Publications

Selected Publications and Reports

  • “Vasileios Perifanis; George Drosatos; Giorgos Stamatelatos; Pavlos S. Efraimidis, FedPOIRec: Privacy-Preserving Federated POI Recommendation with Social Influence”, accepted in Information Sciences, Elsevier, 2022.
  • V. Perifanis, G. Stamatelatos, G. Drosatos, I. Michailidi and P.S. Efraimidis, Predicting Early Dropouts of an Active and Healthy Ageing App, IFMBE Challenge 2022 submission accepted for IUPESM World Conference on Medical Physics and Biomedical Engineering (IUPESM_WC2022).
  • Vasileios Perifanis and Pavlos S. Efraimidis, Federated Neural Collaborative Filtering, Knowledge-Based Systems 242 (2022): 108441, Elsevier.
  • P. Kostamis, A. Sendros, and P. S. Efraimidis, Exploring Ethereum’s Data Stores: A Cost and Performance Comparison, BRAINS 2021, DOI: https://doi.org/10.1109/BRAINS52497.2021.9569804
  • @article{stamatelatos2021poigraph, author={Stamatelatos, Giorgos and Drosatos, George and Gyftopoulos, Sotirios and Briola, Helen and Efraimidis, Pavlos S.}, title={Point-of-interest lists and their potential in recommendation systems}, journal={Information Technology {\&} Tourism, Springer}, year={2021}, month={Feb}, day={01}, issn={1943-4294}, doi={10.1007/s40558-021-00195-5}, url={https://doi.org/10.1007/s40558-021-00195-5} }
  • V. Katos and P. Efraimidis, Privacy in data-driven circular economy, accepted in Encyclopedia of Cryptography, Security and Privacy, Springer.
  • A. Tasidou, A. and P. Efraimidis, Economics of Personal Data, accepted in Encyclopedia of Cryptography, Security and Privacy, Springer.
  • @article{gyftopoulos2020twitter, title={A Twitter-based approach of news media impartiality in multipartite political scenes}, author={Gyftopoulos, Sotirios and Drosatos, George and Stamatelatos, Giorgos and Efraimidis, Pavlos S}, journal={Social Network Analysis and Mining, Springer}, volume={10}, number={36}, pages={36}, year={2020}, doi = {10.1007/s13278-020-00642-x}, url = {https://link.springer.com/article/10.1007%2Fs13278-020-00642-x}, publisher={Springer} }
  • @article{STAMATELATOS2020102172, title = {Revealing the political affinity of online entities through their Twitter followers}, journal = {Information Processing \& Management, Springer}, volume = {57}, number = {2}, pages = {102172}, year = {2020}, issn = {0306-4573}, doi = {10.1016/j.ipm.2019.102172}, url = {http://www.sciencedirect.com/science/article/pii/S0306457319305023}, author = {Giorgos Stamatelatos and Sotirios Gyftopoulos and George Drosatos and Pavlos S. Efraimidis}, keywords = {Social network analysis, Twitter followers, News media, Political affinity} }
  • Dimitriadis, A., Drosatos, G., Efraimidis, P. S. (2019, November). How much does a zero-permission Android app know about us?. In Proceedings of the Third Central European Cybersecurity Conference (pp. 1-5).
  • @inproceedings{Briola:2018, author = {Briola, Helen and Drosatos, George and Stamatelatos, Giorgos and Gyftopoulos, Sotirios and Efraimidis, Pavlos S.}, title = {Privacy Leakages about Political Beliefs through Analysis of Twitter Followers}, booktitle = {Proceedings of the 22nd Pan-Hellenic Conference on Informatics (PCI 2018)}, year = {2018}, isbn = {978-1-4503-6610-6/18/11}, location = {Athens, Greece}, pages = {1--6}, numpages = {6}, doi = {10.1145/3291533.3291557}, publisher = {ACM}, address = {New York, NY, USA}, keywords = {Social network analysis, Privacy leakages, Political beliefs, Twitter followers} }
  • @inproceedings{stamatelatos2018deriving, title={Deriving the Political Affinity of Twitter Users from Their Followers}, author={Stamatelatos, Giorgos and Gyftopoulos, Sotirios and Drosatos, George and Efraimidis, Pavlos S}, booktitle={Proceedings of the 11th IEEE International Conference on Social Computing}, doi = {10.1109/BDCloud.2018.00173}, year={2018}, organization={IEEE} }
  • Sotirios Gyftopoulos; Pavlos Efraimidis; Panagiotis Katsaros, Formal Analysis of DeGroot Influence Problems using Probabilistic Model Checking, Journal of Simulation Modelling Practice and Theory (SIMPAT), 89 (2018): 144-159, Elsevier.
