ESTG - Comunicações em conferências e congressos internacionais
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- State of the art of accessible development for smart devices: From a disable and not impaired point of viewPublication . Silva, João de Sousa e; Pereira, António; Gonçalves, Ramiro; Gomes, SílviaThe need and benefits of digital accessibility are evident and, with the current ubiquitous trends, the profits are hugely potentiated. However, the fast evolution is instigating some issues in this area's accessibility. To understand the conceivable impact of these issues' tenacity in society, general accessibility features are explained as a reasonable application for all parties. Nevertheless, the potential of ubiquitous computation in order to promote social integration of citizens with impairments is focused and elucidated. The benefits of applying so much effort on accessibility as well as on usability is asserted and related to universal design. Hence, in order to promote a more universal applications development, the mobile operating systems available in the market, which are more plausible to be chosen and used by people with impairments, are scrutinized and shown from a standpoint of a developer that has accessibility and usability concerns. The paper leads to the conclusions that ubiquitous computation may have power to nullify impairments but, to be assistive, several issues regarding the devices and the operating system that runs on them have to be taken in mind and considered.
- Database synchronization model for mobile devicesPublication . Domingos, João; Simões, Nuno; Pereira, Paulo; Silva, Catarina; Marcelino, LuisWith the increasing number of mobile devices it is necessary to create adapted solutions for this type of devices that respect their limited processing capacities, memory and bandwidth. We propose a synchronization model based on message digests to synchronize relational databases between mobile devices and a server, in order to minimize the data transferred between the device and the server and to minimize the processing done by the mobile device. The approach consists in a synchronization model where the amount of data to be exchanged has been reduced to the minimum. In order to achieve the model above a registry is done in the device with the new, the modified or removed content, which purpose is to send only the essential data for synchronization from the device to the server. Regarding the synchronization from the server to the device, the modifications are calculated and sent to the device. This model is independent of proprietary solutions and can be adapted to any system or platform, often involving software development to the mobile application and the application server. The results of testing the model show that the proposed model can achieve better synchronization times than the competitor models, while always fulfilling the set objectives.
- Patinhas Serviços de localização para animais desaparecidosPublication . Guerra, André; Tereso, Bruno; Brites, José; Silva, Catarina; Marcelino, LuisResumo — Todos os dias e por todo o lado existem animais que se perdem ou que são encontrados. Para grande parte destes casos existe uma dificuldade acrescida, não só em encontrar o dono do animal, mas também em reunir os esforços de inúmeros voluntários que, de uma forma ou outra, pretendem ajudar. De forma facilitar a procura de animais perdidos, foi proposto disponibilizar uma aplicação móvel em iOS, que permite a um utilizador colocar anúncios sobre animais perdidos e/ou encontrados, com base na localização onde foram vistos pela última vez. A aplicação serve igualmente de apoio à busca do animal. Sendo este um serviço que foca principalmente o senso comum e o espírito de entreajuda, torna-se importante notificar o utilizador no seu dia a dia, em situações em que ele pode ser verdadeiramente útil sem prejudicar, por exemplo, o seu itinerário. Por isso, foi criado um sistema de alertas que avisa o utilizador, ao passar numa determinada rua, quais os anúncios atuais na sua proximidade.
- eFSLab: Developing evolving fuzzy systems from data in a friendly environmentPublication . Dourado, Antonio; Aires, Lara; Ramos, J. VictorA software lab is presented to support the development of fuzzy systems from data (data-driven approach) avoiding redundancy and unnecessary complexity in the obtained membership functions, in order to give some semantic meaning to the results. On-line mechanisms for merging membership functions and rule base simplification are implemented improving interpretability and transparency of the produced fuzzy models, allowing the minimization of redundancy and complexity of the models during their development, contributing to the transparency of the obtained rules. The application, developed in Matlab environment, and public under GNU license, is applied to one benchmark problem- the Box-Jenkins time series prediction- with illustrative results.
- Concept Drift Awareness in Twitter StreamsPublication . Costa, Joana; Silva, Catarina; Antunes, Mario; Ribeiro, BernardeteLearning in non-stationary environments is not an easy task and requires a distinctive approach. The learning model must not only have the ability to continuously learn, but also the ability to acquired new concepts and forget the old ones. Additionally, given the significant importance that social networks gained as information networks, there is an evergrowing interest in the extraction of complex information used for trend detection, promoting services or market sensing. This dynamic nature tends to limit the performance of traditional static learning models and dynamic learning strategies must be put forward. In this paper we present a learning strategy to learn with drift in the occurrence of concepts in Twitter. We propose three different models: a time-window model, an ensemble-based model and an incremental model. Since little is known about the types of drift that can occur in Twitter, we simulate different types of drift by artificially timestamping real Twitter messages in order to evaluate and validate our strategy. Results are so far encouraging regarding learning in the presence of drift, along with classifying messages in Twitter streams.
