Rafael Rieder

A methodology to specify three-dimensional interaction using Petri Nets

This work presents a methodology to formally model and to build three-dimensional interaction tasks in virtual environments using three different tools: Petri Nets, the Interaction Technique Decomposition taxonomy, and Object-Oriented techniques. User operations in the virtual environment are represented as Petri Net nodes; these nodes, when linked, represent the interaction process stages. In our methodology, places represent all the states an application can reach, transitions define the conditions to start an action, and tokens embody the data manipulated by the application. As a result of this modeling process we automatically generate the core of the applications source code. We also use a Petri Net execution library to run the application code. In order to facilitate the application modeling, we have adapted Dia, a well-known graphical diagram editor, to support Petri Nets creation and code generation. The integration of these approaches results in a modular application, based on Petri Nets formalism that allows for the specification of an interaction task and for the reuse of developed blocks in new virtual environment projects.

Identifying relationships between physiological measures and evaluation metrics for 3D interaction techniques

This project aims to present a methodology to study the relationships between physiological measures and evaluation metrics for 3D interaction techniques using methods for multivariate data analysis. Physiological responses, such as heart rate and skin conductance, offer objective data about the user stress during interaction. This could be useful, for instance, to evaluate qualitative aspects of interaction techniques without relying on solely subjective data. Moreover, these data could contribute to improve task performance analysis by measuring different responses to 3D interaction techniques. With this in mind, we propose a methodology that defines a testing protocol, a normalization procedure and statistical techniques, considering the use of physiological measures during the evaluation process. A case study comparison between two 3D interaction techniques (ray-casting and HOMER) shows promising results, pointing to heart rate variability, as measured by the NN50 parameter, as a potential index of task performance. Further studies are needed in order to establish guidelines for evaluation processes based on welldefined associations between human behaviors and human actions realized in 3D user interfaces.

A Virtual Environment for Drone Pilot Training Using VR Devices

This paper presents the development of a Virtual Reality environment for drone pilot training using interaction devices. We built an immersive interface in order to enhance the user experience in UAV training tasks comparing to the traditional control interfaces. To reach this aim, we chosen the Microsoft Kinect to control the drone and the Oculus Rift to visualize the scene, as well as keyboard, mouse and joystick support. As a result, we created a virtual environment in which users can train the drone pilot safely. Despite a good impression on preliminary tests, the solution still needs an evaluation by users and improvements in Physics simulations.

Using Petri Nets to specify collaborative three dimensional interaction

This work presents a methodology to formally model and to build collaborative three dimensional interaction tasks in virtual environments using three different tools: Petri Nets, Interaction Technique Decomposition taxonomy and Object-Oriented concepts. The user operations in the Virtual Environment are represented as Petri Net nodes and these nodes, when linked, represent the interaction process stages. The integration of these approaches results in a modular application, based on the Petri Nets formalism that allows for specification of collaborative interaction tasks, and also the reuse of developed blocks in new virtual environment projects.

Quality Assessment of Interaction Techniques in Immersive Virtual Environments Using Physiological Measures

This paper presents a new methodology for quality assessment of interaction techniques in immersive virtual environments, based on the study of the relationships between physiological measures and usability metrics using multivariate data analysis. Our methodology defines a testing protocol, a normalization procedure and statistical techniques, considering the use of physiological measures during the evaluation process. A case study comparison between two 3D interaction techniques (ray-casting and HOMER) shows promising results, pointing to heart rate variability, as measured by the NN50 parameter, as a potential index of task performance. Besides, this study also shows that heart rate (HR) and skin conductance (SC) measures reflect the users task performance during the interaction process. Despite these results, this work reveals that physiological measures still cannot be considered as substitutes of evaluation metrics for 3D interfaces, but may be useful in the interpretation and understanding process of them. Discussions also indicate the further studies are needed to establish guidelines for evaluation processes based on well-defined associations between human behaviors and human actions realized in 3D user interfaces.

Project and Preliminary Evaluation of VR-MED, a Domain-Specific Language for Serious Games in Family Medicine Teaching

Serious games can be used for training in different areas, like Education and Medicine. In these contexts, it is hard to define game-based learning environments, because this process requires intensive interaction between experts and developers in order to establish common, comprehensible and reusable elements for different projects by both professionals. A domain-specific language (DSL) tends to solve some modelling problems such as the creation and documentation of rules and the reuse of components. This paper presents VR-MED, a graphical DSL prototype for serious games, focused on teaching of Family Medicine. Using a visual notation, developers and healthcare professionals can create simple games based on textual medical cases. A preliminary study shows VR-MED as an adequate DSL to represent Family Medicine elements in a serious game, and that it can be extended to support new medical cases.