@article {851, title = {Security Issues in Brain {\textendash} Computer Interfaces (BCI)}, journal = {Hellenic Journal of Nursing}, volume = {TBD}, year = {2025}, abstract = {

Introduction: Brain-computer interface (BCI) systems emerged to harness and interpret the electrical activity of the brain for interaction with external devices. BCI, or Brain-Machine Interface (BMI), integrates hardware and software to facilitate human-environment interaction, independently of peripheral nerves and muscles, through control signals from electroencephalographic data. However, in the area of ​​security, BCI systems remain underdeveloped. The importance of security in BCI systems has only recently attracted attention, leading to the emergence of terms such as neurosecurity and neuroethics. The literature has identified categories of security threats that affect the integrity and confidentiality of BCI, however, comprehensive research on these issues is still lacking. Purpose: The purpose of this literature review is to describe the potential security attacks that affect each phase of the life cycle of a BCI system. Also, the analysis of the impacts of these attacks as well as the possible countermeasures that can be used and how they are documented based on the international literature. Material and Method: A narrative literature review was conducted based on articles from scientific databases (PubMed /Medline, Google Scholar) using specific keywords in Greek and English, in printed books and online references. Results: A critical review of the literature reveals that the security field focused on BCI system technologies is not yet mature, creating opportunities for malicious actors to launch attacks. Even unsophisticated attacks can however have a significant impact on both BCI system technologies and user security. In addition, the development of standardization initiatives for the unification of BCI systems in terms of information is recognized as an opportunity. Well-studied areas such as implantable medical devices and the Internet of Things can provide guidance for the development of robust security mechanisms, while user awareness of security issues in BCI systems is considered crucial. Conclusions: Significant advances in BCI research have occurred over the past two decades, leveraging established methodologies in signal processing and pattern recognition. Many studies have improved the accuracy of BCI and proposed methods for efficient information transfer, despite challenges in brain signal processing. As a result, user training time has been reduced, facilitating broader application of BCI for people with disabilities, including word processing and neuroprosthetics. Most BCI applications are still in the research phase and are not yet suitable for widespread everyday use. Current limitations include low information transfer rates, variable reliability, and inconvenience due to electrode maintenance requirements and software handling. There are many proposed countermeasures to mitigate risks, but extensive research is still necessary, due to the significant threats associated with these systems.

}, keywords = {Brain-Computer Interfaces, Cybersecurity, Neuroprivacy, Neurosecurity, privacy}, author = {Stathoulis, John D. and Bakalis, Vissarion I. and Costas Vassilakis} } @article {857, title = {Stitching History into Semantics: LLM-Supported Knowledge Graph Engineering for 19th-Century Greek Bookbinding}, journal = {Machine Learning and Knowledge Extraction}, volume = {7}, year = {2025}, pages = {59}, abstract = {

Preserving cultural heritage can be efficiently supported by structured and semantic representation of historical artifacts. Bookbinding, a critical aspect of book history, provides valuable insights into past craftsmanship, material use, and conservation practices. However, existing bibliographic records often lack the depth needed to analyze bookbinding techniques, provenance, and preservation status. This paper presents a proof-of-concept system that explores how Large Language Models (LLMs) can support knowledge graph engineering within the context of 19th-century Greek bookbinding (1830{\textendash}1900), and as a result, generate a domain-specific ontology and a knowledge graph. Our ontology encapsulates materials, binding techniques, artistic styles, and conservation history, integrating metadata standards like MARC and Dublin Core to ensure interoperability with existing library and archival systems. To validate its effectiveness, we construct a Neo4j knowledge graph, based on the generated ontology and utilize Cypher Queries{\textemdash}including LLM-generated queries{\textemdash}to extract insights about bookbinding practices and trends. This study also explores how semantic reasoning over the knowledge graph can identify historical binding patterns, assess book conservation needs, and infer relationships between bookbinding workshops. Unlike previous bibliographic ontologies, our approach provides a comprehensive, semantically rich representation of bookbinding history, methods and techniques, supporting scholars, conservators, and cultural heritage institutions. By demonstrating how LLMs can assist in ontology/KG creation and query generation, we introduce and evaluate a semi-automated pipeline as a methodological demonstration for studying historical bookbinding, contributing to digital humanities, book conservation, and cultural informatics. Finally, the proposed approach can be used in other domains, thus, being generally applicable in knowledge engineering.

}, keywords = {bookbinding history, Cultural heritage, knowledge graphs, large language models, ontology engineering}, issn = {2504-4990}, doi = {https://doi.org/10.3390/make7030059}, author = {Doumanas, Dimitrios and Ntalouka, Efthalia and Vassilakis, Costas and Wallace, Manolis and Kotis, Konstantinos} } @conference {819, title = {SodaSense: An Intelligence Platform for Micro-Mobility, Micro-Climate and Agriculture}, booktitle = {Proceedings of the GEOProcessing 2023}, year = {2023}, abstract = {

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.

