In virtual reality (VR), portals serve as a common metaphor for relocation, allowing users to navigate large virtual environments. However, portal design is often ad hoc, leaving developers without clear principles for their intentional design and placement to support specific experiential or performance goals. We present a taxonomy for VR portals, deconstructing them into three main dimensions: World-related, Portal-related, and User-related. Based on the suggested taxonomy, we implemented eight unique portals varying across three categories: World Integration (Integrated vs. Non-Integrated), Nature Definition (Obvious vs. Subtle/Hidden), and Destination Visibility (Preview vs. Occluded). We assess the impact of these factors, focusing on spatial memory, presence, and experience in a user study with 32 participants. Our results show that World-Integrated portals improve spatial memory and realism, while the exposure of portal’s unusual Nature mainly affects perceived realism. Visibility of the portal’s Destination positively affected user comfort, acceptance, and presence. We discuss the insights for the intentional design of a portal-based relocation techniques that support comfortable and intuitive navigation. Such techniques are particularly suitable for small physical spaces, where portals enable space-efficient, self-overlapping virtual architectures.

This paper presents a gamified Virtual Reality (VR) application integrated with a second-screen Web interface to support exposure therapy for children with sensory food aversion. The system allows therapists to configure therapeutic sessions, monitor user actions in real time, and adapt the virtual environment according to the patient's responses. The Web interface records session data, including behavioral performance and, when available, biosignals such as EEG and ECG, building a historical profile for each patient. The solution was developed through a co-design process with therapists to ensure usability and alignment with therapeutic practice. Preliminary results show the system's potential to improve engagement, support therapist intervention, and enable future developments, such as the integration of real-time neurofeedback to adapt the experience based on physiological data.

Teleportation dominates Virtual Reality (VR) locomotion, known for its efficiency and ease of use, particularly in small physical spaces where users have limited room to move. However, is efficiency the only metric that matters? In this study, we challenge this well-established technique by comparing teleportation with an alternative approach for navigating constrained spaces: Walking-with-Portals. We conducted a user study (N = 24) comparing both techniques, collecting data on orientation, cybersickness, presence, and immersion. Our results reveal a distinct trade-off: Teleportation proved significantly faster, more efficient for pathfinding, and induced less cybersickness. Conversely, Walking-with-Portals significantly enhanced users' sense of spatial presence and perceived control over their movement. While a majority preferred Teleportation for the task's efficiency, 91.7% of participants identified Walking-with-Portals as the more immersive technique. Additionally, we establish key design guidelines for intuitive portal placement that allow a large virtual environment to fit within the small play areas (about 2.5 × 2.5 meters) common to home VR users. Our findings suggest that while teleportation remains the default solution in VR locomotion, Walking-with-Portals provides unique benefits that should not be overlooked. This work invites a reflection on locomotion in VR, arguing that the future of VR navigation may go beyond teleport.

In Virtual Reality (VR), navigating small physical spaces often relies on handheld controllers, such as teleportation and joystick movements, due to the limited space for natural walking. However, walking-based techniques can enhance immersion by enabling more natural movement. This paper presents three room-connection techniques - portals, corridors, and central hubs - that can be used in virtual environments (VEs) to create "impossible spaces". These spaces use overlapping areas to maximize available physical space, promising for walking even in constrained spaces. We conducted a user study with 33 participants to assess the effectiveness of these techniques within a small physical area (2.5 x 2.5 m). The results show that all three techniques are viable for connecting rooms in VR, each offering distinct characteristics. Each method positively impacts presence, cybersickness, spatial awareness, orientation, and overall user experience. Specifically, portals offer a flexible and straightforward solution, corridors provide a seamless and natural transition between spaces, and central hubs simplify navigation. The primary contribution of this work is demonstrating how these room-connection techniques can be applied to dynamically adapt VEs to fit small, uncluttered physical spaces, such as those commonly available to VR users at home. Applications such as virtual museum tours, training simulations, and emergency preparedness exercises can greatly benefit from these methods, providing users with a more natural and engaging experience, even within the limited space typical in home settings.

Virtual Reality (VR) offers an interesting interface for exploring changes in space and time that otherwise could be difficult to simulate in the real world. It becomes possible to distort the virtual world by increasing or diminishing distances, as well as to play with time delays. In this way, it is possible to create different spatiotemporal conditions to study different interaction techniques to analyse which ones are more suitable for each task.

The connection between news and the images that illustrate them goes beyond visual concept to natural language matching. Instead, the open-domain and event-reporting nature of news leads to semantically complex texts, in which images are used as a contextualizing element. This connection is often governed by a certain level of indirection, with journalistic criteria also playing an important role. In this paper, we address the complex challenge of connecting images to news text. A context-enriched Multimodal Transformer model is proposed, NewsLXMERT, capable of jointly attending to complementary multimodal news data perspectives. The idea is to create knowledge-rich and diverse multimodal sequences, going beyond the news headline (often lacking the necessary context) and visual objects, to effectively ground images to news pieces.

Interactive storytelling enables watchers to change the story through an exploratory navigation style. We propose to showcase a collaborative screen to investigate the process of crafting an interactive storytelling animation through the metaphors that built it - from a pre-established database, the watcher can help to create different outputs (e.g. changing sound, color, camera movement, gloss and surface, background and characters). The result is an F-curve graph, time versus animated position, clustering a new layer of added semantic information about the reshaped story.

In this paper we present a virtual reality application, where multiple users can observe and interact with a portion of geo-referenced terrain where a real wildfire took place. The application presents a layout with two maps, one is a three-dimensional view with terrain elevation and the other is a conventional two-dimensional view. The VR users can control different layers (roads, waterways, etc), control the wildfire’s playback, command vehicles to change positions and paint the terrain conveying information to one-another. This work explores how users interact with map visualizations and plan for a crisis management scenario within a virtual environment.

