2015
Autores
Pimenta, A; Carneiro, D; Novais, P; Neves, J;
Publicação
Ambient Intelligence - Software and Applications - 6th International Symposium on Ambient Intelligence, ISAmI 2015, Salamanca, Spain, June 3-5, 2015.
Abstract
In our busy daily life, we often have the feeling of being exhausted, accompanied with a sense of performance degradation and increase of discomfort in the execution of even simple tasks. This often takes place in the workplace and in a silent way, influencing our productivity, our performance the number of errors or the quality of our production. This paper details a chair to be used in workplace environments that is sensitive to the onset of fatigue. Based on built-in accelerometers it recognizes signs of discomfort, which may be related to mental fatigue, to point out moments when an individual should consider taking a pause or a rest. This chair complements a previously developed software for the assessment of mental fatigue from the analysis of the individual's interaction with the computer. © Springer International Publishing Switzerland 2015.
2015
Autores
Goncalves, S; Rodrigues, M; Carneiro, D; Fdez Riverola, F; Novais, P;
Publicação
METHODOLOGIES AND INTELLIGENT SYSTEMS FOR TECHNOLOGY ENHANCED LEARNING
Abstract
Keeping students interested and motivated is perhaps one of the most difficult and traditional tasks assigned to teachers. With technology being engaged increasingly into learning activities, with its advantages and disadvantages, some new aspects need to be considered. Undoubtedly, technology acts as an enhancer for learning, opening new paths for teaching. However there are some drawbacks too. Keeping students in the right track, doing what they are expected to do, with commitment and motivation, becomes an enormous challenge when an amazing digital world full of all kind of temptations is at the distance of their personal smartphones or even in the computer they use to study. This excess of stimuli and the process of switching and choosing between them has as potential effects on attention, stress and mental fatigue. Stressed or fatigued students fail to deliver the required performance for the task they are engaged in. This paper presents a non-intrusive approach for monitoring student's performance in real time and measure the effect of these external variables on students. The long-term goal is to empower teachers with valuable information about the students' state, allowing them to better manage their students and teaching methodologies.
2015
Autores
Gomes, R; de Sousa, JP; Dias, TG;
Publicação
RESEARCH IN TRANSPORTATION ECONOMICS
Abstract
In a time of economic austerity, more pressure is being put on the existing transport systems to be more sustainable and, at the same time, more equitable and socially inclusive. Regular public road transportation traditionally uses fixed routes and schedules, which can be extremely expensive in rural areas and certain periods of the day in urban areas due to low and unpredictable demand. Demand Responsive Transportation systems are a kind of hybrid transportation approach between a taxi and a bus that try to address these problems with routes and frequencies that may vary according to the actual observed demand. Demand Responsive Transportation seems to have potential to answer the sustainability and social inclusion challenges in a context of austerity. However, DRT projects may fail: it is not only important to solve the underlying model in an efficient way, but also to understand how different ways of operating the service affect customers and operators. To help design DRT services, we developed an innovative approach integrating simulation and optimization. Using this simulator, we compared a real night-time bus service in the city of Porto, Portugal, with a hypothetical flexible DRT service for the same scenario.
2015
Autores
Silva, P; Antunes, F; Gomes, R; Bento, C;
Publicação
PROGRESS IN ARTIFICIAL INTELLIGENCE
Abstract
Traditionally, travel demand modelling focused on long-term multiple socio-economic scenarios and land-use configurations to estimate the required transport supply. However, the limited number of transportation requests in demand-responsive flexible transport systems require a higher resolution zoning. This work analyses users short-term destination choice patterns, with a careful analysis of the available data coming from various different sources, such as GPS traces and social networks. We use a Multinomial Logit Model, with a social component for utility and characteristics, both derived from Social Network Analyses. The results from the model show meaningful relationships between distance and attractiveness for all the different alternatives, with the variable distance being the most significant.
2015
Autores
Barros, PD; Baptista, AJ; Alves, JL; Oliveira, MC; Rodrigues, DM; Menezes, LF;
Publicação
ENGINEERING WITH COMPUTERS
Abstract
Over the last years, the numerical simulation of integrated processes has become the major challenge in virtual try-out of sheet metal components, including trimming operations that may occur between forming steps. Detailed simulation of trimming processes is a challenging task, particularly when integrated with other forming operations such as deep drawing or hemming. A simplified approach can be adopted in which elements outside the trim surface are deleted from the finite element (FE) model adjusting the remaining to the surface. Following this approach, the state variables are mapped from the old FE mesh to the new trimmed mesh to continue the simulation. This paper addresses this simplified approach to the trimming process exploring a previously presented algorithm (Finite Elem Anal Des 42: 1053-1060, Baptista et al. 2006), which allows the treatment of hexahedral finite element meshes. Particularly, it focuses on the performance evaluation of the implemented strategies for correcting the FE mesh to the trimming surface, including the treatment of pentahedral-shaped elements. Different correction and treatment strategies are evaluated on different types of meshes, based on numerical simulation results of simple mechanical tests: uniaxial tensile test and simple bending test. Finally, two practical applications are given where the local effect of the trimming algorithm is highlighted.
2014
Autores
Oliveira, RC; Ferreira, JS;
Publicação
Abstract
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