Search results for " Reliability"
showing 10 items of 557 documents
Economic Robustness Analysis of Adaptive Chart Schemes for Monitoring the Total Nonconformities Number in Inspection Units
2015
In recent years, a variety of enhanced schemes for the c chart have been developed aimed at the effectiveness improving of the related statistical process control (SPC) procedures. However, the performance of such chart schemes can be very sensitive to values assumed for some operating and cost parameters, in particular to the considered process shift magnitude arising from out-of-control conditions. In such a circumstance, the effectiveness of such chart schemes can be subjected to substantial reductions when they are implemented in operative contexts given that, in practice, such value is unknown and it can be very difficult to accurately estimate. For this reason, in the present paper i…
A Multi-Objective Design Approach for the c Chart Considering Taguchi Loss Function
2013
The present paper proposes a multi-objective design approach for the c chart, considering in the optimization process of the chart parameters both the statistical and the economic objectives. In particular, the minimization of the hourly total quality related costs is the considered objective to carry out the economic goal, whereas the statistical objective is reached by the minimization the out-of-control average run length of the chart. A mixed integer non-linear constrained mathematical model is formulated to solve the treated multi-objective optimization problem, whereas the Pareto optimal frontier is described by the e-constraint method. In order to show the employment of the proposed …
Comparing the Economic Effectiveness of Various Adaptive Schemes for the c Chart
2013
In an attempt to improve the effectiveness of statistical process control (SPC) procedures, a variety of adaptive schemes has been developed in the last decades. However, considering control charts for attributes, relatively few works about adaptive schemes have been proposed, and most of them were proposed only recently. The common characteristic of those schemes is that one or more chart parameters are allowed to adaptively vary during the SPC operations according to the sampling information history, typically the current point plotted on the chart. In this way, the adaptive schemes are smarter than the related static ones, but they are also more complicated in terms of implementation. Th…
An Effective Double Sampling Scheme for thecControl Chart
2013
In the present paper is developed a statistical process control inspection procedure based on a new simple-to-implement and effective double sampling scheme for the c control chart, aimed at the minimization of the number of inspected observation units and warranting fixed levels for the type I and II error risks. In particular, the formulations of the false alarm risk α, the power P of the chart, and the expected number of inspected observation units for the developed inspection procedure are given, whereas a macro of Microsoft Excel is adopted to solve the tackled problem. In order to illustrate the application of the developed approach and to investigate on the influence of several opera…
Economic Design Approach for an SPC Inspection Procedure Implementing The Adaptive C Chart
2013
The present paper proposes a design approach for a statistical process control (SPC) procedure implementing a c control chart for non-conformities, with the aim to minimize the hourly total quality-related costs. The latter take into account the costs arising from the non-conforming products while the process is in-control and out-of-control, for false alarms, for assignable cause locations and system repairs, for sampling and inspection activities and for the system downtime. The proposed economic optimization approach is constrained by the expected hourly false alarms frequency, as well as the available labor resource level. A mixed integer non-linear constrained mathematical model is dev…
The new version of the pictorial scale of Perceived Movement Skill Competence in Spanish children: Evidence of validity and reliability. [La nueva ve…
2019
The purpose of this study was to i) examine reliability and construct validity of the pictorial scale of Perceived Movement Skill Competence (PMSC) aligned to the third version of the Test of Gross Motor Development (TGMD-3) in a sample of Spanish children; and to ii) analyse the validity of the PMSC and children’s perceived motor competence (MC) according to gender. A convenience sample of 361 children (55.7% boys) between 4 and 11 years-old participated. The pictorial scale of PMSC (19 items) was administered (a random subsample repeated the PMSC twice). Test-retest reliability using Intraclass Correlation Coefficients and construct validity using a Bayesian Structural Equation Modeling a…
Questions and controversies in the study of time-varying functional connectivity in resting fMRI.
2020
The brain is a complex, multiscale dynamical system composed of many interacting regions. Knowledge of the spatiotemporal organization of these interactions is critical for establishing a solid understanding of the brain’s functional architecture and the relationship between neural dynamics and cognition in health and disease. The possibility of studying these dynamics through careful analysis of neuroimaging data has catalyzed substantial interest in methods that estimate time-resolved fluctuations in functional connectivity (often referred to as “dynamic” or time-varying functional connectivity; TVFC). At the same time, debates have emerged regarding the application of TVFC analyses to re…
Metodologies competencials en la formació literària de mestres: experiències didàctiques per fomentar el pensament reflexiu: Competence-based methodo…
2023
L’objectiu d’aquest article és descriure i analitzar alguns projectes d’educació literària realitzats durant els últims vuit anys en el marc de la formació de docents per tal de reflexionar sobre la importància de l’ús de metodologies actives i competencials per l’ensenyament de la literatura al context universitari. Aquests projectes conformen experiències didàctiques com ara tallers d’escriptura, rutes literàries i l’ús dels videojocs per al foment lector. Presentem un comentari qualitatiu dels resultats d’aprenentatge més significatius i de la valoració dels estudiants a partir de la tria de diverses mostres. Finalment, arribem a la conclusió que aquestes experiències promouen no només l…
The link between violence and suicidal behavior among female university students in Spain
2019
Objective: To explore the association between violence and suicidal behavior in female university students. Method: A convenience sample of 540 female students enrolled in the Nursing and Teacher Training Faculties at the University of Valencia was selected. Violence by partners, nonpartners, and both was compared with suicidal thoughts and suicide attempts. An adjusted logistic regression and the Wald Test were performed to explore whether the effect on student's suicidal behavior differed if a partner or others committed violence. Results: 18.1% reported suicidal thoughts in the last month and 2.4% had attempted suicide in the past five years. Suicidal behavior was significantly higher in…
Physical Education Teachers’ Perceived Sexual and Physical Violence and Work-related Stress
2020
This study investigated the relationships between sexual (verbal and non-verbal sexual harassment) and physical violence against physical education (PE) teachers and work-related stress. Participants were 175 (females 122, males 53) Finnish PE teachers aged between 27 and 62 years. The findings showed that 1) higher perceived physical violence was positively associated with higher perceived non-verbal sexual harassment and work-related stress; 2) teachers with a sport science degree perceived higher work-related stress mediated by physical violence than other teachers; 3) longer-serving PE teachers reported lower verbal sexual harassment than teachers with less teaching experience; and 4) f…