# Subspace-based dimension reduction for chemical kinetics applications with epistemic uncertainty Source: [Subspace-based dimension reduction for chemical kinetics applications with epistemic uncertainty]() Collection index: [llms.txt]() Data updated: 2025-10-24T23:26:01.670Z Authors: M. Vohra, A. Alexanderian, H. Guy, S. Mahadevan Published: 2018-10-01T20:05:51.000Z ## Abstract We focus on an efficient approach for quantification of uncertainty in complex chemical reaction networks with a large number of uncertain parameters. Parameter dimension reduction is accomplished by computing an active subspace that predominantly captures the variability in the quantity of interest (QoI). In the present work, we compute the active subspace for a H2/O2 mechanism that involves 19 chemical reactions, using an efficient iterative strategy. The active subspace is first computed for a 19-parameter problem wherein only the uncertainty in the pre-exponents of the individual reaction rates is considered. This is followed by the analysis of a 33-dimensional case wherein the activation energies are also considered uncertain. In both cases, a 1-dimensional active subspace is identified, which indicates enormous potential for efficient statistical analysis of complex chemical systems. In addition, we explore links between active subspaces and global sensitivity analysis, and exploit these links for identification of key contributors to the variability in the model response. ## Recorded benchmark results A research result applies to its stated dataset, split, metric and evaluation configuration. Compare like-for-like settings, preserve the metric's unit and direction, and distinguish paper-reported results from independent reproduction. The best result recorded here is not a claim of exhaustive, current global coverage. ## Original sources and implementation [Original paper]() [PDF]()