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Collaborating Authors

 Lee, Junha


Self-Supervised Learning with Probabilistic Density Labeling for Rainfall Probability Estimation

arXiv.org Artificial Intelligence

Numerical weather prediction (NWP) models are fundamental in meteorology for simulating and forecasting the behavior of various atmospheric variables. The accuracy of precipitation forecasts and the acquisition of sufficient lead time are crucial for preventing hazardous weather events. However, the performance of NWP models is limited by the nonlinear and unpredictable patterns of extreme weather phenomena driven by temporal dynamics. In this regard, we propose a \textbf{S}elf-\textbf{S}upervised \textbf{L}earning with \textbf{P}robabilistic \textbf{D}ensity \textbf{L}abeling (SSLPDL) for estimating rainfall probability by post-processing NWP forecasts. Our post-processing method uses self-supervised learning (SSL) with masked modeling for reconstructing atmospheric physics variables, enabling the model to learn the dependency between variables. The pre-trained encoder is then utilized in transfer learning to a precipitation segmentation task. Furthermore, we introduce a straightforward labeling approach based on probability density to address the class imbalance in extreme weather phenomena like heavy rain events. Experimental results show that SSLPDL surpasses other precipitation forecasting models in regional precipitation post-processing and demonstrates competitive performance in extending forecast lead times. Our code is available at https://github.com/joonha425/SSLPDL


3D Geometric Shape Assembly via Efficient Point Cloud Matching

arXiv.org Artificial Intelligence

To this end, we et al., 2023b) to address the task of shape assembly, but these introduce Proxy Match Transform (PMT), an methods fall short of achieving accurate assembly. They approximate high-order feature transform layer typically represent each part as a global embedding and that enables reliable matching between mating perform regression to predict a placement for each part. The surfaces of parts while incurring low costs in global encoding strategy for each part, while simplifying memory and computation. Building upon PMT, the process, greatly limits local information by collapsing we introduce a new framework, dubbed Proxy spatial resolutions, which is necessary to localize the mating Match TransformeR (PMTR), for the geometric surface. Indeed, accurate shape assembly requires a detailed assembly task. We evaluate the proposed PMTR analysis of both fine-and coarse-level spatial information on the large-scale 3D geometric shape assembly of the parts in recognizing mating surfaces and establishing benchmark dataset of Breaking Bad and demonstrate correspondences between the surfaces. Therefore, a its superior performance and efficiency compared promising approach would be to retain the spatially rich to state-of-the-art methods. Project page: part representations during the encoding phase and analyze https://nahyuklee.github.io/pmtr.


CAT: Contrastive Adapter Training for Personalized Image Generation

arXiv.org Artificial Intelligence

The emergence of various adapters, including Low-Rank Adaptation (LoRA) applied from the field of natural language processing, has allowed diffusion models to personalize image generation at a low cost. However, due to the various challenges including limited datasets and shortage of regularization and computation resources, adapter training often results in unsatisfactory outcomes, leading to the corruption of the backbone model's prior knowledge. One of the well known phenomena is the loss of diversity in object generation, especially within the same class which leads to generating almost identical objects with minor variations. This poses challenges in generation capabilities. To solve this issue, we present Contrastive Adapter Training (CAT), a simple yet effective strategy to enhance adapter training through the application of CAT loss. Our approach facilitates the preservation of the base model's original knowledge when the model initiates adapters. Furthermore, we introduce the Knowledge Preservation Score (KPS) to evaluate CAT's ability to keep the former information. We qualitatively and quantitatively compare CAT's improvement. Finally, we mention the possibility of CAT in the aspects of multi-concept adapter and optimization.


Self-Supervised Pre-Training for Precipitation Post-Processor

arXiv.org Artificial Intelligence

Obtaining a sufficient forecast lead time for local precipitation is essential in preventing hazardous weather events. Global warming-induced climate change increases the challenge of accurately predicting severe precipitation events, such as heavy rainfall. In this paper, we propose a deep learning-based precipitation post-processor for numerical weather prediction (NWP) models. The precipitation post-processor consists of (i) employing self-supervised pre-training, where the parameters of the encoder are pre-trained on the reconstruction of the masked variables of the atmospheric physics domain; and (ii) conducting transfer learning on precipitation segmentation tasks (the target domain) from the pre-trained encoder. In addition, we introduced a heuristic labeling approach to effectively train class-imbalanced datasets. Our experiments on precipitation correction for regional NWP show that the proposed method outperforms other approaches.


High-dimensional Convolutional Networks for Geometric Pattern Recognition

arXiv.org Machine Learning

Many problems in science and engineering can be formulated in terms of geometric patterns in high-dimensional spaces. We present high-dimensional convolutional networks (ConvNets) for pattern recognition problems that arise in the context of geometric registration. We first study the effectiveness of convolutional networks in detecting linear subspaces in high-dimensional spaces with up to 32 dimensions: much higher dimensionality than prior applications of ConvNets. We then apply high-dimensional ConvNets to 3D registration under rigid motions and image correspondence estimation. Experiments indicate that our high-dimensional ConvNets outperform prior approaches that relied on deep networks based on global pooling operators.