Abstract Face‐to‐face communication relies extensively on non‐verbal cues (NVCs) which complement, or at times dominate, the communicative process as they convey emotions with intense salience, thus definitively affecting interpersonal communication. The capture, transference, and subsequent interpretation of NVCs becomes complicated in computer‐mediated communicative processes, particularly in shared virtual worlds, for which there is growing interest both in regard to NVCs technological integration and their affective impact. This paper presents a between‐groups experimental setup which is facilitated in immersive virtual reality (IVR), and examines NVCs effects on user experience, with special emphasis on degree of attention toward each NVC as an isolated controlled variable of a scripted performance by a virtual character (VC). This study aims to evaluate NVCs fidelity based on the capabilities of the motion‐capture technologies utilized to address cue integration developmental challenges and examines NVCs impact on users' perceived realism of the VC, their empathy toward him, and the degree of social presence experienced. To meet the objectives set the affective impact of low‐fidelity automated NVCs and high‐fidelity real‐time captured NVCs were compared. The findings of the evaluation suggest that although NVCs do impact user experience to an extent, their effects are notably more subtle compared to previous studies.

Feedback provided during Immersive Virtual Reality (IVR) experiences can be delivered through various modalities, such as auditory, visual, and haptic. Most VR systems support vibrotactile haptic feedback and, as several studies point, providing such feedback to users when they interact with Non-Player Characters (NPC) in IVR can have an impact on overall user experience, specifically emotional state, and Body Ownership Illusion. However, most studies regarding haptic feedback impact: (a) focus on users’ perception solely about themselves and do not examine the effect it may have on their perception about others, and (b) implement complex scenarios featuring multiple stimuli sources which may affect the overall users’ response. This work investigates the effect of vibrotactile haptic feedback on users' first impressions of NPCs and their surrounding space. Our evaluation results, provided by thirty (30) participants, showed that integrating vibrotactile haptic feedback for interactions with NPCs in IVR may positively affect users’ first impression of those and their surrounding space as well.

Immersive Virtual Reality (IVR) systems allow for high fidelity interaction techniques using Motion Controllers which resemble users’ hands inside virtual worlds. Recently, many IVR systems allow developers to user Hand Tracking instead of Motion Controllers via infrared depth cameras embedded in Head Mounted Displays (HMDs), which sparked a number of conversations on the effect each interaction method has on user experience in IVR applications. This work presents preliminarily evaluation results of Motion Tracking and Hand Tracking usage on game experience provided by an IVR game. Our results indicate lower usability and learnability levels for hand tracking, which not affect the overall game experience compared to motion controllers.

Immersive Virtual Reality (IVR) systems support several modalities such as body, finger, eye, and facial expressions tracking, thus they can support sign-language-based communication. The combined utilization of tracking technologies requires careful evaluation to ensure high-fidelity transference of body posture, gestures, and facial expressions in real-time. This paper presents the design, development and evaluation of an IVR system utilizing state-of-the-art tracking options. The system is evaluated by certified sign language teachers to detect usability issues and examine appropriate methodology for large-scale follow-up evaluation by users fluent in sign language.

This work preliminary evaluates game experience variations between an N-IVR and an IVR version of a Role-Playing Game (RPG). Our results indicate genre-specific variations in game experience between RPGs and other game genres studied in a similar manner. Moreover, our study identifies prior experience with N-IVR games in general, as well as with N-IVR RPGs, as an important factor affecting game experience in IVR RPGs.

Social psychology has been shedding light for decades to the complexities of interpersonal communication, whilst other fields, such as Computer-mediated Communication, showcase how mediums of communication affect interlocutors to re-negotiate symbolic interactionism. Current developments in Virtual Reality (VR), with the emergence of Social VR among others, compel for a close examination of VR-mediated communication and the probable effects it might have on communicative processes. In this study we conducted an explorative, between-groups comparative experiment, with 51 participants, to establish how susceptible they are to techniques of persuasion and authority when those are filtered through a synthetic environment. As this was an uncharted area of inquiry, our only hypothesis was in reference to level of realness, based on which, face-to-face interactions posed greater probability of participant compliance. Our main findings refute this hypothesis, since the second group (VR) was substantially more susceptible to persuasion techniques.

