statistical control
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Author(s):  
Adriana E. BOERIU ◽  
◽  
Cristina M. CANJA ◽  

Zero defects or nearly zero faulty products production process represents a new and important concern towards quality control of production systems. The requirement of a pertinent statistical control is important for identifying and monitoring defects, the main source of defects that occur in industrial bread making process. The current study was focused on applying two analysis methods Failure Mode and Effects Analyses, abbreviated FMEA and Pareto. Analysis concerning two technological stages that were considered as having a major impact on the quality of the final products. It was observed that the percent of nonconformities decreased in a significant manner – from 30% in 2018 to 5% in 2019 by applying the FMEA analysis. Also, the Pareto diagram showed that the application of several corrective measurements conducted to important decreases of Risk Priority Number from 288 to 128 and the severity decreased from 8 to 5 in the mixing process and from 128 to 81 for the baking process.


Author(s):  
Roxana González Álvarez ◽  
Aníbal Barrera García ◽  
Ana Beatriz Guerra Morffi ◽  
Juan Felipe Medina Mendieta

Statistical quality control is a set of tools and techniques that allows to verify, monitor and control the variability of processes to improve product quality and business competitiveness. The objective of this study was to evaluate the pasta production process of a company that belongs to the food industry sector in terms of stability and compliance of quality specifications. The Six Sigma improvement methodology was used, which focuses on identifying and eliminating the causes of variation in the processes. Data collection was accomplished by the use of different techniques, such as: interviews, brainstorming, review of documents, teamwork and direct observation. In addition, process documentation techniques and classical quality tools including Pareto chart, control charts, process capability analysis, histogram, Ishikawa diagram and experimental design were used. Multivariate data reduction techniques were also applied. The results showed for the quality characteristic Humidity that the process is out of statistical control and it is uncapable to meet the required specifications, for which the causes were investigated and improvement actions were proposed, achieving an increase in the sigma quality level.


Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7524
Author(s):  
Rubén Moliner-Heredia ◽  
Gracia M. Bruscas-Bellido ◽  
José V. Abellán-Nebot ◽  
Ignacio Peñarrocha-Alós

Fault diagnosis in multistage manufacturing processes (MMPs) is a challenging task where most of the research presented in the literature considers a predefined inspection scheme to identify the sources of variation and make the process diagnosable. In this paper, a sequential inspection procedure to detect the process fault based on a sequential testing algorithm and a minimum monitoring system is proposed. After the monitoring system detects that the process is out of statistical control, the features to be inspected (end of line or in process measurements) are defined sequentially according to the expected information gain of each potential inspection measurement. A case study is analyzed to prove the benefits of this approach with respect to a predefined inspection scheme and a randomized sequential inspection considering both the use and non-use of fault probabilities from historical maintenance data.


2021 ◽  
pp. 004912412110431
Author(s):  
Minghui Yao ◽  
Yunjie (Calvin) Xu

As a crucial method in organizational and social behavior research, self-report surveys must manage method bias. Method biases are distorted scores in survey response, distorted variance in variables, and distorted relational estimates between variables caused by method designs. Studies on method bias have focused on post hoc statistical control, but integrated analyses of the sociopsychological mechanism of method bias are lacking. This review proposes a framework for method bias and offers a relatively complete and detailed review of the sociopsychological and statistical mechanisms of four main types of method bias and their procedural remedies. This review proposes “reduce, remove, and rectify” as a guideline for researchers in survey design to address method bias. Finally, this review presents two directions for future methodology research.


2021 ◽  
Author(s):  
Romain Coulon

This chapter aims to emphasize the issue of the long-term stability of instruments used in metrology. This issue is a concern mentioned in the IEC/ISO17025:2017 standard and the JCGM100:2008 guide. Control charts are mentioned in these key documents as tools to assess whether a measurement process is under statistical control or not. Control charts (Shewhart charts, CUSUM chart, EWMA chart) are introduced and tested with simulated and real datasets from metrology instruments that operate at the ionizing department of the BIPM. The interest and the limits of such statistical analysis are discussed. They take their basis in a measurement model composed of Gaussian white noise. Although a measurement monitored over a relatively short period may be consistent with this model, it has been observed that the autocorrelation of the measurement data acquired over a long period limits the relevance of control charts. In this case, time series analysis seems more appropriate than conventional control charts. As an illustration, an optimal Bayesian smoother is introduced to demonstrate how to deconvolve the low-frequency random noise and refine the evaluation of uncertainty according to the measurement model for long-term measurement.


2021 ◽  
Vol 8 (11) ◽  
Author(s):  
Malte Wöstmann ◽  
Julia Erb ◽  
Jens Kreitewolf ◽  
Jonas Obleser

Acoustic noise is pervasive in human environments. Some individuals are more tolerant to noise than others. We demonstrate the explanatory potential of Big-5 personality traits neuroticism (being emotionally unstable) and extraversion (being enthusiastic, outgoing) on subjective self-report and objective psycho-acoustic metrics of hearing in noise in two samples (total N = 1103). Under statistical control for demographics and in agreement with pre-registered hypotheses, lower neuroticism and higher extraversion independently explained superior self-reported noise resistance, speech-hearing ability and acceptable background noise levels. Surprisingly, objective speech-in-noise recognition instead increased with higher levels of neuroticism. In turn, the bias in subjectively overrating one's own hearing in noise decreases with higher neuroticism but increases with higher extraversion. Of benefit to currently underspecified frameworks of hearing in noise and tailored audiological treatments, these results show that personality explains inter-individual differences in coping with acoustic noise, which is a ubiquitous source of distraction and a health hazard.


