Angeliki Antoniou, Dimitris Diakakis, George Lepouras and Costas Vassilakis
To appear in the International Journal of Learning Technology

Abstract
The proposed methodological framework reviews and uses knowledge from the field of cognitive psychology in order to evaluate aspects of educational games. In particular, we concentrate on two components of human cognition that play a central role to learning, namely memory and motivation. After having reviewed theories in the field, we created a questionnaire in order to evaluate educational games. The questionnaire incorporates different experimental findings of cognitive psychology. Especially, we have applied Maslow’s motivation theory, Behavioural findings on reinforcement, experimental findings about attention and memory. We present the results obtained from the evaluation of two games, PAC-MAN and Mega Jump. The results confirmed the user ratings of the two games, showing that there seem to be cognitive reasons for the success/failure of different games. Finally, lists of guidelines for developers and instructors are included.

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G.R.S. Weir, G. Lepouras
Proceedings of 2nd World Multiconference on Systemics, Cybernetics and Informatics, Orlando, Florida, USA, July 1998.

Abstract:

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G.R.S. Weir, G. Lepouras,
short paper, Proceedings of ICALT 2001, IEEE International Conference on Advanced Learning Technologies Madison, USA, August 6-8, 2001.

Abstract:

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N. Aktipis, P. Georgiadis, N. Kolomvos, G. Lepouras
Proceedings of the 4th Panhelenic Conference in Informatics, Vol. II, pp. 403-413, 1993.

Abstract:

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Weir, G.R.S., Ozasa, T., Lepouras, G.
JALTCALL 2004, June 2004, Japan.

Abstract:

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G. Lepouras, G.R.S. Weir
ACM SigCHI Bulletin, Vol.31, No.2, pp. 17-24, April 1999.

Abstract:

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G.R.S. Weir, G. Lepouras
proceedings of Human Computer Interaction International 2001, New Orleans, USA, August 5 - 10, 2001.

Abstract:

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G.R.S. Weir, G. Lepouras, U. Sakellaridis
People and Computers XI, M.A. Sasse, R.J. Cunnigham, and R.L. Winder (Eds), pp. 129-138, proceedings of Human Computer Interaction '96, Springer, ISBN 3-540-76069-5.

Abstract:

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G. Lepouras, G.R.S. Weir
In International Journal of Human Computer Studies, 59 (2003), 941-957.

Abstract:

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G.R.S. Weir, G. Lepouras
Proceedings of Human Computer Interaction International 2003.

Abstract:

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Daradimos Ilias, Costas Vassilakis Akrivi Katifori
poster presentation in the International Symposium on "Information & communication technologies in cultural heritage", Ioannina, Greece, October 16-18, 2008

Abstract:

Digitization efforts and web presentations are currently on-going in many museums, archives, libraries and culture heritage institutions in general, exploiting the advent of WWW and digitization technologies. The main benefits from these efforts are exhibit cataloguing, their effective management, preservation and showcasing, and their presentation to the public through the WWW. However, many museums, especially the smaller ones, cannot afford a commercial product and resort to using simple static web pages for their web presence and exhibit presentation. Content Management Systems (CMS), especially open-source ones which come with practically zero-cost, are more and more frequently adopted by museums to create and maintain their website, since they simplify the creation and editing of the web pages and may be used by non-computer experts. In this work we present a module for the Drupal CMS, which provides functionality for (a) Database schema extension to accommodate museum exhibit and collection information (b) Digital exhibit representation (DER) management. (c) Provision of administration pages through which the museum personnel may enter and manage exhibit and collection information (d) WWW scowcasing and (e) Batch data import/export, to facilitate information exchange with other museums.

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Victor Mateevitsi, Michael Sfakianos, George Lepouras, Costas Vassilakis
Proceedings of ACM DIMEA 2008

Abstract:
In this paper we present a system that facilitates virtual museum development and usage. The system is based on a game engine, ensuring thus minimal cost and good performance, and includes provisions that enable museum curators design the virtual museum without any specialized knowledge. Besides visual and auditory information, museum curators may also provide metadata which provide additional information to the visitor, while they can be also exploited for searching for exhibits with certain properties. A guide is also included in the museum, to present additional information to the visitors and aid them throughout their tour.

