Browsing by Author "Pereira, A."
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- Cognition inspired format for the expression of computer vision metadataPublication . Castro, H.; Monteiro, J.; Pereira, A.; Silva, D.; Coelho, G.; Carvalho, P.Over the last decade noticeable progress has occurred in automated computer interpretation of visual information. Computers running artificial intelligence algorithms are growingly capable of extracting perceptual and semantic information from images, and registering it as metadata. There is also a growing body of manually produced image annotation data. All of this data is of great importance for scientific purposes as well as for commercial applications. Optimizing the usefulness of this, manually or automatically produced, information implies its precise and adequate expression at its different logical levels, making it easily accessible, manipulable and shareable. It also implies the development of associated manipulating tools. However, the expression and manipulation of computer vision results has received less attention than the actual extraction of such results. Hence, it has experienced a smaller advance. Existing metadata tools are poorly structured, in logical terms, as they intermix the declaration of visual detections with that of the observed entities, events and comprising context. This poor structuring renders such tools rigid, limited and cumbersome to use. Moreover, they are unprepared to deal with more advanced situations, such as the coherent expression of the information extracted from, or annotated onto, multi-view video resources. The work here presented comprises the specification of an advanced XML based syntax for the expression and processing of Computer Vision relevant metadata. This proposal takes inspiration from the natural cognition process for the adequate expression of the information, with a particular focus on scenarios of varying numbers of sensory devices, notably, multi-view video.
- Evaluation of nasal patency in children: Data of737 consecutive rhinomanometry tests before and after vasoconstrictor treatmentPublication . Gonçalves, I.; Jacinto, Tiago; Amaral, Rita; Pereira, A.; Araujo, L.; Couto, M.; Fonseca, J.; Amaral, RitaRhinomanometry is a simple and useful method for objective evaluation of nasal airway patency. However, there is a lack of published studies in pediatric patients. We aimed to evaluate nasal patency assessed by rhinomanometry and its variation after administration of an intranasal vasoconstrictor in children.
- A large area TOF-tracker device based on multi-gap Resistive Plate ChambersPublication . Assis, P.; Bernardino, A.; Blanco, A.; Luz, R.; Mendes, L.; Michel, J.; Neiser, A.; Pereira, A.; Pimenta, M.; Shellard, R.; Traxler, M.; Clemêncio, Filomena; Carolino, N.; Cunha, O.; Ferreira, M.; Fonte, P.; Lopes, L.; Loureiro, C.The TOF-tracker concept, the simultaneous measurement of accurate time and bi-dimensional space coordinates in a single gaseous detector, has been previously demonstrated. The detector yielded a time resolution of 77 ps σ along with a bi-dimensional position resolution of 38 μm σ over a full active area of 60 × 60 mm2. In here, we report about a large area, 1550 × 1250 mm2, TOF-tracker device, tested by tracking cosmic muons, yielding a position resolution down to 1.33 mm σ, a simultaneous time resolution of 150 ps σ and 92% detection efficiency, over the entire area of the detector. The sub-millimetre electronic resolution of the readout chain suggests that the position resolution here reported could be dominated by non-corrected systematic effects and therefore it could be yet significantly improved.
- Outdoor systems performance and upgradePublication . Lopes, L.; Andringa, S.; Assis, P.; Blanco, A.; Carolino, N.; Cerda, M.A.; Clemêncio, Filomena; Conceição, R.; Cunha, O.; Dobrigkeit, C.; Ferreira, M.; Loureiro, C.; Mendes, L.; Nogueira, J.C.; Pereira, A.; Pimenta, M.; Saraiva, J.; Sarmento, R.; Teixeira, P.; Tomé, B.Over the last two decades, the possibility of using RPCs in outdoors systems has increased considerably. Our group has participated in this effort by installing several systems and continues to work on their optimization, while simultaneously studying and developing new approaches that can use RPCs in outdoor applications. In particular, four detectors were deployed in the field at the Pierre Auger Observatory in 2019 remained inactive, awaiting the commissioning of support systems. During the pandemic the detectors were left without gas flow for more thantwo years, but were recently reactivated with no major problems. The Lou Mu project combines particle physics and geophysics in order tomapmeter-scale geologic structures, using Muon Tomography. Transmission muography is sensitive to the total amount of matter crossed by the muons, allowing to separate targets of different densities. In this exploratory project, it serves to identify unconsolidated rockzones, like geological faults and ore masses around an old Pyritemine,now converted into a science center. The general goal is to compare how effective is the muographic survey when compared with the more standard geophysical techniques. The development of the RPC system used and the data from the last two years will be presented. Finally, recent advances in a large area(1m2) doubl egap-sealed RPC will be presented.