Léo Pini Magalhães

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This paper presents a method for crowd simulation based on a biologically-motivated space colonization algorithm. This algorithm was originally introduced to model leaf venation patterns and the branching architecture of trees. It operates by simulating the competition for space between growing veins or branches. Adapted to crowd modeling, the space(More)
The Coordination of interdependencies between tasks in collaborative environments is a very important and difJicult endeavor. The separation between tasks and interdependencies allows f o r the use of different coordination policies in the same collaborative environment by changing only the coordination mechanisms that control the interdependencies. This(More)
The coordination of cooperative workflows is a problem that occurs in parallel to that of the definition of a common communications infrastructure among organizations. In this paper, we present a library of coordination mechanisms modeled with Petri Nets. These mechanisms specify and control the interaction between workflow processes. The separation between(More)
In content-based image retrieval (CBIR) using feedback-based learning, the user marks the relevance of returned images and the system learns how to return more relevant images in a next iteration. In this learning process, image comparison may be based on distinct distance spaces due to multiple visual content representations. This work improves the(More)
 The configuration of theoretical courses complemented by "hands on" laboratories has been shown effective to internalize theory, give concrete context and enhance skills. However, learning the "hands on" tools dispenses usually unaffordable time; that is particularly true for computer programming, since the amount of programming language taught during(More)
This paper presents a novel approach for the generation of realistic speech synchronized 3D facial animation that copes with anticipatory and perseveratory coarticulation. The methodology is based on the measurement of 3D trajectories of fiduciary points marked on the face of a real speaker during the speech production of CVCV non-sense words. The(More)
This paper deals with the behavior of virtual environments from the collaboration point-of-view, in which actors (human or virtual beings) interact and collaborate by means of interdependent tasks. In this sense, actors may realize tasks that are dependent on tasks performed by other actors, while the interdependencies between tasks (through resource(More)
Recently some CBIR approaches have shown the use of relevance feedback to train a pattern classifier to select relevant images for retrieval. This paper revisits this strategy by using an optimum-path forest (OPF) classifier. During relevance feedback iterations, the proposed method uses the OPF classifier to decide which database images are relevant or(More)