Search

Your search keyword '"Pereira, Americo"' showing total 13 results
Start Over Author "Pereira, Americo"
13 results on '"Pereira, Americo"'

1. An RPC-PET brain scanner demonstrator: first results

Author

Fonte, Paulo, Lopes, Luís, Alves, Rui, Carolino, Nuno, Crespo, Paulo, Couceiro, Miguel, Cunha, Orlando, Dias, Nuno, Ferreira, Nuno C., Fetal, Susete, Lopes, Ana L., Michel, Jan, Moreira, Jorge, Pereira, Américo, Saraiva, João, Silva, Carlos, Silva, Magda, Traxler, Michael, Abrunhosa, Antero, Blanco, Alberto, Castelo-Branco, Miguel, and Pimenta, Mário

Subjects
Physics - Instrumentation and Detectors, Physics - Medical Physics
Abstract

We present first results from a Positron Emission Tomography (PET) scanner demonstrator based on Resistive Plate Chambers and specialized for brain imaging. The device features a 30 cm wide cubic field-of-view and each detector comprises 40 gas gaps with 3D location of the interaction point of the photon. Besides other imagery, we show that the reconstructed image resolution, as evaluated by a hot-rod phantom, is sub-millimetric, which is beyond the state-of-the-art of the standard PET technology for this application.

Published
2022
Full Text
View/download PDF

3. Prototype of an affordable pressure-controlled emergency mechanical ventilator for COVID-19

Author

Pereira, Américo, Lopes, Luís, Fonte, Paulo, Póvoa, Pedro, Santos, Telmo G., Martinho, Alberto, Neves, Ângela, Bugalho, António, Gabriel-Santos, António, Pimenta, Gonçalo Gaspar Bentes, Goês, João, Martins, João, Oliveira, João Pedro, Santos, José Paulo, Gil, Luís C., Domingues, Miguel Onofre, Cunha, Orlando, de Sousa, Pedro Pinheiro, Rodrigues, Tiago A., Duarte, Valdemar R., Abrunhosa, Antero, Grilo, António, Nascimento, João Agostinho do, and Pimenta, Mário

Subjects
Physics - Medical Physics
Abstract

We present a viable prototype of a simple mechanical ventilator intended as a last resort to ventilate COVID-19 patients. The prototype implements the pressure-controlled continuous mandatory ventilation mode (PC-CMV) with settable breathing rates, inspiration/expiration time ratios and FiO2 modulation. Although safe, the design aims to minimize the use of technical components and those used are common in industry, so its construction may be possible in times of logistical shortage or disruption or in areas with reduced access to technical materials and at a moderate cost, affordable to lower income countries. Most of the device can be manufactured by modest technical means and construction plans are provided., Comment: This version differs from version 2 in that it includes toxicological and bio-safety tests and updated electronics

Published
2020

4. An RPC-PET brain scanner demonstrator: First results

Author

Fonte, Paulo, Lopes, Luís, Alves, Rui, Carolino, Nuno, Crespo, Paulo, Couceiro, Miguel, Cunha, Orlando, Dias, Nuno, Ferreira, Nuno C., Fetal, Susete, Lopes, Ana L., Michel, Jan, Moreira, Jorge, Pereira, Américo, Saraiva, João, Silva, Carlos, Silva, Magda, Traxler, Michael, Abrunhosa, Antero, Blanco, Alberto, Castelo-Branco, Miguel, and Pimenta, Mário

Published
2023
Full Text
View/download PDF

5. Autonomous RPCs for a Cosmic Ray ground array

Author

Assis, Pedro, Blanco, Alberto, Carolino, Nuno, Conceição, Ruben, Cunha, Orlando, Dobrigkeit, Carola, Ferreira, Miguel, Fonte, Paulo, Lopes, Luis, Luz, Ricardo, Martins, Victor Barbosa, Mendes, Luis, Pereira, Américo, Pimenta, Mário, Sarmento, Raul, Shellard, Ronald, de Souza, Vitor, and Tomé, Bernardo

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

We report on the behaviour of Resistive Plate Chambers (RPC) developed for muon detection in ultra-high energy cosmic ray (UHECR) experiments. The RPCs were developed for the MARTA project and were tested on field conditions. These RPCs cover an area of $1.5 \times 1.2\,{m^2}$ and are instrumented with 64 pickup electrodes providing a segmentation better than $20\,$cm. By shielding the detector units with enough slant mass to absorb the electromagnetic component in the air showers, a clean measurement of the muon content is allowed, a concept to be implemented in a next generation of UHECR experiments. The operation of a ground array detector poses challenging demands, as the RPC must operate remotely under extreme environmental conditions, with limited budgets for power and minimal maintenance. The RPC, DAQ, High Voltage and monitoring systems are enclosed in an aluminium-sealed case, providing a compact and robust unit suited for outdoor environments, which can be easily deployed and connected. The RPCs developed at LIP-Coimbra are able to operate using a very low gas flux, which allows running them for few years with a small gas reservoir. Several prototypes have already been built and tested both in the laboratory and outdoors. We report on the most recent tests done in the field that show that the developed RPCs have operated in a stable way for more than 2 years in field conditions., Comment: To appear in the proceedings of the 35th International Cosmic Ray Conference (ICRC2017), Busan, South Korea. Presented by R. Concei\c{c}\~{a}o. 8 pages

