2013
Autores
Jose, R; Rodrigues, H; Melro, A; Coelho, A; Ferreira, MC;
Publicação
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Abstract
The adoption of mobile payment systems is known to face multiple concerns regarding security, usability and value proposition. In this work, we start from the assumption that initial acceptance will always be weak because of the lack of an established usage frame. Instead, we focus on understanding how we can leverage upon the real contact with the technology to create a solid path for gradual acceptance through the development of new practices and the increasing perception of value. In this study, we report on our findings with a real-world prototype of a NFC-based payment system. We identify a set of design lessons that may help to improve the initial phases of NFC-based payment deployments and provide a path for the adoption that focuses on positive initial user experiences and early adoption scenarios. © Springer International Publishing 2013.
2013
Autores
Fernandes, H; Faria, J; Martins, P; Paredes, H; Barroso, J;
Publicação
HCI (5)
Abstract
People with visual impairments face serious challenges while moving from one place to another. This is a difficult challenge that involves obstacle avoidance, staying on street walks, finding doors, knowing the current location and keeping on track through the desired course, until the destination is reached. While assistive technology has contributed to the improvement of the quality of life of people with disabilities, people with visual impairment still face enormous limitations in terms of their mobility. There is still an enormous lack of availability of information that can be used to assist them, as well as a lack of sufficient precision in terms of the estimation of the user's location. This paper proposes an infrastructure to assist the estimation of the user's location with high precision using Radio Frequency Identification, providing seamless availability of location based services for the blind, whether indoor or outdoor. © 2013 Springer-Verlag.
2013
Autores
Duarte, IC; Cunha, G; Castelhano, J; Sales, F; Reis, A; Silva Cunha, JPS; Castelo Branco, M;
Publicação
BRAIN AND COGNITION
Abstract
Localized neurodevelopmental defects provide an opportunity to study structure-function correlations in the human nervous system. This unique multimodal case report of epileptogenic dysplasia in the visual cortex allowed exploring visual function across distinct pathways in retinotopic regions and the dorsal stream, in relation to fMRI retinotopic mapping and spike triggered BOLD responses. Pre-surgical EEG/video monitoring, MRI/DTI, EEG/fMRI, PET and SPECT were performed to characterize structure/function correlations in this patient with a very early lesion onset. In addition, we included psychophysical methods (assessing parvo/konio and magnocellular pathways) and retinotopic mapping. We could identify dorsal stream impairment (with extended contrast sensitivity deficits within the input magno system contrasting with more confined parvocellular deficits) with disrupted active visual field input representations in regions neighboring the lesion. Simultaneous EEG/fMRI identified perilesional and retinotopic bilaterally symmetric BOLD deactivation triggered by interictal spikes, which matched the contralateral spread of magnocellular dysfunction revealed in the psychophysical tests. Topographic changes in retinotopic organization further suggested long term functional effects of abnormal electrical discharges during brain development. We conclude that fMRI based visual field cortical mapping shows evidence for retinotopic dissociation between magno and parvocellular function well beyond striate cortex, identifiable in high level dorsal visual representations around visual area V3A which is consistent with the effects of epileptic spike triggered negative BOLD.
2013
Autores
Cardoso, JMP; De F. Coutinho, JG; Carvalho, T; Diniz, PC;
Publicação
Compilation and Synthesis for Embedded Reconfigurable Systems: An Aspect-Oriented Approach
Abstract
This chapter presents LARA, an aspect-oriented domain-specific language developed in the context of the REFLECT project. We describe its main features, including syntax and semantics (as defined by the LARA 2.0 technical specification [1]), and provide detailed examples of its use. In particular, we cover the mapping of computations written in high-level programming languages such as C to reconfigurable architectures considering non-functional requirements and user concerns. © Springer Science+Business Media New York 2013. All rights are reserved.
2013
Autores
Sousa, RG; Garcia, PJV; Marinho, V; Mouraz, A;
Publicação
2013 1ST INTERNATIONAL CONFERENCE OF THE PORTUGUESE SOCIETY FOR ENGINEERING EDUCATION (CISPEE)
Abstract
The electromagnetic theory presents a unifying explanation of electric and magnetic phenomena underlying our technological society. It is a fundamental physical theory taught in engineering schools at university level. In this theory the electromagnetic field is a vector field permeating space. An important aspect relating to students difficulties and misconceptions is the difficulty in visualizing vector fields. With the goal of enhancing student understanding and studying student engagement we have developed high quality 3D visualizations of electromagnetic situations. These make use of accurate computation of the field lines, together with realistic rendering using the open source software Blender. We present examples of electrostatic situations with both an assessment of the student understanding and an evaluation of the students' perceptions of the importance of the visualizations. Complex interplay between visualization specific issues and the abstract notion of the field is identified in the students' conceptions. It is found that the visualizations are not used as substitutes of other learning resources. They are perceived as allowing a quick access to content and prompting motivation. The adequacy of the visualization to the subject content as well as the capacity to use it as self-assessment is valued by the students.
2013
Autores
Pereira, T; Oliveira, T; Cabeleira, M; Pereira, H; Almeida, V; Cardoso, J; Correia, C;
Publicação
IEEE SENSORS JOURNAL
Abstract
New optical probes are developed for carotid distention waveform measurements, in order to assess the risk of cardiovascular diseases. The probes make use of two distinct photodetectors: planar and avalanche photodiodes. Their performance is compared for visible and infrared (IR) light wavelengths. The test setup designed for the evaluation of the probes simulates the fatty deposits commonly seen in the obese people, between skin and the artery. The performed tests show that the attenuation of the signal is lower for the IR light, with higher penetration and better resolution in the captured distension waveform, with higher definition in morphological features on the wave and higher signal-to-noise ratio when compared to the visible source signals. The probes show good overall performance in the test setup with a root mean square error lower than 8%. In vivo, the IR probes allow easier waveform detection, even more relevant with the increasing deposit structures.
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