Ricardo Oliveira

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OBJECT The authors' aim in this study was to review their experience in the use of indirect revascularization alone in a series of 14 children with moyamoya disease, in which numerous bur holes and arachnoid openings were made over each affected hemisphere. METHODS Revascularization through multiple bur holes and arachnoid openings was performed in 14(More)
OBJECT Two to five percent of pediatric brain tumors are located in the thalamus. The optimal management for these tumors remains unclear. The aim of this study was to determine whether clinical and neuroimaging features could guide treatment, and to what extent these features, together with histological diagnosis and treatment modalities, influenced(More)
This paper analyzes the performance of two implementations of J-Flow, the flow measurement tool deployed on most Juniper routers. Our work relies on both controlled experiments and analysis of traces collected at Abilene and GEANT, which provide most of the flow traces used in the research community. We uncover two measurement artifacts in J-Flow traces: a(More)
We propose a solution to the n-frame correspondence problem under the factorization framework. During the matching process, our algorithm takes explicitly into account the geometrical constraints associated to the reconstruction process. To this end, a rank constraint is imposed on the measurement matrix. Since our method relies solely on geometric(More)
The aperture problem is one of the omnipresent issues in computer vision. Its local character constrains point matching to high textured areas, so that points in gradient-oriented regions (such as straight lines) can not be reliably matched. We propose a new method to overcome this problem by devising a global matching strategy under the factorization(More)
Spatio-temporal clustering is a sub field of data mining that is increasingly gaining more scientific attention due to the advances of location-based or environmental devices that register position, time and, in some cases, other semantic attributes. This process pretends to group objects based in their spatial and temporal similarity helping to discover(More)
Measuring functional activity in brain in connection with neural stimulation faces technological challenges. Our goal is to evaluate, in relative terms, the real-time variations of local cerebral blood flow in rat brain, with a convenient spatial resolution. The use of laser Doppler flowmetry (LDF) probes is a promising approach but commercially available(More)
Establishing the correct correspondence between features in an image set remains a challenging problem amongst computer vision researchers. In fact, the combinatorial nature of feature matching effectively hinders the solution of large scale problems, which have direct applications in important areas such as 3D reconstruction and tracking. The solution is(More)