10 research outputs found
Encoding Invariances in Deep Generative Models
Reliable training of generative adversarial networks (GANs) typically require massive datasets in order to model complicated distributions. However, in several applications, training samples obey invariances that are \textit{a priori} known; for example, in complex physics simulations, the training data obey universal laws encoded as well-defined mathematical equations. In this paper, we propose a new generative modeling approach, InvNet, that can efficiently model data spaces with known invariances. We devise an adversarial training algorithm to encode them into data distribution. We validate our framework in three experimental settings: generating images with fixed motifs; solving nonlinear partial differential equations (PDEs); and reconstructing two-phase microstructures with desired statistical properties. We complement our experiments with several theoretical results
A Deep Learning Framework for Design and Analysis of Surgical Bioprosthetic Heart Valves
Bioprosthetic heart valves (BHVs) are commonly used as heart valve replacements but they are prone to fatigue failure; estimating their remaining life directly from medical images is difficult. Analyzing the valve performance can provide better guidance for personalized valve design. However, such analyses are often computationally intensive. In this work, we introduce the concept of deep learning (DL) based finite element analysis (DLFEA) to learn the deformation biomechanics of bioprosthetic aortic valves directly from simulations. The proposed DL framework can eliminate the time-consuming biomechanics simulations, while predicting valve deformations with the same fidelity. We present statistical results that demonstrate the high performance of the DLFEA framework and the applicability of the framework to predict bioprosthetic aortic valve deformations. With further development, such a tool can provide fast decision support for designing surgical bioprosthetic aortic valves. Ultimately, this framework could be extended to other BHVs and improve patient care
Deep Generative Models that Solve PDEs: Distributed Computing for Training Large Data-Free Models
Recent progress in scientific machine learning (SciML) has opened up the
possibility of training novel neural network architectures that solve complex
partial differential equations (PDEs). Several (nearly data free) approaches
have been recently reported that successfully solve PDEs, with examples
including deep feed forward networks, generative networks, and deep
encoder-decoder networks. However, practical adoption of these approaches is
limited by the difficulty in training these models, especially to make
predictions at large output resolutions (). Here we
report on a software framework for data parallel distributed deep learning that
resolves the twin challenges of training these large SciML models - training in
reasonable time as well as distributing the storage requirements. Our framework
provides several out of the box functionality including (a) loss integrity
independent of number of processes, (b) synchronized batch normalization, and
(c) distributed higher-order optimization methods. We show excellent
scalability of this framework on both cloud as well as HPC clusters, and report
on the interplay between bandwidth, network topology and bare metal vs cloud.
We deploy this approach to train generative models of sizes hitherto not
possible, showing that neural PDE solvers can be viably trained for practical
applications. We also demonstrate that distributed higher-order optimization
methods are faster than stochastic gradient-based methods and
provide minimal convergence drift with higher batch-size.Comment: 10 pages, 18 figure
Interpretable deep learning for guided microstructure-property explorations in photovoltaics
The microstructure determines the photovoltaic performance of a thin film organic semiconductor film. The relationship between microstructure and performance is usually highly non-linear and expensive to evaluate, thus making microstructure optimization challenging. Here, we show a data-driven approach for mapping the microstructure to photovoltaic performance using deep convolutional neural networks. We characterize this approach in terms of two critical metrics, its generalizability (has it learnt a reasonable map?), and its intepretability (can it produce meaningful microstructure characteristics that influence its prediction?). A surrogate model that exhibits these two features of generalizability and intepretability is particularly useful for subsequent design exploration. We illustrate this by using the surrogate model for both manual exploration (that verifies known domain insight) as well as automated microstructure optimization. We envision such approaches to be widely applicable to a wide variety of microstructure-sensitive design problems
Interpretable deep learning for guided microstructure-property explorations in photovoltaics
The microstructure determines the photovoltaic performance of a thin film organic semiconductor film. The relationship between microstructure and performance is usually highly non-linear and expensive to evaluate, thus making microstructure optimization challenging. Here, we show a data-driven approach for mapping the microstructure to photovoltaic performance using deep convolutional neural networks. We characterize this approach in terms of two critical metrics, its generalizability (has it learnt a reasonable map?), and its intepretability (can it produce meaningful microstructure characteristics that influence its prediction?). A surrogate model that exhibits these two features of generalizability and intepretability is particularly useful for subsequent design exploration. We illustrate this by using the surrogate model for both manual exploration (that verifies known domain insight) as well as automated microstructure optimization. We envision such approaches to be widely applicable to a wide variety of microstructure-sensitive design problems
Physics-Guided Deep Learning for Dynamical Systems: A survey
Modeling complex physical dynamics is a fundamental task in science and
engineering. Traditional physics-based models are interpretable but rely on
rigid assumptions. And the direct numerical approximation is usually
computationally intensive, requiring significant computational resources and
expertise. While deep learning (DL) provides novel alternatives for efficiently
recognizing complex patterns and emulating nonlinear dynamics, it does not
necessarily obey the governing laws of physical systems, nor do they generalize
well across different systems. Thus, the study of physics-guided DL emerged and
has gained great progress. It aims to take the best from both physics-based
modeling and state-of-the-art DL models to better solve scientific problems. In
this paper, we provide a structured overview of existing methodologies of
integrating prior physical knowledge or physics-based modeling into DL and
discuss the emerging opportunities
Encoding Invariances in Deep Generative Models
Reliable training of generative adversarial networks (GANs) typically require massive datasets in order to model complicated distributions. However, in several applications, training samples obey invariances that are \textit{a priori} known; for example, in complex physics simulations, the training data obey universal laws encoded as well-defined mathematical equations. In this paper, we propose a new generative modeling approach, InvNet, that can efficiently model data spaces with known invariances. We devise an adversarial training algorithm to encode them into data distribution. We validate our framework in three experimental settings: generating images with fixed motifs; solving nonlinear partial differential equations (PDEs); and reconstructing two-phase microstructures with desired statistical properties. We complement our experiments with several theoretical results.This is a pre-print of the article Shah, Viraj, Ameya Joshi, Sambuddha Ghosal, Balaji Pokuri, Soumik Sarkar, Baskar Ganapathysubramanian, and Chinmay Hegde. "Encoding Invariances in Deep Generative Models." arXiv preprint arXiv:1906.01626 (2019). Posted with permission.</p