scholarly journals Accuracy of Zero Inflated Generalized Poisson Exponentially Moving Average Control Chart

2021 ◽  
Vol 18 (1) ◽  
pp. 121-129
Author(s):  
L.M. JAMALUDDIN Al AFGANI
Keyword(s):  
Control Chart ◽  
Moving Average ◽  
Mean Value ◽  
Distributed Data ◽  
Generalized Poisson ◽  
Number Of Zeros ◽  
Ewma Control Chart ◽  
Before And After ◽  
Average Control ◽  
The Mean

The Zero-Inflated Generalized Poisson (ZIGP) distribution is a case-based distribution where the discrete data has a large number of zeros and an overdispersion occurs, i.e. the variance is greater than the mean value. The purpose of this study is to determine the Exponential Weight Moving Average (EWMA) control chart with the assumption that the data has a Zero-Inflated Generalized Poisson (ZIP) distribution. The results show that the ARL value of the ARL ZIGP EWMA control chart has better accuracy when compared to when using the ZIP EWMA control chart on ZIGP distributed data. This is indicated by the smaller ARL value compared to the ZIP EWMA control chart, namely when φ = 1.4, and φ = 0.6. So that the ARL ZIGP EWMA control chart has a fairly good accuracy in detecting out of control conditions for ZIGP distributed data. In addition, the modified ARL shows the same values ​​before and after the modification for the underdispersion data and shows a larger or negative value for the overdispersion data. This can eliminate or reduce errors in analyzing the accuracy of the control chart.  

CV Control Chart Using GWMA Technique

2011 ◽  
Vol 337 ◽  
pp. 247-254 ◽  
Author(s):  
Eui Pyo Hong ◽  
Hae Woon Kang ◽  
Chang Wook Kang ◽  
Jae Won Baik
Keyword(s):  
Control Chart ◽  
Control Charts ◽  
Moving Average ◽  
Exponentially Weighted Moving Average ◽  
Average Technique ◽  
Ewma Control Chart ◽  
Production Run ◽  
Average Control ◽  
Weighted Moving Average ◽  
Exponentially Weighted

When the production run is short and process parameters change frequently, it is difficult to monitor the process using traditional control charts. In such a case, the coefficient of variation (CV) is very useful for monitoring the process variability. The CV control chart, however, is not sensitive at small shifts in the magnitude of CV. This study suggest the CV-GWMA(generally weighted moving average) control chart, combining the GWMA technique, which shows better performance than the EWMA(exponentially weighted moving average) or DEWMA(double exponentially weighted moving average) technique in detecting small shifts of the process. Through a performance evaluation, the proposed control chart showed more excellent performance than the existing CV-EWMA control chart or the CV-DEWMA control chart in detecting small shifts in CV.

scholarly journals An EWMA control chart for the mean of individual streams in multiple stream processes

2021 ◽  
Vol 28 (3) ◽  
Author(s):  
Bruno Francisco Teixeira Simões ◽  
Eugenio Kahn Epprecht
Keyword(s):  
Control Chart ◽  
Individual Component ◽  
Moving Average ◽  
Optimal Designs ◽  
Additional Contribution ◽  
Statistical Control ◽  
Ewma Control Chart ◽  
The Mean ◽  
The Individual ◽  
Weighted Moving Average

Abstract: In a multiple stream process (MSP) a product is manufactured in a number of streams in parallel. The traditional tool for monitoring MSPs, the group control chart (GCC), does not take into account that typically the value of the quality variable in each stream is the sum of a component common to all streams and an individual component, of the particular stream. This may render the GCC ineffective in detecting shifts in the mean of individual streams. Based on this two-components model, we propose an exponentially weighted moving average (EWMA) GCC to monitor the means of the individual streams components. We optimize its design (minimizing the ARL for given shifts in the mean of a stream) and compare their ARLs with the ones of other existing charts devised for two-components MSPs. For this comparison, we needed to obtain optimal designs of these previous charts too, which were not available in the literature; this is an additional contribution of our work. The ARLs of the charts were obtained by simulation, with a number of runs sufficiently large to ensure precise results. The results show that the proposed chart outperforms the previous ones, becoming thus recommended for the statistical control of MSPs.

scholarly journals NEW APPROACH FOR DETECTING SLIGHT SHIFT ON PROCESS MEAN IN CHIP RESISTOR PRODUCTION

2021 ◽  
Vol 56 (5) ◽  
pp. 59-66
Author(s):  
Budi Susetyo ◽  
Anwar Fitrianto ◽  
Lai Ming Choon
Keyword(s):  
Control Chart ◽  
Control Charts ◽  
Normal Population ◽  
Moving Average ◽  
Distributed Data ◽  
Process Mean ◽  
New Approach ◽  
Parametric Control ◽  
Ewma Control Chart ◽  
Alternative Approach

This article highlights an alternative approach to identify a slight shift of the process mean for resistor production. Commonly, the industries use exponentially weighted moving average (EWMA) or classic I-MR charts for this kind of product. The parametric control chart consists of few underlying assumptions, especially observations that come from a normal distribution. A misleading conclusion was mainly made when non-normal distributed data were analyzed using a parametric control chart. A chip resistor manufacturing company provided the data for the study for future quality monitoring purposes. This study aims to determine a more appropriate analysis method according to the characteristics of the chip resistor data distribution. This article discusses the results of implementing one of the nonparametric methods that are still rarely known. The company’s current I-MR, corrective I-MR, parametric EWMA, and NPEWMA-SR control charts are used and compared in the analysis part. In the comparison, the I-MR control chart cannot detect a slight shift in the process mean. In contrast, the parametric EWMA control chart is not robust for data from a non-normal population. Since the data was not naturally from a normally distributed population, the nonparametric control chart is more appropriate, and the NPEWMA-SR control chart is suggested.