Published
2017

6. Video Based Group Tracking and Management

Author

Pereira, Américo, Familiar, Alexandra, Moreira, Bruno, Terroso, Teresa, Carvalho, Pedro, Côrte-Real, Luís, Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Campilho, Aurélio, editor, and Karray, Fakhri, editor

Published
2016
Full Text
View/download PDF

12. Efficient CIEDE2000-Based Color Similarity Decision for Computer Vision.

Author

Pereira, Americo, Carvalho, Pedro, Coelho, Gil, and Corte-Real, Luis

Subjects
*COMPUTER vision, *VISUAL perception, *COLOR, *IMAGE processing, *COLORS, *APPLICATION software, *COMPUTER algorithms
Abstract

Color and color differences are critical aspects in many image processing and computer vision applications. A paradigmatic example is object segmentation, where color distances can greatly influence the performance of the algorithms. Metrics for color difference have been proposed in the literature, including the definition of standards such as CIEDE2000, which quantifies the change in visual perception of two given colors. This standard has been recommended for industrial computer vision applications, but the benefits of its application have been impaired by the complexity of the formula. This paper proposes a new strategy that improves the usability of the CIEDE2000 metric when a maximum acceptable distance can be imposed. We argue that, for applications where a maximum value, above which colors are considered to be different, can be established, then it is possible to reduce the amount of calculations of the metric, by preemptively analyzing the color features. This methodology encompasses the benefits of the metric while overcoming its computational limitations, thus broadening the range of applications of CIEDE2000 in both the computer vision algorithms and computational resource requirements. [ABSTRACT FROM AUTHOR]

Published
2020
Full Text
View/download PDF

13. Kant’s transcendentalism and ethics a scepticism searching to overcome itself in contradiction

Author

Pereira, Americo Jose Pinheira and Veritati - Repositório Institucional da Universidade Católica Portuguesa

Subjects
Kant, Transcendentalism, Ethics, Contradiction, Ética, Hume, Transcendentalismo, Contradição
Abstract

A experiência é apenas um estado instantâneo de impressão sensível nisso que tem a experiência. Esta expressão resume a substância epistemológica do que constitui a posição empiricista polarizada na forma de pensamento paradigmatizada por David Hume e acriticamente aceite por Immanuel Kant. Tal posição, ao invés da tese aristotélica, impede qualquer modo trans-sensível, logo, trans-material de pensamento. A metafísica torna-se impossível. Kant procura ultrapassar esta impossibilidade através da criação de uma construção lógico-epistemológica que designa como arquitectónica transcendental. O mundo em que o transcendentalismo kantiano pôs a intelectualidade a viver é um mundo reduzido a um jogo lógico, insubstante para além de si próprio, num solipsismo que condena o ser humano a viver definitivamente alienado de uma realidade que não seja a de seu próprio pensamento. A sua proposta de superação deste novo impasse através de uma teoria da acção cai na contradição de postular teoricamente algo que a razão nunca pode postular, pois não há ou pode haver qualquer referência empírica. A verdade da razão teórica impede a verdade quer da razão prática quer da razão estética., Experience is just an instantaneous state of sensitive impression occurring within that which has that experience. Thus may be resumed the epistemological substance of that which constitutes the empiricist stand polarized in the form of thought whose paragon is David Hume and that was non-critically accepted by Immanuel Kant. Such position, contrary to the Aristotelian thesis, prevents any trans-sensitive, thus, trans-material, mode of thought. Metaphysics becomes impossible. Kant procures to overcome this impossibility through the creation of a logic-epistemological construction that he designates as transcendental architectonics. The world within which Kantian transcendentalism obliged the intellectuality to live is a world reduced to a logic game, lacking any substance other than itself, a solipsism that condemns the human being to living definitely alienated from a reality different from the one of the mere thought. His overcoming proposal for this new standstill by means of a new theory of action labours in the contradiction of theoretically postulating something that reason can never postulate for there is not and there cannot be any empirical reference. The truth of theoretical reason prevents the truth of practical or aesthetical reason.

Published
2015

Catalog

Books, media, physical & digital resources
See catalog results