An Adaptive Statistically Based Controller for Through-Feed Centerless Grinding

2000 ◽  
Vol 123 (3) ◽  
pp. 380-386 ◽  
Author(s):  
Richard W. Cowan ◽  
Daniel J. Schertz ◽  
Thomas R. Kurfess
Keyword(s):  
Standard Deviation ◽  
Statistical Approach ◽  
High Volume ◽  
Manufacturing Processes ◽  
Control Methods ◽  
Statistical Control ◽  
Accuracy And Precision ◽  
Self Tuning ◽  
Centerless Grinding ◽  
The Mean

The purpose of this research is to develop a statistically based controller that is “self-tuning.” High volume manufacturing processes such as through-feed centerless grinding are best controlled with a statistical approach, but traditional methods of statistical control generally rely on fixed parameters that must be determined. These values must be precisely known and the true physical characteristics they model must remain constant throughout grinding, or traditional statistical control methods may break down. The mean and standard deviation of a process are measures of its accuracy and precision. The scheme developed here makes control decisions based on the real-time values of these quantities. This self-adjusting ability can compensate for changes in machine parameters as they occur.

scholarly journals A Novel Methodology for Fault Identification of Multi-stage Manufacturing Process Using Product Quality Measurement

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Xiaorui Tong ◽  
Hossein D. Ardakani ◽  
David Siegel ◽  
Ellen Gamel ◽  
Jay Lee
Keyword(s):  
Product Quality ◽  
Manufacturing Process ◽  
Statistical Approach ◽  
High Volume ◽  
Fault Identification ◽  
Manufacturing Processes ◽  
Data Sets ◽  
Basic Product ◽  
Multi Stage ◽  
Quality Measurements

Data-driven modeling and fault detection of multi-stage manufacturing processes remain challenging due to the increasing complexity of the manufacturing process, the lack of structural data, data multi-dimensionality, and the additional difficulty when dealing with large data sets. The implementation of add-on sensors and establishing data acquisition, transfer, storage and analysis has the potential to facilitate advanced data modeling techniques. However, besides the associated costs, dealing with high-volume multi-dimensional data sets can be a major challenge. This paper presents a novel methodology for early fault identification of multi-stage manufacturing processes using a statistical approach. The major advantage of the proposed methodology is its reliance on only the product quality measurements and basic product manufacturing records, given the presence of peer sets. This leads to a feasible faultidentification solution in a sensor-less environment without investing costly data collection systems. The developed methodology transforms the end-of-process quality measurements to a process performance metric based on a density-based statistical approach and a peer-to-peer comparison of the machines at one stage of the process. This approach allows one to be more proactive and identify the problematic machines that could be affecting product quality. A case study in an actual multi-stage manufacturing process is used to demonstrate the effectiveness of the developed methodology.

Development of Guidelines for Accurate Measurement of Small Volume Parenteral Products Using Syringes

2019 ◽  
pp. 001857871987386
Author(s):  
Melanie A. Jordan ◽  
Dimpa Choksi ◽  
Kelsey Lombard ◽  
Lynn R. Patton
Keyword(s):  
Standard Deviation ◽  
Small Volume ◽  
Selection Methods ◽  
Accuracy And Precision ◽  
Relative Standard ◽  
Volume Measurements ◽  
The Mean ◽  
Precision And Accuracy ◽  
Parenteral Products ◽  
Sterile Product

Background: Syringes are commonly used in pharmacy compounding for the measurement of small volumes, especially in the preparation of sterile products for injection and infusion. However, there are no current official guidelines for the proper use of syringes in measuring small volumes. Objective: The purpose of this project was to determine the accuracy and precision of commercially available syringes in measuring small volumes during sterile product preparation to make recommendations for syringe size selection. Methods: To assess precision and accuracy of syringes, 3 separate investigators measured 5%, 10%, or 20% (n = 30 each) of the volume of a 1-, 3-, 5-, 10-, or 20-mL syringe with an attached 18G, 1½” needle by drawing sterile water for injection from a vial. Delivered volumes were measured gravimetrically using an electronic balance and converted to volume using the specific gravity of water (1.0). Accuracy is represented as the mean and standard deviation, while precision is represented as percent relative standard deviation. Differences were assessed using a 1-way analysis of variance with Bonferroni adjustments and significance set at P < .05. Results: Precision and accuracy were highly variable and often significantly ( P < .05) different compared to the theoretical volume delivered both within and between investigators. An increased likelihood of unacceptable error (>5%) was observed when less than 20% of the labeled capacity of a syringe was measured. Mean percent error ranged from 1.4% to 18.6%, despite manufacturer specification of ±5% accuracy, suggesting proper technique as a major factor in small-volume measurements. Conclusion: In addition to proper, validated training of syringe users, we recommend that users measure no less than 20% of the indicated volume of the syringe while choosing syringes as close as possible to the desired measurement. When possible, very small volumes should be diluted to meet the minimum volume of the smallest syringe available. Implementation of these recommendations will improve accurate dosing and, ultimately, patient safety.

