The curriculum of technical bachelor programs often focuses on various theories in order to emphase understanding but there is also an actual need to provide the students with specific technical ...skills. This paper presents an effective means to evaluate the students’ capability to measure geometrical product specifications namely the procedure of Repeatability and Reproducibility by variables. The measurement results were processed using MINITAB statistical software with its module called Gage R&R Study. The conclusion was that the analyzed measurement system is excellent.
Using optical coherence tomography angiography (OCTA), this study compared intrasession repeatability versus intersession reproducibility of macular vessel parameters in glaucoma and non-glaucoma ...subjects.
6 × 6 mm
2
macular OCTA scans (Cirrus HD-OCT 5000) were acquired from glaucomatous and non-glaucomatous subjects as part of an observational, longitudinal study. Vessel area density (VAD) and vessel skeleton density (VSD) were calculated using research-based quantification software while perfusion density (PD
Z
) and vessel density (VD
Z
) were calculated using commercially developed software (Cirrus 11.0, Carl Zeiss Meditec). Intrasession repeatability and intersession reproducibility were determined using within-eye standard deviation (S
W
), within-eye coefficient of repeatability (CR
W
), within-eye coefficient of variation (CV
W
), and intraclass correlation coefficients (ICC).
The intrasession repeatability and intersession reproducibility for macular OCTA parameters were similar to one another for both non-glaucomatous and glaucomatous eyes. Intrasession CV
W
from the non-glaucoma group (n = 73) was 1.097% for VAD, 1.007% for VSD, 2.980% for PD
Z
, and 2.714% for VDZ. Intersession CV
W
from the non-glaucoma group (n = 55) was 1.389% for VAD, 1.279% for VSD, 2.935% for PD
Z
, and 2.695% for VD
Z
. Intrasession CV
W
from the glaucoma group (n = 59) was 1.189% for VAD, 0.970% for VSD, 3.827% for PD
Z
, and 3.542% for VD
Z
. Intersession CV
W
from the glaucoma group (n = 45) was 1.412% for VAD, 1.132% for VSD, 3.915% for PD
Z
, and 3.654% for VD
Z
. Non-glaucomatous intrasession ICC ranged from 0.711 to 0.824, non-glaucomatous intersession ICC ranged from 0.649 to 0.762, glaucomatous intrasession ICC ranged from 0.710 to 0.853, and glaucomatous intersession ICC ranged from 0.661 to 0.827.
Macular OCTA scans can be a useful tool in monitoring the longitudinal progression of glaucoma due to their high repeatability and reproducibility.
In general, the labeling process provides a set of annotations that are used for supervised learning. A major assumption of this process is that each annotation represents the ground truth about an ...observed phenomenon, which is defined by manually labeling it. While most extant Deep Learning (DL) research is focused on improving the accuracy and efficiency of training and inferencing algorithms, only limited attention has been paid to data validation. Potential inconsistencies in the labeling process for DL are in this less investigated category. This study assessed the performance of You Only Look Once version 5 small (YOLOv5s) using confidence intervals (CIs) for each defect type in a metal defect benchmark dataset, GC10 DET. The impacts of standardizing the labeling process and the role of consistency in labeling were evaluated through an experimental study. The results showed that individually labeled small-size defects with precise bounding boxes perform better than defects labeled inconsistently in a group. Improved data validation through precise labeling increased average precision (AP) by 12.26–25.78 % across defect categories. This overall result points to the need for further evaluation of an image dataset through data validation before comparing algorithms on a benchmark dataset and using bootstrap CIs when categories have limited data.
•Repeatability and reproducibility of MR-linac DWI sequences were within 2.22% and 4.37% of MR sim DWI sequences, respectively.•Of the MR-linac DWI sequences, SPLICE generally outperformed EPI and ...TSE in terms of repeatability/reproducibility, ADC bias, and SNR.•Spatial dependence of phantom ADC values was observed for the MR-linac but not for the MR sim, which may be due to uncorrected gradient non-linearities.•MR-linac DWI sequences are robust and worthy of further clinical evaluation for treatment response assessment and biological image-guided ART in HNC.
Diffusion-weighted imaging (DWI) on MRI-linear accelerator (MR-linac) systems can potentially be used for monitoring treatment response and adaptive radiotherapy in head and neck cancers (HNC) but requires extensive validation. We performed technical validation to compare six total DWI sequences on an MR-linac and MR simulator (MR sim) in patients, volunteers, and phantoms.
