopoulos, F. Mendez, “As bad as humans: Can machine learning text analysis be used for framing analysis.” In the Proceedings of the 17th European Consortium of Political Research (ECPR 2023), Prague, Czech Republic, 2023.
• V. Papa, D. Milioni, C. Djouvas, “Can data activism strengthen the agency of ‘common’ users? An empirical study of oppositional affordances and use positions toward Facebook.” Data Power Dialogues, Bremen, Germany, 20-22 June 2022.
• C. Djouvas, V. Manavopoulos, F. Mendez, “Mapping Voters’ Engagement with Political Information Sites: The Case of Voting Advice Applications.” European Consortium for Political Research General Conference, 2021.
• V. Papa, D. Milioni, C. Djouvas, “Can data activism strengthen the agency of ‘common’ users? An empirical study of oppositional affordances and use positions toward Facebook.” Presentation at the Annual Conference of International Association of Media and Communication Research (IAMCR), “Communication, Technology and Human Dignity: Disputed Rights, Contested Truths.” University of Madrid, School of Communication, Madrid, Spain, 2019.
• D. Milioni, L. Kollyri, C. Djouvas, “Algorithmic profiling and news personalization.” Amsterdam Privacy Conference (APC 2018), Amsterdam, Netherlands, 2018.
• C. Djouvas, “Different Technologies, same Assumptions? Comparing the Response Behaviour (and Political Stance) of Mobile versus Desktop VAA users.” In the Proceedings of the 11th European Consortium of Political Research (ECPR 2017), Olso, Norway, 2017.

Τεχνικές Εκθέσεις

•  C. Djouvas, N. Griffeth, N. Lynch, "Using self-similarity for efficient network testing." Technical report, Lehman College, 2005.

Δημοσιευμένο Λογισμικό

•  C. Djouvas, F. Mendez. (2018, October 16). "VAA Balancing Tool (Version 0.1)." Zenodo. http://doi.org/10.5281/zenodo.1464098