23 papers · ranked by Valyu relevance
Peter Giesl, Sigurður Hafstein, Christoph Kawan
Contraction analysis considers the distance between two adjacent trajectories. If this distance is contracting, then trajectories have the same long-term behavior. The main advantage of this analysis is that it is independent of the solutions under consideration. Using an appropriate metric, with respect to which the…
Fulvio Forni, Rodolphe Sepulchre
—Lyapunov's second theorem is an essential tool for stability analysis of differential equations. The paper provides an analog theorem for incremental stability analysis by lifting the Lyapunov function to the tangent bundle. The Lyapunov function endows the state-space with a Finsler structure. Incremental stability…
Hung D. Nguyen, Thanh Long Vu, Jean-Jacques Slotine, Konstantin Turitsyn
'Konstantin Turitsyn'] This paper studies the contraction properties of nonlinear differential-algebraic equation (DAE) systems. Specifically we develop scalable techniques for constructing the attraction regions associated with a particular stable equilibrium, by establishing the relation between the contraction rates…
L. Sala, B.J. van Meer, L.G.J. Tertoolen, J. Bakkers + 22 more
Contraction of muscle reflects its physiological state. Methods to quantify contraction are often complex, expensive and tailored to specific models or recording conditions, or require specialist knowledge for data extraction. Here we describe an automated, open-source software tool (MUSCLEMOTION) adaptable for use…
Hao Yin, Bayu Jayawardhana, Stephan Trenn
This paper introduce the notion of output contraction that expands the contraction notion to the time-varying nonlinear systems with output. It pertains to the systems' property that any pair of outputs from the system converge to each other exponentially. This concept exhibits a more expansive nature when contrasted…
Leo Kozachkov, Mikael Lundqvist, Jean-Jacques Slotine, Earl K. Miller
The brain consists of many interconnected networks with time-varying, partially autonomous activity. There are multiple sources of noise and variation yet activity has to eventually converge to a stable, reproducible state (or sequence of states) for its computations to make sense. We approached this problem from a…
Wim JEP Lammers, Leo K Cheng
Background Spatio-temporal (ST) maps provide a method for visualizing a temporally evolving and spatially varying field, which can also be used in the analysis of gastrointestinal motility. However, it is not always clear what the underlying contractions are that are represented in ST maps and whether some types of…
Leo Kozachkov, Mikael Lundqvist, Jean-Jacques Slotine, Earl K. Miller
The brain consists of many interconnected networks with time-varying activity. There are multiple sources of noise and variation yet activity has to eventually converge to a stable state for its computations to make sense. We approached this from a control-theory perspective by applying contraction analysis to…
Sridhar P. Arjunan, Dinesh K. Kumar, Ganesh Naik
The relationship between force of muscle contraction and muscle fatigue with six different features of surface electromyogram (sEMG) was determined by conducting experiments on thirty-five volunteers. The participants performed isometric contractions at 50%, 75%, and 100% of their maximum voluntary contraction (MVC).…
Hannah D. Carey, Friedl De Groote, Andrew Sawers
Co-contraction—the simultaneous activation of opposing muscles—influences movement efficiency, joint stability, and motor learning. While consensus exists for EMG acquisition and processing, comparable guidance for quantifying co-contraction is lacking. This study evaluated the behavior and interrelationships of six…
Jack D. Evans, Johannes P. Dürholt, Stefan Kaskel, Rochus Schmid
Most conventional materials display expansion upon heating, so there is considerable interest in identifying materials that display the opposite behavior, negative thermal expansion (NTE). In the current study, seven mesoporous metal-organic frameworks (MOFs) of varying topology and composition, which exhibit…
Hannah D. Carey, Friedl De Groote, Andrew Sawers, Andrea Tigrini
