Modelagem do tempo de execução de obras civis: estudo de caso na Universidade Federal do Pará

Coutinho, Lêda Sílvia de Aguiar Lédo; Duarte, André Augusto Azevedo Montenegro; Neves, Renato Martins das; Neto, Benedito Coutinho; Maneschy, C.E.; Pinheiro, Ana Maria Guerra Serafico

doi:10.1590/s1678-86212012000100016

Cited by 8 publications

(8 citation statements)

References 6 publications

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“…Table 8 shows the analysis of the porosity value variance. Even though firing temperature had the highest values of F and p, and consequently had the greatest relevance to porosity values, its statistical significance was zero because the R2 value was 0.0 [41]. Where F is the association of the response term; SS is the sum of the squares; Df is the variance (freedom levels); ms is the quadratic average; and p is the evidence probability of the null hypothesis.…”

Section: Effect Of Feldspar Substitution With Basalt On Porosity and Flexural Strengthmentioning

confidence: 99%

Effect of Feldspar Substitution by Basalt on Pyroplastic Behaviour of Porcelain Tile Composition

et al. 2021

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This work aims to evaluate the effects of feldspar substitution by basalt on porcelain tile composition with respect to its porosity, flexural strength, and pyroplastic deformation. Three ceramic formulations with different amounts of feldspar substituted with basalt, 50% (C1), 75% (C2), and 100% (C3), were evaluated at three different temperatures, 1200, 1220, and 1240 °C. Specifically, the effect of replacing feldspar with basalt on the pyroplastic deformation of ceramic bodies was analysed using optical fleximetry. The porosity of C1 at 1200 °C was 19.3 ± 2.9%, while that of composition C3 was 22.2 ± 0.7% at 1240 °C. The flexural strength was strongly influenced by the temperature. For C1 at 1200 and 1240 °C, flexural strengths of 11.1 ± 0.6 and 22.2 ± 1.9 MPa, respectively, were obtained. Regarding fleximetry, thermal deformation decreased with an increase in the amount of feldspar substituted with basalt. It was observed that C2 and C3 deformed less at high temperatures than the other combinations of compositions and temperature, probably owing to the lower amount of residual glass phase present during cooling. Compositions with higher substitution amounts of basalt (i.e., C2 and C3) exhibited more stable thermal behaviour than C0.

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Section: Effect Of Feldspar Substitution With Basalt On Porosity and Flexural Strengthmentioning

confidence: 99%

Effect of Feldspar Substitution by Basalt on Pyroplastic Behaviour of Porcelain Tile Composition

et al. 2021

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“…Aproximadamente um terço das estações analisadas apresentaram maior contribuição do erro sistemático (SEEs A correção dos dados de temperatura proporcionou também melhora na precisão dos resultados obtidos. Antes da correção a precisão variou de 0,65 ≤ r 2 ≤ 0,81, sendo classificada por Coutinho et al (2012) como forte. Posterior a correção, a precisão aumentou para 0,66 ≤ r 2 ≤ 0,85 (Tabela 4), sendo classificada como forte e fortíssima.…”

Section: Avaliação E Correção Das Simulações De Temperatura Do Arunclassified

Avaliação e correção das simulações do modelo Eta/CPTEC – HADCM3 para o estado do Rio de Janeiro

Silva

Wanderley

Santos

et al. 2020

Rev. Bras. Geog. Fis.

