493 research outputs found

    Multivariate Statistical Process Control Charts: An Overview

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    In this paper we discuss the basic procedures for the implementation of multivariate statistical process control via control charting. Furthermore, we review multivariate extensions for all kinds of univariate control charts, such as multivariate Shewhart-type control charts, multivariate CUSUM control charts and multivariate EWMA control charts. In addition, we review unique procedures for the construction of multivariate control charts, based on multivariate statistical techniques such as principal components analysis (PCA) and partial lest squares (PLS). Finally, we describe the most significant methods for the interpretation of an out-of-control signal.quality control, process control, multivariate statistical process control, Hotelling's T-square, CUSUM, EWMA, PCA, PLS

    A review on the influence of drinking water quality towards human health

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    An adequate supply of safe drinking water is one of the major prerequisites for a healthy life. Inadequate of safe drinking water produce waterborne disease and a major cause of death in many parts of the world, particularly in children. Therefore, it must be treated properly before it can be used and consumed. This chapter provides the guidelines of important parameters for drinking water standard in order to ensure the safeness of drinking water. All the selected parameters were elaborated on the effect of high concentration if human consume the drinking water directly

    Multivariate Statistical Process Control Charts: An Overview

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    In this paper we discuss the basic procedures for the implementation of multivariate statistical process control via control charting. Furthermore, we review multivariate extensions for all kinds of univariate control charts, such as multivariate Shewhart-type control charts, multivariate CUSUM control charts and multivariate EWMA control charts. In addition, we review unique procedures for the construction of multivariate control charts, based on multivariate statistical techniques such as principal components analysis (PCA) and partial lest squares (PLS). Finally, we describe the most significant methods for the interpretation of an out-of-control signal

    Practical Concepts of Quality Control

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    This book aims to provide a concise account of the essential elements of quality control. It is designed to be used as a text for courses on quality control for students of industrial engineering at the advanced undergraduate, or as a reference for researchers in related fields seeking a concise treatment of the key concepts of quality control. It is intended to give a contemporary account of procedures used to design quality models

    A framework for automation of data recording, modelling, and optimal statistical control of production lines

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    Unarguably, the automation of data collection and subsequent statistical treatment enhance the quality of industrial management systems. The rise of accessible digital technologies has enabled the introduction of the Industry 4.0 pillars in Cariri local companies. Particularly, such practice positively contributes to the triple bottom line of sustainable development: People, Environment, and Economy. The present work aims to provide a general automated framework for data recording and statistical control of conveyor belts in production lines. The software has been developed in three layers: graphical user interface, in PHP language; database collection, search, and safeguard, in MySQL; computational statistics, in R; and hardware control, in C. The computational statistics are based on the combination of artificial neural nets and autoregressive integrated and moving average models, via minimal variance method. The hardware components are composed by open source hardware as Arduino based boards and modular or industrial sensors. Specifically, the embedded system is designed to constantly monitor and record a number of measurable characteristics of the conveyor belts (e.g. electric consumption and temperature), via a number of sensors, allowing both the computation of statistical control metrics and the evaluation of the quality of the production system. As a case study, the project makes use of a laminated limestone production line, located at the Mineral Technology Center, Nova Olinda, Ceará state, Brazil.Indiscutivelmente, a automação da coleta de dados e o subsequente tratamento estatístico aumentam a qualidade dos sistemas de gestão industrial. O surgimento de tecnologias digitais acessíveis possibilitou a introdução dos pilares da Indústria 4.0 nas empresas locais do Cariri. Particularmente, tal prática contribui positivamente para o triplo resultado do desenvolvimento sustentável: Pessoas, Meio Ambiente e Economia. O presente trabalho tem como objetivo fornecer um Framework geral automatizado para registro de dados e controle estatístico de esteiras transportadoras em linhas de produção. O software foi desenvolvido em três camadas: interface gráfica do usuário, em linguagem PHP; coleta, pesquisa e proteção de banco de dados em MySQL; estatística computacional, em R; e controle de hardware, em C. As estatísticas computacionais são baseadas na combinação de redes neurais artificiais e modelos autorregressivos integrados e de média móvel, via método de mínima variância. Os componentes de hardware são compostos por hardware open source como placas baseadas em Arduino e sensores modulares ou industriais. Especificamente, o sistema embarcado é projetado para monitorar e registrar constantemente uma série de características mensuráveis das esteiras transportadoras (por exemplo, consumo elétrico e temperatura), por meio de uma série de sensores, permitindo tanto o cálculo de métricas de controle estatístico quanto a avaliação da qualidade do sistema de produção. Como estudo de caso, o projeto utiliza uma linha de produção de calcário laminado, localizada no Centro de Tecnologia Mineral, Nova Olinda, Ceará, Brasil