}, keywords = {big data management and analysis, spatial time series, trajectories}, author = {Paraskevi Raftopoulou and Spiros Skiadopoulos and Christos Tryfonopoulos and Costas Vassilakis} } @article {823, title = {A Software Vulnerability Management Framework for the Minimization of System Attack Surface and Risk}, journal = {Electronics}, volume = {12}, year = {2023}, month = {may}, pages = {2278}, abstract = {

Current Internet of Things (IoT) systems comprise multiple software systems that are deployed to provide users with the required functionalities. System architects create system blueprints and draw specifications for the software artefacts that are needed; subsequently, either custom-made software is developed according to these specifications and/or ready-made COTS/open source software may be identified and customized to realize the overall system goals. All deployed software however may entail vulnerabilities, either due to insecure coding practices or owing to misconfigurations and unexpected interactions. Moreover, software artefacts may implement a much broader set of functionalities than may be strictly necessary for the system at hand, in order to serve a wider range of needs, and failure to appropriately configure the deployed software to include only the required modules results in the further increase of the system attack surface and the associated risk. In this paper, we present a software vulnerability management framework which facilitates (a) the configuration of software to include only the necessary features, (b) the execution of security-related tests and the compilation of platform-wide software vulnerability lists, and (c) the prioritization of vulnerability addressing, considering the impact of each vulnerability, the associated technical debt for its remediation, and the available security budget. The proposed framework can be used as an aid in IoT platform implementation by software architects, developers, and security experts.

}, keywords = {IoT systems, risk management, software vulnerabilities, system design, system security, technical debt}, doi = {10.3390/electronics12102278}, url = {https://doi.org/10.3390/electronics12102278}, author = {Panagiotis Sotiropoulos and Christos-Minas Mathas and Costas Vassilakis and Nicholas Kolokotronis} } @inbook {807, title = {Safe Travelling Period Recommendation to High Attack Risk European Destinations Based on Past Attack Information}, booktitle = {Lecture Notes in Social Networks}, year = {2021}, pages = {77{\textendash}100}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

Terrorism is a significant deterrent for tourism. It affects both visitors and local citizens and personnel of a country or area. On one hand, the potential visitor will probably avoid travelling to a high attack risk country, due to safety reasons, hence will miss the opportunity to visit it, and, on the other hand, the country{\textquoteright}s tourism will decline. This work addresses the aforementioned problem by (1) showing that relatively safe visiting periods for high attack risk European countries can be predicted with high accuracy, using limited information, comprising of attack and fatality data from the past years, which are widely available, and (2) developing an algorithm that recommends relatively safe periods to potential travellers. The results of this work will be useful for tourists, visitors, businesses and operators, as well as relevant stakeholders and actors.

}, keywords = {Evaluation, Recommendation algorithm, Risk Calculation, Safety Perception, Safety prediction, Terrorist Attacks, tourism}, doi = {10.1007/978-3-030-67044-3_3}, author = {Dimitris Spiliotopoulos and Dionisis Margaris and Costas Vassilakis} } @article {770, title = {A Semantic Mixed Reality Framework for Shared Cultural Experiences Ecosystems}, journal = {Big Data and Cognitive Computing}, volume = {4}, year = {2020}, month = {4/2020}, pages = {6}, abstract = {This paper presents SemMR, a semantic framework for modelling interactions between human and non-human entities and managing reusable and optimized cultural experiences, towards a shared cultural experience ecosystem that might seamlessly accommodate mixed reality experiences. The SemMR framework synthesizes and integrates interaction data into semantically rich reusable structures and facilitates the interaction between different types of entities in a symbiotic way, within a large, virtual, and fully experiential open world, promoting experience sharing at the user level, as well as data/application interoperability and low-effort implementation at the software engineering level. The proposed semantic framework introduces methods for low-effort implementation and the deployment of open and reusable cultural content, applications, and tools, around the concept of cultural experience as a semantic trajectory or simply, experience as a trajectory (eX-trajectory). The methods facilitate the collection and analysis of data regarding the behaviour of users and their interaction with other users and the environment, towards optimizing eX-trajectories via reconfiguration. The SemMR framework supports the synthesis, enhancement, and recommendation of highly complex reconfigurable eX-trajectories, while using semantically integrated disparate and heterogeneous related data. Overall, this work aims to semantically manage interactions and experiences through the eX-trajectory concept, towards delivering enriched cultural experiences.}, keywords = {cultural experience, intelligent interaction, Mixed Reality, semantics, Usability}, doi = {https://doi.org/10.3390/bdcc4020006}, author = {Costas Vassilakis and Konstantinos Kotis and Dimitris Spiliotopoulos and Dionisis Margaris and Vlasios Kasapakis and Christos-Nikolaos Anagnostopoulos and Georgios Santipantakis and George A. Vouros and Theodore Kotsilieris and Volha Petukhova and Andrei Malchanau and Ioanna Lykourentzou and Kaj Michael Helin and Artem Revenko and Nenad Gligoric and Boris Pokric} } @conference {777, title = {Semantics-Driven Conversational Interfaces for Museum Chatbots}, booktitle = {Proceedings of the 22nd International Conference on Human-Computer Interaction, volume "Culture and Computing"}, year = {2020}, publisher = {Springer International Publishing}, organization = {Springer International Publishing}, abstract = {

