Smart-Pomodoro is an application aimed at improving efficiency, focus and time management in study sessions for children with Attention-Deficit Hyperactivity Disorder (ADHD). By using Smart-Pomodoro, caregivers can design customized study sessions, thus assisting children to mitigate their ADHD symptoms and influence their motivation. Therefore, the caregiver can set goal-oriented objectives and gamification strategies to make studying more engaging, enhancing self-efficacy, focus, and behaviour. The system also leverages the smartwatch’s features to facilitate clear caregiver–child communication. Accordingly, Smart-Pomodoro employs a real-time, smartwatch-based and rule-driven approach to prompt children to plan and manage their study sessions and breaks. This unique feature delivers real-time feedback and gamification for children with ADHD, while increasing the caregiver’s awareness of their condition and behaviour throughout the session. In the performed evaluation, parents of children with ADHD (from both primary and secondary) rated the system positively, praising its ease of use, usefulness, and effectiveness.

This study compares Desktop, Virtual Reality (VR), and Augmented Reality (AR) versions of the “Attention Robots” game for attention assessment. It aims to determine which setting yields the most accurate measurements and which maximizes engagement. A controlled experiment with 34 university students gathered objective metrics (processing speed, error rate) and subjective data from the Game Experience Questionnaire. Results show the Desktop version produced the strongest attention scores, with faster performance and fewer errors. However, participants rated the VR version as especially engaging and immersive, producing higher flow and sensory-immersion scores. These outcomes highlight a trade-off between reliability and immersion: Desktop is preferable for precise data collection, while VR is superior for motivating users. The AR version fell between these extremes and may be useful when both accuracy and engagement are desired. The findings can inform future clinical, educational, and research tools and technology-based interventions across diverse age groups and contexts.

Abstract Bullying is a complex social issue that requires adaptive and context-aware intervention strategies. This paper presents a multi-agent model that integrates Theory of Mind (ToM), Reinforcement Learning (RL), and Continual Learning (CL) to improve the detection and intervention of bullying behaviors. ToM allows agents to infer the beliefs, intentions, and emotions of others, enabling socially aware decision-making. RL equips the observer agent with the ability to learn from past experiences, refining its intervention strategies dynamically. CL ensures long-term adaptability by allowing the system to retain learned behaviors while continuously adjusting to new bullying patterns. The proposed approach incorporates abstraction mechanisms derived from Theory-Theory (TT) and Simulation Theory (ST), enabling agents to reason about bullying interactions either through predefined rules or simulated experiences. The system has been evaluated in a simulated school environment with varying levels of bullying severity, demonstrating its effectiveness in dynamically adapting intervention strategies. The results indicate that combining ToM, RL, and CL leads to superior performance compared to standard RL-based approaches, particularly in high-risk bullying scenarios. This work provides a foundation for the development of socially intelligent AI systems capable of proactive and context-sensitive intervention in educational settings.

The Digital Twin (DT) concept has evolved into its current definition since its creation in 2003. It now comprises a physical entity and its virtual counterpart, plus their interrelated data connections and uses the virtual counterpart to monitor, simulate, control, and predict the physical entitys behaviour. Most of the proposals in this field have focused on specific use cases rather than on describing the proper guidelines for designing DTs. This paper addresses a significant research challenge by means of a domain-agnostic proposal for DT design. Our new proposal, MAS4DT, is a method for guiding stakeholders in their DT designs following the Multi-Agent Systems (MAS) paradigm, so that the MAS provides the support for the development of the virtual counterpart of the DT. In this work, the application of MAS4DT is illustrated by a DT wind turbine design. We also describe MAS4DTs evaluation in a controlled experiment of its understandability with regard to the 5 dimensions model, another well-known proposal for this type of design. The evaluation was designed considering the properties that a DT should support. The results show that MAS4DT outperforms the 5 dimensions model and indicates its potential use for DT design. Finally, this controlled experiment represents the first empirical validation of proposals for developing D

