@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 {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}
}
@article {582,
	title = {Distributed Large-Scale Information Filtering},
	journal = {Transactions on Large-Scale Data- and Knowledge-Centered Systems (TLDKS)},
	volume = {13},
	year = {2014},
	pages = {91{\textendash}122},
	abstract = {We study the problem of distributed resource sharing in peer-to-peer networks and focus on the problem of information filter- ing. In our setting, subscriptions and publications are specified using an expressive attribute-value representation that supports both the Boolean and Vector Space models. We use an extension of the distributed hash table Chord to organise the nodes and store user subscriptions, and utilise efficient publication protocols that keep the network traffic and latency low at filtering time. To verify our approach, we evaluate the proposed protocols experimentally using thousands of nodes, millions of user subscriptions, and two different real-life corpora. We also study three important facets of the load-balancing problem in such a scenario and present a novel algorithm that manages to distribute the load evenly among the nodes. Our results show that the designed protocols are scalable and efficient: they achieve expressive information filtering functionality with low message traffic and latency.},
	keywords = {distributed hash tables, Information management, publish/subscribe},
	author = {Christos Tryfonopoulos and Stratos Idreos and Manolis Koubarakis and Paraskevi Raftopoulou}
}
@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 {583,
	title = {Information Filtering and Query Indexing for an Information Retrieval Model},
	journal = {ACM Transactions on Information Systems (TOIS)},
	volume = {27},
	year = {2009},
	pages = {1{\textendash}47},
	author = {Christos Tryfonopoulos and Manolis Koubarakis and Yannis Drougas}
}
@conference {586,
	title = {Approximate Information Filtering in Peer-to-Peer Networks},
	booktitle = {Proceedings of the 9th Web Information Systems Engineering (WISE) Conference},
	year = {2008},
	month = {September},
	address = {Auckland, New Zealand},
	author = {Christian Zimmer and Christos Tryfonopoulos and Klaus Berberich and Manolis Koubarakis and Gerhard Weikum}
}
@article {557,
	title = {Architectural Alternatives for Information Filtering in Structured Overlay Networks},
	journal = {IEEE Internet Computing},
	volume = {11},
	year = {2007},
	pages = {24-34},
	author = {Christos Tryfonopoulos and Christian Zimmer and Manolis Koubarakis and Gerhard Weikum}
}
@article {DBLP:journals/tkde/SkiadopoulosSSK07a,
	title = {Correction to "A Family of Directional Relation Models for Extended Objects"},
	journal = {IEEE Trans. Knowl. Data Eng.},
	volume = {19},
	number = {10},
	year = {2007},
	pages = {1448},
	doi = {10.1109/TKDE.2007.190653},
	url = {https://doi.org/10.1109/TKDE.2007.190653},
	author = {Spiros Skiadopoulos and Nikos Sarkas and Timos K. Sellis and Manolis Koubarakis}
}
@article {DBLP:journals/tkde/SkiadopoulosSSK07,
	title = {A Family of Directional Relation Models for Extended Objects},
	journal = {IEEE Trans. Knowl. Data Eng.},
	volume = {19},
	number = {8},
	year = {2007},
	pages = {1116{\textendash}1130},
	doi = {10.1109/TKDE.2007.1046},
	url = {https://doi.org/10.1109/TKDE.2007.1046},
	author = {Spiros Skiadopoulos and Nikos Sarkas and Timos K. Sellis and Manolis Koubarakis}
}
@conference {564,
	title = {Node Behavior Prediction for Large-Scale Approximate Information Filtering},
	booktitle = {Proceedings of the International Workshop on Large-Scale Distributed Systems for Information Retrieval (LSDS-IR @ SIGIR)},
	year = {2007},
	month = {July},
	address = {Amsterdam, The Netherlands},
	author = {Christian Zimmer and Christos Tryfonopoulos and Klaus Berberich and Gerhard Weikum and Manolis Koubarakis}
}
@conference {559,