This work addresses the challenges of creating usable and personalized conversational interfaces for broad, yet applicable, domains that require user engagement and learning, such as museum chatbots. Whether the chatbots are standalone or coupled with virtual agents or real-life robots, the functional requirements for interaction that targets specific learning aspects would be expected to be more or less similar. This work reports on experimental semantics-driven conversational interface design for chatbots in museum settings, targeting visitors to converse about exhibits and learn information about their style, the artists, the era, and other aspects related to them. Depending on the semantics (presentation, learning, exploration), chatbot scenarios were designed and evaluated by participants in a formative evaluation. The evaluation show that user requirement perception manifests in expectations on the semantic level, instead of just the technical level. The results between the scenarios are compared to see how the semantics considered for the design transferred to the implementation and to the user perception.

}, keywords = {chatbots, conversational interfaces, cultural technology, semantics}, doi = {10.1007/978-3-030-50267-6_20}, author = {Dimitris Spiliotopoulos and Konstantinos Kotis and Costas Vassilakis and Dionisis Margaris} } @conference {726, title = {Scavenger Hunt in the Roads of Freedom (Greek title: {\textquotedblleft}Κυνήγι θησαυρού στους Δρόμους της Ελευθερίας")}, booktitle = {Proceedings of the 3nd Pan-Hellenic Conference on Digital Cultural Heritage-EuroMed 2019}, year = {2019}, abstract = {The project "Kalamata 1821: Roads of freedom" is being funded in the context of the Action "RESEARCH - CREATE - INNOVATE. The project, which encompasses original historic research work in the University of the Peloponnese, is an effort to narrate a historic course of 200 years for the city of Kalamata, from the eruption of the Greek revolution until today, through a modern and fresh perspective. This paper will present one of the digital applications developed within the project, and more specifically the Scavenger Hunt that is being developed by the Knowledge and Uncertainty lab of the Department of Informatics and Telecommunications in Tripolis. The game is designed for mobile devices and its goal is to link the historic content of the project with the contemporary city and, in a gamified fashion, assist the user not only to familiarize with the history of the city but also to navigate in the city and connect with the local market. By searching through pictures of various locations of the city, the visitor is directed to the most outstanding locations of the war of independence, and learns about the contribution of the city of Kalamata in this turning point for the history of the Greek nation. At the same time, the visitor is rewarded by receiving offers for local stores.}, keywords = {Greek War of Independence, Kalamata, Roads of Freedom, Scavenger Hunt}, author = {Manolis Wallace and Vassilis Poulopoulos and George Lepouras and Costas Vassilakis and Angeliki Antoniou} } @proceedings {590, title = {SciTo trends: visualising scientific topic trends}, year = {2019}, month = {September}, author = {Serafeim Chatzopoulos and Panagiotis Deligiannis and Thanasis Vergoulis and Ilias Kanellos and Christos Tryfonopoulos and Theodore Dalamagas} } @conference {Margaris_2019_asonam, title = {Social Relations versus Near Neighbours: Reliable Recommenders in Limited Information Social Network Collaborative Filtering for Online Advertising}, booktitle = {Proceedings of the 2019 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining (ASONAM 2019)}, year = {2019}, month = {aug}, abstract = {Online advertising benefits by recommender systems since the latter analyse reviews and rating of products, providing useful insight of the buyer perception of products and services. When traditional recommender system information is enriched with social network information, more successful recommendations are produced, since more users{\textquoteright} aspects are taken into consid-eration. However, social network information may be unavaila-ble since some users may not have social network accounts or may not consent to their use for recommendations, while rating data may be unavailable due to the cold start phenomenon. In this paper, we propose an algorithm that combines limited col-laborative filtering information, comprised only of users{\textquoteright} ratings on items, with limited social network information, com-prised only of users{\textquoteright} social relations, in order to improve (1) prediction accuracy and (2) prediction coverage in collaborative filtering recommender systems, at the same time. The proposed algorithm considerably improves rating prediction accuracy and coverage, while it can be easily integrated in recommender systems.}, keywords = {collaborative filtering, Evaluation, Limited Information, Near Neighbours, Online Advertising, Pearson Correlation Coefficient, Social Networks}, author = {Dionisis Margaris and Dimitris Spiliotopoulos and Costas Vassilakis} } @conference {727, title = {Supporting small museums through social network semantic analysis (Greek title: Υποστήριξη μικρών μουσείων μέσω της σημασιολογικής ανάλυσης κοινωνικών δικτύων)}, booktitle = {Proceedings of the 3nd Pan-Hellenic Conference on Digital Cultural Heritage-EuroMed 2019}, year = {2019}, abstract = {Greece has a significant historic, archaeological and cultural wealth, and a big number of museums and related venues. Some of them are big, both in size and resources -human as well as financial. Most venues however are small in size, are not connected with larger organizations, have constrained budgets and little or no permanent