scholarly journals Quality control strategies for brain MRI segmentation and parcellation: practical approaches and recommendations - insights from The Maastricht Study

2021 ◽  
Author(s):  
Jennifer Monereo Sánchez ◽  
Joost J.A. de Jong ◽  
Gerhard S. Drenthen ◽  
Magdalena Beran ◽  
Walter H. Backes ◽  
...  
Keyword(s):  
Quality Control ◽  
Control Strategies ◽  
Brain Mri ◽  
Test Case ◽  
Euler Numbers ◽  
Brain Volumes ◽  
Before And After ◽  
Unexplained Variance ◽  
Quality Control Strategy ◽  
Automated Quality Control

ABSTRACTBackgroundQuality control of brain segmentation is a fundamental step to ensure data quality. Manual quality control is the current gold standard, despite unfeasible in large neuroimaging samples. Several options for automated quality control have been proposed, providing potential time efficient and reproducible alternatives. However, those have never been compared side to side, which prevents to reach consensus in the appropriate QC strategy to use. This study aims to elucidate the changes manual editing of brain segmentations produce in morphological estimates, and to analyze and compare the effects of different quality control strategies in the reduction of the measurement error.MethodsWe used structural MR images from 259 participants of The Maastricht Study. Morphological estimates were automatically extracted using FreeSurfer 6.0. A subsample of the brain segmentations with inaccuracies was manually edited, and morphological estimates were compared before and after editing. In parallel, 11 quality control strategies were applied to the full sample. Those included: a manual strategy, manual-QC, in which images were visually inspected and manually edited; five automated strategies where outliers were excluded based on the tools MRIQC and Qoala-T, and the metrics morphological global measures, Euler numbers and Contrast-to-Noise ratio; and five semi-automated strategies, were the outliers detected through the mentioned tools and metrics were not excluded, but visually inspected and manually edited. We used a regression of morphological brain measures against age as a test case to compare the changes in relative unexplained variance that each quality control strategy produces, using the reduction of relative unexplained variance as a measure of increase in quality.ResultsManually editing brain surfaces produced changes particularly high in subcortical brain volumes and moderate in cortical surface area, thickness and hippocampal volumes. The exclusion of outliers based on Euler numbers yielded a larger reduction of relative unexplained variance for measurements of cortical area, subcortical volumes and hippocampal subfields, while manual editing of brain segmentations performed best for cortical thickness. MRIQC produced a lower, but consistent for all types of measures, reduction in relative unexplained variance. Unexpectedly, the exclusion of outliers based on global morphological measures produced an increase of relative unexplained variance, potentially removing more morphological information than noise from the sample.ConclusionOverall, the automatic exclusion of outliers based on Euler numbers or MRIQC are reliable and time efficient quality control strategies that can be applied in large neuroimaging cohorts.

scholarly journals Quality control strategies for brain MRI segmentation and parcellation: practical approaches and recommendations - insights from The Maastricht Study

NeuroImage ◽  
2021 ◽  
pp. 118174
Author(s):  
Jennifer Monereo-Sánchez ◽  
Joost J.A. de Jong ◽  
Gerhard S. Drenthen ◽  
Magdalena Beran ◽  
Walter H. Backes ◽  
...  
Keyword(s):  
Quality Control ◽  
Control Strategies ◽  
Brain Mri ◽  
Mri Segmentation

The Practical Application of Advanced Statistical Techniques for Computer-Based Quality Control

1993 ◽  
Author(s):  
David C. Robinson ◽  
Ebrahim Mazharsolook ◽  
David A. Sanders
Keyword(s):  
Quality Control ◽  
Control Strategies ◽  
Innovative Methods ◽  
On Line ◽  
Computer Based ◽  
Product And Process ◽  
Quality Control Strategy ◽  
First Time ◽  
Line Analysis

Abstract Innovative methods are explored for computer based quality control of parts manufacture. The approach is based on the use of analysis of variance techniques and regression modelling to formulate a description (model) of the product and process in terms of product quality. This model is then employed in a computer based on-line quality control strategy in which the aim is to optimise manufacturing quality by attempting to compensate for product deviations. Available quality control software is based on methodologies developed in the 1920s [1]. It is concerned with the presentation of data and off-line analysis rather than the decision making process. By integrating statistics and quality control strategies, computer based decisions can be formulated based on larger quantities of data than a human could assimilate. Such decisions can be made more accurately and in a fraction of the time taken by manual means. A case study is presented which is concerned with the implementation of computer based on-line quality control of manufacture. This case study was successfully completed with a reduction in the first time reject rate from thirty percent to below four percent. The case study shows the generic nature of the method and also the diversity of application.

