Economic design method for variable sampling interval and sample capacity EWMA control chart under non-normal distribution

A technique of sample size and normal distribution, applied in computing, market forecasting, marketing, etc., which can solve problems such as skewness of observations and economic design of EWMA control charts that are not taken into account at the same time.

Inactive Publication Date: 2021-09-10
ZHENGZHOU UNIVERSITY OF AERONAUTICS
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Problems solved by technology

However, in practice, the assumption of normality may not be satisfied, and sometimes the observations will show skewness. When the process observations do not satisfy the assumption of normality, some scholars use the Burr distribution to approximate different situations to study non-normal distributions. ;
[0003] In the existing design methods of EWMA control charts, only the economic design of EWMA control charts with variable sampling interval (VSI) or variable sample size is considered, but the variable sampling interval in the case of non-normal distribution is not considered at the same time. The economic design problem of the EWMA control chart with sample size

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  • Economic design method for variable sampling interval and sample capacity EWMA control chart under non-normal distribution
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  • Economic design method for variable sampling interval and sample capacity EWMA control chart under non-normal distribution

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[0087] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0088] First, the economic design method of the VSSI non-state EWMA control diagram, which includes the following steps:

[0089] Step 1: Collect data. Using the data acquisition device to collect non-normal data in industrial production, and use X to indicate the observed value variable, the mean and standard differences of the observation value are μ and σ.

[0090] Step 2: Data Transformation. Since the distribution of data is unknown, it is necessary to determine the distribution function via the Burr change, set the BURR variable as Y, in the next step, the following conversion rules are taken between the variables x and y:

[0091] (1) The polarization coefficient of X is calculated by the following formula. 3 Peak factor alpha 4 :

[0092]

[0093] (4) Found with α in the BURR distribution table 3 Alpha 4 The corresponding Burr parameter C and Q (C and Q are constant greater than 1), thereby determining the corres...

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Abstract

The invention relates to an economic design method for a variable sampling interval and sample capacity EWMA control chart under non-normal distribution, and aims so solve the problem that, in the prior art, the economic design of an EWMA control chart considers a variable sampling interval (VSI) or a variable sample capacity (VSS), but the economic design of an EWMA control chart of a variable sampling interval and sample capacity (VSSI) under the condition of non-normal distribution is not considered at the same time. The invention provides a corresponding economic design method aiming at the complex situation and provides a detailed design flow. Through the design of the invention, the monitoring cost of a process can be reduced while the monitoring efficiency is improved, the unit time cost of the designed VSSI non-normal EWMA control chart economic model is expected to be smaller than that of VSI and VSS non-normal EWMA control charts in each group of experiments, and the economic optimality is realized.

Description

Technical field [0001] The present invention relates to the technical field of controlling map economy, and is specific to the economic design method of variable sampling interval and sample capacity EWMA control diagram under non-normal distribution. Background technique [0002] In the production process, statistical process control is an effective method for improving product production quality. With the increasing product quality and efficiency, the control map is widely used in production practice as an important tool for process control. The design is designed for the control diagram to provide settings for the parameters (sampling interval, sample capacity, control limits, etc.) of the control diagram to meet the established requirements. The design of the control diagram is called static design when the sampling parameters are constant. In order to improve the monitoring efficiency of the control diagram, some scholars have designed a dynamic control diagram of the variab...

Claims

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Application Information

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IPC IPC(8): G06Q10/04G06Q10/06G06Q30/02
CPCG06Q10/04G06Q10/067G06Q30/0206
Inventor 薛丽李聪凯曹逗逗贾元忠朱捷吴昊辰郑含笑
Owner ZHENGZHOU UNIVERSITY OF AERONAUTICS
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