Improving Convolutional Neural Networks for Cosmological Fields with Random Permutation

Fuente: arXiv
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Autores principales: Zhong, Kunhao, Gatti, Marco, Jain, Bhuvnesh
Formato: Preprint
Publicado: 2024
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author Zhong, Kunhao
Gatti, Marco
Jain, Bhuvnesh
author_facet Zhong, Kunhao
Gatti, Marco
Jain, Bhuvnesh
contents Convolutional Neural Networks (CNNs) have recently been applied to cosmological fields -- weak lensing mass maps and galaxy maps. However, cosmological maps differ in several ways from the vast majority of images that CNNs have been tested on: they are stochastic, typically low signal-to-noise per pixel, and with correlations on all scales. Further, the cosmology goal is a regression problem aimed at inferring posteriors on parameters that must be unbiased. We explore simple CNN architectures and present a novel approach of regularization and data augmentation to improve its performance for lensing mass maps. We find robust improvement by using a mixture of pooling and shuffling of the pixels in the deep layers. The random permutation regularizes the network in the low signal-to-noise regime and effectively augments the existing data. We use simulation-based inference (SBI) to show that the model outperforms CNN designs in the literature. We find a 30% improvement in the constraints of the $S_8$ parameter for simulated Stage-III surveys, including systematic uncertainties such as intrinsic alignments. We explore various statistical errors corresponding to next-generation surveys and find comparable improvements. We expect that our approach will have applications to other cosmological fields as well, such as galaxy maps or 21-cm maps.
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id arxiv_https___arxiv_org_abs_2403_01368
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publishDate 2024
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spellingShingle Improving Convolutional Neural Networks for Cosmological Fields with Random Permutation
Zhong, Kunhao
Gatti, Marco
Jain, Bhuvnesh
Cosmology and Nongalactic Astrophysics
Convolutional Neural Networks (CNNs) have recently been applied to cosmological fields -- weak lensing mass maps and galaxy maps. However, cosmological maps differ in several ways from the vast majority of images that CNNs have been tested on: they are stochastic, typically low signal-to-noise per pixel, and with correlations on all scales. Further, the cosmology goal is a regression problem aimed at inferring posteriors on parameters that must be unbiased. We explore simple CNN architectures and present a novel approach of regularization and data augmentation to improve its performance for lensing mass maps. We find robust improvement by using a mixture of pooling and shuffling of the pixels in the deep layers. The random permutation regularizes the network in the low signal-to-noise regime and effectively augments the existing data. We use simulation-based inference (SBI) to show that the model outperforms CNN designs in the literature. We find a 30% improvement in the constraints of the $S_8$ parameter for simulated Stage-III surveys, including systematic uncertainties such as intrinsic alignments. We explore various statistical errors corresponding to next-generation surveys and find comparable improvements. We expect that our approach will have applications to other cosmological fields as well, such as galaxy maps or 21-cm maps.
title Improving Convolutional Neural Networks for Cosmological Fields with Random Permutation
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2403.01368