George E. Raptis

• Doctor of Philosophy
• Researcher at Human Opsis

Mixed-reality environments introduce innovative human-computer interaction paradigms assisted by enhanced visual content presentation which require from end-users to perform excessive cognitive tasks related to visual attention, search, processing, and comprehension. In such visually enriched interaction realms, individual differences in perception...

The heterogeneity of the audience of cultural heritage institutions introduces numerous challenges to the delivery of the content. Considering that people differ in the way they perceive, process, and recall information and that their individual cognitive differences influence their experience, performance, and knowledge acquisition when performing...

In the cultural heritage domain, games have been used to engage users into an active state of learning through immersive and playful interactions that include visually enriched interaction contexts. There is evidence that individual differences in the inherent way people search, process, analyze, comprehend, store, and retrieve visual information i...

Recent research provides evidence that individual differences in human cognitive styles affect user performance and experience in diverse application domains. However, state-of-the-art elicitation methods of cognitive styles require researchers to apply explicit, in-lab, and time-consuming "paper-and-pencil" techniques, rendering real-time integrat...

Stimulated by a large number of different theories on human cognitive processing, suggesting that individuals have different habitual approaches in retrieving, recalling, processing and storing information, this paper investigates the effect of field dependence/independence with regards to game players' performance in the context of a cultural heri...

In a fast-changing media ecosystem, professionals and enterprises in the News and Media industry face new challenges that they should address to maximize their productivity and improve their services. The rise of alternative news sources, such as social media, the leading news source, especially for young people, has led to emerging requirements in...

Cognitive theories suggest that people differ in processing information, reflecting their different cognitive styles. Research in Human-Computer Interaction has revealed that people with different cognitive styles develop different strategies, achieve different performances, and have different experiences when interacting with information systems....

Security mechanisms based on patterns, such as Pattern Lock, are commonly used to prevent unauthorized access. They introduce several benefits, such as ease of use, an additional layer of security, convenience, and versatility. However, many users tend to create simple and easily predictable patterns. To address this issue, we propose a data-driven...

Connected and automated vehicles (CAVs) are getting a lot of attention these days as their technology becomes more mature and they benefit from the Internet-of-Vehicles (IoV) ecosystem. CAVs attract malicious activities that jeopardize security and safety dimensions. The cybersecurity systems of CAVs detect such activities, collect and analyze rela...

The richness of tangible and intangible cultural heritage (CH) poses great opportunities and challenges in the development of successful information and communications technology (ICT) tools for its curation, exploration and fruition [...]

Theories in cognitive psychology suggest that people differ in the way we process information as we tend to develop different cognitive styles. Recent research in Human-Computer Interaction has revealed that people who have different cognitive styles tend to develop different strategies, achieve different performance, and have different experience...

In multiplayer collaborative games, players need to coordinate their actions and synchronize their efforts effectively to succeed as a team, thus individual differences have the potential to impact teamwork and gameplay. This paper investigates the effects of cognitive styles on teams engaged in collaborative gaming activities. Fifty-four individua...

Cultural heritage is a challenging domain of application for novel interactive technologies, where varying aspects in the way that cultural assets are delivered play a major role in enhancing the visitor experience, either onsite or online. Technology-supported natural human–computer interaction that is based on multimodalities is a key factor in e...

For the past 20 years, researchers have investigated the use of eye tracking in security applications. We present a holistic view on gaze-based security applications. In particular, we canvassed the literature and classify the utility of gaze in security applications into a) authentication, b) privacy protection, and c) gaze monitoring during secur...

Cultural heritage (CH) institutions attract wide and heterogeneous audiences, which should be efficiently supported and have access to meaningful CH content. This introduces numerous challenges when delivering such experiences, given that people have different cognitive characteristics which influence the way we process information, experience, beh...

People use various techniques and tools to perform spatial navigation tasks, such as asking a local person for instructions in order to reach a destination or creating a detailed route plan for their trip through technology-mediated tools. Novel technologies, such as augmented reality, have been introduced to improve the performance and enhance the...

The heterogeneity of the audience of cultural heritage (CH) institutions introduces numerous challenges to the delivery of meaningful CH content. People with diverse cognitive characteristics are engaged with varying CH activities (e.g., games, guided visits) and considering that cognitive characteristics define the way we process information, our...

Referees' decisions in sport games, which must be made in less than a second, have an impact on the games' outcome. The use of hardware and/or software solutions could contribute towards increased accuracy of referees' decisions. Application of such solutions can be expensive, especially in the case of less popular sports. In this respect, we propo...

Two-factor authentication (2FA) provides an extra layer of security as it requires two pieces of evidence to be provided to an authentication mechanism before granting access to a user. However, people do not prefer 2FA; a reason for this is that 2FA requires performing extra actions. In this late-breaking work, we present UltraSonic Watch which pr...

