107 research outputs found
Adaptive query-based sampling of distributed collections
As part of a Distributed Information Retrieval system a de-scription of each remote information resource, archive or repository is usually stored centrally in order to facilitate resource selection. The ac-quisition ofprecise resourcedescriptionsistherefore animportantphase in Distributed Information Retrieval, as the quality of such represen-tations will impact on selection accuracy, and ultimately retrieval per-formance. While Query-Based Sampling is currently used for content discovery of uncooperative resources, the application of this technique is dependent upon heuristic guidelines to determine when a sufficiently accurate representation of each remote resource has been obtained. In this paper we address this shortcoming by using the Predictive Likelihood to provide both an indication of thequality of an acquired resource description estimate, and when a sufficiently good representation of a resource hasbeen obtained during Query-Based Sampling
Instability, Intermixing and Electronic Structure at the Epitaxial LaAlO3/SrTiO3(001) Heterojunction
The question of stability against diffusional mixing at the prototypical
LaAlO3/SrTiO3(001) interface is explored using a multi-faceted experimental and
theoretical approach. We combine analytical methods with a range of
sensitivities to elemental concentrations and spatial separations to
investigate interfaces grown using on-axis pulsed laser deposition. We also
employ computational modeling based on the density function theory as well as
classical force fields to explore the energetic stability of a wide variety of
intermixed atomic configurations relative to the idealized, atomically abrupt
model. Statistical analysis of the calculated energies for the various
configurations is used to elucidate the relative thermodynamic stability of
intermixed and abrupt configurations. We find that on both experimental and
theoretical fronts, the tendency toward intermixing is very strong. We have
also measured and calculated key electronic properties such as the presence of
electric fields and the value of the valence band discontinuity at the
interface. We find no measurable electric field in either the LaAlO3 or SrTiO3,
and that the valence band offset is near zero, partitioning the band
discontinuity almost entirely to the conduction band edge. Moreover, we find
that it is not possible to account for these electronic properties
theoretically without including extensive intermixing in our physical model of
the interface. The atomic configurations which give the greatest electrostatic
stability are those that eliminate the interface dipole by intermixing, calling
into question the conventional explanation for conductivity at this interface -
electronic reconstruction. Rather, evidence is presented for La indiffusion and
doping of the SrTiO3 below the interface as being the cause of the observed
conductivity
Observations sur la langue dans les lettres adressées a Š. Ljubić
Dans le présent article sont examinées certaines questions portant sur la langue et l\u27orthographe telles qu\u27on peut les constater dans les lettres faisant partie du legs de Š. Ljubić conservé dans les Archives historiques de Zadar. Leur date se situe autour de la moitié du 19e siècle.
Les auteurs de ces lettres sont I. Kukuljević Sakcinski, A. Torkvato Brlić, B. Petranović et Š. Starčević. Donc, un Zagrébien, un autre provenant de Slavonie et deux Dalmates, dont l\u27un était Serbe et l\u27autre Croate. De cette manière dans ces lettres sont représentées toutes les couches et structures et les principaux courants de la Croatie avec leurs vues sur la langue littéraire
Quantum Locality
It is argued that while quantum mechanics contains nonlocal or entangled
states, the instantaneous or nonlocal influences sometimes thought to be
present due to violations of Bell inequalities in fact arise from mistaken
attempts to apply classical concepts and introduce probabilities in a manner
inconsistent with the Hilbert space structure of standard quantum mechanics.
Instead, Einstein locality is a valid quantum principle: objective properties
of individual quantum systems do not change when something is done to another
noninteracting system. There is no reason to suspect any conflict between
quantum theory and special relativity.Comment: Introduction has been revised, references added, minor corrections
elsewhere. To appear in Foundations of Physic
The Projection Method for Reaching Consensus and the Regularized Power Limit of a Stochastic Matrix
In the coordination/consensus problem for multi-agent systems, a well-known
condition of achieving consensus is the presence of a spanning arborescence in
the communication digraph. The paper deals with the discrete consensus problem
in the case where this condition is not satisfied. A characterization of the
subspace of initial opinions (where is the influence matrix) that
\emph{ensure} consensus in the DeGroot model is given. We propose a method of
coordination that consists of: (1) the transformation of the vector of initial
opinions into a vector belonging to by orthogonal projection and (2)
subsequent iterations of the transformation The properties of this method
are studied. It is shown that for any non-periodic stochastic matrix the
resulting matrix of the orthogonal projection method can be treated as a
regularized power limit of Comment: 19 pages, 2 figure
Coordination in multiagent systems and Laplacian spectra of digraphs
Constructing and studying distributed control systems requires the analysis
of the Laplacian spectra and the forest structure of directed graphs. In this
paper, we present some basic results of this analysis partially obtained by the
present authors. We also discuss the application of these results to
decentralized control and touch upon some problems of spectral graph theory.Comment: 15 pages, 2 figures, 40 references. To appear in Automation and
Remote Control, Vol.70, No.3, 200
The contribution of corporate social responsibility to organisational commitment
This study investigates the relationship between organizational commitment and employee perceptions of corporate social responsibility (CSR) within a model that draws on social identity theory. Specifically, we examine the impact of three aspects of socially responsible behaviour on organizational commitment: employee perceptions of corporate social responsibility in the community, procedural justice in the organization and the provision of employee training. The relationship between organizational commitment and each aspect of CSR is investigated within a model that distinguishes between genders and includes a set of control variables that is drawn from the commitment literature (Meyer et al., 2002). The analysis is based on a sample of 4,712 employees drawn from a financial services company. The results emphasize the importance of gender variation and suggest both that external CSR is positively related to organizational commitment and that the contribution of CSR to organizational commitment is at least as great as job satisfaction.19 page(s
Combining Optimization and Randomization Approaches for the Design of Clinical Trials
t Intentional sampling methods are non-randomized procedures that select
a group of individuals for a sample with the purpose of meeting specific prescribed
criteria. In this paper we extend previous works related to intentional sampling,
and address the problem of sequential allocation for clinical trials with few patients.
Roughly speaking, patients are enrolled sequentially, according to the order in which they start the treatment at the clinic or hospital. The allocation problem consists in assigning each new patient to one, and only one, of the alternative treatment arms. The main requisite is that the profiles in the alternative arms remain similar with respect to some relevant patients’ attributes (age, gender, disease, symptom severity and others). We perform numerical experiments based on a real case study and discuss how to conveniently set up perturbation parameters, in order to yield a suitable balance between optimality – the similarity among the relative frequencies of patients in the several categories for both arms, and decoupling – the absence of a tendency to allocate each pair of patients consistently to the same arm
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