- Integrating a Head-mounted Display with a Mobile Device for Real-time Augmented Reality PurposesPublication . Madeira, Bruno; Alves, Pedro; Marto, Anabela; Rodrigues, Nuno; Gonçalves, AlexandrinoFollowing the current technological growth and subsequent needs felt by industries, new processes should be adopted to make tasks simpler. Using Augmented Reality in conjunction with other technologies, it is possible to develop innovative solutions that aim to alleviate the difficulty of certain processes in the industry, or to reduce the time of their execution. This article addresses one of the possible applications of new technologies in the industry, using devices that allow the use of Augmented Reality without requiring much or no physical interaction by workers or causing many distractions, thus giving relevant information to the work to be performed without interfering with the quality of it. It will focus, more precisely, on integrating the Head-Mounted Display Moverio BT-35E with a mobile device and in describing the needed configurations for preparing this device to show information to warehouse operators, using Augmented Reality, provided by a software that runs on a capable device, discussing also what are the main mishaps discovered with the use of this device.
- The regression analysis of the data to determine the buffer size when serving a self-similar packets flowPublication . Linets, Gennadiy; Voronkin, Roman; Govorova, Svetlana; Palkanov, Ilya; Grilo, CarlosUsing the methods of regression analysis on the basis of simulation data, a model for predicting the queue size of the input self-similar packet flow, distributed according to the Pareto law when it is transformed into a flow having an exponential distribution, is constructed. Since the amount of losses in the general case does not give any information about the efficiency of using the buffer memory space in the process of transforming a self-similar packet flow, a quality metric (penalty) was introduced to get the quality of the models after training, which is a complex score. This criterion considers both packet loss during functional transformations and ineffective use of the buffer space in switching nodes. The choice of the best model for predicting the queue size when servicing a self-similar packet flow was carried out using the following characteristics: the coefficient of determination; root-mean-square regression error; mean absolute error; the penalty score. The best in terms of the investigated characteristics are the models using the isotonic regression and the support vector regression.
- No-reference lightweight estimation of 3D video objective qualityPublication . Soares, João R. S.; Cruz, Luis A. da Silva; Assunção, Pedro; Marinheiro, RuiA no-reference (NR) method based on an artificial neural network (ANN) approach is proposed in this paper to estimate the objective quality of video-plus-depth streams subject to packet loss in depth data. A novel aspect of this method is the use of information only taken from packet headers, up to the network abstraction layer (NAL), requiring a very low complexity parsing of the compressed video streams. A maximum of seven packet-layer parameters were found to be enough to provide accurate objective quality estimates given by the structural similarity index (SSIM). The accuracy of the quality estimates, evaluated by comparison with the actual SSIM quality scores, is shown to be sufficiently high (e.g., Pearson Linear Correlation Coefficient over 0.92) for lightweight implementations of 3D video quality monitors at end-user receivers and also at network nodes.
- Selective motion vector redundancies for improved error resilience in HEVCPublication . Carreira, J.; Ekmekcioglu, E; Kondoz, A.; Assuncao, P.; Faria, S.; Silva, V. DeThis paper addresses the problem caused by motion vector coding dependencies on the error resilience performance of the emergent High Efficiency Video Coding (HEVC) standard. We propose a method based on the prediction dependency of motion vectors (MV) to select the most relevant ones for redundant coding with reduced overhead. The spatial dependencies are analysed in the encoder to prioritise the MVs that should be selected for redundancy, based on the number of subsequent dependent coding units. Then, a subset of prioritised MVs is transmitted as redundancy (referred to as side information in the paper), to reduce the use and propagation of mismatched MV predictions in case of transmission errors or data loss. The simulation results show that the proposed MV selection method can effectively identify the most relevant motion field, achieving improved error robustness with a reduced redundancy overhead. Exploiting only 30% of the generated MVs for redundancy, average quality gains of up to 1 dB are achieved compared to a uniform MV selection scheme, and up to 2 dB compared to the original HEVC standard with no redundant encoded information.
- Characterization of polymer behaviour in microchannelsPublication . Costa, M.; Vasco, J.; Pouzada, A. S.; Pontes, A. J.Microinjection moulding can be used to process monitoring and rheological characterization can help to understand the behavior of polymer melt flows during the filing of micro cavities. The system used allows a study on characterization of polymer behavior in microchannels. This approach is appropriate since rheological phenomena such as wall slip, surface tension, melt pressure drop and polymer flow length can be studied. In this system, the data acquisition has made by incorporation of two sensors inside the mould.