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Impact of weather factors on migration intention using machine learning algorithms

arXiv.org Artificial Intelligence

A growing attention in the empirical literature has been paid to the incidence of climate shocks and change in migration decisions. Previous literature leads to different results and uses a multitude of traditional empirical approaches. This paper proposes a tree-based Machine Learning (ML) approach to analyze the role of the weather shocks towards an individual's intention to migrate in the six agriculture-dependent-economy countries such as Burkina Faso, Ivory Coast, Mali, Mauritania, Niger, and Senegal. We perform several tree-based algorithms (e.g., XGB, Random Forest) using the train-validation-test workflow to build robust and noise-resistant approaches. Then we determine the important features showing in which direction they are influencing the migration intention. This ML-based estimation accounts for features such as weather shocks captured by the Standardized Precipitation-Evapotranspiration Index (SPEI) for different timescales and various socioeconomic features/covariates. We find that (i) weather features improve the prediction performance although socioeconomic characteristics have more influence on migration intentions, (ii) country-specific model is necessary, and (iii) international move is influenced more by the longer timescales of SPEIs while general move (which includes internal move) by that of shorter timescales.


Mitigating Bias in Federated Learning

arXiv.org Machine Learning

As machine learning (ML) has been applied to facilitate decision-making in various areas, such as hiring, loan grading etc., there have been and continue to be increasing concerns [3, 31] that ML models will inevitably "learn undesired bias" from the training data and make unfair predictions. From algorithms erroneously detecting suspects of crimes base on the color of their skin [7] and deciding who goes to jail [26], to algorithms used to predict test scores that provide unfairly higher scores to socioeconomically privileged students, allowing them to enter universities at a higher rate [27], the lack of understanding and control of undesired bias in ML models has tangible consequences. To deal with this challenge of biased models, many researchers have devoted their efforts, e.g., [15, 17, 35, 8, 2] to define, detect and mitigate bias in ML over the past decade. These approaches mainly measure and reduce undesired bias with respect to a sensitive attribute, such as age or race, in the training dataset. Although many of them provide various effective approaches, they all focus on centralized ML, where the training dataset is stored in a single place, executing the learning procedure, and hence assume full access to the entire dataset.


As coronavirus spread in Wuhan, China's secret deals with businesses caused major testing blunders

The Japan Times

WUHAN, China – In the early days in Wuhan, the first city first struck by the virus, getting a COVID-19 test was so difficult that residents compared it to winning the lottery. Throughout the Chinese city in January, thousands of people waited in hourslong lines for hospitals, sometimes next to corpses lying in hallways. But most couldn't get the test they needed to be admitted as patients. And for the few who did, the tests were often faulty, resulting in false negatives. The widespread test shortages and problems at a time when the virus could have been slowed were caused largely by secrecy and cronyism at China's top disease control agency, an Associated Press investigation has found. The flawed testing system prevented scientists and officials from seeing how fast the virus was spreading -- another way China fumbled its early response to the virus. Earlier reporting showed how top Chinese leaders delayed warning the public and withheld information from the World Health Organization, supplying the most comprehensive picture yet of China's initial missteps. Taken together, these mistakes in January facilitated the virus's spread through Wuhan and across the world undetected, in a pandemic that has now sickened more than 64 million people and killed almost 1.5 million.


Obstacle Avoidance Using a Monocular Camera

arXiv.org Artificial Intelligence

A collision avoidance system based on simple digital cameras would help enable the safe integration of small UAVs into crowded, low-altitude environments. In this work, we present an obstacle avoidance system for small UAVs that uses a monocular camera with a hybrid neural network and path planner controller. The system is comprised of a vision network for estimating depth from camera images, a high-level control network, a collision prediction network, and a contingency policy. This system is evaluated on a simulated UAV navigating an obstacle course in a constrained flight pattern. Results show the proposed system achieves low collision rates while maintaining operationally relevant flight speeds.


Attention-gating for improved radio galaxy classification

arXiv.org Artificial Intelligence

In this work we introduce attention as a state of the art mechanism for classification of radio galaxies using convolutional neural networks. We present an attention-based model that performs on par with previous classifiers while using more than 50\% fewer parameters than the next smallest classic CNN application in this field. We demonstrate quantitatively how the selection of normalisation and aggregation methods used in attention-gating can affect the output of individual models, and show that the resulting attention maps can be used to interpret the classification choices made by the model. We observe that the salient regions identified by the our model align well with the regions an expert human classifier would attend to make equivalent classifications. We show that while the selection of normalisation and aggregation may only minimally affect the performance of individual models, it can significantly affect the interpretability of the respective attention maps and by selecting a model which aligns well with how astronomers classify radio sources by eye, a user can employ the model in a more effective manner.


