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- Extended Performance Research on IEEE 802.11 a WPA Multi-node Laboratory LinksPublication . Carvalho, José Pacheco De; Veiga, Hugo; Pacheco, Cláudia Ribeiro; Reis, AntónioWireless communications, involving electronic devices, are increasingly important. Performance is a fundamental issue, leading to more reliable and efficient communications. Security is also, no doubt, most important. Laboratory measurements were achieved about several performance aspects of Wi-Fi IEEE 802.11a 54 MbpsWPA links. Our study enriches performance evaluation of this technology, using accessible equipment (HP V-M200 access points and Linksys WPC600N adapters). New accurate results are given, namely at OSI level 4, from TCP and UDP experiments. TCP throughput is measured against TCP packet length. Jitter and percentage datagram loss are evaluated versus UDP datagram size. Results are examined for point-to-point, point-to-multipoint and four-node point-to-multipoint links. Comparisons are also made mainly to related data obtained for Open links. Conclusions are extracted about performance of the links.
- Extended Performance Research on 5 GHz IEEE 802.11n WPA2 Laboratory LinksPublication . Carvalho, José Pacheco de; Veiga, Hugo; Pacheco, Cláudia Ribeiro; Reis, AntónioWireless communications by microwaves are increasingly important, e.g. Wi-Fi. Performance is a crucial issue, improving reliability and efficiency in communications. Security is also most important. Laboratory performance measurements are presented for Wi-Fi 5 GHz IEEE 802.11n WPA2 links. Our study contributes to performance evaluation of this technology under WPA2 encryption, using available equipments (HP V-M200 access points and Linksys WPC600N adapters). New results are given, namely for OSI level 4, from TCP and UDP experiments. TCP throughput is measured versus TCP packet length. Jitter and percentage datagram loss are measured versus UDP datagram size. Results are compared for point-to-point, point-to-multipoint and four-node point-to-multipoint links. Comparisons are also made to corresponding data obtained for Open links. Conclusions are drawn about performance of the links. © Springer Nature Singapore Pte. Ltd. 2019
- Surface Analysis of Materials by Elastic Scattering of MeV IonsPublication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Reis, AntonioAbstract—This article is about computer simulation for surface analysis through nuclear techniques, which are non-destructive. The energy analysis method is used. Energy spectra are computer simulated and compared to experimental data, giving sample composition and concentration profiles. The method, using elastic scattering of (4He)+ ions, is successfully applied to depth profiling in a target containing a thin film deposited on a thick substrate and in a thick target.
- Performance Evaluation of IEEE 802.11a 54 Mbps WPA Laboratory LinksPublication . Carvalho, José Pacheco de; Veiga, Hugo; Pacheco, Cláudia Ribeiro; Reis, AntónioThe increasing importance of wireless communications, involving electronic devices, has been widely recognized. Performance is a fundamental issue, resulting in more reliable and efficient communications. Security is also crucially important. Laboratory measurements are presented about several performance aspects of Wi-Fi IEEE 802.11a 54 Mbps WPA point-to-point and point-to-multipoint links. Our study contributes to performance evaluation of this technology under WPA encryption, using available equipments (HP V-M200 access points and Linksys WPC600N adapters). New results are given from TCP and UDP experiments concerning TCP throughput versus TCP packet length, jitter and percentage datagram loss versus UDP datagram size. Comparisons are made to corresponding results for Open links. Conclusions are drawn about the comparative performance of the links.
- Investigações de Desempenho de Ligações Laboratoriais IEEE 802.11 APublication . Carvalho, José Pacheco De; Veiga, Hugo; Pacheco, Cláudia Ribeiro; Reis, AntónioA importância das comunicações sem fios, utilizando dispositivos electrónicos, tem sido mundialmente reconhecida. O desempenho é de importância fundamental, resultando em comunicações mais fiáveis e eficientes. A segurança é também crucial. São apresentadas medidas em laboratório sobre vários aspectos de desempenho de ligações Wi-Fi IEEE 802.11 a, 54 Mbps com encriptação WPA2 e topologias ponto-a-ponto e ponto-multiponto. O nosso estudo contribui para avaliação do desempenho desta tecnologia sob encriptação WPA2, usando equipamentos disponíveis (pontos de acesso HP V-M200 e adaptadores Linksys WPC600N). São apresentados novos resultados de experiências TCP e UDP, sobre throughput TCP em função do tamanho do pacote TCP, bem como jitter e percentagem de perda de datagramas em função do tamanho do datagrama UDP. São feitas comparações com resultados correspondentes de ligações Abertas. São obtidas conclusões, em particular sobre o desempenho comparativo das ligações.