Any software system that has a considerable growing number of features will suffer from essential complexity, which makes the understanding of the software artifacts increasingly costly and time-consuming. A common approach for reducing the software understanding complexity is to use software visualizations techniques. There are already several approaches for visualizing software, as well as for extracting the information needed for those visualizations. This paper presents a novel approach to tackle the software complexity, delving into the common approaches for extracting information about software artifacts and common software visualization metaphors, allowing users to dive into the software system in a live way using virtual reality (VR). Experiments were carried out in order to validate the correct extraction of metadata from the software artifact and the corresponding VR visualization. With this work, we intend to present a starting point towards a Live Software Development approach.

This paper proposes a haptic interaction system for Virtual Reality (VR) based on a combination of tracking devices for hands and objects and a real-to-virtual mapping system for user redirection. In our solution the user receives haptic stimuli by manipulating real objects mapped to virtual ob- jects. This solution departs from systems that rely on haptic devices (e.g., haptic gloves) as interfaces for the user to inter- act with objects in the Virtual Environment (VE). As such, the proposed solution makes use of direct haptics (touching) and redirection techniques to guide the user through the vir- tual environment. Using the mapping framework, when the user touches a virtual object in the VE, he will simultane- ously be physically touching the equivalent real object. A relevant feature of the framework is the possibility to de- fine a warped mapping between the real and virtual worlds, such that the relation between the user and the virtual space can be different from the one between the user and the real space. This is particularly useful when the application re- quires the emulation of large virtual spaces but the physical space available is more confined. To achieve this, both the user's hands and the objects are tracked. In the presented prototype we use a head-mounted depth sensor (i.e., Leap Motion) and a depth-sensing camera (i.e., Kinect). To assess the feasibility of this solution, a functional prototype and a room setup with core functionality were implemented. The test sessions with users evaluated the mapping accuracy, the user execution time and the awareness of the user regarding the warped space when performing tasks with redirection. The results gathered indicate that the solution can be used to provide direct haptic feedback in VR applications and for warping space perception within certain limits.

To assess the success of fall-prevention oriented exergames two digital games were developed taking advantage of the Wii Balance Board (WBB) capabilities. The objective was to evaluate the exergames' potential to address elderly adults' declining motivation to exercise regularly despite the benefits related to fall-prevention. The system uses the WBB to keep track of the player's center of pressure and computes important balance assessment measures related to it to eventually provide a mean to monitor their patients. The presented demo will feature the two exergames.

Image matching algorithms are used in image search, classification and retrieval but are also useful to show how urban structures evolve over time. Images have the power to illustrate and evoke past events and can be used to show the evolution of structures such as buildings and other elements present in the urban landscape. The paper describes a process and a tool to provide a chronological journey through time, given a set of photographs from different time periods. The developed tool provides the ability to generate visualizations of a geographic location, given a set of related images, taken at different periods in time. It automatically processes comparisons of images and establishes relationships between them. It also offers a semi-automated method to define relationships between parts of images.

This paper proposes a framework to support interaction with virtual objects integrated in a real life scenario. In the proposed interaction concept, the user can reshape or re-design a real space using virtual objects using several pictures of the desired space. The images are analyzed for known features such as surfaces, floor or room orientation. Using these elements, it is possible to devise an augmented reality system where the user can add virtual objects to the scenario that react to its content. These are magnetic objects because they attach itself to elements on the scene such as floor or walls. This approach liberates the user from moving objects in three-dimensional space. Instead they just push around objects in a more natural interface. The paper studies the impact of adding these magnetism effects in the interaction with an augmented reality-editing interface.

Many exhibitions that occurred in the past in art museums left a large amount of records (pictures, videos and texts), which are distributed over several documents or places. This paper proposes a multimedia system to reconstruct the heritage and space from such exhibitions. The virtual reconstruction is based on collecting and recovering the documents and making them accessible using an integrated interface. The evolution of image and photograph visualization allows the virtual reconstruction of physical spaces, offering a new dimension of interaction with the user. Through image analysis techniques, the spatial relation between each photo in the archive is accessed allowing the semi-automatic construction of a virtual artwork exhibition.

In this work we present an interactive prototype for an interface that supports the interaction with virtual objects integrated in a real life scenario. The user can reshape or re-design a real space with virtual objects using several pictures of the desired space. The images are analyzed for known features such as surfaces, edges, floor location and room orientation. Using these elements, it is possible to devise an augmented reality system where the user can add virtual objects to the scenario. The smart interface attaches the objects to the scene elements (e.g., floor) automatically. The current demo loads images from user files or takes a snapshot directly from the camera. The high-level features are automatically detected, but can be manually adjusted. A use-case example of an augmented reality application is presented.

This paper addresses the problem of scheduling parallel tasks, represented by a direct acyclic graph (DAG) on heterogeneous clusters. Parallel tasks, also called malleable tasks, are tasks that can be executed on any number of processors with its execution time being a function of the number of processors allotted to it. The scheduling of independent parallel tasks on homogeneous machines has been extensively studied and the case of parallel tasks with precedence constraints has been studied for tree-like graphs. For arbitrary precedence graphs and for heterogeneous machines, the optimization problem is more complex because the processing time of a given task depends on the number of processors and on the total processing capacity of those processors. This paper presents a list scheduling algorithm to minimize the total length of the schedule (makespan) of a given set of parallel tasks, whose dependencies are represented by a DAG