Mobile Context-Aware Recommender Systems (CARS) have recently emerged aiming at generating recommendations relevant to the specific environmental and situational usage context. This article reports on the design and implementation of a collaborative filtering-based mobile CARS, developed as part of an e-platform that supports location-based search for retail products and services sold by nearby physical retailer shops. In addition to the current user location, our RS considers a multitude of contextual factors like time, season, demographic data, consumer behavior, and location history of the user in order to derive more meaningful product recommendations. The RS has been tested on real operational environments as well as on lab evaluation trials demonstrating higher accuracy and relevance of recommendations against two baseline approaches.

Providing efficient, sustainable and personalized mobility services in urban environments that combine a spectrum of transport modes (e.g., public transport, electric vehicles, vehicle sharing, low energy and/or emission routes) constitutes a great challenge. In this work, we present MOVESMART, a holistic approach (and integrated platform) for the provision of renewable personal mobility services, leveraging crowd-sourcing data, tools for collecting real-time information by multimodal travelers, and traffic prediction mechanisms. MOVESMART guarantees real-time responses to renewable (on-demand) mobility queries for efficient multi-modal route planning that are time-dependent as well as sensitive to aperiodic incidents and traffic prediction forecasts. This paper focuses on the cloudbased (backend) services of the MOVESMART platform.

The environmental impact of the steadily increasing demand for mobility of people and goods, especially in urban environments, raises public concern and presents challenges that need to be addressed in the interest of long-term sustainability. Along this line, the inherently eco-friendly human mobility which involves the use of urban public transit networks must be encouraged and eased. This necessitates the development of context-aware services that hide the complexity of public transit networks while considering all available transportation modalities (e.g. bus, metro, tram, walking and cycling) in order to provide sophisticated route planning tailored to both residents and visitors of urban areas. The EU-funded eCOMPASS research project has addressed this challenge through establishing a methodological framework for route planning optimization. A core objective of the project has been to employ novel algorithm engineering approaches for delivering a comprehensive set of tools and services (accessible from web/mobile application interfaces) for mobile end users to enable eco-awareness in urban multi-modal transfers. eCOMPASS delivered web and mobile services providing multimodal public transportation route planning, considering contextual information as well as various restrictions and/or user constraints. Herein, we report the motivation, main scientific innovations and present the end-products of eCOMPASS with respect to multimodal human mobility.

The recent release of affordable head mounted displays (HMDs) foretells a near future where a variety of social interactions could be taking place in VR environments. There is little knowledge however as to how actual social conditions impact users during a virtual experience. We investigate this issue by placing 54 individuals into a virtual clothing store and having them witness the exposure of their avatar's naked virtual body, being either alone or in the presence of a virtual salesman. Our results indicate that a second character does not affect levels of presence and body ownership illusion, but does cause a strong emotional response, thus suggesting that social context and social presence affectively impact users.

The recent developments in the area of mobile technologies have enabled the diffusion of augmented reality. This article explores new possibilities for leveraging the power of augmented reality, further to its typical use as a means for projecting virtual content over physical objects. That is, it investigates the potential of augmented reality as a tool for participatory content creation and sharing. In order to demonstrate this idea, we have developed Flaneur, a mobile augmented reality application which invites users to wander around a city to discover and highlight its architectural assets. Flaneur serves both as an architectural heritage guide and as a crowdsourcing platform. In particular, further to consuming content edited by administrators, users are enabled to share their knowledge and experiences about heritage buildings through uploading textual and graphical annotation, which is later delivered to peer users as augmented context. The platform allows the documentation of architecture-relevant content either for whole building blocks or even for specific architectural and decorative elements. Moreover, it enables the precise placement and arrangement of digital content over the physical asset to be augmented. Flaneur has been evaluated though field trials, which provided valuable insights as regards the effectiveness, utility and restrictions of the application.

