Luís Correia

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  • Fernando Miguel Pais, Graça Lobo, +39 authors Donna Eiskamp
  • 2000
Genetic algorithms (GAs) have been used to solve difficult optimization problems in a number of fields. One of the advantages of these algorithms is that they operate well even in domains where little is known, thus giving the GA the flavor of a general purpose problem solver. However, in order to solve a problem with the GA, the user usually has to specify(More)
An increased fetal nuchal translucency detected by first trimester ultrasound has been associated with an elevated risk of aneuploidy. The etiology of the increased nuchal translucency in fetuses with normal chromosomes is uncertain, but it has been associated with poor pregnancy outcome. We report a fetus with increased nuchal translucency and a normal(More)
We analyze the influence of the update dynamics on symmetric 2-player evolutionary games, which are among the most used tools to study the emergence of cooperation in populations of interacting agents. A synchronous dynamics means that, at each time step, all the agents of the population update their strategies simultaneously. An extreme case of(More)
This paper describes a vehicle to perform a simple task using a decision control composed of a behavior hierarchy. First the model is presented. It is based on two fundamental components: the behavior module defining how each behavior element is implemented; and the blocker which is the basic component of the arbitration system, responsible for behavior(More)
The unstructured nature of cross-country environments poses a great deal of challenges to obstacle detection algorithms. This paper presents an algorithm able to perform obstacle detection with small computational cycles, and extremely robust against outliers. To reduce the computational cost, foveation, i.e. space-variant image resolution adaptation, is(More)
This paper proposes a model for trail detection and tracking that builds upon the observation that trails are salient structures in the robot’s visual field. Due to the complexity of natural environments, the straightforward application of bottom-up visual saliency models is not sufficiently robust to predict the location of trails. As for other detection(More)
This article presents a constraint-based behavioural architecture for low-level safe navigation, the Survival Kit. Instead of approaching the problem by customising a generic Behaviour-Based architecture, the Survival Kit embodies a dedicated semantics for safe navigation, which augments its expressiveness for the task. An instantiation of the architecture(More)
BACKGROUND Ulcerative colitis (UC) has a large impact on patients' lives. Clinical course studies of population-based cohorts contribute to our understanding of the disease as it progresses. We reviewed the clinical course of UC as reported in adult population-based longitudinal cohort studies. METHODS A MEDLINE literature search to identify all adult(More)