Measurements method of the audio recordings acoustic quality indicator prepared for registration and processing in the Unified Biometric System

2019 ◽  
pp. 40-46 ◽  
Author(s):  
V.V. Savchenko ◽  
A.V. Savchenko
Keyword(s):  
Quality Control ◽  
Small Sample Size ◽  
Personal Data ◽  
Digital Processing ◽  
Small Sample ◽  
Practical Implementation ◽  
Acoustic Measurements ◽  
Pitch Frequency ◽  
Wide Range ◽  
Automated Quality Control

We consider the task of automated quality control of sound recordings containing voice samples of individuals. It is shown that in this task the most acute is the small sample size. In order to overcome this problem, we propose the novel method of acoustic measurements based on relative stability of the pitch frequency within a voice sample of short duration. An example of its practical implementation using aninter-periodic accumulation of a speech signal is considered. An experimental study with specially developed software provides statistical estimates of the effectiveness of the proposed method in noisy environments. It is shown that this method rejects the audio recording as unsuitable for a voice biometric identification with a probability of 0,95 or more for a signal to noise ratio below 15 dB. The obtained results are intended for use in the development of new and modifying existing systems of collecting and automated quality control of biometric personal data. The article is intended for a wide range of specialists in the field of acoustic measurements and digital processing of speech signals, as well as for practitioners who organize the work of authorized organizations in preparing for registration samples of biometric personal data.

scholarly journals Dynamic grid fault analysis in wind power plant with DFIG by using supervisory control and data acquisition (SCADA) viewer

2020 ◽  
Vol 181 ◽  
pp. 03006
Author(s):  
Nduwamungu Aphrodis ◽  
Ntagwirumugara Etienne ◽  
Utetiwabo Wellars ◽  
Mulolani Francis
Keyword(s):  
Power Systems ◽  
Power Flow ◽  
Control Strategies ◽  
Electrical Power ◽  
Fault Analysis ◽  
Operational Mode ◽  
Electrical Power Systems ◽  
Fault Ride Through ◽  
Before And After ◽  
Clearing Time

Faults in electrical power systems are among the key factors and sources to network disturbances, however control strategies are among key faults clearing techniques for the sake of safe operational mode of the system.Some researchers have shown various limitations of control strategies such as slow dynamic response,inability to switch Off and On network remotely and fault clearing time. For a system with wind energy technologies, if the power flow of a wind turbine is interrupted by a fault, the intermediate-circuit voltage between the machine-side converter and line-side converter will fall in unacceptably high values.To overcome the aforementioned issues, this paper used a Matlab simulations and experiments in order to analyze and validate the results.The results showed that fault ride through (FRT) with SCADA Viewer software are more adaptable to the variations of voltage and wind speed in order to avoid loss of synchronism. Therefore at the speed of 12.5m/s a wind produced a rated power of 750W and remained in synchronization before and after a fault created and cleared but worked as generator meanwhile at speed of 3.4m/s wind disconnected from grid and started working as a motor and consumed active power (P=-25watts) and voltage dip at 100% .For the protection purpose, the DC chopper and crowbar should be integrated towards management of excess energy during faults cases.

Cutter Interchangeability for Spiral-Bevel and Hypoid Gear Manufacturing

2003 ◽  
Author(s):  
Claude Gosselin ◽  
Jack Masseth ◽  
Wei Liang
Keyword(s):  
Test Case ◽  
Hypoid Gear ◽  
Hypoid Gears ◽  
Manufacturing Operations ◽  
Before And After ◽  
Gear Manufacturing ◽  
Spiral Bevel ◽  
Tooth Flank ◽  
Tooth Flank Surface Topography ◽  
Flank Surface

In the manufacturing of spiral-bevel and hypoid gears, circular cutter dimensions are usually based on the desired performance of a gear set. In large manufacturing operations, where several hundred gear geometries may have been cut over the years, the necessary cutter inventory may become quite large since the cutter diameters will differ from one geometry to another, which results in used storage space and associated costs in purchasing and maintaining the cutter parts. Interchangeability of cutters is therefore of significant interest to reduce cost while maintaining approved tooth geometries. An algorithm is presented which allows the use of a different cutter, either in diameter and/or pressure angle, to obtain the same tooth flank surface topography. A test case is presented to illustrate the usefulness of the method: the OB cutter diameter of an hypoid pinion is changed from 8.9500" to 9.1000". CMM results and the comparison of the bearing patterns before and after change show excellent correlation, and indicate that the new pinion can be used in place of the original pinion without performance or quality problems. Significant cost reductions may be obtained with the application of the method.

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