  • A.-S. Kleinaki, P. Mytis-Gkometh, G. Drosatos, P. S. Efraimidis and E. Kaldoudi, A Blockchain-based Notarization Service for Biomedical Knowledge Retrieval, Computational and Structural Biotechnology Journal, 16 (2018): 288-297, Elsevier.
  • George Drosatos, Kyriakos Bakirlis, Pavlos Efraimidis and Eleni Kaldoudi, Communicating Personalized Risk Factors for Lifestyle Coaching, HealthInf 2018, pp. 571-578.
  • P. Mytis-Gkometh, G. Drosatos, P. S. Efraimidis and E. Kaldoudi, Notarization of Knowledge Retrieval from Biomedical Repositories using Blockchain Technology, ICBHI 2017, November 18-21, 2017, Thessaloniki, pp. 69-73, Springer.
  • Achilleas Platanitis, Sotirios Gyftopoulos, Pavlos S. Efraimidis, Stochastic Games : Studying a Card Game, accepted in Student’s Conference of Electrical and Computer Engineering (ECESCON) 2017.
  • Drosatos, George, Aimilia Tasidou, and Pavlos S. Efraimidis. “Privacy-Enhanced Television Audience Measurements.” ACM Transactions on Internet Technology (TOIT) 17, 1, Article 10 (February 2017), 29 pages. DOI: https://doi.org/10.1145/3009969.
  • Remous‐Aris Koutsiamanis and Pavlos S. Efraimidis. “Implementing PacketEconomy: Distributed money‐based QoS in OMNET++.” International Journal of Communication Systems 30.11 (2017).
  • @inproceedings{gyftopoulos2016solving, title={Solving Influence Problems on the DeGroot Model with a Probabilistic Model Checking Tool}, author={Gyftopoulos, Sotirios and Efraimidis, Pavlos S and Katsaros, Panagiotis}, booktitle={Proceedings of the 20th Pan-Hellenic Conference on Informatics}, pages={31}, year={2016}, organization={ACM} }
  • Pavlos S. Efraimidis, George Drosatos, Avi Arampatzis. G. Stamatelatos, Ioannis N. Athanasiadis. A Privacy-by-Design Contextual Suggestion System for Tourism. Journal of Sensor and Actuator Networks, 5(2), 10, special issue on “Techno-Human Collective Systems for Smart Cities Innovation”, 2016.
    • A preliminary version of this work appeared as @inproceedings{drosatos2015pythia, title={Pythia: A Privacy-enhanced Personalized Contextual Suggestion System for Tourism}, author={George Drosatos and Pavlos S. Efraimidis and Avi Arampatzis and Giorgos Stamatelatos and Ioannis N, Athanasiadis}, booktitle={Computer Software and Applications Conference (COMPSAC), 2015 IEEE 39th Annual}, volume={2}, pages={822--827}, year={2015}, organization={IEEE} }
  • Antonios Dimitriadis, Pavlos S. Efraimidis and Vasilios Katos, Malevolent App Pairs: An Android Permission Overpassing Scheme, accepted in 1st International Workshop for Malicious Software and Hardware in Internet of Things (MAL-IoT 2016), in proceedings of the ACM International Conference on Computing Frontiers (pp. 431-436).
  • George Drosatos, Pavlos S. Efraimidis, Garrath Williams and Eleni Kaldoudi,”Towards Privacy by Design in Personal e-Health Systems.” Proc. of the 9th International Conference on Health Informatics (HealthInf 2016), part of BIOSTEC, pp. 472-477, 2016.
  • Aimilia Tasidou, Pavlos S. Efraimidis, Yannis Soupionis, Lilian Mitrou, Vasilios Katos,”Privacy-preserving, user-centric VoIP CAPTCHA challenges: An integrated solution in the SIP environment.” Information & Computer Security 24.1 (2016): 2-19.
