@conference {819,
	title = {SodaSense: An Intelligence Platform for Micro-Mobility, Micro-Climate and Agriculture},
	booktitle = {Proceedings of the GEOProcessing 2023},
	year = {2023},
	abstract = {<p>SODASENSE is an end-to-end big data manipulation platform that focuses on decision and policy making. It concerns the management of big trajectory and spatio-temporal data that is collected from sensors and relates to micro-mobility, microclimate and agriculture, and aims to the creation of an expert decision making platform with research, social and business orientation.</p>
},
	keywords = {big data management and analysis, spatial time series, trajectories},
	author = {Paraskevi Raftopoulou and Spiros Skiadopoulos and Christos Tryfonopoulos and Costas Vasilakis}
}
@conference {DBLP:conf/debs/ChantziosZST19,
	title = {Ping - A customizable, open-source information filtering system for textual data},
	booktitle = {Proceedings of the 13th ACM International Conference on Distributed and Event-based Systems, DEBS 2019, Darmstadt, Germany, June 24-28, 2019.},
	year = {2019},
	pages = {228{\textendash}231},
	doi = {10.1145/3328905.3332512},
	url = {https://doi.org/10.1145/3328905.3332512},
	author = {Thanasis Chantzios and Lefteris Zervakis and Spiros Skiadopoulos and Christos Tryfonopoulos}
}
@conference {588,
	title = {The quest for the appropriate cyber-threat intelligence sharing platform},
	booktitle = {Proceedings of the 8th International Conference on Data Science, Technology and Applications (DATA), Prague, Czech Republic},
	year = {2019},
	month = { 07/2009},
	abstract = {Cyber-threat intelligence (CTI) is any information that can help an organization identify, assess, monitor, and respond to cyber-threats. It relates to all cyber components of an organization such as networks, computers, and other types of information technology. In the recent years, due to the major increase of cyber-threats, CTI sharing is becoming increasingly important both as a subject of research and as a concept of providing additional security to organizations. However, selecting the proper tools and platforms for CTI sharing, is a challenging task, that pertains to a variety of aspects. In this paper, we start by overviewing the CTI procedure (threat types, categories, sources and the general CTI life-cycle). Then, we present a set of seven high-level CTI platform recommendations that can be used to evaluate a platform and subsequently we survey six state-of- the-art cyber-threat intelligence platforms. Finally, we compare and evaluate the six aforementioned platforms by means of the earlier proposed recommendations.},
	keywords = {Cyber-threat, Intelligence, Sharing},
	url = {http://users.uop.gr/~trifon/papers/pdf/data19-CKSKTBK.pdf},
	author = {Thanasis Chantzios and Paris Koloveas and Spiros Skiadopoulos and Nikos Kolokotronis and Christos Tryfonopoulos and Vasiliki-Georgia Bilali and Dimitris Kavallieros}
}
@article {581,
	title = {Query Reorganisation Algorithms for Efficient Boolean Information Filtering},
	journal = {IEEE Transactions on Knowledge and Data Engineering},
	volume = {29},
	year = {2017},
	pages = {418{\textendash}432},
	abstract = {In the information filtering paradigm, clients subscribe to a server with continuous queries that express their information needs and get notified every time appropriate information is published. To perform this task in an efficient way, servers employ indexing schemes that support fast matches of the incoming information with the query database. Such indexing schemes involve (i) main-memory trie-based data structures that cluster similar queries by capturing common elements between them and (ii) efficient filtering mechanisms that exploit this clustering to achieve high throughput and low filtering times. However, state-of-the-art indexing schemes are sensitive to the query insertion order and cannot adopt to an evolving query workload, degrading the filtering performance over time. In this paper, we present an adaptive trie-based algorithm that outperforms current methods by relying on query statistics to reorganise the query database. Contrary to previous approaches, we show that the nature of the constructed tries, rather than their compactness, is the determining factor for efficient filtering performance. Our algorithm does not depend on the order of insertion of queries in the database, manages to cluster queries even when clustering possibilities are limited, and achieves more than 96\% filtering time improvement over its state-of-the-art competitors. Finally, we demonstrate that our solution is easily extensible to multi-core machines.},