Ten human papillomavirus-positive oropharyngeal cancer patients and ten healthy volunteers underwent DWI on a 1.5 T MR-linac with three DWI sequences: echo planar imaging (EPI), split acquisition of fast spin echo signals (SPLICE), and turbo spin echo (TSE). Volunteers were also imaged on a 1.5 T MR sim with three sequences: EPI, BLADE (vendor tradename), and readout segmentation of long variable echo trains (RESOLVE). Participants underwent two scan sessions per device and two repeats of each sequence per session. Repeatability and reproducibility within-subject coefficient of variation (wCV) of mean ADC were calculated for tumors and lymph nodes (patients) and parotid glands (volunteers). ADC bias, repeatability/reproducibility metrics, SNR, and geometric distortion were quantified using a phantom.
In vivo repeatability/reproducibility wCV for parotids were 5.41%/6.72%, 3.83%/8.80%, 5.66%/10.03%, 3.44%/5.70%, 5.04%/5.66%, 4.23%/7.36% for EPIMR-linac, SPLICE, TSE, EPIMR sim, BLADE, RESOLVE. Repeatability/reproducibility wCV for EPIMR-linac, SPLICE, TSE were 9.64%/10.28%, 7.84%/8.96%, 7.60%/11.68% for tumors and 7.80%/9.95%, 7.23%/8.48%, 10.82%/10.44% for nodes. All sequences except TSE had phantom ADC biases within ± 0.1x10-3 mm2/s for most vials (EPIMR-linac, SPLICE, and BLADE had 2, 3, and 1 vials out of 13 with larger biases, respectively). SNR of b = 0 images was 87.3, 180.5, 161.3, 171.0, 171.9, 130.2 for EPIMR-linac, SPLICE, TSE, EPIMR sim, BLADE, RESOLVE.
MR-linac DWI sequences demonstrated near-comparable performance to MR sim sequences and warrant further clinical validation for treatment response assessment in HNC.
Material properties are crucial input parameters for the analysis of heat, air and moisture transfer phenomena in built environment. However, many round robin tests reveal that the measurements on ...material properties – especially hygric properties – have poor reproducibility. Thus the measurement and data analysis methods should be questioned, and the currently available databases for material properties are not perfectly reliable.
In this paper we aim at analyzing the material errors, repeatability errors, between-lab errors and reproducibility errors involved in the determination of hygric properties of porous building materials. The same materials as those used in the EC HAMSTAD project – autoclaved aerated concrete, calcium silicate board and ceramic brick – are chosen as target materials in our tests to facilitate error analysis. Static gravimetric tests, cup tests, capillary absorption tests, vacuum saturation tests and pressure plate tests have been repeated three times under repeatability conditions. Then the experimental results are analyzed in combination with the EC HAMSTAD report to calculate various errors. Results show that different materials have different heterogeneity errors, which can hardly be avoided. Moreover, in general these tests have excellent repeatability, indicating that under proper control the tests themselves are trustworthy. However, the large between-lab errors and the subsequent poor reproducibility demonstrate that in different labs the experimental procedures, condition controls, as well as data processing methods can deviate significantly. As a result, stricter and more detailed instructions are needed to improve the reproducibility of the tests for determining the hygric properties of porous building materials.
•Repeatability and reproducibility tests are combined together for error analysis.•Materials' heterogeneity errors vary according to different tests and conditions.•Repeatability errors are in general negligibly small for tests on hygric properties.•Reproducibility errors are significant, calling for more detailed prescriptions.
ABSTRACT The application of leaf area index (LAI) in coffee crop management depends on the availability of methodologies for proper estimation. The objective of this study was to develop a ...methodology for the visual assessment of LAI in coffee fields and to establish a protocol for training, evaluation, and feedback for evaluators. Four rounds of LAI measurements were conducted using visual estimates, two instruments (LAI 2200-C and AccuPAR LP-80), and defoliation of coffee hedgerows in Poás, Costa Rica. In each round, five workers visually estimated the LAI values on two occasions separated by 15 days, and feedback reinforcement was provided to each worker at the end of each round. Visual assessments showed high repeatability and reproducibility and the estimates were adjusted to the linear regression model in most cases. Evaluators improved their capacity to visually assess the LAI throughout the rounds, as the value of R2increased consistently for most workers, with values as high as 0.87. Instrumentation evaluation of LAI produced R2values of 0.5-0.6, with significant underestimation bias. The performance of the different methods is discussed in the context of widely spaced hedgerows. The proposed visual methodology constitutes a statistically sound, rapid, simple, and reliable method for determining the LAI of coffee fields to aid in decision-making for crop management.
