Constructing a Control Chart Using Functional Data

This study proposes a control chart based on functional data to detect anomalies and estimate the normal output of industrial processes and services such as those related to the energy efficiency domain. Companies providing statistical consultancy services in the fields of energy efficiency; heating...

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Main Authors: Miguel Flores, Salvador Naya, Rubén Fernández-Casal, Sonia Zaragoza, Paula Raña, Javier Tarrío-Saavedra
Format: Article
Language:English
Published: MDPI AG 2020-01-01
Series:Mathematics
Subjects:
Online Access:https://www.mdpi.com/2227-7390/8/1/58
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author Miguel Flores
Salvador Naya
Rubén Fernández-Casal
Sonia Zaragoza
Paula Raña
Javier Tarrío-Saavedra
author_facet Miguel Flores
Salvador Naya
Rubén Fernández-Casal
Sonia Zaragoza
Paula Raña
Javier Tarrío-Saavedra
author_sort Miguel Flores
collection DOAJ
description This study proposes a control chart based on functional data to detect anomalies and estimate the normal output of industrial processes and services such as those related to the energy efficiency domain. Companies providing statistical consultancy services in the fields of energy efficiency; heating, ventilation and air conditioning (HVAC); installation and control; and big data for buildings, have been striving to solve the problem of automatic anomaly detection in buildings controlled by sensors. Given the functional nature of the critical to quality (CTQ) variables, this study proposed a new functional data analysis (FDA) control chart method based on the concept of data depth. Specifically, it developed a control methodology, including the Phase I and II control charts. It is based on the calculation of the depth of functional data, the identification of outliers by smooth bootstrap resampling and the customization of nonparametric rank control charts. A comprehensive simulation study, comprising scenarios defined with different degrees of dependence between curves, was conducted to evaluate the control procedure. The proposed statistical process control procedure was also applied to detect energy efficiency anomalies in the stores of a textile company in the Panama City. In this case, energy consumption has been defined as the CTQ variable of the HVAC system. Briefly, the proposed methodology, which combines FDA and multivariate techniques, adapts the concept of the control chart based on a specific case of functional data and thereby presents a novel alternative for controlling facilities in which the data are obtained by continuous monitoring, as is the case with a great deal of process in the framework of Industry 4.0.
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spelling doaj.art-8f06ff9f6f2f4701bec0e13b92f3dd3d2022-12-21T23:44:16ZengMDPI AGMathematics2227-73902020-01-01815810.3390/math8010058math8010058Constructing a Control Chart Using Functional DataMiguel Flores0Salvador Naya1Rubén Fernández-Casal2Sonia Zaragoza3Paula Raña4Javier Tarrío-Saavedra5MODES Group, Department of Mathematics, Escuela Politécnica Nacional, 170517 Quito, EcuadorMODES Group, CITIC, ITMATI, Department of Mathematics, Escola Politécnica Superior, Campus Industrial, Universidade da Coruña, Mendizábal s/n, 15403 Ferrol, SpainMODES Group, CITIC, Department of Mathematics, Faculty of Computer Science, Campus de Elviña, Universidade da Coruña, 15008 A Coruña, SpainPROTERM Group, Department of Naval and Industrial Engineering, Campus Industrial, Universidade da Coruña, Mendizábal s/n, 15403 Ferrol, SpainMODES Group, CITIC, Department of Mathematics, Faculty of Computer Science, Campus de Elviña, Universidade da Coruña, 15008 A Coruña, SpainMODES Group, CITIC, Department of Mathematics, Escola Politécnica Superior, Campus Industrial, Universidade da Coruña, Mendizábal s/n, 15403 Ferrol, SpainThis study proposes a control chart based on functional data to detect anomalies and estimate the normal output of industrial processes and services such as those related to the energy efficiency domain. Companies providing statistical consultancy services in the fields of energy efficiency; heating, ventilation and air conditioning (HVAC); installation and control; and big data for buildings, have been striving to solve the problem of automatic anomaly detection in buildings controlled by sensors. Given the functional nature of the critical to quality (CTQ) variables, this study proposed a new functional data analysis (FDA) control chart method based on the concept of data depth. Specifically, it developed a control methodology, including the Phase I and II control charts. It is based on the calculation of the depth of functional data, the identification of outliers by smooth bootstrap resampling and the customization of nonparametric rank control charts. A comprehensive simulation study, comprising scenarios defined with different degrees of dependence between curves, was conducted to evaluate the control procedure. The proposed statistical process control procedure was also applied to detect energy efficiency anomalies in the stores of a textile company in the Panama City. In this case, energy consumption has been defined as the CTQ variable of the HVAC system. Briefly, the proposed methodology, which combines FDA and multivariate techniques, adapts the concept of the control chart based on a specific case of functional data and thereby presents a novel alternative for controlling facilities in which the data are obtained by continuous monitoring, as is the case with a great deal of process in the framework of Industry 4.0.https://www.mdpi.com/2227-7390/8/1/58functional data analysisstatistical process controlcontrol chartdata depthnonparametric control chartenergy efficiency
spellingShingle Miguel Flores
Salvador Naya
Rubén Fernández-Casal
Sonia Zaragoza
Paula Raña
Javier Tarrío-Saavedra
Constructing a Control Chart Using Functional Data
Mathematics
functional data analysis
statistical process control
control chart
data depth
nonparametric control chart
energy efficiency
title Constructing a Control Chart Using Functional Data
title_full Constructing a Control Chart Using Functional Data
title_fullStr Constructing a Control Chart Using Functional Data
title_full_unstemmed Constructing a Control Chart Using Functional Data
title_short Constructing a Control Chart Using Functional Data
title_sort constructing a control chart using functional data
topic functional data analysis
statistical process control
control chart
data depth
nonparametric control chart
energy efficiency
url https://www.mdpi.com/2227-7390/8/1/58
work_keys_str_mv AT miguelflores constructingacontrolchartusingfunctionaldata
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AT rubenfernandezcasal constructingacontrolchartusingfunctionaldata
AT soniazaragoza constructingacontrolchartusingfunctionaldata
AT paularana constructingacontrolchartusingfunctionaldata
AT javiertarriosaavedra constructingacontrolchartusingfunctionaldata