1,721,220 research outputs found
A temporal logic approach to specify and to prove properties of finite state concurrent systems
No full textWe present a formalism to handle finite state concurrent systems in a mechanical way. In such a formalism we can axiomatically define concurrent systems by means of a branching time language. We show that, starting from the axiomatic description of a concurrent system, we can obtain automatically a finite Kripke model H such that theorem proving is reduced to model checking with respect to H. By means of such a formal procedure, we can model a large class of concurrent systems including Petri nets, CSP, Interaction Systems and so on. A tool has been implemented to produce a Kripke model from an axiomatical description of a concurrent system and to perform model checking on it
La population tuberculeuse dans l'agglomération marseillaise
No full textArnaud Jean-Luc, Masini A. La population tuberculeuse dans l'agglomération marseillaise. In: Méditerranée, deuxième série, tome 12, 1-1973. pp. 3-27
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Video Sequence Stabilization for Real-Time Remote Sensing Applications
No full textVideo sequence stabilization permits an accurate analysis of the video originate from sources as video cameras or IR sensors. In fact, a system of video stabilization allows the availability of aligned image sequences and, consequently, to improve the operator analysis of the scenario. In this paper different image processing methods are analyzed to remove the camera unwanted motions and reconstruct a stabilized sequence for real time applications. In particular three methodologies are compared in term of computational load and of the expected scenarios to determine the best strategies to be applied in a real time system
A short-medium time point evaluation of active breaks on selective and sustained attention in primary school: a pilot quasi-experimental study
Full text linkBackground: A growing body of evidence demonstrates the positive relationship between physical activity and executive function in children. Aims: This study aimed to examine the time course of the effectiveness of active breaks (ABs) in enhancing attention levels among second-grade primary school children compared to traditional teaching methods over a three-month period. Methods: Parents/guardians and teachers of both the experimental group (EG) and the control group (CG) completed a questionnaire assessing the psychometric characteristics of the sample. The EG participated in daily 10-min active breaks for three months, while the CG followed regular teaching methods. Selective attention (SeA, at 30 s) and sustained attention (SuA, at 120 s) were assessed at baseline and monthly (T0, T1, T2, and T3). Results: The EG consisted of 17 children (8.42 ± 0.39 years, 10 females), while the CG included 18 children (8.37 ± 0.42 years, 11 females). The EG generally exhibited higher psychometric scores, although teacher and parent perceptions varied in both groups. SeA levels improved significantly in both groups overtime, but EG demonstrated greater improvements, particularly three months after the introduction of active breaks (p < 0.001). A similar trend also for SuA (p < 0.001). A huge effect size shows larger increases during the third month for both SeA (ES = 1.97) and SuA (ES = 1.46) in favor of EG. Conclusions: Active breaks positively influenced both SeA and SuA. Their effectiveness increased over time, suggesting that a minimum duration of three months is necessary to achieve significant benefits compared to traditional teaching methods in primary education
IT strategies and corporate results: An empirical study
No full textVarious theoretical perspectives have been used in the literature to examine the relationship between IT strategy, competitive strategy and organizational performance. Yet, despite these efforts the nexus between IT, corporate strategy and performance remains still unclear. In this paper we develop and empirically test a stylised conceptual model that sheds further light on this nexus. Using a configurational approach on a sample of European companies from different sectors, we found that companies with stronger and more skilled IT departments adopt more focused competitive strategies and enjoy better performances in key functional areas compared to firms with weaker IT department
Evaluation of Multispectral Image Fusion Methods in Real Time Monitoring Applications
No full textIn this paper a methodology for fusion quality
evaluation is proposed in the case of many source images to be
fused in a single one. Various multiresolution fusion
methodologies are compared, and experimental results are
shown. Numerical results, in terms of quality of the fused images
and of computational load, are presented and discussed with
reference to avionic scenarios
Toward measuring the spin of obscured supermassive black holes: A critical assessment with disk megamasers
Full text linkContext. Mass and spin are two fundamental properties of astrophysical black holes. While some established indirect methods are adopted to measure both these properties of active galactic nuclei (AGN) when viewed relatively face-on, very few suggested methods exist to measure these properties when AGN are highly inclined and potentially obscured by large amounts of gas. Aims. In this context we explore the accuracy and performance of a recently proposed method to estimate the spin of AGN by fitting the accretion disk spectral energy distribution, when adapted for highly inclined and obscured systems, and in particular to a sample of six local water megamasers. For these sources the accretion rate and inclination angle are both known, allowing us to rely only on the AGN bolometric luminosity to infer their spin. Methods. Using the bolometric luminosity as a proxy for the accretion disk peak luminosity, we derived the expected bolometric luminosity as a function of spin. Then, we measured the bolometric luminosity of each source through X-ray spectroscopy, and compared it with the expected value to constrain the spin of the AGN. Results. The quality of the constraints depend critically on the accuracy of the measured bolometric luminosity, which is difficult to estimate in heavily obscured systems. Three out of six sources do not show consistency between the expected and measured bolometric luminosities, while the other three (four, when considering the [OIII] line as tracer of the bolometric luminosity) are formally consistent with high spin values. Conclusions. Our results suggest that this method, although promising (and possibly considered as a future calibrator for other methods) needs better observational data and further theoretical modeling to be successfully applied to obscured AGN and to infer robust results
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