381 research outputs found

    Sampling-based Uncertainty Estimation for an Instance Segmentation Network

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    The examination of uncertainty in the predictions of machine learning (ML) models is receiving increasing attention. One uncertainty modeling technique used for this purpose is Monte-Carlo (MC)-Dropout, where repeated predictions are generated for a single input. Therefore, clustering is required to describe the resulting uncertainty, but only through efficient clustering is it possible to describe the uncertainty from the model attached to each object. This article uses Bayesian Gaussian Mixture (BGM) to solve this problem. In addition, we investigate different values for the dropout rate and other techniques, such as focal loss and calibration, which we integrate into the Mask-RCNN model to obtain the most accurate uncertainty approximation of each instance and showcase it graphically

    Computer Vision and Sensor Fusion for Autonomous Vehicles

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    Cars, particularly manually-driven cars, are one of the most commonly used modes of transportation today. However, millions of people are either killed or left with disabilities annually due to road traffic accidents caused by human error or sensor failures. Despite that, a lot of people seem reluctant to look into alternatives to manually driven vehicle transportation. This is understandable as driving cars has been the trustworthy mode of transportation for many years, and it is widely used in everyday life around the world. However, technological advances in the fields of machine learning and cyber-physical systems contributed to the emergence of nearly or fully autonomous vehicles, or driverless cars, as a true viable alternative for the current human-controlled driving mode. The technology still has a long way to go, mainly because the advances in vision and depth measurement sensors such as LIDARs can not achieve the levels of safety needed to make fully autonomous cars. Progress on this front is being made every day, and it seems inevitable that they will be readily available in the near future. Our team aims to further investigate the application of Computer Vision and sensor fusion to achieve independent self-driving without external guides. To accomplish this, we combine a depth camera with a LiDAR to provide better coverage of the surroundings and allow more accurate detection and thus accurate avoidance of obstacles. We are mounting the vision system on a model driverless car and using the vision data to guide the car control system. A computer vision algorithm will be run by the NVIDIA Jetson Nano to determine what course of action the car should take. The final prototype should be capable of driving at a reasonable speed without colliding with any objects and making decisions such as braking or turning when necessary

    The Structure and Psychometric Properties of Wellness for A Sample of Teachers in Egypt

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    The present study attempts to examine the structure of wellness for a sample of teachers in Egypt and examine psychometric properties of wellness Inventory. The study questions addressed are: is the structure of wellness multidimensional or uni-dimensional?, Is wellness inventory has appropriate psychometric properties?. A total of 417 teachers from Egypt completed the inventory of wellness, including males (N= 260) and females (N= 157).The teachers ranged in age from 29 to 48 with an average age 36.7 and S.D. 1.7 .  The inventory that used in this study is referred to as the multidimensional organizational wellness inventory (MOWI) (Fasone, 2017), Confirmatory factor analysis (CFA) is used. The results indicates that The structure of wellness is multidimensional which includes physical, emotional, social, intellectual, spiritual, occupational , and environmental. And the inventory has appropriate psychometric properties. Keywords: Wellness, Reliability, Construct Validity DOI: 10.7176/RHSS/9-16-04 Publication date: August 31st 201

    Unrealistic Optimism Among a Sample of University Students in Egypt and Saudi Arabia (Cross-cultural Study)

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    The present study considered as cross-cultural study attempts to examine the psychometric properties of unrealistic optimism in light of the scale used in the study for Egyptian and Saudi Arabia university students and Is the measurement equivalent of the scale terms for Egyptian and Saudi Arabia university students? . A total of (336) male students from university in Egypt and in Saudi Arabia from different specialties completed the scale of unrealistic optimism (prepared by the researchers), Confirmatory factor analysis (CFA) is used. The results indicate that the structure of model of unrealistic optimism is fit and the scale has appropriate psychometric properties. And the result indicate that the unrealistic optimism scale  have the same structure in Egypt and Saudi Arabia , that means the factorial invariance of unrealistic optimism in Egypt and Saudi Arabia . Keywords: Unrealistic optimism, Reliability, Construct validity, Cultural differences. DOI: 10.7176/RHSS/9-24-12 Publication date: December 31st 2019

    Global variation in diabetes diagnosis and prevalence based on fasting glucose and hemoglobin A1c

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    Fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) are both used to diagnose diabetes, but these measurements can identify different people as having diabetes. We used data from 117 population-based studies and quantified, in different world regions, the prevalence of diagnosed diabetes, and whether those who were previously undiagnosed and detected as having diabetes in survey screening, had elevated FPG, HbA1c or both. We developed prediction equations for estimating the probability that a person without previously diagnosed diabetes, and at a specific level of FPG, had elevated HbA1c, and vice versa. The age-standardized proportion of diabetes that was previously undiagnosed and detected in survey screening ranged from 30% in the high-income western region to 66% in south Asia. Among those with screen-detected diabetes with either test, the age-standardized proportion who had elevated levels of both FPG and HbA1c was 29-39% across regions; the remainder had discordant elevation of FPG or HbA1c. In most low- and middle-income regions, isolated elevated HbA1c was more common than isolated elevated FPG. In these regions, the use of FPG alone may delay diabetes diagnosis and underestimate diabetes prevalence. Our prediction equations help allocate finite resources for measuring HbA1c to reduce the global shortfall in diabetes diagnosis and surveillance

    Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018 population-based measurement studies with 88.6 million participants

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    © The Author(s) 2018. Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean diastolic blood pressure (DBP) and prevalence of raised blood pressure by sex and 10-year age group from 20-29 years to 70-79 years in each study, taking into account complex survey design and survey sample weights, where relevant. We used a linear mixed effect model to quantify the association between (probittransformed) prevalence of raised blood pressure and age-group- and sex-specific mean blood pressure. We calculated the contributions of change in mean SBP and DBP, and of change in the prevalence-mean association, to the change in prevalence of raised blood pressure. Results: In 2005-16, at the same level of population mean SBP and DBP, men and women in South Asia and in Central Asia, the Middle East and North Africa would have the highest prevalence of raised blood pressure, and men and women in the highincome Asia Pacific and high-income Western regions would have the lowest. In most region-sex-age groups where the prevalence of raised blood pressure declined, one half or more of the decline was due to the decline in mean blood pressure. Where prevalence of raised blood pressure has increased, the change was entirely driven by increasing mean blood pressure, offset partly by the change in the prevalence-mean association. Conclusions: Change in mean blood pressure is the main driver of the worldwide change in the prevalence of raised blood pressure, but change in the high-blood-pressure tail of the distribution has also contributed to the change in prevalence, especially in older age groups

    Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

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    Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

    Search for single production of vector-like quarks decaying into a b quark and a W boson in proton-proton collisions at root s=13 TeV

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    Measurement of the top quark mass using single top quark events in proton-proton collisions at root s=8 TeV

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    Search for Evidence of the Type-III Seesaw Mechanism in Multilepton Final States in Proton-Proton Collisions at root s=13 TeV

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