In multiplayer games, players need to coordinate action to succeed. This paper investigates the effect of cognitive styles on performance of dyads engaged in collaborative gaming activities. 24 individuals took part in a mixed methods user-study; they were classified as field dependent (FD) or independent (FI) based on a cognitive style elicitation...

More and more people use software applications and the Internet in their daily routine. Cultural heritage has been a favored domain for using such interactive software systems. Heritage sites, cultural institutions, and travel agencies provide visitors with digital applications, such as information retrievers and guides, aiming to enhance their vis...

In this paper, we introduce a two-step method for estimating the strength of user-created graphical passwords based on the eye-gaze behaviour during password composition. First, the individuals' gaze patterns, represented by the unique fixations on each area of interest (AOI) and the total fixation duration per AOI, are calculated. Second, the gaze...

Cultural Heritage (CH) is a challenging domain of application for novel Information and Communication Technologies (ICT), where visualization plays a major role in enhancing visitors' experience, either onsite or online. Technology-supported natural human-computer interaction is a key factor in enabling access to CH assets. Advances in ICT ease vis...

Nowadays, technological advances introduce new visualization and user interaction possibilities. Focusing on the user authentication domain, graphical passwords are considered a better fit for interaction environments which lack a physical keyboard. Nonetheless, the current graphical user authentication schemes are deployed in conventional layouts,...

Comprehension of visual content is linked with the visitor's experience within cultural heritage contexts. Considering the diversity of visitors towards human cognition, in this paper, we aim to investigate whether cognitive characteristics are associated with the comprehension of cultural-heritage visual content. We conducted a small-scale eye-tra...

Visual attention, search, processing and comprehension are important cognitive tasks during a graphical password composition activity. Aiming to shed light on whether individual differences on visual behavior affect the strength of the created passwords, we conducted an eye-tracking study (N=36), and adopted an accredited cognitive style theory to...

Evidence suggests that individual cognitive differences affect users' memorability, visual behavior, and graphical passwords' security. Such knowledge denotes the added value of personalizing graphical password schemes towards the unique cognitive characteristics of the users. However, real-time and accurate cognition-based predictive user models a...

The monitoring of pancreas-related health issues in real-time and outside the medical room is a challenge in the wide e-health domain. This paper introduces WHEAMO, a novel e-health platform which employs medical implants (biosensors), which function as antennas, planted in the pancreas. WHEAMO uses wireless in-body propagation to track, monitor, a...

Image-based rendering and reconstruction (IBR) approaches minimize time and costs to develop video-game assets, aiming to assist small game studios and indie game developers survive in the competitive video-game industry. To further investigate the interplay of IBR on developers’ efficiency, game performance, and players’ gaming experience we condu...

Common design practices of current cultural heritage activities barely take into account the contextual, cultural, and cognitive characteristics of visitors. Bearing in mind that information processing is substantial in such activities, this paper investigates the interplay among human cognitive differences and cultural heritage gaming activities t...

Recent research provides evidence that individual differences on human cognitive strategies affect user performance and experience in diverse application domains. However, state-of-the-art elicitation methods of human cognitive strategies require from researchers to apply explicit, in-lab, and time-consuming "paper-and-pencil" techniques, compromis...

Kinetics and kinematics have been the focus of a lot of research throughout the years, and technological advances have contributed towards advanced monitoring and analysing of motion. Focusing on Trendelenburg Gait, an abnormal gait, a personalisation framework for monitoring and evaluating the movement is proposed in this paper based on a number o...

Being the windows to the soul, eyes reveal information about individuals' feelings, emotions and behaviour, affecting various cognitive tasks, such as focus of attention, spatial cogni-tion and navigation, cognitive load, etc. With the increased use of computer systems, complex information is visualized and communicated through visual interfaces as...

Based on a large number of different cognitive theories on information processing procedure, suggesting that individuals have different approaches in the way they forage, retrieve, process, store and recall information, this paper investigates the effect of field dependence/ independence with regards to visual attention of gamers in the context of...

Business managers support that decisions based on data analysis are better decisions. Nowadays, in the era of digital information, the accessible information sources are increasing rapidly, especially on the Internet. Also, the most critical information for business decisions is hidden in a large amount of unstructured data. Thus, Big Data analytic...

Retrieving, recalling, processing, organising and storing information are integral parts of the human information seeking process and many socio-cognitive theories suggest that the approach of the seekers is closely related to their cognitive processing styles and abilities. The aim of this study is to investigate the impact of wholistic-analytic c...

We report the design of a system which integrates a suite of tools to allow scholars to manage related documents in their personal digital stores. VirDO provides a virtual workspace in which pdfs can be placed and displayed, and which allows these documents to be manipulated in various ways that prior literature suggests to be useful. Particularly...

[author's copy, greek: http://hci.ece.upatras.gr/images/Papers/c165-katsini_etal_2010_sfhmmy.pdf]