- Performance Evaluation of 5 GHz IEEE 802.11n WPA2 Laboratory LinksPublication . Carvalho, Jose Pacheco de; Veiga, Hugo; Pacheco, Cláudia Ribeiro; Reis, AntónioThe increasing importance of wireless communications, involving electronic devices, has been widely recognized. Performance is a crucial issue, leading to more reliable and efficient communications. Security is also critically important. Laboratory measurements were performed about several performance aspects of Wi-Fi IEEE 802.11n WPA2 5 GHz links. Our study contributes to performance evaluation of this technology, using available equipments (HP V-M200 access points and Linksys WPC600N adapters). New detailed results are presented and discussed, namely at OSI level 4, from TCP and UDP experiments. TCP throughput is measured versus TCP packet length. Jitter and percentage datagram loss are measured versus UDP datagram size. Results are compared for both point-to-point and point-to-multipoint links. Comparisons are also made to corresponding results obtained for Open links. Conclusions are drawn about performance of the links.
- Performance Studies Of IEEE 802.11 AC Laboratory LinksPublication . Carvalho, José Pacheco De; Veiga, Hugo; Pacheco, Cláudia Ribeiro; Reis, AntónioWireless communications, involving electronic devices, have been increasingly important in society. Performance is a fundamental issue, resulting in more reliable and efficient communications. Security is also essential. Laboratory measurements are presented about several performance aspects of Wi-Fi IEEE 802.11ac WPA2 point-to-point links. Our study contributes to performance evaluation of this technology under WPA2 encryption, using new available equipments (Cisco 2702i access points and Edimax USB 3.0 AC 1200 adapters adapters). New results are given from TCP and UDP experiments concerning TCP throughput versus TCP packet size, jitter and percentage datagram loss versus UDP datagram size. Comparisons are made to results obtained for other IEEE 802.11 technologies. Conclusions are drawn about the comparative performance of the links.
- Extended Performance Research on IEEE 802.11a 54 Mbps Multi-Node Laboratory LinksPublication . Carvalho, José Pacheco de; Veiga, Hugo; Pacheco, Cláudia Ribeiro; Reis, AntónioWireless communications, involving electronic devices, are increasingly important Performance is a fundamental issue, leading to more reliable and efficient communications. Security is also most important. Laboratory measurements were performed about several performance aspects of Wi-Fi IEEE 802.11a 54 Mbps Open links. Our study contributes to performance evaluation of this technology, using available equipments (HP V-M200 access points and Linksys WPC600N adapters). New detailed results are given, namely at OSI level 4, from TCP and UDP experiments. TCP throughput is measured versus TCP packet length. Jitter and percentage datagram loss are measured versus UDP datagram size. Results are compared for point-to-point, point-to-multipoint and four-node point-to-multipoint links. Conclusions are drawn about performance of the links. © 2018, International Association of Engineers.
- A New Performance Determination of IEEE 802.11a 54 Mbps Open Laboratory LinksPublication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Veiga, Hugo; Reis, AntónioThe increasing importance of wireless communications, involving electronic devices, has been widely recognized. Performance is a fundamental issue, leading to more reliable and efficient communications. Security is also critically important. Laboratory measurements were performed about several performance aspects of Wi-Fi IEEE 802.11a 54 Mbps Open links. Our study contributes to performance evaluation of this technology, using available equipments (HP V-M200 access points and Linksys WPC600N adapters). New detailed results are presented and discussed, namely at OSI level 4, from TCP and UDP experiments. TCP throughput is measured versus TCP packet length. Jitter and percentage datagram loss are measured versus UDP datagram size. Results are compared for both point-to-point and four-node point-to-multipoint links. Conclusions are drawn about performance of the links.
- Applications of low energy mev ion beams and computer simulation to surface analysis of materialsPublication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Reis, AntónioThis work is about surface analysis by nuclear techniques, which are essentially non-destructive, and computer simulation. The energy analysis method for nuclear reaction analysis is used. Elastic scattering is a particular and important case. Energy spectra are computer simulated and compared to experimental data, giving target composition and concentration profile information. The simulations use, mainly, target parameterization and available nuclear data. The method is successfully applied to determination of a uniform concentration profile of 18O from the (p,α) reaction in a thick oxide target. Uniform concentration profiles of 12C are obtained from the (d,p) reaction for a thick target. Uniform concentration profiles of 16O are also obtained from (d,p) and (d,α) reactions along large depths. Elastic scattering is used for depth profiling of Al and O in a thick target.