staff. In this paper, we focus on that particular category of museums. Many of these museums possess noteworthy collections, and it would be desirable if the general public could enjoy them. Unfortunately, in most cases, even the existence of the museums is not generally known, even to inhabitants of the cities at which the museums are located. The small number of visitors leads to confined revenues, and this in turn leads to a situation which is not financially viable. In order for a small museum to survive, its existence and value must be made known to the wide public. However, this is inhibited due to the lack of resources to finance advertising and the lack of specialized personnel. In this paper, we combine our experiences on small museums, which has been developed within the CrossCult H2020 project, with know-how on social network analysis which has been gained in the context of the PaloAnalytics national project, in order to offer viable solutions for promotion, which are tailored to the needs of small museums.}, keywords = {semantic analysis, small-sized museums, Social Networks}, author = {Manolis Wallace and Vassilis Poulopoulos and George Lepouras and Costas Vassilakis and Angeliki Antoniou} } @conference {DBLP:conf/gis/Chatzigeorgakidis18, title = {Scalable hybrid similarity join over geolocated time series}, booktitle = {Proceedings of the 26th ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, SIGSPATIAL 2018, Seattle, WA, USA, November 06-09, 2018}, year = {2018}, pages = {119{\textendash}128}, doi = {10.1145/3274895.3274949}, url = {https://doi.org/10.1145/3274895.3274949}, author = {Georgios Chatzigeorgakidis and Kostas Patroumpas and Dimitrios Skoutas and Spiros Athanasiou and Spiros Skiadopoulos} } @article {vassilakis-snam-2017a, title = {Stimulation of reflection and discussion in museum visits through the use of social media}, journal = {Social Network Analysis and Mining}, volume = {7}, number = {40}, year = {2017}, month = {12}, pages = {1-12}, publisher = {Springer-Verlag GmbH Austria}, abstract = {In this paper, we examine how social media can be linked to cultural heritage and in particular how we can incorporate games, social networks, history reflection and culture. More specifically, we explore the following aspects: (a) how social media sites can be integrated into the museum user experience (b) how user interactions within the social media, both within the context of the museum experience and outside it, can be exploited to enhance the quality of recommendations made to the users, (c) how trending topics from social media can be used to link museum exhibits with today{\textquoteright}s topics of interest and (d) how multi-level related terms extraction from social media data can lead to proposals for reflections to users. The end goal is to provide increased stimuli for users to study exhibits deeper and reflect on them, as well as to trigger discussion between the users, thus maximizing the impact of a museum visit.}, keywords = {big data, cognitive style, Communication, reflection, Social Networks, user profiling}, doi = {10.1007/s13278-017-0460-3}, url = {https://link.springer.com/article/10.1007/s13278-017-0460-3}, author = {Costas Vassilakis and Angela Antoniou and Giorgos Lepouras and Vassilis Poulopoulos and Manolis Wallace and Stavroula Bampatzia and Ioannis Bourlakos} } @proceedings {DBLP:conf/esws/2016, title = {The Semantic Web. Latest Advances and New Domains - 13th International Conference, ESWC 2016, Heraklion, Crete, Greece, May 29 - June 2, 2016, Proceedings}, volume = {9678}, year = {2016}, publisher = {Springer}, isbn = {978-3-319-34128-6}, doi = {10.1007/978-3-319-34129-3}, url = {https://doi.org/10.1007/978-3-319-34129-3}, editor = {Harald Sack and Eva Blomqvist and Mathieu d{\textquoteright}Aquin and Chiara Ghidini and Simone Paolo Ponzetto and Christoph Lange} } @conference {bampatzia-gala2016, title = {Serious games: Valuable Tools for Cultural Heritage}, booktitle = {Proceedings of the 2016 Games and Learning Alliance Conference}, year = {2016}, month = {12}, pages = {331{\textendash}341}, abstract = {Wishing to connect cultural heritage, games and social networks, the present work describes games to be used within the framework of a European H2020 project. For the purposes of supporting the museum visit, before, during and after, 5 games were designed for social networks to accomplish user profil-ing, to promote the museum and the application through social network dissemi-nation, to introduce museum items and themes and to also function as visit sou-venirs. The games are also presented in a generic framework for games in cultural heritage, which has been used successfully in the past.}, doi = {https://doi.org/10.1007/978-3-319-50182-6_30}, url = {https://link.springer.com/chapter/10.1007/978-3-319-50182-6_30}, author = {Stavroula Bampatzia and Ioannis Bourlakos and Angela Antoniou and Costas Vassilakis and Giorgos Lepouras and Manolis Wallace} } @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/icdm/PoulisSLG13, title = {Select-Organize-Anonymize: A Framework for Trajectory Data Anonymization}, booktitle = {13th IEEE International Conference on Data Mining Workshops, ICDM Workshops, TX, USA, December 7-10, 2013}, year = {2013}, pages = {867{\textendash}874}, doi = {10.1109/ICDMW.2013.136}, url = {https://doi.org/10.1109/ICDMW.2013.136}, author = {Giorgos Poulis and Spiros Skiadopoulos and Grigorios Loukides and Aris Gkoulalas-Divanis} } @mastersthesis {526, title = {A Software Development Methodology and a Software Architecture for Context-Aware M-Commerce Applications}, volume = {Ph.D. thesis}, year = {2012}, month = {02/2012}, pages = {369}, school = {University of the Peloponnese}, type = {Doctoral}, address = {Tripolis}, abstract = {

