@article {820,
	title = {Rating Prediction Quality Enhancement in Low-Density Collaborative Filtering Datasets},
	journal = {Big Data and Cognitive Computing},
	volume = {7},
	year = {2023},
	month = {mar},
	pages = {59},
	abstract = {<p>Collaborative filtering has proved to be one of the most popular and successful rating prediction techniques over the last few years. In collaborative filtering, each rating prediction, concerning a product or a service, is based on the rating values that users that are considered {\textquotedblleft}close{\textquotedblright} to the user for whom the prediction is being generated have given to the same product or service. In general, {\textquotedblleft}close{\textquotedblright} users for some user u correspond to users that have rated items similarly to u and these users are termed as {\textquotedblleft}near neighbors{\textquotedblright}. As a result, the more reliable these near neighbors are, the more successful predictions the collaborative filtering system will compute and ultimately, the more successful recommendations the recommender system will generate. However, when the dataset{\textquoteright}s density is relatively low, it is hard to find reliable near neighbors and hence many predictions fail, resulting in low recommender system reliability. In this work, we present a method that enhances rating prediction quality in low-density collaborative filtering datasets, by considering predictions whose features are associated with high prediction accuracy as additional ratings. The presented method{\textquoteright}s efficacy and applicability are substantiated through an extensive multi-parameter evaluation process, using widely acceptable low-density collaborative filtering datasets.</p>
},
	keywords = {collaborative filtering, Evaluation, low density datasets, personalization, rating prediction quality, Recommender Systems, reliability},
	doi = {10.3390/bdcc7020059},
	url = {https://www.mdpi.com/2504-2289/7/2/59},
	author = {Dionisis Margaris and Costas Vassilakis and Dimitris Spiliotopoulos and Stefanos Ougiaroglou}
}
@conference {821,
	title = {RoG: A Pipeline for Automated Sensitive Data Identification and Anonymisation},
	booktitle = {Proceedings of the 2023 IEEE CSR Workshop on Data Science for Cyber Security (DS4CS)},
	year = {2023},
	abstract = {<p>Nowadays, the amount of data available online is constantly increasing. This data may contain sensitive or private information that can expose the person behind the data or be misused by malicious actors for identity theft, stalking, and other nefarious purposes. There is thus, a growing need to protect individuals{\textquoteright} privacy and prevent data breaches in several application domains. Protecting data privacy though, is a complex and multifaceted issue that involves a range of legal, ethical, and technical considerations. In this paper, we discuss the challenges associated with data protection, the role of automated tools, and the effectiveness of identifying and anonymising sensitive data. We then, propose a fully-automated process for sensitive data identification and anonymisation, based on Natural Language Processing (NLP) techniques, that can be applied both in big diverse datasets and to a wide range of domains.</p>
},
	keywords = {anonymisation, automated process, k-anonymity, NER, NLP, pipeline, sensitive/private data},
	author = {Sotiris Nikoletos and Stefanos Vlachos and Efstathios Zaragkas and Costas Vassilakis and Christos Tryfonopoulos and Paraskevi Raftopoulou}
}
@article {Margaris_2016,
	title = {Recommendation information diffusion in social networks considering user influence and semantics},
	journal = {Social Network Analysis and Mining},
	volume = {6},
	number = {1},
	year = {2016},
	month = {nov},
	pages = {108},
	publisher = {Springer Nature},
	abstract = {One of the major problems in the domain of social networks is the handling and diffusion of the vast, dynamic and disparate information created by its users. In this context, the information contributed by users can be exploited to generate recommendations for other users. Relevant recommender systems take into account static data from users{\textquoteright} profiles, such as location, age or gender, complemented with dynamic aspects stemming from the user behavior and/or social network state such as user preferences, items{\textquoteright} general acceptance and influence from social friends. In this paper, we enhance recommendation algorithms used in social networks by taking into account qualitative aspects of the recommended items, such as price and reliability, the influencing factors between social network users, the social network user behavior regarding their purchases in different item categories and the semantic categorization of the products to be recommended. The inclusion of these aspects leads to more accurate recommendations and diffusion of better user-targeted information. This allows for better exploitation of the limited recommendation space, and therefore online advertisement efficiency is raised.},
	keywords = {Collaborative filtering, Information diffusion, Quality of service, Semantic Information, Social Networks},
	doi = {10.1007/s13278-016-0416-z},
	url = {http://rdcu.be/mZ7e},
	author = {Dionisis Margaris and Costas Vassilakis and P. Georgiadis}
}
@conference {margaris15c,
