Search results for "LAB"
showing 10 items of 7932 documents
(Invited) The Effect of (La,Sr)MnO 3 Cathode Surface Termination on Its Electronic Structure
2017
La1-xSrxMnO3 (LSM) was one of the first perovskites used as SOFC cathode material. Its (001) surface has two possible terminations, LaSrO and MnO2, with quite different properties and oxygen reduction efficiencies. To avoid effects of surface polarity and the dipole moment across the material, symmetric non-stoichiometric slabs are commonly used in theoretical calculations with identical terminating planes on its both sides. We analyzed the dependence of the electronic structure (density of states) and charge distribution (effective atomic charges and chemical bond covalency) on the slab termination and Mn ion oxidation state (controlled by the Sr content and slab nonstoichiometry).
Collaborative processes during report writing of a science learning project: The nature of discourse as a function of task requirements
2000
The aim of this article is to specify how different aspects of task assignments are related to different types of student discourse during the report writing phase of a science learning project. A group of four ninth-grade students of the Finnish comprehensive school (about 15-year-olds) participated in a project work involving laboratory experiments, reading literature, and analysing and reporting research findings. The empirical data were collected through videotaping and interviews in authentic classroom settings. The results indicated that construction of shared, high-level understanding was quite rare in this case of small group interaction. As one of the main reasons for this, we sugg…
On the Ball-Marsden-Slemrod obstruction for bilinear control systems
2019
International audience; In this paper we present an extension to the case of $L^1$-controls of a famous result by Ball--Marsden--Slemrod on the obstruction to the controllability of bilinear control systems in infinite dimensional spaces.
A class of label-correcting methods for the K shortest paths problem
2001
In this paper we deal with the problem of finding the first K shortest paths from a single origin node to all other nodes of a directed graph. In particular, we define the necessary and sufficient conditions for a set of distance label vectors, on the basis of which we propose a class of methods which can be viewed as an extension of the generic label-correcting method for solving the classical single-origin all-destinations shortest path problem. The data structure used is characterized by a set of K lists of candidate nodes, and the proposed methods differ in the strategy used to select the node to be extracted at each iteration. The computational results show that: 1. some label-correct…
Hoffman's Error Bound, Local Controllability, and Sensitivity Analysis
2000
Our aim is to present sufficient conditions ensuring Hoffman's error bound for lower semicontinuous nonconvex inequality systems and to analyze its impact on the local controllability, implicit function theorem for (non-Lipschitz) multivalued mappings, generalized equations (variational inequalities), and sensitivity analysis and on other problems like Lipschitzian properties of polyhedral multivalued mappings as well as weak sharp minima or linear conditioning. We show how the information about our sufficient conditions can be used to provide a computable constant such that Hoffman's error bound holds. We also show that this error bound is nothing but the classical Farkas lemma for linear …
Periodicity vectors for labelled trees
2003
AbstractThe concept of a periodicity vector is introduced in the context of labelled trees, and some new periodicity theorems are obtained. These results constitute generalizations of the classical periodicity theorem of Fine and Wilf for words. The concept of a tree congruence is also generalized and the isomorphism between the lattice of tree congruences and the lattice of unlabelled trees (prefix codes) is established.
Highly irregular graphs with extreme numbers of edges
1997
Abstract A simple connected graph is highly irregular if each of its vertices is adjacent only to vertices with distinct degrees. In this paper we find: (1) the greatest number of edges of a highly irregular graph with n vertices, where n is an odd integer (for n even this number is given in [1]), (2) the smallest number of edges of a highly irregular graph of given order.
Controllability method for acoustic scattering with spectral elements
2007
We formulate the Helmholtz equation as an exact controllability problem for the time-dependent wave equation. The problem is then discretized in time domain with central finite difference scheme and in space domain with spectral elements. This approach leads to high accuracy in spatial discretization. Moreover, the spectral element method results in diagonal mass matrices, which makes the time integration of the wave equation highly efficient. After discretization, the exact controllability problem is reformulated as a least-squares problem, which is solved by the conjugate gradient method. We illustrate the method with some numerical experiments, which demonstrate the significant improveme…
El triángulo de la conciliación: percepciones cruzadas sobre la diversidad de género en el ámbito laboral
2013
0.066 IN-RECS (2011) Q2, 19/75 Sociología UEM
Performance of Spectral Fitting Methods for vegetation fluorescence quantification
2010
The Fraunhofer Line Discriminator (FLD) principle has long been considered as the reference method to quantify solar-induced chlorophyll fluorescence (F) from passive remote sensing measurements. Recently, alternative retrieval algorithms based on the spectral fitting of hyperspectral radiance observations, Spectral Fitting Methods (SFMs), have been proposed. The aim of this manuscript is to investigate the performance of such algorithms and to provide relevant information regarding their use. FLD and SFMs were used to estimate F starting from Top Of Canopy (TOC) fluxes at very high spectral resolution (0.12 nm) and sampling interval (0.1 nm), exploiting the O2-B (687.0 nm) and O2-A (760.6 …