The lid method for exhaustive exploration of metastable states of complex systems

The `lid' algorithm performs an exhaustive exploration of neighborhoods of local energy minima of energy landscapes. This paper describes an implementation of the algorithm, including issues of parallel performance and scalability. To illustrate the versatility of the approach and to stress the common features present in landscapes of quite different systems, we present selected results for 1) a spin glass, 2) a ferromagnet, 3) a covalent network model for glassy systems, and 4) a polymer. The exponential nature of the local density of states found in these systems and its relation to the ordering transition is briefly commented upon.Comment: RevTeX, 11 pages, 1 figur

Seniors et tablettes interactives - Livre blanc

L’apparition des terminaux mobiles dotés d’écrans tactiles a constitué une véritable rupture dans les usages de l’Internet. Ces nouvelles interfaces simplifiées ont permis d’introduire une nouvelle « grammaire gestuelle » auprès de l’ensemble des utilisateurs. En introduisant une nouvelle forme de « mobilité domestique », ces terminaux ont aussi permis d’intégrer plus étroitement ces services à la vie quotidienne des citoyens. Plutôt que de créer des technologies spécifiquement dédiées aux seniors, il est désormais possible de faire évoluer les outils et les services « grand public » afin que les seniors puissent en bénéficier. En effet, l’ergonomie constitue désormais un facteur crucial pour la démocratisation des services de l’Internet. L’objectif de la Délégation aux Usages de l’Internet en publiant ce livre blanc est de permettre à l’ensemble des acteurs de l’Internet (constructeurs de terminaux et concepteurs de services mobiles) de mieux prendre en compte les besoins des seniors. Ce livre blanc a été élaboré à l’issue d’une étude menée par le laboratoire du CNRS Le Lutin avec l’association d’entreprises Silicon Sentier

Commissioning and performance of the LHCb Silicon Tracker

The LHCb Silicon Tracker is a silicon micro-strip detector with a sensitive area of 12 m2 and a total of 272k readout channels. The Silicon Tracker consists of two parts that use different detector modules. The detector installation was completed by early summer 2008 and the commissioning without beam has reached its final stage, successfully overcoming most of the encountered problems. Currently, the detector has more than 99% of the channels fully functioning. Commissioning with particles has started using beam-induced events from the LHC injection tests in 2008 and 2009. These events allowed initial studies of the detector performance. Especially, the detector modules could be aligned with an accuracy of about 20μm. Furthermore, with the first beam collisions that took place end of 2009 we could further study the performance and improve the alignment of the detector

Linqits: Big data on little clients

ABSTRACT We present LINQits, a flexible hardware template that can be mapped onto programmable logic or ASICs in a heterogeneous system-on-chip for a mobile device or server. Unlike fixed-function accelerators, LINQits accelerates a domainspecific query language called LINQ. LINQits does not provide coverage for all possible applications-however, existing applications (re-)written with LINQ in mind benefit extensively from hardware acceleration. Furthermore, the LINQits framework offers a graceful and transparent migration path from software to hardware. LINQits is prototyped on a 2W heterogeneous SoC called the ZYNQ processor, which combines dual ARM A9 processors with an FPGA on a single die in 28nm silicon technology. Our physical measurements show that LINQits improves energy efficiency by 8.9 to 30.6 times and performance by 10.7 to 38.1 times compared to optimized, multithreaded C programs running on conventional ARM A9 processors