Search results for "Linear"
showing 10 items of 7165 documents
Efficient Modeling of NMR Parameters in Carbon Nanosystems
2015
Rapid growth of nanoscience and nanotechnology requires new and more powerful modeling tools. Efficient theoretical modeling of large molecular systems at the ab initio and Density Functional Theory (DFT) levels of theory depends critically on the size and completeness of the basis set used. The recently designed variants of STO-3G basis set (STO-3Gel, STO-3Gmag), modified to correctly predict electronic and magnetic properties were tested on simple models of pristine and functionalized carbon nanotube (CNT) systems and fullerenes using the B3LYP and VSXC density functionals. Predicted geometries, vibrational properties, and HOMO/LUMO gaps of the model systems, calculated with typical 6-31G…
A ‘TVD-like’ Scheme for Conservation Laws with Source Terms
2008
The theoretical foundations of high-resolution TVD schemes for homogeneous scalar conservation laws and linear systems of conservation laws have been firmly established through the work of Harten [5], Sweby [11], and Roe [9]. These TVD schemes seek to prevent an increase in the total variation of the numerical solution, and are successfully implemented in the form of flux-limiters or slope limiters for scalar conservation laws and systems. However, their application to conservation laws with source terms is still not fully developed. In this work we analyze the properties of a second order, flux-limited version of the Lax-Wendroff scheme preserving steady states [3]. Our technique is based …
Locally convex quasi *-algebras with sufficiently many *-representations
2012
AbstractThe main aim of this paper is the investigation of conditions under which a locally convex quasi ⁎-algebra (A[τ],A0) attains sufficiently many (τ,tw)-continuous ⁎-representations in L†(D,H), to separate its points. Having achieved this, a usual notion of bounded elements on A[τ] rises. On the other hand, a natural order exists on (A[τ],A0) related to the topology τ, that also leads to a kind of bounded elements, which we call “order bounded”. What is important is that under certain conditions the latter notion of boundedness coincides with the usual one. Several nice properties of order bounded elements are extracted that enrich the structure of locally convex quasi ⁎-algebras.
Functional linear regression with functional rensponse application to prediction of electricity consumption
2008
Functional linear regression model linking observations of a functional response variable with measurements of an explanatory functional variable is considered. The slope function is estimated with a tensor product splines. Some computational issues are addressed by means of a simulation study. This model serves to analyze a real data set concerning electricity consumption in Sardinia. The interest lies in predicting either incoming weekend or incoming weekdays consumption curves if actual weekdays consumption is known.
Functional Principal Components Analysis with Survey Data
2008
This work aims at performing Functional Principal Components Analysis (FPCA) with Horvitz-Thompson estimators when the observations are curves collected with survey sampling techniques. FPCA relies on estimations of the eigenelements of the covariance operator which can be seen as nonlinear functionals. Adapting to our functional context the linearization technique based on the influence function developed by Deville (1999), we prove that these estimators are asymptotically design unbiased and convergent. Under mild assumptions, asymptotic variances are derived for the FPCA’ estimators and convergent estimators of them are proposed. Our approach is illustrated with a simulation study and we…
Ephaptic coupling of myelinated nerve fibers
2001
Numerical predictions of a simple myelinated nerve fiber model are compared with theoretical results in the continuum and discrete limits, clarifying the nature of the conduction process on an isolated nerve axon. Since myelinated nerve fibers are often arranged in bundles, this model is used to study ephaptic (nonsynaptic) interactions between impulses on parallel fibers, which may play a functional role in neural processing.
Predictors and mediators of differences in soft drinks consumption according to gender and plans of further education among Norwegian secondary-schoo…
2013
AbstractObjectiveTo explore mediators of gender and educational differences in sugar-sweetened soft drinks consumption (SDC) and whether gender and level of future education moderate the associations of accessibility, modelling, attitudes and preferences with SDC.DesignA cross-sectional school-based survey within the Fruits and Vegetables Makes the Marks (FVMM) project from 2005.SettingThe questionnaires were completed by the pupils in the classroom guided by a trained project worker during one class session. The questionnaire included questions on SDC (times/week), the potential mediators and moderators. Multilevel linear regression models were used to calculate the mediating and moderatin…
Edelstein-Suzuki-type resuls for self-mappings in various abstract spaces with application to functional equations
2016
Abstract The fixed point theory provides a sound basis for studying many problems in pure and applied sciences. In this paper, we use the notions of sequential compactness and completeness to prove Eldeisten-Suzuki-type fixed point results for self-mappings in various abstract spaces. We apply our results to get a bounded solution of a functional equation arising in dynamic programming.
'A Difficult School Text in Anglo-Saxon England: The Third Book of Abbo’s Bella Parisiacae urbis', in Leeds Studies in English 37 (2006)
2006
Si prendono in esame le glosse interlineari in inglese antico al terzo libro dei Bella Parisiacae urbis di Abbone di San Germano, attestate da due manoscritti anglosassoni. Le scelte del glossatore sono valutate alla luce delle difficoltà insite nel testo latino di Abbone, particolarmente complesso, specialmente dal punto di vista del lessico, analizzando, in particolare la resa, di analogium, anabola, abacus, abaso, baccaulus, choraula e uxorius. Le rispettive glosse anglosassoni sono esaminate nell’economia dell’intera glossatura e valutate alla luce dell’uso didattico della versione interlineare in volgare. Il numero della rivista è stato dedicato alla Prof. Joyce Hill, già professore or…
Adaptive Control of a Gas Turbine Engine for Axial Compressor Faults
1996
An adaptive control system for a gas turbine engine which diagnoses conditions of axial compressor faults is proposed and analyzed. Nonlinear models of the gas turbine, neural networks and genetic algorithms are used in this research. The adaptive control system minimizes the reduction in gas turbine performance deriving from non-destructive faults. In the absence of faults, the system automatically performs the optimization of the engine between overhauls. Improvements concern the definition of adaptive control with faults in progress, and the real-time optimization of the engine during its operative life between overhauls. Simulation results of the suggested control system are also discus…