Search results for "NEC"
showing 10 items of 9363 documents
Superfluid weight and Berezinskii-Kosterlitz-Thouless transition temperature of twisted bilayer graphene
2019
We study superconductivity of twisted bilayer graphene with local and non-local attractive interactions. We obtain the superfluid weight and Berezinskii-Kosterlitz-Thouless (BKT) transition temperature for microscopic tight-binding and low-energy continuum models. We predict qualitative differences between local and non-local interaction schemes which could be distinguished experimentally. In the flat band limit where the pair potential exceeds the band width we show that the superfluid weight and BKT temperature are determined by multiband processes and quantum geometry of the band.
Modal analysis for random response of MDOF systems
1990
The usefulness of the mode-superposition method of multidegrees of freedom systems excited by stochastic vector processes is here presented. The differential equations of moments of every order are written in compact form by means of the Kronecker algebra; then the method for integration of these equations is presented for both classically and non-classically damped systems, showing that the fundamental operator available for evaluating the response in the deterministic analysis is also useful for evaluating the response in the stochastic analysis.
Solvability of the divergence equation implies John via Poincaré inequality
2014
Abstract Let Ω ⊂ R 2 be a bounded simply connected domain. We show that, for a fixed (every) p ∈ ( 1 , ∞ ) , the divergence equation div v = f is solvable in W 0 1 , p ( Ω ) 2 for every f ∈ L 0 p ( Ω ) , if and only if Ω is a John domain, if and only if the weighted Poincare inequality ∫ Ω | u ( x ) − u Ω | q d x ≤ C ∫ Ω | ∇ u ( x ) | q dist ( x , ∂ Ω ) q d x holds for some (every) q ∈ [ 1 , ∞ ) . This gives a positive answer to a question raised by Russ (2013) in the case of bounded simply connected domains. In higher dimensions similar results are proved under some additional assumptions on the domain in question.
Contributions of mean and shape of blood pressure distribution to worldwide trends and variations in raised blood pressure: A pooled analysis of 1018…
2018
Background: Change in the prevalence of raised blood pressure could be due to both shifts in the entire distribution of blood pressure (representing the combined effects of public health interventions and secular trends) and changes in its high-blood-pressure tail (representing successful clinical interventions to control blood pressure in the hypertensive population). Our aim was to quantify the contributions of these two phenomena to the worldwide trends in the prevalence of raised blood pressure. Methods: We pooled 1018 population-based studies with blood pressure measurements on 88.6 million participants from 1985 to 2016. We first calculated mean systolic blood pressure (SBP), mean dia…
Une nouvelle approche de classification de personnes à partir d'une plate-forme multi-kinect
2015
International audience; Dans ce papier nous présentons un descripteur 3D original pour la classification de personnes. Nous avons réalisé une plate-forme multi-kinect qui fait l'acquisition de nuages de points complets (c'est à dire selon une vue à 360°). Un post-traitement (suppression d'arrière-plan) isole les éléments qui sont candidats à représenter une personne. Notre descripteur exploite ces données et permet, au travers d'un classifieur SVM (Support Vector Machine), de classifier les personnes et de déterminer l'orientation du plan frontal de la personne. Il utilise la répartition spatiale et l'orientation des normales aux surfaces dans un procédé dérivé de celui des HOG (Histogram o…
How Do Mobile ICTs Enable Organizational Fluidity: Toward a Theoretical Framework
2017
Abstract The focus of this theoretical paper is to investigate how mobile information and communication technologies (ICTs) give rise to the notion of organizational fluidity. Drawing upon previous literature, five affordances of mobile ICTs − mobility, connectedness, interoperability, identifiability, and personalization − are discussed. Delving into the concept of organizational fluidity, the paper captures three dimensions of organizational fluidity, namely, team fluidity, task fluidity, and control fluidity. The paper then develops propositions on how different combinations of the mobile ICT affordances influence each of the dimensions of organizational fluidity. The contributions and i…
Replacing Project Managers in Information Technology Projects
2015
According to anecdotal evidence, project managers working on information technology (IT) projects are occasionally replaced, although the literature on information systems (IS) and project management (PM) makes little mention of it. With a view to narrowing this knowledge gap the authors examined the reasons behind the practice. The authors took an interpretive approach to the data gathering and analysis, and collected descriptions about replacing project managers (RPM) from interviews and questionnaires (n=43). The concept of contradiction served as a lens through which to identify the underlying reasons. Contradiction refers to statements asserting or expressing the opposite of another st…
Do videowikis on the web support better (constructivist) learning in the basics of information systems science?
2012
This paper describes the combination of a wiki and screen capture videos as a complementary addition to conventional lectures in an information management and information systems development course. Our basis was collaborative problem-based learning with the problems defined by students. The idea was that students were expected to find concepts or issues from four lecture themes which are not well-defined or clarified for them. The students worked in small groups of two or three students or they completed the coursework individually. First, the students selected the theme which was most unclear for them. Second, the students selected the problematic things from this area and created the pre…
Context–content systems of random variables : The Contextuality-by-Default theory
2016
Abstract This paper provides a systematic yet accessible presentation of the Contextuality-by-Default theory. The consideration is confined to finite systems of categorical random variables, which allows us to focus on the basics of the theory without using full-scale measure-theoretic language. Contextuality-by-Default is a theory of random variables identified by their contents and their contexts, so that two variables have a joint distribution if and only if they share a context. Intuitively, the content of a random variable is the entity the random variable measures or responds to, while the context is formed by the conditions under which these measurements or responses are obtained. A …
Design of a Cleaning Program for a PV Plant Based on Analysis of Energy Losses
2015
Solar photovoltaic (PV) energy has grown significantly over the past few years. However, despite the increase in installed capacity, this energy source still raises important concerns related to the variability of power production. The short-term effects such as cloud shadowing and supply interruptions, as well as long-term effects such as dust accumulation, seasonal variation, and ageing of PV modules, can cause variability of power production. Therefore, the analysis of all the variability sources in order to provide statistically consistent power production data is an important challenge. This study presents a methodology to analyze data from a PV plant in order to have an independent ev…