	keywords = {dissemination, indexing methods, Information filtering, user profiles and alert services},
	doi = {10.1109/TKDE.2016.2620140},
	url = {https://doi.org/10.1109/TKDE.2016.2620140},
	author = {Lefteris Zervakis and Christos Tryfonopoulos and Spiros Skiadopoulos and Manolis Koubarakis}
}
@conference {591,
	title = {A crawler architecture for harvesting the clear, social, and dark web for IoT-related cyber-threat intelligence},
	booktitle = {In Proceedings of the IEEE Workshop on Cyber Security \& Resilience in the Internet of Things (CSRIoT @ IEEE Services)},
	year = {2016},
	month = {July 2016},
	publisher = {IEEE},
	organization = {IEEE},
	address = {Milan, Italy},
	abstract = {The clear, social, and dark web have lately been identified as rich sources of valuable cyber-security information that {\textendash}given the appropriate tools and methods{\textendash} may be identified, crawled and subsequently leveraged to actionable cyber- threat intelligence. In this work, we focus on the information gathering task, and present a novel crawling architecture for transparently harvesting data from security websites in the clear web, security forums in the social web, and hacker fo- rums/marketplaces in the dark web. The proposed architecture adopts a two-phase approach to data harvesting. Initially a machine learning-based crawler is used to direct the harvesting towards websites of interest, while in the second phase state- of-the-art statistical language modelling techniques are used to represent the harvested information in a latent low-dimensional feature space and rank it based on its potential relevance to the task at hand. The proposed architecture is realised using exclusively open-source tools, and a preliminary evaluation with crowdsourced results demonstrates its effectiveness.},
	keywords = {crawling architecture, cyber-security, cyber-threat intelligence, IoT, language models, Machine Learning},
	url = {http://users.uop.gr/ trifon/papers/pdf/csriot19-KCTS.pdf},
	author = {Paris Koloveas and Thanasis Chantzios and Christos Tryfonopoulos and Spiros Skiadopoulos}
}
@conference {DBLP:conf/esws/ZervakisTSK16,
	title = {Full-Text Support for Publish/Subscribe Ontology Systems},
	booktitle = {The Semantic Web. Latest Advances and New Domains - 13th International Conference, ESWC 2016, Heraklion, Crete, Greece, May 29 - June 2, 2016, Proceedings},
	year = {2016},
	pages = {233{\textendash}249},
	doi = {10.1007/978-3-319-34129-3_15},
	url = {https://doi.org/10.1007/978-3-319-34129-3_15},
	author = {Lefteris Zervakis and Christos Tryfonopoulos and Spiros Skiadopoulos and Manolis Koubarakis}
}
@conference {DBLP:conf/edbt/ZervakisTSSS16,
	title = {Towards Publish/Subscribe Functionality on Graphs},
	booktitle = {Proceedings of the Workshops of the EDBT/ICDT 2016 Joint Conference, EDBT/ICDT Workshops 2016, Bordeaux, France, March 15, 2016.},
	year = {2016},
	url = {http://ceur-ws.org/Vol-1558/paper13.pdf},
	author = {Lefteris Zervakis and Christos Tryfonopoulos and Vinay Setty and Stephan Seufert and Spiros Skiadopoulos}
}
@conference {563,
	title = {Cloud-Based Data and Knowledge Management for Multi-Centre Biomedical Studies},
	booktitle = {Proceedings of the International Conference on Knowledge Capture (K-CAP)},
	year = {2015},
	month = {October 7-10},
	address = {Palisades NY, USA},
	abstract = {Among the basic research tools for (bio)medical science are epidemiological studies that typically involve a number of hospitals, clinics, and research centres scattered around the world, and are often referred to as multi-centre studies. Clearly, the effectiveness and importance of a multi-centre study increases with the number of participating centres and enrolled patients, but at the same time this natural distribution in the production of research data requires sophisticated data management infrastructures to support the participating units. This kind of infrastructure is not only expensive to build and maintain, but also cannot be reused as it is often tailored to a specific study. In this work, we present a cloud-based system, coined CLOUDSTUDY, that allows users without any computer science background to design, deploy, and administer platforms aimed for managing, sharing, and analysing clinical data from multi-centre studies. The CLOUDSTUDY system provides a zero-administration, zero-cost online tool for creating multi- centre studies that (i) enhances re-usability by introducing study templates, (ii) supports (bio)medical needs through specialised data types, and (iii) emphasises data filtering/export through an expressive yet simple graphical query engine.},
