publications

2024

1. 

   Multi-View Causal Representation Learning with Partial Observability

   Dingling Yao, Danru Xu , Sebastien Lachapelle , and 5 more authors

   The Twelfth International Conference on Learning Representations, 2024

   Abs arXiv Bib Website

   We present a unified framework for studying the identifiability of representations learned from simultaneously observed views, such as different data modalities. We allow a partially observed setting in which each view constitutes a nonlinear mixture of a subset of underlying latent variables, which can be causally related. We prove that the information shared across all subsets of any number of views can be learned up to a smooth bijection using contrastive learning and a single encoder per view. We also provide graphical criteria indicating which latent variables can be identified through a simple set of rules, which we refer to as identifiability algebra. Our general framework and theoretical results unify and extend several previous works on multi-view nonlinear ICA, disentanglement, and causal representation learning. We experimentally validate our claims on numerical, image, and multi- modal data sets. Further, we demonstrate that the performance of prior methods is recovered in different special cases of our setup. Overall, we find that access to multiple partial views enables us to identify a more fine-grained representation, under the generally milder assumption of partial observability.

   @article{yao2024multiview,
     title = {Multi-View Causal Representation Learning with Partial Observability},
     author = {Yao, Dingling and Xu, Danru and Lachapelle, Sebastien and Magliacane, Sara and Taslakian, Perouz and Martius, Georg and von K{\"u}gelgen, Julius and Locatello, Francesco},
     journal = {The Twelfth International Conference on Learning Representations},
     year = {2024},
   }

2. 

   A Sparsity Principle for Partially Observable Causal Representation Learning

   Danru Xu , Dingling Yao, Sebastien Lachapelle , and 4 more authors

   International Conference on Machine Learning, 2024

   Abs Bib Website

   Causal representation learning (CRL) aims at identifying high-level causal variables from low-level data, e.g. images. Most current methods assume that all causal variables are captured in the high-dimensional observations. The few exceptions assume multiple partial observations of the same state, or focus only on the shared causal representations across multiple domains. In this work, we focus on learning causal representations from data under partial observability, i.e., when some of the causal variables are masked and therefore not captured in the observations, the observations represent different underlying causal states and the set of masked variables changes across the different samples. We introduce two theoretical results for identifying causal variables in this setting by exploiting a sparsity regularizer. For linear mixing functions, we provide a theorem that allows us to identify the causal variables up to permutation and element-wise linear transformations without parametric assumptions on the underlying causal model. For piecewise linear mixing functions, we provide a similar result that allows us to identify Gaussian causal variables up to permutation and element-wise linear transformations. We test our theoretical results on simulated data, showing their effectiveness.

   @article{xu2023sparsity,
     title = {A Sparsity Principle for Partially Observable Causal Representation Learning},
     author = {Xu, Danru and Yao, Dingling and Lachapelle, Sebastien and Taslakian, Perouz and von K{\"u}gelgen, Julius and Locatello, Francesco and Magliacane, Sara},
     journal = {International Conference on Machine Learning},
     year = {2024},
   }

3. 

   Marrying Causal Representation Learning with Dynamical Systems for Science

   Dingling Yao, Caroline Muller , and Francesco Locatello

   Neural Information Processing Systems, 2024

   Abs arXiv Bib

   Causal representation learning promises to extend causal models to hidden causal variables from raw entangled measurements. However, most progress has focused on proving identifiability results in different settings, and we are not aware of any successful real-world application. At the same time, the field of dynamical systems benefited from deep learning and scaled to countless applications but does not allow parameter identification. In this paper, we draw a clear connection between the two and their key assumptions, allowing us to apply identifiable methods developed in causal representation learning to dynamical systems. At the same time, we can leverage scalable differentiable solvers developed for differential equations to build models that are both identifiable and practical. Overall, we learn explicitly controllable models that isolate the trajectory-specific parameters for further downstream tasks such as out-of-distribution classification or treatment effect estimation. We experiment with a wind simulator with partially known factors of variation. We also apply the resulting model to real-world climate data and successfully answer downstream causal questions in line with existing literature on climate change.

   @article{yao2024marrying,
     title = {Marrying Causal Representation Learning with Dynamical Systems for Science},
     author = {Yao, Dingling and Muller, Caroline and Locatello, Francesco},
     journal = {Neural Information Processing Systems},
     year = {2024},
   }

2021

1. 

   Active Learning in Gaussian Process State Space Model

   Hon Sum Alec Yu , Dingling Yao, Christoph Zimmer , and 2 more authors

   Machine Learning and Knowledge Discovery in Databases. Research Track: European Conference, ECML PKDD 2021, Bilbao, Spain, September 13–17, 2021, Proceedings, Part III 21, 2021

   Abs arXiv Bib Website

   We investigate active learning in Gaussian Process state-space models (GPSSM). Our problem is to actively steer the system through latent states by determining its inputs such that the underlying dynamics can be optimally learned by a GPSSM. In order that the most informative inputs are selected, we employ mutual information as our active learning criterion. In particular, we present two approaches for the approximation of mutual information for the GPSSM given latent states. The proposed approaches are evaluated in several physical systems where we actively learn the underlying non-linear dynamics represented by the state-space model.

   @article{yu2021active,
     title = {Active Learning in Gaussian Process State Space Model},
     author = {Yu, Hon Sum Alec and Yao, Dingling and Zimmer, Christoph and Toussaint, Marc and Nguyen-Tuong, Duy},
     journal = {Machine Learning and Knowledge Discovery in Databases. Research Track: European Conference, ECML PKDD 2021, Bilbao, Spain, September 13--17, 2021, Proceedings, Part III 21},
     pages = {346--361},
     year = {2021},
   }