Abstract
User experience can be affected by the amount and intensity of information presented. Four scenarios were developed to assess the insertion of information elements (chronometer and hint system) and tested with 37 users to find out if they affected the user's sense of presence and symptoms of cybersickness. In order to instruct users and using virtual reality using the Unity 3D game engine, we created a virtual world where the user has the role of exploring the environment and looking for mushrooms, and can consult a description about it. For tests with users, the IPQp and SSQ questionnaires were applied. The results indicate that it is possible to create a virtual world with the addition of informational components without significantly disturbing the user experience.

Abstract
Construction and analysis of distributed systems is difficult. Multiparty session types (MPST) constitute a method to make it easier. The idea is to use type checking to statically prove deadlock freedom and protocol compliance of communicating processes. In practice, the premier approach to apply the MPST method in combination with mainstream programming languages has been based on API generation. In this paper (pearl), we revisit and revise this approach. Regarding our “revisitation”, using Scala 3, we present the existing API generation approach, which is based on deterministic finite automata (DFA), in terms of both the existing states-as-classes encoding of DFAs as APIs, and a new states-as-type-parameters encoding; the latter leverages match types in Scala 3. Regarding our “revision”, also using Scala 3, we present a new API generation approach that is based on sets of pomsets instead of DFAs; it crucially leverages match types, too. Our fresh perspective allows us to avoid two forms of combinatorial explosion resulting from implementing concurrent subprotocols in the DFA-based approach. We implement our approach in a new API generation tool.

Abstract
This article focuses on a sensorial glove prototype capable of acquiring hand motion and estimating its pose. The presented solution features twelve inertial measurement units (IMUs) to track hand orientation. The sensors are attached to a glove to decrease the project cost. The system also focuses on sensor fusion algorithms for the IMUs and further implementations, presenting the algebraic quaternion algorithm (AQUA), used because of its modularity and intuitive implementation. An adaptation of a human hand model is proposed, explaining its advantages and its limitations. Considering that the calibration is a very important process in gyroscope performance, the online and offline calibration data was analyzed, pointing out its challenges and improvements. To better visualize the model and sensors a simulation was conducted in Unity.

Abstract
A piston type projector using the PVDF piezoelectric polymer was developed for operating in underwater environment, below 100 kHz. For those frequencies PZT piezoelectric ceramic is usually a preferable choice and PVDF is only considered for frequencies above a few hundreds of kHz. This paper will show that efficient underwater acoustic projectors for frequencies below 100 kHz can be implemented regarding an appropriate impedance adapter is being used. The developed project presents a calibrated transmitting voltage response (TVR) of approximately 166, 160 and 175 dB at 40, 50 and 75 kHz, respectively. The PVDF TVR values are compatible with the PZT projectors available on market with the advantage of having a larger bandwidth than most PZT projectors. To the authors knowledge this is the first time that a PVDF projector attain such characteristics. Although theoretically the PVDF projector bandwidth is larger than 40 to 80 kHz, in practice it was observed that only between those frequencies the project presents a stable operation for the transmission of long-term signals.

Abstract

Abstract
Chairing online Master Programmes requires constant monitoring and decision-making, amidst diversified data and ongoing processes. If misunderstood or misinterpreted, poor decisions may result, as well as lost opportunities to support enrolled students. Decision-making can be supported by dashboards, but there are few prototypes which underwent limited evaluation. We focus on identifying and prototyping efficient visualisation and interaction methods for such a dashboard, to offer online Master Program chairs opportunities for better analysis and decision-making. Design science research was conducted: evaluate and revise an existing prototype; evaluate the revised prototype with master program chairs; design, implementation, and evaluation of a final prototype, again involving master program chairs. The final prototype dashboard provides a way for Master Program chairs to visualize and interact with Master Program data, to support improved analysis of information and quick identification of problems, towards better decision-making.;A coordenação de cursos de mestrado online requer constante acompanhamento e tomada de decisões, com dados diversificados e processos em curso. Se mal interpretados, podem advir decisões inadequadas ou perderem-se oportunidades de apoiar os alunos do curso. Existem painéis de instrumentos de apoio, mas poucos protótipos, carentes de avaliação aprofundada. Focámo-nos na identificação e prototipagem de métodos de visualização e interação para um destes painéis, visando proporcionar aos coordenadores de cursos de mestrado online oportunidades para melhor tomada de decisão. Conduzimos iterações de investigação por ciência da conceção: avaliação e reformulação de protótipo existente; avaliação do protótipo revisto por coordenadores de cursos de mestrado; conceção, implementação e avaliação de protótipo final, novamente envolvendo coordenadores de cursos. O protótipo final constitui uma forma de coordenadores de curso visualizarem e interagirem com os dados do curso, apoiando melhor análise e rápida identificação de problemas, visando melhor tomada de decisões.