Structural aspects of tilings

In this paper, we study the structure of the set of tilings produced by any given tile-set. For better understanding this structure, we address the set of finite patterns that each tiling contains. This set of patterns can be analyzed in two different contexts: the first one is combinatorial and the other topological. These two approaches have independent merits and, once combined, provide somehow surprising results. The particular case where the set of produced tilings is countable is deeply investigated while we prove that the uncountable case may have a completely different structure. We introduce a pattern preorder and also make use of Cantor-Bendixson rank. Our first main result is that a tile-set that produces only periodic tilings produces only a finite number of them. Our second main result exhibits a tiling with exactly one vector of periodicity in the countable case.Comment: 11 page

Detection of an anomalous cluster in a network

We consider the problem of detecting whether or not, in a given sensor network, there is a cluster of sensors which exhibit an "unusual behavior." Formally, suppose we are given a set of nodes and attach a random variable to each node. We observe a realization of this process and want to decide between the following two hypotheses: under the null, the variables are i.i.d. standard normal; under the alternative, there is a cluster of variables that are i.i.d. normal with positive mean and unit variance, while the rest are i.i.d. standard normal. We also address surveillance settings where each sensor in the network collects information over time. The resulting model is similar, now with a time series attached to each node. We again observe the process over time and want to decide between the null, where all the variables are i.i.d. standard normal, and the alternative, where there is an emerging cluster of i.i.d. normal variables with positive mean and unit variance. The growth models used to represent the emerging cluster are quite general and, in particular, include cellular automata used in modeling epidemics. In both settings, we consider classes of clusters that are quite general, for which we obtain a lower bound on their respective minimax detection rate and show that some form of scan statistic, by far the most popular method in practice, achieves that same rate to within a logarithmic factor. Our results are not limited to the normal location model, but generalize to any one-parameter exponential family when the anomalous clusters are large enough.Comment: Published in at http://dx.doi.org/10.1214/10-AOS839 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Phase-space methods in nuclear reactions around the Fermi energy

Some prescriptions for in-medium complex particle production in nuclear reactions are proposed. They have been implemented in two models to simulate nucleon-nucleus (nIPSE) and nucleus-nucleus (HIPSE) reactions around the Fermi energy \cite{Lac04,Lac05}. Our work emphasizes the effect of randomness in cluster formation, the importance of the nucleonic Fermi motion as well as the role of conservation laws. The key role of the phase-space exploration before and after secondary decay is underlined. This is illustrated in the case of two debated issues: the memory loss of the entrance channel in central collisions and the $(N,Z)$ partitions after the pre-equilibrium stage.Comment: Proceedings of the IWM2005 workshop, Catane (Italy), Nov. 2005. DOWNLOAD HIPSE program at: http://caeinfo.in2p3.fr/theorie/theory_lacroix.htm

Fixed Parameter Undecidability for Wang Tilesets

Deciding if a given set of Wang tiles admits a tiling of the plane is decidable if the number of Wang tiles (or the number of colors) is bounded, for a trivial reason, as there are only finitely many such tilesets. We prove however that the tiling problem remains undecidable if the difference between the number of tiles and the number of colors is bounded by 43. One of the main new tool is the concept of Wang bars, which are equivalently inflated Wang tiles or thin polyominoes.Comment: In Proceedings AUTOMATA&JAC 2012, arXiv:1208.249

Ray-on, an On-Site Photometric Augmented Reality Device

This paper describes the work done to improve the visitor’s experience while visiting the historical site of Cluny abbey, in Burgundy (France). The church of this abbey, founded in 910 and which was the biggest church of Christendom until the 15th century, has been almost completly destroyed after the French Revolution and so is hard to figure out for the visitors. The usage of virtual reality is one of the way to improve the understanding of the architecture of the site

Spherical angular spectrum and the fractional order Fourier transform

International audienceThe notion of a spherical angular spectrum leads to the decomposition of the field amplitude on a spherical emitter into a sum of spherical waves that converge onto the Fourier sphere of the emitter. Unlike the usual angular spectrum, the spherical angular spectrum is propagated as the field amplitude, in a way that can be expressed by a fractional order Fourier transform

