2013
Authors
Gonçalves, J; Lima, J; Costa, PJ; Moreira, AP;
Publication
Lecture Notes in Mechanical Engineering
Abstract
This paper describes the EMG30 mechanical and electrical modeling and its simulation resorting to SimTwo (Robot@Factory mobile robot competition official simulator). It is described the developed setup applied to obtain the experimental data that was used to estimate the actuator parameters. It was obtained an electro-mechanical dynamical model that describes the motor, its gear box, and the encoder. The motivation to model and simulate the EMG30 is the fact that it is an actuator worldwide popular in the mobile robotics domain, being a low cost 12v motor equipped with encoders and a 30:1 reduction gearbox. The Goal of this work is to provide more realism and new features to the Robot@Factory official simulator, allowing participating teams to produce and validate different robot prototypes and its software, reducing considerably the development time. © Springer International Publishing Switzerland 2013.
2013
Authors
Ana Isabel Perdigão Lopes Pereira Torres;
Publication
Abstract
2013
Authors
Loureiro, T; Camacho, R; Vieira, J; Fonseca, NA;
Publication
J. Integr. Bioinform.
Abstract
Transposable Elements (TE) are sequences of DNA that move and transpose within a genome. TEs, as mutation agents, are quite important for their role in both genome alteration diseases and on species evolution. Several tools have been developed to discover and annotate TEs but no single tool achieves good results on all different types of TEs. In this paper we evaluate the performance of several TEs detection and annotation tools and investigate if Machine Learning techniques can be used to improve their overall detection accuracy. The results of an in silico evaluation of TEs detection and annotation tools indicate that their performance can be improved by using machine learning constructed classifiers.
2013
Authors
Oliveira, M; Gama, J;
Publication
EXPERT SYSTEMS
Abstract
Visualization of static social networks is a mature research field in information visualization. Conventional approaches rely on node-link diagrams that provide a representation of the network topology by representing nodes as points and links between them as lines. However, the increasing availability of longitudinal network data has spurred interest in visualization techniques that go beyond the static node-link representation of a network. In temporal settings, the focus is on the network dynamics at different levels of analysis (e.g. node, communities and whole network). Yet, the development of visualizations that are able to provide actionable insights into different types of changes occurring in the network and their impact on both the neighbourhood and the overall network structure is a challenging task. In such settings, traditional node-link representations can prove to be limited (Yi et al., 2010). Alternative methods, such as matrix graph representations, fail in tasks involving path finding (Ghoniem et al., 2005). This work attempts to overcome these issues by proposing a methodology for tracking the evolution of dynamic social networks, at both the node-level and the community-level, based on the concept of temporal trajectory. We resort to three-order tensors to represent evolving social networks, and we further decompose them using a Tucker3 model. The two most representative components of this model define the 2D space where the trajectories of social entities are projected. To illustrate the proposed methodology, we conduct a case study using a set of temporal self-reported friendship networks.
2013
Authors
Sousa, JJ; Bastos, L;
Publication
NATURAL HAZARDS AND EARTH SYSTEM SCIENCES
Abstract
On the night of 4 March 2001, at Entre-os-Rios (Northern Portugal), the Hintze Ribeiro centennial bridge collapsed killing 59 people traveling in a bus and three cars that were crossing the Douro River. According to the national authorities, the collapse was due to two decades of uncontrolled sand extraction which compromised the stability of the bridge's pillars, together with underestimating the warnings from divers and technicians. In this work we do not intend to corroborate or contradict the official version of the accident's causes, but only demonstrate the potential of Multi-Temporal Interferometric techniques for detection and monitoring of deformations in structures such as bridges, and consequently the usefulness of the derived information in some type of early warning system to help prevent new catastrophic events. Based on the analysis of 52 ERS-1/2 covering the period from May 1995 to the fatal occurrence, we were able to detect significant movements, reaching rates of 20mmyr-1, in the section of the bridge that fell into the Douro River, which are obvious signs of the bridge's instability. These promising results demonstrate that with the new high-resolution synthetic aperture radar satellite scenes it is possible to develop interferometric based methodologies for structural health monitoring.
2013
Authors
Soares, Tiago; Santos, Gabriel; Faria, Pedro; Ppinto, Tiago; Vale, Zita; Morais, Hugo;
Publication
ISAP 2013 - 17th International Conference on Intelligent System Applications to Power Systems
Abstract
The provision of reserves in power systems is of great
importance in what concerns keeping an adequate and
acceptable level of security and reliability. This need for reserves
and the way they are defined and dispatched gain increasing
importance in the present and future context of smart grids and
electricity markets due to their inherent competitive environment.
This paper concerns a methodology proposed by the
authors, which aims to jointly and optimally dispatch both
generation and demand response resources to provide the
amounts of reserve required for the system operation. Virtual
Power Players are especially important for the aggregation of
small size demand response and generation resources. The
proposed methodology has been implemented in MASCEM, a
multi agent system also developed at the authors’ research
center for the simulation of electricity markets.
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