scholarly journals SPC of multiple stream processes: a chart for enhanced detection of shifts in one stream

Production ◽  
2011 ◽  
Vol 21 (2) ◽  
pp. 242-253 ◽  
Author(s):  
Eugenio Kahn Epprecht ◽  
Laura França Marques Barbosa ◽  
Bruno Francisco Teixeira Simões
Keyword(s):  
Standard Deviation ◽  
Quality Characteristic ◽  
Statistical Control ◽  
Classical Scheme ◽  
The Mean ◽  
Run Lengths

The efficiency of Boyd's group charts -the classical scheme for the statistical control of multiple-stream processes- is impaired by its underlying model of the process not considering that part of the variation in such processes is common to all streams. Mortell and Runger (1995) and Runger, Alt and Montgomery (1996) proposed alternative schemes which take this fact into account. We propose a third scheme: a modified group chart, based on the differences between the values of the quality characteristic in each particular stream and the average of the values of all streams. The average run lengths of this scheme and of the competing schemes in the case of shifts in the mean of one individual stream are obtained either analytically or by simulation and compared. The results show the superiority of the proposed scheme except for shifts smaller than one standard deviation, against which no one of the schemes is really efficient.

A Reusable Unit Process Life Cycle Inventory Model for Infeed Centerless Grinding

2021 ◽  
Author(s):  
Marija Glišić ◽  
Badrinath Veluri ◽  
Devarajan Ramanujan
Keyword(s):  
Life Cycle ◽  
Life Cycle Inventory ◽  
High Volume ◽  
Inventory Model ◽  
Manufacturing Processes ◽  
Technical Documentation ◽  
Unit Process ◽  
High Volume Production ◽  
Centerless Grinding ◽  
Grinding Machine

Abstract Environmental impact minimization is an important aspect for improving the sustainability performance of manufacturing processes. Quantifying the environmental impacts of unit manufacturing processes requires systematic modeling of process life cycle inventories. This paper develops an inventory model for infeed centerless grinding based on the unit process life cycle inventory methodology. The developed model estimates the energy consumption, material losses, and consumable fluids, for a typical high-volume production setup. Process consumption data is estimated from parameters directly used for process setup as well as machine and tool specifications that can be easily obtained from technical documentation and product geometrical specification. The developed model is demonstrated using a case study involving the infeed centerless grinding of an Inconel 718 shaft on a Cincinnati Twin-Grip Centerless Grinding Machine.

At Least One Standard Deviation Above the Mean

1969 ◽  
Vol 14 (9) ◽  
pp. 470-471
Author(s):  
M. DAVID MERRILL
Keyword(s):  
Standard Deviation ◽  
The Mean

The Estimation of Blood Platelet Survival

1972 ◽  
Vol 28 (03) ◽  
pp. 447-456 ◽  
Author(s):  
E. A Murphy ◽  
M. E Francis ◽  
J. F Mustard
Keyword(s):  
Standard Deviation ◽  
Least Squares ◽  
Experimental Error ◽  
Blood Platelet ◽  
Least Squares Estimation ◽  
Systematic Relationship ◽  
Platelet Survival ◽  
The Mean ◽  
Normally Distributed

SummaryThe characteristics of experimental error in measurement of platelet radioactivity have been explored by blind replicate determinations on specimens taken on several days on each of three Walker hounds.Analysis suggests that it is not unreasonable to suppose that error for each sample is normally distributed ; and while there is evidence that the variance is heterogeneous, no systematic relationship has been discovered between the mean and the standard deviation of the determinations on individual samples. Thus, since it would be impracticable for investigators to do replicate determinations as a routine, no improvement over simple unweighted least squares estimation on untransformed data suggests itself.

PENGARUH PENDIDIKAN KESEHATAN REPRODUKSI PADA PEER GROUP (TEMAN SEBAYA) TERHADAP PENGETAHUAN DAN PERSEPSI REMAJA TENTANG PENDEWASAAN USIA PERKAWINAN DI SMA NEGERI 1 KECAMATAN NAMORAMBE KAB. DELI SERDANG 2018

2020 ◽  
Vol 1 (2) ◽  
pp. 56-66
Author(s):  
Irma Linda
Keyword(s):  
Standard Deviation ◽  
Health Education ◽  
Reproductive Health ◽  
Peer Group ◽  
Peer Groups ◽  
A Value ◽  
Significant Difference ◽  
Reproductive Health Education ◽  
The Mean ◽  
Adolescent Perceptions

Background: Early marriages are at high risk of marital failure, poor family quality, young pregnancies at risk of maternal death, and the risk of being mentally ill to foster marriage and be responsible parents. Objective: To determine the effect of reproductive health education on peer groups (peers) on the knowledge and perceptions of adolescents about marriage age maturity. Method: This research uses the Quasi experimental method with One group pre and post test design, conducted from May to September 2018. The statistical analysis used in this study is a paired T test with a confidence level of 95% (α = 0, 05). Results: There is an average difference in the mean value of adolescent knowledge between the first and second measurements is 0.50 with a standard deviation of 1.922. The mean difference in mean scores of adolescent perceptions between the first and second measurements was 4.42 with a standard deviation of 9.611. Conclusion: There is a significant difference between adolescent knowledge on the pretest and posttest measurements with a value of P = 0.002, and there is a significant difference between adolescent perceptions on the pretest and posttest measurements with a value of p = 0.001. Increasing the number of facilities and facilities related to reproductive health education by peer groups (peers) in adolescents is carried out on an ongoing basis at school, in collaboration with local health workers as prevention of risky pregnancy.

