26 research outputs found

    FIRST REPORT OF COMMON BEAN FLOWER THRIPS Megalurothrips usitatus Bagnall IN COSTA RICA

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    Background: The species Megalurothrips usitatus is a thrips insect that has been recorded in Asia, Oceania, Australia and recently in America, attacking legume crops. Objective: to report Megalurothrips usitatus as species associated with flowers of common bean plants in Costa Rica. Methodology: the thrips from three growing bean locations were sampled and characterized through light microscopy in Costa Rica. Furthermore, a phylogenetic analysis of the COI gene compared with the databases of the National Center for Biotechnology Information (NCBI) was performed. Results: The species was recorded in three bean growing areas (Sardinal of Guanacaste, Estación Experimental Agrícola Fabio Baudrit Moreno in Alajuela and La Managua in Quepos). Implications: the new report of the insect in flowers of Phaseolus vulgaris implies future monitoring actions and respective integrated management; ignoring thrips populations could cause losses in the bean's regional production. Conclusion: the bean flower thrips is reported for the first time in Costa Rica

    Improving Error Detection in Deep Learning Based Radiotherapy Autocontouring Using Bayesian Uncertainty

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    Bayesian Neural Nets (BNN) are increasingly used for robust organ auto-contouring. Uncertainty heatmaps extracted from BNNs have been shown to correspond to inaccurate regions. To help speed up the mandatory quality assessment (QA) of contours in radiotherapy, these heatmaps could be used as stimuli to direct visual attention of clinicians to potential inaccuracies. In practice, this is non-trivial to achieve since many accurate regions also exhibit uncertainty. To influence the output uncertainty of a BNN, we propose a modified accuracy-versus-uncertainty (AvU) metric as an additional objective during model training that penalizes both accurate regions exhibiting uncertainty as well as inaccurate regions exhibiting certainty. For evaluation, we use an uncertainty-ROC curve that can help differentiate between Bayesian models by comparing the probability of uncertainty in inaccurate versus accurate regions. We train and evaluate a FlipOut BNN model on the MICCAI2015 Head and Neck Segmentation challenge dataset and on the DeepMind-TCIA dataset, and observed an increase in the AUC of uncertainty-ROC curves by 5.6% and 5.9%, respectively, when using the AvU objective. The AvU objective primarily reduced false positives regions (uncertain and accurate), drawing less visual attention to these regions, thereby potentially improving the speed of error detection.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Computer Graphics and VisualisationPattern Recognition and Bioinformatic

    Comparing Bayesian models for organ contouring in head and neck radiotherapy

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    Deep learning models for organ contouring in radiotherapy are poised for clinical usage, but currently, there exist few tools for automated quality assessment (QA) of the predicted contours. Bayesian models and their associated uncertainty, can potentially automate the process of detecting inaccurate predictions. We investigate two Bayesian models for auto-contouring, DropOut and FlipOut, using a quantitative measure – expected calibration error (ECE) and a qualitative measure – region-based accuracy-vs-uncertainty (R-AvU) graphs. It is well understood that a model should have low ECE to be considered trustworthy. However, in a QA context, a model should also have high uncertainty in inaccurate regions and low uncertainty in accurate regions. Such behaviour could direct visual attention of expert users to potentially inaccurate regions, leading to a speed-up in the QA process. Using R-AvU graphs, we qualitatively compare the behaviour of different models in accurate and inaccurate regions. Experiments are conducted on the MICCAI2015 Head and Neck Segmentation Challenge and on the DeepMindTCIA CT dataset using three models: DropOut-DICE, Dropout-CE (Cross Entropy) and FlipOut-CE. Quantitative results show that DropOut-DICE has the highest ECE, while Dropout-CE and FlipOut-CE have the lowest ECE. To better understand the difference between DropOut-CE and FlipOut-CE, we use the R-AvU graph which shows that FlipOut-CE has better uncertainty coverage in inaccurate regions than DropOut-CE. Such a combination of quantitative and qualitative metrics explores a new approach that helps to select which model can be deployed as a QA tool in clinical settings.<br/
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