Search results for " Statistical Methods"
showing 9 items of 29 documents
Multi-State Quantum Dissipative Dynamics in Sub-Ohmic Environment: The Strong Coupling Regime
2015
We study the dissipative quantum dynamics and the asymptotic behavior of a particle in a bistable potential interacting with a sub-Ohmic broadband environment. The reduced dynamics, in the intermediate to strong dissipation regime, is obtained beyond the two-level system approximation by using a real-time path integral approach. We find a crossover dynamic regime with damped intra-well oscillations and incoherent tunneling and a completely incoherent regime at strong damping. Moreover, a nonmonotonic behavior of the left/right well population difference is found as a function of the damping strength.
Sequentially Forecasting Economic Indices Using Mixture Linear Combinations of EP Distributions
2021
This article displays an application of the statistical method moti- vated by Bruno de Finetti's operational subjective theory of probability. We use exchangeable forecasting distributions based on mixtures of linear com- binations of exponential power (EP) distributions to forecast the sequence of daily rates of return from the Dow-Jones index of stock prices over a 20 year period. The operational subjective statistical method for comparing distributions is quite different from that commonly used in data analysis, because it rejects the basic tenets underlying the practice of hypothesis test- ing. In its place, proper scoring rules for forecast distributions are used to assess the values o…
Modeling the Spatial Distribution of Xylella fastidiosa: A Nonstationary Approach with Dispersal Barriers
2022
Spatial species distribution models often assume isotropy and stationarity, implying that spatial dependence is direction-invariant and uniform throughout the study area. However, these assumptions are violated when dispersal barriers are present. Despite this, the issue of nonstationarity has been little explored in the context of plant health. The objective of this study was to evaluate the influence of barriers in the distribution of Xylella fastidiosa in the demarcated area in Alicante, Spain. Occurrence data from 2018 were analyzed through spatial Bayesian hierarchical models. The stationary model, illustrating a scenario without control interventions or geographical features, was com…
Matrices de pondérations et contexte spatio-temporel en économétrie spatiale
2013
International audience
Analítica o evocadora: el debate olvidado de la autoetnografía
2016
Existe la necesidad de una estrategia metodológica eficaz para sostener la investigación sobre la práctica profesional de los servicios sociales. La oposición entre el trabajo autoetnográfico de Carolyn ELLIS y Arthur BOCHNER (2000, 2006) y la propuesta analítica de Leon ANDERSON sirven como una lente a través de la cual explorar los aspectos clave de esta discusión. Mientras ELLIS y BOCHNER rechazan cualquier intento de abstracción o sistematización teórica, ANDERSON pretende tender puentes entre la tradición etnográfica y las formas emergentes de narrativa personal. Después de revisar la literatura autoetnográfica, concluyo que si bien la autoetnografía evocadora parece gozar del apoyo ma…
Les études hédoniques soutiennent-elles une valeur verte élevée dans le bâtiment ? Une réponse par la méta-analyse
2018
International audience; La place majeure occupée par le secteur du bâtiment dans la consommation d'énergie (40%) et les émissions de gaz à effet de serre (1/3 des émissions) explique le développement du débat scientifique axé sur la réduction de l'impact environnemental du bâtit et sur ses leviers. Ces dernières années ont notamment vu croitre une littérature considérable relative à la disposition à payer du public pour les bâtiments « verts » labélisés par des écolabels, cette « valeur verte » étant estimée dans la grande majorité des études via des modèles hédoniques. Dans cet article, nous proposons d'offrir une synthèse de ces résultats dans le cadre d'une méta-analyse portant sur plus …
CLUSTERING INCOMPLETE SPECTRAL DATA WITH ROBUST METHODS
2018
Abstract. Missing value imputation is a common approach for preprocessing incomplete data sets. In case of data clustering, imputation methods may cause unexpected bias because they may change the underlying structure of the data. In order to avoid prior imputation of missing values the computational operations must be projected on the available data values. In this paper, we apply a robust nan-K-spatmed algorithm to the clustering problem on hyperspectral image data. Robust statistics, such as multivariate medians, are more insensitive to outliers than classical statistics relying on the Gaussian assumptions. They are, however, computationally more intractable due to the lack of closed-for…
Enhancing Metastability by Dissipation and Driving in an Asymmetric Bistable Quantum System.
2018
The stabilizing effect of quantum fluctuations on the escape process and the relaxation dynamics from a quantum metastable state are investigated. Specifically, the quantum dynamics of a multilevel bistable system coupled to a bosonic Ohmic thermal bath in strong dissipation regime is analyzed. The study is performed by a non-perturbative method based on the real-time path integral approach of the Feynman-Vernon influence functional. We consider a strongly asymmetric double well potential with and without a monochromatic external driving, and with an out-of-equilibrium initial condition. In the absence of driving we observe a nonmonotonic behavior of the escape time from the metastable regi…
The ALICE experiment at the CERN LHC
2008
Journal of Instrumentation 3(08), S08002 (2008). doi:10.1088/1748-0221/3/08/S08002