Kerkyra, Greece
Kerkyra, Greece

The Ionian University is a university located in the city of Corfu, Greece. It was established in 1984 by the Greek government under the Prime Ministership of Andreas Papandreou, in recognition of Corfu's contribution to education in Greece as the seat of the first University of Greece, the Ionian Academy, that was established in 1824, forty years before the cession of the Ionian islands to Greece and just three years after Greece's Revolution of 1821. Andreas Papandreou thus kept an election promise to the people of Corfu, satisfying their long held demand that a successor university to the Ionian Academy be built. On 21 May 1985, the founding of the Ionian University was announced in a speech at City-Hall square in Corfu city. The Ionian University was created pursuant to presidential order 8320-3-84, along with the Aegean University and the University of Thessaly. The university opened its doors to students in 1985. Wikipedia.

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Kapidakis S.,Ionian University
MATEC Web of Conferences | Year: 2016

Computer services are normally assumed to work well all the time. This usually happens for crucial services like bank electronic services, but not necessarily so for others, that there is no commercial interest in their operation. In this work we examined the operation and the errors of information services and tried to find clues that will help predicting the consistency of the behavior and the quality of the harvesting, which is harder because of the transient conditions and the many services and the huge amount of harvested information. We found many unexpected situations. The services that always successfully satisfy a request may in fact return part of it. A significant part of the OAI services have ceased working while many other serves occasionally fail to respond. Some services fail in the same way each time, and we pronounce them dead, as we do not see a way to overcome that. Others also always, or sometimes fail, but not in the same way, and we hope that their behavior is affected by temporary factors, that may improve later on. We categorized the services into classes, to study their behavior in more detail. © 2016 The Authors, published by EDP Sciences.

Oikonomou K.,Ionian University | Stavrakakis I.,National and Kapodistrian University of Athens
IEEE Journal on Selected Areas in Communications | Year: 2010

Service placement is a key problem in communication networks as it determines how efficiently the user service demands are supported. This problem has been traditionally approached through the formulation and resolution of large optimization problems requiring global knowledge and a continuous recalculation of the solution in case of network changes. Such approaches are not suitable for large-scale and dynamic network environments. In this paper, the problem of determining the optimal location of a service facility is revisited and addressed in a way that is both scalable and deals inherently with network dynamicity. In particular, service migration which enables service facilities to move between neighbor nodes towards more communication cost-effective positions, is based on local information. The migration policies proposed in this work are analytically shown to be capable of moving a service facility between neighbor nodes in a way that the cost of service provision is reduced and - under certain conditions - the service facility reaches the optimal (cost minimizing) location, and locks in there as long as the environment does not change; as network conditions change, the migration process is automatically resumed, thus, naturally responding to network dynamicity under certain conditions. The analytical findings of this work are also supported by simulation results that shed some additional light on the behavior and effectiveness of the proposed policies. © 2010 IEEE.

Poulos M.,Ionian University
PLoS ONE | Year: 2016

The problem of controlling stationarity involves an important aspect of forecasting, in which a time series is analyzed in terms of levels or differences. In the literature, non-parametric stationary tests, such as the Kwiatkowski-Phillips-Schmidt-Shin (KPSS) tests, have been shown to be very important; however, they are affected by problems with the reliability of lag and sample size selection. To date, no theoretical criterion has been proposed for the lag-length selection for tests of the null hypothesis of stationarity. Their use should be avoided, even for the purpose of so-called 'confirmation'. The aim of this study is to introduce a new method that measures the distance by obtaining each numerical series from its own time-reversed series. This distance is based on a novel stationary ergodic process, in which the stationary series has reversible symmetric features, and is calculated using the Dynamic Time-warping (DTW) algorithm in a self-correlation procedure. Furthermore, to establish a stronger statistical foundation for this method, the F-test is used as a statistical control and is a suggestion for future statistical research on resolving the problem of a sample of limited size being introduced. Finally, as described in the theoretical and experimental documentation, this distance indicates the degree of non-stationarity of the times series. © 2016 van Essen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Avlonitis M.,Ionian University
Engineering Applications of Artificial Intelligence | Year: 2016

Nowadays, early detection of users' interaction outbreaks is one of the most challenging problem in Human-Computer Interaction research. In this paper a new stochastic differential model for outbreaks detection of an arbitrary time series is proposed. The proposed methodology introduces an explicit stochastic differential law for the evolution of outbreaks, mainly a limiting case of the stochastic generalization of the well known Verhustl model. The key feature of the proposed algorithm is a non-linear transformation of the corresponding population state variable. At the end, the detection of an outbreak regime in time is connected with the detection of a time regime over which the transformed variable obeys a random walk stochastic evolution. An application of the proposed algorithm is given for the problem of outbreaks in users' video interactions where the validity and usefulness of the algorithm is tested. © 2016 Elsevier Ltd.

Leftheriotis I.,Ionian University | Leftheriotis I.,Norwegian University of Science and Technology | Giannakos M.N.,Norwegian University of Science and Technology
Computers in Human Behavior | Year: 2014

Social Media have been gaining in popularity worldwide over the last years at an increasingly growing rate. The introduction of social media in companies enables a new method of communication among colleagues and with customers. Although social media are in the top of the agenda for many companies to date, there seems to be very limited understanding of the usage of social media for work purposes. In this study, we investigate whether employees make use of social media for work purposes, what values increase this usage, and if that usage is related with their performance. Responses from 1799 employees in the insurance industry were used to examine the impact of social media on work. Results confirmed that in the case of social media for work, employees make extended use of them no matter their age. We found also that both utilitarian and hedonic values influence employees to use more social media for their work, at least in the insurance sector. Last but not least, this study confirms that there is an important relation between the use of social media and the work performance. © 2013 Elsevier Ltd. All rights reserved.