The article is available through the ACM author-izer service:

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Angeliki Antoniou, George Lepouras and Costas Vassilakis
DESIDOC Journal of Library and Information Technology, Special Issue on Online Exhibitions

Abstract:

The process of designing systems or products largely depends on a number of decisions, like "who do I design for?", "what should my product do?", "what are the user requirements?" etc. The developing teams usually base their decisions on experience and/or heuristics and this is particularly the case, in the development of online products and especially online exhibitions. The different solutions are frequently case studies of specific museums or institutions that wish to provide online content to actual or possible visitors. In addition, the interdisciplinary nature of the endeavor, involving museology, technology but also education, poses important design problems. In the following sections, we present a generic methodology for the design of online exhibitions, using top-down processes and transferable findings across museum types that wish to assist the designers during the early decision stages.

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George Lepouras and Costas Vassilakis
book chapter in the book "Adaptable and Adaptive Hypermedia Systems" Sherry Y. Chen and George Magoulas (eds), 2005.

Abstract:
This chapter presents an architecture for supporting the creation of adaptive virtual reality museums on the web. It argues whether the task of developing adaptive virtual reality museums is a complex one, presenting key challenges, and should thus be facilitated by means of a supporting architecture and relevant tools. The proposed architecture is flexible enough to cater for a variety of user needs, and modular promoting extensibility, maintainability and tailorability. Adoption of this architecture will greatly simplify the development of adaptive virtual reality museums, reducing the needed effort to exhibit digitisation and user profile specification; user profiles are further refined dynamically through the user data recorder and the user modelling engine, which provide input for the virtual environment generator.

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D. Charitos, G. Lepouras, C. Vassilakis, V. Katifori and L. Halatsi
Proceedings of the seventh UK VR-SIG Conference, Glasgow, 2000.

Abstract:
The current paper describes an approach to designing and implementing a virtual environment comprising ten different museums. The number of museums as well as the variety of their exhibits lead to the adoption of a generalised strategy that catered for all museum presentation needs and allowed for future expansion. Furthermore, the system architecture supports the delivery of multimedia content either over the Internet or via a local immersive virtual reality installation.

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G. Lepouras
to appear in Journal of Computational Methods in Sciences and Engineering

Abstract:
The emergence of the World Wide Web during the past few years has provided a medium for communicating information faster and to more people than before. The technologies used allow for the development of personalised, adaptive to the users’ needs, information systems. So far, the complexity of the design and implementation of Virtual Environments has restricted their usage in locally executed, stand-alone applications. In this paper we propose an architecture that permits and facilitates the dynamic, on-the-fly creation of Virtual Environments on the Web that adapt to the users’ preferences and profiles. We focus on the algorithms available for creating an efficient virtual environment generation engine. We illustrate the proposed architecture with examples from a case study of a Virtual Museum.

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G. Lepouras, D. Charitos, C. Vassilakis, A Charissi and L. Halatsi
Third International Virtual Reality Confere nce, VRIC2001, Laval, France, May 16-20, 2001.

Abstract:
Past years have seen the exploitation of multimedia techniques and lately the introduction of virtual reality methods to create new forms of presentation for museums' exhibitions. Virtual Reality can offer a number of advantages to museums, offering a way to overcome some common problems like the lack of space or the need of visitors to interact with the exhibits. A broad categorisation of virtual museums reveals that they vary from fully immersive cave systems to simple multimedia presentations. In our approach to develop a virtual reality museum we have designed a virtual environment (VE) where guests can visit a total of ten different museums. The processes of digitisation, architectural design and exhibit presentation are outlined and points of particular importance are explained. Exhibits from the real world museums have been digitised and integrated in the VE. The system has been implemented in two versions: one fully immersive and one with a stereo display.

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D. Charitos, G. Lepouras, C. Vassilakis, V. Katifori, A. Charissi, L. Halatsi
Proceedings of the VAST2001 Symposium, November 2001, Athens, Greece.

