In the manufacture of metal fasteners in a progressive die operation, and other industrial situations, important quality dimensions cannot be measured on a continuous scale, and parts are classified into groups using a step gauge. This article proposes a version of exponentially weighted moving average (EWMA) control charts applicable to monitoring the grouped data for process shifts. The run l...

A multivariate control chart is proposed to detect changes in the process dispersion of multiple correlated quality characteristics. We focus on individual observations, where we monitor data vector-by-vector rather than (rational) subgroups. The developed by applying logarithm diagonal elements estimated covariance matrix. Then, this vector incorporated an exponentially weighted moving average...

Abstract The objective of this research is to study numerical integral equation method (NIE) using five quadrature rules namely, composite midpoint rule, trapezoidal Simpson’s Boole’s rule and Gauss-Legendre for approximating the average run length on extended exponentially weighted moving (extended EWMA) control chart autoregressive process with explanatory variables when white noise follows a...

The exponentially weighted moving average (EWMA) control chart is a memory-type known to be more efficient in detecting small and moderate shifts the process parameter. double EWMA (DEWMA) an extension of that effective than latter detection small-to-moderate shifts. This paper proposes new distribution-free (or nonparametric) triple (TEWMA) based on Wilcoxon rank-sum (W) statistic improve abil...

The basic purpose of the economic design of the control charts is to find the optimum control charts parameters to minimize the process cost. In this paper, an R package, edcc (economic design of control charts), which provides a numerical method to find the optimum chart parameters is presented using the unified approach of the economic design. Also, some examples are given to illustrate how t...

In many count data sets, an item may have more than one defect that causes the item to be defective. The Poisson EWMA scheme cannot be used to monitor such defects. The geometric-Poisson exponentially weighted moving average (EWMA) chart has been shown to be an effective scheme to monitor the number of defects over time. In these applications, it is assumed that the process parameters are known...

the most well-known uni-arribute control chart used to monitor the number of nonconformities per unit is the shewhart type c-chart. in this paper, a new method is proposed in an attempt to reduce the false alarm rate in the c-chart. to do this, the decision on beliefs (dob) concept is first uti [1] corresponding author e-mail: [email protected]   lized to design an iterat...

Control charts are graphical tools widely used to monitor manufacturing processes to quickly detect any change in a process that may result in a change in product quality. The statistic plotted on a control chart is based on samples of n ≥ 1 observations (rational subgroups) that may be taken at regular sampling intervals. However, there are numerous practical applications using individual obse...

The EWMA quality control chart, and its multivariate version (MEWMA), may be designed to efficiently detect small shifts in the mean vector of a set of p quality characteristics of a production process. However, this work presents a method for the optimal design of the parameters of the MEWMA and EWMA charts to control processes where it is not convenient to detect small magnitude shifts and, a...

Control charts based on time between events (TBE) data have been shown to be useful for monitoring production or failure processes where defect or failure occurrence can be recorded over time. One type of TBE chart is set up with probability control limits, e.g. the Cumulative Quantity Control (CQC) chart and its extension CQC-r chart, which monitors the quantity inspected until the occurrence ...