Kapidakis S.,Ionian University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2016

Metadata harvesting is used very often, to incorporate the resources of small providers to big collections. But how solid is this procedure? Are the metadata providers reliable? How often are the published metadata updated? Are the updates mostly for maintenance (corrections) or for improving the metadata? Such questions can be used to better predict the quality of the harvesting. The huge amount of harvested information and the many sources and metadata specialists involved makes prompt for answers by examining the actual metadata, rather than asking about opinions and practices. We examine such questions by processing appropriately collected information directly from the metadata providers. We harvested records from 2138 sources in 17 rounds over a 3-year period, and study them to explore the behaviour of the providers. We found that some providers are often not available. The number of metadata providers failing to respond is constantly increasing by the time. Additionally, the record length is slightly decreasing, indicating that the records are updated mostly for maintenance/corrections. © Springer International Publishing Switzerland 2016.

Korfiatis N.,Goethe University Frankfurt | Poulos M.,Ionian University
Expert Systems with Applications | Year: 2013

Online consumer reviews play an important role in the decision to purchase services online, mainly due to the rich information source they provide to consumers in terms of evaluating "experience"-type products and services that can be booked using the Internet, with online travel services being a significant example. However, different types of travelers assess each quality indicator differently, depending on the type of travel they engage in, and not necessarily their cultural or age background (e.g. solo travelers, young couples with children etc.). In this study, we present architecture for a demographic recommendation system, based on a user-defined hierarchy of service quality indicator importance, and classification of traveler types. We use an algebraic approach to ascertain preferences from a large dataset that we obtained from the popular travel website using a web crawler and compared with the customer-constructed preference matrix. Interestingly, the architecture of the evaluated recommendation system takes into account already defined demand characteristics of the hotels (such as the number of reviews of specific consumer types compared to the total number of reviews) in order to provide an example architecture for a recommendation system based on user-defined preference criteria. © 2013 Elsevier Ltd. All rights reserved.

Kermanidis K.L.,Ionian University
Journal of Information Hiding and Multimedia Signal Processing | Year: 2011

The present work describes a robust, high-capacity methodology for hiding secret information underneath a Modern Greek cover text by applying shallow syntactic transformations to it. Unlike similar approaches to linguistic steganography, the transfor- mations are extracted automatically by making use of limited external resources, render- ing the process easily portable to other free-phrase-order languages. Their shallow nature and restricted locality does not affect grammaticality, i.e. steganographic security, on the one hand, and, on the other, it ensures higher capacity values than the ones reported in the literature by steganographic systems that are based on syntactic transformations. © 2011 ISSN 2073-4212.

Agency: European Commission | Branch: H2020 | Program: IA | Phase: ICT-17-2014 | Award Amount: 3.27M | Year: 2015

Massive Open Online Courses have been growing rapidly in size and impact. Yet the language barrier constitutes a major growth impediment in reaching out to all peoples and educating all citizens. TraMOOC aims at tackling this impediment by developing high-quality translation of all types of text genre included in MOOCs (e.g. assignments, tests, presentations, lecture subtitles, blog text) from English into eleven European and BRIC languages (DE, IT, PT, EL, DU, CS, BG, CR, PL, RU, ZH) that constitute strong use cases, are hard to translate into and have weak MT support, thus complying with the call objectives. Phrase-based and syntax-based statistical machine translation models will be developed for addressing language diversity and supporting the language-independent nature of the methodology. For a high quality, automatic translation approach and for adding value to existing infrastructure, extensive advanced bootstrapping of new resources will be performed. An innovative multi-modal automatic and human evaluation schema will further ensure translation quality. For human evaluation, an innovative, strict-access control, time- and cost-efficient crowdsourcing setup will be used. Translation experts, domain experts and end users will also be involved. Separate task mining applications will be employed for implicit translation evaluation: (i) topic detection will be applied to source and translated texts and the resulting entity lists will be compared, leading to further qualitative and quantitative translation evaluation results; (ii) sentiment analysis performed on MOOC users blog posts will reveal end user opinion/evaluation regarding translation quality. Results will be combined into a feedback vector and used to refine parallel data and retrain translation models towards a more accurate second-phase translation output. The project results will be showcased and tested on the Iversity MOOC platform and on the VideoLectures.NET digital video lecture library.

Agency: European Commission | Branch: FP7 | Program: MC-ERG | Phase: PEOPLE-2007-2-2.ERG | Award Amount: 45.00K | Year: 2009

The connectivity of distant communities could be reinforced through locative media technologies (e.g., WiFi, Bluetooth, public screens), which lend themselves to shared experiences, such as content sharing and collaborative interaction. In this project, we elaborate on the design aspects and the longitudinal evaluation of a communication system that brings together the physically distributed educational community (students, teaching and administrative staff) of the joint projects that take place in European Unions cultural exchange programs (e.g. eTwinning). There is a significant body of related research, but no integrated approach. In the 70s and 80s, several video-art installations have explored the links between television, architectural space and community identity. During the 90s and onwards, the artistic inspiration has caught on with research labs, which developed several distant communication systems. Nevertheless, previous academic research has not been evaluated with casual users in public spaces for prolonged periods of time. As a matter of fact, the most interesting effects of distance communication systems on everyday life, such as social presence, community awareness, and civic participation have not been documented. We plan to deploy an ambient and social interactive TV platform (physical installation, authoring tools, interactive content) that is easy to use (e.g., presence interfaces) and that supports non-verbal social communication in a positive way. In particular, we focus on a systematical longitudinal evaluation of the social effects of the media communication system on casual users. Besides the foreseen benefits for the local community, the outcomes of this research could have wide applicability in similar community establishments that take place over a distance or in distributed organizations.

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