Abstract
A virtual environment system installed within a real museum can offer a number of advantages, which are discussed in this paper: overcoming the lack of exhibition space, responding to the need for interaction with certain exhibits, affording easy transfer of exhibitions to remote sites. This paper also presents an approach towards designing and developing a virtual reality museum comprising ten different museums. The processes of digitisation, architectural design and exhibit presentation are outlined and points of particular importance are explained. Exhibits from real world museums have been digitised and integrated in this VE.

Article available through the ACM AUthro-izer service:

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George Lepouras, Akrivi Katifori, Costas Vassilakis, Anna Charissi
Proceedings of HCI 2003, vol. 4, pp. 1143-1147.

Abstract
The paper presents an environment that enables museum curators to catalogue and publish on the web exhibits in multiple languages and media including 3D, video, images. The system is extendable to accommodate new media types, languages, exhibits, information categories, etc. Visitors have the potential to formulate dynamic personalised exhibit collections using search mechanisms provided by the system.

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George Lepouras, Akrivi Katifori, Costas Vassilakis, Dimitrios Charitos
Virtual Reality Journal, Springer-Verlag, Vol 7, No 2, (2003), pp. 120-128

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.

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Angeliki Antoniou, Ioanna Lykourentzou, Jenny Rompa, Eric Tobias, George Lepouras, Costas Vassilakis, Yannick Naudet
Proceedings of the GALA 2013 conference, Paris, October 2013.

Abstract:
This paper presents an innovative approach based on social-network gaming, which will extract players’ cognitive styles for personalization purposes. Cognitive styles describe the way individuals think, perceive and remember information and can be exploited to personalize user interaction. Questionnaires are usually employed to identify cognitive styles, a tedious process for most users. Our approach relies on a Facebook game for discovering potential visitors’ cognitive styles with an ultimate goal of enhancing the overall visitors' experience in the museum. By hosting such a game on the museum’s webpage and on Facebook, the museum aims to attract new visitors, as well as to support the user profiling process.

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George Lepouras, Costas Vassilakis
Virtual Reality Journal, Springer-Verlag, Vol. 8, No. 2, (2004), pp. 96-106.

Abstract
Museums have started to realise the potential of new technologies for the development of edutainment content and services for their visitors. Virtual reality technologies promise to offer a vivid, enjoyable experience to the museums guests, but the cost in time, effort and resources can prove to be overwhelming. In this paper, we propose the use of 3D game technologies for the purpose of developing affordable, easy to use and pleasing virtual environments. To this end, we present a case study based on an already developed version of a virtual museum and a newly implemented version that uses game technologies. The informal assessment indicates that game technologies can offer a prominent and viable solution to the need for affordable desktop virtual reality systems.

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G. D. Magoulas, G. Lepouras, C. Vassilakis
Virtual Reality Journal, Special issue "Virtual reality in the e-Society", editorial preface

Abstract:
This special issue explores the extent to which virtual reality (VR) is affecting the creation of an electronic society. E-Society is a broad term used to describe a research area covering aspects of digital technologies for large user communities. Recent years have seen the emergence of various electronic services in an attempt to facilitate everyday life and improve the way common tasks are being carried out. Ôhe term e-Society covers a wide range of applications from e-government, e-democracy, and e-business to e-learning and e-health. In order for VR to contribute to the creation and advancement of e-Society, a number of issues have to be tackled. A successful VR system has to find a balance between the hardware requirements, user interaction methods, content presentation and the effort required for development and maintenance. Hardware requirements define to a large degree the extent to which an end-user can afford to execute the VR system at her home. User interaction methods have to cater for the variety of users¢ needs. Overall, design and implementation of a successful and engaging VR system is a rather difficult and complex task which requires increased effort in human power and resources in comparison to typical window based applications. Flexibility in development and subsequently maintenance of such a system can be achieved by adopting techniques already present in rapid application development environments, like abstraction, automatic code generation and reusability.