	title = {Distributed Evaluation of Continuous Equi-join Queries over Large Structured Overlay Networks},
	booktitle = {Proceedings of the 22nd International Conference on Data Engineering (ICDE)},
	year = {2006},
	month = {April},
	address = {Atlanda, USA},
	author = {Stratos Idreos and Christos Tryfonopoulos and Manolis Koubarakis}
}
@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}
}
@conference {adpuc06-BKTWZ,
	title = {MAPS: Approximate Publish/Subscribe Functionality in Peer-to-Peer Networks},
	booktitle = {Proceedings of Advanced Data Processing in Ubiquitous Computing Workshop (ADPUC @ Middleware)},
	year = {2006},
	month = {November},
	pages = {1{\textendash}6},
	address = {Melbourne, Australia},
	author = {Klaus Berberich and Manolis Koubarakis and Christos Tryfonopoulos and Gerhard Weikum and Christian Zimmer}
}
@article {DBLP:journals/tkde/SkiadopoulosGSVSK05,
	title = {Computing and Managing Cardinal Direction Relations},
	journal = {IEEE Trans. Knowl. Data Eng.},
	volume = {17},
	number = {12},
	year = {2005},
	pages = {1610{\textendash}1623},
	doi = {10.1109/TKDE.2005.192},
	url = {https://doi.org/10.1109/TKDE.2005.192},
	author = {Spiros Skiadopoulos and Christos Giannoukos and Nikos Sarkas and Panos Vassiliadis and Timos K. Sellis and Manolis Koubarakis}
}
@article {DBLP:journals/ai/SkiadopoulosK05,
	title = {On the consistency of cardinal direction constraints},
	journal = {Artif. Intell.},
	volume = {163},
	number = {1},
	year = {2005},
	pages = {91{\textendash}135},
	doi = {10.1016/j.artint.2004.10.010},
	url = {https://doi.org/10.1016/j.artint.2004.10.010},
	author = {Spiros Skiadopoulos and Manolis Koubarakis}
}
@article {593,
	title = {Fair Resource Allocation in a Simple Multi-Agent Setting: Search Algorithms and Experimental Evaluation},
	journal = {International Journal on Artificial Intelligence Tools (IJAIT)},
	volume = {14},
	year = {2005},
	month = {December},
	pages = {887{\textendash}899},
	abstract = {We study the problem of fair resource allocation in a simple cooperative multi-agent setting where we have k agents and a set of n objects to be allocated to those agents. Each object is associated with a weight represented by a positive integer or real number. We would like to allocate all objects to the agents so that each object is allocated to only one agent and the weight is distributed fairly. We adopt the fairness index popularized by the networking community as our measure of fairness, and study centralized algorithms for fair resource allocation. Based on the relationship between our problem and number partitioning, we devise a greedy algorithm for fair resource allocation that runs in polynomial time but is not guaranteed to find the optimal solution, and a complete anytime algorithm that finds the optimal solution but runs in exponential time. Then we study the phase transition behavior of the complete algorithm. Finally, we demonstrate that the greedy algorithm actually performs very well and returns almost perfectly fair allocations.},
	keywords = {Fairness; resource allocation; number partitioning; phase transitions},
	author = {Paraskevi Raftopoulou and Manolis Koubarakis and Kostas Stergiou and Peter Triantafillou}
}
@conference {547,
	title = {LibraRing: An Architecture for Distributed Digital Libraries Based on DHTs},
	booktitle = {Proceedings of the 9th European Conference on Research and Advanced Technology for Digital Libraries (ECDL)},
	year = {2005},
	month = {September},
	address = {Vienna, Austria},
	author = {Christos Tryfonopoulos and Stratos Idreos and Manolis Koubarakis}
}
@conference {542,
	title = {Publish/Subscribe Functionalities for Future Digital Libraries using Structured Overlay Networks},
	booktitle = {Proceedings of the 8th International Workshop of the DELOS Network of Excellence on Digital Libraries on Future Digital Library Management Systems},
	year = {2005},