Understanding the CoVID-19 pandemic Curve through statistical approach (Preprint)

2020 ◽  
Author(s):  
Ibrar Ul Hassan Akhtar
Keyword(s):  
Probability Density ◽  
Change Point ◽  
Statistical Approach ◽  
Sudden Change ◽  
Global Scale ◽  
Change Point Detection ◽  
Segment Length ◽  
Infected Population ◽  
The Mean ◽  
Point Detection

UNSTRUCTURED Current research is an attempt to understand the CoVID-19 pandemic curve through statistical approach of probability density function with associated skewness and kurtosis measures, change point detection and polynomial fitting to estimate infected population along with 30 days projection. The pandemic curve has been explored for above average affected countries, six regions and global scale during 64 days of 22nd January to 24th March, 2020. The global cases infection as well as recovery rate curves remained in the ranged of 0 ‒ 9.89 and 0 ‒ 8.89%, respectively. The confirmed cases probability density curve is high positive skewed and leptokurtic with mean global infected daily population of 6620. The recovered cases showed bimodal positive skewed curve of leptokurtic type with daily recovery of 1708. The change point detection helped to understand the CoVID-19 curve in term of sudden change in term of mean or mean with variance. This pointed out disease curve is consist of three phases and last segment that varies in term of day lengths. The mean with variance based change detection is better in differentiating phases and associated segment length as compared to mean. Global infected population might rise in the range of 0.750 to 4.680 million by 24th April 2020, depending upon the pandemic curve progress beyond 24th March, 2020. Expected most affected countries will be USA, Italy, China, Spain, Germany, France, Switzerland, Iran and UK with at least infected population of over 0.100 million. Infected population polynomial projection errors remained in the range of -78.8 to 49.0%.

Regularity and latency of units in ventral cochlear nucleus: implications for unit classification and generation of response properties

1988 ◽  
Vol 60 (1) ◽  
pp. 1-29 ◽  
Author(s):  
E. D. Young ◽  
J. M. Robert ◽  
W. P. Shofner
Keyword(s):  
Standard Deviation ◽  
Cochlear Nucleus ◽  
Interspike Interval ◽  
Rate Adaptation ◽  
Stellate Cells ◽  
Instantaneous Rate ◽  
Ventral Cochlear Nucleus ◽  
Bushy Cell ◽  
Low Pass ◽  
The Mean

1. The responses of neurons in the ventral cochlear nucleus (VCN) of decerebrate cats are described with regard to their regularity of discharge and latency. Regularity is measured by estimating the mean and standard deviation of interspike intervals as a function of time during responses to short tone bursts (25 ms). This method extends the usual interspike-interval analysis based on interval histograms by allowing the study of temporal changes in regularity during transient responses. The coefficient of variation (CV), equal to the ratio of standard deviation to mean interspike interval, is used as a measure of irregularity. Latency is measured as the mean and standard deviation of the latency of the first spike in response to short tone bursts, with 1.6-ms rise times. 2. The regularity and latency properties of the usual PST histogram response types are shown. Five major PST response type classes are used: chopper, primary-like, onset, onset-C, and unusual. The presence of a prepotential in a unit's action potentials is also noted; a prepotential implies that the unit is recorded from a bushy cell. 3. Units with chopper PST histograms give the most regular discharge. Three varieties of choppers are found. Chop-S units (regular choppers) have CVs less than 0.35 that are approximately constant during the response; chop-S units show no adaptation of instantaneous rate, as measured by the inverse of the mean interspike interval. Chop-T units have CVs greater than 0.35, show an increase in irregularity during the response and show substantial rate adaptation. Chop-U units have CVs greater than 0.35, show a decrease in irregularity during the response, and show a variety of rate adaptation behaviors, including negative adaptation (an increase in rate during a short-tone response). Irregular choppers (chop-T and chop-U units) rarely have CVs greater than 0.5. Choppers have the longest latencies of VCN units; all three groups have mean latencies at least 1 ms longer than the shortest auditory nerve (AN) fiber mean latencies. 4. Chopper units are recorded from stellate cells in VCN (35, 42). Our results for chopper units suggest a model for stellate cells in which a regularly firing action potential generator is driven by the summation of the AN inputs to the cell, where the summation is low-pass filtered by the membrane capacitance of the cell.(ABSTRACT TRUNCATED AT 400 WORDS)

Sign in / Sign up

Export Citation Format

Share Document