Despite pilots’ training and technology aids, mid-air collisions can occur and do occur, especially near airfields and in non-controlled airspaces where different kinds of aircraft fly. Technology typically helps pilots in the form of a flat display in the cockpit that shows nearby air traffic. New airliners are now fitted with see-through displays (HUD) to present information right in front of the pilot, and modern military fighters mount that kind of displays in the pilot’s helmet to help them no matter what direction they are looking in. This technology, however, could reach light and sport aviation in the next years thanks to new light and affordable Augmented Reality (AR) glasses, such as the ones targeting applications in urban mobility. Looking ahead to that moment, in this work we rely on Virtual Reality (VR) -in particular, Cardboard VR- to prototype and test different AR interfaces for air traffic alert. Firstly, we proposed and tested four different head-mounted display (HMD) AR interfaces with four pilots in our own VR aircraft-proximity simulator. Then, the two best-scored interfaces were selected for a second evaluation, and they were compared against another proposal (Circular HUD by Alce et al.) and a fixed-mounted (FM) conventional HUD radar (FMHUD Radar), tested by four additional pilots. Overall, pilots showed preference for our AR proposals. Interestingly, pilots with more experience preferred the more conventional, radar-like designs, while those with less flight hours were more open to a different, novel design (HMD 3D Arrow).

: Digital Twins (DTs) are used to augment physical entities by exploiting assorted computational approaches applied to the virtual twin counterpart. A DT is generally described as a physical entity, its virtual counterpart, and the data connections between them. Multi-Agent Systems (MAS) paradigm is alike DTs in many ways. Agents of MAS are entities operating and interacting in a specific environment, while exploring and collecting data to solve some tasks. : This paper presents the results of a systematic literature review (SLR) focused on the analysis of current proposals exploiting the synergies of DTs and MAS. This research aims to synthesize studies that focus on the use of MAS to support DTs development and MAS that exploit DTs, paving the way for future research. : A SLR methodology was used to conduct a detailed study analysis of 64 primary studies out of a total of 220 studies that were initially identified. This SLR analyses three research questions related to the synergies between MAS and DT. : The most relevant findings of this SLR and their implications for further research are the following: i) most of the analyzed proposals design digital shadows rather than DT; ii) they do not fully support the properties expected from a DT; iii) most of the MAS properties have not fully exploited for the development of DT; iv) ontologies are frequently used for specifying semantic models of the physical twin. : Based on the results of this SLR, our conclusions for the community are presented in a research agenda that highlights the need of innovative theoretical proposals and design frameworks that guide the development of DT. They should be defined exploiting the properties of MAS to unleash the full potential of DT. Finally, ontologies for machine learning models should be designed for its use in DT.

Facial affect recognition is a critical skill in human interactions that is often impaired in psychiatric disorders. To address this challenge, tests have been developed to measure and train this skill. Recently, virtual human (VH) and virtual reality (VR) technologies have emerged as novel tools for this purpose. This study investigates the unique contributions of different factors in the communication and perception of emotions conveyed by VHs. Specifically, it examines the effects of the use of action units (AUs) in virtual faces, the positioning of the VH (frontal or mid-profile), and the level of immersion in the VR environment (desktop screen versus immersive VR). Thirty-six healthy subjects participated in each condition. Dynamic virtual faces (DVFs), VHs with facial animations, were used to represent the six basic emotions and the neutral expression. The results highlight the important role of the accurate implementation of AUs in virtual faces for emotion recognition. Furthermore, it is observed that frontal views outperform mid-profile views in both test conditions, while immersive VR shows a slight improvement in emotion recognition. This study provides novel insights into the influence of these factors on emotion perception and advances the understanding and application of these technologies for effective facial emotion recognition training.

