Navegando por Assunto "Modelagem temporal multivariada"

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Acesso aberto (Open Access)
Modelagem canais de comunicações móveis com a utilização de series temporais e geoestatísticas
(Universidade Federal do Pará, 2013-03-12) ROZAL, Edilberto Oliveira; QUEIROZ, Joaquim Carlos Barbosa; http://lattes.cnpq.br/4383935463464893; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
This work presents the results of propagation channel modeling, based on multivariate time series models using data collected in measurement campaigns and the main characteristics of urbanization in the city of Belem-PA. Transfer function models were used to evaluate effects on the time series of received signal strength (dBm) which was used as the response variable and as explanatory variables of the height of buildings and distances between buildings. As time series models disregard to the possible correlations between neighboring samples, we used a geostatistical model to establish the correctness of this model error. This phase of the work consisted of a set of procedures necessary to geostatistical techniques. Aiming at the analysis on two dimensions for data spatially distributed, with respect to the interpolation of surfaces generated from georeferenced samples obtained from residues of received signal power computed using the model series. The results obtained with the proposed model showed an excellent performance, with mean square error in the order of 0.33 dB compared to the measured signal, considering the data of the eleven routes from the center of the city of Belém/Pa. From the map of the spatial distribution of the received signal strength (dBm), one can easily identify areas below or above dimensional in terms of this variable, that is benefited or damaged compared with the signal reception, which may result in a greater investment of the local operator (concessionaire mobile phone) in those regions where the signal is weak.
Acesso aberto (Open Access)
Modelagem Hidrológica Estocástica Aplicada ao Rio Tocantins para a Cidade de Marabá-PA
(Universidade Federal do Pará, 2016-03) CÂMARA, Renata Kelen Cardoso; ROCHA, Edson José Paulino da; PROTÁZIO, João Marcelo Brazão; QUEIROZ, Joaquim Carlos Barbosa; RIBEIRO, Wanda Maria do Nascimento; SIQUEIRA, Ionara Santos; LIMA, Aline Maria Meiguins de
Hydrology studies show that it is possible to avoid natural disasters through the proper use of hydrological forecasts. In this work we used the Box-Jenkins Methodology (Time Series Analysis) to model the daily level of the Tocantins river in the city of Maraba - PA, in order to predict floods caused by its regular increase, an event that usually puts the resident population of risk areas in vulnerable situations. For the study, we used the daily levels of data observed in gauged stations of Maraba and Carolina and Conceição do Araguaia National Water Agency (ANA), the period of 01/12/2008 to 31/03/2011. It was evident that the adjusted model was able to capture the dynamics of time series with good prognosis for a period of seven days with a maximum absolute error of 0.08 m and with precision in forecasting over 99%. The forecasting model showed good results and can then be used as support tools for Civil Defense, assisting in the planning and preparation of preventive actions for the city of Maraba.