Co-contraction-the simultaneous activation of opposing muscles-influences movement efficiency, joint stability, and motor learning. While consensus exists for EMG acquisition and processing, comparable guidance for quantifying co-contraction is lacking. This study evaluated the behavior and interrelationships of six…
Paolo Tecchio, Brent J. Raiteri, Daniel Hahn
Whether eccentric exercise involves active fascicle stretch is unclear due to muscle-tendon unit (MTU) series elasticity. Therefore, this study investigated the impact of changing the activation timing and level (i.e., pre-activation) on muscle fascicle kinematics and kinetics of the human tibialis anterior during…
Julian Colard, Julien Duclay, Yohan Betus, Thomas Cattagni + 1 more
It is well documented that, in soleus, motoneuron output and the effectiveness of activated Ia afferents to discharge α-motoneurons both decrease during eccentric contractions. Evidence suggests that these regulations can be explained by (1) recurrent inhibition and (2) greater post-activation depression by primary…
Emmet J. Mc Dermott, Thomas G. Balshaw, Katherine Brooke-Wavell, Thomas M. Maden-Wilkinson + 1 more
Purpose Neuromuscular power is critical for healthy ageing. Conventional older adult resistance training (RT) guidelines typically recommend lifting slowly (2-s; CONV), whereas fast/explosive contractions performed either non-ballistically (FAST-NB) or ballistically (FAST-B, attempting to throw the load) may involve…
Elizabeth Saunders, Brian C. Clark, Leatha A. Clark, Dustin R. Grooms
'Dustin R. Grooms'] Title: Abstract The purpose of this study was to quantify head motion between isometric erector spinae (ES) contraction strategies, paradigms, and intensities in the development of a neuroimaging protocol for the study of neural activity associated with trunk motor control in individuals with low…
Francesco Di Nardo, Martina Morano, Annachiara Strazza, Sandro Fioretti + 1 more
'Sandro Fioretti' 'Enrico G. Caiani'] Background: Muscle co-contraction plays a significant role in motion control. Available detection methods typically only provide information in the time domain. The current investigation proposed a novel approach for muscle co-contraction detection in the time-frequency domain…
Michael Skovdal Rathleff, Kristian Thorborg, Thomas Bandholm, François Hug
'François Hug'] Background Total, single repetition and contraction-phase specific (concentric and eccentric) time-under-tension (TUT) are important exercise-descriptors, as they are linked to the physiological and clinical response in exercise and rehabilitation. Objective To investigate the validity and reliability…
Tobias Brevé, Huanhuan Liu, Antonia Denkova, Rienk Eelkema
We describe the gamma radiation induced crosslinking of alkyne-modified dextran polymer gels. Crosslinking of the alkyne moieties leads to gel contraction and fusion with other gel objects, and can be used for controlled release.
Alan Khoja, Martin Kölbl, Stefan Leue, Rüdiger Wilhelmi
We describe a method and tool called ContractCheck [9] that allows for the consistency analysis of legal contracts, in particular Sales Purchase Agreements (SPAs). The analysis relies on an encoding of the premises for the execution of the clauses of an SPA as well as the proposed consistency constraints using…
Authors not listed
Ring contraction reactions facilitate easy access to carbo- and heterocyclic scaffolds from readily available precursors and have therefore enjoyed great popularity as a strategy in organic synthesis for a long time. By repurposing commercial alcohol dehydrogenases as borrowing hydrogen biocatalysts, we were able to…
Milena A. dos Santos, Hélio V. Cabral, J Greig Inglis, Caterina Cosentino + 3 more
This study investigated how altering the length of one muscle influences motor unit discharge behavior of its synergists. Eighteen participants performed isometric knee extensions at 10% and 30% of maximal voluntary contraction (MVC) with the hip joint at 90° (shortened rectus femoris, RF) and 180° (lengthened RF).…
David R. Ferreira, Alexandra Mendes, João F. Ferreira
Formal contracts and assertions are effective methods to enhance software quality by enforcing preconditions, postconditions, and invariants. Previous research has demonstrated the value of contracts in traditional software development contexts. However, the adoption and impact of contracts in the context of mobile…