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ExtremeWeather: A large-scale climate dataset for semi-supervised detection, localization, and understanding of extreme weather events

Neural Information Processing Systems

Then detection and identification of extreme weather events in large-scale climate simulations is an important problem for risk management, informing governmental policy decisions and advancing our basic understanding of the climate system. Recent work has shown that fully supervised convolutional neural networks (CNNs) can yield acceptable accuracy for classifying well-known types of extreme weather events when large amounts of labeled data are available. However, many different types of spatially localized climate patterns are of interest including hurricanes, extra-tropical cyclones, weather fronts, and blocking events among others. Existing labeled data for these patterns can be incomplete in various ways, such as covering only certain years or geographic areas and having false negatives. This type of climate data therefore poses a number of interesting machine learning challenges. We present a multichannel spatiotemporal CNN architecture for semi-supervised bounding box prediction and exploratory data analysis. We demonstrate that our approach is able to leverage temporal information and unlabeled data to improve the localization of extreme weather events. Further, we explore the representations learned by our model in order to better understand this important data. We present a dataset, ExtremeWeather, to encourage machine learning research in this area and to help facilitate further work in understanding and mitigating the effects of climate change.



An Enhanced Projection Pursuit Tree Classifier with Visual Methods for Assessing Algorithmic Improvements

da Silva, Natalia, Cook, Dianne, Lee, Eun-Kyung

arXiv.org Machine Learning

This paper presents enhancements to the projection pursuit tree classifier and visual diagnostic methods for assessing their impact in high dimensions. The original algorithm uses linear combinations of variables in a tree structure where depth is constrained to be less than the number of classes -- a limitation that proves too rigid for complex classification problems. Our extensions improve performance in multi-class settings with unequal variance-covariance structures and nonlinear class separations by allowing more splits and more flexible class groupings in the projection pursuit computation. Proposing algorithmic improvements is straightforward; demonstrating their actual utility is not. We therefore develop two visual diagnostic approaches to verify that the enhancements perform as intended. Using high-dimensional visualization techniques, we examine model fits on benchmark datasets to assess whether the algorithm behaves as theorized. An interactive web application enables users to explore the behavior of both the original and enhanced classifiers under controlled scenarios. The enhancements are implemented in the R package PPtreeExt.



ed519dacc89b2bead3f453b0b05a4a8b-Supplemental.pdf

Neural Information Processing Systems

Figure 11: Comparison of HCAM (labeled as HTM) with different chunk sizes to TrXL across the different ballet levels. The performance of the HCAM model is robust to varying chunk size, indicating that HCAM does not need a task-relevant segmentation to perform well.


bc218a0c656e49d4b086975a9c785f47-Supplemental-Datasets_and_Benchmarks.pdf

Neural Information Processing Systems

Emerging ethical approaches have attempted to filter pretraining material, but such approaches have been ad hoc and failed to take context into account. We offer an approach to filtering grounded in law, which has directly addressed the tradeoffs in filtering material.




c39e1a03859f9ee215bc49131d0caf33-Supplemental.pdf

Neural Information Processing Systems

Additionally, we show generalization performance of our proposed method across differentvisualdomains. Withthegiven problemcategory(task),asubsetforlearning can be sampled (via domain episode module in Figure 4 in main text). Here, by replacingclass with task, K-shot andN-task reasoning framework can be defined. Here, we show analogical learning with the existing meta learning framework for fast adaptation fromthesourcedomain tothetargetdomain.


8cbe9ce23f42628c98f80fa0fac8b19a-Supplemental.pdf

Neural Information Processing Systems

After training for 200 epochs, we achieve the attack success rate (ASR) of99.97% and the natural accuracy on clean data (ACC)of93.73%. Blend attack [6]: We first generate a trigger pattern where each pixel value is sampled from auniform distribution in[0,255]asshowninFigure 6(c). Input-aware Attack (IAB) [30]: The dynamic trigger varies across samples as shown in Figure 6(d). We apply two types of target label selection. Clean-labelAttack(CLB)[42]: The trigger is a3 3checkerboard at the four corners of images as shown in Figure 7(b).