92 research outputs found
A weakness measure for GR(1) formulae
In spite of the theoretical and algorithmic developments for system synthesis in recent years, little effort has been dedicated to quantifying the quality of the specifications used for synthesis. When dealing with unrealizable specifications, finding the weakest environment assumptions that would ensure realizability is typically a desirable property; in such context the weakness of the assumptions is a major quality parameter. The question of whether one assumption is weaker than another is commonly interpreted using implication or, equivalently, language inclusion. However, this interpretation does not provide any further insight into the weakness of assumptions when implication does not hold. To our knowledge, the only measure that is capable of comparing two formulae in this case is entropy, but even it fails to provide a sufficiently refined notion of weakness in case of GR(1) formulae, a subset of linear temporal logic formulae which is of particular interest in controller synthesis. In this paper we propose a more refined measure of weakness based on the Hausdorff dimension, a concept that captures the notion of size of the omega-language satisfying a linear temporal logic formula. We identify the conditions under which this measure is guaranteed to distinguish between weaker and stronger GR(1) formulae. We evaluate our proposed weakness measure in the context of computing GR(1) assumptions refinements
Novel Coronin7 interactions with Cdc42 and N-WASP regulate actin organization and Golgi morphology
YesThe contribution of the actin cytoskeleton to the unique architecture of the Golgi complex is manifold.
An important player in this process is Coronin7 (CRN7), a Golgi-resident protein that stabilizes F-actin
assembly at the trans-Golgi network (TGN) thereby facilitating anterograde trafficking. Here, we
establish that CRN7-mediated association of F-actin with the Golgi apparatus is distinctly modulated
via the small Rho GTPase Cdc42 and N-WASP. We identify N-WASP as a novel interaction partner of
CRN7 and demonstrate that CRN7 restricts spurious F-actin reorganizations by repressing N-WASP
âhyperactivityâ upon constitutive Cdc42 activation. Loss of CRN7 leads to increased cellular F-actin
content and causes a concomitant disruption of the Golgi structure. CRN7 harbours a Cdc42- and
Rac-interactive binding (CRIB) motif in its tandem ÎČ-propellers and binds selectively to GDP-bound
Cdc42N17 mutant. We speculate that CRN7 can act as a cofactor for active Cdc42 generation. Mutation
of CRIB motif residues that abrogate Cdc42 binding to CRN7 also fail to rescue the cellular defects in
fibroblasts derived from CRN7 KO mice. Cdc42N17 overexpression partially rescued the KO phenotypes
whereas N-WASP overexpression failed to do so. We conclude that CRN7 spatiotemporally influences
F-actin organization and Golgi integrity in a Cdc42- and N-WASP-dependent manner.This work was supported by SFB 670 and DFG NO 113/22. K.B. was supported by a fellowship from the NRW International Graduate School âFrom Embryo to Old Age: the Cell Biology and Genetics of Health and Diseaseâ (IGSDHD), Cologne
ARHGEF15 overexpression worsens the prognosis in patients with pancreatic ductal adenocarcinoma through enhancing the motility and proliferative activity of the cancer cells
EURECâŽA
The science guiding the EURECâŽA campaign and its measurements is presented. EURECâŽA comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic â eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EURECâŽA marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200âkm) and larger (500âkm) scales, roughly 400âh of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10â000 profiles), lower atmosphere (continuous profiling), and along the airâsea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EURECâŽA explored â from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation â are presented along with an overview of EURECâŽA's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement
EURECâŽA
The science guiding the EURECâŽA campaign and its measurements is presented. EURECâŽA comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic â eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EURECâŽA marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200âkm) and larger (500âkm) scales, roughly 400âh of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10â000 profiles), lower atmosphere (continuous profiling), and along the airâsea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EURECâŽA explored â from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation â are presented along with an overview of EURECâŽA's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement
Contribution aux tests de vacuité pour le model checking explicite