  • Efraimidis, Pavlos S. “Weighted random sampling over data streams.” Algorithms, Probability, Networks, and Games. Springer, LNCS, volume 9295, 2015. 183-195.
    • P.S. Efraimidis. Weighted Random Sampling over Data Streams, Technical Report LPDP-2010-03, Dept. Electrical and Computer Engineering, Democritus University of Thrace (http://arxiv.org/abs/1012.0256).
  • Antonios Chatzitoulousis, Pavlos S. Efraimidis, and Ioannis N. Athanasiadis, Interoperable multimedia annotation and retrieval for the tourism sector, 9th Metadata and Semantics Research Conference (MTSR 2015), pp. 65-76, CCIS 544, Springer.
  • @inproceedings{karagiannis2015social, title={Social network analysis of public lists of POIs}, author={Karagiannis, Ioannis and Arampatzis, Avi and Efraimidis, Pavlos S and Stamatelatos, Giorgos}, booktitle={Proceedings of the 19th Panhellenic Conference on Informatics}, pages={61--62}, year={2015}, organization={ACM}, doi={10.1145/2801948.2802031}, url={https://doi.org/10.1145/2801948.2802031} }
  • Arampatzis, Avi, George Drosatos, and Pavlos S. Efraimidis. “Versatile Query Scrambling for Private Web Search.” Information Retrieval Journal 18.4 (2015): 331-358.
  • M. Tsavli, P.S. Efraimidis, V. Katos, L. Mitrou, Reengineering the user: Privacy concerns about personal data on smartphones, Information Management and Computer Security, 23(4), 394-405, Emerald, 2015.
    • Preliminary results presented in: M. Tsavli, P.S. Efraimidis, V. Katos, Reengineering the user: Privacy concerns about personal data on smartphones, 8th International Symposium on Human Aspects of Information Security & Assurance (HAISA 2014).
  • I.Refanidis, Ch.Emmanouilidis, I.Sakellariou, A.Alexiadis, R.A.Koutsiamanis, K.Agnantis, A.Tasidou, F.Kokkoras and P.S.Efraimidis, myVisitPlannerGR: Personalized Itinerary Planning System for Tourism, accepted in the 8th Hellenic Conference on Artificial Intelligence (SETN 2014).
  • Ioannis Psaroudakis, Vasilios Katos, and Pavlos S. Efraimidis, A novel mechanism for anonymizing GSM calls using a resource based SIP community network, accepted in Security and Communication Networks, Wiley, 2014.
    • Preliminary results presented in SEC 2012: Ioannis Psaroudakis, Vasilios Katos, and Pavlos S. Efraimidis, A framework for anonymizing GSM calls over a smartphone VoIP network, In proceedings of the 27th IFIP International Information Security and Privacy Conference (SEC 2012), Volume 376, 2012, pp 543-548, June 4-6, 2012. (PDF)
  • George Drosatos, Pavlos S. Efraimidis, User-Centric Privacy-Preserving Statistical Analysis of Ubiquitous Health Monitoring Data, accepted in Computer Science and Information Systems, 2014.
  • George Drosatos, Pavlos S. Efraimidis, Ioannis N. Athanasiadis, Ellie D’Hondt and Matthias Stevens, Privacy-Preserving Computation of Participatory Noise Maps in the Cloud, Journal of Systems and Software, Volume 92, Pages 170–183, Elsevier, June 2014.
    • Preliminary results presented in COMPSAC 2012: @inproceedings{NoiseTubePrime, author={George Drosatos and Pavlos S. Efraimidis and Ioannis N. Athanasiadis and Ellie D'Hondt and Matthias Stevens}, booktitle={36th Annual IEEE Computer Software and Applications Conference (COMPSAC 2012)}, title={A privacy-preserving cloud computing system for creating participatory noise maps}, year={2012}, month={july}, isbn = {978-0-7695-4736-7}, location = {Izmir, Turkey}, pages = {581-586}, publisher = {IEEE Computer Society} }
  • Yannis Soupionis, Remous-Aris Koutsiamanis, Pavlos S. Efraimidis, Dimitrios Gritzalis, A game-theoretic analysis of preventing spam over Internet Telephony via audio CAPTCHA-based authentication, accepted in Journal of Computer Security, IOS Press, 2014.