Abstract According to the latest statistics, the proportion of the elderly (+65) is increasing and is expected to double within the European Union in a period of 50 years. This ageing is due to the improvement of quality of life and advances in medicine in the last decades. Gerontechnology is receiving a great deal of attention as a way of providing the elderly with sustainable products, environments, and services combining gerontology and technology. One of the most important aspects to consider by gerontechnology is the mobility/rehabilitation technologies, because there is an important relationship between mobility and the elderly's quality of life. Telerehabilitation systems have emerged to allow the elderly to perform their rehabilitation exercises remotely. However, in many cases, the proposed systems assist neither the patients nor the experts about the progress of the rehabilitation. To address this problem, we propose in this paper, a fuzzy‐semantic system for evaluating patient's physical state during the rehabilitation process based on well‐known standard for patients' evaluation. Moreover, a tool called FINE has been developed that facilitates the evaluation be accomplished in a semi‐automatic way first asking patients to carry out a set of standard tests and then inferencing their state by means of a fuzzy‐semantic approach using the data captured during the rehabilitation tasks.

Automatic identification of negative stress is an unresolved challenge that has received great attention in the last few years. Many studies have analyzed electroencephalographic (EEG) recordings to gain new insights about how the brain reacts to both short- and long-term stressful stimuli. Although most of them have only considered linear methods, the heterogeneity and complexity of the brain has recently motivated an increasing use of nonlinear metrics. Nonetheless, brain dynamics reflected in EEG recordings often exhibit a multiscale nature and no study dealing with this aspect has been developed yet. Hence, in this work two nonlinear indices for quantifying regularity and predictability of time series from several time scales are studied for the first time to discern between visually elicited emotional states of calmness and negative stress. The obtained results have revealed the maximum discriminant ability of 86.35% for the second time scale, thus suggesting that brain dynamics triggered by negative stress can be more clearly assessed after removal of some fast temporal oscillations. Moreover, both metrics have also been able to report complementary information for some brain areas.

Abstract As in any other system, an accurate requirements specification is essential to developing a collaborative system, which has special kinds of requirements that are hard to specify by means of current Requirements Engineering techniques. The Collaborative Systems Requirement Modeling Framework (CSRMF) was developed to address this problem; the original Collaborative Systems Requirement Modeling Language was extended and modeled to properly deal with collaboration and awareness requirements. The developed CSRMF framework consists of 3 components: an Requirements Engineering modeling language able to represent collaboration among users as well as awareness needs, a set of design guidelines that drive Computer Supported Cooperative Work system specification by means of 5 different types of diagrams, and a supporting computer‐aided software engineering tool to specify and validate Computer Supported Cooperative Work system requirements. CSRMF provides Requirements Engineers with a complete solution to the specification of awareness‐demanding collaborative systems, as they can now take advantage of a language and a set of guidelines supported by a tool to guide them in specifying system requirements.

This paper seeks to determine how the overlap of several infrared beams affects the tracked position of the user, depending on the angle of incidence of light, distance to the target, distance between sensors, and the number of capture devices used. We also try to show that under ideal conditions using several Kinect sensors increases the precision of the data collected. The results obtained can be used in the design of telerehabilitation environments in which several RGB-D cameras are needed to improve precision or increase the tracking range. A numerical analysis of the results is included and comparisons are made with the results of other studies. Finally, we describe a system that implements intelligent methods for the rehabilitation of patients based on the results of the tests carried out.

Abstract This paper proposes the use of RGB‐D sensors in motor rehabilitation of patients suffering acquired brain injury. Indeed, RGB‐D sensors are promising in their use as assistive technologies in ambient assisted living and rehabilitation places. The paper describes the system developed for creating and monitoring the ambient assisted environment for rehabilitation. The proposal consists of four major tasks: workspace configuration, information integration, user identification, and user tracking. Another main concern in this paper is to assess the user experience of the environment and scenario. A qualitative evaluation of the proposal has been performed to find out how the stakeholders of the proposed RGB‐D assistive technologies environment (injured patients and therapists) use and perceive the ambient assisted rehabilitation room.

Similarly to what happens when designing a single-user system, designers and developers will probably have to address some design problems that have often appeared previously in some other developments. This kind of recurrent problem can be identified, documented and captured in a design pattern that provides a reusable solution to a common problem. The main aim of this work is to provide a design pattern that can be applied to the design of CSCW applications supporting Workspace Awareness (WA). The object-oriented pattern presented answers all WA questions by means of a class structure representing the typical entities and behaviors available in collaborative applications (e.g. users, artifacts, collaborative actions). Moreover, a proof of concept is presented, thus assessing the feasibility of this pattern for a concrete technology, namely C# and Visual Studio 2012.