The automata-theoretic approach to linear time model-checking is a standard technique for formal verification of concurrent systems. The system and the property to check are modeled with omega-automata that recognizes infinite words. Operations overs these automata (synchronized product and emptiness checks) allows to determine whether the system satisfies the property or not. In this thesis we focus on a particular type of omega-automata that enable a concise representation of weak fairness properties: transitions-based generalized BĂŒchi automata (TGBA). First we outline existing verification algorithms, and we propose new efficient algorithms for strong automata. In a second step, the analysis of the strongly connected components of the property automaton led us to develop a decomposition of this automata. This decomposition focuses on multi-strength property automata and allows a natural parallelization for already existing model-checkers. Finally, we proposed, for the first time, new parallel emptiness checks for generalized BĂŒchi automata. Moreover, all these emptiness checks are lock-free, unlike those of the state-of-the-art. All these techniques have been implemented and then evaluated on a large benchmark.L'approche automate pour le model checking de propriĂ©tĂ©s temporelles Ă temps linĂ©aire est une technique classique de vĂ©rification formelle de systĂšmes concurrents. Un systĂšme, ainsi qu'une propriĂ©tĂ© qu'on souhaite y vĂ©rifier, sont modĂ©lisĂ©s sous forme dâomega-automates reconnaissant des mots infinis. Des manipulations de ces automates (produit synchronisĂ© et test de vacuitĂ©) permettent d'Ă©tablir si le systĂšme vĂ©rifie la propriĂ©tĂ© ou non. Dans cette thĂšse nous nous focalisons sur un type particulier d'omega-automates qui permettent une reprĂ©sentation concise des propriĂ©tĂ©s d'Ă©quitĂ© faible: les automates de BĂŒchi gĂ©nĂ©ralisĂ©s basĂ©s sur les transitions (TGBA ou Transition-based Generalized BĂŒchi Automata). Dans un premier temps, nous brossons un aperçu des algorithmes de vĂ©rification existant et nous en proposons de nouveaux traitant efficacement les automates gĂ©nĂ©ralisĂ©s forts. Dans un second temps, l'analyse des composantes fortement connexes de l'automate de la propriĂ©tĂ© nous a conduit Ă Ă©laborer une dĂ©composition de cet automate. Cette dĂ©composition se focalise sur les automates multi-forces et permet une parallĂ©lisation naturelle des model-checkers. Enfin, nous avons proposĂ© les premiers tests de vacuitĂ© parallĂšles pour les automates gĂ©nĂ©ralisĂ©s. De plus, tous ces tests sont lock-free Ă la diffĂ©rence de ceux de lâĂ©tat de lâart. Toutes ces techniques ont ensuite Ă©tĂ© implĂ©mentĂ©es et Ă©valuĂ©es sur un jeu de test consĂ©quent
Contribution to emptiness checks for explicit model checking
L'approche automate pour le model checking de propriĂ©tĂ©s temporelles Ă temps linĂ©aire est une technique classique de vĂ©rification formelle de systĂšmes concurrents. Un systĂšme, ainsi qu'une propriĂ©tĂ© qu'on souhaite y vĂ©rifier, sont modĂ©lisĂ©s sous forme dâomega-automates reconnaissant des mots infinis. Des manipulations de ces automates (produit synchronisĂ© et test de vacuitĂ©) permettent d'Ă©tablir si le systĂšme vĂ©rifie la propriĂ©tĂ© ou non. Dans cette thĂšse nous nous focalisons sur un type particulier d'omega-automates qui permettent une reprĂ©sentation concise des propriĂ©tĂ©s d'Ă©quitĂ© faible: les automates de BĂŒchi gĂ©nĂ©ralisĂ©s basĂ©s sur les transitions (TGBA ou Transition-based Generalized BĂŒchi Automata). Dans un premier temps, nous brossons un aperçu des algorithmes de vĂ©rification existant et nous en proposons de nouveaux traitant efficacement les automates gĂ©nĂ©ralisĂ©s forts. Dans un second temps, l'analyse des composantes fortement connexes de l'automate de la propriĂ©tĂ© nous a conduit Ă Ă©laborer une dĂ©composition de cet automate. Cette dĂ©composition se focalise sur les automates multi-forces et permet une parallĂ©lisation naturelle des model-checkers. Enfin, nous avons proposĂ© les premiers tests de vacuitĂ© parallĂšles pour les automates gĂ©nĂ©ralisĂ©s. De plus, tous ces tests sont lock-free Ă la diffĂ©rence de ceux de lâĂ©tat de lâart. Toutes ces techniques ont ensuite Ă©tĂ© implĂ©mentĂ©es et Ă©valuĂ©es sur un jeu de test consĂ©quent.The automata-theoretic approach to linear time model-checking is a standard technique for formal verification of concurrent systems. The system and the property to check are modeled with omega-automata that recognizes infinite words. Operations overs these automata (synchronized product and emptiness checks) allows to determine whether the system satisfies the property or not. In this thesis we focus on a particular type of omega-automata that enable a concise representation of weak fairness properties: transitions-based generalized BĂŒchi automata (TGBA). First we outline existing verification algorithms, and we propose new efficient algorithms for strong automata. In a second step, the analysis of the strongly connected components of the property automaton led us to develop a decomposition of this automata. This decomposition focuses on multi-strength property automata and allows a natural parallelization for already existing model-checkers. Finally, we proposed, for the first time, new parallel emptiness checks for generalized BĂŒchi automata. Moreover, all these emptiness checks are lock-free, unlike those of the state-of-the-art. All these techniques have been implemented and then evaluated on a large benchmark
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