32 research outputs found
Sensitivity analysis of expensive black-box systems using metamodeling
Simulations are becoming ever more common as a tool for designing complex
products. Sensitivity analysis techniques can be applied to these simulations
to gain insight, or to reduce the complexity of the problem at hand. However,
these simulators are often expensive to evaluate and sensitivity analysis
typically requires a large amount of evaluations. Metamodeling has been
successfully applied in the past to reduce the amount of required evaluations
for design tasks such as optimization and design space exploration. In this
paper, we propose a novel sensitivity analysis algorithm for variance and
derivative based indices using sequential sampling and metamodeling. Several
stopping criteria are proposed and investigated to keep the total number of
evaluations minimal. The results show that both variance and derivative based
techniques can be accurately computed with a minimal amount of evaluations
using fast metamodels and FLOLA-Voronoi or density sequential sampling
algorithms.Comment: proceedings of winter simulation conference 201
Active learning for approximation of expensive functions with normal distributed output uncertainty
When approximating a black-box function, sampling with active learning
focussing on regions with non-linear responses tends to improve accuracy. We
present the FLOLA-Voronoi method introduced previously for deterministic
responses, and theoretically derive the impact of output uncertainty. The
algorithm automatically puts more emphasis on exploration to provide more
information to the models
Multi-objective variable subset selection using heterogeneous surrogate modeling and sequential design
GPflowOpt: A Bayesian Optimization Library using TensorFlow
A novel Python framework for Bayesian optimization known as GPflowOpt is
introduced. The package is based on the popular GPflow library for Gaussian
processes, leveraging the benefits of TensorFlow including automatic
differentiation, parallelization and GPU computations for Bayesian
optimization. Design goals focus on a framework that is easy to extend with
custom acquisition functions and models. The framework is thoroughly tested and
well documented, and provides scalability. The current released version of
GPflowOpt includes some standard single-objective acquisition functions, the
state-of-the-art max-value entropy search, as well as a Bayesian
multi-objective approach. Finally, it permits easy use of custom modeling
strategies implemented in GPflow