Search results for "Open"

Novel group 4b ansa-metallocene complexes with the shortest bridge: [1,1′-isopropylydene-3,3′-di-t.Bu-bis(η5-cyclopentadienyl)] Ti and Zr dichlorides

1997

Abstract Reaction of [1,1′-isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienide)] dilithium with TiCl3, followed by treatment with HCl, and ZrCl4 in various solvent mixtures in the temperature range 0–50°C gives corresponding ansa-metallocene dichlorides as mixtures of the anti/syn-isomers, 1:1. The crystal and molecular structures of three of the four isomers were determined, i.e. rac(anti)-[1,1′-isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienyl)]TiCl2, space group B2/b, rac(anti)-[1,1′-isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienyl)]ZrCl2, space group P212121, and meso(syn)-1,1′-[isopropylidene-3,3′-di-tert.butyl-bis(η5-cyclopentadienyl)]ZrCl2, space group P21/n.

Towards A Twitter Observatory: A Multi-Paradigm Framework For Collecting, Storing And Analysing Tweets

2016

International audience; In this article we show how a multi-paradigm framework can fulfil the requirements of tweets analysis and reduce the waiting time for researchers that use computational resources and storage systems to support large-scale data analysis. The originality of our approach is to combine concerns about data harvesting, data storage, data analysis and data visualisation into a framework that supports inductive reasoning in multidisciplinary scientific research. Our main contribution is a polyglot storage system with a generic data model to support logical data independence and a set of tools that can provide a suitable solution for mixing different types of algorithms in or…

Towards a methodology for semantic and context-aware mobile learning

2013

International audience; Internet and mobile devices open the way towards mobile learning (m-learning), offering new opportunities to extend learning beyond the traditional teacher-led classroom. M-learning is not only any form of teaching or studying that takes place when the user interacts with a mobile device. It is more than just using a mobile device to access resources and communicate with others. It should take account of the constant mobile situation of the learner. The challenge here is to exploit this continually changing situation with a system that can dynamically recognize and adapt educational resources and services to the "context" in which the learner operates (localization, …

Fractal Weyl law for open quantum chaotic maps

2014

We study the semiclassical quantization of Poincar\'e maps arising in scattering problems with fractal hyperbolic trapped sets. The main application is the proof of a fractal Weyl upper bound for the number of resonances/scattering poles in small domains near the real axis. This result encompasses the case of several convex (hard) obstacles satisfying a no-eclipse condition.

Modelling of microcracked bodies using the concept of crack opening mode

2010

Incorporation of the [(pentamethylcyclopentadienyl) (2,2-bipyridyl)(aquo)rhodium(III)] complex into DPPC vesicles studied by a kinetic method

2008

Representing and Reasoning for Spatiotemporal Ontology Integration

2004

International audience; The World-Wide Web hosts many autonomous and heterogeneous information sources. In the near future each source may be described by its own ontology. The distributed nature of ontology development will lead to a large number of local ontologies covering overlapping domains. Ontology integration will then become an essential capability for effective interoperability and information sharing. Integration is known to be a hard problem, whose complexity increases particularly in the presence of spatiotemporal information. Space and time entail additional problems such as the heterogeneity of granularity used in representing spatial and temporal features. Spatio-temporal ob…

Topological properties of cellular automata on trees

2012

We prove that there do not exist positively expansive cellular automata defined on the full k-ary tree shift (for k>=2). Moreover, we investigate some topological properties of these automata and their relationships, namely permutivity, surjectivity, preinjectivity, right-closingness and openness.

The Influence of the feedback control of the hexapod platform of the SAAM dynamic driving simulator on neuromuscular dynamics of the drivers

2012

Multi sensorial cues (visual, auditory, haptic, inertial, vestibular, neuromuscular) [Ang2] play important roles to represent a proper sensation (objectively) and so a perception (subjectively as cognition) in driving simulators. Driving simulator aims at giving the sensation of driving as in a real case. For a similar situation, the driver has to react in the same way as in reality in terms of ‘self motion’. To enable this behavior, the driving simulator must enhance the virtual immersion of the subject in the driving situation. The subject has to perceive the motion of his own body in the virtual scene of the virtual car as he will have in a real car. For that reason, restituting the iner…

Geometric Optimal Control of Simple Quantum Systems

2011

International audience