Abstract
Virtual Environments (VE) systems may provide a new way to deliver information and services in many areas, for example in tourism, urban planning and education. In urban VE there is a close link between the virtual environment and the urban environment that are intended to represent. These VE can be an intuitive way to access a set of services with a direct association to the real object or entity to which they are related. In this article, we describe a case study that aimed at exploring the possibility of using new interfaces to exploit and use services in urban VE with a greater sense of immersiveness. The results indicate that the VE interfaces are a natural and intuitive access to digital services. While users have felt a greater difficulty in performing some of the tasks in immersive scenario, the majority considered that this scenario provided a greater sense of immersion and realism.

Abstract
HDR video on mobile devices is in its infancy and there are no solutions yet that can achieve full HDR video reproduction due to computational power limitations. In this paper we present a novel and versatile solution that allows the delivery of HDR video on mobile devices by taking into account contextual information and retro-compatibility for devices that do not have the computational power to decode HDR video. The proposed solution also enables the remote transmission of HDR video to mobile devices in real-time. This context-aware HDR video distribution solution for mobile devices is evaluated and discussed by considering the impact of HDR videos over conventional low dynamic range videos on mobile devices as well as the challenge of playing HDR videos directly locally or remotely.

Abstract
This paper presents a study on the evolution of digital skills of a group of people with intellectual disabilities, when performing tasks such as painting, making puzzles, playing games, or word search. For the effect, we compare results in two assessment moments: in the first one, the group with intellectual disabilities had little or no experience as regards as performing universal tasks (selection, manipulation and navigation) and with the Web; in the second one, the group had some experience obtained within the 6 months after the first assessment moment. We aimed at evaluating the evolution of their digital skills by comparing the two assessment moments through the following usability variables: successful conclusion of activities, type of difficulties found, errors, satisfaction, motivation and autonomy indicators. The results revealed that participants showed learning skills when performing all the three universal tasks (namely: selection, manipulation and navigation) which is indicated by the number of participants that was able to conclude the activities, also confirmed by the prominent results of the second assessment moment. When it comes to errors, they made more errors in the first assessment moment, in general. When handling the input devices the participants had a better performance with the mouse than the keyboard. On the other hand, they improved their keyboard handling. However, it was observed that it is not a device that they can be autonomous with due to their reading/writing difficulties, which itself represents a didactic challenge when it comes to the very presentation of appropriate methodologies and techniques that may help them overcome such problem.

Abstract
Navigation in virtual environments is important because it allows the exploration of the virtual worlds. This paper presents an objective performance evaluation (based on the Steering Law) of two types of navigation: natural (real walking) vs. not natural (gamepad). Steering Law was the objective performance metric chosen since it captures the relationship between the time to travel a path and the difficulty of that path. In addition to the performance, subjective metrics were also considered, namely the feeling of presence, cybersickness and user satisfaction. The participants had to complete a series of paths with different difficulty indices and the time that a participant took to go through each one was measured. Overall results show that navigation through real walking had better performance, presence, cybersickness, and satisfaction than the gamepad interface.

Abstract
Virtual Reality offers the possibility of creating the most diverse types of videogames, being possible to have different types of videogames such as calm, eventful or even terrifying. The present study aimed to verify whether different types of videogames have impact on player's emotional responses as wecc as on the self-reported sense of presence. In addition, two distinct display interfaces were considered: conventional computer display and head-mounted display. To carry out this study, an experimental study was designed based on three videogames with distinct natures (exploration, puzzle and horror), where the participants had to fulfill certain tasks within a predetermined period. The data analysis revealed that there no significant emotional changes between the different videogames used. The results also revealed that the use of head-mounted displays increases the sense of presence in scenarios where the field of view is wide.

Abstract
The use of virtual reality in training and simulation as well as the use of haptic feedback are already used in many areas such as medicine, aviation, and training in controlled environments, such as training firefighters. The purpose of this study was the creation of a virtual multisensory environment for the simulation of a training task used in the training of firemen, with the added purpose of studying the impact of the use of haptic feedback on the feeling of presence, satisfaction and performance in the task. For this study a virtual reality experiment was designed to simulate an urban fire environment, where the participants had to train one of the methods used by firefighters in these situations, and the temperature was selected for the haptic feedback. The analysis to the obtained data show that, after doing the experiment, the performance with and without haptic feedback was approximately the same and the participants showed a low error rate. Regarding the sense of presence and satisfaction, the results demonstrate that there was an improvement in the involvement and experienced realism, as well as a low cybersickness value.