Classifying bacteria clones using attention-based deep multiple instance learning interpreted by persistence homology

arXiv.org Artificial Intelligence

In this work, we analyze if it is possible to distinguish between different clones of the same bacteria species (Klebisiella pneumoniae) based only on microscopic images. It is a challenging task, previously considered impossible due to the high clones' similarity. For this purpose, we apply a multi-step algorithm with attention-based multiple instance learning. Except for obtaining accuracy at the level of 0.9, we introduce extensive interpretability based on CellProfiler and persistence homology, increasing the understandability and trust in the model.


VisEvol: Visual Analytics to Support Hyperparameter Search through Evolutionary Optimization

arXiv.org Machine Learning

During the training phase of machine learning (ML) models, it is usually necessary to configure several hyperparameters. This process is computationally intensive and requires an extensive search to infer the best hyperparameter set for the given problem. The challenge is exacerbated by the fact that most ML models are complex internally, and training involves trial-and-error processes that could remarkably affect the predictive result. Moreover, each hyperparameter of an ML algorithm is potentially intertwined with the others, and changing it might result in unforeseeable impacts on the remaining hyperparameters. Evolutionary optimization is a promising method to try and address those issues. According to this method, performant models are stored, while the remainder are improved through crossover and mutation processes inspired by genetic algorithms. We present VisEvol, a visual analytics tool that supports interactive exploration of hyperparameters and intervention in this evolutionary procedure. In summary, our proposed tool helps the user to generate new models through evolution and eventually explore powerful hyperparameter combinations in diverse regions of the extensive hyperparameter space. The outcome is a voting ensemble (with equal rights) that boosts the final predictive performance. The utility and applicability of VisEvol are demonstrated with two use cases and interviews with ML experts who evaluated the effectiveness of the tool.


Unsupervised Anomaly Detection From Semantic Similarity Scores

arXiv.org Artificial Intelligence

The approach is based on learning a semantic similarity measure to find for a given test example the semantically closest example in the training set and then using a discriminator to classify whether the two examples show sufficient semantic dissimilarity such that the test example can be rejected as OOD. We are able to outperform previous approaches for anomaly, novelty, or out-of-distribution detection in the visual domain by a large margin. In particular we obtain AUROC values close to one for the challenging task of detecting examples from CIFAR-10 as out-of-distribution given CIFAR-100 as in-distribution, without making use of label information. Anomaly detection or novelty detection aims at identifying patterns in data that are significantly different to what is expected. This problem is inherently a binary classification problem that classifies examples either as in-distribution or out-of-distribution, given a sufficiently large sample from the in-distribution (training set). A natural approach to OOD detection is to learn a density model from the training data and compute the likelihood ratio of OOD examples to in-distribution examples.


Confluence: A Robust Non-IoU Alternative to Non-Maxima Suppression in Object Detection

arXiv.org Artificial Intelligence

This paper presents a novel alternative to Greedy Non-Maxima Suppression (NMS) in the task of bounding box selection and suppression in object detection. It proposes Confluence, an algorithm which does not rely solely on individual confidence scores to select optimal bounding boxes, nor does it rely on Intersection Over Union (IoU) to remove false positives. Using Manhattan Distance, it selects the bounding box which is closest to every other bounding box within the cluster and removes highly confluent neighboring boxes. Thus, Confluence represents a paradigm shift in bounding box selection and suppression as it is based on fundamentally different theoretical principles to Greedy NMS and its variants. Confluence is experimentally validated on RetinaNet, YOLOv3 and Mask-RCNN, using both the MS COCO and PASCAL VOC 2007 datasets. Confluence outperforms Greedy NMS in both mAP and recall on both datasets, using the challenging 0.50:0.95 mAP evaluation metric. On each detector and dataset, mAP was improved by 0.3-0.7% while recall was improved by 1.4-2.5%. A theoretical comparison of Greedy NMS and the Confluence Algorithm is provided, and quantitative results are supported by extensive qualitative results analysis. Furthermore, sensitivity analysis experiments across mAP thresholds support the conclusion that Confluence is more robust than NMS.


Learning a metacognition for object perception

arXiv.org Artificial Intelligence

Beyond representing the external world, humans also represent their own cognitive processes. In the context of perception, this metacognition helps us identify unreliable percepts, such as when we recognize that we are seeing an illusion. Here we propose MetaGen, a model for the unsupervised learning of metacognition. In MetaGen, metacognition is expressed as a generative model of how a perceptual system produces noisy percepts. Using basic principles of how the world works (such as object permanence, part of infants' core knowledge), MetaGen jointly infers the objects in the world causing the percepts and a representation of its own perceptual system. MetaGen can then use this metacognition to infer which objects are actually present in the world. On simulated data, we find that MetaGen quickly learns a metacognition and improves overall accuracy, outperforming models that lack a metacognition.