Search Results for author: Stefan Klus

Found 22 papers, 10 papers with code

Transfer operators on graphs: Spectral clustering and beyond

no code implementations19 May 2023 Stefan Klus, Maia Trower

Graphs and networks play an important role in modeling and analyzing complex interconnected systems such as transportation networks, integrated circuits, power grids, citation graphs, and biological and artificial neural networks.

Clustering Graph Clustering

Koopman-based spectral clustering of directed and time-evolving graphs

no code implementations6 Apr 2022 Stefan Klus, Natasa Djurdjevac Conrad

While spectral clustering algorithms for undirected graphs are well established and have been successfully applied to unsupervised machine learning problems ranging from image segmentation and genome sequencing to signal processing and social network analysis, clustering directed graphs remains notoriously difficult.

Clustering Image Segmentation +1

A Dynamic Mode Decomposition Approach for Decentralized Spectral Clustering of Graphs

no code implementations26 Feb 2022 Hongyu Zhu, Stefan Klus, Tuhin Sahai

Our proposed method uses the existing wave equation clustering algorithm that is based on propagating waves through the graph.

Clustering Graph Clustering

Symmetric and antisymmetric kernels for machine learning problems in quantum physics and chemistry

no code implementations31 Mar 2021 Stefan Klus, Patrick Gelß, Feliks Nüske, Frank Noé

We derive symmetric and antisymmetric kernels by symmetrizing and antisymmetrizing conventional kernels and analyze their properties.

BIG-bench Machine Learning

Data-driven model reduction of agent-based systems using the Koopman generator

1 code implementation14 Dec 2020 Jan-Hendrik Niemann, Stefan Klus, Christof Schütte

The dynamical behavior of social systems can be described by agent-based models.

Feature space approximation for kernel-based supervised learning

1 code implementation25 Nov 2020 Patrick Gelß, Stefan Klus, Ingmar Schuster, Christof Schütte

We propose a method for the approximation of high- or even infinite-dimensional feature vectors, which play an important role in supervised learning.

regression Time Series +1

GraphKKE: Graph Kernel Koopman Embedding for Human Microbiome Analysis

1 code implementation12 Aug 2020 Kateryna Melnyk, Stefan Klus, Grégoire Montavon, Tim Conrad

We demonstrate that our method can capture temporary changes in the time-evolving graph on both created synthetic data and real-world data.

Kernel-based approximation of the Koopman generator and Schrödinger operator

1 code implementation27 May 2020 Stefan Klus, Feliks Nüske, Boumediene Hamzi

Furthermore, we exploit that, under certain conditions, the Schr\"odinger operator can be transformed into a Kolmogorov backward operator corresponding to a drift-diffusion process and vice versa.

Kernel Autocovariance Operators of Stationary Processes: Estimation and Convergence

no code implementations2 Apr 2020 Mattes Mollenhauer, Stefan Klus, Christof Schütte, Péter Koltai

We consider autocovariance operators of a stationary stochastic process on a Polish space that is embedded into a reproducing kernel Hilbert space.

Tensor-based algorithms for image classification

1 code implementation4 Oct 2019 Stefan Klus, Patrick Gelß

The interest in machine learning with tensor networks has been growing rapidly in recent years.

BIG-bench Machine Learning Classification +4

Data-driven approximation of the Koopman generator: Model reduction, system identification, and control

no code implementations23 Sep 2019 Stefan Klus, Feliks Nüske, Sebastian Peitz, Jan-Hendrik Niemann, Cecilia Clementi, Christof Schütte

We derive a data-driven method for the approximation of the Koopman generator called gEDMD, which can be regarded as a straightforward extension of EDMD (extended dynamic mode decomposition).

Model Predictive Control

Tensor-based computation of metastable and coherent sets

1 code implementation12 Aug 2019 Feliks Nüske, Patrick Gelß, Stefan Klus, Cecilia Clementi

Recent years have seen rapid advances in the data-driven analysis of dynamical systems based on Koopman operator theory and related approaches.

Kernel Conditional Density Operators

no code implementations27 May 2019 Ingmar Schuster, Mattes Mollenhauer, Stefan Klus, Krikamol Muandet

The proposed model is based on a novel approach to the reconstruction of probability densities from their kernel mean embeddings by drawing connections to estimation of Radon-Nikodym derivatives in the reproducing kernel Hilbert space (RKHS).

Density Estimation Gaussian Processes

Dimensionality Reduction of Complex Metastable Systems via Kernel Embeddings of Transition Manifolds

1 code implementation18 Apr 2019 Andreas Bittracher, Stefan Klus, Boumediene Hamzi, Péter Koltai, Christof Schütte

We present a novel kernel-based machine learning algorithm for identifying the low-dimensional geometry of the effective dynamics of high-dimensional multiscale stochastic systems.

Dimensionality Reduction

Kernel methods for detecting coherent structures in dynamical data

no code implementations16 Apr 2019 Stefan Klus, Brooke E. Husic, Mattes Mollenhauer, Frank Noé

In particular, we show that kernel canonical correlation analysis (CCA) can be interpreted in terms of kernel transfer operators and that it can be obtained by optimizing the variational approach for Markov processes (VAMP) score.

Dimensionality Reduction

Learning chemical reaction networks from trajectory data

1 code implementation13 Feb 2019 Wei zhang, Stefan Klus, Tim Conrad, Christof Schütte

We develop a data-driven method to learn chemical reaction networks from trajectory data.

Optimization and Control 92C42, 62M86

A kernel-based approach to molecular conformation analysis

no code implementations28 Sep 2018 Stefan Klus, Andreas Bittracher, Ingmar Schuster, Christof Schütte

We present a novel machine learning approach to understanding conformation dynamics of biomolecules.

BIG-bench Machine Learning

Singular Value Decomposition of Operators on Reproducing Kernel Hilbert Spaces

no code implementations24 Jul 2018 Mattes Mollenhauer, Ingmar Schuster, Stefan Klus, Christof Schütte

Reproducing kernel Hilbert spaces (RKHSs) play an important role in many statistics and machine learning applications ranging from support vector machines to Gaussian processes and kernel embeddings of distributions.

Gaussian Processes

Analyzing high-dimensional time-series data using kernel transfer operator eigenfunctions

no code implementations16 May 2018 Stefan Klus, Sebastian Peitz, Ingmar Schuster

Kernel transfer operators, which can be regarded as approximations of transfer operators such as the Perron-Frobenius or Koopman operator in reproducing kernel Hilbert spaces, are defined in terms of covariance and cross-covariance operators and have been shown to be closely related to the conditional mean embedding framework developed by the machine learning community.

Time Series Time Series Analysis +1

Eigendecompositions of Transfer Operators in Reproducing Kernel Hilbert Spaces

1 code implementation5 Dec 2017 Stefan Klus, Ingmar Schuster, Krikamol Muandet

Transfer operators such as the Perron--Frobenius or Koopman operator play an important role in the global analysis of complex dynamical systems.

Variational Koopman models: slow collective variables and molecular kinetics from short off-equilibrium simulations

no code implementations20 Oct 2016 Hao Wu, Feliks Nüske, Fabian Paul, Stefan Klus, Peter Koltai, Frank Noé

Recently, a powerful generalization of MSMs has been introduced, the variational approach (VA) of molecular kinetics and its special case the time-lagged independent component analysis (TICA), which allow us to approximate slow collective variables and molecular kinetics by linear combinations of smooth basis functions or order parameters.

Clustering Dimensionality Reduction

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