Publications (54)
Neurofeedback Tunes Scale-Free Dynamics in Spontaneous Brain Activity
Tomas Ros, Paul Frewen, Jean Theberge +6
Brain oscillations exhibit long-range temporal correlations (LRTCs), which reflect the regularity of their fluctuations: low values representing more random (decorrelated) while hi…
Workspace Registration and Collision Detection for Industrial Robotics Applications
Klaus Zauner, Josef El Dib, Hubert Gattringer +1
Motion planning for robotic manipulators relies on precise knowledge of the environment in order to be able to define restricted areas and to take collision objects into account. T…
Product Of Exponentials (POE) Splines on Lie-Groups: Limitations, Extensions, and Application to SO(3) and SE(3)
Andreas Mueller
Existing methods for constructing splines and Bezier curves on a Lie group G involve repeated products of exponentials deduced from local geodesics, w.r.t. a Riemannian metric, or…
Geometric Robot Calibration Using a Calibration Plate
Bernhard Rameder, Hubert Gattringer, Andreas Mueller
In this paper a new method for geometric robot calibration is introduced, which uses a calibration plate with precisely known distances between its measuring points. The relative m…
Wireless 6G Connectivity for Massive Number of Devices and Critical Services
Anders E. Kalør, Giuseppe Durisi, Sinem Coleri +4
Compared to the generations up to 4G, whose main focus was on broadband and coverage aspects, 5G has expanded the scope of wireless cellular systems towards embracing two new types…
Is there an optimal choice of configuration space for Lie group integration schemes applied to constrained MBS?
Andreas Mueller, Zdravko Terze
Recently various numerical integration schemes have been proposed for numerically simulating the dynamics of constrained multibody systems (MBS) operating. These integration scheme…
Nexus: Inferring Join Graphs from Metadata Alone via Iterative Low-Rank Matrix Completion
Tianji Cong, Yuanyuan Tian, Andreas Mueller +5
Automatically inferring join relationships is a critical task for effective data discovery, integration, querying and reuse. However, accurately and efficiently identifying these r…
The significance of the configuration space Lie group for the constraint satisfaction in numerical time integration of multibody systems
Andreas Mueller, Zdravko Terze
The dynamics simulation of multibody systems (MBS) using spatial velocities (non-holonomic velocities) requires time integration of the dynamics equations together with the kinemat…
Towards Building Autonomous Data Services on Azure
Yiwen Zhu, Yuanyuan Tian, Joyce Cahoon +35
Modern cloud has turned data services into easily accessible commodities. With just a few clicks, users are now able to access a catalog of data processing systems for a wide range…
API design for machine learning software: experiences from the scikit-learn project
Lars Buitinck, Gilles Louppe, Mathieu Blondel +12
Scikit-learn is an increasingly popular machine learning li- brary. Written in Python, it is designed to be simple and efficient, accessible to non-experts, and reusable in various…
GAMformer: Bridging Tabular Foundation Models and Interpretable Machine Learning
Andreas Mueller, Julien Siems, Harsha Nori +4
While interpretability is crucial for machine learning applications in safety-critical domains and for regulatory compliance, existing tabular foundation models like TabPFN lack tr…
Altered oscillatory brain networks during emotional face processing in ADHD: an eLORETA and functional ICA study
Saghar Vosough, Gian Candrian, Johannes Kasper +4
Attention-deficit/hyperactivity disorder (ADHD) is characterized by executive dysfunction and difficulties in processing emotional facial expressions, yet the large-scale neural dy…
Robot Path and Trajectory Planning Considering a Spatially Fixed TCP
Bernhard Rameder, Hubert Gattringer, Andreas Mueller +1
This paper presents a method for planning a trajectory in workspace coordinates using a spatially fixed tool center point (TCP), while taking into account the processing path on a…
Cosmology and general relativity (GR) in upper secondary school through new targeted teaching materials: a study on student learning and motivation
Alice Gasparini, Andreas Mueller, Florian Stern +1
Cosmology and GR remain largely inaccessible to high-school teaching due to the advanced prerequisites to master these topics. Integrating them into upper secondary teaching is a s…
Open Challenges in Time Series Anomaly Detection: An Industry Perspective
Andreas Mueller
Current research in time-series anomaly detection is using definitions that miss critical aspects of how anomaly detection is commonly used in practice. We list several areas that…
Singularity-Free Lie Group Integration and Geometrically Consistent Evaluation of Multibody System Models Described in Terms of Standard Absolute Coordinates
Andreas Mueller
A classical approach to the multibody systems (MBS) modeling is to use absolute coordinates, i.e., a set of (possibly redundant) coordinates that describe the absolute position and…
Screw and Lie Group Theory in Multibody Kinematics -- Motion Representation and Recursive Kinematics of Tree-Topology Systems
Andreas Mueller
After three decades of computational multibody system (MBS) dynamics, current research is centered at the development of compact and user friendly yet computationally efficient for…
Screw and Lie Group Theory in Multibody Dynamics -- Recursive Algorithms and Equations of Motion of Tree-Topology Systems
Andreas Mueller