  • TREC 2013 – Contextual Suggestion track: Award winning algorithms for contextual recommendation in the Text Retrieval Conference (TREC) Contextual Suggestion track, November 2013. (Poster Slides BibTex)
  • Pavlos S. Efraimidis and Remous-Aris Koutsiamanis. “Money-based coordination of network packets.” International Conference on Algorithms and Complexity. Springer Berlin Heidelberg, 2013. (PDF)
    • Pavlos S. Efraimidis and Remous-Aris Koutsiamanis. On Money as a Means of Coordination between Network Packets, Technical Report available at http://arxiv.org/abs/1208.3747.
  • Avi Arampatzis, George Drosatos and Pavlos S. Efraimidis. A Versatile Tool for Privacy-Enhanced Web Search, Proceedings of the 35th European Conference on Information Retrieval (ECIR 2013), Moscow, LNCS 7814, pp. 368-379, Springer, 2013. (PDF)
  • Remous-Aris Koutsiamanis and Pavlos S. Efraimidis. A heaviest hitters limiting mechanism with O(1) time complexity for sliding-window data streams, Journal of Internet Technology, Issue Number (ISSN): 1607-9264, 14(1), January 2013, DOI: 10.6138/JIT.2013.14.1.12. (PDF)
  • Avi Arampatzis, Pavlos S. Efraimidis and George Drosatos. A Query Scrambler for Search Privacy on the Internet. Information Retrieval, 16(6): 657-679, Springer, 2013, http://dx.doi.org/10.1007/s10791-012-9212-1, 2012, [IF: 0.914, SJR: 0.053]. (PDF BibTex)
  • George Drosatos and Pavlos S. Efraimidis. An efficient privacy-preserving solution for finding the nearest doctor. Personal and Ubiquitous Computing: Special Issue on Assistive Environments for the Disabled and the Senior Citizens, 2012, in press, [IF: 0.938, SJR: 0.047]. (PDF BibTex)
  • Aimilia Tasidou, Pavlos S. Efraimidis, Yannis Soupionis, Lilian Mitrou, Vasilios Katos, User-centric, Privacy-Preserving Adaptation for VoIP CAPTCHA Challenges, to appear in the 6th International Symposium on Human Aspects of Information Security & Assurance (HAISA 2012).
  • George Drosatos, Aimilia Tasidou and Pavlos Efraimidis. Privacy-Preserving Television Audience Measurement using Smart TVs. In proceedings of the 27th IFIP International Information Security and Privacy Conference (SEC 2012), Volume 376, 2012, pp 223-234, June 4-6, 2012, [Acceptance rate: 25%]. (PDF BibTex)
  • Avi Arampatzis, Pavlos Efraimidis and George Drosatos. Enhancing Deniability against Query-logs. In proceedings of 33rd European Conference on Information Retrieval (ECIR 2011), pp. 117-128, Apr. 2011, [Acceptance rate: 20%]. (PDF BibTex)
  • Lazaros Tsavlidis, Pavlos S. Efraimidis, Remous-Aris Koutsiamanis, Prince: an effective router mechanism for active queue management, to appear in Journal of Internet Engineering, Vol 6, No 1, ISSN 1791-177X. (PDF)
  • Aimilia Tasidou and Pavlos S. Efraimidis, Using Personal Portfolios to Manage Customer Data, 6th DPM International Workshop on Data Privacy Management (DPM 2011), LNCS, Volume 7122, 2012, Pages 141-154.
  • George Drosatos and Pavlos Efraimidis. Privacy-Preserving Statistical Analysis on Ubiquitous Health Data. In proceedings of the 8th international conference on Trust, privacy and security in digital business (TrustBus 2011), LNCS, Volume 6863, 2011, Pages 24-36. (PDF BibTex)
  • Remous-Aris Koutsiamanis, Pavlos S. Efraimidis, An exact and O(1) time heaviest and lightest hitters algorithm for sliding-window data streams, Proceedings of the 5th FTRA International Conference on Multimedia and Ubiquitous Engineering (MUE 2011), IEEE Computer Society, June 28-30, 2011, Pages 89-94. Technical Report available at http://arxiv.org/abs/1103.0116.