Mobile commerce is gaining importance in the recent years, as an enhanced version of e-commerce for the moving user. The mobile services through which m-commerce takes place operate in highly dynamic environments with diverse characteristics and under varying conditions. The characteristics and conditions of these environments {\textendash}called context{\textendash} can be exploited in order to offer a suitable user experience and deliver innovative and enhanced mobile services that will facilitate user interaction, attract new customers and maintain existing ones. Therefore, mobile commerce applications adhering to {\textquotedblleft}anytime and anywhere{\textquotedblright} paradigm are required to be flexible. They should be able to adapt their user-perceived constituent parts, i.e. their interface, services and content towards a certain context. Several proposals for definition of context have been already proposed originating from various areas related to mobile commerce. However, an integrated, formal and methodological approach for the determination and representation of context, adjusted to special characteristics of mobile commerce applications, has not been insofar presented. This is one challenge we address in this thesis, through a conceptual model that includes: i) a clear and formal definition of context, ii) the depiction of its specific characteristics as metadata, iii) a methodology for its determination and iv) the presentation of an extension of UML class and case diagrams for its representation, all of them tailored to the special nature of mobile commerce applications.

Once the context information for an m-commerce application has been determined, the next step in order to achieve the goal of adaptivity is to capture the context information from its sources, process and distribute it to the software components that will use it. In order to offer a complete suite of tools for context management, we propose a software architecture for context information management suitable for m-commerce applications. We describe the functionality and characteristics of its components, as well as the interaction among these different components.

