Search results for "Statistic"
showing 10 items of 12520 documents
Korpusavusteinen virheanalyysi tarkkuuden kehityksestä EVK:n taitotasoilla A2–B2
2020
Artikkelissa tarkastellaan kielitaidon taitotasoittaista kehittymistä potentiaalisten esiintymien analyysin (Potential Occasion Analysis, Thewissen, 2015) avulla. Kehittymistä analysoidaan tarkkuuden näkökulmasta, ja sitä mitataan kohdekielen muoto- ja käyttökonventioista poikkeavien muotojen määrällä. Tutkimus on korpuspohjaista virheanalyysia (Corpus-aided Error Analysis, Dagneaux, Dennes & Granger, 1998), ja se perustuu taitotasoilla havaittujen, yhdeksään virheluokkaan sijoittuvien virheiden määrien tilastolliseen testaukseen. Aineistona on Kansainvälinen oppijansuomen korpus(ICLFI). Analyysi osoittaa, että merkittävintä kehitys on tasojen B1 ja B2 välillä; tasojen A2 ja B1 välillä tark…
Modeling long-range memory with stationary Markovian processes
2009
In this paper we give explicit examples of power-law correlated stationary Markovian processes y(t) where the stationary pdf shows tails which are gaussian or exponential. These processes are obtained by simply performing a coordinate transformation of a specific power-law correlated additive process x(t), already known in the literature, whose pdf shows power-law tails 1/x^a. We give analytical and numerical evidence that although the new processes (i) are Markovian and (ii) have gaussian or exponential tails their autocorrelation function still shows a power-law decay =1/T^b where b grows with a with a law which is compatible with b=a/2-c, where c is a numerical constant. When a<2(1+c) th…
Disease dispersion as a spatial interaction: The case of Flavescence Dorée
2020
International audience; Flavescence dorée is a serious and incurable vine disease transmitted by an insect vector. Focusing on its spatial diffusion and on its control with pesticides, this paper investigates the private strategies of wine producers and their socially optimal counterparts. The socially optimal regulation has to address two externalities regarding private treatment decisions: (a) the insufficient consideration of collective benefits from controlling the vector populations; (b) the failure to take into account environmental damage related to pesticide application. The probability of infection is estimated on French data from a spatial econometric specification. Three alternat…
A space-time branching process with covariates
2018
The paper proposes a stochastic process that improves the assessment of seismic events in space and time, considering a contagion model (branching process) within a regression-like framework. The proposed approach develops the Forward Likelihood for prediction (FLP) method including covariates in the epidemic component.
Crescita verde e sviluppo sostenibile. Approcci multidimensionali per la valutazione delle regioni italiane
2014
L’obiettivo principale di questa tesi di dottorato è quello di valutare la crescita verde e lo sviluppo sostenibile delle regioni italiane utilizzando un approccio multidimensionale finalizzato alla costruzione di indicatori compositi. L’analisi in componenti principali è utilizzata per sintetizzare le variabili che rappresentano dimensioni della crescita verde e della sostenibilità dello sviluppo. Particolare attenzione è dedicata ai metodi per derivare pesi di ponderazione endogeni, cioè basati sulla struttura dei dati. A differenza dell’analisi sulla crescita verde, dal confronto territoriale sullo sviluppo sostenibile sembra emergere il divario Nord-Sud, che caratterizza in particolare …
Geostatistics for Mapping Leaf Area Index over a Cropland Landscape: Efficiency Sampling Assessment
2010
This paper evaluates the performance of spatial methods to estimate leaf area index (LAI) fields from ground-based measurements at high-spatial resolution over a cropland landscape. Three geostatistical model variants of the kriging technique, the ordinary kriging (OK), the collocated cokriging (CKC) and kriging with an external drift (KED) are used. The study focused on the influence of the spatial sampling protocol, auxiliary information, and spatial resolution in the estimates. The main advantage of these models lies in the possibility of considering the spatial dependence of the data and, in the case of the KED and CKC, the auxiliary information for each location used for prediction pur…
KERNEL ESTIMATION OF THE TRANSITION DENSITY IN BIFURCATING MARKOV CHAINS
2023
We study the kernel estimator of the transition density of bifurcating Markov chains. Under some ergodic and regularity properties, we prove that this estimator is consistent and asymptotically normal. Next, in the numerical studies, we propose two data-driven methods to choose the bandwidth parameters. These methods are based on the so-called two bandwidths approach.
The dynamics of personal norms and the determinants of cultural homogeneity
2017
This article studies the emergence of cultural homogeneity in personal norms when the behavior of heterogeneous individuals is driven both by economic incentives and by personal norms. Agents participate in a team production game by choosing their level of costly effort. Norms evolve along the life cycle of the individuals according to two psychological forces: cognitive dissonance or consistency and informational conformity. The model sheds light on how primitive economic and behavioral parameters such as the distribution of skills, the income distribution, and the levels of materialism, conformism, and consistency in the group determine the long-run culture and its degree of cultural homo…
L’engagement des chercheurs dans la vulgarisation scientifique
2012
International audience; Quelle attitude ont les chercheurs vis-à-vis de la vulgarisation scientifique ? Voilà une question que tout médiateur scientifique est amené à se poser. Elle intéresse aussi les gouvernements et les grandes institutions scientifiques qui incitent les chercheurs à communiquer auprès du grand public et cherchent des solutions pour améliorer cette communication.Nous avons recherché des études et des enquêtes qui, depuis 1992, auraient proposé des diagnostics sur l’attitude, l’intérêt et surtout l’engagement des chercheurs dans cette pratique de vulgarisation. Notre propos s’articulera autour d’une étude clé, publiée en 2007 par Ellen Poliakoff et Thomas L Webb qui s’int…
Standard Asymptotic Response and Expected Runoff from Curve Number Theory
2015
The Standard Asymptotic response is a common finding with rainfall-runoff analysis with the Curve Number method. Widely-observed in data analyses, it is the secondary relationship between the data-defined CN and the causative rainfall P, for which the empirical fitting equation CN(P) = CN∞+ (100-CN∞)exp(-kP) has been found to fit well. This is an unexpected variation in the handbook methodology. It is investigated here on a “theoretical” basis by using the handbook tabled values of CN for the three AMC classes, I, II, and III; the storm-to-storm S (=1000/CN-10); and the observed 12-50-88 percent conditional probabilities for the ARC classes. With this, and treating S as a variable across th…