This article develops a new distribution-free multivariate procedure for statisticalprocesscontrol based on minimal spanning tree (MST), which integrates a multivariate two-sample goodness-of-fit (GOF) test based on...
详细信息
This article develops a new distribution-free multivariate procedure for statisticalprocesscontrol based on minimal spanning tree (MST), which integrates a multivariate two-sample goodness-of-fit (GOF) test based on MST and change-point model. Simulation results show that our proposed procedure is quite robust to nonnormally distributed data, and moreover, it is efficient in detecting process shifts, especially moderate to large shifts, which is one of the main drawbacks of most distribution-free procedures in the literature. The proposed procedure is particularly useful in start-up situations. Comparison results and a real data example show that our proposed procedure has great potential for application.
In multivariate statistical process control, when a process shift occurs, not all variables but a few variables may shift from the in-control state. This paper proposes a multivariate EWMA control chart based on a var...
详细信息
In multivariate statistical process control, when a process shift occurs, not all variables but a few variables may shift from the in-control state. This paper proposes a multivariate EWMA control chart based on a variable selection using AIC. (C) 2015 Elsevier B.V. All rights reserved.
Poultry meat industry requires intelligent systems for achieving non-invasive real-time detection of bone fragments. Therefore, the main aim of this study was to assess the feasibility of using ultrasound imaging and ...
详细信息
Poultry meat industry requires intelligent systems for achieving non-invasive real-time detection of bone fragments. Therefore, the main aim of this study was to assess the feasibility of using ultrasound imaging and multivariate image analysis to detect bone fragments in boneless and skinless chicken breast fillets. Bone fragments of different sizes were inserted into the chicken and contact ultrasound images were acquired, following a pre-established pattern, in the control (C) and out-control (OC, with bone) samples, by scanning the breast's surface, using contact ultrasound sensors (1 MHz) working in through transmission. Energy-magnitude and energy-distribution ultrasound parameters were computed at pixel level in time (TDA) and frequency domain (FDA). Principal Component Analysis (PCA) was used in TDA and FDA parameters, and its combination (TFDA). From PCA model, the Residual Sum Squares (RSS) and Hotelling's T-square (T-2) control statistics were used to classify the C and OC images projected on the PCA latent structure. Experimental results demonstrated that the presence of bone fragments within chicken breast fillets led to alterations in the energy-magnitude (avg. amplitude decrease from 81.6 % to 52.6 %, depending on the bone size) and energy-distribution ultrasound parameters (avg. variance decreased from 97.9 % to 70.6 % depending on the bone size). The RSS statistic achieved the best classification performance (accuracy of TDA, FDA and TFDA>95 %) in C and OC images. These results highlight the potential of combining contact ultrasound imaging with multivariate image analysis for the reliable and rapid detection of bone fragments in chicken breasts.
In the domain of rotating machinery, bearings are vulnerable to different mechanical faults, including ball, inner, and outer race faults. Various techniques can be used in condition-based monitoring, from classical s...
详细信息
In the domain of rotating machinery, bearings are vulnerable to different mechanical faults, including ball, inner, and outer race faults. Various techniques can be used in condition-based monitoring, from classical signal analysis to deep learning methods in diagnosing these faults. Based on the complex working conditions of rotary machines, multivariate statistical process control charts such as Hotelling's T2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$T<^>multivariate$\end{document} and Squared Prediction Error are useful for providing early warnings. However, these methods are rarely applied to condition monitoring of rotating machinery due to the univariate nature of the datasets. In the present paper, we propose a multivariate statistical process control-based fault detection method that utilizes multivariate data composed of Fourier transform features that are extracted for fixed-time batches. Our approach makes use of the multidimensional nature of Fourier transform characteristics, which record more detailed information about the machine's status, in an effort to enhance early defect detection and diagnosis. Experiments with varying vibration measurement locations (Fan End, Drive End), fault types (ball, inner, and outer race faults), and motor loads (0-3 horsepower) are used to validate the suggested approach. The outcomes illustrate our method's effectiveness in fault detection and point to possible wider uses in industrial maintenance.
In multivariate statistical process control (MSPC), most multivariatecontrol charts can effectively monitor anomalies based on overall statistic, however, they cannot provide guidelines to classify the source(s) of o...
