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- 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.
- 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.
- 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.
- Impacto dos sistemas de climatização e AQS na certificação energética de edifícios no âmbito do RCCTE: Estudo de casoPublication . Pacheco, Cláudia Ribeiro; Nepomuceno, Miguel; Silva, Pedro Dinho daO artigo descreve o estudo de um caso relativo a uma moradia unifamiliar, onde se comparam os desempenhos de dez combinações diferentes de sistemas de climatização (aquecimento e arrefecimento) e de sistemas convencionais de apoio para produção de água quente sanitária (AQS). Assumiu-se a existência de colectores solares que captam uma energia equivalente em todo o estudo e definiu-se como solução padrão para climatização e AQS aquela admitida por defeito no RCCTE para as situações em que estes sistemas não são especificados. O estudo compara as diferentes soluções em termos do valor dispendido nas facturas energéticas anuais para climatização e AQS, o custo estimado de aquisição dos equipamentos, o período de retorno simples de investimento face à solução padrão, as emissões anuais de gases de efeito de estufa e a classe energética. O estudo permitiu verificar que a uma classe energética mais elevada não corresponde necessariamente uma menor factura energética.
- Performance Assessment of IEEE 802.11a 54 Mbps WEP Laboratory LinksPublication . Carvalho, José Pacheco de; Pacheco, Cláudia Ribeiro; Veiga, Hugo; Reis, AntónioThe 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 critically important. Laboratory measurements were performed about several performance aspects of Wi-Fi IEEE 802.11a 54 Mbps WEP links. Our study contributes to performance evaluation of this technology, using available equipments (HP V-M200 access points and Linksys WPC600N adapters). New 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.
- Impacto dos sistemas de climatização e AQS na certificação energética de edifícios no âmbito do RCCTE: caso de estudoPublication . Pacheco, Cláudia Francisca Figueiredo Pires Ribeiro; Nepomuceno, Miguel Costa Santos; Silva, Pedro Nuno Dinho Pinto daNo presente trabalho são apresentados os principais sistemas de climatização tanto para aquecimento como para arrefecimento, para além de diversos sistemas de produção de águas quentes sanitárias. São também abordados aspectos relativos ao contexto nacional energético e ambiental, o plano nacional de eficiência energética, as condições de conforto termohigrométrico interior nas habitações, os tipos de ventilação existentes e os diversos tipos de energias renováveis utilizados. A proposta desenvolvida no âmbito do presente trabalho, assenta em procedimentos de cálculo que, tendo como base o projecto de térmica do edifício do caso de estudo, permitem realizar a simulação de diferentes combinações de sistemas de climatização para aquecimento, arrefecimento e sistemas convencionais de produção de AQS. Conseguem-se comparar os valores obtidos em termos de emissões anuais de gases de efeito de estufa, o valor dispendido nas facturas energéticas anual e mensal para climatização e preparação de AQS, a classe energética e o custo de aquisição, instalação e manutenção dos equipamentos.