Abstract
The use of 360 degrees videos has been increasing steadily in the 2010s, as content creators and users search for more immersive experiences. The freedom to choose where to look at during the video may hinder the overall experience instead of enhancing it, as there is no guarantee that the user will focus on relevant sections of the scene. Visual annotations superimposed on the video, such as text boxes or arrow icons, can help guide the user through the narrative of the video while maintaining freedom of movement. This paper presents a web-based immersive visualizer for 360. videos that contain dynamic media annotations, rendered in real-time. A set of annotations was created with the purpose of providing information or guiding the user to points of interest. The visualizer can be used with a computer, using a keyboard and mouse or HTC Vive, and in mobile devices with Cardboard VR headsets, to experience the video in virtual reality, which is made possible with the WebVR API. The visualizer was evaluated through usability tests, to analyze the impact of different annotation techniques on the users' experience. The obtained results demonstrate that annotations can assist in guiding the user during the video, and a careful design is imperative so that they are not intrusive and distracting for the viewers.

Abstract
Teaching complex assembly and maintenance skills to human operators usually requires extensive reading and the help of tutors. In order to reduce the training period and avoid the need for human supervision, an immersive teaching system using spatial augmented reality was developed for guiding inexperienced operators. The system provides textual and video instructions for each task while also allowing the operator to navigate between the teaching steps and control the video playback using a bare hands natural interaction interface that is projected into the workspace. Moreover, for helping the operator during the final validation and inspection phase, the system projects the expected 3D outline of the final product. The proposed teaching system was tested with the assembly of a starter motor and proved to be more intuitive than reading the traditional user manuals. This proof of concept use case served to validate the fundamental technologies and approaches that were proposed to achieve an intuitive and accurate augmented reality teaching application. Among the main challenges were the proper modeling and calibration of the sensing and projection hardware along with the 6 DoF pose estimation of objects for achieving precise overlap between the 3D rendered content and the physical world. On the other hand, the conceptualization of the information flow and how it can be conveyed on-demand to the operator was also of critical importance for ensuring a smooth and intuitive experience for the operator.

Abstract
The prevention of falls in older adults is an issue that can only be solved with regular exercises, sometimes with the supervision of therapists. This paper presents a game framework that uses devices such as the Wii Balance Board (WBB) to replicate fall-prevention programs, such as the Otago Exercise Programme. The objective is to increase the adherence of senior users to these exercises, while increasing their autonomy by enabling them to conduct unsupervised games. Two interactive games were developed and tested using the WBB and other available devices such as smartphones. The main contribution of this paper is the proposal of several metrics for exergames for the elderly and the combination of digital games with fall-prevention exercises and automatic balance measures based on Centre of Pressure (COP) tracking. © 2019, IFIP International Federation for Information Processing.

Abstract

Abstract
Pedestrian behaviour modelling and simulation play a fundamental role in reducing traffic risks and new policies implementation costs. However, representing human behaviour in this dynamic environment is not a trivial task and such models require an accurate representation of pedestrian behaviour. Virtual environments have been gaining notoriety as a behaviour elicitation tool, but it is still necessary to understand the validity of this technique in the context of pedestrian studies, as well as to create guidelines for its use. This work proposes a proper methodology for pedestrian behaviour elicitation using virtual reality environments in conjunction with surveys or questionnaires. The methodology focuses on gathering data about the subject, the context, and the action taken, as well as on analyzing the collected data to finally output a behavioural model. The resulting model can be used as a feedback signal to improve environment conditions for experiment iterations. A concrete implementation was built based on this methodology, serving as an example for future studies. A virtual reality traffic environment and two surveys were used as data sources for pedestrian crossing experiments. The subjects controlled a virtual avatar using an HTC Vive and were asked to traverse the distance between two points in a city. The data collected during the experiment was analyzed and used as input to a machine learning model capable of predicting pedestrian speed, taking into account their actions and perceptions. The proposed methodology allowed for the successful data gathering and its use to predict pedestrian behaviour with fairly acceptable accuracy. © 2019 IEEE.

Abstract
Healthcare centers are ideal settings to identify and motivate parents to adhere to healthier lifestyles in order to reverse their child's excessive weight. However, such promotions are time- and resource-consuming, and primary health care needs new approaches to engage parents. In this article, we present an app for that purpose, with tailored recommendations for parents regarding young children's lifestyles (eating, drinking, moving, and sleeping habits) with gamification mechanics for parents, and a serious game for their children, aged 3-6 years. Healthcare center based questionnaires were used to assess parent's acceptance of the app. We also determined their enrollment and retention rates with a pilot study, in order to test the implementation of a randomized controlled trial (RCT) in the future (pilot trial registration: ClinicalTrials.gov NCT03881280). In the pilot study, we tested their engagement with the app during a four-week period through a monitoring website. In the acceptance test (n = 13), parents rated the app a median score of seven on a ten-point scale. In the pilot study (n = 21), all parents in the intervention group used the app. The retention rate was 71.4%. This study indicated some areas of improvement related to gaming mechanics in order to increase participation. Healthcare center's professionals and parents of children with overweight/obesity accepted this innovative approach. In addition, it is feasible to test its impact on children's lifestyle by conducting an RCT in the future.