Comparação Entre Gráficos De Controle De Shewhart, Cusum E Mmep No Processo De Irrigação Por Aspersão Convencional

Abstract

COMPARAÇÃO ENTRE GRÁFICOS DE CONTROLE DE SHEWHART, CUSUM E MMEP NO PROCESSO DE IRRIGAÇÃO POR ASPERSÃO CONVENCIONAL JIAM PIRES FRIGO1; MARCIO ANTONIO VILAS BOAS2; JIANICE PIRES FRIGO2 E ELISANDRO PIRES FRIGO3 1 Instituto Latino-Americano de Tecnologia, Infraestrutura e Território - ILATIT (UNILA), Av. Tancredo Neves, 3838 - Porto Belo, CEP 85867-970, Foz do Iguaçu, PR, Fone (45)99993 4783, e‑mail:jianfrigo@gmail.com2 Centro de Ciências Exatas e Tecnológicas, Programa de Pós Graduação em Engenharia Agrícola (Unioeste), R. Universitária, 2069 - Jardim Universitário CEP 85819-110, Cascavel-PR3 Universidade Federal do Paraná, Campus Palotina R. Pioneiro, 2153 - Dallas, CEP 85950-000, Palotina-PR 1 RESUMO O objetivo deste estudo foi comparar os resultados da utilização dos gráficos de controle de Shewhart para medidas individuais, com os gráficos de controle média móvel exponencialmente ponderada (MMEP) e soma cumulativa (CUSUM), aplicados no controle de qualidade da irrigação. Foram realizados 60 ensaios de irrigação em um sistema por aspersão convencional. As análises do processo de controle de qualidade do sistema de irrigação foram realizadas por meio dos gráficos de Shewhart (Xbarra), gráficos MMEP e CUSUM. Todos os procedimentos para os ensaios de uniformidade da irrigação foram realizados conforme recomendação NBR ISO 7749-2 (ABNT, 2000). Para a avaliação do sistema foi utilizado o Coeficiente de Uniformidade de Christiansen (CUC). O gráfico de controle MMEP apresentou-se bastante suscetível quando utilizado em dados auto correlacionados, com ocorrências de alarmes falsos. Para dados independentes (pelo modelo ARIMA), o gráfico CUSUM foi mais sensível ao detectar as variações ocorridas na irrigação devido à velocidade do vento, quando comparado aos gráficos MMEP e Shewhart para os mesmos dados. Na irrigação por aspersão, relacionando CUC com velocidade do vento, o gráfico de Shewhart foi mais indicado pela simplicidade, robustez e facilidade de interpretação, mesmo na presença de dados que violam a suposição de independência. Os gráficos de controle de Shewhart, MMEP e CUSUM provaram serem ótimas ferramentas estatísticas no estudo da irrigação por aspersão convencional, demonstrando muito bem a variabilidade no processo. Palavras-Chave: água, vento, Coeficiente de Christiansen, Controle de qualidade. FRIGO, J.P.; VILAS BOAS, M.A.; FRIGO, J.P.; FRIGO, E.P.COMPARISON BETWEEN SHEWHART CONTROL CHARTS, CUSUM AND MMEP IN PROCESS OF CONVENTIONAL IRRIGATION SPRINKLER 2 ABSTRACT This study aimed to compare the results of Shewhart control charts use for individual measures with exponentially weighted moving average (MMEP) and cumulative sum (CUSUM) control charts applied in quality control of conventional sprinkler irrigation. Sixty irrigation trials were set up in a conventional sprinkler system. The analyses of the quality control process of the irrigation system were performed by means of Shewhart charts (Xbarra) charts, MMEP and CUSUM. All procedures for testing uniformity of irrigation were performed as recommended by ISO 7749-2 (ABNT, 2000). For the evaluation of the system, it was used Christiansen Uniformity Coefficient (CUC). The control chart MMEP showed to be quite susceptible when used in auto correlated data with instances of false alarms. For independent data (the ARIMA model), the CUSUM tabular chart was more sensitive to detect variations in irrigation due to wind speed, when compared to MMEP and Shewhart charts for the same data. In sprinkler irrigation, relating CUC with wind speed, the Shewhart chart was better due to such features as simplicity, robustness and easiness of interpretation, even in the presence of data that violate the assumption of independence. The Shewhart control charts, CUSUM and MMEP statistics proved to be great tools in the study of irrigation sprinkler, demonstrating very well the variability in the process. Keywords: water, wind, Christiansen coefficient, control charts, Quality control.

Techniques for Quality Control in Football Field Located in Agricultural Area

“…For Frigo et al (2016), the control charts for conventional irrigation indicated that the process was out of control at the point where the wind speed was equal to or greater than 2.63 m s -1 , that is, the wind speed, although lower to the present study, significantly affected the uniformity of water distribution.…”

“…For Frigo et al (2016) due to the simplicity, robustness and ease of interpretation of the data in conventional sprinkler irrigation systems, Shewhart's graphs compared to the CUSUM and EWMA charts were the most indicated. On the other hand, Andrade et al (2017) indicated the EWMA and CUSUM graphs for analysis of irrigation uniformity by micro-sprinklers because of their accuracy in detecting small variations.…”

Statistical Quality Control in Uniformity of Drip Irrigation With Different Slopes

“…The comparison of UC and UD in the Shewhart chart ( Figure 4) shows a different behavior, and the level system was under statistical control. The Shewhart control chart proved to be a good statistical tool in the study of conventional sprinkler irrigation, demonstrating very well the process variability (Frigo et al, 2016).…”

“…The Shewhart control chart consists of a center line representing the mean of the desired quality characteristic, an upper control limit line (UCL) and another lower control limit line (LCL) (Frigo et al, 2016 ).…”

Effect of Calcium Hypochlorite in Drip Irrigation System After Application of Red Potassium Chloride

“…The quality control charts are useful for the operational simplicity and effectiveness in problem detection (Pedrini & Ten Caten, 2011), and are used successfully in the monitoring of many processes, including for monitoring irrigation systems (J. Frigo, Vilas Boas, J. P. Frigo, & E. Frigo, 2016). The application of control charts assumes that the process quality characteristic data is independent and identically distributed.…”