Interaction is gradually moving from desktop computers to the open air thanks to depth sensors such as Kinect, Xtion and Leap Motion. In this new situation, in which the user is no longer holding any device, the simulation of the sense of touch is progressively gaining more interest. This paper describes how VITAKI, a VIbro Tactile prototyping tool Kit for Eccentric Rotating Mass (ERM) actuators, was used to test different haptic properties of objects in two experiments. VITAKI has been successfully used in the identification of 2D shapes and textures, and 3D shapes. However, there are some haptic properties of objects that have not been simulated using VITAKI yet. These are hardness, temperature, weight and size. This paper describes how VITAKI is used to assess whether differences in weight and size can be discriminated using vibrotactile technology. To analyze these new features, two different experiments were carried out by 18 participants. The results of the experiments are presented in this paper, and allowed us to successfully validate the introduced techniques with a success rate higher than 88% in the case of the size, and between 78 and 85% in the case of the weight, depending on the method used.

The use of haptics in virtual reality and video games has received growing attention as a means of enhancing the sensation of immersion in these environments. The sensation of touching virtual objects not only augments the impression of reality but also can improve the performance. However, the design of haptic interactions is not an easy task, and it usually needs a great effort due to the absence of powerful prototyping toolkits. Thus, this article proposes a vibrotactile prototyping toolkit for Eccentric Rotating Mass actuators named VITAKI. The main objective of this platform is to facilitate the prototyping and testing procedures of new vibrotactile interaction techniques for Virtual Reality and video games. A detailed description of the design of the system is provided, presenting the hardware and software elements that make up the VITAKI toolkit. In addition, its application to two different examples to illustrate its use is provided. Finally, a preliminary evaluation of this toolkit is presented. This evaluation is divided into two main stages. On one hand, a study of Olsen’s criteria is performed to analyze its general capabilities. On the other hand, a comparison with previously presented proposals is included too. These two analyses, together with other experiments where the devices created with the toolkit were tested by end users, highlight its main features and its advantages over other proposals.

In this paper a study is conducted in order to evaluate three different strategies of haptic feedback for texture discrimination in virtual environments. Specifically, both force and vibrotactile feedback have been evaluated, as well as the direct use of the sense of touch, to detect different textures. To this end, a force feedback Phantom device, a custom built vibrotactile data glove and paper palpable prototypes, which represent an ideal model of tactile feedback, have been compared. These three methods have been used to detect two types of patterns, one formed by different geometrical shapes, and the other with different grooves width. Results show that the vibrotactile data glove has a notable behaviour in the detection of textures where the frequency of tactile stimuli varies, and it is even useful to detect more complex textures.

A collaborative system is a distributed software which allows several users to work together and carry out collaboration, communication and coordination tasks. To perform these tasks, the users have to be aware of other user's actions, usually by means of a set of awareness techniques. When we are defining a collaborative system, the awareness techniques can be considered as non-functional requirements bounded to some quality factors, such as usability. However, serious flaws can be found during the specification of these systems if we use the usual Requirement Engineering techniques available, because their expressiveness limitations when dealing with non-functional requirements. In this paper an empirical evaluation is introduced to determine if these techniques are really appropriate to model groupware requirements and which is the best approach to specify this kind of systems. With this aim, a collaborative text editor is used to evaluate whether the current techniques for Requirement Engineering are appropriated or not, exploiting the relation between awareness capabilities and standard quality factors.

This paper analyses the Spatial Model of Interaction, a model that rules the possible interactions among two objects and that has been widely accepted and used in many CVE systems. As a result of this analysis, some deficiencies are revealed and a new model of interaction is proposed. Additionally, a prototype illustrating some of the best features of this model of interaction is detailed.