	title = {On Replacement Service Selection in WS-BPEL Scenario Adaptation},
	booktitle = {Proceedings of the 8th IEEE International Conference on Service Oriented Computing \& Applications (SOCA 2015)},
	year = {2015},
	month = {9},
	publisher = {IEEE},
	organization = {IEEE},
	abstract = {WS-BPEL scenario execution adaptation has been proposed by numerous researchers as a response to the need of users to tailor the WS-BPEL scenario execution to their individual preferences; these preferences are typically expressed through Quality of Service (QoS) policies, which the adaptation mechanism considers in order to select the services that will ultimately be invoked to realize the desired business process. In this paper, we consider a number of issues related to WS-BPEL scenario adaptation, aiming to enhance adaptation quality and improve the QoS offered to end users. More specifically, with the goal of broadening the service selection pool we (a) discuss the identification of potential services that can be used to realize a functionality used in the WS-BPEL scenario and (b) elaborate on transactional semantics that invocations to multiple services offered by the same provider may bear. We also describe and validate an architecture for realizing the proposed enhancements.},
	doi = {10.1109/SOCA.2015.11},
	author = {Dionisis Margaris and P. Georgiadis and Costas Vassilakis}
}
@conference {Vasiliadis200924,
	title = {Routing and performance evaluation of dual priority Delta networks under hotspot environment},
	booktitle = {Proceedings - 2009 1st International Conference on Advances in Future Internet, AFIN 2009},
	year = {2009},
	note = {cited By (since 1996) 0},
	month = {6},
	pages = {24-30},
	abstract = {Large swings in the demand for content are commonplace within the Internet. Although Multistage Interconnection Networks (MINs) are fairly flexible in handling varieties of traffic loads, their performance considerably degrades by hotspot traffic, especially at increasing size networks. As alleviation to the tree saturation problem, the prioritizing of packets is proposed leading to a scheme that natively supports multi priority traffic. In this paper the performance evaluation of double-buffered Delta Networks under single hotspot setups, with different offered loads, and 2-class routing traffic is presented and analyzed using simulation experiments. Performance comparison of dual vs. single priority scheme is outlined under hotspot environment, by calculating a universal performance factor, which effectively includes the importance aspect of each of the two most important performance metrics, namely packet throughput and delay. The findings of this paper can be used by MIN designers to optimally configure their networks. Β{\textcopyright} 2009 IEEE.},
	keywords = {Computer simulation, Delta networks, Hot spot, Hotspot traffic, Interconnection networks, Internet, Multistage interconnection network, Multistage interconnection networks, Packet throughput, Performance comparison, Performance evaluation, Performance factors, Performance metrics, Priority schemes, Routing traffic, Saturation problems, Simulation, Simulation experiments, Traffic loads},
	doi = {10.1109/AFIN.2009.12},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-70350757772\&partnerID=40\&md5=f661e197254166cf6cf723546a5e5b88},
	author = {D.C. Vasiliadis and G.E. Rizos and Costas Vassilakis}
}
@conference {Vasiliadis200856,
	title = {Routing and performance analysis of double-buffered omega networks supporting multi-class priority traffic},
	booktitle = {Proc. - The 3rd Int. Conf. Systems and Networks Communications, ICSNC 2008 - Includes I-CENTRIC 2008: Int. Conf. Advances in Human-Oriented and Personalized Mechanisms, Technologies, and Services},
	year = {2008},
	note = {cited By (since 1996) 1},
	month = {10},
	pages = {56-63},
	abstract = {In this paper the modeling of Omega Networks supporting multi-class routing traffic is presented and their performance is analyzed. We compare the performance of multi-class priority mechanism against the single priority one, by gathering metrics for the two most important network performance factors, namely packet throughput and delay under uniform traffic conditions and various offered loads, using simulations. Moreover, two different test-bed setups were used in order to investigate and analyze the performance of all priority-class traffic, under different Quality of Service (QoS) configurations. In the considered environment, Switching Elements (SEs) that natively support multi-class priority routing traffic are used for constructing the MIN, while we also consider double-buffered SEs, two configuration parameters that have not been addressed insofar. The rationale behind introducing a multiple-priority scheme is to provide different QoS guarantees to traffic from different applications, which is a highly desired feature for many IP network operators, and particularly for enterprise networks. Β{\textcopyright} 2008 IEEE.},
	keywords = {Computer networks, Configuration parameters, Enterprise networks, Ip networks, Metropolitan area networks, Network performances, Packet throughputs, Performance analyses, Priority schemes, Qos guarantees, Quality of service, Routing traffics, Set-ups, Systems engineering, Uniform traffics},