	month = {March},
	address = {Schloss Dagstuhl, Germany},
	author = {Christos Tryfonopoulos and Stratos Idreos and Manolis Koubarakis}
}
@conference {573,
	title = {Publish/Subscribe Functionality in IR Environments using Structured Overlay Networks},
	booktitle = {Proceedings of the 28th Annual International ACM SIGIR Conference},
	year = {2005},
	month = {August},
	address = {Salvador, Brazil},
	author = {Christos Tryfonopoulos and Stratos Idreos and Manolis Koubarakis}
}
@proceedings {DBLP:conf/edbt/2004,
	title = {Advances in Database Technology - EDBT 2004, 9th International Conference on Extending Database Technology, Heraklion, Crete, Greece, March 14-18, 2004, Proceedings},
	volume = {2992},
	year = {2004},
	publisher = {Springer},
	isbn = {3-540-21200-0},
	doi = {10.1007/b95855},
	url = {https://doi.org/10.1007/b95855},
	editor = {Elisa Bertino and Stavros Christodoulakis and Dimitris Plexousakis and Vassilis Christophides and Manolis Koubarakis and Klemens B{\"o}hm and Elena Ferrari}
}
@article {DBLP:journals/ai/SkiadopoulosK04,
	title = {Composing cardinal direction relations},
	journal = {Artif. Intell.},
	volume = {152},
	number = {2},
	year = {2004},
	pages = {143{\textendash}171},
	doi = {10.1016/S0004-3702(03)00137-1},
	url = {https://doi.org/10.1016/S0004-3702(03)00137-1},
	author = {Spiros Skiadopoulos and Manolis Koubarakis}
}
@conference {DBLP:conf/edbt/SkiadopoulosGVSK04,
	title = {Computing and Handling Cardinal Direction Information},
	booktitle = {Advances in Database Technology - EDBT 2004, 9th International Conference on Extending Database Technology, Heraklion, Crete, Greece, March 14-18, 2004, Proceedings},
	year = {2004},
	pages = {329{\textendash}347},
	doi = {10.1007/978-3-540-24741-8_20},
	url = {https://doi.org/10.1007/978-3-540-24741-8_20},
	author = {Spiros Skiadopoulos and Christos Giannoukos and Panos Vassiliadis and Timos K. Sellis and Manolis Koubarakis}
}
@conference {571,
	title = {Distributed Resource Sharing using Self-Organized Peer-to-Peer Networks and Languages from Information Retrieval},
	booktitle = {Proceedings of the International Workshop on Self-* Properties in Complex Information Systems (Self-*)},
	year = {2004},
	month = {May},
	address = {Bertinoro, Italy},
	author = {Christos Tryfonopoulos and Manolis Koubarakis}
}
@conference {568,
	title = {Implementing Publish/Subscribe Systems with Languages from Information Retrieval on Top of Structured Overlay Networks},
	booktitle = {Proceedings of the International Workshop on Peer-to-Peer and IR (P2P\&IR @ SIGIR)},
	year = {2004},
	month = {July},
	address = {Sheffield, UK},
	author = {Christos Tryfonopoulos and Manolis Koubarakis}
}
@conference {576,
	title = {P2P-DIET: An Extensible P2P Service that Unifies Ad-hoc and Continuous Querying in Super-Peer Networks},
	booktitle = {Proceedings of the ACM SIGMOD Conference},
	year = {2004},
	month = {June},
	address = {Paris, France},
	author = {Stratos Idreos and Manolis Koubarakis and Christos Tryfonopoulos}
}
@conference {551,
	title = {P2P-DIET: One-Time and Continuous Queries in Super-Peer Networks},
	booktitle = {Proceedings of the 9th International Conference on Extending Database Technology (EDBT)},
	year = {2004},
	month = {March},
	address = {Heraklion, Greece},
	author = {Stratos Idreos and Manolis Koubarakis and Christos Tryfonopoulos}
}
@conference {585,
	title = {Publish/Subscribe Systems with Distributed Hash Tables and Languages from Information Retrieval},
	booktitle = {Proceedings of the 6th Workshop on Distributed Data and Structures (WDAS)},
	year = {2004},
	month = {July},
	address = {Lausanne, Switzerland},
	author = {Christos Tryfonopoulos and Manolis Koubarakis}
}
@conference {567,
	title = {Query Processing in Super-Peer Networks with Languages Based on Information Retrieval: the P2P-DIET Approach},
	booktitle = {Proceedings of the International Workshop on Peer-to-peer Computing and Databases (P2P\&DB @ EDBT)},
