30 citations · 107 across the 15 of their papers we have counts for
18 papers
Characterizing variation bounding in discrete-time Hankel operators
Zijian Liu, Tom Ashani, Christian Grussler
We investigate the -variation bounding property of the discrete-time Hankel operator, i.e., its invariance under the set of signals with a variation (number of sign changes) of…
Model-Free Disturbance Observer with Online Modification: Listening to MFDOOM
Nadav Barak, Christian Grussler
Data-Enabled Predictive Control (DeePC) has recently emerged as a framework for controlling unknown systems from data. However, its performance relies on the relevance of the colle…
Inversion of the Multiplicative Matrix Compound Operator
Debojyoti Dey, Ron Ofir, Christian Grussler
We study the problem of determining a matrix whose th multiplicative compound, with , is a prescribed matrix . The cardinality of the set of matrices whose th multi…
Efficient -Sign Consistency Verification of Hankel Matrices via Schur Polynomials
Christian Grussler, Tobias Damm
We consider the problem of certifying (strict) -sign consistency of a matrix, that is, whether all of its -th order minors share the same (strict) sign. Although this problem…
Discrete-Time Periodic Monotonicity Preserving Systems
Christian Grussler
Two nested classes of discrete-time linear time-invariant systems, which differ by the set of periodic signals that they leave invariant, are studied. The first class preserves the…
On System Operators with Variation Bounding Properties
Christian Grussler, Chaim Roth, Kang Tong
The property of linear discrete-time time-invariant system operators mapping inputs with at most sign changes to outputs with at most sign changes is investigated. We s…
Affine-Invariant Midrange Statistics
Cyrus Mostajeran, Christian Grussler, Rodolphe Sepulchre
We formulate and discuss the affine-invariant matrix midrange problem on the cone of positive definite Hermitian matrices , which is based on the Thompso…
Internally Hankel -positive systems
Christian Grussler, Thiago B. Burghi, Somayeh Sojoudi
The classes of externally Hankel -positive LTI systems and autonomous -positive systems have recently been defined, and their properties and applications began to be explored…
On the Similarity to Nonnegative and Metzler Hessenberg Forms
Christian Grussler, Anders Rantzer
We address the issue of establishing standard forms for nonnegative and Metzler matrices by considering their similarity to nonnegative and Metzler Hessenberg matrices. It is shown…
Balanced truncation of -positive systems
Christian Grussler, Tobias Damm, Rodolphe Sepulchre
This paper considers balanced truncation of discrete-time Hankel -positive systems, characterized by Hankel matrices whose minors up to order are nonnegative. Our main resul…
Variation diminishing linear time-invariant systems
Christian Grussler, Rodolphe Sepulchre
This paper studies the variation diminishing property of -positive linear time-invariant (LTI) systems, which map inputs with sign changes to outputs with at most the same…
Geometric Matrix Midranges
Cyrus Mostajeran, Christian Grussler, Rodolphe Sepulchre
We define geometric matrix midranges for positive definite Hermitian matrices and study the midrange problem from a number of perspectives. Special attention is given to the midran…
On second-order cone positive systems
Christian Grussler, Anders Rantzer
Internal positivity offers a computationally cheap certificate for external (input-output) positivity of a linear time-invariant system. However, the drawback with this certificate…
Strongly unimodal systems
Christian Grussler, Rodolphe Sepulchre
We investigate the property for an input-output system to map unimodal inputs to unimodal outputs. As a first step, we analyse this property for linear time-invariant (LTI) systems…
Efficient Proximal Mapping Computation for Unitarily Invariant Low-Rank Inducing Norms
Christian Grussler, Pontus Giselsson
Low-rank inducing unitarily invariant norms have been introduced to convexify problems with low-rank/sparsity constraint. They are the convex envelope of a unitary invariant norm a…
Local Convergence of Proximal Splitting Methods for Rank Constrained Problems
Christian Grussler, Pontus Giselsson
We analyze the local convergence of proximal splitting algorithms to solve optimization problems that are convex besides a rank constraint. For this, we show conditions under which…
Low-Rank Inducing Norms with Optimality Interpretations
Christian Grussler, Pontus Giselsson
Optimization problems with rank constraints appear in many diverse fields such as control, machine learning and image analysis. Since the rank constraint is non-convex, these probl…
Low-rank Optimization with Convex Constraints
Christian Grussler, Anders Rantzer, Pontus Giselsson
The problem of low-rank approximation with convex constraints, which appears in data analysis, system identification, model order reduction, low-order controller design and low-com…