Filipe Freitas

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OBJECTIVE This paper proposes an indexing and retrieval solution to gather information from distributed DICOM documents by allowing searches and access to the virtual data repository using a Google-like process. METHODS AND MATERIALS The medical imaging modalities are becoming more powerful and less expensive. The result is the proliferation of equipment(More)
Peer-to-peer overlays provide an ideal substrate for worm propagation. P2p-assisted worms have the potential to spread faster than traditional scanning worms because they have knowledge of a subset of the overlay nodes, and choose these nodes to propagate themselves ; and also because they can avoid traditional detection mechanisms. We present a novel(More)
The emerging context of e-Science imposes new scenarios and requirements for digital preservation. In particular, the data must be reliably stored, for which redundancy is a key strategy. But managing redundancy must take into account the potential failure of component. Considering that correlated failures can affect multiple components and potentially(More)
Topological worms, such as those that propagate by following links in an overlay network, have the potential to spread faster than traditional random scanning worms because they have knowledge of a subset of the overlay nodes, and choose these nodes to propagate themselves; and also because they can avoid traditional detection mechanisms. Furthermore, this(More)
While several proposals for the specification and implementation of various consistency models exist, little is known about what is the consistency currently offered by online services with millions of users. Such knowledge is important, not only because it allows for setting the right expectations and justifying the behavior observed by users, but also(More)
Artificial neural networks (ANNs) have been widely used over the last three decades. During this period, many hardware and software solutions have been developed and today a new user entering the field can make a fast trial to this artificial intelligence solution with commercial software and hardware, instead of developing a solution from scratch thus(More)
The electrocardiogram (ECG) is extensively used as a low cost diagnostic tool to provide information concerning the heart performance. The time interval between consecutive beats in the ECG (tachogram) is the simplest cardiovascular signal to characterize heart rate variability (HRV), in time and frequency domains, and has been applied in various clinical(More)
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