control limits


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control limits

[kən′trōl ‚lim·əts]
(electronics)
In radar evaluation, upper and lower control limits are established at those performance figures within which it is expected that 95% of quality-control samples will fall when the radar is performing normally.
(industrial engineering)
In statistical quality control, the limits of acceptability placed on control charts; parts outside the limits are defective.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
One is the threshold at which a defect is created, the other is a limit that is established to prevent losing process control--thus the term "control limits."
The upper control limit is three sigmas above the mean and the lower control limit is three sigmas below the mean.
In order to develop this new methodology, the following issues will be discussed in the paper: (1) Determining the underlying probability distribution of a feature using the goodness-of-fit test, based on which the basic control charts are designed; (2) Determining control limits, which balances the type I and type II errors; (3) Optimal feature subset selection by minimizing a weighted summation of the type I and type II errors associated with the features considered; two selection strategies are proposed; (4) Adaptive modeling of the feature distribution using Bayesian inferences; (5) Online process monitoring with adaptive control limits and sensitizing rules.
For this purpose, the failure control limit q to determine the failure time and the fault trend control limit [l.sub.1] for early detection of slowly varying fault should first be determined.
In the case of a green sand system, engineers are not necessarily looking for outliers (individual test results falling outside the control limits), but rather looking at the overall chart line to see if the system is trending upward or downward toward one of the control limits (Fig.
The fluctuation of stock in the supermarket between the upper and lower control limits can then be assessed.
His graphs show continuous temperature plots generally tracking within the control limits and excursions (out of "control") which may indicate events--a change of energy (sunspot activity etc.
By repeating tests of the SRM bullets and cartridge cases at local and state IBIS sites, and correlating the images with the Golden Images established at the ATF, control charts and control limits were developed for quality assurance of ballistics acquisitions and correlations in NIBIN.
It follows that if a process is given and its auto covariance can be found then, at least theoretically, [2.sigma over bar.x] , E(s) and Std(s) can be found and, therefore, the control limits on [bar.x] and s can also be computed.
In the following, for determining the control limits, two approaches are explained, namely, probabilistic approach and membership approach.
Repeat strategy Description Rule 1 If all initial QC results are within mean [+ or -] 2s control limits, then accept.