  • George Drosatos and Pavlos Efraimidis. Privacy-Enhanced Management of Ubiquitous Health Monitoring Data. In proceedings of 4rd ACM International Conference on PErvasive Technologies Related to Assistive Environments (PETRA 2011), May 25-27, 2011. (PDF BibTex).
  • Grigorios Anagnostopoulos and Pavlos S. Efraimidis. Bayesian Games on a Maxmin Network Router, In Proceedings of Mini-conference on Applied Theoretical Computer Science (MATCOS-10), student session, Koper, Slovenia, October 13th and 14th, 2010, pp. 29-34. (PDF, Proceedings of MATCOS-10)
  • P.S. Efraimidis. (alpha, beta) Fibonacci Search, Technical Report LPDP-2010-02, Dept. Electrical and Computer Engineering, Democritus University of Thrace (http://arxiv.org/abs/1012.0259).
  • P.S. Efraimidis, L. Tsavlidis and G. Mertzios, Window-Games between TCP flows, Theoretical Computer Science (TCS), 411:31-33, pp. 2798-2817, 2010, doi:10.1016/j.tcs.2010.03.031 (Technical Report LPDP-2008-01).
    • Preliminary results presented in SAGT 2008: P.S. Efraimidis, L. Tsavlidis, Lecture Notes in Computer Science (LNCS) 4997, Springer, pages 95-108, 2008. (report, conf version)
  • G. Drosatos and P.S. Efraimidis. A privacy-preserving protocol for finding the nearest doctor in an emergency, 3rd ACM International Conference on PErvasive Technologies Related to Assistive Environments, PETRA 2010, pp. 18:1—8, 2010. (PDF BibTex).
  • Aimilia Tasidou, Pavlos S. Efraimidis and Vasilis Katos, Economics of Personal Data Management: Fair Personal Information Trades, 3rd international conference on e-Democracy (eDemocracy 2009), Lecture Notes of ICST (LNICST), Springer-ICST, Volume 26, 2010, pp 151-160.
  • @inproceedings{stamatelatos2009quantum, AUTHOR = {Georgios Stamatelatos and Georgios Drosatos and Pavlos S. Efraimidis}, TITLE = {Quantum: A Peer-to-Peer Network for Distributed Computations with Enhanced Privacy}, BOOKTITLE = {EYRHKA 2009 Conference Proceedings}, PAGES = {201-210}, ORGANIZATION = {3rd Pan-hellenic Scientific Student Conference on Informatics}, MONTH = {September}, YEAR = {2009} }
  • P.S. Efraimidis, G Drosatos, F. Nalbadis and A. Tasidou, Towards Privacy in Personal Data Management. Information Management & Computer Security (IMCS), Volume 17, Issue 4, pp. 311-329, Emerald, 2009.
    • Preliminary version presented in Panhellenic Conference on Informatics (PCI 2008), Proceedings by IEEE Computer Society, pages 3–7, Aug. 2008 (journal version: PDF BibTex).
  • Pavlos S. Efraimidis and Vasilis Katos, “Probability and Information Theory”, Chapter in the volume “Modern Cryptography: Theory and Applications”, Edited by M. Burmester, S. Gritzalis, S. Katsikas and V. Chrissikopoulos, Publisher: Papasotiriou, Papasotiriou Editions, 2011 (in greek).
  • Dimitrios Kikidis and Pavlos S. Efraimidis, “Privacy issues of the usage of Web Search Engines”, 3rd Conference SFHMMY (Students of Electrical and Computer Engineering Departments conference), 10-11 April 2009, Thessaloniki (conf version in greek). The FireFox AddOn Random Search Engine described in the paper.
  • Sotirios-Aggelos Lenas, Pavlos S. Efraimidis and Vasilis Katos, “Database Forensics”, Technical Report LPDP-2009-2 (in greek). (pdf)
  • Vasilis Katos and Pavlos S. Efraimidis, “Identity Assurance in the Surveillance Society”, chapter in the volume “Privacy Protection in Information and Communication Technologies: Technical and Legal Issues”, Edited by K. Lambrinoudakis, L. Mitrou, S. Gritzalis and S. Katsikas, ISBN 9789607182708, Papasotirou Editions, 2010 (in greek).
