Search results for "Biase"

A Bayesian analysis of the thermal challenge problem

2008

Abstract A major question for the application of computer models is Does the computer model adequately represent reality? Viewing the computer models as a potentially biased representation of reality, Bayarri et al. [M. Bayarri, J. Berger, R. Paulo, J. Sacks, J. Cafeo, J. Cavendish, C. Lin, J. Tu, A framework for validation of computer models, Technometrics 49 (2) (2007) 138–154] develop the simulator assessment and validation engine ( SAVE ) method as a general framework for answering this question. In this paper, we apply the SAVE method to the challenge problem which involves a thermal computer model designed for certain devices. We develop a statement of confidence that the devices mode…

Variance Estimation and Asymptotic Confidence Bands for the Mean Estimator of Sampled Functional Data with High Entropy Unequal Probability Sampling …

2013

For fixed size sampling designs with high entropy it is well known that the variance of the Horvitz-Thompson estimator can be approximated by the Hajek formula. The interest of this asymptotic variance approximation is that it only involves the first order inclusion probabilities of the statistical units. We extend this variance formula when the variable under study is functional and we prove, under general conditions on the regularity of the individual trajectories and the sampling design, that it asymptotically provides a uniformly consistent estimator of the variance function of the Horvitz-Thompson estimator of the mean function. Rates of convergence to the true variance function are gi…

Importance sampling correction versus standard averages of reversible MCMCs in terms of the asymptotic variance

2017

We establish an ordering criterion for the asymptotic variances of two consistent Markov chain Monte Carlo (MCMC) estimators: an importance sampling (IS) estimator, based on an approximate reversible chain and subsequent IS weighting, and a standard MCMC estimator, based on an exact reversible chain. Essentially, we relax the criterion of the Peskun type covariance ordering by considering two different invariant probabilities, and obtain, in place of a strict ordering of asymptotic variances, a bound of the asymptotic variance of IS by that of the direct MCMC. Simple examples show that IS can have arbitrarily better or worse asymptotic variance than Metropolis-Hastings and delayed-acceptanc…

Uniform convergence and asymptotic confidence bands for model-assisted estimators of the mean of sampled functional data

2013

When the study variable is functional and storage capacities are limited or transmission costs are high, selecting with survey sampling techniques a small fraction of the observations is an interesting alternative to signal compression techniques, particularly when the goal is the estimation of simple quantities such as means or totals. We extend, in this functional framework, model-assisted estimators with linear regression models that can take account of auxiliary variables whose totals over the population are known. We first show, under weak hypotheses on the sampling design and the regularity of the trajectories, that the estimator of the mean function as well as its variance estimator …

Varying-time random effects models for longitudinal data: unmixing and temporal interpolation of remote-sensing data

2008

Remote sensing is a helpful tool for crop monitoring or vegetation-growth estimation at a country or regional scale. However, satellite images generally have to cope with a compromise between the time frequency of observations and their resolution (i.e. pixel size). When concerned with high temporal resolution, we have to work with information on the basis of kilometric pixels, named mixed pixels, that represent aggregated responses of multiple land cover. Disaggreggation or unmixing is then necessary to downscale from the square kilometer to the local dynamic of each theme (crop, wood, meadows, etc.). Assuming the land use is known, that is to say the proportion of each theme within each m…

Life history of an Arctic crustacean Onisimus caricus (Amphipoda: Lysianassidae) as deduced from baited trap samples taken from Adventfjorden, Svalba…

2008

Combining Defocus and Photoconsistency for Depth Map Estimation in 3D Integral Imaging

2017

This paper presents the application of a depth estimation method for scenes acquired using a Synthetic Aperture Integral Imaging (SAII) technique. SAII is an autostereoscopic technique consisting of an array of cameras that acquires images from different perspectives. The depth estimation method combines a defocus and a correspondence measure. This approach obtains consistent results and shows noticeable improvement in the depth estimation as compared to a minimum variance minimisation strategy, also tested in our scenes. Further improvements are obtained for both methods when they are fed into a regularisation approach that takes into account the depth in the spatial neighbourhood of a pix…

On improving the accuracy of Visible Light Positioning system using deep autoencoder

2020

International audience; DC-biased optical Orthogonal Frequency DivisionMultiplexing (DCO-OFDM)-based visible light positioning (VLP)technology along with the Received Signal Strength(RSS) po-sitioning algorithm is widely used to achieve centimeter levelpositioning accuracy for incoming 5G era, especially indoorenvironment. However, the DCO-OFDM has the peak-to-averagepower ratio (PAPR) issue which imposes the nonlinear distortionand it will directly affect the positioning accuracy in the VLPsystem. The PAPR reduction scheme is urgently needed. There-fore, in this paper, the impact of PAPR reduction scheme onpositioning accuracy is investigated. The positioning accuracywith and without the s…

CORPORATE GOVERNANCE AND BEHAVIORAL FINANCE: FROM MANAGERIAL BIASES TO IRRATIONAL INVESTORS

2014

Corporate governance is concerned about the ways in which investors assure themselves of getting a return on their investment, on one hand, and is focus on motivating managers to increase the company profit, on the other hand (the agency theory). Corporate governance emerges from the interaction between managers and investors. Managers are often more likely to invest the extra cash-flow or profit than to return it to shareholders. But, both managers and investors are lees then fully rational. Sometimes their behavior is based on cognitive psychology. In this context, we are dealing with two problems: managerial biases and irrational investors. Managerial biases focus on the illusion of opti…

Etude du coaching d’un directeur de recherche de l’INRAE. Soutenu publiquement le 9 janvier 2023. Diplôme d’Université « Coaching & Management ». Par…

2023

The world of public research seems at first sight to be very little concerned by themanagement issues of the business world in which the right decisions must be taken and forwhich there is an obligation to perform. The very idea of coaching researchers seemsincongruous. The purpose of this study is to challenge this idea, by describing precisely whatthe profession of researcher is in the world of public research - their belonging to very complexstructures and the demanding challenges they have to face - then by studying thecontributions of cognitive-behavioural coaching methodologies. The analysis of the practiceshows that coaching based on constructivist psychology can lead to a better pra…