In the research community, developers of Collaborative Virtual Environments (CVEs) usually refer to the terms awareness and feedback as something necessary to maintain a fluent collaboration when highly interactive tasks have to be performed. However, it is remarkable that few studies address the effect that including special kinds of feedback has on user awareness and task performance. This work follows a preliminary experiment where we already studied awareness in CVEs, evaluating the effect of visual cues in the performance of collaborative tasks and showing that users tend to make more mistakes when such feedback is not provided, that is, they are less aware. These early results were promising and encouraged us to continue investigating the benefit of improving awareness in tasks that require close collaboration between users, but this time analyzing more types of awareness and experimenting with visual, audio and vibrotactile feedback cues.

This paper introduces domain ontology to describe learning materials that compose a course, capable of providing adaptive e-learning environments and reusable educational resources. Two characteristics have been considered to describe each resource: (1) the most appropriate learning style and, (2) the most satisfactory hardware and software features of the used device

From a topological model of a working environment, MigriXML automatically generates a virtual reality environment for controlling the run-time migration of a graphical user interface from one computing platform to another one (e.g., from a desktop to a pocket computer), from one interaction surface to another (e.g., from a laptop to a wall screen) at run-time. For this purpose, any user interface subject to migration is described in USer Interface eXtensible Markup Language regarding its look & feel as well as the platforms and the surfaces involved in the migration. Each interface, in part or in whole, can be attached to a platform or a surface, detached from it, and migrated across platforms or interaction surfaces. Instead of communicating data and code during the migration, the description of the user interface of concern is wirelessly passed from one platform to another one to be regenerated on the target platform. To ensure a continuous control of the run-time migration, MigriXML automatically generates a world model representing the context of use where the source/target platforms/interaction surfaces are represented. Finally, migrating a user interface becomes as natural as its direct manipulation from one platform to another exactly in the same way as it is done on a single platform.

The development of 3D user interfaces is mostly focused on technology and the ways of using it, and so the main concerns are the selection of hardware, software and interaction techniques. The process of development itself is as important as these issues, but it is usually ignored or poorly documented. This paper introduces the TRES-D methodology, and illustrates its application in the development of three different glove-based interfaces, not only to show the benefits of using these devices, but also the benefits of using such a methodological framework.

Along this document, we expose how user interface adaptivity principles may contribute to improve present Web learning systems. If we are able to establish some student features, based on the documents he has consulted, we can easily guide him through our Web site. In order to collect that information, the Web site considers the metadata associated with each document. Once this information has been obtained, the interface recommends the site documents that are the most tailored to the student's interests. Our proposal consists in mixing the main ideas inherent to user profiling, semantic Web, metadata, and ontologies. The framework supporting the initiative is also introduced in this paper.

Abstract While using hierarchical search structures has been proved as one of the most efficient acceleration techniques when rendering complex scenes, automatic creation of appropriate hierarchies is not solved yet. Well‐known algorithms for automatic creation of bounding volume hierarchies are not enough. Higher performance is achieved by introducing spatial uniform subdivision, although algorithms proposed up to now are not truly automatic, as they need some parameters to be adjusted. In this paper we present a full‐automatic hierarchy creation scheme that structures the scene in a hybrid way, combining bounding volumes and voxel grids in the same tree, selecting the search structure that best fits to each scene region. It uses no parameters at all. This efficient proposal relies on a new cost model that estimates the goodness of a hybrid hierarchy if used for rendering the scene. ACM CSS: I.3.7 Computer Graphics—Three‐Dimensional Graphics and Realism

In this paper, we introduce a project that validates the educational capabilities of a game. This game, called Prismaker, incorporates two versions: a physical version and a virtual version. Thus, we want to find out the real potentialities of games in learning processes and to evaluate a single game from two points of view: the physical version and the virtual version that is being developed.

The authors' proposal for ray tracing optimization is based on the combined use of object and ray coherence when tracing beams in scenes subdivided by octrees. With this algorithm they take advantage of the benefits of space subdivision structures (octrees), facilitating that a ray only has to calculate its intersection with a reduced number of objects (those located in the node to which the ray has arrived). On the other hand, the simultaneous tracing of rays integrated in a beam reduces the necessary time to obtain the final image.