Navegando por Assunto "Measurement"

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Acesso aberto (Open Access)
Métricas de QoE/QoS de vídeo em redes sem fio para auxilio ao planejamento de ambientes indoor utilizando uma abordagem bayesiana
(Universidade Federal do Pará, 2015-03-30) CARVALHO, André Augusto Pacheco de; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The evolution of applications on wireless networks has grown in recent years, due to the increased number of smartphone users, tablets and others. The availability of demanding services such as video transmission, affects Quality Experience (QoE) and Quality of Service (QoS) provided to domestic users and trade, this had stimulated the study of new resource management techniques networks, aiming to provide quality services to a customer each increasingly demanding. This thesis presents a methodology Intelligence Artificial using a Bayesian network with a hybrid evaluation strategy analyzing the behavior metrics QoE and QoS in the LAN network design wireless. The diversity of the place of Measurements chosen compound materials such as brick, glass, wood and concrete. It was necessary first to map all the points to be measured before and after deliberately placing each barrier outdated the signal. Metrics as level Receiver Signal Strength Intensity signal (RSSI) Jitter, delay end to end network for the video transmission, PeakSignal-to-NoiseRatio (PSNR) and Structural Similarity (SSIM) were collected during the Measurements. And using the Bayesian Network inferences were made for each metric and could not find satisfactory results for the proposed solution assist the wireless network planning in indoor environments. Enabling demonstrate that up to 10 meters away from the transmitter, the signal has its best power, and delay metrics in order to have more than 65% probability that the lower delay range and following this optimum performance the Jitter has more than 65% probability in this lower range. And the QE metrics, PSRN and SSIM have a similar behavior and has more than 80% probability of getting your greater value, and consequently the video has its best reception. These results show that does not preclude the use of this proposal in other situations.
Acesso aberto (Open Access)
Transmissão DSL em modo fantasma: medições e avaliação de desempenho
(Universidade Federal do Pará, 2012-12-07) GOMES, Diego de Azevedo; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
Demand for bit rate is increasing every year, mainly due to the incorporation of online applications into people's life. So the companies which provide this type of service are always investing in research for technologies that enable increased bit rate with a good value for money. Following this perspective, this paper presents transmission phantom mode, which aims to increase the overall rate of transmission of bits in DSL systems when multiple copper pairs available. Here we also show results and discussions on performance of phantom mode. We discuss procedures for performing measurements in phantom mode at frequencies from 100 kHz to 300 MHz, in a way that allows the measurement of phantom mode and deferential mode with the same setup. New results are presented on the direct channel, far-end crosstalk (FEXT) and mode conversion for a Cat-5e cable of 50 meters. Among other facts, we verify large deference’s in the direct channel phantom mode when comparing rolled and unrolled cable measurements, and that manner how we build the phantom mode greatly inuences the behavior of the curves of direct channel, FEXT and mode conversion. We also present results of estimating bit rate when using phantom mode and deferential mode simultaneously, and observed that there is a gain of up to 60 when we use this two modes and vectoring.