Perbedaan Pengetahuan Siswa Tentang Penyakit Hepatitis A Sebelum Dan Sesudah Penyuluhan Di MTsN 02 Bondowoso Tahun 2015

2017 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Putri Megasari
Keyword(s):  
Hepatitis A ◽  
Hepatitis Virus ◽  
Sampling Technique ◽  
Mean Value ◽  
Test Design ◽  
The World ◽  
Before And After ◽  
Post Test ◽  
The Mean ◽  
Paired T Test

Hepatitis has become a health problem in the world. The hepatitis virus infected many people. According to the teacher of MTsN 02 Bondowoso more than 20 students have hepatitis A viral infection. The purpose of this research was to know the differences of students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study used pre-experimental (pre-post test design). This study used stratified random sampling technique, 127 students from 270 sample involved this research,and 143 students was excluded. We used questionnaires to collect data. The results showed that the mean value of the students 'knowledge about hepatitis A before counseling in MTsN 02 Bondowoso 2015 was 83.96 with the lowest value of 37.5 and the highest value was 100. The mean value of the students' knowledge about hepatitis A after counseling in MTsN 02 Bondowoso 2015 was 93.21 with the lowest value waf 62.5 and the highest value was 100. Paired t test showed that t (-9.07) > t table (1.98), the null hypothesis (H0) was rejected. There was a difference between students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study showed that routine counseling by healthcare provider was important to prevent hepatitis A infection.; Keywords: counseling, knowledge of students, hepatitis

scholarly journals Quality of life of obstetrics fistula patients before and after surgical repair in the Jimma University Medical Center, Southwest Ethiopia

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Tilahun Fufa Debela ◽  
Zerihun Asefa Hordofa ◽  
Aster Berhe Aregawi ◽  
Demisew Amenu Sori
Keyword(s):  
Quality Of Life ◽  
Surgical Repair ◽  
Obstetric Fistula ◽  
Medical Center ◽  
Mean Value ◽  
Significant Difference ◽  
Before And After ◽  
The Mean ◽  
Jimma University

Abstract Background The consequences of obstetric fistula on affected women are more than the medical condition. It has extensive physical, psychological, social, and economic consequences on them. Obstetric fistula affects the entire health and entire life of women. Women suffering from obstetric fistula are often abandoned by her partner, relatives, and the community. This study aimed to determine the quality of life of obstetrics fistula patients before and after surgical repair. Methods Institutional-based prospective, before and after study design was conducted in the Jimma University Medical Center from November 1, 2019–October 30, 2020. A face-to-face interview was conducted with fistula patients who visited Jimma University Medical center, fistula clinic during the study period. All fistula patients were included in the study. Accordingly, 78 women who underwent surgical repair were interviewed. The means and the standard deviation were computed using conventional statistics formulas. The unpaired t-test was used to compare two independent means, and one-way analysis of variance (ANOVA) was used to compare the quality of life before repair and after a successful repair. Linear regression analysis was done for identifying determinants of quality of life. A P value of 0.05 will be considered statistical significance. Result The overall quality of life of women was 58.17 ± 7.2 before the surgical repair and 71.20 ± 10.79 after surgical repair. The result indicates there is a significant difference in the mean value of pre and post-operative (P < 0.001). The overall satisfaction of women with their health status before the surgical repair was 22.5 ± 1.30and it has increased to 53.0 ± .90after surgical repair. The physical health dimension score was 16.51 ± 5.27 before the surgical repair while it has increased to 21.77 ± 5.38 after the surgical repair. The score of the social domain before the surgical repair was 5.19 ± 1.34 and it has increased to 7.13 ± 3.67 after the surgical repair. The score of the environmental health domain was 17.41 ± 2.89 before the surgery while it also increased to 21.65 ± 4.04 after the surgical repair. The results have shown there was a significant difference in the mean values of pre and post-operatives in both social and environmental scores (P < 0.001). The score of the psychological health domain before the surgery was 19.06 ± 1.46 and it was increased to 19.84 ± 3.21 after the surgical repair. The result showed there is a significant difference in mean value pre and post-operative (P = 0.048), though it is a slight improvement compared to other domains. Conclusion The overall quality of life of the patient with fistula was improved after successful surgical repair. Although all domains of quality of life had shown significant improvement after successful surgical repair, the psychological domain showed slight improvement.

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