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A Unified Approach to a Class of Sampling, Interpolation, and Extrapolation Pro...
Paulo Jorge S. G. FerreiraDenote by X and Y two sets and consider u function f defined on X and with values in Y. Let U be a proper subset of X. Consider the set C of all pairs wx,f{ x)\}$ such that xeX \U. What does C imply about F? Under what circumstances does C determine F? (...)Keywords: sampling; interpolation; extrapolation; iterative methods; noniterative methodsPh.D., 1992more info: http://opac.ua.pt/F/?func=find...
Topics in Multiresolution and Filter Banks
Si-Qi Cao; Paulo Jorge S. G. FerreiraThis thesis studies a number of topics relevant to signal and image representation and coding, in the context of multiresolution analysis by filter banks and wavelets. It discusses signal approximation through multiresolution analysis, and applications to the study of the symptotic approximation power of radial basis function neural networks; it proposes a genuine finite-dimensional framework for multiresolutio...
Signal Reconstruction Techniques Applied to Speech Transmission
Salviano Filipe S. P. Soares; Paulo Jorge S. G. FerreiraThe transmission of speech through a packet-based network may result in packets reaching the destination out of order and subject to unpredictable delays. For real-time reproduction, it is necessary to provide some means of dealing with the unavailable packets, to prevent communication failures. A correct sample at a wrong time is a wrong sample! (...)Keywords: oversampling; interpolation; interleaving; Et...
Tomographic Techniques and Tomography Reconstruction Algorithms. The SPECT Case
Silvia De Francesco; Paulo Jorge S. G. FerreiraNowadays, different tomographic techniques are largely utilised in clinical practice, giving a precious contribution to diagnosis. From the clinical point of view, each of these techniques has a big potential, for instance to plan therapeutic strategies. (...)Keywords: tomography; tomographic techniques; tomographic reconstruction algorithms; spect; attenuation; attenuation correction algorithmsM.S.,...
Does banning price discrimination promote entry and increase welfare? A model o...
Jorge, S.F.; Pires, C.P.In this paper we investigate the impact of firms’ pricing policies upon entry and welfare under duopoly price competition and product differentiation. We consider a model where an incumbent serves two distinct and independent geographical markets and an entrant may enter in one of the markets. Our results show that discriminatory pricing may be either more, less or equally favorable to entry than uniform pricin...
Efficient Optimization Algorithm for Space-Variant Mixture of Vector Fields
Nascimento, Jacinto C.; Barão, Miguel; Marques, Jorge S.; Lemos, João M.This paper presents a new algorithm for trajectory classifi- cation of human activities. The presented framework uses a mixture of parametric space-variant vector fields to describe pedestrian’s trajecto- ries. An advantage of the proposed method is that the vector fields are not constant and depend on the pedestrian’s localization. This means that the switching motion among vector fields may occur at any image...
Low and decreasing vaccine effectiveness against influenza A(H3) in 2011/12 amo...
Kissling, E.; Valenciano, M.; Larrauri, A.; Oroszi, B.; Cohen, J.M.; Nunes, Baltazar; Pitigoi, D.; Rizzo, C.; Rebolledo, J.; Paradowska-Stankiewicz, I.Within the Influenza Monitoring Vaccine Effectiveness in Europe (I-MOVE) project we conducted a multicentre case–control study in eight European Union (EU) Member States to estimate the 2011/12 influenza vaccine effectiveness against medically attended influenza-like illness (ILI) laboratory-confirmed as influenza A(H3) among the vaccination target groups. Practitioners systematically selected ILI / acute respi...
Recursive bayesian identification of nonlinear autonomous systems
Simão, Tiago; Barão, Miguel; Marques, Jorge S.This paper concerns the recursive identification of nonlinear discrete-time systems for which the original equations of motion are not known. Since the true model structure is not available, we replace it with a generic nonlinear model. This generic model discretizes the state space into a finite grid and associates a set of velocity vectors to the nodes of the grid. The velocity vectors are then interpolated t...
Alignment of velocity fields for video surveillance
Marques, Jorge S.; Barão, Miguel; Lemos, João M.Velocity fields play an important role in surveillance since they describe typical motion behaviors of video objects (e.g., pedestrians) in the scene. This paper presents an algorithm for the alignment of velocity fields acquired by different cameras, at different time intervals, from different viewpoints. Velocity fields are aligned using a warping function which maps corresponding points and vectors in both f...
Alignment of velocity fields for video surveillance
Marques, Jorge S.; Barão, Miguel; Lemos, João M.Velocity fields play an important role in surveillance since they describe typical motion behaviors of video objects (e.g., pedestrians) in the scene. This paper presents an algorithm for the alignment of velocity fields acquired by different cameras, at different time intervals, from different viewpoints. Velocity fields are aligned using a warping function which maps corresponding points and vectors in both f...
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