Le Touquet - Paris-Plage, France
Le Touquet - Paris-Plage, France

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Ahmed I.,University Paris - Sud | Farha R.,CNRS Nanosciences Institute of Paris | Farha R.,ECE Paris Graduate School of Engineering | Goldmann M.,CNRS Nanosciences Institute of Paris | And 3 more authors.
Chemical Communications | Year: 2013

Films based on electrostatic interactions between tetracationic porphyrin and Dawson type polyoxometalate are formed by the so called layer-by-layer method. Their photovoltaic performances are investigated by photocurrent transient measurements which showed significant photocurrent response. © 2013 The Royal Society of Chemistry.


Schaming D.,University Paris - Sud | Farha R.,CNRS Nanosciences Institute of Paris | Farha R.,ECE Paris Graduate School of Engineering | Xu H.,Fudan University | And 4 more authors.
Langmuir | Year: 2011

Films based on electrostatic interactions between tetracationic zinc porphyrins, ZnOEP(py)4 4+ or ZnTMePyP4+, and the tetracobalt Dawson-derived sandwich polyanion αββα- [Co4(H2O)2(P2W15O 56)2]16- are formed by the so-called layer-by-layer method. These films have been characterized by UV-visible absorption spectroscopy, atomic force microscopy and electrochemistry. The composition of the film was measured by X-ray photoelectron spectrum (XPS). The XPS data confirm the presence of the expected elements. The photocatalytic properties of these films have been also studied for the reduction of silver and gold ions. Indeed, in these systems, porphyrins can be excited by visible light and then play the role of photosensitizers able to give electrons to POM known to be good catalysts. Silver nanowires and gold nanosheets have been obtained. © 2010 American Chemical Society.


Muller F.,ECE Paris Graduate School of Engineering | Muller F.,CEA Saclay Nuclear Research Center | Degrouard J.,University Paris - Sud | Jestin J.,CEA Saclay Nuclear Research Center | And 2 more authors.
Soft Matter | Year: 2012

The stabilisation of emulsified microemulsions using different concentrations of colloidal disk-like particles (Laponite) is investigated. The resulting structures are characterised by cryo-TEM, small-angle and very small-angle neutron scattering methods. We show that the Laponite colloids are effectively attached onto the droplet interfaces, creating a protective layer around them, dense enough to be statistically observed by means of neutron scattering, although the mean coverage remains still rather low. The mean size of the internally organised droplets does not change with the colloidal concentration (up to 1 wt%), and a few free colloids are found in the continuous water solvent. However, the colloids are shown to be able to deform the soft interfaces of the microemulsion phase to create droplets that are not always spherical, but can have angled interfaces. © The Royal Society of Chemistry 2012.


George L.,University Paris Est Creteil | Courbin P.,ECE Paris Graduate School of Engineering | Sorel Y.,French Institute for Research in Computer Science and Automation
Journal of Systems Architecture | Year: 2011

In this paper, we focus on the semi-partitioned scheduling of sporadic tasks with constrained deadlines and identical processors. We study two cases of semi-partitioning: (i) the case where the worst case execution time (WCET) of a job can be portioned, each portion being executed on a dedicated processor, according to a static pattern of migration; (ii) the case where the jobs of a task are released on a processor, 1 time out of p, where p is an integer at most equal to the number of processors, according to a round-robin migration pattern. The first approach has been investigated in the state-of-the-art by migrating a job at its local deadline, computed from the deadline of the task it belongs to. We study several local deadline assignment heuristics (fair, based on processor utilization and based on the minimum acceptable local deadline for a job on a processor). In both cases, we propose feasibility conditions for the schedulability of sporadic tasks scheduled using earliest deadline first (EDF) semi-partitioned scheduling. We show that the load function used for global scheduling to establish the feasibility of sporadic task sets exhibits interesting properties in the semi-partitioning context. We carry out simulations to study the performance of the two approaches in terms of success rate and number of migrations, for platforms composed of four and eight processors. We compare the performance of these semi-partitioned heuristics with the performance of classical partitioned scheduling algorithms and with a global scheduling heuristic which is currently considered to have good performances. © 2010 Elsevier B.V. All rights reserved.