    Spatiotemporal Wireless Sensor Network Field Approximation with Multilayer Perceptron Artificial Neural Network Models

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    As sensors become increasingly compact and dependable in natural environments, spatially-distributed heterogeneous sensor network systems steadily become more pervasive. However, any environmental monitoring system must account for potential data loss due to a variety of natural and technological causes. Modeling a natural spatial region can be problematic due to spatial nonstationarities in environmental variables, and as particular regions may be subject to specific influences at different spatial scales. Relationships between processes within these regions are often ephemeral, so models designed to represent them cannot remain static. Integrating temporal factors into this model engenders further complexity. This dissertation evaluates the use of multilayer perceptron neural network models in the context of sensor networks as a possible solution to many of these problems given their data-driven nature, their representational flexibility and straightforward fitting process. The relative importance of parameters is determined via an adaptive backpropagation training process, which converges to a best-fit model for sensing platforms to validate collected data or approximate missing readings. As conditions evolve over time such that the model can no longer adapt to changes, new models are trained to replace the old. We demonstrate accuracy results for the MLP generally on par with those of spatial kriging, but able to integrate additional physical and temporal parameters, enabling its application to any region with a collection of available data streams. Potential uses of this model might be not only to approximate missing data in the sensor field, but also to flag potentially incorrect, unusual or atypical data returned by the sensor network. Given the potential for spatial heterogeneity in a monitored phenomenon, this dissertation further explores the benefits of partitioning a space and applying individual MLP models to these partitions. A system of neural models using both spatial and temporal parameters can be envisioned such that a spatiotemporal space partitioned by k-means is modeled by k neural models with internal weightings varying individually according to the dominant processes within the assigned region of each. Evaluated on simulated and real data on surface currents of theGulf ofMaine, partitioned models show significant improved results over single global models

    Short Production Run Control Charts to Monitor Process Variances

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    Control chart is one of the most commonly used statistical tools for quality control and improvement. If the process mean and standard deviation are not given or unknown, most Shewhart control charts require sufficient sample data before the control chart can be established. However, in certain industries or processes, it may not be practical to collect adequate amount of data at the beginning of the manufacturing process to build the trial control chart in Phase I. For quality improvement in such or similar processes, some authors developed self-starting control charts for short-run production, e.g. t chart, Q chart, EWMA t chart/Q chart, CUSUM t chart/Q chart. This thesis studies the performance of some short run control charts for monitoring process variances. Numerical simulations are using in this study. The results of the numerical experiments are extensively tested for different combinations of process lengths and starting points of process shifts

    ISBIS 2016: Meeting on Statistics in Business and Industry

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    This Book includes the abstracts of the talks presented at the 2016 International Symposium on Business and Industrial Statistics, held at Barcelona, June 8-10, 2016, hosted at the Universitat Politècnica de Catalunya - Barcelona TECH, by the Department of Statistics and Operations Research. The location of the meeting was at ETSEIB Building (Escola Tecnica Superior d'Enginyeria Industrial) at Avda Diagonal 647. The meeting organizers celebrated the continued success of ISBIS and ENBIS society, and the meeting draw together the international community of statisticians, both academics and industry professionals, who share the goal of making statistics the foundation for decision making in business and related applications. The Scientific Program Committee was constituted by: David Banks, Duke University Amílcar Oliveira, DCeT - Universidade Aberta and CEAUL Teresa A. Oliveira, DCeT - Universidade Aberta and CEAUL Nalini Ravishankar, University of Connecticut Xavier Tort Martorell, Universitat Politécnica de Catalunya, Barcelona TECH Martina Vandebroek, KU Leuven Vincenzo Esposito Vinzi, ESSEC Business Schoo

    A DATA ANALYTICAL FRAMEWORK FOR IMPROVING REAL-TIME, DECISION SUPPORT SYSTEMS IN HEALTHCARE

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    In this dissertation we develop a framework that combines data mining, statistics and operations research methods for improving real-time decision support systems in healthcare. Our approach consists of three main concepts: data gathering and preprocessing, modeling, and deployment. We introduce the notion of offline and semi-offline modeling to differentiate between models that are based on known baseline behavior and those based on a baseline with missing information. We apply and illustrate the framework in the context of two important healthcare contexts: biosurveillance and kidney allocation. In the biosurveillance context, we address the problem of early detection of disease outbreaks. We discuss integer programming-based univariate monitoring and statistical and operations research-based multivariate monitoring approaches. We assess method performance on authentic biosurveillance data. In the kidney allocation context, we present a two-phase model that combines an integer programming-based learning phase and a data-analytical based real-time phase. We examine and evaluate our method on the current Organ Procurement and Transplantation Network (OPTN) waiting list. In both contexts, we show that our framework produces significant improvements over existing methods
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