	doi = {10.1109/ICSNC.2008.10},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-58149096344\&partnerID=40\&md5=11b2d45a47554d3556034866c2f3ac49},
	author = {D.C. Vasiliadis and G.E. Rizos and Costas Vassilakis and E. Glavas}
}
@conference {Vasiliadis2007937,
	title = {The role of priority mechanisms on performance metrics of double-buffered switching elements},
	booktitle = {AIP Conference Proceedings - ICCMSE 2007},
	volume = {963},
	number = {2},
	year = {2007},
	note = {cited By (since 1996) 0},
	month = {9},
	pages = {937-942},
	abstract = {The main concerns in designing the multistage switching fabrics are speed, throughput, delay and variance of delay for a given bandwidth. The rationale behind using various priority mechanisms is either to offer different quality of service levels to packets or to optimize performance parameters of the network, e.g. minimize internal blocking in the Switching Elements (SEs). We investigated the performance parameters of an enhanced priority (EP) mechanism versus a single priority (SP) one. In the EP scheme, packet priority was computed dynamically and was directly proportional to the transmission queue length of the SE that the packet is currently stored in. Finally, we extended the idea of the priority scheme by proposing a multi-priority (MP) mechanism. In the MP scheme, each SE has two transmission queues per link, with one queue dedicated to high priority packets and the other dedicated to low priority ones. We simulated a multistage network under the uniform traffic condition and concluded that the proposed double-buffered SEs provide higher throughput, and decreased latency. Β{\textcopyright} 2007 American Institute of Physics.},
	doi = {10.1063/1.2836247},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-71449122900\&partnerID=40\&md5=3cde25f68a16c221bd7e6ac466752465},
	author = {D.C. Vasiliadis and G.E. Rizos and Costas Vassilakis}
}
@conference {DBLP:conf/icsoft/VassilakisLK06,
	title = {Reverse engineering electronic services: from e-forms to knowledge},
	booktitle = {ICSOFT (1)},
	year = {2006},
	month = {9},
	pages = {273-278},
	abstract = {On their route to e-governance, public administrations have developed e-services. Each e-service encompasses a significant amount of knowledge in the form of examples, help texts, legislation excerpts, validation checks etc. This knowledge has been offered by domain experts in the phases of service analysis, design and implementation, being however bundled within the software, it cannot be readily retrieved and used in other organizational processes, including the development of new services. In this paper, we present an approach for reverse engineering e-services, in order to formulate knowledge items of a high level of abstraction, which can be made available to the employees of the organizations. Moreover, the knowledge items formulated in the reverse engineering process are stored into a knowledge-based e-service development platform, making them readily available for use in the development of other services.},
	author = {Costas Vassilakis and Giorgos Lepouras and Akrivi Katifori}
}
@article {1009361,
	title = {Real exhibitions in a virtual museum},
	journal = {Virtual Reality},
	volume = {7},
	number = {2},
	year = {2004},
	pages = {120{\textendash}128},
	publisher = {Springer-Verlag},
	address = {London, UK},
	abstract = {When creating a virtual environment open to the public a number of challenges have to be addressed. The equipment has to be chosen carefully in order to be be able to withstand hard every-day usage, the application has not only to be robust and easy to use, but has also to be appealing to the user, etc. The current paper presents findings gathered from the creation of a multi-thematic virtual museum environment to be offered to visitors of real world museums. A number of design and implementation aspects are described along with an experiment designed to evaluate alternative approaches for implementing the navigation in a virtual museum environment. The paper is concluded with insights gained from the development of the Virtual Museum and portrays future research plans.},
	issn = {1359-4338},
	doi = {10.1007/s10055-004-0121-5},
	url = {https://link.springer.com/article/10.1007/s10055-004-0121-5},
	author = {Giorgos Lepouras and Akrivi Katifori and Costas Vassilakis and D. Charitos}
}
@conference {Lep2004d,
	title = {Reusability in Electronic Services Development},
	booktitle = {Proceedings of the CSITeA 04 conference},
	year = {2004},
	month = {12},
	abstract = {Electronic government employs electronic services to facilitate interaction with citizens and enterprises and deliver a rich and high quality spectrum of services. Development of electronic services can be greatly assisted, both in terms of development cost and roll-out time, by exploiting the reusability inherent in them. Reusability may be promoted by identifying reusable objects in the context of electronic service development, building and populating a repository with such components and providing the means for developers to locate, extract and adapt them to suit the task at hand. In this paper we analyse electronic services to recognise reusable components and present means and techniques that empower electronic service developers to build electronic services through reusable components.},
	author = {Costas Vassilakis and Giorgos Lepouras}
}