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Ioannis Bourlakos, Manolis Wallace, Angeliki Antoniou, Costas Vassilakis, George Lepouras and Anna Vassiliki Karapanagiotou
Proceedings of the third International KEYSTONE Conference, (IKC2017)

Abstract:
There is a wide range of meta-data standards for the documentation of museum related information, such as CIDOC-CRM; these standards focus on the description of distinct exhibits. In contrast, there is a lack of standards for the digitization and documentation of the routes followed and information provided by museum guides. In this work we propose the notion of the narrative, which can be used to model a guided museum visit. We provide a formalization for the narrative so that it can be digitally encoded, and thus preserved, shared, re-used, further developed and exploited, and also propose an intuitive visualization approach.

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Marinos Theodorakopoulos, Nikos Papageorgopoulos, Andriana Mourti, Angeliki Antoniou, Manolis Wallace, George Lepouras, Costas Vassilakis and Nikos Platis
Proceedings of SMAP 2017

Abstract:
In this short paper we examine the suitability of the Google Cardboard as a means for the delivery of personalized cultural experiences. Specifically, we develop the content and create the application required in order to provide highly personalized visits to the Archaeological Museum in Tripolis, Greece. We also examine the usability issues related to the use of Google Cardboards. Early results are promising, and based on them we also outline the next steps ahead.

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Angeliki Antoniou, Costas Vassilakis, Anastasios Theodoropoulos, George Lepouras
Proceedings of the “Cultural informatics research and applications: State of the art and open challenges” workshop, within the Euromed 2018 Conference, 2018,

Abstract:
The Human-Computer Interaction and Virtual Reality Lab, at the Department of Informatics and Telecommunications of the University of Peloponnese, aims to conduct high quality research in areas related to the analysis, design, develop-ment, and evaluation of HCI and VR systems and applications, and in parallel to support the teaching requirements of the department in the respective field. Over the last years the HCI-VR lab particularly focuses on Cultural Heritage and de-velops technologies primarily for spaces of cultural heritage that cover the diverse needs of heterogeneous audiences providing holistic visitor experience. The HCI-VR lab is actively participating in National and European projects on Cultural Heritage, such as FP7 Experimedia (https://hci-vr.dit.uop.gr/experimedia), H2020 CrossCult (www.crosscult.eu) and multiple projects from the National Strategic Reference Framework.

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Akrivi Katifori , Elena Torou, Constantin Halatsis, Lepouras Georgios and Costas Vassilakis
Proceedings of the IV 06 Conference.

Abstract:
The continuing need for more effective information retrieval has lead to the creation of the notions of the semantic web and personalized information management, areas of study that very often employ ontologies to represent the semantic context of a domain. Consequently, the need for effective ontology visualization for design, management and browsing has arisen. There are several ontology visualizations available through the 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 the preliminary results of an evaluation of four visualization methods in Protégé.

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Maria Golemati, Constantin Halatsis, Costas Vassilakis, Akrivi Katifori, Georgios Lepouras
Proceedings of the IV 06 Conference.

Abstract:
Digital libraries and historical archives are increasingly employing visualization systems to facilitate the information retrieval and knowledge extraction tasks of their users. Typically, each organization employs a single visualization system, which may not suit best the needs of certain user groups, specific tasks, or properties of document collections to be visualized. In this paper we present a context-based adaptive visualization environment, which embeds a set of visualization methods into a visualization library, from which the most appropriate one is selected for presenting information to the user. Methods are selected by examining parameters related to the user profile, system configuration and the set of data to be visualized, and employing a set of rules to assess the suitability of each method. The presented environment additionally monitors user behavior and preferences to adapt the visualization method selection criteria.

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Maria Golemati, Akrivi Katifori, Eugenia G. Giannopoulou, Ilias Daradimos, Costas Vassilakis, George Lepouras, Constantin Halatsis
Proceedings of IV 08,

Abstract
Hierarchically structured data collections often need to be visualized for the purposes of digital information management and presentation. File browsing, in particular, has an inherent hierarchical structure and plays an important role in the context of Personal Information Management (PIM). A multitude of file browsers are nowadays available, offering different functionalities, while users adopt diverse practices and habits for browsing activities. In this paper, we investigate these aspects to obtain insights into their advantages and disadvantages and suggest solutions in the area of PIM, as well as in other domains employing similar visualization paradigms. The presented study focuses on the two most widespread visualizations used by file browsers, namely the indented list and zoomable interface paradigms, and assesses their effectiveness for various tasks and contexts, both by exploiting results on existing evaluations on hierarchy visualizations and folder hierarchy visualizations in particular, and by conducting an interview-based user study.