Several mobile guides for unknown destinations provide assistance to tourists (through personalized tour recommendations) in making feasible plans and visiting the most interesting POIs within their available time. However, existing tourist tour planners only regard available attractions as sites lacking physical dimensions (i.e. POIs are treated as points). Although this is adequate for scheduling visits at POIs with single entry/exit points, it fails to capture practical properties of typical tourist visiting styles in urban destinations (e.g. tourists typically enjoy walking on pedestrian zones, market areas and scenic neighborhoods). Herein, we introduce Scenic Athens, a context-aware mobile city guide for Athens (Greece) which delivers personalized tour planning services to tourists deriving near-optimal sequencing of POIs along recommended tours. Scenic Athens takes into account a multitude of travel restrictions and POI properties, also incorporating scenic (walking) routes (in addition to point POIs), thereby supporting more experiential exploration of tourist destinations. A user evaluation study validated the recommendation value, usability and perceived utility of the proposed application.

Pervasive games integrate physical and social aspects of the real world into a unified gaming experience, where virtual and physical game elements co-exist. The blending of game content with the context of the physical environment has been recognized as an important element that increases the enjoyment, interest and engagement of players in in this game genre. To address this requirement most pervasive games prototypes so far have been bound to specific locations, being heavily dependent on orchestration teams to edit game content and support the overall game execution. However, the capacity of pervasive games to be staged anywhere (i.e. their portability) is critical for their wider adoption and commercial success. Since the manual editing of game content by game developers is clearly incompatible with portability, User-Generated Content (UGC) remains as the only practical option for content provision in pervasive games. Nevertheless, the impact of UGC has not been investigated so far in the pervasive games literature. This article introduces Barbarossa, a pervasive role-playing game incorporating UGC as a means for game content generation. The user trials of Barbarossa confirmed that the use of UGC can enhance the quality of experience perceived by players. We also document good practices with respect to the effective incorporation of UGC in pervasive games, which could be useful to future developers.

Tourists become increasingly dependent on mobile city guides to locate tourist services and retrieve information about nearby points of interest (POIs) when visiting unknown destinations. Although several city guides support the provision of personalized tour recommendations to assist tourists visiting the most interesting attractions, existing tour planners only consider walking tours. Herein, we introduce eCOMPASS, a context-aware mobile application which also considers the option of using public transit for moving around. Far beyond than just providing navigational aid, eCOMPASS incorporates multimodality (i.e. time dependency) within its routing logic aiming at deriving near-optimal sequencing of POIs along recommended tours so as to best utilize time available for sightseeing and minimize waiting time at transit stops. Further advancing the state of the art, eCOMPASS allows users to define arbitrary start/end locations (e.g. the current location of a mobile user) rather than choosing among a fixed set of locations. This paper describes the routing algorithm which comprises the core functionality of eCOMPASS and discusses the implementation details of the mobile application using the metropolitan area of Berlin (Germany) as case study.

Pervasive games represent an exciting development in gaming which leverages the use of sensor, visualization and networking technologies to provide immerse live-action game experiences. The field of pervasive games has been intensively researched in the recent years, as evidenced from the proliferation of available prototypes. Existing pervasive game projects commonly do not enable relocation of the game space while also overlooking several aspects which critically affect user acceptance and game experience such as scenario design, usability of employed technologies, game duration and intensity. This article introduces Barbarossa, an outdoor pervasive role-playing game. Barbarossa addresses the abovementioned issues featuring several portable game modes. It also takes into account concrete technology usage requirements for each game mode according to the game session duration and player effort required. Further, game experience is enhanced through incorporating several contextual parameters. User evaluation trials indicated warm reception of Barbarossa by players and confirmed that the main game design objectives have been largely achieved.