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Resumo: Os modelos climáticos melhoram propiciam melhora na compreensão dos padrões de elementos climáticos e, assim, possibilitam identificar possíveis mudanças futuras. Embora essas simulações sejam alternativas satisfatórias para essa compreensão, esses modelos podem produzir simulações incertas. Deste modo, surge a necessidade de avaliar essas simulações, principalmente para o clima atual, com a finalidade de remover erros entre o que foi simulado para o clima atual e os dados observados em estações meteorológicas. Assim, esta pesquisa objetivou avaliar e corrigir simulações de temperatura do ar e precipitação obtidas pelo modelo Eta/CPTEC para o estado do Rio de Janeiro. Foram utilizados dados médios mensais de precipitação e de temperatura do ar oriundos de 108 pontos de grades simulados pelo modelo Eta para o estado do Rio de Janeiro, 1961-1990 (cenário atual) e dados de 12 (11) estações meteorológicas com séries de precipitação (temperatura do ar) também no período de 1961-1990, os quais foram utilizados para correção das simulações pela técnica de correção Delta Change Approach. Os resultados da correção das simulações foram avaliados por meio da análise de regressão linear simples e o ajuste de seus coeficientes, coeficiente de determinação (r2), erro percentual da estimativa (SEE, (mm, °C e %)) e índice de concordância de Willmott. A correção das simulações proporcionou melhora por parâmetros estatísticos avaliados e redução do erro sistemático, principalmente para as simulações de chuvas. Evaluation and correction of simulations of the Eta/CPTEC – HADCM3 model for the state of Rio de Janeiro A B S T R A C TThe climate models provide improved understanding of the patterns of climate elements and thus make it possible to identify possible future changes. Although these simulations are satisfactory alternatives for this understanding, these models can produce uncertain simulations. Therefore, it is necessary to evaluate these simulations, especially for the current climate, in order to remove errors between what was simulated for the current climate and the data observed in meteorological stations. This research objetived to evaluate and correct simulations of air temperature and rainfall obtained by the Eta/CPTEC model for the state of Rio de Janeiro. We used monthly mean rainfall and air temperature data from 108 grid points simulated by the Eta model for the state of Rio de Janeiro, for the period 1961-1990 (current scenario) and data from 12 (11) meteorological stations with rainfall series (air temperature) for the period 1961-1990, which were to correct the simulations using the Delta Change Approach technique. The results of the correction of the simulations were evaluated through simple linear regression analysis and the adjustment of their coefficients, coefficient of determination (r2), standard erro of the estimate (SEE, (mm, ° C and%)) and Willmott index. The correction of the simulations provided improvement by statistical parameters evaluated and reduction of the systematic error, mainly for the rainfall simulations.Keywords: Air temperature, rainfall, Delta Change Approach.

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“…This is very negative because the definition of construction time, as already explained, is a very relevant factor, including to avoid future conflicts between the interested parties. In order to carry out its prediction, regression models have been proposed and adopted, the explanatory variables being generally the cost of construction and the size of the work, even though the literature has pointed out that other factors can significantly affect the execution duration of a project, such as the type of project to be constructed, the constructive method, the number of floors, the productivity, the quality standard, the type of management among others CHAN, 2003;COUTINHO et al, 2012;JARKAS, 2015;SENOUCI;MUBARAK, 2016).…”

Section: Prediction Of Construction Durationmentioning

confidence: 99%

“…(b) cost of the work (BROMILOW, 1969;WALKER, 1994;CHAN, 2003;SKITMORE;NG, 2003;CZARNIGOWSKA;SOBOTKA, 2013;AHMADU et al, 2015); (g) season of the year and managerial capacity (COUTINHO et al, 2012).…”

Section: Prediction Of Construction Durationmentioning

confidence: 99%

Construction duration predictive model based on factorial analysis and fuzzy logic

et al. 2019

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Setting the building construction duration for vertical residential works is made still in the study phase of economic and financial feasibility of the project and, in most cases, in an empirical way, increasing the uncertainties and the risks to fulfill the set deadline. However, there are computational intelligence tools that can contribute to reduce the degree of uncertainty. This study aimed to investigate the use of a hybrid system to estimate the deadline for vertical residential building works from design and production characteristics using factorial analysis and Fuzzy Systems. To this end, we used information of a database from the SEURB and in some buildings construction companies in Belém, a city located in the State of Pará, northern of Brazil. For the training and construction of the Fuzzy Forecast Model, data from 71 projects were used and 16 others residential buildings were used for its validation. The results showed a significant level of assertiveness, with 75% accuracy considering a range, whose upper and lower limits were calculated from MAPE and MASE. The model presented a prediction performance superior to other models already consecrated in the literature.

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Modelagem do tempo de execução de obras civis: estudo de caso na Universidade Federal do Pará

Cited by 8 publications

References 6 publications

Effect of Feldspar Substitution by Basalt on Pyroplastic Behaviour of Porcelain Tile Composition

Effect of Feldspar Substitution by Basalt on Pyroplastic Behaviour of Porcelain Tile Composition

Avaliação e correção das simulações do modelo Eta/CPTEC – HADCM3 para o estado do Rio de Janeiro

Construction duration predictive model based on factorial analysis and fuzzy logic

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