	doi = {10.1145/2815833.2816949},
	url = {https://doi.org/10.1145/2815833.2816949},
	author = {Amalia Tsafara and Christos Tryfonopoulos and Spiros Skiadopoulos and Lefteris Zervakis}
}
@conference {DBLP:conf/kcap/TsafaraTSZ15,
	title = {Cloud-Based Data and Knowledge Management for Multi-Centre Biomedical Studies},
	booktitle = {Proceedings of the 8th International Conference on Knowledge Capture, K-CAP 2015, Palisades, NY, USA, October 7-10, 2015},
	year = {2015},
	pages = {24:1{\textendash}24:4},
	doi = {10.1145/2815833.2816949},
	url = {https://doi.org/10.1145/2815833.2816949},
	author = {Amalia Tsafara and Christos Tryfonopoulos and Spiros Skiadopoulos and Lefteris Zervakis}
}
@inbook {DBLP:books/sp/15/PoulisGLST15,
	title = {SECRETA: A Tool for Anonymizing Relational, Transaction and RT-Datasets},
	booktitle = {Medical Data Privacy Handbook},
	year = {2015},
	pages = {83{\textendash}109},
	doi = {10.1007/978-3-319-23633-9_5},
	url = {https://doi.org/10.1007/978-3-319-23633-9_5},
	author = {Giorgos Poulis and Aris Gkoulalas-Divanis and Grigorios Loukides and Spiros Skiadopoulos and Christos Tryfonopoulos}
}
@inbook {565,
	title = {SECRETA: A Tool for Anonymizing Relational, Transaction and RT-Datasets},
	booktitle = {Medical Data Privacy Handbook},
	year = {2015},
	pages = {83-109},
	publisher = {Springer},
	organization = {Springer},
	author = {Giorgos Poulis and Aris Gkoulalas-Divanis and Grigorios Loukides and Spiros Skiadopoulos and Christos Tryfonopoulos},
	editor = {Aris Gkoulalas-Divanis and Grigorios Loukides}
}
@conference {DBLP:conf/edbt/PoulisGLST14,
	title = {SECRETA: A System for Evaluating and Comparing RElational and Transaction Anonymization algorithms},
	booktitle = {Proceedings of the 17th International Conference on Extending Database Technology, EDBT 2014, Athens, Greece},
	year = {2014},
	month = {March 24-28},
	pages = {620{\textendash}623},
	doi = {10.5441/002/edbt.2014.58},
	url = {https://doi.org/10.5441/002/edbt.2014.58},
	author = {Giorgos Poulis and Aris Gkoulalas-Divanis and Grigorios Loukides and Spiros Skiadopoulos and Christos Tryfonopoulos}
}
@conference {DBLP:conf/bibe/TsafaraTS13,
	title = {CloudStudy: A cloud-based system for supporting multi-centre studies},
	booktitle = {13th IEEE International Conference on BioInformatics and BioEngineering, BIBE 2013, Chania, Greece, November 10-13, 2013},
	year = {2013},
	pages = {1{\textendash}4},
	doi = {10.1109/BIBE.2013.6701549},
	url = {https://doi.org/10.1109/BIBE.2013.6701549},
	author = {Amalia Tsafara and Christos Tryfonopoulos and Spiros Skiadopoulos}
}
@article {DBLP:journals/corr/ZervakisTPKS13,
	title = {Full-text Support for Publish/Subscribe Ontology Systems},
	journal = {CoRR},
	volume = {abs/1307.2015},
	year = {2013},
	url = {http://arxiv.org/abs/1307.2015},
	author = {Lefteris Zervakis and Christos Tryfonopoulos and Antonios Papadakis-Pesaresi and Manolis Koubarakis and Spiros Skiadopoulos}
}
@conference {554,
	title = {Full-text Support for Publish/Subscribe Ontology Systems},
	booktitle = {Proceedings of the Extended Semantic Web Conference (ESWC)},
	year = {2012},
	month = {May},
	address = {Crete, Greece},
	author = {Lefteris Zervakis and Christos Tryfonopoulos and Antonios Papadakis-Pesaresi and Manolis Koubarakis and Spiros Skiadopoulos}
}
@article {DBLP:journals/tkde/KoubarakisST06,
	title = {Logic and Computational Complexity for Boolean Information Retrieval},
	journal = {IEEE Trans. Knowl. Data Eng.},
	volume = {18},
	number = {12},
	year = {2006},
	pages = {1659{\textendash}1666},
	doi = {10.1109/TKDE.2006.193},
	url = {https://doi.org/10.1109/TKDE.2006.193},
	author = {Manolis Koubarakis and Spiros Skiadopoulos and Christos Tryfonopoulos}
}