	year = {2004},
	month = {March},
	address = {Herakion, Greece},
	author = {Stratos Idreos and Christos Tryfonopoulos and Manolis Koubarakis and Yannis Drougas}
}
@article {577,
	title = {Selective Information Dissemination in P2P Networks: Problems and Solutions},
	journal = {SIGMOD Record, Special Issue on Peer-to-Peer Data Management},
	volume = {32},
	year = {2003},
	pages = {71-76},
	author = {Manolis Koubarakis and Christos Tryfonopoulos and Stratos Idreos and Yannis Drougas},
	editor = {Karl Aberer}
}
@proceedings {DBLP:conf/chorochronos/2003,
	title = {Spatio-Temporal Databases: The CHOROCHRONOS Approach},
	volume = {2520},
	year = {2003},
	publisher = {Springer},
	isbn = {3-540-40552-6},
	doi = {10.1007/b83622},
	url = {https://doi.org/10.1007/b83622},
	editor = {Manolis Koubarakis and Timos K. Sellis and Andrew U. Frank and St{\'e}phane Grumbach and Ralf Hartmut G{\"u}ting and Christian S. Jensen and Nikos A. Lorentzos and Yannis Manolopoulos and Enrico Nardelli and Barbara Pernici and Hans-J{\"o}rg Schek and Michel Scholl and Babis Theodoulidis and Nectaria Tryfona}
}
@conference {DBLP:conf/chorochronos/GrumbachKRSS03,
	title = {Spatio-temporal Models and Languages: An Approach Based on Constraints},
	booktitle = {Spatio-Temporal Databases: The CHOROCHRONOS Approach},
	year = {2003},
	pages = {177{\textendash}201},
	doi = {10.1007/978-3-540-45081-8_5},
	url = {https://doi.org/10.1007/978-3-540-45081-8_5},
	author = {St{\'e}phane Grumbach and Manolis Koubarakis and Philippe Rigaux and Michel Scholl and Spiros Skiadopoulos}
}
@conference {DBLP:conf/cp/SkiadopoulosK02,
	title = {Consistency Checking for Qualitative Spatial Reasoning with Cardinal Directions},
	booktitle = {Principles and Practice of Constraint Programming - CP 2002, 8th International Conference, CP 2002, Ithaca, NY, USA, September 9-13, 2002, Proceedings},
	year = {2002},
	pages = {341{\textendash}355},
	doi = {10.1007/3-540-46135-3_23},
	url = {https://doi.org/10.1007/3-540-46135-3_23},
	author = {Spiros Skiadopoulos and Manolis Koubarakis}
}
@conference {536,
	title = {Data Models and Languages for Agent-Based Textual Information Dissemination},
	booktitle = {Proceedings of the 6th International Workshop on Cooperative Information Agents (CIA)},
	year = {2002},
	month = {September},
	publisher = {Springer},
	organization = {Springer},
	address = {Madrid, Spain},
	author = {Manolis Koubarakis and Christos Tryfonopoulos and Paraskevi Raftopoulou and Theodoros Koutris}
}
@conference {572,
	title = {Efficient Agent-Based Dissemination of Textual Information},
	booktitle = {Proceedings of the 2nd Hellenic Conference on Artificial Intelligence (SETN)},
	year = {2002},
	month = {April},
	address = {Thessaloniki, Greece},
	author = {Manolis Koubarakis and Theodoros Koutris and Paraskevi Raftopoulou and Christos Tryfonopoulos}
}
@conference {546,
	title = {Information Alert in Distributed Digital Libraries: The Models, Languages, and Architecture of DIAS},
	booktitle = {Proceedings of the 6th European Conference on Research and Advanced Technology for Digital Libraries (ECDL)},
	year = {2002},
	month = {September},
	address = {Rome, Italy},
	author = {Manolis Koubarakis and Theodoros Koutris and Christos Tryfonopoulos and Paraskevi Raftopoulou}
}
@conference {584,
	title = {Peer-to-peer Agent Systems for Textual Information Dissemination: Algorithms and Complexity},
	booktitle = {Proceedings of the UK Workshop on Multiagent Systems (UKMAS)},
	year = {2002},
	month = {December},
	address = {Liverpool, UK},
	author = {Manolis Koubarakis and Christos Tryfonopoulos}
}
@conference {aisb01-MKL+,
	title = {Agents in Decentralised Information Ecosystems: The DIET Approach},
	booktitle = {Proccedings of the Symposium on Information Agents for E-Commerce, AISB Convention},
	year = {2001},
	month = {March},
	pages = {109{\textendash}117},
