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Brain-controlled wheelchairs (BCWs) are a promising solution for people with severe motor disabilities, who cannot use conventional interfaces. However, the low reliability of electroencephalographic signal decoding and the high user's workload imposed by continuous control of a wheelchair requires effective approaches. In this paper, we propose a self-paced P300based brain-computer interface (BCI) combined with dynamic time-window commands and a collaborative-controller. The selfpaced approach allows users to switch between control and non-control states without requiring any additional task or mental strategy, while the dynamic time-window commands allow balancing the reliability and speed of the BCI. The collaborative controller, combining user's intentions and navigation information, offers the possibility to navigate in complex environments and to improve the overall system reliability. The feasibility of the proposed approach and the impact of each system component (self-paced, dynamic time-window and collaborative controller) were systematically validated in a set of experiments conducted with seven able-bodied participants and 6 physically disabled participants steering a robotic wheelchair in real office-like environments. These 2 groups controlled the BCW with a final driving accuracy greater than 99%. Quantitative and subjective results, assessed through questionnaires, attest to the effectiveness of the proposed approach. Altogether, these findings contribute to improve the usability of BCWs and hence the potential for their use by target users in home settings. Index Terms-Brain-computer interface (BCI), self-paced, dynamic time-window, collaborative control, robotic wheelchair, physically disabled, quantitative and subjective assessment.

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Remote monitoring of health parameters is a promising approach to improve the health condition and quality of life of particular groups of the population, which can also alleviate the current expenditure and demands of healthcare systems. The elderly, usually affected by chronic comorbidities, are a specific group of the population that can strongly benefit from telehealth technologies, allowing them to reach a more independent life, by living longer in their own homes. Usability of telehealth technologies and their acceptance by end-users are essential requirements for the success of telehealth implementation. Older people are resistant to new technologies or have difficulty in using them due to vision, hearing, sensory and cognition impairments. In this paper, we describe the implementation of an IoT-based telehealth solution designed specifically to address the elderly needs. The end-user interacts with a TV-set to record biometric parameters, and to receive warning and recommendations related to health and environmental sensor recordings. The familiarization of older people with the TV is expected to provide a more user-friendly interaction ensuring the effectiveness integration of the end-user in the overall telehealth solution.

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O objetivo deste trabalho é caracterizar as orações causais de enunciação num quadro teórico que postula a existência, no discurso, de distintos domínios da significação - domínio do conteúdo, domínio epistémico e domínio ilocutório-, na convicção de que uma análise semântica destas construções poderá contribuir para iluminar o seu comportamento sintático peculiar, que tanta controvérsia tem gerado. Defende-se, neste estudo, que as orações causais de enunciação expressam a relação discursiva de Justificação, que envolve sempre a articulação de dois atos ilocutórios, um deles com o estatuto de ato principal, o outro com o estatuto de ato subordinado. Num primeiro momento, analisa-se a articulação entre causais de enunciação e asserções e argumenta-se a favor da inseparabilidade entre os domínios epistémico e ilocutório neste tipo de construções, contrariamente ao que defende Sweetser (1999). Num segundo momento, analisa-se a articulação entre causais de enunciação e outras classes de atos ilocutórios, nomeadamente atos diretivos, compromissivos e expressivos.