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Maria Golemati, Costas Vassilakis, Akrivi Katifori, George Lepouras, Constantin Halatsis
Chapter in "Intelligent User Interfaces: Adaptation and Personalization Systems and Technologies"

Abstract:
Novel and intelligent visualization methods are being developed in order to accommodate user searching and browsing tasks, including new and advanced functionalities. Besides, research in the field of user modeling is progressing in order to personalize these visualization systems, according to its users' individual profiles. However, employing a single visualization system, may not suit best any information seeking activity. In this paper we present a visualization environment, which is based on a visualization library, i.e. is a set of visualization methods, from which the most appropriate one is selected for presenting information to the user. This selection is performed combining information extracted from the context of the user, the system configuration and the data collection. A set of rules inputs such information and assigns a score to all candidate visualization methods. The presented environment additionally monitors user behavior and preferences to adapt the visualization method selection criteria.

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Maria Golemati, Akrivi Katifori, Eugenia G. Giannopoulou, Ilias Daradimos, Costas Vassilakis
Proceedings of the Information Visualization 07 Conference.

Abstract:
The visualization of hierarchies is very important for digital information management and presentation systems. Especially in the context of Personal Information Management, file browsers play a very important role. Currently the most common file browser visualizations are Windows Explorer and the simple zoomable visualization offered by Microsoft Windows. This work explores the issue of file browser visualization through a user study based on interviews and an experiment.

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Akrivi Katifori, Elena Torou, Costas Vassilakis, Georgios Lepouras, Constantin Halatsis
Proceedings of IEEE RCIS 2008.

Abstract:
TThe 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 Protégé.

Note: This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.

Akrivi Katifori, Elena Torou, Costas Vassilakis, Constantin Halatsis
Proceedings of IV 08,

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.

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Akrivi Katifori , Costas Vassilakis, George Lepouras, Elena Torou, Constantin Halatsis and
Proceedings of SMAP 2014

Abstract:
Incorporating digital tools in the business and scientific research workflows is at the moment an on-going process, challenging and demanding as every domain has its own needs in terms of data models and information retrieval methods. The information in some domains involves entity evolution, a characteristic that introduces additional tasks, such as finding all evolution stages of an entity, and poses additional requirements for the information retrieval process. In this paper we present a user study aiming to investigate the effectiveness of current ontology browsing and visualization methods for supporting users in tasks involving research on entity evolution.

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Golemati, Marianthi, Vassilakis, Costas, Katifori, Akrivi, Lepouras, George, Halatsis, Constantin
Poster presentation in IV 09

Abstract:
Hierarchical data structures are one of the most commonly used data structures in computer science, and therefore numerous methods and techniques have been proposed for their visualization. In this paper, we present our findings from a user study, in which a number of folder visualization environments were evaluated to assess (a) how efficiently a number of tasks can be performed within the different environments (b) the extent to which using a particular visualization may help the user acquire an accurate cognitive image of the hierarchy structure and its contents and (c) the overall user experience from using a particular visualization environment. The visualization environments considered are representative of major visualization paradigms (zoomable user interfaces, context+focus and space-filling), while both 2D and 3D environments have been included.

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Katifori Akrivi, Vassilakis Costas, Lepouras Georgios, Daradimos Ilias, Halatsis Constantin
Proceedings of the ACM Advanced Visual Interfaces 06 Conference.

Abstract:
Most ontology development methodologies and tools for ontology management deal with ontology snapshots, i.e. they model and manage only the most recent version of ontologies, which is inadequate for contexts where the history of the ontology is of interest, such as historical archives. This work presents a modeling for entity and relationship timelines in the Protégé tool, complemented with a visualization plug-in, which enables users to examine entity evolution along the timeline.

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