	address = {York, UK},
	author = {P. Marrow and Manolis Koubarakis and R.H. van Lengen and F. Valverde-Albacete and E. Bonsma and J. Cid-Suerio and A.R. Figueiras-Vidal and A. Gallardo-Antolin and C. Hoile and T. Koutris and H. Molina-Bulla and A. Navia-Vazquez and Paraskevi Raftopoulou and N. Skarmeas and Christos Tryfonopoulos and F. Wang and C. Xiruhaki}
}
@conference {599,
	title = {Agents in Decentralised Information Ecosystems: The DIET Approach},
	booktitle = {Symposium on Information Agents for E-Commerce, AISB Convention},
	year = {2001},
	month = {March},
	address = {University of York, United Kingdom},
	abstract = {The complexity of the current global information infrastructure requires novel means of understanding and exploiting the dynamics of information. One means may be through the concept of an information ecosystem. An information ecosystem is analogous to a natural ecosystem in which there are flows of materials and energy analogous to information flow between many interacting individuals. This paper describes a multi-agent platform, DIET (Decentralised Information Ecosystem Technologies) that can be used to implement open, robust, adaptive and scalable ecosystem-inspired systems. We describe the design principles of the DIET software architecture, and present a simple example application based upon it. We go on to consider how the DIET system can be used to develop information brokering agents, and how these can contribute to the implementation of economic interactions between agents, as well as identifying some open questions relating to research in these areas. In this way we show the capacity of the DIET system to support applications using information agents.},
	author = {P. Marrow and Manolis Koubarakis and R.H. van Lengen and F. Valverde-Albacete and E. Bonsma and J. Cid-Suerio and A.R. Figueiras-Vidal and A. Gallardo-Antolin and C. Hoile and T. Koutris and H. Molina-Bulla and A. Navia-Vazquez and Paraskevi Raftopoulou and N. Skarmeas and Christos Tryfonopoulos and F. Wang and C. Xiruhaki}
}
@conference {DBLP:conf/ssd/SkiadopoulosK01,
	title = {Composing Cardinal Direction Relations},
	booktitle = {Advances in Spatial and Temporal Databases, 7th International Symposium, SSTD 2001, Redondo Beach, CA, USA, July 12-15, 2001, Proceedings},
	year = {2001},
	pages = {299{\textendash}320},
	doi = {10.1007/3-540-47724-1_16},
	url = {https://doi.org/10.1007/3-540-47724-1_16},
	author = {Spiros Skiadopoulos and Manolis Koubarakis}
}
@article {DBLP:journals/ai/KoubarakisS00,
	title = {Querying temporal and spatial constraint networks in PTIME},
	journal = {Artif. Intell.},
	volume = {123},
	number = {1-2},
	year = {2000},
	pages = {223{\textendash}263},
	doi = {10.1016/S0004-3702(00)00055-2},
	url = {https://doi.org/10.1016/S0004-3702(00)00055-2},
	author = {Manolis Koubarakis and Spiros Skiadopoulos}
}
@conference {DBLP:conf/aaai/KoubarakisS99,
	title = {Querying Temporal Constraint Networks in PTIME},
	booktitle = {Proceedings of the Sixteenth National Conference on Artificial Intelligence and Eleventh Conference on Innovative Applications of Artificial Intelligence, July 18-22, 1999, Orlando, Florida, USA.},
	year = {1999},
	pages = {745{\textendash}750},
	url = {http://www.aaai.org/Library/AAAI/1999/aaai99-106.php},
	author = {Manolis Koubarakis and Spiros Skiadopoulos}
}
@conference {DBLP:conf/stdbm/KoubarakisS99,
	title = {Tractable Query Answering in Indefinite Constraint Databases: Basic Results and Applications to Querying Spatiotemporal Information},
	booktitle = {Spatio-Temporal Database Management, International Workshop STDBM{\textquoteright}99, Edinburgh, Scotland, September 10-11, 1999, Proceedings},
	year = {1999},
	pages = {204{\textendash}223},
	doi = {10.1007/3-540-48344-6_12},
	url = {https://doi.org/10.1007/3-540-48344-6_12},
	author = {Manolis Koubarakis and Spiros Skiadopoulos}
}
