Search results for "TOPOLOGY"

Crystal structure and absolute configuration of (4S,5R,6S)-4,5,6-trihydroxy-3-methylcyclohex-2-enone (gabosine H)

2017

The absolute configuration of the title compound, determined as 4S,5R,6S on the basis of the synthetic pathway, was confirmed by single-crystal X-ray diffraction. The mol­ecule is formed by a substituted six-membered cyclo­hexene ring adopting an envelope conformation and substituted by carbonyl, methyl and hydroxyl groups. The supra­molecular structure is mainly built by a combination of O—H⋯O and weaker C—H⋯O hydrogen bonds.

Geometry and quasisymmetric parametrization of Semmes spaces

2011

We consider decomposition spaces R 3 /G that are manifold factors and admit defining sequences consisting of cubes-with-handles of finite type. Metrics on R 3 /G constructed via modular embeddings of R 3 /G into a Euclidean space promote the controlled topology to a controlled geometry. The quasisymmetric parametrizability of the metric space R 3 /G×R m by R 3+m for any m ≥ 0 imposes quantitative topological constraints, in terms of the circulation and the growth of the cubes-with-handles, on the defining sequences for R 3 /G. We give a necessary condition and a sufficient condition for the existence of such a parametrization. The necessary condition answers negatively a question of Heinone…

Architetture del divenire. Innovazioni contemporanee/Emerging Architecture. Contemporary Innovations (presentazione di Giuseppe Pellitteri) - Quadern…

2014

La posizione assunta dall'architettura all'inizio del ventunesimo secolo è ambigua e così la forma degli edifici che ambiscono a convogliare significati. Il processo di radicale trasformazione dell’architettura, avvenuto sin dal primo Novecento, quale conseguenza della graduale sostituzione delle tecniche edilizie tradizionali con le tecniche “moderne”, ha subito un notevole slancio nell'ultimo ventennio, per effetto del crescente mutamento tecnologico. I materiali, le tecniche costruttive e l’innovazione tecnologica hanno condizionato sensibilmente ed irreversibilmente il pensiero architettonico, producendo in questi ultimi anni nuove espressività linguistiche del tutto “insolite” rispetto…

Resistant microbial co-occurrence patterns inferred by network topology

2015

Natural induction: An objective bayesian approach

2009

The statistical analysis of a sample taken from a finite population is a classic problem for which no generally accepted objective Bayesian results seem to exist. Bayesian solutions to this problem may be very sensitive to the choice of the prior, and there is no consensus as to the appropriate prior to use.

Atlas construction and image analysis using statistical cardiac models

2010

International audience; This paper presents a brief overview of current trends in the construction of population and multi-modal heart atlases in our group and their application to atlas-based cardiac image analysis. The technical challenges around the construction of these atlases are organized around two main axes: groupwise image registration of anatomical, motion and fiber images and construction of statistical shape models. Application-wise, this paper focuses on the extraction of atlas-based biomarkers for the detection of local shape or motion abnormalities, addressing several cardiac applications where the extracted information is used to study and grade different pathologies. The p…

Influence of geometric variations on LV activation times: A study on an atlas-based virtual population

2010

We present the fully automated pipeline we have developed to obtain electrophysiological simulations of the heart on a large atlas-based virtual population. This virtual population was generated from a statistical model of left ventricular geometry, represented by a surface model. Correspondence between tetrahedralized volumetric meshes was obtained using Thin Plate Spline warps. Simulations are based on the fast solving of Eikonal equations, and stimulation sites correspond to physiological activation. We report variations of total activation time introduced by geometry, as well as variations in the location of last activation. The obtained results suggest that the total activation time ha…

Nonlinear Relaxation in Population Dynamics

2001

We analyze the nonlinear relaxation of a complex ecosystem composed of many interacting species. The ecological system is described by generalized Lotka-Volterra equations with a multiplicative noise. The transient dynamics is studied in the framework of the mean field theory and with random interaction between the species. We focus on the statistical properties of the asymptotic behaviour of the time integral of the i-th population and on the distribution of the population and of the local field.

Topological surface wave metamaterials for robust vibration attenuation and energy harvesting

2021

International audience; We propose topological metamaterials working in Hertz frequency range, constituted of concrete pillars on the soil ground in a honeycomb lattice. Based on the analog of the quantum valley Hall effect, a non-trivial bandgap is formed by breaking the inversion symmetry of the unit cell. A topological interface is created between two different crystal phases whose robustness against various defects and disorders is quantitatively analyzed. Finally, we take advantage of the robust and compact topological edge state for designing a harvesting energy device. The results demonstrate the functionality of the proposed structure for both robust surface vibration reduction and …

Classification of Solutions to the Minimum Energy Problem in One Dimensional Sensor Networks

2016

We classify of the minimum energy problem in one dimensional wireless sensor networks for the data transmission cost matrix which is a power function of the distance between transmitter and receiver with any real exponent. We show, how these solutions can be utilized to solve the minimum energy problem for the data transmission cost matrix which is a linear combination of two power functions. We define the minimum energy problem in terms of the sensors signal power, transmission time and capacities of transmission channels. We prove, that for the point-to-point data transmission method utilized by the sensors in the physical layer, when the transmitter adjust the power of its radio signal t…