Screw and Lie group theory allows for user-friendly modeling of multibody systems (MBS) while at the same they give rise to computationally efficient recursive algorithms. The inhe…
Closed Form Time Derivatives of the Equations of Motion of Rigid Body Systems
Andreas Mueller, Shivesh Kumar
Derivatives of equations of motion(EOM) describing the dynamics of rigid body systems are becoming increasingly relevant for the robotics community and find many applications in de…
Towards Continuous Time Finite Horizon LQR Control in SE(3)
Shivesh Kumar, Andreas Mueller, Patrick Wensing +1
The control of free-floating robots requires dealing with several challenges. The motion of such robots evolves on a continuous manifold described by the Special Euclidean Group of…
Geometric Interpolation of Rigid Body Motions
Andreas Mueller
The problem of interpolating a rigid body motion is to find a spatial trajectory between a prescribed initial and terminal pose. Two variants of this interpolation problem are addr…
Experimental Evidence of Black Holes
Andreas Mueller
Classical black holes are solutions of the field equations of General Relativity. Many astronomical observations suggest that black holes really exist in nature. However, an unambi…
Dynamics of Parallel Manipulators with Hybrid Complex Limbs -- Modular Modeling and Parallel Computing
Andreas Mueller
Parallel manipulators, also called parallel kinematics machines (PKM), enable robotic solutions for highly dynamic handling and machining applications. The safe and accurate design…
A Parameter-Linear Formulation of the Optimal Path Following Problem for Robotic Manipulator
Tobias Marauli, Hubert Gattringer, Andreas Mueller
In this paper the computational challenges of time-optimal path following are addressed. The standard approach is to minimize the travel time, which inevitably leads to singulariti…
Optimizing open-domain question answering with graph-based retrieval augmented generation
Joyce Cahoon, Prerna Singh, Nick Litombe +6
In this work, we benchmark various graph-based retrieval-augmented generation (RAG) systems across a broad spectrum of query types, including OLTP-style (fact-based) and OLAP-style…
Network Slicing for Ultra-Reliable Low Latency Communication in Industry 4.0 Scenarios
Anders Ellersgaard Kalør, René Guillaume, Jimmy Jessen Nielsen +2
An important novelty of 5G is its role in transforming the industrial production into Industry 4.0. Specifically, Ultra-Reliable Low Latency Communications (URLLC) will, in many ca…
Analysis of Deep-Learning Methods in an ISO/TS 15066-Compliant Human-Robot Safety Framework
David Bricher, Andreas Mueller
Over the last years collaborative robots have gained great success in manufacturing applications where human and robot work together in close proximity. However, current ISO/TS-150…
An Overview of Formulae for the Higher-Order Kinematics of Lower-Pair Chains with Applications in Robotics and Mechanism Theory
Andreas Mueller
The motions of mechanisms can be described in terms of screw coordinates by means of an exponential mapping. The product of exponentials (POE) describes the configuration of a chai…
Evolution of supermassive black holes
Andreas Mueller, Guenther Hasinger
The cosmological evolution of supermassive black holes (SMBHs) seems to be intimately linked to their host galaxies. Active galactic nuclei (AGN) can be probed by deep X-ray survey…
On the Signatures of Gravitational Redshift: The Onset of Relativistic Emission Lines
Andreas Mueller, Margrethe Wold
Aims. We quantify the effect of gravitational redshift on emission lines to explore the transition region from the Newtonian to the Einsteinian regime. With the emitting region clo…
Time-Optimal Transport of Loosely Placed Liquid Filled Cups along Prescribed Paths
Klaus Zauner, Hubert Gattringer, Andreas Mueller
Handling loosely placed objects with robotic manipulators is a difficult task from the point of view of trajectory planning and control. This becomes even more challenging when the…
On the Performance of Linear Adaptive Filters driven by the Ergodic Chaotic Logistic Map
Andreas Mueller
Chaotic dynamical systems are increasingly considered for use in coding and transmission systems. This stems from their parameter sensitivity and spectral characteristics. The latt…
A Recursive Lie-Group Formulation for the Second-Order Time Derivatives of the Inverse Dynamics of parallel Kinematic Manipulators
Andreas Mueller, Shivesh Kumar, Thomas Kordik
Series elastic actuators (SEA) were introduced for serial robotic arms. Their model-based trajectory tracking control requires the second time derivatives of the inverse dynamics s…
Hamel's Equations and Geometric Mechanics of Constrained and Floating Multibody and Space Systems
Andreas Mueller
Modern geometric approaches to analytical mechanics rest on a bundle structure of the configuration space. The connection on this bundle allows for an intrinsic splitting of the re…
Wohlhart's Three-Loop Mechanism: An Overconstrained and Shaky Linkage
Andreas Mueller
This paper revisits a three-loop spatial linkage that was proposed in an ARK 2004 paper by Karl Wohlhart (as extension of a two-loop linkage proposed by Eddie Baker in 1980) and la…
Review of the Exponential and Cayley Map on SE(3) as relevant for Lie Group Integration of the Generalized Poisson Equation and Flexible Multibody Systems
Andreas Mueller
The exponential and Cayley map on SE(3) are the prevailing coordinate maps used in Lie group integration schemes for rigid body and flexible body systems. Such geometric integrator…
