Search results for "Statistic"
showing 10 items of 12520 documents
A multi-purpose, multi-rotor drone system for long-range and high-altitude volcanic gas plume measurements
2021
A multi-rotor drone has been adapted for studies of volcanic gas plumes. This adaptation includes improved capacity for high-altitude and long-range, real-time SO2 concentration monitoring, long-range manual control, remotely activated bag sampling and plume speed measurement capability. The drone is capable of acting as a stable platform for various instrument configurations, including multi-component gas analysis system (MultiGAS) instruments for in situ measurements of SO2, H2S, and CO2 concentrations in the gas plume and portable differential optical absorption spectrometer (MobileDOAS) instruments for spectroscopic measurement of total SO2 emission rate, remotely controlled gas samplin…
Elementary school teachers adapt their instructional support according to students' academic skills – A variable and person-oriented approach
2015
This study examined the longitudinal associations between children’s academic skills and the instructional support teachers gave individual students. A total of 253 Finnish children were tested on reading and math skills twice in the first grade and once in the second grade. The teachers of these children rated the instructional support that they gave each child in reading and mathematics. The results showed that the poorer the student’s reading and math skills were, the more support and attention the student received from his or her teacher later on. However, instructional support did not contribute positively to the subsequent development of the students’ academic skills. The person-orie…
Reliability of measurements during countermovement jump assessments: Analysis of performance across subphases
2020
The aim of this study was to examine the reliability of performance measures in the different phases and sub-phases of the countermovement jump (CMJ). Seventeen male athletes competing at a regional level completed 204 valid trails consisting of the execution of maximal hands-on-waist CMJs performed on a force platform. The vertical ground reaction force (VGRF) data obtained at a sampling frequency of 1000 Hz were used to calculate performance-derived variables and determine key points and jump sub-phases. The relative reliability of 92 variables was assessed using the intraclass correlation coefficient (ICC) from a two-way mixed effects model analyzing the time, force, power, velocity, and…
Memory‐type control charts for censored reliability data
2023
Control charts are commonly used to monitor a process to detect undesirable changes. The main goal of this work is to propose exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) control charts to track a process by utilizing type-I censored generalized exponential (GE) distributed data. In particular, the censored data are replaced with the conditional expected value (CEV). A comparison between CUSUM and CUSUM ignoring unobserved covariates (CUSUM-IUC) charts is also a part of this study. The GE distribution is considered due to its application in reliability analysis. The performance of the charts is evaluated by using the average run length along with the standard devi…
Recognition of briefly presented familiar and unfamiliar faces
2009
Early processing stages in the perception of familiar and unfamiliar faces were studied in four experiments by varying the type of available facial information in a four alternative forced choice recognition task. Both reaction time and recognition accuracy served as dependent measures. The observed data revealed an asymmetry in processing familiar and unfamiliar faces. A markedly weak inversion effect and strong blurring effect suggest a limited usage of spatial relations within early processing stages of unfamiliar faces. Recognition performance for whole familiar faces did not deteriorate due to blurring or the presentation of isolated internal features, suggesting a low level of represe…
Longitudinal associations between adolescent behaviour problems and perceived family relationships
2010
AbstractThe goal of the present study was to examine the longitudinal associations between perceived family relationships and adolescents’ externalizing/ internalizing problems. The study sample included 366 pupils from secondary schools in Latvia, 12-14 years of age, who completed self-report questionnaires. Data were collected in two assessments 1 year apart. The results indicate that elevations in adolescent problem behavior prospectively predicted subsequent decreases in perceived family cohesion and increases in family conflict. The effect of perceived family cohesion and conflict as assessed at Time1 was not statistically significant in prediction of Time2 adolescent behaviour problem…
Emulating the Effects of Radiation-Induced Soft-Errors for the Reliability Assessment of Neural Networks
2021
International audience; Convolutional Neural Networks (CNNs) are currently one of the most widely used predictive models in machine learning. Recent studies have demonstrated that hardware faults induced by radiation fields, including cosmic rays, may significantly impact the CNN inference leading to wrong predictions. Therefore, ensuring the reliability of CNNs is crucial, especially for safety-critical systems. In the literature, several works propose reliability assessments of CNNs mainly based on statistically injected faults. This work presents a software emulator capable of injecting real faults retrieved from radiation tests. Specifically, from the device characterisation of a DRAM m…
Reliability Analysis of Three Homogeneous Fault-tolerant Inverter Topologies
2016
Abstract—In this article, non-redundant fault-tolerant inverter topologies are addressed. A novel fault-tolerant control strategy which enhances performances during post-fault operation is proposed. Benefits from the proposed strategy over conventional fault-tolerant topologies are investigated in terms of system reliability. Cost, post-fault performances, and system reliability of the proposed solution are compared with both a conventional triac-based fault-tolerant inverter and a T-type inverter. The reliability analysis of each selected configuration is carried out by means of Markov chains. The analysis is validated through a comparison of reliability and sensitivity curves. As shown by…
Hopes and Fears for the Future Among Chinese Adolescents
2014
This study examined the contents of adolescents' hopes and fears for the future in a sample of 1,975 urban and rural 8th, 10th, and 12th graders in China. Chinese adolescents' hopes and fears were most often related to future education, occupation, parental well-being, marriage and family, academics, leisure activities, wealth, interpersonal relationships, collective issues, and self-related issues. Urban adolescents compared to rural ones reported more hopes for education and leisure activities and held fewer hopes and fears for parental well-being and interpersonal relationships. Males reported more hopes and fears for marriage, whereas females reported more hopes and fears for parental w…
Machine learning for mortality analysis in patients with COVID-19
2020
This paper analyzes a sample of patients hospitalized with COVID-19 in the region of Madrid (Spain). Survival analysis, logistic regression, and machine learning techniques (both supervised and unsupervised) are applied to carry out the analysis where the endpoint variable is the reason for hospital discharge (home or deceased). The different methods applied show the importance of variables such as age, O2 saturation at Emergency Rooms (ER), and whether the patient comes from a nursing home. In addition, biclustering is used to globally analyze the patient-drug dataset, extracting segments of patients. We highlight the validity of the classifiers developed to predict the mortality, reaching…