The usage of context information in order to achieve the ultimate goal of adaptivity should be done from a subsystem designed in such way that will simplify and homogenize the relevant processes and at the same time promote the independence of the code of the main application from the adaptation code. Addressing this issue, in this thesis we propose an approach for developing adaptive mobile commerce applications, adhering to the separation of concerns principle, which is offered by the aspect-oriented paradigm. By clearly separating the work required for the development of the application logic from that required for enabling application{\textquoteright}s adaptive behavior, this approach reduces the development effort and at the same time promotes the flexibility, manageability and maintainability of adaptive m-commerce applications. }, keywords = {Context Information, context management, context-awareness, mobile commerce, Mobile Commerce Applications, Software Adaptation, Software Architecture for M-commerce Applications, Software Methodology for M-commerce Applications}, url = {https://soda.dit.uop.gr/sites/soda.dit.uop.gr/files//Benou_PhDThesis.pdf}, author = {Poulcheria Benou}, editor = {Costas Vassilakis} } @conference {benou2011a, title = {A Software Architecture for Provision of Context-Aware Web-based m-Commerce Applications}, booktitle = {Proceedings of the 11th IEEE International Conference on Computer and Information Technology (CIT 2011)}, year = {2011}, month = {8}, publisher = {IEEE Computer Society}, organization = {IEEE Computer Society}, abstract = {Mobile commerce is gaining significant importance in the recent years as an alternative option of e-commerce for the moving user. The mobile applications through which mcommerce takes place operate in highly dynamic environments with diverse characteristics and under varying conditions. The characteristics and conditions of these environments {\textendash}called context{\textendash} should be exploited in order to provide adaptive services; services that offer a suitable user experience and deliver innovative and enhanced capabilities that will facilitate user interaction, attract new customers and maintain existing ones. The goal of adaptivity is realized through the adaptation of user interface, functionality and content of applications using the context information. Therefore, context-awareness constitutes an essential aspect {\textendash} almost a requirement {\textendash} of mobile services. In order to realize context-aware services, there is a necessity to capture the context information from its sources, process and distribute it to the software components that will use it. In this paper, we propose a software architecture for context information management suitable for m-commerce applications. We describe the functionality and characteristics of its components, as well as the interaction among these different components}, doi = {10.1109/CIT.2011.20}, author = {Poulcheria Benou and Costas Vassilakis} } @conference {Akim2011a, title = {Spreading Activation for Web Scale Reasoning: Promise and Problems}, booktitle = {WebSci 11, poster presentation}, year = {2011}, month = {6}, pages = {1-4}, abstract = {Various forms of spreading activation has been used in a number of web systems, not least in the PageRank algorithm. In our own work we have been using this as a technique for managing context over small and large ontologies, and both our own work and that in LarKC suggests that spreading activation has the potential to aid in reasoning over web-scale data sets including the growing set of linked open data resources. Of particular importance is that spreading activation can be applied locally to a dynamic selfselecting working set of an (practically) unbound linked data collection, as well as globally to the entire collection. However, this potential does not come without problems, some concerning the nature of the algorithm on any large data set, and some more to do with the particular nature of linked open data.}, author = {Nazihah Md. Akim and Alan Dix and Akrivi Katifori and Giorgos Lepouras and Nadeem Shabir and Costas Vassilakis} } @conference {wallace11a, title = {Supporting User Roles in Ontology Fuzzification}, booktitle = {Proceedings of the 6th International Workshop on Semantic media adaptation and personalization (SMAP)}, year = {2011}, month = {dec}, publisher = {IEEE Computer Society}, organization = {IEEE Computer Society}, abstract = {Manual ontology development is clearly a strenuous task. Whilst a variety of ontological engineering methodologies exist, their actual application is far from trivial, mainly due to the widely diverse nature of the tasks involved. In this work we study these tasks and identify the different types of human experts that are best suited to perform each one. As a result, we present a cooperative version of an ontological engineering methodology, together with a graphical tool that supports it.}, keywords = {domain expert, fuzzification, knowledge engineer, ontology development, user roles}, doi = {10.1109/smap.2011.24}, url = {https://www.computer.org/csdl/proceedings/smap/2011/4524/00/4524a057.pdf}, author = {Manolis Wallace and Panos Alexopoulos and Ioannis Papafragkos and Costas Vassilakis} } @article {dix2010, title = {Spreading Activation Over Ontologies: From Personal Context To Web Scale Reasoning}, journal = {International Journal of Semantic Computing}, volume = {Special issue on Web Scale Reasoning}, year = {2010}, pages = {59{\textendash}102}, abstract = {This paper describes methods to allow spreading activation to be used on web-scale information resources. Existing work has shown that spreading activation can be used to model context over small personal ontologies, which can be used to assist in various user activities, for example, in autocompleting web forms. This previous work is extended and methods are developed by which large external repositories, including corporate information and the web, can be linked to the user?s personal ontology and thus allow automated assistance that is able to draw on the entire web of data. The basic idea is augment the personal ontology with cached data from external repositories, where the choice of what data to fetch or discard is related to the level of activation of entities already in the personal ontology or cached data. This relies on the assumption that the working set of highly active entities is relatively small; empirical results are presented, which suggest these assumptions are likely to hold. Implications of the techniques are discussed for user interaction and for the social web. In addition, warm world reasoning is proposed, applying rule-based reasoning over activate entities, potentially merging symbolic and sub-symbolic reasoning over web-scale knowledge bases.