Goto

Collaborating Authors

 North Ryde


Dark Energy Survey Year 3 results: Simulation-based $w$CDM inference from weak lensing and galaxy clustering maps with deep learning. I. Analysis design

Thomsen, A., Bucko, J., Kacprzak, T., Ajani, V., Fluri, J., Refregier, A., Anbajagane, D., Castander, F. J., Ferté, A., Gatti, M., Jeffrey, N., Alarcon, A., Amon, A., Bechtol, K., Becker, M. R., Bernstein, G. M., Campos, A., Rosell, A. Carnero, Chang, C., Chen, R., Choi, A., Crocce, M., Davis, C., DeRose, J., Dodelson, S., Doux, C., Eckert, K., Elvin-Poole, J., Everett, S., Fosalba, P., Gruen, D., Harrison, I., Herner, K., Huff, E. M., Jarvis, M., Kuropatkin, N., Leget, P. -F., MacCrann, N., McCullough, J., Myles, J., Navarro-Alsina, A., Pandey, S., Porredon, A., Prat, J., Raveri, M., Rodriguez-Monroy, M., Rollins, R. P., Roodman, A., Rykoff, E. S., Sánchez, C., Secco, L. F., Sheldon, E., Shin, T., Troxel, M. A., Tutusaus, I., Varga, T. N., Weaverdyck, N., Wechsler, R. H., Yanny, B., Yin, B., Zhang, Y., Zuntz, J., Allam, S., Andrade-Oliveira, F., Bacon, D., Blazek, J., Brooks, D., Camilleri, R., Carretero, J., Cawthon, R., da Costa, L. N., Pereira, M. E. da Silva, Davis, T. M., De Vicente, J., Desai, S., Doel, P., García-Bellido, J., Gutierrez, G., Hinton, S. R., Hollowood, D. L., Honscheid, K., James, D. J., Kuehn, K., Lahav, O., Lee, S., Marshall, J. L., Mena-Fernández, J., Menanteau, F., Miquel, R., Muir, J., Ogando, R. L. C., Malagón, A. A. Plazas, Sanchez, E., Cid, D. Sanchez, Sevilla-Noarbe, I., Smith, M., Suchyta, E., Swanson, M. E. C., Thomas, D., To, C., Tucker, D. L.

arXiv.org Artificial Intelligence

Data-driven approaches using deep learning are emerging as powerful techniques to extract non-Gaussian information from cosmological large-scale structure. This work presents the first simulation-based inference (SBI) pipeline that combines weak lensing and galaxy clustering maps in a realistic Dark Energy Survey Year 3 (DES Y3) configuration and serves as preparation for a forthcoming analysis of the survey data. We develop a scalable forward model based on the CosmoGridV1 suite of N-body simulations to generate over one million self-consistent mock realizations of DES Y3 at the map level. Leveraging this large dataset, we train deep graph convolutional neural networks on the full survey footprint in spherical geometry to learn low-dimensional features that approximately maximize mutual information with target parameters. These learned compressions enable neural density estimation of the implicit likelihood via normalizing flows in a ten-dimensional parameter space spanning cosmological $w$CDM, intrinsic alignment, and linear galaxy bias parameters, while marginalizing over baryonic, photometric redshift, and shear bias nuisances. To ensure robustness, we extensively validate our inference pipeline using synthetic observations derived from both systematic contaminations in our forward model and independent Buzzard galaxy catalogs. Our forecasts yield significant improvements in cosmological parameter constraints, achieving $2-3\times$ higher figures of merit in the $Ω_m - S_8$ plane relative to our implementation of baseline two-point statistics and effectively breaking parameter degeneracies through probe combination. These results demonstrate the potential of SBI analyses powered by deep learning for upcoming Stage-IV wide-field imaging surveys.


Unsupervised machine learning framework for discriminating major variants of concern during COVID-19

Chandra, Rohitash, Bansal, Chaarvi, Kang, Mingyue, Blau, Tom, Agarwal, Vinti, Singh, Pranjal, Wilson, Laurence O. W., Vasan, Seshadri

arXiv.org Artificial Intelligence

Due to the high mutation rate of the virus, the COVID-19 pandemic evolved rapidly. Certain variants of the virus, such as Delta and Omicron, emerged with altered viral properties leading to severe transmission and death rates. These variants burdened the medical systems worldwide with a major impact to travel, productivity, and the world economy. Unsupervised machine learning methods have the ability to compress, characterize, and visualize unlabelled data. This paper presents a framework that utilizes unsupervised machine learning methods to discriminate and visualize the associations between major COVID-19 variants based on their genome sequences. These methods comprise a combination of selected dimensionality reduction and clustering techniques. The framework processes the RNA sequences by performing a k-mer analysis on the data and further visualises and compares the results using selected dimensionality reduction methods that include principal component analysis (PCA), t-distributed stochastic neighbour embedding (t-SNE), and uniform manifold approximation projection (UMAP). Our framework also employs agglomerative hierarchical clustering to visualize the mutational differences among major variants of concern and country-wise mutational differences for selected variants (Delta and Omicron) using dendrograms. We also provide country-wise mutational differences for selected variants via dendrograms. We find that the proposed framework can effectively distinguish between the major variants and has the potential to identify emerging variants in the future.


Deep Stereo Matching With Explicit Cost Aggregation Sub-Architecture

Yu, Lidong (Beijing Institute of Technology) | Wang, Yucheng (Kandao Australia Research Center) | Wu, Yuwei (Beijing Institute of Technology) | Jia, Yunde (Beijing Institute of Technology)

AAAI Conferences

Deep neural networks have shown excellent performance for stereo matching. Many efforts focus on the feature extraction and similarity measurement of the matching cost computation step while less attention is paid on cost aggregation which is crucial for stereo matching. In this paper, we present a learning-based cost aggregation method for stereo matching by a novel sub-architecture in the end-to-end trainable pipeline. We reformulate the cost aggregation as a learning process of the generation and selection of cost aggregation proposals which indicate the possible cost aggregation results. The cost aggregation sub-architecture is realized by a two-stream network: one for the generation of cost aggregation proposals, the other for the selection of the proposals. The criterion for the selection is determined by the low-level structure information obtained from a light convolutional network. The two-stream network offers a global view guidance for the cost aggregation to rectify the mismatching value stemming from the limited view of the matching cost computation. The comprehensive experiments on challenge datasets such as KITTI and Scene Flow show that our method outperforms the state-of-the-art methods.


l1-norm Penalized Orthogonal Forward Regression

Hong, Xia, Chen, Sheng, Guo, Yi, Gao, Junbin

arXiv.org Machine Learning

A l1-norm penalized orthogonal forward regression (l1-POFR) algorithm is proposed based on the concept of leaveone- out mean square error (LOOMSE). Firstly, a new l1-norm penalized cost function is defined in the constructed orthogonal space, and each orthogonal basis is associated with an individually tunable regularization parameter. Secondly, due to orthogonal computation, the LOOMSE can be analytically computed without actually splitting the data set, and moreover a closed form of the optimal regularization parameter in terms of minimal LOOMSE is derived. Thirdly, a lower bound for regularization parameters is proposed, which can be used for robust LOOMSE estimation by adaptively detecting and removing regressors to an inactive set so that the computational cost of the algorithm is significantly reduced. Illustrative examples are included to demonstrate the effectiveness of this new l1-POFR approach.