Browsing by Author "Ferreira, Carlos"
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- Arduino based Open Source Electronic Control Unit for Electric Utility VehiclesPublication . Francisco, Alexandre; Lopes, Nuno Vieira; Conde Bento, Luis; Ferreira, CarlosThis paper presents the design and development of a low-cost Electronic Control Unit (ECU), aimed for the application and control of Electric Utility Vehicles (EUV). The selection of components and features, as well the design and project of all the necessary hardware, was also carried out. The major features that overcome other available solutions are: multiple Controller Area Network (CAN) buses, electrical isolation of inputs, outputs, two CAN buses and serial interface, outputs with current feedback and its reduced overall cost. Validation tests were conducted in order to verify all functionalities. Moreover, an electric vehicle simulator was developed to assess the performance of the ECU in a real world working environment. The fully functional prototype of the ECU proved to be robust and experimental results fulfill the proposed objectives.
- Determinantes do acesso ao serviço de urgência por utentes não urgentesPublication . Dixe, Maria dos Anjos; Passadouro, Rui; Peralta, Teresa; Ferreira, Carlos; Lourenço, Georgina; Sousa, PedroEnquadramento: A utilização dos serviços de urgência (SU) por situações não urgentes constitui uma preocupação a nível nacional e mundial. Objetivos: Avaliar as características sociodemográficas e o acesso ao SU por utentes não urgentes e identificar os fatores que motivam a sua procura. Metodologia: Neste estudo transversal recorreu-se a uma entrevista e à consulta dos processos clínicos eletrónicos de 357 doentes triados como não urgentes num SU de um hospital português seguindo-se uma amostragem acidental. Resultados: Os utentes da amostra são maioritariamente do sexo feminino, de meia-idade, com reduzidas habilitações literárias, que recorrem ao SU, sobretudo no período diurno e por iniciativa própria. Os motivos mais referenciados foram: A minha doença justifica a ida à urgência (91,7%) e Posso realizar os exames todos no mesmo dia (65,6%). A maioria dos utentes (87,9%) teve alta clínica, sendo que 84,9% dos utentes tem acesso ao médico de família. Conclusão: Foram identificados múltiplos determinantes do acesso ao SU, permitindo apontar sugestões que visam uma utilização racional dos cuidados de saúde.
- Determinants of non-urgent emergency department usePublication . Dixe, Maria dos Anjos; Passadouro, Rui; Peralta, Teresa; Ferreira, Carlos; Lourenço, Georgina; Sousa, Pedro Miguel LopesBackground: The use of the emergency department (ED) for non-urgent situations is a source of concern, both at the national and international levels. Objectives: To assess the sociodemographic characteristics and ED use of non-urgent patients and to identify the reasons for non-urgent ED use. Methodology: This cross-sectional study used patient interviews and the electronic medical records of 357 patients triaged as non-urgent at a Portuguese hospital ED, using an accidental sampling technique. Results: The majority of patients were women, middle-aged, and had a low education level; most of them used the ED during the day and on their own initiative. The most common reasons were: My disease justifies ED use (91.7%) and I can undergo all medical examinations on the same day (65.6%). The majority of patients (87.9%) were discharged, and 84.9% had access to a family doctor. Conclusion: Multiple determinants of non-urgent ED use were identified. Some recommendations were put forward to improve the rational use of healthcare services.
- Development of a distributed electronic system for low-cost heavy-duty engine test benchPublication . Rodrigues Gouveia, Olivier; Borges, Alexandre; Costa, Diogo; Coelho, Diogo; Lopes, Paulo; Perpétua, Hugo; Serrano, Luis; Ferreira, CarlosTest benches are important tools for the optimization and diagnosis of internal combustion engines. This paper presents the work done to develop a low-cost tech bench for heavy-duty engines, which uses an electromagnetic brake, to apply load to the engine, and a distributed electronic system for control and data acquisition. Signal noise contamination in test benches represents a problematic aspect of the engine testing. Moreover, a distributed control and monitoring electronic systems, allied with a Controller Area Network (CAN) communication bus for signal transmission, was used to mitigate and ultimately immunize signals from noise sources such as electric or electromagnetic fields. Overall, a heavy-duty test bench aiming the engines diagnostics was obtained, where all control and data acquisition is performed via an USB serial port, interfacing with two CAN bus networks, in a complete distributed control system.
- Optimized Design of a Piezoresistive Pressure Sensor with Measurement Span of 1MPaPublication . Ferreira, Carlos; Grinde, C.; Morais, R.; Valente, A.; Neves, C.; Reis, M.This paper presents a piezoresistive pressure sensor with a measurement span of 1MPa and capable to withstand peak pressures around 10MPa. The sensor design, based on a square membrane, was optimized for enhanced sensitivity, high linearity and low sensitivity variations between fabricated samples. Being the asymmetry of the mechanical stress peaks, the ratio between the membrane area and its thickness, and the tolerances of the bulk micromachining process considered for the optimal positioning of the piezoresistive sensing elements. Practical results show a mean sensitivity of 30.9mV/V/MPa with a standard deviation of 0.65mV/V/MPa and a linearity error of 0.15% of the scale span.
- Promoting social network awareness: A social network monitoring systemPublication . Cadima, Rita; Ferreira, Carlos; Monguet, Josep; Ojeda, Jordi; Fernandez, JoaquinTo increase communication and collaboration opportunities, members of a community must be aware of the social networks that exist within that community. This paper describes a social network monitoring system - the KIWI system - that enables users to register their interactions and visualize their social networks. The system was implemented in a distributed research community and the results have shown that KIWI facilitates collecting information about social interactions. Furthermore, the visualization of the social networks, given as feedback, appeared to have a positive impact on the group, augmenting their social network awareness.