Disseccionant "Architecture Principe", manifest projectual de la funció obliqua

L’estudi d’una publicació plena d’envits arquitectònics i socials com la del grup Architecture Principe, iniciada als anys seixanta, pretén demostrar la importància de l’obra impresa en la consolidació d’una trajectòria projectual. Avantguardista en la manera d’adreçar-se al seu lector, la multiplicitat de missatges transmesos pels escrits i represen- tacions gràfiques ordenades per Claude Parent i Paul Virilio a la revista, ens porta a qües- tionar-nos sobre la influència del treball publicat en el panorama actual de l’arquitectura contemporània. La investigació proposada al llarg d’aquest treball es centra en una dissecció analítica de les deu revistes publicades pel col·lectiu de pensadors-creadors els anys 1966 i 1996: la comprensió del contingut teòric, de la maquetació gràfica i de les decisions artístiques de la obra quedant-se essencials per entendre el impacte conceptual en la propagació de les seves idees dins de l’àmbit de la Teoria de l’Arquitectura. A través d’aquesta recerca, la nostra exposició s’amplia amb l’aportació d’una nova revista permetent d’aprofundir la reflexió en un context actual, emfatitzant un punt de vista crític sobre la transgressió del treball realitzat per Parent i Virilio a través de les èpoques. Aquest treball s’estén, doncs, més enllà de l’obra publicada, en l’aportació ma- terial d’una reinterpretació teoricogràfica dels principis fonamentals de la Funció Obliqua.El estudio de una publicación llena de envites arquitectónicos y sociales como la del grupo Architecture Principe, iniciada en los años sesenta, pretende demostrar la importancia de la obra impresa en la consolidación de una trayectoria de proyecto. Vanguardista en la forma de dirigirse a su lector, la multiplicidad de mensajes transmitidos por los escritos y representaciones gráficas ordenadas por Claude Parent y Paul Virilio en la revista, nos lleva a cuestionarnos sobre la influencia del trabajo publicado en el panorama actual de la arquitectura contemporánea. La investigación propuesta a lo largo de este trabajo se centra en una disección analítica de las diez revistas publicadas por el colectivo de pensadores-creadores en los años 1966 y 1996: la comprensión del contenido teórico, de la maquetación gráfica y de las decisiones artísticas de la obra quedándose esenciales para entender el impacto conceptual en la propagación de sus ideas en el ámbito de la Teoría de la Arquitectura. A través de esta investigación, nuestra exposición se amplía con la aportación de una nueva revista, permitiendo profundizar la reflexión en un contexto actual, enfatizando un punto de vista crítico sobre la transgresión del trabajo realizado por Parent i Virilio a través de las épocas. Este trabajo se extiende, pues, más allá de la obra publicada, en la aportación material de una reinterpretación teórico-gráfica de los principios fundamentales de la Función Obliqua.The study of a publication with architectural and societal stakes, such as that of the group Architecture Principe iniciated in the 1960s, seeks to demonstrate the impor- tance of writing inked materially in the concretization of a projectual trajectory. Avant-garde in the way it addresses its reader, the multiplicity of messages transmitted by the writings and graphic representations commissioned by Claude Parent and Paul Virilio leads us to examine the influence of the journalistic work on the current landscape of contemporary architecture. The investigation proposed in this work focuses on the analytical dissection into the ten publications of the collective from 1966 to 1996: the understanding and explana- tion of the theoretical contents, the layouts, the artistic and literary choices of the authors remain paramount in order to understand the impact in the propagation of concepts within architectural theory. Through this research, our study is extended by the contribution of a new review allowing us to deepen our reflection in a present context, accentuating a critical point of view on the transgression of the work led by Parent and Virilio through the ages. This work thus extends beyond the published work, in the material contribution of a theoretical-gra- phic reinterpretation of the founding principles of the Oblique Function, which were first manifested in 1966.Award-winnin

3D-FE electro-thermo-magnetic modeling of automotive power electronic modules -Wire- bonding and Copper clip technologies comparison

International audienceIn this work, we propose an electromagnetic and thermal 3D-Finit-Element Modeling and simulation methodology, under COMSOL Multiphysics, applied to a phase-leg high current power modules for automotive EV HEV applications, whose technical specifications are similar but with two different interconnection types [1] [2]. This article compares them in terms of stray electrical resistances and inductances but also in terms of thermal resistances and impedances. It will be shown in this article that the introduction of a copper clips only slightly modify the thermal extraction while the electrical performance will be greatly improved

Simultaneous pressure-volume measurements using optical sensors and MRI 1 for left ventricle function assessment during animal experiment 2

International audienceSimultaneous pressure and volume measurements enable the extraction of valuable parameters for left ventricle function assessment. Cardiac MR has proven to be the most accurate method for volume estimation. Nonetheless, measuring pressure simultaneously during MRI acquisitions remains a challenge given the magnetic nature of the widely used pressure transducers. In this study we show the feasibility of simultaneous in vivo pressure-volume acquisitions with MRI using optical pressure sensors. Pressure-volume loops were calculated while inducing three inotropic states in a sheep and functional indices were extracted, using single beat loops, to characterize systolic and diastolic performance. Functional indices evolved as expected in response to positive inotropic stimuli. The end-systolic elastance, representing the contractility index, the diastolic myocardium compliance, and the cardiac work efficiency all increased when inducing inotropic state enhancement. The association of MRI and optical pressure sensors within the left ventricle successfully enabled pressure-volume loop analysis after having respective data simultaneously recorded during the experimentation without the need to move the animal between each inotropic state

Qualitative and Semiquantitative Assessment of Exposure to Engineered Nanomaterials within the French EpiNano Program: Inter- and Intramethod Reliability Study

The relatively recent development of industries working with nanomaterials has created challenges for exposure assessment. In this article, we propose a relatively simple approach to assessing nanomaterial exposures for the purposes of epidemiological studies of workers in these industries. This method consists of an onsite industrial hygiene visit of facilities carried out individually and a description of workstations where nano-objects and their agglomerates and aggregates (NOAA) are present using a standardized tool, the Onsite technical logbook. To assess its reliability, we implemented this approach for assessing exposure to NOAA in workplaces at seven workstations which synthesize and functionalize carbon nanotubes. The prediction of exposure to NOAA using this method exhibited substantial agreement with that of the reference method, the latter being based on an onsite group visit, an expert’s report and exposure measurements (Cohen kappa = 0.70, sensitivity = 0.88, specificity = 0.92). Intramethod comparison of results for exposure prediction showed moderate agreement between the three evaluators (two program team evaluators and one external evaluator) (weighted Fleiss kappa = 0.60, P = 0.003). Interevaluator reliability of the semiquantitative exposure characterization results was excellent between the two evaluators from the program team (Spearman rho = 0.93, P = 0.03) and fair when these two evaluators’ results were compared with the external evaluator’s results. The project was undertaken within the framework of the French epidemiological surveillance program EpiNano. This study allowed a first reliability assessment of the EpiNano method. However, to further validate this method a comparison with robust quantitative exposure measurement data is necessary