reliability measures
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2022 ◽  
Author(s):  
Martin Girard ◽  
Marie-Hélène Roy Cardinal ◽  
Michaël Chassé ◽  
Sébastien Garneau ◽  
Yiorgos Alexandros Cavayas ◽  
...  

Background Mechanical ventilation is a common therapy in operating rooms and intensive care units. When ill-adapted, it can lead to ventilator-induced lung injury (VILI), which is associated with poor outcomes. Excessive regional pulmonary strain is thought to be a major mechanism responsible for VILI. Scarce bedside methods exist to measure regional pulmonary strain. We propose a novel way to measure regional pleural strain using ultrasound elastography. Research Question The objective of this study was to assess the feasibility and reliability of pleural strain measurement by ultrasound elastography and to determine if elastography parameters would correlate with varying tidal volumes. Study Design and Methods A single-blind randomized crossover proof of concept study was conducted July to October 2017 at a tertiary care referral center. Ten patients requiring general anesthesia for elective surgery were recruited. After induction, patients were received tidal volumes of 6, 8, 10 and 12 mL.kg-1 in random order, while pleural ultrasound cineloops were acquired at 4 standardized locations. Ultrasound radiofrequency speckle tracking allowed computing various pleural translation, strain and shear components. These were screened to identify those with the best dose-response with tidal volumes using linear mixed effect models. Goodness-of-fit was assessed by the coefficient of determination. Intraobserver, interobserver and test-retest reliability were calculated using intraclass correlation coefficients. Results Analysis was possible in 90.7% of ultrasound cineloops. Lateral absolute shear, lateral absolute strain and Von Mises strain varied significantly with tidal volume and offered the best dose-responses and data modelling fits. Point estimates for intraobserver reliability measures were excellent for all 3 parameters (0.94, 0.94 and 0.93, respectively). Point estimates for interobserver (0.84, 0.83 and 0.77, respectively) and test-retest (0.85, 0.82 and 0.76, respectively) reliability measures were good. Interpretation Strain imaging is feasible and reproducible, and may eventually guide mechanical ventilation strategies in larger cohorts of patients.


Author(s):  
Zafar Iqbal ◽  
Muhammad Rashad ◽  
Iram Rauf ◽  
Muhammad Salman

A new BEME distribution known as beta Exponentiated moment exponential (BEME) distribution is proposed. We provide here some shape properties, moments in the form of special functions, mean deviations of BEME distribution. We derive mathematical properties of the BEME distribution including the reliability measures, the Bonferroni and the Lorenz curves, rth order statistics, measures of uncertainty: the Shannon entropy measure and the s-entropy measure. The parameters of the BEME distribution are estimated by the method of maximum likelihood estimation and estimated non-linear equations for these estimates are presented. The application of BEME distribution is explored in three different fields of engineering.


2021 ◽  
Author(s):  
Joseph Rios ◽  
Jiayi Deng

An underlying threat to the validity of reliability measures is the introduction of systematic variance in examinee scores from unintended constructs that differ from those assessed. One construct-irrelevant behavior that has gained increased attention in the literature is rapid guessing (RG), which occurs when examinees answer quickly with intentional disregard for item content. To examine the degree of distortion in coefficient alpha due to RG, this study compared alpha estimates between conditions in which simulees engaged in full solution (i.e., do not engage in RG) versus partial RG behavior. This was done by conducting a simulation study in which the percentage and ability characteristics of rapid responders as well as the percentage and pattern of RG were manipulated. After controlling for test length and difficulty, the average degree of distortion in estimates of coefficient alpha due to RG ranged from -.04 to .02 across 144 conditions. Although slight differences were noted between conditions differing in RG pattern and RG responder ability, the findings from this study suggest that estimates of coefficient alpha are largely robust to the presence of RG due to cognitive fatigue and a low perceived probability of success.


2021 ◽  
pp. 014662162110517
Author(s):  
Joseph A. Rios ◽  
Jiayi Deng

An underlying threat to the validity of reliability measures is the introduction of systematic variance in examinee scores from unintended constructs that differ from those assessed. One construct-irrelevant behavior that has gained increased attention in the literature is rapid guessing (RG), which occurs when examinees answer quickly with intentional disregard for item content. To examine the degree of distortion in coefficient alpha due to RG, this study compared alpha estimates between conditions in which simulees engaged in full solution (i.e., do not engage in RG) versus partial RG behavior. This was done by conducting a simulation study in which the percentage and ability characteristics of rapid responders as well as the percentage and pattern of RG were manipulated. After controlling for test length and difficulty, the average degree of distortion in estimates of coefficient alpha due to RG ranged from −.04 to .02 across 144 conditions. Although slight differences were noted between conditions differing in RG pattern and RG responder ability, the findings from this study suggest that estimates of coefficient alpha are largely robust to the presence of RG due to cognitive fatigue and a low perceived probability of success.


Author(s):  
Nafeesa Bashir ◽  
JPS Joorel ◽  
T R Jan

Planning a highly reliable and efficient system has always been a primary interest for reliability engineers by devising the powerful design strategy and employing effective repair and replacement policy. Keeping in view this, the basic aim of this paper is to analyze the reliability of a system which comprised of two units A and B in which unit A is functional and B is held standby. Unit A after failure may be controlled or uncontrolled. The failed unit undergoes for repair in the controlled unit. If the repair of a unit is not controlled then it is replaced by a new one.  Upon the breakdown of operational unit A, unit B come becomes active instantaneously. Unit B after failure is repaired by regular repairmen. System failure takes place when both the units quit serving. The unit serves as good as a fresh after preventive repair and replacement policy. The regenerative point technique has been used to obtain the expression for several reliability measures. Finally, the graphical behavior of MTSF and profit of the present model has been observed for arbitrary values of parameters and costs.


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