Courbin P.,ECE Paris Graduate School of Engineering | Lupu I.,Roosevelt University | Goossens J.,Roosevelt University
Real-Time Systems | Year: 2013

In this paper we study the scheduling of parallel and real-time recurrent tasks on multiprocessor platforms. Firstly, we propose a new parallel task model which allows recurrent tasks to be composed of several phases, each one composed of several threads. Each thread requires a single processor for execution and can be scheduled simultaneously. We then propose an algorithm to transpose popular Fork-Join task model to our MPMT task model. Secondly, we define several kinds of real-time schedulers that can be applied to our parallel task model. We distinguish between two scheduling classes: Hierarchical schedulers and Global Thread schedulers. We present and prove correct an exact schedulability test for each class. Lastly, we also evaluate the performance of our scheduling paradigm in comparison with Gang scheduling by means of simulations. In this work we extend the work of Lupu and Goossens in Scheduling of hard real-time multi-thread periodic tasks (Real-Time and Network Systems, 2011) which considers mono-phase multi-thread task model. We extend their previous results to a Multi-Phase Multi-Thread task model. © 2012 Springer Science+Business Media New York.


Ataman S.,ECE Paris Graduate School of Engineering
European Physical Journal D | Year: 2015

Abstract In this paper we describe a Fabry-Perot interferometer in the language of quantum optics. We go on to model the Fabry-Perot interferometer as a beam splitter having frequency dependent transmissivity and reflectivity coefficients. The antibunching, a totally non-classical effect, is to be expected if one excites this interferometer with carefully frequency-selected single photons arriving simultaneously from opposite directions. For carefully chosen frequencies, even slightly different color single photons should be able to show this effect, as long as the photon counters are not frequency selective. Graphical abstract: [Figure not available: see fulltext.] © 2015 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Ataman S.,ECE Paris Graduate School of Engineering
European Physical Journal D | Year: 2015

In this paper we describe and thoroughly discuss three reported experiments in quantum optics (QO) involving interferometers and non-linear crystals. We show that by using a graphical method and an over-simplified model of the parametric down-conversion process, we arrive to explain all the important results reported in the respective papers. Indistinguishability is discussed in the case of separable/non-separable (i.e. entangled) quantum systems and our interpretation is sometimes at variance with the one given by the authors reporting the experiments. © 2015 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Ataman S.,Extreme Light Infrastructure Nuclear Physics ELI NP | Ataman S.,ECE Paris Graduate School of Engineering
European Physical Journal D | Year: 2016

Abstract: In this paper we propose and analyse a Gedankenexperiment involving three non-linear crystals and two objects inserted in the idler beams. We show that, besides the behaviour that can be extrapolated from previous experiments involving two crystals and one object, we are able to predict a new effect: under certain circumstances, one of the objects can be rendered undetectable to any single detection rate on the signal photons with discarded idler photons. This effect could find applications in future developments of quantum imaging techniques. Graphical abstract: [Figure not available: see fulltext.] © 2016, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Ataman S.,ECE Paris Graduate School of Engineering
European Physical Journal D | Year: 2014

Often cited dictums in Quantum Mechanics include observation disturbance causes loss of interference and ignorance is interference. In this paper we propose and describe a series of experiments with modified Mach-Zehnder interferometers showing that one has to be careful when applying such dictums. We are able to show that without interacting in any way with the light quantum (or quanta) expected to behave wave-like, interference fringes can be lost by simply gaining (or having the potential to gain) the which-path knowledge. Erasing this information may revive the interference fringes. Delayed choice can be added, arriving to an experiment in line with Wheeler's original proposal. We also show that ignorance is not always synonym with having the interference fringes. The often-invoked collapse of the wavefunction is found to be a non-necessary ingredient to describe our experiments. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag.


Ataman S.,ECE Paris Graduate School of Engineering
European Physical Journal D | Year: 2014

In this paper we describe a novel, graphical method, allowing the fast computation of field operator transformations for linear lossless optical devices in quantum optics (QO). The advantage of this method grows with the complexity of the considered optical setup. As case studies we examine the field operator transformations for the beam splitter (BS), the Mach-Zehnder interferometer (MZI) and the double MZI. We consider the simple case with monochromatic input light, as well as extensions to the non-monochromatic case. © EDP Sciences, Società Italiana di Fisica, Springer-Verlag.

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