详细信息
In multivariate statistical process control (MSPC), most multivariatecontrol charts can effectively monitor anomalies based on overall statistic, however, they cannot provide guidelines to classify the source(s) of out-of-control signals. Classifying the source(s) of process mean shifts is critical for quality control in multivariate manufacturing process since the immediate identification of them can greatly help quality engineer to narrow down the set of possible root causes and take corrective actions. This study presents an improved particle swarm optimisation with simulated annealing-based selective multiclass support vector machines ensemble (PS-SVME) approach, in which some selective multiclass SVMs are jointly used for classifying the source(s) of process mean shifts in multivariatecontrol charts. The performance of the proposed PS-SVME approach is evaluated by computing its classification accuracy. Simulation experiments are conducted and a real application is illustrated to validate the effectiveness of the developed approach. The analysis results indicate that the developed PS-SVME approach can perform effectively for classifying the source(s) of process mean shifts.
This paper describes a proposed framework for multivariateprocesscontrol chart recognition. The proposed methodology uses the Artificial Neural Networks (ANNs) to recognize set of subclasses of multivariate abnormal...
详细信息
This paper describes a proposed framework for multivariateprocesscontrol chart recognition. The proposed methodology uses the Artificial Neural Networks (ANNs) to recognize set of subclasses of multivariate abnormal patterns. identify the responsible variable(s) oil the occurrence of abnormal pattern and classify the abnormal pattern parameters. The performance of the proposed approach has been evaluated using a real case study. The numerical and graphical results are presented which demonstrate that the approach performs effectively in control chart multivariate pattern recognition. In addition. accurately identifies and classifies the parameters of the errant variable(s). (C) 2009 Published by Elsevier Ltd
Variability in manufacturing processes must be properly monitored and controlled to avoid incurring quality problems;otherwise, the probability of manufacturing defective products increases, and, consequently, product...
详细信息
Variability in manufacturing processes must be properly monitored and controlled to avoid incurring quality problems;otherwise, the probability of manufacturing defective products increases, and, consequently, production costs rise. This paper presents the development of a methodology to locate the source(s) of variation in the manufacturing process in case of a statistical deviation so that the user can quickly take corrective actions to eliminate the source of variation, thus avoiding the manufacture of out-of-specification products. The methodology integrates the multivariate cumulative sum control chart and the multilayer perceptron artificial neural network for the detection and interpretation of the source(s) of variation generated in the manufacturing processes. A case study was carried out with a printed circuit board manufacturing process, and it was possible to classify the origin of the variation with a sensitivity of 92.41% and specificity of 91.16%. The results demonstrate the viability of the proposed methodology to monitor and interpret the source of statistical variation present in production systems.
multivariate statistical process control (MSPC) is applied to an electrolysis process. The process produces extremely pure copper, and to monitor its quality the levels of eight metal impurities were recorded twice a ...
详细信息
multivariate statistical process control (MSPC) is applied to an electrolysis process. The process produces extremely pure copper, and to monitor its quality the levels of eight metal impurities were recorded twice a day. These quality data are analysed adopting an (1) 'intuitive' univariate approach, and (2) with multivariate techniques. It is demonstrated that the univariate analysis gives confusing results with regards to outlier detection, while the multivariate approach identifies two types of outliers. Moreover, it is shown how the results from the multivariate principal component analysis (PCA) method can be displayed graphically in multivariatecontrol charts, multivariate Shewhart, cumulative sum (CUSUM) and exponentially weighted moving average (EWMA) control charts are used and compared. Also, an informationally powerful control chart, the simultaneous scores monitoring and residual tracking (SMART) chart, is introduced and used. (C) 1998 Elsevier Science B.V. All rights reserved.
process analytical technology is an essential step forward in pharmaceutical industry. Real-time analyzers will provide timely data on quality properties. This information combined with process data (temperatures, flo...
详细信息
process analytical technology is an essential step forward in pharmaceutical industry. Real-time analyzers will provide timely data on quality properties. This information combined with process data (temperatures, flow rates, pressure readings) collected in real time can become a powerful tool for this industry, for process understanding, process and quality monitoring, abnormal situation detection and for improving product quality and process reliability. A very important tool for this achievement is the multivariate analysis.
The quality of a product is dynamic in nature and develops over time. We present a case study from the food industry in which the concept of measuring the end-product quality is extended to incorporate the shelf-life ...
详细信息
The quality of a product is dynamic in nature and develops over time. We present a case study from the food industry in which the concept of measuring the end-product quality is extended to incorporate the shelf-life period of the product with practical examples showing the harm of ignoring the changes that occur in the product quality as a function of time. The article also addresses the use of in-line spectroscopy to relate the variations in the input parameters, such as the raw materials, and the process variables to the final product quality over the entire shelf-life of the product. We also discuss multivariate statistical process control and monitoring issues.
暂无评论