  • P.S. Efraimidis, The Complexity of Linear Programming in (\gamma,\kappa)-form, Information Processing Letters, Volume 105, Issue 5, 29 February 2008, Pages 199-201 (report, journal version) .
  • P.S. Efraimidis and P. Spirakis, Weighted Random Sampling, Chapter in Encyclopaedia of Algorithms, Springer 2008 (chapter).
  • G. Papaschinopoulos, G. Stefanidou and P.S. Efraimidis, Existence, uniqueness and asymptotic behavior of the solutions of a fuzzy differential equation with piecewise constant argument, Information Sciences 177 (2007), pp 3855-3870 (journal version).
  • G. Drosatos, P.S. Efraimidis and A. Karakos, Secure Mobile Database Applications: A Case Study, Technical Report LPDP-2007-01 (PDF BibTex).
  • P.S. Efraimidis and P. Spirakis. Approximation schemes for scheduling and covering on unrelated machines, Theoretical Computer Science 359 (1), pp 400-417, 2006 (report, journal version).
  • P.S. Efraimidis and P. Spirakis. Weighted Random Sampling with a Reservoir, Information Processing Letters 97 (5), pp 181-185, 2005 (report, journal version).
  • P.S. Efraimidis and P. Spirakis. Efficient Approximation Algorithms for Scheduling Unrelated Parallel Machines, 1st Balkan Conference in Informatics, pp 122-132, Thessaloniki, Greece, 2003.
  • K. Siozios, P.S. Efraimidis and A. Karakos. Design and implementation of a Secure Mobile IP Architecture, 9th Panhellenic Conference on Informatics, pp 269-279, Thessaloniki, Greece, 2003.
  • P.S. Efraimidis and P. Spirakis. Positive Linear Programming extensions: Parallel Complexity and Applications. Proc. EuroPAR 2000, August 30 – September 1, 2000, Technical University of Munich, Germany, Lecture Notes in Computer Science 1900: pp. 456-460, Springer 2000, ISBN 3-540-67956-1.
  • P.S. Efraimidis and P. Spirakis. The Lagrangian Search Method (LSM): Applying Lagrangian relaxation to approximately solved restricted linear programs. Chapter in Advances in Convex Analysis and Global Optimization: Honoring the Memory of C. Caratheodory (1873-1950), N. Hadjisavvas and P. Pardalos (eds.), Dordrecht, Kluwer Academic Publishers, Aug. 2001.
  • P.S. Efraimidis and P. Spirakis. Combinatorial Randomized Rounding: Boosting Randomized Rounding with Combinatorial Arguments, Chapter in the Book “Stochastic optimization: algorithms and applications”, (Gainesville, FL, 2000), S. Uryasev and P. Pardalos (eds.), pp. 31-53, Kluwer Academic Publishers, Dordrecht, 2001.
  • P.S. Efraimidis and P. Spirakis. Randomized Approximation Schemes for Scheduling Unrelated Parallel Machines. Electronic Colloquium on Computational Complexity (ECCC), TR 00-007, 2000.
  • P.S. Efraimidis, C. Glymidakis, B. Mamalis, P. Spirakis, and B. Tampakas. Parallel Text Retrieval on a High Performance Super Computer Using the Vector Space Model. ACM SIGIR 1995: 58-66, Seattle, WA.
  • S. Walter, S. Volmer and P.S. Efraimidis: Parallel Rendering of 3D Ultrasound at Interactive Rates. Proc. 1st EUROGRAPHICS Workshop for Parallel Graphics and Visualization, pp. 189-202, Bristol, September 1996.

NOTE: The documents contained on this page have been provided by the contributing authors as a means to ensure timely dissemination of scholarly and technical work on a non-commercial basis. Copyright and all rights therein are maintained by the authors or by other copyright holders, notwithstanding that they have offered their works here electronically. It is understood that all persons copying this information will adhere to the terms and constraints invoked by each author’s copyright. These works may not be reposted without the explicit permission of the copyright holder.