}, doi = {10.1142/S1793351X10000973}, author = {Alan Dix and Akrivi Katifori and Giorgos Lepouras and Costas Vassilakis and Nadeem Shabir} } @proceedings {DBLP:conf/ssdbm/2009, title = {Scientific and Statistical Database Management, 21st International Conference, SSDBM 2009, New Orleans, LA, USA, June 2-4, 2009, Proceedings}, volume = {5566}, year = {2009}, publisher = {Springer}, isbn = {978-3-642-02278-4}, doi = {10.1007/978-3-642-02279-1}, url = {https://doi.org/10.1007/978-3-642-02279-1}, editor = {Marianne Winslett} } @article {DBLP:journals/tkde/KantereSS09, title = {Storing and Indexing Spatial Data in P2P Systems}, journal = {IEEE Trans. Knowl. Data Eng.}, volume = {21}, number = {2}, year = {2009}, pages = {287{\textendash}300}, doi = {10.1109/TKDE.2008.139}, url = {https://doi.org/10.1109/TKDE.2008.139}, author = {Verena Kantere and Spiros Skiadopoulos and Timos K. Sellis} } @conference {Katifori2008133, title = {Selected results of a comparative study of four ontology visualization methods for information retrieval tasks}, booktitle = {Proceedings of the 2nd International Conference on Research Challenges in Information Science, RCIS 2008}, year = {2008}, note = {cited By (since 1996) 0}, month = {6}, pages = {133-140}, abstract = {The need for effective ontology visualization for design, management and browsing has arisen as a result of the progress in the areas of Semantic Web and Personal Information Management. There are several ontology visualizations available through existing ontology management tools, but not as many evaluations to determine their advantages and disadvantages and their suitability for various ontologies and user groups. This work presents selected results of an evaluation of four visualization methods in ProtΓ{\textcopyright}gΓ{\textcopyright}.}, keywords = {Communication, Comparative studies, Information management, Information retrieval, Information science, Information services, Information theory, Management, Management information systems, Ontology, Ontology managements, Personal Information managements, Semantic Web, Telecommunication services, User groups, User interfaces, Visualization, visualization methods}, doi = {10.1109/RCIS.2008.4632101}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-57349172797\&partnerID=40\&md5=1f36a9a0febecb929cd7904c84004143}, author = {Akrivi Katifori and Elena Torou and Costas Vassilakis and Giorgos Lepouras and C. Halatsis} } @conference {Katifori200832, title = {Supporting research in historical archives: Historical information visualization and modeling requirements}, booktitle = {Proceedings of the International Conference on Information Visualisation}, year = {2008}, note = {cited By (since 1996) 0}, month = {7}, pages = {32-37}, abstract = {The on-going progress in the area of digital libraries has lead to the beginning of a digitization effort in Historical Archives, as well. The requirements of historical research, which works with histories of entities and incomplete information, create the need for supplementary tools to support users in handling the digitized content. This work is based on a user study of historian information retrieval methods in order to create a set of tools for the context of historical archives, which will facilitate historical data storage, management and visualization. Β{\textcopyright} 2008 IEEE.}, keywords = {Data visualization, Digital libraries, Heuristics, Historical archive, Information analysis, Information management, Information retrieval, Information science, Information services, Information systems, International conferences, Libraries, Ontology, Search engines, Visualization}, doi = {10.1109/IV.2008.70}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-51749114860\&partnerID=40\&md5=a5b3e7f74314d5651816424c11e6cbc1}, author = {Akrivi Katifori and Elena Torou and Costas Vassilakis and C. Halatsis} } @conference {DBLP:conf/icde/PolyzotisSVSF07, title = {Supporting Streaming Updates in an Active Data Warehouse}, booktitle = {Proceedings of the 23rd International Conference on Data Engineering, ICDE 2007, The Marmara Hotel, Istanbul, Turkey, April 15-20, 2007}, year = {2007}, pages = {476{\textendash}485}, doi = {10.1109/ICDE.2007.367893}, url = {https://doi.org/10.1109/ICDE.2007.367893}, author = {Neoklis Polyzotis and Spiros Skiadopoulos and Panos Vassiliadis and Alkis Simitsis and Nils-Erik Frantzell} } @conference {598, title = {Semantic Similarity Methods in WordNet and their Application to Information Retrieval on the Web}, booktitle = {Proceedings of 7th ACM International Workshop on Web Information and Data Management (WIDM)}, year = {2005}, month = {November}, publisher = {ACM}, organization = {ACM}, address = {Bremen, Germany}, abstract = {Semantic Similarity relates to computing the similarity be- tween concepts which are not lexicographically similar. We investigate approaches to computing semantic similarity by mapping terms (concepts) to an ontology and by examining their relationships in that ontology. Some of the most popular semantic similarity methods are implemented and evaluated using WordNet as the underlying reference ontology. Building upon the idea of semantic similarity, a novel information retrieval method is also proposed. This method is capable of detecting similarities between documents containing semantically similar but not necessarily lexicographically similar terms. The proposed method has been evaluated in retrieval of images and documents on the Web. The experimental results demonstrated very promising performance improvements over state-of-the-art information retrieval methods.}, keywords = {Information retrieval, Semantic Similarity, WordNet, World Wide Web}, author = {Giannis Varelas and Epimenides Voutsakis and Paraskevi Raftopoulou and E.G.M. Petrakis and Evangelos Milios} } @conference {Vassilakis2005421, title = {A semantics-based consultations workbench}, booktitle = {ITI 3rd International Conference on Information and Communications Technology, ICICT 2005 - Enabling Technologies for the New Knowledge Society}, volume = {2005}, year = {2005}, note = {cited By (since 1996) 0}, month = {12}, pages = {421-434}, abstract = {Econsultations constitute an effective means to inclusive and informed participation of citizens and society in policy, decision and law formulation processes, and an answer to democratic deficit issues. Econsultation platforms need to support all stages of consultation processes including agenda setting and topics raising, legislation proposal publicity, notification of developments, proposal debate and commentary, collection, analysis and synthesis of views. In this paper we present the design of an open platform assisting policy makers and the civil society in the set-up, enactment, management and federation of inclusive and informed digital consultations. The proposed platform employs semantic techniques, such as semantics, content annotation and summarization to support the consultation processes and provide targeted and digested information to participants, and facilitates tailoring of Econsultation procedures by offering basic Econsultation activities as building blocks, which can be combined according to contextual needs. The platform also enables distinct Econsultation processes to be federated, allowing the exchange of information, which may be subject to different semantic annotations and classifications, according to the rules of each Econsultation process.