RESUMO A aplicação do índice de área foliar (IAF) na gestão da cultura do cafeeiro depende da disponibilidade de metodologias para sua estimativa correta. É proposta aqui uma metodologia para a avaliação visual do IAF em plantas de café, por tanto se estabelece um protocolo para o treinamento dos avaliadores. Foram feitas quatro rodadas de medições do IAF utilizando estimativas visuais, dois instrumentos (LAI 2200-C e AccuPAR LP-80), e desfolhações de sebes de café na Costa Rica. A cada rodada, cinco trabalhadores estimaram visualmente os valores do IAF em duas ocasiões e separados por 15 dias. Ao final de cada rodada, foi dada uma retroalimentação a cada trabalhador. A avaliação visual mostrou alta repetibilidade e reprodutibilidade, e as estimativas foram ajustadas para o modelo de regressão linear na maioria dos casos. Os avaliadores melhoraram sua capacidade de avaliar visualmente o IAF ao longo das rodadas, e o valor de R2 aumentou consistentemente para a maioria dos trabalhadores, com valores tão altos quanto 0,87. A avaliação do IAF por instrumentos produziu valores de R2 de 0,5-0,6, com significativa tendência de subestimação, e não se ajustou ao modelo de regressão linear. O desempenho dos diferentes métodos é discutido no contexto de coberturas com amplo espaço. A metodologia visual proposta constitui uma determinação sólida, rápida, simples e confiável do IAF na lavoura do café e considera-se uma ajuda na tomada de decisões para a gestão da safra.
•Flash-pulse thermographic inspection of carbon-fiber composites.•Infrared non-destructive testing of materials.•Repeatability and reproducibility of non-destructive inspection.•Gage R&R analysis ...based on contrast and size of indications.
Thermographic flash-pulse inspection is a popular technique of non-destructive testing (NDT) of carbon-fiber composites. Despite of an automation of the NDT methods, most of them are based on a visual inspection of indications and results of the inspections are thus influenced by the skills of operators. Repeatability and reproducibility (R&R) analysis of these inspections are therefore more important than in the case of exact gauge-type methods. This study was focused on statistical evaluation of flash pulse inspection. Space hardware representative carbon-fiber composite samples with 50 artificial defects were used as reference samples, which were independently inspected by three operators in two independent runs.Gauge R&R study was performed based on contrast to noise ratio and size of defects indications. It was determined, that, at certain conditions, a total Gage R&R variability 23% and 45% can be achieved for the diameter and the contrast to noise ratio evaluation, respectively.
Ultrasound (US) is an increasingly prevalent and effective diagnostic modality for neuromuscular imaging. Gray-scale B-mode imaging has been the dominant US approach to evaluating nerves ...qualitatively or making morphometric measurements of nerves, providing important insights into pathological changes for conditions such as carpal tunnel syndrome. Among more recent ultrasound strategies, high-frequency ultrasound (often defined as >15 MHz for clinical applications), quantitative ultrasound and image textural analysis offer promising enhancements for improved and more objective approaches to nerve imaging. In this study, we evaluated the repeatability and reproducibility of backscatter coefficient (BSC) and imaging texture features extracted by gray-level co-occurrence matrices (GLCMs) in homogeneous tissue-mimicking reference phantoms and in median nerves in the wrists of healthy participants. We also investigated several practical sources of variability in the assessment of quantitative parameters, including influences of operators, and participant-to-participant variability. Overall, BSC- and GLCM-based outcomes are highly repeatable and reproducible after operator training, based on measurement of descriptive statistics, repeatability coefficient (RC) and reproducibility coefficient recommended by Quantitative Imaging Biomarker Alliance (QIBA RDC). GLCM parameters appear more reproducible and repeatable than BSC-based parameters in healthy participants in vivo. However, such variability noted here must be compared with the value ranges and variability of the results in pathological nerves, including median nerves afflicted by trauma, overuse syndromes such as carpal tunnel syndrome and after surgical repair.
PDF