2021 ◽  
Author(s):  
Kerry A Ramsbottom ◽  
Ananth A Prakash ◽  
Yasset Perez-Riverol ◽  
Oscar Martin Camacho ◽  
Maria Martin ◽  
...  

Phosphoproteomics methods are commonly employed in labs to identify and quantify the sites of phosphorylation on proteins. In recent years, various software tools have been developed, incorporating scores or statistics related to whether a given phosphosite has been correctly identified, or to estimate the global false localisation rate (FLR) within a given data set for all sites reported. These scores have generally been calibrated using synthetic data sets, and their statistical reliability on real datasets is largely unknown. As a result, there is considerable problem in the field of reporting incorrectly localised phosphosites, due to inadequate statistical control. In this work, we develop the concept of using scoring and ranking modifications on a decoy amino acid, i.e. one that cannot be modified, to allow for independent estimation of global FLR. We test a variety of different amino acids to act as the decoy, on both synthetic and real data sets, demonstrating that the amino acid selection can make a substantial difference to the estimated global FLR. We conclude that while several different amino acids might be appropriate, the most reliable FLR results were achieved using alanine and leucine as decoys, although we have a preference for alanine due to the risk of potential confusion between leucine and isoleucine amino acids. We propose that the phosphoproteomics field should adopt the use of a decoy amino acid, so that there is better control of false reporting in the literature, and in public databases that re-distribute the data.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yi Yang ◽  
Guoquan Yan ◽  
Siyuan Kong ◽  
Mengxi Wu ◽  
Pengyuan Yang ◽  
...  

AbstractLarge-scale profiling of intact glycopeptides is critical but challenging in glycoproteomics. Data independent acquisition (DIA) is an emerging technology with deep proteome coverage and accurate quantitative capability in proteomics studies, but is still in the early stage of development in the field of glycoproteomics. We propose GproDIA, a framework for the proteome-wide characterization of intact glycopeptides from DIA data with comprehensive statistical control by a 2-dimentional false discovery rate approach and a glycoform inference algorithm, enabling accurate identification of intact glycopeptides using wide isolation windows. We further utilize a semi-empirical spectrum prediction strategy to expand the coverage of spectral libraries of glycopeptides. We benchmark our method for N-glycopeptide profiling on DIA data of yeast and human serum samples, demonstrating that DIA with GproDIA outperforms the data-dependent acquisition-based methods for glycoproteomics in terms of capacity and data completeness of identification, as well as accuracy and precision of quantification. We expect that this work can provide a powerful tool for glycoproteomic studies.


2021 ◽  
Vol 21 (4) ◽  
pp. 256-265
Author(s):  
I. A. Alekseeva ◽  
O. V. Perelygina ◽  
E. D. Kolyshkina

The Russian Federation puts special emphasis on vaccination-related issues, in accordance with the WHO recommendations. The fact that vaccination, in particular with the diphtheria, tetanus, and pertussis vaccine (DTP vaccine), covers large population groups, accounts for the relevance of research aimed at improving the quality of vaccines. One of the ways to produce vaccines of assured quality is to maintain consistent manufacturing processes that ensure consistency of product characteristics. The stability of the technological processes may be assessed using Shewhart charts. The aim of the study was to assess the production consistency of diphtheria, tetanus, and pertussis components of DTP vaccine using Shewhart control charts. Materials and methods: the study used data from 60 batch summary protocols of a Russian-produced DTP vaccine that were submitted to the Testing Centre of the Scientific Centre for Expert Evaluation of Medicinal Products from September 2017 until April 2020. The study assessed one of the main vaccine quality characteristics—specific (protective) activity of diphtheria, tetanus, and pertussis components. Shewhart charts for the diphtheria and tetanus components were constructed based on the manufacturer’s summary protocols, while Shewhart charts for the pertussis component were constructed based on both summary protocols and the results obtained by the Testing Centre during certification of the product batches. The Shewhart charts were used in accordance with the national standards GOST R 50779.42-99 and GOST R ISO 7870-2-2015. Results: a retrospective analysis of R- and X-charts covering a 2.5-year period revealed some characteristic trends in special-cause criteria. The most alarming situation was observed for the production of the diphtheria component. The technological processes were somewhat safer in the case of the tetanus and pertussis components. The production process lacked due statistical control, which is confirmed by the lack of correlation between the results of the pertussis component activity assessment obtained by the manufacturer and the Testing Centre. Conclusions: during the analysed period, the production of the diphtheria, tetanus, and pertussis components of the DTP vaccine was not always consistent. This highlights the need to conduct research aimed at standardisation of both production processes and control test conditions.


2021 ◽  
Author(s):  
Katie Logos ◽  
neil brewer ◽  
Robyn L. Young

Verbal intelligence—which relates to memory performance, abstract reasoning, and g—is often important to account for within psychological research. However, the time demands and financial costs associated with researcher-administered testing using valid measures of intelligence limit researchers’ ability to include such measures within their research. To address this issue, we examined the convergent validity of two tests of verbal intelligence that could be self-administered online with the well-validated Wechsler Abbreviated Scale of Intelligence–Second Edition (WASI-II). An undergraduate sample of participants (N = 104) completed the Self-Administered Verbal IQ Test (SA-VIQT), with a subsection (n = 64) completing the Self-Administered Full Scale IQ Test (SA-FSIQT), both made available online by Open-Source Psychometrics Project. Additionally, all participants were administered the Verbal Comprehension Index (VCI) of WASI-II by a trained researcher, with a subsection administered the full WASI-II including the Perceptual Reasoning Index (PRI) (n = 72). Both online tests demonstrated convergent validity with the WASI-II. While the online tests may only deliver a crude indicator of verbal intelligence, they provide researchers the opportunity for statistical control or screening of participants across large samples in an efficient manner not possible when using researcher-administered testing methods.


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