}, keywords = {Classification (of information), Content annotation, Data transfer, Decision making, Econsultations, Knowledge based systems, Logic programming, Platform architecture, Public policy, Semantic technologies, semantics}, doi = {10.1109/ITICT.2005.1609641}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-33847729948\&partnerID=40\&md5=54c7a246c0ee9ae483889741a327253b}, author = {Costas Vassilakis and D. Gouscos and P. Georgiadis} } @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} } @article {Lepouras2003248, title = {A system to support dissemination of knowledge and sharing of experiences in the working environment: Review Code 066}, journal = {International Journal of Continuing Engineering Education and Lifelong Learning}, volume = {13}, number = {3/4}, year = {2003}, pages = {248-257}, publisher = {Inderscience Publishers}, abstract = {In the information era, enterprises strive to be productive and efficient. One feature of this goal is for employers to engage their employees in education programs, to help them to gain new experiences and knowledge and to adapt to an ever-changing working environment. Such programs must be carefully designed in order to achieve satisfactory results. Recently, enterprises, recognising the role that technology can play in the education of their employees, have adopted systems that supplement the traditional educational model with mechanisms that enable the sharing of experiences and knowledge. In this paper we describe an architecture and a system prototype that allows users to search easily for information, interact with colleagues and share experiences, and to compose and disseminate best practices and knowledge. The design of this system is based on insights gained from the operation of the Greek taxation system.}, keywords = {Education computing, Engineering education, Information dissemination, Integrated systems, Knowledge based systems, Systems analysis}, doi = {10.1504/ijceell.2003.003277}, url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-0041975974\&partnerID=40\&md5=3fdaf5e728f5571c01c70507e0ad7004}, author = {Giorgos Lepouras and Costas Vassilakis and G.R.S. Weir} } @conference {649749, title = {Serving Enhanced Hypermedia Information}, booktitle = {Proceedings of the 24th BCS-IRSG European Colloquium on IR Research}, year = {2002}, month = {3}, pages = {86{\textendash}92}, publisher = {Springer-Verlag}, organization = {Springer-Verlag}, address = {London, UK}, abstract = {An apparent limitation of existing Web pages is their inability to accommodate differences in the interests and needs of individual users. The present paper describes an approach that dynamically customises the content of public Web-based information via an interceding {\textquoteright}enhancement server{\textquoteright}. The design and operation of this system is described with examples drawn from two current versions. Indications from early trials support the view that this approach affords considerable scope for accommodating the needs and interests of individual Web users.}, isbn = {3-540-43343-0}, doi = {10.1007/3-540-45886-7_6}, author = {Giorgos Lepouras and Costas Vassilakis and G.R.S. Weir} } @conference {lep2002a1, title = {SMARTGOV: A Governmental Knowledge-based Platform for Public Sector Online Services}, booktitle = {Proceedings KMGov2002}, year = {2002}, month = {5}, pages = {173{\textendash}185}, address = {Copenhagen, Denmark}, abstract = {Public transaction services (such as e-forms), although perceived the future of e-government have not yet realised their full potential. E-forms have a significant role in e-government, as they are the basis for realising most of the twenty public services that all European Union member states have to provide to their citizens and businesses. The aim of this paper is to present a knowledge-based platform to assist public sector employees to generate online transaction services by simplifying their development, maintenance and integration with already installed IT systems.}, author = {E. Tambouris and G. Boukis and Costas Vassilakis and Giorgos Lepouras and S. Rouvas and Canadas, R. and Heredia, S. and Lopez Usero, J. C.} } @conference {Georgiadis_2002, title = {SmartGov: A Knowledge-Based Platform for Transactional Electronic Services}, booktitle = {Lecture Notes in Computer Science}, year = {2002}, month = {9}, pages = {362-369}, publisher = {Springer Berlin Heidelberg}, organization = {Springer Berlin Heidelberg}, abstract = {Public transaction services (such as e-forms) although perceived the future of e-government have not yet realised their full potential. E-forms have a significant role in e-government, as they are the basis for implementing most of the twenty public services that all member states have to provide to their citizens and businesses. The aim of the SmartGov project is to specify, develop, deploy and evaluate a knowledge-based platform to assist public sector employees to generate online transaction services by simplifying their development, maintenance and integration with already installed IT systems. This platform will be evaluated in two European countries (in one Ministry and one Local Authority). This paper outlines key issues in the development of the SmartGov system platform.}, doi = {10.1007/978-3-540-46138-8_59}, url = {https://link.springer.com/chapter/10.1007/978-3-540-46138-8_59}, author = {P. Georgiadis and Giorgos Lepouras and Costas Vassilakis and G. Boukis and E. Tambouris and S. Gorilas and E. Davenport and A. Macintosh and J. Fraser and D. Lochhead} } @conference {vassil99a, title = {Is Server-Side Programming Killing Your Web Server?}, booktitle = {Proceedings of the ActiveWeb 99 Conference}, year = {1999}, month = {10}, address = {Staffordshire University}, abstract = {The paper addresses issues related to client/server technologies and specifically the effectiveness of server-side programming techniques. The motive for this study was the need to create a lightweight and dynamic navigational aid for use in a web site. Towards this goal a number of possible solutions were considered and for two of them an experiment was run to determine the best suited for our case. The rest of the paper outlines our findings.}, url = {http://www.visualize-uk.com/conf/activeweb/proceed/pap7/}, author = {Costas Vassilakis and Giorgos Lepouras} } @proceedings {DBLP:conf/stdbm/1999, title = {Spatio-Temporal Database Management, International Workshop STDBM{\textquoteright}99, Edinburgh, Scotland, September 10-11, 1999, Proceedings}, volume = {1678}, year = {1999}, publisher = {Springer}, isbn = {3-540-66401-7}, doi = {10.1007/3-540-48344-6}, url = {https://doi.org/10.1007/3-540-48344-6}, editor = {Michael H. B{\"o}hlen and Christian S. Jensen and Michel Scholl} }