41 research outputs found

    Exposing the Unseen: Exposure Time Emulation for Offline Benchmarking of Vision Algorithms

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    Visual Odometry (VO) is one of the fundamental tasks in computer vision for robotics. However, its performance is deeply affected by High Dynamic Range (HDR) scenes, omnipresent outdoor. While new Automatic-Exposure (AE) approaches to mitigate this have appeared, their comparison in a reproducible manner is problematic. This stems from the fact that the behavior of AE depends on the environment, and it affects the image acquisition process. Consequently, AE has traditionally only been benchmarked in an online manner, making the experiments non-reproducible. To solve this, we propose a new methodology based on an emulator that can generate images at any exposure time. It leverages BorealHDR, a unique multi-exposure stereo dataset collected over 8.4 km, on 50 trajectories with challenging illumination conditions. Moreover, it contains pose ground truth for each image and a global 3D map, based on lidar data. We show that using these images acquired at different exposure times, we can emulate realistic images keeping a Root-Mean-Square Error (RMSE) below 1.78 % compared to ground truth images. To demonstrate the practicality of our approach for offline benchmarking, we compared three state-of-the-art AE algorithms on key elements of Visual Simultaneous Localization And Mapping (VSLAM) pipeline, against four baselines. Consequently, reproducible evaluation of AE is now possible, speeding up the development of future approaches. Our code and dataset are available online at this link: https://github.com/norlab-ulaval/BorealHDRComment: 6 pages, 6 figures, submitted to 2024 IEEE International Conference on Robotics and Automation (ICRA 2024

    Effect of Family Medicine Groups on Visits to the Emergency Department among Diabetics in Quebec between 2000 and 2011: A Population-Based Segmented Regression Analysis of an Interrupted Time Series

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    Poster Presentation Background: Family Medicine Groups (FMG) were introduced in Quebec in 2002 to reorganize primary care practices and encourage team-based and inter-professional approaches to service delivery. We measured the effect of this reform on the rate of emergency department (ED) visits among patients diagnosed with diabetes. Methods: Administrative databases were used to derive the weekly rate of ED visits between April 1, 2000 and March 31, 2012. We performed an interrupted segmented regression analysis to derive the estimated and extrapolated rates of visits in the years following the initial reform implementation. We employed an outcome control series of diabetics visiting the ED to treat appendicitis to strengthen the study’s internal validity. Results: A gradual decline in the rate of visits was observed for short term diabetes related complications and total ED visits. After 9 years of reform implementation, we observed a reduction of 1.42 and 1.70 ED visits per 10,000 diabetics to treat short term complications in urban and rural areas, respectively. A steady decrease was also observed in the total rate of ED visits in urban areas where we observed a reduction of 6.72 visits per 10,000 diabetics 9 years following the reform. Visits coded for appendicitis showed no clinically relevant changes over the study period. Interpretation: Our results suggest that the decreases in the rate of ED visits are attributed to the implementation of the FMG model across the province. The steady decline in the rate of total ED visits in urban areas is of particular relevance where overutilization of the ED is a problem. Evidence of these decreases despite the low-intensity nature of the FMG reform suggests the potential for this model to act as a future platform for implementing comprehensive care models for chronic disease management

    Current Practices for Preventive Maintenance and Expectations for Predictive Maintenance in East-Canadian Mines

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    ABSTRACT: Preventive maintenance practices have been proven to reduce maintenance costs in many industries. In the mining industry, preventive maintenance is the main form of maintenance, especially for mobile equipment. With the increase of sensor data and the installation of wireless infrastructure within underground mines, predictive maintenance practices are beginning to be applied to the mining equipment maintenance process. However, for the transition from preventive to predictive maintenance to succeed, researchers must first understand the maintenance process implemented in mines. In this paper, we conducted interviews with 15 maintenance experts from 7 mining sites (6 gold, 1 diamond) across East-Canada to investigate the maintenance planning process currently implemented in Canadian mines. We documented experts’ feedback on the process, their expectations regarding the introduction of predictive maintenance in mining, and the usability of existing computerized maintenance management software (CMMS). From our results, we compiled a summary of actual maintenance practices and showed how they differ from theoretical practices. Finally, we list the Key Performance Indicators (KPIs) relevant for maintenance planning and user requirements to improve the usability of CMMS

    Determination of the standard deviation for proficiency assessment from past participant’s performances

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    The “uncertainty function” introduced by Thompson et al. estimates the reproducibility standard deviation (SR) as a function of concentration. This model was successfully applied to a data set derived from three proficiency testing schemes aiming at the quantification of three toxic elements (cadmium, lead and mercury) in blood and urine. A threshold concentration was determined for each element. Below this concentration SR is found to be constant, while above it the reproducibility relative standard deviation is constant. This model allows the a priori estimation of standard deviation for performance assessment for proficiency testing rounds.JRC.D.5-Standards for Food Bioscienc

    Determination of the standard deviation for proficiency assessment from past participant's performances

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    The "uncertainty function" introduced by Thompson et al. estimates the reproducibility standard deviation as a function of concentration or mass fraction. This model was successfully applied to data derived from three proficiency testing schemes aiming at the quantification of cadmium, lead and mercury in blood and urine. This model allows the estimation of standard deviation for the performance assessment for proficiency testing rounds

    Influence of social and material individual and area deprivation on suicide mortality among 2.7 million Canadians: a prospective study

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    Abstract Background: Few studies have investigated how area-level deprivation influences the relationship between individual disadvantage and suicide mortality. The aim of this study was to examine individual measures of material and social disadvantage in relation to suicide mortality in Canada and to determine whether these relationships were modified by area deprivation. Methods: Using the 1991-2001 Canadian Census Mortality Follow-up Study cohort (N = 2,685,400), measures of individual social (civil status, family structure, living alone) and material (education, income, employment) disadvantage were entered into Cox proportional hazard models to calculate hazard ratios (HR) and 95% confidence intervals (CI) for male and female suicide mortality. Two indices of area deprivation were computedone capturing social, and the other material, dimensions -and models were run separately for high versus low deprivation. Results: After accounting for individual and area characteristics, individual social and material disadvantage were associated with higher suicide mortality, especially for individuals not employed, not married, with low education and low income. Associations between social and material area deprivation and suicide mortality largely disappeared upon adjustment for individual-level disadvantage. In stratified analyses, suicide risk was greater for low income females in socially deprived areas and males living alone in materially deprived areas, and there was no evidence of other modifying effects of area deprivation. Conclusions: Individual disadvantage was associated with suicide mortality, particularly for males. With some exceptions, there was little evidence that area deprivation modified the influence of individual disadvantage on suicide risk. Prevention strategies should primarily focus on individuals who are unemployed or out of the labour force, and have low education or income. Individuals with low income or who are living alone in deprived areas should also be targeted

    The Public Repository of Xenografts enables discovery and randomized phase II-like trials in mice

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    More than 90% of drugs with preclinical activity fail in human trials, largely due to insufficient efficacy. We hypothesized that adequately powered trials of patient-derived xenografts (PDX) in mice could efficiently define therapeutic activity across heterogeneous tumors. To address this hypothesis, we established a large, publicly available repository of well-characterized leukemia and lymphoma PDXs that undergo orthotopic engraftment, called the Public Repository of Xenografts (PRoXe). PRoXe includes all de-identified information relevant to the primary specimens and the PDXs derived from them. Using this repository, we demonstrate that large studies of acute leukemia PDXs that mimic human randomized clinical trials can characterize drug efficacy and generate transcriptional, functional, and proteomic biomarkers in both treatment-naive and relapsed/refractory disease
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