Simultaneous Stiffness and Trajectory Optimization for Energy Minimization of Pick-and-Place Tasks of SEA-Actuated Parallel Kinematic Manipulators
Thomas Kordik, Hubert Gattringer, Andreas Mueller
A major field of industrial robot applications deals with repetitive tasks that alternate between operating points. For these so-called pick-and-place operations, parallel kinemati…
Position: A Call to Action for a Human-Centered AutoML Paradigm
Marius Lindauer, Florian Karl, Anne Klier +6
Automated machine learning (AutoML) was formed around the fundamental objectives of automatically and efficiently configuring machine learning (ML) workflows, aiding the research o…
Forward Dynamics of Variable Topology Mechanisms - The Case of Constraint Activation
Andreas Mueller
Many mechanical systems exhibit changes in their kinematic topology altering the mobility. Ideal contact is the best known cause, but also stiction and controlled locking of parts…
An )-Algorithm for the Higher-Order Kinematics and Inverse Dynamics of Serial Manipulators using Spatial Representation of Twists
Andreas Mueller
Optimal control in general, and flatness-based control in particular, of robotic arms necessitate to compute the first and second time derivatives of the joint torques/forces requi…
Deconvolving oscillatory transients with a Kalman filter
Andreas Mueller
This paper describes a method to filter oscillatory transients from measurements of a time series which were at least an order of magnitude larger than the signal to be measured. B…
Analytically Informed Inverse Kinematics Solution at Singularities
Andreas Mueller
Near kinematic singularities of a serial manipulator, the inverse kinematics (IK) problem becomes ill-conditioned, which poses computational problems for the numerical solution. Co…
A Constraint Embedding Approach for Dynamics Modeling of Parallel Kinematic Manipulators with Hybrid Limbs
Andreas Mueller
Parallel kinematic manipulators (PKM) are characterized by closed kinematic loops, due to the parallel arrangement of limbs but also due to the existence of kinematic loops within…
Non-monotonic orbital velocity profiles around rapidly rotating Kerr-(anti-)de Sitter black holes
Andreas Mueller, Bernd Aschenbach
It has been recently demonstrated that the orbital velocity profile around Kerr black holes in the equatorial plane as observed in the locally non-rotating frame exhibits a non-mon…
On the Terminology and Geometric Aspects of Redundant Parallel Manipulators
Andreas Mueller
Parallel kinematics machines (PKM) can exhibit kinematic as well as actuation redundancy. While the meaning of kinematic redundancy has been clarified already for serial manipulato…
Closed Form Relations and Higher-Order Approximations of First and Second Derivatives of the Tangent Operator on SE(3)
Andreas Mueller
The Lie group SE(3) of isometric orientation preserving transformation is used for modeling multibody systems, robots, and Cosserat continua. The use of these models in numerical s…
A Screw Approach to the Approximation of the Local Geometry of the Configuration Space and of the set of Configurations of Certain Rank of Lower Pair Linkages
Andreas Mueller
A motion of a mechanism is a curve in its configuration space (c-space). Singularities of the c-space are kinematic singularities of the mechanism. Any mobility analysis of a parti…
Nth Order Analytical Time Derivatives of Inverse Dynamics in Recursive and Closed Forms
Shivesh Kumar, Andreas Mueller
Derivatives of equations of motion describing the rigid body dynamics are becoming increasingly relevant for the robotics community and find many applications in design and control…
An Automated Tape Laying System Employing a Uniaxial Force Control Device
Bernhard Rameder, Hubert Gattringer, Ronald Naderer +1
This paper deals with the design of a cost effective automated tape laying system (ATL system) with integrated uniaxial force control to ensure the necessary compaction forces as w…
The onset of General Relativity: Gravitationally redshifted emission lines
Andreas Mueller
We study and quantify gravitational redshift by means of relativistic ray tracing simulations of emission lines. The emitter model is based on thin, Keplerian rotating rings in the…
Relativistic emission lines from accreting black holes - The effect of disk truncation on line profiles
Andreas Mueller, Max Camenzind
Relativistic emission lines generated by thin accretion disks around rotating black holes are an important diagnostic tool for testing gravity near the horizon. The iron K-line is…
An approach for combining transparency and motion assistance of a lower body exoskeleton
Jakob Ziegler, Bernhard Rameder, Hubert Gattringer +1
In this paper, an approach for gait assistance with a lower body exoskeleton is described. Two concepts, transparency and motion assistance, are combined. The transparent mode, whe…
Optimal Dimensioning of Elastic-Link Manipulators regarding Lifetime Estimation
Klaus Zauner, Hubert Gattringer, Andreas Mueller
Resourceful operation and design of robots is key for sustainable industrial automation. This will be enabled by lightweight design along with time and energy optimal control of ro…
Identification of Non-Transversal Bifurcations of Linkages
Andreas Mueller, P. C. López Custodio, J. S. Dai
The local analysis is an established approach to the study of singularities and mobility of linkages. Key result of such analyses is a local picture of the finite motion through a…