Switching dynamics of spatial solitary wave pixels

Separatrices and scaling laws in the switching dynamics of spatial solitary wave pixels are investigated. We show that the dynamics in the full model are similar to those in the plane-wave limit. Switching features may be indicated and explained by the motion of the (complex) solitary wave amplitude in the phase plane. We report generalization, into the domain of transverse effects, of the pulse area theorem for the switching process and a logarithmic law for the transient dynamics. We also consider, for what is the first time to our knowledge, phase-encoded address of solitary pixels and find that a near-square-wave temporal switching pattern is permitted without (transverse) cross switching

Le pastoralisme antique autour du col du Petit-Saint-Bernard

International audienceCet article fait le bilan des recherches archéologiques entreprises autour du col du Petit-Saint-Bernard, dans une réflexion plus générale sur le pastoralisme antique

Les sociétés alpines à l'époque romaine au travers des types d'habitat et des modes de construction

International audiencecet article propose une réflexion sur l'emploi des modes et des techniques de construction pour évaluer les changements que connaissent les sociétés alpines à l'époque romain

Producing and Living the City in Vietnam

International audienceIn a world where more than 50% of the population lives in cities, Vietnam and its current 34% of urban dwellers remains associated with rurality in the global imaginary. But this last figure should be put into perspective: after decades of de-urbanisation under the socialist regime the national urban growth is now exploding; the country’s urban population has doubled since 1980, with an official average growth of 3.4% per year. Beyond this steady demographic development, urbanised areas multiplied by between 1995 and 2010.4 Most of the urban growth takes place in and around Hanoi and Ho Chi Minh City (HCMC), even though secondary cities are also engaged in a rebalancing process. Today these two main metropolises of the country have respectively 7 and 7.9 million inhabitants. In addition, since the introduction of đổi mới reforms in the mid-1980s, cities have been officially recognised as the engine of national economic growth by the Communist Party of Vietnam (CPV), which leads the country.In this renewed context, our Focus offers a fresh perspective on the production of urban forms, the reconfiguration of local management, and the renegotiation of daily practices in Vietnamese cities. Our intention is not only to highlight the path-breaking transformations taking place in Vietnam today, but also to contribute to the ‘Asianisation’ of urban studies paradigms through grounded analysis and interpretation, and to discuss an alternative theoretical framework, based on extensive fieldwork in Vietnamese cities and neighbourhoods

Modeling power in multi-functionality sensor network applications

Rachit Agarwal, Rafael V. Martinez-Catala, Sean Harte, Cedric Segard, Brendan O'Flynn, "Modeling Power in Multi-functionality Sensor Network Applications," sensorcomm, pp.507-512, 2008 Proceedings of the Second International Conference on Sensor Technologies and Applications, August 25-August 31 2008, Cap Esterel, FranceWith the migration of a Wireless Sensor Network (WSN) over various evolving applications, power estimation and profiling during the design cycle become critical issues and present hurdles in reducing the design time. Furthermore, with a growing size of the network, simulating the behavior of each sensor node is not feasible. It is important to devise an approach that provides a network-wide picture of power consumption and of variations in power usage under changes in the network and/or node application in the network. In this paper, we present a modular power estimation technique which simplifies the power modeling of any sensor network application. In particular, we are interested in analyzing the behavior of power consumption if one or more modules of the WSN platform in the application are changed during the design cycle or after the deployment. The proposed technique is susceptible to applications changes on the fly and is particularly beneficial in networks with large number of nodes. We perform experiments modifying parameters of a ZigBee based sensor network application such as packet size, sampling rate, functionality (encryption) and sensor types. We present the results, demonstrating an error less than 3% in all the experiments performed, and insights into the results

Control of superluminal transit through a heterogeneous medium

We consider pulse propagation through a two component composite medium (metal inclusions in a dielectric host) with or without cavity mirrors. We show that a very thin slab of such a medium, under conditions of localized plasmon resonance, can lead to significant superluminality with detectable levels of transmitted pulse. A cavity containing the heterogeneous medium is shown to lead to subluminal-to-superluminal transmission depending on the volume fraction of the metal inclusions. The predictions of phase time calculations are verified by explicit calculations of the transmitted pulse shapes. We also demonstrate the independence of the phase time on system width and the volume fraction under specific conditions.Comment: 21 Pages,5 Figures (Published in Journal of Modern Optics

Superluminal, subluminal, and negative velocities in free-space electromagnetic propagation

In this Chapter the time-domain analysis of the velocity of the electromagnetic field pulses generated by a spatially compact source in free space is presented. Recent simulations and measurements of anomalous superluminal, subluminal, and negative velocities are discussed. It is shown that such velocities are local and instantaneous in nature and do not violate either causality or special relativity. Although these effects are mainly confined to the near- and intermediate-field zones, some of them seem paradoxical and still lack adequate physical interpretation.Comment: This is an extended account (21 pages, 9 figures) of my previous work: PRL 102, 02040

Peuplement, pastoralisme et modes d'exploitation de la moyenne et haute montagne depuis la Préhistoire dans le Parc National des Écrins

Cet article fait le bilan des travaux entrepris depuis la fin des années 1990 dans deux secteurs de moyenne et haute montagne des Alpes du Sud. Il restitue une histoire sur la longue durée de l'occupation de la montagne et discute la façon dont ses territoires ont été exploités